DE69223241T2 - Unit of work and this loading imaging device - Google Patents

Description

This invention relates to a replaceable process cartridge for an image forming apparatus such as an electrophotographic copier, a laser printer, a facsimile machine, a word processor or the like.

Such replaceable process cartridges are well known and have the advantage that they can be replaced by a user of the device without requiring the assistance of a trained service technician, thus extending the life of the device between major services that require the assistance of a trained technician.

This invention particularly relates to a replaceable process cartridge for an image forming apparatus comprising: a first and a second frame; a means for releasably locking the frames together to form a frame assembly; an electrophotographic photosensitive member mounted in the frame assembly; and a process means mounted in the frame assembly for acting on the photosensitive member.

Such a cartridge is described in patent document EP-A 0 453 963. The frame assembly of this cartridge is constructed of two frames which are releasably locked together to facilitate assembly of the cartridge and further to enable the frame assembly to be disassembled to recycle the cartridge. In the cartridge of EP-A 0 453 963, the locking means comprises a plurality of claws on one of the frames which engage with engaging portions on the other frame and a plurality of screws which pass through through holes in one of the frames to engage with the other frame.

However, such connection techniques can have the following disadvantages:

If the upper and lower frames are connected only by screws, in order to avoid any play or gap between the connected frames, a large number of screws must be used, thereby deteriorating the assemblability, which leads to increased costs.

On the other hand, there is no problem in connecting using locking claws and locking holes if the upper and lower frames have appropriate rigidity. However, if the rigidity of the frames is insufficient, the upper and lower frames may be displaced relative to each other. Furthermore, if an operator clamps the upper and lower frames together, a gap is likely to be generated between the frames and there is a fear that the claws may be damaged.

With an increasing number of recyclings of the same process cartridge, the locking force between the locking claw and the locking opening will be further reduced or disappear completely.

In addition, if the parts are press-fitted onto the process cartridge, as the number of recycles of the same process cartridge increases, clearance will occur between the assembled sections.

In view of the need to protect the environment, there is a strong desire to recycle the process cartridges by collecting the used process cartridges, disassembling them, replacing only the waste, damaged and/or sealed parts, and reassembling the cartridge. There is therefore a need to facilitate the recycling process and increase the number of times a process cartridge can be recycled.

The present invention is characterized by a plurality of alignment projections (14e, 14h; 15e) each provided on the first or on the second frame each of said projections being releasably engageable with a respective complementary recess (14d; 15f, 15a) in the other frame by movement along a respective axis such that the projection, when so engaged, is constrained by the respective recess against movement in a direction transverse to the respective axis, the axes being spaced apart from one another and generally parallel to one another.

The alignment projections and the associated recesses can be arranged to ensure excellent positioning accuracy of the frames and to prevent the frames from being separated when a torsional moment is applied thereto, without hindering ease of assembly and disassembly of the frames.

Some preferred features of the invention are set out in the appended dependent claims.

Particular embodiments of the present invention will now be described by way of non-limiting examples, with reference to the accompanying drawings, in which:

Fig. 1 is a side section of a copying machine in which a process cartridge according to a preferred embodiment of the invention is installed;

Fig. 2 is an axonometric view of the copying machine in a state where a basket is opened;.

Fig. 3 is an axonometric view of the copier in a state where a basket is closed.

Fig. 4 is a side section of the process cartridge;

Fig. 5 is an axonometric view of the process cartridge ;

Fig. 6 is an axonometric view of the process cartridge in an inverted state;

Fig. 7 is an axonometric exploded view of the process cartridge in a state where the upper frame and the lower frame are separated from each other;

Fig. 8 is an axonometric view of the lower frame showing its internal structure;

Fig. 9 is an axonometric view of the upper frame showing its internal structure;

Fig. 10 is a longitudinal section of a photosensitive drum of the process cartridge;

Fig. 11 is a schematic view for explaining the measurement of the charging noise;

Fig. 12 is a graph showing the measurement result of the loading noise with respect to a position of a filler;

Fig. 13 is an axonometric view of a grounding contact for the photosensitive drum;

Fig. 14 is an axonometric view of a grounding contact for the photosensitive drum, according to another embodiment;

Fig. 15 is an axonometric view showing an embodiment variant in which a non-forked grounding contact is used with the photosensitive drum;

Fig. 16 is a section of the non-forked grounding contact used with the photosensitive drum;

Fig. 17 is a side view showing a mounting structure for a loading roller;

Fig. 18A is an axonometric view of an exposure shutter; and Fig. 18B is a partial section of the exposure shutter;

Fig. 19 is a section showing a non-magnetic toner supply mechanism having a stirring blade;

Fig. 20 is a longitudinal sectional view showing a positional relationship between the photosensitive drum (9) and a developing sleeve (12d) and a structure for pressurizing the developing sleeve;

Fig. 21A is a section taken along the line A - A of Fig. 20, and Fig. 21B is a section taken along the line B - B of Fig. 20;

Fig. 22 is a section to explain the compressive force acting on the developing sleeve;

Fig. 23 is a cross-sectional view of a peel-off sheet in a state where an upper edge of the sheet is wavy;

Fig. 24A is an axonometric view showing a state in which a double-sided adhesive tape protrudes from a lower end of the peeling sheet, and Figs. 24B and 24C are views showing a state in which an adhering tool is adhered to the protruding double-sided adhesive tape;

Fig. 25A is an axonometric view showing a state in which the peeling sheet is adhered to a curved attachment surface with a lower end portion of the sheet being curved, and Fig. 25B is an axonometric view showing a state in which an upper end portion of the peeling sheet is tensioned by releasing the curvature of the attachment surface;

Fig. 26 is an axonometric view of a peeling blade according to another embodiment in which a width of the blade is linearly and gradually expanded from both ends to a middle portion thereof;

Fig. 27 is an axonometric view to explain the formation of the curvature of the peel-off sheet attachment surface by applying pressure to the surface;

Fig. 28 is a view showing states in which a recording medium is passed through a lower surface of the lower frame;

Fig. 29 is a section showing a state in which the photosensitive drum is finally assembled;

Fig. 30 is a section showing a state in which a developing sheet and a cleaning sheet are stuck;

Fig. 31 is an exploded view to explain the assembly of the process cartridge;

Fig. 32 is a view for explaining a position of guide members when the photosensitive drum of the process cartridge is assembled;

Fig. 33 is a section of a component in which the drum guides are arranged at the ends of blade support members;

Fig. 34 is an axonometric view to explain the mounting of the bearing members for the photosensitive drum and the developing sleeve;

Fig. 35 is a section of the photosensitive drum and the developing sleeve with the bearing members mounted thereon;

Fig. 36 is an axonometric view for explaining a cover film and a release tape;

Fig. 37 is an axonometric view showing a state in which the trigger band projects from a handle;

Fig. 38 is a schematic view showing a state in which the process cartridge is gripped by the hand of an operator;

Fig. 39A is a flow chart showing the assembly and shipping line for the process cartridge, and Fig. 39B is a flow chart showing the disassembly and cleaning line for the process cartridge;

Fig. 40 is an axonometric view showing a state in which the process cartridge is mounted in the image forming system;

Fig. 41 is an axonometric view showing a state in which the process cartridge of Fig. 24 is installed in the image forming system;

Fig. 42 is an axonometric view showing the arrangement of three contacts provided in the image forming system;

Fig. 43 is a section showing the structure of the three contacts;

Fig. 44 is a section to show the positioning of the relative position between the lower frame and a lens unit;

Fig. 45 is a section to explain the positioning of the relative position between the lower frame and an original glass carrier;

Fig. 46 is an axonometric view showing the mounting positions of the positioning pins;

Fig. 47 is a schematic side view showing the relationship between rotation axes of the drum and the sleeve and axis-supporting members for them, and a Transmission direction of the driving force from a drive wheel to a flange wheel of the photosensitive drum;

Fig. 48 is an axonometric exploded view of a development sleeve according to a variant embodiment in which it can be easily displaced;

Fig. 49 is a schematic side view of the development sleeve of Fig. 48;

Fig. 50 is a side sectional view showing a state in which an upper frame and a lower frame are unlocked;

Fig. 51 is a view showing gears and contacts attached to the photosensitive drum;

Fig. 52A is a side view of a developing sleeve receiving member according to another embodiment, and Fig. 52B is an end view of the receiving member of Fig. 52A;

Fig. 53 is a side view showing an arrangement in which the developing sheet and the cleaning sheet can be attached inside the image forming system by pins;

Fig. 54 is a side view showing a state in which the photosensitive drum is finally assembled, according to another embodiment;

Fig. 55 is a side section of bearing members for supporting the photosensitive drum and the developing sleeve according to a further embodiment;

Fig. 56 is a schematic view of a transmission mechanism for transmitting a driving force from a drive motor of the image forming system to various elements;

Figs. 57 and 58 are axonometric views showing a state in which the flange wheel of the photosensitive drum and a gear integral with the flange wheel project from the lower frame;

Fig. 59 is a view showing a gear chain for transmitting a driving force from the drive gear of the image forming system to the photosensitive drum and the transfer roller;

Figs. 60A and 60B are views showing different drive transmission mechanisms on developing sleeves where a magnetic toner is used and where a non-magnetic toner is used;

Fig. 61 is an axonometric exploded view for explaining the attachment of the cleaning blade;

Fig. 62 is a partial top view of the cleaning blade before installation;

Fig. 63 is a partial top view of the cleaning blade after installation;

Fig. 64, 65 and 66 are top views to explain the assembly of the cleaning blade;

Fig. 67 is a partial top view of a cleaning blade according to a further embodiment, wherein a mating projection of the cleaning blade has a rounded end;

Fig. 68 is a partial axonometric view of a cleaning blade according to a further embodiment variant in which a fitting projection of the cleaning blade is rounded by milling a bevelled portion thereof;

Fig. 69 is a partial top view of a cleaning blade according to a further embodiment variant, with a tape adhered to a beveled portion; and

Fig. 70 is a partial top view of a cleaning blade according to the other embodiment, with oil applied to a beveled portion.

First, a process cartridge according to a first embodiment and an image forming system using such a process cartridge will be explained with reference to the accompanying drawings.

The overall structure of a process cartridge and an image forming system that carries the process cartridge mounted thereon:

First, the overall structure of the image formation system will be briefly described. Fig. 1 is a Fig. 2 is an axonometric view of the copying machine with a basket opened, Fig. 3 is an axonometric view of the copying machine with the basket closed, Fig. 4 is a side section of the process cartridge, Fig. 5 is an axonometric view of the process cartridge, and Fig. 6 is an axonometric view of the process cartridge in an inverted state.

As shown in Fig. 1, the image forming system A operates such that image information is optically read from an original or document 2 by an original reading means 1. A recording medium fed on a sheet feed tray 3 or manually from the sheet feed tray 3 is conveyed by a conveying means 5 to an image forming section of the process cartridge B, where a developer (hereinafter referred to as "toner") image is transferred in dependence on the image information to the recording medium 4 via a transferring means 6. Thereafter, the recording medium 4 is sent to a fixing means 7, where the transferred toner image is permanently fixed to the recording medium 4. Then, the recording medium is ejected to an ejecting basket 8.

The process cartridge B constituting the image forming section serves to uniformly charge a surface of a rotating photosensitive drum (image bearing member) 9 by a charging means 10, then to form a latent image on the photosensitive drum 9 by projecting a light image read by the reading means 1 onto the photosensitive drum by means of an exposure means 11, and then to make the latent image visible as a toner image by a developing means 12. After the toner image is transferred to the recording medium 4 by the transfer means 6, the remaining toner remaining on the photosensitive drum is removed by a cleaning means 13.

The process cartridge B is formed as a cartridge unit by accommodating the photosensitive drum 9 and the like within frames having a first or upper frame 14 and a second or lower frame 15. Furthermore, in the illustrated embodiment, the frames 14, 15 are made of a high impact styrene resin (HIPS), and a thickness of the upper frame 14 is about 2 mm and a thickness of the lower frame 15 is about 2.5 mm. However, the material and thickness of the frames are not limited to the above values, but can be selected as appropriate.

Next, the various parts of the image forming system A and the process cartridge B which can be installed in the image forming system will be fully described.

Image Education System

First, various parts of the image formation system A will be explained

(Original Reading Resources)

The original reading means 1 serves to optically read the information written on the original, and, as shown in Fig. 1, it comprises an original glass carrier 1a arranged at an upper portion of a body 16 of the image forming system on which the original 2 is to be placed. An original holding plate 1b having a foam layer 1b1 on its inner surface is mounted on the original glass carrier 1a to perform an opening and closing movement. The original glass carrier 1a and the original holding plate 1b are fixed to the system body so as to be slidably movable in the direction from left to right in Fig. 1. On the other hand, a lens unit 1c is arranged below the original glass carrier 1a at the upper portion of the system body 16, and includes a light source 1c1 and a short focal length focusing lens assembly 1c2 inside it.

In this arrangement, when the original 2 is placed on the original glass carrier 1a with an image side thereof facing downward and the light source 1c1 is activated and the original glass carrier 1a is slid in the direction from left to right in Fig. 1, the light-sensitive drum 9 of the process cartridge B is exposed to the reflected light from the original 2 via the lens arrangement 1c2.

(Recording Medium Feeding Medium)

The feeding means 5 serves to feed the recording medium 4 placed on the sheet feeding tray 3 to the image forming section and to guide the recording medium to the fixing means 7. Specifically, after a plurality of recording mediums 4 are stacked on the sheet feed tray 3, or after a single recording medium 4 is manually inserted into the sheet feed tray 3, and the leading end(s) of the recording medium or media abuts against a gap between a sheet feed roller 5a and a friction pad 5b pressing against the roller, when a copy start button A3 is depressed, the sheet feed roller 5a is rotated to separate the recording medium 4 and feed it to a pair of register rollers 5c1, 5c2, which in turn feed the recording medium in accordance with the image forming operation. After the image forming process, the recording medium 4 is conveyed to the fixing means 7 via a conveying belt 5d and a guide member 5e, and then ejected onto the ejection basket 8 by a pair of ejection rollers 5f1, 5f2.

(Transmission medium)

The transfer means 6 serves to transfer the toner image formed on the photosensitive drum 9 to the recording medium 4 and, in the embodiment shown in Fig. 1, comprises a transfer roller 6. In particular, by pressing the recording medium 4 against the photosensitive drum 9 in the process cartridge B mounted in the image forming system by means of the transfer roller 6 provided in the image forming system and by applying to the transfer roller 6 a voltage having a polarity opposite to that of the toner image formed on the photosensitive drum 9 is formed, the toner image on the photosensitive drum 9 is transferred to the recording medium 4.

(Fixing agent)

The fixing means 7 is for the toner image transferred to the recording medium 4 by applying the tension to the transfer roller 6, and as shown in Fig. 1, it comprises a heat-resistant fixing film 7e wound around and extending between a drive roller 7a, a heating body 7c held by a holding member 7b, and a tension plate 7d. The tension plate 7d is biased by a tension spring 7f to apply a tension force to the film 7e. A pressing roller 7g is pressed against the heating body 7c with the film 7e therebetween so that the fixing film 7e is pressed against the heating body 7c with a predetermined force required for the fixing operation.

The heating body 7c is made of a heat-resistant material such as alumina, and has a heat-generating surface consisting of wire-shaped or plate-shaped members having a width of about 160 µm and a length (dimension perpendicular to the plane of Fig. 1) of about 216 mm, made of, for example, Ta₂N, and arranged on, for example, a lower surface of the holder 7b made of an insulating material or a composite material having an insulating and a protective layer made of, for example, Ta₂O, and covering the heat-generating surface. The lower surface of the heating body 7c is flat, and the front and rear ends of the heating body are rounded to allow the sliding movement of the fixing film 7e. The fixing film 7e is made of a heat-treated polyester and has a thickness of about 9 µm. The film can be rotated in the clockwise direction by the rotation of the drive roller 7a. When the recording medium 4 onto which the toner image has been transferred passes between the fixing film 7e and the pressure roller 7g, The toner image is fixed on the recording medium 4 by heat and pressure.

In order to thereby dissipate or discharge the heat generated by the fixing agent 7 from the image forming system, a fan impeller 17 is provided in the body 16 of the image forming system. The fan 17 is rotated, for example, when the copy start button A3 (Fig. 2) is depressed, so as to generate air currents a (Fig. 1) which flow into the image forming system from the recording medium supply inlet and flow out at the recording medium discharge outlet. The various parts, including the process cartridge B, are cooled by the air currents so that the heat does not remain in the image forming system.

(Recording media feed and eject baskets)

As shown in Figs. 1 to 3, the sheet supply basket 3 and the discharge basket 8 are respectively mounted on axes 3a, 8a within the system body 16 for pivotal movement in the directions b in Fig. 2, and for pivotal movement about the axes 3b, 8b in the directions c in Fig. 2. Locking projections 3c, 8c are formed on free ends of the baskets 3, 8 at both sides thereof. These projections can be inserted into locking recesses 1b2 formed on an upper surface of the original hold-down plate 1b. Therefore, as shown in Fig. 3, when baskets 3, 8 are folded inward so that the locking projections 3c, 8c are inserted into the corresponding recesses 1b2, the original glass platen 1a and the original hold-down plate 1b are prevented from sliding in the left and right directions. As a result, an operator can easily lift the image forming system A via handles 16a and transport it.

(Adjustment buttons for brightness etc.)

Furthermore, adjustment buttons for adjusting the brightness etc. are provided on the image forming system A. Briefly explained, a main switch A1 is provided in Fig. 2 to switch the image forming system on and off. A brightness adjustment dial A2 is used to adjust the basic brightness (of the copied image) in the image forming system. The copy start button A3, when depressed, starts the copying operation of the image forming system. A copy clear button A4, when depressed, interrupts the copying operation and clears the various setting states (e.g., the brightness setting state). A copy number counter button A5, when depressed, is used to set the number of copies. A brightness auto-adjust button A6, when depressed, automatically adjusts the brightness in the copying operation. A brightness adjustment select button A7 is provided so that the operator can adjust the brightness of the copies by turning this select button whenever necessary.

Process cartridge

Next, various parts of the process cartridge B which may be mounted in the image forming system A will be explained.

The process cartridge B comprises an image bearing member and at least one processing means. The processing means may comprise, for example, a charging means for charging a surface of the image bearing member, a developing means for forming a toner image on the image bearing member, and/or a cleaning means for removing the residual toner remaining on the image bearing member. As shown in Figs. 1 and 4 in the illustrated embodiment, the process cartridge B is formed as a cartridge unit which can be removably mounted in the body 6 of the image forming system by enclosing the charging means 10, the developing means 12 containing the toner (developer) and the cleaning means 13 which are arranged around the photosensitive drum 9 as the image bearing member, through a casing comprising the upper and lower frames 14, 15. The charging means 10, the exposure means 11 (opening 11a) and the toner container 12a of the developing means 12 are arranged within the upper frame 14, and the photosensitive drum 9, the developing sleeve 12d of the developing means 12 and the Cleaning means 13 are arranged within the lower frame 15.

The various parts of the process cartridge B will now be fully described as to the charging means 10, the exposure means 11, the developing means 12 and the cleaning means 13, in that order. In this case, Fig. 7 is a sectional view of the process cartridge with the upper and lower frames separated from each other, Fig. 8 is an axonometric view showing the internal structure of the lower frame, and Fig. 9 is an axonometric view showing the internal structure of the upper frame.

(Photosensitive drum)

In the illustrated embodiment, the photosensitive drum 9 comprises a cylindrical drum core 9a having a thickness of about 1 mm and made of aluminum, and an organic photosensitive layer 9b disposed on an outer peripheral surface of the drum core so that an outer diameter of the photosensitive drum 9 becomes 24 mm. The photosensitive drum is rotated in a direction shown by the arrow in response to the image forming operation by transmitting a driving force of a driving motor 54 (Fig. 56) of the image forming system to a flange gear 9c (Fig. 8) fixed to one end of the photosensitive drum 9.

During the image forming process, when the photosensitive drum 9 is rotated, the surface of the photosensitive drum 9 is uniformly charged by applying to the charging roller 10 (which is in contact with the drum 9) an oscillating voltage obtained by superimposing a direct current voltage on an alternating current voltage to the charging roller 10. In this case, in order to uniformly charge the surface of the photosensitive drum 9, the frequency of the alternating current voltage applied to the charging roller 10 must be increased. However, if the frequency increases beyond about 2000 Hz, the photosensitive drum 9 and the loading roller 10 is caused to vibrate, thereby generating the so-called "loading noise".

Note that when the AC voltage is applied to the charging roller, an electrostatic attractive force is generated between the photosensitive drum 9 and the charging roller 10 so that the attractive force becomes maximum at the maximum and minimum values of the AC voltage, whereby the charging roller 10 is attracted toward the photosensitive drum 9 while the charging roller is elastically deformed. On the other hand, at an intermediate value of the AC voltage, the attractive force becomes minimum, with the result that the elastic deformation of the charging roller 10 is returned to the flat state to separate the charging roller 10 from the photosensitive drum 9. Accordingly, the photosensitive drum 9 and the charging roller 10 are vibrated at the frequency twice that of the applied AC voltage. Furthermore, when the charging roller 10 is attracted to the photosensitive drum 9, the rotations of the drum and the roller are stopped, causing the vibration due to sticking and sliding, which also results in the charging noise.

In order to reduce the vibration of the photosensitive drum 9 in the illustrated embodiment as shown in Fig. 10 (section of the drum), a rigid or elastic filler 9d is arranged in the photosensitive drum 9. The filler 9d may be made of a metal such as aluminum, brass or the like, cement, ceramics such as gypsum, or a rubber material such as natural rubber, taking into consideration productivity of manufacturability, weight effect and cost. The filler 9d has a solid cylindrical shape or a hollow cylindrical shape and has an outer diameter smaller than the inner diameter of the photosensitive drum 9 by about 100 µm, and is inserted into the drum core 9a. It should be noted that a gap between the drum core 9a and the filler 9d is provided to have a value of 100 µm maximum, and an adhesive (for example, cyanoacrylate resin, epoxy resin or the like) 9e is applied to the outer surface of the filler 9d or the inner surface of the drum core 9a, and the filler 9d is inserted into the drum core 9a, thereby bonding these components together.

There will now be shown the results of experiments conducted by the inventors, in which the relationship between the position of the filler 9d and the sound pressure (noise level) was checked by changing the position of the filler 9d in the photosensitive drum 9. As shown in Fig. 11, the sound pressure was measured by a microphone M arranged at a distance of 30 cm from the front surface of the process cartridge B, which was arranged in a room having a background noise of 43 dB. As a result, as shown in Fig. 12, when the filler had a weight of 80 grams and was arranged at a middle position in the longitudinal direction of the photosensitive drum 9, the sound pressure was 54.5 - 54.8 dB. Whereas, when the filler had a weight of 40 grams and was arranged in a position shifted from the center position to the flange wheel 9c by 30 mm, the sound pressure was minimum. From this result, it was found that it was more effective to arrange the filler 9d in the photosensitive drum 9 so as to be shifted from the center position to the flange wheel 9c. The reason for this seems to be that the end of the photosensitive drum 9 is supported by the flange wheel 9c, while the other end of the drum 9 is supported by a bearing member 26 which has no flange, so that the construction of the photosensitive drum 9 is not symmetrical with respect to the center position in the longitudinal direction of the drum.

Therefore, in the embodiment shown in Fig. 10, the filler 9d in the photosensitive drum 9 is displaced from the center position c (in the longitudinal direction of the drum) toward the flange wheel 9c, that is, toward the drive transmission mechanism of the photosensitive drum 9. In the embodiment shown, a filler 9d having a hollow aluminum member having a length L3 of 40 mm and a weight of about 20 - 60 grams, preferably 35 - 45 grams (more preferably about 40 grams) is disposed within the photosensitive drum 9 having a length L1 of 257 mm, at a position shifted from the center position c to the flange wheel 9c by a distance L2 of 9 mm. By disposing the filler 9d within the photosensitive drum 9, the latter can be stably rotated, thereby suppressing the vibration due to the rotation of the photosensitive drum 9 in the image forming process. Therefore, even if the frequency of the AC voltage applied to the charging roller 10 is increased, it is possible to reduce the charging noise.

Furthermore, in the illustrated embodiment, as shown in Fig. 10, a grounding contact 18a is connected to the inner surface of the photosensitive drum 9, and the other end of the grounding contact abuts against a drum grounding contact pin 35a, thereby electrically grounding the photosensitive drum 9. The grounding contact 18a is arranged at the end of the photosensitive drum 9 opposite to the end near the flange wheel 9c.

The grounding contact 18a is made of a stainless spring steel, spring bronze phosphate or the like, and is attached to the bearing member 26. Specifically, as shown in Fig. 13, the grounding contact comprises a base portion 18a1 having a locking hole 18a2 into which a projection formed on the bearing member 26 can be inserted, and there are two portions 18a3 extending from the base portion 18a1, each arm portion being provided at its free end with a semicircular projection 18a4 projecting downward. When the bearing member 26 is attached to the photosensitive drum 9, the projections 18a4 of the grounding contact 18 are pressed against the inner surface of the photosensitive drum 9 by the elastic force of the arm portions 18a3. In this case, since the grounding contact 18a is in contact with the photosensitive drum 9 at several points (two points), the Reliability of the contact is improved, and since the grounding contact 18a is connected to the photosensitive drum 9 via the semicircular projections 18a4, the contact between the grounding contact and the photosensitive drum 9 is stabilized.

At this time, as shown in Fig. 14, the lengths of the arm portions 18a3 of the grounding contact 18a may be made different from each other. With this arrangement, since the positions at which the semicircular projections 18a4 are in contact with the photosensitive drum 9 are offset from each other in the circumferential direction of the drum, even if a crack portion extends in the axial direction of the inner surface of the photosensitive drum 9, both projections 18a4 do not simultaneously contact such a crack portion, thereby maintaining the grounding contact (between the contact and the drum) without failure. If the lengths of the arm portions 18a3 are made different from each other, the contact pressure between one of the arm portions 18a3 and the photosensitive drum is different from the contact pressure between the other arm portion and the drum. However, such a difference can be compensated for by, for example, changing the bending angles of the arm portions 18a3.

While in the illustrated embodiment the grounding contact 18a had two arm portions 18a3 as mentioned above, three or more arm contacts may be provided, or if the grounding contact is in contact with the inner surface of the photosensitive drum 9 without failure, a single arm portion 18a3 (not forked) having no projection may be used, as shown in Figs. 15 and 16.

If the contact pressure between the grounding contact 18a and the inner surface of the photosensitive drum 9 is too weak, the semicircular projections 18a4 cannot follow the unevenness of the inner surface of the photosensitive drum 9, thereby causing poor contact between the grounding contact and the photosensitive drum, as well as noise due to vibration of the arm. portion 18a3. In order to prevent such poor contact and noise, the contact pressure must be increased. However, if the contact pressure is too strong, when the image forming system is used for a long period of time, the inner surface of the photosensitive drum 9 may be damaged by the high pressure of the semicircular projections 18a4. Therefore, when the semicircular projections 18a4 pass over such a damaged portion, the vibration occurs, thereby causing the poor contact and the vibration noise. In consideration of the above facts, it is preferable that the contact pressure between the grounding contact 18a and the inner surface of the photosensitive drum 9 is set in a range between about 10 grams and about 200 grams. In addition, according to the results of experiments conducted by the inventors, when the contact pressure was less than about 10 grams, there was a fear that the poor contact might occur in response to the rotation of the photosensitive drum 9, thereby causing interference with radio broadcasts or other electronic devices. On the other hand, when the contact pressure was greater than about 200 grams, there was a fear that the inner surface of the photosensitive drum 9 might be damaged by the sliding contact between the inner surface of the drum and the grounding contact for a long period of time, thereby causing the abnormal noise and/or poor contact.

Although the generation of the above noise and the like cannot be completely avoided sometimes due to the condition of the surface of the photosensitive drum, it is possible to reduce the vibration of the photosensitive drum 9 by arranging the filler 9d inside the drum 9, and it is also possible to prevent the drum damage and the poor contact more effectively by applying a conductive lubricant to the contact area between the grounding contact 18a and the inner surface of the photosensitive drum 9. Furthermore, since the grounding contact 18a arranged on the bearing member 26 is away from the filler 9d, which is offset from the flange wheel 9c, the grounding contact can be easily attached to the bearing member.

(Charging medium)

The charging means serves to charge the surface of the photosensitive drum 9. In the illustrated embodiment, the charging means is one of the so-called contact charging type as disclosed in Japanese Patent Laid-Open No. 63-149669. In particular, as shown in Fig. 4, the charging roller 10 is rotatably supported on the inner surface of the upper frame 14 via a sliding bearing 10c. The charging roller 10 comprises a roller shaft 10b made of metal (for example, a conductive metal core made of iron, SUS or the like), an elastic rubber layer made of EPDM, NBR or the like and arranged around the roller shaft, and a urethane rubber layer in which carbon is dispersed and arranged around the elastic rubber layer, or comprises a roller shaft made of metal and a foamed urethane rubber layer in which carbon is dispersed. The roller shaft 10b of the charging roller 10 is supported by bearing sliding guide claws 10d of the upper frame 14 via the sliding bearing 10c so that it cannot be detached from the upper frame and so that it can be easily moved toward the photosensitive drum 9. The roller shaft 10b is biased by a spring 10a so that the charging roller 10 is pressed against the surface of the photosensitive drum 9. Therefore, the charging means is constituted by the charging roller 10 which is installed in the upper frame 14 via the bearing c. In the image forming process, when the charging roller 10 is driven by the rotation of the photosensitive drum 9, the surface of the photosensitive drum 9 is uniformly charged by applying the superposition of the AC voltage with the DC voltage to the charging roller 10 as described above.

Now, the voltage applied to the charging roller 10 will be described. Although the voltage applied to the charging roller 10 may be the DC voltage alone, in order to achieve the uniform charging, the threshold voltage obtained by superimposing the DC voltage and the AC voltage should be applied to the charging roller 10. Preferably, the threshold voltage obtained by superimposing the DC voltage and having a value of the peak-to-peak voltage more than twice as large as the charging start voltage when the DC voltage alone is used is used, and the AC voltage is applied to the charging roller 10 to improve the uniform charging (see Japanese Patent Laid-Open No. 63-149669). The "threshold voltage" described here means a voltage at which the voltage value is periodically changed as a function of time and having a peak-to-peak voltage more than twice as large as the charging start voltage when the photosensitive drum is charged by the DC voltage alone. Further, the waveform of the threshold voltage is not limited to the sine wave, but may be a square wave, a triangular wave, or a pulse wave. However, the sine wave having no higher harmonic components is preferable in view of reducing the charging noise. The DC voltage may include a voltage having the square wave obtained by periodically turning a DC voltage source ON and OFF, for example.

As shown in Fig. 17, the application of the voltage to the charging roller 10 is accomplished by pressing one end 18c1 of the charging bias contact 18c against a charging bias contact pin of the image forming system, as will be described later, and the other end 18c2 of the charging bias contact 18c against the metallic roller shaft 10b, thereby applying the voltage to the charging roller 10. At this time, since the charging roller 10 is biased to the right in Fig. 17 by the elastic contact 18c, the charging roller bearing 10c, which is located away from the contact 18c, has a hook-shaped stopper portion 10c1. Further, a stopper portion 10e projecting from the upper frame 14 is provided near the Contact 18c is arranged to prevent excessive axial movement of the loading roller 10 when the process cartridge B is dropped or vibrated.

In the illustrated embodiment, with the arrangement described above, the voltage of 1.6 - 2.4 KVVpp, - 600 VVDC (sine wave) is applied to the charging roller 10.

When the charging roller 10 is installed in the upper frame 14, first, the bearing 10c is held by the guide claws 10d of the upper frame 14, and then the roller shaft 10b of the charging roller 10 is inserted into the bearing 10c. Then, when the upper frame 14 is assembled with the lower frame 15, the charging roller 10 is pressed against the photosensitive drum 9 as shown in Fig. 4.

Here, the bearing 10c of the charging roller 10 is made of a conductive bearing material containing a large amount of carbon filler, and the voltage is applied to the charging roller 10 from the charging bias contact 18c via the metal spring 10a so that a stable charging bias can be provided.

(Exposure medium)

The exposure means 11 serves to expose the surface of the photosensitive drum 9 uniformly charged by the charging roller 10 with a light image from the reading means 1. As shown in Figs. 1 and 4, the upper frame 14 is provided with an opening 11a through which light from the lens array 1c2 of the image forming system can be projected onto the photosensitive drum 9. At this time, when the process cartridge B is removed from the image forming system A, if the photosensitive drum 9 is exposed to the ambient light through the opening 11a, there is a fear that the photosensitive drum will be damaged. To avoid this, a shutter member 11b is attached to the opening 11a so that when the process cartridge B is removed from the image forming system A, the opening 11a is closed by the shutter member 11b, and when the process cartridge is installed in the image forming system, the shutter member opens the opening 11a.

As shown in Figs. 18A and 18B, the shutter member 11b has an L-shaped cross section having a convex portion facing the outside of the cartridge, and is pivotally attached to the upper frame 14 via pins 11b1. A torsion coil spring 11c is mounted around one of the pins 11b1 so that the shutter member 11b is biased by the coil spring 11c to close the opening 11a in a state where the process cartridge B is dismounted from the image forming system A.

As shown in Fig. 18A, stopper portions 11b2 are formed on the outer surface of the shutter member 11b, so that when the process cartridge B is installed in the image forming system A and an upper opening/closing cover 19 (Fig. 1) to be opened with respect to the body 16 of the image forming system is closed, a projection 19a formed on the cover 19 abuts against the stopper portions 11b2, whereby the shutter member 11b is rotated in a direction shown by the arrow e (Fig. 18B) to open the opening 11a.

In the opening and closing operation of the shutter member 11b, since the shutter member 11b has an L-shaped cross section and the stopper portions 11b2 are arranged outside the outline of the cartridge B and near pivot pins 11b1 as shown in Figs. 4 and 18B, the shutter member 11b abuts against the projection 19a of the cover 19 outside the outline of the process cartridge B. As a result, even if the opening and closing angle of the shutter member 11b is small, a leading end of the rotary shutter member 11b is surely opened, thereby ensuring that the light from the lens array 1c2 arranged above the shutter member illuminates the photosensitive drum to form the good electrostatic latent image on the surface of the photosensitive drum 9. By forming the shutter member 11b as described above, when the process cartridge B is inserted into the image forming system is inserted, it is not necessary to retain the cartridge B from the shutter opening projection 9a of the image forming system cover 19, with the result that it is possible to shorten the stroke of the projection, whereby the process cartridge B and the image forming system A can be made small in size.

(Development funds)

Next, the developing agent 12 will be explained. The developing agent 12 serves to visualize the electrostatic latent image formed on the photosensitive drum 9 by the exposure agent as a toner image by toner. Although magnetic toner or non-magnetic toner may be used in this image forming system A, the developing agent in the process cartridge B in the illustrated embodiment comprises the magnetic toner as a one-component magnetic developer.

The binder resin of the one-component magnetic toner used in the developing process may be as follows or a mixture of the following polymers of styrene and substituents thereof such as polystyrene and polyvinyltoluene; styrene copolymer such as styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid-ethyl copolymer or styrene-acrylic acid-butyl copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, polyacrylic acid resin, resin, modified resin, rosin, phenol resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic petroleum resin, paraffin wax, carnauba wax or the like.

As for the coloring material added to the magnetic toner, it may be known as carbon black, copper phthalocyanine, iron black or the like. The fine magnetic particles contained in the magnetic toner may be of the material which is magnetizable when placed in the magnetic field, such as ferromagnetic powder of metals such as iron, Cobalt and nickel, powders of metal alloys or powders of compounds such as magnetite or ferrite.

As shown in Fig. 4, the developing means 12 for forming the toner image with the magnetic toner has a toner container 12a for containing the toner and a toner supply mechanism 12b disposed inside the toner container 12a and adapted to supply the toner. Further, the developing means is designed such that the developing sleeve 12d having a magnet 12c inside it is rotated to form a thin toner layer on a surface of the developing sleeve. When the toner layer is formed on the developing sleeve 12d, the developable frictional charges are applied to the electrostatic latent image on the photosensitive drum 9 by the friction between the toner and the developing sleeve 12d. In order to further regulate a thickness of the toner layer, a developing blade 12e is pressed against the surface of the developing sleeve 12d. The developing sleeve 12d is arranged in an opposed relation to the surface of the photosensitive drum 9 with a gap of about 100 - 400 µm therebetween.

As shown in Fig. 4, the magnetic toner supply mechanism 12b has supply members 12b1 made of polypropylene (PP), acrylobutadiene styrene (ABS), high impact styrene (HIPS) or the like, which are reciprocally movable in a direction shown by arrows f along a bottom surface of the toner container 12a. Each supply member 12b1 has a substantially triangular cross section and is provided with a plurality of long rod members extending along the rotation axis of the photosensitive drum (direction perpendicular to the plane of Fig. 4) for scraping the entire bottom surface of the toner container 12a. The rod members are connected to each other at their both ends to form an integral structure. Furthermore, three feed members 12b1 are provided, and the displacement range of the feed members is selected to be larger than a bottom width of the triangular cross section, so that the all of the toner can be scraped out from the bottom surface of the toner container. In addition, an arm member 12b2 is provided at its free end with a projection 12b6, thereby preventing the feed members 12b1 from shifting and becoming disorganized.

The feed member 12b1 has a locking projection 12b4 at its longitudinal end, which projection is rotatably fitted into a slot 12b5 formed in the arm member 12b2. The arm member 12b2 is rotatably mounted to the upper frame 14 via an axis 12b3, and is connected to an arm (not shown) disposed outside the toner container 12a. Further, a drive transmission means is connected to the feed members 12b1 so that when the process cartridge B is mounted in the image forming system A, the driving force from the image forming system is transmitted to the feed members to pivot the arm member 12b2 about the axis 12b3 by a predetermined angle. Incidentally, as shown in Fig. 7 and the like, the feed members 12b1 and the arm member 12b2 may be integrally formed of resin such as polypropylene, polyamide or the like so that they may be folded in a connecting portion therebetween.

Accordingly, in the image forming process, when the arm member 12b2 is pivoted by the predetermined angle, the feed members 12b1 are reciprocated along the bottom surface of the toner container 12a in the directions f between a state shown by the solid lines and a state shown by the broken lines. Therefore, the toner present near the bottom surface of the toner container 12a is fed to the developing sleeve 12d by the feed members 12b1. In this case, since each feed member 12b1 has a triangular cross section, the toner is scraped off by the feed members and smoothly fed to the inclined surfaces of the feed members 12b1. Therefore, it is difficult to stir up the toner near the developing sleeve 12d and therefore it is difficult to disturb the toner layer formed on the surface of the developing sleeve 12d.

Further, as shown in Fig. 4, a lid member 12f of the toner container 12a is provided with a depending member 12f1. A distance between a lower end of the depending member 12f1 and the bottom surface of the toner container is selected to be slightly larger than a height of the triangular cross section of each of the toner supply members 12b1. Accordingly, the toner supply member 12b1 is shifted back and forth between the bottom surface of the toner container and the dangling member 12f1, with the result that when the supply member 12b1 attempts to float up from the bottom surface of the toner container, such floating up is limited or regulated, thereby preventing the floating up of the supply members 12b1.

In this case, the image forming system A according to the embodiment shown can also accommodate a process cartridge containing the non-magnetic toner. In this case, the toner supply mechanism is driven to stir the non-magnetic toner near the developing sleeve 12d.

It is to be noted that when the non-magnetic toner is used, as shown in Fig. 19, an elastic roller 12g rotated in the same direction as the developing sleeve 12d feeds the non-magnetic toner from the toner container 12a through the toner supply mechanism 12h to the developing sleeve 12d. In this case, in the gap between the developing sleeve 12d and the elastic roller 12g, the toner on the elastic roller 12g is frictionally charged by the sliding contact between the toner and the developing sleeve 12d to electrostatically adhere to the developing sleeve 12d. Thereafter, during the rotation of the developing sleeve 12d, the non-magnetic toner adhering to the developing sleeve 12d enters an abutment portion between the developing blade 12e and the developing sleeve 12d to form the thin toner layer on the developing sleeve, and the toner is frictionally charged by the sliding contact between the toner and the developing sleeve, with a polarity sufficient to develop the electrostatic latent image. However, if the toner remains on the developing sleeve 12d, the remaining toner is mixed with the new toner to supply the developing sleeve 12d, and is fed into the abutment area between the developing sleeve and the developing blade 12e. The remaining toner and the new toner are frictionally charged by the sliding contact between the toner and the developing sleeve 12d. However, in this case, although the new toner is charged with the appropriate charge, since the remaining toner is further charged with the appropriate charge from the state in which it has already been charged, it is overcharged. The overcharged or excessively charged toner has an attractive force (to the developing sleeve 12d) which is stronger than that of the appropriately charged toner, thereby making it more difficult to use in the developing process.

To avoid this, in the illustrated embodiment concerning the process cartridge containing the non-magnetic toner as shown in Fig. 19, the non-magnetic toner supply mechanism 12h thereof comprises a rotary member 12h1 disposed in the toner container 12a, which rotary member 12h1 has an elastic agitating blade 12h2. When the non-magnetic toner cartridge is installed in the image forming system A, the drive transmission means is connected to the rotary member 12h1 so that the latter is rotated by the image forming system in the image forming process. When the image is formed in this way by using the cartridge containing the non-magnetic toner and built in the image forming system, the toner in the toner container 12a is strongly agitated by the agitating blade 12h2. As a result, the toner near the developing sleeve 12d is also agitated to be mixed with the toner in the toner container 12a, whereby the charged charges removed from the developing sleeve 12d are dispersed in the toner inside the toner container to prevent the deterioration of the toner.

In this way, the developing sleeve 12d on which the toner layer is formed is arranged in an opposed position with respect to the photosensitive drum 9 with a narrow gap therebetween (about 300 µm with respect to the process cartridge containing the magnetic toner or about 200 µm with respect to the process cartridge containing the non-magnetic toner). Accordingly, in the illustrated embodiment, stopper rings each having an outer diameter larger than that of the developing sleeve by an amount corresponding to the narrow gap are arranged near both axial ends of the developing sleeve 12d and outside the toner layer formation region so that these rings abut against the photosensitive drum 9 in regions outside the latent image formation region.

Now, the positional relationship between the photosensitive drum 9 and the developing sleeve 12d will be explained. Fig. 20 is a longitudinal sectional view showing a positional relationship between the photosensitive drum 9 and the developing sleeve 12d and a structure for pressing the developing sleeve, Fig. 21A is a sectional view taken along the line A - A of Fig. 20, and Fig. 21A is a sectional view taken along the line B - B of Fig. 20.

As shown in Fig. 20, the developing sleeve 12d on which the toner layer is formed is arranged in an opposed relation to the photosensitive drum 9 with a narrow gap therebetween (about 200 - 300 µm). In this case, the photosensitive drum 9 is rotatably supported on the lower frame 15 by supporting a rotation axis 9f of the flange gear 9c at one end of the drum via a support member 33. The other end of the photosensitive drum 9 is also rotatably supported on the lower frame 15 via a bearing portion 26a of the bearing member 26 fixed to the lower frame. The developing sleeve 12d has the above-described stopper rings 12d1 each having an outer diameter larger than that of the developing sleeve by an amount corresponding to the narrow gap, these rings being in near both axial ends of the developing sleeve and outside the toner layer forming region, so that these rings abut against the photosensitive drum 9 in the areas outside the latent image forming region.

Further, the developing sleeve 12d is rotatably supported by the sleeve bearings 12i arranged between the stopper rings 12d1 near both axial ends of the developing sleeve and outside the toner layer forming area, which sleeve bearings 12i are mounted on the lower frame 15 in such a manner that they can be easily displaced in the directions shown by the arrow g in Fig. 20. Each sleeve bearing 12i has a rearwardly projecting projection around which a compression spring 12j is mounted, one end of which abuts against the lower frame 15. Accordingly, the developing sleeve 12d is always biased toward the photosensitive drum 9 by these compression springs. With this arrangement, the stop rings 12da always abut against the photosensitive drum 9, with the result that the predetermined gap between the developing sleeve 12d and the photosensitive drum 9 is always maintained, whereby the driving force is transmitted to the flange gear 12c of the photosensitive drum 9 and a sleeve gear 12k of the developing sleeve 12d which meshes with the flange gear 9c.

The sleeve gear 12k also constitutes a flange portion of the developing sleeve 12d. In this regard, according to the embodiment shown, the sleeve gear 12k and the flange portion are integrally formed from a resin material (e.g., polyacetylene resin). Furthermore, a metal pin 12d2 having a small diameter (e.g., made of stainless steel) and having one end rotatably supported by the lower frame 15 is press-fitted into the sleeve gear 12k (flange portion) at its center. This metal pin 12d2 acts as a rotation axis at one end of the developing sleeve 12d. Since according to the embodiment shown, the sleeve gear and the flange portion can be integrally formed from resin, it is possible to to facilitate the manufacture of the developing sleeve and to make the developing sleeve 12d and the process cartridge B lightweight.

The sliding directions of the sleeve bearings 12i will now be explained with reference to Fig. 22. First, the driving of the developing sleeve 12d will be described. When the driving force is transmitted from the driving source (driving motor 54) of the image forming system to the flange gear 9c and then transmitted from the flange gear 9c to the sleeve gear 12k, the engaging force between the gears is directed in a direction inclined or shifted with respect to a tangent that contacts the pitch circle of the flange gear 9c and a pitch circle of the sleeve gear 12k by a pressure angle (20° in the illustrated embodiment). Therefore, this engaging force is directed in a direction shown by the arrow P in Fig. 22 (θ 20°). In this case, when the sleeve bearings 12i slide in a direction parallel to a line connecting the fulcrum of the photosensitive drum 9 and the fulcrum of the developing sleeve 12d, if the engaging force P is divided into a force component Ps of a horizontal direction parallel to the sliding direction and a force component Ph of a vertical direction perpendicular to the sliding direction as shown in Fig. 22, the force component of the horizontal direction parallel to the sliding direction is directed away from the photosensitive drum 9. As a result, as for the driving of the developing sleeve 12d, the distance between the photosensitive drum 9 and the developing sleeve 12d is easily changed in accordance with the engaging force between the flange gear 9c and the developing sleeve 12k, with the result that the toner on the developing sleeve 12d cannot be properly moved onto the photosensitive drum 9, which deteriorates the developing properties.

To avoid this, in the embodiment shown, as shown in Fig. 21A, taking into account the transmission of the driving force from the flange wheel 9c to the sleeve wheel 12k, the sliding direction of the sleeve bearing 12i on the drive side (the side on which the sleeve gear 12k is arranged) coincides with the directions indicated by the arrow Q. Note that an angle ? formed between the direction of the engaging force P (between the flange gear 9c and the sleeve gear 12k) and the sliding direction is set to have a value of about 90° (92° in the illustrated embodiment). With this arrangement, the force component Ps of the horizontal direction parallel to the sliding direction is negligible, and in the illustrated embodiment, the force component Ps acts to slightly bias the developing sleeve 12d toward the photosensitive drum 9. In such a case, the developing sleeve 12d is pressurized to an extent equal to the spring force ?. of the compression springs 12j to keep the distance between the photosensitive drum 9 and the developing sleeve 12d constant, thereby ensuring proper development.

Next, the sliding direction of the slide bearing 12i on the non-drive side (side on which the sleeve gear 12k is not arranged) will be explained. Since on the non-drive side, unlike the drive side described above, the slide bearing 12i does not receive a driving force as shown in Fig. 218, the sliding direction of the slide bearing 12i is selected to be substantially parallel to a line connecting a center of the photosensitive drum 9 and a center of the developing sleeve 12d.

In this way, when the developing sleeve 12d is pressed to the photosensitive drum 9 by making the pressure angle for pressing the developing sleeve 12d on the driving side different from that on the non-driving side, the positional relationship between the developing sleeve 12d and the photosensitive drum 9 is always maintained in an appropriate form, enabling appropriate development.

The sliding direction of the plain bearing 12i on the drive side can be set so that it is essentially parallel to the line that passes through the center of the photosensitive drum 9 and the center of the developing sleeve 12d, as in the case of the non-driven side. Note that, as described in the above-mentioned embodiment, at the drive side, since the developing sleeve 12d is pushed away from the photosensitive drum 9 by the force component Ps (the engagement force between the flange gear 9c and the sleeve gear 12k) directed in the sliding direction of the slide bearing 12i, in this embodiment, the urging force of the compression spring 12j on the drive side can be set to have a value larger than that on the non-driven side by an amount corresponding to the force component Ps. This means that when the urging force of the urging spring 12j on the developing sleeve 12d on the non-driven side is P, the urging force Ps of the urging spring 12j on the driven side is set to satisfy a relationship of P2 = P1 + Ps, with the result that the developing sleeve 12d is always subjected to the appropriate urging force, thereby ensuring a constant clearance between the developing sleeve and the photosensitive drum 9.

(Cleaning supplies)

The cleaning means 13 serves to remove the residual toner remaining on the photosensitive drum 9 after the toner image on the photosensitive drum 9 is transferred to the recording medium 4 by the transfer means 6. As shown in Fig. 4, the cleaning means 13 comprises an elastic cleaning blade 13a which contacts the surface of the photosensitive drum 9 and is adapted to remove or scrape off the residual toner remaining on the photosensitive drum 9, a peeling blade 13b which lightly contacts the surface of the photosensitive drum 9 and is arranged below the cleaning blade 13 to collect the removed toner, and a toner waste container 13c for collecting the toner waste collected by the blade 13b. Peeling blade 13b lightly contacts the surface of the photosensitive drum 9 and serves to allow the passage of the residual toner remaining on the photosensitive drum, but to direct the toner removed from the photosensitive drum 9 by the cleaning blade 13a in a direction away from the surface of the photosensitive drum 9.

A method of attaching the peeling sheet 13b will now be described. The peeling sheet 13b is attached to a mounting surface 13d of the waste toner container 13c by a double-sided adhesive tape 13e. In this case, the waste toner container 13c is made of a resin material (for example, high impact styrene (HIPS) or the like), and has a slightly uneven surface. Therefore, as shown in Fig. 23, if the double-sided adhesive tape 13e is stuck only to the mounting surface 13d and the peeling sheet 13b is attached only to the double-sided adhesive tape 13e, there is a fear that a free end of the peeling sheet 13b (which contacts the photosensitive drum 9) is curled as shown by x. If such a curled edge x of the peeling sheet 13b is generated, the peeling sheet 13b is not in close contact with the surface of the photosensitive drum 9, so that it cannot surely pick up the toner removed by the cleaning sheet 13a.

To avoid this, it is considered that when the peeling sheet 13b is attached to the attachment surface as shown in Fig. 24A, the attachment surface 13d at a lower portion of the waste toner container is pulled downward by a pulling tool 20 to elastically deform the attachment surface to form a curve, and then the peeling sheet 13b is stuck to the curved attachment surface, and thereafter, the curve of the attachment surface is released to apply the tension to the free edge of the peeling sheet 13b, thereby preventing the free edge from becoming wavy. However, in the current small process cartridges B, since the dimension of the attachment surface 13d is small, when the peel-off sheet 13b is stuck onto the curved attachment surface 13d, As shown in Fig. 24A, both ends or corners 13b1 of the peel sheet 13b will project downward from the mounting surface 13d. And if the peel sheet 13b projects downward from the mounting surface 13d, then, as can be seen from the section of Fig. 1, there is a fear that the recording medium 4 will interfere with the projecting peel sheet 13b.

Furthermore, when the release sheet 13b is attached to the curved attachment surface 13d as shown in Fig. 24A, the double-sided adhesive tape 13e will protrude from the lower end of the release sheet 13b. Therefore, if the peeling sheet 13b is pressed against the double-sided adhesive tape 13e by an adhesive tool 21 in this state as shown in Fig. 24b, the protruding portion of the double-sided adhesive tape 13e will stick to the adhesive tool 21, with the result that when the adhesive tool 21 is removed as shown in Fig. 24C, the double-sided adhesive tape 13e will be peeled off from the attachment surface 13d, thereby causing the poor attachment of the peeling sheet 13b.

To avoid this, in the illustrated embodiment as shown in Fig. 25A, the configuration of the lower end of the peeling sheet 13b becomes substantially the same as the curvature configuration of the attachment surface 13d curved by the pulling tool 20. Note that a width of the peeling sheet 13b changes from both ends in the longitudinal direction toward a central portion so that it becomes larger in the latter case than in the former (for example, the width in the central portion is about 7.9 mm and the width at both ends is about 7.4 mm). In this way, when the peeling sheet 13b is attached to the attachment surface 13d, the double-sided adhesive tape 13e does not protrude from the peeling sheet 13b. Further, when the pulling tool 20 is removed to release the curvature of the mounting surface 13-d to thereby apply the tension to the upper edge of the peeling sheet 13b as shown in Fig. 25b, the lower end of the peeling sheet 13b does not protrude downward from the mounting surface 13d. Therefore, the above-described interference between the recording medium 4 and the peeling sheet 13b can be avoided. and the poor attachment of the peel-off sheet 13b can be prevented.

At this time, it is desirable that the lower edge of the stripping blade 13b be straight in view of the manufacturability and durability of a working tool. Therefore, as shown in Fig. 26, the width of the stripping blade 13b in a straight line can be changed so that the width at a central portion becomes larger than that at both ends in the longitudinal direction in accordance with the degree of curvature of the attachment surface 13d. While in the above-described embodiment, the attachment surface 13d was curved by being tensioned by the tensioning tool 20, it is to be understood that, as shown in Fig. 27, the attachment surface 13d may be curved by pressing the toner container partition plates 13c1 formed integrally with the attachment surface 13d by pressing tools 20a.

Furthermore, while in the illustrated embodiment, the peel-off sheet attachment surface 13d was formed on the lower portion of the waste toner container 13c, the peel-off sheet 13b may be adhered to a metal plate attachment surface formed independently of the waste toner container 13c, and then the metal plate may be incorporated into the waste toner container 13c.

In the embodiment shown, the peel-off sheet 13b is made of polyethylene terephthalate (PET) and has a thickness of about 38 µm, a length of about 241.3 mm, a width in the middle of about 7.9 mm, a width at the ends of about 7.4 mm, and a suitable radius of curvature of about 14556.7 mm.

(Upper and lower frame)

Next, the upper and lower frames 14, 15 which constitute the casing of the process cartridge B will be described. As shown in Figs. 7 and 8, the photosensitive drum 9, the developing sleeve 12d and the developing blade 12e of the developing agent 12, the cleaning agent 13 are provided on the lower frame 15. On the other hand, as shown in Figs. 7 and 9, the charging roller 10, the toner container 12a of the developing agent 12 and the toner supply mechanism 12b are provided in the upper frame 14.

In order to assemble the upper and lower frames 14, 15, four pairs of locking claws 14a are formed integrally with the upper frame 14 and arranged at equal intervals from each other in a longitudinal direction of the upper frame. Similarly, locking holes 15a and locking projections 15b for engagement by the locking claws 14a are formed integrally on the lower frame 15. Accordingly, when the upper and lower frames 14, 15 are pressed against each other with force to engage the locking claws 14a through the corresponding locking holes 15a and the locking projections 15b, the upper and lower frames 14, 15 are connected to each other. In order to secure the connection between the upper and lower frames, as shown in Fig. 8, a locking claw 15c and a locking hole 15d are formed near both the longitudinal ends of the lower frame 15, while as shown in Fig. 9, a locking hole 14b (to engage with the locking claw 15c) and a locking claw 14c (to engage with the locking hole 15d) are formed near both the longitudinal ends of the upper frame 14.

When the parts constituting the process cartridge B are separately contained in the upper and lower frames 14, 15 as described above, by arranging the parts that should be positioned with respect to the photosensitive drum 9 (for example, developing sleeve 12d, developing blade 12e and cleaning blade 13a) within the same frame (lower frame 15 in the illustrated embodiment), it is possible to ensure the excellent positioning accuracy of each part and to facilitate the assembly of the process cartridge B. Furthermore, as shown in Fig. 8, the fitting recesses 15n in the lower frame 15 near one of its side edges. On the other hand, as shown in Fig. 9, fitting projections 14h (to be inserted into the corresponding fitting recesses 15n) are formed on the upper frame 14 near one of its side edges, at intermediate positions between the adjacent locking claws 14a.

Furthermore, in the illustrated embodiment, as shown in Fig. 8, fitting projections 15e are formed on the lower frame 15 near two corners thereof, while fitting recesses 15f are formed in the lower frame near the other two corners. On the other hand, as shown in Fig. 9, fitting recesses 14d (to be engaged with the corresponding fitting projections 14e) are formed on the upper frame 14 near two corners thereof, while fitting projections 14e (to be inserted into the corresponding fitting recesses 15f) are formed in the lower frame near the other two corners. Accordingly, when the upper and lower frames 14, 15 are joined together by inserting the fitting projections 14h, 14e, 15e (of the upper and lower frames 14, 15) into the corresponding fitting recesses 15n, 15f, 14d of the upper and lower frames 14, 15, the upper and lower frames are securely joined together so that even if a torsional moment is applied to the upper and lower frames 14, 15 which are joined together, they are not disassembled.

In this case, the positions of the above-described fitting projections and fitting recesses can be changed as long as the upper and lower frames are not disassembled by any torsional moment applied to them.

Further, as shown in Fig. 9, a protective cover 22 is rotatably mounted on the upper frame 14 via pivot pins 22a. The protective cover 22 is biased in a direction shown by arrow h in Fig. 9 by torsion coil springs (not shown) arranged around the pivot pins 22a, so that the protective cover 22 can support the photosensitive Drum 9 in the state where the process cartridge B is removed from the image forming system A, as shown in Fig. 4.

Specifically, as shown in Fig. 1, the photosensitive drum 9 is designed to be exposed through an opening 15g formed in the lower frame 15 and facing the transfer roller 6 to enable the toner image to be transferred from the photosensitive drum 9 to the recording medium 4. However, in the state where the process cartridge B is removed from the image forming system A, when the photosensitive drum 9 is exposed to the outside, it is damaged by the ambient light and the dirt and the like adhering to the photosensitive drum 9. To prevent this, when the process cartridge B is removed from the image forming system A, the opening 15g is closed by the protective cover 22, thereby protecting the photosensitive drum 9 from the ambient light and dirt. At this time, when the process cartridge B is installed in the image forming system A, the protective cover 22 is rotated by a tilting mechanism (not shown) to release the photosensitive drum 9 through the opening 15g.

Furthermore, as can be seen from Fig. 1, in the illustrated embodiment, the lower surface of the lower frame 15 also serves as a guide for conveying the recording medium 4. The lower surface of the lower frame is formed as a double-sided guide portion 15h1 and a stepped central guide portion 15h2 (Fig. 6). The longitudinal length (i.e., the distance between the steps) of the central guide portion 15h2 is about 102 - 120 mm (107 mm in the illustrated embodiment), which is slightly larger than a width (about 100 mm), and the depth of the step is selected to have a value of about 0.8 - 2 mm. With this design, the middle guide section 15h2 enlarges the conveying space for the recording medium 4, with the result that even if a thicker and harder sheet, such as a postcard, business card or envelope is used as the recording medium 4, such a thicker sheet does not interfere with the guide surface of the lower frame 15, thereby preventing jamming of the recording medium. On the other hand, when a thin sheet having a width greater than that of the postcard, such as a full sheet, is used as the recording medium, since such a sheet (recording medium) is guided by the both side guide portions 15h1, it is possible to convey the sheet without slippage.

Now, the lower surface of the lower frame 15 serving as a conveyance guide for the recording medium will be described more concretely. As shown in Fig. 28, the both-side guide portion 15h1 may be bent by an amount La (= 5 - 7 mm) with respect to a tangential direction X concerning a gap N between the photosensitive drum 9 and the transfer roller 6. Since the two side guide portions 15h1 are formed on the lower surface of the lower frame 15, which is designed to provide the necessary space between the lower frame and the developing sleeve 12d, as well as the necessary space to sufficiently supply the toner to the developing sleeve, such guide portions can be determined by the posture of the developing sleeve 12d, which is selected to obtain the optimum developing state. If the lower surface of the side guide portions is brought closer to the tangent X, the thickness of the lower portion of the lower frame 15 is reduced, causing a problem regarding the strength of the process cartridge B.

Furthermore, the position of a lower end 13f of the cleaning means 13 is determined by the positions of the cleaning blade 13a, the peeling blade 13b and the like constituting the cleaning means 13, as will be described later, and is selected to give a distance Lb (= 3 - 5 mm) which prevents interference with the recording medium 4 being conveyed. In the embodiment shown, the angle β between a vertical line passing through the pivot point of the photosensitive drum 9 shown in Fig. 28 and a line connecting the pivot point of the photosensitive drum 9 and the pivot point of the transfer roller 6, a selection is made to have a value of 5 - 20 degrees.

In consideration of the above fact, by providing the recess or the step having a depth Lc (= 1 - 2 mm) only in the middle guide portion 15h2 to bring this guide portion closer to the tangent X, it is possible to smoothly feed the thicker and harder recording medium 4 without reducing the strength of the lower frame 15. At this time, since in most cases the thicker and harder recording medium 4 is a business card, an envelope or the like which is narrower than the postcard under the general specifications of the image forming system, there is no problem in practical use as long as the width of the stepped or recessed middle guide portion 15h2 is selected to be slightly larger than that of the postcard.

Further, regulating projections 15i projecting downward are formed on the outer surface of the lower frame 15 in areas outside the recording medium guide area. The regulating projections 15i each project from the guide surface of the lower frame for the recording medium 4 by about 1 mm. With this arrangement, even if the process cartridge B is lowered for some reason during the image forming operation, since the regulating projections 15i abut against a lower guide member 23 (Fig. 1) of the body 16 of the image forming system, the further lowering of the process cartridge can be prevented. Accordingly, a space of at least 1 mm is maintained between the lower guide member 23 and the lower guide surface of the lower frame 15 to provide a conveyance path for the recording medium 4, thereby conveying the recording medium without causing a jam. Furthermore, as shown in Fig. 1, a recess 15j is formed in the lower surface of the lower frame 15 so as not to interfere with the register roller 5c2. Therefore, when the process cartridge B is in the image forming System A is installed, since it is mounted near the register roller 5c2, the entire image forming system can be kept small.

(Assembly of the process cartridge)

Next, the assembly of the process cartridge having the above-described structure will be explained. In Fig. 29, toner leakage prevention seals S having a regular shape and made of Moltropren (flexible polyurethane manufactured by INOAC Incorp.) rubber for preventing leakage of toner are bonded to the ends of the developing means 12 and the cleaning means 13 and to the lower frame 15. The toner leakage prevention seals S may each have an irregular shape. Alternatively, the toner leakage prevention seals may be attached by forming recesses in portions (for attachment) of the seals and pouring a liquid material which becomes an elastomer when solidified into the recesses.

A sheet support member 12e1 to which the developing sleeve 12e is attached and a sheet support member 13a3 to which the cleaning sheet 13a is attached are attached to the lower frame 15 by pins 25a and 24b, respectively. According to the illustrated embodiment, as shown by broken lines in Fig. 29, the attachment surfaces of the sheet support members 12e1, 13a1 may be substantially parallel to each other so that the pins 24a, 24b may be driven from the same direction. Therefore, when a large number of process cartridges B are manufactured, the developing sheets 12e and the cleaning sheets 13a may be continuously attached by the pins by using an automatic device. Furthermore, the assemblability for the blades 12e, 13a can be improved by providing a space for a screwdriver, and the shape of a mold can be simplified by aligning the demolding direction for the mold, thereby achieving cost saving.

In doing so, the developing sheet 12e and the cleaning sheet 13a may not be attached by the pins (screws), but they may be attached to the lower frame 15 by adhesives 24c, 24d as shown in Fig. 30. Further, in this case, if adhesives can be applied from the same direction, the attachment of the developing sheet 12e and the cleaning sheet 13a can be carried out automatically and continuously by using an automatic device.

After the sheets 12e, 13a have been attached as described above, the developing sleeve 12d is attached to the lower frame 15. Then, the photosensitive drum 9 is attached to the lower frame 15. In the illustrated embodiment, guide members 25a, 25b are attached to surfaces (opposite the photosensitive drum) of the sheet support members 12e1 and 13a1, respectively, in areas outside the longitudinal image forming area C (Fig. 32) of the photosensitive drum 9 (in the illustrated embodiment, the guide members 25a, 25b are formed integrally with the lower frame 15). A distance between the guide members 25a and 25b is set to be larger than the outer diameter D of the photosensitive drum 9. Therefore, after the various parts such as the developing blade 12e, the cleaning blade 13a and the like are attached to the lower frame 15 as shown in Fig. 31, the photosensitive drum 9 can be finally attached to the lower frame while the two ends in the longitudinal direction (outside the image forming area) of the photosensitive drum are guided by the guide members 25a, 25b. Note that the photosensitive drum 9 is attached to the lower frame 15 while the cleaning blade 13a is slightly bent and/or the developing sleeve 12d is slightly retarded and rotated.

If the photosensitive drum 9 is first attached to the lower frame 15 and then the sheets 12e, 13a and the like are attached to the lower frame, there is a fear that the surface of the photosensitive drum 9 may be damaged during the attachment of the sheets. 12e, 13 and the like. Furthermore, during the assembly process, it is difficult or impossible to check the mounting position of the developing blade 12e and the cleaning blade 13a and to measure the contact pressures between the blades and the photosensitive drum. In addition, although a lubricant must be applied to the blades 12e, 13a to prevent an increase in the torque and/or the erection of the blade due to the intimate contact between the original blades 12e, 13a (in the state without toner) and the photosensitive drum 12d before the blades 12e, 13a are mounted on the lower frame 15, the lubricant is likely to drip off the blades during the mounting of the blades. However, according to the illustrated embodiment, since the photosensitive drum 9 is ultimately mounted on the lower frame, the above-described disadvantages can be avoided.

As described above, in the illustrated embodiment, it is possible to check the attachment positions of the developing agent 12 and the cleaning agent 13 in the state in which these agents 12, 13 are attached to the frame to prevent the image forming area of the photosensitive drum from being damaged or scratched during the assembly of the drum. Furthermore, since it is possible to apply the lubricant to the blades in the state in which these agents 12, 13 are attached to the frame, the dripping of the lubricant can be prevented, thereby preventing the occurrence of the increase in torque and/or the standing up of the blades due to the tight contact between the developing blade 12e and the developing sleeve 12d and the cleaning blade 13a and the photosensitive drum 9.

While in the illustrated embodiment the guide members 25a, 25b were formed integrally with the lower frame 15 as shown in Fig. 33, the projections 12e2, 13a2 may be formed integrally on the sheet support members, or other guide members may be formed on the sheet support members at both end portions in the longitudinal direction of the sheet support members outside the image. formation region of the photosensitive drum 9 so that the photosensitive drum 9 is guided by these projections or other guide members during assembly of the drum.

After the developing sleeve 12d, the developing blade 12e, the cleaning blade 13a and the photosensitive drum 9 are mounted on the lower frame 15 as described above, as shown in Fig. 34 (axonometric view) and Fig. 35 (sectional view), the support member 26 is installed to rotatably support one end of the photosensitive drum 9 and the developing sleeve 12d. The bearing member 26 is made of a wear-resistant material such as polyacetal, and includes a drum bearing portion 26a to be fitted to the photosensitive drum 9, a bearing portion 26b to be fitted to the outer surface of the developing sleeve 12d, and a D-shaped cut-out hole portion 26c to be fitted to a magnet 12c cut into a D-shape at one end. Alternatively, the sleeve bearing portion 26b may be fitted to the outside of the sleeve bearing 12i supporting the outer surface of the developing sleeve 12d, or it may be fitted between the sliding surfaces 15Q of the lower frame 15 fitted to the outer surface of the sliding bearing 12i.

Accordingly, when the drum support portion 26a is fitted on the end of the photosensitive drum 9, and when the end of the magnet 12c is fitted into the D-shaped cut-out portion 26c, and when the developing sleeve 12d is fitted therebetween into the sleeve support portion 26b, and when the support member 26 is fitted into the side of the lower frame 15 while sliding in the longitudinal direction of the drum, the photosensitive drum 9 and the developing sleeve 12d are rotatably supported. At this time, as shown in Fig. 34, the grounding contact 18a is fitted to the support member 26, and when the support member 26 is fitted into the side of the lower frame, the grounding contact 18a comes into contact with the aluminum drum core 9a of the photosensitive drum 9. contact (see Fig. 10). Further, the development bias contact 18b is also attached to the bearing member 26, and when the bearing member is attached to the development sleeve 12d, the bias contact 18b comes into contact with a conductive member 18d which contacts the inner surface of the development sleeve 12d.

By supporting the photosensitive drum 9 and the developing sleeve 12d by the single bearing member 26 in this way, it is possible to improve the positional relationship of the members 9, 12d and reduce the number of parts, thereby facilitating the assembly process and achieving cost reduction. Furthermore, since the positioning of the photosensitive drum 9 and the positioning of the developing sleeve 12d and the magnet 12c can be performed by a single member, it is possible to determine the positional relationship between the photosensitive drum 9 and the magnet 12c with high accuracy, with the result that it is possible to constantly maintain a magnetic force with respect to the surface of the photosensitive drum 9, thereby obtaining a high quality image. In addition, since the grounding contact 18a for grounding the photosensitive drum 9 and the developing bias contact 18b for applying the developing bias to the developing sleeve 12d are provided on the bearing member 26, compactness of the parts can be effectively achieved, thereby effectively making the process cartridge B small in size.

Further, by providing (on the support member 26) holding projections for positioning the process cartridge B in the image forming system when the process cartridge is installed in the image forming system, the positioning of the process cartridge B with respect to the image forming system can be accurately performed. As further seen from Figs. 5 and 6, an outwardly projecting U-shaped projection, that is, a drum shaft portion 26d (Fig. 20) is also formed on the support member 26. When the process cartridge B is installed in the body 16 of the image forming system, the drum shaft portion 26d is supported by a shaft support member 34 as described later. , thereby performing the positioning of the process cartridge B. In this way, since the process cartridge B is positioned by the bearing member 26 to directly support the photosensitive drum 9 when the cartridge is installed in the system body 16, the photosensitive drum 9 can be accurately positioned regardless of the manufacturing and/or assembly errors of the other parts.

Furthermore, as shown in Fig. 35, the other end of the magnet 12c is received in an inner cavity formed in the sleeve wheel 20k, and an outer diameter of the magnet 12c is selected to be slightly smaller than an inner diameter of the cavity. Therefore, the magnet 12c is held on the sleeve wheel 12k in the cavity with a clearance, and it is held in the cavity by its own weight in a lower position, or it is biased by the sheet support member 12e1 made of a magnetic material such as ZINKOTE (zinc-plated steel plate, manufactured by Shin Nippon Steel Incorp.) by a magnetic force of the magnet 12c. In this way, since the sleeve wheel 12k and the magnet 12k are fitted together with clearance, the friction torque between the magnet 12c and the rotating sleeve wheel 12k can be reduced, thereby reducing the torque as it affects the process cartridge.

Further, as shown in Fig. 31, the charge roller 10 is rotatably supported in the upper frame 14, and the shutter member 11b, the protective cover 22 and the toner supply mechanism 12b are also mounted on the upper frame 15. The opening 12a1 for supplying the toner from the toner container 12a to the developing sleeve 12d is closed by a cover film 28 (Fig. 36) having a pulling belt 27. Further, the lid member 12f is fixed on the upper frame, and thereafter, the toner is supplied to the toner container 12a through the filling opening 12a3, and then the filling opening 12a3 is closed by the lid 12a2, thereby sealing the toner container 12a.

In this case, as shown in Fig. 36, the release tape 27 of the cover film 28, which is adhered around the opening 12a1, extends from one end in the longitudinal direction (right end in Fig. 36) to the opening 12a1 to the other end in the longitudinal direction (left end in Fig. 36), and it is bent at the other end and further extends along a gripping portion 14f formed on the upper frame 14 and protrudes from the inside to the outside.

Next, the process cartridge B is assembled by connecting the upper and lower frames 14, 15 to each other via the above-described pawls and locking holes or recesses. In this case, as shown in Fig. 37, the trigger tape 27 protrudes between the gripping portion 14f of the upper frame 14 and a gripping portion 15k of the lower frame 15. Therefore, when a new process cartridge B is used, the operator pulls a projecting portion of the peel tape 27 projecting between the gripping portions 14f, 15k to peel the peel tape from the cover film 28 so as to open the opening 12a1, thereby allowing the movement of the toner in the toner container 12a toward the developing sleeve 12d. Thereafter, the process cartridge is installed in the image forming system A.

As described above, the protrusion of the peel tape 27 between the gripping portions 14f, 15k of the upper and lower frames 14, 15 allows the peel tape 27 to easily protrude from the process cartridge when assembling the upper and lower frames 14, 15. The gripping portions 14f, 15k are used when the process cartridge B is installed in the image forming system. Therefore, if the operator forgets to remove the peel tape 27 before installing the process cartridge in the image forming system, he must recognize the presence of the peel tape 27 not yet removed because he must grip the gripping portions when installing the process cartridge. Furthermore, if the color of the trigger tape 27 is clearly distinguished from the color of the frames 14, 15 (for example, if the frames are black, a white or yellow trigger tape 27 is used), the visibility is improved, thereby making failure to remove the trigger tape less frequent.

If, for example, a U-shaped rib for temporarily holding the trigger band 27 on the handle portion 14f of the upper frame 14, it is possible to easily and securely protrude the take-up tape 27 at a predetermined position during the connection of the upper and lower frames 14, 15. At this time, when the process cartridge B is assembled by connecting the upper and lower frames 14, 15 together, since the recess 15j for receiving the register roller 5c2 is formed in the outer surface of the lower frame 15 as shown in Fig. 38, the operator can easily grip the process cartridge B by inserting his fingers into the recess 15j. Further, in the illustrated embodiment, as shown in Fig. 6, slippage prevention ribs 14i are formed on the process cartridge B so that when the operator grasps the process cartridge, he can easily rest his fingers on the ribs. Furthermore, since the recess for receiving (preventing contact) the register roller 5c2 is formed in the lower frame 15 of the process cartridge, it is possible to make the image forming system even smaller.

Furthermore, as shown in Fig. 6, since the recess 15j is formed along and near the locking claws 14a and the locking holes 15b through which the upper and lower frames 14, 15 are connected to each other, when the operator grips the process cartridge B by resting his fingers in the recess 15j, the operator's gripping force acts in the locking direction, thereby securely locking the locking claws 14a and the locking holes 15b.

The assembly and shipping line for the process cartridge B will now be described with reference to Fig. 39A. As shown, the various parts are assembled in the lower frame 15, and then the lower frame in which the various parts are installed is checked (for example, the positional relationship between the photosensitive drum 9 and the developing sleeve 12d is checked). Then, the lower frame 15 is assembled with the upper frame 14 within which the parts such as the charging roller 10 are installed, thereby forming the process cartridge B. Thereafter, a Overall inspection of process cartridge B is carried out, and then the process cartridge is shipped. Therefore, the assembly and shipping line is very simple.

(Assembling the cartridge)

Next, the construction for installing the process cartridge B into the image forming system A will be explained.

As shown in Fig. 40, a loading member 29 having an insertion window 29a conforming to the contour of the process cartridge B is provided on the upper opening/closing cover 19 of the image forming system A. The process cartridge B is inserted into the image forming system via the insertion window 29a by gripping the grip portions 14f, 15k. In this case, a guide rib 31 formed on the process cartridge B is guided by a guide groove (not designated) formed in the cover 19, and a lower portion of the process cartridge is guided with a guide plate 32 having a hook at its free end.

40, a projection 30 for preventing erroneous assembly is formed on the process cartridge B, and the insertion window 29a has a recess 29b for receiving the projection 30. As shown in FIGS. 40 and 41, the position of the projection 30 is different depending on a particular process cartridge containing the toner having the developing property suitable for a particular image forming system A (i.e., different for each process cartridge), so that even if an attempt is made to mount a process cartridge containing a toner having a different developing property, it cannot be mounted in the image forming system because the projection 30 does not match with the insertion window 29a of that image forming system. Therefore, incorrect installation of the process cartridge B can be prevented, thereby preventing the formation of a poorly recognizable image due to the toner having a different development property. It is also possible to prevent the erroneous installation of a process cartridge containing a different type of photosensitive drum and having a different development sensitivity. Furthermore, since the recess 29b and the projection 30 are located on this side, when the process cartridge is installed, if the operator mistakenly attempts to install the process cartridge into the image forming system, the operator can easily recognize the fact that the projection 30 is blocked by the filling member 29. Therefore, the possibility that the operator forcibly installs the process cartridge into the image forming system, thereby damaging the process cartridge B and/or the image forming system A, can be avoided as compared with the conventional case.

After the process cartridge B is inserted into the insertion window 29a of the opening/closing cover 19, when the cover 19 is closed, the rotational axis 12f of the photosensitive drum 9 projecting from one side of the upper and lower frames 14, 15 is supported by an axis support member 33 (Fig. 40) via a bearing 46, and the rotational axis 12d2 of the developing sleeve 12d projecting from one side of the upper and lower frames 14, 15 is supported by the axis support member 33 via a sliding bearing 46b and a bearing 46c (Fig. 35). On the other hand, the drum shaft portion 26d (Fig. 35) of the support member 26 attached to the other end of the photosensitive drum 9 is supported by a shaft support member 34 shown in Fig. 42.

In this case, the protective cover 22 is rotated to release the photosensitive drum 9, with the result that the photosensitive drum 9 comes into contact with the transfer roller of the image forming system A. Further, the drum grounding contact 18a which contacts the photosensitive drum 9, the developing bias contact 18b which contacts the developing sleeve 12d, and the charging bias contact 18c which contacts the charging roller 10 are provided on the process cartridge B so that these contacts protrude from the lower surface of the lower frame 15, and that these contacts 18a, 18b, 18c are in pressure contact with the drum grounding contact pin 35a, the developing bias contact pin 35b, and the loading bias contact pin 35c, respectively (Fig. 42).

As shown in Fig. 42, these contact pins 35a, 35b, 35c are arranged such that the drum grounding contact pin 35a and the charging leader contact pin 35c are provided on a downstream side of the transfer roller 6 in the conveying direction of the recording medium, and the developing leader contact pin 35b is provided on an upstream side of the transfer roller 6 in the conveying direction of the recording medium. Accordingly, as shown in Fig. 43, the contacts 18a, 18b, 18c provided on the process cartridge B are similarly arranged such that the drum grounding contact 18a and the charging bias contact 18c are arranged on a downstream side of the photosensitive drum 9 in the conveying direction of the recording medium, and the developing bias contact 18c is arranged on an upstream side of the photosensitive drum 9 in the conveying direction of the recording medium.

The arrangement of the electric contacts of the process cartridge B will now be explained with reference to Fig. 51. Fig. 51 is a schematic plan view showing the positional relationship between the photosensitive drum 9 and the electric contacts 18a, 18b, 18c.

As shown in Fig. 51, the contacts 18a, 18b, 18c are arranged at the end of the photosensitive drum 9 opposite to the end at which the flange gear 9c is arranged in the longitudinal direction of the drum. The development bias contact 18b is arranged at one side of the photosensitive drum 9 (that is, at the side where the developing sleeve 12d is arranged), and the drum grounding contact 18a and the charging bias contact 18c are arranged at the other side of the photosensitive drum 9 (where the cleaning means 13 is arranged). The drum grounding contact 18a and the charging bias contact 18c are arranged substantially on a straight line. Further, the development bias contact 18b is arranged slightly outward with respect to the positions of the drum grounding contact 18a and the charging bias contact 18c in the longitudinal direction of the photosensitive drum 9. The drum grounding contact 18a, the developing bias contact 18b and the charging bias contact 18c are spaced from the outer peripheral surface of the photosensitive drum 9 in a stepped manner in this order (that is, a distance between the contact 18a and the drum is the smallest, and a distance between the contact 18c and the drum is the largest). Further, an area of the developing bias contact 18b is larger than an area of the drum grounding contact 18a and an area of the charging bias contact 18c. Further, the developing bias contact 18b, the drum grounding contact 18a and the charging bias contact 18c are arranged outward from a position where the arm portions 18a3 of the drum grounding contact 18a are in contact with the inner surface of the photosensitive drum 9 in the longitudinal direction of the photosensitive drum 9.

As described above, by arranging the electrical contacts between the process cartridge (which may be incorporated in the image forming system) and the image forming system on the positioning and stopping side of the process cartridge, it is possible to improve the positional accuracy between the contacts of the process cartridge and the contact pins of the image forming system, thereby preventing poor electrical connection, and by arranging the contacts on the non-driven side of the cartridge, it is possible to make the formation of the contact pins of the image forming system simple and small in size.

Furthermore, since the contacts of the process cartridge are arranged on the inner side of the periphery of the frames of the process cartridge, it is possible to prevent foreign matter from adhering to the contacts, and thus it is possible to prevent corrosion of the contacts; and further, it is possible to prevent deformation of the contacts due to an external force. Furthermore, since the development bias Contact 18b is arranged on the side of the developing agent 12, and since the drum grounding contact 18a and the charging bias contact 18c are arranged on the side of the cleaning agent 13, the arrangement of the electrodes in the process cartridge can be simplified, thereby making the process cartridge small in size.

Now, the dimensions of various parts in the illustrated embodiment will be listed below. However, it should be noted that these dimensions are only an example and the present invention is not limited to this example:

(1) Distance (X1) between the photosensitive drum 9 and the drum grounding contact 18a approximately 6.0 mm

(2) Distance (X2) between the photosensitive drum 9 and the charging bias contact 18c approx. 18.9 mm

(3) Distance (X3) between the photosensitive drum 9 and the developing leader contact 18b approximately 13.5 mm

(4) Width (Y1) of the charging bias contact 18c approx. 4.9 mm

(5) Length (Y2) of the charging bias contact 18c approx. 6.5 mm

(6) Width (Y3) of drum earthing contact 18a approx. 5.2 mm

(7) Length (Y4) of drum earthing contact 18a approx. 5.0 mm

(8) Width (Y5) of the development bias contact 18b approx. 7.2 mm

(9) Length (Y6) of the development bias contact 18b approx. 8.0 mm

(10) Diameter (Z1) of the flange wheel 9c approx. 28.6 mm

(11) Diameter (Z2) of gear 9i approx. 26.1 mm

(12) Width (Z3) of the flange wheel 9c approx. 6.7 mm

(13) Width (Z3) of gear 9i approx. 4.3 mm

(14) Number of teeth of the flange wheel 9c 33; and

(15) Number of teeth of gear 9i 31.

The flange gear 9c and the gear 9i will now be explained. The gears 9c, 9i are helical gears. When the driving force from the image forming system is transmitted to the flange gear 9c, the photosensitive drum 9, which is installed in the lower frame 15 with clearance, is subjected to the pressing force which pushes it toward the flange gear 9c, thereby positioning the drum on the side of the lower frame 15.

The gear 9c is used with a process cartridge containing the magnetic toner to form a black image. When the process cartridge forming the black image is installed in the image forming system, the gear 9c meshes with a gear of the image forming system to receive the driving force to rotate the photosensitive drum 9, and meshes with a gear of the developing sleeve 12d to rotate the latter. The gear 9i meshes with a gear connected to the transfer roller of the image forming system to rotate the transfer roller. In this case, the rotational load does not even act on the transfer roller 6.

Optionally, the gear 9i is used with a color image forming cartridge containing the non-magnetic toner. When the color image forming cartridge is installed in the image forming system, the gear 9c meshes with the gear of the image forming system to receive the driving force to rotate the photosensitive drum 9. On the other hand, the gear 9i meshes with the gear connected to the transfer roller 6 of the image forming system to rotate the transfer roller, and meshes with the gear of the developing sleeve 12d for the non-magnetic toner to rotate the latter. The flange gear 9c has a diameter larger than that of the gear 9i, a width larger than that of the gear 9i, and a number of teeth which is larger than that of the gear 9i. Therefore, even if a larger load is applied to the gear 9c, the gear 9c can receive the driving force to rotate the photosensitive drum 9 with greater certainty, and can transmit the larger driving force to the magnetic toner developing sleeve 12d to rotate the latter with greater certainty.

As shown in Fig. 43, each of the contact pins 35a - 35c is held in a corresponding holding cover 36 in such a way that it can be slid in the holding cover but cannot be removed from the holding cover. Each contact pin 35a - 35c is electrically connected to a circuit printed on an electrical substrate 37 on which the holding covers 36 are mounted, via a corresponding conductive compression spring 38. Meanwhile, the loading bias contact 18c intended to be applied to the contact pin 35c has the arcuate curvature near the pivot axis 19b of the upper opening/closing cover 19, so that the opening/closing cover 19 on which the process cartridge B is mounted is rotated about the pivot axis 19b in a direction shown by the arrow R to close the cover, whereby the loading bias contact 18c closest to the pivot axis 19b (i.e., having the maximum stroke) effectively closes the Contact pin 35c can touch.

(Positioning)

When the process cartridge B is installed and the opening/closing cover 19 is closed, the positioning is effected so that a distance between the photosensitive drum 9 and the lens unit 1c and a distance between the photosensitive drum 9 and the original glass carrier 1a are kept constant. This positioning will now be explained.

As shown in Fig. 8, positioning projections 15m are formed on the lower frame 15 on which the photosensitive drum 9 is mounted, in the vicinity of both ends of the frame in the longitudinal direction. As shown in Fig. 5, when the upper and lower frames 14, 15 are joined together, these projections 15m project upward through holes 14g formed in the upper frame 14.

Further, as shown in Fig. 44, the lens unit 1c containing therein the lens assembly 1c2 for reading the original 2 is attached to the upper opening/closing cover 19 (to which the process cartridge B is attached) via a pivot pin 1c3 for easy pivoting about the pivot pin, and is biased downward (Fig. 44) by a compression spring 39. Therefore, when the process cartridge B is attached to the upper cover 19 and the latter is closed as shown in Fig. 44, the lower surface of the lens unit 1c abuts against the positioning projections 15m of the process cartridge B. As a result, when the process cartridge B is installed in the image forming system A, the distance between the lens array 1c2 in the lens unit 1c and the photosensitive drum 9 mounted on the lower frame 15 is precisely determined so that the light image optically read from the original 2 can be accurately projected onto the photosensitive drum 9 via the lens array 1c2.

Further, as shown in Fig. 45, positioning projections 40 are provided in the lens unit 1c, which positioning projections can slightly project upward from the top cover 19 through holes 19c formed in the top cover. As shown in Fig. 46, the positioning projections 40 slightly project at both ends in the longitudinal direction of an original reading slot Z (Figs. 1 and 46). Therefore, when the process cartridge B is attached to the top cover 19 and the latter is closed and then the image forming operation is started as described above, since the lower surface of the lens unit 1c abuts on the positioning projections 15m, the original glass carrier 1a is displaced while sliding on the positioning pins 40. As a result, a gap is created between the original 2, which lies on the original glass carrier 1a, and the photosensitive drum 9 mounted on the lower frame 15 is always kept constant, whereby the light reflected from the original 2 is correctly projected onto the photosensitive drum 9. Furthermore, since the information written on the original 2 can be optically read accurately and since the exposure of the photosensitive drum 9 can be accurately performed, it is possible to obtain a high quality image.

(Drive transmission)

Next, the power transmission to the photosensitive drum 9 in the process cartridge B incorporated in the image forming system A will be explained.

When the process cartridge B is installed in the image forming system A, the rotation axis 9f of the photosensitive drum 9 is supported by the axis support member 33 of the image forming system as described above. As shown in Fig. 47, the axis support member 33 includes a support portion 33a for the drum rotation axis 9f and a stopper portion 33b for the rotation axis 12d2 of the developing sleeve 12d. An overlap portion 33c having a predetermined amount L of overhang (1.8 mm in the illustrated embodiment) is formed on the support portion 33a, thereby preventing the rotation axis 9f of the drum from sliding upward. Further, when the rotation shaft 9f of the drum is supported by the bearing portion 33a, the rotation shaft 12d2 of the developing sleeve abuts against the stopper portion 33b, thereby preventing the rotation shaft 12d2 from falling downward. Further, when the upper opening/closing cover 19 is closed, the positioning projections 15p of the lower frame 15 protruding from the upper frame 14 of the process cartridge B abut against a stopper portion 19c of the opening/closing cover 19.

Accordingly, when the driving force is transmitted to the flange gear 9c of the photosensitive drum 9 by driving the driving gear 41 of the image forming system which meshes with the flange gear, the process cartridge B is subjected to a reaction force which acts to process cartridge B about the drum rotation axis 9f in a direction shown by arrow i in Fig. 47. However, since the rotation axis 12d2 of the developing sleeve abuts against the stopper portion 33b and the positioning projections 15p of the lower frame 15 projecting from the upper frame 14 abut against the stopper portion 19c of the upper cover, the rotation of the process cartridge B is prevented.

Although, as described above, the lower surface of the lower frame 15 serves as the guide for the recording medium 4, since the lower frame is positioned by abutting against the body of the image forming system as described above, the positional relationship between the photosensitive drum 9, the transfer roller 6 and the guide portions 15h1, 15h2 for the recording medium 4 is maintained with high accuracy, whereby the feeding of the recording medium and the image transfer are carried out with high accuracy.

During the transmission of the driving force, the developing sleeve 12d is biased downward not only by the reaction force in the rotational direction acting on the process cartridge B, but also by a reaction force generated when the driving force is transmitted from the flange gear 9c to the sleeve gear 12j. In this case, if the rotation axis 12d2 of the developing sleeve does not abut against the stopper portion 33b, the developing sleeve 12d will always be biased downward during the image forming process. As a result, there is a fear that the developing sleeve 12d will be displaced downward and/or the lower frame 15 on which the developing sleeve 12d is mounted will be deformed. However, since in the illustrated embodiment the rotation axis 12d2 of the development sleeve rests perfectly against the stop section 33b, the inconvenience described above does not occur.

In this case, as shown in Fig. 20, the developing sleeve 12d is biased against the photosensitive drum 9 by the springs 12j via the sleeve bearings 12i. In this case, the arrangement as shown in Fig. 48 is adopted to facilitate the sliding movement of the sleeve bearings 12i. Note that a bearing 12m for supporting the rotational axis 12d2 of the developing sleeve is held in a bearing holder 12n in such a manner that the bearing 12m can slide along a slot 12n1 formed in the bearing holder. With this arrangement, as shown in Fig. 49, the bearing holder 12n abuts against and is supported by the stopper portion 33b of the axis support member 33; in this state, the bearing 12m can slide along the slot 12nl in directions shown by the arrow. In the illustrated embodiment, an inclination angle θ (Fig. 47) of the stopper portion 33b is selected to have a value of about 40°.

Further, the developing sleeve 12d may not be supported by the sleeve rotation axis. For example, as shown in Figs. 52A and 52B, it may be supported at both end portions thereof by sleeve bearings 52, the lower ends of which are supported by the lower frame 15, which in turn is supported by the receiving portions 53 formed in the image forming system.

Further, in the illustrated embodiment, the flange gear 9c of the photosensitive drum 9 meshes with the drive gear 41 for transmitting the driving force to the flange gear in such a manner that, as shown in Fig. 47, a line connecting a fulcrum of the flange gear 9c and a fulcrum of the drive gear 41 is offset from a vertical line passing through the rotation axis of the flange gear 9c in a counterclockwise direction by a small angle α (about 1° in the illustrated embodiment), whereby a direction F of driving force transmission from the drive gear 41 to the flange gear 9c is upward. Although, in general, the sliding of the process cartridge can be prevented by a downward force generated by forming an angle α is set to a value of 20º or more, such an angle α is set to approximately 1º in the illustrated embodiment.

By setting the above-described α to about 1°, when the opening/closing cover 19 is opened in a direction shown by the arrow j to remove the process cartridge B, the flange gear 9c is not blocked by the drive gear 41 and can therefore be smoothly disengaged from the drive gear 41. Furthermore, when the direction F of the driving force transmission is directed upward as described above, the rotation axis 9f of the photosensitive drum 9 is pushed upward and therefore tends to be disengaged from the drum support portion 33a. However, since in the illustrated embodiment the overlapping section 33c is formed on the bearing section 33a, the drum rotation axis 9f is not disengaged from the drum bearing section 33a.

(Recycling)

The process cartridge having the above-described structure allows recycling. Note that the used process cartridge(s) can be collected from the market and its parts can be reused to form a new process cartridge. Such recycling will now be explained. Generally, the used process cartridge has been discarded or thrown away in the past. However, the process cartridge B according to the illustrated embodiment can be collected from the market after the toner in the toner container has been used up in order to protect the earth's resources and the environment. Then, the collected process cartridge is disassembled into the upper and lower frames 14, 15, which are cleaned. Thereafter, reusable parts and new parts are mounted on the upper frame 14 or the lower frame 15 as required, and then new toner is filled into the toner container 12a. In this way, a new process cartridge is obtained.

In particular, by making the connections between the locking claws 14a and the locking openings 15a, the locking claws 14a and the locking projection 15b, the locking claw 14c and the locking opening 15d, and the locking claw 15c and the locking hole 14d (Figs. 4, 8 and 9) connecting the upper and lower frames 14, 15 are released, the upper and lower frames 14, 15 can be easily separated from each other. Such disassembly operation can be easily carried out by, for example, setting the used process cartridge B on a disassembly tool 42 by pressing the locking claw 14a by means of a pusher 42a as shown in Fig. 50. Even when the disassembly tool is not used, the process cartridge can be disassembled by pressing the locking claws 14a, 14c, 15c.

After the upper frame and the lower frame 15 are separated from each other as described above (Figs. 8 and 9), the frames are cleaned by removing the toner waste adhering to them or remaining in the cartridge by an air jet method. In this case, a relatively large amount of toner waste adheres to the photosensitive drum 9, developing sleeve 12d and/or the cleaning agent 13 since they directly contact the toner. On the other hand, toner waste does not adhere or adheres to a small extent to the charging roller 10 since it does not directly contact the toner. Accordingly, the charging roller 10 can be cleaned more easily than the photosensitive drum 9, developing sleeve 12d and the like. In this connection, since, according to the embodiment shown, the charging roller 10 is mounted on the upper frame 14, in contrast to the lower frame 15 on which the photosensitive drum 9, the developing sleeve 12d and the cleaning agent 13 are mounted, the upper frame 14, which is separated from the lower frame 15, can be easily cleaned.

In the disassembling and cleaning line, as shown in Fig. 39B, first, the upper and lower frames 14, 15 are separated from each other as described above. Then, the upper frame 14 and the lower frame 15 are disassembled and cleaned independently of each other. Thereafter, as for the upper frame 14, the loading roller 10 is separated from the upper frame and cleaned; and as for the As for the lower frame 15, the photosensitive drum 9, the developing sleeve 12d, the developing blade 12e, the cleaning blade 13a and the like are separated from the lower frame and cleaned. Therefore, the disassembly and cleaning line is very simple.

After the toner has been removed, as shown in Fig. 9, the opening 12a1 is closed again by a new cover film 28, and the new toner is supplied into the toner container 12a through the toner filling opening 12a3 formed in the side surface of the toner container 12a, and then the filling opening 12a3 is closed by the lid 12a2. Then, the upper frame 14 and the lower frame 15 are reconnected by restoring the connections between the locking claws 14a and the locking holes 15a, the locking claws 14a and the locking projection 15b, the locking claw 14c and the locking hole 15d, and the locking claw 15c and the locking hole 14b, thereby restoring the process cartridge to a usable state.

At this time, when the upper and lower frames 14, 15 are connected to each other, if the same process cartridge is recycled many times, there is a fear that the locking forces between the locking claws and the locking holes become weaker even though the locking claws 14a and the locking holes 15a, the locking claws 14a and the locking projection 15b and the like are locked to each other. To cope with this, in the illustrated embodiment, screw holes are formed in the frame near its four corners. It should be noted that the through-screw holes are formed in the fitting recesses 14d and in the fitting projections 14e of the upper frame 14 (Fig. 8), or in the fitting projections 15e (which are to be inserted into the recesses 14d) and in the fitting recesses 15f (which are to be placed on the projections 14e) of the lower frame 15. Therefore, even if the locking force becomes weaker due to the locking claws, after the upper and lower frames 14, 15 are connected to each other, have been connected and the fitting projections and the fitting recesses have been fitted together, the upper and lower frames 14, 15 are securely connected to one another by screwing the screws into the corresponding screw holes.

Image formation process

Next, the image forming operation by the image forming system A in which the process cartridge B is mounted will be explained.

First, the original 2 is placed on the original glass carrier 1a shown in Fig. 1. Then, when the copy start button A3 is depressed, the light source 1c1 is turned on, and the original glass carrier 1a is reciprocated on the image forming system in the left and right direction in Fig. 1 to optically read the information written on the original. On the other hand, in accordance with the reading of the original, the sheet feed roller 5a and the pair of register rollers 5c1, 5c2 are rotated to feed the recording medium 4 to the image forming station. The photosensitive drum 9 is rotated in the direction d in Fig. 1 in time with the conveyance by the pair of register rollers 5c1, 5c2, and is uniformly charged by the charging means 10. Then, the light image read by the reading means 1 is exposed to the photosensitive drum 9 via the developing means 11, thereby forming the latent image on the photosensitive drum 9.

At the same time that the latent image is formed, the developing agent 12 of the process cartridge B is activated to drive the toner supply mechanism 12b, whereby the toner is fed out from the toner container 12a to the developing sleeve 12d and forms the toner layer on the rotating developing sleeve 12d. Then, by applying a voltage to the developing sleeve 12d having the same charge polarity and potential as the photosensitive drum 9, the latent image on the photosensitive drum 9 is visualized as the toner image. In the illustrated In the embodiment shown, the voltage of about 1.2 kVpp, 1590 Hz (square wave) is applied to the developing sleeve 12d. The recording medium 4 is conveyed between the photosensitive drum 9 and the transfer roller 6. By applying a voltage having the polarity opposite to that of the toner to the transfer roller 6, the toner image on the photosensitive drum 9 is transferred to the recording medium 4. In the embodiment shown, the transfer roller 6 is made of foam EPDM having a volume resistivity of about 10⁹ Ωcm and an outer diameter of about 20 mm, and the voltage of -3.5 kV is applied to the transfer roller as a transfer voltage.

After the toner image is transferred to the recording medium, the photosensitive drum 9 continues to rotate in the direction d. In the meantime, the residual toner remaining on the photosensitive drum 9 is removed by the cleaning blade 13a, and the removed toner is collected in the waste toner container 13c via the peeling blade 13b. On the other hand, the recording medium 4 onto which the toner image has been transferred is conveyed by the conveying belt 5d to the fixing means 7, where the toner image is permanently fixed on the recording medium 4 by heat and pressure. Then, the recording medium is ejected by the pair of ejection rollers 5f1, 5f2. In this way, the information on the original is recorded on the recording medium.

Other variants will be explained below.

While in the first embodiment described above, an example was explained in which the developing blade 12e and the cleaning blade 13a are attached to the frame via pins 24a, 24b as shown in Fig. 53, when the developing blade 12e and the cleaning blade 13a are attached to the lower frame 15 by forcibly fitting fitting projections 43a, 43b provided at both ends in the longitudinal direction of the developing blade 12e and the cleaning blade 13e into corresponding fitting recesses 44a, 44b, which fitting projections Recesses are formed in the body 16 of the image forming system, pin holes 45 for receiving the pins for attaching the sheets 12e, 13a may be formed in the vicinity of the fitting projections 43a, 43b, and corresponding pin holes 45 may be formed in the body 16 of the image forming system (instead of the fitting projections 43a, 43b, half-punches or circular projections may be used).

In this embodiment, when the fitting connections between the blades 12e, 13a and the lower frame are loosened by repeated recycling of the process cartridge B, the blades 12e, 13a can be securely attached to the lower frame by the pins.

Furthermore, while in the first embodiment, as shown in Fig. 29, an example has been explained in which the outer diameter D of the photosensitive drum 9 is smaller than the distance L between the drum guide members 25a, 25b to enable the photosensitive drum 9 to be finally mounted on the lower frame 15, as shown in Fig. 54, even when the photosensitive drum 9 is installed in the upper frame 14, the outer diameter D of the photosensitive drum 9 may be smaller than the distance L between the drum guide members 25a, 25b so that the photosensitive drum can be finally installed in the upper frame, thereby preventing the photosensitive drum 9 from being damaged, as in the first embodiment. Here, in Fig. 54, the elements or parts having the same function as the in the first embodiment variant are designated by the same reference numerals. Furthermore, the upper and lower frames 14, 15 are connected by the locking projections 47a and the locking openings 47b, as well as by these being secured by pins 48.

Furthermore, while in the first embodiment, as shown in Fig. 35, the photosensitive drum 9 and the developing sleeve 12d have been supported by the support member 26, if the flange wheel 9c is arranged at one end of the photosensitive drum 9, and the transfer roller gear 49 is provided at the other end of the photosensitive drum 9, a structure as shown in Fig. 55 may be adopted. Here, in Fig. 55, too, the elements having the same function as those in the first embodiment are designated by the same reference numerals.

Specifically, in Fig. 55, the flange wheel 9c and the transfer roller wheel 49 are respectively fixed to the two ends of the photosensitive drum 9 by a press fit or the like, the positioning of the drum is carried out by rotatably supporting a central hub 49a of the transfer roller wheel 49 by the bearing portion 33a of the bearing member 26. In this case, in order to ground the photosensitive drum 9, a drum grounding plate 50 having a central L-shaped contact portion is connected to and in contact with the inner surface of the drum, and a drum grounding shaft 51 passing through a central hole in the transfer roller wheel 49 is always in contact with the drum grounding plate 50. The drum grounding shaft 51 is made of a conductive metal such as stainless steel, and the drum grounding plate 50 is also made of a conductive metal such as bronze phosphate, stainless steel or the like. When the process cartridge B is installed in the image forming system A, a head 51a of the drum grounding shaft 51 is supported by the bearing member 26. In this case, the head 51a of the drum grounding shaft 51 comes into contact with the drum grounding contact pin of the image forming system to ground the photosensitive drum. Also in this case, as in the first embodiment, the positioning accuracy between the photosensitive drum 9 and the developing sleeve 12d can be improved by using a single bearing member 26.

Furthermore, the process cartridge B according to the present invention can be used not only to form a single-color image as described above, but also to form a multi-color image (two-color image, three-color image or full-color image) by providing a plurality of developing means 12. Further, the developing method may be of the two-component magnetic brush type of cascade development type, touch-down development type or haze development type. While in the first embodiment the charging means was of the so-called contact charging type, in addition thereto, for example, other conventional charging methods may be used in which tungsten wires and metal shields made of aluminum are provided on the three walls, and in which positive or negative ions generated by a high voltage applied to the tungsten wires are displaced onto the surface of the photosensitive drum 9, thereby uniformly charging the surface of the photosensitive drum 9.

The contact charge can be, for example, of the sheet type (charging sheet), of the pad type, of the block type, of the rod type or of the wire type, as well as of the roller type described above. Furthermore, the cleaning agent for removing the toner residues remaining on the photosensitive drum 9 can be of the so-called brush type or of the magnetic brush type, as well as of the sheet type.

Further, the process cartridge B comprises an image bearing member (e.g., an electrophotographic photosensitive member) and at least one processing means. Therefore, as in the above-described structure, the process cartridge may integrally contain in its interior the image forming member and the charging means as a unit which may be removably mounted in the image forming system; or it may integrally contain in its interior the image forming member and the developing means as a unit which may be removably mounted in the image forming system; or it may integrally contain in its interior the image bearing member and the cleaning means as a unit which may be removably mounted in the image forming system; or it may integrally contain in its interior the image bearing member and two or more processing means as a unit which may be removably mounted in the image forming system. It should be noted that the process cartridge contains the charging agent, the developing agent or the cleaning agent and the electrophotographic photosensitive member as a unit which can be removably mounted in the image forming system; or that it integrally contains in its interior at least one of the charging means, the developing means and the cleaning means and the electrophotographic photosensitive member as a unit which are removably mounted in the image forming system; or that it integrally contains in its interior the developing means and the electrophotographic photosensitive member as a unit which can be removably mounted in the image forming system.

Furthermore, while in the illustrated embodiment the image forming system was the electrophotographic copying machine, the present invention is not limited to the copying machine, but it can also be applied to various other image forming systems such as a laser printer, a facsimile machine, a word processor and the like.

Now, the above-described driving force transmission to the photosensitive drum 9 will be further described in more detail. As shown in Fig. 56, the driving force from the driving motor 54 mounted on the image forming system body 16 is transmitted to a driving gear G6 via a gear chain G1 - G5, and from the driving gear G6 to the flange gear 9c meshing with the driving gear, thereby rotating the photosensitive drum 9. Further, the driving force of the driving motor 54 is transmitted from the gear G4 to the gear chain G7 - G11, thereby rotating the sheet feed roller 5a. Furthermore, the driving force from the drive motor 54 is transmitted from the gear G1 to the drive roller 7a of the fixing means 7 via the gears G12, G13.

Further, as shown in Figs. 57 and 58, the flange gear (first gear) 9c and the gear (second gear) 9i are integrally formed, and parts of the gears 9c, 9i protrude from an opening 15g formed in the lower frame 15. When the process cartridge B is installed in the image forming system A as shown in Fig. 59, the drive gear G6 meshes with the flange gear 9c of the photosensitive drum 9, and the gear 9i integral with the gear 9c meshes with the gear 55 of the transfer roller 6. Incidentally, in Fig. 59, the parts of the image forming system are shown by the solid line, and the parts of the process cartridge are shown by the broken lines.

The number of teeth of the gear 9c is different from that of the gear 9i so that the rotational speed of the developing sleeve 12d when the black image forming cartridge containing the magnetic toner is used is different from the rotational speed of the developing sleeve when the color image forming cartridge containing the non-magnetic toner is used. Note that when the black image forming cartridge containing the magnetic toner is installed in the image forming system as shown in Fig. 60A, the flange gear 9c meshes with the sleeve gear 12k of the developing sleeve 12d. On the other hand, when the color image forming cartridge containing the non-magnetic toner is installed in the image forming system as shown in Fig. 60B, the gear 9i meshes with the sleeve gear 12k of the developing sleeve 12d to rotate the developing sleeve.

As described above, since the gear 9c has the larger diameter and the larger width than the gear 9i, and since it has a number of teeth that is larger than that of the gear 9i, even if a larger load is applied to the gear 9c, the gear 9c can surely receive the driving force to rotate the photosensitive drum 9, and transmits the larger driving force to the magnetic toner developing sleeve 12d, thereby surely rotating the developing sleeve 12d.

Next, when the developing blade 12e and the cleaning blade 13a are forcefully inserted into the fitting portions 44a, 44b of the image forming system body 16 as shown in Fig. 53, preferred embodiments of a cleaning blade will be explained. Although the cleaning blade 13a will be described below, the development sheet 12e can be considered the same.

Fig. 61 is an axonometric view showing a cleaning blade 13a and a fitting portion 44b, and Figs. 62 and 63 are plan views thereof. As shown in Figs. 61 to 63, a tapered portion 43b1 is formed by obliquely cutting off a lower portion of a fitting projection 43b formed at one end in the longitudinal direction of the blade supporting member 13a1, and a tapered portion 44b1 is formed by obliquely cutting off an upper portion of the fitting portion 44b of the image forming system body 16. Therefore, when the fitting projection 43b is fitted onto the fitting portion 44b by engaging the tapered portions 43b1, 44b1, respectively, the projection 43b can be smoothly inserted into the fitting portion 44b.

At this time, as shown in Fig. 63, when the fitting projection 43b is inserted into the fitting portion 44b, a lower end 43b2 of the projection 43b abuts against a lower end 44b2 of the fitting portion 43b, thereby regulating the amount of insertion of the cleaning blade 13a. Therefore, when the tapered portion 43b1 is formed on the fitting projection 43b, it is preferable that the lower ends 43b2 are omitted.

Furthermore, although the fitting projection 43b is forcibly inserted into the fitting portion 44b as described above when fitting the blade support member 13a1, in the case of the automatic assembling operation as shown in Fig. 64, the lower frame 15 is pulled by an appropriate tool (not shown) in a direction shown by the arrow to elastically deform it so as to increase the distance between the fitting portions 44b, and then, as shown in Fig. 65, the blade support member 13a1 is inserted between the fitting portions 44b. In this case, as described above, the fitting operation can be smoothly performed due to the presence of the tapered portions 43b1, 44b1. Then, when the tool is to be released as shown in Fig. 66, the deformation of the lower frame 15 is elastically restored, thereby inserting the fitting projections 43b into the fitting portions 44b. Further, the fitting portions 44b are pressed in directions shown by the arrows in Fig. 66, thereby locking the fitting projections 43b and the fitting portions 44b together without fail. In this way, the cleaning blade can be easily assembled.

Furthermore, instead of the inclined chamfered portion 43b1 formed on the fitting projection 43b as shown in Fig. 67, the lower portion of the fitting projection may be rounded to have a certain radius of curvature. In this case too, the same technical effect can be achieved.

Further, as shown in Fig. 68, the chamfered portion 43b1 formed on the fitting projection 43b may be rounded to exclude a lower portion of the chamfered portion 43b1. In this case, the fitting projection can be inserted into the fitting portion 44b more smoothly. Furthermore, even if the chamfered portion 43b1 is not formed, if the lower portion of the fitting projection 43b is only rounded as described above, the smoothness of the insertion is improved to some extent.

In addition, Fig. 69 shows an embodiment in which a PTFE tape 13a3 and the like is adhered to the tapered portion 43b1 of the blade support member 13a1, thereby enabling the smooth fitting of the projection into the fitting portion of the system body. Furthermore, Fig. 70 shows another embodiment in which a lubricant 13a4 such as silicon oil, grease or the like is applied to the tapered portion 13b1 to lubricate the tapered portion 13b1, thereby improving the smooth fitting of the fitting projection into the fitting portion of the system body.

In this case, when the tape 13a3 is adhered to the beveled portion, or when the lubricant is adhered to the beveled portion, then, although it it is not necessary to form the chamfered portion 43b1 in the fitting portion 43b, the tape or the lubricant may not be provided at the lower end 43b2 serving as a positioning reference to ensure the accuracy of the attachment.

As described above, the first and second frames can be securely connected to each other, and it is possible to provide a process cartridge and an image forming system that are sufficiently efficient even if the number of reuses (recyclings) is increased.

Furthermore, it is possible to provide a process cartridge, an image forming system and a method of assembling a cleaning device with parts that can be safely installed many times and that are sufficiently efficient even when the number of reuses (recycling) is increased.

Claims (11)

1. A replaceable process cartridge for an image forming apparatus, comprising: a first and a second frame (14, 15); means (14a, 14c, 15a, 15b) for releasably locking the frames together to form a frame assembly; an electrophotographic photosensitive member (9) mounted in the frame assembly; and a processing means (10, 12, 13) mounted in the frame assembly for acting on the photosensitive member; characterized by: a plurality of alignment projections (14e, 14h; 15e) provided on one of the first and second frames, each of the projections being releasably engageable with a respective complementary recess (14d, 15f, 15a) in the other frame by movement along a respective axis, such that the projection, when so engaged, is constrained by the respective recess against movement in a direction transverse to the respective axis, the axes being spaced apart from one another and generally parallel to one another. 2. Cartridge according to claim 1, wherein a plurality of the protrusions (14h) are arranged on the first frame and in a longitudinal direction spaced therefrom, and wherein a corresponding plurality of recesses (15n) are formed by the second frame and in a longitudinal direction spaced therefrom. 3. A cartridge according to claim 2, wherein the locking means comprises a plurality of claws (14a) provided on the first frame alternately with the projections (14h) and engaging with the engaging portions (15b) provided on the second frame. 4. A cartridge according to any preceding claim, wherein the processing means comprises means (12, 12a) for developing a latent image formed on the photosensitive member. 5. A cartridge according to claim 4, wherein the developing means comprises a toner containing portion (12a) formed by the first frame, the locking means comprising a plurality of claws (14a) provided on an outer surface of the toner containing portion and engaging with the engaging portions (15a) formed by the second frame. 6. A cartridge according to any preceding claim, wherein the processing means comprises means (13) for cleaning the photosensitive member. 7. A cartridge according to claim 6, wherein the cleaning means comprises a toner collecting portion (13c) for collecting the toner removed from the photosensitive member, a plurality of the recesses (15n) being formed on the second frames along the toner collecting portion. 8. A cartridge according to any preceding claim, wherein the processing means comprises means (10) for charging the photosensitive member. 9. A cartridge according to claim 8, wherein the loading means comprises a loading roller (10) mounted on the first frame. 10. Cartridge according to one of the preceding claims, wherein the photosensitive member is in the form of a rotatable drum (9). 11. An image forming apparatus comprising a main body, a cartridge as claimed in any preceding claim, and means for removably mounting the cartridge in the main body of the apparatus.