HK1091275B - Developer device and image forming apparatus - Google Patents

Description

Developer device and image forming apparatus

Cross reference to related applications

This application claims priority to japanese patent application No. 2004-.

Technical Field

Aspects of the present application relate to a developer device and an image forming apparatus.

Background

In general, an image forming apparatus such as a laser printer is equipped with a structure for detecting the remaining amount of toner stored in a toner containing section. For example, japanese laid-open patent application No. 2004-118093 discloses a structure for detecting the remaining amount of toner by irradiating light in a toner containing section through a remaining amount detecting window (light transmitting window) 84 provided on a frame of the toner containing section and receiving the light in the light receiving section.

In the above-described image forming apparatus, a structure having a toner inlet provided for toner replenishment (when the amount of remaining toner is small) is widely used. For example, japanese laid-open patent application No. 2004-118093 discloses a structure in which a toner injecting through-hole 82 is formed on the left side wall 55 of the toner containing chamber 76 and a cover member 88 is detachably attached to the toner injecting through-hole 82.

However, a conventional image forming apparatus such as the above-described one is provided with a remaining toner detection window 84 (for detecting the remaining amount of toner) and a toner injection through-hole 82 for toner replenishment independently located in different positions. This results in an increase in the size of the image forming apparatus. In addition, since the window and its corresponding detection system are provided in isolation, the number of parts increases, thereby complicating assembly of the image forming apparatus.

Disclosure of Invention

Aspects of the present invention provide a developing unit having a structure capable of performing both residual toner detection and toner replenishment, thus reducing the size of a system performing these functions and reducing the number of parts required for assembly and/or maintenance, and an image forming apparatus using the same.

The developing unit of the present invention includes: an accommodating frame having a toner storage portion capable of storing toner and a toner inlet communicating with the toner storage portion; and a cover member attached to the housing frame so as to close the toner inlet, the cover member having a light-transmitting portion; wherein the accommodating frame has a first wall portion including the cover member and a second wall portion disposed opposite to the first wall portion, the second wall portion having a window portion disposed facing the cover member, the window portion having light transmissivity; the developing unit further includes: a light projecting section that emits light to detect a toner level surface; and a light receiving portion receiving the light emitted from the light projecting portion via the light transmitting portion and the window portion.

The present invention also provides an image forming apparatus including the developing unit.

Drawings

Exemplary embodiments of the invention will be described in detail with reference to the following drawings, in which:

fig. 1 is a side sectional view of a basic structure of a laser printer as an image forming apparatus according to a first embodiment of the present invention;

FIG. 2 is an enlarged side cross-sectional view of a developer unit according to aspects of the present invention;

FIG. 3 is a cross-sectional view showing the interior of a toner chamber in accordance with aspects of the present invention;

FIG. 4 is a side view of a developer cartridge unit according to aspects of the present invention;

FIG. 5 is a cross-sectional view of a toner inlet taken at line V-V of the unit of FIG. 4, in accordance with aspects of the present invention;

fig. 6 schematically illustrates a drive system for a developer cartridge unit according to various aspects of the present invention; and

fig. 7 shows a toner inlet of an image forming apparatus according to a second embodiment, which is a modification of the cover member shown in the unit of fig. 5 according to aspects of the present invention.

Detailed Description

It is noted that various connections between elements are set forth in the following description. It is noted that, unless specified otherwise, these connections may in general be direct or indirect and that these descriptions are not intended to be limiting in this respect.

< review >

According to aspects of the present invention, a developing unit may include an accommodating frame having a toner storage portion capable of storing toner and a toner inlet communicating with the toner storage portion; and a cover member configured to be removably attached to the receiving frame. The cover member may be attached to the housing frame so as to close the toner inlet and have a light-transmitting portion. The cover member may be at least translucent (including but not limited to being transparent).

The cover member may serve as a window for detecting the toner level surface, and it is not necessary here to separately provide a light-transmitting member for detecting the toner level surface and a movable member for adding toner. In addition, the housing frame does not require the work of mounting such components every time. Therefore, the space of the layout can be saved, and the number of components can be reduced.

According to various aspects of the present invention, the receiving frame may have a first wall portion and a second wall portion disposed opposite to the first wall portion. The first wall portion may include a cover member in a detachable manner, the second wall portion may have a window portion provided facing the cover member, the window portion having light transparency, and a drive gear transmitting a driving force from the driving device to the developing device may be provided on the second wall portion in the accommodating frame.

The driving gear is disposed opposite to the toner inlet, and it can be prevented from being contaminated when the toner is replenished.

According to aspects of the present invention, the toner inlet may be larger in size than the window portion.

The toner inlet port on the side where toner is added has a wide area for toner replenishment, which facilitates the operation. On the other hand, the window portion on the side to which the drive gear is attached has a small area, which effectively increases the flexibility in the arrangement of the drive gear.

According to various aspects of the present invention, the cover member may be made of a light-transmissive material, which may be polycarbonate.

Therefore, the cover member may preferably be configured to transmit light.

According to various aspects of the present invention, the light-transmitting portion of the cover member may be provided inside the inner wall surface of the toner storage portion or the light-transmitting portion and the inner wall surface of the toner storage portion may be flush with each other. A wiper brush that slides on the light-transmitting portion of the cover member may be provided inside the toner storage portion in the housing frame.

Therefore, the wiper can contact the light-transmitting portion, and dust on the light-transmitting portion can be easily removed.

Therefore, the wiper brush is not difficult to move between the light-transmitting portion and the inner wall surface of the toner storage portion, and dust on the light-transmitting portion can be easily removed.

According to aspects of the present invention, the toner inlet may be constituted by a cylindrical portion having a cylindrical inner circumferential surface.

The capping member may be held on the inner surface of the cylindrical portion, and a replenishing tool (e.g., a nozzle) may be appropriately guided during toner replenishment. In addition, the distance between the toner storing portion and the outer surface of the housing frame can be maintained to some extent by the cylindrical portion. Therefore, if the cover member is improperly attached, toner does not leak.

According to aspects of the present invention, the cover member may include an engaging portion inserted into the toner inlet, and a positioning portion controlling the cover member to move to the inside of the accommodating frame.

Therefore, the cover member can be stably positioned.

According to aspects of the present invention, a sheet-shaped adhesive medium may be disposed between the positioning portion and the end of the cylindrical portion.

Therefore, the cover member can be effectively prevented from falling off. The gap between the capping member and the toner inlet is filled with the adhesive medium, so that leakage of toner is prevented. Because the bonding medium is disposed to the end, it can be easily removed for recycling.

According to aspects of the present invention, the toner inlet may be constituted by a cylindrical portion protruding outward from an outer wall surface of the toner storage portion.

Therefore, the cover member can be firmly attached and the cylindrical portion does not interfere with any component in the toner storage portion.

According to various aspects of the present invention, an image forming apparatus may include a developing unit. The developing unit may include a housing frame having a toner storage portion capable of storing toner and a toner inlet communicating with the toner storage portion; the cover member is configured to be removably attached to the receiving frame. The cover member may be attached to the housing frame so as to close the toner inlet and have a light-transmitting portion. The receiving frame may have a first wall portion and a second wall portion disposed opposite to the first wall portion. The first wall portion may include a cover member in a detachable manner, the second wall portion may have a window portion provided facing the cover member, the window portion having light transparency, and a drive gear transmitting a driving force from the driving device to the developing device may be provided on the second wall portion in the accommodating frame. The image forming apparatus may further include a light projecting section that emits light to detect the toner level surface; and a light receiving portion receiving the light emitted from the light projecting portion via the light transmitting portion or the window portion.

Therefore, the toner level surface can be stably detected with a simple structure.

In further aspects of the invention, the invention may include a method of determining a toner level in a toner cartridge having a toner inlet covered by a cover member, where the method includes emitting light from one side of the toner cartridge and receiving light at a second side of the toner cartridge, the light passing through the cover member.

In some aspects of the invention, the cover member is detachable from the toner cartridge. In other aspects, the cap member is not separable from the toner cartridge. When detachable, the toner cartridge may be easily broken if it is to be refilled with a cover member to replace the single use component. In other aspects of the invention, the cap member may be reusable after the toner cartridge is refilled for reuse. In both of the above aspects, the cover member is detachable from the toner cartridge.

< first embodiment >

A first embodiment of the present invention will be described in detail with reference to fig. 1 to 6.

(1, integral Structure)

In fig. 1, a laser printer 1 includes, in a main body casing 2, a feeding unit 4 for supplying a sheet 3 and an image forming unit 5 for forming a prescribed image on the supplied sheet 3.

The feeding unit 4 includes a sheet feeding tray 41, a pressing plate 6, a sheet feeding roller 7, a sheet feeding pad 8, and a registration roller 9. The sheet feed tray 41 is detachably attached to the bottom of the main body casing 2. The platen 6 is provided in the sheet feed tray 41. The sheet feeding roller 7 and the sheet feeding pad 8 are disposed above one end of the sheet feeding tray 41. The registration roller 9 is disposed downstream of the sheet feed roller 7 with respect to the sheet conveying direction.

The platen 6 has sheets stacked thereon. The platen 6 is pivotally supported at its end remote from the paper feed roller 7 such that the platen 6 is vertically movable at its end closest to the paper feed roller 7. The pressing plate 6 is urged upward from its back or bottom side by a spring (not shown). When the number of stacked sheets 3 increases, the pressing plate 6 swings downward around the end away from the sheet feeding roller 7 against the urging force of the spring.

The paper feed roller 7 and the paper feed pad 8 are disposed opposite to each other. The sheet feeding pad 8 is urged toward the sheet feeding roller 7 by a spring 10 provided on the back of the sheet feeding pad 8. The uppermost sheet 3 in the stack on the pressing plate 6 is pressed against the sheet feeding roller 7 by a spring 8 (not shown) provided on the back of the pressing plate 6, and when the sheet feeding roller 7 rotates, the uppermost sheet 3 is sandwiched between the sheet feeding roller 7 and the sheet feeding pad 8. Thus, the sheets 3 are fed one by one from the top of the stack.

The registration roller 9 is composed of two rollers located on the driving side and the driven side, respectively, and is used to convey the sheet 3, and the sheet 3 is conveyed from the sheet feed roller 7 to the image forming unit 5 after being registered or the skew of the sheet is corrected.

The image forming unit 5 includes a scanner unit 11, a process unit 12, and a fixing unit 13.

The scanning unit 11 is provided at an upper portion of the main body casing 2 and has a laser emitting portion (not shown), a rotatable polygon mirror 14, lenses 15, 16, and reflecting mirrors 17, 18, 19. The laser beam emitted from the laser emission position based on predetermined image data passes through or is reflected from the optical element in the order of the polygon mirror 14, the lens 15, the mirrors 17, 18, the lens 16, and the mirror 19, as shown by the broken line in fig. 1. Thus, the laser beam is guided to and scanned at high speed over the surface of the photosensitive drum 21 of the process unit 12, which will be described later.

The processing unit 12 is provided below the scanner unit 11 so as to be detachably attached with respect to the apparatus main body 1 a. In the present embodiment, the apparatus main body 1a refers to the entirety of the laser printer 1 except for the process cartridge 20. The process unit 12 includes a drum cartridge 20 detachably attached to the main body casing 2, and a developing cartridge 36 detachably attached to the drum cartridge 20. The developing cartridge 36 functions as a developing unit. The drum cartridge 20 includes a photosensitive drum 21, a transfer roller 26, and a scorotron charger 25. Therefore, the developing cartridge 36 is configured to be separated from the photosensitive drum 21 and the scorotron charger 25.

The developing cartridge 36 is partitioned into a developing chamber 51 for toner development and a toner chamber 27 (as a toner storing portion) for storing toner therein. The developing roller 22, the layer thickness regulating blade 23 as a layer thickness regulating member, and the supply roller 24 are accommodated in the developing chamber 51.

The developing chamber 51 and the toner chamber 27 are partitioned by an upper partition wall 53 and a lower partition wall 54. A substantially rectangular opening 52 extending in the width direction is formed between the upper partition wall 53 and the lower partition wall 54. The opening 52 is opened so that the toner circulates in the toner chamber 27 and the developing chamber 51.

The toner chamber 27 contains positively charged non-magnetic mono-component toner as a developer. When the positively charged non-magnetic mono-component toner is used, it can be developed on the positively charged photosensitive drum 21. That is, when negatively charged toner is used, the photosensitive drum 21 must be negatively charged. However, if the photosensitive drum 21 is negatively charged using the scorotron charger 25 in a non-contact state, a large amount of ozone will be generated. In addition, in order to prevent the generation of ozone, if the photosensitive drum 21 is charged in a contact state using a member such as a transfer roller or a brush, it will not be uniformly charged. On the other hand, in order to positively charge the photosensitive drum 21, even if the scorotron charger 25 is used for non-contact charging, the generation of ozone will be extremely low, and the photosensitive drum 21 can be uniformly charged. The toner used in the present embodiment is a polymerized toner obtained by copolymerizing a styrene-based monomer such as styrene and an acrylic-based monomer such as acrylic acid, alkyl (C1-4C) acrylate, and alkyl (C1-4C) methacrylate by a known polymerization method such as suspension polymerization. The polymerized toner has a styrene-acrylic-based resin as a main component. A coloring agent such as carbon black, a charge control agent such as nigrosine, and paraffin are added to the polymerized toner. An external additive such as silica is also added to the polymerized toner. This polymerized toner in the form of particles is substantially spherical and the average particle size of the toner is about 6 to 10 μm. Since such a polymerized toner has particles of a uniform diameter, the particles are formed to be approximately spherical, and thus the polymerized toner has excellent fluidity. In this way, the toner in the developing cartridge 36 is efficiently circulated by agitation by the agitator 29, which will be described later, facilitating charging efficiency and formation of a high-quality image. The agitator 29 may include, but is not limited to, the agitator 29 and associated components of U.S. patent No. 6,337,956, the contents of which are expressly incorporated herein by reference.

The photosensitive drum 21 is provided on the side of the developing roller 22 so as to be in contact with the developing roller 22 and to rotate in the direction of the arrow (clockwise direction). The photosensitive drum 21 is constituted such that a drum main body is grounded and its surface is formed of a positively chargeable material such as an organic photoconductor of which polycarbonate is a main component.

The scorotron charger 25 is disposed above the photosensitive drum 21 at a predetermined distance therefrom. The scorotron charger 25 is a positively charged scorotron charger that generates corona discharge from a charging wire such as a tungsten wire and is designed to positively charge the surface of the photosensitive drum 21 uniformly.

The surface of the photosensitive drum 21 is positively and uniformly charged by a scorotron charger 25, and then exposed by high-speed scanning of a laser beam from the scanner unit 11. An electrostatic latent image based on the designated image data is formed on the surface of the photosensitive drum 21. With the rotation of the developing roller 22, the toner carried by the developing roller 22 and positively charged is selectively transferred to the electrostatic latent image formed on the surface of the photosensitive drum 21, where it is a low potential region of the photosensitive drum 21, which is photosensitive by the laser beam. Therefore, the electrostatic latent image becomes visible, and development (reversal development) is completed.

The transfer roller 26 is disposed below the photosensitive drum 21, faces the photosensitive drum 21, and rotates in the arrow (counterclockwise) direction. The transfer roller 26 is formed by covering a roller body made of a conductive rubber material on a metal roller, and a specified transfer bias is applied to the transfer roller 26. Therefore, the toner developed on the photosensitive drum 21 is transferred onto the paper 3 when the paper 3 passes between the photosensitive drum 21 and the transfer roller 26.

As shown in fig. 1, the fixing unit 13 is disposed on the downstream side of the process unit 12. The fixing unit 13 includes a heating roller 32, a pressing roller 31 pressed by the heating roller 32, and a pair of conveying rollers 33 disposed downstream of the heating roller 32 and the pressing roller 31. The heating roller 32 is equipped with a halogen lamp made of metal for heating. In the process unit 12, the toner transferred onto the sheet 3 is fixed by heating while the sheet 3 passes between the heating roller 32 and the pressing roller 31, and the sheet 3 is conveyed to a pair of paper discharge rollers 34 by a conveying roller 33. The sheet 3 conveyed to the sheet discharge roller 34 is discharged onto the output tray 35 by the sheet discharge roller 34.

The laser printer 1 is designed to use a cleaner-less method to collect toner remaining on the photosensitive drum 21 after a visible image is transferred. In the cleanerless method, the toner remaining on the photosensitive drum 21 after the visible image is transferred is made to face the scorotron charger 25 with the rotation of the photosensitive drum 21, and is uniformly positively charged by the scorotron charger 25. Then, as the photosensitive drum 21 rotates, the toner remaining on the photosensitive drum 21 is caused to face the developing roller 22 and is collected by the developing roller 22 to which the developing bias is applied.

(2, inner structure of developing cartridge)

The internal structure of the developing cartridge will be described with reference to fig. 2 and 3. Fig. 2 shows an enlarged view of the processing unit 12. Fig. 3 shows a sectional view of the inside of the toner chamber 27. In fig. 3, the agitator 29 and the wiper brush 39 are shown to extend in a vertical direction (a direction parallel to the upper partition wall 53) and are not shown in the positions shown in fig. 2 for the sake of simplicity of description.

As shown in fig. 2 and 3, the toner chamber 27 is provided with an agitator 29 for agitating the toner to supply it from the opening 52 to the developing chamber 51, a wiper 39 for cleaning the window portion 58 and the capping member 100, and a rotary shaft 28 supporting the agitator 29 and the wiper 39.

The rotary shaft 28 extends to opposite side walls (a first side wall 57 and a second side wall 56) of the toner chamber 27 at a substantially central portion of the toner chamber 27, and protrudes from the second side wall 56 of the toner chamber 27 at one end thereof. A rotation shaft gear 44 is provided at one end of the shaft protrusion to drive and rotate the rotation shaft 28. The first side wall 57 serves as a first wall portion and the second side wall 56 serves as a second wall portion.

As shown in fig. 3, the cover member 100 is shown relative to the first sidewall 57, while the spindle gear 44 is shown relative to the second sidewall 56. In alternative aspects, the cover member 100 and the spindle gear 44 may be located on the same side wall. Having the capping member 100 (and toner inlet 110) on the side away from the shaft gear 44 may help prevent toner from accumulating, tangling, and/or interfering with the shaft gear 44. On the other hand, having the cover member 100 (and the toner inlet 110) on the same side of the shaft gear 44 may facilitate manufacturing and/or provide a larger space for the toner chamber 27.

An agitator 29 is provided to the shaft 28 along the length of the shaft as shown in figures 2 and 3. The agitator 29 includes a support member 42 and a sliding contact member 43. The support member 42 is made of resin and extends radially outward from the rotating shaft 28. The sliding contact member 43 is attached to the end of the support member 42 and formed of a thin film made of, for example, polyethylene terephthalate.

The agitator 29 rotates in the toner chamber 27 with the rotation of the rotary shaft 28, and the sliding contact member 43 slides in a curved state on the bottom surface of the toner chamber 27 formed substantially in a cylindrical shape, pushing up the toner and discharging it from the opening 52 to the developing chamber 51.

During the rotation of the agitator 29, a large resistance is received when the supporting member 42 pushes up the toner and the sliding contact member 43. However, in order to reduce the resistance caused by the toner, the openings 45 are formed in the supporting member 42 at regular intervals in the longitudinal direction thereof.

The wiper brushes 39 are disposed on both sides of the rotary shaft 28 with respect to the longitudinal direction of the rotary shaft, on opposite sides of 180 degrees with respect to the agitator 29. The wiper 39 includes a support member 46 and a cleaning member 47. The support member 46 is made of resin and extends radially outward from the rotary shaft 28, and the cleaning member 47 is made of urethane rubber and is provided at an outer end of the support member 46.

The wiper 39 rotates in the toner chamber 27 with the rotation of the rotary shaft 28. Due to the rotation of the wiper brush 39, each cleaning member 47 contacts the window portion 58 and the cover member 100, thereby wiping the toner adhering to the inner surfaces of the window portion 58 and the cover member 100 in the chamber. Since the agitator 29 and the wiper brush 39 are supported by the rotary shaft 28, the window portion 58 and the lid member 100 are cleaned by the wiper brush 39 in the cycle in which the agitator 29 rotates, regardless of the rotational speed of the agitator 29. Therefore, the toner level surface can be accurately and reliably detected by the toner detection optical sensor 62.

As shown in fig. 2, the agitator 29 includes a substantially fan-shaped light shielding plate 85. With the light shielding plate 85, the time for shielding the light of the optical sensor 62 for toner detection in one rotation of the agitator 29 can be defined longer, thereby reducing improper detection, so that more accurate detection can be achieved.

On the other hand, the supply roller 24 is disposed close to the opening 52 in the developing chamber 51 so as to rotate in the arrow direction (counterclockwise direction) in fig. 2. The developing roller 22 is disposed to face the supply roller 24 so as to rotate in the arrow direction (clockwise direction). The supply roller 24 and the developing roller 22 are compressed to some extent in contact with each other.

The supply roller 24 is formed by covering a metal roller shaft with a roller body made of a conductive foam material. The developing roller 22 is formed by covering a metal roller shaft with a roller body made of a conductive rubber material. More specifically, the roller body of the developing roller 22 is made of polyurethane or silicone rubber containing carbon particles, and is covered with a coating of polyurethane or silicone rubber containing fluorine. Thus, since the surface of the developing roller 22 is covered with the coating layer of polyurethane or silicone rubber containing fluorine having a negative charge polarity, the positive charge polarity of the toner held on the surface can be improved. A prescribed developing bias causing a potential difference with the photosensitive drum 21 is applied to the developing roller 22.

The layer thickness regulating blade 23 is provided in the vicinity of the developing roller 22. The layer thickness regulating blade 23 includes a blade body 37 and a pressing member 38. The blade body 37 is made of a metal leaf spring member. A pressing member 38 formed in a semicircular shape is provided at an end portion of the blade body 37 and made of silicone rubber having insulation properties. The layer thickness regulating blade 23 is constituted such that one end of the blade body 37 opposed to the pressing member 38 is supported by a frame 36a (as an accommodating frame) of the developing cartridge 36 in the vicinity of the developing roller 22, and the pressing member 38 is pressed into contact with the developing roller 22 by the elastic force of the blade body 37.

The toner discharged from the opening 52 to the developing chamber 51 is supplied to the developing roller 22 with the rotation of the supply roller 24, and at the same time, is positively charged by the friction between the supply roller 24 and the developing roller 22. The toner supplied onto the developing roller 22 enters between the pressing portion 38 of the layer thickness regulating blade 23 and the developing roller 22 with the rotation of the developing roller 22. The toner is sufficiently charged by friction and by friction between the pressing portion 38 and the developing roller 22, and is held on the developing roller 22 as a thin layer having a substantially uniform thickness.

(3, Structure for detecting toner level surface)

The structure for detecting the toner level in the developing cartridge 36 will be described below. Fig. 4 is a side view of the developing cartridge 36 viewed from the inlet side of the toner. Fig. 5 is a sectional view of the vicinity of the toner inlet taken along the line V-V of fig. 4. As shown in fig. 3, the frame 36a of the developing cartridge 36 forms a toner chamber 27 for storing toner, and a toner inlet 110 communicating with the toner chamber 27 for introducing toner.

As shown in fig. 3 and 4, the frame 36a of the developing cartridge 36 has formed thereon a first side wall 57 and a second side wall 56 disposed to face each other. The toner inlet 110 is formed in the first side wall 57 so as to include a cylindrical inner circumferential surface 110a, and is constituted as a protruding cylindrical portion that protrudes further outward than the outer wall surface 57a of the first side wall 57 (i.e., the outer wall surface of the toner chamber 27).

As shown in fig. 5, the cover member 100 is detachably attached with respect to the toner chamber 27. Specifically, the cover member 100 is detachably provided on the first side wall 57 where the toner inlet 110 is provided, thereby sealing the toner inlet 110.

The cover member 100 is provided with a light-transmitting portion 106 through which light is transmitted to detect the toner level surface. The light-transmitting portion 106 is designed to allow transmission of light from the toner detection optical sensor 62 (fig. 3). In the present embodiment, the entire cover member 100 has optical transparency. When the cover member 100 is attached, the wall portion 104 facing the inside of the toner chamber 27 serves as a light-transmitting portion 106, and allows light to be transmitted in the thickness direction thereof. With this structure, the cover member 100 functions not only as a member for sealing the toner inlet 110 but also as a window for detecting the toner level surface. This structure enables the light-transmitting portion for detecting the toner level surface and the movable portion to which the toner is added to be shared in a single component. In addition, the frame 36a does not need to perform the work of a plurality of functions (such as a function of toner replenishment and a function of detecting a toner level) each time. Therefore, the space of the layout can be saved, the number of parts can be reduced, and the improvement of the manufacturing can be effectively achieved. In addition, the cover member 100 is made of polycarbonate. It may also be made of other resin materials or glass materials that can allow light transmission.

Further, in the present embodiment, the cover member 100 can be stably held by providing the cylindrical inner circumferential surface 110a, while it can accurately guide a tool (e.g., a nozzle) for replenishment in the case of toner replenishment. Since the toner inlet 110 is formed in a cylindrical shape, the distance from the toner chamber 27 to the outside can be maintained to some extent. Therefore, if the cover member 100 is improperly attached, toner is less likely to leak.

As shown in fig. 5, the cover member 100 has an engaging portion 102 and a positioning portion 103 which are inserted into the toner inlet 110, so as to be supported by an end portion 110b of the toner inlet 110 provided on the side where the cover member 100 is inserted. The positioning portion 103 is supported by the end portion 110b so as to control the movement of the cover member 100 to the inside of the frame 36 a.

The sheet-like adhesive medium 105 is disposed between the positioning portion 103 and the end 110b of the toner inlet 110. The adhesive medium 105 is composed of a double-sided tape in which a face 105a facing the end portion 110b and a face 105b facing the positioning portion 103 are uncovered as an adhesive portion. An adhesive medium 105 is annularly provided around the cover member 100, thereby adhering the positioning portion 103 and the end portion 110 b. The cover member 100 can be prevented from falling off. The gap between the cover member 100 and the toner inlet 110 is filled with the adhesive medium 105, and therefore toner leakage can be avoided. Because the bonding medium 105 is disposed to the end 110b, it can be easily removed for recycling.

As shown in fig. 3, the window portion 58 having light transparency is provided on the side wall opposite to the cover member 100 (i.e., on the second side wall 56) so as to face the cover member 100. The window portion 58 includes an opening portion formed in the second side wall 56 and a resin member having light transparency to block the opening portion (in other words, the opening portion formed in the second side wall 56 is closed by the resin member). The configuration of the resin member makes it difficult to be detachably attached to the second side wall 56.

In the present embodiment, the toner inlet 110 is configured to be larger in size than the window portion 58 and to have a wide area for toner replenishment, thereby facilitating the operation. On the other hand, the window portion 58 on the side to which the drive gear is attached has a small area, thereby effectively increasing the flexibility of the drive gear arrangement.

As shown in fig. 5, the light-transmitting portion 106 and the inner wall surface 57b of the first side wall 57 (or the inner wall surface of the toner chamber 27) are configured such that they are flush with each other. Specifically, the inner side surface 104 of the light-transmitting portion 106 and the inner wall surface 57b of the first sidewall 57 are disposed on the same imaginary plane F.

In other words, as described above, the cleaning member 47 is disposed inside the toner chamber 27 in the frame 36a so as to slide in contact with the light-transmitting portion 106 of the cover member 100. However, in the present embodiment, cleaning member 47 is not difficult to move between light-transmitting portion 106 and inner wall surface 57b of first side wall 57, and dirt on light-transmitting portion 106 can be easily removed.

As shown in fig. 3, the apparatus body 1a of the laser printer 1 is provided with a toner detection optical sensor 62 for detecting the toner level remaining in the toner chamber 27. The toner detection optical sensor 62 includes a light projecting portion 60 having light emitting means and projecting light for detecting a toner level surface, and a light receiving portion 61 having light receiving means and receiving light from the light projecting portion 60. The light from the light projecting portion 60 to the light receiving portion 61 is conceptually represented by a double dotted line L.

In other words, in fig. 3, the window portion 58 and the cover member 100 are provided on the two side walls 56, 57 of the toner chamber 27, respectively, so that they can face each other at a position closer to the opening 52 than the center of the toner chamber 27. The light projecting portion 60 and the light receiving portion 61 are attached to frames 63, 64 of the main body casing 2, which face the window portion 58 and the cover member 100, respectively.

Specifically, the lens 65 is embedded in the frame 63 facing the window portion 58, the support base 69 is supported via the holding member 67 at a position facing the lens 65 outward, and the light projecting portion 60 is provided on the support base 69 such that the light emitting device faces the lens 65. The lens 66 is embedded in the frame 64 facing the cover member 100. The support base 70 is supported via the holding member 68 at a position facing the lens 66 outward. The light receiving portion 61 is disposed on the support substrate 70 such that the light receiving device faces the lens 66.

In fig. 3, the casing portion 40 of the drum cartridge 20 is shown in a substantially recessed state so as to enclose the lower side of the developing cartridge 36. Opening portions 71, 72 are formed on both side walls of the case portion 40 facing the window portion 58 and the lid member 100.

Thus, the light projecting portion 60, the lens 65, the opening 71, the window portion 58, the light receiving portion 61, the lens 66, the opening portion 72, and the cover member 100 are arranged on a straight line crossing the toner cavity 27. With this arrangement, light having strong directivity (such as a laser beam) emitted from the light projecting portion 60 passes through the toner chamber 27 via the lens 65, the opening 71, and the window portion 58, and is received by the light receiving portion 61 via the cover member 100, the opening 72, and the lens 66.

In the light receiving portion 61, the voltage output from the light receiving device varies according to the amount of received light. If the amount of received light is small, the output voltage is high (e.g. 5V), and if the amount is large, the output voltage is low (e.g. 0V). Thus, a change in the output voltage is detected, and it can therefore be detected whether or not the light that has passed through the toner chamber 27 is blocked by the remaining toner.

According to the optical sensor 62 for toner detection, when the toner remaining in the toner chamber 27 is sufficiently large, the light connecting the light projecting portion 60 and the light receiving portion 61 is blocked by the toner, and thus it can be detected correctly and reliably that the toner is not yet required to be supplied. When the toner in the toner chamber 27 becomes less or no toner, the light connecting the light projecting section 60 and the light receiving section 61 is not blocked by the toner, and therefore the need for replenishment of the toner can be detected correctly and reliably.

(4, drive System)

Fig. 6 schematically shows a driving system of the developing cartridge 36. In fig. 6, the developing cartridge 36 includes an agitator-side input gear 73 and a developing roller-side input gear 74, both serving as input gears to which drive from the main body casing 2 is transmitted. The agitator-side input gear 73 is provided on the side of the toner chamber 27 with respect to its width. The developing roller side input gear 74 is provided on the side of the developing chamber 51 with respect to the width thereof. The drive system of the agitator and the drive system of the developing roller 22 are not connected in the developing cartridge 36. They are independently constructed. The developing roller side input gear 74 serves as a driving gear.

The agitator-side input gear 73 is configured to mesh with the rotation shaft gear 44 provided around the rotation shaft 28, and to receive transmission of drive from a sub motor (not shown) provided in the main body casing 2 when the developing cartridge 36 is attached to the main body casing 2. Therefore, the drive from the sub motor is transmitted to the shaft gear 44 via the agitator-side input gear 73, the shaft gear 44 is driven, the shaft 28 rotates, and then the agitator 29 and the wiper 39 rotate in the toner chamber 27.

The developing roller side input gear 74 is configured to mesh with a developing roller gear 76 and a supply roller gear 77, wherein the developing roller gear 76 is disposed around the roller shaft of the developing roller 22 on the side of the developing chamber 51 with respect to its width, and the supply roller gear 77 is disposed around the roller shaft of the supply roller 24 on the developing chamber 51 side. When the developing roller 22 is attached to the main body casing 2, the developing roller side input gear 74 is also configured to mesh with a transmission gear 78 (shown by a double dotted line), thereby receiving transmission from the drive of a main motor M (shown by a double dotted line) provided in the main body casing 2. Specifically, the drive from the main motor M is transmitted to the developing roller side input gear 74 via the transmission gear 78 interlocked with the main motor M, and further transmitted to the developing roller gear 76 and the supply roller gear 77, respectively. When the developing roller gear 76 and the supply roller gear 77 are driven, the developing roller 22 and the supply roller 24 rotate independently.

The drive from the main motor M is used to drive the respective rollers such as the photosensitive drum 21, the transfer roller 26, and the heating roller 32, and the developing roller side input gear 74. The drive from the sub motor is used only to drive the agitator-side input gear 73.

In the present embodiment, a developing roller side input gear 74 designed to transmit a driving force from a driving device (main motor M) to the developing roller 22 is provided on the second side wall 56 of the frame 36 a. In other words, since the gears are located on the side opposite to the toner inlet 100, they will not be dirtied by toner during toner replenishment. In addition, the window portion 58 smaller than the toner inlet 110 is located on the second side wall 56 opposite to the toner inlet 110, thereby effectively increasing the flexibility of the gear arrangement such as the developing roller side input gear 74.

< second embodiment >

A second embodiment of the present invention will be described with reference to fig. 7. Fig. 7 shows a toner inlet of an image forming apparatus according to a second embodiment, which is a modification of the cover member shown in fig. 5. In the present embodiment, unlike the first embodiment, the light-transmitting portion 106 of the cover member 100 is disposed further inside than the inner wall surface of the toner chamber 27 (the inner wall surface of the first side wall 57). Note that elements similar or identical to those of the first embodiment are denoted by similar numerals, and thus the description thereof is omitted for the sake of brevity. Also in this embodiment, a wiper similar to the first embodiment and sliding on the light-transmitting portion 106 of the cover member 100 is provided inside the toner chamber 27 in the frame 36 a. Such a cleaning member is more likely to contact the light-transmitting portion 106, so that dirt on the light-transmitting portion 106 can be easily removed.

< other examples >

In the above embodiment, the developing unit is constituted by the developing cartridge 36. However, the process unit including the image holding member may be configured as a developing unit. For example, in the case where the frame does not include a toner chamber detachably attached to the drum cartridge, the frame including the toner chamber and the drum cartridge may be formed in one unit as a developing unit.

In the above-described embodiment, the developing unit is configured to be detachably attached to the apparatus main body 1a, but it is not limited thereto. The developing unit may be configured such that a toner chamber for storing toner may be fixed to the main body casing.

In the above-described embodiment, the driving system of the agitator 29 and the driving system of the developing roller 22 are not connected in the developing cartridge 36, and are constituted independently of each other. However, they may be combined into one drive system. For example, the developing roller 22 and the agitator 29 may be configured to be driven together by a driving force from a single driving unit (e.g., a main motor). In this case, a single driving unit may serve as the driving unit.

While various aspects of the invention have been described in conjunction with the exemplary teachings above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having ordinary skill in the art. Accordingly, the exemplary aspects of the invention described above are to be considered for purposes of illustration, and not limitation. Various changes may be made without departing from the spirit and scope of the invention. Accordingly, the invention is intended to embrace all known or later-developed alternatives, modifications, variations, improvements and/or substantial equivalents.

Claims (9)

1. An imaging apparatus (1), characterized by comprising:

a developing unit (36), the developing unit (36) comprising:

a housing frame (36a), the housing frame (36a) having a first wall portion (57) and a second wall portion (56) disposed opposite the first wall portion (57), the first wall portion (57) and the second wall portion (56) defining a toner storage portion (27) configured to store toner therein, a toner inlet (110) being formed with the first wall portion (57) and communicating with the toner storage portion (27); and

a cover member (100) attached to the first wall portion (57) and configured to detachably close the toner inlet (110), the cover member (100) having a light-transmitting portion (106), wherein the second wall portion (56) has a window portion (58) provided facing the cover member (100), the window portion having light-transmitting properties, and a drive gear (74) that transmits a driving force to the developing device (22) is provided on the second wall portion (56); and

a light projecting portion (60) that emits light; and

a light receiving portion (61) that receives light emitted from the light projecting portion (60) and passing through the light transmitting portion (106) and the window portion (58) of the cover member (100), wherein the toner level is detected based on the light received by the light receiving portion (61),

wherein the light-transmitting portion (106) of the cover member (100) and the inner wall surface of the toner storage portion (27) are flush with each other.

2. An imaging apparatus (1) as claimed in claim 1, wherein the first wall portion (57) further comprises:

a cylindrical portion having a cylindrical inner circumferential surface (110a) surrounding the toner inlet (110), the cylindrical portion having an end portion (110b) protruding outward from an outer surface of the first wall portion (57),

the cover member (100) further comprises:

an engagement portion (102) configured to be inserted into the cylindrical portion, an

A positioning portion (103) extending from the engaging portion (102) and facing an end portion (110b) of the cylindrical portion when the engaging portion (102) is inserted into the cylindrical portion,

the developing unit further includes:

and a sheet-like adhesive medium (105) disposed between the positioning portion (103) and the end portion (110b) of the cylindrical portion.

3. An imaging apparatus (1) according to claim 1, wherein said cover member (100) is reusable.

4. An imaging apparatus (1) according to claim 1, wherein said cover member (100) is non-reusable.

5. The image forming apparatus (1) as claimed in claim 1, wherein the toner inlet (110) is larger in size than the window portion (58).

6. An imaging apparatus (1) according to claim 1, wherein the cover member (100) is made of a light-transmissive material.

7. An imaging device (1) as claimed in claim 6, characterized in that the light-transmitting material is polycarbonate.

8. The image forming apparatus (1) according to claim 1, wherein the developing unit (36) further comprises: and a wiper brush (39) disposed inside the toner storage portion (27), wherein the wiper brush (39) slides on the light-transmitting portion (106) of the cover member (100).

9. The image forming apparatus (1) according to claim 8, wherein the developing unit (36) further comprises: an agitator (29) provided inside the toner storage portion (27), the agitator (29) being configured to rotate integrally with the wiper brush (39).