JP2003208024A - Driving device and color image forming apparatus - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] In an in-line color image forming apparatus, a drive device employing a small, low-cost mechanical clutch that reliably intermittently outputs a relatively large torque even when the drive side is rotating. I will provide a. SOLUTION: A plurality of process cartridges 7 are provided in parallel,
In a driving device used for a color image shaping device having a separation plate 80 for separating the photosensitive drum 1 from the developing roller 40, a clutch CL for controlling rotation and stop of the developing roller 40 is provided.
The gear 111, which is rotatably restricted in the axial direction and transmits the drive from the motor 100 side, the drive-side engagement part 113, the driven-side engagement part 114, the coil spring 112, and the drive-side engagement part 113
Axial member 115 for axially moving and engaging and releasing
A lever member 116, and the drive-side engagement component 113 and the driven-side engagement component 114 have a plurality of drive transmission surfaces inclined in a direction of biting each other when engaged, and the drive transmission surface Are arranged symmetrically with respect to.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device used in a copying machine, a printer or the like and a color image forming apparatus equipped with the driving device.

[0002]

2. Description of the Related Art In an in-line type color image forming apparatus, in order to solve the problem of wasting developer, there is a method of controlling the rotation of the electrophotographic photosensitive member and the developing device separately to minimize the rotation of the developing device. It is considered. Further, as a measure against the color shift of a plurality of colors peculiar to in-line, a method of controlling the rotation of the photoconductor by a motor independent for each color has been adopted. In order to realize a combination of the both at low cost, the photosensitive member and the developing device are driven by one motor for each color, and rotation is performed for developing drive.
A possible method is to put in a clutch that controls stopping.

In the development drive of the conventional image forming apparatus, an electromagnetic clutch or a spring clutch is often used, but there are problems such as high cost, limited shape, and malfunction due to slip.

As a mechanical clutch for avoiding this, there is a planetary clutch that engages with and separates from a mating gear when the gear revolves.

[0005]

However, in the planetary clutch described above, tooth surface wear caused by the impact of meshing causes image defects such as pitch unevenness. Further, there is a problem such as deterioration of efficiency due to idling torque for ensuring the operation of the planetary gears. Further, since the motor is rotated forward and backward when connecting and disconnecting the drive, it is not suitable for a configuration in which the photosensitive member and the developing device are simultaneously driven by one motor.

For this reason, in the development drive of the conventional in-line color image forming apparatus, a mechanical clutch having excellent cost and reliability, which enables intermittent driving even while the photosensitive member is rotating, is not used. It was

Therefore, the present invention employs a small-sized and low-cost mechanical clutch that is particularly effective in an in-line color image forming apparatus and is capable of reliably interrupting a relatively large torque even when the drive side is rotating. It is an object of the present invention to provide such a driving device.

[0008]

In order to solve the above-mentioned problems, a typical structure of a driving device and a color image forming apparatus according to the present invention is to install a plurality of process cartridges each having an electrophotographic photosensitive member and developing means. In a driving device used in a color image forming apparatus having a separating means for separating an electrophotographic photosensitive member and a developing roller, a clutch for controlling rotation and stop of the developing roller is provided, and the clutch is a driven-side rotating shaft. In contrast, a drive component that is rotatably regulated in the axial direction and that transmits drive from the motor side, a drive-side engagement component that rotates in the same direction as the drive component and is movable in the axial direction, and a driven-side component. A driven side engaging part that is fixed to the rotating shaft and that engages with the driving side engaging part, an elastic member that urges the driving side engaging part in a direction to engage the driven side engaging part, and a driving side engaging part. Axially Dynamic is allowed to engage, and a control means for releasing the drive-side engaging parts and the driven-side engaging part,
It is characterized in that it has a plurality of drive transmission surfaces that are inclined in a direction in which they engage each other when engaged, and the drive transmission surfaces are arranged symmetrically with respect to the center of rotation.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a driving device and a color image forming apparatus according to the present invention will be described with reference to the drawings. 1 is a sectional view of a color image forming apparatus according to the present embodiment, FIG. 2 is a sectional view of a process cartridge, FIG. 3 is a perspective view of a process cartridge, and FIG. 4 is a method of mounting the process cartridge in the color image forming apparatus. Perspective view,
5 is a partial cross-sectional view showing the positioning portion of the process cartridge with respect to the color image forming apparatus, FIG. 6 is a partial cross-sectional view showing the positioning portion of the process cartridge with respect to the color image forming apparatus, and FIG. FIG. 8 is a sectional view showing the process cartridge in a black separation release state and another color separation state, FIG. 9 is a perspective view showing an operation switching mechanism, FIG. 10 is a perspective view of a drive unit for driving the cartridge, and FIG. Is a perspective view showing a mechanical clutch,
FIG. 12 is a schematic diagram showing the state of the clutch during full-color recording, and FIG. 13 is a schematic diagram showing the state of the clutch during mono-color recording.

[Overall Configuration] First, the overall configuration of the color image forming apparatus will be outlined with reference to FIG. In addition,
FIG. 1 is a vertical cross-sectional view showing the overall configuration of a full-color laser beam printer A which is one mode of a color image forming apparatus.

As shown in FIG. 1, a color image forming apparatus A
Are four photosensitive drums 1a, 1a arranged in parallel in the vertical direction.
b, 1c, 1d. The photosensitive drum 1 is shown in FIG.
It is driven to rotate counterclockwise in FIG.

A charging device 2 (2a, 2b, 2c, 2d) for uniformly charging the surface of the photoconductor drum 1 is sequentially irradiated around the photoconductor drum 1 in accordance with the rotation direction thereof, and a laser beam is irradiated based on image information. The scanner unit 3 (3a, 3b, 3c, which forms an electrostatic latent image on the photosensitive drum 1)
3d), a developing device 4 (4a, 4b, 4c, 4d) (developing unit) that attaches toner to the electrostatic latent image and develops it as a toner image, and transfers the toner image on the photosensitive drum 1 to the transfer material S. Electrostatic transfer device 5 and cleaning device 6 for removing transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer
(6a, 6b, 6c, 6d) and the like are provided.

Here, the photosensitive drum 1, the charging device 2, the developing unit 4, and the cleaning device 6 are integrally formed into a cartridge to form a process cartridge 7.

The photosensitive drums 1 will be described in detail below.

The photosensitive drum 1 is constituted by coating an organic photoconductive layer (OPC photosensitive member) on the outer peripheral surface of an aluminum cylinder having a diameter of 30 mm, for example. Photoconductor drum 1
Has both ends rotatably supported by support members, and is driven to rotate counterclockwise by transmitting a driving force from a drive motor (not shown) to one end.

As the charging device 2, a contact charging type device can be used. The charging member is a conductive roller formed in the shape of a roller. The roller is brought into contact with the surface of the photosensitive drum 1 and a charging bias voltage is applied to the roller to make the surface of the photosensitive drum 1 uniform. It is to be charged.

The scanner unit 3 is arranged substantially in the horizontal direction of the photosensitive drum 1, and a polygon mirror 9 in which image light corresponding to an image signal is rotated at high speed by a scanner motor (not shown) by a laser diode (not shown).
(9a, 9b, 9c, 9d) is irradiated. The image light reflected by the polygon mirror 9 is formed by the imaging lens 10 (10a, 10a).
b, 10c, 10d), the surface of the charged photosensitive drum 1 is selectively exposed to form an electrostatic latent image. Further, as shown in FIG. 5, the scanner unit 3 is formed longer than the pitch between the left and right side plates in the longitudinal direction,
The protrusion 33 is attached so as to project outward from the opening hole 35 of the side plate 32. The pressing method of the scanner unit at that time is about 45 ° downward by the compression spring 36 by about 1 degree.
Pressed with 0N force. As a result, it is surely pressed against the abutment and positioned.

The developing unit 4 is composed of a toner container 41 (41a, 41b, 41c, 41d) containing toners of yellow, magenta, cyan and black, respectively, and the toner in the toner container 41 is fed by a feeding mechanism 42. The toner is fed to the toner supply roller 43, and the toner is applied to the outer circumference of the developing roller 40 which rotates clockwise in the figure by the toner supplying roller 43 which rotates clockwise in FIG. 2 and the developing blade 44 which is pressed against the outer circumference of the developing roller 40. Moreover, the toner is charged.

By applying a developing bias to the developing roller 40 facing the photosensitive drum 1 on which the latent image is formed, toner development is performed on the photosensitive drum 1 according to the latent image.

All the photosensitive drums 1a, 1b, 1c,
An electrostatic transfer belt 11 is disposed so as to face 1d and to circulate so as to come into contact therewith. The electrostatic transfer belt 11 is 10 ¹¹ to 10 ¹⁴
It is composed of a film-like member having a volume specific resistance of Ω · cm and a thickness of about 150 μm. This electrostatic transfer belt 11
Is vertically supported by rollers with four axes, and electrostatically adsorbs the transfer material S on the outer peripheral surface on the left side in the figure, and moves in a circulating manner so as to bring the transfer material S into contact with the photosensitive drum 1. As a result, the transfer material S is conveyed to the transfer position by the electrostatic transfer belt 11, and the toner image on the photosensitive drum 1 is transferred.

Abutting on the inside of the electrostatic transfer belt 11, 4
Transfer rollers 12 (12a, 12b, 12c, 12d) are arranged in parallel at positions facing the respective photosensitive drums 1a, 1b, 1c, 1d. Positive charges are applied from the transfer roller 12 to the transfer material S via the electrostatic transfer belt 11, and an electric field generated by the charges causes the transfer material S in contact with the photosensitive material drum 1 to be transferred onto the photosensitive material drum 1. A negative toner image is transferred.

The electrostatic transfer belt 11 is a belt having a peripheral length of about 700 mm and a thickness of 150 μm, and is stretched by four rollers of a driving roller 13, driven rollers 14a and 14b, and a tension roller 15 in the direction of the arrow in the figure. Rotate. This allows
The toner image is transferred while the above-described electrostatic transfer belt 11 circulates and the transfer material S is conveyed from the driven roller 14a side to the drive roller 13 side.

The feeding section 16 feeds and conveys the transfer material S to the image forming section, and a plurality of transfer materials S are fed to the feeding cassette.
It is stored in 17. At the time of image formation, the feeding roller 18 (half-moon roller) and the registration roller pair 19 are driven and rotated in accordance with the image forming operation to separate and feed the transfer materials S in the feeding cassette 17 one by one, and at the end of the transfer material S. Is a pair of registration rollers
After stopping at 19 and temporarily forming a loop, the rotation of the electrostatic transfer belt 11 and the image writing position are synchronized with each other, and the registration roller pair 19 feeds the electrostatic transfer belt 11.

The fixing unit 20 is for fixing the toner images of a plurality of colors transferred onto the transfer material S, and includes a rotating heating roller 21a and a pressurizing member which is in pressure contact with the heating roller 21a to apply heat and pressure to the transfer material S. It consists of a roller 21b.

That is, the transfer material S onto which the toner image on the photosensitive drum 1 has been transferred is conveyed by the fixing roller pair 21 when passing through the fixing section 20, and is given heat and pressure by the fixing roller pair 21. As a result, the toner images of a plurality of colors are fixed on the surface of the transfer material S.

In the image forming operation, the process cartridges 7a, 7b, 7c and 7d are sequentially driven at the recording timing, and the photosensitive drum 1 is driven in response to the driving.
a, 1b, 1c, and 1d are rotationally driven counterclockwise. Then, the scanner unit 3 corresponding to each process cartridge 7 is sequentially driven. By this driving, the charging roller 2 applies a uniform electric charge to the peripheral surface of the photoconductor drum 1, and the scanner unit 3 moves to the photoconductor drum 1 thereof.
The peripheral surface is exposed according to an image signal to form an electrostatic latent image on the peripheral surface of the photosensitive drum 1. The developing roller 40 in the developing unit 4 transfers toner to the low potential portion of the electrostatic latent image to form (develop) a toner image on the peripheral surface of the photosensitive drum 1.

At the timing when the leading edge of the toner image formed on the peripheral surface of the photosensitive drum 1a on the most upstream side in the conveying direction of the transfer material S is rotatably conveyed to a point facing the electrostatic transfer belt 11,
The registration roller pair 19 starts rotating and feeds the transfer material S to the electrostatic transfer belt 11 so that the recording start position of the transfer material S coincides with the facing point.

The transfer material S is sandwiched between the electrostatic attraction roller 22 and the electrostatic transfer belt 11 so that the electrostatic transfer belt 11 is held.
Of the dielectric material of the transfer material S, which is a dielectric, and the dielectric layer of the electrostatic transfer belt 11 by applying a voltage between the electrostatic transfer belt 11 and the electrostatic attraction roller 22 while being pressed against the outer periphery of the electrostatic transfer belt 11. Then, the transfer material is configured to be electrostatically attracted to the outer periphery of the electrostatic transfer belt 11. As a result, the transfer material S is stably attracted to the electrostatic transfer belt 11 and is conveyed to the most downstream transfer unit.

While being conveyed in this way, the transfer material S sequentially transfers the toner images on the photosensitive drums 1 by the electric field formed between the photosensitive drums 1 and the transfer roller 12.

The transfer material S on which the four color toner images have been transferred is
The curvature is separated from the electrostatic transfer belt 11 by the curvature of the belt driving roller 13 and is carried into the fixing unit 20. The transfer material S has a pair of discharge rollers after the toner image is heat-fixed by the fixing unit 20.
By 23, the image is discharged from the discharge unit 24 to the outside of the main body with the image surface facing down.

[Process Cartridge] The process cartridge will be described in detail with reference to FIGS. 2 and 3 show a process cartridge 7 containing toner.
2 shows a main cross section and a perspective view of FIG. In addition, yellow,
The magenta, cyan, and black process cartridges 7a, 7b, 7c, and 7d have the same configuration.

The process cartridge 7 is a drum-shaped electrophotographic photosensitive member which is an image bearing member, that is, the photosensitive drum 1.
A photosensitive drum unit 50 having a charging means and a cleaning means, and a developing unit 4 having a developing roller 40 which is a developing means for developing an electrostatic latent image on the photosensitive drum 1.

In the photoconductor drum unit 50, the photoconductor drum 1 has a cleaning frame 51 via bearings 31 (31a, 31b).
Is rotatably attached to. On the periphery of the photosensitive drum 1, a primary charging unit 2 for uniformly charging the surface of the photosensitive drum 1 and a cleaning blade 60 for removing the developer (toner) remaining on the photosensitive drum.
Are arranged. In the vicinity of the cleaning blade 60,
A toner feeding mechanism 52 is provided, and the toner feeding mechanism 52 transmits the driving force of a driving motor (not shown) to one end of the rear side in the drawing, so that the photosensitive drum 1 is rotated counterclockwise in the drawing in accordance with an image forming operation. It is driven to rotate. Then, the residual toner removed from the surface of the photosensitive drum 1 by the cleaning blade 60 is sequentially fed by the toner feeding mechanism 52 to the waste toner chamber 53 provided behind the cleaning frame.

The developing unit 4 comprises a developing roller 40 which contacts the photosensitive drum 1 and rotates in the direction of the arrow Y, a toner container 41 containing toner and a developing frame 45. The developing roller 40 is rotatably supported by the developing frame 45 via a bearing member, and on the periphery of the developing roller 40, a toner supply roller 43 and a developing blade that come into contact with the developing roller 40 and rotate in the arrow Z direction. 44 are arranged respectively. Further, in the toner container 41, a feeding mechanism 42 for stirring the contained toner and conveying it to the toner supply roller 43 is provided.

The developing unit 4 is the developing unit 4
Has a suspension structure in which the entire developing unit 4 is swingably supported by the pin 49a with respect to the photosensitive drum unit 50 around the support shafts 49 provided on the bearing members 47 and 48 attached to both ends of the developing unit 4, respectively. There is. In the state where the developing unit 4 is the process cartridge 7 alone (not mounted in the printer body), the developing unit 40 is pressed by the pressing spring 54 so that the developing roller 40 contacts the photosensitive drum 1 due to the rotation moment about the support shaft 49. 4 is always energized. Further, in the toner container 41 of the developing unit 4,
A rib 46 for contacting a separating means (described later) of the printer main body A when separating the developing roller 40 from the photosensitive drum 1.
Are provided integrally.

[Drive] Next, the process cartridge 7
The operation mechanism when the printer is mounted on the printer main body A will be described. Note that, in FIG. 4, in order to explain the configuration in an easy-to-understand manner, the process cartridge 7 (see FIG. 2) in which the charging unit 2, the developing unit 4, and the cleaning device 6 are integrally configured is configured by only the photosensitive drum 1 and the bearing 31. It is shown briefly.

As described above, the process cartridge 7
In the single unit state, the developing roller 40 is always in contact with the photosensitive drum 1 as shown in FIG. The process cartridge 7 is attached to the printer main body A by inserting a bearing 31 for supporting the photosensitive drum 1 along the first guide groove 34 from the direction of the arrow as shown in FIG. Then, as shown in FIG. 6, the bearing 31 is pressed against the abutting surfaces 37 and 38 of the guide groove 34 to determine the position of the process cartridge 7.

As shown in FIG. 5, a shaft 39 is caulked to the left and right side plates 32, a torsion coil spring 30 is supported by the shaft 39, and an end portion 30a thereof is fitted into a hole 32a of the left and right side plates 32 and fixed. ing. In the state where the process cartridge 7 is not provided, the torsion coil spring 30 is restricted in the rotational direction by the bent and raised 32b from the left and right side plates 32. When the process cartridge 7 is inserted, the torsion coil spring
30 rotates counterclockwise against its force,
When it has passed over 31, it is positioned as shown in FIG. 5 and presses the process cartridge 7 into the printer body with a force of about 10 N in the direction of the arrow.

At this time, on the rear side of the printer body A in the insertion direction of the process cartridge 7, as shown in FIGS. 1, 7, and 8, the developing roller 40 is resisted against the urging force of the developing unit 4.
A separating plate 80 is arranged as a separating means for separating the photosensitive drum 1 from the photosensitive drum 1. Developing units 4 (4a, 4b, 4) for yellow, magenta, cyan, and black
(c, 4d) provided with spacers (80a, 80b, 80c, 80d) for pushing up ribs 46a, 46b, 46c, 46d provided on (c, 4d)
Are provided respectively.

The cam 93 is rotated by the driving means shown in FIG. 9, and the separating plate 80 is pushed up by the cam 93, and the separating position for separating the developing roller 40 from the photosensitive drum 1 and the separating plate by the cam 93. It is provided so as to be movable to a developing position where the developing roller 40 is brought into contact with the photosensitive drum 1 in a state where the push-up of 80 is released. Then, only when the developing operation is performed, the push-up of the spacing plate 80 is released to move the developing unit 4 to the developing position.

Here, by limiting the operation mode of pushing up and releasing the spacing plate 80, the structure can be made relatively simple. That is, the stand-by state in which the separating plates 80 for all colors of yellow, magenta, cyan, and black are pushed up (FIG. 1), and the full-color state in which the pushing-up of the separating plate 80 for all colors of yellow, magenta, cyan, and black is released (FIG. 7). , And a monocolor state (FIG. 8) in which only the three colors of yellow, magenta, and cyan are pushed up by the spacing plate 80.

In FIG. 9, the spacing plate is 80d for black.
And 80a, 80b, 80c are integrated into two types, that is, 80z for color, and the cam 93 for moving them has two types of profiles corresponding to the respective spacing plates, so that the above-mentioned mode switching can be performed. .

The drive device for driving the cartridge is shown in FIG.
Drive motor 100 provided for each color such as 0, a series 101 for driving the photosensitive drum 1 and a developing roller 40.
It is branched to the series 102 which drives the clutch C on the motor 100 side.
L is provided so that the rotation stop of the developing roller 40 can be switched when the photosensitive drum 1 rotates once.

With this configuration, the driving of the photosensitive drums 1 for the respective colors can be independently controlled, and therefore it is possible to take control to reduce the color misregistration, which is always a problem in the inline full-color image forming apparatus. Further, it is not necessary to provide a separate motor for driving the development, and the cost can be suppressed.

Next, the details of the clutch CL of the drive device will be described.
This will be described with reference to FIG.

The gear 111, which is a driving component that meshes with the motor 100, is rotatable and axially positioned with respect to the driven rotary shaft 118 by a fixing member (not shown). The inner side of the gear 111 is largely hollowed out, the inner circumference of the sliding boss 111a near the center serves as a positioning and sliding surface for the driven rotary shaft 118, and the outer circumference positions and slides the driving side engaging component 113. It becomes a face. Similarly, there are four detents 111b near the outer circumference inside the gear 111.
There are 13 detents.

The driving side engaging component 113 has a gear whose inner peripheral surface 113a is a gear.
Sliding boss 111a is slidably supported by fitting with the outer peripheral portion of the boss 111a, and at the same time, a rotation stopper provided on the outer peripheral portion.
The 113b meshes with the detent 111b of the gear 111 to rotate the same as the gear 111. On the other hand, the engaging part 113 has four protrusions 113c, which are protrusions of the engaging part 114 on the driven side.
Rotation can be transmitted by engaging with 114c.

The drive transmitting surface of the protrusion 113c is formed so as to be inclined in the direction in which it bites into the mating component by rotation. As a result, even if the clutch is engaged during rotation, the clutches are surely engaged with each other, and tooth skipping does not occur even when a large torque is applied. Also, by connecting the drive transmission surfaces with a gentle slope,
Even when the clutch is engaged during rotation, it can be engaged smoothly.

On the driven-side end surface of the driving-side engaging part 113,
It has a sliding portion 113d that rotates and slides with a release member 115 described later. Further, the engaging part 113 is always biased toward the driven side engaging part 114 by the coil spring 112 as an elastic member. Since the parts in contact with both ends of the coil spring 112 rotate in the same direction, problems with the end sliding of the spring and malfunctions due to changes in the winding diameter do not occur.

In the driven side engaging component 114, the rotary shaft 118 and the parallel pin 119 are fitted and fixed to the inner peripheral surface 114a and the groove 114b. Further, there are four protrusions 114c, and when these engage with the protrusions 113c of the driven side engaging component 113, the rotation is transmitted. The drive transmission surface of the protrusion 114c is inclined in the same direction as the mating component 113c, and the drive transmission surfaces are connected by a gentle slope.

Drive side engaging member 113, driven side engaging member 114,
The coil spring 112 is included inside the gear 111. This makes it possible to make efficient use of space and make it compact, and since the driving force transmitted from the tooth surface is transmitted to the inside as it is, twisting and tilting forces do not occur in the engaging parts,
It is easy to secure the strength of parts and it is possible to transmit a large torque.

The rotary shaft 118 is rotatably supported by the frame 120 of the drive unit via the bearing member 117, and transmits the rotation from the gear 121 fixed at the end to the developing drive unit of the cartridge. The bearing member 117 is fixed to the frame 120 of the drive unit, and has two outer peripheral parts, a sliding part 117a which has a detent and a positioning function and is slidable in the axial direction, and a cylindrical surface 117b which rotates and slides. It has a sliding part.

It is the lever member 116 that fits and rotates with the sliding portion 117b of the bearing member 117, and the lever portion 116a is operated by the switching member 91 described later. The lever member 116 has a cam portion 116c, which abuts on the cam portion 115c of the release member 115 to control the axial position. Also, the cam portions 115c and 116c
Are symmetric with respect to the center of rotation. As a result, it is possible to prevent a malfunction or an increase in operation resistance due to tilting of the release member 115.

The releasing member 115 has an inner sliding portion 115a fitted to the sliding portion 117a of the bearing member 117, is restricted in rotation, and is supported movably in the axial direction. The cam portion 115c has a shape corresponding to the cam portion 117c of the lever. The cam portion 115c abuts on the cam portion 117c to determine the axial position, and at the same time, the sliding portion 115b on the side opposite to the cam abuts on the drive side engaging part 113. You will come in contact with them to determine the position.

That is, in the state where the cam portion 116c of the lever member 116 and the cam portion 115c of the releasing member 115 are aligned with each other, the releasing member 115 is pushed out toward the gear 111, and the sliding portion 115b is driven. The drive side engaging member 113 is opposed to the spring 112 by coming into contact with the sliding portion 113d of the engaging member 113 and the driven side engaging member 11
It is separated from 4, and the so-called clutch is disengaged.

When the motor 100 rotates in this state, the sliding portion 1
Although 13d and 115b slide, the clutch is disengaged and there is no load on the driven side, so loss due to sliding resistance is not a problem.

On the other hand, the lever member 116 is turned to rotate the lever member 1
In a state where the cam portion 116 c of 16 and the cam portion 115 c of the releasing member 115 are aligned with each other, the releasing member 115 moves in the direction of the driven gear 121 and the driving side engaging member 113 causes the spring 112 to move.
Is pressed by the elastic force of, and engages with the driven side engaging member 114, the clutch is engaged and the rotation is transmitted. When the engaging members are completely engaged, a gap is created between the driving side engaging member 113 and the releasing member 115 and the lever member 116, so that the sliding portions 113d and 115b are almost slid. No load is generated and there is almost no decrease in efficiency.

The clutch CL may have a structure in which the driving side and the driven side are opposite to each other.

As shown in FIGS. 12 (b) and 13 (b), the cam shapes of the lever member 116 and the release member 115 are different for black and for other colors. That is, the black cam has a Mt. Fuji shape, and at the home position, the peaks of the peaks come into contact with each other to disengage the clutch, and the clutch is engaged no matter which direction the lever is turned. The cam shapes of other colors have a slope similar to that for black on one side, but a flat portion having the same height as the apex on the other side.

At the home position, the clutch is disengaged. If the lever is turned in the direction in which the peak and valley of the cam come into contact with each other, the clutch is connected (FIG. 12 (b)), but the clutch is disengaged even if it is turned to the opposite side. Up to (Fig. 13
(B)).

With this configuration, it is possible to easily set the full-color printing state in which all the clutches CL are connected and the mono-color state in which only the black clutch CLd is connected, with the home position as a reference.

As shown in FIG. 11, the clutch CL for developing drive and the cam 93 for moving the spacing plate 80 can be operated by vertically moving the switching member 91 by one motor 90. Switching member
The load resistance when operating 91 is maximum when all four clutches CL are disengaged after the completion of full-color printing.

On the other hand, by providing the spring 122 for pulling the switching member 91 downward as shown in FIG.
At the end of full-color printing, the switching member 91 moving to the uppermost portion is pulled down by a strong spring force, and the load when the clutch CL of all colors is disengaged can be reduced. This spring force is also effective in reducing the load when separating the developing rollers for all colors by rotating the separating cam 93 at the end of printing.

On the other hand, at the end of the mono-color printing, as shown in FIG.
As shown in FIG. 3 (a), the spring force applied to the switching member 91 moving to the lowermost part is small, so the load increase when the black clutch CLd is disengaged is small. Furthermore, by setting the spring so that the spring force becomes zero near the home position, it is possible to make effective settings for both the clutches CL of all colors and the clutches of only black.

Further, as shown in FIG. 12B, etc., the load is made uniform by making the slope of the cam used when disengaging the clutches CL of all colors less than the slope when disengaging only the black clutch CLd. Can be distributed to

[Operation] When the process cartridge 7 is attached to the printer main body A, the developing drive and separating device on the main body side is at the home position, and the switching member 91 is accurately positioned by a sensor (not shown). . At this time, the separating plates 80 for all colors of yellow, magenta, cyan, and black are pushed up, and the ribs 46 provided on the developing unit 4 ride on the separating plate 80 along with the inserting operation of the process cartridge 7. The developing roller 40 is separated from the photosensitive drum 1 by a predetermined gap.

This separated state is always maintained when the power is off and the developing is not performed. Therefore, even if the process cartridge 7 is not used for a long time with the process cartridge 7 mounted, the developing roller 40 is always separated from the photosensitive drum 1, so that the developing roller 40 is kept in contact with the photosensitive drum 1 for a long time. By doing so, it is possible to reliably prevent permanent deformation of the roller layer.

The recording operation will be described separately for full-color printing and mono-color printing.

In the case of full-color printing, when the recording operation is started by the print signal, all the motors 100 for driving the process cartridge and the driving motors for the transfer belt rotate. At this time, the switching member 91 is at the home position, all the clutches CL are disengaged, and all the developing rollers 40 do not rotate.

Next, as shown in FIG. 12 (a), the stepping motor 90 rotates clockwise to the first stage in the drawing, and the switching member 91 is raised to the first stage in the upward direction, whereby all the clutches CL are cleared. The lever member 116 of FIG. 12 rotates by the angle θ1, and all the releasing members 115 and the driving side engaging members 113 move to the right side in the figure as shown in FIG.
All the developing rollers 40 rotate by engaging 14 and connecting the clutch.

Here, when the cartridge drive motor 100 is rotated after the stepping motor 90 is rotated to the first stage, the impact load when the clutch is engaged is reduced, but the purpose is to shorten the rotation time of the developing roller 40. It is disadvantageous.

Next, when the stepping motor 90 rotates clockwise to the second stage, the switching member 91 moves up to the second stage in the upward direction, and the lever member 116 rotates to the angle θ2 (not shown). At this time, since the position of the releasing member 115 is the position for maintaining the engagement between the driving side engaging component 113 and the engaging component 114 (FIG. 12C), all the developing rollers 40 are still rotating. On the other hand, the separating cam 93 is rotated to release the push-up of the color and black separating plates 80z and 80d, and all the developing rollers 40 come into contact with the photosensitive drum 1 to be in a recordable state.

After the end of recording, the developing roller 40 is separated from the photosensitive drum 1 by returning the stepping motor 90 to the first stage. Then, by rotating the stepping motor 90 back to the initial state, all clutches CL are
To stop the rotation of the developing roller 40 and stop the cartridge driving motor 100 and the transfer belt driving roller. The stepping motor 90 may be rotated from the first stage to the initial state after stopping the cartridge driving motor 100 and the transfer belt driving roller.

In the case of monocolor printing, when the recording operation is started by the print signal, all the motors 100 for driving the process cartridge and the driving motors for the transfer belt rotate. At this time, the developing roller 40 does not rotate because all the clutches CL are disengaged.

Next, as shown in FIG. 13A, when the stepping motor 90 rotates counterclockwise in the figure to the first stage and the switching member 91 is lowered to the first stage in the downward direction, all the clutches CL are cleared. The lever member 116 of FIG.
As shown in 3 (b), only the black clutch CLd is connected and the other clutches CLa to CLc remain disengaged, so only the black developing roller rotates.

If the cartridge driving motor 100 is rotated after the stepping motor 90 is rotated to the first stage, the impact load when the clutch is engaged is reduced, but for the purpose of shortening the rotation time of the developing roller. Is disadvantageous.

Next, when the stepping motor 90 rotates counterclockwise to the second stage, the switching member 91 moves downward in the second direction.
Then, the lever member 116 is rotated to an angle θ4 (not shown). At this time, as shown in FIG.
Since the position of the black releasing member 115 is maintained in the state of the first stage, the black developing roller 40 is still rotating. On the other hand, the separating cam 93 rotates to release the push-up of the black separating plate 80d, and the black developing roller 40 comes into contact with the photosensitive drum 1 to enable recording.

After completion of recording, the developing roller 40 is separated from the photosensitive drum 1 by returning the stepping motor 90 to the first stage. Then, the rotation of the developing roller 40 is stopped by rotating the stepping motor 90 to the initial state, and the cartridge driving motor 100 and the transfer belt driving roller are stopped. The stepping motor 90
The rotation from step 1 to the initial state may be performed after stopping the cartridge driving motor 100 and the transfer belt driving roller.

In the process of forming an image as described above, before the electrostatic latent image is formed by the scanner unit 3, a pre-rotation is performed in order to apply a uniform charge to the peripheral surface of the photosensitive drum 1. Be seen. After developing the toner image, a post-rotation process or the like is performed in order to eliminate the electric potential on the peripheral surface of the photosensitive drum 1. During the pre-rotation and the post-rotation, the developing roller 40 is separated from the photosensitive drum,
The toner is not wasted due to fogging and the like, and it is possible to reduce the abrasion of the photosensitive drum 1 with the developing roller 40 and the abrasion of the surface layer.

In addition, a stand-by state in which all color separation plates 80 are pushed up (FIG. 1), a full color state in which all color separation plates 80 are released from pushing up (FIG. 7), only three colors of yellow, magenta, and cyan are separated. By consolidating the modes by making it possible to select three states of the monochromatic state (FIG. 8) in which the plate 80 is pushed up, it is possible to simplify the component configuration and control.

Further, by applying an elastic force to the switching member 91 by the spring 122 so as to urge the plurality of clutches CL in the releasing direction, the operating torque is reduced, and electric parts such as motors and mechanical parts are switched. Cost reduction is possible.

[0082]

As described above, the clutch for controlling the rotation and stop of the developing roller is provided, and the clutch has its axial position rotatably regulated with respect to the driven side rotation shaft, and the motor side. A drive component that transmits the drive from the drive component, a drive-side engagement component that rotates in the same direction as the drive component and is movable in the axial direction, and a driven-side rotation shaft that is fixed and engages with the drive-side engagement component. Driven side engaging parts, an elastic member for urging the driving side engaging parts in a direction to engage the driven side engaging parts, and a control means for moving the driving side engaging parts in the axial direction to engage and release. And the drive side engagement component and the driven side engagement component,
It has a plurality of drive transmission surfaces that are inclined in a direction in which they engage each other when engaged, and the drive transmission surfaces are arranged symmetrically with respect to the center of rotation. As a result, it is possible to obtain a drive device that employs a small-sized and low-cost mechanical clutch that can reliably interrupt a relatively large torque even when the drive side is rotating.

Further, the control means includes a lever member that rotates around a rotation axis, and the lever member has a plurality of cam portions that are symmetrical with respect to a rotation center, and the lever is a switching member that moves in the axial direction. The clutch is engaged and disengaged by rotating the member and moving the drive-side engaging component or the driven-side engaging component in the axial direction by the cam portion. Thereby, the control of the clutch operation can be simplified.

Further, the cam shapes of the black cartridge drive section and the other color cartridge drive sections are such that the slope of the cam used when disengaging the clutches of all colors is less than the slope when disengaging only the black clutch. . As a result, the load distribution can be optimized and the cost of electric parts can be reduced.

In particular, by installing a plurality of driving devices in the color image forming apparatus, it is possible to provide an inline color image forming apparatus of high quality and low cost.

[Brief description of drawings]

FIG. 1 is a sectional view of a color image forming apparatus according to an embodiment.

FIG. 2 is a sectional view of a process cartridge.

FIG. 3 is a perspective view of a process cartridge.

FIG. 4 is a perspective view showing a method of mounting the process cartridge on the color image forming apparatus.

FIG. 5 is a partial cross-sectional view showing a positioning portion of the process cartridge with respect to the color image forming apparatus.

FIG. 6 is a partial cross-sectional view showing a positioning portion of the process cartridge with respect to the color image forming apparatus.

FIG. 7 is a cross-sectional view showing a separation release state of the process cartridge.

FIG. 8 is a process cartridge for releasing black separation,
It is sectional drawing which shows another color separation state.

FIG. 9 is a perspective view showing an operation switching mechanism.

FIG. 10 is a perspective view of a drive unit that drives a cartridge.

FIG. 11 is a perspective view showing a mechanical clutch.

FIG. 12 is a schematic diagram showing a state of a clutch during full-color recording.

FIG. 13 is a schematic diagram showing a state of a clutch at the time of monochrome recording.

[Explanation of symbols]

A ... Full color laser beam printer CL ... Clutch S ... Transfer material 1 ... Photosensitive drum 2 ... Charging device 3 ... Scanner unit 4 ... Development unit 5 ... Electrostatic transfer device 6 ... Cleaning device 7 ... Process cartridge 9 ... Polygon mirror 10… Imaging lens 11… Electrostatic transfer belt 12… Transfer roller 13… Drive roller 14a, 14b ... driven roller 15… Tension roller 16… Feeding department 17… Feed cassette 18… Feeding roller 19… Registration roller pair 20 ... Fixing unit 21a ... Heating roller 21b ... Pressure roller 22… Electrostatic attraction roller 23… Ejection roller pair 24… Ejector 30… torsion coil spring 30a ... end 31… Bearings 32… Side plate 32a ... hole 32b ... Bending and raising 33 ... Protrusion 34… Guide groove 35… Open hole 36… Compression spring 37… Abutting surface 38… Abutting surface 39… Axis 40 ... Developing roller 41… Toner container 42 ... Feeding mechanism 43… Toner supply roller 44… Development blade 45 ... Development frame 46… Ribs 47, 48 ... Bearing members 49… Support shaft 49a ... pin 50 ... Photosensitive drum unit 51… Cleaning frame 52 Toner feeding mechanism 53… Waste Toner Room 54 ... Pressure spring 60… Cleaning blade 80 ... Spacer 80d ... For black 80z ... for color 91… Switching member 93 ... cam 100 ... motor 101, 102 ... Series 111… Gears 111a… Sliding boss 111b ... Detent 112… Coil spring 113… Drive side engaging parts 113a ... Inner surface 113c ... Protrusion 113d… Sliding part 114… Engagement parts 114a ... Inner surface 114b ... Groove 114c ... Protrusion 115… Release member 115b ... Sliding part 115c ... Cam section 116… Lever member 116a ... Lever part 116c ... Cam section 117… Bearing members 117a ... Sliding part 117b ... Cylindrical surface 118… Rotation axis 119… Parallel pin 120… frame 121… Gears 122… Spring

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/01 113 G03G 15/08 507H 21/18 15/00 556 F term (reference) 2H030 AA06 AA07 AB02 AD08 AD17 BB02 BB33 2H071 AA03 BA05 BA13 BA20 BA27 CA01 CA02 CA05 DA08 DA13 DA15 DA26 DA31 EA18 2H077 AB03 AB14 AC04 AD02 AD06 AD13 AE03 BA01 BA03 BA04 BA07 BA09 DA05 DA82 DB14 DB18 DB25 EA14 GA13 GA15 CC03 DA08 CC02 DA08 CC02 DA08 CC02

Claims (9)

[Claims] 1. A drive unit used in a color image forming apparatus, comprising a plurality of process cartridges each having an electrophotographic photosensitive member and a developing unit and having a separating unit for separating the electrophotographic photosensitive member and the developing roller, wherein the developing roller And a drive component for controlling the rotation and stop of the drive mechanism, the clutch having a rotationally regulated axial position with respect to the driven rotation shaft and transmitting drive from the motor side; A drive-side engaging component that rotates in the same direction as that of the driven-side engaging component that is movable in the axial direction; a driven-side engaging component that is fixed to the driven-side rotating shaft and that engages with the driving-side engaging component; An elastic member for urging the driven side engaging part in a direction to engage with the driven side engaging part; and a control means for moving the driving side engaging part in the axial direction to engage and disengage the driving side engaging part and the driven side engaging part. When the engaging parts are engaged, Has a plurality of drive transmission surface tilted in the direction of biting you are, it drives the drive transmission surface is characterized by being arranged symmetrically with respect to the rotation center. 2. A drive unit used in a color image forming apparatus, comprising a plurality of process cartridges each having an electrophotographic photosensitive member and a developing unit, and having a separating unit for separating the electrophotographic photosensitive member and the developing roller. And a clutch for controlling rotation and stop of the driving side, the clutch being fixed to a rotation shaft on the driving side, the driving side engaging part engaging with the driven side engaging part, and the driving side engaging part being movable in the axial direction. The driven side engaging part that rotates by engaging with the engaging part, the part that rotates in the same direction as the driven side engaging part, the position in the axial direction is restricted, and the rotation is transmitted, and the driven side engaging part. The drive-side engaging component and the driven side have an elastic member that urges the drive-side engaging component in a direction to engage with the drive-side engaging component, and a control unit that axially moves the driven-side engaging component to engage and disengage. When the engaging parts engage, they engage each other. More has a drive transmission surface tilted in the direction of biting into the drive device the drive transmission surface is characterized by being arranged symmetrically with respect to the rotation center. 3. A system in which one motor is provided for each process cartridge of each color, and each motor branches into a series for driving an electrophotographic photosensitive member and a series for driving a developing roller, and a series for driving a developing roller. The drive device according to claim 1 or 2, wherein the clutch is used for the drive. 4. The drive device according to claim 1, wherein the drive component is a gear, and the drive-side engagement component and the driven-side engagement component are contained in the gear. 5. The control means includes a lever member that rotates around a rotation axis, the lever member having a plurality of cam portions that are symmetrical with respect to a rotation center, and the lever is a switching member that moves in the axial direction. 3. The drive according to claim 1, wherein the clutch is engaged and disengaged by rotating a member and axially moving the drive-side engagement component or the driven-side engagement component by the cam portion. apparatus. 6. The drive device according to claim 5, wherein the switching member controls the plurality of clutches by rotating the plurality of lever members used in the process cartridge of each color. 7. A full-color print state in which all color clutches are connected, a standby state in which all color clutches are disengaged, and a black color only. 7. The drive device according to claim 6, wherein it is possible to switch between three states of a mono-color state in which a clutch is connected. 8. The cam shapes of the black cartridge drive section and the other color cartridge drive sections are such that the slope of the cam used when disengaging the clutches of all colors is looser than the slope when disengaging only the black clutch. The drive device according to claim 7, wherein: 8. The drive device according to claim 6, wherein one elastic member is added to the switching member to urge the plurality of clutches in a releasing direction. 9. A color image forming apparatus comprising the driving device according to claim 1.