JP2001013848A - Image forming unit and color electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming unit that hardly give the rotation of a photoreceptor a disturbance, that can keep the contact pressure of the photoreceptor and a developing roller small and uniform, and that can form a uniform image without irregularity with a simple constitution. SOLUTION: The image forming unit is constituted of a photoreceptor unit 37 which has the photoreceptor 30 with an electrostatic latent image formed on its surface and an electrifying means electrifying the photoreceptor 30, and a developing unit 35 which has developer and the developing roller 31 carrying the developer to a developing area and develops the electrostatic latent image. The roller 31 is rotated and driven by a developing and driving main body gear 62, a rocking gear 94 attached to a main body side wall, through a developing roller gear 96 fixed on the roller 31. The unit 35 is supported on the unit 37 by a fulcrum pin 90 so that it can rock. A meshed position of the gears 94 and 62 is nearly the center of the pin 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color printer,
The present invention relates to a color image forming apparatus applicable to a color copying machine, a color facsimile, and the like, and an image forming unit used for the same, and more particularly, to a color electrophotographic apparatus for forming a color image using an electrophotographic method and an image forming unit used for the same.

[0002]

2. Description of the Related Art A conventional color image forming apparatus, in particular, an image forming unit used for the same is disclosed in
One disclosed in Japanese Patent No. 93141 is known.

Hereinafter, a conventional image forming unit will be described with reference to FIG. In FIG. 9, reference numeral 200 denotes a photoreceptor;
Denotes a developing roller, and 203 denotes a charger. A photoconductor unit 205 supports the photoconductor 200 and the charger 203 and is integrated with a cleaner case. A development unit 207 supports the developing roller 201 and is integrated with the toner case. The developing unit 207 is rotatably connected to the photoconductor unit 205 by a fulcrum shaft 210. On the opposite side of the fulcrum shaft 210 from the photoconductor 200, the developing unit 207 and the photoconductor unit 205 are disposed. A compression spring 213 is provided in a state of being sandwiched. As a result, the photoconductor 200 and the developing roller 201 are brought into pressure contact with each other.
The developing roller 201 is driven by using the rotational force of the photoconductor 200, and a gear fixed to the photoconductor 200 and a gear (not shown) fixed to the developing roller 201 are connected to each other in the direction of the arrow. It is driven to rotate.

In general, when such an image forming unit is mounted on the main body of an electrophotographic apparatus, the position of the axis of the photoconductor 200 and a part of the photoconductor unit 205 are fixedly supported by the main body of the apparatus. The image is formed by being rotationally driven.

[0005]

In the formation of a color image, in particular, unnecessary disturbance to the photoconductor is reduced as much as possible to improve the rotation accuracy of the photoconductor, and the contact between the developing roller and the photoconductor is reduced. It is necessary to perform the process lightly and uniformly to form a uniform image without unevenness.

However, in the above-described conventional image forming unit, the rotation unevenness of the developing roller is easily transmitted to the photosensitive member, and the rotational driving force received by the developing roller becomes a pressing force against the photosensitive member to contact the photosensitive member. The pressure becomes non-uniform, and the image tends to be uneven.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and has a simple structure that does not easily disturb the rotation of the photosensitive member and reduces the contact pressure between the photosensitive member and the developing roller. It is another object of the present invention to provide an image forming unit capable of maintaining uniformity and forming a uniform image without unevenness, and a high-quality color image forming apparatus using the same.

[0008]

In order to achieve the above object, an image forming unit according to the present invention comprises a photoreceptor unit having a photoreceptor having a surface on which an electrostatic latent image is formed, a developer and An image forming unit comprising: a developing roller that carries a developer in a developing region; and a driving force transmitting unit that rotates the developing roller; and a developing unit that visualizes the electrostatic latent image. The developing unit is swingably supported by the photoconductor unit, and an application point of a force for transmitting a rotational force to the developing unit is provided in the vicinity of a swing center axis of the photoconductor unit and the developing unit. It is characterized by the following. According to the configuration of the image forming unit, the developing unit rotates with respect to the photoconductor unit by the force transmitting the rotational force to the developing unit, and the developing roller is not pressed against the photoconductor. Since the set pressing force can be maintained, the developing roller and the photoconductor can always be brought into contact with each other in a stable state.

In the image forming unit of the present invention, it is preferable that a driving force for rotating the developing roller is provided from outside the image forming unit. According to this preferred example, the photosensitive member is not subjected to a load change caused by driving the developing roller, and the contact pressure of the developing roller with respect to the photosensitive member can be set small. Less susceptible to disturbance,
Stable rotation is ensured. In this case, it is preferable that the electrostatic latent image is visualized by the contact of the developing roller with the photoconductor. In this case, the developing unit is swingably supported by the photoconductor unit on the driving side of the developing unit, and the sliding guide provided on the photoconductor unit on the opposite side. It is preferable that the relative position between the photoconductor and the developing roller is determined. According to this preferred example, the contact between the photoconductor and the developing roller can be kept uniform over the entire surface irrespective of the twist of the housing of each unit (developing unit, photoconductor unit). Also, in this case,
It is preferable that a driven gear, which is driven directly from outside the image forming unit, of the driving force transmitting means for rotating the developing roller is supported so as to be able to swing around the rotation axis of the developing roller. According to this preferred example, it is possible to automatically couple with the developing drive main body gear of the main body only by rotating the carriage of the main body on which the image forming unit is mounted. In this case, the image forming unit further includes a swinging member that swingably supports the driven gear, and the swinging member is provided in the image forming unit when a rotational force is transmitted to the developing roller from outside the image forming unit. It is preferable to lock at the engaged portion. According to this preferred example, since the developing unit does not receive a rotational moment around the engagement portion from outside the developing unit, the photosensitive member and the developing roller can be stably contacted.

In the image forming unit of the present invention, the image forming unit is provided at both ends of the rotating shaft of the photosensitive member, and is provided at an engaging portion supported by the apparatus main body and at a driving force transmitting side of the developing unit. It is preferable that the image forming apparatus further includes a rotation locking portion for performing rotation positioning of the photoconductor around a rotation axis. According to this preferred example, since the image forming unit is supported by the apparatus main body at the three positions of the engagement portion and the rotation locking portion at both ends of the rotation shaft of the photoconductor, the positioning of the photoconductor with respect to the apparatus main body can be performed. This can be performed reliably, and there is no problem that the image forming unit is twisted by receiving the developing driving force, and it is difficult to secure the contact between the photosensitive member and the developing roller. In this case, it is preferable that the rotation locking portion is provided on the photoconductor unit. According to this preferred example, since the rotational force of the entire image forming unit is supported only by the photoconductor unit, the contact state between the photoconductor and the developing roller is not affected. In this case, it is preferable that the rotation locking portion is a fulcrum shaft for swingably supporting the developing unit or a receiving portion of the fulcrum shaft. According to this preferred example, since the carriage on the main body side supports the image forming unit at a position where the developing unit receives an external force,
No excessive twisting force is generated in the image forming unit.

Further, the configuration of the color electrophotographic apparatus according to the present invention comprises a plurality of image forming units each combining a developing unit and a photoreceptor of a different color, and the plurality of image forming units are connected to an image forming position and a retreat position. An image forming unit transferring means for sequentially moving and switching between the image forming unit, a positioning means for positioning the photoconductor at the image forming position, an exposing means for exposing the photoconductor located at the image forming position, and the image forming apparatus. A color image in which a plurality of color toner images are superimposed on the transfer body by successively superimposing the toner images formed by the developing device on the photoreceptor positioned at the formation position and transferring the resultant onto the transfer body A color electrophotographic apparatus comprising: a transfer unit configured to form the image forming unit; and a rotation driving unit configured to rotationally drive the photosensitive member and the transfer unit. Characterized by using the forming unit. According to the configuration of the color electrophotographic apparatus, the photosensitive member can be reliably positioned with a simple configuration, and a high-quality and stable color image that can secure uniform development with a light pressing force can be formed. It is possible to do.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to embodiments.

First, the overall configuration and operation of an image forming unit and a color electrophotographic apparatus using the same according to an embodiment of the present invention will be described with reference to FIGS.

(Image Forming Unit) FIG. 1 is a sectional view showing an image forming unit according to an embodiment of the present invention.

In FIG. 1, reference numeral 30 denotes a photosensitive member;
Reference numeral 35 denotes a developing unit including a developing roller 31, a supply roller 33 for supplying toner, a doctor blade 24 for forming a toner layer, and a toner hopper 39 for storing the toner 32. Reference numeral 36 denotes a rubber cleaning blade for cleaning the toner remaining on the surface of the photoreceptor 30 after transfer, and reference numeral 38 denotes a waste toner case for storing waste toner scraped off by the cleaning blade 36. The photoreceptor unit 37 is configured by attaching the device 34 and the photoreceptor 30. Further, the photoconductor unit 37 and the developing unit 35
Are swingably connected by a fulcrum pin 90 to be integrated, thereby forming the image forming unit 3.
The photoconductor 30, the developing roller 31, and the supply roller 33 are rotatably supported, and rotate in the directions indicated by arrows. The toner 32 is a negatively-charged toner in which a pigment is dispersed in a polyester resin. The toner 32 is supplied from the supply roller 33 to the developing roller 31 through the supply port 25, is thinned by the doctor blade 24, and is supplied to the photoreceptor 30. Then, the electrostatic latent image on the photoconductor 30 is developed.

(Transfer Belt Unit) FIG. 2 is a sectional view showing a color electrophotographic apparatus using an image forming unit according to an embodiment of the present invention.

The transfer belt unit 5 shown in FIG. 2 is for copying the toner image formed on the photoreceptor 30 at the image forming position 10 and retransferring the copied toner image to recording paper. The transfer belt unit 5 includes an intermediate transfer belt 50 and a group of pulleys (a drive pulley 55A, a backup pulley 55B, a guide pulley 55C, a tension pulley 55C) for suspending the intermediate transfer belt 50.
D), a cleaner 51, and a waste toner case 57 for storing waste toner after cleaning.
These are integrated and detachably attached to the apparatus main body 1.

The intermediate transfer belt 50 has a thickness of about 100 μm.
The endless belt-shaped semiconductive (medium resistance) urethane is coated with a fluororesin such as PFA or PTFE, and has a total thickness of 100 to 300 μm. In order to perform A4 size or letter size full color printing, the circumferential length of the intermediate transfer belt 50 is the length in the longitudinal direction of A4 image receiving paper which is the maximum image receiving paper size (2
97 mm).

The cleaner 51 is for cleaning and removing the toner remaining on the intermediate transfer belt 50, and includes a rubber cleaning blade 53 and a screw 52 for conveying the scraped toner to a waste toner case 57. It is configured. The cleaner 51 is provided to prevent the toner image on the intermediate transfer belt 50 from being scraped off while forming a color image on the intermediate transfer belt 50.
It is configured to rotate about the fulcrum 58 and to separate from the intermediate transfer belt 50.

In the pulley group for suspending the intermediate transfer belt 50, a pulley 55A is a drive pulley for driving the intermediate transfer belt 50, and also serves as a backup for the cleaning blade 53. The pulley 55B is a backup pulley for the secondary transfer roller 9 that transfers the toner image on the intermediate transfer belt 50 to recording paper. Pulley 55
C is a guide pulley, which also serves as a roller for applying a primary transfer bias for transferring a toner image from the photoconductor 30 onto the intermediate transfer belt 50. The pulley 55D is a tension pulley that applies tension to the intermediate transfer belt 50. The intermediate transfer belt 50 is connected to these pulleys 5
5A, 55B, 55C, and 55D, and can be rotationally driven by rotation of the drive pulley 55A. Reference numeral 56 denotes a cover for protecting the intermediate transfer belt 50.

(Overall Configuration of Apparatus) In FIG. 2, the right end face is the front face of the apparatus, and a carriage 2 is provided substantially in the center of the apparatus main body 1, a front alligator 1A is provided on the front face, and a top door 17 is provided on the top face.

The carriage 2 has four color (yellow, magenta, cyan, and black) image forming units 3Y and 3Y.
M, 3C and 3Bk are accommodated. The carriage 2 is rotatably supported by a circular tube 21. Thereby, the image forming units 3 can be switched by sequentially moving the photoconductors 30 of the image forming units 3 of each color between the image forming position 10 and the other retreat positions.

The image forming unit 3 is detachably mounted on the apparatus main body 1. When the image forming unit 3 needs to be replaced, the carriage 2 is rotated to mount the image forming unit 3 of the color to be replaced. It can be located below the face door 17 and can be replaced by opening the top door 17.

The image forming operation position of the image forming unit 3 in the carriage 2 is only at the image forming position 10 where the photoreceptor 30 is irradiated with the pixel laser signal light 8 and the transfer belt unit 5 and the photoreceptor 30 are in contact with each other. is there. The image forming unit 3
The image forming position 10 is connected to a drive source and a power supply of the apparatus main body 1, thereby performing an image forming operation. The other positions are the retracted positions, and no image forming units 3 operate in this position.

The front alligator 1A is hinged to the apparatus main body 1 by a hinge shaft 1B, and can be opened by falling to the front. This front alligator 1A has a fixing device 1
5, secondary transfer roller 9, static elimination needle 7, paper guide 13a,
3b, 13c, 13d Front Side and Registration Roller 16
When the front alligator 1A is tilted forward, these components also fall at the same time. For this reason, the front surface of the apparatus main body 1 can be largely released, and the transfer belt unit 5 can be detached from this portion, and the recording paper can be easily removed even in the case of a paper jam.

The transfer belt unit 5 is securely positioned at a predetermined position when the transfer belt unit 5 is mounted on the apparatus main body 1, and the portion facing the image forming position 10 is the photosensitive member 3 of the image forming unit 3.
Touch 0. At the same time, the transfer belt unit 5
Are electrically connected to the main body, and the driving pulley 55A is connected to the driving means on the main body, so that the intermediate transfer belt 50 is in a rotatable state.

The static elimination needle 7 is for preventing the toner image from being disturbed when the recording paper is separated from the intermediate transfer belt 50.

Reference numeral 6 denotes a laser exposure device disposed below the transfer belt unit 5.
Is a semiconductor laser (not shown), a polygon mirror 6
A, a lens system 6B, a first mirror 6C, and the like. The pixel laser signal light 8 corresponding to the time-series electric pixel signal of the image information is transmitted to the yellow image forming unit 3 shown in FIG.
Y photoconductor unit 37 and black image forming unit 3
It passes through the optical path 22 formed between the Bk and the developing unit 35. The pixel laser signal light 8 passes through the exposure window 97 of the circular tube 21, and is fixed to the apparatus main body 1 in the circular tube 21.
The light enters a mirror 98 (which is stationary irrespective of the circular tube 21), is reflected and passes through a gap 33 provided between the photoreceptor unit 37 of the image forming unit 3Y and the developing unit 35 to form an image forming position. The light enters the exposed portion on the left side of the photoconductor 30 located at 10 and scans and exposes the photoconductor 30 in the generatrix direction.

Reference numeral 12 denotes a paper feed unit, 14 denotes a paper feed roller,
16 is a registration roller, 18 is a discharge roller, 13a, 1
Reference numerals 3b, 13c, and 13d denote paper guides that connect between these rollers, the contact point between the intermediate transfer belt 50 and the secondary transfer roller 9, and the fixing device 15.

(Apparatus Operation) Next, a color image forming process will be described.

When the power of the apparatus main body 1 is turned on in a state where the transfer belt unit 5 and the image forming units 3 of the respective colors are mounted at predetermined positions, the temperature of the fixing device 15 rises and the polygon mirror 6A of the laser exposure device 6 Starts spinning,
Preparation is completed. In some cases, immediately after the power is turned on, the initialization mode for maintaining the state of the photoconductor 30 and the intermediate transfer belt 50 may be operated.

When the preparation is completed, first, image formation by the yellow image forming unit 3Y at the image forming position 10 is started. Then, at the same time as the yellow photoconductor 30 connected to the drive source of the apparatus main body 1 starts rotating at the image forming position 10, the developing roller 31, the corona charger 34, and the intermediate transfer belt 50 start to move. The drive pulley 55A is driven from the apparatus main body 1 side, and the frictional force causes the intermediate transfer belt 50 to rotate in the direction of the arrow. Here, the photoconductor 3
The peripheral speed of 0 and the peripheral speed of the intermediate transfer belt 50 are set to be substantially equal. At this time, the secondary transfer roller 9 and the cleaner 51 are separated from the intermediate transfer belt 50.

The corona charger 34 of the surface of the photosensitive member 30
The detection means (not shown) detects the leading position of the intermediate transfer belt 50 in synchronization with the timing at which the uniformly charged portion comes to the exposure position, and synchronizes the image from the laser exposure device 6 with the detection signal. The photoconductor 30 is irradiated with the pixel laser signal light 8 corresponding to the signal. When the uniformly charged photoconductor 30 is irradiated with the pixel laser signal light 8, an electrostatic latent image is formed in accordance with the image signal, and the electrostatic latent image is sequentially visualized by the developing unit 35 to form a toner image. An image is formed. Next, the toner image formed on the photoconductor 30 is
Move to the primary transfer position in contact with the intermediate transfer belt 50,
At the primary transfer position, the images are sequentially transferred onto the intermediate transfer belt 50. The yellow image forming operation ends after the end of the image is transferred to the intermediate transfer belt 50, and the photosensitive member 30
And the intermediate transfer belt 50 stops at the initial position.

During the image formation, the corona charger 34 charges the photosensitive member 30 to -450V, and the exposure potential of the photosensitive member 30 becomes -50V. Further, a DC voltage of −250 V is applied to the developing roller 31. Further, a DC voltage of +1.0 kV is applied to the guide pulley 55C and the tension pulley 55D of the intermediate transfer belt 50.

When the formation of the yellow image is completed and the photosensitive member 30 and the intermediate transfer belt 50 are stopped, the drive source of the apparatus main body 1 engaged with the photosensitive member 30
And the carriage 2 is rotated by 90 ° in the direction of the arrow. Thus, the magenta image forming unit 3M is positioned at the image forming position 10 and stopped at the same time as the yellow image forming unit 3Y moves from the image forming position 10. When the magenta image forming unit 3M stops, the drive source of the apparatus main body 1 engages with the magenta photoconductor 30, the image forming unit 3M and the transfer belt unit 5 start operating, and the same image as in the case of yellow is formed. A forming operation is performed. As a result, yellow and magenta toner images are formed on the intermediate transfer belt 50 in a superimposed manner.

The above operation is repeated in the order of cyan and black, and toner images of four colors are formed on the intermediate transfer belt 50.

The black toner image is transferred to the intermediate transfer belt 50.
After the image is transferred to the secondary transfer roller 9, the secondary transfer roller 9 is brought into contact with the intermediate transfer belt 50 when the head of the image comes to the position of the secondary transfer roller 9, and the recording paper sent from the paper feeding unit 12 is subjected to the secondary transfer. By transporting the toner image between the transfer roller 9 and the intermediate transfer belt 50, the four color toner images are collectively transferred onto the recording paper. At this time, a voltage of +800 V is applied to the secondary transfer roller 9. The recording paper to which the toner image has been transferred passes through the fixing device 15 and is fixed, and is discharged from the discharge roller 18 to the outside of the apparatus.

The toner remaining on the intermediate transfer belt 50 after the secondary transfer is scraped off by the cleaning blade 53 contacting the intermediate transfer belt 50, and the scraped toner is stored in the waste toner case 57 by the screw 52. You.

When the secondary transfer is completed, the intermediate transfer belt 5
0 and the image forming unit 3 stop again, and the carriage 2 rotates by 90 °. Then, the yellow image forming unit 3Y reaches the image forming position 10 again, and is prepared for the next color image forming operation.

(Color Positioning) Next, the details of the positioning of the photosensitive member 30 and the driving mechanism at the image forming position 10 for accurately performing color matching of each color will be described with reference to FIGS.

FIG. 3 is an exploded perspective view showing a carriage and photosensitive member positioning mechanism and a driving mechanism of the color electrophotographic apparatus according to one embodiment of the present invention, and FIG. 4 is a color electrophotographic apparatus according to one embodiment of the present invention. FIG. 3 is a cross-sectional view of the carriage cut along a plane passing an image forming position of the apparatus.

As shown in FIGS. 3 and 4, tapered holes 48 for positioning the image forming unit 3 are provided at both ends of the photosensitive member 30.
A flange 41R, 41L having R, 48L is bonded and fixed, and a photoreceptor bearing 43 in which the outer periphery of the flange 41R, 41L is fixed to the side wall of the photoreceptor unit 37.
R and 43L are attached rotatably. A coupling claw 47 for rotating and driving the photoconductor 30 is provided at the tip of the flange 41R, and the coupling claw 47 can be engaged with a coupling plate 61 on the main body side.

A right side wall 20R and a left side wall 20L are fixed to the center circular tube 21 of the carriage 2. On each of the side walls 20R and 20L, partition ribs 23 are fixedly arranged at four positions so as to divide the inside of the carriage 2 into four parts. Each color image is provided in each space in the carriage 2 partitioned by the partition ribs 23. The forming unit 3 is arranged. Further, the circular tube 21 is provided with exposure windows 97 at a total of four positions through which the pixel laser signal light 8 for photoconductor exposure passes. Note that the carriage 2 is provided on the left and right main body side walls 1
R and 1L are rotatably supported via bearings 46R and 46L.

The carriage gear 2 is provided outside the left side wall 20L.
The carriage gear 28 is integrally formed, and the carriage gear 28 is connected to a carriage drive mechanism 86 provided on the main body side. The carriage drive mechanism 86 includes a worm 89 connected to a drive source (not shown), a worm wheel 88, and the worm wheel 88.
The carriage 2 is freely rotated and positioned by the rotational drive of the carriage drive mechanism 86.

45R, 45L are left and right main body side walls 1R, 1R.
L is a drop prevention guide for preventing the image forming unit 3 provided in the lower half along the outer periphery of the carriage 2 from dropping from the carriage 2.

The second mirror 98 is attached to the main body side walls 1R, 1R near the center of the circular tube 21 by a fixing member (not shown).
L, and is configured to always remain stationary irrespective of the rotation of the carriage 2.

The side walls 20R and 20L are provided with cutouts 26R and 26L at portions where the flanges 41R and 41L of the image forming unit 3 are inserted. This notch 26
The R, 26L and the partition rib 23 serve as a guide when the image forming unit 3 is mounted in the carriage 2. The image forming unit 3 is guided by the fall prevention guides 45R and 45L from the side or below the carriage 2 and does not detach from the carriage 2.

The dimensions of the notches 26R, 26L are set larger than the outer diameters of the flanges 41R, 41L.
When the photoconductor 30 is positioned at the image forming position 10 and is at the reference position, the photoconductor 30 is provided with play in all directions with respect to the carriage 2 at the regular position.
In the present embodiment, this play is ensured at about 1 mm, so that the positioning operation of the photoconductor 30 is not hindered even if the positioning accuracy of the carriage 2 is somewhat poor.

(Photosensitive Member Positioning and Driving Mechanism) In order to accurately position the photosensitive member 30 at the image forming position 10, a photosensitive member driving mechanism 6 is provided on both side walls 1R and 1L of the apparatus main body 1.
0 and a detent mechanism 80 are provided.

The photoconductor driving mechanism 60 is provided on the right main body side wall 1R, and includes an output shaft 70, a coupling plate 61 fixed to the output shaft 70 and rotating integrally with the output shaft 70, and an output shaft driving gear 71. And a drive mechanism for driving these. The output shaft 70 is movably and rotatably supported in a thrust direction by bearings 77 fixed respectively between the right main body side wall 1R and the substrate 67 fixed thereto.

At one end of the output shaft 70, a tip taper portion 75 having a convex tapered surface following the tapered hole 48R of the photosensitive member 30 is formed, and the other end of the output shaft 70 is small in the thrust bearing 69R. It is formed in a spherical shape so that it contacts in area. The output shaft driving gear 71 is a helical gear, and the output shaft driving gear 71 is fixed to the output shaft 70 in a state where the output shaft driving gear 71 meshes with the driving gear 72. Numeral 74 denotes a compression spring inserted between the bearing 77 and the output shaft drive gear 71. The compression spring 74 separates the output shaft 70 and the coupling plate 61 from the flange 41R on the photoconductor 30 side (see FIG. 4 indicates an engaged position).

The output shaft 70 is moved away from the flange 41R by a drive means (not shown) for moving the thrust bearing 69R, and is engaged with the tapered hole 48R shown in FIG. The driving-side gear 72 has a wide tooth width so that the output shaft driving gear 71 is engaged with the driving-side gear 72 at any position. ing. Output shaft 70
When the gears move in the thrust direction, the output shaft driving gear 71 and the driving gear 72 move while sliding on each other's tooth surfaces.

The coupling plate 61 is for transmitting power by engaging with the coupling claw portion 47 of the flange 41R, and has eight coupling claws 65 at its tip.

Next, the detent mechanism 80 provided on the left main body side wall 1L will be described.

The detent mechanism 80 is supported between the main body side wall 1L and the substrate 68 via a bearing 78, and is movable in the thrust direction by a driving mechanism (not shown) for moving the thrust bearing 69L and a compression spring 85. It is constituted by a rotatable detent shaft 81. A tapered surface 84 is formed at one end of the detent shaft 81 so as to follow the tapered hole 48L of the flange 41L.
Is formed in a spherical shape similarly to the output shaft 70, and is pressed against the thrust bearing 69L. Reference numeral 85 denotes a compression spring inserted between the main body side wall 1L and a spring stopper 82 fixed to the detent shaft 81.
This is for always keeping the detent shaft 81 away from the flange 41L.

With the above arrangement, when the image forming unit 3 supported by the carriage 2 is carried to the image forming position and stopped when the output shaft 70 and the detent shaft 81 are separated from the flanges 41R and 41L of the photosensitive member 30, The thrust bearings 69 </ b> R and 69 </ b> L are pushed inward by the drive mechanism, and the tapered end 75 of the output shaft 70 is
The tapered surface 8 of the detent shaft 81 is inserted into the tapered hole 48R of R.
4 are respectively engaged with the tapered holes 48L of the flange 41L, and the photoconductor 30 is accurately positioned at the image forming position 10. When the output shaft driving gear 71 rotates with the output shaft 70 and the detent shaft 81 pressed inward, the coupling claw 65 of the coupling plate 61 is engaged with the coupling claw 47 of the flange 41R. The rotation of the output shaft 70 is transmitted to the photoconductor 30, and the photoconductor 30 is moved to the image forming position 10.
Rotate with. At this time, the output shaft 70 and the detent shaft 81
Since the photoconductor 30, the second mirror 98, and the laser exposure device 6 supported by the camera 2 are all positioned on the apparatus main body 1, the photoconductor 30 can be accurately positioned regardless of the position of the carriage 2. As a result, even if the color is switched, this relationship does not shift, so that no color shift occurs.

Next, the structure of the image forming unit 3 and the driving mechanism of the developing roller in the present embodiment will be described in detail with reference to FIG. 1 and FIGS.

FIG. 5 is a right side view showing an image forming unit according to one embodiment of the present invention, and FIG. 6 is a cross-sectional view showing a swing lever portion provided in a developing unit according to one embodiment of the present invention. 7 is a left side view showing the image forming unit according to the embodiment of the present invention.

First, a method of connecting the photosensitive unit 37 and the developing unit 35 in the image forming unit 3 will be described.

As shown in FIGS. 4, 5, and 7, a projection 91 is provided on the right side wall 37R of the photoreceptor unit 37, and a fulcrum pin 90 is press-fitted and fixed to the projection 91. A guide pin 108 is press-fitted and fixed to the left side wall 37L of the photoconductor unit 37. Further, a guide groove 115 for guiding the developing roller 31 in the direction of the photoconductor 30 is formed on the left side wall 37L of the photoconductor unit 37. The developing unit 35 is disposed inside the side walls 37R and 37L of the photoconductor unit 37,
On the right side wall 37R side, a positioning hole 116 is inserted through a fulcrum pin 90 and is supported rotatably.

As shown in FIG. 4 to FIG.
Are rotatably supported by bearings 105 and 106 fixed to the right side wall 35R and the left side wall 35L of the developing unit 35, respectively. The bearing 106 is fitted in the guide groove 115 on the left side wall 37L side of the photoconductor unit 37,
The left side of the developing unit 35 can move along the guide groove 115 together with the developing unit 35 with respect to the photoconductor unit 37. The guide pin 108 is inserted into the hole 107 provided in the left side wall 35L of the developing unit 35, but the positioning is not performed by this, and both are arranged with a play of about 1 mm. .

The photosensitive unit 37 and the developing unit 35 are combined in the above-described configuration, and the photosensitive unit 37
And the right side wall 35R of the developing unit 35
The fulcrum pin 9 is provided by a compression spring 102 applied between the two.
The developing roller 31 is stopped while being pressed against the photoreceptor 30. Also, a left side wall 37L of the photosensitive unit 37 and a left side wall 35L of the developing unit 35
Are the bearing 106 of the developing roller 31 and the photosensitive unit 3
The developing roller 31 is pulled toward the photoconductor 30 by a tension coil spring 110 that is stretched between the pin 111 and the pin 111 that is set on the left side wall 37 </ b> L of the printer 7, whereby the developing roller 31 is pressed against the photoconductor 30. Stop.

As described above, in the present embodiment,
Developing roller 31 for photoconductor 30 of image forming unit 3
Are performed at three points, that is, the fulcrum pin 90, the right side of the developing roller 31, and the left side of the developing roller 31, so that the photosensitive member 30 and the developing unit 35 are not affected by the dimensional accuracy. The roller 31 can be brought into uniform contact with a constant pressure.

Next, the driving mechanism of the developing roller 31 will be described.

As shown in FIGS. 4 to 6, the developing roller 31
Is a developing drive main body gear 6 attached to the main body side wall 1.
2. It is rotationally driven via a swing gear 94 and a developing roller gear 96 fixed to the developing roller 31. The gear 99 is a gear fixed to the supply roller 33.
Is driven to rotate via a developing roller gear 96 and an idler gear 98.

As shown in FIGS. 5 and 6, the swing gear 94
A pin 93 is attached to a swing lever 92 which is attached to the bearing 105 fixed to the right side wall 35R of the developing unit 35 and the developing roller shaft 97 so as to be swingable about the developing roller shaft 97.
It is rotatably mounted via. Swing lever 9
2, the swinging gear 94 is urged toward the developing drive main body gear 62, and the bottom surface of the swinging lever 92 is moved to the right side wall 37 of the photosensitive unit 37.
It stops by contacting a circular projection 91 around the fulcrum pin 90 of R. Note that the swing lever 92 may directly contact the fulcrum pin 90. As described above, the swing lever 92 is connected to the fulcrum pin 90 or the circular projection 91.
In this case, since the carriage 2 on the main body side supports the image forming unit 3 at a position where the developing unit 35 receives an external force, an unreasonable twisting force is not generated in the image forming unit 3.

When the carriage 2 on which the image forming unit 3 is mounted is driven to rotate, when the tips of the teeth of the developing drive main body gear 62 and the oscillating gear 94 contact each other, the oscillating lever 92 resists the force of the tension spring 104. And the swing gear 94 escapes from the developing drive main body gear 62. When the image forming unit 3 reaches the image forming position 10, the swing gear 94 bites into the developing drive main body gear 62, but the swing lever 92 comes into contact with the circular projection 91 and is stopped. The distance between the center of the developing drive main body gear 62 and the center of the developing drive main body gear 62 are properly secured, and the developing roller 31 rotates in a state of being in contact with the photoconductor 30.

As shown in FIG. 4, the developing drive main body gear 62 is fixed to a developing drive shaft 63 rotatably attached to the right main body side wall 1R and the substrate 67 via a bearing 66, and the developing drive The shaft 63 is rotated from the main body via a developing drive pulley 64 fixed to the developing drive shaft 63.

As described above, the driving force for rotating the developing roller 31 is applied from the outside (body side) of the image forming unit 3, so that the photosensitive member 30 receives the load fluctuation due to the driving of the developing roller 31. In addition, since the contact pressure of the developing roller 31 with respect to the photoconductor 30 can be set small, the photoconductor 30 is hardly subjected to disturbance from the developing roller 31, and stable rotation is ensured.

Next, the principle of driving the photosensitive member 30 and the developing roller 31 stably will be described in detail with reference to FIG.

FIG. 8 is a view for explaining only a main part for driving the photosensitive member 30 and the developing roller 31.

In FIG. 8, reference numeral 96 denotes a developing roller gear;
Reference numeral 4 denotes a swing gear, 62 denotes a developing drive main body gear, and 20R denotes a portion protruding inside the right side wall of the carriage 2. Reference numeral 90 denotes a fulcrum pin for connecting the developing unit 35 and the photoconductor unit 37, and reference numeral 91 denotes a circular projection provided on the right side wall 37R of the photoconductor unit 37. The circular projection 91 and the swing gear 94 are recessed in the notch 29 of the right side wall 20 </ b> R of the carriage 2, and the swing gear 94 is a developing drive main body gear 62.
And are engaged. For this reason, when the image forming unit 3 shakes the head around the photoconductor 30, the circular protrusion 91 contacts the side surface 27 of the notch 29.

In the above-described configuration, when the photosensitive member 30 is coupled to the output shaft 70 and the detent shaft 81 and is positioned at a proper position, and when the developing drive main body gear 62 rotates, the image forming unit 3 is moved from the apparatus main body 1. Both ends of the central axis of the photoconductor 30 are supported. In this state, when the photoconductor 30 and the developing drive main body gear 62 rotate, the image forming unit 3
Receives a counterclockwise rotational moment about the central axis of the supported photoreceptor 30. This rotational moment is stopped by the circular projection 91 abutting on the side surface 27 of the notch 29 of the carriage side wall 20R.
That is, when the image forming unit 3 performs an image forming operation at the image forming position 10, the image forming unit 3 is moved from the apparatus main body 1 to both ends of the central axis of the photoconductor 30 and the circular protrusions on the right side wall 37 </ b> R of the photoconductor unit 37. It is in a state of being supported at three locations 91. For this reason, the positioning of the photoconductor 30 with respect to the apparatus main body 1 can be reliably performed, and the image forming unit 3 is twisted by receiving the developing driving force, so that it is difficult to secure the contact between the photoconductor 30 and the developing roller 31. There is no problem. Further, since the circular protrusion 91 is provided on the right side wall 37R of the photoconductor unit 37, the rotational force of the entire image forming unit 3 is supported only by the photoconductor unit 37, so that the photoconductor 30 and the developing roller The contact state of 31 is not affected.

The swing gear 94 and the developing drive main body gear 6
Reference numeral 2 substantially meshes with a fulcrum pin 90, which is a fulcrum of rotation of the developing unit 35 with respect to the photoconductor unit 37. For this reason, the developing unit 35 is
The force received from 2 is in the direction of the arrow P, which is the pressure angle direction of both gears, but this force does not generate a rotational moment about the fulcrum pin 90 of the developing unit 35 with respect to the photoconductor unit 37. The pressing force between the developing roller 31 and the photoconductor 30 is not generated by the driving force of the roller 31 from the apparatus main body 1.

With the above configuration, the developing roller 3
The pressing force applied to the photosensitive member 30 is the same as the initially set spring force Q (compression spring 1) even during the rotation of the developing roller 31.
02) and the photoreceptor unit 3
7 tension coil spring 110 provided on the left side wall 37L side
Of the photoreceptor 30 and the developing roller 31
Can always be stably contacted with a light force.
Note that even if the direction of the force received by the developing unit 35 from the developing drive main body gear 62 fluctuates slightly due to the fluctuation in the engagement between the swing gear 94 and the developing drive main body gear 62, the pressing force between the developing roller 31 and the photoconductor 30 is reduced. It does not fluctuate. In particular,
In an image forming unit, such as a one-component contact developing method, in which the developing roller and the photoreceptor need to be uniformly contacted over the entire surface with as little force as possible, the structure is simple, and in order to realize high performance at low cost. It is valid.

The rotational moment around the photoconductor 30 received by the image forming unit 3 from the apparatus main body 1 (the rotational moment of the photoconductor 30 and the moment due to the force in the direction of arrow P received from the developing drive main body gear 62) is 37
Is received by the notch 27 of the carriage 2, so that the pressing force of the developing roller 31 against the photoconductor 30 due to the pressing of the developing unit 35 from the carriage 2 does not change. Similarly, since the rotational moment around the photoconductor 30 received from the outside is received at almost the same position (outer circumference of the circular protrusion 91) as the force received from the outside, the reaction force is positioned on the photoconductor 30. Left and right tapered holes 48R, 48L
And the accurate positioning of the photoconductor 30 is not hindered.

In the above embodiment, the driving force of the developing unit 35 is directly received from the apparatus main body 1. However, the driving force is not necessarily limited to this structure. May be received.

[0078]

As described above, according to the present invention,
With a simple configuration, it is hard to apply disturbance to the rotation of the photoconductor, and
Provided is an image forming unit capable of forming a uniform image without unevenness by keeping the contact pressure between a photoreceptor and a developing roller small and uniform, and a high quality color image forming apparatus using the same. Can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an image forming unit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a color electrophotographic apparatus using an image forming unit according to an embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a carriage and a photosensitive member positioning mechanism and a driving mechanism of the color electrophotographic apparatus according to the embodiment of the present invention;

FIG. 4 is a cross-sectional view of the color electrophotographic apparatus according to the embodiment of the present invention, in which a carriage is cut along a plane passing an image forming position.

FIG. 5 is a right side view showing the image forming unit according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a swing lever portion provided in the developing unit according to the embodiment of the present invention.

FIG. 7 is a left side view showing the image forming unit according to the embodiment of the present invention;

FIG. 8 is a drive explanatory diagram of a photosensitive member and a developing roller according to an embodiment of the present invention.

FIG. 9 is a sectional view showing a conventional image forming unit.

[Explanation of symbols]

 2 Carriage 3 Image Forming Unit 5 Transfer Belt Unit 10 Image Forming Position 30 Photoconductor 31 Developing Roller 35 Development Unit 37 Photoconductor Unit 50 Intermediate Transfer Belt 60 Photoconductor Drive Mechanism 62 Development Drive Body Gear 80 Detent Mechanism 90 Support Pin 92 Swing Lever 94 swing gear

Continued on the front page (72) Inventor Shigemitsu Tani 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.F-term (reference) EA14 2H077 AC04 AD06 AD13 BA03 BA07 BA08 BA09 BA10

Claims (10)

[Claims] 1. A photoreceptor unit having a photoreceptor having a surface on which an electrostatic latent image is formed, a developer, a developing roller for carrying the developer in a developing area, and a driving force transmission for rotating the developing roller. And a developing unit for visualizing the electrostatic latent image, wherein the developing unit is swingably supported by the photoconductor unit, and is rotated by the developing unit. An image forming unit, wherein an action point of a force transmitting a force is provided in the vicinity of a swing center axis of the photoconductor unit and the developing unit. 2. The image forming unit according to claim 1, wherein a driving force for rotating the developing roller is applied from outside the image forming unit. 3. The image forming unit according to claim 2, wherein the electrostatic latent image is visualized by bringing the developing roller into contact with the photosensitive member. 4. A photoconductor of the photoconductor unit is supported by the photoconductor unit on the drive side of the development unit so as to be swingable, and a slide guide provided on the photoconductor unit on the opposite side. The image forming unit according to claim 2, wherein a relative position between the image forming unit and the developing roller is determined. 5. A driving gear transmitting means for rotating a developing roller, wherein a driven gear directly driven from outside the image forming unit is supported so as to be able to swing around a rotation axis of the developing roller. The image forming unit according to any one of 2, 3, and 4. 6. An image forming unit further comprising a swinging member for swingably supporting a driven gear, wherein the swinging member is provided in the image forming unit when a rotational force is transmitted to the developing roller from outside the image forming unit. The image forming unit according to claim 5, wherein the image forming unit is locked at an engagement portion. 7. An engagement portion provided at both ends of a rotation shaft of the photoconductor and supported by the apparatus main body, and provided on a driving force transmission side of the developing unit, and performs rotational positioning of the photoconductor around the rotation axis. The image forming unit according to claim 1, further comprising a rotation locking portion. 8. The image forming unit according to claim 7, wherein the rotation locking portion is provided on the photoconductor unit. 9. The fulcrum shaft for supporting the developing unit in a swingable manner or a receiving portion for the fulcrum shaft.
Or the image forming unit according to 8. 10. A plurality of image forming units each including a combination of a developing device and a photoreceptor of a different color, and an image forming unit for sequentially moving and switching the plurality of image forming units between an image forming position and a retreat position. Transfer means, positioning means for positioning the photoconductor at the image forming position, exposure means for exposing the photoconductor located at the image forming position, and the photoreceptor positioned at the image forming position. A transfer unit that forms a color image on which a plurality of color toner images are superimposed on the transfer body by sequentially superimposing the toner images formed by the developing device and transferring the resultant onto a transfer body; and A color electrophotographic apparatus comprising: a transfer unit; and a rotation driving unit that rotationally drives a transfer unit, wherein the image forming unit according to claim 1 is used as the image forming unit. Characteristic color electrophotographic apparatus.