JP2000147948A - Photoreceptor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach a photoreceptor unit to a device main body by effectively restraining irregular density due to jitters, even when using a spur gear. SOLUTION: A photoreceptor drum 7 for a photoreceptor unit 17 is supported rotatably at both ends in the axial direction by a photoreceptor support body 20. A photoreceptor drive gear 21 is provided on one-side end face in the axial direction of the drum 7 and is driven to be rotated from a motor 18 provided on a device main body side through a drive output gear 24, a drive input gear 23 and a photoreceptor coupling gear 22. The modules of the gears 21 and 22 are made small and a cycle in which jitters occur is made short, so that the deterioration in the image quality is restrained to be inconspicuous. The modules of the gear 23 coaxial with the gear 22 and the gear 24 are made large, so as to easily adjust meshing at the time of attaching/detaching the unit 17, whereby the jitter caused by the meshing is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus such as a copying machine or a laser printer, and more particularly to a photoreceptor unit detachably mountable to an electrophotographic apparatus main body.

[0002]

2. Description of the Related Art In an electrophotographic apparatus such as a copying machine, a laser printer, or a plain paper facsimile apparatus, a photosensitive member for optically forming an electrostatic latent image is unitized and detachably attached to the apparatus body. In addition, convenience for maintenance and the like is achieved. For example, Japanese Patent Publication No. 4-4839
0, JP-A-3-245160 and JP-A-10-397
15 and the like disclose a prior art relating to a process cartridge having a photoconductor and a function of performing at least one of charging, development, and cleaning.

FIG. 7 schematically shows a structure for rotating a photosensitive drum 101 with a conventional basic photosensitive unit 100. In the photoconductor unit 100, the photoconductor drum 101 is connected to the photoconductor support 10 at one end in the axial direction.
2 rotatably supported. Photoconductor drum 1
01 is similarly supported at the other end in the axial direction. A photoconductor driving gear 103 for rotating and driving the photoconductor drum 101 is provided on one axial end surface of the photoconductor drum 101.
Are disposed coaxially with the photosensitive drum 101. With such a configuration, the photoconductor driving gear 10
When the rotational driving force is transmitted to the photosensitive drum 3, the photosensitive drum 101 rotates.

A rotational driving force is transmitted to the photoconductor drive gear 103 via a motor-side gear 104 that meshes when the photoconductor unit 100 is mounted on the main body of the electrophotographic apparatus. To the motor-side gear 104, a rotational driving force from a motor 105, which is a driving source provided in the main body of the electrophotographic apparatus, is transmitted at a reduced speed. Spur gears are frequently used for the photoconductor driving gear 103 and the motor-side gear 104.

[0005] On the other hand, the normal motor 105 has uneven rotation. One of the causes of the uneven rotation is uneven speed called "jitter" in the rotation of the photosensitive drum 101. Such jitter is also caused by unevenness in the accuracy of engagement between the motor-side gear 104 and the photoconductor driving gear 103, and delicate vibration due to contact between teeth during the engagement. The uneven speed thus generated causes uneven charging, uneven development, or uneven transfer of the photosensitive drum 101, and generates periodic density unevenness in the resulting image according to the uneven speed. . Such density unevenness is particularly noticeable when a halftone image is formed.

In order to improve the density unevenness, the motor 105
If the reduction ratio from when the driving force is transmitted to the photosensitive drum 101 is increased, the effect can be reduced to some extent. However, density unevenness due to the engagement accuracy between the motor-side gear 104 and the photoconductor drive gear 103 and minute vibration due to contact between teeth during engagement can be solved even if the reduction ratio is increased. Can not. The occurrence of minute vibration due to the contact between the teeth during the meshing is likely to occur when the photosensitive member driving gear 103 and the motor side gear 104 are spur gears. The meshing accuracy can be improved by using a large gear for a module which is a value obtained by dividing the gear diameter as the diameter of the pitch circle of the gear by the number of teeth. However, the fine movement due to the contact between the teeth appears in a large cycle, the pitch of the jitter becomes coarse, and the above-mentioned density unevenness is easily observed visually.

FIG. 8 shows a schematic configuration of the prior art disclosed in the above-mentioned Japanese Patent Publication No. 4-48390. In this prior art process cartridge 110, the photosensitive drum driving gear 1 is pressed so that the photosensitive drum 111 is pressed against the cartridge housing corresponding to the photosensitive member support 112.
A helical gear is used for a drum gear and a drum drive gear corresponding to 13 and the motor-side gear 114. In this prior art, an object is to use a helical gear to generate an axial thrust force, improve the axial displacement of the photosensitive drum 111, and obtain good image quality. Since the helical gear is used, the contact is softer than in the case of the combination of the photosensitive member drive gear 103 and the motor side gear 104 of the spur gear as shown in FIG. Fine movement occurring during alignment may also be reduced, and density unevenness due to jitter may be effectively suppressed.

In the prior art of JP-A-3-245160,
There is disclosed a configuration in which gears are provided at side end portions of the photoconductors 3 and 3 ′, and the photoconductors 3 and 3 ′ are rotationally driven in mesh with a drive transmission gear on the apparatus main body side. The gear used in this prior art is a spur gear, and there should be a similar problem with respect to jitter as in FIG. Japanese Patent Application Laid-Open No. H10-39715 discloses a prior art in which a gear having a diameter twice or more the diameter of the photosensitive drum is provided at one end of the photosensitive drum, and the gear is driven to rotate from the apparatus main body side. Also in this prior art, since the rotation of the photosensitive drum is equivalent to that in FIG. 7, the same problem of jitter occurs.

[0009]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 4-48390
In the configuration of the prior art disclosed in the publication, a helical gear whose teeth mesh obliquely is used, so that a load for driving transmission is increased as compared with a spur gear. For this reason, the load on the motor 115 used as a drive source increases, and a large-sized and large-torque motor 115 is required. Therefore, there is a problem that it is not compatible with the compactness and energy saving which are recently required for the electrophotographic apparatus.

In the prior art disclosed in Japanese Patent Application Laid-Open No. H10-39715, the module of the last-stage gear joined to the shaft of the photosensitive drum via a joint can be used as a minimum practical limit. In this prior art, the last-stage gear is installed on the main body side and is joined to the shaft of the photosensitive drum using a joint.
For this reason, the number of parts, such as the parts that make up the joint, increases,
In addition, the use of a large gear makes it difficult to downsize the device.

[0011] JP-B-4-48390 and JP-A-3-245
When the small module gear is mounted on the side end of the photosensitive drum of the photoconductor unit in the prior art of 160, the meshing between the small gears of the module is adjusted between the main body of the electrophotographic apparatus and the photoconductor unit. There is a need. It is very difficult to combine the small gears of the module in an appropriate meshing state because the gears of the small module have small teeth and a small difference between the pitch circle and the addendum circle.

An object of the present invention is to use a spur gear, eliminate the need for using a large-sized and large-torque motor, effectively suppress density unevenness due to jitter, and obtain a high-quality image. In addition, it is an object of the present invention to provide a photoreceptor unit capable of easily mounting the photoreceptor unit on an apparatus main body.

[0013]

According to the present invention, there is provided a photoreceptor unit having a drum-shaped photoreceptor and a photoreceptor support for rotatably supporting the photoreceptor, and being detachably mountable to an electrophotographic apparatus main body. , A photoconductor driving gear provided coaxially with the photoconductor on an axial side end surface of the photoconductor, and a drive output of the electrophotographic apparatus main body when the photoconductor unit is mounted on the electrophotographic apparatus main body. A drive input gear larger than the photoreceptor drive gear module, the module being disposed between the drive input gear and the photoreceptor drive gear, wherein the module is different from the drive input gear to the photoreceptor drive gear And a driving force transmitting mechanism for transmitting driving force between modules.

According to the present invention, the photoreceptor unit has a drum-shaped photoreceptor and a photoreceptor support that freely supports the photoreceptor, and is detachable from the electrophotographic apparatus main body. A photoreceptor drive gear is provided coaxially with the photoreceptor on the axial side end surface of the photoreceptor. The photoreceptor unit is further provided with a drive input gear that meshes with a drive output gear on the electrophotographic apparatus main body side when the photoreceptor unit is mounted on the electrophotographic apparatus main body. The drive input gear module is larger than the photoreceptor drive gear module. A driving force transmission mechanism that transmits driving force between different modules is provided between the driving input gear and the photoconductor driving gear. When the photoconductor unit is mounted on the main body of the electrophotographic apparatus, the driving input gear receives rotational driving force from the drive output gear of the main body of the electrophotographic apparatus, and the photoconductor in the photoconductor unit has a smaller module than the drive input gear. Rotational driving force is transmitted to the drive gear via a drive transmission mechanism. The rotational driving force transmitted to the photoconductor driving gear rotationally drives the photoconductor coaxial with the photoconductor driving gear. Since the size of the drive input gear module is increased, it is possible to accurately adjust the drive input gear and the drive output gear when the photoreceptor unit is mounted on the main body of the electrophotographic apparatus. Since the photoreceptor drive gear has a small module, the fine movement due to teeth and tooth contact in the photoreceptor drive gear, which is directly related to the rotational speed unevenness of the photoreceptor, is set to a fine pitch that is not observed visually. Therefore, the influence of uneven density due to jitter can be made inconspicuous. Even if a spur gear is used for each gear, the jitter becomes inconspicuous, so that a high-quality image can be obtained without using a large and large torque motor.

In the driving force transmission mechanism according to the present invention, the photoconductor-side connection gear connected to the photoconductor drive gear and the drive input gear or the drive-side connection gear connected to the drive input gear are coaxial. It is characterized by comprising a coaxial two-stage gear disposed above and rotating integrally.

According to the present invention, since the driving force transmission mechanism is constituted by a coaxial two-stage gear which is arranged coaxially and rotates integrally, the transmission of the rotational driving force between the gears of different modules. Can be performed reliably.

In the present invention, the photoconductor-side connection gear and the drive input gear or the drive-side connection gear constituting the drive force transmission mechanism are more driven than the photoconductor-side connection gear by the drive input gear or the drive-side connection gear. It is characterized in that the gear diameter is larger.

According to the present invention, the drive input gear or the drive-side connecting gear and the photoconductor-side connecting gear which are arranged coaxially and rotate integrally have the gear diameter of the drive input gear or the drive-side connecting gear. Since it is large, the peripheral speed becomes large, and even if the module is large, the period of the speed unevenness becomes small, so that the influence of the jitter can be dispersed and made inconspicuous.

In the present invention, the photosensitive member driving gear and the photosensitive member side connecting gear connected thereto are positioned by an integrated positioning member.

According to the present invention, the photoconductor drive gear and the photoconductor-side connection gear connected to the photoconductor drive gear are integrally positioned by the positioning member. Is maintained in a high state, and a phenomenon called “tooth skip” or “tooth bottom contact” of the photoconductor drive gear does not occur, so that the drive load can be reduced.

Further, the present invention is characterized in that another photosensitive member side connecting gear is interposed between the photosensitive member driving gear and the photosensitive member side connecting gear constituting the driving force transmitting mechanism.

According to the present invention, since the driving force transmission mechanism is constituted by interposing a number of gears, torque fluctuations such as uneven rotation of the driving source can be reduced while the rotation driving force is transmitted to the photosensitive member. , It is possible to reduce the rotation unevenness on the photoconductor side,
Density unevenness due to jitter can be made inconspicuous.

[0023]

FIG. 1 shows a schematic configuration of a laser printer 1 which is an electrophotographic apparatus on which a photoreceptor unit is mounted according to an embodiment of the present invention. In the laser printer 1, the transfer paper P fed from the manual feed tray 2 to the paper feed roller 3 passes through the image forming unit 4 and is discharged to the paper discharge unit 6 by the paper discharge roller 5. The image forming unit 4 includes a photosensitive drum 7
The developing device 8 is provided around the photosensitive drum 7.
A transfer charger 9, a cleaning device 10, and a main charger 11 are provided. In the upper part of the developing device 8,
A writing optical system 12 is provided, and scans the surface of the photosensitive drum 7 with a laser beam. The laser beam is used to determine the presence or absence of irradiation in synchronism with the scanning and the intensity of irradiation.
Draw an image on the surface of. An optical semiconductor layer is provided on the surface of the photosensitive drum 7, and when exposed to laser light, an electrostatic latent image corresponding to an image is formed on the surface of the photosensitive drum 7. The developing device 8 performs development that causes toner to be attracted to the electrostatic latent image formed on the surface of the photoconductor drum 7 and converts the electrostatic latent image into a visible image. The transfer charger 9 transfers a visible image formed of toner on the surface of the photosensitive drum 7 to the surface of the transfer paper P conveyed between the transfer charger 9 and the photosensitive drum 7. The cleaning device 10 removes toner remaining on the surface of the photosensitive drum 7. Fixing unit 13
Is provided for fixing the toner image transferred onto the transfer paper P from the surface of the photosensitive drum 7 by the transfer charger 9 by heat. The transfer paper P can be supplied from a paper feed cassette 14 provided at the bottom of the laser printer 1.

In the electrophotographic apparatus such as the laser printer 1, the photosensitive member is used to supply toner to the developing device 8 and to remove the transfer paper P which has been jammed due to entanglement during conveyance. The photoconductor unit including the drum 7 is configured to be detachable. When the photoconductor unit is attached / detached, the photoconductor drum 7 is attached / detached to / from the main body of the laser printer 1 together with the photoconductor unit. Photoconductor drum 7
Is driven inside the main body of the laser printer 1, so that when the photoconductor unit is mounted on the main body of the laser printer 1, the photoconductor drum 7 is rotated by the driving force from the driving source. When the photoconductor unit is detached from the main body of the laser printer 1, the photoconductor drum 7 is separated from the driving source.

FIG. 2 shows the photosensitive unit 17 of this embodiment.
The configuration for rotationally driving the photosensitive drum 7 will be described.
A motor 18 and a driving force transmission mechanism 19 are provided on the main body side of the laser printer 1 from which the photoconductor unit 17 is detachable. The photoconductor drum 7 is rotatably attached to the photoconductor support 20 at both ends in the axial direction. A photoconductor drive gear 21 is coaxially mounted on one axial end surface of the photoconductor drum 7. When the rotation driving force is transmitted to the photoconductor drive gear 21, the photoconductor drum 7 also rotates with the rotation of the photoconductor drive gear 21.

In the photoconductor unit 17, a photoconductor coupling gear 22 and a drive input gear 23 that mesh with the photoconductor drive gear 21 are also provided. When the photoconductor unit 17 is mounted on the apparatus main body of the laser printer 1, the drive input gear 23 is driven by a drive output via a driving force transmission mechanism 19 from a motor 18 provided as a driving source on the apparatus main body side. The gear meshes with the gear 24. The photoconductor coupling gear 22 and the drive input gear 23 are mounted on the same shaft rotatably mounted by the photoconductor support 20, and rotate integrally.

The drive input gear 23 includes a photosensitive member connecting gear 22
It is formed so that the gear diameter is larger than that. As a result, although the angular velocity of the photoconductor coupling gear 22 and the drive input gear 23 provided on the same axis are the same, the peripheral velocity is proportional to the gear diameter, so that the peripheral velocity of the photoconductor coupling gear 22 is lower. , The peripheral speed of the drive input gear 23 is higher.

In this embodiment, the photoconductor drive gear 21 and the photoconductor connection gear 22 and the drive input gear 23 and the drive output gear 24 have the same module. However, the modules of the photoconductor-side gear system such as the photoconductor drive gear 21 and the photoconductor coupling gear 26 are smaller than the modules of the motor-side gear system such as the drive input gear 23 and the drive output gear 24. The module is a value obtained by dividing the diameter of the pitch circle of the gear by the number of teeth formed on the outer circumference, and represents the size of the teeth. Therefore, a gear system with a smaller module has finer teeth, and a gear system with a larger module has coarser teeth. In the present embodiment, by reducing the size of the photoreceptor-side gear system module and increasing the size of the motor-side gear system module, density unevenness due to jitter can be effectively suppressed.

In the case of the engagement of a tooth having a large module,
The range in which the rotational driving force can be transmitted more smoothly than when the module is small can be widened. In the case of meshing of gears having small modules, the state of "tooth skipping" where the meshing state is insufficient and the state of "tooth root contact" where meshing is excessive are likely to occur. In the present embodiment, since the size of the motor-side gear system module is increased, it is easy to appropriately adjust the engagement between the drive input gear 23 and the drive output gear 24 when the photoconductor unit 17 is mounted, The condition for positioning the photoconductor unit 17 and the main body of the electrophotographic apparatus can be relaxed. If the engagement of the gear system on the motor side is improved, it is possible to suppress the occurrence of jitter due to the alignment when the photoconductor unit is attached.

Further, since the photosensitive member connecting gear 22 and the drive input gear 23 are configured as two-stage gears provided coaxially, they can be rotated at the same angular velocity even if the module is changed. Accordingly, the drive input gear 23 is a large module that can easily improve the accuracy when the photoconductor unit 17 is mounted, but the photoconductor-side gear system module that rotationally drives the photoconductor drum 7 is made smaller. The effect of jitter can be made inconspicuous. That is, when the rotational driving force is transmitted to the photoconductor driving gear 21 for rotating the photoconductor drum 7 by the photoconductor coupling gear 22, the fine movement caused by the contact between the teeth cannot be visually observed. The pitch can be fine, and the effect of jitter can be made inconspicuous.

FIG. 3 shows an outline of the jitter generated in the photosensitive member connecting gear 22 and the drive input gear 23 which are two-stage gears provided coaxially. FIG. 3A shows the relationship of the jitter when the module ratio between the photosensitive member connecting gear 22 and the drive input gear 23 is 1: 1 and the peripheral speed ratio is also 1: 1. In this case, the rotation unevenness period of one tooth of the photoreceptor-side gear system and the rotation unevenness period of one tooth of the motor-side gear system are both large, so that the density unevenness becomes conspicuous.

FIG. 3B shows the relationship of the jitter when the photoreceptor-side gear system module is の of the motor-side gear system module and the peripheral speed ratio is 1: 1. In the photoreceptor-side gear system, the size of the module is small, so that the influence is finely dispersed and can be made inconspicuous so that it cannot be detected visually. The smaller the module, the more finely the jitter can be dispersed. However, the density unevenness caused by the rotation unevenness period of one tooth of the drive-side gear system becomes conspicuous.

FIG. 3C shows that the module of the drive side gear system is made smaller than that of the motor side gear system, for example, 1/2, and conversely, the peripheral speed ratio is 1: 2, and Is to be larger. The photoconductor coupling gear 22 has a small peripheral speed though its module is small. Drive input gear 23
Has a large module but a high peripheral speed. For this reason, both jitters appear at the same period, are dispersed small as a whole, and are less noticeable. Although it is difficult to reduce the size of the drive input gear 23 in terms of easy adjustment of the engagement when the photoconductor unit is attached and detached, the peripheral diameter of the drive input gear 23 is made larger than that of the photoconductor connection gear 22 by increasing the gear diameter. And the pitch of the jitter can be reduced.

FIG. 4 shows a partial configuration of a photoconductor unit according to a second embodiment of the present invention. In the present embodiment, portions corresponding to the portions described above are denoted by the same reference numerals, and redundant description will be omitted. In the photoconductor unit 25 of the present embodiment, a new photoconductor coupling gear 26 is disposed between the photoconductor drive gear 21 and the photoconductor coupling gear 22, and the drive input gear 23 and the drive output gear 24 In between,
A new drive side connection gear 27 is provided. That is,
The photoconductor unit shown in FIG.
2 and the drive-side connecting gear 27, the influence of torque fluctuations such as uneven rotation of the motor 18 on the photosensitive drum 7 can be made smaller than that of the photosensitive unit 17 in FIG. The photoconductor-side connection gear 26 is disposed between the photoconductor drive gear 21 and the photoconductor connection gear 22, and the drive-side connection gear 27 is disposed between the drive input gear 23 and the drive output gear 24. Even if the output gear 24 has uneven rotation due to vibration or the like caused by rotation of the motor 18, the effect can be reduced. As a result, density unevenness due to jitter can be suppressed to be less noticeable.

In the present embodiment, the photosensitive member connecting gear 26 and the driving side connecting gear 27 which are newly added are supported at both ends in the axial direction by the photosensitive member supporting members 28, respectively.
The photoconductor drive gear 21, the photoconductor connection gear 22, and the photoconductor connection gear 26 are the same module, and include a drive input gear 23, a drive output gear 24, and a drive side connection gear 2
7 is also the same module. However, the module of the photoconductor-side gear system such as the photoconductor drive gear 21 is smaller than the module of the drive-side gear system such as the drive input gear 23 as in FIG.

FIG. 5 shows a partial configuration of a photoconductor unit 29 according to a third embodiment of the present invention. In the present embodiment, a positioning member 30 is further provided in the configuration of the second embodiment shown in FIG. 4 to position the photoconductor drive gear 21 and the photoconductor coupling gear 26 integrally. In the photoreceptor-side gear system, the size of the module is small, so that the meshing needs to be adjusted with high accuracy. In the present embodiment, when assembling the photosensitive drum 7 in the photosensitive unit 29, the photosensitive member drive gear 22 and the photosensitive member coupling gear 26 are integrally aligned using the positioning member 30. When the module is made finer, it becomes difficult to increase the accuracy of the engagement. However, only by mounting the positioning member 30 for performing such an integral alignment to the photosensitive member support 28, the photosensitive member The accuracy of the engagement between the drive gear 21 and the photoconductor coupling gear 26 can be easily improved. When the positioning accuracy of gear engagement is poor,
Although the phenomenon called “tooth jump” or “tooth bottom contact” of the photoconductor drive gear 21 is likely to occur, the positioning member 3
By using 0, the accuracy can be improved and such a phenomenon can be eliminated. Further, if the meshing state of the gears is properly set, the optimal loss at the time of transmission also occurs, so that the driving load can be reduced.

FIG. 6 shows a partial configuration of a photoconductor unit 31 according to a fourth embodiment of the present invention. In this embodiment, both ends in the axial direction of the photosensitive drum 7 are rotatably supported by the photosensitive member support 32. A photoconductor drive gear 21 is provided on one end surface of the photoconductor 7 in the axial direction, and meshes with a photoconductor coupling gear 26. The photoconductor coupling gear 26 meshes with the photoconductor coupling gear 33, and a drive input gear 34 provided coaxially with the photoconductor coupling gear 33 meshes with the drive output gear 24 of the main body of the laser printer 1 for transmission. Is rotated by the rotation driving force. In this embodiment, the photoreceptor-side gear system module composed of the photoreceptor drive gear 21, the photoreceptor connection gear 26, and the photoreceptor connection gear 33 is reduced in size, and the module of the combination of the drive input gear 34 and the drive output gear 24 is reduced. At the same time, the gear diameter of the photoconductor coupling gear 33 configured as a coaxial double gear is made larger than the gear diameter of the drive input gear 34. In this embodiment, the photoreceptor-side gear system has a smaller module,
Moreover, since the peripheral speed increases, the period of the jitter in the drive-side gear system becomes larger, and the period of the jitter in the photoconductor-side gear system becomes smaller. The present embodiment may be able to reduce the overall jitter in relation to the cycle of vibration of the motor 18 and the like.

In each of the embodiments described above, it is assumed that the photoconductor unit is attached to and detached from the laser printer 1. However, as an electrophotographic apparatus, an image is formed using an electrophotographic process such as a copying machine or a facsimile machine. The present invention can be similarly applied to a photoreceptor unit of an apparatus for forming a photoreceptor.

[0039]

As described above, according to the present invention, the module for the drive input gear and the module for the photoconductor drive gear are separately designed, so that the module for the photoconductor drive gear is small and the module for the drive input gear is large. can do. When the photoconductor unit is attached to the main body of the electrophotographic apparatus, the accuracy of the engagement between the drive input gear and the drive output gear, which may cause jitter if the engagement accuracy is not adjusted well, can be easily adjusted because the module is large. it can. As a result, the accuracy required for positioning the photoconductor unit and the main body of the electrophotographic apparatus can be reduced. In addition, since the photoreceptor drive gear has a small module, the fine movement caused by the contact between the teeth is reduced, and the rotational speed unevenness of the photoreceptor is reduced. Can be variable. Therefore, density unevenness due to jitter can be reduced and made less noticeable. Even if a spur gear is used as each gear, the density unevenness can be reduced, so that the torque of the motor can be reduced to reduce the size.

Further, according to the present invention, the photoconductor connecting gear and the drive input gear or the drive side connecting gear are different in the module provided on the same axis regardless of whether they are integrally formed or connected and driven together. Driving force can be reliably transmitted between the gears.

Further, according to the present invention, since the peripheral speed on the driving side is increased, the pitch of the jitter can be reduced to make it less noticeable.

Further, according to the present invention, since the photoreceptor drive gear module is small, it can be integrated with the positioning member in advance to ensure the accuracy of engagement with the photoreceptor-side connecting gear. The phenomenon called "tooth jump" and "tooth root contact" of the photoconductor drive gear is less likely to occur,
The driving load can also be reduced.

Further, according to the present invention, while the rotational driving force is transmitted between the plurality of gears of the driving force transmitting mechanism, torque fluctuations such as rotational unevenness of the driving source and load fluctuations are reduced, and the photosensitive member side Can be reduced, and density unevenness due to jitter can be made inconspicuous.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a schematic configuration of a laser printer device 1 including a photoreceptor unit according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a photoconductor unit 17 of the embodiment of FIG.

FIG. 3 is a waveform diagram showing a relationship between a drive input gear 23 and a photoconductor coupling gear 22, a module ratio, a peripheral speed ratio, and jitter in the embodiment of FIG.

FIG. 4 shows a photoconductor unit 25 according to a second embodiment of the present invention.
FIG.

FIG. 5 illustrates a photoconductor unit 29 according to a third embodiment of the invention.
FIG.

FIG. 6 illustrates a photoconductor unit 31 according to a sixth embodiment of the invention.
FIG.

FIG. 7 is a partial cross-sectional view of a conventional photoconductor unit 100.

FIG. 8 is a partial cross-sectional view of a photoconductor unit according to the prior art.

[Description of Signs] 1 Laser printer 7 Photoconductor drum 17, 25, 29, 31 Photoconductor unit 20, 28, 32 Photoconductor support 21 Photoconductor drive gear 22, 33 Photoconductor coupling gear 23, 34 Drive input gear 24 Drive output gear 26 Photoconductor-side connection gear 27 Drive-side connection gear 30 Positioning member

Claims (5)

[Claims] 1. A photoreceptor unit having a drum-shaped photoreceptor and a photoreceptor support rotatably supporting the photoreceptor, the photoreceptor unit being detachable from an electrophotographic apparatus main body. A photoreceptor drive gear provided coaxially with the photoreceptor on the side end surface, and a photoreceptor unit meshes with a drive output gear on the electrophotographic apparatus main body side when the photoreceptor unit is mounted on the electrophotographic apparatus main body, so that the module becomes A drive input gear larger than the photoreceptor drive gear module; and a drive input gear disposed between the drive input gear and the photoreceptor drive gear, for transmitting a driving force between different modules from the drive input gear to the photoreceptor drive gear. A photoreceptor unit comprising a driving force transmission mechanism. 2. The driving force transmission mechanism according to claim 1, wherein the photoconductor-side connection gear connected to the photoconductor drive gear and the drive input gear or the drive-side connection gear connected to the drive input gear are coaxial. 2. The photoconductor unit according to claim 1, comprising a coaxial two-stage gear disposed and integrally rotated. 3. A photoconductor-side connection gear and the drive input gear or the drive-side connection gear that constitute the driving force transmission mechanism, wherein the drive input gear or the drive-side connection gear is greater than the photoconductor-side connection gear. 3. The photoconductor unit according to claim 2, wherein the gear diameter is large. 4. The photoconductor drive gear and a photoconductor-side connection gear connected thereto are positioned by an integrated positioning member.
2. The photoconductor unit according to item 1. 5. A photoconductor-side connection gear is interposed between the photoconductor drive gear and a photoconductor-side connection gear constituting the driving force transmission mechanism. The photoconductor unit according to any one of the above.