JPH09197905A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform excellent image formation by increasing the transmission efficiency and meshing rate and making the rotation of a photosensitive drum smooth. SOLUTION: A stepped gear 33 for driving reception is fixed to one end of the photosensitive drum 13 and when a process unit is mounted on an image forming device main body 11, the stepped gear 33 for driving reception engages a drum driving stepped gear 40 of the image forming device main body. The stepped gear 33 for driving reception and stepped gear 40 for drum driving are constituted by bringing two spur gears of the same module into contact with each other so that their teeth are 1/2-pitch out of phase, and slanting parts are formed at the peak parts of teeth on the side where one gear and the other gear face each other so that the peak part of one gear and the peak part of the other gear form a V shape.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrostatic latent image carrier,
A process unit integrally incorporating a charging device for charging the surface of the electrostatic latent image holding member and a developing device for developing the electrostatic latent image formed on the surface of the electrostatic latent image holding member with toner to visualize it. The present invention relates to an image forming apparatus detachably provided in an image forming apparatus main body.

[0002]

2. Description of the Related Art For example, in an image forming apparatus using a photosensitive drum as an electrostatic latent image holder, the surface of the photosensitive drum is uniformly charged by a charger, and then the surface of the photosensitive drum is exposed by an exposing device. Image information is recorded as an electrostatic latent image on the recording medium, the electrostatic latent image is developed with toner from a developing device to be visualized as a toner image, and the toner image is transferred onto a transfer sheet by a transfer device. Then, the transfer paper on which the toner image has been transferred is thermally fixed by a thermal fixing device and then discharged to the outside. Further, after the transfer, the photosensitive drum is destaticized by a destaticizing lamp, the residual toner remaining on the photosensitive drum is removed by a cleaning device, and the photosensitive drum is put on standby for the next charging.

In such an image forming apparatus, for example, a photosensitive drum, a charging device, a developing device, a discharging lamp, and a cleaning device are integrated as a process unit, and the process unit is detachably attached to the main body of the image forming device. It has been known. The positioning of the process unit with respect to the image forming apparatus main body is performed by a positioning member that attaches the housing of the process unit to the image forming apparatus main body. However, the photosensitive drum needs to rotate smoothly, and a slight gap is provided between the casing of the process unit and the photosensitive drum. For this reason, when the photosensitive drum is rotationally driven from the drive source provided in the main body of the image forming apparatus via the driving force transmission mechanism, the position of the photosensitive drum changes, and a problem that a good quality image cannot be formed occurs.

In view of this, in Japanese Patent Publication No. 4-48390, a process unit housing is provided with an abutting reference surface of a photosensitive drum, and a helical gear is used as a drive gear of the photosensitive drum. There is disclosed a configuration in which the photosensitive drum together with the process unit housing is biased to the regular position of the image forming apparatus main body by the thrust force generated when it is driven from. That is, as shown in FIG.
A flange 2 and a drum gear 3, which is a helical gear, are fixed to one end of the photosensitive drum 1, and the drum gear 3 meshes with a drive gear of a developing roller to drive it.
Further, the drum positioning pin 5 is fitted into the center hole of the flange 2 from the process unit housing 4, and the drum gear 3
Fits in the hole of the process unit housing 4 to rotatably support the photosensitive drum 1 in the housing 4. Further, the positioning pin 7 is fitted to the process unit housing 4 from the copying machine body 6, and the pin 8 is fitted to the center hole of the drum gear 3 to support the process unit housing 4 in the copying machine body 6. doing.

The main body 6 of the copying machine is provided with a drum drive gear 9 composed of a helical gear, and the drum drive gear 9 is rotationally driven by the motor of the main body to drive the drum gear 3 from the drum drive gear 3. To give. In this configuration, if the drum gear 3 is a helical gear to the left in the torsion direction, when the drum gear 3 is driven, a thrust force is generated in the left direction of the photosensitive drum 1 in the figure, and the photosensitive drum 1 is driven.
Is urged to the left in the figure. The entire process unit housing 4 is also urged to the left and pressed against the copying machine body 6. Thus, the process unit is accurately positioned with respect to the copying machine main body 6 in the axial direction about the photosensitive drum 1.

[0006]

However, in the case of using the helical gear as described above, the driving force is dispersed by the thrust force in the direction of the rotating shaft generated by the torsion angle of the helical gear, and the spur gear is used. There is a problem that the transmission efficiency of the driving force is poor as compared with the case of performing. Further, due to the sliding surface resistance of the abutting reference surface portion, there is a problem that rotation is not performed smoothly and image jitter failure occurs.

Although it is possible to use spur gears instead of helical gears, when the spur gears are used, for example, assuming that the number of teeth is about 120, the meshing ratio when the pressure angle is 20 °. Becomes about 1.8, and 2.0 or more cannot be obtained. A meshing ratio of less than 2.0 means that two pairs of teeth are meshed between the 0.8x normal pitch at the beginning and the end of gear meshing, but 1.0x normal line at the center. Only one pair of teeth will engage during the pitch. Since the photosensitive drum has members such as a developing device and a cleaning device that have a large load resistance for rotation of the drum,
For example, if you use plastic gears as gears,
In particular, the amount of deflection of the gear is different between when the full load of driving force transmission to the photosensitive drum is handled by one pair of teeth and when it is handled by two pairs of teeth. There was a problem that caused poor jitter.

Therefore, the invention according to claim 1 is an image forming apparatus in which a process unit integrally incorporating an electrostatic latent image holder, a charger, a developing device, etc. is detachably provided in the image forming apparatus main body. By using a stepped gear as the drive receiving gear of the electrostatic latent image holding member and the image forming apparatus main body side driving gear, the transmission efficiency of the driving force can be improved and the meshing ratio can be increased. The rotation of the electro-latent image carrier is smooth and good image formation can be performed, and moreover, when the process unit is mounted on the main body of the image forming apparatus, the drive receiving step gear and the drive step gear can be accurately meshed with each other. An image forming apparatus is provided.

According to a second aspect of the present invention, there is provided an image forming apparatus in which a process unit in which an electrostatic latent image holding member, a charger, a developing device and the like are integrally incorporated is detachably provided in an image forming apparatus main body. By using a stepped gear as the drive receiving gear of the electrostatic latent image holding member and the image forming apparatus main body side driving gear, the transmission efficiency of the driving force can be improved and the meshing ratio can be increased. (EN) An image forming apparatus capable of always accurately positioning the electrostatic latent image holder with respect to the main body of the forming apparatus, thereby further smoothing the rotation of the electrostatic latent image holder and forming a better image.

According to a third aspect of the present invention, there is provided an image forming apparatus in which a process unit in which an electrostatic latent image holder, a charger, a developing device and the like are integrally incorporated is detachably provided in an image forming apparatus main body. By using a stepped gear as the drive receiving gear of the electrostatic latent image holding member and the image forming apparatus main body side driving gear, the transmission efficiency of the driving force can be improved and the meshing ratio can be increased. Positioning of the electrostatic latent image holder with respect to the main body of the image forming apparatus can always be performed accurately, which allows the electrostatic latent image holder to rotate more smoothly to form a better image. (EN) Provided is an image forming apparatus capable of accurately meshing a drive receiving step gear and a drive step gear when being mounted on.

[0011]

According to the first aspect of the present invention,
An electrostatic latent image carrier, a charging device for charging the surface of the electrostatic latent image carrier, and a developing device for developing the electrostatic latent image formed on the surface of the electrostatic latent image carrier with toner to visualize it. In the image forming apparatus in which the built-in process unit is detachably provided in the image forming apparatus main body, a stepped gear consisting of two gears is used as a drive receiving gear of the electrostatic latent image holding member, When the process unit is mounted, a drive step gear consisting of two gears that mesh with the drive step gear of the electrostatic latent image carrier is provided, and the drive step gear and the drive step gear are respectively two sheets. By shifting the phase of the teeth of the gear to make a close contact,
An inclined portion is formed in the mountain portion of the teeth on the side where one gear and the other gear face each other so that the mountain portion of one gear and the mountain portion of the other gear form a V shape. . As a result, when the drive receiving step gear and the drive step gear mesh with each other, even if there is some deviation, the amount of deviation is corrected by the inclined portions of the teeth of both the step gears, and the gears are accurately meshed.

The invention according to claim 2 is an electrostatic latent image carrier,
Image a process unit that incorporates a charger that charges the surface of the electrostatic latent image carrier and a developer that develops the electrostatic latent image formed on the surface of the electrostatic latent image carrier with toner to make it visible. In the image forming apparatus detachably provided in the forming apparatus main body,
A step gear consisting of two gears is used as a drive receiving gear of the electrostatic latent image holding member, and meshes with the drive receiving step gear of the electrostatic latent image holding member when the process unit is attached to the image forming apparatus main body. A drive stage gear consisting of two gears is provided, and the drive receiving stage gear and the drive stage gear are closely contacted by shifting the phases of the tips of the two gears, respectively, one gear and the other gear A vertical step is formed in the portion of the peak where the peak and the valley of the drive face each other, and the step of the drive receiving step gear and the step of the drive step gear contact each other when the electrostatic latent image holding member is driven. Is. As a result, when the electrostatic latent image holder is driven, the electrostatic latent image holder can always be accurately positioned with respect to the image forming apparatus main body.

The invention according to claim 3 is an electrostatic latent image carrier,
Image a process unit that incorporates a charger that charges the surface of the electrostatic latent image carrier and a developer that develops the electrostatic latent image formed on the surface of the electrostatic latent image carrier with toner to make it visible. In the image forming apparatus detachably provided in the forming apparatus main body,
A step gear consisting of two gears is used as a drive receiving gear of the electrostatic latent image holding member, and meshes with the drive receiving step gear of the electrostatic latent image holding member when the process unit is attached to the image forming apparatus main body. A drive stage gear consisting of two gears is provided, and the drive receiving stage gear and the drive stage gear are configured to be in close contact by shifting the phases of the teeth of the two gears respectively, and one gear and the other gear are In the mountain portion of the teeth on the opposite side, an inclined portion is formed so as to form a V shape between the mountain portion of one gear and the mountain portion of the other gear, and the mountain of one gear and the other gear is formed. Section and valley section form a vertical step in the area where the sloped section of the mountain section is opposite to each other, and when driving the electrostatic latent image holder, the step section of the drive receiving step gear and the step section of the driving step gear contact each other. It comes into contact.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of the image forming apparatus.
2 is provided detachably. The process unit 12
Is provided with a photosensitive drum 13 which is an electrostatic latent image holder, a charger 14 for uniformly charging the surface of the photosensitive drum 13 around the photosensitive drum 13, and a surface of the photosensitive drum 13 formed by exposure. Toner is attached to the electrostatic latent image thus developed to develop and visualize the electrostatic latent image, a static elimination lamp 16 for neutralizing the surface of the photosensitive drum 13 after transfer, and a residual toner on the surface of the photosensitive drum 13 after transfer. A cleaning device 17 for removing toner is arranged.

An exposure device 18 is arranged above the process unit 12. The exposure device 18 is composed of, for example, a laser scanner, and scans a laser beam to record image information on the surface of the photosensitive drum 13 charged by the charger 14 as an electrostatic latent image. A transfer roller 19 is arranged below the process unit 12 in contact with the photosensitive drum 13.

The developing device 15 is provided with a developing roller 20 and a toner supply roller 21, and the toner supplied from the toner storage chamber 22 is transferred to the developing roller 20 by the toner supply roller 21.
To be supplied. The toner conveyed by the developing roller 20 is regulated to a constant layer thickness by the toner layer thickness regulating member 23 on the way, so that the amount of toner attached to the photosensitive drum 13 is always constant. The toner in the toner storage chamber 22 is stirred by the stirring member 24.

The main body 11 of the image forming apparatus is provided with a paper feed cassette 25 at the bottom thereof, and the paper feed cassette 25 is used during image formation.
From the paper feed roller 26, the transfer paper 27 is sent out one by one. Then, the transfer paper 27 sent out
Is fed between the photosensitive drum 13 and the transfer roller 19 via the feed roller 28. Transfer paper 2 fed between the photosensitive drum 13 and the transfer roller 19
A toner image 7 visualized by the developing device 15 is transferred by the action of the transfer roller 19, and the transfer paper 27 after the transfer is completed.
After being heat-fixed by the heat fixing device 29, it is discharged onto the upper surface of the image forming apparatus main body 11 via the feed rollers 30 and 31.

FIG. 2 is a sectional view showing the mounting structure of the photosensitive drum 13 of the process unit 12 and the main body 11 of the image forming apparatus. A flange 32a and a drive receiving step gear 33 are fixed to one end of the photosensitive drum 13, Flange 32b on the other end
Is fixed. Case 3 of the process unit 12
The drum positioning pin 3 on one side cover 34a
5, the drum positioning pin 35 is fitted in the central hole of the drive receiving step gear 33 and the central hole of the flange 32a, and the positioning pin 36 is formed from the other side cover 34b of the case 34 to the flange 32b. The photosensitive drum 13 is rotatably supported in the case 34 of the process unit 12 by being fitted in the center hole of the process unit 12.

Then, the positioning bosses 37a, 37b provided on the side covers 34a, 34b of the case 34 of the process unit 12 are inserted from above into the positioning grooves 38a, 38b of the process unit 12 provided on the main body 11 of the image forming apparatus. And the positioning bosses 37a, 37
The upper part of b is pressed and fixed by the leaf springs 39a and 39b. A motor (not shown) is provided in the image forming apparatus main body 11.
When the process unit 12 is mounted on the image forming apparatus main body 11, a drum driving step gear 40 that is a driving step gear that rotates by the drum driving step gear 4 is provided.
0 and the drive receiving step gear 33 mesh with each other.

The drive receiving step gear 33 and the drum driving step gear 40 are of the same module as shown in a perspective view of FIG. 3, a sectional view taken along line AA of FIG. 3 and a side view of FIG. Two
The spur gears 41 and 42 are closely contacted with each other by shifting the phase of their teeth by ½ pitch. Then, the tooth crest portion 41 on the side where the one gear 41 and the other gear 42 face each other.
In the a and 42a, the inclined portions 41b and 42b are formed so that the mountain portion 41a of the one gear 41 and the mountain portion 42a of the other gear 42 form a V shape. Furthermore, one gear 4
A vertical step portion 41c is formed in a portion following the inclined portion 41b formed in the first mountain portion 41a, and a vertical step portion 42c is formed in a portion following the inclined portion 42b formed in the mountain portion 42a of the other gear 42. ing.

In such a structure, when the process unit 12 is mounted on the image forming apparatus main body 11, the upper half of the case of the image forming apparatus main body 11 is opened upward as shown in FIG. 12 is attached to a predetermined position of the image forming apparatus main body 11. That is, each side cover 34 of the case 34 of the process unit 12 is inserted into the positioning grooves 38a and 38b provided in the main body 11 of the image forming apparatus.
Positioning bosses 37a and 37b provided on a and 34b are inserted and fitted from above, and the positioning bosses 37a and 37b are inserted.
The upper part of is fixed by pressing the leaf springs 39a and 39b.

At this time, the drum driving step gear 40 provided on the image forming apparatus main body 11 side and the drive receiving step gear 33 provided on the photosensitive drum 13 are engaged with each other, but as shown in FIG. Drive gear 40 and drive receiving gear 33
Even if the gears are slightly misaligned with each other, the inclined portions 41b and 42b formed on the gears 41 and 42 of the drive receiving step gear 33 and the inclined portions 41 formed on the gears 41 and 42 of the drum driving step gear 40, respectively.
b and 42b are brought into contact with each other to move in the axial direction and mesh with each other so as to correct the deviation. In this way, the drum driving step gear 40 and the drive receiving step gear 33 are accurately meshed with each other as shown in FIG. 6 (b).

When the two gears 33, 40 mesh with each other, the step portion 4 formed on the gears 41, 42 of the drive receiving step gear 33.
1b and 42b and gears 41 and 4 of the drum driving step gear 40
The stepped portions 41b and 42b formed in 2 come into contact with each other to position the drum driving step gear 40 and the drive receiving step gear 33. In this way, by mounting the process unit 12 on the image forming apparatus main body 11, the photosensitive drum 13 can be positioned with respect to the image forming apparatus main body 11.

The rotation of the photosensitive drum 13 is carried out by rotating a drum driving step gear 40 by a motor provided on the image forming apparatus main body 11 side and transmitting this rotation to a drive receiving step gear 33. Since the driving force in the thrust direction is not generated in 33 and 40 unlike the case of the helical gear, the driving force is not dispersed and a high transmission efficiency of the driving force can be obtained.

The meshing ratio of the step gear will be described below.
In the involute gear, the tooth flanks of the drive gear and the driven gear move on a tangent line sandwiching the center lines of the basic circles of the two gears. The contacts come in contact with each other on the line of action, and the contacts unilaterally move in accordance with the rotation to transmit power. For this reason, the pitch on the basic circle (normal pitch) is a condition that the pair of gears mesh correctly.
The absolute condition is that t e are equal. In Fig. 8, the length on the line of action is the length of meshing (the length between Pa and Pb)
Then, the value obtained by dividing the length of this mesh by the normal pitch te is the mesh ratio. That is, the mesh ratio ε = the mesh length (Pa
~ Pb) / normal pitch te.

In this embodiment, the drive receiving step gear 3 is used.
3. Since both the spur gears 41 and 42 of the same module have a structure in which the phase of the teeth of each of them is shifted by 1/2 pitch in both of the drum driving step gears 40, one gear always has a trough portion of the other. The peaks of the gears overlap. When the meshed gears are viewed from the axial direction of the gears, if the peaks and valleys mesh at the meshing points of the gears, the valleys and peaks mesh at the meshing points on the back side thereof.

As a result, the meshing ratio is doubled as compared with the case where only one spur gear is used, whereby the meshing between the drive receiving stage gear 33 and the drum driving stage gear 40 becomes very large. It becomes smooth and the fluctuation of the transmission torque can be suppressed to 1/2. Therefore, it is possible to prevent image jitter failure and image pitch unevenness due to rotation fluctuation of the photosensitive drum 13. That is, good image formation can be performed.

The meshing ratio of a normal spur gear is about 1.8, and the meshing ratio of a stepped gear is twice that. Therefore, a meshing ratio of about 3.6 can be expected. This means that 3 or 4 teeth are always meshed with each other, so that the load carried by one tooth can be reduced and the deflection can be reduced. In particular, it is necessary for the photosensitive drum 13 to suppress the rotation fluctuation, and this can be sufficiently dealt with. Therefore, even if a plastic gear is used as the drive receiving step gear 33 and the drum driving step gear 40, it is possible to sufficiently prevent the image jitter defect and the image pitch unevenness due to the rotation fluctuation of the photosensitive drum 13.

In this embodiment, as the drive receiving stepped gear 33 and the drum driving stepped gear 40, two spur gears of the same module which are closely contacted with their teeth shifted by 1/2 pitch are used. However, the present invention is not necessarily limited to this. For example, as shown in FIG. 9, it is also possible to use a module in which two gears 51 and 52 which are different from each other in integral multiples are closely contacted to form a stepped gear. That is, in this stepped gear, the number of teeth of each gear 51, 52 is in a relation with an integer value as a common divisor. By using such a step gear as a drive receiving step gear and a drum driving step gear, the width in the longitudinal direction of the photosensitive drum, that is, the width of the process unit can be shortened, and the process unit can be made more compact. That is, since the bending strength of the root of the tooth is generally proportional to the module, if the distributed load of the larger gear of the module is made equal to the distributed load of the smaller gear of the module, the tooth thickness of the larger gear of the module Can be made an integral multiple thinner than the smaller gear of the module. Therefore, if this step gear is used as a drive receiving step gear, the width of the photosensitive drum in the longitudinal direction can be shortened by making the gear of the larger module thinner.

Further, for example, as shown in FIG. 10, two helical gears 61 and 62 of the same module having the same helix angle and the opposite helix directions are phase-shifted and closely contacted to each other. May be used. This step gear can be regarded as a kind of helical gear. In the case of this step gear, it is possible to increase the meshing ratio to 2 or more with only one helical gear. By shifting the phase of two helical gears to form a step gear, the meshing ratio can be increased. It is possible to set it to 4 or more. Therefore, the load distribution of one tooth can be further dispersed, the deflection of the gear can be further reduced by the load, and the photosensitive drum can be rotated more smoothly.

In particular, as shown in FIG. 11, the tooth width b of the helical gear is the axial pitch ta of the helical teeth ta = πm / sin β.
(However, when m is a module and β is a helix angle), the total length of the simultaneous contact lines on the tooth surface is always constant, which reduces fluctuations in tooth deflection and results in quiet and smooth rotation. You can Further, in the case of the helical gear, since the directions of the helix angles are opposite to each other, the thrust forces that are the transmission loss of the driving force cancel each other out, so that the photosensitive drum can be positioned without shifting to one side, and , Smooth rotation is possible without generating resistance on the sliding surface in the thrust direction.

[0032]

As described above, according to the first aspect of the invention, an image in which a process unit in which an electrostatic latent image holding member, a charger, a developing device and the like are integrally incorporated is detachably provided in the image forming apparatus main body. In the forming apparatus, by using the step gear as the drive receiving gear of the electrostatic latent image holding member and the image forming apparatus main body side driving gear, the transmission efficiency of the driving force can be improved and the meshing ratio can be increased. As a result, the rotation of the electrostatic latent image carrier becomes smooth and good image formation is possible, and moreover, the meshing of the drive receiving step gear and the drive step gear when mounting the process unit in the image forming apparatus main body Can be done accurately.

According to the second aspect of the present invention, the image forming apparatus has a process unit in which an electrostatic latent image holding member, a charging device, a developing device and the like are integrally incorporated and which is detachably provided in the image forming device main body. In the above, by using the step gear as the drive receiving gear of the electrostatic latent image holding member and the image forming apparatus main body side driving gear, the transmission efficiency of the driving force can be increased and the meshing ratio can be increased. , The positioning of the electrostatic latent image holder with respect to the main body of the image forming apparatus can always be accurately performed,
As a result, the rotation of the electrostatic latent image holder is further smoothed, and a better image can be formed.

Further, according to the third aspect of the invention, the image forming apparatus in which the process unit having the electrostatic latent image holding member, the charger, the developing device and the like integrally incorporated therein is detachably provided in the image forming apparatus main body. In the above, by using the step gear as the drive receiving gear of the electrostatic latent image holding member and the image forming apparatus main body side driving gear, the transmission efficiency of the driving force can be increased and the meshing ratio can be increased. Positioning of the electrostatic latent image holder with respect to the main body of the image forming apparatus can always be performed accurately, which allows smoother rotation of the electrostatic latent image holder for better image formation, and the process unit to form an image. It is possible to accurately engage the drive receiving step gear and the drive step gear when mounted on the apparatus body.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the invention.

FIG. 2 is a sectional view showing a mounting structure of the photosensitive drum of the process unit and the image forming apparatus main body in the same embodiment.

FIG. 3 is a perspective view of a drive receiving step gear and a drum driving step gear in the same embodiment;

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a side view of the drive receiving step gear and the drum driving step gear in the same embodiment;

FIG. 6 is a view for explaining the meshing operation of the drive receiving step gear and the drum driving step gear when the process unit is mounted in the embodiment.

FIG. 7 is a diagram showing a state when the process unit is attached to the image forming apparatus main body in the same embodiment.

FIG. 8 is a diagram for explaining meshing of gears.

FIG. 9 is a perspective view showing another embodiment of the drive receiving step gear and the drum driving step gear.

FIG. 10 is a perspective view showing another embodiment of the drive receiving step gear and the drum driving step gear.

FIG. 11 is a diagram for explaining the length of contact engagement in a helical gear.

FIG. 12 is a partial cross-sectional view showing a conventional example.

[Explanation of symbols]

 11 ... Image forming apparatus main body 12 ... Process unit 13 ... Photosensitive drum (electrostatic latent image holder) 14 ... Charger 15 ... Developer 33 ... Drive receiving step gear 40 ... Drum driving step gear 41, 42 ... Spur gear

Claims (3)

[Claims] 1. An electrostatic latent image holder, a charger for charging the surface of the electrostatic latent image holder, and an electrostatic latent image formed on the surface of the electrostatic latent image holder is developed with toner to visualize the latent image. In an image forming apparatus in which a process unit having a developing device integrated therein is detachably provided in an image forming apparatus main body, a stepped gear consisting of two gears is used as a drive receiving gear of the electrostatic latent image holding member. Then, the image forming apparatus main body is provided with a drive step gear consisting of two gears that mesh with the drive step gear of the electrostatic latent image holding member when the process unit is attached, and the drive step gear is provided. And drive gears are 2
The teeth of the gears are arranged in close contact by shifting the phases of the gears, and one of the gears has a mountain portion of the teeth on the side where the other gear faces each other. An image forming apparatus characterized in that an inclined portion is formed so as to form a V shape. 2. An electrostatic latent image holding member, a charger for charging the surface of the electrostatic latent image holding member, and an electrostatic latent image formed on the surface of the electrostatic latent image holding member is developed with toner to visualize it. In an image forming apparatus in which a process unit having a developing device integrated therein is detachably provided in an image forming apparatus main body, a stepped gear consisting of two gears is used as a drive receiving gear of the electrostatic latent image holding member. Then, the image forming apparatus main body is provided with a drive step gear consisting of two gears that mesh with the drive step gear of the electrostatic latent image holding member when the process unit is attached, and the drive step gear is provided. And drive gears are 2
The tooth tips of the two gears are closely contacted by shifting the phases of the tooth tips, and a vertical step portion is formed at the peak portion where the peak portion and the valley portion of one gear and the other gear face each other, and the electrostatic latent image is formed. An image forming apparatus, wherein the drive receiving step gear and the step portion of the driving step gear contact each other when the holding body is driven. 3. An electrostatic latent image holder, a charger for charging the surface of the electrostatic latent image holder, and an electrostatic latent image formed on the surface of the electrostatic latent image holder is developed with toner to be visualized. In an image forming apparatus in which a process unit having a developing device integrated therein is detachably provided in an image forming apparatus main body, a stepped gear consisting of two gears is used as a drive receiving gear of the electrostatic latent image holding member. Then, the image forming apparatus main body is provided with a drive step gear consisting of two gears that mesh with the drive step gear of the electrostatic latent image holding member when the process unit is attached, and the drive step gear is provided. And drive gears are 2
The teeth of the gears are arranged in close contact by shifting the phases of the gears, and one of the gears has a mountain portion of the teeth on the side where the other gear faces each other. The inclined portion is formed so as to form a V shape, and a vertical step portion is formed at a portion following the inclined portion of the mountain portion where the mountain portion and the valley portion of one gear and the other gear face each other, and An image forming apparatus, wherein the drive receiving step gear and the step portion of the drive step gear contact each other when the latent image holding member is driven.