JPH08234643A - Image forming machine - Google Patents

Abstract

PURPOSE: To prevent the driving of a developer applying means, when a photoreceptor is driven to reversely rotate by disposing a coupling having a prescribed backlash corresponding to a prescribed rotation angle at which the photoreceptor is driven to reversely rotate, in a power transmitting mechanism. CONSTITUTION: An electrically driven motor 11 is driven to reversely rotate, so that a first gear 152 constituting the coupling gear 150 of a second power transmitting mechanism 13 is driven in an opposite direction. But engaging projecting parts 155 and 156 constituting the coupling 154 and engaging projecting parts 157 and 158 provided on the end surface of a second gear 153 have a backlash by the prescribed rotation angle corresponding to the reverse rotary driving quantity of the photoreceptor 2, so that from the second gear 153 to a gear to be driven in the second power transmitting mechanism 13, reverse rotary driving can not occur. Therefore, even if the electrically driven motor 11 is driven to reversely rotate the photoreceptor 2, for the reverse rotary driving of the photoreceptor 2, the developer applying means 52 is never driven to reversely rotate. Since a one-way clutch 190 is disposed between an intermediate gear 170 and a fixed gear 171, a roller is never driven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming machine such as an electrophotographic apparatus or an electrostatic recording apparatus, and more specifically, a front edge portion is pressed against the surface of a photosensitive member which moves with residual developer adhered thereto. The present invention relates to an image forming machine provided with a cleaning blade that is disposed as a unit.

[0002]

2. Description of the Related Art In an image forming machine such as an electrophotographic device or an electrostatic recording device, an electrostatic latent image corresponding to an original image is formed on a surface of a photoconductor, and the electrostatic latent image is developed into a toner image by a developing device. After the development, the toner image is transferred onto a transfer paper. However, when transferring the toner image to the transfer paper, not all of the toner adhering to the surface of the photoconductor is transferred to the transfer paper, and some toner adheres to the surface of the photoconductor as residual toner. It remains as it is. Therefore, the image forming machine is provided with a cleaning device for removing the residual toner adhering to the surface of the photoconductor prior to the next electrostatic latent image formation. As this kind of cleaning device, a blade cleaning system is generally used, which is provided with a cleaning blade which is arranged with its tip edge portion pressed against the surface of a photosensitive member that moves with residual toner attached.

However, the blade cleaning method is
Since the cleaning blade made of a flexible material such as rubber is pressed against the surface of the photoconductor, toner is always present between the cleaning blade and the surface of the photoconductor. This toner has a property of aggregating and fusing by heat or pressure, and the aggregating toner adheres to the edge portion of the cleaning blade that is in contact with the surface of the photosensitive member, and affixes when the contact pressure increases, and the cleaning performance deteriorates. There is a problem that black streaks appear in the axial direction of the photoconductor drum, which is called a mark. In order to solve such a problem, a magnetic roller is provided on the upstream side of the cleaning blade, and the photoconductor is reversely controlled so that the contact portion of the surface of the photoconductor with the cleaning blade returns to the position of the magnetic roller after completion of copying. The technique is disclosed in JP-A-58-34477.

[0004]

Therefore, in the image forming machine provided with the driving means in which the photosensitive member and the developer applying means of the developing device are rotationally driven by the common driving source, the photosensitive member is exposed after the image forming operation is completed. When the drive source is rotated in the reverse direction to drive the body drum in the reverse direction, the developer applying unit of the developing device is also driven in the reverse direction. When the developer application means is reversed,
Problems such as scattering of the toner attached to the developer applying means occur. In order to solve such a problem, it is conceivable to dispose an electromagnetic clutch in a power transmission mechanism that transmits power to the developer applying unit, but there is a problem in that the use of the electromagnetic clutch makes it expensive.

Further, in the case where the photoconductor and the developer applying means of the developing device are in contact with each other, when the photoconductor drum is reversely driven after the image forming operation is completed, the developer applying means is also applied. It is driven and reversely driven. When the developer applying unit is reversed, problems such as scattering of toner attached to the developer applying unit occur.

The present invention has been made in view of the above points, and its main technical problem is to form an image with a power transmission mechanism for driving a photoreceptor and a developer applying means of a developing device by a common drive source. An image forming machine equipped with an inexpensive power transmission mechanism capable of maintaining a stopped state without reversely driving the developer applying means even if the photosensitive drum is reversely driven after the image forming operation is completed. To do.

Further, according to the present invention, in the image forming machine in which the photosensitive member and the developer applying means of the developing device are in contact with each other, even if the photosensitive drum is reversely driven after the image forming operation is completed, An object of the present invention is to provide an image forming machine provided with a power transmission mechanism that can maintain a stopped state without being driven in reverse by the applying means and driven in the reverse direction.

[0008]

In order to achieve the above main technical problems, according to the present invention, a photoconductor and a developing device having a developer applying means for forming a toner image on the photoconductor, A common drive source for rotationally driving the photoconductor and the developer applying means of the developing device, a first power transmission mechanism for transmitting the power of the drive source to the photoconductor, and the power of the drive source. A second power transmission mechanism for transmitting the toner to the developer applying means of the developing device, and a cleaning blade disposed with the tip edge portion pressed against the surface of the photosensitive member. In an image forming machine that reversely drives the driving source to reversely rotate the photosensitive member by a predetermined rotation angle, a coupling having a predetermined play corresponding to the predetermined rotation angle is provided in the second power transmission mechanism. , An image forming machine characterized by That.

According to the present invention, the rotation restricting means for restricting the rotation in the direction opposite to the predetermined direction is included in the power transmission mechanism that power-connects the coupling and the developer applying means in the second power transmission mechanism. An image forming machine provided with is provided.

[0010]

In the image forming machine according to the present invention, when the drive source is reversely driven after the image forming operation is completed, the photosensitive member is reversely driven through the first power transmission mechanism. On the other hand, in the second power transmission mechanism that transmits the power of the drive source to the developer applying means of the developing device, a coupling having a predetermined play corresponding to a predetermined rotation angle at which the photoconductor is reversely driven is provided. Since it is provided, the developer applying means is not driven and the stopped state is maintained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A more detailed description will be given below with reference to the accompanying drawings showing a preferred embodiment of an image forming machine constructed according to the present invention.

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming machine according to the present invention, and FIG. 2 is a drive unit for driving a photosensitive member of the image forming machine shown in FIG. 1 and a developer applying means of a developing device. FIG. 3 is a plan view showing the power transmission mechanism of the drive unit shown in FIG.

The image forming machine shown in FIG. 1 comprises a photoconductor 2 which is detachably mounted in a unit housing (not shown). The photoconductor 2 is composed of a rotary drum 22 having a rotary shaft 21 and a photosensitive layer 23 mounted on the outer peripheral surface of the rotary drum 22, and is indicated by an arrow A at the time of image formation via a driving device described later. It is driven to rotate in the direction shown,
After the image formation is completed, it is driven in the reverse direction by a predetermined rotation angle in the direction opposite to arrow A. Photoreceptor 2 configured in this way
Around the circumference of the, as seen in the direction of rotation indicated by the arrow A,
A charging corona discharger 3, an exposure unit 4, a developing device 5, a transfer corona discharger 6, a peeling corona discharger 7, a cleaning device 8, and a charge eliminating lamp 9 are provided. The charging corona discharger 3 charges the photosensitive layer 23 of the photosensitive member 2 to a predetermined polarity, and determines the electrostatic latent image formed on the photosensitive layer 23 by the exposing means 4 and its potential. In the illustrated embodiment, the (+) power source (not shown) is connected. The polarity of the power source is not limited to (+) but is set according to the type of photoconductive material forming the photosensitive layer 23 of the photosensitive member 2.

The developing device 5 is provided with a developing housing 51 which can be made of synthetic resin. Inside the developing housing 51, a developer applying means 52, a supplying means 53, a stirring means 54 and a regulating means 55. Is provided. Further, although not shown, the development housing 51
A toner cartridge containing toner is attached to the. The developer applying means 52 is the developing housing 51.
It includes a rotary shaft 521 rotatably mounted between the both side walls and a roller 522 fixed to the rotary shaft 521. The rotating shaft 521 can be formed from a suitable metal material such as stainless steel. The roller 522 is made of a relatively flexible and conductive material, for example, a conductive solid rubber such as urethane rubber. Roller 522
Has a hardness of about 60 to 80 in Asker C hardness, and the volume electric resistance of the roller 522 is 10 ^{6 to} 10 ⁹ Ω · cm.
It is preferably about the same. The roller 522 of the developer applying unit 52 is exposed through an opening formed in the developing housing 51 to face the photoconductor 2, and its peripheral surface is pressed against the peripheral surface of the photosensitive layer 23 of the photoconductor 2.
In this pressure contact area, the peripheral surface of the roller 522 is slightly elastically compressed. The rotary shaft 521 of the developer applying unit 52 is rotationally driven in a direction indicated by an arrow B at the time of image formation via a driving device described later. Rotating shaft 5
By the above rotation of the roller 21, the roller 522 is also continuously driven to rotate in the direction indicated by the arrow B during image formation, and the peripheral surface thereof is sequentially conveyed through the developer holding area 525, the developer regulating area 526 and the developing area 527. In the illustrated embodiment, the rotary shaft 5 of the developer applying means 52 is used during image formation.
A bias voltage of the (+) electrode is applied to 21.

The supplying means 53 is a rotary shaft 531 rotatably mounted between the side walls of the developing housing 51.
And an auxiliary roller 522 fixed to the rotating shaft 531. The auxiliary roller 532 is preferably made of foam such as foamed silicone or foamed urethane. The auxiliary roller 532 is pressed against the roller 522 of the developer applying unit 52. The hardness of the foam forming the auxiliary roller 532 is considerably lower than the hardness of the roller 532 (for example, Asker C hardness is about 35), and the auxiliary roller 532 is pressed against the roller 522, so that the auxiliary roller 532 is pressed in the contact area. .15 to 0.2
It is desirable to be elastically compressed by about 5 mm. The auxiliary roller 532 is continuously driven to rotate in the direction indicated by arrow C by a driving unit (not shown). The stirring means 54 includes a rotating shaft 541 rotatably mounted between both side walls of the developing housing 51, and the rotating shaft 541.
And an agitating member 542 fixed to the shaft, and is continuously driven to rotate in a direction indicated by an arrow D by a driving unit (not shown).

The regulating means 55 is a blade 551 made of a rigid member which is pressed against the peripheral surface of the roller 522 of the developer applying means 52, and one side of the blade 551 is moved in the direction of pressing against the peripheral surface of the roller 522. It is provided with a blade supporting means 552 that supports the blade 551 and an elastic biasing means 553 that presses the surface of the blade 551 in a direction of pressing against the peripheral surface of the roller 522. At least one surface (that is, the surface pressed against the peripheral surface of the roller 522) of the blade 551 made of the rigid member extends in the width direction (direction perpendicular to the paper surface in FIG. 1) along the peripheral surface of the roller 522. It is composed of a flat plate member. The surface roughness of at least a region of one surface of the blade 551 which is pressed against the peripheral surface of the roller 522 is sufficiently small, and the center line average roughness Ra defined by JIS B 0601 is 6.00 or less, particularly 0.20. It is preferably below 0.02. If the surface roughness of one side of the blade 551 becomes excessive, the developer applying unit 5
The surface of the thin layer of the developer formed on the peripheral surface of the second roller 522 is not sufficiently flattened and tends to be non-uniform. Therefore, as a suitable rigid material having a sufficiently small surface roughness and high hardness and abrasion resistance even though the blade 551 can be formed relatively inexpensively, a commercially available plate glass is used. Can be mentioned. The plate glass may have a thickness of about 3 mm.

Next, the cleaning device 8 will be described. The cleaning device 8 includes a cleaning blade 82, which is disposed with the tip edge portion pressed against the outer peripheral surface of the photoconductor 2.
Is provided. The cleaning blade 82 is made of an elastic material such as rubber and is attached to a blade holder 83 attached to the cleaning housing 81. A cleaning roller 84 for collecting the paper powder and dust adhering to the outer peripheral surface of the photoconductor 2 is disposed on the upstream side of the cleaning blade 82. The cleaning roller 84 includes a rotating shaft 8 made of metal such as steel.
41, and a sponge-like roller portion 842 mounted on the outer peripheral surface of the rotating shaft 841 with an adhesive,
The outer peripheral surface of the roller portion 842 is arranged in contact with the outer peripheral surface of the photoconductor 2. The roller portion 842 is formed of a foam material such as urethane foam or silicon foam. The cleaning roller 84 configured as described above
Is indicated by an arrow E by a driving unit (not shown) during image formation.
It is driven to rotate in the direction shown by. In the cleaning housing 81, there is provided a scraping plate 85 which comes into contact with the outer peripheral surface of the cleaning roller 84 and scrapes off the toner adhering to the cleaning roller 84, and the toner scraped off by the scraping plate 85. A conveying screw 86 for conveying the toner to a toner collecting container (not shown) is provided. The conveying screw 86 is rotationally driven in the direction indicated by arrow F by a driving means (not shown). Further, a lower blade 87 is arranged on the upstream side of the cleaning roller 84, and is attached to the cleaning housing 81 via an appropriate attachment member.

Next, the photoconductor 2 and the developer applying means 5
2 to 4 of the drive device 10 for rotating the drive unit 2.
Refer also to the explanation. The drive device 10 includes an electric motor 11 that is a common drive source in the illustrated embodiment, a first power transmission mechanism 12 that transmits the power of the electric motor 11 to the rotary shaft 21 of the photoconductor 2, and an electric motor. Second for transmitting the power of the motor 11 to the rotary shaft 521 of the developer applying unit 52
The power transmission mechanism 13 of FIG. The electric motor 11
A drive gear 112 is mounted on the rotary drive shaft 111. The first power transmission mechanism 12 includes the drive gear 112.
A first intermediate gear 12 including a large gear 121 power-transmitted to and a small gear 122 integrally formed with the large gear 121.
0, a second intermediate gear 130 that is drivingly connected to the pinion gear 122 of the first intermediate gear 120, and a driven member that is mounted on the rotary shaft 21 of the photoconductor 2 and that is drivingly connected to the second intermediate gear 130. And a gear 140. The second power transmission mechanism 13 includes a coupling gear 150 that is drivingly connected to the drive gear 112, and the coupling gear 15
A third intermediate gear 1 including a large gear 161 that is transmission-coupled to 0 and a small gear 162 integrally formed with the large gear 161.
60, a fourth intermediate gear 170 drivingly connected to the small gear 162 of the first intermediate gear 160, and the fourth intermediate gear 17 mounted on the rotary shaft 521 of the developer applying means 52.
0 and a driven gear 180 that is drivingly connected.

The coupling gear 150 has a fixed shaft 1
51 includes a first gear 152 rotatably arranged on the fixed shaft 151 and meshed with the drive gear 112, and a second gear 153 rotatably arranged on the fixed shaft 151 and meshed with the large gear 161 of the intermediate gear 160. are doing. On the end face of the first gear 152, the engagement protrusion 15 that constitutes the coupling 154 is formed.
5, 156 are provided. The engagement protrusions 155, 15
6 is provided with a phase angle of 180 °. on the other hand,
Also on the end surface of the second gear 153, the engaging portions 155, 1
Engagement protrusions 157 and 158, which are formed with a phase angle of 180 ° that form 56 and the coupling 154, are provided. The engaging projections 155, 156 provided on the end surface of the first gear 153 and the engaging projections 157, 158 provided on the end surface of the second gear 153 are arranged to face each other. They are assembled so as to be out of phase with each other, and are engaged with each other with play of a predetermined rotation angle so as to be transmission-coupled. The play at the predetermined rotation angle corresponds to the amount by which the photoconductor 2 is reversely driven in the direction opposite to the arrow A by the predetermined rotation angle after the image forming operation is completed.

In the illustrated embodiment, the fourth intermediate gear 170 and the fixed shaft 171 on which the intermediate gear 170 is mounted.
A one-way clutch 190 is arranged between the two. The one-way clutch 190 allows the fourth intermediate gear 170 to be rotationally driven in the direction indicated by the arrow by the driving force of the electric motor 11, but functions as a rotation restricting unit that restricts rotation in the direction opposite to the arrow. . In the illustrated embodiment, the one-way clutch 190 is arranged between the fourth intermediate gear 170 and the fixed shaft 171.
The rotation restricting means including a one-way clutch may be provided in the power transmission mechanism from the coupling 154 to the rotary shaft 521 of the developer applying means 52.

The image forming machine according to the present invention is configured as described above, and its operation will be described below. At the time of image formation, the charging corona discharger 3, the exposing means 4,
Corona discharger 6 for transfer, corona discharger 7 for peeling, discharge lamp 9, cleaning roller 84 of cleaning device 8
The transport screw 86 and the like are operated, and the electric motor 11 of the drive device 10 is rotationally driven in the forward direction indicated by the arrow G. When the electric motor 11 is rotationally driven in the direction of arrow G, the photoconductor 2 is rotationally driven in the direction of arrow A via the first power transmission mechanism 12 and also via the second power transmission mechanism 13. The roller 522 of the developer applying unit 52 is rotationally driven in the direction indicated by arrow B. Further, the auxiliary roller 532 and the agitating means 54 of the supplying means 53 are rotationally driven in the directions indicated by arrows by driving means not shown. The roller 522 of the developer applying unit 52 is continuously driven to rotate in the direction indicated by the arrow B, and the auxiliary roller 532 of the supplying unit 53 acts on the roller 522 in the developer holding area 525, and the roller 522 is used until then.
The developer retained on the peripheral surface of the roller 522 is peeled off from the roller 522, and the developer is newly supplied to the peripheral surface of the roller 522. In the developer regulation area 526, the blade 551 of the regulation means 55 acts on the developer retained on the peripheral surface of the roller 522 to regulate the developer retained on the peripheral surface of the roller 522 to a required amount. Form a thin layer. Further, by the action of the blade 551, the toner constituting the developer is frictionally charged to have a predetermined polarity, for example, a positive polarity. Next, in the developing area 527, a developer is applied to the electrostatic latent image on the photoconductor layer provided on the peripheral surface of the photoconductor 2 to develop the electrostatic latent image into a toner image. For example, the electrostatic latent image has a non-image area charged to about + 700V and an image area charged to about + 120V, and toner is attached to the image area (so-called reversal development). The photoconductor 2 is continuously driven to rotate in the direction indicated by the arrow A in FIG.
7, the peripheral surface of the photoconductor 2 and the peripheral surface of the roller 522 of the developer applying unit 52 are moved in the same direction.
The moving speed V2 of the peripheral surface of the roller 522 is set to be somewhat higher than the moving speed V1 of the peripheral surface of the rotary drum 1, and it is preferable that 1.5V1 ≦ V2 ≦ 2.2V1. In this case, the roller 522 causes the developing area 527
In addition to the sufficient amount of developer being conveyed, the toner once attached to the non-image portion of the electrostatic latent image is appropriately peeled off due to the sliding action of the peripheral surface of the roller 522 with respect to the peripheral surface of the photoreceptor 2. It is possible to obtain a good toner image having a developing density and no fog. As the developer, the volume average particle diameter (Vol. 50%: the volume of the toner having the volume average particle diameter or less and the volume of the toner having the volume average particle diameter or more are the same) is 8.0.
To about 12.0 μm and volume electric resistance of 10 ⁸ Ω ・
A developer consisting only of toner having a size of not less than cm is preferably used. On the other hand, the transfer paper is supplied between the photoconductor 2 and the corona discharger 6 for transfer by a transfer paper supply device (not shown), and the transfer paper and the photosensitive layer 23 of the photoconductor 2 on which the toner image is formed are transferred. The toner image is transferred by passing through the corona discharger 6. The transfer paper on which the toner image is transferred and electrostatically attracted to the photoconductor 2 to move is peeled off by corona discharge from the peeling corona discharger 7, then fixed by a fixing unit (not shown), and discharged from a discharge roller. To be done. Further, when passing through the cleaning roller 84 of the cleaning device 8, the photoconductor 2 that has completed the transfer process as described above collects paper dust and dust adhering to the outer peripheral surface of the photoconductive layer 23, Further, the cleaning blade 82 scrapes off the residual toner adhering to the outer peripheral surface of the photosensitive layer 23. The scraped toner adheres to the cleaning roller 84, rotates, is scraped by the scraping plate 85, and is then carried to the toner collecting container (not shown) by the carrying screw 86. In this way,
The photoconductor 2 that has passed through the cleaning device 8 is further erased by the static elimination lamp 9 irradiating the photosensitive layer 23 with static elimination light.

The above is the image forming operation. Next, the operation immediately after the image forming operation is completed will be described. The image forming machine is equipped with a control unit (not shown), and this control unit first confirms whether or not the image forming operation is completed. The end of the image forming operation may be confirmed by a signal from a discharge switch that detects that the transfer sheet has passed the discharge roller, for example. In addition, a predetermined number (for example, 200)
It may be set when the signal from the discharge switch is confirmed after the transfer of the. In this way, when the end of the image forming operation is confirmed, the control means stops the electric motor 11 of the drive device 10. When the electric motor 11 is stopped, the photoconductor 2 and the developer applying unit 52 which are rotationally driven via the first power transmission mechanism 12 and the second power transmission mechanism 13 are stopped. When the photoconductor 2 and the developer applying unit 52 are stopped, the control unit drives the electric motor 11 in the reverse direction to the arrow G direction. When the electric motor 11 is driven in the reverse direction, the photoconductor 2 is driven in the reverse direction in the direction opposite to the arrow A through the first power transmission mechanism 12. The reverse drive amount of the photoconductor 2 is an amount until the position where the cleaning blade 82 of the photoconductor 2 is in contact with the cleaning roller 84 when the image forming operation is finished and the photoconductor 2 is stopped. Is a predetermined rotation angle corresponding to. When the photoconductor 2 is driven in the reverse direction, it is desirable that the cleaning roller 74 driven by a driving device (not shown) is rotationally driven in the direction opposite to the arrow E. That is, since the cleaning roller 84 is also reversely driven when the photoreceptor 2 is reversely driven, a large relative speed difference does not occur between the two, so that the photosensitive layer 23 of the photoreceptor 2 is not damaged. On the other hand, the electric motor 11
Is driven in the reverse direction, the first gear 152 forming the coupling gear 150 of the second power transmission mechanism 13 is driven in the direction opposite to the arrow, but the engaging protrusion 155 forming the coupling 154, Since the 156 and the engaging projections 157, 158 provided on the end surface of the second gear 153 are provided with a play by a predetermined rotation angle corresponding to the reverse drive amount of the photoconductor 2, the second power is generated. The second gear 153 in the transmission mechanism 13 to the driven gear 180 is not reversely driven. Therefore, even if the electric motor 11 is driven in reverse to drive the photoconductor 2 in reverse, the developer applying unit 52 is not driven in reverse. Also, as in the illustrated embodiment,
In an image forming machine equipped with a developing device of the type in which the roller 522 of the developer applying means 52 is pressed against the photosensitive layer 23 of the photoconductor 2, the roller 522 is driven when the photoconductor 2 is driven in the reverse direction as described above. However, in the illustrated embodiment, the one-way clutch 190 is provided between the fourth intermediate gear 170 that constitutes the second power transmission mechanism 13 and the fixed shaft 171. Since the rotation in the direction opposite to the arrow is restricted, the roller 522 is not driven.

In the illustrated embodiment, the image forming machine equipped with the developing device of the type in which the roller 522 of the developer applying means 52 is brought into pressure contact with the photosensitive layer 23 of the photosensitive member 2 has been described. The invention is not limited to an image forming machine equipped with a developing device of such a system,
It can also be applied to an image forming machine provided with a developing device in which the developer applying means is not in contact with the photoconductor. in this case,
It is possible to omit the one-way clutch 190, which is provided with the coupling 154 and serves as the rotation restricting means.

[0024]

The image forming machine according to the present invention is configured as described above, and is provided with a common drive source for driving the photoreceptor and the developer applying means of the developing device, and the drive source is provided after the image forming operation is completed. In the image forming machine that reversely drives the photoreceptor in the reverse direction by a predetermined rotation angle in a direction opposite to the predetermined direction, the predetermined rotation angle is provided in the second power transmission mechanism that transmits the power of the common drive source to the developer applying unit. Since a coupling with a predetermined play corresponding to is provided, the developer applying means is not driven even if the drive source is reversely rotated and the photoconductor is reversely driven after the image forming operation is finished, and the stopped state is maintained. can do. Therefore, it is possible to prevent the toner from scattering due to the reverse rotation of the developer applying unit during the reverse rotation of the photosensitive member.

Further, according to the present invention, the rotation restricting means for restricting the rotation in the direction opposite to the predetermined direction in the power transmission mechanism for transmitting and coupling the coupling and the developer applying means in the second power transmission mechanism. In the image forming machine equipped with the developing device of the type in which the developer applying means is pressed against the photoconductor, the developer applying means will be driven when the photoconductor is driven in reverse as described above. However, since the rotation is restricted by the rotation restricting means, the developer applying means is not driven even if the drive source is reversely rotated and the photoreceptor is reversely driven after the image forming operation is completed, and the stopped state is maintained. Can be maintained. Therefore, it is possible to prevent the toner from scattering due to the reverse rotation of the developer applying unit during the reverse rotation of the photosensitive member.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming machine configured according to the present invention.

FIG. 2 is a front view of a driving device for driving the photoconductor of the image forming machine and the developer applying unit of the developing device shown in FIG.

3 is a plan view showing the power transmission mechanism of the drive unit shown in FIG. 2 in a partially exploded state.

4 is an exploded perspective view showing a coupling gear arranged in the power transmission mechanism that constitutes the power transmission mechanism of the drive unit shown in FIG.

[Explanation of symbols]

 2: Photoconductor 3: Corona discharge device for charging 4: Exposure means 5: Developing device 6: Corona discharge device for transfer 7: Corona discharge device for peeling 8: Cleaning device 9: Elimination lamp 10: Driving device 11: Electric motor 12 : First power transmission mechanism 13: Second power transmission mechanism 21: Rotating shaft of photoconductor 22: Rotating drum 23: Photosensitive layer 51: Developing housing 52: Developer applying means 53: Supplying means 54: Stirring means 55: Regulation means 81: Cleaning housing 82: Cleaning blade 83: Blade holder 84: Cleaning roller 85: Scraping plate 86: Conveying screw 111: Electric motor rotation drive shaft 112: Drive gear 120: First intermediate gear 121: Large gear 122: Small gear 130: Second intermediate gear 140: Driven gear 150: Coupling gear 151: Fixed Shaft 152: First gear 153: Second gear 154: Coupling 155: Engagement protrusion 156: Engagement protrusion 157: Engagement protrusion 158: Engagement protrusion 160: Third intermediate gear 161: Large gear 162: Small gear 170: Fourth intermediate gear 171: Fixed shaft 180: Driven gear 190: One-way clutch 521: Rotating shaft 522: Roller 531: Rotating shaft 532: Auxiliary roller 541: Rotating shaft 542: Stirring member 551: Blade 552: Blade support means 553: Elastic biasing means

Claims (2)

[Claims] 1. A developing device having a photoconductor, a developer applying means for forming a toner image on the photoconductor, and a common driving means for rotating the photoconductor and the developer applying means of the developing device. A drive source, a first power transmission mechanism that transmits the power of the drive source to the photoconductor, and a second power transmission mechanism that transmits the power of the drive source to the developer applying unit of the developing device, A cleaning blade disposed so that the front edge portion is pressed against the surface of the photoconductor, and the drive source is reversed after the image forming operation is completed to reverse the photoconductor by a predetermined rotation angle in a direction opposite to the predetermined direction. An image forming machine to be driven, wherein a coupling having a predetermined play corresponding to the predetermined rotation angle is arranged in the second power transmission mechanism. 2. A rotation restricting means for restricting rotation in a direction opposite to a predetermined direction is provided in a power transmission mechanism for drivingly connecting the coupling and the developer applying means in the second power transmission mechanism. The image forming machine according to Item 1.