JPH08152831A - Photoreceptor cleaning device of image forming machine - Google Patents

Abstract

PURPOSE: To proivde a photoreceptor cleaning device for image forming machine capable of preventing toner from falling on a transfer paper carrying path even though a photoreceptor is turned by more than a specified amount at the time when the photoreceptor is reversely driven. CONSTITUTION: The photoreceptor cleaning device 7 of image forming machine provided with a photoreceptor 1, a cleaning balde 72 disposed in a state where the leading edge part of the blade 72 is brought into press-contact with the surface of the photoreceptor, a cleaning roller 74 disposed in contact with the surface of the photoreceptor on the upstream side from the cleaning blade, and a driving device for driving the photoreceptor and the cleaning roller is provided with a bias voltage impressing means 9 impressing a bias voltage, having the same polarity as that of an electrostatic latent image formed on the photoreceptor, on the cleaning roller, and a controlling means 306 operating and controlling the bias voltage impressing means and a driving device. The controlling means operates and controls the driving device in order to reversely drive the photoreceptor and the cleaning roller, and also operates and controls the bias voltage impressing means after finishing image forming operation by the image forming machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for a photoconductor mounted on an image forming machine such as an electrophotographic device or an electrostatic recording device, and more specifically, a photoconductor which moves with a residual developer attached thereto. A cleaning blade disposed by pressing the tip edge portion to the surface of the photosensitive member, and paper dust and the like adhering to the surface of the photosensitive member disposed in contact with the photosensitive member surface on the upstream side of the cleaning blade. The present invention relates to a photoconductor cleaning device for an image forming machine including a cleaning roller.

[0002]

2. Description of the Related Art As described above, in a cleaning device in which a cleaning roller is provided upstream of a cleaning blade, paper dust adhering to the surface of a photosensitive member is collected by the cleaning roller. However, it is impossible to completely collect the paper dust adhering to the surface of the photoconductor by the cleaning roller, and residual paper dust may move to the cleaning blade. When foreign matter such as residual paper dust or dust is caught between the surface of the photoconductor and the cleaning blade, the surface of the photoconductor is scraped in the circumferential direction by the foreign matter, resulting in vertical streaks in the image. appear. In particular, the photoconductor formed of an organic photoconductor is more likely to be scratched than the selenium photoconductor, and the above phenomenon appears prominently. Normally, even if the surface of the photoconductor is scraped by foreign matter that is caught between the surface of the photoconductor and the cleaning blade, if the foreign matter is removed, the area around the shaved surface will be surfaced by the photosharpening action of the cleaning blade. Are uniformed, there is no possibility of appearing as vertical stripes on the image. Further, since the cleaning blade made of a flexible material such as rubber is pressed against the surface of the photoconductor, the developer (toner) is always present at the contact portion between the cleaning blade and the surface of the photoconductor. This developer has a property of being cohesively fused by heat or pressure, and the cohesive toner adheres to the edge portion of the cleaning blade that comes into contact with the surface of the photoreceptor,
There is a problem in that the cleaning performance is deteriorated and black stripes appear in the axial direction of the photoconductor, which are so-called blade marks. In order to solve such problems,
A magnetic roller is arranged on the upstream side of the cleaning blade,
Japanese Patent Application Laid-Open No. 58-34477 discloses a technique in which the photoconductor is reversely controlled so that the contact portion of the photoconductor surface with the cleaning blade returns to the position of the magnetic roller after completion of copying.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
When the technique disclosed in Japanese Patent No. 477 is applied to a cleaning device in which a cleaning roller is arranged on the upstream side of a cleaning blade, when the photoconductor is driven in reverse,
It is desirable that the cleaning roller be driven in reverse at the same time. This is because if the cleaning roller is stopped when the photoconductor rotates in the reverse direction, a relative rotation difference occurs between the two, so that the contact portion of the photoconductor with the cleaning roller may be damaged. Further, when the toner scraped at the contact portion with the cleaning blade during the reverse driving of the photoconductor moves beyond the cleaning roller,
The transfer paper provided on the upstream side of the cleaning roller is scraped off by a separation claw for separating the transfer paper from the photoconductor. The scraped off toner falls on the transfer paper transport path and stains it, which causes dirt on the back surface of the transfer paper. In order to eliminate such a problem, drive control may be performed so that the portion which the cleaning blade was in contact with at the end of copying is stopped at the position of the cleaning roller during reverse drive. However, the distance (predetermined amount) from the cleaning blade to the cleaning roller is a minute amount. Therefore, in the case where the electric motor is used as the drive source of the driving device that drives the photoconductor, the rotation amount of a minute amount should be controlled. Is extremely difficult, and the variation in control becomes large, and there are cases where the amount exceeds a predetermined amount and in some cases, rotation does not occur. That is, the power supply to the electric motor at the time of reverse rotation is instantaneously for an extremely short time, and the photoconductor is rotated by the rotational force due to the inertial force. Therefore, the rotation amount of the photoconductor is controlled to the predetermined amount. It will be difficult. In order to eliminate such problems,
It is possible to separately provide a driving device for driving the photoreceptor in reverse, but there is a problem that the entire device becomes expensive.

Further, in general, the photosensitive member is configured to move in the axial direction and be detachably mounted so that the rotation shaft and the driving device are transmission-coupled. Therefore, in order to facilitate the connection between the rotary shaft of the photoconductor and the drive device, the rotary shaft and the drive device are connected by a coupling having play in the rotational direction. As described above, when the rotation shaft of the photoconductor and the drive device are transmission-coupled by the coupling having a play in the rotation direction, when the photoconductor is driven in the reverse direction after the copying is completed, only the play of the coupling is generated. Reverse rotation of the photoconductor is delayed.
On the other hand, the cleaning roller is generally configured to be drivingly connected to a driving device having a common driving source for driving the photoconductor. Therefore, when the driving source is reversely driven to reverse the photoconductor after completion of copying, It is rotated before the photoconductor. As a result, a large relative rotation difference temporarily occurs at the contact portion between the rotating cleaning roller and the stopped photosensitive member. For this reason, the contact portion of the photosensitive member with the cleaning roller may be damaged. In order to solve such a problem, it is conceivable to dispose an electromagnetic clutch in the drive device for the cleaning roller and control the connection of the electromagnetic clutch according to the play amount of the coupling. However, there is a problem that the entire device becomes expensive.

The present invention has been made in view of the above points, and a first technical problem is that the toner to the transfer paper conveying path is rotated even if the photoconductor rotates a predetermined amount or more when the photoconductor is rotated in the reverse direction. It is an object of the present invention to provide a photoconductor cleaning device for an image forming machine, which can prevent the toner from falling.

A second technical object of the present invention is to provide a photoconductor cleaning device for an image forming machine, which can inexpensively configure a cleaning device for achieving the first technical problem. It is in.

A third technical object of the present invention is to drive the photoconductor and the cleaning roller by a driving device having a common drive source, and to move the photoconductor in the axial direction by the above driving. Provided is a photoconductor cleaning device for an image forming machine, which is configured to be transmission-coupled to the device with a predetermined play in the circumferential direction and is capable of operating the photoconductor and the cleaning roller substantially simultaneously when the photoconductor is driven in reverse. Especially. Other technical problems and characteristics of the present invention will be clarified by the following description.

[0008]

According to a first aspect of the present invention, in order to achieve the above-mentioned first technical object, a photosensitive member and a tip edge portion are arranged in pressure contact with the surface of the photosensitive member. And a cleaning roller disposed in contact with the surface of the photoconductor on the upstream side of the cleaning blade, the photoconductor, and a driving device for driving the cleaning roller. In the cleaning device, bias voltage applying means for applying a bias voltage having the same polarity as the polarity of the electrostatic latent image formed on the photoconductor to the cleaning roller, and control for controlling the operation of the bias voltage applying means and the driving device. And means,
After the completion of the image forming operation of the image forming machine, the control means controls the operation of the drive device so as to reversely drive the photoconductor and the cleaning roller, and also controls the operation of the bias voltage applying means. A photoreceptor cleaning device for an image forming machine is provided.

According to a second aspect of the present invention, in order to achieve the above-mentioned second technical object, a photoconductor and a developing device equipped with a developer applying means for forming a toner image on the photoconductor. ,
A cleaning blade disposed by pressing the tip edge portion onto the surface of the photosensitive member, a cleaning roller disposed in contact with the surface of the photosensitive member on the upstream side of the cleaning blade, the photosensitive member and the cleaning roller In the photoconductor cleaning device of the image forming machine having a driving device for driving the electrostatic latent image formed on the photoconductor, the developer applying means of the developing device and the cleaning roller have the same polarity as that of the electrostatic latent image formed on the photoconductor. A bias voltage applying unit having a common power source for applying a bias voltage, and a control unit for controlling the operation of the bias voltage applying unit and the driving device are provided, and the control unit is provided after the image forming operation of the image forming machine is completed. Controlling the drive device so as to drive the photosensitive member and the cleaning roller in the reverse direction, and also controlling the operation of the bias voltage applying means. To, photoconductor cleaning device of the image forming apparatus is provided, characterized in that.

Further, in order to achieve the above-mentioned third technical object, according to the third aspect of the present invention, a photosensitive member and a cleaning blade disposed so that the front edge portion is pressed against the surface of the photosensitive member. And a cleaning roller disposed in contact with the surface of the photoconductor on the upstream side of the cleaning blade,
In a photoconductor cleaning device of an image forming machine, which comprises a photoconductor and a drive device having a common drive source that is transmission-coupled to the cleaning roller, the photoconductor cleaning device is rotated by axially moving the photoconductor. A first coupling for transmitting and connecting in a predetermined direction with a predetermined play, and a second coupling for transmitting and connecting the rotation shaft of the cleaning roller and the driving device in a predetermined direction with a predetermined play. A photoconductor cleaning device for an image forming machine is provided.

[0011]

In the photoconductor cleaning device of the image forming machine according to the present invention, after the control means finishes the image forming operation of the image forming machine, the driving device is operated to drive the photoconductor and the cleaning roller in the reverse direction, and the bias voltage is applied. By controlling the operation of the means, a bias voltage having the same polarity as that of the electrostatic latent image is applied to the cleaning roller. Therefore, a bias voltage having the same polarity as that of the electrostatic latent image is applied to the cleaning roller, so that the electrostatic attraction force generated on the cleaning roller causes the cleaning roller to scrape off the toner onto the surface of the photoconductor. Toner and foreign matter are effectively collected.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the accompanying drawings showing a preferred embodiment of the photoconductor cleaning device for an image forming machine constructed according to the present invention.

FIG. 1 is a schematic structural view showing an embodiment of an image forming machine equipped with a photoconductor cleaning device according to the present invention, and a driving device for driving a photoconductor, a developing device and a cleaning device of the image forming machine shown in FIG. FIG. 3 is a perspective view of a coupling for drivingly connecting the rotary shaft of the photoconductor to the driving device, and FIG. 4 is a cup for drivingly connecting the rotary shaft of the cleaning roller equipped in the cleaning device to the driving device. It is a perspective view of a ring.

The image forming machine shown in FIG. 1 includes a photosensitive member 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. As shown in FIG. 2, a hole 211 is formed in the center of the rotary shaft 21 of the rotary drum 22, and engaging projections 212, 212 forming a coupling 210 are provided on the end face thereof. There is. The engaging protrusions 212, 212 are provided with a phase angle of 180 °. A coupling member 213 that forms the coupling 210 with the engaging portions 212, 212 is fixed to a rotary shaft 101 that is mounted on a unit housing (not shown) and transmission-coupled to a drive device 10 described later. Engaging projections 214, 214 formed with a phase angle of 180 ° are provided on the end surface of the connecting member 213. The rotary shaft 101 has a guide connecting portion 102 that projects toward the engaging projections 214, 214 and has a truncated cone-shaped tip.
It has. Therefore, when the photoconductor 2 is mounted in a unit housing (not shown), if the photoconductor 2 is moved axially toward the rotary shaft 101, first, the rotary shaft 21 of the photoconductor 2 is moved.
When the guide connecting portion 102 is inserted into the hole 211 formed in the hole and further moved, the engaging protrusions 212, 212 and the engaging protrusions 214, 214 forming the coupling 210 are in a rotationally coupled state for transmission. . The engagement protrusion 21
2, 212 and the engaging protrusions 214, 214 are each 180 °
Since they are provided with a phase angle of, the probability that they will face each other at the time of connection is low, and even if they are facing each other, the photoconductor 2 can be easily mounted by slightly rotating one of them. . Therefore, the coupling 210 configured as described above is transmission-coupled with a predetermined play in the rotation direction.

Around the photosensitive member 2 having the above-mentioned structure, the charging corona discharger 3, the exposing means 4, the developing device 5, and the transfer corona discharge are sequentially seen in the rotation direction indicated by the arrow A. An electric appliance 6, a cleaning device 7 constructed according to the invention, and a static elimination lamp 8 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 (+), and the photosensitive layer 2 of the photoconductor 2
It is set according to the type of the photoconductive material forming No. 3.

The developing device 5 includes a developer applying means 52 which is mounted in the developing housing 51 and is arranged so as to face the photoconductor 2. This developer applying means 52
Is composed of a cylindrical sleeve member 522 which is rotationally driven in the direction of arrow D, and a stationary permanent magnet 523 which is arranged in the sleeve member 522. In the illustrated embodiment, the sleeve member 522 is connected to the (+) pole of the power source E via the first drive circuit D1 that constitutes the bias voltage applying means 9, and is (+) pole during image formation. )
The voltage can be applied. Further, in the illustrated embodiment, the transfer corona discharger 6 is applied with electric power of (+) polarity during image formation. In the developing housing 51, a developer stirring and conveying member 53 is arranged in parallel with the developer applying means 52. The developer stirring / conveying member 53 supplies the developer to the developer applying means 52 while stirring the developer in the developing housing 51.

Next, the cleaning device 7 will be described. The cleaning device 7 includes a cleaning blade 72, which is arranged by pressing the leading edge portion against the outer peripheral surface of the photoconductor 2.
Is provided. The cleaning blade 72 is made of an elastic material such as rubber, and is attached to a blade holder 73 attached to the cleaning housing 71. On the upstream side of the cleaning blade 72, a cleaning roller 74 for collecting paper dust and dust attached to the outer peripheral surface of the photoconductor 2 is arranged. The cleaning roller 74 includes a rotating shaft 7 made of metal such as steel.
41 and a sponge-like roller portion 742 mounted on the outer peripheral surface of the rotating shaft 741 with a conductive adhesive. The outer peripheral surface of the roller portion 742 contacts the outer peripheral surface of the photoconductor 2. It is arranged in the state. Roller part 742
Is formed by impregnating a roll member formed of foam such as urethane foam or silicon foam with a conductive substance such as carbon, and has a volume electric resistance value of 10 ⁶ to
It is set to 10 ¹⁴ Ωcm. In addition, the roller portion 7
As a method of impregnating the conductive material into the roll member constituting 42, for example, a roll member formed of a foam such as urethane foam or silicon foam is dipped in a solution in which a powder of a conductive material such as carbon is dissolved, It is possible to use a method of impregnating the roll member with a solution of powder of a conductive substance and then drying. The rotating shaft 741 of the cleaning roller 74 thus configured is connected to the (+) pole of the power source E via the second drive circuit D2 that constitutes the bias voltage applying means 9 in the illustrated embodiment. . As shown in FIG. 3, an engaging pin 701 that constitutes the coupling 700 is provided at the end of the rotary shaft 741. A roller driving gear 702 that constitutes the engagement pin 701 and the coupling 700 is provided with a hole 703 in which the rotary shaft 741 is fitted, at the center, and
An engagement cutout hole 704 is formed continuously with the hole 703 and has a radial length corresponding to the engagement pin 701. The engagement notch hole 704 is formed at a predetermined angle in the circumferential direction corresponding to the play in the rotational direction of the coupling 210. Therefore, the roller drive gear 70
The rotation shaft 741 of the cleaning roller 74 in the second hole 703.
And the engaging pin 701 mounted on the rotating shaft 741 is fitted into the engaging cutout hole 704 of the roller drive gear 702, the coupling 700 can be configured. When the roller drive gear 702 is assembled to the rotary shaft 741 as described above, the roller drive gear 7
By mounting a known retaining means such as a snap ring on both sides of 02, the axial movement of the roller drive gear 702 on the rotating shaft 741 is restricted. The roller driving gear 702 of the coupling 700 configured as described above
When the cleaning device 7 is mounted on a unit housing (not shown), by moving toward the intermediate gear 103 fixed to the rotary shaft 102 mounted on the unit housing and transmission-coupled to the drive device 10 described later, It is adapted to mesh with the intermediate gear 103. Inside the cleaning housing 71, there is provided a scraping plate 75 which scrapes off the toner adhering to the cleaning roller 74 in contact with the outer peripheral surface of the cleaning roller 74, and the toner scraped by the scraping plate 75. Carrying screw 76 for carrying the toner to a toner collecting container (not shown)
Is provided. In addition, the cleaning roller 74
On the upstream side of the lower blade 76 and the transfer paper separating claw 77.
Are provided, and these are attached to the cleaning housing 71 via an appropriate attachment member.

Next, the photoconductor 2 and the developer applying means 5
2, developer stirring and conveying member 53, cleaning roller 74
And drive device 10 for rotationally driving the conveying screw 76
Will be described with reference to FIG. The drive device 10 is
In the illustrated embodiment, an electric motor M, which is a common drive source, is provided. Rotational drive shaft 105 of the electric motor M
A small diameter toothed pulley 106 and a large diameter toothed pulley 107 are mounted on the. A rotary shaft 10 that is transmission-coupled to the rotary shaft 21 of the photoconductor 2 by a coupling 210.
1, a large diameter drum drive toothed pulley 108 and a transmission gear 109 are attached to the drum drive toothed pulley 108 and the rotary drive shaft 105 of the electric motor M. A timing belt 110 is wound around the toothed pulley 106. Therefore, when the electric motor M rotates in the direction of arrow B, the toothed pulley 106, the timing belt 110, and the drum drive toothed pulley 10
The photoconductor 2 is rotationally driven in the direction of arrow A via 8. A toothed pulley 111 and a transmission gear 112 are mounted on a rotary shaft 531 of the developer stirring / conveying member 53 constituting the developing device 5, and the toothed pulley 111 and the rotary drive shaft 105 of the electric motor M are mounted on the rotary shaft 531. The timing belt 113 is wound around the toothed pulley 107. Further, a sleeve drive gear 114 is mounted on the rotary shaft 521 of the sleeve member 522 which constitutes the developer applying means 52, and the sleeve drive gear 114 is attached to the transmission gear 112.
Is configured to mesh with. Therefore, when the electric motor M rotates in the arrow B direction, the developer agitating / conveying member 53 is rotationally driven in the arrow C direction via the toothed pulley 107, the timing belt 113, and the toothed pulley 111.
Further, the sleeve member 522 is rotationally driven in the direction of arrow D via the transmission gear 112 mounted on the rotating shaft 631 having the toothed pulley 111 mounted thereon, and the sleeve drive gear 114 meshing with the transmission gear 112. On the other hand, the cleaning roller 7 constituting the cleaning device 7
The intermediate gear 103 meshing with the roller drive gear 702 mounted on the rotating shaft 741 of No. 4 meshes with the transmission gear 115 meshing with the transmission gear 109. Further, a screw drive gear 116 is mounted on the rotary shaft 761 of the conveying screw 76, and the screw drive gear 116 is mounted on the rotary shaft 761.
Reference numeral 6 is in mesh with the roller drive gear 702. Therefore, when the electric motor M rotates in the direction of arrow B and the photoconductor 2 is rotationally driven in the direction of arrow A as described above, the photoconductor 2 is rotated.
The cleaning roller 74 is rotationally driven in the direction of arrow F via the transmission gear 109, the transmission gear 115, the intermediate gear 103, and the roller drive gear 702 mounted on the rotating shaft 101 of FIG. Further, the conveying screw 76 is rotationally driven in the arrow G direction via the screw driving gear 116 meshing with the roller driving gear 702.

The photoconductor cleaning device of the image forming machine is equipped with the control means 300 shown in FIG. The control unit 300 is configured by a microcomputer, and has a central processing unit (CPU) 301 that performs arithmetic processing according to a control program, a read-only memory (ROM) 302 that stores the control program, and a readable / writable storage that stores the arithmetic result and the like. Random access memory (RAM)
303, timer 304, and input / output interface 3
05, and controls the operation of the electric motor M and the first drive circuit D1 and the second drive circuit D2.

The photoconductor cleaning device of the image forming machine according to the present invention is constructed as described above, and its operation will be described below. At the time of image formation, the charging corona discharger 3, the exposure unit 4, the transfer corona discharger 6, and the charge eliminating lamp 8 are operated, and the electric motor M of the drive device 10 rotates in the forward direction indicated by the arrow B. Driven. When the electric motor M is driven to rotate in the direction of the arrow B, the photosensitive member 2, the developer stirring / conveying member 53 and the sleeve member 522 that form the developing device 5, and the cleaning roller that forms the cleaning device 7 are processed as described above. 74
And the conveying screw 76 is rotationally driven in the directions indicated by the arrows. A bias voltage of (+) polarity is applied to the sleeve member 522 of the developing device 5 via the drive circuit D1. Therefore, the sleeve member 5
Since the outer peripheral surface of 22 is charged with a (+) polarity electric charge, the drive housing 5 is charged with a (-) polarity.
The toner inside 1 is electrostatically attracted, and the function of attracting the carrier by the magnetic force of the stationary permanent magnet 523 improves the developer holding function of the sleeve member 522. Thus, while the photoconductor 2 is rotationally driven in the direction of arrow A, the photosensitive layer 23 of the photoconductor 2 is substantially uniformly charged to the specific polarity (+) by the charging corona discharger 3, and then the exposure is performed. An electrostatic latent image is formed on the photosensitive layer 23 by the means 4. Thereafter, the electrostatic latent image on the photosensitive layer 23 is developed into a toner image by the developer applying unit 52 of the developing device 5. 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 sheet on which the toner image is transferred and electrostatically attracted to the photosensitive member 2 to move is separated by the transfer sheet separating claw 77, and then fixed by a fixing unit (not shown),
It is ejected from the ejection roller. Further, when passing through the cleaning roller 74 of the cleaning device 7, 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 72 scrapes off the residual toner adhering to the outer peripheral surface of the photosensitive layer 23. The scraped toner adheres to the cleaning roller 74, rotates, is scraped by the scraping plate 75, and is then carried to the toner collecting container (not shown) by the carrying screw 76. In this way, the photoconductor 2 that has passed through the cleaning device 7 is
Further, the charge removal lamp 8 irradiates the photosensitive layer 23 with charge removal light to remove the charge.

The above is the image forming operation, and the operation immediately after the end of the image forming operation will be described with reference to the flowchart shown in FIG. The control means 300 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. Alternatively, it may be set when a signal from the discharge switch is confirmed after a predetermined number of sheets (for example, 200 sheets) have been transferred. After confirming the end of the image forming operation in this way, the control means 300 stops the electric motor M of the drive device 10 in step 2, and
The first driving circuit D1 is turned off to turn off the sleeve member 52.
The application of the bias voltage to 2 is cut off. Then, the control means 300 sets the timer (T) 304 to T1.
The set time T1 is set in consideration of the time during which each member constituting the drive device 10 operates due to inertia even when the electric motor M is stopped. In the illustrated embodiment, the set time T1 is set to 1.0 sec, for example. Has been done. Next, the control unit 300 causes the elapsed time TS after the electric motor M is stopped.
Checks whether or not the set time T1 has been reached (step S3). Then, the control means 300 waits if the elapsed time TS has not reached the set time T1, and if the elapsed time TS has reached the set time T1, proceeds to step S4 to reversely drive the electric motor M. At the same time, the second drive circuit D2 is turned on to apply a bias voltage of (+) polarity to the cleaning roller 74. Then, the control means 300 sets the timer (T) 304 to T2. The set time T2 is the time required for the position of the cleaning blade 72 of the photosensitive member 2 in contact with the cleaning roller 74 to reach the cleaning roller 74 when the image forming operation is finished and the photosensitive member 2 is stopped. In this embodiment, for example, it is set to 50 msec. As described above, by rotating the electric motor M in the reverse direction, the photoconductor 2 is rotationally driven in the direction opposite to the arrow A and the cleaning roller 74 is rotationally driven in the direction opposite to the arrow F. Therefore, when foreign matter such as paper dust or dust is caught between the surface of the photosensitive layer 23 of the photoconductor 2 and the cleaning blade 72, these foreign matter are carried to the cleaning roller 74 and collected. Since the cleaning roller 74 is applied with the bias voltage of (+) polarity as described above, it is attached to the surface of the photosensitive layer 23 while being scraped off by the cleaning blade 72 by its electrostatic attraction force. It is possible to effectively collect the remaining toner and the above-mentioned foreign matter. Therefore, even if the photoconductor 2 overruns, the toner adhering to the surface of the photosensitive layer 23 in a state of being scraped off by the cleaning blade 72 does not pass through the cleaning roller 74 and fall out of the cleaning device. Since the cleaning roller 74 is also driven in the reverse direction when the photoconductor 2 rotates in the reverse direction, a large relative speed difference does not occur between the two, so that the photosensitive layer 22 of the photoconductor 2 is not formed.
Will not damage. In addition, the cleaning roller 74
The coupling 700 that power-connects the rotating shaft 741 of the photosensitive member 2 and the driving device 10 is formed by:
Since the play in the rotation direction corresponding to the play in the rotation direction of the coupling 210 for transmitting and connecting the and is formed, the operation of the cleaning roller 74 precedes at the beginning of the reverse drive and a large relative speed difference is generated between the two. There is nothing to do.
As described above, when the electric motor M is reversely driven and the bias voltage of the (+) polarity is applied to the cleaning roller 74, the control means 300 proceeds to step S5 to reversely drive the electric motor M. It is checked whether the time TS has reached the set time T2. Then, the control means 300 waits if the elapsed time TS has not reached the set time T2, and if the elapsed time TS has reached the set time T2, proceeds to step S6 and stops the electric motor M. , The second drive circuit D2 is turned off to stop the application of the bias voltage to the cleaning roller 74.

[Experimental Example] Volume electric resistance value is 10 ¹² Ωcm
The cleaning roller 74 having the roller portion 742 is manufactured, and various bias voltages are applied to the cleaning roller 74 at the time of the reverse driving, so that the photosensitive layer 23 of the photoconductor 2 can be obtained.
I visually checked the condition of the surface. As a result, when the bias voltage was (−) 100V to (−) 300V, a considerable amount of toner adhered to the surface of the photosensitive layer 23. On the other hand, when the bias voltage was (+) 100V to (+) 200V, a small amount of toner adhered to the surface of the photosensitive layer 23.
The bias voltage is (+) 300V to (+) 500.
It was found that when V was set, almost no toner adhered to the surface of the photosensitive layer 22. Therefore, the volume electric resistance value is 10
^When a cleaning roller of about ¹² Ωcm is used and the polarity of the electrostatic latent image is (+), a bias voltage of (+) 300V or more may be applied to the cleaning roller 74.

[0023]

The photoconductor cleaning device of the image forming machine according to the first aspect of the present invention is configured as described above, and the bias voltage having the same polarity as the polarity of the electrostatic latent image formed on the photoconductor is applied to the cleaning roller. A bias voltage applying unit and a control unit for controlling the operation of the bias voltage applying unit and the driving unit for driving the photosensitive member and the cleaning roller are provided. After the control unit finishes the image forming operation of the image forming machine, the photosensitive member and the cleaning unit are cleaned. Since the drive device is controlled so as to drive the roller in the reverse direction and the bias voltage applying means is controlled so that the bias voltage having the same polarity as the electrostatic latent image is applied to the cleaning roller, Electric attraction force is generated. Therefore, it is possible to effectively collect the toner and the foreign matter adhering to the surface of the photoconductor while being scraped off by the cleaning blade by the electrostatic attraction force. For this reason, even if the photoconductor overruns during reverse rotation, the toner adhering to the photoconductor surface while being scraped off by the cleaning blade does not pass through the cleaning roller and fall out of the cleaning device. In addition, since the cleaning roller is also driven in reverse when the photoconductor rotates in the reverse direction, a large relative speed difference does not occur between the two, so that the surface of the photoconductor is not damaged.

In the photoconductor cleaning device of the image forming machine according to the second invention, the bias voltage applying means for applying the bias voltage to the cleaning roller is the bias voltage applying means for applying the bias voltage to the developer applying means of the developing device. Since the cleaning roller is configured to be commonly used, it is not necessary to separately equip the cleaning roller with bias voltage applying means for applying a bias voltage, and the entire apparatus can be inexpensively configured.

In the photoconductor cleaning device of the image forming machine according to the third aspect of the present invention, the second coupling for drivingly connecting the rotating shaft of the cleaning roller and the driving device to the driving device is drivingly connecting the rotating shaft of the photosensitive member. Since the play in the circumferential direction corresponding to the play in the rotation direction of the first coupling is configured, the operation of the cleaning roller precedes the operation in the state where the photoconductor is stopped at the beginning of the reverse drive. Can be prevented. Therefore, it is possible to prevent damage to the surface of the photoconductor due to the large relative speed difference between the photoconductor and the cleaning roller.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a coupling that power-connects a rotation shaft of the photoconductor shown in FIG. 1 and a driving device.

FIG. 3 is a perspective view of a coupling that power-connects a rotation shaft of a cleaning roller and a driving device that constitute the cleaning device shown in FIG.

FIG. 4 is a schematic configuration diagram of a driving device that drives the photoconductor, the cleaning device, and the developing device shown in FIG.

5 is a flowchart showing an example of the operation of the control means 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: Cleaning device 8: Elimination lamp 9: Bias voltage applying device 10: Driving device 21: Rotation of photoconductor Axis 22: Rotating drum 23: Photosensitive layer 51: Developing housing 52: Developer applying means 53: Developer stirring and conveying member 71: Cleaning housing 72: Cleaning blade 73: Blade holder 74: Cleaning roller 74 75: Scraping plate 76: Conveying screw 77: Transfer paper separating claw 103: Intermediate gear 105: Electric motor rotation drive shaft 106: Toothed pulley 107: Toothed pulley 108: Drum drive toothed pulley 109: Transmission gear 110: Timing belt 111: Toothed pulley 112 : Transmission gear 113: Timing belt 114: Sleeve drive gear 15: Transmission gear 116: Screw drive gear 210: Coupling 211: Hole 212: Engagement part 213: Connection member 214: Engagement part 300: Control means 301: Central processing unit (CPU) 302: Read only memory (ROM) 303: Random access memory (RAM) 304: Timer 305: Input / output interface 522: Sleeve member 523: Static permanent magnet 700: Coupling 701: Engagement pin 702: Roller drive gear 703: Hole 704: Engagement notched hole 741: Rotating shaft of cleaning roller 742: Roller part D1: First drive circuit D2: Second drive circuit E: Power supply M: Electric motor

Claims (3)

[Claims] 1. A photosensitive member, a cleaning blade disposed so that a front edge portion is pressed against the surface of the photosensitive member, and a cleaning roller disposed in contact with the surface of the photosensitive member on the upstream side of the cleaning blade. And a biasing device having the same polarity as the polarity of the electrostatic latent image formed on the photoconductor on the cleaning roller. A bias voltage applying means for applying a voltage and a control means for controlling the operation of the bias voltage applying means and the driving device are provided, and the control means includes the photosensitive member and the photosensitive member after the image forming operation of the image forming machine is completed. An image, characterized in that the drive device is operated and controlled so as to reversely drive the cleaning roller, and the bias voltage applying means is also operated and controlled. Photoconductor cleaning device for forming machine. 2. A photosensitive member, a developing device having a developer applying means for forming a toner image on the photosensitive member, and a cleaning blade disposed so that the front edge portion is in pressure contact with the surface of the photosensitive member. In a photoconductor cleaning device of an image forming machine, which comprises a cleaning roller disposed on the upstream side of the cleaning blade in contact with the surface of the photoconductor, and a drive device for driving the photoconductor and the cleaning roller, Bias voltage applying means having a common power source for applying a bias voltage having the same polarity as the polarity of the electrostatic latent image formed on the photoconductor to the developer applying means and the cleaning roller of the apparatus, and the bias voltage applying means. And a control unit that controls the operation of the drive unit, the control unit including the photosensitive member and the cleaning unit after the image forming operation of the image forming machine is completed. With operating controls the driving device so as to reversely rotate the over La, operating controls the bias voltage applying means, a photoreceptor cleaning device of an image forming machine, characterized in that. 3. A photosensitive member, a cleaning blade disposed so that the front edge portion is in pressure contact with the surface of the photosensitive member, and a cleaning roller disposed in contact with the surface of the photosensitive member on the upstream side of the cleaning blade. And a drive device having a common drive source that is transmission-coupled to the photoconductor and the cleaning roller, in a photoconductor cleaning device of an image forming machine, wherein the drive device is provided by moving the photoconductor in the axial direction. And a second coupling for transmitting and connecting the cleaning roller and the drive device with a predetermined play in the rotation direction. A photoconductor cleaning device for an image forming machine, characterized in that: