JPH0323468A - Cleaning device - Google Patents

Abstract

PURPOSE:To prevent a picture from deteriorating by consecutively driving a cleaning means for a prescribed time while a bias voltages is impressed thereon after the cleaning means is released from contact with a photosensitive body and driving the cleaning means while the bias voltage is impressed thereon a prescribed time before it is brought into the contact with the photosensitive body. CONSTITUTION:Such a control means 127 is provided that a conductive brush 124 is consecutively driven for the prescribed time while the bias voltage is impressed thereon after the cleaning means 119 is released from the contact with the photosensitive body 101 and that the conductive brush 124 is driven while the bias voltage is impressed thereon the prescribed time before the cleansing means 119 is brought into the contact with the photosensitive body 101. Thus, it is prevented that cleaning marks are generated on the photosensitive body 101 with a developer held by the brush 124 when the brush 124 is released from the contact with the photosensitive body 101 aftercleaning. It is also prevented that the inside scattering of the developer occures when the brush 124 is brought into the contact with the photosensitive body again for the cleaning process. Thus, the picture is prevented from deteriorating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device for a color copying machine. More specifically, the present invention relates to a cleaning device that cleans developer remaining on a photoreceptor or intermediate transfer member that forms a color image by sequentially overlapping images based on each copying process.

[Conventional technology]

As one of the color copying systems, black, yellow, magenta, etc. are printed near the photoreceptor. Equipped with a developing device each storing a cyan developer, an optical system consisting of lenses, mirrors, etc. irradiates information light corresponding to the content of the original onto a charged photoreceptor, and the photoreceptor is exposed to light. After an electrostatic latent image is formed on the electrostatic latent image and a first color development process is performed on the electrostatic latent image, the first color is transferred onto the photoconductor without performing the transfer process or the cleaning process on the photoconductor. The electrostatic latent image of the color is retained, and then a second color is applied as needed in the same process.
A color image is created on the photoreceptor by superimposing the electrostatic latent images that have been developed for the third and fourth colors.
There is a method of realizing color copying processing by transferring the images all at once onto transfer paper that is then conveyed.

Furthermore, there are color copying systems that utilize an intermediate transfer member instead of a photoreceptor. That is, this transfers the electrostatic latent image on the photoreceptor that has been developed using developer of each color.
It is equipped with an intermediate transfer body for holding. In the copying process in this type of color copying system, an optical system consisting of lenses, mirrors, etc. irradiates a charged photoconductor with information light corresponding to the content of the document, and performs an exposure process to place the photoconductor on the photoconductor. An electrostatic latent image is formed on the electrostatic latent image.
A first color development process is performed. Thereafter, the developed image is transferred to an intermediate transfer member, and the intermediate transfer member retains the first color image. Then apply a second color if necessary. The charging and n-light 1 development processes for the third and fourth colors are performed, and the color images are superimposed one after another on the intermediate transfer body, and finally, the superimposed color images are transferred all at once onto the transferred transfer paper. This is a method that realizes color copying processing by transferring the image.

Regarding the above two color copying systems. The photoconductor in the first example or the intermediate transfer body in the second example is used until the transfer process for each color to form a color is completed. The developed images retained on their surfaces must not be cleaned, for example by brush cleaning methods. It is necessary to release the brush from contact with the photoreceptor or intermediate transfer member.

Thereafter, the brush of the cleaning device that has been out of contact with the photoreceptor or intermediate transfer member is brought back into contact with the photoreceptor or intermediate transfer member, thereby cleaning the residual developer on the photoreceptor or intermediate transfer member.

The brush cleaning device described above uses a rotating cylindrical brush made of natural or hewei fiber bristles to contact the photoreceptor or intermediate transfer member. This method uses a brush to brush off the developer remaining on the surface. The developer thus brushed off is collected by the developer transport screw into the developer collection section.

The brush is electrically conductive and comes into contact with a metal roller to which a bias voltage is applied, and while cleaning the surface of the photoreceptor or intermediate transfer body is being performed, a bias voltage is applied to the brush and the developer is removed. Electrical suction prevents the developer from scattering as the brush rotates.

[Problem to be solved by the invention]

However, in conventional cleaning devices, in order to control the color image, when the brush is brought into a non-contact state with the surface of the photoreceptor or intermediate transfer body after the cleaning process, it is necessary to apply a bias voltage to the brush. ．． When the drive is stopped, the developer attached to the brush adheres to the photoconductor or intermediate transfer body, and the image based on the next copying process deteriorates due to the influence of the adhered developer, causing image defects. becomes. In addition, when the brush is brought back into contact after a series of color copying processes are completed, the brush may collide with the photoreceptor or intermediate transfer member. The residual developer on the photoconductor or intermediate transfer body that is to be cleaned this time is scattered. Not only does it stain the inside of the copier. There is also a risk that the scattered developer may get mixed into a plurality of developing devices of different colors, which may cause image deterioration.

The present invention has been made in view of the above points, and when the brush after cleaning is placed in a non-contact state with the photoreceptor or intermediate transfer member, the developer held by the brush is used to develop the image on the photoreceptor or intermediate transfer member. This prevents image deterioration by avoiding cleaning marks caused by cleaning agents, and also prevents internal scattering of developer that occurs when the brush is brought into contact with the photoconductor or intermediate transfer body again for cleaning processing. The purpose of this invention is to prevent image deterioration due to contamination of the inside of the copying machine by the developer or contamination of the developer into the developing device.

[Means for Solving the Problems] The present invention achieves the above objects. Even after the cleaning means maintains a non-contact state with respect to the photoreceptor or intermediate transfer member, the conductive brush of the cleaning means is continuously driven for a predetermined period of time with a bias voltage applied thereto. Further, the cleaning means has a control means for driving the conductive brush of the cleaning means with a bias voltage applied thereto for a predetermined time before the cleaning means prevents the contact state from being brought into contact with the photoreceptor or the intermediate transfer member in order to execute the cleaning state. A cleaning device is provided.

[Effect]

The cleaning device according to the present invention continues to drive the conductive brush of the cleaning means with a bias voltage applied for a predetermined period of time even after the cleaning means is in a non-contact state with respect to the photoreceptor or the intermediate transfer member, and The conductive brush of the cleaning means is driven with a bias voltage applied thereto for a predetermined period of time before the cleaning means comes into contact with the photoreceptor or intermediate transfer member. [Embodiment] Hereinafter, an embodiment of a cleaning device according to the present invention will be described based on the accompanying drawings.

Figure 1 is an example of a color copying system that utilizes the present invention. A photosensitive drum 101 that receives information light from an optical system (not shown) and exposes an electrostatic latent image on its surface.
A charger 126 is installed near the photoreceptor drum 101 and performs a charging process on the surface of the photoreceptor drum 101. a developing device 103 that performs a developing process on the electrostatic latent image; static eliminators 112 and 125 that release the charged state of the photoreceptor drum 101; and a static eliminator 1.
17, a cleaning device 119 for removing residual developer on the surface of the photoreceptor drum 101, and a cleaning device 119 for removing residual developer on the surface of the photoreceptor drum 101;
01 onto a transfer plate 113 conveyed by a registration roller 114.

The developing device 103 includes a Y developing device 105 having a Y developing roller 104 that develops the electrostatic latent image formed on the photoreceptor drum 101 with a first color developer (yellow: Y).
, an M developing device 107 having an M developing roller 106 for developing with a second color developer (magenta 2M), and a C developing roller 10B for developing with a third color developer (cyan: C). C developing device 109 and . B3 developing roller 111 that develops with a fourth color developer (black: Bk)
The B1 developing unit 110 has a B1 developing unit 110.

Developing rollers l04, 106, 108 installed inside each of the above developing devices 105, 107, 109, 110
, 111 performs development processing without contacting the photoreceptor drum 101. In addition, the cleaning device 119. A conductive brush 124 for brushing off residual developer on the photoreceptor drum 101 after the transfer process is completed. a bias roller 123 connected to a bias power supply 122 and applying a bias voltage to the conductive brush 124; and a bias roller 123.
The bias blade 121 that cleans the conductive brush 124, the developer transport screw 118 that transports the developer brushed off by the conductive brush 124 to a predetermined developer collection section (not shown), and the cleaning device 119. A sealing member 16 made of urethane rubber or the like, for example, prevents overflow of the agent.

Further, the cleaning device 119 is connected to the photoreceptor drum 10.
1, a drive circuit 130 for driving the solenoid 120, and the solenoid 120 or the static eliminator 117.
Detects the operation of the HIAS electrician a12 2. It includes a control section 127 that outputs control signals to the conductive brush 124 and the like. The control section 127. An input interface (not shown) that digitizes the detection signal and inputs it to the bus line (not shown).
(not shown), an output interface (not shown) that outputs control signals etc. in a predetermined format, a ROM (not shown) that stores programs for performing various control processes, and a ROM (not shown) that stores programs for performing various control processes. A CPU (not shown) that executes various processes according to stored programs;
A RAM (not shown) for storing processing results and data is also included.

The operation of the above structure will be explained using the timing chart of FIG.

As shown in the timing chart of FIG. 2, when a copy start command signal is manually input to the control unit 127,
27 processes the copy start command signal internally, and charges the charger 1.
26, the charger 126 is turned on (point A in FIG. 2), and as a result, the photosensitive drum 101 is uniformly charged.

Thereafter, exposure processing for the first color is started for the photosensitive drum 101 using the information light 102 from the exposure optical system (
Figure 2 point B). While the first color exposure process is being executed, the static eliminator 117 for the photosensitive drum 101 is turned OFF.
(Point C in Figure 2), the static elimination process is stopped, and the control section 127 outputs a control signal to the drive circuit 130,
The solenoid 120 is driven to move the cleaning device 119 in the opposite direction to the photoconductor drum 101, and the conductive brush 124 of the cleaning device 119 is moved toward the photoconductor drum 1.
01 (point D in Figure 2). however,
Bias electric if! The application of bias voltage to the bias roller 123 from I22 is performed by the cleaning device 119.
This continues for a period of time 1 from the time when the conductive brush 124 comes out of contact with the photoreceptor drum 101 (point D in FIG. 2) to point E in FIG. At the same time, the rotation of the conductive brush 124 of the cleaning device 119 continues for only the time t1 from point D in FIG. 2 to point E in FIG. 2.

As a result, by driving the conductive brush 124 to which a bias voltage is applied, not only the residual developer on the surface of the photoreceptor drum 101 is completely absorbed, but also the developer attached to the conductive brush 124 is electrically removed. Even after the conductive brush 124 comes out of contact with the photoreceptor drum 101, it is sent out in the direction of the developer transport screw 11B to remove all the developer attached to the conductive brush 124.

As above. After the application of the bias voltage and the rotation of the conductive brush 124 are stopped at point E in Figure 2, the exposure process for the first color is completed (point F in Figure 2), and the electrostatic latent image formed is The Y developing roller 104 of the developing device 105 executes development processing using yellow developer, and the photosensitive drum 101
The developed image formed on the photoreceptor drum 101 is held as it is, and the static elimination lamp 112 and transfer device 115 are in an OFF state.
, a static eliminator 117, and a cleaning device and static eliminator lamp 125 that are in a non-contact state with respect to the photoreceptor drum 101.
, and the charger 126 in the ON state charges 2
The second charging process is performed.

after that. Exposure processing for the second color is started (point G in Figure 2)
, continues until point H in Figure 2. The M developing device 10 is superimposed on the yellow image already formed on the photosensitive drum 101.
The M developing roller 106 of No. 7 executes development processing using magenta developer, the image is held as it is, and the image passes through a cleaning device etc. which is in the OFF state in the same manner as above, and a third charging process is executed by the charger 126. Ru. Thereafter, the exposure process for the third color is executed (point 1 in FIG. 2), and the exposure process ends at point J in FIG. The electrostatic latent image formed by the C developing roller 108 of the C developing device 109 is developed using a cyan developer.

Similarly, a fourth color exposure process is performed on the photosensitive drum 101 (point K in FIG. 2). During this time, the control unit 127 outputs a control signal to the registration roller 114 to turn on the registration roller 114 (point L in Figure 2), and transfers the transfer plate 113 from the paper feed unit (not shown) to the transfer unit X. I'll transport it. Thereafter, the charging process performed on the photosensitive drum 101 by the charger 126 ends at point M in FIG. 2, and the exposure process for the fourth color ends immediately thereafter at point N in FIG. Then, the formed electrostatic latent image is developed using a black developer by the Bk developing roller 111 of the developing device 110, and the developed image using the black developer is superimposed on the yellow+magenta+cyan image.

Also, the registration roller 11 that was being driven at point L in FIG.
4, after conveying the transfer paper 113 to the transfer section
.

The color image superimposed on the photoreceptor drum 101 after the above-described multiple copying steps is... After being transferred onto the transfer paper 113 conveyed in the transfer section by the operation of the transfer device 115, the image is fixed by a fixing section (not shown) and then discharged to the outside of the copying machine.

On the other hand, in response to a control signal from the control unit 127, the static eliminator 117 is turned on to remove the residual developer on the photoreceptor drum 101 (point P in FIG. 2), and at the same time the cleaning device 11
The conductive brush 124 of No. 9 starts rotating, and the bias voltage starts to be applied from the bias power supply 122 to the conductive brush 124 via the bias roller 123 (
Figure 2 point P).

As a result, for example, a bias voltage may be applied to the developer remaining on the photoreceptor drum 101 to be cleaned this time before contacting it as described above. Since the drive has started,
The conductive brush 124 is already in a state where it can electrically attract the developer. Rear conductive plastic brush 124 and photoreceptor drum 1
It is possible to avoid scattering of the developer on the photoreceptor to the surrounding area due to collision with the photoreceptor 01.

Further, after time t2 has elapsed, a control signal is output from the control section 127 to the drive circuit 130, and the solenoid 120
The cleaning device 119 is moved toward the photoreceptor drum 101, the conductive brush 124 is brought into contact with the surface of the photoreceptor drum 101 (point Q in FIG. 2), and the cleaning process is started.

That is, the conductive brush 124 to which a bias voltage is applied brushes off the residual developer on the surface of the photoreceptor drum 101, and the brushed off developer is transferred to the developer conveying screw 11.
B, the developer is sent to a developer recovery section (not shown). Thereafter, the photoreceptor drum 101 is further subjected to static elimination processing by a static elimination lamp 125. Until the next copy start command signal is input. It is kept in standby state.

Next, an embodiment in which the present invention is applied to a color copying system using an intermediate transfer member will be described based on FIGS. 3 and 4.

Regarding parts that overlap with those already explained in FIG. 1, the explanation thereof will be simplified.

301 is a photosensitive drum, 302 is document scanning light from an exposure optical system, and 303 is a developing device (305) having yellow, magenta, cyan, and black developers, respectively.
, 307, 309, 310 are respective developing units, 304, 3
06.308311 are developing rollers), and 312
320 is a static elimination lamp for the photosensitive drum 301, 313 is a static eliminator, 314 is a cleaning device (315 is a developer conveying screw 316 with a conductive brush, 317 is a bias roller, 318 is a bias power supply,
319 is a bias blade), and 321 is a charger for the photosensitive drum 301.

next. An intermediate transfer belt 322 that sequentially transfers the developed image of each color formed on the photosensitive drum 301 and holds the developed image until a series of color copying steps is completed, and a tension roller that stretches the intermediate transfer belt 322. 330 and 1 A transfer device 323 for transferring the developed image on the photosensitive drum 301 to the intermediate transfer body 322, a cleaning device 327 for cleaning residual developer on the intermediate transfer body 322, and the cleaning device 327 in the direction of the arrow. a solenoid 331 that moves the solenoid 331 and a drive circuit 34 that drives the solenoid 331.
1, a registration roller 324 that transports the transfer sheet 325 from a paper feed section (not shown) to a predetermined transfer section Y, and * a registration roller 324 that transports the transfer paper 325 from a paper feed section (not shown) to a predetermined transfer section Y; Transfer device 3 that transfers the colored image
26, and a static eliminator 3 that neutralizes the intermediate transfer belt 322.
It is composed of 43.

Further, the cleaning device 327 cleans the intermediate transfer belt 3.
a conductive brush 329 that comes into contact with the intermediate transfer belt 22 and brushes off residual developer on the intermediate transfer belt;
A bias roller 330 applies a bias voltage from a bias power supply 332 to the bias roller 29, a bias blade 342 cleans the surface of the bias roller, and a developer collecting section (see FIG. The developer is separated from the developer transport screw 328 that transports the developer (not shown).

Also, like the first embodiment, a control section 340 is provided for controlling the entire color copying system.

The operation of the above configuration will be explained using the timing chart shown in FIG.

As shown in the timing chart of FIG. 4, when a copy start command signal is input to the control unit 340, the control unit 340
40 internally processes the copy start command signal and charges the charger 3.
ONL 21 (point A in FIG. 4) The photosensitive drum 301 is uniformly charged. Thereafter, the first color exposure process 302 is executed (point B in FIG. 4), and during that time the cleaning device 327 for the intermediate transfer belt 322 is turned off (point B in FIG. 4).
(point C in the figure), that is. The control unit 340 sends the control signal to the drive circuit 34.
1 to the solenoid 331 to move the cleaning device 327 in the opposite direction to the intermediate transfer belt 322, so that the conductive brush 329 of the cleaning device 327 is in a non-contact state with the intermediate transfer belt 322. Do it like this. However, the rotation of the conductive brush 329 and the application of the bias voltage to the conductive brush 329 continue for a period of time 1 (point E in FIG. 4). As a result, the developer attached to the conductive brush 329 is sent out in the direction of the developer transport screw 118 by driving the conductive brush 329 to which a bias voltage is applied.

During this time, the static eliminator 343 is turned off (point D in FIG. 4).

Furthermore, the exposure process for the first color is completed (point F in Figure 4). The formed electrostatic latent image is developed with a yellow developer by a developing roller 304 of a developing device 305, and the resulting developed image is transferred onto an intermediate transfer belt 322 by a transfer device 323.

Thereafter, the photosensitive drum 301 is neutralized by a static eliminator 313, its surface is cleaned by a cleaning device 314, the static electricity is removed by a static neutralizing lamp 320, and the surface is uniformly charged again by a charger 321.

after that. The second exposure process is performed (from point G in Figure 4 to point H in Figure 4), and the formed electrostatic latent image is transferred to magenta developer by the developing roller 306 of the developing device 307 in the same process as above. The yellow image is developed by the transfer device 323 and transferred onto the first color yellow image held on the intermediate transfer belt 322.

Further, as above, a static eliminator 313. Cleaning device 314
The surface of the photosensitive drum 301 that has been cleaned by the charging device 321 is charged again by the charging device 321. Exposure processing for the third color is executed (from point I in FIG. 4 to point J in FIG. 4).

Thereafter, the formed electrostatic latent image is developed with a cyan developer by a developing roller 308 of a developing device 309 and transferred onto the yellow+magenta image held on the intermediate transfer belt 322.

Furthermore. Through a similar process, a fourth layer is formed on the surface of the photoreceptor drum 301
The color exposure process is started (point K in FIG. 4), and during this time, the registration roller 324 is driven by a control signal from the control unit 340, and the transfer paper 325 is conveyed from the paper feed unit (not shown) to the transfer unit Y. At the same time, the transfer device 326 is also
The control signal from '40 is output and turned ON (Fig. 4L
point).

Thereafter, the charger 321 turns off the charging process for the photosensitive drum 301 (point M in FIG. 4), and the exposure process for the fourth color ends (point N in FIG. 4). The fourth electrostatic latent image formed after that. The photoreceptor tram 3 is developed with black developer by the developing roller 311 of the developing device 310.
01 is developed by the black developer on the intermediate transfer belt 3.
The yellow + magenta + cyan image held on 22 is superimposed and transferred.

continue. When the registration roller 324 conveys the transfer paper 325 to the transfer section Y, the registration roller 324 is turned off.
L (point O in FIG. 4) 1 After that, the conductive brush 3 of the cleaning device 327 is activated based on the control signal from the control unit 340.
29 comes into contact with the intermediate transfer belt 329, ONL,
At the same time as the rotation starts, a bias voltage is applied to the conductive brush 329 from the bias power supply 332 via the bias roller 330 (point P in FIG. 4). As a result, a bias voltage is applied to the developer remaining on the intermediate transfer belt 322 to be cleaned this time before it contacts the intermediate transfer belt 322 and its driving is started, so the conductive plastic brush 329 has already removed the developer. It is in a state where it can be electrically attracted. 32 rear conductive brushes and intermediate transfer drum 322
The developer on the intermediate transfer belt 322 will not be scattered around due to collision.

Thereafter, the static eliminator 343 turns ON (point Q in FIG. 4), and static elimination from the intermediate transfer belt 322 is started.

On the other hand, after a time L2 has elapsed from point P in FIG.
40 outputs a control signal to the drive circuit 341, and the solenoid 331 driven by the drive circuit 341 moves the cleaning device 327 in the direction of the intermediate transfer belt 322 and brings the conductive brush 329 into contact with the intermediate transfer belt 322. Figure 4, point R). As a result, the conductive brush 329 to which a bias voltage is applied brushes off the residual developer on the intermediate transfer belt 322, and the brushed off developer is transferred to the developer storage section (not shown) by the developer transport screw 328. transport.

After the transfer process by the transfer device 326 of the color image on the intermediate transfer belt 322 to the transferred transfer paper 325 is completed (point S in Figure 4), the transfer plate 325 is ejected from the apparatus after undergoing a fixing process. ．． The intermediate transfer belt 322, the photosensitive drum 301, and the surrounding parts are controlled by the control unit 340.
is in a standby state until it receives the next copy start command signal.

As described above, the present invention applies bias voltage to the conductive brush when contacting or releasing the photoreceptor or intermediate transfer member of a cleaning device, and in order to bring the conductive brush into a driving state, the photoreceptor or intermediate transfer member It is possible to prevent the developer adhering to the cleaning brush from remaining as cleaning marks, and also to prevent the developer from scattering to the surroundings.

Further, the present invention does not require any special means for recovering any residual developer from the photoreceptor or intermediate transfer member after the cleaning process, and allows specific control of the conductive brush to be performed using conventional configurations. This can be achieved simply by doing so. Image deterioration can be avoided, the device can be made smaller, manufacturing costs can be reduced, and image deterioration correction can be performed at high speed.

[Effects of the Invention] As explained above, the cleaning device according to the present invention has the following effects:
Even after the cleaning means is in a non-contact state with respect to the photoreceptor or intermediate transfer member, the conductive brush of the cleaning means is driven with a bias voltage applied for a predetermined period of time, and the cleaning means is not in contact with the photoreceptor or intermediate transfer member. Since the control means is provided to drive the conductive brush of the cleaning means with a bias voltage applied for a predetermined period of time before it comes into contact with the transfer body, the brush after cleaning is not brought into contact with the photoreceptor or intermediate transfer body. When cleaning the brush, it is possible to avoid cleaning marks on the photoconductor or intermediate transfer body due to the developer held by the brush, thereby preventing image deterioration. By preventing internal scattering of the developer that occurs when the developer is brought into contact with the transfer body, it is possible to prevent the developer from contaminating the interior of the copying machine or from deteriorating the image due to the developer being mixed into the developing device.

[Brief explanation of the drawing]

Figure 1 is. 1 is a structural explanatory diagram showing a first embodiment of the present invention; FIG. FIG. 2 is a timing chart for each part of the color copying system shown in FIG. 1, FIG. 3 is a structural explanatory diagram showing a second embodiment of the present invention, and FIG. 3 is a timing chart of each part of the color copying system. Description of symbols 101.301 - 1 photosensitive drum 102, 302 - 11 exposure optical system 103, 30.3 - 1 developing device 113, 325, 1 transfer paper 115, 323, 326 - 1 transfer device 117, 313, 343・One static eliminator 119, 314, 327--Cleaning device 120
．． 331・-Solenoid 1 2 2. 3 1'8. 3 3 2--Bias power supply 123, 317, 330--Bias roller 1
24,316,329-・One conductive brush 1 2 6
．． 3 2 1-'74 Electric appliance 127, 340-・Control unit 322...Intermediate transfer belt

Claims (2)

[Claims] (1) The image forming process of charging, exposure, and development is repeated on the photoreceptor, and images based on each image process are sequentially superimposed on the photoreceptor, thereby forming a color image. In a color copying system, the color copying system includes a cleaning means that maintains a non-contact state and returns to a contact state with the photoreceptor after the end of the image forming process to clean residual developer on the photoreceptor, wherein the cleaning means contacts the photoreceptor. Driving the cleaning means with a bias voltage applied continuously for a predetermined period of time even after the state comes into contact with the body, and starting from a predetermined time before the cleaning means comes into contact with the photoreceptor. A cleaning device comprising: a control means for driving the cleaning means with a bias voltage applied thereto. (2) While forming a color image by repeating the image forming process of charging, exposing, and developing on the photoreceptor and sequentially overlaying images based on each image process on an intermediate transfer member close to the photoreceptor, A color copying device having a cleaning means that maintains a non-contact state with respect to the intermediate transfer body and returns to a contact state with the intermediate transfer body after the image forming process ends to clean residual developer on the intermediate transfer body. In the system, the cleaning means continues to be driven with a bias voltage applied for a predetermined period of time even after the cleaning means is brought into a non-contact state with respect to the intermediate transfer member, and the cleaning means continues to be driven with a bias voltage applied to the intermediate transfer member. A cleaning device comprising: a control means for driving the cleaning means with a bias voltage applied thereto for a predetermined period of time before the cleaning means comes into contact with the object.