JP2002214998A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of restraining the deterioration of image quality by preventing banding or the like caused by the tilt of bristles of a brush type member abutting on a toner image carrier when a machine is not used for a long time. SOLUTION: By rotating a cleaning brush 203 for a specified time or more at the time of supplying power, the tilt of bristles formed because the brush 203 is still kept in contact with a photoreceptor drum 200 when the machine is not used before is restored, so that an image defect caused by the tilt of the bristles is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and the like.
For example, the present invention relates to an image forming apparatus provided with a toner image carrier such as an intermediate transfer member.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a toner image formed on a toner image carrier such as a photoreceptor or a transfer belt is transferred to a transfer belt or a transfer paper and the remaining toner is cleaned. . As the cleaning means, a cleaning brush which rotates so that the surface moves is often used.

[0003]

However, if the image forming operation is not performed for a long period of time, the cleaning brush does not rotate, so that a certain part of the hair remains in contact with the toner image carrier, and only that part of the hair remains. Deformation (hair fall)
In some cases. If the image forming operation is performed while the hairs are still falling, when the cleaning brush rotates, the rotation load of the cleaning brush on the toner image carrier changes between the hair falling portion and the normal portion, and the image is printed on the image. A stripe pattern (periodical density change) called banding occurs, which causes a problem of deteriorating image quality.

In the invention disclosed in Japanese Patent Application Laid-Open No. 3-269777, this phenomenon is prevented by rotating the brush when a new cartridge including the cleaning brush is inserted into the machine. However, the phenomenon associated with hair fall as described above occurs more frequently when the machine is not used for a long time than when the brush is new, so that the invention disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-269777 has a sufficient solution. Was not turned on.

[0005] A brush that rotates so that its surface moves may be provided in an image forming apparatus for purposes other than cleaning. For example, a conventional image forming apparatus includes a brush used as an application unit for applying a lubricant such as zinc stearate to an application target such as a transfer belt, a transfer paper transport member that carries and transports a transfer paper, and a toner image carrier. There is known a device provided with a brush or the like for neutralizing an object to be neutralized. Even with such a brush, if the image forming operation is not performed for a long period of time, as described above, a certain amount of hair remains in contact with the application target and the static elimination target,
Only that part is in a state where the hair has fallen. In this case, if the image forming operation is performed while the hair is still falling, when the brush rotates, the rotation load of the brush on the object to be applied and the object to be neutralized changes between the part where the hair has fallen and the normal part, and The contact state with the object to be neutralized becomes uneven. as a result,
It is not possible to uniformly apply the lubricant to the object to be applied or to uniformly remove the charge from the object to be neutralized, which also causes a problem of deteriorating the image quality.

The present invention has been made in view of the above-mentioned conventional problems,
It is an object of the present invention to provide an image forming apparatus capable of preventing banding or the like due to brush hair fall when a machine has not been used for a long time and capable of suppressing deterioration of image quality.

[0007]

According to a first aspect of the present invention, there is provided an image forming apparatus in which a brush-like member is brought into contact with a predetermined contact object during an image forming operation in order to achieve the above object. Wherein the surface moving means moves the surface of the brush-like member for a predetermined time during a non-image forming operation period. In this image forming apparatus, if the brush-shaped member is disposed at a position where the brush-shaped member comes into contact with a predetermined contact target, the non-image forming operation period is extended over a long period of time. Can occur. However, in the present image forming apparatus, the surface moving means moves the surface of the brush-like member for a predetermined period of time during the non-image forming period.
During the non-image forming period, the portion of the brush-like member that contacts the contact target can be changed. Thus, it is possible to prevent the brush-shaped member from coming into contact with the contact target at the same portion for a long time. Further, even when some hair falls off, the surface of the brush-shaped member is moved for a predetermined time during the non-image forming period as in the present image forming apparatus.
The broken part can be returned. As described above, according to the present image forming apparatus, it is possible to suppress the hair falling phenomenon of the brush-like member.

[0008]

[Embodiment 1] Embodiments of the present invention will be described below with reference to the drawings. In the following description, an embodiment in which the present invention is applied to an electrophotographic color copying machine (hereinafter, referred to as “color copying machine”) as an example of an image forming apparatus (hereinafter, this embodiment is referred to as “ Mode 1 ”) will be described, but it goes without saying that the present invention is not limited to a copying machine.

First, a schematic configuration and operation of the color copying machine according to the present embodiment will be described with reference to FIG. This color copier includes a color image reading device (hereinafter, referred to as “color scanner”) 1, a color image recording device (hereinafter, referred to as “color scanner”).
It is called "color printer". ) 2, paper feed bank 3 and the like.

The color scanner 1 includes a contact glass 1
Illumination lamp 122 and mirror group 1
The image is formed on the color sensor 125 via the lenses 23a, 123b, 123c and the lens 124, and the color image information of the document 4 is represented by, for example, red (Red: hereinafter "R") and green (Green: hereinafter "G"). .), Blue (Blue:
Hereinafter, it is referred to as “B”. ) Is read for each color separation light and converted into an electric image signal. Here, the color sensor 125
Is composed of R, G, B color separation means and a photoelectric conversion element such as a CCD in this example, and
Scanning color images at the same time. Then, based on the R, G, and B color separation image signal intensity levels obtained by the color scanner 1, color conversion processing is performed by an image processing unit (not shown), and black (Black: hereinafter, referred to as “Bk”). , Yellow (hereinafter referred to as “Y”), cyan (Cyan: hereinafter referred to as “C”), magenta (M
agenta: Hereinafter referred to as “M”. ) Is obtained.

The operation of the color scanner 1 for obtaining the color image data of Bk, Y, C and M is as follows. Upon receiving a scanner start signal which is timed with the operation of the color printer 2 described later, an optical system including the illumination lamp 122 and mirror groups 123a, 123b, 123c scans the document 4 in the left direction of the arrow in FIG. Color image data of one color is obtained for each scan of. By repeating this operation four times in total, for example, each color separation light of R, G, B is read and converted into an electric image signal. Alternatively, R, G, and B image data are stored in the memory. When a memory (not shown) is used, R, G, B in one scan
Image data of three colors is obtained. Then, each time the color printer 2 sequentially visualizes and superimposes the images to form a final four-color full-color image. Based on the intensity levels of the R, G, and B color separation image signals obtained by the color scanner, a color conversion process is performed by an image processing unit (not shown), and the Bk, Y, C, and M image data are processed. Get.

FIG. 2 is a schematic configuration diagram of a color printer 2 which is a main part of the color copying machine of FIG. The color printer 2 includes a photosensitive drum 200 as a toner image carrier rotating in a counterclockwise direction as indicated by an arrow in the figure, a charging charger 201 as a charging unit, a cleaning blade 202, and a cleaning brush as a brush-like member. (Fur brush) 203, a photosensitive member cleaning device 300 as a cleaning unit, a discharging lamp 206 as a discharging unit, a potential sensor 204, a development density pattern detector 205, and a writing optical unit 220 (FIG. 2).
Shows only the laser beam L for exposure. ), A revolver developing unit 230 as a developing device, an intermediate transfer unit 500, a secondary transfer unit 600 as a transfer device, a fixing unit 700 using a pair of fixing rollers 701, and the like. Of these, the writing optical unit 22
0 and the revolver developing unit 230 function as a toner image forming unit.

A writing optical unit 220 converts color image data from the color scanner 1 into an optical signal, and applies a laser beam corresponding to an image of a document on the surface of the photosensitive drum 200 uniformly charged by the charger 201. L
To perform optical writing to form an electrostatic latent image on the surface of the photosensitive drum 200. This writing optical unit 2
Reference numeral 20 denotes, for example, a semiconductor laser as a light source, a laser emission drive control unit, a polygon mirror and its rotation motor, f
/ Θ lens, reflection mirror, etc.

The revolver developing unit 230 includes a Bk developing device 231 using Bk toner, a Y developing device 232 using Y toner, a C developing device 233 using C toner, an M developing device 234 using M toner, and a half unit. It is constituted by a developing revolver driving unit (not shown) that rotates clockwise. Each of the developing devices 231 to 234 installed in the revolver developing unit 230 is a developing device as a developing material carrier that rotates by contacting the ears of the developer with the surface of the photosensitive drum 200 in order to develop an electrostatic latent image. It comprises a sleeve, a developer paddle that rotates to pump up and agitate the developer, and a developing sleeve drive unit that rotates the developing sleeve clockwise as indicated by the arrow in the figure.

In this embodiment, each of the developing units 231 to 234 is
The toner inside is charged to a negative polarity by stirring with the ferrite carrier, and a developing bias power supply (not shown) is applied to each developing sleeve to a negative DC voltage Vdc (DC component) and an AC voltage Vac (AC). ) Is applied, and each developing sleeve is biased to a predetermined voltage with respect to the metal base layer of the photosensitive drum 200.

In a standby state of the main body of the color copying machine, the revolver developing unit 230 is stopped at the home position where the Bk developing unit 231 is located at the developing position, and when the copy start key is pressed, reading of the original image data is started. Then, based on the color image data, optical writing with the laser light L, that is, formation of an electrostatic latent image starts. Hereinafter, the electrostatic latent image based on the Bk image data is referred to as “Bk electrostatic latent image”.
That. The same applies to Y, C, and M.

In order to enable development from the front end of the Bk electrostatic latent image, before the front end of the electrostatic latent image reaches the Bk development position, the rotation of the Bk developing sleeve is started to start the Bk electrostatic latent image. Is developed with Bk toner. Thereafter, the developing operation of the Bk electrostatic latent image is continued. When the trailing end of the Bk electrostatic latent image passes the Bk developing position, the revolver is immediately moved until the next color developing machine comes to the developing position. The developing unit 230 rotates. This is completed at least before the leading end of the electrostatic latent image based on the next image data reaches the developing position.

The intermediate transfer unit 500 includes an intermediate transfer belt 501, which is an intermediate transfer member as a toner image carrier, which is stretched over a plurality of rollers described later. Around the intermediate transfer belt 501, a secondary transfer belt 601 as a transfer material carrier of the secondary transfer unit 600,
Secondary transfer bias roller 6 as secondary transfer charge applying means
05, a belt cleaning blade 504 as an intermediate transfer body cleaning unit, a lubricant applying brush 505 as a brush applying member as a lubricant applying unit and a charge removing unit
Are disposed so as to face each other.

The intermediate transfer belt 501 includes a primary transfer bias roller 507, a belt driving roller 508, a belt tension roller 509, a secondary transfer opposing roller 510, and a cleaning opposing roller 51 as primary transfer charge applying means.
1 and the earth roller 512. Each roller is formed of a conductive material, and is a primary transfer bias roller 5.
Each roller other than 07 is grounded. Further, a position detection mark is provided on the outer peripheral surface or the inner peripheral surface of the intermediate transfer belt 501. However, on the outer peripheral surface side of the intermediate transfer belt 501, it is necessary to devise a method for providing a position detection mark so as to avoid the pass area of the belt cleaning device 504, and there is a case where it is difficult to arrange the mark. A position detection mark is provided on the inner peripheral surface side of the intermediate transfer belt 501. The optical sensor 514 as a mark detection sensor includes:
It is provided at a position between the bias roller 507 and the drive roller 508 around which the intermediate transfer belt 501 is stretched.

The primary transfer bias roller 507 is supplied with a primary transfer power supply 801 controlled by a constant current or a constant voltage.
A transfer bias controlled to a predetermined current or voltage according to the number of superimposed toner images is applied. Further, the intermediate transfer belt 501 is driven by a drive motor (not shown) in a belt drive roller 5
08 drives in the direction of the arrow in the figure. The intermediate transfer belt 501 is made of a semiconductor or an insulator, as described later,
It has a single-layer or multilayer structure.

A transfer section for transferring the toner image on the photosensitive drum 200 to the intermediate transfer belt 501 (hereinafter referred to as a “primary transfer section”)
That. In (1), the intermediate transfer belt 501 is stretched by the primary transfer bias roller 507 and the earth roller 512 so as to be pressed against the photosensitive drum 200 side, so that a predetermined width is provided between the photosensitive drum 200 and the intermediate transfer belt 501. Is formed.

The lubricant applying brush 505 polishes the zinc stearate 506 as a lubricant formed in a plate shape by rotating the brush, and applies the polished fine particles to the intermediate transfer belt 501. The lubricant application brush 505 is also configured to be able to be adjacent to the intermediate transfer belt 501, and is provided at a predetermined timing.
Is controlled to come into contact with. The lubricant application brush 505 also functions as a charge removing brush for removing charges remaining on the intermediate transfer belt 501 after the secondary transfer. The neutralizing brush may be configured separately from the lubricant application brush 505.

The secondary transfer unit 600 includes a secondary transfer belt 601 and the like stretched over three support rollers 602, 603, and 604, and a stretched portion between the support rollers 602 and 603 of the intermediate transfer belt 501 is formed. Secondary transfer opposing roller 5
10 can be pressed against. One of the three support rollers 602, 603, and 604 is a driving roller that is rotationally driven by a driving unit (not shown), and the driving roller drives the secondary transfer belt 601 in a direction indicated by an arrow in the drawing. .

The secondary transfer bias roller 605 is a secondary transfer means, and is disposed so as to sandwich the intermediate transfer belt 501 and the secondary transfer belt 601 between the secondary transfer opposing roller 510 and is controlled at a constant current. A transfer bias of a predetermined current is applied by a secondary transfer power supply 802. Also 2
Next transfer belt 601 and secondary transfer bias roller 605
A separation mechanism (not shown) for driving the support roller 602 and the secondary transfer bias roller 605 in the direction of the arrow is provided so that the support roller 602 and the secondary transfer bias roller 605 can take a position where the roller is pressed against the secondary transfer opposing roller 510 and a position where the roller is separated. ing. The secondary transfer belt 601 and the support roller 602 at the separated position are
Is shown by a two-dot chain line.

In the figure, reference numeral 650 denotes a pair of registration rollers.
Next transfer bias roller 605 and secondary transfer facing roller 51
The transfer paper P, which is a transfer material, is fed at a predetermined timing between the intermediate transfer belt 501 and the secondary transfer belt 601 sandwiched between 0 and 0.

The fixing roller pair 70 of the secondary transfer belt 601
A transfer paper discharging charger 606 serving as a transfer material discharging unit and a belt discharging charger 607 serving as a transfer material carrier discharging unit oppose a portion stretched around the support roller 603 on the first side (the left side in FIG. 2). is set up. Further, a cleaning blade 608 serving as a transfer material carrier cleaning unit is in contact with a portion of the secondary transfer belt 601 which is stretched around the lower support roller 604 in the drawing.

The transfer paper discharging charger 606 discharges the electric charges held in the transfer paper so that the transfer paper can be separated from the secondary transfer belt 601 by the strength of the transfer paper itself. is there. The belt static elimination charger 607 eliminates electric charges remaining on the secondary transfer belt 601. The cleaning blade 60
Numeral 8 is for cleaning by removing the deposits attached to the surface of the secondary transfer belt 601.

In the color copier constructed as described above, when an image forming cycle of A4-size transfer paper is started, the drive motor (not shown) and the photosensitive drum 200 move in the counterclockwise direction indicated by an arrow. Transfer belt 50
Numeral 1 rotates at the same linear velocity as indicated by the arrow at the primary transfer position. A mark MC is provided on the back side of the intermediate transfer belt 501. This mark MC is the intermediate transfer belt 50
The optical sensor 514 is attached to a stationary member in a predetermined passage area that moves together with the mark MC and passes the mark MC.

As the optical sensor 514, a reflection type photo sensor or a transmission type photo sensor is used. When a reflection type photo sensor is used as the optical sensor 514, a member such as a reflective tape is attached to the intermediate transfer belt 501, and the reflection type photo sensor applies the mark MC from the surface with low reflectivity on the intermediate transfer belt 501 to the mark MC. What is necessary is just to read the change, or the change from the mark MC to the surface of the intermediate transfer belt 501 with low reflectivity.

As the intermediate transfer belt 501 rotates, Bk
The primary transfer is performed by the transfer bias by the voltage applied to the primary transfer bias roller 507 in the formation of two toner images, two Y toner images, two C toner images, and two M toner images. Specifically, two screens of toner images are formed on the intermediate transfer belt 501 in the order of Bk, Y, C, and M.

For example, a Bk toner image is formed as follows. The charging charger 201 uniformly charges the surface of the photosensitive drum 200 to a predetermined potential with negative charges by corona discharge. After a predetermined time from the detection of the mark MC by the optical sensor 514, the following optical writing based on the BK image data is performed. Then, based on the color image signal converted from the image data stored in the RGB memory by a writing optical unit (not shown), raster exposure with Bk data laser light is performed. When this raster image is exposed, the photosensitive drum 2 which is initially uniformly charged
In the exposed portion of the surface of No. 00, charges proportional to the amount of exposure light disappear, and a Bk electrostatic latent image is formed. When the negatively charged Bk toner on the Bk developing roller of the Bk developing device 231 comes into contact with the Bk electrostatic latent image, the toner does not adhere to the portion of the photosensitive drum 200 where the charge remains,
The toner is attracted to a portion having no charge, that is, an exposed portion, and a Bk toner image similar to the electrostatic latent image is formed. The Bk toner image formed on the photosensitive drum 200 is transferred to the surface of the intermediate transfer belt 501 that is driven at a constant speed in a state of contact with the photosensitive drum 200. Hereinafter, the photosensitive drum 2
The transfer of the toner image from 00 to the intermediate transfer belt 501 is referred to as “primary transfer”. Photoreceptor drum 20 after belt transfer
A small amount of untransferred residual toner remaining on the surface of the photosensitive drum 200 is cleaned by the photosensitive drum cleaning device 300 in preparation for reuse of the photosensitive drum 200.

In the same manner, the mark MC is detected by the optical sensor 514 every time the intermediate transfer belt 501 makes one rotation.
On the photoconductor drum 200 side, after the Bk image forming process,
At the same timing as k, that is, a predetermined time after the detection of the mark MC by the optical sensor 514, optical writing with Y image data, optical writing with C image data, and optical writing with M image data are performed. When the process proceeds to the Y image forming process, the RG
Calling of the converted Y image data from the B memory starts, and a Y electrostatic latent image is formed on the surface of the photosensitive drum 200 by writing the laser light with the Y image data. Then, after the rear end of the previous Bk electrostatic latent image has passed and before the front end of the Y electrostatic latent image has arrived, the rotating operation of the revolver developing unit 230 is performed, and the Y developing device 232 is rotated.
Is set to the developing position, and the Y electrostatic latent image is developed with the Y toner.

Thereafter, development of the Y electrostatic latent image area is continued.
When the rear end of the Y electrostatic latent image has passed, the rotation operation of the revolver developing unit is performed as in the case of the Bk developing device 231 described above, and the next C developing device 233 is moved to the developing position.
This is also completed before the leading end of the next C electrostatic latent image reaches the developing position. In the image forming processes of C and M, the operations of retrieving the color image data, forming the electrostatic latent image, and developing are the same as those of the above-described processes of Bk and Y, and thus the description is omitted.

On the intermediate transfer belt 501, Bk, Y, C, and M toner images sequentially formed on the photosensitive drum 200 are transferred onto the same surface while being sequentially aligned. As a result, two screens of a toner image in which a maximum of four colors are superimposed are formed on the intermediate transfer belt 501.

At the time when the above-mentioned image forming operation is started,
The transfer paper P is fed from a paper feed unit such as a transfer paper cassette or a manual feed tray of the paper feed bank 3, and a registration roller pair 650 is provided.
Waiting at the nip. 2 where a nip is formed by the secondary transfer facing roller 510 and the secondary transfer bias roller
Before the leading end of the toner image on the intermediate transfer belt 501 reaches the next transfer portion, the secondary transfer contact / separation clutch operates, and the secondary transfer unit 600 contacts the intermediate transfer belt 501.
Thereafter, the registration roller pair 650 is driven such that the leading end of the transfer paper P coincides with the leading end of the toner image, and the transfer paper P
And the toner image are registered. Then, the transfer paper P is superimposed on the toner image on the intermediate transfer belt 501 and passes through the secondary transfer portion. At this time, the secondary transfer power supply 80
2, the transfer bias by the voltage applied to the secondary transfer bias roller 605 causes the intermediate transfer belt 501
The upper four-color superimposed toner image is collectively transferred onto the transfer paper. This is called “secondary transfer”.

When the paper P passes through a portion facing the transfer paper discharging charger 606 disposed downstream of the secondary transfer portion in the moving direction of the secondary transfer belt 601, the transfer paper P is discharged, and the secondary transfer belt 601 is discharged. From the fixing roller pair 701. Then, the fixing roller pair 70
The toner image is fused and fixed at the nip portion 1 and sent out of the apparatus body by a discharge roller pair (not shown), and is stacked face up on a copy tray (not shown) to obtain a full-color copy.

On the other hand, the transfer residual toner remaining on the surface of the photosensitive drum 200 after the primary transfer is transferred to a cleaning brush 203 and a cleaning blade 2 which are driven to rotate by a driving force from a driving device (not shown) as a surface moving means.
02, the photosensitive member cleaning device 300
And is uniformly discharged by a discharge lamp (not shown). The transfer residual toner remaining on the surface of the intermediate transfer belt 501 after the transfer of the toner image onto the transfer paper P is cleaned by a belt cleaning blade 504 pressed against the intermediate transfer belt 501 by a separation / contact mechanism (not shown). .

Here, in the case of the repeat copy, the operation of the color scanner 1 and the image formation on the photosensitive drum 200 follow the image formation process of the first sheet of the fourth color (M).
At a predetermined timing, the process proceeds to the image forming process for the first color (Bk) of the second sheet. Further, the intermediate transfer belt 501 transfers the second sheet of Bk toner to the area of the surface cleaned by the belt cleaning blade 504 following the batch transfer step of the first sheet of four-color superimposed toner image onto transfer paper. The image is transferred to the belt. Thereafter, the operation is the same as that of the first sheet.

The above is the copy mode for obtaining a four-color full-color copy. However, in the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. Become. In the case of the single-color copy mode, only the developing device of the predetermined color of the revolver developing unit 230 is in the developing operation state until the predetermined number of sheets is completed, and the belt cleaning blade 504 is pressed against the intermediate transfer belt 501. The copy operation is performed with the position as it is.

In the above color copier, unless the image forming operation is performed for a long period of time, the cleaning brush 203 and the lubricant applying brush 505 do not rotate. Stay in contact with Therefore, only that portion is deformed (hair falls). Cleaning brush 2
FIG. 3 shows a state where 03 has fallen. As shown in the figure, if the above-described image forming operation is performed in a state where the hair has fallen, when the cleaning brush 203 rotates, the photosensitive drum 20 is separated between the fallen portion and the normal portion.
It has already been described that the rotational load of the brush with respect to 0 changes and a stripe pattern (periodic density change) called banding occurs on the image.
The longer the time during which the image forming operation is not performed (pause time), the larger the time. In addition, while in contact with the predetermined contact target,
In the case of a brush-like member whose surface is moved by a driving device or the like as a surface moving means, the state of fluctuation in rotation tends to increase as the pause time increases, and the same applies to the lubricant application brush 505. FIG. 4 shows the relationship between the pause time and the rotation fluctuation rate.

As shown in FIG. 4, if the pause time becomes longer, the rotation fluctuation rate also gradually increases. However, the rotation fluctuation value saturates at b after time a. In order to prevent the above-described banding from occurring and causing no problem on the image, it is necessary to suppress the value of the rotation fluctuation rate to c or less. For this purpose, the cleaning brush 203 may be rotated for a predetermined time during the pause time to restore the hair from falling. In FIG. 4, the cleaning brush 203 is described as an example. However, the value c of the rotation fluctuation rate for achieving a level that does not cause a problem on an image differs depending on the use, material, and the like of the brush.

FIG. 5 shows the rotation fluctuation rate after the cleaning brush 203 in which the rotation fluctuation rate is the saturated state value b in FIG. 4 for a certain period of time. Since it is only necessary to set this value to the value c or less, if the photosensitive drum 200 is rotated only for the time d, it is possible to eliminate the influence on the image due to the falling of the cleaning brush 203. In addition, if the brush-shaped member is moved in a surface by a driving device or the like as a surface moving unit in a state of being in contact with a predetermined contact target, the rotation fluctuation when the brush-shaped member in a hair-tipped state is rotated for a certain period of time. The change in rate is shown in FIG.
And the same applies to the lubricant application brush 505.

In the first embodiment of the present invention, the cleaning brush 203 is rotated for more than the time d when the power is turned on, thereby preventing an image defect due to the fall of the hair formed when the machine is not used before. In addition, when the power is turned on, rotating the cleaning brush 203 alone delays the rising time. Therefore, according to the first embodiment of the present invention, this is performed simultaneously with warming up of the fixing unit 700 and the like. Shall be.

In the color copying machine according to the present embodiment, process control may be performed when the power is turned on. Here, the process control specifically refers to mainly the amount of adhered toner and the surface potential of the photosensitive drum 200, and the potential sensor 204 and the development density pattern detector 205.
And control for setting the amount of light, the charging potential, the developing bias, the toner supply amount, and the like of the optical writing unit 220 based on the detection result. By such control, toner replenishment control, setting of each potential, setting of light amount, gamma correction, and the like are performed, and are fed back to appropriate image forming conditions. In the process control, there is no need to actually output an image on the transfer paper P.
A reference image such as a latent image or a toner image (patch image) may be formed on the photosensitive drum 200 or the intermediate transfer belt 501, and may be detected by the potential sensor 204, the development density pattern detector 205, or the like. However, when the hairs of the cleaning brush 203 or the like are rotated during the formation of such a reference image, banding occurs as in the image forming operation. If the reference image is affected by banding or the like, proper image formation is performed. Conditions may go wrong. Therefore, it is desirable to rotate the cleaning brush 203 before such a process control operation, more specifically, before a reference image used in the process control is formed.

[Embodiment 2] Next, similarly to the above embodiment, an embodiment in which the present invention is applied to a color copying machine which is an example of an image forming apparatus (hereinafter, this embodiment is referred to as "Embodiment 2") ") Is explained. Embodiment 1
In the above, the color copying machine including one photosensitive drum 200 and the revolver developing unit 230 has been described. In the second embodiment, a so-called tandem type color copying machine including a plurality of photosensitive drums will be described. Since the configuration of the color scanner is the same as that of the first embodiment, a color printer will be described below.

FIG. 6 is a partially enlarged view of the color printer. In this color printer, photosensitive drums 200C, 200M, 200Y, and 200B as four toner image carriers each carrying a toner image of C, M, Y, and Bk.
Is provided. Each photoconductor drum 200C, 200
The first embodiment around M, 200Y, and 200B
Similarly to the above, the photoreceptor cleaning device 300 as a cleaning device including a charging charger 201 as a charging device, a cleaning blade 202 and a cleaning brush 203 as a brush-like member, a developing unit 235 as a developing device, an intermediate transfer unit 500, and a transfer device The image forming apparatus includes a secondary transfer unit 600 as an apparatus, a fixing unit 700 using a fixing roller pair 701, and the like.

In this color copying machine, the individual photosensitive drums 200C, 200M, 200Y, 200B rotate,
First, the chargers 201C, 201M, 201Y, 2
01B, the surface of the photoconductor drum is uniformly charged, and then the laser beam L is irradiated from the above-described writing optical unit in accordance with the content read by the color scanner, so that each of the photoconductor drums 200C, 200M, 200Y, 200B is respectively exposed. A corresponding electrostatic latent image is formed. Thereafter, each of the electrostatic latent images is developed by the developing units 235C, 235M, 235Y, and 235B, and each of the photosensitive drums 200C, 200M, and 2B.
Bk, Y, C, and M toner images are formed on 00Y and 200B, respectively. The toner images of the respective colors are primary-transferred onto the surface of the intermediate transfer belt 501 so as to overlap each other, and the four-color superimposed toner image on the intermediate transfer belt 501 is transferred by a transfer bias caused by a voltage applied to a secondary transfer bias roller 605. Is transferred collectively onto the transfer paper P. Thereafter, the transfer paper P on the secondary transfer belt 601 is
The toner image is separated from the next transfer belt 601 and sent to the fixing roller pair 701. The toner image is melted and fixed at the nip portion of the fixing roller pair 701. The toner image is sent out of the apparatus main body by the discharge roller pair (not shown), and is not shown. It is stacked face up on a copy tray to obtain a full color copy.

In the color copying machine according to the second embodiment, similarly to the first embodiment, the cleaning brushes 203M, 203C, 203Y, and 203Bk as brush-like members are provided.
Further, a lubricant application brush 505 is provided. Furthermore,
This color copying machine is provided with a belt cleaning brush 513 as a brush-like member in addition to the belt cleaning blade 504 as an intermediate transfer body cleaning unit. Further, in this color copying machine, a cleaning brush 609 which is a brush-like member is provided as a transfer material carrier cleaning means instead of the cleaning blade 608 in the first embodiment.

Also in the second embodiment of the present invention, the cleaning brushes 203M, 203C, 203Y, and 203Bk, the lubricant applying brush 505, and the belt cleaning brush 51 are driven by a driving device (not shown) as surface moving means.
3 and the cleaning brush 609 are rotated. As a result, it is possible to prevent image defects due to hair fall formed when the machine is not used before turning on the power. When the power is turned on, it is desirable that these brushes are not rotated independently and are performed simultaneously with warming up of the fixing unit 700 and the like.
Further, when performing the process control at the time of turning on the power, it is preferable to rotate before the process control, as in the first embodiment.

As described above, the color copying machine as the image forming apparatus according to the first and second embodiments provides the photosensitive drum 200 as a predetermined contact target during the image forming operation.
And a driving device (not shown) as a surface moving means for moving the surface in a state where the cleaning brush 203 as a brush-like member is in contact with the cleaning brush 203 for a predetermined time during the non-image forming operation. Is moved over the surface, so that the cleaning brush 203 etc.
It is possible to prevent contact with 00, etc., and to restore the broken part. Therefore, the hair falling phenomenon of the cleaning brush 203 and the like can be suppressed, and the occurrence of banding, poor contact of the brush, and the like can be prevented, and the deterioration of image quality can be suppressed. Further, the color copying machines according to the first and second embodiments have a configuration in which a photoconductor drum 200 or an intermediate transfer belt 501 as a toner image carrier and a toner image forming device that forms a toner image with toner on the photoconductor drum 200 and the like are provided. Writing optical unit 220 as means
A developing device 230, 235 or a primary transfer bias roller 507; and a transfer device 1 for transferring a toner image formed on the photosensitive drum 200 or the like to an intermediate transfer belt 501 or transfer paper P as a material to be transferred. Since the cleaning brush or the like, which includes the secondary transfer bias roller 507 or the secondary transfer unit 600 and is in contact with the photosensitive drum 200 carrying the toner image, is moved during the non-image forming operation, an abnormal image due to banding is generated. Can be prevented. Further, the color copying machines according to the first and second embodiments employ a cleaning brush 2 that contacts the photosensitive drum 200 or the intermediate transfer belt 501 and removes transfer residual toner remaining on the photosensitive drum 200 and the like.
03 and the belt cleaning brush 513 or the cleaning brush 609 are moved on the surface during the non-image forming operation, so that cleaning is generally performed at a relatively high contact pressure among brush-like members that come into contact with the toner image carrier. , And an abnormal image due to banding can be more effectively prevented. Further, as described above, by starting the surface movement of the cleaning brush 203 or the like when the power is turned on, the power is not turned on so that a certain portion of the cleaning brush 203 or the like generally remains in contact with the contact object for the longest time. An image forming operation can be performed after returning the hair fall that has occurred in between, and an abnormal image due to the brush fall can be stably prevented. In addition, as described above, by moving the cleaning brush 203 and the like during the warm-up time of each unit in the apparatus such as the fixing unit 700, the above-described effect of preventing the abnormal image due to the fall of the brush bristles and the brush-like member There is no need to take extra time for the rotation, and the rise time is not delayed. In particular, if the surface moving means moves the surface of the cleaning brush 203 or the like before the process control operation performed during the warm-up time, in addition to the above-described effect of preventing an abnormal image due to brush hair falling, The image created at the time of control can also be prevented from being affected by banding or the like due to the fall of the brush hair, and the image quality can be prevented from deteriorating.

In the first and second embodiments,
Although the case where the cleaning brush 203 and the like are rotated when the power is turned on has been described, the cleaning brush 203 and the like may be periodically rotated during a suspension period while the power is turned on.

[0052]

According to the first aspect of the present invention, as described above, the image forming operation is performed from the time when the power is turned on until the image forming operation can be actually started, or while the power is turned on. By rotating a brush-like member such as a cleaning brush and moving the surface thereof during a non-image forming period such as a rest period where cleaning is not performed, there is an effect that an abnormal image due to brush hair fall can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a schematic configuration of a color copying machine according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a color printer which is a main part of the color copying machine of FIG.

FIG. 3 is a schematic view showing a state in which hair has fallen on a cleaning brush.

FIG. 4 is a diagram illustrating a relationship between a machine downtime and a rotation variation rate of a photoconductor.

FIG. 5 is a diagram illustrating a relationship between a rotation time of a cleaning brush and a rotation variation rate of a photosensitive drum.

FIG. 6 is a schematic configuration diagram of a color printer that is a main part of a color copying machine according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Color scanner 2 Color printer 3 Paper supply bank 4 Document 200 Photoconductor drum 201 Charging charger 202 Cleaning blade 203 Cleaning brush 204 Potential sensor 205 Developing density pattern detector 206 Static electricity removing lamp 220 Optical writing unit 230 Revolver developing unit 235 Developing unit 300 Photoconductor Cleaning Device 500 Intermediate Transfer Unit 501 Intermediate Transfer Belt 505 Lubricant Application Brush 507 Primary Transfer Bias Roller 508 Belt Drive Roller 513 Belt Cleaning Brush 514 Optical Sensor 600 Secondary Transfer Unit 601 Secondary Transfer Belt 602-604 Support Roller 605 Secondary transfer bias roller 609 Cleaning brush 650 Registration roller pair 700 Fixing unit 701 Fixing low To-801 primary transfer power supply 802 secondary transfer power supply

Claims (6)

[Claims] 1. An image forming apparatus comprising a surface moving means for moving a surface of a brush-like member in contact with a predetermined contact object during an image forming operation, wherein the surface moving means comprises a non-image forming operation. An image forming apparatus, wherein the surface of the brush-like member is moved for a predetermined time during the period. 2. The image forming apparatus according to claim 1, wherein the toner image carrier, a toner image forming means for forming a toner image by toner on the toner image carrier, and a toner formed on the toner image carrier. An image forming apparatus, comprising: a transfer device that transfers an image to a transfer material; wherein the predetermined contact target is the toner image carrier. 3. The image forming apparatus according to claim 2, wherein the brush-like member is a cleaning brush that comes into contact with the toner image carrier and removes transfer residual toner remaining on the toner image carrier. Image forming apparatus. 4. An image forming apparatus according to claim 1, wherein said surface moving means starts surface movement of said brush-like member when power is turned on. 5. An image forming apparatus according to claim 1, wherein said surface moving means moves the surface of said brush-like member during a warm-up time of each part in the apparatus. Forming equipment. 6. An image forming apparatus according to claim 5, wherein said surface moving means moves the surface of said brush-like member before a process control operation performed during said warm-up time. Forming equipment.