JP2002174967A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove the large amount of toner stuck to an intermediate transfer body from the intermediate transfer body by using an existing device when image forming is interrupted by abnormal operation such as jamming. SOLUTION: When unnecessary toner is stuck to an intermediate transfer belt 71 in the case that image forming operation is interrupted by the abnormal operation such as the jamming, the intermediate transfer belt is continuously driven so as to pass a toner sticking part through a secondary transfer part. The same bias as that at a normal image forming operation time is applied to a secondary transfer bias roller 81 while the toner sticking part passes through the secondary transfer part, so that an electric field by which the toner is moved from the intermediate transfer body to the side of the secondary transfer bias roller is formed at the secondary transfer part. Thus, at least a part of the toner on the intermediate transfer belt is removed by the secondary transfer bias roller and is recovered by a roller cleaning device 87, and residual toner is removed by a belt cleaning device 79.

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 facsimile, and a printer.
A secondary transfer in which a plurality of toner images formed on an image carrier and formed of toner charged to a predetermined polarity are sequentially superimposed on the intermediate transfer body and primary-transferred, and a transfer material is brought into contact with the intermediate transfer body 2 in the secondary transfer portion between the transfer member and the intermediate transfer member.
Forming a secondary transfer bias, performing secondary transfer of the toner image on the intermediate transfer member onto a transfer material conveyed to the secondary transfer portion, and transferring the transfer residual toner remaining on the intermediate transfer member to the intermediate transfer member. The present invention relates to an image forming apparatus that is removed by a cleaning device.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus,
It has a plurality of image forming units installed along the direction of movement of the surface of the intermediate transfer body, and superimposes the toner images formed on the photoreceptor as an image carrier of each image forming unit on the intermediate transfer body In this case, primary transfer is performed for each transfer, and secondary transfer is performed collectively on transfer paper as a transfer material.
In addition, each developing unit of a developing unit such as a revolver developing device having a plurality of developing units develops a latent image sequentially formed on a single photoconductor, and superimposes each toner image on an intermediate transfer body. Primary transfer, and collectively transfer them on transfer paper for 2
The next transfer is also known.

In such an image forming apparatus, a predetermined latent image is formed on a photosensitive member, the latent image is developed by a developing device corresponding to the latent image, and each toner image is superimposed on an intermediate transfer member. In addition, primary transfer is performed. Then, the toner image on the intermediate transfer body is transferred to a secondary transfer section facing a secondary transfer member such as a secondary transfer roller or a secondary transfer belt for bringing the transfer paper into contact with the intermediate transfer body. Transcribe. During this secondary transfer,
For example, a bias is applied to a secondary transfer roller or the like by a secondary transfer power supply, and a secondary transfer bias is formed between the secondary transfer roller or the like and the intermediate transfer member. Then, the transfer paper is fed to the secondary transfer section at a predetermined timing, and the secondary transfer is performed by moving the toner image on the intermediate transfer member onto the transfer paper by the secondary transfer bias. The transfer residual toner remaining on the intermediate transfer body after the secondary transfer is removed by the intermediate transfer body cleaning device, and the intermediate transfer body proceeds to the next image forming step.

[0004] In such an image forming apparatus, an error occurs in the image forming process when a jam is detected on the paper transport path, or in the charging operation, the writing operation, the developing operation, and the like on the photosensitive member. In this case, the image forming operation of the entire apparatus is generally interrupted. For example, each drive system such as the drive of the photoconductor and the intermediate transfer member is stopped, or the application of a bias for forming the secondary transfer bias is stopped. When the image forming operation is interrupted, if the toner image has already been primary-transferred onto the intermediate transfer member, or if the cause of the operation abnormality has been eliminated and the image forming operation has been resumed, the image forming operation on the photosensitive member has already been completed. In some cases, the applied toner image adheres to the intermediate transfer member. In such a case, the toner image must be removed from the intermediate transfer member before the next image formation is started. Therefore, conventionally, such toner that does not contribute to image formation has been removed by the intermediate transfer body cleaning device.

[0005]

However, the above-described cleaning device for an intermediate transfer member is not suitable for a normal image forming process.
The cleaning device for the intermediate transfer member removes a large amount of toner remaining on the intermediate transfer member without being subjected to the secondary transfer, because it is for removing the transfer residual toner slightly remaining on the intermediate transfer member. Was difficult to remove. In particular, if the toner image to be removed has a plurality of colors, for example, 4
When color toner images are superimposed, it is extremely difficult to remove such a large amount of toner at a time. For this reason, conventionally, a method has been adopted in which the toner not contributing to an image is removed in a plurality of times by the intermediate transfer body cleaning device by idling the intermediate transfer body. However, this method has a problem in that the cleaning efficiency is poor, and it takes time from when the operation abnormality is eliminated to when the next image forming process can be started.

As a method for solving such a problem,
For example, when the cleaning device for an intermediate transfer member removes toner on the intermediate transfer member by a cleaning blade, the cleaning ability can be improved by increasing the contact pressure of the blade. However, when the contact pressure is increased, the surface of the intermediate transfer member is damaged, and the driving load of the intermediate transfer member is increased, which is not practical. Even if other cleaning devices are used, 2
It is extremely difficult to realize a cleaning ability capable of removing a large amount of toner remaining without being transferred next at a time.

It is also conceivable to provide another cleaning device newly and perform cleaning twice. However, a cleaning device that is used only in an emergency such as an operation abnormality such as a jam is provided in the image forming apparatus. It is not preferable to keep the size of the apparatus large and the cost high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and an object of the present invention is to provide a method in which image formation is interrupted due to an abnormal operation such as a jam and toner which does not contribute to image formation is present on an intermediate transfer member. In such a case, an object of the present invention is to provide an image forming apparatus capable of efficiently removing the toner from the intermediate transfer member at a low cost without increasing the size of the apparatus.

[0009]

In order to achieve the above object, according to the present invention, a plurality of toner images formed on an image carrier and formed of toner charged to a predetermined polarity are transferred to the intermediate transfer member. After the primary transfer is performed, the secondary transfer bias is formed at a secondary transfer portion between the secondary transfer member that brings the transfer material into contact with the intermediate transfer member and the intermediate transfer member.
An image forming apparatus for removing a transfer residual toner remaining on the intermediate transfer member by a cleaning device for the intermediate transfer member after the toner image on the intermediate transfer member is secondarily transferred onto a transfer material conveyed to a next transfer portion. In the case where the image forming operation is interrupted due to an operation abnormality and toner not contributing to the image formation is present on the intermediate transfer member, the toner adhering portion on the intermediate transfer member is transferred to the secondary transfer portion. An intermediate transfer member driving means for driving the intermediate transfer member so as to pass through the second transfer member, while the toner adhered portion is passing through the secondary transfer portion. Cleaning bias forming means for forming a cleaning bias to be moved to the side. Here, the “toner that does not contribute to image formation” includes not only the toner that has been primarily transferred onto the intermediate transfer member before the image forming operation was interrupted, but also the intermediate toner in preparation for resuming image formation after the interruption. The toner transferred onto the transfer member is also included.

In this image forming apparatus, while the image forming operation is interrupted due to an operation abnormality due to a jam or other inconvenience, the intermediate transfer member is driven by the intermediate transfer member driving means to drive the image on the intermediate transfer member. The toner not contributing to the formation is moved to the secondary transfer portion. And this toner is 2
While passing through the next transfer section, a cleaning bias is formed in the secondary transfer section by the cleaning bias forming means. The cleaning bias causes the toner to move toward the secondary transfer member. This toner is 2
When the transfer material is present in the next transfer portion, it adheres to the transfer material, and when the transfer material does not exist in the secondary transfer portion, it adheres to the secondary transfer member. Thereby, at least a part of the toner that does not contribute to image formation can be removed from the intermediate transfer member. Further, the toner on the intermediate transfer member that cannot be completely removed by the secondary transfer portion can be removed by the intermediate transfer member cleaning device. In this image forming apparatus, an existing secondary transfer member or transfer material can be used as a cleaning member for cleaning the toner on the intermediate transfer member.

In a second aspect of the present invention, in the image forming apparatus of the first aspect, the cleaning bias forming means is a secondary bias for secondary-transferring the toner image on the intermediate transfer member onto the transfer material. It is a secondary transfer bias forming means for forming a transfer bias.

In this image forming apparatus, the existing secondary transfer bias forming means for forming a secondary transfer bias for moving toner from the intermediate transfer member to the secondary transfer member is used as the cleaning bias forming means. Used.

According to a third aspect of the present invention, in the image forming apparatus of the second aspect, the secondary transfer bias forming means includes:
A bias applying means for applying a bias controlled at a constant voltage to the secondary transfer member, wherein when an image forming operation is interrupted due to an operation abnormality, an electric field formed in the secondary transfer portion by the secondary transfer bias It is characterized by having a bias control means for controlling the bias applying means so as to provide a cleaning bias such that a similar electric field is formed.

When the bias applying means constituting the secondary transfer bias forming means is controlled at a constant voltage, the transfer material is not interposed in the secondary transfer portion at the time of cleaning. It is set so that a suitable electric field is formed when a material is interposed 2
When a cleaning bias is applied in the same manner as the secondary transfer bias, an electric field generated in the secondary transfer portion increases. Since the magnitude of the electric field suitable for moving the toner is determined in accordance with the electrical characteristics of the toner, the change in the electric field lowers the transfer efficiency of the toner during cleaning.
Further, the electric charge is injected into the toner on the intermediate transfer member due to the electric field being too large, so that the toner moving efficiency is reduced. Therefore, in the image forming apparatus according to the present invention, the toner is moved by applying a cleaning bias such that an electric field similar to the electric field formed in the secondary transfer portion is formed by the secondary transfer bias during cleaning. Prevent a decrease in efficiency.

The invention according to claim 4 is the invention according to claim 1 or 2.
In the above image forming apparatus, the secondary transfer bias forming means is a bias applying means for applying a constant current controlled bias to the secondary transfer member.

In this image forming apparatus, since the bias applying means constituting the secondary transfer bias forming means is controlled at a constant current, the electric field generated in the secondary transfer portion depends on the presence or absence of the transfer material. And almost constant. Therefore, it is not necessary to change the applied bias between the secondary transfer and the cleaning.

The invention according to claim 5 is the invention according to claims 1, 2,
In the image forming apparatus of (3) or (4), if the transfer material does not exist in the secondary transfer portion when the image forming operation is interrupted due to an operation abnormality, the drive of the intermediate transfer body is continued without stopping at the time of the interruption. Thus, the present invention is characterized in that it has a control means for controlling the intermediate transfer body driving means and controlling to stop the transfer of the transfer material.

In this image forming apparatus, when the transfer material is not present in the secondary transfer portion when the image forming operation is interrupted, the transfer of the transfer material is stopped when the transfer material is interrupted and the transfer material is transferred to the secondary transfer portion. Keep the material out. In addition, since the transfer material does not exist in the secondary transfer unit, the driving of the intermediate transfer body continues even if other image forming operations are interrupted, and toner not contributing to image formation is directly transferred to the secondary transfer unit. The toner is conveyed and the toner is removed.

Further, the invention according to claim 6 is based on claims 1, 2,
In the image forming apparatus of (3) or (4), when the transfer material is present in the secondary transfer portion when the image forming operation is interrupted due to an operation abnormality, the intermediate transfer body is driven after the cause of the operation abnormality is eliminated. In addition to the above-described control means, the control means controls the intermediate transfer body driving means and controls the cleaning bias forming means so as to form the cleaning bias.

If the image forming operation is interrupted while the transfer material is interposed in the secondary transfer portion due to a jam or the like, the transfer material cannot be carried out of the secondary transfer portion. Toner that does not contribute to image formation cannot be attached to the secondary transfer portion. Further, since the transfer material is stopped at the secondary transfer portion, the toner cannot be efficiently removed from the intermediate transfer member even if the cleaning bias is applied. In the image forming apparatus according to the present invention, even in such a case, first, the transfer material is first taken out of the machine by a user or the like, and the transfer material is removed from the secondary transfer portion, thereby causing an abnormal operation. After the cause is eliminated, when the image forming operation is restarted, the intermediate transfer member is driven, and a cleaning bias is formed to attach and remove the toner on the intermediate transfer member to the secondary transfer member. .

According to a seventh aspect of the present invention, in the image forming apparatus according to the second aspect, the operation is caused by an operation abnormality caused by the transfer material passing through the secondary transfer portion sticking to the intermediate transfer member. When the image forming operation is interrupted in a state where the transfer material is present in the secondary transfer portion, the intermediate transfer member is not changed until toner not contributing to image formation on the intermediate transfer member passes through the secondary transfer portion. And control means for controlling the intermediate transfer member driving means so as to continue without stopping the driving of the intermediate transfer member, and controlling the secondary transfer bias forming means so as to continue without stopping the formation of the secondary transfer bias. It is characterized by the following.

In this image forming apparatus, since the transfer material after the secondary transfer cannot be separated from the surface of the intermediate transfer member, the image forming operation is performed with the rear end portion of the transfer material interposed in the secondary transfer portion. Is stopped, the driving of the intermediate transfer member is continued. By the driving of the intermediate transfer member, the transfer material stuck to the intermediate transfer member is transported as the surface of the intermediate transfer member moves. In addition, by continuing the formation of the secondary transfer bias without stopping, the toner that does not contribute to image formation on the intermediate transfer body is transferred to the transfer material that is adhered to the surface of the intermediate transfer body and is continuously transported. The image is secondarily transferred onto the image. As a result, the toner on the intermediate transfer member adheres to the transfer material and is removed. In this transfer material, all the toner is 2
After the next transfer, the user or the like removes it to the outside of the machine.

[0023] The invention of claim 8 provides the first, second, and third aspects of the present invention.
In the image forming apparatus of any one of 3, 4, 5, and 6, the secondary transfer member contacts the toner when the toner-adhered portion on the intermediate transfer member passes through the secondary transfer portion. The surface is constituted by a member that moves.

In this image forming apparatus, since a surface-moving member such as a secondary transfer roller or a secondary transfer belt is used as the secondary transfer member, it is possible to sequentially move the surface on which toner is not attached. In addition, the toner moved by the cleaning electric field can be more adhered to the secondary transfer member. Further, since the toner on the intermediate transfer member adheres to the surface of the secondary transfer member also by van der Waals force between the intermediate transfer member and the secondary transfer member, the surface on which the toner is not adhered is sequentially moved. The toner can also be adhered to the secondary transfer member by Van der Waals force.

According to a ninth aspect of the present invention, in the image forming apparatus of the eighth aspect, the secondary transfer member is provided while the toner adhering portion on the intermediate transfer member passes through the secondary transfer portion. A speed changing means for making the surface moving speed faster than that during the image forming operation.

In this image forming apparatus, when the toner is removed from the intermediate transfer member by the secondary transfer member, the surface moving speed of the secondary transfer member is increased, so that the toner is removed from the intermediate transfer member at the secondary transfer portion. The surface area of the secondary transfer member that contacts the toner per unit area can be increased. Thereby, the toner moved by the cleaning electric field can be further adhered to the secondary transfer member. In addition, by increasing the surface area of the secondary transfer portion that contacts the toner per unit area in the secondary transfer portion,
Adhesion of toner due to van der Waals force can also be promoted.

According to a tenth aspect of the present invention, in the image forming apparatus of the eighth or ninth aspect, the surface of the secondary transfer member has a ten-point average roughness Rz specified by JIS of 3 μm.
It is characterized by the following.

A secondary transfer member is brought into contact with the toner on the intermediate transfer member, and a cleaning electric field formed between the intermediate transfer member and the secondary transfer member changes according to a minute interval therebetween. . This minute interval changes due to unevenness existing on the surface of the secondary transfer member. That is, unevenness occurs in the cleaning electric field due to the difference between the interval between the peaks of the surface of the intermediate transfer member and the surface of the secondary transfer member and the interval between the peaks of the surface of the intermediate transfer member and the groove of the secondary transfer member. become. In particular,
When the difference between the peak and the valley on the surface of the secondary transfer member is large, when the peak contacts the surface of the intermediate transfer member and the potential of the intermediate transfer member becomes the same as the potential of the secondary transfer portion. At this time, there is a problem that a cleaning electric field is not formed around the contact portion and the toner cannot be moved. In the image forming apparatus according to the present invention, the surface of the secondary transfer member is formed on a smooth surface having a ten-point average roughness Rz of 3 μm or less specified by JIS. The difference between the peaks and valleys on the surface is very small, and the above-described unevenness of the cleaning electric field can be reduced. When the toner adhered on the secondary transfer member is removed from the secondary transfer member, if the toner has a smooth surface as described in the present invention, the toner enters the valley and is scraped off by a blade or the like. Can be reduced.

[0029] The invention of claim 11 is based on claim 1,
In the image forming apparatus of 2, 3, 4, 5, 6, 8, 9 or 10, the toner attached to the secondary transfer member is removed,
And a cleaning unit for cleaning the secondary transfer member.

In this image forming apparatus, the toner adhered to the secondary transfer member by the cleaning bias can be removed from the secondary transfer member by the cleaning unit. Thus, the cleaning ability of the secondary transfer member can be maintained, and no toner stain is generated on the back surface of the transfer material during the secondary transfer in the next image forming process.

[0031] The invention of claim 12 is based on claim 1,
In the image forming apparatus of 2, 3, 4, 5, 6, 8, 9, 10 or 11, the surface of the intermediate transfer member after the toner adhering portion on the intermediate transfer member passes through the secondary transfer portion And a contact / separation means capable of separating the secondary transfer member from the second transfer member.

If the secondary transfer member is brought close to or in contact with the surface of the intermediate transfer member even after the toner-attached portion has passed through the secondary transfer portion, the toner adhered to the secondary transfer member by the cleaning bias is removed. Reverse transfer may occur on the intermediate transfer member due to van der Waals force or the like. In the image forming apparatus according to the present invention, the secondary transfer member is separated from the surface of the intermediate transfer member by the contact / separation means after the toner-adhered portion on the intermediate transfer member that does not contribute to image formation passes through the secondary transfer portion. Accordingly, the toner adhering to the secondary transfer member as described above can be prevented from re-adhering to the intermediate transfer member.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention relates to a wet type electrophotographic copying machine (hereinafter, referred to as "copier") as an image forming apparatus.
An embodiment applied to (1) will be described. In the present embodiment, yellow (hereinafter abbreviated as “Y”), magenta (hereinafter abbreviated as “M”), and cyan (hereinafter abbreviated as “M”).
Abbreviated as "C". ) And black (hereinafter, abbreviated as “Bk”) for forming a full-color image using four color toners.

FIG. 1 is a schematic configuration diagram of a main part of a copying machine according to the present embodiment. This copying machine includes four image forming units 1Y, 1M, 1C, and 1Bk, a laser writing device 30 as a latent image forming unit for irradiating a laser beam L, an intermediate transfer unit 70, and a secondary as a secondary transfer unit. The image forming apparatus includes a transfer unit 80, a fixing device 90, an image reading unit (not shown), a sheet feeding unit, a control unit, and the like. Since the four image forming units 1Y, 1M, 1C, and 1Bk have the same configuration, the following describes the Y image forming unit 1Y using the Y toner.

FIG. 2 is a schematic configuration diagram of the Y image forming unit 1Y. The Y image forming unit 1Y includes a photosensitive drum 10Y as an image carrier, a charger 20Y as a uniform charging unit, a liquid developing device 40Y, a charge removing device 50Y as a charge removing unit, and a photosensitive member cleaning device 60Y having a cleaning blade. , Y developer, and the like.

The liquid developing device 40Y includes a developing roller 41Y as a developer carrier, a developing tank 42Y for storing the liquid developer, and a pumping roller disposed so as to be immersed in the liquid developer in the developing tank. 43Y, and a coating roller 44Y for thinning the liquid developer pumped from the pumping roller and applying the liquid developer to the developing roller 41Y. In the present embodiment, a high-viscosity liquid developer in which toner particles that are visualized particles are dispersed in a high concentration in a carrier liquid that is an insulating solvent is used, and the toner is charged to a positive polarity. I have.

The liquid developing device 40Y is rotatable about a shaft 46Y in the counterclockwise direction in the figure by a contact / separation mechanism including a cam 45Y for bringing the developing roller 41Y into and out of contact with the photosensitive drum 10Y. It has become. The cam receiver 47Y is urged by a spring (not shown) in the counterclockwise direction in the drawing in the tangential direction of the circle about the shaft 46Y, and is maintained in the state of FIG. 2 by the cam 45Y during development.

The liquid developer stored in the developer storage tank 100Y is pumped up by a supply pump 101Y and supplied to the developing tank 42Y of the liquid developing device 40Y. Further, the residual developer remaining on the photoconductor drum 10Y without being primary-transferred is recovered by the photoconductor cleaning device 60Y, and then returned to the developer storage tank 100Y through the recovery passage 102Y. . And
The collected residual developer is mixed with the liquid developer in the developer storage tank 100Y, and is supplied into the development tank 42Y by the supply pump 101Y.

The intermediate transfer unit 70 includes an intermediate transfer belt 71 as an intermediate transfer member and stretching rollers 72, 73, 74, 75, 76, 7 for stretching the intermediate transfer belt.
And 7, a primary transfer bias forming means including primary transfer bias rollers 78Y, 78M, 78C, and 78Bk, and a belt cleaning device 79 as an intermediate transfer body cleaning device having a cleaning blade.

The intermediate transfer belt 71 has a tension roller 7
1, 2, 3, 7, 74, 75, 76, and 77 and each of the photosensitive drums 10Y, 10M, 10C, and 10Bk are stretched so as to have a predetermined tension, and can be moved in the direction of arrow A in FIG. I have. Further, the primary transfer bias rollers 78Y, 78M, 78C, 78Bk are arranged opposite to the photosensitive drums 10Y, 10M, 10C, 10Bk via the intermediate transfer belt 71, respectively. A predetermined primary transfer bias is applied to these primary transfer bias rollers 78Y, 78M, 78C, 78Bk from a primary transfer power source (not shown).

FIG. 3 is a schematic structural view of the secondary transfer unit 80. The secondary transfer unit 80 includes a secondary transfer bias roller 81 as a secondary transfer member, a secondary transfer power source 86 as a bias applying means connected to the secondary transfer bias roller, and a surface of the secondary transfer bias roller. The apparatus includes a roller cleaning device 87 as cleaning means for cleaning, a contact / separation mechanism 88 as contact / separation means, and the like.

The secondary transfer bias roller 81 is a JI
It is formed so as to have a smooth surface having a ten-point average roughness Rz specified by S of 3 μm or less. The secondary transfer bias roller 81 is connected to the intermediate transfer unit 70.
And a secondary transfer bias forming means together with the secondary transfer power source.
A secondary transfer bias is formed between the belt and the intermediate transfer belt 71. The secondary transfer power supply 86 applies a constant current controlled bias to the secondary transfer bias roller 81.

Next, an image forming operation of the copying machine according to the present embodiment will be described. In the copying machine, as shown in FIG. 2, the photosensitive drum 10Y is uniformly charged by the charger 20Y while being driven to rotate in the direction of arrow B, and then the laser beam L from the laser writing device 30 is irradiated. Photoreceptor drum 1
A Y electrostatic latent image is formed on 0Y. On the other hand, the developing tank 42
Pumping roller 43 immersed in liquid developer in Y
The liquid developer attached to Y is applied on developing roller 41Y via application roller 44Y, for example, to a thickness of about 0.5 to 20 μm. Then, the developing roller 41Y is brought into contact with the photosensitive drum 10Y, and the Y electrostatic latent image formed on the surface of the photosensitive drum is reversely developed with the toner in the liquid developer. At the time of development, a predetermined developing bias is applied between the developing roller 41Y and the photosensitive drum, and the toner on the developing roller moves in the carrier liquid and is applied to the Y electrostatic latent image portion on the photosensitive drum. Adsorb electrostatically.

As shown in FIG. 1, the Y toner image formed by the development is converted into a Y primary image in which the photosensitive drum and the intermediate transfer belt 71 come into contact with the rotation of the photosensitive drum 10Y as shown in FIG. It is transported to the transfer section. In the Y primary transfer section, a negative bias voltage, for example,-(minus) 300 to -500 V is applied to the back surface of the intermediate transfer belt 71 by the primary transfer bias roller 78Y. Then, the Y toner image on the photosensitive drum 10Y is attracted to the intermediate transfer belt 71 by the primary transfer electric field generated by the application of the bias, and the primary transfer is performed on the intermediate transfer belt. Hereinafter, similarly, the M toner image, C
The toner image and the Bk toner image are also
The primary transfer is performed so as to be sequentially superimposed on the toner image.

As described above, the toner images of four colors overlapping on the intermediate transfer belt 71 are opposed to the secondary transfer bias roller 81 by the rotation of the intermediate transfer belt.
It is transported to the next transfer section. Further, a transfer paper P as a transfer material is conveyed to the secondary transfer unit by a registration roller 82 at a predetermined timing from a paper supply unit (not shown) in a direction indicated by an arrow C in FIG. The secondary transfer bias roller 81
Is brought into contact with the intermediate transfer belt 71 by the contact / separation mechanism 88 at a predetermined timing, and is supplied with a negative bias voltage, for example, −800 to −2000 by the secondary transfer power supply 86.
V is applied. Then, by the secondary transfer electric field generated by the bias application and the contact pressure at the secondary transfer portion,
The toner image on the intermediate transfer belt 71 is attracted to the transfer paper P, and secondarily transferred collectively on the transfer paper.

Thereafter, the transfer paper P on which the toner image has been secondarily transferred is separated from the intermediate transfer belt 71 by the separation device 85, and after being subjected to a fixing process by the fixing device 90, is discharged from the apparatus main body. On the other hand, the photosensitive drum 10 after the primary transfer
In Y, the residual charge is removed by the charge removing device 50Y shown in FIG. 2, the surface thereof is cleaned by the photoreceptor cleaning device 60Y, the residual developer is collected and removed, and the image is prepared for the next image forming operation. Further, the intermediate transfer belt 71 after the secondary transfer is cleaned by the belt cleaning device 79 shown in FIG. 1 to collect and remove the residual developer, and prepare for the next image forming operation.

Next, the operation of the above-described copying machine when the operation is abnormal, which is a characteristic part of the present invention, will be described. In the above copying machine, when a jam is detected by the registration sensor 83 and the separation sensor 91 provided on the transfer path of the transfer paper P, the belt wrap sensor 92 and the roller wrap sensor 84 provided outside the transfer path, and the like. Or the photosensitive drum 10
When an error occurs in the charging operation, the writing operation, the developing operation, and the like for the Y, 10M, 10C, and 10Bk, the control unit applies various driving systems, primary transfer bias, and the like to interrupt the image forming operation. An emergency stop command for emergency stop is issued.

[Control Example 1] First, the transfer paper P jammed on the transport path between the paper feed unit (not shown) and the registration roller 82, or the transfer paper P could not be taken out from the paper feed unit. A control example (hereinafter, this control example is referred to as “control example 1”) of the control operation of the copier when the transfer paper P is jammed before being conveyed to the secondary transfer unit due to the cause will be described. When such a jam occurs, the control unit recognizes the jam based on a detection signal output when the registration sensor 83 does not detect the transfer sheet P even after a predetermined sheet feeding timing has elapsed.

FIG. 4 is a flowchart showing the flow of control by the control unit in this control example. Upon receiving the detection signal (S1), the control unit outputs an emergency stop command to each unit (S2). As a result, the image forming operation of each section is interrupted, but the cleaning operation for removing the toner adhered on the intermediate transfer belt 71 is continued, and the intermediate transfer belt is cleaned (S3).

FIG. 5 is a timing chart showing the operation of each part related to the cleaning of the intermediate transfer belt 71. Image forming operations that are not involved in the cleaning operation, such as the optical writing operation and the transfer material transfer operation by the transfer material transfer unit, are interrupted when the emergency stop command is received. The primary transfer bias in each primary transfer unit may be stopped. However, when the primary transfer bias is stopped, the intermediate transfer belt 7 is stopped.
Applying the primary transfer bias of the primary transfer unit on the downstream side may cause reverse transfer in which the toner attached on the primary transfer unit adheres on the photosensitive drum at the primary transfer unit on the downstream side. May be performed continuously.

The intermediate transfer member driving means (not shown) for driving the intermediate transfer belt 71 continues the same operation as a normal image forming operation even when receiving the emergency stop command. The photosensitive drums 10Y, 10M, 10C, and 10Bk rotating with the intermediate transfer belt 71 also continue to be driven. Further, the secondary transfer power supply 86 and the contact / separation mechanism 88 of the secondary transfer unit 80 continue to operate even when the emergency stop command is received. Here, the secondary transfer power source 8
6 performs the same operation as the normal image forming operation, but the contact / separation mechanism 88 causes the secondary transfer bias roller 81 to move the intermediate transfer belt 71 slightly earlier than the normal image forming operation (broken line portion in FIG. 5). (Solid line in FIG. 5). This separation timing is immediately after the toner adhering portion on the intermediate transfer belt 71 has passed through the secondary transfer portion. This can prevent the toner that has once adhered to the secondary transfer member from re-adhering to the intermediate transfer belt.

As in this control example, when the image forming operation is interrupted, the driving of the intermediate transfer belt 71 is continued, so that the toner on the intermediate transfer belt is subjected to the secondary transfer in the same manner as in the normal image forming operation. Moved to the department. In the secondary transfer section, a secondary transfer electric field is formed in the same manner as in a normal image forming operation, and the toner on the intermediate transfer belt 71 is moved toward the secondary transfer bias roller 81 by the electric field. I do. Since the transfer sheet P does not exist in the secondary transfer portion, the toner on the intermediate transfer belt 71 adheres to the secondary transfer bias roller 81. By cleaning the secondary transfer portion, a part of the toner on the intermediate transfer belt 71 is removed from the intermediate transfer belt.

When the toner on the intermediate transfer belt 71 is cleaned by the secondary transfer section, the surface moving speed of the secondary transfer bias roller 81 may be increased.
In this case, the contact area of the surface of the secondary transfer bias roller 81 contacting the toner per unit area on the intermediate transfer belt 71 in the secondary transfer portion can be increased, and more toner can be transferred to the secondary transfer bias roller 81. Can be adhered to. Therefore, the secondary transfer bias roller 81
Cleaning effect can be improved.

The toner on the intermediate transfer belt 71 that has not been completely removed by the secondary transfer portion is removed by the belt cleaning device 79 as the intermediate transfer belt is driven. Since a part of the toner on the intermediate transfer belt 71 that has reached the portion facing the belt cleaning device 79 has been removed in the secondary transfer portion, the toner is cleaned by the belt cleaning device. Can be sufficiently cleaned.

The toner adhered to the secondary transfer bias roller 81 is removed from the secondary transfer bias roller by the roller cleaning device 87 and collected. The roller cleaning device 87 includes a cleaning roller 87a that comes into contact with the secondary transfer bias roller 81 and rotates so as to move at the contact portion in a direction opposite to the surface of the secondary transfer bias roller. , A blade 87b contacting the surface of the cleaning roller, and a storage unit 8 for storing toner scraped off by the blade.
7c. An electric field for moving the toner from the secondary transfer bias roller to the cleaning roller 87a side is formed by applying the bias of the power supply to the toner attached to the secondary transfer bias roller 81. The toner is removed from the secondary transfer bias roller by the electric field and the rubbing force of the cleaning roller 87a. Then, the toner attached to the cleaning roller 87a is scraped off by the blade 87b, rises up, falls into the accommodating portion 87c, and is collected.

As the cleaning means for cleaning the secondary transfer bias roller 81, for example, another cleaning device such as a cleaning device for bringing a cleaning blade into contact with the secondary transfer bias roller to scrape off the toner on the roller is used. Can be applied. As the cleaning blade, a cleaning blade formed of a urethane material can be used. The toner used in the exemplary embodiment has an average particle size of 1 to 2 μm. For this reason, in the secondary transfer bias roller 81 having a smooth surface with Rz of 3 μm or less, there is almost no problem that the toner completely enters the valley of the surface and cannot be scraped off by the cleaning blade. . Therefore, it is possible to prevent the toner that has entered the valley from adhering to the back surface of the transfer paper P in the next image forming step and causing the back surface to become soiled with toner.

As described above, when the toner on the intermediate transfer belt 71 is removed by the belt cleaning device 79, each of the photosensitive drums 10Y, 10M, 10C, 10B.
k and the driving of the intermediate transfer belt 71 are stopped. Thus, the cleaning of the intermediate transfer belt 71 is completed.

When the cleaning of the intermediate transfer belt 71 is completed, the control section displays a message indicating that a jam has occurred and the location of the jam on a display panel (not shown) of the copying machine (S4). To remove the transfer paper P which is jammed. Then, the user sets the transfer paper P
Is removed, and a predetermined preparation for resuming the image forming operation is performed by closing the cover of the copying machine or pressing a predetermined button (S5). Then, by completing this preparation and restarting the image forming operation, the image forming operation of the image that could not be formed due to the jam is performed again (S6).

As described above, according to this control example, after the image forming operation is interrupted due to the jam, the cleaning of the intermediate transfer belt 71 is continuously performed. Rather, the time required for the restart preparation can be greatly reduced. Unnecessary toner adhering to the intermediate transfer belt 71 due to a jam is cleaned twice by the secondary transfer bias roller 81 of the secondary transfer unit and the belt cleaning device 79, so that the conventional toner is removed. In addition, there is no need to idle the intermediate transfer belt 71, and the time required for cleaning the intermediate transfer belt is considerably reduced.

After the rear end of the transfer sheet P has passed through the secondary transfer section, for example, when a jam occurs in the fixing device 90, the transfer sheet P is transferred to the secondary transfer section in the same manner as in this control example. Since there is no control, the control unit can execute the control operation of the present control example. In this case, at the time of single copying, the toner does not adhere to the intermediate transfer belt 71, so that it is not necessary to clean the intermediate transfer belt 71 using the secondary transfer bias roller 81. However, at the time of continuous copying, even when the transfer paper P has passed through the secondary transfer portion, toner from the next image forming operation is
Therefore, the same control operation as in the present control example is performed.

[Control Example 2] Next, the transfer paper P is transferred to the separation device 8.
5 during the secondary transfer, that is, the transfer paper P
A control example (hereinafter, this control example is referred to as “control example 2”) of the control operation of the copying machine when a jam occurs when the rear end of the copier exists in the secondary transfer unit will be described. When such a jam occurs, the control unit detects that the trailing end of the transfer paper P has passed through the registration roller 82 as scheduled by the registration sensor 83, but the separation sensor 91 determines that A detection signal that is output when the transfer paper P is not detected even after the timing has elapsed, or a detection signal that is output when the separation sensor 91 continues to detect the transfer paper P even after the predetermined transport time has passed. The jam is recognized by the signal.

FIG. 6 is a flowchart showing the flow of control by the control unit in this control example, and FIG. 7 is a timing chart showing the operation of each unit related to the cleaning of the intermediate transfer belt 71. Upon receiving the detection signal (S1), the control unit outputs an emergency stop command to each unit (S2). Thereby, as shown in FIG.
The driving of the photosensitive drums 10Y, 10M, 10C, 10Bk and the intermediate transfer belt 71, the operation of the secondary transfer unit 80, and all other image forming operations are interrupted.

Here, since the flywheel is used for the drive system of the photosensitive drum of the present embodiment, even if this emergency stop command is issued, the surface of the photosensitive drum is 10 to 20 mm.
mm and then stops, and the intermediate transfer belt 71 that rotates with the photosensitive drum also stops at the same timing. Secondary transfer bias roller 81 by secondary transfer power supply 86
Is stopped simultaneously with the emergency stop command, the toner adhering to the surface of the intermediate transfer belt for the inertial rotation after the emergency stop command passes through the secondary transfer portion as it is, and The cleaning device 79 may not be able to completely remove the toner. Therefore, in the present control example, as shown in FIG. 7, the above-described second step, such as applying a bias by the secondary transfer power supply 86 and driving the secondary transfer bias roller 81, is performed.
The operation of the next transfer unit is continued until the inertial rotation time of the intermediate transfer belt elapses after receiving the emergency stop command, and then the operation is stopped. Thus, the toner passing through the secondary transfer unit after the emergency stop command can be removed from the intermediate transfer belt 71 by the secondary transfer bias roller 81.

After interrupting all the image forming operations, the control section displays a message indicating that a jam has occurred and the location of the jam on the display panel (not shown) of the copying machine (S).
3). Then, the user is requested to remove the transfer paper P jammed in the copying machine. The user removes the transfer paper P and closes the cover of the copying machine or presses a predetermined button to prepare for restarting the image forming operation (S4).

In the preparation for the restart, when the control unit outputs a restart preparation command, each photosensitive drum 10
Y, 10M, 10C, 10Bk and the intermediate transfer belt 7
A drive system such as 1 and other predetermined units make predetermined preparations for resumption. When this preparation is started, the leading end of the toner adhering portion on the intermediate transfer belt 71 is located immediately before the secondary transfer portion. Therefore, the secondary transfer power supply 86
At the same time as receiving the restart preparation command, bias application to the secondary transfer bias roller 81 is started. This allows
The toner on the intermediate transfer belt 71 is removed by the secondary transfer bias roller 81 simultaneously with the start of preparation, and the remaining toner is removed by the belt cleaning device 79. Then, by completing this preparation and restarting the image forming operation, the image forming operation of the image that could not be formed due to the jam is performed again (S5).

Also in this control example, immediately after the toner adhering portion on the intermediate transfer belt 71 has passed through the secondary transfer portion, the secondary transfer bias roller 81 is moved by the contact / separation mechanism 88 to perform the intermediate transfer. Move away from the belt 71.

As described above, according to the present control example, the unnecessary toner adhered to the intermediate transfer belt 71 due to the jam is removed twice by the secondary transfer bias roller 81 of the secondary transfer portion and the belt cleaning device 79. Since the cleaning is performed separately, there is no need to idle the intermediate transfer belt 71 as in the related art, and the time required for cleaning the intermediate transfer belt is considerably shortened. Time can be reduced.

If a jam occurs during the secondary transfer due to the leading edge of the transfer paper P being caught in the secondary transfer bias roller 81, the jam is detected by the roller take-in sensor 84 shown in FIG. The detection signal is sent to the control unit. In this case, the same control operation as in the present control example is performed.

[Control Example 3] Next, the transfer paper P is transferred to the separation device 8.
5 cannot be separated from the intermediate transfer belt 71, but is stuck on the intermediate transfer belt, and is caught in the intermediate transfer belt. A control example of the control operation (hereinafter, this control example is referred to as “control example 3”) will be described. When such a jam occurs, the control unit recognizes the jam based on a detection signal output when the transfer sheet P is detected by the belt wrap sensor 92.

The cleaning operation of the intermediate transfer belt 71 according to this control example is the same as that of the above-described control example 1 shown in FIGS. That is, when the control unit receives the detection signal, the control unit outputs an emergency stop command to each unit, thereby outputting each of the photosensitive drums 10Y, 10M, 10C, and 10Bk.
The driving of the intermediate transfer belt 71 and the operation of the secondary transfer unit 80 continue, and other image forming operations are interrupted. When the drive of the intermediate transfer belt 71 is continued after the emergency stop command, the transfer paper P adhered to the intermediate transfer belt is
Is transported as the surface of the intermediate transfer belt moves.
At this time, since the bias application by the secondary transfer power supply 86 is also continued, a secondary transfer electric field is formed in the secondary transfer portion. Therefore, the toner on the intermediate transfer belt 71 is secondarily transferred onto the transfer paper P adhered to the surface of the intermediate transfer belt and conveyed, similarly to the normal image forming operation. Thereby, the toner on the intermediate transfer belt 71 is
The toner adheres to the transfer paper P and is removed.

The difference between the present control example and the above control example 1 is that the drive of the intermediate transfer belt 71 is stopped immediately after the rear end of the transfer paper P passes through the secondary transfer section. The stop timing of the belt is earlier than in the control example 1. When the intermediate transfer belt 71 is stopped and all image forming operations are interrupted in this way, the fact that a jam has occurred and the location where the jam has occurred are displayed on a display panel (not shown) of the copying machine. The transfer paper P jammed in the copier is removed. Subsequent operations are the same as in the control example 1.

As described above, according to the present control example, after the image forming operation is interrupted when the transfer paper P is entangled in the intermediate transfer belt 71 and a jam occurs, the intermediate transfer belt 71 is continuously cleaned. The time for the preparation for resumption can be significantly reduced as compared with the conventional cleaning which is performed during the preparation for resumption after removing the paper P. Unnecessary toner adhering to the intermediate transfer belt 71 due to a jam is cleaned by the transfer paper P of the secondary transfer portion and the belt cleaning device 79 in two separate steps. There is no need to idle the belt 71, and the time required for cleaning the intermediate transfer belt is considerably reduced.

Although the embodiment has been described with reference to the wet type image forming apparatus, the present invention is also applicable to a dry type image forming apparatus. Further, in the present embodiment, the tandem type image forming apparatus has been described. However, each developing device of a developing unit such as a revolver developing device develops a latent image sequentially formed on a single photosensitive drum, and The same can be applied to the case where a toner image is superimposed on an intermediate transfer member.

The secondary transfer power supply in this embodiment applies a constant current controlled bias to the secondary transfer bias roller 81, but applies a constant voltage controlled bias to the secondary transfer bias roller 81. Is also good. In the case of the constant voltage control, the transfer paper P does not intervene in the secondary transfer portion at the time of cleaning, so the electric field generated in the secondary transfer portion is larger than that at the time of the secondary transfer. . In order to prevent the toner transfer efficiency from lowering, it is preferable to control the cleaning bias so that an electric field similar to the electric field during the secondary transfer is formed at the time of cleaning. In the control example 3 in which the transfer paper P is interposed in the secondary transfer section at the time of cleaning, it is not necessary to control the bias of the secondary transfer power supply 86 by the constant voltage control.

[0075]

According to the first to twelfth aspects of the invention, the toner on the intermediate transfer member when the image formation is interrupted due to an abnormal operation is first adhered to the secondary transfer member or the transfer material. Since the toner can be removed in two cleaning operations of collecting by the transfer body cleaning device, there is an excellent effect that the toner can be efficiently removed from the intermediate transfer body. Furthermore, 2
Since the existing transfer member is used as the cleaning member necessary for attaching to the next transfer member or the transfer material, there is also an excellent effect that the apparatus is not enlarged and the cost is reduced.

In particular, according to the second aspect of the invention, since the existing cleaning bias forming means is used, there is an excellent effect that the size and cost of the apparatus can be further reduced.

According to the third aspect of the present invention, it is possible to prevent a decrease in toner transfer efficiency during cleaning which may occur in an apparatus for forming a secondary transfer bias by constant current control.
There is an excellent effect that a reduction in the cleaning effect in the next transfer portion can be prevented.

According to the fourth aspect of the present invention, there is no need to change the applied bias between the secondary transfer and the cleaning, so that there is an excellent effect that the control can be simplified.

According to the fifth and seventh aspects of the present invention, the cleaning operation for removing the toner on the intermediate transfer member can be performed continuously after the image forming operation is interrupted.
There is an excellent effect that the time required to shift to the next image forming step can be reduced.

According to the invention of claim 6, even if a transfer material is interposed in the secondary transfer portion when the image forming operation is interrupted,
There is an excellent effect that cleaning can be performed in the next transfer portion.

According to the eighth to tenth aspects of the present invention,
Since more toner can be attached to the secondary transfer member, there is an excellent effect that the cleaning effect by the secondary transfer member can be enhanced.

According to the eleventh aspect of the present invention, it is possible to maintain the cleaning ability of the secondary transfer member and to prevent toner stain on the back surface of the transfer material at the time of secondary transfer in the next image forming step. Has an excellent effect.

According to the twelfth aspect of the invention, there is an excellent effect that the toner adhered to the secondary transfer member can be prevented from re-adhering to the intermediate transfer member.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a copying machine according to an embodiment.

FIG. 2 is a schematic configuration diagram of a Y image forming unit in the copying machine.

FIG. 3 is a schematic configuration diagram of a secondary transfer unit in the copying machine.

FIG. 4 is a flowchart illustrating a flow of control by a control unit in a control example 1.

FIG. 5 is a timing chart showing an operation of each unit related to intermediate transfer belt cleaning when an emergency stop command is received in the control example.

FIG. 6 is a flowchart illustrating a flow of control by a control unit in a control example 2;

FIG. 7 is a timing chart showing an operation of each unit related to intermediate transfer belt cleaning when an emergency stop command is received in the control example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming unit 10 Photoconductor drum 20 Charger 30 Laser writing device 40 Liquid developing device 41 Developing roller 50 Static eliminator 60 Photoconductor cleaning device 70 Intermediate transfer unit 71 Intermediate transfer belt 79 Belt cleaning device 80 Secondary transfer unit 81 2 Next transfer bias roller 82 Registration roller 83 Registration sensor 84 Roller winding sensor 85 Separation device 86 Secondary transfer power supply 87 Roller cleaning device 88 Contact / separation mechanism 91 Separation sensor 92 Belt winding sensor 90 Fixing device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) // G03G 15/10 112 G03G 15/10 112 F term (reference) 2H027 DC04 DC05 DC14 ED16 ED24 ED27 EE03 EF13 EK09 2H030 AA00 AB02 BB02 BB23 BB42 BB46 BB53 BB54 BB56 2H032 AA05 AA15 BA09 BA23 BA30 CA02 CA04 CA13 2H074 AA03 AA41 BB02 BB32 DD07 3J103 AA02 FA07 GA57 GA58 GA60 HA04 HA20

Claims (12)

[Claims] 1. A method according to claim 1, wherein a plurality of toner images formed on the image carrier and formed of toner charged to a predetermined polarity are sequentially superimposed on the intermediate transfer body and primary-transferred, and then the transfer material is transferred to the intermediate transfer body. Between the secondary transfer member and the intermediate transfer member,
A secondary transfer bias is formed at the next transfer section, and after the toner image on the intermediate transfer body is secondarily transferred onto a transfer material conveyed to the secondary transfer section, a transfer residue remaining on the intermediate transfer body is formed. In an image forming apparatus that removes toner with an intermediate transfer body cleaning device, when an image forming operation is interrupted due to an operation abnormality and toner not contributing to image formation is present on the intermediate transfer body, the intermediate transfer is performed. An intermediate transfer member driving means for driving the intermediate transfer member such that the toner-adhered portion on the body passes through the secondary transfer portion; and And a cleaning bias forming means for forming a cleaning bias for moving the toner from the intermediate transfer member to the secondary transfer member. 2. The image forming apparatus according to claim 1, wherein the cleaning bias forming means forms a secondary transfer bias for secondary transferring the toner image on the intermediate transfer member onto the transfer material. An image forming apparatus, which is a transfer bias forming unit. 3. The image forming apparatus according to claim 2, wherein
The secondary transfer bias forming means has a bias applying means for applying a bias controlled at a constant voltage to the secondary transfer member.
An image forming apparatus comprising: a bias control unit that controls the bias applying unit such that the cleaning bias is such that an electric field similar to the electric field formed in the secondary transfer unit is formed by the next transfer bias. apparatus. 4. An image forming apparatus according to claim 1, wherein
The image forming apparatus according to claim 1, wherein the secondary transfer bias forming unit is a bias applying unit that applies a constant current controlled bias to the secondary transfer member. 5. The image forming apparatus according to claim 1, wherein when the image forming operation is interrupted due to an abnormal operation, the transfer material is not present in the secondary transfer section.
An image having control means for controlling the intermediate transfer body driving means so as to continue the driving of the intermediate transfer body without stopping it, and for controlling the conveyance of the transfer material to be stopped. Forming equipment. 6. The image forming apparatus according to claim 1, wherein when the transfer material is present in the secondary transfer portion when the image forming operation is interrupted due to an operation abnormality, the cause of the operation abnormality is eliminated. The image forming apparatus further includes a control unit that controls the intermediate transfer body driving unit to drive the intermediate transfer body and controls the cleaning bias forming unit to form the cleaning bias. Forming equipment. 7. The image forming apparatus according to claim 2, wherein
Due to an operation abnormality caused by the transfer material passing through the next transfer portion sticking to the intermediate transfer body, the transfer material is
When the image forming operation is interrupted in a state where the intermediate transfer member is present in the next transfer portion, the driving of the intermediate transfer member is stopped until toner not contributing to image formation on the intermediate transfer member passes through the secondary transfer portion. And control means for controlling the secondary transfer bias forming means so as to continue without stopping the formation of the secondary transfer bias. Image forming device. 8. The image forming apparatus according to claim 1, wherein the secondary transfer member is configured such that a portion of the intermediate transfer member to which the toner adheres passes through the secondary transfer portion. An image forming apparatus characterized in that the surface of the image forming apparatus which is in contact with the toner is configured to move when the image forming apparatus is operating. 9. The image forming apparatus according to claim 8, wherein the surface movement speed of the secondary transfer member is controlled while the toner adhering portion on the intermediate transfer member passes through the secondary transfer portion.
An image forming apparatus, comprising: a speed changing unit that makes the speed faster than during an image forming operation. 10. The image forming apparatus according to claim 8, wherein the surface of the secondary transfer member has a ten-point average roughness Rz specified by JIS of 3 μm or less. . 11. The method of claim 1, 2, 3, 4, 5, 6, 8, or 9.
Alternatively, in the image forming apparatus according to the tenth aspect, the image forming apparatus further includes a cleaning unit that removes the toner attached to the secondary transfer member and cleans the secondary transfer member. 12. The method of claim 1, 2, 3, 4, 5, 6, 8,
In the image forming apparatus according to any one of 9, 10 and 11, the secondary transfer member can be separated from the surface of the intermediate transfer member after the toner adhering portion on the intermediate transfer member passes through the secondary transfer portion. An image forming apparatus comprising: