JP6929512B2 - Transfer device and image forming device - Google Patents

Description

The present invention relates to a transfer device and an image forming device.

Conventionally, a transfer device that sandwiches a recording material (paper) between an image holder and a transfer member to transfer an image on the image holder onto the recording material, and an image forming device provided with such a transfer device are known. Has been done.

For example, Patent Document 1 discloses a technique in which a transfer drum rotates by transmitting a rotational drive from a photosensitive drum.

Japanese Unexamined Patent Publication No. 2001-2020

In recent years, a configuration has been proposed in which an image holder and a transfer member are independently driven in a transfer device. In this configuration, in order to stabilize the drive system on the image holder side, it is conceivable to control the drive speed on the transfer member side to be slower than that on the image holder side. However, the drive system on the image holder side is twisted due to the speed difference from the transfer member side, and when the recording material rushes into the transfer region, the twist is momentarily released and there is a possibility that rotational vibration occurs in the image holder. Such rotational vibration causes pixel shift in image formation with respect to the image holder.

Therefore, an object of the present invention is to suppress rotational vibration of the image holder due to the inrush of the recording material, as compared with the case where the driving speed on the transfer member side is constant.

The transfer device according to claim 1 is
An image holder that at least circulates around the peripheral surface and holds an image on the peripheral surface,
A transfer member in which at least the peripheral surface circulates and passes through a transfer region between the image holder and the image holder so that the image on the image holder is transferred to the recording material.
During the transfer of an image to the recording material by driving the transfer member, the peripheral speed of the transfer member is controlled to a first peripheral speed lower than the peripheral speed of the image holder, and the recording material controls the peripheral speed. Before entering the transfer region, a driver that temporarily increases the peripheral speed of the transfer member to a second peripheral speed higher than the first peripheral speed,
To be equipped.

The transfer device according to claim 2 is the transfer device according to claim 1.
The drive stops the temporary increase to the second peripheral speed before the recording material enters the transfer region, and returns the transfer member to the first peripheral speed. be.

The transfer device according to claim 3 is the transfer device according to claim 1 or 2.
A detector is provided to detect the tip of the recording material toward the transfer region before entering the transfer region.
The drive increases the speed of the transfer member from the first peripheral speed to the second peripheral speed, triggered by the detection of the tip by the detector.

The transfer device according to claim 4 is the transfer device according to any one of claims 1 to 3.
The driver increases the second peripheral speed to a peripheral speed higher than the peripheral speed of the image holder.

The transfer device according to claim 5 is the transfer device according to claims 1 to 4.
The drive causes a temporary increase in speed from the first peripheral speed to the second peripheral speed in the drive system of the image holder as it is driven at the first peripheral speed. It continues for more than the time that the twist is released.

The transfer device according to claim 6 is the transfer device according to claims 1 to 5.
The image holder is driven by a driving force transmitted via a coupler.
The drive stops the temporary acceleration from the first peripheral speed to the second peripheral speed in less than the time when the coupler is disengaged.

The image forming apparatus according to claim 7 is
An image holder that at least circulates around the peripheral surface and holds an image on the peripheral surface,
A former that forms an image on the peripheral surface of the image holder,
A transfer member in which at least the peripheral surface circulates and passes through a transfer region between the image holder and the recording material so that the image on the image holder is transferred to the recording material.
During the transfer of an image to the recording material by driving the transfer member, the peripheral speed of the transfer member is controlled to a first peripheral speed lower than the peripheral speed of the image holder, and the recording material controls the peripheral speed. Before entering the transfer region, a driver that temporarily increases the peripheral speed of the transfer member to a second peripheral speed higher than the first peripheral speed,
To be equipped.

According to the transfer device according to claim 1 and the image forming device according to claim 7, the rotational vibration of the image holder due to the inrush of the recording material is suppressed as compared with the case where the drive speed on the transfer member side is constant. Can be done.

According to the transfer apparatus according to claim 2, it is possible to avoid the winding of the recording material around the image holder, which occurs when the speed increase is continued even after the recording material is rushed.

According to the transfer device according to claim 3, it is easier to control the start of speed increase as compared with the case where the detector is not provided.

According to the transfer apparatus according to claim 4, the twist of the drive system of the image holder can be efficiently released as compared with the case where the second peripheral speed is lower than the peripheral speed of the image holder. can.

According to the transfer device according to claim 5, the twist of the drive system of the image holder can be released.

According to the transfer apparatus according to claim 6, the driving of the image holder can be maintained.

It is a schematic block diagram of the image forming apparatus as one Embodiment of this invention. It is a figure which shows the drive system of a photoconductor drum. It is a graph which shows the example of the rotational vibration generated in a photoconductor drum. It is a figure which roughly represented the rotational drive of a transfer belt and a transfer roller when a paper rushes into a transfer area. It is a graph which shows the reduction example of the rotational vibration generated in a photoconductor drum. It is a graph which shows the relationship between the magnitude of a temporary acceleration, and the effect of suppressing rotational vibration. It is a graph which shows the relationship between the magnitude of a temporary acceleration and the image quality.

Hereinafter, embodiments of the present invention will be described.

FIG. 1 is a schematic configuration diagram of an image forming apparatus as an embodiment of the present invention.

The image forming apparatus 1 is a so-called direct transfer type monochrome printer.

The image forming apparatus 1 includes a photoconductor drum 10. The photoconductor drum 10 is rotatably supported by the drum support frame 10A, and is driven by the photoconductor motor 16 to rotate in the direction of arrow A. A charger 11, an exposure device 12, and a developer 13 are provided around the photoconductor drum 10. Then, a toner image is formed on the surface of the photoconductor drum 10 through each process of charging by the charger 11, exposure by the exposure device 12, and development by the developing device 13, and the toner image is displayed on the photoconductor drum 10. Be retained.

Here, the exposure device 12 exposes the photoconductor drum 10 according to the image data sent from the outside of the image forming apparatus 1, and the image represented by the image data is formed on the photoconductor drum 10 as a toner image. In order to ensure the accuracy of such exposure, the photoconductor drum 10 is driven by the photoconductor motor 16 at a stable rotation speed. In order to realize such a stable rotation speed, the photoconductor motor 16 is supplied with electric power by constant current control. Since the photoconductor motor 16 drives the photoconductor drum 10 by receiving electric power under constant current control, the drive of the photoconductor drum 10 is stable even when the external force on the photoconductor drum 10 changes. There is. The photoconductor drum 10 corresponds to an example of an image holder according to the present invention, and a combination of a charger 11, an exposure device 12, and a developer 13 corresponds to an example of a forming device according to the present invention.

On the other hand, paper P (so-called cut paper), which is a kind of recording material, is conveyed in the direction of arrow X by a paper carrier (not shown), and a transfer region T sandwiched between the photoconductor drum 10 and a transfer device 20 described later is formed. pass. Then, the toner image on the photoconductor drum 10 is transferred onto the paper P while passing through the transfer region T. The image forming apparatus 1 of the present embodiment is an apparatus capable of supporting a plurality of types of paper P, and it is assumed that the type of paper P supplied to the image forming apparatus 1 is input in advance by an input operating means (not shown). ..

The edge of the paper P conveyed to the transfer region T is detected by the paper edge detection sensor 42. The paper edge detection sensor 42 is, for example, an optical sensor or a contact sensor, and detects the passage of the front edge and the rear edge of the paper. The paper edge detection sensor 42 corresponds to an example of the detector according to the present invention.

The remaining toner on the photoconductor drum 10 after the toner image is transferred in the transfer region T is removed from the photoconductor drum 10 by the cleaner 14.

The paper P to which the toner image has been transferred in the transfer region T is further conveyed in the direction of the arrow Y and sent to the fixing device 30. The fixing device 30 includes a heating roller 31 that rotates in the direction of arrow D and a pressure roller 32 that rotates in the direction of arrow E. The heating roller 31 and the pressure roller 32 are in contact with each other to form a fixing region S. The paper P traveling in the direction of the arrow Y rushes into the fixing region S, and is heated and pressurized while passing through the fixing region S, and the toner image on the paper P is fixed on the paper P. As a result of this fixing, an image consisting of a fixing toner image is formed on the paper P. The paper P on which the image is formed is sent out to the outside of the image forming apparatus 1 by a paper transmitter (not shown).

The transfer device 20 corresponds to an embodiment of the transfer device of the present invention, and includes a transfer roller 21, a pressure welding roller 22, a peeling roller 23, and an endless transfer belt 24 hung around the rollers. There is. The transfer roller 21, the pressure welding roller 22, and the release roller 23 are rotatably supported by the transfer device support frame 20A.

The transfer roller 21 is driven by the transfer motor 26 and rotates in the direction of arrow B to drive the transfer belt 24. The transfer belt 24 is a resin belt having low elasticity, and is circulated and moved in the direction of arrow C by receiving a driving force by the transfer roller 21. The transfer belt 24 corresponds to an example of the transfer member referred to in the present invention.

The transfer roller 21 is located upstream of the rotation center axis of the photoconductor drum 10 in the paper traveling direction, and presses the transfer belt 24 against the photoconductor drum 10 from the inside of the transfer belt 24. The transfer roller 21 defines the upstream edge of the transfer region T in which the photoconductor drum 10 and the transfer belt 24 are in contact with each other.

Further, the pressure contact roller 22 is located on the downstream side in the paper traveling direction with respect to the rotation center axis of the photoconductor drum 10, and pushes the transfer belt 24 toward the photoconductor drum 10 from the inside of the transfer belt 24. The pressure welding roller 22 defines the downstream edge of the transfer region T.

Further, the peeling roller 23 is a roller having a smaller diameter than the transfer roller 21, and the paper is placed on the transfer belt 24 by sharply bending the traveling direction of the transfer belt 24 by the peeling roller 23. The tip of P is peeled off from the transfer belt 24. The paper P peeled off from the transfer belt 24 is guided by the guide member 41 and proceeds in the direction of the arrow Y, and is sent to the fixing device 30 as described above.

Further, the transfer device 20 includes a cleaner 25. Toner and other stains adhering to the transfer belt 24 are removed from the transfer belt 24 by the cleaner 25.

The transfer roller 21 is connected to a power source (not shown), and a transfer bias is applied to the transfer roller 21 from the power source. Due to the action of the transfer bias, the toner image on the photoconductor drum 10 is transferred onto the paper P while the paper P passes through the transfer region T.

The transfer roller 21 has a rotating shaft 211, and the rotating shaft 211 is rotatably supported by a transfer device support frame 20A that supports the entire transfer device 20.

The transfer device 20 is provided with a control unit 29 having a CPU as a calculation unit and a RAM or ROM as a storage unit 29A, and the control unit 29 controls the drive of the transfer roller 21 by the transfer motor 26. Further, the load of the transfer motor 26 is also detected by monitoring the drive current supplied to the transfer motor 26. The control unit 29 stores the detected load in the storage unit 29A. Then, the control unit 29 controls the drive of the transfer motor 26 based on the detected load, so that the drive of the transfer belt 24 is adjusted so as to be driven according to the peripheral speed of the photoconductor drum 10. .. The combination of the control unit 29 and the transfer motor 26 corresponds to an example of the drive according to the present invention.

Here, the rotational drive of the photoconductor drum 10 and the rotational drive of the transfer roller 21 and the transfer belt 24 described above will be described in more detail. In the present embodiment, the photoconductor drum 10, the transfer roller 21, and the transfer belt 24 are driven by drive systems that are independent of each other.

FIG. 2 is a diagram showing a drive system of the photoconductor drum 10.

The photoconductor drum 10 is connected to one end of the drive shaft 19 via a coupling 18. The coupling 18 stably transmits the drive to the photoconductor drum 10 when the drive shaft 19 is rotating in the forward direction relative to the photoconductor drum 10, but the drive shaft 19 is the photoconductor. If the drum 10 is rotated in the opposite direction to the drum 10, the coupling 18 is disconnected and the transmission of the driving force is cut off, which may cause the driving to become unstable. This coupling 18 corresponds to an example of a coupler according to the present invention.

A flywheel 17 that stabilizes the rotation of the drive shaft 19 is fixed to the other end of the drive shaft 19 on the opposite side of the photoconductor drum 10.

The source of the driving force for driving the photoconductor drum 10 is the photoconductor motor 16 as described above. The driving force of the photoconductor motor 16 is transmitted to the drive shaft 19 via a plurality of drive gears. That is, the driving force is directly transmitted from the photoconductor motor 16 to the first gear 55 fixed to the rotating shaft of the photoconductor motor 16. The first gear 55 meshes with the second gear 53 of the intermediate gear 54 in which the second gear 53 and the third gear are coaxially fixed, and transmits a driving force to the intermediate gear 54. The third gear 52 of the intermediate gear 54 meshes with the fourth gear 51 fixed to the drive shaft 19, and the driving force is transmitted from the intermediate gear 54 to the drive shaft 19.

The transfer belt 24 that circulates and moves by bringing the peripheral surface into contact with the photoconductor drum 10 driven by such a drive system so that the speed of the peripheral surface is slightly slower than the peripheral surface speed of the photoconductor drum 10. It is driven by the control unit 29 and the transfer motor 26. By driving the transfer belt 24 in this way, the relative rotation direction of the drive shaft 19 with respect to the photoconductor drum 10 is stabilized in the forward direction, and the rotational drive of the photoconductor drum 10 is stabilized.

When the peripheral speed of the transfer belt 24 is kept slightly slower than the peripheral speed of the photoconductor drum 10 in this way, the rigidity of the drive system of the photoconductor drum 10 shown in FIG. 2 is different. Twist (that is, distortion in the direction in which the shaft that transmits the driving force is twisted) accumulates in a portion weaker than the portion of. When the paper P rushes into the transfer region T in such a state where the twist is accumulated, the twist is instantly released, and the force of the release may cause rotational vibration in the photoconductor drum 10.

FIG. 3 is a graph showing an example of rotational vibration generated in the photoconductor drum 10.

The horizontal axis of FIG. 3 represents the passage of time, and the vertical axis of FIG. 3 represents the difference (arbitrary unit) between the rotation of the photoconductor motor 16 and the rotation of the photoconductor drum 10.

The graph shown in FIG. 3 shows the change in the rotation difference when (the front end) of the paper P rushes into the transfer region T at time t0, and the paper P is stored in the transfer region T with the above-mentioned twist of the drive system accumulated. It can be seen that when (the front end) rushes in, the rotation difference increases sharply at time t0. This rotation difference greatly swings between the plus side and the minus side, and the photoconductor drum 10 oscillates with respect to a stable rotation speed. When such rotational vibration occurs, the accuracy of exposure to the photoconductor drum 10 deteriorates, and the image density on the image decreases at a position corresponding to the moment when the rotational vibration occurs, as compared with other places. Streaks (image defects) occur.

In the image forming apparatus 1 of the present embodiment shown in FIG. 1, in order to suppress the occurrence of such streaks (image defects), the transfer belt 24 (and the transfer roller 21) when the paper P enters the transfer region T The rotary drive is devised as described below.

FIG. 4 is a diagram schematically showing the rotational drive of the transfer belt 24 (and the transfer roller 21) when the paper P enters the transfer region T.

The horizontal axis of FIG. 4 represents the passage of time, and FIG. 4 shows the graph G1 showing the detection signal of the paper edge detection sensor 42 (see FIG. 1) and the rotation speed of the transfer roller 21 for driving the transfer belt 24. The graph G2 showing the above is shown.

When the front edge of the paper P is detected by the paper edge detection sensor 42 as shown by the rising edge of the detection signal graph G1, the transfer roller 21 The rotation speed is increased. Since the rotation speed is increased by detecting the front edge of the paper P, it becomes easy to control the speed increase timing.

The rotation speed of the transfer roller 21 is increased so that the peripheral speed of the transfer belt 24 exceeds the peripheral speed of the photoconductor drum 10. By such an increase in speed, the twist of the drive system of the photoconductor drum 10 described above is released, and the generation of streaks (image defects) is suppressed.

The rotation speed of the transfer roller 21 is returned to the original rotation speed before the front end of the paper P enters the transfer region (transfer nip) T, as shown by the fall in the rotation speed graph G2. If the speed-increasing state continues even after the front end of the paper P has entered the transfer region T, the paper P may be wound around the photoconductor drum 10, so that the front end of the paper P is in the transfer region T in the speed-increasing state. It is terminated before it rushes. That is, the speed-increasing state of the transfer roller 21 is a temporary state. Specifically, the transfer roller 21 is accelerated only in a section of about 30 mm before the front end of the paper P enters the transfer region T. As the conveying speed of the paper P, a speed of 460 mm / s, 535 mm / s, or 600 mm / s is typically used, so that the time interval for increasing the speed is about 0.05 seconds to 0.06 seconds.

When the rear edge of the paper P is detected by the paper edge detection sensor 42 as shown by the falling edge of the detection signal graph G1, the rotation speed is not particularly changed. This is because the twist of the drive system is not accumulated while the paper P is present in the transfer region T, and there is no particular problem even if the rear end of the paper P enters the transfer region T.

The duration of the speed-increasing state is preset to a duration longer than the time required for the twist of the drive system to be released. Therefore, the paper edge detection sensor 42 is arranged at a position away from the transfer region T by a distance such that such a duration can be obtained before the front edge of the paper P enters the transfer region T. The specific distance from the transfer region T is derived in consideration of the magnitude of the speed increase, the transport speed of the paper P, and the like.

Further, even after the front edge of the paper P has entered the transfer region T, if it is within the range up to the margin of the image, for example, the control in which the speed increasing state is terminated after that can be adopted. That is, the drive according to the present invention stops the temporary acceleration to the second peripheral speed before the image forming region of the recording material enters the transfer region, and causes the transfer member to have the first peripheral speed. It may be returned to. By ending the speed increase before the image transfer to the recording material is started, image defects due to the speed change during the image transfer are avoided. Further, it is considered that even if the paper P enters the transfer region, the paper P is unlikely to be wound around the photoconductor drum 10 if it is about the margin portion.

Further, the above-mentioned acceleration of the transfer roller 21 is terminated before the coupling 18 shown in FIG. 2 is disengaged, and the magnitude of the acceleration is also suppressed to a size that maintains the coupling of the coupling 18. There is. As a result, the transmission of the driving force by the coupling 18 is maintained.

The temporary acceleration action described above will be further described by showing specific data.

FIG. 5 is a graph showing an example of reduction of rotational vibration generated in the photoconductor drum 10.

The horizontal axis of FIG. 5 represents the passage of time, and the vertical axis of FIG. 5 represents the difference (arbitrary unit) between the rotation of the photoconductor motor 16 and the rotation of the photoconductor drum 10.

The graph shown in FIG. 5 shows the case where the paper P (front end) rushes into the transfer region T at time t0 after the temporary acceleration as shown in FIG. 4 is executed by the transfer roller 21 (and the transfer belt 24). It shows the change of the rotation difference in.

Since the paper P (front end) has entered the transfer region T after the above-mentioned twist of the drive system is released, it can be seen that the rotation difference does not change in particular before and after the time t0. Further, it can be seen that the fluctuation width of the rotation difference is small when compared with the graph shown in FIG. Therefore, the accuracy of exposure to the photoconductor drum 10 is maintained, and streaks (image defects) in the image are suppressed.

FIG. 6 is a graph showing the relationship between the magnitude of the temporary acceleration and the suppressing action of rotational vibration.

The horizontal axis of FIG. 6 represents the amount of acceleration of the transfer roller 21 in the temporary acceleration, and the vertical axis shows the peak-to-peak width in the graph as shown in FIGS. 3 and 5 changing at time t0. The amount is expressed as a ratio around time t0.

As can be seen from the graph shown in FIG. 6, when the speed is not increased before the front edge of the paper P rushes into the transfer region T, the peak-to-peak width becomes 1.6 times before and after the rush time t0. The number is increasing, and rotational vibration is occurring. On the other hand, when the speed is temporarily increased before the entry time t0, the peak-to-peak width before and after the entry time t0 is increased as the acceleration amount is increased up to a certain amount of acceleration. It can be seen that the ratio of the above decreases, and the ratio may decrease to less than 1.2 times. Therefore, it was confirmed from the data that the rotational vibration in the photoconductor drum 10 was suppressed by the temporary acceleration of the transfer roller 21 before the front end of the paper P rushed into the transfer region T.

FIG. 7 is a graph showing the relationship between the magnitude of the temporary acceleration and the image quality.

The horizontal axis of FIG. 7 represents the speed increase amount of the transfer roller 21 in the temporary speed increase, and the vertical axis represents the image brightness of the exposed portion at the time when the front end of the paper P enters the transfer region T and the image. It shows the difference from the image brightness of the exposed part in the middle of the area. The image brightness is measured by using a test image in which a density difference (streak-like image defect) is likely to occur due to the rotational vibration of the photoconductor drum 10.

As can be seen from the graph shown in FIG. 7, as the amount of speed increase in the temporary speed increase increases, the difference in image brightness decreases up to a certain amount of speed increase. That is, it was confirmed from the data that the density difference (streak-like image defect) was suppressed by the temporary acceleration of the transfer roller 21 before the front end of the paper P rushed into the transfer region T.

In the above description, a roll-shaped photoconductor drum is shown as an example of the image-retaining body according to the present invention, but the image-retaining body according to the present invention may be a belt-shaped, for example, an intermediate transfer body.

Further, in the above description, a belt-shaped member is exemplified as the transfer member referred to in the present invention, but the transfer member referred to in the present invention may be a roll-shaped member.

Further, in the above description, a monochrome printer is exemplified as an embodiment of the image forming apparatus of the present invention, but the image forming apparatus of the present invention may be a color printer, or may be a copying machine, a facsimile, or a multifunction device. There may be.

Further, in the above description, a direct transfer type apparatus is exemplified as an embodiment of the image forming apparatus of the present invention, but in the image forming apparatus of the present invention, an image is transferred from a photoconductor to a recording material via an intermediate transfer body. It may be an indirect transfer type device to be used. In the case of such an indirect transfer type apparatus, the transfer apparatus of the present invention may be applied to a place where an image is first transferred from a photoconductor to an intermediate transfer body, or may be applied to a recording material from the intermediate transfer body. It may be applied to the place where the image is secondarily transferred.

Further, the present invention has been invented for the purpose of solving the problems described in the "problems to be solved by the invention" column, but the configuration of the present invention is other in a form that does not solve this problems. Diversion to the intended purpose is not hindered, and a form in which the configuration of the present invention is diverted in this way is also an embodiment of the present invention.

1 ... Image forming device (printer), 10 ... Photoreceptor, 11 ... Charger, 12 ... Exposed device,
13 ... Developer, 16 ... Photoreceptor motor, 20 ... Transfer device, 21 ... Transfer roller,
24 ... Transfer belt, 26 ... Transfer motor, 29 ... Control unit, 30 ... Fixing device,
42 …… Paper edge detection sensor

Claims (7)

An image holder that at least circulates around the peripheral surface and holds an image on the peripheral surface,
A transfer member in which at least the peripheral surface circulates and passes through a transfer region between the image holder and the image holder so that the image on the image holder is transferred to the recording material.
The transfer member is driven, and during the transfer of an image to the recording material, the peripheral speed of the transfer member is controlled to a first peripheral speed lower than the peripheral speed of the image holder, and the recording material controls the peripheral speed. Before entering the transfer region, a drive that temporarily increases the peripheral speed of the transfer member to a second peripheral speed higher than the first peripheral speed,
A transfer device characterized by being equipped with. The drive stops the temporary acceleration to the second peripheral speed before the recording material enters the transfer region, and returns the transfer member to the first peripheral speed. The transfer device according to claim 1, wherein the transfer device is provided. A detector for detecting the tip of the recording material toward the transfer region before entering the transfer region is provided.
The claim is characterized in that the drive increases the speed of the transfer member from the first peripheral speed to the second peripheral speed, triggered by the detection of the tip by the detector. The transfer device according to 1 or 2. Any one of claims 1 to 3, wherein the driver increases the second peripheral speed to a peripheral speed higher than the peripheral speed of the image holder. The transfer device according to. The drive causes a temporary increase in speed from the first peripheral speed to the second peripheral speed in the drive system of the image holder as it is driven at the first peripheral speed. The transfer device according to any one of claims 1 to 4, wherein the twisting continues for a period of time longer than the time at which the twist is released. The image holder is driven by a driving force transmitted via a coupler.
1. The driver claims that the temporary acceleration from the first peripheral speed to the second peripheral speed is stopped in less than a time when the coupler is disengaged. 5. The transfer apparatus according to any one of 5. An image holder that at least circulates around the peripheral surface and holds an image on the peripheral surface,
A former that forms an image on the peripheral surface of the image holder,
A transfer member in which at least the peripheral surface circulates and passes through a transfer region between the image holder and the image holder so that the image on the image holder is transferred to the recording material.
The transfer member is driven, and during the transfer of an image to the recording material, the peripheral speed of the transfer member is controlled to a first peripheral speed lower than the peripheral speed of the image holder, and the recording material controls the peripheral speed. Before entering the transfer region, a drive that temporarily increases the peripheral speed of the transfer member to a second peripheral speed higher than the first peripheral speed,
An image forming apparatus characterized by being provided with.

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