JP3644471B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that forms a color image in accordance with an image forming process such as an electrophotographic process, and more specifically, primary transfer is performed by sequentially superimposing a plurality of single-color visible images formed on an image carrier on an intermediate transfer member. Further, the present invention relates to an image forming apparatus in which a multicolor image obtained by superimposing the monochromatic visible images is secondarily transferred from an intermediate transfer member to a recording material to form a color image on the recording material.
[0002]
[Prior art]
A conventional electrophotographic color image forming apparatus is configured, for example, as shown in FIG. In this color image forming apparatus, for example, a drum-shaped photoconductor 10 (image carrier) is charged and exposed to form an electrostatic latent image on the photoconductor 10, and the electrostatic latent image is developed into the developing device 20. Developed with The developing device 20 includes developing units 20a, 20b, 20c, and 20d that perform development with black toner (K), yellow toner (Y), magenta toner (M), and cyan toner (C), respectively.
Further, a transfer belt 30 to which toner images of respective colors formed on the photoconductor 10 are transferred is provided adjacent to the photoconductor 10. The transfer belt 30 is wound around rollers 31, 32, and 33 so as to rotate in a predetermined direction (the direction of the arrow in the figure). An intermediate transfer roller 35 is provided so as to face the photoreceptor 10 with the transfer belt 30 interposed therebetween. Further, a transfer roller 40 is provided to face the roller 33 with the transfer belt 30 in between, and a cleaning device 45 is installed at a predetermined position. The transfer roller 40 and the cleaning device 45 are supported by a mechanism that can contact and separate from the transfer belt 30. The transfer roller 40 is integrally provided with a transfer roller cleaner 41 for removing the toner attached to the transfer roller 40.
[0003]
In the color image forming apparatus having the above-described structure, for example, an operation command for forming a plurality of the same color image (for example, a plurality of color copy commands) or an operation command for forming a plurality of different color images (for example, a plurality of color images) In the state where the transfer roller 40 and the cleaning device 45 are separated from the transfer belt 30, each color toner image developed by each developing unit is sequentially superimposed on the transfer belt 30 by the intermediate transfer roller 35. A plurality of (for example, two) multicolor images I (1) and I (2) are formed on the transfer belt 30. When the transfer of the final toner image to the first multicolor image I (1) is completed, the transfer roller 40 is driven to contact the transfer belt 30 and is supplied between the transfer roller 40 and the transfer belt 30. The leading multicolor image I (1) is transferred to the recording sheet. Similarly, the second multicolor image I (2) formed on the transfer belt 30 is also transferred onto the next recording sheet supplied between the transfer roller 40 and the transfer belt 30.
[0004]
As described above, when the transfer of the leading multicolor image I (1) to the recording sheet is completed, the leading end of the region where the leading multicolor image I (1) is formed before the installation position of the cleaning device 45 is reached. In addition, the cleaning device 45 is driven so as to contact the transfer belt 30. As a result, the residual toner after the transfer of the leading multicolor image I (1) is reliably removed from the leading end portion of the image. Thereafter, by maintaining this state, residual toner after the transfer of the second multicolor image I (2) is also removed by the cleaning device 45.
[0005]
By the way, in the color image forming apparatus as described above, in order to stabilize the color tone reproducibility of the color image, it is necessary to confirm whether the density of the toner image of each color is appropriately controlled. Therefore, for example, as described in JP-A-3-174560, when forming a toner image of each color corresponding to a color image to be originally formed, a density detection pattern is formed with the same color toner, and the density It has been proposed to control the density of each toner image in the next image forming cycle based on the detected density.
[0006]
[Problems to be solved by the invention]
It is generally considered that this density detection pattern is formed before the toner image corresponding to the original color image is formed. In such a case, as shown in FIG. 11, the density detection pattern Ic formed with each color toner is formed in a region before the leading edge of the leading multicolor image I (1) on the transfer belt 30.
[0007]
In such a case, the cleaning device 45 is brought into contact with the transfer belt 30 at the tip A of the density detection pattern Ic from the viewpoint of efficiently removing residual toner and density detection pattern after the transfer of the multicolor image on the transfer belt 30. It is preferable to control the contact / separation of the cleaning device 45 so that the cleaning device 45 is separated from the transfer belt 30 at the rear end B of the final multicolor image I (2). Further, since there is a possibility that the transfer belt 30 is vibrated when the cleaning device 45 is brought into contact with the transfer belt 30, ideally, when the cleaning device 45 comes into contact with the transfer belt 30, the final many The formation of the color image I (2) is preferably completed (primary transfer of the final toner image is completed).
[0008]
In order to satisfy the above conditions, if the distance between the rear end B of the final multicolor image I (2) and the front end A of the density detection pattern Ic is narrow, the operating speed of the cleaning device 45 must be increased. In addition, since the transfer belt 30 vibrates correspondingly, it is preferable to increase the operating time of the cleaning device 45 and suppress the vibration of the transfer belt 30 by widening the distance A to B as much as possible.
At this time, if the distance between A and B is too wide, the transfer belt 30 must be lengthened, and image productivity is reduced (decrease in image forming speed). Although it is conceivable to make the density detection pattern Ic as small as possible, if it is made too small, the density detection accuracy using the density detection pattern Ic is lowered.
Furthermore, it is conceivable that the primary transfer position where the photosensitive member 10 and the intermediate transfer roller 35 face each other is as close as possible to the cleaning device 45. However, the periphery of the photoconductor 10 has a mechanism (developer, etc.) for performing an electrophotographic process. In order to arrange each mechanism around the photoconductor 10 so as not to interfere with the cleaning device 45, a primary is used. The transfer position and the cleaning device 45 cannot be made extremely close to each other.
[0009]
Therefore, an object of the present invention is to reduce image disturbance caused by vibration when the cleaning device is brought into contact with the transfer belt, while taking into account efficient removal of residues, without taking the above measures. It is an object of the present invention to provide an image forming apparatus capable of forming a control image (for example, a density detection pattern) at a position where it can be moved.
[0010]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems, the present invention as described in claim 1 includes a plurality of different colors formed on an image carrier 1 according to an image forming process such as an electrophotographic process or an electrostatic recording process, as shown in FIG. An intermediate transfer body 2 on which a visible image is superimposed and transferred to form a multicolor image I, and transfer means 3 for electrostatically transferring the multicolor image I formed on the intermediate transfer body 2 to a recording material P And a plurality of multicolor images I formed on the intermediate transfer body 2 are transferred to the recording material P in the order in which they are formed, and are transferred onto the intermediate transfer body 2. In the image forming apparatus having the cleaning device 4 for removing the residue, the first multicolor image I (() with the plurality of multicolor images I (1) to I (n) formed on the intermediate transfer body 2 is formed. 1) from the leading edge A to the trailing edge B of the final multicolor image I (n)And on the region of the intermediate transfer body 2 that includes the multicolor images I (1) to I (n).It is configured to set the formation area S of the control image IcIn addition, the control image Ic is not formed on the region of the intermediate transfer body 2 before the front end A of the leading multicolor image I (1).
[0011]
In such an image forming apparatus, in the intermediate transfer body 2, the control image Ic is not formed in the area before the tip A of the leading multicolor image I (1). This eliminates the need for the cleaning device 4 to contact the intermediate transfer member 2 before the leading end A of the leading multicolor image I (1). That is, the distance between the position at which the cleaning device 4 is to be brought into contact with the intermediate transfer body 2 and the rear end B of the final multicolor image I (n) is wider than the conventional image because there is no control image Ic. Therefore, the operation time of the cleaning device 4 when the cleaning device 4 is brought into contact with the intermediate transfer member 2 can be effectively earned.
[0012]
After the leading multicolor image I (1) is transferred to the recording material P, the cleaning device 4 is brought into contact with the intermediate transfer body 2 at the tip A of the formation region of the leading multicolor image I (1). The residue after the transfer of each multicolor image is removed by the cleaning device 4. Then, the control image Ic formed in the predetermined region S of the intermediate transfer body 2 can be removed until the residue at the rear end B of the formation region of the final multicolor image I (n) is removed. .
[0013]
The above control imageIcIs used for detecting the density of each visible image, and includes images used for various controls such as detecting various positions.
Further, the intermediate transfer member 2 may be belt-shaped or drum-shaped.
Control image without increasing the width of the intermediate transfer member 2IcFormation areaSIn the present invention, as described in claim 2, the control image formation region can be set to a region sandwiched between two multicolor images. In this case, the two multi-color images are the first multi-color image I (1) formed on the intermediate transfer member 2 as described in claim 3, or as described in claim 4. Intermediate transfer member2The final multicolor image formed onI (n)It can comprise so that it may contain.
[0014]
  Furthermore, in the image forming apparatus as described above, from the viewpoint of eliminating the need to accurately form the control image Ic in a narrow area sandwiched between multicolor images, the present invention provides the following. The formation area S of the control image Ic can be set to an area other than the area sandwiched between two multicolor images.
  Furthermore, when the formation area S of the control image Ic is set between two multicolor images, as many portions of the control image Ic as possible are transferred to the intermediate transfer body 2 after the multicolor image is transferred to the recording material P. It can be removed and removed at once by the cleaning device 4KiFrom the viewpoint of achieving the above, according to the present invention, as described in claim 6, the transfer means 3 applies an electrostatic electric field to the formation area S of the control image Ic to the formation area S of the multicolor image. It can comprise so that it may have an electric field control means which controls so that the electrostatic attraction force concerning the transfer may fall rather than an electrostatic electric field.
[0015]
In such an image forming apparatus, a multicolor image is transferred from the intermediate transfer body 2 to the recording material P by a predetermined electrostatic electric field from the transfer means 3.IIs transcribed. Also, a control image set between two multicolor imagesIcFormation areaSThen, the transfer means 3 controls the electrostatic electric field so that the electrostatic attraction force related to the transfer is reduced. The result is a multicolor imageIControl image than the transfer rate ofIcThe transfer rate from the intermediate transfer body 2 is reduced. That is, the control imageIcThe amount remaining on the intermediate transfer body 2 increases.
[0016]
Furthermore, from the viewpoint of preventing the control image Ic from being transferred from the intermediate transfer body 2 to the transfer means 3 itself, the present invention provides the electric field control means as described in claim 7. Ic formation regionSIt can be configured to block the electrostatic field with respect to.
In such an image forming apparatus, the formation region of the control image IcSThen, since an electrostatic field that generates an electrostatic attraction force is not generated, the control image Ic remains as it is as the intermediate transfer member.2And is removed from the intermediate transfer body 2 by the cleaning device 4.
From the viewpoint of more reliably preventing the control image Ic from being transferred from the intermediate transfer body 2 to the transfer means 3 itself, the present invention provides the electric field control means as described in claim 8. Ic formation regionSThe polarity of the electrostatic field with respect to the multicolor imageIFormation areaSIt can be configured to control the polarity of the electrostatic field with respect to the reverse of the polarity.
[0017]
In such an image forming apparatus, the formation region of the control image IcSA multicolor imageIAn electrostatic field having a characteristic opposite to that of the electrostatic field used for transfer of the image is generated. Even if a mechanical action (contact with the recording material P or the like) acts on the control image Ic, the control image Ic is transferred from the intermediate transfer body 2 by the electrostatic attraction force from the electrostatic field having the opposite polarity. 3 is positively prevented from being transferred to itself.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a diagram schematically illustrating a configuration example of an image forming apparatus according to an embodiment of the present invention.
In FIG. 2, this image forming apparatus (for example, a copying machine) is similar to the conventional apparatus shown in FIG. 11 in order to form a color image by an electrophotographic process, for example, a drum-shaped photosensitive material made of an organic photoconductive material. A body 10 and a charger 11 disposed around the body 10, an optical system 12 for guiding an exposure light beam to the surface of the photoreceptor 10, and a developing device 20 are provided. The developing device 20 includes developing units 20a, 20b, 20c, and 20d that perform development with black toner (K), yellow toner (Y), magenta toner (M), and cyan toner (C), respectively.
[0019]
Similarly to the conventional image forming apparatus shown in FIG. 11, a transfer belt 30 (intermediate transfer member) that is wound around rollers 31, 32, and 33 and rotates in a predetermined direction (in the direction of the arrow) is a photosensitive member 10. It is provided adjacent to. An intermediate transfer roller 35 (for primary transfer) is disposed opposite the photoconductor 10 with the transfer belt 30 interposed therebetween, and a transfer roller 40 (for secondary transfer) is opposed to the roller 33 to the transfer belt 30. It is arranged so as to be able to contact and separate. Further, a cleaning device 45 is provided at a predetermined position upstream of the transfer belt 30 in the rotation direction (in the direction of the arrow) so as to be able to contact with and separate from the transfer belt 30.
[0020]
A transfer roller cleaner 41 is integrally provided on the transfer roller 40, and these are integrally configured to be driven toward and away from the transfer belt 30. With the transfer roller 40 in contact with the transfer belt 30, for example, as shown in FIG. 3, the recording sheet P is supplied between the transfer roller 40 and the transfer belt 30 via a guide 42. Yes. A sensor 50 for optically detecting the density of the image formation control pattern (density detection pattern) is installed at a predetermined position downstream of the rotation position of the transfer belt 30 from the installation position of the photoconductor 10.
[0021]
The detailed configuration of the transfer mechanism associated with the transfer roller 40 is, for example, as shown in FIG. In FIG. 4, the roller 33 around which the transfer belt 30 is wound is grounded, and an electric field forming unit 46 is connected to the transfer roller 40. The electric field forming unit 46 applies a predetermined potential to the transfer roller 40 to form an electrostatic electric field between the transfer roller 40 and the roller 33. As described above, the recording sheet P whose supply timing is adjusted by the registration roller 43 is transferred to the transfer roller 40 via the guide 42 as described above in a state where the electrostatic electric field is formed between the transfer roller 40 and the roller 33. When supplied to the transfer belt 30, a multicolor image (multiple image of toner) formed on the transfer belt 30 as described later is transferred onto the recording sheet P by the electrostatic attraction force by the electrostatic electric field. The
[0022]
In the image forming apparatus as described above, for example, when an operation command is issued to form a plurality of the same color image or a plurality of different color images, the transfer roller 40 and the cleaning device 45 are separated from the transfer belt 30. Thus, an image forming process is executed. That is, the photoconductor 10 uniformly charged by the charger 11 is modulated based on the light beam modulated based on the image data, then the light beam modulated according to the image formation control pattern, and further modulated based on the image data. The light beam is sequentially exposed to form an electrostatic latent image corresponding to each. Then, the electrostatic latent image is developed with a predetermined developing unit (for example, for black toner), and a toner image of an image to be originally formed and an image formation control pattern with the same color toner are formed on the photoreceptor 10. .
[0023]
These toner image and image formation control pattern are sequentially transferred to the transfer belt 30 that rotates in synchronization with the rotation of the photosensitive member 10 by the intermediate transfer roller 35. As a result, a single color toner image is formed on the transfer belt 30 and an image formation control pattern Ic of the same color toner is formed between the single color toner images. Thereafter, similarly, toner images of other colors (yellow, magenta, cyan) are sequentially formed on the toner image on the transfer belt 30, and the image formation control patterns of the other color toners are not overlapped each time. It is formed in a region between the multiple toner images on the transfer belt 30.
[0024]
As a result of the above process, as shown in FIG. 2, a multicolor image I (1) formed by superimposing four color toner images, an image formation control pattern Ic by each color toner, and the next multicolor image I (2) are sequentially obtained. It is formed on the transfer belt 30. As described above, in the process of forming the multicolor image and the image shape control pattern Ic on the transfer belt 30, the density of the image formation control pattern Ic of each color toner is detected by the sensor 50, and the detected data is a control system (not shown). ). This detection data is used to control the development characteristics (the amount of toner supplied to each development unit, etc.) in the next image forming process, and stabilizes the color tone reproducibility.
[0025]
Immediately before the leading edge of the first multicolor image I (1) reaches the transfer position (at this time, the last toner image of the final multicolor image I (2) is not completely overlaid). 40 is brought into contact with the transfer belt 30, and the recording sheet P whose timing is adjusted by the registration roller 43 is supplied between the transfer roller 40 and the transfer belt 30. As a result, the leading multicolor image I (1) is transferred to the recording sheet P. The cleaning device 45 is brought into contact with the transfer belt 30 immediately before the leading end of the formation region of the leading multicolor image I (1) reaches the installation position of the cleaning device 45. As a result, the residual toner after the transfer of the multicolor image I (1) is removed by the cleaning device 45. In addition, immediately before the leading edge of the final multicolor image I (2) reaches the transfer position, the next recording sheet P whose timing has been adjusted by the registration roller 43 is supplied between the transfer roller 40 and the transfer belt 30. The As a result, the final multicolor image I (2) is transferred to the next recording sheet P.
[0026]
Thereafter, the residual toner after the transfer of the image formation control pattern Ic and the final multicolor image I (2) is sequentially removed from the transfer belt 30 by the cleaning device 45.
When the cleaning device 45 is brought into contact with the transfer belt 30, the intermediate transfer position and the installation position of the cleaning device 45 are arranged so that the last toner image of the final multicolor image I (2) is completely overlaid. Is set. In this case, since there is no image formation control pattern to be removed in the area before the first multicolor image I (1), the contact position of the cleaning device 45 on the transfer belt 30 and the final multicolor image I (2). The distance from the rear end can be set relatively wide without extending the transfer belt 30. Accordingly, the intermediate transfer position and the installation position of the cleaning device 45 can be set as described above without particularly reducing the efficiency of image formation.
With such a setting, the image quality of the final multicolor image I (2) is reliably prevented from being deteriorated by the vibration when the cleaning device 45 is brought into contact with the transfer belt 30.
[0027]
For example, as shown in FIG. 5A, when an image formation control pattern is formed on the transfer belt 30 in an area between two multicolor images (image formation areas), an electric field connected to the transfer roller 40 is formed. The unit 46 generates an electric field from the transfer roller 40 with the characteristics shown in FIG. In other words, an electric field (constant current +26 μA) is generated in the multicolor image formation region so that the multicolor image is sufficiently transferred to the recording sheet P, and an electric field having a reverse polarity (in the image formation control pattern formation region ( Constant current -26 μA) is generated.
By controlling the transfer electric field as described above, the multicolor image is reliably transferred to the recording sheet P, and the image formation control pattern is reliably prevented from being transferred to the transfer roller 40.
[0028]
The electric field forming unit 46 can also generate an electric field from the transfer roller 40 with the characteristics shown in FIG. In this case, the electric field is blocked (constant current 0 A) in the image formation control pattern formation region. Such a control of the transfer electric field can prevent the image formation control pattern from being transferred to the transfer roller 40. However, in this case, the electrostatic attraction force does not act on the image formation control pattern, and the toner of the image formation control pattern may adhere to the transfer roller 40 due to mechanical contact with the transfer roller 40. The toner adhering to the transfer roller 40 is removed by the transfer roller cleaner 41.
[0029]
Furthermore, the electric field forming unit 46 can generate an electric field from the transfer roller 40 with the characteristics shown in FIG. In this case, the electric field is reduced in the formation region of the image formation control pattern (+13 μA). By controlling the transfer electric field, a part of the toner of the image formation control pattern is transferred to the transfer roller 40 and the other part remains on the transfer belt 30. Therefore, the toner of the image formation control pattern is removed by the cleaning device 45 and the transfer roller cleaner 41.
The image forming control patterns Ic (K), Ic (Y), Ic (M), and Ic (C) of the toners of black (K), yellow (Y), magenta (M), and cyan (C) are transferred belts. 30 can be formed as follows.
[0030]
For example, as shown in FIG. 6, in the region R between the leading end of the leading multicolor image I (1) and the trailing end of the final multicolor image I (n), the leading and next multicolor image I The image formation control patterns Ic (K) and Ic are formed in the region between (1) and I (2) and the regions between the final and preceding multicolor images I (n−1) and I (n). (Y), Ic (M), and Ic (C) are formed so as to be arranged in a direction perpendicular to the rotation direction of the transfer belt 30.
[0031]
Further, as shown in FIG. 7, the area between the head and the next multicolor image I (1), I (2), and the last and the previous multicolor images I (n−1), I (n The image formation control patterns Ic (K), Ic (M) and the image formation control patterns Ic (Y), Ic (C) are arranged in the rotation direction of the transfer belt 30 in each region between Are formed in a direction perpendicular to the rotation direction of the transfer belt 30.
Further, as shown in FIG. 8, the image formation control patterns Ic (K) and Ic (M) are transferred to the area between the head and the next multicolor image I (1), I (2). The image formation control patterns Ic (Y) and Ic (C) are arranged in a region perpendicular to the moving direction, and in a region between the final and preceding multicolor images I (n−1) and I (n). The transfer belt 30 is arranged in a direction perpendicular to the rotation direction of the transfer belt 30.
Furthermore, the image formation control pattern does not necessarily have to be formed in a region sandwiched between two multicolor images. For example, as shown in FIG. 9, each image formation control pattern Ic (K), Ic (Y), Ic (M), Ic (C) is the first multicolor image I (1) and the last multicolor image I. It can also be arranged in the non-image area on the side of (n) in the rotation direction of the transfer belt 30. In this case, a dedicated cleaning device 47 for removing the image formation control pattern from the transfer belt 30 is provided.
[0032]
In the above example, as described above, the intermediate transfer position and the cleaning device are arranged so that the last toner image of the final multicolor image is completely overlaid when the cleaning device 45 contacts the transfer belt 30. Although 45 installation positions are set, the present invention is not limited to this. For example, as shown in FIG. 10, there may be an untransferred portion in the final toner image of the final multicolor image I (2) when the cleaning device 45 contacts the transfer belt 30. However, since the image formation control pattern is not formed in the area before the first multicolor image I (1), the contact position of the cleaning device 45 with the transfer belt 30 and the final multicolor image I (2) are accordingly increased. ) The distance from the rear end can be increased. Therefore, it is possible to gain some operating time for the cleaning device 45 when the cleaning device 45 contacts the transfer belt 30. Thereby, the image quality disturbance generated in the final multicolor image I (2) due to the vibration generated when the cleaning device 45 contacts the transfer belt 30 can be minimized.
[0033]
【The invention's effect】
  As described above, according to the invention described in each claim, the interval between the leading end of the first multicolor image and the trailing end of the final multicolor image on the intermediate transfer member.On the side of the intermediate transfer body containing the multicolor imageSet the control image formation areaDo not form a control image on the area of the intermediate transfer body before the leading edge of the first multicolor image.Therefore, the area where the cleaning device is disposed in contact with the intermediate transfer member can be set larger than the conventional one from the rear end of the final multicolor image to the front end of the first multicolor image.
  Therefore, when the cleaning device is placed in contact with the intermediate transfer member, the operation speed of the cleaning device can be reduced, and the intermediate transfer member generated when the cleaning device is placed in contact with the intermediate transfer member. Vibration can be reduced, and image disturbance caused by vibration can be reduced as much as possible.
[Brief description of the drawings]
FIG. 1 is a block diagram for explaining the principle of the present invention.
FIG. 2 is a schematic explanatory diagram of an image forming apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a state of a recording sheet supplied between a transfer drum and a transfer belt.
FIG. 4 is a diagram showing details of a transfer mechanism.
FIGS. 5A to 5D are diagrams illustrating an example of control of a transfer electric field.
FIG. 6 is a diagram illustrating an example (part 1) of an image formation control pattern formation region;
FIG. 7 is a diagram illustrating an example (part 2) of an image formation control pattern formation region;
FIG. 8 is a diagram illustrating an example (part 3) of an image formation control pattern formation region;
FIG. 9 is a diagram illustrating an example (part 4) of an image formation control pattern formation region;
FIG. 10 is a diagram illustrating another example of the relationship between the intermediate transfer position and the installation position of the cleaning device.
FIG. 11 is a view for explaining a density detection pattern forming position in a conventional image forming apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Intermediate transfer body, 3 ... Transfer means, 4 ... Cleaning device, 10 ... Photoconductor, 11 ... Charger, 12 ... Optical system, 20 ... Developing device, 30 ... Transfer belt, 31, 32 , 33 ... roller, 35 ... intermediate transfer roller, 40 ... transfer roller, 45 ... cleaning device, 46 ... electric field forming unit, 50 ... sensor

Claims (8)

An intermediate transfer body on which a plurality of visible images of different colors formed on an image carrier according to an image forming process are transferred and superimposed to form a multicolor image, and a multicolor image formed on the intermediate transfer body is recorded. A transfer means for electrostatically transferring to the material, and an intermediate transfer member that can be contacted and separated; and a plurality of multicolor images formed on the intermediate transfer member are transferred to the recording material in the order in which they were formed In an image forming apparatus having a cleaning device for removing residues on an intermediate transfer member,
In a state where a plurality of multicolor images are formed on the intermediate transfer member, on the region of the intermediate transfer member including the multicolor image from the leading end of the first multicolor image to the rear end of the final multicolor image An image forming apparatus in which a control image formation area is set in the control image and no control image is formed on the area of the intermediate transfer body before the leading edge of the leading multicolor image . The image forming apparatus according to claim 1.
An image forming apparatus in which the formation area of the control image is set to an area sandwiched between two multicolor images. The image forming apparatus according to claim 2.
The two multicolor images are image forming apparatuses including a leading multicolor image formed on an intermediate transfer member. The image forming apparatus according to claim 2.
The two multicolor images are image forming apparatuses including a final multicolor image formed on an intermediate transfer member. The image forming apparatus according to claim 1.
An image forming apparatus in which the control image formation region is set to a region other than a region sandwiched between two multicolor images. The image forming apparatus according to claim 1,
The transfer unit includes an electric field control unit that controls an electrostatic electric field with respect to a control image forming region so that an electrostatic attraction force related to the transfer is lower than an electrostatic electric field with respect to the multicolor image forming region. apparatus. The image forming apparatus according to claim 6.
The electric field control means is an image forming apparatus configured to block an electrostatic electric field with respect to a control image forming region. The image forming apparatus according to claim 6.
The electric field control means is an image forming apparatus configured to control the polarity of the electrostatic electric field with respect to the control image forming area to be opposite to the polarity of the electrostatic electric field with respect to the multicolor image forming area.

Images