JP2007240612A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of surely performing image correction even when the peripheral length of an intermediate transfer body is short, and suitable for miniaturization. <P>SOLUTION: Only a toner image for printing is formed on a region, where deformation caused by contact with tensioning and laying means on the intermediate transfer body shows such an extent that the image correction is not appropriately performed if a toner image for controlling is formed on the deformed region, but the toner image for controlling is not primarily transferred to that region. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an intermediate transfer member.

  In a conventional image forming apparatus using an electrophotographic system, a method is proposed in which a toner image is formed on an image carrier and transferred to a transfer material via an intermediate transfer member to obtain an image. Hereinafter, an image forming apparatus having an intermediate transfer member will be described with reference to FIG. 1 which is a schematic diagram showing a main configuration. Here, the exploration member 33 is not provided.

  In such an image forming apparatus, the intermediate transfer member 17, which is a flexible endless belt made of synthetic resin, is stretched and rotated by each stretching means of the drive roller 11, the tension roller 12, and the secondary transfer roller 6 a. . When the intermediate transfer member 17 is not in operation, the intermediate transfer member 17 remains stationary while being stretched by the stretching unit. However, when this state continues for a long time, deformation occurs in a region in contact with the stretching unit.

  In addition, it is conventionally known to correct image forming conditions before starting to form a print image for transfer to a recording material such as a sheet material or an OHP film. This is performed when the environmental conditions including temperature and humidity are assumed to have changed, such as immediately after the image forming apparatus is turned on or when a predetermined time has elapsed since the previous image forming operation. This is done to keep it constant.

  As one of the correction methods, a control toner image is formed on the intermediate transfer member 17, and the density of the control toner image is checked from the reflected light intensity by a density detection sensor 32 including a light emitting portion and a light receiving portion, for example. There are methods for correcting conditions. Here, the correction of the image forming conditions specifically corrects the toner image forming conditions such as the charging bias voltage, the developing bias voltage, the primary and secondary transfer bias voltages, and the toner supply amount.

  As shown in FIG. 2A, the density detection sensor 32 is set so that it can be reliably detected by the light receiving unit when light is applied to a toner image formed in a region where the intermediate transfer member is not deformed. Yes. Therefore, when the control toner image Tp is formed in the deformed area as shown in FIG. 2B, the reflected light is not detected correctly, and the image forming condition correction does not function correctly.

Means for avoiding such problems have been conventionally proposed (see, for example, Patent Document 1). For example, Japanese Patent Application Laid-Open No. 2004-205757 discloses that a home position is provided on the intermediate transfer member, and this is controlled so as to stop near the roller that generates the largest wave. Since the largest wave is generated in the vicinity of the home position, if the control toner image is formed while avoiding this region, malfunction of image correction can be avoided.
Japanese Patent Laying-Open No. 2004-205757 (page 11, FIG. 1)

  In recent years, there has been an increasing demand for miniaturization of image forming apparatuses, and it is necessary to shorten the peripheral length of the intermediate transfer member as the apparatus is miniaturized. The problem at this time is the formation of a control toner image. As shown in FIG. 3B, the control toner image includes a plurality of control toner images formed in the rotation direction of the intermediate transfer member 17, and if the peripheral length of the intermediate transfer member is short, There is a possibility that a deformed portion of the transfer body and a part of the plurality of control toner images overlap.

  As described above, the image correction is usually performed immediately after the power is turned on or after a predetermined time has elapsed since the previous image formation. Therefore, once an inappropriate image formation condition is corrected, the next image formation condition is corrected. All the print images formed so far will deteriorate.

  By the way, when the image forming conditions are properly corrected, an output image (print image) obtained by secondary transfer transfer onto the transfer material even if some deformation occurs in the intermediate transfer body 17. The quality of the product does not deteriorate so much. The present invention pays attention to this point, and provides an image forming apparatus suitable for downsizing by reliably correcting the image forming conditions even if the circumference of the intermediate transfer member is short in order to solve the above-described problems. With the goal.

  In order to achieve the above object, the present invention provides an image carrier, a developing unit that visualizes a latent image formed on the image carrier as a toner image, and a plurality of stretching units that are stretched and rotated. An intermediate transfer member that is a possible endless belt, a primary transfer member that primarily transfers a toner image from the image carrier to the intermediate transfer member, and a secondary transfer that secondary transfer of the toner image from the intermediate transfer member to a transfer material An image forming apparatus comprising: a member; and a control unit configured to detect a density of the control toner image on the intermediate transfer member and control a toner image forming condition according to the detection result, wherein the rotation direction of the intermediate transfer member For each of the plurality of regions divided into two, the time that is in contact with the stretching means and stationary and the time that is stationary without contacting with the stretching means are integrated, and based on the integrated value First transfer the control toner image to the specified area. , For printing a toner image is an image forming apparatus, characterized by also primarily transferred to the specific area.

  Still another object of the present invention for achieving the above object is to provide an image carrier, a developing unit that visualizes a latent image formed on the image carrier as a toner image, and a plurality of stretching units. An intermediate transfer member that is a rotatable endless belt, a primary transfer member that primarily transfers a toner image from the image carrier to the intermediate transfer member, and a secondary transfer of the toner image from the intermediate transfer member to a transfer material. An image forming apparatus comprising: a secondary transfer member; and a control unit that detects a density of a control toner image on an intermediate transfer member and controls a toner image forming condition according to a detection result. And a sensing means for detecting the deformation state of the intermediate transfer member due to contact with the toner, and the control toner image is not primarily transferred to the specific area specified based on the detection result by the sensing means. The toner image is also primarily transferred to the specific area. An image forming apparatus, characterized by.

  Still another object of the present invention for achieving the above object is to provide an image carrier, a developing unit that visualizes a latent image formed on the image carrier as a toner image, and a plurality of stretching units. An intermediate transfer member that is a rotatable endless belt, a primary transfer member that primarily transfers a toner image from the image carrier to the intermediate transfer member, and a secondary transfer of the toner image from the intermediate transfer member to a transfer material. An image forming apparatus comprising: a secondary transfer member; and a control unit that detects the density of the control toner image on the intermediate transfer member and controls the toner image forming condition according to the detection result. Above, the control toner image is not primarily transferred to the specific area that is in contact with the stretching means and is stationary immediately before the start of the formation of the control toner image. An image forming apparatus that performs primary transfer.

  The control toner image is formed avoiding the deformation area of the intermediate transfer member, and the print image is also formed in the deformation area. Therefore, even when the intermediate transfer member is short, image correction can be performed reliably, and the image forming apparatus can be downsized. The effect is also suitable for.

Example 1
An image forming apparatus according to an embodiment of the present invention will be described with reference to FIG. (Here, it is assumed that there is no exploration member 33.)
The image forming apparatus according to this embodiment is an electrophotographic image forming apparatus, and a charging unit, an exposing unit, a developing unit, a cleaner, and the like are disposed around a photosensitive drum 1 that is an image carrier. The toner image formed on the photosensitive drum 1 is primarily transferred onto the intermediate transfer member 17 and then secondarily transferred from the intermediate transfer member 17 to a recording material such as paper or an OHP sheet.

  In order to form a full-color image, the developing device 4 includes developing devices 4a, 4b, 4c, and 4d that respectively hold yellow, magenta, cyan, and black toners. Each developing device rotates and moves to a position facing the photosensitive drum 1 as necessary to visualize the electrostatic latent image as a toner image.

  The photosensitive drum 1 is rotated clockwise around a support shaft 1a by a driving source (not shown) in the direction indicated by an arrow, and has a conductive substrate such as aluminum and a photoconductive layer formed on the outer periphery thereof. A charging roller 2 serving as a charging unit is a roller member that rotates in contact with the photosensitive drum 1 and charges the surface of the photosensitive drum 1 uniformly.

  An exposure unit 9 is disposed downstream of the charging roller 2 in the rotation direction of the photosensitive drum 1 and scans and exposes the photosensitive drum 1 based on image information. In the exposed area on the surface of the photosensitive drum 1, the electrostatic latent image is formed by losing the charge.

  A developing device 4 is provided downstream of the exposure means 9. Each of the developing devices 4a to 4d held by the developing device 4 is rotated and moved to a position facing the photosensitive drum 1 during the developing operation, and is selected according to the color information of the electrostatic latent image to be developed. In this embodiment, the developing device is of a magnetic brush type. By applying a developing bias voltage, the toner adhering to the carrier constituting the ears of the magnetic brush adheres to the area where the charge has been lost in the previous exposure process. A toner image is formed on the photosensitive drum 1.

  A primary transfer roller 5 is disposed downstream of the developing device 4 and below the photosensitive drum 1. The primary transfer roller 5 is pressed against the photosensitive drum 1 with an intermediate transfer member 17 sandwiched by an urging means (not shown) to form a primary transfer nip. A primary transfer bias voltage is applied to the primary transfer roller 5, and toner is primarily transferred from the surface of the photosensitive drum 1 to the surface of the intermediate transfer member 17 due to a potential difference with the photosensitive drum 1.

  On the surface of the photosensitive drum 1 after the primary transfer, there are residual toner that has not been transferred to the intermediate transfer body 17 and deposits such as paper dust due to the transfer material. A cleaner 3 is provided on the downstream side of the photosensitive drum 1 with respect to the primary transfer nip so as to come into contact with the photosensitive drum 1 and collect deposits. The deposits are removed before the next image forming process.

  In the case of forming an image composed of a plurality of colors, the above-described steps are repeated by changing the developing device used for development, and the respective color toner images are superimposed on the intermediate transfer member 17 with registration. The toner image thus obtained is secondarily transferred to a transfer material supplied from the paper feed cassette 10 at an appropriate timing in the secondary transfer unit 6. In the secondary transfer portion, as in the primary transfer portion, a secondary transfer bias is applied to the secondary transfer roller 6b, and the secondary transfer is subjected to secondary transfer to the transfer material under the action of an electric field. The transfer material carrying the toner image is conveyed to the fixing unit 8 and heated and pressed to obtain a permanent image. Further, after the secondary transfer, the intermediate transfer member 17 collects the toner remaining on the surface by the intermediate transfer cleaner 7 and then stops at a random position through a post-rotation.

  Next, correction of image forming conditions generally performed in the image forming apparatus will be described.

  If the image obtained from the image forming apparatus is not adjusted, the quality varies depending on the environmental conditions during image formation such as temperature and humidity. Therefore, before the image formation operation for printing, when the power is turned on or when a predetermined time has elapsed since the previous image formation, the image formation conditions are corrected so as to maintain a constant image quality regardless of environmental conditions. To do. Thereafter, the above-described printing image forming process is executed.

  For the correction of the image forming conditions, a monochromatic control toner image having a uniform density as shown in FIGS. 3A and 3B is formed on the intermediate transfer member 17. Among these, the one composed of one control toner image as shown in FIG. 3A is used for rough correction, and the control toner image having a different density as shown in FIG. Those arranged in the above are suitable for correction of intermediate gradations. Note that the shape of the control toner image is not limited to that shown in the drawing, and may be any value as long as there is no inconvenience in reading.

  As a specific image forming condition correcting operation, first, a control toner image is formed on the intermediate transfer member 17. In the image forming apparatus, a density detection sensor 32 having a light emitting element and a light receiving element is disposed opposite to the image forming surface side of the intermediate transfer body 17 to detect the reflected light intensity of the control toner image. . The image forming apparatus stores a value corresponding to the output value obtained from the density detection sensor 32 when a control toner image having a certain density is detected, and stores the actual output value and the image forming apparatus during the correction operation. The comparison is made with the standard output value. When the actual output value from the density detection sensor 32 is different from the reference value stored in the image forming apparatus, the toner such as the charging bias, the developing bias, the primary transfer bias, and the toner supply amount corresponding to the difference. Correct the image forming conditions.

  The intermediate transfer member 17 is stretched so as not to be loosened by the stretching means of the secondary transfer roller 6a, the driving roller 11, and the tension roller 12. Further, position detection marks 30 are provided at two locations on the surface of the intermediate transfer member 17 on the side in contact with the stretching means. The position detection mark 30 is detected by a position detection sensor 31 disposed in a space surrounded by the intermediate transfer body 17, and registration is performed. Further, the position of the intermediate transfer member 17 in the rotation direction is managed by being divided into a plurality of regions as shown in FIG. 4, for example, which region of the intermediate transfer member 17 is stretched based on the detection timing of the position detection mark 30. It can be checked whether it is in contact with the mounting means.

  In this embodiment, because of the tendency of deformation, the case where the diameter of the member stretching the intermediate transfer member 17 is 70 mm or less and the angle α shown in FIG. 5 is 160 ° or less is targeted. In addition, the rotation direction contact area between the stretching means and the intermediate transfer member 17 is defined as all the areas that are actually in contact with the stretching means.

  The image forming apparatus according to the present embodiment has a control unit (not shown), and is divided into an A area, a B area,..., A P area in the circumferential direction (rotation direction) of the intermediate transfer member 17 as shown in FIG. The time Ta in which each area is in contact with the stretching means and the time Tb in which the area is stationary without contact are measured and integrated for each area.

  If the region of the intermediate transfer member 17 that is stationary in contact with the stretching means remains stationary for a long time, the shape of the stretching means is maintained even after the contact state with the stretching means is released. The deformation according to the occurs. This deformation is not permanent and will eventually recover if left untouched. Therefore, in the present invention, the above-described Ta and Tb are integrated for each region of the intermediate transfer member 17, the difference or ratio is calculated, and when the calculated value exceeds a predetermined threshold value, Control is performed so that a control toner image is not formed in the region. The threshold value to be set is determined at the design stage according to the material, thickness, tension, tensioning means diameter, and the like of the intermediate transfer member 17, and the deformation generated in the intermediate transfer member 17 is controlled in the deformation region. A value at which an appropriate image forming condition cannot be obtained when a toner image is formed is set as a threshold value.

  As described above, when the control toner image is formed in the deformed area of the intermediate transfer member 17, correction is performed based on an inappropriate output value of the density detection sensor 32, and therefore, until the next image forming condition correction. All the print images formed in the above deteriorate. However, if the image forming condition correction is properly performed, even if an image for printing is formed on the deformed area on the intermediate transfer body 17 and this is secondarily transferred to the transfer material, Since the image has a screen wider than the deformation area, the obtained output image is not significantly deteriorated. Therefore, in this embodiment, in the area of the intermediate transfer body 17 where the calculated value obtained from the above Ta and Tb exceeds the threshold, the deformation is such that an appropriate image forming condition cannot be obtained when the control toner image is formed. Assuming that it has occurred, control is performed so that a control toner image is not formed. On the other hand, even in the printing operation immediately after the image forming condition correction operation is completed, the printing toner image is also formed in the region where the control toner image has not been transferred.

  As described above, the image forming condition can be surely corrected even when the intermediate transfer member 17 is deformed. At the same time, the printing image can be short so that the intermediate transfer member can be used effectively. The effect which contributes to size reduction is acquired.

(Example 2)
Another embodiment according to the present invention will be described. In this embodiment, when the image forming conditions are corrected from the stationary state of the intermediate transfer member 17, the region of the intermediate transfer member 17 that has been stationary in contact with the stretching means immediately before the image correction is performed is deformed. As a result, the control toner image is not formed.

The outline of the image forming apparatus according to the present embodiment is shown in FIG. 1, and the intermediate transfer member 17 after the post-rotation is controlled to stop at random based on the information of the position detection sensor 31. Does not stop at position. (Here, it is assumed that the exploration member 33 does not exist.)
In this example, the control unit divides the intermediate transfer member 17 into a plurality of regions in the rotation direction and manages the positional information of each region. Therefore, the intermediate transfer member starts to rotate for the image forming condition correction operation. An area that is in contact with the stretching means and is stationary until immediately before is recognized. Therefore, the control means does not form a control toner image in an area where the intermediate transfer body is in contact with the stretching means and remains stationary until the intermediate transfer member starts rotating for the correction operation of the image forming conditions. On the other hand, also in the printing operation immediately after the image forming condition correction operation is completed, the printing toner image is also formed in the region where the control toner image is not formed.

  According to this configuration, it is not necessary to add up the time during which the respective regions divided in the rotation direction of the intermediate transfer body 17 are in contact with the stretching unit or are not in contact with each other. The load is reduced, and the same effect as in the first embodiment can be obtained with simpler control.

(Example 3)
Still another embodiment according to the present invention will be described with reference to FIG. Also in this embodiment, the post-rotation intermediate transfer body 17 is controlled to stop at random based on the information of the position detection sensor 31, and does not stop at the same position continuously.

  As shown in FIG. 1, the needle-like exploration member 33 of the sensing means is arranged so as to be in contact with the intermediate transfer member 17 whenever the deformation of the intermediate transfer member 17 is examined. The exploration member is movable in the axial direction, and the displacement from the reference value is based on the contact position with the intermediate transfer body 17 when the intermediate transfer body 17 is not deformed due to the stationary contact with the stretching member. Is detected.

  As in the previous embodiment, it is possible to determine in advance how much deformation will cause image correction to be impossible. Therefore, the output value obtained from the search member 33 corresponding thereto is set as a threshold value. The region on the intermediate transfer member 17 that has obtained an output indicating a displacement exceeding the threshold is considered to have undergone deformation that does not allow image correction to be performed properly when a control toner image is formed. No control toner image is formed, and only a print image is formed.

  Here, the occurrence of deformation is detected by means that contacts the intermediate transfer member 17, but a non-contact exploration method in which deformation is checked by a sensor having a light emitting part and a light receiving part, for example, may be used. Of course.

  According to the configuration disclosed in the present embodiment, since the deformation of the intermediate transfer member 17 is directly examined, the degree of deformation is more reliably than the method of assuming that there is deformation from the contact time with the stretching means. Can be grasped. In particular, in the case of an optical sensor, the density detection sensor 32 can be used as it is, and a simpler configuration can be obtained. Further, the use of the contact means has an advantage that contamination of the optical system does not become a problem.

  In this way, whether or not the deformation of the intermediate transfer member 17 can withstand image correction is determined by comparing the output value of the exploration member 33 with a threshold value by a control means (not shown), and in an area exceeding the threshold value. Does not form a control toner image, and the print image is also formed in an area exceeding the threshold. As a result, the same effect as in the first embodiment can be obtained.

Example 4
Another embodiment according to the present invention will be described. Description of matters common to the first embodiment will be omitted.

  First, let us consider a case where the control toner images formed side by side in the rotation direction of the intermediate transfer member 17 are longer than the region of the intermediate transfer member 17 where the deformation has occurred, and overlapping cannot be avoided.

  A case where the L region is deformed on the intermediate transfer member 17 divided into a plurality of regions in the rotation direction will be described with reference to FIG. In general, two adjacent control toner images are formed with a fixed interval a, but there are cases where a is 0, that is, the control toner images are in contact with each other.

  As shown in FIG. 6A, there are cases where two images overlap in the deformation area. In this embodiment, when the length b in the rotation direction of the intermediate transfer member 17 overlapping the deformation region of the control toner image β is considered, if a is shorter than b, the control is performed as shown in FIG. Since the toner image β cannot be shifted to the upstream side of the L region with respect to the rotation direction of the intermediate transfer member, the control toner image after the control toner image β is downstream of the L region as shown in FIG. Will shift to the side. On the other hand, when a is longer than b, not only the shift in the downstream direction but also the control toner image β is deformed by changing the interval between the control toner images α and β as shown in FIG. 6B. It is also possible to shift to the upstream side of the region.

  Further, if the length c in the rotational direction of the intermediate transfer member 17 that overlaps the deformation area of the control toner image γ is shorter than the distance a between the control toner image δ and the control toner image δ and the subsequent control toner images δ, It is only necessary to change the interval between the control toner images γ and δ without shifting the toner image. When c is longer than a, the control toner image after the control toner image γ is shifted downstream as a whole. Of course, when the interval between the toner images is changed, the control toner images may be shifted so that they contact each other. Further, it is not essential to provide an interval between the control toner image and the deformation area, and the deformation area may be in contact with the boundary as long as the image correction is not affected.

  In the case where only the control toner image β overlaps the deformation area as shown in FIG. 6D, as in the case where the two control toner images overlap the deformation area, if a is longer than b, It can be shifted to either downstream side, but otherwise it can be shifted only downstream.

  Further, consider a case where three or more adjacent control toner images, such as control toner images β, γ, and δ, overlap with the deformation region. Even in this case, when a is longer than b, the most upstream control toner image overlapping the deformation area can be shifted to either the upstream side or the downstream side. Otherwise, the area overlapping the deformation area Are all shifted to the downstream side.

  The interval between the control toner images can be changed not only immediately before and after the deformation area, but also between the control toner images overlapping with the deformation area, or adjacent to the control toner image overlapping with the deformation area. It is also possible to arbitrarily set the interval between the control toner images formed in the non-deformation region before and after the deformation region even if the interval is other than the above. In this case, even if a is shorter than b, it is possible to shift to the upstream side by shortening the interval between the control toner images formed upstream of the deformation region. Furthermore, the control toner image overlapping with the deformation area can be formed not only simply in the upstream or downstream direction but also in the uppermost stream or the most downstream of the series of control toner images by changing the order. .

  In addition, of course, even if a plurality of deformation regions are generated, it is possible to avoid the deformation regions by the above-described control.

  As described above, by appropriately changing the interval between the control toner images, the control toner image is not formed in the deformed area, and the print image is formed in the intermediate transfer member rotation direction area including the deformation area. The effect similar to Example 1 is acquired by forming.

Sectional view of an image forming apparatus according to the present invention and the prior art Schematic diagram showing abnormal toner image density detection due to deformation of intermediate transfer member Example of toner image for control FIG. 3 is a development view illustrating an example of the division of the rotation direction of the intermediate transfer member in the present invention. The figure which shows the definition of the contact area with the roller of this invention FIG. 6 is a diagram illustrating movement of a control toner image according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging roller 3 Photosensitive drum cleaner 4 Developing apparatus 4a, 4b, 4c, 4d Developer 5 Primary transfer roller 6 Secondary transfer part 6a, 6b Secondary transfer roller 7 Intermediate transfer cleaner 8 Fixing part 8a Fixing roller 8b Addition Pressure roller 9 Exposure means 10 Paper feed cassette 11 Drive roller 12 Tension roller 17 Intermediate transfer body 30 Position detection mark 31 Position detection sensor 32 Concentration detection sensor 33 Search member P Transfer material

Claims (4)

An image carrier;
Developing means for visualizing the latent image formed on the image carrier as a toner image;
An intermediate transfer member that is an endless belt that is stretched around a plurality of stretching means and can be rotated;
A primary transfer member for primarily transferring a toner image from the image carrier to the intermediate transfer member;
A secondary transfer member for secondary transfer of a toner image from the intermediate transfer member to a transfer material;
Control means for detecting the density of the control toner image on the intermediate transfer member and controlling the toner image forming conditions according to the detection result;
An image forming apparatus having
For each of the plurality of regions divided in the rotation direction of the intermediate transfer member, the time that is in contact with the stretching means and the time that is stationary without contacting the stretching means is integrated. ,
The control toner image is not primarily transferred to the specific area specified based on the integrated value,
An image forming apparatus, wherein a toner image for printing is primarily transferred also to the specific area. An image carrier;
Developing means for visualizing the latent image formed on the image carrier as a toner image;
An intermediate transfer member that is an endless belt that is stretched around a plurality of stretching means and can be rotated;
A primary transfer member for primarily transferring a toner image from the image carrier to the intermediate transfer member;
A secondary transfer member for secondary transfer of a toner image from the intermediate transfer member to a transfer material;
Control means for detecting the density of the control toner image on the intermediate transfer member and controlling the toner image forming conditions according to the detection result;
An image forming apparatus having
Sensing means for detecting the deformation state of the intermediate transfer member due to contact with the stretching means;
The control toner image is not primarily transferred to the specific area specified based on the detection result by the sensing means,
An image forming apparatus, wherein a toner image for printing is primarily transferred also to the specific area. An image carrier;
Developing means for visualizing the latent image formed on the image carrier as a toner image;
An intermediate transfer member that is an endless belt that is stretched around a plurality of stretching means and can be rotated;
A primary transfer member for primarily transferring a toner image from the image carrier to the intermediate transfer member;
A secondary transfer member for secondary transfer of a toner image from the intermediate transfer member to a transfer material;
Control means for detecting the density of the control toner image on the intermediate transfer member and controlling the toner image forming conditions according to the detection result;
An image forming apparatus having
On the intermediate transfer body, the control toner image is not primarily transferred to the specific area that is in contact with the stretching means and immediately before the start of the formation of the control toner image.
An image forming apparatus, wherein a toner image for printing is primarily transferred also to the specific area. An image forming apparatus that primarily transfers a plurality of control toner images in a rotation direction of an intermediate transfer member over a section longer than the specific region, wherein a part of the plurality of control toner images is transferred with respect to the rotation direction. The image forming apparatus according to claim 1, wherein the remaining portions of the plurality of control toner images are primarily transferred downstream from the specific region.

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