JP2017054090A - Image forming apparatus and control method of image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology to prevent unnecessary performance of cleaning of a transfer roller and prevent a reduction in throughput of printing.SOLUTION: An image forming apparatus comprises: cleaning means that removes a residual toner remaining on a transfer part of the image forming apparatus; determination means that determines whether the residual toner is transferred to a recording medium to be conveyed; and control means that, when the determination means determines that the residual toner is not transferred to the recording medium to be conveyed, prevents the cleaning means from performing the cleaning.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus and a method for controlling the image forming apparatus.

  An image forming apparatus such as a copying machine or a printer using an electrophotographic system abuts a contact type transfer member such as a transfer roller on a traveling photoconductor, and uses the abutting portion as a transfer site. A sheet (recording medium) such as paper is passed. Next, a toner image formed with a developer charged on the surface of the image carrier in advance is transferred to a sheet, and a transfer bias having a polarity opposite to that of the developer is applied to the transfer member to electrostatically adhere to the image carrier. The developer is transferred onto the sheet.

  In such an image forming apparatus, the size of the sheet to be used and the size of the image to be formed must match, but may not match. When the image size to be formed is larger than the sheet size to be used, when the toner image formed on the photoreceptor is transferred to the sheet, the portion of the toner image that protrudes outside the sheet is transferred onto the transfer roller. It will stick. The toner remaining on the transfer roller stains subsequent sheets.

  Therefore, when the formed image size is different from the sheet size, in order to transfer the toner adhering to the transfer roller to the photoreceptor again, the printing operation is interrupted once, and the transfer roller cleaning is performed to prevent the contamination. Has been proposed. Furthermore, a technique for performing transfer cleaning in accordance with the amount of toner attached to the transfer roller has been proposed (Patent Document 1).

JP-A-6-161309

  However, in the technique described in Patent Document 1, when the formed image size and the sheet size are different, the transfer roller cleaning is performed according to the amount of toner attached to the transfer roller regardless of the subsequent sheet size. . Therefore, even if the subsequent sheet size is a size that is not affected by the toner contamination attached to the transfer roller, for example, a size smaller than the preceding sheet, printing is resumed until the transfer cleaning is completed in order to perform transfer cleaning. Therefore, there is a problem that the throughput of printing is lowered.

  An object of the present invention is to provide a technique that prevents unnecessary transfer cleaning and prevents a decrease in printing throughput.

  According to the present invention, for example, a cleaning unit that cleans residual toner remaining in a transfer portion of an image forming apparatus, and a determination unit that determines whether or not the residual toner is transferred to a transported recording medium. And a control unit that prevents the cleaning unit from performing the cleaning when the determination unit determines that the residual toner is not transferred to the conveyed recording medium. An apparatus is provided.

  According to the present invention, it is possible to prevent unnecessary transfer cleaning and to prevent a decrease in printing throughput.

1 is a block diagram illustrating an image forming apparatus according to an embodiment of the present invention. 1 is a schematic sectional view of an image forming apparatus. (A) is image data, (B) is a preceding sheet, (C) is a remaining image, (D) is a preceding sheet on which a recorded image is formed, and (E) is an explanatory diagram showing the positional relationship of image data with respect to the remaining image. . The flowchart which determines the necessity of cleaning. The flowchart which detects sheet size.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. The present invention will be described by taking an example of an image forming apparatus such as an electrophotographic system, electrostatic recording system, or other copying machine or printer as an embodiment, but is not limited thereto. In this embodiment, a sheet-like paper is assumed as the “recording medium”, but a cloth, a plastic film, or the like may be used.

<Image forming apparatus 1>
FIG. 1 is a block diagram of a control configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 includes the following units related to control. A CPU 100 that controls the overall operation of the image forming apparatus 1. A ROM 110 used for the CPU 100 in which a firmware program for driving the image forming apparatus 1 and a boot program for controlling the firmware program are written. A RAM 120 which is a work area for the CPU 100 and a temporary storage area for various data. An image forming unit 3 that forms an image on a sheet to be described later. A high-pressure control unit 101 for performing image formation. A feeding control unit 102 that controls feeding of a sheet to the image forming unit 3. Various sensor groups 103 arranged in the image forming apparatus 1. A communication unit 104 connected to an external computer terminal device such as a controller CR and the like to exchange print data.

  The controller CR is connected to the image forming apparatus 1 and includes the following units related to control. A CPU 200 that controls the operation of the entire controller CR. A ROM 210 used for the CPU 200 in which a firmware program for driving the controller CR and a boot program for controlling the firmware program are written. A RAM 220 which is a work area for the CPU 200 and a temporary storage area for various data. An image processing unit 201 that processes an image of a display on which a user confirms various setting information of the image forming apparatus 1. An operation unit 202 that allows a user to make various settings of the image forming apparatus 1 and confirm the settings. A communication unit 203 connected to the image forming apparatus 1 to exchange print data.

  FIG. 2 is a schematic cross-sectional view of an image forming apparatus 1 that is an example of the present invention. The image forming apparatus 1 supplies the sheet S to the image forming unit 3 from the sheet supply unit 2 that supplies paper (recording medium, hereinafter referred to as sheet S). Next, the image forming apparatus 1 transfers the toner image onto the sheet S in the image forming unit 3 and fixes the toner image onto the sheet S by the fixing device 5 to form a recorded image.

  The sheet supply unit 2 has a plurality of cassettes 61 and 62 (two in the present embodiment) as recording medium storage units for storing the sheets S, and the cassettes 61 and 62 have the same size, or Different sheets S can be stored. The sheet supply unit 2 is provided with pickup rollers 71 and 72 for picking up the sheets S for each of the cassettes 61 and 62, and feeding the sheets S picked up by the pickup rollers 71 and 72. Rollers 91 and 92 are provided.

  Further, the sheet supply unit 2 has a manual feed unit 10 as a sheet supply unit 2 that can supply sheets to the image forming unit 3 separately from the cassettes 61 and 62. The manual feed unit 10 includes a multi-purpose tray (hereinafter referred to as a manual feed tray) 11 that can manually feed non-standard paper, and a paper feed roller 12 that feeds sheets S from the manual feed tray 11.

  The sheet S fed from the cassettes 61 and 62 is conveyed to the registration roller 15 through the sheet conveyance path 13. Further, the sheet S fed from the manual feed unit 10 is also configured such that the conveyance path joins the conveyance path from the cassettes 61 and 62 side at the merging point 16 and reaches the registration roller 15.

  The registration roller 15 is positioned between the cassettes 61 and 62 and the image forming unit 3 on the sheet S conveyance path. The registration roller 15 is a roller that sends the sheet S conveyed from the sheet supply unit 2 (the cassettes 61 and 62 or the manual feed tray 11) to the image forming unit 3 in synchronization with image formation. The sheet S is positioned at the time of image formation by abutting the leading end of the sheet S with the non-driven registration roller 15. The sheet S is conveyed to the image forming unit 3 by the registration roller 15 being driven to rotate in synchronization with the vertical synchronization signal of the image output from the CPU 100.

  A sheet sensor (hereinafter also referred to as a pre-registration sensor) 30 is disposed on the upstream side of the registration roller 15 in the transport direction of the sheet S and on the transport path between the cassettes 61 and 62. . The sheet sensor 30 is configured so that the light shielding plate shields the photosensor by contacting the sheet S, and detects that the sheet S is present at the position. The sheet S is positioned immediately before the registration roller 15. Whether or not there is is detected. Similarly, a sheet sensor 31 having a similar configuration is also disposed on the conveyance path between the manual feed tray 11 and the junction 16, and whether or not there is a sheet conveyed from the manual feed tray 11 toward the registration roller 15. Is detected. The sheet sensor is not limited to the above form, and a sensor that is not in contact with the sheet S may be employed.

  The image forming unit 3 is disposed on the downstream side of the registration roller 15 and includes a photosensitive drum 20, a laser scanner 21, a transfer roller (transfer body) 22, a cleaning blade (cleaning unit) 23, and the like. The photosensitive drum 20 is scanned with laser light from the laser scanner 21 to form an electrostatic latent image on the surface, and the electrostatic latent image is developed with toner of the developing device 24. The toner image formed on the photosensitive drum 20 is transferred to the sheet S conveyed by the registration roller 15 by applying a bias voltage to the transfer roller 22 (transfer portion). The toner remaining on the photosensitive drum 20 after the transfer is removed by the cleaning blade 23.

  The fixing device 5 is disposed on the downstream side of the image forming unit 3 in the sheet conveying direction, and heats and pressurizes the sheet S on which the unfixed toner image is transferred by the image forming unit 3, thereby forming a toner image on the sheet S. Let it settle. The sheet S discharged from the fixing device 5 is sorted by the flapper 27 and discharged to the discharge trays 23 and 25. In the case of duplex printing, a part of the sheet S is discharged to the discharge tray 23 and then the discharge roller 32. Is returned to the reverse path 26 and returned to the junction 16 of the transport path.

<Control example>
Next, a case where the formed image size is larger than the sheet size fed from the manual feed tray 11 will be described as an example with respect to an embodiment of the present invention. As an example of control in this case, control for determining whether or not cleaning is necessary will be described with reference to FIGS. Normally, when the sheet S is stored in the cassettes 61 and 62 and the sheet size is known in advance, no special problem occurs by controlling to feed the recording paper that matches the image size.

  However, when the sheet size is not known in advance, such as when the sheet S is fed from the manual feed tray 11, the formed image size may not match the sheet size. When the sheet size is larger than the image size to be formed, the image is formed on the sheet without being lost, so that there is no problem of partial loss of the image. However, when the sheet size is smaller than the image size to be formed, only incomplete recording in which a part of the image is lost can be performed on the previously fed sheet (preceding recording medium). In addition, the toner image (residual toner, residual recorded image, residual image) that formed a part of the above-mentioned missing image is directly attached to the transfer roller 22, and is supplied later. As a result, the fed sheet (subsequent recording medium) is soiled.

  Therefore, in the present embodiment, the following processing is performed to avoid contamination of the sheet S that is fed after cleaning. 3A is image data forming a recorded image, FIG. 3B is a preceding sheet, FIG. 3C is a residual image, FIG. 3D is a preceding sheet on which a recorded image is formed, and FIG. E) is an explanatory diagram showing the positional relationship between the residual image and the image data. FIG. 4 is a flowchart for determining whether or not the above-described cleaning is necessary. FIG. 5 is a flowchart for detecting the sheet size of the preceding sheet.

  Referring to FIG. 4, when a printing instruction is given by the user operating operation unit 202, image forming apparatus 1 starts a printing operation for predetermined image data. In S401 of FIG. 4, the CPU 100 develops the image data in the image forming unit 3 to acquire the image size, and the image size A1 (see FIG. 3A) of the recorded image to be formed is determined. As shown in FIG. 3A, when the horizontal direction in the drawing is the main scanning direction and the vertical direction is the sub scanning direction, the size of the image size A1 in the main scanning direction is Ax, and the size in the sub scanning direction is Ay. And The main scanning direction is a direction parallel to the rotation axis of the photosensitive drum 20, and the sub-scanning direction is a direction orthogonal to the rotation axis of the photosensitive drum 20 and the conveyance direction of the sheet S.

  Next, in S402 of FIG. 4, it is determined whether or not there is a residual image generated by a printing operation prior to the current printing operation. As shown in FIG. 3C, the residual image is a toner image (residual recorded image, residual image) A2 remaining on the transfer roller 22 after the recording image is formed on the preceding sheet B1, for example. Show. Such a toner image A2 is formed as follows, for example. A preceding sheet B1 (preceding recording medium) having a size Bx in the main scanning direction and a size By in the sub-scanning direction shown in FIG. 3B with respect to the recording image having the image size A1 shown in FIG. Assume that a sheet is fed from the manual feed tray 11 and a recorded image is recorded on the sheet. In this embodiment, Ax is larger than Bx, and Ay and By are the same size, but the present invention is not limited to this. For example, By may be larger than Ay. In the present embodiment, the case where the image size is larger than the sheet size in the main scanning direction and the image size is equal to or smaller than the sheet size in the sub-scanning direction will be described as an example.

  At this time, the feeding control unit 102 conveys the preceding sheet B1 fed from the manual feed tray 11 into the sheet conveying path, and the image forming unit 3 and the fixing device 5 display an image having an image size A1 with respect to the preceding sheet B1. Form. When the image size A1 (main scanning direction (predetermined direction) width Ax) and the main scanning direction (predetermined direction) width Bx of the preceding sheet B1 are compared, Ax> Bx. Therefore, as shown in FIG. Defects are observed in a part of the recorded image transferred to the sheet B1. At this time, a toner image A2 in which a part of the image size A1 remains is left on the transfer roller 22 as shown in FIG. The toner image A2 includes a region B2 where the toner image does not remain by being formed on the preceding sheet B1 at the image size A1.

  This area B2 can be regarded as the same size as the preceding sheet B1, and is arranged at the central portion in the main scanning direction of the image size A1. Accordingly, the toner image A2 is formed by a toner image excluding the region B2 indicated by the inner width Bx ′ (Bx) with respect to the main scanning direction of the image size A1. Accordingly, the toner in the area between the inner width Bx ′ and A2 remains on the transfer roller 22 (the inner width Bx ′ corresponds to the length of the remaining toner in a predetermined direction). In this embodiment, the width of the region B2 in the sub-scanning direction is set to be the same as the width By of the preceding sheet B1 and the width Ay of the image size A1 in the sub-scanning direction. However, the present invention is not limited to this, and the width By of the preceding sheet B1 may be smaller than the width Ay of the image size A1.

  Referring to FIG. 4 again, the presence or absence of the toner image A2 described above is determined in S402, and if there is no residual image (NO in S402), the process proceeds to S405 described later without performing cleaning described later, and image formation (printing operation) is performed. I do. If the toner image A2 is present in S402 (YES in S402), the inner width Bx ′ of the toner image A2 is compared with the width Ax in the main scanning direction (predetermined direction) of the image size A1 acquired in S401 in S403.

  When the inner width Bx ′ of the toner image A2 is equal to or larger than the width Ax in the main scanning direction of the image size A1 in S403 (NO in S402), the image size A1 is formed in the region B2 of the toner image A2, and thus cleaning is performed. In step S405, which will be described later, image formation is performed. That is, it is considered that the image recorded in the current printing operation is recorded on the sheet even if the toner image A2 remaining on the transfer roller 22 exists. Furthermore, the image to be recorded in the current printing operation does not overlap with the toner image A2 on the transfer roller 22, so that the printing operation can be normally completed without performing cleaning described later. By doing so, it is possible to prevent unnecessary transfer cleaning and to prevent a decrease in printing throughput. An example of the image recorded in the current printing operation is that the image size A1 is formed in a region C formed in the region B2, as shown in FIG. In the example shown in FIG. 3E, the width of the region C in the sub-scanning direction is set to be smaller than the width of the region B2. However, the present invention is not limited to this. The width in the direction may be the same width.

  If the inner width Bx ′ of the toner image A2 is smaller than the width Ax in the main scanning direction of the image size A1 in S403 (YES in S403), the transfer cleaning in S404 is executed. When the inner width Bx ′ of the toner image A2 is smaller than the width Ax of the image size A1, the toner image of the image size A1 protrudes from the remaining area B2 of the toner image A2 in the main scanning direction. That is, the toner image A2 formed on the transfer roller 22 overlaps the image of the image size A1 on the transfer roller 22, and if the printing operation is performed as it is, the sheet becomes dirty. Therefore, the transfer roller 22 is cleaned prior to the printing operation (image formation) in S404. In the present embodiment, cleaning is performed by transferring the toner image remaining on the transfer roller 22 (transfer body) to the photosensitive drum 20 (image carrier) and cleaning the photosensitive drum 20.

  Specifically, when the photosensitive drum 20 is rotated during the cleaning process, the surface thereof is negatively charged by a negative potential applied to a charging brush (not shown). The surface of the photosensitive drum 20 is uniformly exposed with laser light from the laser scanner 21, and the surface potential is lowered. On the other hand, since a negative bias potential is applied to the transfer roller 22, the toner image A2 (toner negatively charged) of the protruding image portion adhering to the transfer roller 22 is a photosensitive drum. Move to 20 surfaces. By performing this process at least one rotation of the transfer roller 22, the cleaning process of the transfer roller 22 is completed. At this time, unnecessary toner transferred to the photosensitive drum 20 is removed by a normal cleaning process of the photosensitive drum 20 by the cleaning blade 23.

  Note that the toner adhesion amount to the transfer roller 22 increases as the area of the remaining toner image increases, and the toner adhesion amount decreases as the protruding area decreases. The cleaning process is performed by rotating the transfer roller 22 at least once. However, when the area of the toner image is large, the rotation time of the transfer roller 22 is lengthened. When the area is small, the transfer roller 22 is transferred. By shortening the rotation time of the roller 22, it is possible to clean efficiently. In this embodiment, the toner image is transferred to the photosensitive drum 20 for cleaning. However, the present invention is not limited to such cleaning. For example, the toner image remaining on the transfer roller 22 may be directly cleaned.

  After completing the cleaning in S403, the CPU 100 performs a printing operation (image formation) in S405 and S406. In step S <b> 405, the CPU 100 feeds the sheet B <b> 1 (for example, see FIG. 3B) on which the recorded image is recorded in the main printing operation into the conveyance path. In S406, the CPU 100 records, for example, image data having an image size A1 shown in FIG. 3A on the sheet B1 (image formation).

<Sheet size detection>
After image formation in S406, the CPU 100 detects the sheet size of the sheet B1 in S407. Here, FIG. 5 shows a specific flowchart of sheet size detection. Since the size in the sub-scanning direction (length in the transport direction) of the sheet B1 cannot be directly measured, the sheet sensor 31 on the transport path disposed on the manual feed tray 11 is used. In S <b> 501, the CPU 100 measures the time during which the leading edge and the trailing edge of the sheet B <b> 1 pass the sheet sensor 31. In S502, the CPU 100 determines the length of the preceding sheet B1 in the conveyance direction (size in the sub scanning direction) from the measured time and the conveyance speed of the preceding sheet B1, and detects the size in the sub scanning direction. .

  Next, the size of the sheet B1 in the main scanning direction is measured using an end thermistor (not shown) disposed in the fixing device 5. The end thermistor is disposed, for example, in a fixing roller (not shown) in the fixing device 5 and can also be used as a sensor for detecting a temperature change in the heated fixing roller. A plurality are arranged at predetermined intervals in the direction. In step S503 in FIG. 5, the sheet B1 on which the toner image is transferred passes through the heated fixing roller, so that the sheets B1 come into contact with each other, and the temperature at the contact point of the fixing roller is lowered. The end thermistor detects the temperature change at this time. From the position of the end thermistor whose temperature has been changed in S504, the axial position of the fixing roller in contact with the sheet B1 can be detected, and the size of the sheet B1 in the main scanning direction can be detected. From the above, the size of the sheet B1 in the main scanning direction and the size in the sub-scanning direction can be detected, and the sheet size detection process ends.

  Note that the sheet size detection is not limited to the above-described form. For example, a line sensor extending in the main scanning direction of the sheet B1 may be disposed in the vicinity of the sheet sensor 31. By doing so, the size in the main scanning direction can be detected together with the detection of the leading and trailing edges of the sheet B1 by the sheet sensor. Therefore, the size of the preceding sheet B1 can be detected before the fixing by the fixing device 5. Further, after the length of the conveyance direction by the sheet sensor 31 is determined, the size of the sheet B1 in the main scanning direction may be estimated from the standard size of the sheet S.

<Remaining judgment>
Referring to FIG. 4 again, in S408, the CPU 100 determines whether the toner image (recorded image) of the recorded image on the sheet B1 remains on the transfer unit (transfer roller 22, transfer body) (residual determination). Process). The transfer unit is not limited to, for example, the transfer roller 22 (transfer body), but is a photosensitive drum 20 (image carrier) on which a toner image of a recorded image is developed, and a contact area between the photosensitive drum 20 and the transfer roller 22. May be included. In S408, the CPU 100 compares the width Ax of the image size A1 in the main scanning direction (predetermined direction) with the width Bx of the sheet B1 in the main scanning direction (predetermined direction). When the width Ax of the image size A1 is equal to or smaller than the width Bx of the sheet B1 (NO in S408), the toner image of the recorded image is all printed on the sheet B1 without loss, and no toner image remains on the transfer roller 22 Therefore, it is determined in step S410 whether there is image data for the next print job.

  If there is next image data (YES in S410), the process proceeds to S401, the size of the image data is acquired, and the printing operation processing from S402 is repeated thereafter. If there is no next image data in S410 (NO in S410), this process is terminated as the end of printing.

  When the width Ax of the image size A1 is larger than the width Bx of the sheet B1 (YES in S408), the toner image A2 except for the area B2 remains on the transfer roller 22 as shown in FIG. Therefore, the CPU 100 stores the width Bx of the sheet B1 as the inner width Bx ′ of the residual image, stores that the residual image exists, and uses it in S402 of the next printing operation. In step S410, it is determined whether there is image data for the next print job. If there is next image data (YES in S410), the process proceeds to S401, the size of the image data is acquired, and the printing operation processing from S402 is repeated thereafter. If there is no next image data in S410 (NO in S410), this process is terminated as the end of printing.

  As described above, according to the image forming apparatus of the present embodiment, the formed image size is compared with the fed sheet size, and the presence or absence of the toner image remaining on the transfer roller is detected. Then, the toner image remaining in the next printing operation is compared with the image size to determine whether or not cleaning is performed. At this time, if the image size is equal to or less than the inner width of the remaining toner image, the toner is transferred to the transfer roller and the toner adhering to the sheet is less likely to be stained, so that cleaning is not performed. By continuing the printing operation in this way, it is possible to prevent unnecessary transfer cleaning and to prevent a reduction in printing throughput. Furthermore, the number of times cleaning is performed can be reduced.

  In the present embodiment, for example, if NO is repeated a plurality of times in S403, the cleaning is not executed indefinitely. Therefore, after the printing operation is completed, the cleaning is not performed for a predetermined time or the predetermined number of printing operations are performed. At this time, the cleaning may be controlled regardless of the determination in S403.

  In this embodiment, whether or not cleaning can be performed is controlled according to the presence or absence of a residual image. However, the present invention can also be applied to cleaning performed when the sheet size changes regardless of the presence or absence of a residual image. In the course of continuous printing, in order to reduce the frictional resistance of the photosensitive drum, the developer is attached to the position of the photosensitive drum where the developer has not adhered for a predetermined time (for example, outside the printing area) and collected (cleaned). It is also possible to apply to processing.

  In addition, the function of the above embodiment is realizable also with the following structures. That is, it is also achieved by supplying a program code for performing the processing of the present embodiment to a system or apparatus, and a computer (or CPU or MPU) of the system or apparatus executing the program code. In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code also realizes the function of the present embodiment.

  Further, the program code for realizing the function of the present embodiment may be executed by one computer (CPU, MPU), or may be executed by a plurality of computers cooperating. Also good. Further, the program code may be executed by a computer, or hardware such as a circuit for realizing the function of the program code may be provided. Alternatively, a part of the program code may be realized by hardware and the remaining part may be executed by a computer. Further, the CPU is not limited to the one that performs all the processing by one CPU, and a plurality of CPUs may perform the processing while appropriately cooperating.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 2 Sheet feeding part, 3 Image forming part, 5 Fixing apparatus, 10 Manual feed part, 11 Manual feed tray, 12 Paper feed roller, 13 Sheet conveyance path, 15 Registration roller, 16 Junction point, 17 Side regulation Plate, 20 Photosensitive drum, 21 Laser scanner, 22 Transfer roller, 23 Paper discharge tray, 25 Paper discharge tray, 26 Reverse path, 27 Flapper, 30 Sheet sensor, 31 Sheet sensor, 31 Paper discharge roller, 61 Cassette 1, 62 Cassette 2, 71 Pickup roller 1, 72 Pickup roller 2, 91 Paper feed roller 1, 92 Paper feed roller 2, 100 CPU, 110 ROM, 120 RAM, 202 Operation unit,

Claims (5)

Cleaning means for cleaning residual toner remaining in the transfer portion of the image forming apparatus;
Determination means for determining whether or not the residual toner is transferred to a recording medium being conveyed;
A control unit that prevents the cleaning unit from performing the cleaning when the determination unit determines that the residual toner is not transferred to the conveyed recording medium;
An image forming apparatus comprising:   When the determination unit determines that the width of the transported recording medium in the predetermined direction is smaller than the length of the residual toner in the predetermined direction, the determination unit applies the residual toner to the transported recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus determines that the image is not transferred. The transfer unit includes at least an image carrier that carries a toner image, and a transfer body that contacts the image carrier,
The image forming apparatus according to claim 1, wherein the determination unit determines whether toner of the toner image remains as residual toner on the transfer body.   The image forming apparatus according to claim 3, wherein the cleaning unit cleans the image carrier by transferring the residual toner remaining on the transfer member to the image carrier. A cleaning step for cleaning the residual toner remaining in the transfer portion of the image forming apparatus by a cleaning means;
A determination step of determining whether or not the residual toner is transferred to a recording medium being conveyed;
If it is determined by the determination step that the residual toner is not transferred to the recording medium being conveyed, a control step in which the cleaning by the cleaning unit is not performed;
An image forming apparatus control method comprising:

Images