JP2010169988A - Image processing apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent misalignment of an image formed on recording material by reducing the variation in transporting speed of the recording material caused when the recording material is thrusted into a rotor that retains an unfixed image. <P>SOLUTION: An absolute value for bias that is applied from a bias generation circuit 110 during a period including the time of contact with a secondary transfer roll 108 is made larger than a value that is suitable for secondary transferring when a toner image formed on a transfer belt 112 is transferred to paper to be transported through a paper transporting passage 103. The bias voltage applied in the secondary transferring exerts a force for making the paper adhere to the secondary transfer roll 108, thereby the restraining force of the secondary transfer roll 108 against the paper is increased by the operation above, the variation in the transporting speed of the paper is prevented, and the misalignment of the image formed on the recording material is prevented. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and a program.

  Patent Document 1 discloses a speed difference between a sheet transport speed and a moving speed of an image carrier for the purpose of avoiding an image position shift (color shift) due to a speed difference between the sheet transport speed and the image carrier speed. And a drive control means for driving and controlling the sheet conveyance drive means and the image carrier drive means so as to reduce the speed difference between them.

JP 2005-91913 A

  An object of the present invention is to reduce fluctuations in the conveyance speed of a recording material that occurs when the recording material enters a rotating body that holds an unfixed image, and to suppress positional deviation of an image formed on the recording material.

  According to the first aspect of the present invention, there is provided a rotating body that holds an unfixed image, and a voltage that controls a voltage applied between the recording material and the rotating body in a state where the recording material is in contact with the rotating body. Control means, wherein the voltage control means applies a first potential difference between the recording material and the rotating body in a first period including a time when the recording material starts to contact the rotating body. And controlling to apply a second potential difference smaller than the first potential difference between the recording material and the rotating body in a second period after the first period. An image forming apparatus.

  According to a second aspect of the present invention, in the first aspect of the invention, the rotation body is controlled to be a first rotation speed in the first period, and the rotation is performed in the second period. It is further characterized by further comprising a rotational speed control means for controlling the body to be at the second rotational speed.

  According to a third aspect of the present invention, in the second aspect of the present invention, the first rotational speed is smaller than the second rotational speed.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, further comprising conveying means for conveying the recording material toward the rotating body, wherein the conveying means is the rotating member. After the recording material comes into contact with the body, the application of the driving force to the recording material is stopped, and control is performed to reduce the rotational speed of the rotating body during a period including the stop time.

  The invention according to claim 5 is a program that is read and executed by a computer, and the recording material and the recording medium are in a first period including a time at which the recording material starts to contact a rotating body that holds an unfixed image. Control is performed to apply a first potential difference between the recording medium and the rotating body, and the second potential is smaller than the first potential difference between the recording material and the rotating body in a second period after the first period. A program for executing control for adding a potential difference of 2.

  According to the first aspect of the present invention, as compared with the case where the invention of the first aspect is not adopted, the change in the conveyance speed of the recording material that occurs when the recording material enters the rotating body that holds the unfixed image. And the positional deviation of the image formed on the recording material is suppressed.

  According to the invention described in claim 2, as compared with the case where the invention described in claim 2 is not employed, the recording material can be reliably restrained by the rotating body.

  According to the invention described in claim 3, as compared with the case where the invention described in claim 3 is not adopted, the recording material can be reliably restrained by the rotating body.

  According to the fourth aspect of the present invention, it is possible to suppress the conveyance failure of the recording material due to the transmission of the conveyance force from both the conveyance unit and the rotating body.

  According to the fifth aspect of the present invention, the fluctuation of the recording material conveyance speed that occurs when the recording material enters the rotating body that holds the unfixed image is reduced, and the positional deviation of the image formed on the recording material is reduced. A program is provided for performing suppressed control.

(Example of image forming apparatus)
FIG. 1 is a conceptual diagram showing an example of an image forming apparatus using the invention. FIG. 1 shows an image forming apparatus 100. The image forming apparatus 100 includes a paper storage device 101 that stores a paper 102 that is an example of a recording material. The paper 102 is sent out to the transport path 103 by the function of a paper feed device (not shown). As the recording material, a resin material such as OHP paper can be used.

  A transport roll mechanism 128 is disposed on the downstream side of the paper storage device 101 in the paper transport direction, and a paper feed roll 104 is disposed on the downstream side thereof. The paper feed roll 104 has a function of feeding paper to the secondary transfer unit 106. The paper feed roll 104 has a structure that can be rotated by a paper feed roll driving motor 11 fixed to the tip of the arm 12. The other end of the arm 12 is fixed to a rotating shaft of a roll contact / non-contact drive motor 13 fixed to the housing of the apparatus via a gear mechanism (not shown).

  By rotating the roll contact / non-contact drive motor 13, the arm 12 is rotated, and the paper feed roll 104 is moved to the position of 15 (position where contact with the paper is possible) or 16 (position of contact with the paper). To the position retracted from the position). In other words, the function of the roll contact / non-contact drive motor 13 is such that the paper feed roll 104 comes into contact with the paper and has a transport function (position 15), and the paper feed roll 104 does not touch the paper and the transport function works. No state (position of reference numeral 16) can be selected.

  An opposing roll 105 is disposed in contact with the paper feed roll 104. When the paper feed roll 104 is rotated while the paper feed roll 104 is at the position of reference numeral 15, the paper is transferred to the secondary transfer unit 106 with the paper sandwiched between the paper feed roll 104 and the opposing roll 105. It is sent.

  Between the paper feed roll 104 and the secondary transfer unit 106, a paper detection sensor 107 that detects the paper fed to the secondary transfer unit 106 is disposed. The paper detection sensor 107 includes a light emitting element 107a and a light receiving element 107b, and detects the presence of paper on the optical axis by blocking light emitted from the light emitting element 107a and received by the light receiving element 107b.

  The secondary transfer unit 106 includes a secondary transfer roll 108 and a counter roll 109. The secondary transfer roll 108 is driven and rotated by a motor not shown in FIG. The secondary transfer roll 108 has a metal cylindrical structure and includes a metal rotation shaft. The rotating shaft is supported in a rotatable state by a casing of an apparatus (not shown) and is given a potential from the bias voltage generating circuit 110 by a brush contact mechanism. By this mechanism, a bias voltage is applied to the secondary transfer roll 108. This bias voltage is a positive value with respect to the ground potential. In addition, a rotational force is applied to the rotating shaft by the motor described above via a gear mechanism (not shown).

  The counter roll 109 is rotatable and has a metal surface. The opposing roll 109 is in contact with a rotatable roll 111 made of metal. The shaft (not shown) of the conduction roll 111 is connected to the housing of the apparatus by a brush mechanism (not shown) and is set to the ground potential. That is, the surface potential of the facing roll 109 is set to the ground potential.

  A transfer belt 112, which is an example of a rotating body that holds an unfixed image, is sandwiched between the secondary transfer roll 108 and the facing roll 109. The transfer belt 112 is made of rubber, and is stretched between the facing roll 109, the guide roll 113, and the drive roll 114. The guide roll 111 rotates according to the rotation of the transfer belt 112. The drive roll 114 is driven and rotated by a motor not shown in FIG.

  FIG. 1 shows primary transfer devices 115, 116, 117 and 118. Each of these primary transfer devices includes a photosensitive drum, a cleaning device, a charging device, an exposure device, a developing device, and a primary transfer roll. The primary transfer devices 115, 116, 117, and 118 form toner images of Y (yellow), M (magenta), C (cyan), and K (black), and transfer the toner images to the rotating transfer belt 112. . As a result, the YMCK toner images are superimposed, and a color toner image (unfixed image) is formed on the transfer belt 305.

  The unfixed toner image on the transfer belt 112 is secondarily transferred onto the sheet fed by the function of the sheet feeding roll 104 in the secondary transfer unit 106. At this time, in the secondary transfer unit 106, the secondary transfer roll 108, the paper, the transfer belt 112, and the opposing roll 109 are overlapped in this order. Then, a pressure and a bias voltage are applied between the secondary transfer roll 108 and the opposing roll 100, whereby secondary transfer of an unfixed image from the transfer belt 112 onto the sheet is performed.

  A transport belt mechanism 119 is disposed on the downstream side of the secondary transfer unit 106. The transport belt mechanism 119 uses the suction force of a fan (not shown) to attract the sheet to the belt surface and further transport it in the downstream direction (right direction in FIG. 1). A fixing device 120 is disposed on the downstream side of the transport belt mechanism 119. The fixing device 120 includes a heating roll 121 and a pressure roll 122. When the sheet is sandwiched between the heating roll 121 and the pressure roll 122, heat and pressure are applied, and the unfixed image on the sheet is fixed to the sheet.

  A conveyance roll mechanism 123 is disposed on the downstream side of the fixing device 120. The transport roll mechanism 12 sends out the paper discharged from the fixing device 120 to the outside of the apparatus or the transport roll mechanism 124. The transport roll mechanism 124 sends the paper sent from the transport roll 123 to the reversing device 125 and sends the paper sent from the reversing device 125 to the transport path 126. A transport roll mechanism 127 is disposed in the transport path 126 to send the paper transported in the left direction in the figure to the transport roll mechanism 128. Here, the conveyance path 126 is a conveyance path used when forming an image on both sides of a sheet.

(Control system)
Hereinafter, an example of a control system in the image forming apparatus 100 illustrated in FIG. 1 will be described. FIG. 2 is a block diagram showing a part of the control system of the image forming apparatus 100 shown in FIG. FIG. 2 shows a control system related to the secondary transfer performed by the secondary transfer unit 106 of FIG.

  FIG. 2 shows the main control circuit 201. The main control circuit 201 controls the overall operation of the image forming apparatus 100. The main control circuit 201 has a function as a computer including a CPU, a RAM, a ROM, and an interface circuit. A circuit that performs image processing is arranged separately from the main control circuit 201 (not shown). FIG. 2 shows a control system related to secondary transfer, but the main control circuit 201 also performs control relating to discharge of paper from the apparatus, primary transfer processing, fixing processing, and the like. Since the description of the configuration and operation related to these controls is the same as that of a normal image forming apparatus, description thereof will be omitted.

  The operation device 202 includes a touch panel and an interface circuit for operating the image forming apparatus 100. By operating the operation device 202, various settings for image formation (for example, setting of paper and the number of copies to be output) are performed.

  The motor drive circuit 1 (203) drives a transfer belt drive motor 204 (not shown in FIG. 1) that drives a drive roll 114 that moves the transfer belt 112. The motor drive circuit 1 (203) 203 rotates the transfer belt drive motor 204 at a predetermined rotation speed based on a control signal from the main control circuit 201. This rotational speed is variable and can be determined by the control of the main control circuit 201. In the following, the rotation speed refers to the surface speed of the rotating member.

  The motor drive circuit 2 (205) drives a secondary transfer roll drive motor 206 (not shown in FIG. 1) that rotates the secondary transfer roll. The motor drive circuit 2 (205) rotates the secondary transfer roll drive motor 206 at a predetermined rotation speed based on a control signal from the main control circuit 201. This rotational speed is variable and can be determined by the control of the main control circuit 201.

  The motor drive circuit 3 (207) drives the paper feed roll drive motor 11 that rotates the paper feed roll 104. The paper feed roll drive motor 11 rotates the paper feed roll 104 at a predetermined rotational speed based on a control signal from the main control circuit 201. This rotational speed is variable and can be determined by the control of the main control circuit 201.

  The paper feed roll contact / non-contact control circuit 209 drives a paper feed roll contact / non-contact drive motor 13 for moving the position of the paper feed roll 104. According to this configuration, in response to the control signal from the main control circuit 201, the paper feed roll contact / non-contact control circuit 209 controls the rotational angle position of the paper feed roll contact / non-contact drive motor 13 to feed the paper. The position at which the roll 104 comes into contact with the paper and a driving force for conveying the paper can be applied to the paper (the position indicated by reference numeral 15 in FIG. 1), or the driving force for conveying the paper without being able to contact the paper is applied to the paper. The operation of selecting one of the positions where the position cannot be performed (the position indicated by reference numeral 16 in FIG. 1) is performed.

  The bias voltage control circuit 211 controls the bias voltage generation circuit 110 and adjusts the potential applied to the secondary transfer roll 108 by the bias voltage generation circuit 110. In this example, the potential difference between the first potential when the toner image on the transfer belt 112 is transferred to the sheet and the opposing roll 109 and the secondary transfer roll 108 is 20% larger than the first potential. The bias voltage control circuit 211 performs control capable of selecting the second potential. For example, 4 kV is selected as the first potential, and 4.8 kV is selected as the second potential.

  The paper detection sensor 107 detects the presence of the paper and outputs a detection signal when the paper blocks between the light emitting element 107a and the light receiving element 107b. This detection signal is sent to the main control circuit 201 and used for the control described later.

(Basic operation example)
Hereinafter, an example of a basic operation of the image forming apparatus 100 will be described. First, the paper stored in the paper storage device 101 is sent out to the transport path 103 by the function of a paper feed device (not shown). The sheet is conveyed rightward in the drawing by the sheet feeding roll 104 and is fed to the secondary transfer unit 106.

  The YMCK toner images are stacked on the transfer belt 112 by the operation of the primary transfer devices 115 to 118 in accordance with this timing, and a color toner image (unfixed image) is formed. The color toner image on the transfer belt 112 is secondarily transferred to the paper fed from the paper feed roll 104 in the secondary transfer unit 106. At this time, control to be described later using a bias voltage is performed in order to reduce fluctuations in the conveyance speed of the sheet that occurs when the sheet enters the transfer belt 112 and to suppress positional deviation of an image formed on the sheet. Thereafter, the sheet is sent to the fixing device 120 by the operation of the belt conveyance mechanism 119, where the image is fixed on the sheet. The sheet on which the image fixing process has been performed is discharged out of the apparatus by the action of the transport roll mechanism 123 (or is sent out toward the reversing apparatus 125).

(Details of secondary transfer process 1)
Hereinafter, an example of control performed during the secondary transfer operation in the secondary transfer unit 106 will be described. FIG. 3 is a timing chart showing an example of the operation mode. 3 shows the state of operation of the paper feed roll contact / non-contact drive motor 13, the state of operation of the paper feed roll drive motor 11, the state of operation of the secondary transfer roll drive motor 206, the secondary transfer roll. The state of the absolute value (potential difference) of the bias voltage applied between 108 and the opposing roll 109 is described with the horizontal axis as the time axis. FIG. 3 shows a state from a state where the sheet is being conveyed by the sheet feeding roll 104 to a state after a while after the secondary transfer of the image is started on the sheet.

  Hereinafter, an example of the secondary transfer process will be described. FIG. 4 is a flowchart showing an example of a procedure for performing the control shown in FIG. The control shown in FIGS. 3 and 4 is executed by the CPU in the main control circuit 201 from the operation program stored in the memory in the main control circuit 201 of FIG. The operation program may be provided via a recording medium such as a communication unit or a disk storage device.

  First, in FIG. 1, the paper feed roll 104 is at a position of reference numeral 15. In this state, the paper feed roll 104 rotates in contact with the paper, and the paper feeds the paper feed path 103 in the right direction in FIG. 1. Assuming that the Further, the transfer belt 112 rotates counterclockwise in the figure, and the secondary transfer roll driving motor 206 (see FIG. 2) rotates so that the surface of the secondary transfer roll 108 has the same speed as the transfer belt 112. Suppose you are.

  In this state, when the paper reaches the portion of the paper detection sensor 107, the paper is detected by the paper detection sensor 107 (step S401). When the paper is detected by the paper detection sensor 107, the front edge of the paper contacts the secondary transfer roll 108 based on the paper conveyance speed and the positional relationship between the paper detection sensor 107 and the secondary transfer unit 106. Time is calculated (step S402). Here, a predetermined value is used as the sheet conveyance speed.

  Next, the operation timing of each motor shown in FIG. 3 is set (step S403). That is, the timing at which the sheet feeding roll contact / non-contact driving motor 13 is operated to retract the sheet feeding roll 104 from the conveyance path, the timing at which the sheet feeding roll driving motor 11 is turned off, and the secondary transfer roll driving motor. The control content for changing the rotation speed 206 at the timing shown in FIG. 3 is set (step S403). Further, the control content for changing the absolute value of the bias voltage applied between the secondary transfer roll 108 and the opposing roll 109 at the timing shown in FIG. 3 is set (step S404).

  And the control which performs the matter set by said step S403 and step S404 at the timing shown in FIG. 3 is performed (step S405). When the execution of each setting item is finished, the process is finished (step S406).

  The time chart shown in FIG. 3 will be described. The reason why the paper feed roll contact / non-contact driving motor 13 is operated at the timing shown in FIG. 3 is as follows. First, when the sheet comes into contact with the secondary transfer roll 108, a driving force is applied to the sheet from both the sheet feeding roll 104 and the secondary transfer roll 108. In order to stably carry the paper, it is necessary to reliably carry out the paper feeding from the paper feeding roll 104 and receive the paper by the secondary transfer roll 108. For this purpose, a state in which the driving force from both the rolls is simultaneously received is necessary. On the other hand, receiving a driving force simultaneously from two rolls whose positions are shifted in the transport direction causes a slip between the roll and the sheet due to a slight difference in the driving force (rotational speed) of the two rolls. This may cause fluctuations in the transport speed. In order to balance these two matters, in this embodiment, the paper feed roll contact / non-contact driving motor 13 is operated at the timing shown in the drawing, and the paper feed roll 104 is retracted from the paper contact position 15 to Transition from the driving state of the feeding roll 104 to the paper to the driving state of the paper by the secondary transfer roll 108 is performed smoothly.

  In FIG. 3, the paper feed roll drive motor 11 is stopped after the paper feed roll 104 is retracted, so that the paper feed roll drive motor 11 does not rotate unnecessarily.

  The secondary transfer roll driving motor 206 reduces the rotational speed at the stage when the secondary transfer roll 108 comes into contact with the paper when the rotational speed is the same as the rotational speed of the transfer belt (in this example, 0. 0). 3% lower). This is because the driving force of the paper feed roll 104 is mainly reduced by reducing the driving force of the secondary transfer roll 108, thereby preventing the paper from slipping, and by slightly loosening the paper, the paper conveyance failure is prevented. This is to prevent it.

  Then, at a timing after the leading edge of the paper passes through the secondary transfer roll 108, the rotational speed of the secondary transfer roll 108 is increased from the rotational speed of the transfer belt 112 (in this example, 0.3% increase). Speed). This is because the sheet is surely captured by the secondary transfer roll 108 and the sheet is reliably restrained by the secondary transfer roll 108. Thereafter, the rotation speed of the secondary transfer roll 108 is matched with the rotation speed of the transfer belt 112, and the subsequent conveyance is performed.

  The reason for applying the bias voltage shown in FIG. 3 will be described. Before the sheet comes into contact with the secondary transfer roll 108, the absolute value of the transfer bias is set to a value that is 20% higher than the optimum value for toner image transfer (secondary transfer). The transfer bias has a negative potential with respect to the transfer belt 112 on the paper side, thereby attracting toner particles charged to a positive charge to the paper side, thereby transferring the toner image on the transfer belt 112 onto the paper. There is a function to do. Note that a value obtained through experiments is used as the optimum bias voltage value for toner image transfer.

  The toner particles transferred onto the paper are attracted to the negative potential secondary transfer roll 108 on the back surface of the paper, so that the paper is attracted (or pressed) to the secondary transfer roll 108 by this bias voltage. That is, the bias voltage for transferring the toner image also has an action of attracting the paper to the transfer roll 108. This phenomenon has been confirmed by experiments.

  FIG. 5 shows the relationship between the potential difference (absolute value of the bias voltage) between the secondary transfer roll 108 and the opposing roll 109 and the force for pulling out the paper sandwiched between the secondary transfer roll 108 and the transfer belt 112. It is a graph which shows the result of having measured. Here, in the configuration shown in FIG. 1, when the secondary transfer roll 108 and the transfer belt 112 are fixed so as not to move, and a sheet having a width of 15 mm and a length of 200 mm is sandwiched therebetween, and the potential difference of the bias voltage is changed. The force required to pull out the paper was measured with a push-pull gauge. The measurement is performed five times, and the average value of the maximum values in each measurement is plotted in FIG. In addition, the paper used what coated the surface called glossy paper for glossiness.

  As shown in FIG. 5, it is observed that the paper tends to be difficult to pull out by increasing the potential difference due to the bias voltage. This means that the force with which the sheet is attracted to the secondary transfer roll 108 increases by increasing the absolute value of the bias voltage.

  In the control shown in FIG. 3, this phenomenon is utilized, and the absolute value of the transfer bias is an optimum value for transfer for a certain period after the sheet starts to contact the secondary transfer roll 108 (in this example, the time for which the sheet advances by 20 mm). The value is increased by 20%. By doing so, the binding force of the secondary transfer roll 108 on the sheet using the transfer bias voltage is increased.

  Then, when the sheet advances by 20 mm and the sheet is reliably restrained by the secondary transfer roll 108, the transfer bias value is returned to a value suitable for transfer. Thus, the paper is surely restrained (supplemented) by the secondary transfer roll 108, and the positional deviation of the image on the paper is prevented. In addition, the occurrence of transfer failure due to the absolute value of the transfer bias being too high can be suppressed.

(Details of secondary transfer process 2)
FIG. 6 is a timing chart showing another example of the operation mode. In the example shown in FIG. 6, in addition to the example shown in FIG. 3, the transfer bias is increased when the paper feed roll 104 is retracted, and the secondary transfer roll 108 is decelerated and accelerated, and the secondary transfer from the paper feed roll 104 is performed. Variations in the sheet conveyance speed during conveyance to the roll 108 are suppressed.

  That is, as shown in FIG. 6, at the timing when the paper feed roll 104 is retracted from the state in contact with the paper, the rotational speed of the secondary transfer roll 108 is a value that is reduced by 3% from the speed matched with the transfer belt 112. Change to At the same time, the absolute value of the transfer bias is increased by 20% from the value suitable for transfer, and the binding force of the sheet to the secondary transfer roll 108 is increased. Thereby, after the driving force of the paper feeding roll 104 is lost, the secondary transfer roll 108 exerts the restraining force on the paper smoothly without slipping or the like.

  Then, at the stage where the binding force of the secondary transfer roll 108 to the sheet is sufficiently applied (in this example, when the sheet moves 15 mm), the transfer bias value is returned to an appropriate value for transfer, and the secondary transfer roll The rotational speed 108 is set to a value that matches the speed of the transfer belt 112.

  In the two examples described above, the bias generation circuit is included in a period including the time of contact with the secondary transfer roll 108 when the toner image formed on the transfer belt 112 is transferred to the sheet conveyed through the sheet conveyance path 103. The absolute value of the bias applied from 110 is set to a value larger than the value suitable for the secondary transfer. The bias voltage applied at the time of the secondary transfer exerts a force for bringing the paper into close contact with the secondary transfer roll 108. Therefore, by the above operation, the binding force of the secondary transfer roll 108 to the paper is increased, and the fluctuation in the conveyance speed of the paper is increased. This suppresses the positional deviation of the image formed on the paper. Further, by controlling the rotation speed of the secondary transfer roll when the sheet contacts the secondary transfer roll 108, fluctuations in the sheet conveyance speed are further suppressed.

  The present invention can be used in a technique for forming an image.

1 is a conceptual diagram illustrating an example of an image forming apparatus using the invention. FIG. 2 is a block diagram illustrating a part of a control system of the image forming apparatus illustrated in FIG. 1. It is a timing chart which shows an example of timing control in an embodiment. It is a flowchart which shows an example of the procedure of the process in embodiment. It is a graph which shows the data which measured the change of the adhesive force to the transfer roll at the time of changing the bias voltage applied at the time of transcription | transfer. It is a timing chart which shows another example of timing control in an embodiment.

  DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 101 ... Paper storage apparatus, 102 ... Paper, 103 ... Paper conveyance path, 104 ... Paper feed roll, 105 ... Opposite roll, 106 ... Secondary transfer part, 107 ... Paper detection sensor, 107a ... Light emitting element 107b ... light receiving element, 108 ... secondary transfer roll, 109 ... opposite roll, 110 ... bias voltage generation circuit, 111 ... conducting roll, 112 ... transfer belt, 113 ... guide roll, 114 ... drive roll, 115-118 ... Primary transfer device, 119 ... belt transport mechanism, 120 ... fixing device, 121 ... heating roll, 122 ... pressure roll, 123 ... transport roll mechanism, 124 ... transport roll mechanism, 125 ... reversing device, 126 ... transport path, 127 ... Transport roll mechanism, 128... Transport roll mechanism.

Claims (5)

A rotating body that holds an unfixed image;
Voltage control means for controlling a voltage applied between the recording material and the rotating body in a state where the recording material is in contact with the rotating body,
The voltage control means includes
Performing a control of applying a first potential difference between the recording material and the rotating body in a first period including a time when the recording material starts to contact the rotating body;
An image forming apparatus that performs control to apply a second potential difference smaller than the first potential difference between the recording material and the rotating body in a second period after the first period. .   Rotational speed control means for controlling the rotating body to be a first rotational speed during the first period and for controlling the rotating body to be a second rotational speed during the second period. The image forming apparatus according to claim 1, further comprising:   The image forming apparatus according to claim 2, wherein the first rotation speed is lower than the second rotation speed. Further comprising transport means for transporting the recording material toward the rotating body,
The conveying means stops applying the driving force to the recording material after the recording material comes into contact with the rotating body,
The image forming apparatus according to claim 1, wherein control is performed to reduce a rotation speed of the rotating body during a period including the stop time. A program that is read and executed by a computer,
Performing a control of applying a first potential difference between the recording material and the rotating body in a first period including a time when the recording material starts to contact the rotating body holding an unfixed image;
A program for executing a control for applying a second potential difference smaller than the first potential difference between the recording material and the rotating body in a second period after the first period.

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