JP2016130798A - Control device, control method of image forming apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a radiation noise emitted from a circuit operating with a fundamental wave of a clock signal or an image signal.SOLUTION: The frequency of a fundamental wave of a clock signal (video CLK) for generating a video signal C4 is changed to disperse the frequency of the clock signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device, a control method for an image forming apparatus, and a program, and is particularly suitable for use in forming an image on a paper surface.

  In an electrophotographic image forming apparatus (for example, a copying machine or a printer), the toner is blown out at a timing after normal image output is performed in order to suppress a friction coefficient between the blade and the photosensitive drum. Is done. In this case, the toner is used as a lubricant. In the following description, such a toner blowing pattern when performing the toner blowing is referred to as a blowing pattern as necessary.

By blowing out the toner with such a blowing pattern, for example, it is possible to prevent the intermediate transfer belt from being clean and the paper from being turned over.
However, during the period when the balloon pattern is output, a halftone image is normally output. For this reason, the frequency of the image signal becomes the same frequency, and radiation noise is always radiated at a high level.
In particular, when a halftone image is output using PWM (Pulse Width Modulation) or the like, the peak value of radiated electromagnetic noise (EMI) increases, for example, high-frequency radiated noise is generated.

  As a method of suppressing radiation noise of an image forming apparatus, Patent Document 1 discloses a method of thinning out pixels (a method of including white dots in a black region). At that time, frequency spreading is performed by performing thinning at random so that the black and white frequency of the video signal (image signal) generated in units of pixels does not become constant.

JP2013-168728A

By the way, the radiation noise emitted from the image signal is determined by a synergistic effect of the fundamental wave of the clock signal and the image signal generated by the fundamental wave. However, in Patent Document 1, no countermeasure against the fundamental wave is taken. Therefore, there is a possibility that radiation noise emitted from the image signal increases.
The present invention has been made in view of such problems, and an object thereof is to suppress radiation noise generated from a circuit or an image signal operating with a fundamental wave of a clock signal.

  The control device of the present invention includes an image signal used for printing, a generation unit that generates an image signal that is not used for printing, and a variation unit that varies the frequency of the fundamental wave of the clock signal for generating the image signal. The variation means varies the frequency of the fundamental wave of the clock signal for generating the image signal in a period in which the image signal not used for printing is generated by the generation means. To do.

  ADVANTAGE OF THE INVENTION According to this invention, the radiation noise which originates in the circuit and image signal which are operate | moving with the fundamental wave of a clock signal can be suppressed.

1 is a diagram illustrating a configuration of an image forming apparatus. It is a figure which shows the structure of an image formation part. It is a figure which shows a noise spectrum. It is a figure which shows the relationship between the frequency to change and time. It is a figure which shows the relationship between a TOP signal and an image output range. 3 is a flowchart illustrating a first example of an operation of the image forming apparatus. It is a timing chart of ON / OFF of SSCG. 12 is a flowchart illustrating a second example of the operation of the image forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
First, the first embodiment will be described.
In the present embodiment, a case where the image forming apparatus is a laser beam printer will be described as an example. However, the image forming apparatus is not limited to the laser beam printer as long as it is an electrophotographic image forming apparatus. The image forming apparatus may be, for example, an MFP (Multi Function Peripheral).

FIG. 1 is a diagram illustrating an example of a configuration of an image forming apparatus.
In FIG. 1, the image forming apparatus includes a control unit 101 and an image forming unit 201. The control unit 101 and the image forming unit 201 are connected via a cable 111 so that they can communicate with each other.

FIG. 2 is a diagram illustrating an example of the configuration of the image forming unit 201. Here, a case where the image forming unit 201 forms a color image based on four colors, that is, Y (yellow), M (magenta), C (cyan), and K (black) will be described as an example.
An example of the operation of the image forming unit 201 will be described with reference to FIG.

First, an outline of the operation of the image forming unit 201 will be described.
The image forming unit 201 forms an electrostatic latent image with exposure light that is turned on based on the exposure time obtained from the control unit 101 shown in FIG. Next, the image forming unit 201 develops the electrostatic latent image to form a single color toner image. Then, the image forming unit 201 forms a multicolor toner image by superimposing the single color toner images. Further, the image forming unit 201 transfers the multicolor toner image to the transfer material 11 and fixes the multicolor toner image on the transfer material 11.

Next, the configuration and operation details of the image forming unit 201 will be described.
The image forming unit 201 includes paper feeding units 21a and 21b, photosensitive drums 22Y, 22M, 22C and 22K, injection chargers 23Y, 23M, 23C and 23K, scanner units 24Y, 24M, 24C and 24K, and toner cartridges 25Y and 25M. , 25C, 25K. Further, the image forming unit 201 includes developing devices 26Y, 26M, 26C, and 26K, an intermediate transfer belt 27, a transfer roller 28, a cleaning unit 29, a fixing unit 30, a density sensor 31, and an intermediate transfer belt driving roller 32.

The transfer material 11 is fed from the paper feed unit 21a or 21b.
The photosensitive drums 22Y, 22M, 22C, and 22K rotate by receiving drive transmission from a motor (not shown). This motor rotates the photosensitive drums 22Y, 22M, 22C, and 22K in the counterclockwise direction according to the image forming operation.

Around the photosensitive drums 22Y, 22M, 22C, and 22K, there are injection chargers 23Y, 23M, 23C, and 23K for charging the photosensitive drums 22Y, 22M, 22C, and 22K, and developing devices 26Y, 26M, and 26C that perform development. , 26K.
The developing units 26Y, 26M, 26C, and 26K are provided with developing sleeves 26YS, 26MS, 26CS, and 26KS, respectively, and rotate with toner development.
The intermediate transfer belt 27 rotates in the clockwise direction by the rotation of the intermediate transfer belt drive roller 32. The intermediate transfer belt drive roller 32 rotates upon receiving drive transmission from a motor (not shown).

In forming an image, the rotating photosensitive drums 22Y, 22M, 22C, and 22K are charged by the injection chargers 23Y, 23M, 23C, and 23K, and then the surfaces of the photosensitive drums 22Y, 22M, 22C, and 22K are exposed.
The scanner units 24Y, 24M, 24C, and 24K selectively expose the photosensitive drums 22Y, 22M, 22C, and 22K to form electrostatic latent images. The electrostatic latent image is visualized by developing the toner with the developing devices 26Y, 26M, 26C, and 26K.

The single-color toner image is superimposed and transferred onto the intermediate transfer belt 27 that rotates clockwise as the photosensitive drums 22Y, 22M, 22C, and 22K rotate.
Thereafter, the transfer roller 28 comes into contact with the intermediate transfer belt 27 to nipping and conveying the transfer material 11, and the multicolor toner image on the intermediate transfer belt 27 is transferred to the transfer material 11 (the paper surface thereof). The density of the toner patch formed on the surface of the intermediate transfer belt 27 is measured by the density sensor 31.
Heat and pressure are applied to the transfer material 11 holding the multicolor toner image at the fixing unit 30. As a result, the multicolor toner image is fixed on the surface of the transfer material 11.

  The transfer material 11 after the multicolor toner image is fixed is then discharged to a discharge tray (not shown) by a discharge roller (not shown). The toner remaining on the intermediate transfer belt 27 is cleaned by the cleaning unit 29, and the cleaned toner is stored in a cleaner container.

Next, an example of the configuration of the control unit 101 shown in FIG. 1 will be described.
The CPU 104 executes a control program stored in the ROM unit 106 and controls the entire image forming apparatus.
The RAM unit 105 provides recording data transmitted from the host computer, which stores recording data for printing, a work area necessary as a work memory when the CPU 104 executes various controls, and the like. To do.
The control circuit 103 connects the CPU 104 with the ROM unit 106 and the RAM unit 105. Further, the control circuit 103 performs transfer control of image data to the image forming unit 201. The control circuit 103 is, for example, an ASIC (Application Specific Integrated Circuit).

  The USB I / F 107 is a USB interface unit. The NWI / F 108 is a network interface unit. The USB I / F 107 and the NWI / F 108 are for communicating with an external device. For example, the USB I / F 107 and the NWI / F 108 exchange control signals with the host computer and receive data transmitted from the host computer.

The image control unit 102 converts the image data of each color into a video signal (image signal) and transfers it to the image forming unit 201.
The oscillator 110 generates a fundamental wave of video CLK (clock signal) to be transferred to the image forming unit 201.
The SSCG (Spread Spectrum Clock Generator) 109 has the following functions. That is, the SSCG 109 varies the frequency of the video CLK with a constant period around the fundamental frequency of the video CLK input from the oscillator 110 based on the control signal C1 output from the control circuit 103. By the control signal C1 input to the SSCG 109, the SSCG 109 sets ON / OFF of the SSCG (whether or not to change the frequency), a cycle for changing the frequency, and a spreading factor of the frequency. can do.

Here, the fluctuation of the frequency by the SSCG 109 will be described.
FIG. 3 is a diagram simply illustrating an example of a noise spectrum radiated from the image forming apparatus.
FIG. 3 shows the relationship between the electric field strength of the fundamental wave of the clock signal used and the frequency (clock frequency) of the fundamental wave of the clock signal.
In FIG. 3, SSCG = OFF indicates that the frequency is not changed, and SSCG = ON indicates that the frequency is changed.

As shown in FIG. 3, the peak value of the electric field strength when SSCG = ON is reduced with respect to the peak value of the electric field strength when SSCG = OFF. Further, the spectrum width when SSCG = ON is wider than the sharp spectrum width when SSCG = OFF.
Actually, by giving a slight fluctuation to the clock frequency, it is possible to dissipate the energy concentrated in a linear shape in the frequency domain of the fundamental wave of the clock signal used. Thereby, the peak value of electric field strength can be reduced.

FIG. 4 is a diagram illustrating an example of the relationship between the frequency to be varied and time. In FIG. 4, the frequency is shown as a relative value based on the frequency of the clock signal when SSCG = OFF.
As shown in FIG. 4, for example, the frequency can be spread by changing the frequency up and down at a constant cycle around the frequency of the clock signal when SSCG = OFF.

  Returning to the description of FIG. 1, the image forming unit I / F signal C <b> 2 (control signal or the like) is transmitted and received between the CPU 104 and the image forming unit 201, whereby the control unit 101 and the image forming unit 201. Various types of information are exchanged. As described above, the control unit 101 and the image forming unit 201 are connected to each other via the cable 111 so that they can communicate with each other. Various signal lines are connected to the control unit 101 and the image forming unit 201 by the cable 111.

The image forming unit 201 that has received a print start command in response to the image forming unit I / F signal C2 starts conveying the transfer material 11 from the paper supply unit 21a or 21b.
When it is detected by a sensor (not shown) that the leading edge of the transfer material 11 has passed a specific position, the image forming unit 201 indicates this as a sub-scanning synchronization signal (referred to as TOP signal C3 in the following description). To the image control unit 102.

Upon receiving the TOP signal C 3, the image control unit 102 requests image data from the control circuit 103 and receives the image data stored in the RAM unit 105 via the control circuit 103.
In the image control unit 102, the number of pixels in the main scanning direction and the number of lines in the sub scanning direction are set in advance before printing.
The image control unit 102 is configured so that the number of pixels in the main scanning direction and the number of lines in the sub scanning direction set in the image control unit 102 are synchronized with a main scanning synchronization signal (not shown) and a TOP signal C3, respectively. The video signal C4 is output to the image forming unit 201.
Therefore, the TOP signal C3 has a meaning of a timing signal indicating an image writing start position.

  FIG. 5 is a diagram illustrating an example of the relationship between the TOP signal C3 and the image output range. The image output range is a period during which an image is formed on the transfer material 11 and a period during which toner is blown out according to a blowing pattern. As described above, the blowing pattern is a toner blowing pattern when the toner is blown out at a timing after normal image output is performed for the purpose of suppressing the friction coefficient between the blade and the photosensitive drum. In this case, the toner is used as a lubricant for components (for example, an intermediate transfer belt and a photosensitive drum) for forming an image on a paper surface.

In FIG. 5, first, the TOP signal C31 for the image 1 is output. When the output of the image data of the image 1 is completed, a balloon pattern TOP signal C32 is output.
In this embodiment, images are formed in the order of Y (yellow), M (magenta), C (cyan), and K (black). The image control unit 102 that has received the TOP signal C31 outputs image data after an area in the transfer material 11 corresponding to a preset number of leading margin lines is sent out.

When the image data of image 1 is output, a balloon pattern TOP signal C32 is output.
In the case of continuous printing, when the output of the image data of image 1 and the balloon pattern is completed, the TOP signal C33 for image 2 is output. When receiving the TOP signal C33 for the image 2, the image control unit 102 starts outputting the image data of the image 2 similarly to the image data of the image 1.

  An example of the operation of the image forming apparatus (control unit 101) will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 6 is controlled by, for example, the CPU 104 and various programs (firmware) stored in the ROM unit 106.

When printing is started, in step S601, the host computer or the image forming apparatus creates an image to be printed.
In step S <b> 602, the image control unit 102 transmits a print start command to the image forming unit 201, and then waits for input of a TOP signal C <b> 3 transmitted from the image forming unit 201.

When the TOP signal C3 is input, the process proceeds to step S603. In step S603, the control circuit 103 determines whether the video signal to be output is a balloon pattern signal.
As a result of the determination, if the video signal to be output is a balloon pattern signal, the process proceeds to step S605. On the other hand, if the video signal to be output is not a balloon pattern signal but an image data signal for forming an image on the transfer material 11, the process proceeds to step S604.

  In step S604, the control circuit 103 outputs a control signal C1 indicating SSCG = OFF to the SSCG 109. The SSCG 109 outputs the fundamental wave of the video CLK input from the oscillator 110 to the image control unit 102 as it is based on the control signal C1. In this case, the frequency of the fundamental wave of the video CLK is not changed. If the process proceeds to step S605 in the previous determination in step S603 and the process proceeds to step S604 in the current determination in step S603, the frequency of the fundamental wave of the video CLK is the original state before the change. Will return.

  On the other hand, in step S605, the control circuit 103 outputs a control signal C1 indicating SSCG = ON to the SSCG 109. The SSCG 109 varies the frequency of the fundamental wave of the video CLK input from the oscillator 110 based on the control signal C1, and outputs the fundamental wave of the video CLK having the varied frequency to the image control unit 102.

FIG. 7 is a timing chart showing an example of the timing at which SSCG is turned ON / OFF in a section in which a video signal is output.
In FIG. 7, at the timing when the TOP signal C31 for image 1 is input, the control circuit 103 outputs a control signal C1 indicating SSCG = OFF to the SSCG 109.
The SSCG 109 that has received the control signal C1 indicating SSCG = OFF continues to output the fundamental wave of the video CLK input from the oscillator 110 to the image control unit 102 without spreading.

  As shown in the SSCGOFF section of the SSCG effective section in FIG. 7, the video CLK until the TOP signal C32 for the balloon 1 is input to the control circuit 103 after the TOP signal C31 for the image 1 is input to the control circuit 103. The frequency of the fundamental wave is not changed. That is, during the period from when the TOP signal C31 for image 1 is input to the control circuit 103 to when the TOP signal C32 for the next balloon pattern is input to the control circuit 103, the frequency variation as the fundamental wave of the video CLK No clock signal (CLK) is used.

On the other hand, at the timing when the balloon pattern TOP signal C 32 is input to the control circuit 103, the control circuit 103 outputs a control signal C 1 indicating SSCG = ON to the SSCG 109.
The SSCG 109 to which the control signal C1 indicating SSCG = ON is input continuously spreads the fundamental wave of the video CLK input from the oscillator 110 to the image control unit 102 after being spread at a constant period.

  As shown in the SSCGON section of the SSCG effective section in FIG. 7, the video CLK until the TOP signal C33 for the image 2 is input to the control circuit 103 after the balloon pattern TOP signal C32 is input to the control circuit 103. The frequency of the fundamental wave of fluctuates at a constant period. As a result, the frequency of the video CLK is spread.

Returning to the description of FIG. 6, in step S606, the image control unit 102 sends the video signal C4 to the image after the area corresponding to the preset number of leading margin lines is sent out. Output to the forming unit 201.
Next, in step S607, the control circuit 103 waits until the output of the video signal C4 for one page or one pattern is completed. When the output of the video signal C4 ends, the process proceeds to step S608.

  In step S608, the control circuit 103 determines whether all printing has been completed. As a result of this determination, if all the printing has not been completed, the process returns to step S602 and waits until the next TOP signal C3 is input. Then, the processes in steps S602 to S608 are repeatedly executed until all printing is completed. When all the printing is finished, the processing according to the flowchart of FIG. 6 is finished.

  As described above, in the present embodiment, the frequency of the clock signal is spread by changing the frequency of the fundamental wave of the clock signal (video CLK) for generating the video signal C4. Therefore, it is possible to suppress unnecessary radiation noise from a circuit or video signal operating with the fundamental wave of the clock signal.

  Further, for example, if the frequency is changed from the base of the basic clock to take measures against the fundamental wave of the video CLK, there is a risk that the image will be expanded or contracted in the main scanning direction. There is a risk of adversely affecting the quality. In particular, when forming a color image, even a slight change in frequency appears remarkably in color misregistration and the like, and there is a possibility that an accurate image cannot be reproduced.

Therefore, in the present embodiment, the SSCG is switched ON / OFF at the timing when the TOP signal C3 is input to the control circuit 103.
Specifically, the frequency of the fundamental wave of the video CLK is not changed during the period in which an image is formed on the transfer material 11 as the video signal C4. On the other hand, the frequency of the fundamental wave of the video CLK is varied during a period in which a balloon pattern signal is generated as the video signal C4. Therefore, it is possible to suppress unnecessary radiation noise from a circuit operating on the fundamental wave and a video signal without deteriorating the quality of the output image.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment, an example in which a video signal that does not form an image on the transfer material 11 (that is, that is not used for printing) is a balloon pattern signal during a period in which images are formed on a plurality of transfer materials 11. And explained. In the following description, a period during which images are formed on a plurality of transfer materials 11 is referred to as a sheet interval as necessary.
However, video signals that are not used for printing include a pattern image signal for adjusting the magnification in the main scanning direction and a pattern image signal for adjusting the resist.

Such a pattern image may be used alone to adjust the magnification and registration of the printer, but may be used between papers in the same manner as the balloon pattern.
Further, the above-described pattern image other than the balloon pattern is used for measuring an accurate distance and position. Therefore, it is not preferable to change the frequency of the fundamental wave of the video CLK.

  Therefore, even if the pattern images are used between the same paper, whether the frequency of the fundamental wave of the video CLK is changed by distinguishing the balloon pattern from the pattern image for adjusting the magnification and registration in the main scanning direction. It is necessary to determine whether or not. As described above, the present embodiment distinguishes the balloon pattern signal from the pattern image signal for adjusting the magnification in the main scanning direction and the registration between papers, and the video CLK signal is only applied to the balloon pattern signal. The difference from the first embodiment is that the frequency of the fundamental wave is varied. Therefore, in the description of the present embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals as those in FIGS.

  An example of the operation of the image forming apparatus (control unit 101) will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 8 is controlled by the CPU 104 and various programs (firmware) stored in the ROM unit 106, for example. Further, the flowchart shown in FIG. 8 shows an example of processing when a balloon pattern and a pattern image for adjusting magnification and registration in the main scanning direction are mixed between sheets.

When printing is started, in step S801, the host computer or the image forming apparatus creates an image to be printed.
In step S <b> 802, the image control unit 102 transmits a print start command to the image forming unit 201, and then waits until a TOP signal C <b> 3 transmitted from the image forming unit 201 is input.

  When the TOP signal C3 is input, the process proceeds to step S803. In step S803, the control circuit 103 determines whether the video signal to be output is an inter-paper pattern signal. In this embodiment, the inter-paper pattern signal is a balloon pattern signal, a pattern image signal for adjusting the magnification in the main scanning direction, or a pattern image signal for adjusting the resist.

  As a result of this determination, if the video signal to be output is not an inter-paper pattern but an image data signal for forming an image on the transfer material 11, the process proceeds to step S804. In step S804, the control circuit 103 outputs a control signal C1 indicating SSCG = OFF to the SSCG 109. The SSCG 109 outputs the fundamental wave of the video CLK input from the oscillator 110 to the image control unit 102 as it is based on the control signal C1. And it progresses to step S808 mentioned later.

On the other hand, if the video signal to be output is an inter-paper pattern, the process proceeds to step S805. In step S805, the control circuit 103 determines whether the video signal to be output is a balloon pattern signal.
As a result of this determination, if the video signal to be output is not a balloon pattern signal, but a pattern image signal for adjusting the magnification in the main scanning direction, or a pattern image signal for adjusting the resist, The process proceeds to step S806.

  In step S806, the control circuit 103 outputs a control signal C1 indicating SSCG = OFF to the SSCG 109. The SSCG 109 outputs the fundamental wave of the video CLK input from the oscillator 110 to the image control unit 102 as it is based on the control signal C1. And it progresses to step S808 mentioned later.

  On the other hand, if the video signal to be output is a balloon pattern signal, the process proceeds to step S807. In step S807, the control circuit 103 outputs a control signal C1 indicating SSCG = ON to the SSCG 109. The SSCG 109 varies the frequency of the fundamental wave of the video CLK input from the oscillator 110 based on the control signal C1, and outputs the fundamental wave of the video CLK whose frequency is varied to the image control unit 102. Then, the process proceeds to step S808.

When the process proceeds to step S808 as described above, the image control unit 102 outputs the video signal C4 to the image after the area corresponding to the preset number of leading margin lines is sent out. Output to the forming unit 201.
Next, in step S809, the control circuit 103 waits until the output of the video signal C4 for one page or one pattern is completed. When the output of the video signal C4 ends, the process proceeds to step S810.

  In step S810, the control circuit 103 determines whether all printing has been completed. If all the printing is not completed as a result of this determination, the process returns to step S802 and waits until the next TOP signal C3 is input. Then, the processes in steps S802 to S810 are repeatedly executed until all printing is completed. When all the printing is finished, the processing according to the flowchart of FIG. 8 is finished.

  As described above, in this embodiment, it is determined whether the video signal C4 to be output is a balloon pattern signal or another pattern image signal between sheets. If the result of this determination is that the video signal C4 to be output is a balloon pattern signal, the fundamental frequency of the video CLK is varied; otherwise, the fundamental frequency of the video CLK is not varied. Therefore, in this embodiment, in addition to the effects described in the first embodiment, it is necessary even if the pattern between the paper pattern and the pattern image for adjusting the magnification in the main scanning direction and the resist are mixed in the inter-paper pattern. There is an effect that SSCG can be applied only to a video signal.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

  101: Control unit, 109: SSCG, 110: Transmission unit, 201: Image forming unit

Claims (10)

Generation means for generating an image signal used for printing and an image signal not used for printing;
Fluctuating means for fluctuating the frequency of the fundamental wave of the clock signal for generating the image signal,
The control unit is characterized in that the frequency of the fundamental wave of the clock signal for generating the image signal is changed during a period in which the image signal not used for the printing is generated by the generation unit.   The fluctuating means fluctuates the frequency of the fundamental wave of the clock signal for generating the image signal during the period in which the image signal not used for the printing is generated by the generating means, and the image used for the printing 2. The control device according to claim 1, wherein a frequency of a fundamental wave of a clock signal for generating the image signal is not changed during a period in which the signal is generated by the generation unit.   The changing means indicates an image writing start position by changing a frequency of a fundamental wave of a clock signal for generating the image signal and setting the changed frequency to a frequency before changing. The control apparatus according to claim 2, wherein the control apparatus performs the sub-scanning synchronization signal at the input timing.   The generating means generates an image signal not used for printing in a period between a period for generating an image signal used for printing and a period for generating an image signal used for printing next to the image signal. The control device according to claim 1, wherein the control device generates and outputs the control device.   5. The image signal that is not used for printing is a signal that indicates a blowing pattern of toner used as a lubricant for a component for forming an image on a paper surface. The control device described.   If the image signal that is not used for printing is not an image signal that is generated to adjust the position at which the image is formed, the fluctuating means is the frequency of the fundamental wave of the clock signal for generating the image signal. When the image signal that is not used for printing is an image signal generated to adjust the position where the image is formed, the frequency of the fundamental wave of the clock signal for generating the image signal The control device according to claim 1, wherein the control device is not varied.   When the image signal that is not used for printing is a signal that indicates a toner blowing pattern used as a lubricant for a component that forms an image on a paper surface, the fluctuating unit generates a clock for generating the image signal. The frequency of the fundamental wave of the signal is changed, and if the image signal not used for printing is not a signal indicating a toner blowing pattern used as a lubricant for a part that forms an image on the paper surface, the image signal is generated. 5. The control device according to claim 1, wherein the frequency of the fundamental wave of the clock signal to be changed is not changed. Generation means for generating an image signal used for printing and an image signal not used for printing;
Fluctuating means for fluctuating the frequency of the fundamental wave of the clock signal for generating the image signal,
The fluctuating means does not fluctuate the frequency of the fundamental wave of the clock signal for generating the image signal used for the printing, and changes the frequency of the fundamental wave of the clock signal for generating the image signal not used for the printing. A control device characterized by being varied. A generation process for generating an image signal formed on a paper surface and an image signal not used for printing;
A variation step of varying the frequency of the fundamental wave of the clock signal for generating the image signal,
In the image forming apparatus, the fluctuating step fluctuates a frequency of a fundamental wave of a clock signal for generating the image signal in a period in which an image signal not used for the printing is generated by the generating step. Control method.   A program that causes a computer to function as each unit of the control device according to claim 1.

Images