JP2010128261A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus for executing motor control allowing quick start-up while restraining a peak current. <P>SOLUTION: A CPU determines whether an electric power source is turned on in the image forming apparatus or not (step S1). Then, the CPU starts communication between motors when the electric power source is determined to be turned on (step S2). Then, the CPU confirms the number of the motors (step S3). The CPU sets a phase shifting amount in response to the number of the motors (step S4). In concrete terms, the phase shifting amount is set to 1/N period in response to the number (N) of the motors. The CPU outputs thereafter an indication for setting the phase shifting amount (step S5). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to drive control of a motor provided in the image forming apparatus.

  In an image forming apparatus such as a multifunction machine or a copying machine, a brushless motor is generally used as a main drive source. Since the brushless motor is excellent in rotational stability by servo control, it is used as a motor suitable for a developing process that requires high rotational accuracy. Also, a brushless motor is used as the sub drive source, and is used in a transport process for transporting paper, for example.

  When executing image formation, the motor is first started, and after the motor has reached stable rotation, the image forming operation is started. When the brushless motor is started, the upper limit of the set maximum value is set at the frequency according to the PWM clock. Therefore, when a plurality of brushless motors are started simultaneously, the peak current increases because the current waveforms overlap, and the burden on the power supply device increases.

  This may also cause various problems such as power switch welding, fuse blown, electrical stress on rectifiers and other components, and adverse effects on other peripheral devices due to temporary drop in power supply voltage. There is.

  Therefore, it is necessary to increase the power supply capacity and set the standard of the circuit element to a standard product compatible with a large current, which may increase the size of the power supply device and increase the circuit cost.

  FIG. 14 is a current waveform diagram of a chopping current when start control of a plurality of motors is executed simultaneously.

  Referring to FIG. 14, here, there are shown current waveforms of chopping currents when the start control of the main motor and the sub motor is executed.

  FIG. 15 is a current waveform diagram of the total of the chopping currents of the main-side and sub-side motors.

  As shown in FIG. 15, the total peak current value of the chopping currents of the main-side and sub-side motors is approximately twice the peak current value of one of the chopping currents.

Therefore, conventionally, when driving a plurality of brushless motors, a method of shifting the start timing has been adopted in order to keep the peak current value low (Patent Document 1 and Patent Document 2). As a result, the power supply device can be downsized and the circuit cost can be reduced without increasing the power supply capacity.
JP 2004-343892 A JP 2007-124829 A

  However, in the methods described in Patent Documents 1 and 2, when a plurality of motors are provided, the motor start timing is shifted, that is, as shown in FIG. A method of shifting the start timing with the motor was adopted. In the case of this method, as shown in FIG. 16 (b), since the start-up sequence on the sub-side is started up after the start-up sequence on the main side is completed, the start-up time of all motors becomes long. There is a problem that the first copy time, which is the time until the first printing is started, becomes long.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that executes motor control capable of starting at high speed while suppressing a peak current.

  An image forming apparatus according to the present invention includes a developing unit that forms an electrostatic latent image for transfer onto a sheet, a conveying unit that conveys the sheet, and a plurality of motors that drive at least one of the developing unit and the conveying unit. And a plurality of motor units, each including a control signal generation unit that generates a motor drive control signal for operating the corresponding motor in accordance with an input of a clock frequency of a predetermined period. A clock oscillator that oscillates a clock frequency of a predetermined period, and a clock that receives a clock frequency of a predetermined period oscillated from the clock oscillator and outputs a clock frequency of a predetermined period having a different phase to each control signal generator A phase control unit.

  Preferably, the control signal generation unit generates a motor drive control signal having a predetermined cycle including an on period in which current is supplied to a corresponding motor and an off period in which the supply of current is stopped in accordance with an input of a clock frequency having a predetermined cycle. . The control signal generation unit sets the duty ratio of the ON period in a predetermined cycle to be equal to or less than a predetermined value.

In particular, when the number of the plurality of motors is N, the predetermined value is set to 1 / N.
Preferably, the clock oscillator is a single oscillator.

  Preferably, when the number of the plurality of motors is N, the clock phase control unit outputs a predetermined clock frequency whose phases are shifted by 1 / N period to each signal generation unit.

  The image forming apparatus according to the present invention includes a clock phase control unit that receives a clock frequency of a predetermined cycle oscillated from a clock oscillator and outputs a clock frequency of a predetermined cycle having a different phase to each control signal generation unit. .

  With this configuration, the phase of the current waveform according to the motor drive control signal generated by the control signal generation unit is different for each motor, so that the peak current value can be reduced and all motors are started until the start sequence is completed. Time can be shortened.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same.

(Embodiment 1)
In the present embodiment, a case where the image forming apparatus according to the present invention is applied to a tandem digital color copying machine (hereinafter referred to as a copying machine) will be described.

  However, the image forming apparatus according to the present invention is not limited to a copying machine, and may be a printer, a facsimile machine, or a combination thereof as long as the image forming apparatus uses a DC brushless motor (hereinafter simply referred to as a motor) as a drive source. It may be an MFP (Multi Function Peripheral). Further, the printing method is not limited to the tandem method, and is not limited to the digital method. Further, it may be a monochrome machine instead of a color machine.

  The color tandem type image forming apparatus includes four color developing units each including a developing unit arranged along an intermediate transfer belt as an intermediate transfer member, and the toner images of the respective colors formed on the respective color toner images are described above. The image is transferred to an intermediate transfer belt (primary transfer), and a multicolor image is formed by superimposing each color toner. Further, the image superimposed on the intermediate transfer belt is transferred onto a sheet as a printing medium (secondary transfer), and output through a fixing process.

  FIG. 1 is a schematic cross-sectional view showing an outline of a hardware configuration of a copying machine 1 according to an embodiment of the present invention to which an image forming apparatus according to the present invention is applied.

  The copying machine 1 is a tandem digital color copying machine, and sequentially superimposes four color toners of yellow (Y), magenta (M), cyan (C), and black (K) to form a color image. Form.

  Referring to FIG. 1, copier 1 according to the embodiment of the present invention includes an image reading unit 10, a paper transport unit 20, an image forming unit 30, and a paper storage unit 40.

  The image reading unit 10 includes a loading table 3 for setting a document, a document table glass 11, and an automatic document conveyance unit 2 that automatically conveys documents set on the loading table 3 to the document table glass 11 one by one. And a discharge table 4 for discharging the read document. Further, the document reading unit 10 includes a scanner (not shown). The scanner moves parallel to the platen glass 11 by a scan motor. The scanner has an exposure lamp that illuminates the document, a reflection mirror that changes the direction of the reflected light from the document, a mirror that changes the optical path from the reflection mirror, a lens that collects the reflected light, and an electrical signal depending on the received reflected light A photoelectric conversion element such as a three-row (R, G, B) CCD (Charge Coupled Device) is included.

  The original conveyed by the automatic original conveying unit 2 is set on the original platen glass 11 and exposed and scanned when the scanner moves in parallel with the original platen glass 11. The reflected light from the document is converted into an electrical signal by the photoelectric conversion element and input to the image forming unit 30.

  The image forming unit 30 is suspended by a plurality of rollers 32, 33, and 34 so as not to be loosened, and these rollers rotate counterclockwise (in the direction of arrow A in FIG. 1) in FIG. And an intermediate transfer belt 31 that is an endless belt rotating in the same direction, and yellow (Y), magenta (M), cyan (C), and black (K) colors arranged along the intermediate transfer belt 31 at predetermined intervals. The developing units 21Y, 21M, 21C, and 21K corresponding to the toner (representing these as the developing units 21), the developing unit included in each developing unit 21, the photosensitive member, and the intermediate transfer belt 31 are paired. Transfer rollers 25Y, 25M, 25C, and 25K (representatively referred to as transfer rollers 25), and a fixing device 36 that fixes the toner image transferred to the intermediate transfer belt 31 after being transferred to the paper. It includes a controller 100, including CPU (Central Processing Unit), a motor 200, 300 for driving the respective drive mechanisms according to the instructions of the CPU.

  The paper storage unit 40 includes a paper feed cassette 41 that stores the paper S, which is a printing medium, and the paper transport unit 20 includes rollers 42, 43, 35, 37 for transporting the paper S from the paper feed cassette 41, and A paper discharge tray 38 for discharging printed paper is included.

  The controller 100 reads out and executes a program from the memory based on an instruction signal input from an operation panel (not shown) or the like, and controls the above-described units. Further, the controller 100 may be provided with a timer such as a timer, and execute the program when a predetermined time is measured. The controller 100 may be provided in the image reading unit 10, the paper transport unit 20, and the like other than the image forming unit 30.

  The controller 100 executes a program stored in the memory, thereby performing predetermined image processing on the image signal input from the image reading unit 10 or an external device, and each color of yellow, magenta, cyan, and black Create a digital signal after color conversion. The image color data for cyan, the image color data for magenta, the image color data for yellow, and the image color data for black created by the controller 100 for each color are the controller 100 is output to the exposure unit of the developing unit 21.

  The exposure device outputs a laser beam to the photoconductor based on the image data input from the controller 100, so that the surface of the uniformly charged photoconductor is exposed according to the image data, and the electrostatic latent image is generated. It is formed. A developing bias voltage is applied to the developing roller, and a potential difference is generated between the developing roller and the latent image potential of the photoreceptor. In this state, charged toner is supplied to form a toner image on the surface of the photoreceptor. The toner image formed on the surface of the photosensitive member is transferred to the intermediate transfer belt 31 as an image carrier by a constant voltage or constant current transfer roller 25. This is called primary transfer.

  The toner image primarily transferred to the intermediate transfer belt 31 is transferred onto the paper S conveyed from the paper feed cassette 41 by the roller 34. This is called secondary transfer. The toner image secondarily transferred to the paper is fixed on the paper by the fixing device 36 and is discharged to the paper discharge tray 38 as an electrophotographic image.

  Of the above-described configuration of the copying machine 1, as a driving mechanism, for example, as a developing system driving mechanism, in this example, as a mechanism, a mechanism for driving the photosensitive member in the developing unit 21, various rollers 32, 33, 34, and the like. The motor unit 200 is used. Further, it is assumed that the motor unit 300 is used as a transport system drive mechanism for a mechanism for driving the fixing device 36, a mechanism for driving the rollers 42, 43, 35, and 37 of the paper transport unit 20, and the like.

  In the present invention, the case where the development system drive mechanism and the transport system drive mechanism are each driven by two DC brushless motors will be described as an example. However, which drive mechanism drives the brushless motor is limited. Any of them may be used. Any other mechanism may be used as long as it is configured to drive using a plurality of brushless motors.

  In the copying machine 1 according to the present embodiment, the driving of the DC brushless motor is controlled by the CPU 200 in the controller 100.

  FIG. 2 is a diagram illustrating a configuration in which the motor units 200 and 300 are controlled by the CPU 105 in the controller 100.

  Referring to FIG. 2, controller 100 includes a CPU 105, a ROM (Read Only Memory) 110, and a RAM (Random Access Memory) 115.

  The RAM 115 is storage means used as a work area or buffer area for the CPU 105. The ROM 110 is a storage unit for storing a program executed by the CPU 105, and various functions are realized by the CPU 105 executing the program stored in the ROM. It is also assumed that data such as the number of revolutions of the motor for executing the motor control according to the embodiment of the present invention is also stored.

  The motor unit 200 includes a motor M1, an FG sensor F1 that generates an FG pulse that is a rotation signal based on a magnetic flux change according to the rotation speed of the rotor of the motor M1, and a motor M1 based on a PWM (Pulse Width Modulation) signal. An inverter IV1 that generates and outputs a voltage for driving the inverter, a PWM signal generator 210 that generates a PWM signal for the inverter IV1, a PWM clock oscillator 250 that oscillates a PWM clock that is a basis for generating the PWM signal, In response to the input of the PWM clock oscillated from the PWM clock oscillator 250, the PWM signal generators 210 and 310 output PWM clocks having different phases to each other, and are output from the FG sensor F1. FG pulse input and rotation direction signal DS1 given from the CPU 105 Based on the rotation instruction signal RS1 and the input of the rotation speed instruction clock RCS1 for instructing the rotation speed of the motor, an effective current value to be energized so as to achieve the target rotation speed of the motor is derived using PI calculation or the like. And a motor drive control unit 205 that controls generation of a PWM signal by the signal generation unit 210.

  The motor unit 300 includes a motor M2, an FG sensor F2 that generates an FG pulse that is a rotation signal based on a magnetic flux change according to the rotation speed of the rotor of the motor M2, and a motor M2 based on a PWM (Pulse Width Modulation) signal. An inverter IV2 that generates and outputs a voltage for driving the signal, a PWM signal generator 310 that generates a PWM signal for the inverter IV2, an input of an FG pulse output from the FG sensor F2, and a rotation direction signal provided from the CPU 105 Based on the DS2 and the rotation instruction signal RS2 and the input of the rotation speed instruction clock RCS2 for instructing the rotation speed of the motor, an effective current value to be energized so that the motor reaches the target rotation speed is derived using PI calculation or the like, A motor drive control unit 305 that controls generation of the PWM signal by the PWM signal generation unit 310. That is, the motor unit 300 is only provided with no PWM clock oscillating unit 250 and clock phase control unit 260, and has the same configuration as the motor unit 200 in other respects. The motor drive control units 205 and 305 output the state signals SS1 and SS2 to the CPU 105 when the motors M1 and M2 reach the target rotation speed. In this example, the case where the PWM clock oscillation unit 250 and the clock phase control unit 260 are provided in the motor unit 200 will be described. However, the present invention is not limited to the motor unit 200, and may be external. It may be provided in the motor unit 300.

  Here, the PWM clock output from the PWM clock oscillator 250 will be described.

FIG. 3 is a diagram illustrating a PWM clock according to the embodiment of the present invention.
Referring to FIG. 3A, the PWM clock oscillator 250 generates a triangular clock signal.

  Here, the clock phase controller 260 outputs PWM clocks having different phases to the PWM signal generators 210 and 310, respectively.

  FIG. 3B shows a PWM clock in which the phase of the PWM clock oscillated from the PWM signal generator 310 is shifted by a half period in the clock phase controller 260. In this example, as an example, the clock phase control unit 260 outputs the PWM clock oscillated and output from the PWM clock oscillation unit 250 to the PWM signal generation unit 210 and the PWM clock oscillated from the PWM clock oscillation unit 250 by half. It is assumed that the PWM clock shifted in period is output to the PWM signal generator 310.

  Therefore, the phases of the PWM clocks output to PWM signal generators 210 and 310 of motor units 200 and 300 are different from each other.

  FIG. 4 is a diagram illustrating a PWM chopping current waveform according to the first embodiment of the present invention.

  Referring to FIG. 4, the lower side is the chopping current waveform of the main side motor, and the upper side is the chopping current waveform of the sub-side motor.

  As shown in FIG. 4, the chopping current waveform is the same as that described in FIG. 14, but the phase between the chopping current waveform of the lower main motor and the chopping current waveform of the upper sub motor is There is a half cycle shift. That is, since the chopping current waveform of the main motor and the chopping current waveform of the sub motor are current waveforms that are shifted from each other by a half cycle, the peak values of the chopping current pulses are different from each other.

  FIG. 5 is a current waveform diagram of the total chopping currents of the main-side and sub-side motors according to the first embodiment of the present invention.

  Referring to FIG. 5, the total peak current value of the chopping current waveforms of the main side motor and the sub side motor is set to a peak current value lower than twice the peak current value of one side. In this example, 10 A Set to:

  Therefore, the method according to the first embodiment of the present invention makes it possible to reduce the peak current value, and simultaneously execute the start-up sequence of the main side motor and the sub side motor as shown in FIG. Therefore, it is possible to reduce the total motor startup time until the startup sequence of the main motor and the sub motor is completed.

  FIG. 7 is a flowchart illustrating a setting instruction from the CPU to the motor unit according to the first embodiment of the present invention.

  Referring to FIG. 7, first, CPU 105 determines whether or not the image forming apparatus is powered on (step S1). It is in a standby state until the power is turned on.

  If the CPU 105 determines in step S1 that the power is turned on, it next starts inter-motor communication (step S2).

  Next, the CPU 105 confirms the number of motors (step S3). In this example, since the main motor and the sub motor are provided, it can be determined that the number of motors is two.

  Next, the CPU 105 sets a phase shift amount according to the number of motors (step S4).

Specifically, the phase shift amount is set to 1 / N cycle according to the number of motors (N).
Next, an instruction to set the phase shift amount is output (step S5).

  In this example, since there are two main side motors and sub side motors, the phase shift amount is set to a half cycle. Therefore, the clock phase control unit 260 shifts the half-cycle phase of either the PWM signal generation unit 210 or 310 with respect to one of the PWM signal generation units 210 and 310 in accordance with an instruction from the CPU 105 according to the instruction from the CPU 105. Output. When the number of motors is N, the phase shift amount is set to 1 / N cycle.

(Embodiment 2)
In the first embodiment, the case where the clock phase control unit 260 outputs PWM clocks having different phases to the PWM signal generation units 210 and 310 has been described.

  On the other hand, when the PWM clock is input to the PWM signal generators 210 and 310 to generate the PWM signal, the duty ratio of the PWM signal having a predetermined cycle is set to a high value in the startup sequence. Here, the duty ratio of the PWM signal means the ratio of the on period in the total period (one cycle) of the on period and off period signals. Specifically, if the duty ratio is ½, the on period and the off period in one cycle are the same length. Here, a high value of the duty ratio indicates that the duty ratio is 1/2 or more.

  In the start-up sequence, since the desired target rotational speed has not been reached at the first rise, the duty ratio is approximately 1 so that the PWM signal generator 210 is driven at full power by the control from the motor drive controller 205. A PWM signal with a value close to is generated.

  Therefore, even when the phase of the PWM clock is shifted by half a cycle in the first embodiment, the duty period of the PWM signal in the PWM signal generator 210 is high, so that the ON periods overlap each other. Become.

FIG. 8 is a schematic diagram of PWM signal waveforms generated by the main-side and sub-side motors.
As shown in FIG. 8, when the chopping cycle is a predetermined cycle, the on-period of the PWM signal overlaps between the main-side motor and the sub-side motor.

  That is, when the duty ratio is high, the PWM signals in the PWM signal generators 210 and 310 have current waveforms that are shifted from each other by a half cycle, but the ON periods overlap.

  In the second embodiment of the present invention, a method for further reducing the total peak current value of the chopping current waveform as compared with the first embodiment will be described.

  FIG. 9 is a diagram illustrating a configuration in which motor units 200 and 300 are controlled by CPU 105 # in controller 100 according to the second embodiment of the present invention.

  Referring to FIG. 9, CPU 105 # in controller 100 is different from the configuration in FIG. 1 in that it instructs PWM signal generators 210 # and 310 # to set an upper limit duty. Since the other points are the same as those described in FIG. 1, detailed description thereof will not be repeated.

  FIG. 10 is a flowchart illustrating a setting instruction from the CPU to the motor unit according to the second embodiment of the present invention.

  Referring to FIG. 10, CPU 105 # determines whether the image forming apparatus is powered on (step S1). It is in a standby state until the power is turned on.

  If the CPU 105 # determines in step S1 that the power is turned on, it next starts inter-motor communication (step S2).

  Then, CPU 105 # confirms the number of motors (step S3). In this example, since the main side motor and the sub side motor are provided, it can be determined that the number of motors is two.

  Next, CPU 105 # sets a phase shift amount according to the number of motors (step S4).

  In this example, the phase shift amount is set to 1 / N cycle, that is, in this example, 1/2 cycle, according to the number of motors.

  Next, CPU 105 # sets an upper limit duty in accordance with the number of motors (step S6).

  Specifically, the upper limit duty is set to 1 / N according to the number of motors. In this example, it is set to 1/2.

  Next, CPU 105 # outputs an instruction to set a phase shift amount to clock phase controller 260 (step S7).

  Next, CPU 105 # outputs an instruction to set an upper limit duty to PWM signal generation units 210 # and 310 # (step S8).

Then, the process ends (END).
FIG. 11 is a schematic diagram of PWM signal waveforms generated by the main-side and sub-side motors according to the second embodiment of the present invention.

  As shown in FIG. 11, since the upper limit duty is set when the chopping cycle is a predetermined cycle, the main motor and the sub motor do not overlap with each other.

  This is because the PWM clock shifted by 1/2 cycle is input between the main side motor and the sub side motor, and the upper limit duty is set to 1/2, so even if the PWM signal supplied to the main side motor is the upper limit duty Even when the on period of the PWM signal is cut according to the setting of the PWM signal, the on period of the PWM signal supplied to the sub-side motor is also overlapped because the on period of the PWM signal is cut according to the setting of the upper limit duty There is nothing.

  FIG. 12 is a diagram illustrating chopping current waveforms in the main-side and sub-side motors according to the second embodiment of the present invention.

  As shown in FIG. 12, as the chopping current waveform, the phase of the lower main-side chopping current waveform and the upper sub-side chopping current waveform are shifted by a half cycle. That is, since the main-side chopping current waveform and the sub-side chopping current waveform are current waveforms that are shifted from each other by a half cycle, the peak values of the chopping current pulses are different from each other.

  Further, as described above, the upper limit duty of the PWM signal is set to ½. That is, since the ON periods of the PWM signals do not overlap each other, the chopping current pulses do not overlap with each other in the chopping current waveform on the main side and the chopping current waveform on the sub side. Yes.

  FIG. 13 is a current waveform diagram of the total chopping currents of the main-side and sub-side motors according to the second embodiment of the present invention.

  Referring to FIG. 13, the total peak current value of the main-side and sub-side chopping current waveforms is set to be approximately the same as the peak current value when one of the motors is driven. In this example, it is set to 6A or less.

  Therefore, the method according to the second embodiment of the present invention makes it possible to reduce the peak current value and simultaneously execute the start-up sequence of the main side motor and the sub side motor as described in FIG. Therefore, it is possible to reduce the total motor startup time until the startup sequence of the main motor and the sub motor is completed.

  Furthermore, since the peak current value can be reduced, the power supply device can be downsized and the circuit cost can be reduced without increasing the power supply capacity.

  In this example, the number of motors is set to two. However, the number of motors is not particularly limited, and a plurality of motors may be used. For example, when there are three units, the phase of the PWM clock is shifted by 1/3 period and output to the PWM signal generator corresponding to each motor, and the upper limit duty is set to 1/3 in the PWM signal generator. By doing so, it is possible to set so that the ON periods of the PWM signals do not overlap. As a result, the chopping current waveforms in the motors can be prevented from overlapping each other, so that the total peak current value can be reduced and a high-speed startup sequence can be executed.

  In the present example, when the number of motors is N, the PWM clock shifted by 1 / N period is output to the PWM signal generation unit and the upper limit duty is set to 1 / N. There is also a possibility that the ON periods of the PWM signals overlap due to delay or the like. Therefore, it is possible to adjust the upper limit duty ((1 / N) −α: α <1) so as to provide a predetermined interval (margin) between the ON periods of the PWM signals.

  In this example, a tandem digital color copying machine has been described. However, the present invention is not limited to a copying machine as a kind of image forming apparatus, and can be similarly applied to a facsimile or MFP.

  Note that it is also possible to provide a program that causes a computer to function for each unit that controls the image forming apparatus, and executes control as described in the above flow. Such a program is stored in a computer-readable recording medium such as a flexible disk attached to the computer, a CD-ROM (Compact Disk-Read Only Memory), a ROM (Read Only Memory), a RAM (Random Access Memory), and a memory card. And can be provided as a program product. Alternatively, the program can be provided by being recorded on a recording medium such as a hard disk built in the computer. A program can also be provided by downloading via a network.

  Of the program modules provided as part of the computer operating system (OS), necessary modules may be called at a predetermined timing and executed in a predetermined arrangement. In that case, the program itself does not include the module, and the process is executed in cooperation with the OS. A program that does not include such a module can also be included in the program according to the present invention.

  The program may be provided by being incorporated in a part of another program. Even in this case, the program itself does not include the module included in the other program, and the process is executed in cooperation with the other program. Such a program incorporated in another program can also be included in the program according to the present invention.

  The provided program product is installed in a program storage unit such as a hard disk and executed. The program product includes the program itself and a recording medium on which the program is recorded.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

2 is a schematic cross-sectional view showing an outline of a hardware configuration of copying machine 1 according to the embodiment of the present invention. FIG. It is a figure explaining the structure by which the motor parts 200 and 300 are controlled by CPU105 in the controller 100. FIG. It is a figure explaining the PWM clock according to the embodiment of the present invention. It is a figure explaining the PWM chopping current waveform according to Embodiment 1 of the present invention. It is a current waveform diagram of the total of the chopping currents of the main-side and sub-side motors according to the first embodiment of the present invention. It is a figure explaining the case where the starting sequence of a main side motor and a sub side motor is performed simultaneously. It is a flowchart explaining the setting instruction | indication from the CPU according to Embodiment 1 of this invention to a motor part. It is a schematic diagram of the PWM signal waveform produced | generated by the main side and sub side motor. It is a figure explaining the structure by which the motor parts 200 and 300 are controlled by CPU105 # in the controller 100 according to Embodiment 2 of this invention. It is a flowchart explaining the setting instruction | indication from the CPU according to Embodiment 2 of this invention to a motor part. It is a schematic diagram of the PWM signal waveform produced | generated by the main side and sub side motor according to Embodiment 2 of this invention. It is a figure explaining the chopping current waveform in the main side and sub side according to Embodiment 2 of this invention. It is a current waveform figure of the sum total of the chopping current of the main side motor and sub side motor according to Embodiment 2 of this invention. It is a current wave form diagram of chopping current at the time of performing starting control of a plurality of motors simultaneously. It is a current waveform diagram of the total of the chopping currents of the main side and sub side motors. It is a figure explaining the system which shifts starting timing with a main side motor and a sub side motor.

Explanation of symbols

  100 controller, 105, 105 # CPU, 110 ROM, 115 RAM, 200, 300 motor unit, 205, 305 motor drive control unit, 210, 210 #, 310, 310 # PWM signal generation unit, 250 PWM clock oscillation unit, 260 Clock phase control unit, F1, F2 FG sensor, IV1, IV2 inverter, M1, M2 motor.

Claims (5)

Developing means for forming an electrostatic latent image for transfer to a sheet;
Conveying means for conveying paper;
A plurality of motors for driving at least one of the developing means and the conveying means;
A plurality of motor control units provided corresponding to the plurality of motors, each including a control signal generation unit that generates a motor drive control signal for operating the corresponding motor in accordance with an input of a clock frequency of a predetermined period When,
A clock oscillator that oscillates the clock frequency of the predetermined period;
An image forming apparatus comprising: a clock phase control unit that receives the clock frequency of the predetermined cycle oscillated from the clock oscillator and outputs the clock frequency of the predetermined cycle having a different phase to each of the control signal generation units. . The control signal generation unit generates a motor drive control signal having a predetermined cycle including an on period in which current is supplied to the corresponding motor and an off period in which supply of current is stopped in accordance with an input of the clock frequency of the predetermined cycle. And
The image forming apparatus according to claim 1, wherein the control signal generation unit sets a duty ratio of the ON period in the predetermined cycle to be a predetermined value or less.   The image forming apparatus according to claim 2, wherein when the plurality of motors is N, the predetermined value is set to 1 / N.   The image forming apparatus according to claim 1, wherein the clock oscillator is a single oscillator.   5. The clock phase control unit according to claim 1, wherein when the plurality of motors is N, the clock phase control unit outputs the predetermined clock frequency whose phase is shifted by 1 / N period to each of the signal generation units. The image forming apparatus according to claim 1.

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