JP2003023789A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller which controls a plurality of motors so as to make them function with mutual linkages and which is small in size and low in cost. SOLUTION: A frequency of a primary clock signal f1, oscillated by a quartz oscillator 15, is divided by counters 102 and 103 to generate a plurality of clock signals. According to a selection signal SEL1 from a main controller, one among the plurality of clock signals is selectively outputted from a multiplexer 104 as a reference clock signal CLK1 which is inputted to a motor drive unit 10. A motor M1 is turned at a constant revolution by PLL control, according to the reference clock signal CLK1, while the clock signal CLK1 and a clock signal CLK4, selected by a multiplexer 105 are supplied to other motor boards 2, 3, and 4 and are used as reference clock signals of motors mounted on the boards.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device including a plurality of motor units.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine and a laser printer is provided with a plurality of rotating mechanisms such as a paper feeding / discharging device and a photosensitive drum, and these mechanisms rotate in association with each other. It realizes predetermined operations such as paper feeding and printing. And with such a device,
In many cases, in order to reduce the number of expensive motors used and reduce costs, the rotational force of one motor is transmitted to multiple rotary shafts using mechanical means such as gears, belts and clutch mechanisms. I am using it.

[0003]

On the other hand, on the other hand, it is required to drive each rotary shaft by an individual motor in order to realize a complicated function and further improve the accuracy. In this case, it is important how accurately each motor works together. This is because if the interlocking precision of the motors is not good, for example, the timing of feeding the paper and the timing of printing will not match, and the printing position on the paper will shift, or paper jams will occur. In order to meet such a demand, the control device becomes complicated by providing a high-precision crystal oscillator in the control circuit of each motor to precisely control the rotation speed. As a result, the number of parts and the space occupied by the parts increase, resulting in an increase in size of the product and an increase in cost.

The present invention has been made in view of the above problems, and an object thereof is to provide a small-sized and low-cost control device in a motor control device in which a plurality of motors function in conjunction with each other.

[0005]

According to a first aspect of the present invention, in order to achieve the above object, a clock generator for generating a primary clock having a first frequency, and 1 / n of the primary clock are provided. (N is a natural number of 1 or more) and at least 1 is selected from a frequency dividing unit that outputs at least two types of secondary clocks having different frequencies, and each of the secondary clocks output from the frequency dividing unit. And a clock generating unit configured to select and output one of the secondary clocks, and each of the driving units uses one of the secondary clocks selected by the selecting unit as the reference clock. I am trying.

In the invention thus constructed, a plurality of motors constituting the device are rotationally driven based on a reference clock obtained by dividing the same primary clock.
It becomes easy to synchronize each motor. Since only one clock generator is required for a plurality of motors, the device can be downsized and the cost can be reduced.

Since this clock generating unit can be constructed by combining basic digital circuits such as a counter and a multiplexer, by realizing it with a small gate array or a custom IC, the clock can be further miniaturized. It is possible to improve mass productivity.

Further, by reducing the number of clock generation circuits that handle high-frequency signals and reducing the area thereof, the emission of high-frequency noise from the device can be reduced.

Here, there are various cases in which the number of rotations of the plurality of motors constituting the apparatus may be the same, some of them may be the same and the others may be different, or all of them may be different.
Either case can be dealt with by increasing or decreasing the frequency division ratio and the number of output clocks from the selection unit according to the specifications of the device. Also, by changing the reference clock frequency of one motor by switching the clock in the selection unit,
It is possible to operate one motor by switching to several different rotation speeds.

In any case, it is desirable that the frequency of the primary clock generated by the clock generator is a common multiple of all the frequencies required for the reference clock. The reason is that by doing so, all necessary reference clocks can be generated only by dividing the frequency of a single primary clock.

However, depending on the device, there is a case in which the required reference clocks cannot be generated from a single primary clock because the required reference clocks are not in a simple multiple relationship.
In such a case, it is necessary to provide a plurality of clock generation units in one device. Even in this case, the present invention is applied to the extent possible, and the number of clock generation circuits is small and the device is small in size.
Cost reduction is possible.

A crystal oscillator can be used as a source of the primary clock of the present invention (claim 2).
By doing so, it is possible to generate a clock with a stable frequency based on the oscillation of the crystal and improve the rotation accuracy of the motor. Moreover, by minimizing the number of crystal oscillators used, the cost rises. Can be suppressed.

Further, the clock generator may be incorporated in any one of the plurality of motor units (claim 3). In the invention thus configured,
It is possible to downsize the clock generation unit and mount it on the circuit board that constitutes the motor unit, specifically, the drive unit. By doing so, a circuit board for mounting the clock generation unit is separately provided. Since it is not necessary to provide the device, the size and cost of the device can be further reduced. Also, by disposing the clock generation circuit in the vicinity of the motor, it is possible to reduce the routing of high frequency signals and reduce the emission of high frequency noise.

The invention according to claim 4 is characterized in that the motor is a DC brushless motor. In the invention configured as described above, a small and responsive DC brushless motor is used as a driving motor for a mechanical device, and the reference clock of each motor is generated from a single clock source. Also, the circuit portion can be configured to be small and lightweight, and a small and highly accurate mechanical device can be configured at low cost.

According to a fifth aspect of the present invention, the selection section selects at least one of the secondary clocks output from the frequency division section based on a selection control command given from the outside. It is characterized by selecting.

In the invention thus constructed, a clock having a frequency required as a reference clock for each motor is prepared in advance by dividing the primary clock, and these are appropriately adjusted by a selection control command from the outside. By switching and using the reference clock of each motor, it is possible to change the rotation speed of each motor at any time and realize a complicated operation. Moreover, since the clocks that are supplied to each motor unit are switched by the clock generator, there is no need for wiring to supply multiple clock signals and their switching control signals to each motor unit. Can be reduced and the device can be configured to be lightweight and low cost.

According to a sixth aspect of the present invention, the plurality of motor units are mounted on an image forming apparatus such as a copying machine or a laser printer, and a control unit for controlling the operation of the image forming apparatus includes the image forming apparatus. The selection control command is output according to the operation mode of the forming apparatus.

According to the invention thus constructed, in the image forming apparatus, a plurality of motors for driving, for example, a paper feeding mechanism, a photosensitive drum, etc. can be accurately synchronized and operated, and a paper jam or a print position deviation can be caused. It is possible to reduce troubles such as Furthermore, since the reference clock of each motor can be changed by a selection control command from the control unit of the image forming apparatus, it is possible to change the number of rotations while maintaining synchronization between the motors according to the operation mode of the apparatus. it can. Therefore, for example, it is possible to control the paper feed speed to be slower than usual in order to perform high-definition printing, and it is possible to improve print quality.

Since the clock generation circuit for controlling these motors can be realized by a small-scale circuit, the size and cost of the device can be reduced.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a laser beam printer (LBP) will be described with reference to FIGS. FIG. 1 is a sectional view showing the outline of the engine section of this printer, and FIG. 2 is a block diagram showing the electrical configuration of this printer. 3 and 4 are block diagrams each showing a circuit configuration of one of the motor boards mounted on the printer.

As shown in FIG. 1 and the following, this printer is a device for performing printing by electrophotography, and performs printing by fixing toner on paper based on print data.

In this printer, when a print command and print data are input from a host computer (not shown), the main controller 5 shown in FIG. 2 performs the following five steps (1) to (5). Along with this, predetermined control is performed on each unit of the apparatus shown in FIGS. 1 and 2, and printing is performed on a sheet. (1) Charging Step In this step, the surface of the photosensitive drum DR having the optical semiconductor layer formed on its surface is uniformly charged so that the toner T can be attached thereto. Specifically, a negative voltage is applied to the charging roller CR composed of a conductive elastic body, and the surface of the photosensitive drum DR is charged to a negative potential by rotating the charging roller CR while contacting the photosensitive drum DR. (2) Exposure Step In this step, the surface of the charged photosensitive drum DR is irradiated with the laser light L scanned by the laser light source 61 and the reflection mirror 62 according to the print data.
When the surface of the photosensitive drum DR is irradiated with the light L, a charge is generated by the photoelectric effect, and the charge charged in step (1) is neutralized. On the other hand, electric charges due to charging remain in the non-irradiated portion.

As will be described later, the toner T adheres to the uncharged portion due to the neutralization of the electric charge, but the toner T does not adhere to the charged portion. As described above, by irradiating the surface of the photosensitive drum DR with the laser light L only on the portion where the dots of the toner T should be formed according to the print data, the dots should be formed on the surface of the photosensitive drum DR. An electrostatic pattern (electrostatic latent image) is formed in which a portion is not charged and the other portions are negatively charged. (3) Developing Step In this step, the toner T is attached to the non-charged portion of the photosensitive drum DR. Specifically, the toner T, which is negatively charged, is transferred to the photosensitive drum DR by the developing cylinder DS.
Supply near. At this time, the toner T is applied to the non-charged portion (the portion irradiated with light) on the surface of the photosensitive drum DR.
However, the toner T does not adhere to the charged portion due to the repulsion between the negative charges. In this way, the electrostatic latent image is converted into a monochrome image depending on the presence or absence of the toner T adhered, and the photosensitive drum D
It is visualized on the surface of R. (4) Transfer Step In this step, from the paper tray PT to the paper feed roller P
The paper P supplied by the H and the guide G is pressed against the photosensitive drum DR by the transfer roller TR to be brought into close contact therewith, and a positive potential is applied from the back side of the paper P (the lower side in FIG. 1) to the surface of the photosensitive drum DR. The attached toner image is transferred to the paper P. (5) Fixing Step The toner T transferred onto the paper P is simply attached to the paper P due to static electricity and easily peels off.
Therefore, the paper P is passed between the heated fixing roller FR and the pressure roller PR, and the toner T is fixed on the paper P by applying heat and pressure. Is discharged to.

In the printer of this embodiment, the charging roller CR, the photosensitive drum DR, the developing cylinder DS and the toner T among the above-mentioned units are built in a cartridge CT which is detachably attached to the apparatus main body. Cage,
The cartridge CT can be exchanged according to these consumption conditions.

Next, the electrical construction of this printer will be described with reference to FIG. As shown in FIG. 2, the printer includes an optical system 6 including a laser light source 61 and a control circuit (not shown) for the laser light source 61, an interface section 7 for receiving print data and a user operation from a host computer, and an operation state of the apparatus. It is composed of a display section 8 for notifying the user, motor boards 1, 2, 3, 4 and a main controller 5 for controlling each section of these devices.

Motors M1, M2, M3, and M4 are mounted on the motor boards 1, 2, 3, and 4, respectively. The motor M1 is connected to the paper feed roller PH shown in FIG. 1, the motor M2 is connected to the photosensitive drum DR, the motor M3 is connected to the pressure roller PR, and the motor M4 is connected to the developing cylinder DS. Each is configured to be rotationally driven based on a control command.

The motor board 1 on which the motor M1 is mounted is connected to the main controller 5 by the wiring 16. The wiring 16 is used for the control signal from the main controller 5 to each motor and the information on the operating condition of the motor.
Has been transmitted through. This wiring 16 is connected to the motor board 1
16a provided on the main controller 5
And a wire harness 16c for connecting them to each other.

Further, the motor board 1 has wirings 17, 18
And 19 are connected to the motor boards 2, 3 and 4, respectively, and control signals to the motors M2, M3 and M4 mounted on the respective boards and information relating to the operating condition from each motor are exchanged. There is.

As described above, in this printer, the four motors M1 to M4 are controlled by the main controller 5. Of the motors M1 to M4 and their control circuits, the motor boards 1 to 4 are mounted. Only the motor board 1 is directly connected to the main controller 5, and the others are connected to the main controller 5 via the motor board 1.

As shown in FIG. 3, the motor board 1 includes a connector 16a and a wire harness 16 connected thereto.
It is connected to a connector 16b provided in the main controller 5 via c, and exchanges each signal shown in FIG. 3 with the main controller 5. The function of each signal will be described later, but the outline is as follows: ERR1 ... Indicates that the motor M1 is in an asynchronous state (asynchronous = H level) ERR24 ... Any of the motors M2, M3, and M4 Indicates an asynchronous state (asynchronous = H level) STARTn ... Start signal of motor Mn (n = 1,
2, 3, 4) SEL4A, SEL4B ... Reference clock selection signals for the motor M4 SEL1A, SEL1B ... Reference clock selection signals for the motors M1, M2, M3 Here, the "asynchronous" state of each motor means that the motor is the reference clock signal. Represents a state in which the motor is not rotating at a predetermined rotation speed determined by.

Further, the motor board 1 is provided with connectors 17a, 18 for connecting to the motor boards 2, 3 and 4, respectively.
a and 19a are provided.

Next, the clock generator 100 provided on the motor board 1 will be described. This clock generator 1
00 is a primary clock generator (crystal oscillator 15, inverter 101), frequency divider (counters 102 and 103)
And a selection unit (multiplexers 104 and 105).

In the clock generator 100, the crystal oscillator 15 connected between the input and output terminals of the inverter 101.
Generates a primary clock having the frequency f1 and this primary clock is input to the counters 102 and 103. The counter 102 multiplies this primary clock by 1,
Divide by 1/2, 1/4, and 1/8 and output. On the other hand, the counter 103 is 1/3 times or 1 / times the primary clock.
Divide by 6 and output. In the following, the frequency of the clock obtained by dividing the primary clock by 1 / n is fn.
(For example, the clock frequency divided by 1/3 is f
3).

Of the six types of clocks thus generated having different frequencies (f1, f2, f3, f4, f6, f8), clocks having frequencies f1, f2, f3, f4 are input to the multiplexer 104. Therefore, the multiplexer 104 outputs one of these four clocks based on a 2-bit clock selection signal (SEL1A and SEL1B) input from the main controller 5 via the connector 16a according to the operation mode of the device. It is selected and output as the reference clock CLK1.

On the other hand, in the multiplexer 105, f2,
Clocks having frequencies of f4, f6, and f8 are input, and the multiplexer 105 outputs these four signals based on a 2-bit selection signal (SEL4A and SEL4B) input from the main controller 5 via the connector 16a.
One of the two clocks is selected as the reference clock CLK4 and output.

Next, the motor drive unit 10 provided on the motor board 1 will be described. The motor drive unit 10 includes a DC brushless motor M1 and its control circuit (driver 1
1, a PLL circuit 12). This control circuit performs PLL (phase synchronization) control on the motor M1. That is, the motor M1 is provided with a frequency generator (not shown) that generates a pulse signal FG synchronized with the rotation speed of the motor M1, and the PLL circuit 12 causes the frequency of the pulse signal FG and the frequency of the reference clock CLK1. The control voltage Vp proportional to the difference between Then, based on this control voltage Vp, the driver 11 causes the motor M1 to
The drive current to is adjusted.

As described above, the motor M1 has the pulse signal F
It is controlled so that it decelerates when the frequency of G is higher than the reference clock CLK1 and accelerates it when the frequency of G is higher. In this way, the motor M1 rotates at a constant speed in synchronization with the reference clock CLK1.

The start / stop of the motor M1 is started by the start signal STAR from the main controller 5.
It is controlled by T1. Then, the PLL circuit 12
Outputs an ERR1 signal that becomes H level when the pulse signal FG and the reference clock CLK1 do not match as a result of comparison, that is, the rotation speed of the motor M1 is different from the set value. The ERR1 signal is input to the main controller 5 via the connector 16a, and the main controller 5 determines whether the motor M1 is rotating at a predetermined rotation speed.

In this way, the motor M1 receives a control signal from the main controller 5 (regarding the start and rotation speed).
The rotation is controlled by.

Further, the motor board 1 is connected to the motor board 2 via wiring 17 (a connector 17a of the motor board 1, a connector 17b provided on the motor board 2 and a wire harness connecting them). And
From the motor board 1 to the motor board 2, a motor M2 start signal START2 from the main controller 5 and a clock CLK1 output from the motor board 1 in response to a selection signal from the main controller 5 are supplied to the motor M.
While being output as the reference clock CLK2 of 2, the ERR2 signal that is at the H level is input from the motor board 2 when the rotation speed of the motor M2 is different from the set value.

This motor board 2 is, as shown in FIG.
It has the same configuration as the motor drive unit 10 of the motor board 1, and is composed of a DC brushless motor M2 and its control circuit (driver 21, PLL circuit 22).

Then, by the start signal START2 and the reference clock CLK2 (in this embodiment, the same clock as CLK1) input from the motor board 1,
The rotation of the motor M2 is controlled in the same manner as the motor drive unit 10.

The motor boards 3 and 4 connected to the motor board 1 also have the same structure as the motor board 2, and the rotation of the motors M3 and M4 is controlled based on a control signal from the main controller 5. However, as shown in FIG. 3, the same reference clock CLK1 as the motor M1 is input to the motor boards 2 and 3, whereas the reference clock CLK4 output from the multiplexer 105 is input to the motor board 4. It has been entered.

That is, in this printer, the motor M
1, M2 and M3 synchronously rotate at a rotation speed based on the reference clock CLK1 selected by the multiplexer 104 based on the selection signals SEL1A and SEL1B from the main controller 5. This is because, as shown in FIG. 1, since the paper P is sent from the paper feed roller PH via the transfer roller TR and the fixing roller FR, the paper P cannot be smoothly sent unless their rotation speeds match. This is because there is a risk of paper jams and deterioration of print quality. on the other hand,
The motor M4 is a selection signal SE from the main controller 5.
It rotates at a rotation speed based on the reference clock CLK4 selected by the multiplexer 105 based on L4A and SEL4B. All of these reference clocks are output from the clock generation unit of the motor board 1.

On the other hand, the error signals ERR2 and ERR from the respective motors indicating whether the motors M2 to M4 are rotating in synchronization with the reference clock CLK1 or CLK4.
3 and ERR4 are input to the motor board 1 via the wirings 17, 18, and 19, and these signals are supplied to the OR circuit 10.
It has been entered in 6. The logical sum output ERR24 of these signals is passed through the wiring 16 to the main controller 5
Have been sent to. That is, when the rotation speed of at least one of the motors M2, M3, and M4 is different from the predetermined value, the error signal ERR from the board on which the motor is mounted becomes H level, and the logical sum signal ERR24 becomes H, and the main controller becomes. 5 is taken and measures such as cutting off the motor current are taken. Thus the main controller 5
Controls the operation of the entire apparatus while always grasping the rotation states of the motors M1 to M4.

As described above, in the printer of this embodiment, the logical sum signal ERR24 of the error signals from the motors M2, M3, and M4 is returned to the main controller 5, so that the main controller 5 and the motor board 1 are separated from each other. It is configured so that the abnormal operation of each motor can be dealt with surely and promptly while reducing the number of wirings.

Of the above construction, the inverter 101,
The counters 102 and 103, the multiplexers 104 and 105, and the OR circuit 106 are combined into one gate array I.
Built into C. This is because these are circuits that can be realized with basic gate circuits or a combination thereof, and these can be implemented in a gate array or PLD (Programm).
This is because it is possible to reduce the number of parts and downsize the device by integrating them into a single chip as an able logic device) or a custom IC. Of course, these may be configured by individual digital ICs, but especially when mass-producing the device, the cost merit by making these ICs becomes great.

In the printer thus constructed,
When a print command is input from the host computer via the interface unit 7, the main controller 5 determines the operation mode of the apparatus according to the command. And
The selection signals (SEL1A, SEL1B, SEL4) for determining the number of rotations of each motor according to the operation mode.
A, SEL4B) are set and output to the motor substrate 1.
As a result, each of the motors M1 to M1
The frequency of the reference clock output to M4 is determined.

Then, the main controller 5 appropriately sends a start signal STAR to each of the motors M1 to M4 in accordance with the progress of the process along the above steps (1) to (5).
The optical system 6 is output according to the print data while outputting Tn.
Is controlled to carry out the printing process.

Further, the main controller 5 selects each selection signal (SEL1) for changing the rotation speed as required.
A to SEL4B) to change the rotation speed of each motor to reduce the rotation speed of each motor to 1/2 of the normal print mode to perform high-definition printing, or change the rotation speed of each motor. It is possible to realize various operation modes such as high-speed printing by doubling the normal print mode.

If any motor continues to be out of synchronization for a certain period of time due to a paper jam or other trouble, the main controller 5 stops all the motors and interrupts the printing process. Furthermore, a message indicating that an operation abnormality has occurred is displayed on the display unit 8 to notify the user,
The user is urged to take action to solve the trouble such as taking out the paper P.

As described above, in the printer of this embodiment, all the clocks that serve as the reference for the rotation speeds of the four motors M1 to M4 are generated by the clock generation unit 100 provided on the motor board 1. The motors M1 to M4 can be easily synchronized. And other motor board 2
4 does not need to be provided with a clock circuit, the other motor boards 2 to 4 can be made small, and the wire harness connecting the boards can be reduced, so that the apparatus can be made small and low cost. . Furthermore, since the digital circuit including the main part of the clock generation unit 100 is realized by one gate array IC, the number of components and the board size of the motor board 1 can be minimized.

Further, by not providing a large number of clock sources and reducing the routing of high frequency clock signals, it is possible to reduce the emission of high frequency noise from the circuit.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, an example in which four motors M1 to M4 are used and M1 to M3 among them are rotated at the same number of revolutions has been described, but the number of motors is not limited to this. However, other numbers may be used. In addition, the combination of the rotation speeds of the motors may be, for example, a configuration in which the motors rotate at different rotation speeds.

Further, in the above-described embodiment, the primary clock of the crystal oscillator 15 is frequency-divided to be 1 ×, 1/2 ×, 1/3.
Six types of clocks are generated, namely, 1/4 times, 1/4 times, 1/8 times, but the clock division ratio is not limited to this, and frequency division / multiplication can be combined appropriately. A clock having a required frequency may be generated. And
For example, it is possible to use two crystal oscillators and output clocks that are not in a multiple relationship with each other. Even in this case, by making the clock source common in a possible range, it is possible to reduce the number of components, downsize the device, and reduce the cost.

Further, in the above-mentioned embodiment, the case where the DC brushless motor is used as the motor to be controlled has been described. However, the present invention is applied to an apparatus using a DC motor with brush or a stepping motor in addition to this. Can also be applied.

In the above description, the case where the present invention is applied to a monochrome laser beam printer has been described. However, the present invention is not limited to this, and other examples such as a copying machine, a facsimile receiver, a color printer, etc. It can also be applied to an image forming apparatus.

Further, even in the case of a device other than the image forming device, in a device having at least two motors and operating in cooperation with each other, such as a mechatronics device such as an industrial robot, The present invention can be applied to a reference clock generation circuit.

[0060]

As described above, according to the first aspect of the present invention, the reference clock for controlling the plurality of motors constituting the device can be generated by the single clock generation circuit. The synchronization between the motors is facilitated, and the device can be configured in a small size and at low cost. Furthermore, high-frequency noise can be reduced by reducing the number of high-frequency circuits and making them small.

Moreover, since the clock generation section can be realized by a combination of basic digital circuits, the apparatus can be further miniaturized by using these as a gate array IC or a custom IC, and the configuration is suitable for mass production. be able to.

According to the second aspect of the present invention, by using the clock having the high frequency stability by the crystal oscillator, it becomes possible to drive the motor with high accuracy. Moreover, it is possible to suppress an increase in cost by reducing the number of clock generation circuits.

According to the third aspect of the invention, by incorporating the clock circuit in one of the plurality of motor units, the number of parts and wiring between the units can be reduced, and the device can be made compact. And cost can be reduced.
Further, by minimizing the routing of high frequency signals, it is possible to suppress the emission of high frequency noise.

Further, according to the invention described in claim 4, since the DC brushless motors which are small in size and have good responsiveness are used, and the reference clock of each motor is generated from a single clock source, the device is It can be constructed in a small size, light weight, and low cost.

Further, according to the invention described in claim 5, it is possible to appropriately switch the rotation speed of each motor to perform a complicated operation, but in this case as well, a plurality of clocks and clocks are provided to each motor unit. It is not necessary to route the signal line for the switching.

According to the sixth aspect of the present invention, in the image forming apparatus that operates a plurality of motors in conjunction with each other, it is complicated to change the number of rotations while maintaining the synchronization between the motors. The operation can be realized. Moreover, by configuring the clock generating circuit in a small scale, it is possible to reduce the size and cost of the image forming apparatus.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an engine unit of a laser beam printer according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the printer of this embodiment.

FIG. 3 is a block diagram showing a circuit configuration of one motor board of the printer of this embodiment.

FIG. 4 is a block diagram showing a circuit configuration of another motor substrate of the printer of this embodiment.

[Explanation of symbols]

1, 2, 3, 4 Motor board (motor unit) 5 Main controller (control unit) 10 Motor drive unit 11, 21 Driver 12, 22 PLL circuit 15 Crystal oscillator 16, 17, 18, 19 Wiring 16a, 17a, 18a , 19a Connector 16c Wire harness 61 Laser light source 100 Clock generator 102, 103 Counter (divider) 104, 105 Multiplexer (selector) CR Charging roller DR Photosensitive drum DS Developing cylinder FR Fixing roller M1, M2, M3, M4 Motor (DC brushless motor) P Paper PH Paper feed roller PR Pressure roller TR Transfer roller

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C480 CB02 EA02 EA22 EA26                 2H027 ED02 ED08 ED17 ED25 EE01                       EE02 EE04 ZA09                 5H560 AA10 BB04 BB12 CC03 DB03                       EB01 GG03 SS01 TT02 TT07                       TT15 XA06                 5H572 AA13 DD05 EE04 GG06 HA07                       HB07 HC07 JJ03 JJ13 KK04                       LL09

Claims (6)

[Claims] 1. A motor control device comprising a plurality of motor units each comprising a motor and a drive unit for rotationally driving the motor so that the rotation speed of the motor is proportional to the frequency of a reference clock given from the outside. A clock generation unit for generating a primary clock having a frequency of, and outputting at least two types of secondary clocks having different frequencies by dividing the primary clock into 1 / n (n is a natural number of 1 or more) A clock generator that selects and outputs at least one of the secondary clocks output from the frequency divider. Each of the drivers includes: The motor control device, wherein one of the secondary clocks selected by the selection unit is used as the reference clock. 2. The motor control device according to claim 1, wherein the clock generator generates the primary clock based on oscillation of a crystal oscillator. 3. The motor control device according to claim 1, wherein the clock generation unit is incorporated in any one of the motor units. 4. The motor control device according to claim 1, wherein the motor is a DC brushless motor. 5. The selection unit selects at least one of the secondary clocks output from the frequency dividing unit based on a selection control command given from the outside. The motor control device according to any one of 1 to 4. 6. The plurality of motor units are mounted on an image forming apparatus such as a copying machine or a laser printer, and a control unit for controlling the operation of the image forming apparatus is configured to operate in accordance with an operation mode of the image forming apparatus. The motor control device according to claim 5, which outputs a selection control command.