JP2001339978A - Rotor control device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress wear and deterioration of a rotor of a light-sensitive drum and the like by controlling the relative speed of each motor to minimum when starting or speed-lowering each motor without enlarging its device and incurring increase in cost. SOLUTION: A motor control unit 14 is provided for minimizing the relative speed of each motor when raising or lowering speed of motors 6a-6d which drive respectively light-sensitive drums 1a-1d and a carrier belt 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control device for controlling a plurality of rotating members that come into contact with each other, and more particularly to an image forming apparatus including a photosensitive drum as a plurality of rotating members and a rotating member that contacts the photosensitive drum. It is.

[0002]

2. Description of the Related Art FIG. 12 shows four colors, that is, yellow Y,
FIG. 1 shows a color image forming apparatus provided with magenta M, cyan C, and black K image forming units.
01 is a photosensitive drum for forming an electrostatic latent image (subscripts a, b,
c and d are for black K, cyan C, magenta M and yellow Y, respectively), 106a, 106b, 106c,
106d is each photosensitive drum 101a, 101b, 101
c, 101d.

[0003] Reference numeral 102 denotes a laser scanner that performs exposure in accordance with an image signal to form an electrostatic latent image on the photosensitive drum 101 (subscripts a, b, c, and d denote respective photosensitive drums 101 a, 101 d).
b, 101c, and 101d), 103 is an endless transport belt that sequentially transports the paper to the image forming units of each color;
Reference numeral 104 denotes a driving roller connected to a driving mechanism including a motor and gears to drive the conveyor belt 103; 106e, a motor for driving the driving roller 104; 105, a fixing device for melting and fixing the toner transferred to the paper; is there.

[0004] Data to be printed is sent from the computer to the printer, and image formation according to the printer engine system is completed. When the printer is ready for printing, paper is supplied from a paper cassette and reaches the transport belt 103.
The sheet is sequentially conveyed to the image forming units of each color by the conveying belt 103. The image signals of the respective colors are sent to the respective laser scanners 102 in synchronization with the sheet conveyance by the conveyor belt 103, and the respective photosensitive drums 101a, 101b, 1
An electrostatic latent image is formed on each of the toner images 01c and 101d, the toner is developed by a developing unit (not shown), and is transferred onto a sheet by a transfer unit (not shown). In FIG. 12, image formation is sequentially performed in the order of Y, M, C, and K. Thereafter, the sheet is transported by the conveyor belt 103
The toner image is fixed on the paper by heat in the fixing device 105 and discharged to the outside.

[0005]

However, the above-mentioned prior art has the following disadvantages.

Each photosensitive drum 101a, 101b, 101
c, 101d and the conveyor belt 103 are driven by independent motors 106a, 106b, 106c, 106d, respectively.
If the accelerations of 06b, 106c, and 106d are different, the photosensitive drums 101a, 101b, 101c, and 101d rub against the conveyor belt 103, and the photosensitive drums 101a, 101b, and 1
There is a problem that 01c and 101d are worn and deteriorated.

When a stepping motor is used, the relative rotation speed of a plurality of rotating bodies can be relatively easily minimized. However, since the efficiency of the stepping motor is low, the capacity of the power source is not increased in an apparatus having a plurality of motors. Needs to be increased, resulting in an increase in the size and cost of the apparatus.

Further, in the conventionally used DC brushless motor, since the speed is controlled independently of each other, it is difficult to make the relative rotational speeds of a plurality of rotating bodies coincide during acceleration or deceleration.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art.
Control is performed so that the relative rotation speed of each motor is minimized when each motor is started or decelerated, without causing an increase in the size and cost of the apparatus.
An object of the present invention is to provide a rotator control device and an image forming apparatus capable of suppressing deterioration.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and has the following arrangement.

(1) In a rotating body control device including a plurality of rotating bodies that are in contact with each other and a plurality of motors that respectively drive the plurality of rotating bodies, a relative rotation speed of each motor when each motor is accelerated. Is provided.

(2) In a rotating body control device including a plurality of rotating bodies that are in contact with each other and a plurality of motors that respectively drive the plurality of rotating bodies, a relative rotation speed of each motor when each motor is decelerated. Is provided.

With the above configuration, the relative rotation speed of each motor is controlled to be minimized when each motor is started or decelerated, without increasing the size and cost of the apparatus.
It operates to suppress wear and deterioration of the contact portion of the rotating body.

(3) The plurality of motors are preferably DC motors.

(4) The control means for minimizing the relative rotation speed has a motor rotation speed detection means, a motor speed pattern generation means and a motor operation amount calculation means. And the generated motor speed pattern, and it is preferable to calculate each motor operation amount.

(5) It is preferable that the motor speed pattern generating means comprises numerical value calculating means and parameter storing means, and generates a motor speed pattern by performing a numerical calculation using the stored parameters.

(6) The motor speed pattern generation means comprises motor speed pattern storage means and means for reading a pattern from the storage means, and reads a stored speed pattern at a predetermined timing to generate a speed pattern. It may be.

(7) The drive control of the motor is preferably performed by digital signal processing.

(8) For digital signal processing, a DSP may be used, or a general-purpose microcomputer may be used.

(9) An image forming apparatus using the rotation control device, wherein the plurality of rotating members are a photosensitive drum and a belt in contact with the photosensitive drum.

(10) An image forming apparatus using the rotation control device, wherein the plurality of rotating bodies are a photosensitive drum and a drum in contact with the photosensitive drum.

With this arrangement, it is possible to prevent wear and deterioration of the contact portion between the photosensitive drum and the belt or the drum.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

(Embodiment 1) FIG. 11 shows an image forming apparatus in which a rotation control device according to an embodiment of the present invention is incorporated.

This image forming apparatus, like the conventional color image forming apparatus, has a yellow Y, magenta M, cyan C,
A black K image forming section 1Y, 1M, 1C, 1K is provided. In FIG. 1, reference numeral 1 denotes a photosensitive drum as a rotating body that forms an electrostatic latent image (subscripts a, b, c, and d indicate black K, cyan C, magenta M, and yellow Y, respectively).
6a, 6b, 6c and 6d are photosensitive drums 1a, 1b and 1 respectively.
This is a motor for driving c and 1d. Reference numeral 2 denotes a laser scanner that performs exposure in accordance with an image signal and forms an electrostatic latent image on the photosensitive drum 1 (subscripts a, b, c, and d denote each photosensitive drum 1).
a, 1b, 1c, 1d), 3 is a photosensitive drum 1
, An endless transport belt as a rotating body that sequentially transports the paper to the image forming units of each color, 4 is a drive roller connected to a drive mechanism including a motor and gears and drives the transport belt 3, and 6e is A motor 5 for driving the driving roller 4 is a fixing device for melting and fixing the toner transferred to the sheet.

In the first embodiment, the motor 6a
(Digital signal processor) 20 which constitutes control means for minimizing the relative rotational speed of each of the motors 6a to 6d, 6e when accelerating or decelerating to 6d, 6e.
It has.

When data to be printed is sent from the computer to the printer, and the image formation in accordance with the printer engine system is completed and the printer is ready for printing, paper is supplied from the paper cassette and reaches the transport belt 3, where the transport belt is transported. 3, the paper is sequentially conveyed to the image forming units of each color. The image signal of each color is sent to each laser scanner 2 in synchronism with the sheet conveyance by the conveyor belt 3, and
An electrostatic latent image is formed on each of the photosensitive drums 1a, 1b, 1c, and 1d, the toner is developed by a developing unit (not shown), transferred to a sheet by a transfer unit (not shown), and sequentially arranged in the order of Y, M, C, and K. Image formation is performed sequentially. Then, the paper is transferred to the conveyor belt 3.
The toner image is fixed on the sheet by heat in the fixing unit 5 and is discharged to the outside.

FIG. 2 shows a schematic configuration of a control system of the present apparatus.

Reference numeral 10 denotes a printer as an image forming apparatus. A printer control unit 11 controls each device in the printer. Reference numeral 12 denotes a power supply for supplying power to each device in the printer. Reference numeral 13 denotes sensors for detecting the status of each unit in the printer. Reference numeral 14 denotes a motor control unit that controls motors according to instructions from the printer control unit.

Reference numeral 15 generally indicates motors such as the above-described motors 6a to 6d and 6e, which are power sources of each device in the printer. A display unit 16 notifies the user of the operation status of the printer. A communication controller 17 performs communication between the printer and the host computer. A host computer 18 transfers data to be printed to a printer.

FIGS. 3 and 4 show the configuration of the main part according to the present embodiment.

Reference numeral 1 denotes the photosensitive drum. Reference numeral 40 denotes a DC brushless motor constituting the motor 6 for driving the photosensitive drum 1, which is driven by a gear 46 fixed to a drive shaft of the DC brushless motor 40 and a gear 47 fixed to a rotating shaft of the photosensitive drum 1.

Reference numeral 20 denotes a DSP, which is a DC brushless motor 4
The phase switching control is performed by the rotor position signal from 0, the start and stop of the motor is controlled by the control signal from the printer control unit 11, and the speed control is performed by comparing the speed signal from the printer control unit 11 with the output of the speed detecting means. . That is, the DSP 20 functions as control means for minimizing the relative rotation speed of each motor during acceleration of the DC brushless motor 40, together with the MR sensor 41 constituting the rotation speed detection means for each DC brushless motor 40. The DSP 20 functions as motor speed pattern generation means and motor operation amount calculation means, and compares each motor rotation speed with the generated motor speed pattern during acceleration to calculate each motor operation amount.

FIG. 5 is a block diagram of the DSP 20.

Reference numeral 21 denotes a program controller; 22a, an ALU (arithmetic logic unit) for performing addition / subtraction and logical operation;
b is a MAC for performing a product-sum operation, 23 is a data memory, 24 is a program memory, 25 is a data memory bus, 26 is a program memory bus, 27 is a serial port, 28 is a timer, and 29 is an I / O port. .

As described above, the memory is made independent for the data and the program, the bus is also divided into the data bus and the program bus, and the multiplication and the addition are executed in one machine cycle.
Having C allows high-speed calculations.

One motor can be controlled by one DSP 20, or a plurality of motors can be controlled by one DSP 20.

The DC brushless motor 40 has a U-, V-, and W-phase three-phase star-connected coil 43 and rotor 44.
Further, three Hall elements 42 for detecting the magnetic poles of the rotor 44 are provided as position detecting means of the rotor 44, and the outputs thereof are connected to the DSP 20. Further, a magnetic pattern 45 and an MR sensor 41 constituting the above-described motor rotation speed detecting means are provided on the outer periphery of the rotor 44, and the output thereof is connected to the DSP 20.

Reference numeral 30 denotes a driver for driving the DC brushless motor, which includes three high-side transistors 31 and three low-side transistors 32,
V and W are connected.

The DSP 20 specifies the position of the rotor 44 based on the rotor position signals HU to W generated by the Hall elements.
Generate a phase switching signal. Phase switching signals UU to W,
LU to W control the on / off control of each transistor of the driver, sequentially switch the phase to be excited, and rotate the rotor 44.

Further, the DSP 20 compares the rotation speed target value with the rotation speed information, and generates and outputs a PWM signal. PW
The M signal has a duty of 0 at 0 and a duty of 100 at 255. The PWM signal is logically negated by the phase switching signals UU to W and the NAND gate 33 to perform chopping of the drive current to control the rotation speed of the motor. Note that the DSP 20 may perform all the processing without using the NAND gate.

Reference numeral 34 denotes a current detection resistor which converts a motor drive current into a voltage. The generated voltage is taken into the D / A port of the DSP 20.

The constructions of the driving roller 4 and the motor 6e are the same as those described above, and the description is omitted.

Next, the operation of the motor starting sequence of this circuit will be described with reference to FIG.

When the rotation of the motor is instructed by the printer controller 11 (step 1), the DSP 20 reads the parameter a for calculating the motor speed pattern (step 2).
The counter value t for measuring the elapsed time from the start is set to 1 (step 3). For example, the final target speed of 1000 rpm
m, startup time 500 ms, control frequency 100H
If z, 20 is stored as the parameter a, and
The rotation speed target value v as a motor speed pattern is represented by v =
It is generated by the arithmetic expression of a × t.

Next, the motor is started, and the target rotational speed is calculated by the above equation (step 4). Next, the rotation speed is detected (step 5), and the count value is incremented (step 6).

A motor operation amount is calculated based on the rotation target value and the detected rotation speed (step 7), and a PWM waveform of the motor drive current is output based on the calculated operation amount. PWM
The signal is logically negated by the phase switching signals UU to W and the AND gate 33 to perform chopping of the drive current (step 8).

The above operations (steps 4 to 8) are continued for each motor until the final target speed is reached.
When the target speed is reached, the startup sequence ends (step 9).

In the meaning of executing the above sequence, in the first embodiment, the DSP 20 as the motor speed pattern generating means includes the arithmetic unit 22 having the ALU 22a and the MAC 22b as the numerical calculation means, and the data as the storage means. It has a memory 23 and generates a motor speed pattern by performing a numerical operation using the stored parameters.

For the calculation of the above-mentioned target rotational speed value, another arithmetic expression can be used, or a method of adding the target rotational speed value every time the control routine is executed may be used.

(Embodiment 2) Next, Embodiment 2 of the present invention will be described.

The second embodiment is the same as the first embodiment except that the stored speed pattern is read out at a predetermined timing and a speed pattern is generated.

Since the configuration of the image forming apparatus and the schematic configuration of the control system of the second embodiment are the same as those of the first embodiment, the description is omitted, and the operation of the circuit of the second embodiment will be described with reference to FIG. .

When the motor rotation is instructed from the printer control unit (step 1), the DSP 20 sets the head address of the memory storing the speed pattern as the address of the rotation speed target value to be read (step 2). For example, when the final target speed is 1000 rpm, the time required for startup is 500 ms, and the control frequency is 100 Hz, the acceleration speed pattern is as shown in FIG.

Next, the motor is started, the target rotational speed is read from the set address (step 3), and the rotational speed of the motor is detected (step 4). Repeat (step 5).

A motor operation amount is calculated based on the read rotation speed target value and the detected rotation speed (step 6), and a PWM waveform of the motor drive current is output based on the calculated operation amount. The logical product of the PWM signal is negated by the phase switching signals UU to W and the AND gate 33, and the drive current is chopped (step 7).

The above operations (steps 3 to 7) are continued until the target speed is reached for each motor, and when the target speed is reached, the startup sequence ends (step 8).

In the meaning of executing the above sequence, in the second embodiment, the DSP 20 as the motor speed pattern generating means includes the data memory 23 as the motor speed pattern storing means, and the means for reading the pattern from the data memory 23. The arithmetic unit 22 reads the speed pattern stored at a predetermined timing and generates a speed pattern.

(Third Embodiment) Next, a third embodiment of the present invention will be described.

In the third embodiment, a target rotation speed is generated by calculation, and control is performed when the motor is decelerated.

The operation of this circuit will be described with reference to FIG.

When the motor stop is instructed by the printer control unit (step 1), the DSP 20 reads the parameter a for calculating the motor speed pattern (step 2), and sets the count value t for measuring the elapsed time from the start of deceleration to 1. Set (step 3). For example, the current rotation speed 1000r
pm, final target speed 0 rpm, time required for stopping 500
ms, the control frequency is 100 Hz, 20 is stored as the parameter a, and the motor speed pattern is v = 1.
000-a × t.

Next, the deceleration of the motor is started, and the target rotational speed is calculated by the above-mentioned equation (step 4). Next, the rotation speed is detected (step 5), and the count value t is incremented (step 6).

A motor operation amount is calculated based on the rotation target value and the detected rotation speed (step 7), and a PWM waveform of the motor drive current is output based on the calculated operation amount. PWM
The signal is logically negated by the phase switching signals UU to W and the AND gate 33 to perform chopping of the drive current (step 8).

The above operation is continued until each motor reaches the final target speed, and when the target speed is reached, the sequence ends (step 9).

For the calculation of the rotation speed target value, another arithmetic expression can be used, or a method of subtracting the rotation speed target value every time the control routine is executed may be used.

(Embodiment 4) Next, Embodiment 4 of the present invention will be described.

In the fourth embodiment, a stored speed pattern is read out at a predetermined timing, a speed pattern is generated, and control is performed when the motor is decelerated.

The operation of this circuit will be described with reference to FIGS.

When the motor stop is instructed by the printer control unit 11 (step 1), the DSP 20 sets the head address of the memory storing the speed pattern as the address of the target rotational speed to be read (step 2).
For example, the current rotation speed is 1000 rpm, the final target speed is 0 rpm, the time required for stopping is 500 ms, and the control frequency is 1
The speed pattern for acceleration at 00 Hz is as shown in FIG. 10 and is stored in the memory.

Next, deceleration of the motor is started, the target rotational speed is read from the set address (step 3), the rotational speed of the motor is detected (step 4), and +1 is added to the address. And set again (step 5). A motor operation amount is calculated based on the read target rotation speed and the detected rotation speed (step 6), and a PWM waveform of the motor drive current is output based on the calculated operation amount. The logical product of the PWM signal is negated by the phase switching signals UU to W and the AND gate 33, and the drive current is chopped (step 7).

The above operation is continued for each motor until the target speed is reached, and the sequence ends when the target speed is reached (step 8).

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described.

In the above-described embodiment, a plurality of photosensitive drums and a belt have been exemplified as the plurality of rotating bodies. However, similar effects can be obtained by using a drum instead of the belt.

[0075]

As described above, according to the present invention,
Control the motor so that the relative rotation speed of each motor is minimized when starting (accelerating) or decelerating each motor, without increasing the size and cost of the device, and reducing the wear and deterioration of the rotating body such as the photosensitive drum. Operate to suppress.

[Brief description of the drawings]

FIG. 1 is an operation explanatory diagram of an image forming apparatus according to Embodiment 1 of the present invention;

FIG. 2 is a schematic configuration explanatory diagram of a control system according to the first embodiment.

FIG. 3 is an explanatory diagram of a configuration of a main part of the first embodiment.

FIG. 4 is an explanatory diagram of a configuration of a main part of the first embodiment.

FIG. 5 is an explanatory diagram of a configuration of a main part of the first embodiment.

FIG. 6 is an operation explanatory diagram of the image forming apparatus according to the second embodiment.

FIG. 7 is an operation explanatory diagram of the second embodiment.

FIG. 8 is an operation explanatory diagram of the third embodiment.

FIG. 9 is an operation explanatory diagram of the fourth embodiment.

FIG. 10 is an operation explanatory diagram of the fourth embodiment.

FIG. 11 is an overall explanatory diagram of the image forming apparatus according to the first embodiment.

FIG. 12 is an overall explanatory diagram of a conventional image forming apparatus.

[Description of Signs] 1a, 1b, 1c, 1d {photosensitive drum (rotating body) 2} laser scanner 3} transport belt (rotating body) 4} drive roller (rotating body) 5} fixing device 6a , 6b, 6c, 6d {motor 10} printer 11 {printer control unit 12} power supply 13} sensors 14} motor control unit (control means) 15} motors 16} display unit 17} {Communication controller 18} Host computer 20 {DSP (control means) 21} Program controller 22 {Arithmetic unit (arithmetic means, reading means) 22a {ALU 22b} MAC 23} Data memory (storage means) 24 program memory 25 data memory bus 26 program memory bus 27 serial port 28 timer 29 I / O port Port 30 driver 31 high-side transistor 32 low-side transistor 33 NAND gate 34 current detection resistor 35 current limiter 36 comparator 40 DC brushless motor 41 MR sensor ( Motor speed detecting means 42 42 Hall element 43 Coil 44 Rotor 45 Magnetic pattern 46 Motor shaft gear 47 Photosensitive drum rotary shaft gear

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Claims (10)

[Claims] 1. A rotating body control device comprising: a plurality of rotating bodies that are in contact with each other; and a plurality of motors that respectively drive the plurality of rotating bodies, wherein a relative rotation speed of each motor during acceleration of each motor is determined. A rotating body control device comprising control means for minimizing. 2. A rotating body control device comprising: a plurality of rotating bodies abutting on each other; and a plurality of motors for driving the plurality of rotating bodies, wherein a relative rotation speed of each motor at the time of deceleration of each motor is determined. A rotating body control device comprising control means for minimizing. 3. The rotating body control device according to claim 1, wherein the plurality of motors are DC motors. 4. The control means for minimizing the relative rotation speed has a motor rotation speed detection means, a motor speed pattern generation means and a motor operation amount calculation means, and controls each motor rotation speed during acceleration or deceleration. The rotating body control device according to any one of claims 1 to 3, wherein the motor operation amount is calculated by comparing the generated motor speed pattern with each other. 5. The motor speed pattern generating means according to claim 1, wherein said motor speed pattern generating means comprises a numerical value calculating means and a parameter storing means, and generates a motor speed pattern by performing a numerical value calculation using the stored parameters. 5. The rotating body control device according to 4. 6. The motor speed pattern generation means comprises motor speed pattern storage means and means for reading a pattern from the storage means, and reads out the stored speed pattern at a predetermined timing to generate a speed pattern. The rotating body control device according to claim 1, wherein: 7. The rotating body control device according to claim 1, wherein drive control of the motor is performed by digital signal processing. 8. The rotation control device according to claim 7, wherein a DSP or a microcomputer is used for the digital signal processing. 9. An image forming apparatus using the rotation control device according to claim 1, wherein the plurality of rotating bodies are a photosensitive drum and a belt in contact with the photosensitive drum. An image forming apparatus comprising: 10. An image forming apparatus using the rotation control device according to claim 1, wherein the plurality of rotating bodies are a photosensitive drum and a drum in contact with the photosensitive drum. An image forming apparatus comprising: