JPH01225973A - Controller for speed of revolution of motor - Google Patents

Abstract

PURPOSE:To remove selection with respect to the turn off characteristics of a transistor and to prevent cost from being increased by increasing/decreasing the raising duty ratio of a motor with the aid of setting input from an outside, so that the individual difference of the transistor is removed. CONSTITUTION:When a simulation mode is set by turning on a dip switch SW 1, the value of the raising duty ratio D stored in the memory area MA 1 of a RAM 13 is changed to an inputted value by the key operation of a console panel 9. In this manner, after finishing the assembling operation of a copying machine main body 21 or at the time of maintenance, the simulation mode is carried out, and a voltage duty ratio impressed to a driving circuit is changed by the key operation in such a manner that the pulse of the driving voltage impressed to the motor M1 becomes a prescribed duty ratio. Thus, a work to select the characteristic of electric parts such as the transistor, etc., constituting the driving circuit is omitted; so that the increase of the cost is prevented and also a stabilized producing state is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention relates to a motor rotation speed control device that performs feedback control on the duty ratio of drive pulses input to a servo motor, such as an optical system drive device in a copying machine. .

(b) Conventional technology For devices that require constant speed rotation, such as the drive motor for the optical system of a copying machine, feed control is performed.
The drive voltage applied to the motor is increased or decreased so that the motor rotation speed matches the target value.

As a result, as shown in FIG. 5, the rotational speed of the drive motor of the optical system device maintains the target value ■1 during forward movement, for example, from point B, the leading edge position of the document image to point E, the trailing edge position of the document image, as shown in FIG. The optical system moves under the document table at a predetermined scanning speed. In this feedback control, it is necessary to quickly bring the rotational speed of the motor close to the target value V in the rising state after the motor starts rotating until the target value 1 is reached. Therefore, in the drive circuit for the motor M1 shown in FIG. 6, the on/off duty ratio of the transistor Tr is set to a predetermined rising duty ratio by the 5CPU 61, so that the rotational speed of the motor can quickly match the target value.

(C) Problems to be Solved by the Invention However, in the conventional motor rotation speed control device, the motor is driven at a duty ratio set in the control section due to individual differences in the track resistor that constitutes a part of the motor drive circuit. There were times when I couldn't do it. In particular, the individual differences in the turn-off time of transistors are relatively large, and in the drive circuit shown in FIG. 6, the output voltage vO of the transistor Tr is
is in the state shown in FIG. 7, and the duty ratio of the voltage Vo applied from the transistor Tr to the motor M1 is set by the 5CPU 61 of the control unit according to the difference between the delay time T at turn-on and the delay time T at turn-off. The duty ratio becomes larger by (Ts-t+)/Ts, and the average voltage per unit time of the voltage 0 also increases. Therefore, in the start-up state of the rotation of motor M1, 1 in FIG.
As shown by the dashed dotted line, there was a problem in that overshoot and undershoot were significant, and it took a long time for the rotation of the motor M1 to converge to the target value ■1. One way to improve this is to select and use transistors with short turn-off times in the drive circuit, but this may lead to an increase in cost depending on the yield status of the transistors, and due to individual differences between transistors. There was a problem that production stability deteriorated.

The purpose of this invention is to enable the start-up duty ratio of the motor to be increased or decreased by external setting input, thereby absorbing individual differences between transistors, eliminating selection related to transistor turn-off characteristics, and preventing cost increases. At the same time, it is an object of the present invention to provide a motor rotation speed control device that can maintain good production stability.

(d) Means for Solving the Problems The motor rotation speed control device of the present invention controls the motor drive pulses at a preset rising duty ratio until the motor rotation speed reaches the target rotation speed after the start of driving. A motor rotation speed control device that performs duty control according to the present invention is characterized in that a rising duty ratio changing means is provided for increasing or decreasing a set value of the rising duty ratio in a specific operation mode.

('e) Effect In the present invention, in a specific operation mode, the duty ratio of the drive pulse in the rising state of the motor can be increased or decreased by the rising duty ratio changing means. Therefore, by executing a specific operation mode after completing a product, and changing the startup duty ratio while checking the startup state of motor rotation,
The desired start-up condition is achieved.

(flExample) Examples of the present invention will be explained below by taking a copying machine as an example. Fig. 2 is a schematic front cross-sectional view of a copying machine equipped with a motor rotation speed control device which is an embodiment of the present invention. be.

A document table 22 made of hard transparent glass is provided on the top surface of the copying machine main body 21. An optical system device 31 is provided below this document table 22 . This optical system device 3
1 consists of a light source 32, mirrors 33 to 36, and a lens 37. Of these, the light source 32 and the mirrors 33 to 35 move back and forth on the lower surface of the document table 22 in the directions of arrows A and B during the copying process, and scan the image of the document placed on the document table 22. The light from the light source 32 reflected from the original is distributed as shown by the dashed line in the figure, and is guided to the surface of the photoreceptor drum 23 via mirrors 33 to 36 and a lens 37.

As a result, an electrostatic latent image is formed on the surface of the photoreceptor drum 230.

FIG. 3 is a perspective view showing the main parts of the optical system device of the copying machine.

The light source 32 is fixed to a base 38 together with a mirror 33 (not shown). Further, mirrors 34 and 35 are fixed to the base 39. These bases 38 and 39 are connected to the guide 4
0 and 41. Furthermore base 3
The rotation of the motor Ml is transmitted to the motors 8 and 39 via a wire 42 as a driving force for linear motion. At this time, the base 38 moves in the directions of arrows A and B at twice the speed of the base 39 due to the action of a pulley (not shown). Further, the sensor C1 detects the base 38 during its return movement and specifies the position of the optical system device.

FIG. 1 is a block diagram showing the main parts of the control section of the copying machine.

A control unit that controls each part of the copying machine main body 21 is constituted by a mask slave CPU system. The main control unit 1 is composed of a master CPU (M-CPU) 2 and a ROM 3 and a RAM 4 connected thereto. This M-CPU 2 includes a slave CPU (S-
CPU) 6.11 etc. are connected. The operation panel control section 5 includes a 5-CPU 6 and a ROM connected thereto.
7 and RAM 8, the copying machine main body 2
1 is controlled by an operation panel 9 provided on the top surface of the device. The motor control unit IO is constituted by a 5-CPUI 1 and a ROM 12 and a RAM 13 connected thereto, and controls the rotation of a motor M1 that provides driving force to the optical system device.

Specifically, the rotational speed of the motor M1 is read by the rotary encoder 14, and the duty ratio of the drive pulse is set so that the force corresponds to a predetermined target value. RAM13 memory area M A
1 stores a rising duty ratio during forward movement of the motor Ml, and this RAM 13 is backed up by a battery (not shown). In addition, the copying machine main body 21
When a dip switch SW1 provided in a part of the camera is turned on, the simulation mode is set.

FIG. 4 is a flowchart showing the processing procedure of the motor control unit that constitutes a part of the control unit of the copying machine.

When the power is turned on, the 5-cpull forming a part of the motor control unit 10 checks whether it is in the normal operation mode (nl). When dip switch SWL is operated at the end of assembly work or during maintenance, M
-A signal related to the simulation mode setting is output from the CPU 2 to each of the 5-CPUs. Therefore, in nl, it is determined whether the communication mode is set or not. At this time, if the dip switch SW1 is not turned on and the mode is normal operation mode, the M-CP
Waiting for reception of optical system feed signal from U 2 (
n2).

After a predetermined period of time has passed after the print switch on the operation panel 9 is operated, an optical system feed signal is sent from the M-CPU 2 to prompt the optical system to start scanning. When the optical system feed signal is sent out, the motor M is activated at the forward movement rising duty ratio DI stored in the memory area MAI of RAM8.
1 (n3). This rising duty ratio D1
The driving is continued for 'a' until the detected value Va of the rotary encoder 14 matches the target value (1) (n4).

When the detection value Va of the rotary encoder 14 reaches the target value V, the drive voltage of the motor M1 is feedback-controlled by pIDIl]l etc. based on the detection value of the rotary encoder 14 until a feed stop signal is sent out (n
5. n6).

When the optical system device 31 reaches the rear end of the document placed on the document table 22 and a feed stop signal is sent, it waits for the sending of an optical system return signal (n?). When the optical system return signal is sent out, the detected value Va of the low reencoder 14
drives the motor M1 at the rising duty ratio D2 during the backward motion (n8, n9). When the detection value Va of the rotary encoder 14 matches the target value 3 for the backward movement shown in FIG. Feedback control of the drive voltage of M1 (nlo,
n1l). When the optical system device 31 reaches the sensor C8, the duty ratio is reduced to two steps and the motor is stopped (n12
).

When the depth inch SW1 is turned on and the simulation mode is set, the memory area M A of the RAM 13
The value of the rising duty ratio D+ stored in 1 is changed to the value input by key operation on the operation panel 9 (n13, n14). In the simulation mode, the operator uses an oscilloscope or the like to measure the drive voltage (2) of the motor M1 in the motor drive circuit shown in FIG. Check the pulse waveform of , and change and input the rising duty ratio so that the duty ratio matches a predetermined value. At this time, the input method is to enter numerical values using the numeric keypad, or to
Possible inputs include increase/decrease input using the down key. In the above processing, nl, n13. nl4 corresponds to the rising duty ratio changing means of the present invention.

As described above, according to this embodiment, the copying machine main body 21
After completing the assembly work or during maintenance, run the simulation mode, extract the drive voltage pulses applied to the motor M1, and adjust the voltage applied to the drive circuit by key operation so that the drive pulses have a predetermined duty ratio. Duty ratio can be changed. As a result, it is possible to correct errors in the duty ratio caused by individual differences in the electrical components constituting the drive circuit, and apply a drive voltage with an appropriate duty ratio to the motor M1.

(g) Effects of the Invention According to the present invention, the rising duty ratio of the motor drive pulse can be increased or decreased during a specific operation mode. Therefore, it is necessary to correct the error in the duty ratio that occurs in the drive circuit due to individual differences in the electrical components that make up the motor drive circuit, and to set the start-up duty ratio so that the motor rotation speed achieves the desired start-up state. Can be done. This makes it possible to omit the work of selecting the characteristics of electrical components such as transistors that constitute the drive circuit, thereby preventing an increase in costs and maintaining a stable production state.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram of the main parts of the control section of a copying machine equipped with a motor rotation speed control device according to an embodiment of the present invention, and Fig. 2 is a schematic front cross-sectional diagram of the copying machine. , the third figure is a perspective view of the main part of the optical system device included in the copying machine, and FIG. 4 is a flowchart showing the processing procedure of the motor control unit forming a part of the control unit of the copying machine. FIG. 5 is a diagram showing changes in the rotational speed of an optical system drive motor in a general copying machine including an embodiment of the present invention, and FIG. 6 is a circuit diagram showing a general motor drive circuit. FIG. 7 is a diagram showing the relationship between the duty ratio of the voltage applied to the motor drive transistor and the duty ratio of its output in a conventional motor drive circuit. Further, FIG. 8 is a diagram showing a rising cloudy state due to an error in the duty ratio occurring in the same drive circuit. Ml-motor, 5w1-dip switch.

Claims (1)

[Claims] (1) In a motor rotation speed control device that duty-controls the motor drive pulse at a preset rising duty ratio until the motor rotation speed reaches the target rotation speed after the start of driving, the A motor rotation speed control device comprising a rising duty ratio changing means for increasing/decreasing a set value of the rising duty ratio.