JPH01222681A - System for driving and controlling setting-head of printer - Google Patents

Abstract

PURPOSE:To reduce the jitter of speed change on acceleration and deceleration, by driving a one-reciprocating setting head with a PWM controlling waveform at the time of making a power source, and by detecting the exciting duty of the then motor, to use it as a set value at the time of controlling the following constant-frequency chopper. CONSTITUTION:When a power source is made, then the output of a PWM chopper controlling circuit 4 is fed to a motor 12, and a setting head 1 is driven by one reciprocation. By an exciting duty detection circuit 6, the maximum value and the minimum value of the duty of the exciting current of the then motor 12 are detected, and are fed to exciting duty setting memory 7. When one reciprocation is performed by the setting head 1, then the output of a constant-frequency chopper controlling circuit 5 is fed to the motor 12. In this case, based on the maximum value at the time of acceleration, and based on the minimum value at the time of deceleration, the frequency of the constant- frequency chopper controlling circuit 5 is set.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for controlling the drive of a printer's print head, the present invention enables speed control that can respond to minute speed fluctuations and can also respond to large changes in mechanical load and power supply voltage. The present invention is intended to provide a PWM chopper control means, a constant frequency chopper control means, an excitation duty detection means, and an excitation duty setting circuit having a programmable timer module for controlling the constant frequency chopper control means and a memory for setting the excitation duty. A printer print head drive control method,
The PWM chopper control means operates the print head, the excitation duty detection means detects the maximum and minimum values of the excitation duty when the print head is in the printing area, stores the detected values in the excitation setting memory, and then teeth,
According to the stored value, the excitation duty of the constant frequency chopper control circuit is set based on a maximum value during acceleration and a minimum value during deceleration, so that constant frequency chopper control is performed before regular printing.

(Industrial Application Field) The present invention relates to a printer print head drive control method for controlling the drive of a printer's print head, and in particular to a PWM (
(Pulse Width Modulation) A control method that drives the print head one reciprocating time when the power is turned on using a control waveform, detects and stores the motor excitation duty at that time, and uses it as a set value for subsequent constant frequency chopper control. It is.

[Prior Art] As a method of driving the print head of a printer, there is a method as shown in FIG. 2 in which a screw gear 23 is used and the screw gear 23 is rotated by a motor 12 to move the print head 21 horizontally. Since the print head must always move at a constant speed during printing, the configuration is such that the rotation speed of the screw gear is detected and feedback is applied to the rotation of the motor.

This configuration is shown in FIG. That is, the comparator 2 compares the signal from the rotation speed detection sensor that constitutes the speed detection section 1 with the reference speed from the reference speed setting device 3, and if the rotation speed of the screw gear is faster than the reference, it is "H", and if it is slower than the reference, it is "H". Outputs a "L" signal. The motor controller 30 uses this signal to excite the motor 12 to accelerate the motor 12 if the signal is slow, or to decelerate the motor 12 if the signal is fast.
There are two types of control: PWM (pulse width modulation) chopper control and constant frequency chopper control. In the former, if the speed is faster than the standard, the duty (duty factor) of the motor's excitation current is gradually decreased, and conversely, if the speed is slower than the standard, the duty of the excitation current is gradually increased, and the duty varies widely from 0 to 100%. Therefore, it can handle a wide range of loads on the motor.

In the latter case, the magnet is excited with a predetermined duty when it is faster than the reference and when it is slower than the reference. The above-mentioned comparator output is shown in the upper part of FIG. 4, the control current waveform in PWM chopper control is shown in the middle part, and the control current waveform in constant frequency chopper control is shown in the lower part of FIG.

[Problem to be solved by the invention]

As mentioned above, when the PWM chopper control method is used, there is a problem that it takes time to reach a constant speed when starting the print head, etc., and when the constant frequency chopper control method is used, the duty changes suddenly depending on the speed. It is also possible to make the motor speed more responsive to load fluctuations, but if the amount of change in the excitation current duty during acceleration/deceleration is increased, the speed fluctuations of the motor will become larger, and conversely, the amount of change will be If it is made too small, it will not be possible to deal with variations in the load on the helical gear, and the specified speed may not be reached even if constant acceleration or deceleration excitation is performed.

An object of the present invention is to enable speed control that minimizes speed fluctuations and can respond to large changes in mechanical load and power supply voltage.

[Means to solve the problem]

As illustrated in FIG. 1, the print head drive control system of the printer of the present invention includes a central processing unit (CPU) 8, a motor 12 for driving the print head, and a speed detection means 1 for detecting the moving speed of the print head. , a comparison means 2 that compares the reference speed set by the CPU 8 and the signal from the speed detection means 1, a PWM chopper control means 4 that controls the motor 12 to maintain the reference speed in response to the output of the comparison means 2, and a constant Frequency control means 5, excitation duty detection means 6
, and an excitation duty setting circuit 7B having a programmable timer module 7A for controlling the constant frequency chopper control means 5 and an excitation duty setting memory 7.

Then, the print head is operated by the PWM chopper control means 4, and the maximum and minimum values of the excitation duty of the motor when the print head is in the printing area are detected by the excitation duty detection means 6, and the detected values are set as the excitation duty. CP memory 7 for subsequent printing.
Based on the command from U8 and the value in the excitation duty setting memory 7, the excitation duty of the constant frequency chopper control means 5 is set based on the stored maximum value during acceleration and the minimum value during deceleration, thereby performing constant frequency chopper control. The means is configured to perform control before regular printing.

[Operation] According to this method, PWM chopper control detects and sets the excitation current duty values during acceleration and deceleration in constant frequency chopper control that takes into account the current state of the mechanical parts and power supply voltage. This makes it possible to suppress jitter in speed changes during acceleration and deceleration.

(Embodiment) FIG. 1 shows a block circuit diagram of an apparatus for performing a print head drive control system for a printer as an embodiment of the present invention.

This device includes a speed detection section 1, a comparison section 2, a reference speed setter 3,
PWM chopper control circuit 4, constant frequency chopper control circuit 5
, an excitation duty detection circuit 6, an excitation duty setting circuit 7B, CP[IB, AND gates 9 and 10, an OR gate 11, and a motor 12. The excitation duty setting circuit 7B includes a PTM (programmable timer module) 7A and an excitation duty setting memory 7. The speed detection section 1 includes a rotation speed detection sensor 24 (FIG. 2), and is driven via a print head carrier 25 on which a print head 21 is mounted. The output of the speed detection section l is supplied to one input of the comparison section 2. The other input of the comparator 2 is supplied with a reference speed signal from a reference speed setter 3. The comparator 2 compares these two inputs, outputs a signal for determining whether the detected speed is faster than the reference speed, and supplies the signal to the PWM chopper control circuit 4 and constant frequency chopper control circuit 5.

When this device is powered on, the print head operates only one round trip. During this time, the AND gate 9 is controlled by the CPU s, and the output of the PWM chopper control circuit 4 is connected to the motor 12 via the OR gate 11. When the above-mentioned one round trip of the print head is completed, the AND gate IO is
The output of the constant frequency chopper control circuit 5 is connected to the motor 12 via the OR gate 11. The excitation duty detection circuit 6 detects the maximum and minimum values of the duty of the excitation current of the motor 12 when the drive of the print head is controlled by the PWM chopper control circuit 4.

This detected value is supplied to the excitation duty setting memory 7 and stored therein.

Printing on the medium is performed using constant frequency chopper control. A constant frequency pulse serving as a reference for this control can be arbitrarily created using CPII 8 using PTM.

At startup, increase the excitation duty during acceleration (for example, 1
00% Inu Kikushi), so that it can be accelerated in a short time. After the speed is accelerated to the reference speed, the excitation duty during acceleration and deceleration is set to a value for printing speed, and control is performed. The excitation duty for this printing speed is a value increased by 10% from the maximum value obtained during the above-mentioned PWM chopper control period for acceleration, and a value increased by 10% from the minimum value obtained in the same manner for deceleration.
A value of 0% reduction is used to allow for an allowance for the thickness of the print medium. When stopping, the excitation duty for stopping is reset and the print head carrier is stopped.

The operating range of the print head will be explained using FIG. 5. The range in which printing is performed on the print medium by the print head is the print area, and both ends outside of this area are the start area and the stop area. Duty detection when controlled by the PWM chopper control circuit in the excitation duty detection circuit 6 described above relates to values in the print area.

Next, the processing steps in the apparatus of the embodiment will be explained using FIG. 6 and the seventh section. FIG. 7 shows the initial operation of the process shown in FIG. 6 in detail.

First, in step S61, the power is turned on. Next, an initial operation in step S62 is performed. This initial operation is shown in FIG. When the initial operation is completed,
Proceed to step S63. Step S63 sets the excitation duty for startup. From here, we enter the startup control part in constant frequency chopper control.

In this process, the excitation duty is set to 10, for example, as described above.
Set 0% larger. In step S64, the motor is excited with the set excitation duty. In step S65, the vehicle waits until the speed increases to the reference speed. This is the startup control part.

Next, printing speed control is started, and in step S66, the excitation duty is set for the printing speed. In step S67, the process waits until the printing area is finished. Upon completion of step S67, the process stops at step 368. If the next line is to be printed, the process returns to step S63 and this process is repeated. If printing is completed, the process advances to step S69, where the power is cut off and the process ends.

The initial operation will be explained using FIG. 7. First, in step S71, PWM chopper control is selected. Process S
The process advances to step 72, where the motor is excited.

Wait until the reference speed is reached in step S73. In step S74, the maximum duty is set to 0% and the maximum duty is set to 100%. In step S75, it is determined whether the excitation duty of the motor is smaller than the minimum duty in step S74. If it is smaller, the minimum duty is updated to the excitation duty.

Then, the process advances to the next step S77.

If the excitation duty is greater than or equal to the minimum duty, step S7
6 and proceed to step S77. In step S77, if the excitation duty is greater than the maximum duty, step S78
If the result is below, the process advances to step S79.

Step 378 updates the maximum duty to the excitation duty. After step S78, the process advances to step S79. In step S79, if the printing area is not completed, the process returns to step S75.
Repeat these steps, and when the printing area is completed, step S
Proceed to 80 and stop. In step S81, the print head is returned to the starting point, and in the next step S82, constant frequency chopper control is selected to complete the initial operation, and the process proceeds to step S63 in FIG.

According to the above-mentioned device, considering the load on the mechanical part and changes in the power supply voltage, the conditions under which the output torque of the motor is maximum with respect to the load applied to the motor, that is, the load on the mechanical part is small (power supply voltage The duty on the deceleration side must be made small so that the specified speed can be reached even under conditions where the The duty on the acceleration side must be increased so that the specified speed is reached even when the speed is reached, and this increases the difference in the duty during acceleration and deceleration, which compensates for the disadvantage that the jitter in the speed change during acceleration and deceleration becomes large. can be done, i.e.
By moving the print head to change the excitation duty using PWM chopper control and detecting the excitation duty at this time, there is no need to consider variations in mechanical parts or power supply voltage, and excitation under individual mechanisms and voltages can be adjusted. Duty can be set.

〔Effect of the invention〕

According to the present invention, it is possible to perform speed control that can minimize speed fluctuations and can respond to large changes in mechanical load and power supply voltage.

[Brief explanation of the drawing]

Fig. 1 is a block circuit diagram of a device that performs a print head drive control method for a printer as an embodiment of the present invention, Fig. 2 is a diagram showing the configuration of the printer, and Fig. 3 is a block diagram of a motor speed control circuit. , Fig. 4 is a diagram showing the control waveform of the motor, Fig. 5 is a diagram explaining the operation of the print head, and Fig. 6 is a diagram showing the control waveform of the motor.
FIG. 7 is a flowchart of the processing steps of the initial operation of FIG. 6. In the figure, 1...Speed detection unit, 2...Comparison unit, 3...Reference speed setter, 4...Quadruple chopper control circuit, 5...Constant frequency chopper control circuit, 6... - Excitation duty detection circuit, 7... Memory for excitation duty setting, 7A... Programmable timer module, 7B... Excitation duty setting circuit, 8... CPU. 9.10...AND gate, 11...OR gate, 12...motor.

Claims (1)

[Claims] A central processing unit (8) and a motor (
12), speed detection means (1) for detecting the moving speed of the print head, and comparison means for comparing the signal from the speed detection means (1) with a reference speed set by the central processing unit (8). (2), pulse width modulation chopper control means (4) and constant frequency chopper control means (5) which receive the output of the comparison means (2) and control the motor to maintain the reference speed.
), an excitation duty setting circuit (7B) having an excitation duty detection means (6), a programmable timer module (7A) for controlling the constant frequency chopper control means, and an excitation duty setting memory (7). , The print head is operated by the pulse width modulation chopper control means (4), and the maximum and minimum values of the excitation duty of the motor (12) when the print head is in the print area are detected by the excitation duty detection means (6). the detected value is stored in the excitation duty setting memory (7), and the constant frequency chopper control means ( 5) The excitation duty is set based on the stored maximum value during acceleration and based on the stored minimum value during deceleration, and the motor (12) is driven by the constant frequency chopper control means before the regular printing operation. Print head drive control method of the printer to be controlled.