JPH06206354A - Serial printer - Google Patents

Abstract

PURPOSE:To achieve the simplification and enhancement of accuracy of the processing due to a backlash (BR) correcting CPU by confirming BR quantity as time quantity. CONSTITUTION:At first, an HP is confirmed before the start of printing and a carriage is received at the printing standby position on the left side of the HP. Next, the carriage is moved in a right (forward) direction to confirm an HP trigger. A CPU counts the time (CR lag) from the confirmation time of the HP trigger to the point of time when a stepping motor control pulse (HP pulse) is generated immediately after the confirmation time using a timer. Next, the carriage is moved to a predetermined position to reverse a CR motor to be moved in a left (return) direction to enter the HP sensor in the reverse direction. The CPU counts the time from the time when the pulse corresponding to the HP pulse is generated to the time when the HP trigger is again actually generated using a timer. This time is set to an HP lag 0. Since HP lag = HP lag 0-CR lag is calculated, the carriage may be timewise delayed by the quantity corresponding to the HP lag.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer, and more particularly, it uses a stepping motor or other motor having a relatively large controllable unit to facilitate positional deviation correction (backlash correction) on the forward and return paths of a carriage. Related to serial printers.

[0002]

2. Description of the Related Art As a known document describing the prior art of the present invention, there is, for example, Japanese Patent Publication No. 62-39110, entitled "Printing Position Control Method for Printer". This publication manages the printing position for printing in each direction based on the number of drive pulses of a motor for moving the carriage back and forth or the actual amount of rotation. Prior to starting the printing operation, a sensor provided By moving the carriage back and forth across the position, the shift amount at the time of direction change is detected and stored, and at the time of printing operation, printing is performed with the motor operation amount corrected by the shift amount corresponding to the printing direction. It controls the position.

However, in the conventional method in which the correction is performed by the actual movement amount as described above, it is impossible to achieve an accuracy higher than the minimum control unit of the carriage motor. Further, in recent years, with the downsizing of printers, small and inexpensive stepping motors have been used as carriage motors, and the displacement amount in one step has increased. Since several dots are printed per motor control pulse, there is a problem in that BR (backlash) correction based on the number of pulses is too inaccurate.

[0004]

The present invention has been made in view of the above circumstances, and by considering the moving speed of a carriage as a substantially constant speed, the backlash amount is recognized as a time amount instead of a motor pulse number, and The purpose of the present invention is to provide a serial printer that simplifies and improves the accuracy of processing in the central processing unit for rush correction.

[0005]

In order to achieve the above object, the present invention provides (1)
When the carriage equipped with the print head is in operation, a sensor means for detecting a signal indicating that the carriage has passed a home position, which is a predetermined position, and the carriage is reciprocally driven based on the sensor output from the sensor means. The carriage motor that electrically recognizes the position deviation amount of the forward path and the return path of the carriage based on the sensor output from the sensor means, and the recognized position deviation amount in order to prevent the print deviation at the time of reciprocal printing. On the basis of the correction means for correcting the print timing of the forward path and the backward path, and the mechanical passing signal generation by the sensor means in the one carriage driving direction is set as the mechanical home position,
When the generation timing of the mechanical home position that is electrically predicted in the other carriage drive direction is the electrical home position, the time difference between the electrical home position and the actual mechanical home position is calculated as described above. And a conversion means for converting the passing signal into a digital signal, a central processing means for performing motor control / print timing control, and the central processing means. Recognizing means for recognizing the temporal difference by the timer function of the processing means, means for taking the digital passing signal into the interrupt terminal of the central processing means, and control of the timer function for recognizing the temporal difference are set to the interrupt. Providing a processing means for performing the interrupt routine of the corresponding software, further, (3)
In the above (2), a sensor means for outputting the digital passing signal as a falling / rising signal in which 0/1 of the digital signal changes before and after its generation, an output converting means of the sensor means, and a rising edge as a trigger. Central processing means having an interrupt terminal for triggering a falling edge, means for taking a digital passing signal into the two interrupt terminals, and 2
A control means for controlling the timer function for recognizing the time difference corresponding to each of the two software interrupt routines by one interrupt is provided, and further, (4) above (2) or (3) In the above, a correction means is provided for preliminarily holding the time required for software processing from the interrupt input to the timer function control by the interrupt routine as data, and correcting the value of the temporal difference. In 1), (2), (3), or (4), an appropriate range is set in advance for the temporal difference and the positional deviation correction value due to the temporal difference, and when it goes out of the range, a warning is issued, the device is stopped, etc. It is characterized in that a driving means for carrying out is provided. Hereinafter, description will be given based on examples of the present invention.

FIG. 1 is a block diagram for explaining an embodiment of a serial printer according to the present invention. In the figure, 1 is a recording sheet, 2 is a platen roller, 3 is a print head, 4 is a carriage, and 5 is an HP. (Home position) sensor (actuator), 6 is an HP (home position) sensor (fat sensor), 7 is a carriage drive belt, 8 is a CR (carriage) motor (stepping motor), and 9 is a pulley. The carriage 4 is moved left and right by a stepping motor 8 and a carriage drive belt 7. The print head 3 is fixed on the carriage 4 and prints on the recording paper 1 wound around the platen roller 2. An HP sensor (strip) 5 is attached to the carriage 4, and at a print operation waiting position, a photo sensor 6 including a light emitting element and a light receiving element, which is installed so as to sandwich the HP sensor 5, is provided. . The output of the photo sensor 6 is HP
It changes depending on whether or not the sensor 5 is shielded from light, and a digital signal of "1" or "0" can be obtained by discriminating with an appropriate threshold value.

Before the start of printing, the stepping motor 8
Start, move the carriage 4 to the left, and
A preparatory operation (initialization operation) is performed to stop at the print operation waiting position (home position) based on the signal that is inverted. Next, in the printing operation, the stepping motor 8 is started, the carriage 4 at the home position is moved to the right, and the number of drive pulses of the stepping motor 8 is counted by the counter from the time when the output signal of the photo sensor 6 is reversed. Printing is performed at a predetermined position based on the number. When it finishes printing the number of print characters on one line, it slows down and stops. As described above, the right direction printing for moving the carriage 4 from left to right and printing is completed. Next, in the leftward printing opposite to the above, the carriage 4 is moved leftward from the position where the carriage 4 is stopped on the right side,
The content of the counter is decremented by the drive pulse of the stepping motor 8 as it moves, and printing is started when a predetermined count value is reached, and stopped at the home position when printing is completed.

2 and 3 are a block diagram and a time chart of a serial printer according to the present invention.
Is a central processing unit (CPU), 11 is a digital edge signal generator, 12 is a print controller, 13 is a motor controller,
In addition, the same reference numerals are attached to the portions having the same operations as those in FIG. The horizontal axis of the time chart of the electric signal in FIG. 3 indicates time instead of distance. The operation of the serial printer according to the present invention will be described below with reference to FIGS.

Before starting printing, the serial printer first checks the HP and stores the carriage at the print standby position on the left side of the HP. After that, the carriage is moved to the right (outward path) to recognize the passing time (HP trigger). C
PU is the time (C) from the HP trigger recognition time to the generation of the stepping motor control pulse (HP pulse) immediately after that.
R lag) is counted by a timer. After that, the carriage is moved to a predetermined position, the CR motor is rotated in the reverse direction, is moved to the left (return path), and enters the HP sensor from the opposite direction.
At this time, the CPU counts the time from the time when the pulse corresponding to the HP pulse is generated until the HP trigger is actually generated again. This time is referred to as HP lag 0.

In the present invention, since the distance and the time are considered to be equivalent by considering the carriage speed to be constant,
As a matter of course, while the BR correction data such as the timer count is being collected, it is desirable that the acceleration / deceleration of the CR motor has already been completed and the speed is within the current speed range. At this time, the following relationship holds, and thus the HP lag is calculated. HP lag = HP lag 0-CR lag In the BR correction of the actual printing, if the generation of the print start signal on the return path is delayed by the amount of HP lag with respect to the timing of the generation of the print start signal on the outward path. Good. By the above operation, BR correction with the timer accuracy of the CPU becomes possible.

First, claim 1 will be described. It has the following functions (1) to (5) and backlash (BR)
It is a serial printer capable of reciprocal printing that recognizes quantity as time. (1); The sensor means (HP sensor) detects a signal indicating that the carriage has passed a predetermined position (home position: HP) during the operation of the carriage on which the print head is mounted. The passing signal is called an HP trigger. (2); the carriage motor (CD motor) is the HP
The carriage is reciprocally driven based on the output of the sensor. (3); The BR amount recognition means electrically recognizes the amount of positional deviation (backlash: BR) between the forward and backward passes of the carriage based on the output of the HP sensor. (4); The print timing correction means corrects the print timings of the forward pass and the return pass based on the recognized BR amount in order to prevent the print misalignment during the reciprocal printing. (5); the BR amount calculation means sets the mechanical HP trigger to mechanical HP by the HP sensor in one carriage driving direction, and electrically predicts the mechanical HP trigger in the other carriage driving direction. HP generation timing is electrical HP
Then, the temporal difference (HP lag) between the electrical HP and the actual mechanical HP is defined as the BR amount in (3) above.

Next, claim 2 will be described. In the embodiment of the first aspect, the HP trigger is a digital edge signal so that the HP trigger can be fetched as an interrupt signal. This is an HP lag recognition means having the following means (6) to (10). (6); The conversion means converts the HP trigger into a digital signal (digital HP trigger). (7); The CPU performs motor control, print timing control, and the like. (8); The HP lag recognition means recognizes the HP lag by the timer function of the CPU. (9); The capturing means uses a digital HP trigger as a CP.
Take in the interrupt terminal of U. (10); The processing means controls the timer function for recognizing the HP lag by an interrupt routine of software corresponding to the interrupt.

Next, claim 3 will be described. In the embodiment according to claim 2, the HP trigger is a signal whose digital level changes before and after the trigger, and the interrupt signal is input to different interrupt terminals of the CPU, so that it can be easily determined whether the interrupt signal is a forward path or a backward path. Can be identified. It is a CPU interrupt input means of a digital HP trigger having the following means (1) to (14). (11); HP sensor and HP sensor output conversion means,
The digital HP trigger is output as a falling / rising signal in which 0/1 of the digital signal changes before and after the generation. (12); The CPU has an interrupt terminal triggered by a rising edge and an interrupt terminal triggered by a falling edge. (13); The capturing means captures the digital HP trigger into the above two interrupt terminals. (14); The control means is two software interrupt routines by two interrupts, and H corresponding to each of them.
It controls the timer function for recognizing the P lag.

Next, claim 4 will be described. Even if the HP trigger is fetched into the CPU by an interrupt, it takes several [μs] time (soft lag) for the CPU to transfer the software control from the interrupt routine to the timer count start / end routine (however, the timer is started by the interrupt. / This is not the case with CPUs that can be stopped). Therefore, an error occurs in the count value accordingly. Therefore, to prevent this, this software may be stored as data in advance and corrected when calculating the HP lag. This is an HP lag correction means having the following means (15). (15); The HP lag correction means holds in advance the time required for software processing from interrupt input to timer function control by an interrupt routine as data,
Correct the HP lag value.

Next, claim 5 will be described. In addition, H
Since the appropriate range of the P lag value is determined by the mechanical design value of the system, if it is out of the range, an abnormality such as step-out of the CR motor may be considered. So HP lag
An appropriate range such as the calculated BR correction value is stored in advance, and when it is out of the range, a warning is generated and operation is stopped. It has the following drive means (16). (16); The drive means is the HP lug, B by the HP lug
An appropriate range is set in advance for the R correction value, etc., and when it goes out of the range, a warning is issued and the device is stopped. In the above description, the timer count is assumed to be the internal timer of the CPU, but it goes without saying that a timer external to the CPU may be used. Further, in the embodiment of the present invention, CR
Although the motor is a stepping motor, it goes without saying that a servo motor or the like may be used.

[0016]

As is apparent from the above description, the present invention has the following effects. (1) Effect corresponding to claim 1; Even in a system using a motor having a relatively large controllable unit such as a stepping motor, the BR correction can be performed with the accuracy of an electric circuit timer such as a CPU. (2) Effect corresponding to claim 2; The accuracy of BR correction can be improved by accepting an HP trigger by an interrupt and reducing the time lag of software processing. (3) Effect corresponding to claim 3; The accuracy of BR correction can be improved by using the digital HP trigger as a signal whose digital level changes before and after the HP trigger and reducing the software processing time for CPU interrupt determination. . (4) Effect corresponding to claim 4; The accuracy of BR correction can be improved by storing the processing time until the interrupt processing and using it for BR correction. (5) Effect corresponding to claim 5: By storing an appropriate range such as a BR correction value and performing it with electrical counter accuracy, even a minute abnormality can be detected, and accuracy such as warning and operation stop is improved. The safety of the device can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a serial printer according to the present invention.

FIG. 2 is a block diagram of a serial printer according to the present invention.

FIG. 3 is a time chart of electric signals in FIG.

[Explanation of symbols]

1 ... Recording paper, 2 ... Platen roller, 3 ... Print head, 4
... Carriage, 5 ... HP (home position) sensor (actuator), 6 ... HP (home position) sensor (fat sensor), 7 ... Carriage drive belt, 8
... CR (carriage) motor (stepping motor),
9 ... Pulley, 10 ... Central processing unit (CPU), 11 ... Digital edge signal generation unit, 12 ... Print control unit, 13 ...
Motor control unit.

Claims (5)

[Claims] 1. A sensor means for detecting a signal indicating that the carriage has passed a home position, which is a predetermined position, during operation of a carriage having a print head, and based on a sensor output from the sensor means,
A carriage motor that reciprocally drives the carriage, a recognition unit that electrically recognizes a positional deviation amount between the forward path and the return path of the carriage based on a sensor output from the sensor unit, and a print deviation during reciprocating printing, Correction means for correcting the print timing of the forward path and the return path based on the recognized positional deviation amount, and the mechanical passage signal generation by the sensor means in the one carriage drive direction is set as the mechanical home position, and the other carriage drive When the generation timing of the mechanical home position that is electrically predicted in the direction is the electrical home position, the time difference between the electrical home position and the actual mechanical home position is determined by the positional deviation in the recognition means. A serial printer characterized by comprising a calculation means for calculating a quantity. 2. A conversion means for converting the passing signal into a digital signal, a central processing means for performing motor control and print timing control, and a recognition means for recognizing the temporal difference by a timer function of the central processing means. A means for fetching the digital passing signal into the interrupt terminal of the central processing means and a processing means for controlling the timer function for recognizing the temporal difference by an interrupt routine of software corresponding to the interrupt. The serial printer according to claim 1. 3. A sensor means for outputting the digital pass signal as a falling / rising signal in which 0/1 of the digital signal changes before and after its generation, an output converting means of the sensor means, and a rising edge as a trigger. An interrupt terminal, a central processing means having an interrupt terminal triggered by a falling edge, a means for capturing a digital passing signal into the two interrupt terminals, and two software interrupt routines by two interrupts,
3. The serial printer according to claim 2, further comprising control means for controlling a timer function for recognizing the temporal difference corresponding to each of them. 4. A correction means is provided for previously holding, as data, a time required for software processing from interrupt input to timer function control by an interrupt routine, and correcting the value of the temporal difference. Two
Or the serial printer described in 3. 5. An appropriate range is set in advance for the temporal difference and the positional deviation correction value based on the temporal difference, and drive means is provided for issuing a warning and stopping the device when the range is out of the range. The serial printer according to claim 1, 2, 3, or 4.