JPS5837915B2 - Carrier return operation control device in printer - Google Patents

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a device for returning a carrier on which a print head is mounted to a home position in a short time and accurately in a serial printer. This enables accurate return operation at all times without being held up by the user.

(b) Background of the Technology In serial printers, except those capable of reciprocating printing, the print head carrier is returned to the home position after each print line after the print head finishes printing or reaches the light end. After that, the next line will be printed.

Therefore, by shortening this return operation time, the overall printing speed of the printer can be increased.

However, even when the print head returns from a far position away from the home position, if the print head returns at a low speed similar to when returning from a position close to the home position, the carrier takes too long to return, which hinders the improvement of printing speed. Become.

Therefore, when returning from a position close to the home position, it is returned at a low speed so that it can be stopped immediately without causing a shock, but when returning from a position far from the home position, it is accelerated at the time of startup and returned to an intermediate position speed. Japanese Unexamined Patent Application Publications No. 51-26114 and No. 52-135016 have proposed a control device that moves the vehicle quickly and then reduces the speed when the vehicle approaches the home position to a low speed state.

(c) Prior art and its problems However, in all of these methods, a detection switch such as a reed switch is placed in the middle of the carrier's movement path, and it is difficult to determine whether the carrier returns from a position far from the talk detection switch or if the carrier returns from a position far from the talk detection switch. It detects whether the return is from a position closer than the detection switch, and it lacks accuracy in detecting the position of a moving object.

Furthermore, regardless of when the carrier is operating normally, no measures have been taken to ensure that it returns to the home position accurately even in the event of an abnormality such as when the print head touches an obstacle. When an abnormality occurs, it is necessary to generate an abnormal signal and manually restore the normal state.
Not only is it inconvenient to handle, but it also causes a decline in printing ability.

(d) Purpose of the Invention The present invention provides an apparatus for shortening the return time of a carrier by accelerating and decelerating when the print head returns from a position far from the home position, regardless of the state of the print head. The purpose is to always ensure a return to the home position and then to be able to normally start printing the next line.

(e) Structure of the Invention In order to achieve this object, the present invention provides a device for controlling when a carrier on which a print head is mounted is returned to a home position by a carrier transport motor. When starting the speed, gradually increase the speed,
a high-speed return circuit that gradually decelerates as it approaches the home position; a low-speed return circuit that drives the carrier transfer motor at a low and constant speed; and a first left-end comparison circuit that is selected by a signal from the high-speed return circuit; a second left end comparison circuit selected by a signal from the slow return circuit; and an address for managing the print head position with an address in a logic circuit and inputting the value of the address to the fast return circuit and the slow return circuit. and a management section, and based on the address value input from the address management section and the return command of the print head, a set position far from the home position and a large address, that is, a position farther from the home position than the braking start position, is set. , for return from a set position far enough away that the acceleration at return can be completed and the steady speed can be reached, the high-speed return circuit and the first left end comparison circuit are selected to perform speed control and stop control. When returning from a position closer to the home position than the set position, the low-speed return circuit described above is selected to enable control to return the carrier at a low and constant speed, and to prevent the print head from accidentally returning. The first controller determines that the address position of the print head does not match the actual position due to movement due to an external force or the like, generates a discrepancy signal, and selects the low-speed return circuit. The left end comparison circuit is configured to input a left end detection signal and an end signal, and the mismatch signal is input to a low speed recovery circuit.

(f) Embodiments of the Invention Next, how the carrier return operation control device in a printer according to the present invention is actually implemented will be explained by way of embodiments.

FIG. 1 is a block diagram showing an embodiment of a carrier return operation control device for a printer according to the present invention.

Reference numeral 1 designates an address counter consisting of an up-down counter, which counts how many digits the carrier is on the print line, and is inputted together with the return command signal A to the high-speed return circuit 2 and the low-speed return circuit 3.

The high-speed return circuit 2 outputs a modulated signal H to the drive circuit 4 of the pulse motor 5, and controls the speed of the carrier transport motor 5 so that the speed is gradually increased at startup and gradually decelerated when approaching the home position. It is something to do.

The low speed return circuit 3 outputs a low speed drive signal L to the drive circuit 4 to control the carrier transfer motor to be driven at a low and constant speed.

It also includes a first left-end comparison circuit 7 selected by a signal from the high-speed recovery circuit 2 and a second left-end comparison circuit 9 selected by a signal from the low-speed recovery circuit 3.

A left end detection signal LE is input from the left end detector to the first left end comparison circuit 7 and a second left end comparison circuit 9, and a specific excitation phase signal Y is input from the drive circuit 4.

As described above, when the first left end comparison circuit 7 or the second left end comparison circuit 9 is selected and the carrier returns to the home position and stops, the coincidence signal OK1 or OK2 is input to the drive circuit 4. , the motor 5 is stopped.

If the address position of the carrier differs from the actual position due to a hand touching the print head, a mismatch signal NO is sent from the first left end comparison circuit 7 to the slow recovery circuit 3.
is input, and the low speed recovery circuit 3 is selected.

Next, the operation of this device will be explained.

A value indicating the position of the carrier on the address is always input from the address counter 1 to the high-speed return circuit 2 and the low-speed return circuit 3. The fast return circuit 2 or the slow return circuit 3 is selected depending on the size, that is, the distance from the home position.

If the position of the carrier is far away from the home position when the return command signal A is input, the high-speed return circuit 2 is selected.

When the fast return circuit 2 is selected, the address counter 1 controls the address to determine how many digits to return, and at the same time, a timing signal modulates the.

That is, when the address is far from the home position, start modulation is applied to gradually increase the speed, and when the address falls below a certain digit and approaches the home position, stop modulation is applied to gradually decrease the speed.

FIG. 2a shows the output signal H which has undergone such modulation.

When the high-speed return circuit 2 is activated, the drive circuit 4 is activated by the output signal H, and the four-phase carrier transfer pulse motor 5 is activated.
The carrier is driven back to its home position.

A feedback pulse P is generated from the drive circuit 4 in response to the movement of the carrier, passes through the pulse cut circuit 6, counts down the address counter 1, and when the address counter 1 indicates the home position, a feedback pulse P is generated from the high-speed return circuit 2. Outputs end signal E.

The pulse motor 5 is driven in four phases, and its drive circuit 4
Specific excitation phase signal that is output from and represents the regular digit position
1 end signal E and left end detection signal LE are input to the first left end comparison circuit 7.

In the left end comparison circuit T, when the end signal E or the left end detection signal LE is input, three signals Y,
E and LE are compared, and when the three match, a match signal OK1 is output and the drive circuit 4 is stopped.

If these three signals Y, E, and LE do not match in the left end comparator circuit 7, a mismatch signal NO is outputted, the signal is fed back to the low-speed return circuit 3, and the low-speed return circuit 3 is activated to perform the low-speed Operate the return operation.

In other words, if the carrier is moved to the right by an external force due to sudden hand contact, the address in address counter 1 and the mechanical carrier position are different, so even if the carrier is returned by the address and the end signal E is issued, The carrier will stop at a position to the right of the home position by the distance traveled by the external force.

In this case, since the left end detection signal LE is naturally not output, the three signals Y are output in the left end comparison circuit 7.
, E and LE are determined to be mismatched, and a mismatch signal NO is output.

This signal NO causes the low speed return circuit 3 to operate, and its output signal L operates the drive circuit 4 to drive the pulse motor 5.

At the same time, by inputting the output signal L to the counter controller 8, the pulse cut circuit 6 is configured to prevent the countdown feedback pulse P output from the drive circuit 4 from being input to the address counter 1 which has already indicated the home position. The feedback pulse P is cut off.

The output signals of the low-speed return circuit 3 have long intervals as shown in FIG. 2b, the return operation is performed at a speed that can be stopped immediately, and no modulation is performed at the time of starting or stopping.

Therefore, in the second left end comparison circuit 9, the excitation phase signal
1 When the left end detection signal LE and the output signal L of the low-speed return circuit 3 match, a match signal OK2 is output, and the drive circuit 4 is immediately stopped to stop the carrier.

If the carrier moves to the left, that is, closer to the home position, due to an external force, the left end detection signal LE is mechanically output before reaching the logical zero address, so at this point the left end comparison circuit 7 outputs the mismatch signal. No is output.

In this case, the address counter 1 is cleared via the counter controller 8 by the output signal L of the low-speed recovery circuit 3 activated by the mismatch signal No, and returned to the zero address.

In the left end comparison circuit 9, the first output signal L is
Since the three signals Y, LE, and L match and output the match signal OK2, the drive circuit 4 is in a stopped state.

In other words, since the logical address and mechanical carrier position do not match, and logical address management during low-speed return operation is impossible, address counter 1 is ignored and the home position is given using the left end detection signal LE. .

Next, when the return command signal A is input, if the carrier is at a small address position, that is, a position close to the home position, there is no need for high-speed return, so the address counter 1 is used from the beginning to control the low-speed return circuit 3. Select
In the same way as the above operation, ignore address counter 1,
The return operation ends upon detection of the left end detection signal LE.

In this case as well, no start-up or stop modulation is performed.

(g) Effects of the Invention As described above, according to the present invention, in an apparatus that accelerates and decelerates when the print head returns from a position far from the home position, thereby shortening the return time of the carrier,
The current position of the print head is detected from the address of the print head, and it is also detected that the current position of the print head and the address value do not match due to the print head being moved by an unexpected external force, etc. In this case, the first left end comparison circuit selects the low-speed return circuit, and from then on, the carrier returns at a low and constant speed, similar to when returning from a position close to the home position. There is.

In this way, the position of the print head is detected by the address management section without using a detection switch, so even if the print head is moving at high speed, its current position can be detected accurately. It can be stopped at the home position.

In particular, if the print head moves due to external force, the address counter value and the actual position of the print head may not match.
If the carrier position cannot be managed by the address management section, the first left end comparison circuit selects the low-speed return circuit and returns to the home position at low speed, so that the carrier does not operate normally. Even if it is not, it is possible to reliably return it to the home position and prepare for the next printing operation.

Therefore, even if the carrier position becomes abnormal, there is no need to generate an abnormal signal each time to trouble the human operator, and from this point of view as well, the printing speed can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a carrier return operation control device for a printer according to the present invention, FIG. 2a is a time chart of control pulses for returning the carrier at high speed, and FIG. It is. In the figure, 1 is an address counter, 2 is a high-speed return circuit, 3 is a low-speed return circuit, 4 is a drive circuit, 5 is a carrier transfer pulse motor, 6 is a pulse cut circuit, 7 and 9 are left end comparison circuits, and 8 is a left end comparison circuit. Each counter controller is shown.

Claims (1)

[Claims] 1. In a device for controlling when a carrier carrying a print head is returned to a home position by a carrier transport motor, the speed of the carrier transport motor is gradually increased at the time of startup;
a high-speed return circuit that gradually decelerates as it approaches the home position; a low-speed return circuit that drives the carrier transfer motor at a low and constant speed; and a first left-end comparison circuit that is selected by a signal from the high-speed return circuit; a second left end comparison circuit selected by a signal from the slow return circuit; and an address for managing the print head position with an address in a logic circuit and inputting the value of the address to the fast return circuit and the slow return circuit. and a management section, and based on the address value input from the address management section and the return command of the print head, a set position far from the home position and a large address, that is, a position farther from the home position than the braking start position, is set. , for return from a set position far enough away that the acceleration at return can be completed and the steady speed can be reached, the high-speed return circuit and the first left end comparison circuit are selected to perform speed control and stop control. When the carrier is returned from a position closer to the home position than the set position, the low-speed return circuit is selected so that the carrier can be controlled to return at a low and constant speed, and the print head can be returned inadvertently. The first controller determines that the address position of the print head does not match the actual position due to movement due to an external force or the like, generates a discrepancy signal, and selects the low-speed return circuit. A carrier return operation control device for a printer, characterized in that the left end comparison circuit is configured to input a left end detection signal and an end signal, and the mismatch signal is input to a low speed return circuit. .