JPS5839076B2 - Serial printer control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a serial printer control method for performing carriage return of a print head by driving a pulse motor.

As a control method of this kind, so-called feedback control is known, in which means is provided to generate a pulse every time the pulse motor rotates by a predetermined amount, and this pulse is fed to the control system to advance the excitation phase of the pulse motor. There is.

According to such feed bank control, the print head can be returned quickly without causing step-out of the pulse motor drive, but when the print head returns, the print head may temporarily stop due to some reason such as foreign matter coming into contact with the print head. Then, the feedback pulse is not generated, and therefore, even if the cause of the blockage of the print head is removed, the return operation of the print head cannot be resumed.

The present invention has been made in view of this point, and in the above-mentioned feedback control, even if the print head stops during carriage return, if the cause of the print head movement blockage is removed, the print head automatically stops moving. This allows the return operation to be resumed.

The present invention will be explained below with reference to Examples.

FIG. 1 schematically shows the serial printer of this embodiment.

A print head 4 is mounted on a wire 3 stretched along the print line between IJ-1 and IJ-2, and a pulley 2
The print head 4 is moved left and right by the rotational force of a pulse motor 5 directly connected to the print head 4 .

The print head 4 is moved forward in order of digits to the right from the initial position located at the leftmost end of the print line, performs printing at each digit position, and is rapidly returned to the initial position after printing the top digit.

If the printing format is, for example, a thermal printing format, the print head 4 has a heat-generating print surface for one digit formed by forming a plurality of heat-generating donts in a matrix arrangement, and during printing, the print head 4 is formed into a character pattern. Printing is performed by generating heat and pressing it against heat-sensitive printing paper.

Now, P is the initial position of the print line.

Then, the initial position P.

An initial position detector 6 is disposed at the position P1, and a deceleration position detector 7 is disposed at a position P1 slightly to the right of the initial position detector 6. When the print head 4 is located at each position p1 and po, the detectors 7 and 6 Generates a deceleration signal SD and a stop signal SQL.

The detectors 6, 7 can be composed of demagnetizing elements, for example, and in this case, the print head 4 is located at each position P at the center of the back surface of the print head 4.

. A slit disk 8, which is directly connected to the pulse motor 5, closely faces each of the detectors 6 and 7 when positioned at Pl, and has a magnet attached thereto for energizing it. It has slits 9 at the same angular arrangement.

The photointerrupter 10 includes a pair of light sources and a light receiving element that face each other with the periphery of the slit disk 8 in between. A varnish lint pulse SLP is generated every rotation of the stelaph.

The control circuit 11 drives and controls the pulse motor 5 to move the print head 4 forward and back.

At this time, the control technique during the forward transport is similar to the known technology, but the return transport, ie, that of the carriage return, is in accordance with the present invention.

When the carriage returns, the control circuit 11 effectively uses the slint pulse SLP, the deceleration signal SD, and the stop signal SQL to control the pulse motor 5 as outlined below.

When a carriage return command signal CRMS for commanding the carriage return of the print head 4 is applied from the outside, the control circuit 11 drives the pulse motor 5 to perform the return of the print head 4.

Once this drive is started, the control circuit 1 controls the slit pulse SL generated from the photointerrupter 10.
Based on P, the excitation phase for the pulse motor 5 is advanced, thereby executing the return of the print head 4 at an accelerated rate, so that its return speed is rapidly increased.

When the print head 4 reaches the position P1, a deceleration signal SD is generated, and upon receiving this signal, the control circuit 11 immediately starts decelerating the return speed of the print head 4.

The print head 4 is at the initial position P. When the stop signal SQ is reached, the stop signal SQ
L is generated, and the control circuit 11 receives this signal and stops the carriage return operation.

When the print head 4 stops for some reason during the carriage return, the control circuit 11 senses that slit pulses are not generated at predetermined time intervals and generates a forced drive pulse, which causes the pulse motor 5 to Initiate the return action again.

FIG. 2 shows the control circuit 11. In particular, details of the carriage return control part are shown.

The pulse motor drive circuit 12 applies an excitation pulse to the pulse motor 5, and at this time, the drive pulse MP input to the circuit
The excitation phase is advanced by one step each time the signal is received.

The motor drive pulse MP is transmitted through the first to fourth differentiating circuits 13 to 1.
6.

That is, the drive pulse MP at the time of startup due to the arrival of the carriage return command signal CRMS is generated via the first differentiator circuit 13, the drive pulse MP when the print head 4 is accelerated and returned is generated via the second differentiator circuit 14, and the drive pulse MP is generated when the print head is decelerated and returned. are generated through a third differentiating circuit 15, and the above-mentioned forced drive pulse is generated through a fourth differentiating circuit 16.

Each of the first to fourth differentiating circuits 13 to 16 is an inverter,
It has a well-known configuration consisting of a Nandt gate, a resistor, and a capacitor, and after differentiating the rising edge of an input pulse, outputs the polarity inverted, and also generates a high-level output when there is no input pulse.

The selection of the husband's signal path passing through the first to third differentiating circuits 13 to 15 is determined by the logic states of the first to third bistable multis 17 to 19, and the logic states are initially in the reset state. Yes, after that carriage return command signal CR
MS, deceleration signal SD, or stop signal SQL.

The selection of the signal path passing through the fourth differentiating circuit 16 is based on the driving pulse M.
It is determined by the time interval between occurrences of P.

The configuration and operation of the control circuit 11 will be further explained below with reference to the signal waveform diagrams of FIGS. 3 and 4.

[1] When the carriage return is performed normally (see Figure 3).

When the carriage return command signal CRMS is input, the first bistable multi 17 is set, and its set output CRM becomes high level.

This output CRM holds AND gates 20 and 21 open, respectively.

On the other hand, the output CRM passes through the first differentiating circuit 13 to produce a negative polarity pulse MC4, and this pulse signal is passed through the Nant gate 22.
Then, it passes through the AND gate 21 and becomes the drive pulse MP.

Therefore, the pulse motor drive circuit 12 advances the excitation phase for the pulse motor 5 by one step, and the pulse motor 5
Accompanying this, the print head 4 rotates by one step and moves the print head 4 by one step in the direction of the initial position a.

This step rotation of the pulse motor 5 is a slit pulse S.
Generates LP.

The slit pulse SLP passes through the AND gate 20 and the second
The pulse S passes through the differentiating circuit 14 and further passes through the inverter 23.
It becomes LP'.

Subsequently, the pulse S'LP' passes through the Nant gate 24 which is in an open state due to the high level reset state S'DM of the second bistable multi 18, and then becomes a negative polarity pulse MC.

This pulse passes through the gate 22 and the gate 21 and becomes the drive pulse MP.

Therefore, the pulse motor drive circuit 12 advances the excitation phase of the pulse motor 5 by one step further, and the pulse motor 5V'i rotates accordingly to move the print head 4 by one more step.

In this way, the slit pulse SLP and drive pulse MP are generated repeatedly as the pulse motor 5 rotates, and as a result, the pulse motor 5 accelerates its rotational speed and returns the print head 4 rapidly.

The return of the print head 4 causes the head to move to position P1.
When the deceleration signal SD is generated, the second bistable multi 1
8 is set, and its set output SDM and reset output SDM become high level and low level, respectively.

The low level reset output SDM connects the Nantes gate 24! The gate 25 changes from the open state to the closed state, while the cent output SDM at the crystal level changes the Nantes gate 25 from the previously closed state to the open state.

Therefore, the pulse SLP' after the deceleration signal SD is generated passes through the open Nant gate 25 and triggers the first monostable multi 26, and the reset output MC01 of the multi passes through the third differentiator 15 and becomes negative polarity. It becomes a signal pulse block, and further passes through a Nant gate 22 and an AND gate 21 to become a drive pulse MP.

The first monostable multi 26 is centered and reset by the falling and rising edges of the trigger pulse, respectively.

The cent state of the first monostable multi 26 is automatically reset after a certain period of time by the time constant of its own time constant circuit, independently of the reset operation by the trigger pulse.

Immediately after the deceleration signal SD is generated, the first monostable multi 26 is reset by the next pulse SLP' before being automatically reset by its time constant.

That is, immediately after the deceleration signal SD is generated, the pulse motor 5 is in a rapid rotation state, and the time at which the next slit signal SLP is generated due to its inertial rotation is determined by the time constant of the first monostable multi 26. This is to ensure that you arrive within the specified time.

What should be noted here is that in such a case, the slit pulse SLP
The generation of is based on the inertial rotation of the pulse motor 5, and the first
The pulse S LP' that first triggered the monostable multi 26
does not lead to the generation of the drive pulse MP, and therefore, the excitation phase always advances with respect to the rotation step position of the pulse motor 5 during acceleration at that point 1, but it hardly advances after the deceleration signal is generated. , the time interval between the occurrences of the slit pulse SLP gradually becomes longer.

Therefore, the pulse motor 5 gradually decelerates after the deceleration signal SD is generated, and finally the time interval between the generation of the slit pulses SLP becomes longer than the time determined by the time constant of the first monostable multi 26, and thereafter the above-mentioned automatic reset is performed. By operation, the first monostable multi 26 comes to generate the reset output Mwest after a certain period of time after receiving the pulse SLP'.

Therefore, as this state continues, the pulse motor 5 starts rotating at a constant speed.

The print head 4 is at the initial position P.

When it reaches , a stop signal SQL is generated.

In reality, the detection range of the detector 6 expands to some extent, and the signal SQL is output to the AND gate 2 within such a detection period.
7, the third bistable multi 1'9 is set in synchronization with the slit pulse SLP passing through the OR gate 28, and its set output SOLM is turned to a high level.

Such set output SOLM then resets the first and second double-described multis 1γ,18.

When the first bistable multifunction device 17 is reset, the AND gate 20 is closed, and thereafter the transmission of the slit pulse SLP is cut off by the AND gate 20, so that the drive pulse MP is no longer generated, and the print head 4 returns to the initial position P.

Stop nearby. Thereafter, when a new first digit spacing command signal is generated, a signal SOLMReset is generated, and the third bistable multi 19 is reset.

[2] When the movement of the print head 4 is blocked for some reason during the carriage return and the print head 4 stops (see FIG. 4).

) On the one hand, the drive pulse MP is the second monostable multi 29
is triggered.

The multi is centered at the falling edge of the trigger pulse, and its cent state is automatically reset after a certain period of time by the time constant of its own time constant circuit.

The time constant time is the time constant time of the first monostable multi 26 and the slit pulse S at the time of starting the pulse motor 5.
This is set to be sufficiently longer than the time interval between LP occurrences.

Therefore, after the arrival of the carriage return/command signal CRMS, the drive pulses MP are generated one after another within the above-mentioned time constant time of the second monostable multi 29 while the carriage return is being performed normally. The monostable multi 29 maintains the cent state.

However, as shown in Figure 4, for some reason the print head 4
When the slit pulse SLP stops, for example, the slit pulse SLP is no longer generated after the third view.

At this time, the second monostable multi 29 changes to the reset state after the lapse of the time constant time after the arrival of the third slit pulse SLP.

Such a change in the reset output MCO2 of the second monostable multi 29 is caused by a negative polarity signal pulse MC5 via the fourth differentiator 16.
Then, the signal is a Nant gate 22 and an AND gate 21.
After that, it becomes the drive pulse MP.

This pulse MP is hereinafter referred to as a forced drive pulse.

The strong control drive pulse MP triggers the second monostable multi 29, so that after the time constant of the second monostable multi 29, the forced drive pulse MP is generated again.

Thus, while the movement of the print head 4 is blocked, the slit pulse SLP is not generated, but the forced drive pulse MP continues to be generated at predetermined time intervals due to the action of the second monostable multiplier 29.

When the cause of the movement of the print head 4 is removed in such a state, the pulse motor 5 returns to operation using the forced drive pulse MP formed by the action of the second monostable multi 29 and the fourth differential circuit 16 as a starting pulse. Start.

When the pulse motor 5 starts the return operation, the slit pulse SLP is generated again, so that the printer thereafter operates in the same manner as in the normal carriage return operation described above.

In the above control circuit, due to the action of the second monostable ÷ multi 29,
Even if the photointerrupter 10 fails and the pulse motor continues to rotate, SLP does not occur at all, drive pulses MP are generated at intervals of the second monostable multi 290 time constant. As a result, the pulse motor 5 performs a return operation, albeit at a low speed.

This return operation causes the print head 4 to return to the initial position P.

When the output pulse signal MC6 of the fourth differentiating circuit 16 reaches
enters the AND gate 27 via the inverter 30 and the OR gate 29.

At this time, the AND gate 27 is open due to the stop signal SQL, and therefore the third bistable multi 19 is sent, and the first
The bistable multi 17 is reset, the AND gate 21 is closed, and the forced drive pulse MP is generated by the second monostable multi 29.
will no longer occur.

As is clear from the above explanation, according to the present invention, even though the pulse motor is feedback-controlled when the print head makes a carriage turn using the driving force of the pulse motor, the print head stops midway through the carriage turn. However, if the cause of the print head movement blockage is removed, the return operation of the print head will be automatically resumed. Therefore, each time the print head stops, the state of the printer must be manually reset to initialize the print head. No need to return to position.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a serial/printer according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a control circuit constituting the embodiment, and FIG.
4 and 4 are signal waveform diagrams for explaining the operation of the same embodiment. 4... Print head, 5... Pulse motor, 8... Slit plate, 11... Control circuit.

Claims (1)

[Claims] 1. In the printer control method for controlling the print head by the driving force of the pulse motor, the pulse SL is activated every time the pulse motor rotates by a predetermined amount.
P, the excitation phase of the pulse motor is advanced based on the pulse SLP, and if the generation time interval of the pulse SLP does not occur within a predetermined time, after the predetermined time elapses. A serial printer control method, comprising means for generating a forced drive pulse, the forced drive pulse advancing the excitation phase of the pulse motor.