JPH11268342A - Printer and control method thereof - Google Patents

Abstract

(57) [Problem] To provide a technique capable of preventing print unevenness caused by a delay or advance of a phase caused by a response characteristic of a feeding operation in a printer, and suppressing a decrease in print quality. A feed motor is supplied to a feed motor by changing a phase difference θ between a drive pulse and an energizing pulse in accordance with a feed speed that changes like an acceleration period P, a constant speed period Q, and a deceleration period R. The phase difference of the sheet feeding operation with respect to the drive pulse is compensated by the phase difference θ of the energizing pulse with respect to the drive pulse. As a result, the shift of the printing position due to the delay or advance of the sheet feeding operation is eliminated by the shift of the energization timing of the print head 19, and the print dot is formed at the original accurate position on the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly to a technique suitable for a printer having an acceleration period, a constant speed period, and a deceleration period as a feeding operation of a printing material such as paper to a print head.

[0002]

2. Description of the Related Art Conventionally, printers have often adopted a printing method in which a printhead is applied to the surface of a sheet on a platen roller while a printing object such as a sheet is fed by a platen roller. Thermal printers, inkjet printers,
There is a dot impact printer and the like. In this type of printer, usually, the print head is fixed and the print head is operated in accordance with the amount of paper being fed while the paper is fed by the platen roller.

In the above-mentioned printers, the print head has an energizing pulse for heating the head in the case of a thermal printer, a driving pulse for ejecting ink in an ink jet printer, and a pin in the case of a dot impact printer. It is necessary to send a drive pulse for each. These energizing pulses and drive pulses are usually supplied to the print head in accordance with drive pulses of a stepping motor for rotating the platen roller.

[0004]

When the platen roller is driven to rotate, if the rotation speed of the stepping motor is increased at one time, paper misalignment or mechanism damage is likely to occur. An acceleration period is provided in which the rotation speed is gradually increased (slow-up) by gradually narrowing the step operation interval of the stepping motor, and when the speed reaches a predetermined speed, the platen roller is fed at a constant speed (constant speed). Period), and gradually decelerates (slow down) when print data is running low
After a deceleration period is set, the feed operation is stopped.

In such a control system, it is necessary to appropriately perform a printing operation by the print head even during an acceleration period or a deceleration period in order to ensure continuity of printing.
However, there is a predetermined time lag between the control time of the stepping motor and the actual feeding operation. In particular, during the acceleration period, the higher the acceleration, the more the response of the feeding operation is delayed, and during the deceleration period, the deceleration is reduced. The higher the value, the more the deceleration of the feed operation is delayed, and the more the response characteristic is advanced.

Further, when a platen roller is used as the feeding means, the platen roller is usually made of a material such as rubber having flexibility. At the end, a change in the transport position occurred due to the restoration of the deformation of the platen roller, which also caused an error between the motor drive signal and the printing paper position.

As a result, if the control signal for performing the printing operation by the print head and the drive signal of the stepping motor are to be periodically executed in synchronization with each other, the phase delay caused by the response characteristic of the above-described feeding operation is caused. Or, the advance causes a timing deviation between the printing operation and the feeding operation. Therefore, a boundary region between the acceleration period and the constant speed period during the feeding operation, a boundary region between the constant speed period and the deceleration period, or
In areas where the speed of the feeding operation changes, such as an area where the speed stops after the deceleration period and the acceleration period starts again, print unevenness such as a change in the density of print dots printed on the printing medium occurs, and the print quality is reduced. There is a problem of spoiling.

Accordingly, the present invention has been made to solve the above problems, and has as its object to prevent printing unevenness caused by a phase delay or advance caused by a response characteristic of a feeding operation.
It is an object of the present invention to provide a technique capable of suppressing a decrease in print quality.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a printer according to the present invention moves a print head for printing on a recording medium and relatively moves the print head and the recording medium. Sending means, and a control means for sending a movement signal to the sending means at a predetermined timing and sending an energizing signal to the print head at a timing based on the predetermined timing for printing, the control means comprising: A printer configured to control the acceleration and / or deceleration of the feed unit by changing the interval of the predetermined timing, wherein the control unit outputs an energization signal to the print head in response to a movement signal to the feed unit. Is changed in accordance with a change in the transmission timing interval of the movement signal.

According to this, by changing the phase relationship between the control timing of the printing operation and the control timing of the feeding operation by the control means, the change in the shift amount of the printing position due to the response characteristic of the feeding operation is changed. Is reduced, the accuracy of the printing position can be improved, and the printing quality can be improved.

Here, the sending means is means for intermittently executing a step operation of a predetermined distance in accordance with the movement signal based on a predetermined response characteristic, and the control means sets the phase difference in response to the response signal. It is preferable to be configured to change according to the characteristics.

According to this means, since the feeding operation is performed by a plurality of step operations, the phase difference between the control timing of the printing operation and the control timing of the step operation changes according to the change in the response characteristic of the feeding operation. By doing so, it is possible to reliably reduce the deviation of the printing position.

Further, the control means sets the phase difference in the delay direction when changing the interval of the predetermined timing for sending the movement signal to the sending means and performs the deceleration control. Is preferably configured to be set in the advancing direction.

According to this means, during the acceleration period and the deceleration period, the acceleration of the feeding operation is increased, so that the change in the response characteristic of the feeding operation is increased and the shift amount of the printing position is also increased. By performing the control for the printing operation on the head unit in accordance with the delay or the advance, the deviation of the printing position can be reduced more effectively.

In these printers, the control means has a table showing a relationship between a phase difference between an energization signal to the print head and a transmission timing of the movement signal with respect to the movement signal to the feeding means. It is preferable that the transmission timing of the energization signal is determined based on the table according to the transmission of the signal. This makes it possible to easily determine the transmission timing of the energization signal.

In these cases, the print head has a thermal head that generates heat in response to the energization signal, and the control means adjusts the width of the energization signal in response to a change in the transmission timing interval of the movement signal. Preferably, it is configured to change.

In changing the temporal relationship between the control timing of the printing operation and the control timing of the feeding operation, either the control timing for the head unit or the control timing for the feeding means may be changed, and both of them may be changed. May be.

The response characteristics of the feed operation to the control of the feed means include, for example, the amount of delay or advance of the actual feed operation timing with respect to the drive signal sent by the control means to the feed means, or It refers to the amount of delay or advance of the rotation of the platen roller with respect to the rotation of the feed motor used as the feeding means.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the configuration of an embodiment of a printer according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic block diagram showing the overall configuration of the printer of the present embodiment. Although the printer 10 shows an example in which the present invention is applied to a thermal line printer, the present invention is not limited to a thermal printer or a line printer, but may be a dot impact printer, an ink jet printer, or a serial printer. The present invention can be applied to various printers such as a printer.

The printer 10 includes a control unit 10A for controlling the input / output of data and the operation of each unit of the drive unit, and a drive unit having a paper feed, a print head, and a drive mechanism for the print head if necessary. 10B.

The control unit 10A includes a CPU 11 having a built-in timer 11a, and a ROM 1 connected to the CPU 11.
2. RAM 13A and image buffer 13B, CP
An input / output circuit 14 connected to U11;
And a motor driver 15 and a head driver 16 which are connected to each other. On the other hand, the drive unit 10B includes a feed motor 1 for feeding a sheet connected to a motor drive driver 15.
7 and a head driving I connected to the head driver 16.
C18 and a thermal print head 19 connected to and fixed to the head drive IC 18.

The print head 19 includes a head drive IC 18
A number of heating elements (not shown) connected to the front end of a flexible wiring board (not shown) attached to the printer and arranged along the printing line, and a temperature sensor 19a arranged near the arrangement of these heating elements And The temperature sensor 19a is connected to the input / output circuit 14 of the control unit 10A.

The feed motor 17 is a stepping motor, and is step-driven by a drive signal (pulse) supplied from the motor drive driver 15. FIG. 2 shows a change over time of a relative speed (hereinafter, simply referred to as “feed speed”) between the sheet fed by the feed motor 17 and the print head. When printing is started, the feed motor 1
7 gradually increases the speed according to the drive signal (acceleration period P), and when the speed reaches a predetermined speed, the operation continues at a constant speed (constant speed period Q). Further, when the number of remaining print lines decreases, the feed motor 17 decelerates again (deceleration period R).
Stops soon. The feed speed in the constant speed period Q is constant during a series of operations T from the start of the operation of the feed motor 17 to the stop thereof. Further, the acceleration period P and the deceleration period R are always fixed times, but the time of the constant speed period Q becomes longer or shorter according to the number of print lines (print data amount).

FIG. 2 shows that the feed rate is continuously changed for the sake of explanation, but actually the feed operation is intermittently performed based on the step operation of the feed motor 17. . Therefore, in the acceleration period P and the deceleration period R, the control unit 10A controls so that the interval between the step operations of the feed motor 17 changes with time.
The acceleration period P and the deceleration period R usually correspond to a time corresponding to several steps of the feed motor 17.

FIG. 2 shows an example of print dots together with the above-mentioned change in the feed speed over time. Acceleration period P and deceleration period R
In, since the feed speed changes with time, the control unit 10A changes the printing time interval in accordance with the change in the feed speed, and controls so that dots are printed at regular intervals on the paper. That is, the printing time interval is inversely proportional to the feed speed.

FIG. 3 shows a feed motor 1 according to this embodiment.
One drive pulse of the drive signal supplied to 7 (the drive signal is composed of a plurality of drive pulses having different phases to be supplied to a plurality of drive coils, and one drive pulse among them is shown as a representative. 3) and the change over time of the energizing pulse supplied to the print head 19. Each time the drive pulse is inverted, the feed motor 17 performs a step operation, and a rotation operation at a predetermined angle is transmitted to a platen roller for feeding a sheet via a transmission wheel train. Then, the heating element of the print head 19 generates heat based on the energizing pulse, and printing is performed. Here, the difference between the control timing for inverting the drive pulse and the control timing for starting energization by the energization pulse is shown as a phase difference θ. That is, the phase difference θ
Is calculated by subtracting the phase at the start of energization of the energization pulse from the phase at the inversion of the drive pulse.

The phase difference θ between the driving pulse and the energizing pulse is
It is the smallest negative value at the beginning of the acceleration period P. At this time, the energizing pulse is supplied after the drive pulse. The phase difference θ gradually increases with time, and after entering the constant speed period Q, a negative phase difference having a fixed small absolute value continues. When the constant speed period Q ends and the deceleration period R begins, the energizing pulse starts earlier than the drive pulse, and the phase difference θ becomes a positive value, and its absolute value increases with time.

FIG. 4 shows the phase difference φ between the drive pulse supplied to the feed motor 17 and the feeding operation of the sheet fed by the platen roller together with the graph of the feeding speed in the above-described series of operations. . This phase difference φ
Indicates a value obtained by subtracting the phase during the step operation of the sheet from the phase when the drive pulse is inverted.

When the driving pulse is inverted, the feed motor 17 performs a step operation, and accordingly, a platen roller for feeding the paper rotates, and the rotation of the platen roller feeds the paper. However, since the torque generated by the step motor is generated according to the phase difference, there is always a certain delay between the drive pulse and the paper feeding operation even at the constant speed feeding in the state where the load torque exists. When the feed speed is present and the feed speed changes (acceleration is present), the delay amount also changes. In particular, when the acceleration changes discontinuously, the phase difference φ between the drive pulse and the sheet feeding operation also changes discontinuously.

In this example, when the acceleration period P starts,
Because the platen roller that had been stopped until then is driven rapidly, the phase difference φ becomes a large negative absolute value, and the paper feeding operation gradually catches up with the driving pulse as the feeding speed gradually increases. The phase difference φ gradually approaches zero. In the constant speed period Q, since the driving pulses are also at constant time intervals, a negative phase difference having a small absolute value for a slight time lag is maintained. In the deceleration period R, the time interval of the drive pulse gradually increases so as to decelerate the platen roller. Therefore, the sign of the phase difference φ is inverted, becomes positive, gradually increases, and the drive pulse stops. It becomes the maximum at the time of doing. The change in the phase difference differs according to the setting of acceleration during acceleration and deceleration, but the absolute value of the phase difference is larger than that at the time of constant speed. This is because acceleration occurs according to the phase difference.

In this embodiment, the phase difference φ between the drive pulse of the feed motor and the sheet feeding operation in the process from the acceleration period P shown in FIG. 4 to the deceleration period R via the constant speed period Q is calculated. Parameters or tables are stored in the ROM 12 in advance. These parameters and tables are calculated based on experimentally measured data. Here, when the control timing of the feed motor (for example, when the drive pulse is inverted) is tabulated and recorded for each of the acceleration period P, the constant speed period Q, and the deceleration period R shown in FIG. In correspondence with the table, the phase difference φ may be tabulated for each of the acceleration period P, the constant speed period Q, and the deceleration period R.

Normally, the times of the acceleration period P and the deceleration period R, and the acceleration and the deceleration are set to be constant, and only the time of the constant speed period Q changes depending on the case. Based on the start time of period R,
The subsequent phase difference φ can be sequentially calculated or referred to. Based on the calculated phase difference φ, the CPU 11
Performs processing such that the generation timing of the energizing pulse is shifted with reference to the inversion timing of the driving pulse so that the phase difference θ between the driving pulse and the energizing pulse becomes equal to the phase difference φ.

In this manner, the phase difference φ of the sheet feeding operation with respect to the driving pulse is compensated by the phase difference θ of the energizing pulse with respect to the driving pulse, and the printing position resulting from the delay or advance of the sheet feeding operation is obtained. The offset is offset by the offset of the energization timing of the print head 19, and a print dot is formed at an original accurate position on the sheet. In particular, the acceleration period P of the feed operation in which the delay and advance of the feed operation become large, and the period before and after the acceleration period, and
Since an accurate printing position can be obtained even during the deceleration period and before and after the deceleration period, the printing quality can be improved.

In the present embodiment, the phase difference φ between the drive pulse for driving and controlling the feed motor 17 as the feed means and the feed operation of the paper as the printing medium is represented by the drive pulse and the heat generated by the print head 19. By adjusting the phase difference θ between the power supply pulse for heating the body and the phase difference θ, the shift of the printing position due to the response characteristic associated with the feeding operation has been substantially canceled. In particular, since the thermal head according to the present embodiment is pressed against the sheet, a frictional load is applied to the sheet during printing. Therefore, the platen roller and the sheet are moved by the frictional load and the step operation by the feed motor. And a feed misalignment occurs. Once
When a feed shift occurs, the frictional force between the platen roller and the paper fluctuates between static friction and dynamic friction, so that the feed shift has a complicated appearance. Therefore, it is particularly important to compensate for a feed deviation between the platen roller and the sheet.

However, the gist of the present invention is to reduce the deviation of the printing position based on the response characteristic of the feeding operation in which the print head and the printing medium move relatively to the control timing of the feeding operation to the feeding means. .

Therefore, as a response characteristic, in a situation where the feed deviation between the platen roller and the sheet does not matter, the electromagnetic response characteristic such as the operation delay of the feed motor or the output of the feed motor is simply used. A mechanical response characteristic such as a transmission delay from the transmission to the platen roller through the transmission wheel train may be theoretically obtained.

Further, in the present invention, it is not necessary to completely offset the printing position shift caused by the change in the response characteristic of the feeding operation as in the above-described embodiment, and the printing direction shift is reduced. What is necessary is just to control so that it may be changed.

[0038]

As described above, according to the present invention, the following effects can be obtained.

According to the first aspect, the control means changes the temporal relationship between the control timing of the printing operation and the control timing of the feeding operation, thereby shifting the printing position due to the response characteristic of the feeding operation. Since the change in the amount is reduced, the accuracy of the printing position can be improved, and the printing quality can be improved.

According to the second aspect, since the feeding operation is performed by a plurality of step operations, the phase difference between the control timing of the printing operation and the control timing of the step operation is determined according to the change in the response characteristic of the feeding operation. By making the change, it is possible to reliably reduce the deviation of the printing position.

According to the third aspect, during the acceleration period and the deceleration period, the acceleration of the feeding operation increases, so that the change in the response characteristic of the feeding operation increases and the shift amount of the printing position also increases. By performing the control for the printing operation on the head unit in accordance with the delay or advance of the printing, the deviation of the printing position can be reduced more effectively.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram illustrating a schematic configuration of an embodiment of a printer according to the present invention.

FIG. 2 is a diagram illustrating an example of a time change of a feeding speed and a timing of forming a print dot in the embodiment.

FIG. 3 is a diagram illustrating a temporal change of a drive pulse supplied to a feed motor and an energizing pulse supplied to a print head in the embodiment, together with a phase difference θ between the drive pulse and the energizing pulse.

FIG. 4 is a diagram showing a change over time in a feeding speed and a phase difference φ between a driving pulse and a sheet feeding operation in the embodiment.

[Explanation of symbols]

Reference Signs List 10 printer 11 CPU 17 feed motor 19 print head θ phase difference between drive pulse supplied to feed motor and energizing pulse supplied to print head φ position between drive pulse supplied to feed motor and paper feeding operation Difference

Claims (10)

[Claims] 1. A print head for performing printing on a recording medium, sending means for relatively moving the print head and the recording medium, and sending a movement signal to the sending means at a predetermined timing. And control means for performing printing by transmitting an energization signal to the print head at a timing based on the predetermined timing, the control means changing the interval of the predetermined timing to accelerate and accelerate the feeding means. And / or a printer configured to perform deceleration control, wherein the control means determines a phase difference between a power supply signal to the print head and a phase difference between the energization signal to the print head with respect to a movement signal to the feeding means in accordance with a change in a timing interval for sending the movement signal. A printer configured to change. 2. The printer according to claim 1, wherein the feeder is a unit that intermittently executes a step operation of a predetermined distance in accordance with the movement signal based on a predetermined response characteristic, And a printer configured to change the phase difference according to the response characteristic. 3. The printer according to claim 1, wherein the control unit changes the phase difference in a delay direction when changing the interval of the predetermined timing for sending a movement signal to the sending unit and performing acceleration control. The printer is configured to be set in the leading direction when deceleration control is performed. 4. The printer according to claim 1, wherein the control unit transmits a phase difference between an energizing signal to the print head with respect to a moving signal to the feeding unit and transmitting the moving signal. A printer having a table showing a relationship with timing, and configured to determine the transmission timing of the energization signal based on the table according to the transmission of the movement signal. 5. The printer according to claim 1, wherein the print head includes a thermal head that generates heat according to the energization signal, and the control unit controls the energization signal. A printer characterized in that the width is changed according to a change in the transmission timing interval of the movement signal. 6. A method for controlling a printer having a print head for performing printing on a recording medium, and a feeding unit for relatively moving the print head and the recording medium, wherein the feeding unit includes: Sending a movement signal to the print head at a predetermined timing; sending an energization signal to the print head at a timing based on the predetermined timing to perform printing; and changing the interval of the predetermined timing to the sending means. Controlling the acceleration and / or deceleration of the print signal. (A) The phase difference between the energization signal to the print head and the movement signal to the feeding means is determined according to a change in the transmission timing interval of the movement signal. A method for controlling a printer, the method comprising: 7. The printer control method according to claim 6, wherein the feeding unit is a unit that intermittently executes a step operation of a predetermined distance according to the movement signal based on a predetermined response characteristic, In the step (a), a method of controlling a printer, wherein the phase difference is changed according to the response characteristic. 8. The method for controlling a printer according to claim 6, wherein the step (a) comprises: (a1) performing acceleration control by changing an interval of the predetermined timing for sending a movement signal to the feeding means. Setting the phase difference in the delay direction; and (a2) setting the phase difference in the leading direction when deceleration control is performed by changing the interval of the predetermined timing for sending the movement signal to the sending means. A method for controlling a printer, comprising: 9. The control method for a printer according to claim 6, wherein: (b) a phase difference between an energizing signal to the print head with respect to a moving signal to the feeding means and a difference between the phase of the moving signal and the moving signal. A step of relating the transmission timing with the transmission timing. In the step (a), determining the transmission timing of the energization signal based on the relation in the step (b) in response to the transmission of the movement signal. Characteristic printer control method. 10. The printer control method according to claim 6, wherein the print head includes a thermal head that generates heat in response to the energization signal. Wherein the width of the energization signal is changed according to a change in the transmission timing interval of the movement signal.