JPS61116552A - Printing system of dot printer - Google Patents

Abstract

PURPOSE:To accurately hold the intervals between dots, by supplying a driving current to a printing head after the elapse of the time from the point of time, when the driving current for rotating a pulse motor is changed over, to a time before a printing mechanism or a printing paper feed mechanism arrives a regular position. CONSTITUTION:When an exciting phase is changed over from a B phase to a CD phase, a processor 4 changes over the exciting phase as shown by the arrow in the rising of a timer and interruption is applied to the processor 4 in the rising of a timer 20 after Nms was elapsed. The processor 4 starts the supply of a current to a thermal head 13 and stops the supply of a current to said thermal head 13 on the basis of interrption due to rising after 1ms was elapsed. Nms is set to a time calculated by subtracting the current supply time of a printing head from the exciting phase change-over cycle of the pulse motor 15 or a time shorter than said time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a serial or line type dot printer, and in particular to a dot printer that uses a pulse motor to feed the print head or print paper and prints without run-up or overrun. Regarding the printing method.

In recent years, with the spread of information processing devices, various printers have been developed and put into practical use. However, a pulse motor is used to feed the print head or print paper, and the print head is energized in synchronization with this pulse motor to print characters and print. Dot printers that express figures and the like in dot matrices are often used.

Among these dot printers are serial printers that print by moving the dot to print without run-up or overrun.
Alternatively, there is a line printer that prints by feeding printing paper without run-up or overrun.

In these dot printers, when not printing, the print head or paper is stopped, and when printing, the pulse motor is started and printing starts. Therefore, it is necessary to start printing without waiting for the moving speed of the print head or paper feed mechanism to become constant, but without degrading print quality.

[Conventional technology]

FIG. 4 is a block diagram of a circuit showing an example of a thermal transfer printer.

The processor 4 reads the program stored in the ROM 2 and operates. Print data is sent from the host device via the input/output port 1. The processor 4 temporarily stores this print data in the RAM 3.

The processor 4 determines the home position of the thermal head 13 based on the information input from the sensor 18 via the input port 12, and the processor 4 determines the home position of the thermal head 13 based on the information input from the switch 17 via the input port 12, for example, when the switch 17 is closed, the output port 5 The driver 9 is driven through the magnet 1-1.
An excitation current is supplied to 4 to press the thermal head 13 together with the printing paper onto the platen via the thermal transfer ribbon, thereby preparing to print on the printing paper.

When the processor 4 extracts a character code from the print data read from the RAM 3, it reads a character pattern from a character generation circuit (not shown), drives the driver 8 via the output port 5 in correspondence with the dots forming this character pattern, and The thermal head 13 is energized and heated.

FIG. 5 shows an example of a detailed circuit of the thermal head 13 and driver 8.

For example, if a character is composed of 24 dots, when a signal to drive the transistor TRI is input to the terminal a, the transistor TRI is turned on, so the transistor TR2 is also turned on, and the head H1 forming one dot of the thermal head 13 is turned on. is heated by the current flowing from the power supply (2) through the head H1 to the transistor TR2.

Similarly, when a signal for driving the transistor TR3 is input to the terminal S, the transistors TR3 and TR4 are turned on and the head H2 is heated. Also, when a signal to drive the transistor TR5 is input to the terminal X, the transistors TR5 and TR13
is turned on, and the head H24 is heated.

At the same time, the processor 4 drives the driver 10 via the output port 5, supplies a drive current to the space motor 15, and controls the space of the thermal head 13.

FIG. 6 shows an example of a detailed circuit of the space motor 15 and driver 10.

This example shows a drive circuit when the space motor 15 is a 4-phase pulse motor, and the space motor 15 includes A, B, C,
It rotates by sequentially exciting each phase of D.

When a signal to drive the transistor TR7 is input from the terminal fa), the transistor TR7 is turned on, so the transistor TR8 is turned on, and the A phase of the space motor 15 is excited by the current flowing from the power supply V through the A phase and through the transistor TR8. Ru.

Similarly, when a signal for driving the transistor TR9 is input from the terminal fbl, the transistors TR9 and TR10 are turned on, and the B phase is excited. Also, a transistor T is connected to the terminal (C).
When a signal to drive RII is input, transistor TRII
, TR12 is turned on, and the C phase is excited. Further, when a signal for driving the transistor TRl3 is input to the terminal (d+), the transistors TR13 and TR14 are turned on, and the D phase is excited.

When a line feed command is extracted from the print data read from the RAM 3, the processor 4 drives the driver 11 through the output port 5, supplies a drive current to the line feed motor 16, and feeds the printing paper.

The processor 4 sets a time in a timer 6 to obtain the timing for switching each of the excitation phases of the space motor 13, and sets a time in a timer 7 to obtain a timing for energizing the thermal head 13.

FIG. 7 is a diagram illustrating the space motor excitation timing and the thermal/nod energization timing.

For example, when the timer 6 is set to 5 ms, the timer 6 starts up every 5 seconds and falls off after a negligible amount of time. When the timer 6 rises, an interrupt is applied to the processor 4, and the processor 4 uses this interrupt to control the output port 5 to switch the drive signals of the terminals (a) to (d) in FIG.

Usually, a 4-phase pulse motor is used with 2-phase excitation and 1-phase stop. For example, if the A phase is stopped, a starting lock current of 20 m5 is first applied to the A phase, and then 5 m5 is applied to the A and B phases.
A magnetic excitation current is supplied, the excitation current of the A phase is stopped, and a 5m5JIJ magnetic current is supplied to the B and C phases. In this way, AB phase, BC phase, CD phase, DA phase, AB phase and so on, 5
It rotates by supplying an exciting current every ms.

If the exciting current is supplied to the BC phase and then stopped at the C phase, an additional 20m5 stop lock current is supplied only to the C phase to stop the pulse motor.

For example, when switching from the BC phase to the CD phase as shown in the excitation phase in FIG. 7, the processor 4 switches the excitation phase as shown by the arrow at the rise of the timer 6. At the same time, the output boat 5 is controlled so as to send a drive signal for energizing the head to the required terminal among the terminals a''-x shown in FIG.

Further, the timer 7 is set to 1 ms, for example, and activated.

Timer 7 falls when activated and rises after 1 m has elapsed. At this rising edge, an interrupt is generated to the processor 4. When an interrupt is generated by the timer 7, the processor 4 stops energizing the thermal head 13. Since the excitation phase of the space motor 15 is switched for each dot, the thermal head 13 is heated by one threshold for each dot.

The timing at which the heads H1 to H24 of the thermal head I3 are heated, the ink on the thermal transfer ribbon melts, and dots are transferred to the printing paper is at the position shown in FIG. 7, immediately before the head energization time is stopped.

FIG. 8 is a diagram illustrating the printing state.

In this figure, the position where the space mechanism including the thermal head 13 moves when the space motor 15 is driven is shown on the vertical axis, and the excitation switching order of each excitation phase of the space motor 15 is shown on the horizontal axis.

As described above, the thermal head 13 is at the position A in the A phase in which the starting lock current flows.

When the AB phase is excited, the thermal head 13 starts moving to the AB position rotated by a half pitch of the space motor 15 as shown by a curve 19. Next, when the BC phase is excited, pin 1 of the space motor 15 is activated.

Move to the BC position rotated by 1.

As shown in song *19, even if the excitation phase of the space motor 15 is switched, the thermal head 13 cannot immediately move to the target position and is delayed. However, as explained with reference to FIG. 7, the dots are transferred at the position shown in FIG. 8.

[Problem that the invention seeks to solve]

As described above, since the thermal head is energized before it reaches a predetermined position, the dots will be misaligned when printing starts or ends.

FIG. 9 is a diagram illustrating the state of printed dots.

As is clear from FIG. 8, the first dot 1-20 is printed at the position of the space motor A, and the next dot 22 is printed at the position AB, which is advanced by half a pitch. is printed. But the next dot 23
．． 24 is printed at the position of BC and CD, which are each advanced by one pitch, so the interval between them is normal.

Therefore, there is a problem that the quality of printed characters deteriorates.

[Means for solving problems]

The above problem is that in serial or line-type dot printers that use a pulse motor to feed the print head or feed the printing paper, the printing mechanism or printing paper feeding mechanism reaches its normal position from the time the drive current is switched to rotate the pulse motor. In the case where a time generating means is provided to generate the time until printing is performed without run-up or overrun, this problem can be solved by supplying the drive current to the print head after the time generated by the time generating means has elapsed.

[Effect]

In other words, the pulse motor excitation phase switching period minus the print head energization time or a shorter time is generated.
Based on this generation time, the print head is energized when as long as possible has elapsed from the excitation phase switching point.

〔Example〕

FIG. 1 is a block diagram of a circuit showing an embodiment of the present invention.
FIG. 2 is a diagram explaining the timing of the present invention.

In FIG. 1, the specifications of the timer 7 in the circuit shown in FIG. 4 are changed to a timer 20. The timer 6 is set to 5 ms by the processor 4 as in FIG. When switching from the BC sum to the CD phase as shown in the excitation phase, the processor 4 switches the excitation phase as shown by the arrow at the rise of the timer 6. Then, the timer 20 is set to Nma and activated.

When the timer 20 is started, it falls down, starts up after Nm has elapsed, and falls down after a negligible amount of time has elapsed.

Then, when the lea has passed, it will stand up again.

When the timer 20 rises after Ntls has elapsed, an interrupt is generated to the processor 4, and the processor 4 interrupts the thermal head 1.
3. Start energizing. The processor 4 then uses the thermal head 13 by an interrupt caused by the rise after l- has elapsed.
energization is stopped.

In this case, Nm≦5am-1ma, and in this example, 3
Good results were obtained at ~3.5+is.

The timing at which each of the thermal heads 7 and 13 is heated, the ink on the thermal transfer ribbon melts, and the dots are transferred to the printing paper is at the position shown in Figure 2, which is immediately before the head energization time stops. .

FIG. 3 is a diagram illustrating a printing state according to the present invention.

The vertical axis indicates the position to which the space mechanism including the thermal head I3 moves when the space motor 15 is driven, and the horizontal axis indicates the excitation switching order of each excitation phase of the space motor 15. As mentioned above, in the A phase where the startup lock current flows, the thermal head 1
3 is in position A.

When the AB phase is excited, the thermal head 13 starts moving to the AB position where the space motor 15 has rotated by a half-pinch, as shown by a curve 19. Next, when the BC phase is excited, it moves to the BC position rotated by l pitch of the space motor 15.

As shown by a curve 19, when the excitation phase of the space motor 15 is switched, the thermal head 13 travels slightly past the target position and then stops at the normal position. Here, as explained with reference to FIG. 2, the dots are transferred at the positions shown in FIG. 3. Therefore, the first dot is printed at position AB, and the next dot is printed at position BC, which is advanced by one pitch.

In the embodiment, a case where the speed of the space motor 15 is constant has been described, but it is also applicable to a case where printing is performed while accelerating and decelerating. The same applies to paper feeding in line type printers.

(Effects of the Invention) As explained above, according to the present invention, the intervals between the dots forming the printed characters are maintained correctly, so that the printing quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit showing an embodiment of the present invention, FIG. 2 is a diagram explaining the timing of the present invention, FIG. 3 is a diagram explaining the blank state according to the present invention, and FIG. 4 is a thermal transfer printer. A block diagram of a circuit showing an example; FIG. 5 is a diagram showing an example of a detailed circuit of the thermal head 13 and the driver 8; FIG. 6 is a diagram showing an example of a detailed circuit of the space motor 15 and the driver 10; The figures are diagrams for explaining the space motor excitation timing and the thermal head energization timing, FIG. 8 is a diagram for explaining the printing state, and FIG. 9 is a diagram for explaining the state of the printed dots. In the figure, 1 is an input/output port, and 2 is a ROM. 3 is RAM, 4 is processor, 5 is output port, 6.7.20 is timer, 8 to 11 is driver, 12 is input port, 13 is thermal head, 1
4 is a magnet, 15 is a space motor, 16 is a line feed motor, 17 is a switch, and 18 is a sensor. Figure 3 Figure 5 Figure Δ

Claims (1)

[Claims] In a serial dot printer that uses a pulse motor to feed the print head or a line type dot printer that feeds printing paper, the time from the time when the drive current that rotates the pulse motor is switched until the printing mechanism or printing paper feeding mechanism reaches the normal position. A printing method for a dot printer, characterized in that when a time generating means is provided and printing is performed without run-up or overrun, a drive current is supplied to the print head after the time generated by the time generating means has elapsed.