JPH0441262A - Printing head controller - Google Patents

Abstract

PURPOSE:To correct a slant of a pin string of a print head slanted with respect to the moving direction of a carriage so as to make it possible to reduce the number of gates by providing AND means to AND a print data and an output of an energizing timer. CONSTITUTION:A CPU 1 accesses a character font to be printed from a character font ROM 3 in accordance with a rise timing of a print data interrupt demand signal m having a cycle same as an interval signal (p) sent from a first timer 5, and a print data signal (g) of each of 24 pins is outputted to a latch section 11. The latch section 11 makes an output s of individual timers 8-1-8-24 to be a latch clock so as to latch the print data signal (g) at every pin. Further, an AND circuit 12 ANDs a print data signal (v) of latched each pin of 24 bits and the timing signal s so as to obtain a driving signal (w) of each pin of a head. A head driver 19 gives a pulse voltage to a head coil 10 in accordance with the driving signal (w) so as to drive the head.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a print head control device for a dot matrix printer.

Conventional technology In recent years, dot matrix printers have been using Ti on the carriage to avoid noise caused by each pin hitting the dot at the same time, to avoid rJPi interference when using a large capacity power supply or electromagnetic force, and to achieve high-density packaging. A distributed print head is used that prints by supplying a drive signal corresponding to each pin in a row of print head pins arranged at an angle with respect to the direction perpendicular to the direction of carriage movement. A printhead control device for an integrated printhead is used.

A conventional print head control device will be described below.

FIG. 4(a) shows the pin row pattern of a conventional 24-pin wire dot head. Figure 4(b) shows the pin row pattern of a distributed print head in which the pins are arranged at an angle.
C) is another example of a pin array pattern for a distributed print head.

FIG. 5 is a drive timing chart of the 24-pin wire dot head, and FIG. 5(a), FIG. 5(b), and FIG. 5(c) are respectively FIG. b) corresponds to the head with the pin row pattern in FIG. 4(C). In the pin row pattern of Fig. 4(a), Fig. 5(a)
As shown in a), the timer that generates the timing T7 that determines the spacing between the dots that make up the characters and the timing T8 that determines the energization time of the head coil that drives the pins of the head may be used. In the pin array pattern b), as shown in Figure 5(b), each pin has a different drive timing. A timer is required to generate timing T9 that determines the delay time of , and it is necessary to delay all the drive timings of the 24 pins by timing T9.

In the pin arrangement of FIG. 4(C), the control circuit is simplified by delaying the drive timing for each group of six pins as shown in FIG. 5(C).

FIG. 6 is a block diagram of a conventional print head control device having the pin arrangement shown in FIG. 4(b). In Figure 6, 22
23 is a character font read-only memory (hereinafter abbreviated as character font ROM) in which character font data is written, and 23 is a timing generation unit that generates timing for distributing print data. It is comprised of a timer 24 that generates clocks with timings T7 and T8 as shown, a timer 25 that generates clocks with timing T9, and an oscillator 26 that operates these timers 24 and 25. Reference numeral 27 is a shift register section for delaying print data read out from the character font ROM 22. 28 is a central processing unit (hereinafter referred to as C
It is abbreviated as PU. ) controls each of the character font ROM 22, timing generation section 23, and shift register section 27 via an input/output section (hereinafter abbreviated as 170 section) 29. 30 is 24 AND circuits, each with CP
The print data for 24 pins from U28 and the output of timer 24 are ANDed. 31 is a head driver that applies a pulse signal to the head coil 32.

The operation of the print head control device configured as described above will be described below.

The CPU 28 uses the timer 24 to output the timing signal of the first pin shown in FIG. 5(b) (hereinafter abbreviated as shift data).
The falling timing W of is always notified, and the CPU 28
reads the print data for 24 pins from the character font ROM 22 and sends it to the AND circuit 30 according to the falling timing of the shift data, and the AND circuit 30 ANDs each of the print data for the 24 pins and the output of the timer 24.
and sends it to the shift register section 27. Further, the timer 25 receives character mode data X from the CPU 28 and outputs a clock t (hereinafter abbreviated as shift clock) having a timing having a period of T9 in FIG. 5(b) according to the printing mode. It is sent to the shift register section 27. The shift register section 27 generates drive signals from pins 1 to 24 in FIG. 5(b) based on the output from the AND circuit 30 (No. 3, shift clock t) and sends them to the head driver 31. , the head is driven by applying a pulse voltage to the head coil 32 in response to a drive signal from the shift register section 27.

The frequency of shift clock t changes depending on the printing mode for various characters, but in order to maintain the timing of T8, T8 must be an integer multiple of shift clock t, so the frequency of shift clock t inevitably changes. It becomes necessary to increase the frequency, that is, to supply the shift clock t obtained by subdividing the T9 period to the shift register section 27. For this reason, a plurality of stages of shift registers in the shift register section 27 were provided.

Problems to be Solved by the Invention However, in the conventional configuration, the character font ROM
The data of the energization time of the head coil 32 is added to the print data read from the print data 22, and the data of the energization time is added to the print data.
7) to generate distributed data corresponding to each pin in the pin row of the distributed print head, so the energization time of the head coil 32 is constantly shifted in order to maintain the energization time of the head coil 32 for all printing modes. It is necessary to increase the frequency of the shift clock so that it is an integral multiple of the cycle of the shift clock that drives the register section 27, and the shift register section 32 has a large number of shift registers and a large number of gates. Figure 5 (C) to reduce the number of gates.
If the pin row pattern is configured as shown in FIG.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention includes a first timer that generates a timing signal whose cycle is the printing interval, a shift register that shifts the timing signal, and an output of the shift register. The present invention includes an energization timer for maintaining the energization time of the print head, a print data output means for outputting print data, and an AND means for logically multiplying the print data and the output of the energization timer.

Effect of the Invention With the above-described configuration, the present invention can maintain the energization time of the print head without increasing the frequency of the shift clock, and can correct the inclination of the pin row of the print head that is inclined with respect to the moving direction of the carriage. .

Embodiment FIG. 1 is a block diagram of a print head control device in an embodiment of the present invention. In FIG. 1, 1 is a central processing unit (hereinafter abbreviated as CPU), 2 is an input/output unit (hereinafter abbreviated as I10 unit) that has an interface between each device, and 3 is a character font read-only memory ( (hereinafter abbreviated as character font ROM).

4 is an oscillator, and 5 is a first timer which is driven by the basic clock C generated by the oscillator 4 and outputs a print data request interrupt signal d and a signal p having a period of print interval time t1. 6 is a second timer which inputs print mode data e from the CPU 1 for switching character quality and basic clock C generated by the oscillator 4, and is a drive signal for each adjacent pin that corrects the slope of the pin row according to each print mode. A clock signal f having a period equal to the time difference of is output. Reference numeral 7 denotes a shift register section which uses the clock signal f as a shift clock to shift the signal p having a cycle of the print interval time t1 sent from the first timer and generates a timing signal for each pin. Numerals 8-1 to 8-24 are individual timers which receive timing signals r generated by the shift register section 7 for pins 1 to 24 and provide the head energization time for each pin. Reference numeral 11 denotes a latch section which uses the print data signal g sent from the CPU 1 through the lotus line as input data and uses the output signals S of the individual timers 8-1 to 8-24 as a latch clock. 12 is an individual timer 8-1 to 8
A between the output signal S of -24 and the output signal ■ of the latch section 11
This is an AND circuit that takes an ND and outputs a drive signal W. 9
applies a pulse voltage to the head coil 10 using output signals i-1 to j-24 from the head driver to drive the head.

FIG. 2 is a pattern of pin rows of a head controlled by a print head control device in an embodiment of the present invention. In Figure 2, the pin row pattern of the head is such that among the 24 pins, the odd numbered pins are in the first row and the even numbered pins are in the second row. Of these, pin N and pin (N+2) are 1/120*1/
It is shifted by 12 inches in the printing line direction. Here 1/1
20 inches is the dot spacing between characters. Furthermore, pin N and pin (N+ 1) are set to 1/120*1/1 so that the pins in the first and second rows are not driven at the same time.
The intervals are different in length from an integral multiple of 2 inches. That is, the 24 pins of the print head are distributed at 24 timings to perform printing during the distance that the print head moves by 1/120 inch so that each pin is not turned on at the same time.

The operation of the print head control device configured as described above will be explained below.

FIG. 3 is a timing chart of the print head control device of FIG. 1. The first timer 5 is the print interval time t
The period of 1 is outputted to the register section 7 as an interval signal p. In the shift register section 7, the second
Correcting the inclination of the pin row output from the timer 6 of
Using a signal f having a period equal to the time difference t3 between the drive signals of adjacent pins as a shift clock, the interval signal p is delayed by t3 for each pin and outputs r1 to r24. for example,
When the CPU 1 sets t3 to 36 in the second timer using the signal e, the second timer sets t3 to 36 in the shift register section 7.
A signal f with a period of is sent. Individual timers 8-1 to 8-2
4, a high level binding timing signal S1 to s24 is generated during a preset head energization time t2 at the rising edge of r1 to r24.

The CPU calls the font of the character to be printed from the character font ROλ (3) according to the rising timing of the print data interrupt request signal m, which has the same cycle as the interval signal p sent from the first timer 5, and sets the font for each of the 24 pins. The print data signal g of 24 bits is output to the latch section 11.The latch section 11 uses the output S of the individual timers 8-1 to 8-24 as a latch clock and latches the print data signal g for each pin. Marking of each latched pin, character data signal V, timing signal, and AN of S
By calculating D with an AND circuit 12, a drive signal W for each pin of the head is obtained. The head driver 9 receives this drive signal W.
Accordingly, the head is driven by applying a pulse voltage to the head coil 10.

In this embodiment, by using an individual timer, the number of gates can be reduced to about ⅓ compared to the conventional circuit.

Note that this embodiment can also be used in the case of single mode printing.

Effects of the Invention As described above, the present invention includes a first timer that generates a timing signal whose period is a printing interval, a shift register that shifts the timing signal, and an output of the shift register that holds the output of the print head for the energization time of the print head. Energization timer,
By providing a print data output means for outputting print data and an AND means for logically multiplying the print data and the output of the energization timer, the energization time of the print head can be maintained without increasing the frequency of the shift clock. , it is possible to correct the inclination of the pin array of the print head that is inclined with respect to the moving direction of the carriage, and it is possible to reduce the number of cages.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a print head control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a pin row pattern of a head controlled by the print head control device according to an embodiment of the present invention. FIG. 3 is a timing diagram of a print head control device according to an embodiment of the present invention, which is a block diagram of a conventional print head control device. 1 ・ 2 ・ 3 ・ 4 ・ 5 ・ 6 ・ 7 ・ 8 ・ 9 ・ 10 ・ 11 ・ 12 ・ CPU 170 copies Character font ROM Oscillator 1st timer 2nd timer Shift register section Individual timer head driver head coil latch section AND circuit

Claims (1)

[Claims] A print head control device that is mounted on a carriage and performs printing by supplying drive signals corresponding to each pin of a pin row of the print head that is inclined with respect to a direction perpendicular to the moving direction of the carriage, A first timer that generates a first timing signal whose cycle is a printing interval; and a second timing signal whose cycle is a time difference between drive signals for each adjacent pin that corrects the inclination of the pin row. a second timer, a shift register that uses the second timing signal as a shift clock and shifts the timing signal, an energization timer that holds the output of the shift register for the energization time of the print head, and a printer that outputs print data. A print head control comprising: a data output means; an AND means for logically multiplying the print data and the output of the energization timer; and a drive means for driving the head by the output of the AND means. Device.