JP2001225493A - Dot impact printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a dot impact printer by a simple circuit constitution and low manufacturing costs. SOLUTION: A printing head has 12 pairs of needle pins each pair having leading ends disposed to positions where the leading ends are nearly point symmetric to the same one point. A printing head control circuit for controlling the printing head has one or two pairs of delay circuits 21 and 21 for every pair of the needle pins to output input signals with a predetermined time delay. Two printing data respectively driving one pair of needle pins are selectively inputted by a switcher 22 respectively to two pairs of the delay circuits 21 and 21, or one of the data is selectively inputted to one pair of the delay circuits 21. An output destination for the printing data after being inputted to one or two pairs of the delay circuits 21 and for the printing data not inputted to the delay circuits 21 is switched by a switcher 23. The switchers 22 and 23 are switched depending on whether printing is executed in a forward line direction or a rearward line direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dot impact printer.

[0002]

2. Description of the Related Art A dot impact printer has a print head control circuit for controlling a print head having a plurality of needle pins for printing. The print head control circuit is provided with a delay circuit corresponding to each needle pin of the print head. Print data for driving a needle pin corresponding to each delay circuit is input to each of the delay circuits, and the print data is output with a predetermined time delay to a driver for driving a print head. The delay time of each delay circuit differs for each needle pin, and the drive timing between the needle pins is set by the different delay time for each needle pin.

[0003]

However, in the case of a dot impact printer in which printing can be performed in both the forward and reverse directions in the line direction, a delay circuit is not provided in the forward and reverse directions of the line direction. For the needle pins with different delay times, two delay circuits must be provided for one needle pin for the positive direction and the opposite direction in the line direction, respectively, which complicates the circuit configuration, and There is a problem that the manufacturing cost increases due to an increase in the number of elements.

An object of the present invention is to realize a dot impact printer capable of performing printing in both the forward and reverse directions of the line direction with a simple circuit configuration and low manufacturing cost.

[0005]

According to a first aspect of the present invention, a print head is controlled by a print head control circuit based on print data, and printing in a dot impact system is performed in a line direction by moving a carrier. In a dot impact printer that can be operated in both forward and reverse directions, the print head has a plurality of pairs of needle pins each having a tip located at a position substantially point-symmetric with respect to the same point. The print head control circuit includes one or two sets of delay circuits for outputting an input signal with a predetermined time delay for each of the pair of needle pins, and drives each of the pair of needle pins. The two print data have different drive timings, and both of the two sets of delay data correspond to the pair of needle pins. A first switching circuit for selectively inputting the signals to the path one by one, or selectively inputting one of the signals to the pair of delay circuits corresponding to the pair of needle pins; A second switching circuit for switching the output destination of the print data after being input to the two sets of delay circuits and the print data not input to the delay circuits; Switching is performed by the first and second switching circuits depending on which direction is to be performed, thereby providing switching means for setting a drive timing between the needle pins with the time delay by each of the delay circuits. This is a dot impact printer.

Therefore, a pair of needle pins arranged at positions substantially symmetrical with respect to the same point,
If the delay time of the delay circuit has the opposite relationship depending on whether the printing is performed in the forward or reverse direction of the line direction, two or one delay circuit is shared by two needle pins, and printing is performed. It is possible to switch the delay circuit used by each of the two needle pins depending on whether the direction is reversed in the line direction, so the number of delay circuits used can be reduced, and a simple circuit configuration and low manufacturing cost can be achieved. Can be realized.

[0007]

FIG. 1 is a block diagram showing an electrical connection of an impact dot printer 1 according to an embodiment of the present invention. As shown in FIG. 1, the impact dot printer 1 has a CPU for centrally controlling each unit.
ROM 3 storing various control programs and the like
And a RAM 4, which stores various data in a rewritable manner and serves as a work area of the ROM 3, is connected by a bus 5.

The bus 5 has an impact dot printer 1
An external I / F 6 serving as an interface for connecting the device to an external device, and an ASIC (Ap
Replication Specified IC) 7 is connected.

The ASIC 7 includes a print head control circuit 10 that controls a driver 9 that drives a print head 8 that performs printing in a dot impact system based on print data input from an external device via an external I / F 6. Has been implemented. A signal output from the print head control circuit 10 is shaped by a waveform shaping circuit 11 mounted on the ASIC 7 and output to the driver 9. The ASIC 7 is also provided with a carrier motor control circuit 14 that controls a driver 13 that drives the carrier motor 12. The carrier motor 12 serves as a drive source for driving a carrier (not shown) that moves the print head 8 in the line direction. The ASIC 7 also has an LF motor control circuit 17 that controls a driver 16 that drives the LF motor 15. The LF motor 15 is a drive source for performing line feed.

FIG. 2 shows the needle pin 1 in the print head 8.
It is a top view which shows arrangement | positioning of the front-end | tip part of No. 8. The print head 8 has, for example, 24 pins. And 24
Are composed of twelve pairs of needle pins 18, 18 each having a distal end located at a position substantially symmetrical with respect to the same point 19. That is, pin 1 and pin 24, pin 2 and pin 23,
Pins 3 and 22 are approximately point-symmetric with respect to point 19, respectively. Further, the intervals between the needle pins 18 are set equally.

FIG. 3 is a block diagram showing a specific circuit configuration of the print head control circuit 10. As shown in FIG. As shown in FIG. 3, one delay circuit 21 is provided for each of the 1 and 24 pins that are point-symmetric with respect to the point 19. Print data for driving one pin is input to the delay circuit 21 corresponding to one pin, and print data for driving the 24 pin is input to the delay circuit 21 corresponding to 24 pins. The print data input to each delay circuit 21 is output with a predetermined time delay.

Another pair of needle pins 18, 18, which are substantially point-symmetric with respect to point 19,
For the 3rd pin, the 3rd pin and the 22nd pin,..., The 11th pin and the 14th pin, two sets of delay circuits 21 and 21 are prepared corresponding to the pair of needle pins 18 and 18, respectively. A switcher 22, which is a first selection circuit, is connected to the input side of the two sets of delay circuits 21, 21 corresponding to the pair of needle pins 18, 18, and a switcher, which is a second selection circuit, to the output side. 23 are connected. The switcher 22 receives two print data for driving the pair of needle pins 18 and 18 from the input terminals A and B, respectively, and selectively outputs the two print data from one of the output terminals Q and R. Output to

For example, in the case of pins 3 and 22, in switcher 22, print data corresponding to pin 3 is input to input terminal A, and print data corresponding to pin 22 is input to input terminal B. Print data and 2
One of the print data corresponding to the two pins is selectively output from the output terminal Q to one delay circuit 21, and the other print data is output from the output terminal R to the other delay circuit 21.
Is output to In the switcher 23, the print data output from one of the delay circuits 21 is input to an input terminal A, and the print data output from the other delay circuit 21 is input to an input terminal B, and corresponds to pin 3. The output print data is selectively output from the output terminal Q.
The print data corresponding to the pin is selectively output from the output terminal R.

For pins 12 and 13 which are substantially point-symmetric with respect to point 19, the pair of needle pins 18 and
A single delay circuit 21 is provided corresponding to. Switchers 22 and 23 are also provided. The switcher 22 selectively inputs one of print data for driving the 12-pin and print data for driving the 13-pin to the delay circuit 21 and inputs the other print data to the delay circuit 21. Output without The switcher 23 selectively outputs, from the output terminal Q, print data for driving the 12-pin out of the print data output from the delay circuit 21 and the print data output from the switcher 22 without being input to the delay circuit 21. And 1
Print data for driving the three pins is output from the output terminal R.

Each of the delay circuits 21 constituting the print head control circuit 10 is composed of a single D flip-flop 24 or a plurality of D flip-flops 24,
24,... Are constituted by shift registers connected in series. A predetermined clock signal is input to each of the D flip-flops 24, 24,. The 1-bit print data held by each of the D flip-flops 24, 24,... Shifts the D flip-flop 24 by one at the timing of inputting the clock signal. D flip-flop 2
, 24,... Depends on the pin numbers of the corresponding pair of needle pins 18, 18, respectively. In each of the delay circuits 21, the delay time from when the print data is input to when the print data is output is “the period of the clock signal × the number of D flip-flops 24”.

It should be noted that other specific structures such as a specific mechanism and structure of the impact dot printer 1 are well known, and therefore, detailed description thereof will be omitted.

The above-described impact dot printer 1
Can be executed from both the forward and reverse directions in the line direction. When printing is performed, the CPU 2 determines whether printing is to be performed in the forward or reverse direction of the line direction, and switches the switchers 22 and 23 with a print direction selector signal. , 18,... Are driven. This implements switching means.

That is, for pins 3 to 23,
The required delay time differs between the pair of needle pins 18 and 18 arranged at positions substantially symmetrical with respect to the point 19 depending on whether the printing is performed in the forward or reverse direction of the line direction. Is reversed between the pair of needle pins 18 depending on whether the printing is performed in the forward or reverse direction of the line direction. For example, if pins 3 and 22 are to be printed in the positive direction, if pin 3 is a delay time for five D flip-flops 24, then
The pin has a delay time corresponding to seven D flip-flops 24. If this prints in the negative direction, pin 3 is D
If the delay time is equivalent to seven flip-flops 24, the delay time of pin 22 is equivalent to five D flip-flops 24, which is the reverse of the case where printing is performed in the positive direction. In FIG.
For each of the cases where printing is performed in the positive direction (→) and the reverse direction (←) in the line direction, the number of times print data is held at each pin (how many clock signals print data is held) is shown. .

As described above, depending on whether the printing is performed in the forward or reverse direction of the line direction, the two needle pins 18 and 18 use two or one of the two needle pins 18 when the delay time of the delay circuit 21 is reversed. The two delay circuits 21 are shared. The two needle pins 1 depend on whether the printing is performed in the forward or reverse direction of the line direction.
The delay circuits 21 used by the switches 8 and 18 can be switched by switchers 22 and 23, respectively.

FIGS. 4 and 5 are block diagrams showing other circuit examples of the print head control circuit 10 as a comparative example of the circuit of FIG. 4 and 5 differ from the circuit of FIG. 3 in the following points. That is, the circuits corresponding to pins 1 and 24 are the same as the circuits in FIGS. 4 and 5 for the circuit in FIG. 3 but the circuits corresponding to pins 2 to 23 are different.
In the circuit of FIG. 3, two delay circuits 21 and 21 having different delay times are provided for a pair of needle pins 18 and 18 arranged at positions substantially symmetric with respect to a point 19.
4 and 5, one or two delay circuits 21 and 21 are prepared for each needle pin 18, and print data for each needle pin 18 is stored in two delay circuits 21 and 21. Input together (12 pins,
For 13 pins, one delay circuit 2 for each pin
1 is provided. ). The delay circuit 21 performs printing in the positive direction of the line direction for each needle pin 18, and the delay circuit 21 performs printing in the opposite direction.
Is prepared. The selector 25 determines whether printing is performed in the forward or reverse direction of the line direction.
Selectively output the output of one of the delay circuits 21.

Compared with the circuits of FIGS. 4 and 5, the circuit of FIG.
Since the number of delay circuits 21 corresponding to pins can be reduced by half, the impact dot printer 1 having a simple circuit configuration and low manufacturing cost can be realized.

[0022]

According to the first aspect of the present invention, a pair of needle pins arranged at positions substantially symmetrical with respect to the same one point is used to determine whether printing is performed in the forward or reverse direction of the line direction. If the delay time of the delay circuit is inversely related, use two needle pins for two or one.
It is possible to switch the delay circuit used by each of the two needle pins according to whether the printing is performed in the forward or reverse direction of the line direction by sharing the two delay circuits. Thus, a simple circuit configuration and a low manufacturing cost can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical connection of an impact dot printer according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement of tip portions of needle pins of a print head used in the impact dot printer.

FIG. 3 is a block diagram showing a circuit configuration of a print head control circuit used in the impact dot printer.

FIG. 4 is a block diagram showing a circuit configuration of a print head control circuit which is a comparative example of the print head control circuit.

FIG. 5 is a block diagram showing a circuit configuration of a print head control circuit which is a comparative example of the print head control circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impact dot printer 8 Print head 10 Print head control circuit 18 Needle pin 19 points 21 Delay circuit 22 First switching circuit 23 Second switching circuit

Claims (1)

[Claims] A print head is controlled by a print head control circuit based on print data, and printing in a dot impact method can be performed in both the forward and reverse directions in the line direction by moving a carrier. In the printer, the print head includes a plurality of sets of a pair of needle pins each having a distal end located at a position substantially point-symmetric with respect to the same point, and the print head control circuit includes an input signal. Is provided for each of the pair of needle pins, and the drive timings of the two print data for driving each of the pair of needle pins are different, and Both are selectively input one by one to the two sets of delay circuits corresponding to the pair of needle pins, or A first switching circuit for selectively switching one of the delay circuits corresponding to the pair of needle pins to the one set, and the print data after the input to the one or two sets of the delay circuits And a second switching circuit for switching an output destination of the print data that has not been input to the delay circuit, wherein the first and the second are performed depending on whether the printing is performed in the forward or reverse direction of the line direction. A dot impact printer comprising switching means for switching between the needle pins with the time delay by each of the delay circuits by performing switching by a second switching circuit.