JPH0123813Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a dot printing device having a printing dot hammer.

The present invention is applied to a dot printing device, and herein, a shuttle dot matrix type dot printing device (hereinafter referred to as printing device) will be explained as an example. The shuttle dot matrix method is a method in which printing is performed by reciprocating a printing hammer group having a plurality of printing hammers in the width direction, that is, the row direction, of the printing paper.

The printing device receives characters to be printed as character codes from the host device. According to the received code, the character dot matrix is read from the built-in character generator, and printing dot information is given to each printing hammer. Each printing hammer is excited according to the above-mentioned dot information and prints one dot at a time.

For example, when printing a single Kanji character measuring 24 vertically by 24 horizontally, the character is printed by energizing the printing hammer several dozen to several hundred times.

As can be seen from the above example, the number of times the print hammer is energized varies depending on the type of character. Among these, the case where the number of excitations is particularly large, that is, the case where the printing dot density per printing hammer is high will be described below.

When printing characters with high printing density, it is necessary to take into account the heat generation of the hammer coil, the heat generation of the hammer driver's transistors, diodes, etc., the capacity of the excitation power source, and add some printing restrictions.

Normally, printing is restricted by printing separately on even-numbered and odd-numbered printing hammers, or 1.
There is a method of prohibiting printing for a certain period of time after a line has been printed.

As a means of determining whether the printing dot density is high or low,
A method is used to count the number of dots per line printed just before printing. This method counts the number of dots per line printed by each printing hammer, compares the number with a certain reference value, and imposes printing restrictions if the number is greater than the reference value.

In this method, since the number of dots is counted dot by dot, the number of bits of the counter increases and the number of elements used increases. Furthermore, since the number of dots is huge,
A considerable amount of time is required for counting, and there is a possibility that the printing speed may be reduced.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to reduce the cost of printing devices and increase the printing speed by quickly determining the print dot density using fewer elements and limiting the printing speed. The goal is to prevent the decline.

The present invention provides a printing dot number storage means for storing the number of printing dots corresponding to the printing code, adds this number of dots, and compares it with a reference value, thereby printing with fewer elements and fewer calculations than conventional methods. This method was devised so that the dot density could be determined.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

From the host device 1 to the printing code storage circuit 2 of the printing device
The printed code is transferred to The printing device starts a printing operation when a printing instruction decoder (not shown) receives a printing instruction from the host device 1.

Before starting the printing operation, the number of printed dots is counted for each printing hammer. If the counting result exceeds the reference value, the output of the flip-flop 8 becomes a logical value 1, and some printing restriction is applied.
This operation will be explained in detail below.

First, a reset signal k is output, and the address counter 4 and flip-flop 8 are reset.
As a result, the first print code is output to the data line a, and the address of the dot number storage circuit 3 is accessed. In the dot number storage circuit 3, the number of printed dots corresponding to each printed code is stored at the accessed address. This information is output on data line b. Next, the addition circuit 5 takes in the first number of printed dots from the data line b according to the timing of the addition input signal f, and adds it to the current number of printed dots. However, in the case of the first time, since there is no previous data, the value taken in remains as the result of the addition. The output of the adder circuit 5 is applied to one input terminal _in1 of the comparator circuit 6 via a data line c. The comparison circuit 6 compares the input data of in ₁ with the reference value of the input data of in ₂ output from the overall control section 9, and outputs the result as a comparison output signal i. Since the comparison permission signal h has a logic value of 0, the NAND gate 7 prohibits the signal from being applied to the set input terminal of the flip-flop 8.

The comparison permission signal h is a signal that is output after the addition input signal f is output twice. This assumes that one printing hammer covers a printing range of two characters.

Next, when address clock signal e is output,
Address counter 4 adds 1 to the currently output address and outputs a new address signal. As a result, the print code storage circuit 2 outputs the next print code to the data line a. In the same way as the first operation, the number of printed dots for the second time is output to the data line b, taken into the adder circuit 5 at the timing of the addition input signal f, and added to the previous data. The addition result is output to the data line c, and compared with the reference value data line d by the comparator circuit 6, and the result is output as the comparison output signal i. If the comparison result is smaller than the reference value, it becomes a logical value 0, and if it is larger, it becomes a logical value 1. In the second case, the comparison enable signal h is output, and the comparison output signal i is applied to the set input of the flip-flop 8 via the NAND gate 7. When the comparison output signal i has a logic value of 1, the flip-flop 8 is set and the print limit signal j has a logic value of 1.

Thereafter, the above operation is repeated the same number of times as the number of digits to be printed, and if the number of printed dots in any of the printing hammers exceeds the standard number of printed dots, the output of the flip-flop 8, that is, the printing limit signal j is The logical value becomes 1.

Using the print restriction signal j which is the output of the flip-flop 8, it is possible to judge whether or not the number of print dots in any of the print hammers has exceeded the reference number of dots for starting print restriction.

If the print restriction signal j has a logical value of 1,
Printing restrictions can be applied to the printing device by some method, such as printing using even-numbered and odd-numbered printing hammers, and the printing speed can be reduced. By lowering the printing speed, it is possible to suppress heat generation of the hammer coil.

In the above embodiment, one printing hammer has two
The operation has been explained assuming that it covers a printing range of characters. The present invention is effective no matter how many characters the printing hammer covers. This is possible by simply changing the value of the reference value signal d for the number of printed dots shown in FIG. 1, the timing of the comparison permission signal h, and the addition circuit clear signal g.

Furthermore, although we have described a shuttle matrix type dot printing device as an example of a printing device, it is also possible to use a serial dot printing device in which printing wires are arranged vertically or a multi-head type dot printing device in which a plurality of printing wire heads are arranged horizontally. Applicable.

As explained above, according to the present invention, by providing the print dot number storage circuit, the determination of the print dot density can be realized with a small number of elements, and the cost of the control device is reduced. In addition, the number of calculations required to count the number of dots is reduced from a few tenths to a few hundred times compared to conventional methods, making it possible to determine the high or low density of printed dots in a short time, preventing a drop in printing speed. become able to.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the control device of the present invention, and FIG. 2 is a timing chart for explaining FIG. 1. In the figure, 1 is a host device, 2 is a print code storage circuit, 3 is a dot number storage circuit, 4 is an address counter, 5 is an addition circuit, 6 is a comparison circuit, 7 is a NAND gate, 8 is a flip-flop, and 9 is an overall control unit. It is.

Claims (1)

[Claims for Utility Model Registration] A single printing head in which a plurality of printing wires are arranged side by side in the paper feeding direction, or a multihead in which a plurality of printing heads are arranged in a row direction, or a plurality of printing heads are arranged in a line along the row direction. The dot printing hammer group is moved back and forth along the line direction, and printing is performed in the process of this reciprocation, and the number of printing dots printed by each printing head or each printing hammer when printing one line is counted. In a dot printing device, the count value is compared with a reference value by a comparing means, and when the count value is equal to or higher than the reference value, the printing speed is reduced. A printing dot comprising means for storing the number of printed dots corresponding to a code, and means for reading and adding the number of printed dots of each printing code from the storage means, and printing the addition result of the adding means when printing one line. A control device for a dot printing device characterized by a number of dots.