JPH1128838A - Dot printing data holding circuit for dot line printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the no. of circuits of a shift resistor for storing dot printing data by providing a circuit which switches addresses of a storage element for holding the dot printing data at a full dot position and a half dot position. SOLUTION: When an HF LOAD-P signal in an address switching circuit 1 is HIGH, an address at a half dot position is transmitted to an A input of a comparator 2. Then, the comparator 2 makes an output terminal effective when the address of a full dot position or the half dot position coincides with a data transferring timing signal. Then, when a main signal is made effective, dot printing data are synchronized with a CLK signal and are successively stored into a shift resistor 3. Then, a printing data switching circuit 4 outputs a driver signal for driving a printing hammer at the half dot position and a hammer driving signal when an AND condition for the dot printing data is formed to drive the printing hammer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot line printer capable of printing at a density position (hereinafter, referred to as a half dot position) twice as large as a standard printing density position (hereinafter, referred to as a full dot position). And
More specifically, the present invention relates to a dot print data holding circuit.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a hammer pin configuration of a dot line printer. The hammer pins 10 in this example are arranged in 12 columns in the row direction and at a substantially constant interval P in the column direction, and each hammer pin 10 covers the range from the same column to the adjacent print pin. The printing timing of these hammer pins 10 is shifted for the purpose of magnetic interference and averaging of power consumption, and the printing timing is as shown in FIG. Specifically, the first row of the hammer pins corresponds to the drive signal (1), the sixth row of the hammer pins corresponds to the drive signal (2), and so on. Row 7, Row 7, Row 12, Row 5, 10
The third row, the eighth row, and the like are provided, and a printing group corresponding to each row of the hammer pins is provided.

Next, the full dot position and the half dot position will be described. The full dot position is a position that represents a reference print density interval. If the reference print density is 1/180 inch, printing at positions spaced by 1/180 inch as shown in FIG. 6 is the full dot position. When printing at 120 DPI (dots / inch) intervals where the printing density is smaller than the reference printing density interval, as shown in FIG. 6, 1/2 intervals of 1/180 inch (1/360 inch) as shown in FIG. Need to be printed. That is, when the reference print density is 1/180 inch interval, the middle position is the half dot position.

Next, a description will be given of a dot print data holding circuit capable of printing at such a half dot position. FIG. 3 is a block diagram of a dot print data holding circuit for one of a plurality of print groups. Reference numeral 2 denotes a comparator, reference numeral 3 denotes a shift register, and reference numeral 4 denotes a print data switching circuit for a full dot position and a half dot position. .

The input of the comparator 2 receives the fixed address and the data transfer timing signal given to the shift register, and makes the output signal of the comparator 2 valid when the input signals match each other. This signal is CLKENB (clock enable) of the shift register 3.
Since this signal is valid, it is connected to the terminal
The LK signal becomes valid, and print data is sequentially stored in the shift register 3 in synchronization with the CLK signal. The shift register 3 is divided into a full dot position and a half dot position, and each dot print data is stored separately. The print data switching circuit 4 turns on the hammer drive signal when the AND condition between the dot print data stored in the shift registers for the full dot position and the half dot position and the print hammer drive signal is satisfied. When the hammer drive signal is turned on, a drive element (not shown) is turned on, and a current flows through a hammer coil (not shown).

As described above, when printing is performed at 120 DPI intervals, a storage element for holding dot print data at both the full dot position and the half dot position is required. Further, since the dot print data holding circuit described above is for a certain one of a plurality of print groups, the number of print data holding circuits increases in proportion to the number of print hammers arranged in the row direction.

[0007]

In the conventional dot print data holding circuit, when printing at intervals of 120 DPI,
Since it is necessary to hold the dot print data at both the full dot position and the half dot position, the number of circuits of the dot print data storage shift register is doubled, which hinders circuit downsizing.

It is an object of the present invention to provide an inexpensive dot print data holding circuit having a small circuit scale even when printing is performed at a half dot position.

[0009]

In order to achieve the above object, in a dot print data holding circuit according to the present invention, a circuit for switching an address of a storage element holding dot print data between a full dot position and a half dot position. Can be solved by using a storage element that stores print data at the full dot position and a storage element that stores print data at the half dot position in common.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram of a dot print data holding circuit showing one embodiment of the present invention. 1 is an address switching circuit, 2 is a comparator, 3 is a shift register, 4
Is a print data switching circuit for the full dot position and the half dot position. The same circuits as those in the prior art are denoted by the same reference numerals. The address switching circuit 1 is composed of a selector 5, and inputs are given addresses of a full dot position and a half dot position, respectively. The address of the full dot position or half dot position is switched according to the polarity of the HF LOAD-P signal, and the corresponding address is output from the output terminal. Specifically, when the HF LOAD-P signal is HIGH, the address of the half dot position is transmitted to the A input of the comparator 2. The comparator 2 validates the output terminal when the address of the full dot position or the half dot position matches the data transfer timing signal. When this signal becomes valid, dot print data is sequentially stored in the shift register 3 in synchronization with the CLK signal. The print data switching circuit 4 outputs a drive signal for driving a print hammer at a full dot position or a half dot position, and a hammer drive signal when an AND condition of dot print data is satisfied. Drive the printing hammer.

FIG. 2 is a printing timing chart when the dot print data holding circuit according to the present invention is applied.
It will be explained in. After printing of the full dot position is completed at the timing of D, the HF LOAD-P signal is
At this timing, the dot print data for the half dot position to be printed next is transferred to the shift register, and the half dot position is printed at the timing E. Similarly, after the printing of the half dot position is completed at the timing E, the dot print data for the full dot position is transferred to the shift register at the timing C at which the HF LOAD-P signal is LOW. Thus, between printing at the full dot position and printing at the half dot position,
What is necessary is just to transfer the dot print data of the dot position to be printed next. In the description, it is described that the half dot position is continuously printed after the full dot position. However, actually, the printing is not performed continuously due to the operation cycle of the printing hammer. Generally, the shortest operation cycle of the print hammer is set to a value at which the reference dot position can be continuously printed. Therefore, when the reference dot position is at an interval of 1/180 inch,
The shortest cycle at which the half dot position can be printed next to the full dot position is the interval of 1/120 inch shown in FIG. Therefore, for the half dot position that cannot be printed due to the operation cycle of the print hammer,
The print data of the polarity in which the print hammer does not operate will be transferred.

By adopting the above circuit system, the shift register for the full dot position and the shift register for the half dot position can be made common, and the dot print data holding circuit can be reduced to about 1/2 or less. Becomes Further, since the print data switching circuit 4 does not need to switch between the dot print data at the full dot position and the dot print data at the half dot position as in the prior art, the circuit contents can be simplified.

[0013]

As described above in detail, according to the present invention, the print data storage element for the full dot position and the print data storage element for the half dot position can be used in common, so that the dot print data holding circuit can be reduced. It is possible to do. By reducing the circuit scale, it is possible to reduce the cost of an integrated circuit or a control board containing the dot print data holding circuit.

[Brief description of the drawings]

FIG. 1 is a block diagram of a dot print data holding circuit showing one embodiment of the present invention.

FIG. 2 is a printing timing chart showing one embodiment of the present invention.

FIG. 3 is a block diagram of a dot print data holding circuit configured according to the related art.

FIG. 4 is an explanatory diagram showing an example of the arrangement configuration of hammer pins.

FIG. 5 is a timing chart showing printing timing corresponding to each arrangement of hammer pins.

FIG. 6 is an explanatory diagram illustrating a half dot position.

[Explanation of symbols]

1 is an address switching circuit, 2 is a comparator, 3 is a shift register, 4 is a print data switching circuit, 5 is a selector, and 10 is a hammer pin.

Claims (2)

[Claims] 1. A printing hammer group in which a plurality of printing hammers having hammer pins arranged at substantially equal intervals in the column direction and in a plurality of columns in the row direction are arranged in the column direction, and the printing hammer group is reciprocated in the column direction. A reciprocating means for moving, a storage element for holding dot print data in a control circuit for driving the hammer pin, and a dot position which is a standard print density position as a reference and a density position twice as large as the reference dot position In a dot line printer capable of printing at a dot position, a storage element that stores print data for a dot position, which is a normal print density position, and print data for a dot position, which is twice the normal print density position A dot print data holding circuit for a dot line printer, wherein the storage element for storing the dot print data is shared. 2. An address corresponding to a normal dot density position and an address corresponding to a double-density position are given to the common dot print data storage element, and the addresses are switched according to the dot position, thereby providing a common dot print data storage element. 2. The dot print data holding circuit of a dot line printer according to claim 1, wherein the dot print data at the double density dot position is held alternately.