JPH04128064A - Printing apparatus - Google Patents

Abstract

PURPOSE:To perform draft printing generating no printing shift even when bidirectional printing is performed, in a printing apparatus performing thinning printing with respect to printing data consisting of a plurality of vertical double em characters, by providing a draft means performing thinning processing by one character with respect to the printing data and a means printing the printing data subjected to thinning processing by one character. CONSTITUTION:A draft circuit 4 is constituted of flip-flops (hereinbelow referred to as FF) 40, 43, an NAND circuit 41, an AND circuit 42 and a delay circuit 44. A known D-type FF is used as each of FFs 40, 43 and printing data is held by one bit in synchronous relation to a clock CLK for transmitting printing data. The data after the thinning processing due to the draft circuit 4 is inputted to a selector 3 and the selector 3 has function alternately outputting printing data 32 not subjected to thinning processing and the printing data 33 after thinning processing to the printing buffer of the next stage corresponding to the control signal from a CPU 7. By this constitution, even when a vertical double em character is subjected to bidirectional printing, the generation of printing shift can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a printing device, and particularly to a printing draft (thinning) method during high-speed bidirectional printing.

2. Description of the Related Art In general, printing apparatuses perform print drafting (thinning) during high-speed printing to achieve high-speed printing that exceeds the performance of the print head.

Further, when performing print drafting in a conventional printing device, printing data is inputted into a drafting circuit at the time of printing, and the data is compared with the most recent data. For example, when a certain dot is determined to have data, printing is not performed on the next dot, and processing moves on to the next dot. This relatively improves the impact processing performance of the head pins of the print head, achieving twice the performance of the print head itself and performing high-speed printing.

In the conventional draft method described above, printing can be performed from one direction without any particular problem. However, when printing double-height character print data in both directions, CW (C1o
ck Wise) direction and CCW (Counter
This method has the drawback that scanning is performed from both directions (C1ockwise), resulting in a one-dot printing misalignment.

For example, as shown in Figure 4(a), when a vertical ruled line with two horizontal dots is printed in both directions using the conventional draft method, the printing will be misaligned as shown in circle A and will no longer be in a straight line. . Furthermore, as shown in Fig. 4(C), when double-height characters rHJ are printed in both directions as indicated by arrows Y1 and Y2 using the conventional draft method, printing misalignment occurs and the vertical lines are misaligned. It will happen. Such printing misalignment has the drawback of significantly impairing the printing quality of the printing device.

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and its purpose is to provide a printing device that can perform draft printing without causing print misalignment even when printing in both directions. That's true.

Structure of the Invention A printing device according to the present invention is a printing device that performs thinning printing on print data consisting of a plurality of double-height characters, and comprises:
The present invention is characterized by comprising a draft means for thinning out the print data one character at a time, and a means for printing the print data thinned out one character at a time.

Example Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a printing device according to the present invention, and shows an example of the configuration of a device for printing double-height characters for full-width characters of 24×24 dots. The apparatus of this embodiment differs from the conventional apparatus in that the print data is stored in a buffer after the thinning process, and the stored print data is printed. In other words, unlike the conventional method in which data is thinned out when reading and printing data stored in a buffer, the print data after being thinned out character by character is stored in a buffer, read out, and printed. Because we adopt the method of
Printing scratches do not occur even when printing in both directions.

In order to realize this, the printing device of this embodiment uses the selector 3.
a CPU 7 that performs switching control, etc., a draft circuit 4 that performs thinning processing character by character on print data from the CPU 7, and a print buffer 1 that holds print data for CW.
, a print buffer 2 for holding print data for CCW, and 12-bit latch circuits 5 and 6.

Further, the outputs of the latch circuits 5 and 6 are applied to a print head (not shown).

In this way, the print data after thinning out each character is held in the print buffer, read out, and printed in both directions, so that no printing misalignment occurs.

Note that one column of 24 vertical dots is printed using a total of 24 bits of the 12-bit latch circuit 5 and the 12-bit latch circuit 6, and by repeating this 24 times from right to left, 2 lines are printed.
Printing of full-width characters of 4×24 dots is completed. Also, since print buffer 1 is for CW, data is stored when printing from left to right, and print buffer 2
Since this is for CCW, data is stored when printing from right to left.

Next, the internal configuration of the draft circuit 4 will be explained.

FIG. 2 is a block diagram showing the internal configuration of the draft circuit 4. As shown in FIG. In the figure, the draft circuit 4 includes flip-flops (hereinafter abbreviated as FF) 40 and 43, and a NAND (NA
The circuit includes an ND (ND) circuit 41, an AND circuit 42, and a delay circuit 44.

Well-known D-type FFs are used for the FFs 40 and 43, and the print data is held one bit at a time in synchronization with the print data transfer clock CLK. Here, both FF
Since a NAND circuit 41 and an AND circuit 42 are provided between them, the delay circuit 4 is used for adjusting the holding timing.
4 is provided.

In this configuration, the FF 43 stores print data (binary data) at the immediately preceding dot, that is, at the left dot (binary data) when scanning from left to right. This FF
Since the output of 43 is input to the NAND circuit 41, it is NANDed with the print data (binary data) for the current dot.

The NAND result is further input to an AND circuit 42, where it is ANDed with print data (binary data) for the current dot. Then, the AND result is transmitted to the next stage circuit as draft data and is held in the FF 43.

Next, the operation of this draft circuit 4 will be explained using FIG. 5. FIG. 5 is a truth table showing the operation of the traft circuit 4, and shows the output values of the NAND circuit 41 and the AND circuit 42 for the values of data held in the FFs 40 and 43. In this truth table, dots that are printed are shown as "1", and dots that are not printed are shown as "0".

First, referring to ■ and ■ in Fig. 5, if the value of the print data for the current dot, that is, the data held in FF40, is "0", the print data for the immediately previous dot, that is, the data held in FF43, is "0". Value is “0° or “1”
”, the output value of the NAND circuit 41 is “1”.
", and the output value of the AND circuit 42 is "0". In other words, if the print data is "0", that is, if there is no line part, the thinning process is not performed.

On the other hand, referring to ■ and ■ in FIG. The output value of the AND circuit 42 differs depending on the data value.

That is, as shown in (■) in FIG. 5, when the print data for the immediately preceding dot, that is, the value of the data held in the FF 43 is "1", the thinning process is performed. Therefore, in this case, the output value of the AND circuit 42 is "0'"
becomes.

On the other hand, if the value of the print data for the immediately preceding dot, that is, the value of the data held in the FF 43, is "0", as shown in (■) in FIG. 5, the thinning process is not performed. Therefore, in this case, the output value of the AND circuit 42 is "1".

The above-described thinning process is performed for each 24 x 24 dot full-width character one by one. In other words, the same configuration as shown in Figure 2 is provided for 24 bits, 24 vertical dots for one character are stored in the FF at one time, and this is repeated 24 times from left to right.
The thinning process for double-byte characters of X24 dots is completed. Note that only one configuration of Fig. 2 is provided, and the top 24 dots of 24 x 24 dots are processed from left to right, and then the 24 dots are processed from the top to the bottom.
It is also possible to repeat the process several times.

In addition, in the case of double-height characters of 48 x 24 dots, 24
The thinning process for X24 dots is repeated twice. In this case, 24X2 of the upper half of 48X24 dots
For 4 dots, 24 vertical dots are repeated 24 times from left to right, and for the 24×24 dots in the lower half, 24 vertical dots are repeated 24 times from left to right. In this way, by making the direction of the first thinning process of 24x24 dots and the direction of the second thinning process of 24x24 dots for a double-height character of 48x24 dots the same direction, and performing this for each character. During actual printing, even if printing is performed in both directions, the printing misalignment that occurs in the conventional method does not occur.

By the way, referring again to FIG. 1, the data after being thinned out by the draft circuit 4 is input to the selector 3. As shown in FIG.
It has a function of selectively sending unthinned print data 32 and thinned print data 33 to the next print buffer in response to a control signal 31 from the PU 7.

Since this selection method is adopted using a selector, normal printing and thinning printing can be freely selected by simply changing the value of the control signal 31, although the configuration is simple.

As described above, when the thinning process is performed, the vertical ruled line of 2 horizontal dots becomes thinned data without any deviation when it is stored in the print buffer, as shown in FIG. 4(b). Therefore, even if printing is performed in both directions, printing misalignment will not occur.

Also, for the rHJ double-height character, it is already thinned data with no deviation as shown in FIG. 4(d) when it is stored in the print buffer, so the arrow Y1
Even if printing is performed in both directions as in Y2 and Y2, no printing misalignment occurs, and no misalignment occurs on vertical lines.

Note that, according to this embodiment, even in the case of unidirectional printing instead of bidirectional printing, printing scratches do not occur as in the conventional case. In other words, according to the present invention, it is possible to realize a printing device that does not cause printing misalignment regardless of the printing direction.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention performs thinning processing on print data one character at a time, and prints the data after the thinning processing, so that printing misalignment occurs even when double-height characters are printed in both directions. It has the effect of not doing so.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the main parts of a printing device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the internal configuration of the draft circuit in FIG. 1, and FIG. 3 is a block diagram showing the internal configuration of the draft circuit in FIG. Block diagram showing the connection relationship of selectors, FIGS. 4(a) and (c)
) is a schematic diagram showing an example of printing by a conventional printing device, FIGS. 4(b) and (d) are schematic diagrams showing an example of printing by the printing device of FIG. 1, and FIG. This is a truth table showing the operation. Explanation of symbols of main parts 1.2...Print buffer 3...Selector 4...Draft circuit

Claims (1)

[Claims] (1) A printing device that performs thinning printing on print data consisting of a plurality of double-height characters, including a draft means that thins out the print data one character at a time, and a draft means that thins out the print data one character at a time; 1. A printing device comprising means for printing printed data.