JPH04279367A - Thinning printing control apparatus of serial dot printer - Google Patents

Abstract

PURPOSE:To shorten the thinning processing time of printing data and to enhance the throughput at the time of the execution of high speed printing, in performing the thinning processing of printing data, by performing the thinning processing of an arbitrary number of dots only by once passing the printing data without performing soft program processing requiring a much operation time. CONSTITUTION:A printing data thinning editing circuit DRFT can prepare thinning editing only by arbitrarily setting the thinning number of dots before a central operational processing part CPU performs thinning processing. One-dot thinning, two-dot thinning or the like can be arbitrarily set. When it is necessary to thin printing data DT in high speed printing, only by once passing the printing data DT through the thinning editing circuit DFET by the central operational processing part CPU, printing data is automatically thinned by the quantity corresponding to the set thinning number of dots.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for processing print data in a print output device.

0002

2. Description of the Related Art In conventional serial dot printer printing thinning systems, print data is thinned out using a software program in a central processing unit.

For example, in the case of thinning out one dot by program processing, the first dot data is loaded. Invert the loaded data. Next, load the second dot data. Then, the logical product of the inversion of the first dot data and the second dot data is taken. The procedure is to output the results. In the case of two-dot thinning, the same process is repeated for the third dot data. The known example most related to this method is Japanese Patent Laid-Open No. 59-191643.

0004

[Problems to be Solved by the Invention] However, since the above-mentioned conventional techniques are all performed by software programs, the processing takes time. Especially when performing high-speed printing operations,
The thinning process took time, and there was a delay in sending print data to the head drive unit, which was a bottleneck in increasing speed.

[0005]

[Means for Solving the Problems] The present invention allows printing data to be thinned out once, which is necessary when performing high-speed printing operations, without using software program processing that requires a lot of calculation time. This circuit uses a print data thinning/editing function that allows thinning of any number of dots with just a single touch.

[0006]

[Operation] The print data thinning/editing circuit can prepare for thinning/editing simply by arbitrarily setting the number of dots to be thinned out before the central processing unit performs the thinning process. One-dot thinning, two-dot thinning, etc. can be arbitrarily set.

When it is necessary to thin out print data such as high-speed printing, the central processing unit automatically thins out the print data by the set number of thinning dots by passing the print data through the thinning editing circuit once. Therefore, the thinning processing time is significantly reduced compared to software program processing.

Since the print data is thinned out in a thinning/editing circuit provided in a separate circuit before being sent to the head driving unit, the thinned printing results are the same for positive direction printing and negative direction printing.

[0009]

EXAMPLE An example of the present invention will be demonstrated below with reference to FIG. A central processing unit (hereinafter referred to as CPU) is an arithmetic processing unit that converts commands received from a higher level into print data and operates peripheral circuits. The head drive unit (hereinafter referred to as DRV) is a CP
It receives print data from U and drives the print head to print according to the received print data. The print data thinning and editing circuit (hereinafter referred to as DRFT) has a thinning number arbitrarily set by the CPU using a one-dot thinning signal (A), a two-dot thinning signal (B), and a three-dot thinning signal (C).

[0010] When thinning print data, the CPU
Send print data to T. Inside the DRFT, the received print data is thinned out according to a preset thinning number. The thinned out print data is sent to the CPU. FIG. 2 is an example of one circuit inside the DRFT. If the print data is 8 bits, eight of these circuits are required.

Next, the operation will be explained with reference to FIG. When it is necessary to thin out print data such as high-speed printing, the CPU sets the number of dots to be thinned out in advance using signals (A), (B), and (C). Next, print data is sent to DRFT. Here, the print data corresponds to DT in FIG. First, when DT=1, the data of the first dot is stored in latch F1 and simultaneously sent to AND. If there is no dot data before the first dot, the OR output is '1', so the AND output is '1' and '1' is stored in the latch FM.

Next, the CPU receives the data as DT'=1. Next, the second dot data is sent to the DRFT.
When sent as T=1, F is used as the first dot data.
The data '1' stored in 1 is sent to AND1,
If there is a one-dot thinning signal (A), the AND1 output will be '1' and the OR output will be '0', so even if the second dot data is '1', the AND output will be '0' and will not go to FM. '0' is stored. Next, the CPU receives the thinned-out data '0' as DT'. The same operation occurs in the case of two-dot thinning and three-dot thinning. A similar method can also be used to thin out four dots or more. When executing a printing operation, these thinned printing data are
The PU sends it to the head DRV. If the CPU performs thinning processing when sending print data to the head DRV, the printing results will be different because the thinning method is different for positive direction printing and negative direction printing, but here the print data has been thinned out in advance. Therefore, the printing results can be the same for positive direction printing and negative direction printing.

[0013]

Effects of the Invention According to the present invention, especially when performing high-speed printing, the processing time for thinning out print data can be significantly reduced compared to processing using conventional software programs, and the throughput during high-speed printing can be significantly reduced. can be improved. In addition, compared to conventional software program processing,
Since the processing can be done by hardware, the memory space used by the program for thinning processing can be significantly reduced.
It also has the effect of reducing memory capacity.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is an internal circuit diagram of the DRFT circuit in FIG. 1;

[Explanation of symbols]

CPU...central processing unit, head DRV...head driving circuit, head...print head, DRFT...print data thinning and editing circuit, DT...print data, DT'...thinned print data, F1 to F3...latch, AND1 ~AND3…
AND circuit, OR...OR circuit, (A)...one dot thinning signal, (B)...two dot thinning signal, (C)...three dot thinning signal.

Claims (3)

[Claims] [Claim 1] A serial dot printer in which a central processing unit sends print data to a head drive unit, and the head drive unit drives the print head according to the print data to perform printing, such as high-speed printing operation. 1. A thinning printing control method for a serial dot printer, comprising: a control circuit for thinning out the print data by the print data thinning/editing circuit when the print data needs to be thinned out for the purpose of thinning out the print data. 2. The thinning printing control method for a serial dot printer according to claim 1, wherein the number of thinning dots can be arbitrarily set. 3. According to claim 1, the print data thinning and editing circuit is provided as a separate circuit so that the central processing unit can perform thinning processing in advance before sending the print data to the head drive unit. , a thinning print control method for serial dot printers that makes the thinned print results the same for positive direction printing and negative direction printing.