JPS60248378A - Controller for serial printer - Google Patents

Abstract

PURPOSE:To prevent the slipage of printing positions from being generated between lines in forward and backward shortest printing and print vertical lines or graphic patterns in shape at high speed, by providing a means for compensating for the effect of backlash in a printing head driving system. CONSTITUTION:Printing data are inputted into a DMA controller 10 through an input port 22, and are converted into patterns as image data by a character generator 12, and the patterns are stored in a buffer. According to a program stored ito a program memory (ROM, RAM) 11 through the input port 22, a set point on a compensating switch 23 is read into a RAM address designated by a microprocessor 24. A microprogram operates under the control of an OSL-controlling program. This operation consists of initialization (a) on turning ON a power source, data input interrupt (c), encoder signal interrupt (d), printing (e) and paper feeding (f).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a serial wire dot printer, and in particular,
The present invention relates to a serial printer control device suitable for bidirectional printing, vertical line printing, and graphic printing.

[Background of the invention]

When trying to print vertical lines or graphics with a conventional serial printer, if the shortest printing is done in both directions, backlash in the drive system mechanism will inevitably cause some printing misalignment from line to line, which will affect the print quality. To prevent this, unidirectional printing was used.

However, in this case, there was a serious drawback that the printing speed was reduced to about 1/2.

[Purpose of the invention]

An object of the present invention is to provide a means for correcting the effect of backlash in the print head drive system, to print in the shortest possible length in both directions, to eliminate line-by-line printing misalignment, and to print vertical lines or graphics in an attractive manner at high speed. The goal is to provide the means to do so.

[Summary of the invention]

Backlash in the mechanical drive system is unavoidable, but since there are variations between individual products, the present invention sets the correction amount in advance with a switch, and when changing the printing direction from the forward direction to the reverse direction using a microprogram, the space dot By printing the following, it was decided to correct the equality constraint.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 shows the configuration of a serial printer. The control circuit 1 drives the paper feed motor with an output a, drives the carriage motor with a signal, moves the print head 5 in the row direction, and controls the print position with a carriage position signal d output from the encoder 4. Reference numeral 6 denotes a power supply section, which supplies C power when necessary. Reference numeral 7 denotes an operation unit for operating the power switch and local mode operation.

FIG. 2 shows the configuration of the drive system. The carriage motor is controlled by the output from the control circuit, and drives the print head 5 attached to the guide shaft 8 in forward and reverse directions via a timing belt.

On the left edge, a home position sensor detects the left edge position of the print. With these, backlash in the rotational system is unavoidable, and there is play when reversing in the opposite direction.

As an example, consider printing a connecting line. For example, −
The character data pattern of the line is written to the image data buffer and becomes as shown in FIG. 3(a). This pattern data is sequentially incremented by 1 from address α in the buffer memory and printed on paper. - When characters can be composed of n columns, for 7 lines of m characters, up to addresses α+n x m -1 are printed. When the pattern shown in Figure 3 (a) is printed in both directions, if it is printed in the forward direction from the left end where the home sensor reference position is located, and turned in the opposite direction at the right end,
Due to backlash, as shown in No. 313(b), printing shifts by an amount of r, which does not result in a clean connecting line. It is obvious that if only forward printing is used and printing is always performed from the home position sensor position, the effective printing speed will be approximately 1/2. Therefore, in order to eliminate this defect and obtain a clean connection line, it is necessary to correct the backlash by some means.

FIG. 4 shows an embodiment of the present invention.

The microprocessor 24 operates based on the timing signal generated by the control circuit 19. The print data is sent to the character generator 12 as image data by the DMA controller 10 via the input port 22. , is stored in the buffer.The timing signal from the encoder is read into the microprocessor via 13 and 14.The microprocessor also controls the print drive circuit 16, motor drive circuit 17, and operation section 18, respectively. Now, the set value of the correction switch 23 is read into the R and AM addresses specified by the microprocessor by the program stored in the program ROM 11 via the input port 22.

The microprogram operates in the configuration shown in FIG. 5 under the control of the O8L management program. Initial processing when power is turned on, data human interrupt.

Consists of encoder signal interrupt, print processing, and single paper feed processing. Details of the encoder signal processing are shown in FIGS. 6(a) and 6(b). The signal output of the encoder is read in step 62, and the traveling direction is determined in step 63. If the direction of travel is reversed, furthermore, in step 67, it is detected that the direction has changed from the forward direction to the reverse direction.

When the number of pits has changed, the column-converted value of the number of pits set by the correction switch is added to the carriage position counter in the RAM in step 68. In step 69, space data is set in the corresponding buffer address. Thereafter, in step 70, the carriage position counter is counted down every time one line is printed. This space printing corrects the deviation due to backlash, making it possible to print at the correct position. If printing is performed in the forward direction, the carriage position counter is incremented by 1 in step 64, and in step 75, printing is similarly performed for each row. In addition, in step 72, if the position is before the print start position, the process returns without counting, and in the case of the print start position, in step 73, the image buffer lj
Set the address of AM and return. Therefore, in the forward direction, printing is always performed from the starting position. According to this method, a side effect is that changes over time can be re-established during maintenance. In addition, the image sensor
It is also possible to detect using
Difficult to implement.

〔Effect of the invention〕

According to the present invention, since the influence of backlash can be eliminated without performing unidirectional printing, the printing speed can be doubled even during vertical line and graphic printing compared to conventional unidirectional printing.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a serial printer, Fig. 2 is an explanatory diagram of the structure of the drive unit, Fig. 3 is an explanatory diagram of conventional problems, and Fig. 4 is an illustration of the structure of the drive unit.
5 is a block diagram of an embodiment of the present invention, FIG. 5 is an overall configuration diagram of a program, and FIG. 6 is a flowchart showing a correction method of the present invention. 22...Input port, 23...Correction switch. Agent Patent Attorney Akio Takahashi 1st m 20th 32nd <C) 40th 50th Figure 6

Claims (1)

[Claims] 1. Consists of a print paper feed motor, a print head, a carriage motor that moves the print head in the row direction, an encoder that detects the position of the carriage, a control circuit that controls these, and a core part. , a serial printer control device that performs shortest printing in both directions, which is equipped with a microprocessor, means for presetting a correction value for MA drive system backlash, a circuit for reading the correction value into the microprocessor, and the microprocessor. However, the electric ratio r section is drawn in the 14J-shaped direction,
A serial printer characterized in that the head is moved by the column-converted value of the setting value prior to printing actual character data, thereby correcting backlash in the drive mechanism section and performing high-speed bidirectional printing. Control device.