JPH0528669B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] When a serial printer is operated in the forward and reverse printing mode, the printing misalignment between the printing in the forward direction and the printing in the reverse direction is detected to prevent the printing position from shifting. Automatically correct as follows.

[Industrial application field]

The present invention relates to a control technique for a serial printer, and particularly to a correction device for a printing position shift between a forward direction and a reverse direction in a serial printer.

[Prior art and problems to be solved by the present invention]

Generally, serial printers have a fourth
As shown in the figure, a print head 53 is placed to face the platen 51, and the paper 52 is fed between the platen 51 and the print head 53. 51
It is controlled to move parallel to the axis of the paper 52 and print in line format on the paper 52.

For line format printing motion, forward direction (from left to right)
There are three operating modes: printing, reverse (right to left) printing, and forward/reverse bidirectional (alternating forward/reverse) printing. Normally, the forward/reverse printing mode is used to increase the throughput of the printer.

When printing in the forward and reverse printing mode, slight deviations may occur in the printing positions between forward and reverse printing, mainly due to the accuracy of the printer mechanism such as bumps. There is.

The size of such printing position deviation is usually 1
Although it is smaller than a dot and is not very noticeable when printing characters, when printing continuous vertical ruled lines, the printing misalignment of alternate lines can occur, as shown in Figure 5. The drawback was that it appeared in a zigzag pattern and was easily noticeable.

For this reason, in conventional serial printers, when printing continuous vertical ruled lines, it is common to print in one direction, either forward or reverse, at the expense of throughput performance.

There were also serial printers that could print continuous vertical ruled lines in both directions.
Since the printing position shift changes depending on operating conditions such as temperature, in such a case, an operator or the like has to read the printing results and readjust the hardware frequently, which is a hassle.

[Means for solving problems]

The present invention optically detects the actual printing position for each printing line when vertical ruled lines are printed during the printing operation in the forward and reverse printing mode of a serial printer. The position of the ruled line during printing in the reverse direction is compared with the position of the ruled line during reverse direction printing to determine the deviation, and the timing of feeding control of the printing head is finely adjusted to correct the positional deviation.

FIG. 1 shows the basic configuration of the present invention.

In the figure, 11 is a platen, 12 is paper, 1
3 is a print head, 14 is an optical sensor that moves together with the print head 13, 15 is a feed motor for the print head, 16 is a motor drive circuit, 17 is a print control section, 171 is a continuous vertical line detection section, 172 173 is a ruled line position storage unit, 173 is a ruled line position deviation detection unit, and 17 is a ruled line position storage unit;
4 is a print control timing correction section.

The optical sensor 14 follows the print head 13 to optically scan the surface of a pattern such as characters or ruled lines printed on the paper 12 by the print head 13, and converts it into an electrical signal.

The print head feed motor 15 is a step motor and is driven by a motor drive circuit 16.
The print head 13 and optical sensor 14 are moved in the forward or reverse direction during printing operations.

The print control section 17 controls the feeding of the print head 13 based on the input print data, applies a corresponding dot pattern signal to the print head 13, and controls printing at a predetermined position. Correction of print position deviation in the present invention is executed within this print control section 17.

The continuous vertical ruled line detection unit 171 detects the position of a continuous vertical ruled line code printed over a plurality of lines in the input print data in the forward and reverse printing mode.

When continuous vertical ruled line printing is performed, the ruled line position storage unit 172 detects the printing position for both forward and reverse printing from the signal obtained when the optical sensor 14 scans, and stores it as a vertical ruled line position pattern. do. The forward and reverse scanning of each print line by the optical sensor 14 is performed only in one direction (for example, the forward direction) in order to align the positional reference.

The ruled line position deviation detection unit 173 examines the vertical ruled line position pattern stored in the ruled line position storage unit 172 and detects the deviation between printing in the forward direction and in the reverse direction. The print control timing correction unit 174 shifts the print timing in a direction in which the positional deviation is corrected, based on the positional deviation detected by the ruled line positional deviation detection unit 173.

[Effect]

According to the present invention, each time continuous vertical ruled line printing is performed while the serial printer is performing actual printing operation in the forward and reverse printing mode, either constantly, periodically, or in response to an operator's instruction, It is possible to automatically correct positional deviations in the forward and reverse directions.

Continuous vertical ruled line printing is detected by checking whether or not there is a digit position where the vertical ruled line code matches between successive line print data.

In each forward/reverse printing line, the output of the optical sensor 14 is taken in as a vertical ruled line position pattern only from the printing area of the detected vertical ruled line, and for example, it is sliced and converted into a binary value, or A/D converted and multivalued. The level data is stored in the ruled line position storage unit 172 in association with the absolute position.

FIG. 2a shows a pattern of continuous vertical ruled lines in a forward printing line and a reverse printing line, in which solid arrows indicate the printing direction and dotted arrows indicate the optical sensor scanning direction. FIG. 2b shows the optical sensor output as a result of optically scanning the vertical ruled lines in each print line. FIG. 2c shows the ruled line position deviation detection unit 1.
73 shows positional deviation information detected by 73. Second
Figure d shows the print timing pulse and Figure 2e
represents a print control pulse. The timing of the print control pulse is corrected based on the positional deviation information using the print timing pulse as a reference point.

The print control timing correction unit 174 corrects the positional deviation error by shifting the phase of the print control pulse in printing in either the forward direction or the reverse direction based on the positional deviation information.

〔Example〕

FIG. 3 shows the configuration of one embodiment of the present invention.

In the figure, 13 is a print head, 14 is an optical sensor, 17 is a print control section, 31 is an amplifier, 32 is a pulse shaping circuit, 33 is a sampling circuit, 34 is a shift register, 35 is a vertical ruled line position memory, 36
37 is a positional deviation detection logic circuit, 37 is a deviation amount register, 38 is a forward direction deviation display FF, 39 is a reverse direction deviation display FF, 40 is a variable delay circuit, 41 is a multiplexer, 42 and 43 are AND circuits, and 44 is a
An OR circuit, 45 is a print control pulse, and 46 is a correction print control pulse.

The optical sensor 14 follows the printing by the print head 13 and displays the printed character pattern surface. Note that the scanning width (vertical width) may be, for example, one dot to several dots.

In the print control section 17, an amplifier 31 amplifies the output signal of the optical sensor 14, pulse-shapes it in a pulse-shaping circuit 32 such as a slice circuit or a Schmitt trigger, and samples it in a sampling circuit 33. The sampling circuit 33 is driven by a vertical ruled line extraction signal that turns ON only at the vertical ruled line printing position and a sampling pulse with a fine period that can divide the dot width into multiple parts, and converts the input signal into a binary pulse train of 0 and 1. The data is converted and sequentially written into the shift register 34.

Here, the vertical ruled line extraction signal is synchronized with the print timing signal, and is normally timed when the print head passes a reference point provided at the left or right end of the platen.

Therefore, the vertical ruled line position pattern written in the shift register 34 is cut out using the same positional reference for printing lines in either the forward or reverse direction.

The vertical ruled line position pattern extracted in the shift register 34 for each print line in the forward direction and reverse direction is as follows:
Each is stored at a separate address in the vertical ruled line position memory 35.

The positional deviation detection logic circuit 36 compares the vertical ruled line position patterns for printing in two directions, normal and reverse, stored in the vertical ruled line position memory 35, and determines, for example, the amount and direction of deviation between printing in the reverse direction and printing in the forward direction. If the amount of deviation is larger than a predetermined threshold, the amount of deviation is stored in the deviation amount register 37, and if the deviation is in the positive direction (rightward), a positive direction deviation is displayed FF 38. ON
If the deviation is in the opposite direction (to the left), set the reverse direction deviation display FF39 to ON.

The variable delay circuit 40 is, for example, a variable timer, and delays the input print control pulse 45 according to the amount of deviation stored in the deviation amount register 37. The multiplexer 41 selects the output or input of the variable delay circuit 40 depending on whether correction is necessary or not, and outputs it as a correction print control pulse 46.

The AND circuits 42, 43 and the OR circuit 44 are circuits for controlling the timing of selecting a print line to be corrected for positional deviation.

When the positive direction deviation display FF 38 and the positive direction printing signal are ON, the AND circuit 42 sends a control signal to shift the vertical ruled line printing in the positive direction printing line in the positive direction (to the right) via the OR circuit 44. and gives it to the multiplexer 41. As a result, the vertical ruled line in the forward printing line is corrected to be shifted in the positive direction so that it matches the vertical ruled line in the reverse printing line that is shifted in the positive direction.

When the reverse direction shift display FF 39 and the reverse direction printing signal are ON, the AND circuit 43 sends a control signal to shift vertical ruled line printing in the reverse direction print line in the reverse direction (to the left) via the OR circuit 44. and gives it to the multiplexer 41. As a result, the vertical ruled line in the reverse printing line is corrected in the opposite direction (to the left) so as to match the position of the vertical ruled line in the forward printing line.

By using a non-volatile memory instead of the deviation amount register 37, continuous vertical ruled lines can be printed without any positional deviation even when the power is turned off and then turned on again.

Furthermore, in the embodiment described above, the positional deviation of vertical ruled lines in separate printing lines in the forward direction and reverse direction is compared and the position of one of them is corrected. , prints overlapping vertical ruled lines in the forward and reverse directions on the same line, and automatically adjusts the amount of misalignment correction to minimize the width by taking advantage of the fact that the width of the printed vertical ruled line becomes thicker as the misalignment increases. It is also possible to adopt a method of repeating trial printing while making changes.

〔Effect of the invention〕

According to the present invention, at the time of the spinal cord or periodically,
Alternatively, when specified by an operator, when vertical ruled line printing is performed, it is possible to automatically correct the printing position deviation for both forward and reverse printing. Printer can be provided.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the basic configuration of the present invention, Fig. 2 is an operation timing diagram of the principle configuration according to the present invention, Fig. 3 is a block diagram of an embodiment of the present invention, and Fig. 4 is a diagram of a conventional serial printer. The basic configuration diagram, FIG. 5, is an explanatory diagram of continuous vertical ruled lines with misalignment. In Figure 1, 12: Paper, 13: Print head, 1
4: optical sensor, 15: feed motor, 17: print control section, 172: ruled line position storage section, 173: ruled line position deviation detection section, 174: print control timing correction section.

Claims (1)

[Scope of Claims] 1. In a serial printer capable of printing in both forward and reverse printing formats, when consecutive vertical ruled lines are printed in both forward and reverse printing formats, the number of characters printed in each of the forward direction printing and reverse direction printing is The position of the signal output from the optical sensor 14 in detecting each vertical ruled line in the above-mentioned forward direction printing and reverse direction printing is compared with the optical sensor 14 that detects the vertical ruled line, and the position between the forward and reverse direction printing is determined. A means 173 for detecting the size of the deviation based on a sampling pulse having a cycle finer than the dot width, and an appropriate printing control timing for one or both of forward printing and reverse printing based on the detected positional deviation. 1. A printing position deviation correction device for a serial printer, comprising: a shifting means 174, and automatically correcting position deviations during printing in both forward and reverse printing formats.