JPH04363277A - serial printer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer capable of reciprocating printing using a print head mounted on a carriage that moves along a platen.

0002

2. Description of the Related Art It is known that in a serial printer capable of printing in both left and right directions, when printing in both left and right directions, a misalignment of print occurs.

For example, as shown in FIG. 5, an H-shaped figure is printed from left to right, the paper is conveyed a predetermined distance so that the next print does not overlap with this figure, and then the same H-shaped figure is printed at the same position. If you print the figure from right to left, theoretically it should be printed at the same position in the left and right direction, but
Both figures are printed with a difference of length X in terms of their positions in the left and right direction. This is caused by mechanical problems in the drive system that moves the print head, such as gear backlash and belt deflection.

[0004] As a countermeasure for such misalignment of left and right printing,
Conventionally, a person who adjusts a serial printer visually determines the amount of misalignment between left and right printing and sets a correction value, and adjusts the printing start position from left to right or from right to left using the set correction value. Adjustments were made to correct this.

[0005]

[Problem to be solved by the invention] Setting correction values manually takes time and requires sufficient knowledge of how to use a serial printer. There was a problem in that printing misalignment could not be adjusted.

[0006] Moreover, the correction values set by the person who adjusts the serial printer differ slightly depending on the person doing the adjustment.
There are problems in terms of accuracy and reliability. In other words, when manufacturing and selling, there is a problem in that the print quality varies during shipping. Furthermore, there is a risk that left and right printing may be misaligned due to deterioration of parts due to use of a serial printer after shipment.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a serial printer that allows even a person without sufficient knowledge about serial printers to adjust the correction of printing deviations, has no variation in printing quality, and can also correct printing deviations due to aging. purpose.

[0008]

[Means for Solving the Problems] This invention moves a carriage carrying a print head back and forth along a platen,
In a serial printer that performs printing operations on each of the outward and return trips, there is an outward test pattern printing means that prints a test pattern whose detection position is determined in advance during the outward movement of the carriage, and a test pattern that is printed by the outbound test pattern printing means when the carriage moves on the return path. A backward test pattern printing means for printing the same test pattern as the test pattern, and a detection position detecting means fixed to the carriage and detecting the detection position of each test pattern printed by the forward test pattern printing means and the backward test pattern printing means. and a correction value calculation means for calculating a correction value for correcting the deviation of the reciprocating printing based on the difference in the detection position of each test pattern detected by the detection position detection means;
A print correction means is provided for correcting the print start position during one or both of the outward movement and the return movement based on the correction value calculated by the correction value calculation means.

[0009]

[Operation] In the present invention having such a structure, a test pattern whose detection position is determined in advance is printed by the outward test pattern printing means during the outward movement. Next, the same test pattern is printed by the return trip test pattern printing means during the return trip.

Then, the detection position detecting means detects the detection position of each test pattern printed by the forward test pattern printing means and the backward test pattern printing means. The print correction value calculation means calculates a correction value for correcting the deviation in reciprocating printing based on the difference between the two detected positions. During printing, based on the calculated correction value, the printing correction means corrects one or both of the printing start positions during the forward movement and the return movement.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 indicates C constituting the main body of the control section.
It is a PU (central processing unit). a ROM (read only memory) 2 in which program data for processing performed by the CPU 1 is stored; a RAM (random access memory) 3 in which various memory areas used when the CPU 1 performs processing are formed; A nonvolatile memory 4 that stores information that needs to be stored even after the power switch is turned off, such as print correction values, and an interface 5 that is connected to the host computer through a line are connected to the CPU 1 via a system bus 6. There is.

The motor drive circuit 7 drives and controls a paper feed motor 8 for conveying the paper, and also controls whether the paper is black or white or
Paper sensor 9 and print head 10 that detect presence and width
The carriage motor 11 for moving the carriage carrying the is controlled.

The input port 12 receives output signals from the paper sensor 9 and a carriage position sensor 13 composed of an encoder and two counters. In addition,
The carriage position sensor 13 causes two counters to count the pulse output from the encoder in parallel according to normal rotation and reverse rotation. The output port 14 outputs a control signal to a head drive circuit 15 that drives and controls the print head 10 . The motor drive circuit 7, the input port 12, and the output port 14 are connected to the CPU 1 via the system bus 6. FIG. 2 shows the flow of correction value calculation processing performed by the CPU 1 in the self-printing mode. First, the storage area for print correction values formed in the nonvolatile memory 4 is cleared.

Next, one line of black solid printing (from left to right) in which all dots are printed by the print head 10 is executed (forward test pattern printing means). Then, a black test pattern a shown in FIG. 3 is printed on paper b.

The carriage carrying the paper sensor 9 is returned to a position S approximately in the center of the test pattern a. Then, the carriage is moved to the right from this position S by a distance sufficient to cross the end of printing of test pattern a. At this time,
The printing end end A (detection position) of the test pattern is detected by the paper sensor 9 by black and white detection, and the count of the carriage position sensor 13 at that time is taken as a numerical value A. Next, paper b is conveyed a predetermined distance so that the next print does not overlap test pattern a.

When conveyance of paper b is completed, one line of black solid printing (from right to left) is executed using the same printing information as test pattern a (return test pattern printing means). Then, a black test pattern c shown in FIG. 3 is printed on paper b.

The carriage is returned to a position S approximately at the center of the test pattern c. Then, the carriage is moved to the right from this position S by a distance sufficient to pass the printing start end of test pattern c. At this time, the printing start end B (detection position) of the test pattern is detected by the paper sensor 9 by black-and-white detection, and the count of the carriage position sensor 13 at that time is set as B (detection position detection means).

Here, the calculation of B-A is performed to calculate the print correction value (print correction value calculation means), and the calculated print correction value is stored in the print correction value storage area formed in the non-volatile memory. do. FIG. 4 shows the flow of print position correction processing in the normal print mode.

First, it is determined whether printing is from right to left, and if printing is from right to left, the print start position is corrected based on the print correction value (print start position + print correction value) (print correction means). Then, this print position correction process is completed. Furthermore, if the printing is not from right to left, the printing position correction process is immediately terminated.

In this embodiment having such a configuration, in the self-printing mode, a black test pattern is printed from left to right, the end of printing is detected by the paper sensor 9, and at that time, the carriage position sensor is activated. Stop one counter. The count of this counter becomes the value A.

Next, the paper is transported so that the next print does not overlap with the above test pattern, and then a black test pattern is printed from right to left. The printing start end of the test pattern is detected by the paper sensor 9, and the count of the carriage position sensor at that time is read as a numerical value B. Here, the printing correction value is calculated and obtained by B-A.

In the normal printing mode, printing position correction processing is performed for each line printed, and the printing start position of right-to-left printing is corrected based on left-to-right printing. .

As described above, according to the present embodiment, by executing the self-printing mode in advance before issuing normal printouts, the same black test pattern is printed from left to right and from right to left, and these patterns are A correction value for printing from right to left can be determined from the positional shift between the print end and print start ends of the two test patterns. In the normal printing mode, by correcting printing from right to left using the determined correction value, printing can be performed without any printing deviation.

[0025] Therefore, by periodically executing the self-printing mode, a correction value for correcting printing deviation at that point in time can be obtained in response to changes in the serial printer over time.
Right-to-left printing is corrected to match left-to-right printing, allowing printing without misalignment.

Moreover, since it is only necessary to execute the self-printing mode, the correction will not vary depending on the person making the adjustment, and since no special technical knowledge or skill is required, anyone can adjust the correction. . Therefore, when adjusting and repairing a serial printer, there is no need to dispatch a service person, especially for misaligned printing.

In this embodiment, the printing end end or printing start end of the black test pattern printed by solid black printing was detected by the paper sensor as the detection position by black and white detection. A thin non-print line that can be detected perpendicular to the printing direction may be formed in the middle of solid black printing, and this non-print line may be used as a detection position to detect black and white using a paper sensor.

[0028]

[Effects of the Invention] As detailed above, according to the present invention,
Even a person without sufficient knowledge about serial printers can adjust the correction for printing misalignment, and there is no variation in print quality.
It is possible to provide a serial printer that can also correct printing misalignment due to aging.

[Brief explanation of drawings]

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

FIG. 2 is a diagram showing the flow of correction value calculation processing in the same embodiment.

FIG. 3 is a diagram showing an example of printing a test pattern in the self-printing mode of the same embodiment.

FIG. 4 is a diagram showing the flow of print position correction processing in the same embodiment.

FIG. 5 is a diagram showing a printing example showing a conventional example.

[Explanation of symbols]

1...CPU, 4...Nonvolatile memory, 9...Paper sensor, 1
3... Carriage position sensor.

Claims (1)

[Claims] Claim 1: In a serial printer in which a carriage carrying a print head is moved back and forth along a platen and prints on each of the outward and return passes, a test pattern whose detection position is determined in advance is printed during the outward movement of the carriage. an outward test pattern printing means; a return test pattern printing means for printing a test pattern identical to the test pattern printed by the outward test pattern printing means during the return movement of the carriage; A printing means and a detection position detection means for detecting the detection position of each test pattern printed by the return test pattern printing means, and reciprocating printing based on the difference between the detection positions of each test pattern detected by the detection position detection means. correction value calculation means for calculating a correction value for correcting the deviation of the
A serial printer comprising: a print correction means for correcting a print start position during one or both of the outward movement and the return movement based on the correction value calculated by the correction value calculation means.