JPH0798409B2 - Printer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer that performs bidirectional printing, and more particularly to correction of print misalignment due to bidirectional printing.

(Prior Art) In a printer that performs bidirectional printing, when viewed from the front surface of a platen, the print head has a left-to-right direction (hereinafter, referred to as a forward direction) and an opposite right-to-left direction (hereinafter, referred to as a reverse direction). The printer of this type includes, for example, a dot printer. Dot printers that perform bidirectional printing move the print head in the forward or ribose direction by driving the space motor (hereinafter referred to as space operation), and each print head is moved at a fixed print timing synchronized with the timing of this movement. Characters are successively formed by punching pins on a printing paper on the platen.

In recent years, the printing speed of dot printers has been improved by performing such bidirectional printing, but high-quality printing is required with the diversification of graphic printing and image printing. Therefore, there is a need for a printer that causes less print deviation between the forward and reverse directions in bidirectional printing.

The print misalignment and its correction in bidirectional printing will be described below with reference to FIG.

As shown in FIG. 4A, when the print timing in the forward direction is generated, the print in the forward direction is performed with a delay of T ₁ time from the timing. This T ₁ hour is the time required from the print timing signal until printing is performed, and means that it takes T ₁ hour until the print head reaches the print position.

On the other hand, if the print timing signal in the reverse direction is generated at the same timing as the print timing signal in the howard direction, printing in the reverse direction is delayed by T ₁ time from that timing, as in the case of the above-mentioned print in the forward direction. To be done. For this reason, as shown in the drawing, a "deviation", that is, an alignment deviation A (deviation of linearity between the forward printing and the reverse printing) occurs between the printing position in the forward direction and the printing position in the reverse direction. Since this misalignment A is constant between each of the howard printing and the reverse printing, in order to eliminate the misalignment A, the printing position in the reverse direction should be directed toward the drawing so that the misalignment A does not exist at all. You can see that it is better to shift to the right side by pressing. In other words, the print timing signal in the reverse direction may be generated earlier than the print timing signal in the forward direction as a reference. The print misalignment due to such bidirectional printing is fixed in designing the printing speed (because the printing is performed while moving the print head in the printing direction), and as a correction for eliminating the print misalignment, Set a fixed correction value in the printer. Then, the print timing signal in the reverse direction is generated earlier with the fixed correction value of to correct the print misalignment.

Further, the bidirectional printing deviation may not be resolved by the fixed correction value alone. This is due to the secular change of the space motor unit other than the above as the cause of the bidirectional printing deviation. Hereinafter, print deviation due to secular change of the space motor unit will be described with reference to FIGS. 4 (b) and 5. Fig. 5 shows the play caused by the aging of the space motor.
It is a figure which shows a backlash. The space motor part
As shown in the figure, the rack-and-pinion system is used to convert the rotational movement into a linear movement, whereby the print head is moved in the forward or base direction during the printing operation. If you have been using this space motor for many years,
Each rack and pinion are subject to wear and the like, resulting in a very large amount of backlash and backlash as compared with before use at the time of manufacture. If the backlash and backlash are large, the direction of rotation of the space motor is different between the forward printing and the reverse printing. Therefore, as shown in FIG. 4 (b), the printing timing signal in the forward direction and the printing in the reverse direction. This means that the timing signal is effectively delayed by T ₂ time from each timing signal shown in FIG. The correction of the print displacement due to the secular change of the space motor unit is performed by adding the correction change value (including positive and negative) to the fixed correction value, and thereby the print position in the reverse direction is directed toward the drawing. Shifting to the right, that is, a print timing signal in the reverse direction is generated earlier to eliminate misalignment due to backlash and backlash.

In the correction of the printing deviation in the bidirectional printing described above, the printing position in the forward direction is fixed and the opposite target is the printing position in the reverse direction, that is, the dot timing signal.

(Problems to be Solved by the Invention) However, the above-described correction of bidirectional printing misalignment has the following problems.

In order to correct the print misalignment due to the secular change of the space motor unit, the correction change value had to be manually set. Therefore, play of the space motor
Even if bidirectional printing misalignment gradually occurs due to an increase in backlash, the printing misalignment cannot be corrected until the printing misalignment worsens. That is, the correction of the print misalignment is performed only when the print misalignment is detected for the bidirectional printing on the paper, and the print misalignment is not properly performed. .

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide an excellent printer that can automatically correct bidirectional printing misalignment and obtain high printing quality.

(Means for Solving Problems) In order to solve the problems of the prior art, the present invention has a print head drive unit that moves the print head bidirectionally, and synchronizes with the operation of the print head drive unit. The printer for outputting the generated print timing signal to the print head to perform bidirectional printing includes the following means.

The above printer has a print character number calculating means for calculating the print character number from the drive amount of the print head driving part which causes a print deviation due to aging, a print line number coefficient means for counting the print line number, and a print character number. And a storage means for storing the relationship between the number of print lines and a correction point corresponding to a correction amount for correcting secular change, the number of print characters calculated by the print character number calculation means, and the number of print lines counted by the print line number counting means. Is determined to have reached the correction point, and based on the determination result, the print timing correction means for correcting the print timing by selecting the correction value corresponding to the correction point from the storage means is provided.

(Operation) According to the present invention, since the printer is configured as described above, each technical means operates as follows.

In a printer that performs bidirectional printing, print misalignment occurs when the printhead driving unit that moves the printhead bidirectionally changes over time. This is because when the print head drive unit moves the print head with a motor of, for example, a rack and pinion, when the motor is used for many years, backlash and backlash increase due to wear and the like, which causes the print head to move bidirectionally. At this time, printing deviation occurs for each line.
The storage means stores in advance the relationship between the number of print characters and the number of print lines and a correction point corresponding to a correction amount for correcting secular change. The number of print characters is calculated by the print character number calculation means from the drive amount of the print head drive portion that causes the print deviation due to this secular change, and the print line number is counted by the print line number counting means. It is determined whether the calculated number of print characters and the counted number of print lines have reached the correction point, and the print timing correction unit selects the correction value corresponding to the correction point from the storage unit based on the result of the determination and sets the print timing. The correction is performed to correct the above print deviation.

Therefore, according to the present invention, it is not necessary to manually correct the print deviation due to the secular change of the motor as in the prior art, and it is possible to automatically correct the print deviation. Therefore, the conventional problems can be solved.

(Example) Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration relating to automatic correction of print deviation of the printer according to this embodiment. In the figure, 1 is a microprocessor for controlling the operation of the entire printer, and 2 is a microprocessor.
Is a head control circuit for controlling the print of the head 5, 3 is a motor control circuit for controlling the operation of the line feed motor 7 and the space motor 9, and 4 is a head for driving the print head 5 according to a print timing signal from the head control circuit 2. Drive circuits, 6 and 8 are motor drive circuits for driving the line feed motor 7 and the space motor 9 by a signal synchronized with the print timing signal from the motor control circuit 3.
10 is a position sensor that detects the position of the space motor 9, that is, the amount of rotation of the space motor, and outputs the detection result to the motor control circuit 3, 11 is a CGROM that stores and generates print data,
12 is a RAM for storing the preset character type (NLQ, SLANT, etc.) and control modes such as print pitch CPI, CPL, and the total number of printed characters and total number of lines, 13
Is a counter for counting the number of print lines, and 14 is a backup power source for the RAM 12.

In the present embodiment, in the printer having such a configuration, the print deviation due to the secular change (backlash / backlash) of the space motor portion as shown in FIG. 4B is automatically corrected. In addition, in this embodiment, in order to automate the correction, the secular change information of the space motor portion from the manufacturing of the printer to the current use is obtained, and the secular change information is used to determine the backlash and backlash of the space motor. Recognize the corresponding correction change value. Therefore, the total number of characters printed and the total number of printed lines from the time of manufacture to the present are used as parameters for obtaining the information on the change in the total heat of the space motor. This is because when the space motor is driven, the print head performs a spacing operation in the forward or reverse direction for printing, that is, the backlash / backlash of the space motor is closely related to the number of characters printed.

Hereinafter, the printer operation according to the present embodiment, in particular, the automatic correction operation of the bidirectional printing deviation will be described with reference to FIGS. 1, 2, and 3.

2A is a flow chart showing the printing operation of the entire printer, FIG. 2B is a flow chart showing the operation of bidirectional print misregistration correction setting in FIG. 2A, and FIG. 3 is a space motor section. FIG. 6 is a diagram showing the relationship between backlash and backlash due to secular change, the number of print characters, and the number of print lines.

First, in the initial setting of step 100, a fixed correction value for correcting the alignment deviation A shown in FIG. 4A is set in the microprocessor 1 shown in FIG.
By adding the initial correction change value to this fixed correction value, the print deviation due to the space motor portion as shown in FIG. 4B is minimized.

When the microprocessor 1 reads the print data from the CGROM 11 and the RAM 12 (step 101), it processes the print data into a required format and outputs the processed print data to the head control circuit 2 and also the motor control circuit. A motor driving clock pulse is output to the signal No. 3 (step 102). Upon receiving the print data, the head control circuit 2 outputs a print timing signal to the head drive circuit 4 to cause the print head to perform a printing operation. Also, the motor control circuit 3
Outputs a drive signal synchronized with the print timing signal to the motor drive circuit 8 and causes the spacing motor 9 to perform a spacing operation. This means that printing in the forward direction has started.

Next, the operation of the print misregistration correction setting (step 103) will be described with reference to FIG.

When the one-line print output in the forward direction is performed by the above printing operation (step 200), the motor control circuit 3
Represents the movement amount of the space motor based on the output result of the position sensor 10, and the print pitch is 10 CPI (print pitch 10 CPI in this embodiment).
The dot timing signal corresponding to the print pitch of 10 CPI is generated by dividing by the movement amount of the space motor that becomes one character in (PI). That is, the number of characters for one line has been calculated (step 201).
Upon receiving the dot timing signal from the motor control circuit 3, the microprocessor 1 adds and counts the number of characters to obtain the total number of print characters, which is RA
Store in M12 (step 202). Further, the microprocessor 1 drives the line feed motor 7 by the motor control circuit 3 to supply one line of the printing paper, counts the number of lines by the counter 13, and stores the number of lines in the RAM 12 (step 203).

Next, in the reverse direction, the microprocessor 1 adds the preset fixed correction value to the received dot timing signal and gives it to the head control circuit 2. As a result, the head control circuit 2 controls the output of the print timing signal in the reverse direction to align the print alignment in the forward and reverse directions, as shown in FIG. 4 (a). Even when printing in the reverse direction,
The total number of print characters and the number of lines are counted in the same way as when printing in the above-mentioned direction. When printing in one direction (for example, only in the printing in the forward direction), the moving amount of the space motor for one line is doubled and divided by the moving amount of the space motor for one character to obtain the number of characters.

Here, it is necessary to determine when to add the correction change value to the fixed correction value based on the total number of print characters and the total number of lines obtained as described above.

Originally, as shown in FIG. 3, since the backlash and backlash of the space motor increases in proportion to the total number of print characters and the total lines, the correction change value should be gradually increased. It is good, but in the present embodiment, the correction change value is added stepwise every time the amount of backlash / backlash increases in increments of 50 μm in terms of printer performance.
For this reason, the number of characters to be printed for each 50 μm unit of backlash / backlash should be preset in the microprocessor 1.
By setting the number of lines and comparing the set number of print characters / line with the counted total number of print characters / line, the correction change value is added when the target number is reached. The first correction point is when the backlash and backlash is 25 μm.

Returning to the flowchart of FIG. 2 (b), the microprocessor 1 as described above, counts the total number of print characters and the time point when the number reaches the correction point (step
In step 204, add the correction change value to the fixed correction value (step 20
Five). After that, the correction value = until the next correction point is reached
By keeping the fixed correction value + correction change value, the correction change value becomes large for each correction point. As a result, the correction of the print misalignment due to the secular change of the space motor is automatically performed.

Further, by using the backup power supply 14 for the RAM 12, the contents of the RAM 12, that is, the total number of print characters and the total number of lines counted from the time of manufacturing, are set to the power OFF state of the printer.
Sometimes saved.

As described above, in the present embodiment, the correction change value is automatically added in stages with the size of the backlash / backlash in the unit of 50 μm, so that the bidirectional printing deviation of ± 50 μm can be suppressed even in the worst case. You can

Further, in the initial stage, it is necessary to minimize the bidirectional printing deviation by manual operation, but once it is set, the correction will be performed automatically whenever necessary, so that the manual operation as in the past is not necessary.

In this embodiment, the total number of print characters and the total number of lines are calculated in order to obtain the secular change information of the space motor, but the present invention is not limited to this, and it is also possible to obtain it by using only one of the parameters.

(Effects of the Invention) As described in detail above, according to the present invention, a print character number calculation means for calculating the number of print characters from the drive amount of the print head drive unit, which causes print deviation due to aging, Calculated by a print line number counting means for counting the number of print lines, a storage means for storing the relationship between the print character number and the print line number and a correction point corresponding to a correction amount for correcting secular change, and a print character number calculation means It is determined whether the number of printed characters and the number of printing lines formed by the printing line number counting means have reached the correction point, and the correction value corresponding to the correction point is selected from the storage means based on the determination result and printed. Since the print timing correction means for correcting the timing is provided,
Print misalignment due to bidirectional printing can be automatically corrected, and the user's labor can be saved. Further, by automating the correction of the print misregistration, it is possible to continuously obtain high-quality prints, and it is possible to provide a printer excellent in applicability to graphic printing, image printing and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a printer according to an embodiment of the present invention, FIG. 2 is an operation flowchart according to the present embodiment, and FIG. 3 is a backlash / backlash of a space motor unit and total print characters and line numbers. Showing the relationship between
FIG. 5 is a diagram for explaining correction of bidirectional printing misregistration, and FIG. 1 ... Microprocessor, 2 ... Head control circuit, 3 ... Motor control circuit, 4 ... Head drive circuit, 5 ... Head, 6,8 ... Motor drive circuit, 7 ... Line feed motor, 9 ... … Space motor, 10 …… Position sensor, 11 …… CGROM, 12 …… RAM, 13 …… Counter, 14 …… Backup power supply.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kuniharu Hayashi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. Ki Co., Ltd. (56) Reference JP-A-58-163685 (JP, A) JP-A-60-168681 (JP, A)

Claims (1)

[Claims] 1. A printer having a print head drive section for moving the print head in both directions, and outputting a print timing signal synchronized with the operation of the print head drive section to the print head to perform bidirectional printing. , A print character number calculation means for calculating the number of print characters from the drive amount of the print head drive section, which causes print misalignment due to aging, a print line number counting means for counting the number of print lines, and the print character number And storage means for storing the relationship between the number of print lines and a correction point corresponding to a correction amount for correcting the secular change, and the print character number and print line number counting means calculated by the print character number calculation means. It is determined whether or not the counted number of print lines has reached a correction point, and the memory hand is determined based on the determination result. A printer, comprising: a print timing correction unit that selects a correction value corresponding to the correction point from the step and corrects the print timing.