JP2815168B2 - Line feed control method for printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] In a printing apparatus that performs printing by dots, a line feed control of a printing apparatus that can maintain an accurate sheet feed amount when printing one line is repeated a plurality of times. With regard to the method, with the aim of improving the accuracy of the paper feed amount economically, while moving in the direction perpendicular to the paper feed direction, a plurality of printing elements arranged along the paper feed direction are driven, and one line is printed on the paper. And a paper feed mechanism that executes a small line feed that feeds a small amount of paper when printing the same line a plurality of times and a large line feed that feeds the paper to the next line. In a printing apparatus that performs printing by repeatedly executing line feed, a correction value predetermined for the paper feed amount is stored, and if the paper feed amount indicates a minute line feed, the correction value is set to the paper feed amount. The paper feed is executed with the paper feed amount obtained by adding the correction value, and if the paper feed amount indicates a large line feed, the paper feed is executed with the paper feed amount obtained by subtracting the correction value from the paper feed amount.

[Industrial applications]

The present invention relates to a printing apparatus that performs printing by dots, and in particular, performs printing of one line repeatedly a plurality of times, in other words, corrects printing of one line by moving a printing element a plurality of times. The present invention relates to a line feed control method for a printing apparatus that can maintain a paper feed amount.

In a printing device such as a dot printer that prints characters and graphics by dots, a plurality of pins arranged in parallel with the paper feed direction are driven to move the printing mechanism for printing dots in a direction perpendicular to the paper feed direction. Minute printing.

By the way, in order to improve the printing density of a dot row for one line printed by the printing mechanism, printing for one line is repeated a plurality of times. That is, for example, when one line of printing is repeated twice to complete the printing, the first printing is performed,
The paper is slightly moved so that a dot is printed at the center of the pin interval, and then the second printing is performed.

However, when such a small amount of paper is fed, the amount of paper actually fed becomes smaller than the amount instructed by the control means, but it is necessary to prevent such inaccurate paper feeding. .

[Conventional technology]

 FIG. 4 is a view for explaining an example of the sheet feeding mechanism.

With the rotation of the motor 1, the platen 5 is driven to rotate via a speed reduction mechanism composed of a plurality of gears 2 to 4. The sheet 7 is sandwiched between a platen 5 and a roller 6 which is in close contact with the platen 5 and rotates freely, and is fed as the platen 5 rotates.

In this way, the paper feed is executed,
It is desirable that the speed reduction mechanism constituted by 4 has a large reduction ratio when the feed amount of the paper 7 is small and a small reduction ratio when the feed amount of the paper 7 is large.

This means that when the sheet feed amount is minute, the rotation amount of the platen 5 is minute, and unless the reduction ratio of the speed reduction mechanism is large, the rotation amount of the rotating shaft of the motor 1 is small and the accurate sheet feed amount is controlled. This is because when the feed amount of the paper 7 is large, and when the reduction ratio is large, the paper feed time becomes long.

However, in the printing apparatus, since various types of paper feed amounts are required, it is difficult to satisfy the optimum reduction ratio of these two.

[Problems to be Solved by the Invention] In order to improve the printing density of one row of dot rows to be printed by the printing mechanism, it is necessary to complete the printing of one row a plurality of times, as described above. Needs to feed a small amount of paper. However, when a small amount of paper is fed by a paper feed mechanism having a speed reduction mechanism as shown in FIG. 4, the rotation of the rotating shaft of the motor 1, the transmission loss of the rotation force of the speed reduction mechanism, and the stationary state of the speed reduction mechanism and the platen 5 etc. Due to the influence of frictional force and the like, paper 7
Is reduced, but the reduced amount of movement is not negligible with respect to the small amount of sheet feed required for the sheet 7.

This is, as described above, when the paper feed amount is minute,
Since the reduction ratio of the reduction mechanism is not large and the reduction ratio is not suitable for this minute feed amount, the rotation amount of the rotating shaft of the motor 1 is small, and the rotating amount of the rotating shaft of the motor 1 corresponds to the static friction force. This is because they are accumulated in the torsion of the rotating shaft or absorbed by transmission loss of the reduction mechanism or the like.

Therefore, in order to accurately transmit the minute sheet feed amount to the sheet 7, the rigidity of the rotating shaft of the motor 1 is increased, the transmission loss generated in the reduction mechanism is reduced, and the power transmission loss to the sheet 7 by the platen 5 and the roller 6 is reduced. And the like, and there is a problem that the paper feeding mechanism becomes complicated and uneconomical.

In view of such a problem, the present invention corrects the rotation amount of the motor 1 in consideration of the amount of movement of the paper 7 in accordance with the paper feed amount, thereby preventing the paper feed mechanism from becoming complicated. It is an object of the present invention to provide a line feed control method which is economical and has a high accuracy of the sheet feed amount.

[Means for solving the problem]

 FIG. 1 is a diagram for explaining the principle of the present invention.

FIG. 1A is a block diagram showing an example of the configuration. The control means 10 of the printing apparatus 9 moves in a direction perpendicular to the sheet feeding direction based on a command given from the host apparatus 8 and print data. A printing mechanism 12 that drives a plurality of printing elements arranged in the paper feed direction to print one line on paper, and a fine line feed and a next line that feed a small amount of paper when printing the same line a plurality of times. The paper feed mechanism 13 that executes a large line feed that performs the sheet feed up to the above is controlled so that the small line feed and the large line feed are alternately and repeatedly executed to print characters, figures, and the like.

That is, the control means 10 stores a predetermined correction value for the paper feed amount included in the print data from the host device 8 in the storage means 11, and the paper feed amount sent from the host device 8 indicates a minute line feed. Paper feed mechanism 13
The storage unit 11 stores the sheet feed amount sent from the host
The paper feed is executed by the paper feed amount obtained by adding the correction value stored in.

When the sheet feed amount sent by the upper device 8 indicates a large line feed, the sheet feed amount obtained by subtracting the correction value stored in the storage means 11 from the sheet feed amount sent by the upper device 8 to the sheet feed mechanism 13. Execute the paper feed.

FIG. 1 (b) is a diagram for explaining an operation in which the control means 10 controls the paper feeding mechanism 13 when the printing density of the printing mechanism 12 in FIG. 1 (a) is doubled, and FIG. 1 (c). FIG. 4 is a diagram illustrating an example of a case where printing is performed at twice the printing density.

In FIG. 1B, the vertical axis indicates the amount of paper movement, and the horizontal axis indicates the elapsed time. When doubling the printing density, the host device 8
When an instruction to print a line in the vertical direction is given to the control means 10 from the printer, the printing mechanism 12 prints the sheet on the paper as shown in FIG.
The dot row is printed as shown in FIG. Next, the host device 8 instructs the control means 10 to feed a small amount of paper as shown in FIG. 1 (b), and instructs a line feed. This sheet feed amount is half the dot interval shown in FIG. 1C, and specifies that the sheet is fed to the position shown in FIG. 1B.

At this time, when the control unit 10 recognizes that the paper feed amount instructed by the host device 8 is small and the line feed is minute, the control unit 10
11 is read in advance, the correction value as shown in FIG. 1 (b) is added to the sheet feed amount sent by the host device 8, and a line feed is instructed to the sheet feed mechanism 13.

The paper feed mechanism 13 supplies a drive current to the motor 1 shown in FIG. 4, and rotates a rotation amount corresponding to the paper feed amount instructed by the control means 10. That is, the rotation is performed in accordance with the amount of movement to the position with time as shown in FIG. But,
As described above, in response to the static frictional force, the rotation shaft of the motor 1 is twisted, the transmission loss of the reduction mechanism is generated, and as shown in FIG. The paper is fed out and stops at the position shown in.

 This period will be described in detail.

Even if the motor 1 starts rotating, the platen 5 does not rotate immediately, and the rotation of the platen 5 is delayed with respect to the rotation of the motor 1 as shown in FIG. The reason is that a transmission system such as a motor shaft, a gear transmission mechanism, and a platen shaft is twisted. This torsion is caused by the static friction, and it is considered that the rotation of the platen 5 is not substantially performed until the static friction force is overcome, and the rotation starts only when the rotational force of the platen 5 exceeds the static friction force. That is, the rotation of the motor 1 is performed prior to the rotation of the platen 5.

When the rotation of the platen 5 starts, the twist accumulated in the transmission system such as the motor shaft, the gear transmission mechanism, and the platen shaft is gradually released.
Try to catch up with the rotation of. However, when the rotation amount of the motor 1 is instructed, in other words, when the line feed amount of the instructed sheet is very small, all of the accumulated twists cannot be released, and accordingly, the movement amount of the motor 1 is instructed. The amount of movement of the platen 5 is reduced by an amount that cannot be released, but since the correction amount is added as described above,
The movement amount is larger than in the conventional case where no correction is made.

The position indicated by this varies due to variations such as the static frictional force of the paper feed mechanism 13 and the transmission loss of the speed reduction mechanism.

Here, the control means 10 causes the printing mechanism 12 to perform printing again according to an instruction from the host device 8. In this case, the distance-is a small amount of deviation from the print density and is negligible. Accordingly, as shown in FIG. 1 (c), a dot row superimposed on the dot row indicated by is printed. That is, a dot row whose print density is doubled is printed as shown in FIG.

The host device 8 instructs a line feed by instructing a paper feed amount for line feed to the next line, following the instruction of printing by minute line feed. That is, the movement amount shown in FIG. 1B is indicated. Therefore, when the control unit 10 recognizes that the line feed is a large line feed from the movement amount, the control unit 10 reads the correction value stored in advance in the storage unit 11 and shows the correction value stored in the storage unit 11 as shown in FIG. Subtracting the correction value
A line feed is instructed to the paper feed mechanism 13.

The paper feed mechanism 13 supplies a drive current to the motor 1 shown in FIG. 4, and rotates a rotation amount corresponding to the paper feed amount instructed by the control means 10. That is, the amount of movement to the position with time is rotated as shown in FIG. At this time,
Since the transmission system such as the motor shaft is stopped in a twisted state,
As soon as the drive current is supplied to the motor 1, a rotational force that overcomes the static friction force is transmitted to the platen 5, and the rotation of the platen 5 starts to feed the sheet. In this break,
Since the paper feed amount is large, all the energy stored by the twist of the transmission system is released during the paper movement. For this reason, as shown in (1), it moves to a position from the position covering the amount of movement between and and stops at the position shown in (2).

Here, the control means 10 causes the printing mechanism 12 to print the next line based on the instruction of the host device 8. That is, a dot row as shown in FIG. 1C is printed. And
In the same manner as described above, the control unit 10 causes the line feed indicated by the host device 8 to be performed and prints a dot line, so that a dot line superimposed on the dot line indicated by is printed, and the print density is doubled as shown in FIG. Is printed.

Note that, for the sake of explanation, the dot rows are divided into rows and displayed.

[Action]

With the configuration described above, the control unit 10 reads out the correction value from the storage unit 11 that previously stores the correction value determined from the static friction force unique to the paper feed mechanism 13, the twist of the motor shaft, the transmission loss of the reduction mechanism, and the like. Therefore, it is possible to correct the paper feed amount of the ideal paper feed mechanism sent from the host device 8, so that the printing apparatus with improved print density can realize economical and accurate paper feed.

Embodiment FIG. 2 is a block diagram of a circuit showing one embodiment of the present invention.

The processor 14 operates by reading the program stored in the ROM 15, and stores the command and the print data transmitted from the host device 8 through the interface circuit 17 in the RAM 16 and then reads out the command. If so, a vector is created based on the coordinate information of the line segment forming the figure, and the figure is drawn in the bitmap memory 19.

When the drawing circuit 18 completes drawing a figure on the bitmap memory 19, the processor 14 causes the reading circuit 20 to perform raster scanning on the bitmap memory 19 via a control line (not shown) to read data.

The readout circuit 20 raster-scans the data in the horizontal direction, rotates the data 90 ° vertically and horizontally, sends it to the head 22 via the head control circuit 21, and outputs the data to the space speed of the carrier 25 and the bitmap memory 19. Each magnet of the head 22 is excited in accordance with a bit representing a continuous line forming a figure.

At the same time, the processor 14 controls the space control circuit 23, drives the space motor 24, moves the carrier 25 at a constant space speed, and moves the head 22 from the home position, for example, in the lateral direction.

When the printing of one line is completed, the processor 14
Based on the print data read from the RAM 16, when it is recognized that the paper feed amount given by the higher-level device 8 is small and the line feed is minute, the correction value stored in advance in the ROM 15 is read, and the paper feed amount specified by the higher-level device 8 is reduced. The correction value is added and sent to the line feed control circuit 26 to drive the motor 1.

Then, the read circuit 20 is controlled to control the bitmap memory.
From 19, the same line of data is read out, and one line is printed in the same manner as described above.

When the processor 14 recognizes that the paper feed amount given by the host device 8 is large and a large line feed based on the print data read from the RAM 16 when the printing is completed, the ROM 1
The correction value stored in advance in 5 is read out, and the correction value is subtracted from the paper feed amount designated by the device 8 and sent to the line feed control circuit 26 to drive the motor 1.

Then, the read circuit 20 is controlled to control the bitmap memory.
From 19, the data of the next line is read, and the printing of one line is performed in the same manner as described above.

By repeating such an operation, a graphic having a high print density as shown in FIG. 1 (c) is printed on the paper with an accurate paper feed amount.

FIG. 3 is a flowchart for explaining the operation of the processor 14 in FIG.

The processor 14 monitors the reception of the print data in steps, and when the print data is sent from the host device 8,
After storing the print data in the RAM 16, the print data is read out and sent to the drawing circuit 18 as drawing data in a step.

Then, in a step, the drawing data is waited until the drawing data has been developed on the bitmap memory, and as described above, the printing of one line is executed in the step. And in step 1
It is checked whether the printing for the page has been completed, and if completed, the process returns to the step.

If it is determined that the paper feed amount indicated by the print data read from the RAM 16 is small and the line feed is minute, the processor
14 is a step which sets RO to the paper feed amount specified by the host device 8.
The correction value read from M15 is added, and a line feed is performed in the step as described above. That is, after a line feed is performed with a small sheet feed amount, the process returns to the step.

If it is determined in the step that the paper feed amount indicated by the print data read from the RAM 16 is large and the line feed is large, the processor 14 subtracts the correction value read from the ROM 15 from the paper feed amount specified by the host device 8 in a step. Then, a line feed is performed in the step as described above. That is, after a line feed is performed with the sheet feed amount up to the next line, the process returns to the step.

Although the above embodiment has been described with respect to a wire dot printer, it can be applied to a dot printer such as a thermal printer or an ink jet printer.

〔The invention's effect〕

As described above, the present invention corrects the disadvantage that the rotation of the line feed motor is reduced before being transmitted to the paper by improving the control method of the processor when the print density is improved by performing the fine line feed. It is possible to execute economically accurate sheet feeding.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, FIG. 3 is a flowchart for explaining the operation of the processor of FIG. 2, and FIG. FIG. 3 is a diagram illustrating an example of a paper feed mechanism. In the figure, 1 is a motor, 2, 3 and 4 are gears, 5 is a platen, 6 is a roller, 7 is a paper, 8 is a host device, 9 is a printing device, 10 is a control device, 11 is a storage device, and 12 is a printing device. Mechanism, 13 is a paper feed mechanism, 14 is a processor, 15 is a ROM, 16 is a RAM, 17 is an interface circuit, 18 is a drawing circuit, 19 is a bitmap memory, 20 is a read circuit, 21 is a head control circuit, 22 is a head, 23 is a space control circuit, 24 is a space motor, 25 is a carrier, and 26 is a line feed control circuit.

Claims (1)

(57) [Claims] 1. A printing mechanism for printing one line by forming dots on a sheet by a plurality of printing elements arranged along the sheet feeding direction while moving in a direction perpendicular to the sheet feeding direction, and a plurality of the same lines. A printing device that controls a paper feed mechanism that executes a fine line feed that feeds a small amount of paper and a large line feed that feeds the paper to the next line when printing multiple times, and performs printing by repeatedly executing the fine line feed and the large line feed. In the above, a predetermined correction value for the paper feed amount is stored, and when the paper feed amount indicates a minute line feed, the paper feed is executed with the paper feed amount obtained by adding the correction value to the paper feed amount, and the paper feed amount is A line feed control method for a printing apparatus, wherein when a large line feed is indicated, a sheet feed is executed at a sheet feed amount obtained by subtracting the correction value from the sheet feed amount.