JPH0367035B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feeding device in a dot line printer capable of high-speed printing and used as an output device of a data processing device such as a computer, word processor, or drawing machine.

In an impact-type dot line printer, generally, as shown in FIG. 1, a platen 1 and a printing head (shuttle head) 2 are arranged facing each other, and a paper feed tractor 4 passes printing paper 3 between them so as to be in close contact with the platen 1. The material is intermittently conveyed in the direction of arrow A.

On the other hand, the printing head 2 has a plurality of printing needles 5 (for example, 44) arranged in a direction perpendicular to the conveying direction of the printing paper 3 (in FIG. 1, a direction perpendicular to the paper surface). While the head 2 is continuously oscillated back and forth in the direction in which the printing needles 5 are arranged with a width slightly exceeding the arrangement interval, each of the plurality of printing needles 5 is driven by an electromagnetic solenoid (not shown) to print the ink ribbon 6. Characters, figures, etc. are printed by selectively colliding with the printing paper 3 through the printing paper 3.

In FIG. 1, the paper feed tractor 4 includes a timing belt 41 having a row of protrusions 41a that engage with perforations formed along both side edges of the printing paper 3, and a timing belt 41.
A driving pulley 42 and a driven pulley 43 tensioning the
and a paper presser 44, and the drive pulley 42 is rotated step by step by a stepping motor (not shown).

Further, 7 is a paper presser made of a spring plate for applying back tension to prevent the printing paper from sagging.

According to such a dot line printer, each printing stylus 5 of the printing head 2 divides a plurality of characters into a matrix of 9 horizontal by 7 vertical, for example, as shown in FIG. Printing is performed in both directions of reciprocating swing as shown by the arrow, and in this example,
3.5 Complete multiple letters while going back and forth.

Therefore, since the swing width of the printing head is small, it can be oscillated at high speed, and moreover, a large number of characters can be printed at once using a plurality of printing needles, making it suitable for high-speed printing.

However, when starting printing in such a dot line printer or restarting printing after interruption, it is impossible to immediately swing the print head 2 at a predetermined high speed and start printing due to inertia.

Therefore, the print head starts swinging before the actual printing operation, and prints after entering a standby state where it swings back and forth at a predetermined speed, and the print head does not stop swinging even when printing is temporarily interrupted. Now, I am preparing to resume printing.

By the way, before the start of printing and during standby due to interruption of printing, the paper feed tractor 4 shown in FIG. 1 is stopped and the printing paper 3 should not move.
In reality, the vibrations caused by the high-speed rocking of the print head 2 are transmitted to the print paper 3 via a ribbon mask (not shown), etc., and act to push the print paper 3 up slightly in the direction of arrow A, causing the print paper 3 to move as shown in the hypothetical diagram in FIG. A sagging phenomenon occurs as shown by the line.

Therefore, even if printing is started after that and the paper feed tractor 4 is driven, the first few pitches only make the slack of the printing paper 3 tense, and the printing paper 3 can hardly be fed at the printing position. The printing needle 5 strikes several dots at almost the same position on the printing paper 3 in the paper feed direction, and when printing is started or resumed, the characters in the first line are flattened at the top, as shown in Figure 3. I had the problem of getting used to it.

In order to solve this problem, when printing is started or interrupted, the printing paper is fed by the space between the lines, and then the printing operation is started.
Not only will the printing start position shift, but if there is a character "y" in the line before the interruption, there will not be enough space between the lines, and in the case of a heart mark, there will be no space between the lines at all, so this method cannot be used. .

In order to prevent the printing paper 3 from sagging, it has been considered to strengthen the back tension using the paper presser foot 7 shown in FIG. A problem arises in that the load on the ping motor increases, making it impossible to smoothly convey the printing paper.

This invention was made in order to solve all of the above-mentioned problems in dot line printers.

That is, in the paper feeding method of the dot line printer according to the present invention, the force pushing up the printing paper due to the swinging of the print head during standby is not very large, so that the printing paper does not move as shown by the imaginary line in FIG. When the printing paper 3 slackens to a certain extent, it is balanced with the force pushing it back in the direction of arrow B due to the rigidity of the printing paper 3, and the printing paper 3 no longer slackens. To provide slack in advance between the platen 1 and the paper feed tractor 4 by returning it in the opposite direction by a predetermined amount, and then, just before starting or resuming printing, feed the printing paper by the amount returned earlier to create tension. To achieve the above objectives.

FIG. 4 is a block diagram of a dot line printer embodying the present invention. This dot line printer 10 inputs print data from a computer 9 to an input buffer 12 via an interface 11, and inputs it to a microprocessor. A control unit 13 using a computer sequentially reads and prints the data.

This control section 13 outputs a signal to a stepping motor driver 14 to control the rotation of a stepping motor 15 that drives the paper feed tractor 4 shown in FIG. 1, and outputs a signal to a stepping motor driver 16. to control the reciprocating movement of the printing head 2 by the head feeding stepping motor 17,
A signal is output to the solenoid driver 18 to selectively drive each printing stylus 5 by a plurality of electromagnetic solenoids provided in the printing head 2.

Since such control is similar to that of a normal dot line printer, detailed explanation will be omitted.

By the way, this control section 13 performs paper feeding control as shown in FIG. 5 in order to implement the present invention.

When the print head 2 starts to swing, it is first determined whether printing is interrupted (or on standby), and if NO, printing is in progress, so one dot is printed (in this case, including the space due to print data), Perform normal paper feeding by feeding the printing paper one pitch.

Then, it is determined whether printing has ended or not, and if the printing has ended, the printing head is stopped, but if not, the above operation is repeated again to print characters, figures, etc.

If the judgment for printing interruption (or standby) is YES,
The paper feeding stepping motor 15 is reversed to reverse the paper feeding tractor, and the printing paper 3 shown in FIG. 1 is returned by a predetermined amount (n pitches) in a direction opposite to the normal feeding direction (direction of arrow B).

Immediately before printing is started or resumed, the paper feeding stepping motor 15 is rotated in the normal direction, the paper feeding tractor 4 is rotated in the normal direction, and the printing paper 3 is transferred by a predetermined amount (n pitches) in the normal feeding direction ( direction of arrow A)
After the first dot is printed, the paper is fed normally one pitch at a time.

Whether printing is interrupted or not and whether printing is to be resumed can be determined based on whether or not the input buffer 12 has print data for the next dot (including space data such as line spacing). That is, if there is no print data for the next dot during printing, printing is interrupted, and if print data arrives after the interruption, printing is resumed. Note that if the printer is for text only, this determination may be made for each line of text.

Waiting can be determined when the printing head starts swinging from a stopped state, and printing start can be determined by a printing start command after waiting.

Note that if the printing interruption state continues for a preset time or more, it is determined that printing has ended.

The amount by which the printing paper is returned is selected so as to provide for the maximum amount of slack in the printing paper that would occur if the printing head continued to swing without feeding the printing paper. Since this varies depending on the thickness of the printing paper, the strength of the back tension, etc., it is preferable to be able to adjust it within a range of about 1 to 12 pitches.

According to the results of experiments, in the case of a character with 7 dots vertically and 5 dots in the space, it was good to move back by 5 to 10 dots.

By feeding the paper in this way, printing can be started or resumed with the printing paper always under tension, so the upper part of the characters in the first line will not be crushed as shown in Figure 3, and the printing will be done evenly. You can obtain high printing quality.

The present invention is not limited to a 9x7 dot alphanumeric printer, but can also be applied to a 24x24 dot kanji printer and various other dot line printers for characters or graphics.

As explained above, according to the present invention, it is possible to completely eliminate the problem of print quality deterioration caused by sagging of printing paper when printing is started in a dot line printer and when printing is restarted after printing is interrupted.
Can handle any type of print data. Further, since there is no need to strengthen the back tension or add any special mechanism, the present invention can be implemented immediately in conventional dot line printers.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the mechanical structure of a dot line printer to which the present invention is applied, FIG. 2 is an explanatory diagram showing an example of the dot configuration of characters printed by the dot line printer, and FIG. , is also an explanatory diagram of the printing state of the first line character due to the start or restart of printing, FIG. 4 is a block diagram of a dot line printer implementing the present invention, and FIG. 5 is a diagram showing the paper feed by the control unit. It is a flow diagram of control. 1...Platen, 2...Print head, 3...Print paper, 4...Paper feed tractor, 5...Print needle, 6...Ink ribbon, 7...Paper presser, 10...Dot line printer, 13...Control unit, 15...Paper feed stepping motor.

Claims (1)

[Claims] 1. Print paper is conveyed in close contact with a platen by a paper feed tractor, and a print head having a plurality of printing needles arranged in a direction perpendicular to the conveyance direction is opposed to the platen. and place it,
By selectively colliding the plurality of printing needles with the printing paper via the ink ribbon while continuously swinging the printing needles back and forth in the arrangement direction of the printing needles,
In a paper feeding method for a dot line printer that prints characters, figures, etc., during printing standby or interruption, the paper feeding tractor is reversed, the printing paper is returned by a predetermined amount in the opposite direction to the normal feeding direction, and the printing paper is moved back to the platen. and a paper feed tractor to give slack to the printing paper,
A paper feeding method comprising: rotating the paper feeding tractor in the normal direction immediately before starting or resuming printing, and feeding the printing paper by the predetermined amount to tension it.