JPS634981A - Paper-feeding mechanism for printer - Google Patents

Abstract

PURPOSE:To provide a paper-feeding mechanism for a printer by which a paper feed pitch for a printing paper can be easily changed, by controlling the paper feed pitch for the printing paper by regulating the number of pulses outputted to a pulse motor. CONSTITUTION:A paper-feeding mechanism 11 comprises a platen 12 disposed in the vicinity of a thermal-type head 7 provided with a shift register 8, a latch and driving circuit 9 and a head element group 10. A rotary shaft 12a of the platen 12 is connected to the output side of a gear mechanism 14, the input side of which is connected to a rotary shaft 15a of a pulse motor 15 and which outputs the rotation of the motor 15 by reducing the speed by a fixed ratio. A discriminating means in a controller 2 discriminates the system of a video signal previously inputted, and based on the result of discrimination, the controller 2 outputs four or five pulses to the motor 15. The pulse motor 15 is rotated by a predetermined angle according to the number of the pulses, and the rotation is transmitted to the platen 12 through the gear mechanism 14, whereby a printing paper 13 is fed by a predetermined pitch.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding mechanism for a printer that feeds printed paper at a partial pitch during printing.

[Summary of the Invention] The present invention provides a paper feeding mechanism for a printer in which printing paper is fed by driving a pulse motor, in which the paper feeding pitch of the printing paper is varied by increasing or decreasing the number of pulses applied to the pulse motor. This allows the paper feed pitch to be easily varied.

[Prior Art] For example, a video printer that can print out not only characters but also images handles various video signals such as the NTSC system and the PAL system. Since the number of dots in the vertical direction (the number of scanning lines in the horizontal direction) within one screen differs in such video signals, it is necessary to change the paper feed pitch amount of the print paper.

Further, it is also necessary to change the paper feed pitch amount when enlarging and printing out a part of the television reception screen, or when reducing and printing out all or part of the television reception screen.

As shown in FIG. 3, in the paper feed mechanism 11 of a conventional printer, a thermal spatula 7 and a platen 12 are arranged close to each other, and a print paper 13 is placed between the head 7 and the platen 12. It has been inserted.

The rotating shaft 12a of the platen 12 is connected to the output side of a gear mechanism 14, and the rotating shaft 15a of a pulse motor 15 is connected to the input side of the gear mechanism 14.

This pulse motor 15 rotates by a constant angle by a motor drive pulse from a controller (not shown).

Then, when one horizontal line is printed,
A controller (not shown) sends one pulse to pulse motor 1.
Output to 5. Then, the pulse motor 15 rotates by a certain angle, and this movement is reduced by a certain ratio by the gear mechanism 14 and transmitted to the platen 12. The platen 12 rotates by a certain angle, and the print paper 13 moves by a certain pitch. By repeating this operation, the print paper 13 is fed.

When changing the feed pitch amount of the print paper 13, the gear box constituting the gear mechanism 14 may be replaced,
Also, this has been done by changing the gears constituting the gear mechanism 14 and varying the gear ratio.

[Problems to be Solved by the Invention] However, in the paper feeding mechanism 11 described above, it is necessary to change the gear box and the gears in the gear box, so changing the feeding pitch amount of the printing paper 13 is troublesome. There were drawbacks.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a paper feeding mechanism for a printer that can easily change the paper feeding pitch amount of printed paper.

Means for Solving Problem E] - The configuration of the present invention for achieving the object described above is based on a paper feeding mechanism of a printer that uses a pulse motor to feed the printed paper during printing. The paper feed pitch amount is varied by increasing or decreasing the number of pulses output to the pulse motor.

[Function] Therefore, the desired paper feed pitch amount can be obtained by changing the number of pulses output to the pulse motor (=4-), and the desired paper feed pitch amount can be easily obtained without changing the gear ratio. can be obtained.

[Example] Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, an A-D converter 1 converts an input video signal into 5-bit gradation data based on a reference clock supplied from a controller 2, and outputs the data to a frame memory 3.

This frame memory 3 has a memory corresponding to a print image A of 640 dots in the horizontal direction x 625 dots in the vertical direction, and can store tone data (1 dot - 5 bits) of the entire print image A. The frame memory 3 sends 1942 gradation data in the horizontal direction to the line memory 4 based on the address signal from the controller 2.

This line memory 4 temporarily stores 1942 gradation data in the horizontal direction of the frame memory 3, and 64 gradation data from the 1st dot according to the address signal from the controller 2.
The stored contents of each 5 bits up to the 0th dot are sequentially output to the comparator 5 in parallel.

In this line memory 4! When printing of a line is completed, the tone data for the next line is transferred from the frame memory 3 and the tone data is updated.

The gradation counter 6 sequentially outputs reference gradations from the first gradation to the 32nd gradation to the comparator 5 under the control of the controller 2 .

This comparator 5 sequentially compares the gradation data from the line memory 4 with the reference gradation sent from the gradation counter 6 from the 1st gradation opening to the 32nd gradation, and the gradation data When the gradation data is greater than or equal to the reference gradation, an H signal is output, and when the gradation data is smaller than the reference gradation, the 7 signal is serially output to the shift register 8 of the head 7 as data.

This shift register 8 has 640 head elements T +
It has a storage capacity that can store drive/non-drive information (H signal for drive, I7 signal for non-drive) of each of T1-1 to Tl-640, and converts the data sent from the comparator 5.
It is stored in a predetermined location using the shift clock from roller 2.

The latch and 1941 circuit 9 is connected to the switch I from the controller 2.
- When the lobe signal is input manually, the storage state of the noft register 8 is latched during that period.

The eight l-element group 10 includes 640 head elements Tl1l.
~ Tl Toro 40 is arranged in parallel, and the latch and 1941
It is driven or non-driven depending on the latch state of the circuit 9.

The paper feed mechanism 11 includes the shift register 8, the latch and drive circuit 9, and a head element group 10. A platen 12 is arranged near the thermal head 7. Thermal paper, which is print paper 13, is inserted.

The outer periphery of the platen 12 is made of a high-friction member such as rubber, and the print paper 13 moves as the platen 12 rotates.

A rotating shaft 12a of this platen 12 is connected to the output side of a gear mechanism 14.

The input side of this gear mechanism 14 is connected to the rotating shaft 15a of the pulse motor 15, and outputs the rotation of the pulse motor 15 after decelerating the rotation by a certain ratio. The reduction ratio of the gear mechanism 14 is determined depending on how many types of paper feeding pitches of the print paper 13 are required and their sizes, and will be described in detail below.

The pulse motor 15 rotates at a fixed angle in response to one input pulse, and the pulse for driving the pulse motor 15 is supplied from the controller 2.

As described above, this controller 2 performs operations such as outputting a reference clock to the A-D converter 1 and sending an address signal to the frame memory 2, as well as outputting a predetermined number of pulses to the pulse motor 15. do.

The number of pulses output by the controller 2 is determined in the same way as determining the reduction ratio of the gear mechanism 14. How many different paper feeding pitch patterns of the paper 13 are required and how large are the patterns? The method of determining the number of pulses will be explained together with the method of determining the reduction ratio of the gear mechanism 14.

For example, if video signals of three formats, A format and B format are used, the vertical length (I7) of the print image A in the three video signals is the same, and the number of vertical dots (-
The case where the number of lines in the horizontal direction is 625 dots in method A and 525 dots in method B is shown.

For method A, the paper feed pitch amount (12A) is 0, A
= 1. , / 625 ・■.

For method B, the paper feed pitch amount (ρB) is ρo =
It becomes L/525.

The ratio of this pitch amount is aA, θB=L/625:L/525.

If this is a ratio of approximately integers, then QA:ρB=4・5 becomes. That is, it is the reciprocal of the ratio of both numbers of dots.

Here, if the moving length of the print paper 13 that is moved by l pulse is p, it is sufficient that 4p-ρA, 5p=(!e...■).

Therefore, as shown in Figure 2, if 4 pulses are given for method A and 5 pulses are given for method B, the paper will be fed by the respective predetermined feed pitch amounts (f!A, f!s). It turns out.

- On the other hand, the moving length p) of the printing paper 13 that moves with one pulse is p - (L/625) x (1/4) from the equations (1) and (2).

The reduction ratio of the gear mechanism 14 may be determined so that the value of p is achieved.

In addition, the number of pulses is an integral multiple of the pulse ratio (4n, 5n;
n may be an integer). In this case, the moving length p) of the print paper 13 that moves in one pulse is 1/n of the above value.
shall be.

The controller 2 is provided with a determining means for determining the format of the video signal, and controls output pulses based on the determination result of the determining means. Further, a switch for setting the number of pulses may be provided and the output pulses may be controlled by the operating position of this switch.

The operation of the -J2 printer will be explained below.

The input video signal is converted into 5-bit gradation data by an A-D converter 1, and information for one screen is stored in a frame memory 3.

Information for one horizontal line is transferred from the frame memory 3 to the line memory 4, and is sequentially sent to the comparator 5 from the 1st horizontal dot to the 640th dot in accordance with the address signal from the controller 2.

The comparator 5 uses this gradation data and 1 from the gradation counter 6.
It is compared with the standard gradation of the gradation, and the result is output to the shift register 8.

When all 640 pieces of data are transferred to the shift register 8, a strobe signal is output to the latch and drive circuit 9, and the latch and drive circuit 9 latches the data by the pulse width of the strobe signal and transfers the data to a predetermined head element TH-1. ~
Tl-640 generates heat.

At the falling edge of the strobe signal, the line memory 4
The gradation data is read out again and this gradation data is sent to the comparator 5.
It is compared with the reference gradation of the second gradation of the gradation counter 6, and the result is sent to the shift register 8, where the same operation as described above is performed. When this operation is completed up to 32 gradations, printing out for one line in the horizontal direction is completed, and the inside of the line memory 4 is updated with the gradation data of the next line.

Further, the determining means in the controller 2 determines the format of the manually input video signal in advance, and the controller 2 outputs four or five pulses to the pulse motor 15 based on the result of this determination.

The pulse motor 15 rotates at a certain angle according to the number of pulses, and this rotation is transmitted to the platen 12 via the gear mechanism 14.
The print paper 13 is fed by a predetermined pitch amount (12A or NB).

Then, when printing of one line and feeding of the printing paper 13 are completed 625 or 525 times, printing of one screen is completed.

In this embodiment, a case has been described in which the paper feed pitch amount of the print paper 13 is varied for video signals of different formats, but it is also possible to enlarge a part of the television reception screen or reduce all or part of the television reception screen. The present invention can be similarly applied when changing the paper feed pitch amount of the print paper 13 in cases where the paper feed pitch amount of the print paper 13 is varied.

Furthermore, in this embodiment, the case of a so-called line printer and a thermal printer was shown, but
It is not limited to this.

[Effects of the Invention] As described above, according to the present invention, the paper feed pitch amount of the print paper is varied by increasing or decreasing the number of pulses output to the pulse motor, so it is no longer necessary to take troublesome measures such as changing the gear ratio. This has the effect that the paper feed pitch amount can be varied by a simple means of increasing or decreasing the number of pulses to the pulse motor without having to do so.

In addition, in the past, it was difficult for the user to change the paper feed pitch amount in order to change the gear ratio, but with the present invention, the user can simply add a configuration such as installing a switch for setting the number of pulses. You can easily change the amount of paper feed pitch.

Furthermore, since the paper feed pitch amount is varied by increasing or decreasing the number of pulses to the pulse motor, and generally a plurality of pulses are used, an accurate paper feed pitch amount can be obtained.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, FIG. 1 is a block diagram of a head drive control circuit, FIG. 2 is a diagram explaining the relationship between the number of pulses and the feed pitch amount, and FIG. The figure is a perspective view of a conventional paper feeding mechanism. 11...Paper feed mechanism, 13...Print paper, 15.
・・・ノ(Rusmoke. A no Hi no 2 de ° Oi sengo's long inclination s2 to ゛ no 2゛ de (A color name i) Procedural amendment (voluntary) September 17, 1985

Claims (1)

[Scope of Claims] In a paper feeding mechanism of a printer in which printing paper is fed by driving a pulse motor during printing, the paper feeding pitch amount of the printing paper is variable by increasing or decreasing the number of pulses output to the pulse motor. A printer paper feed mechanism characterized by: