JPH0449071A - Printer - Google Patents

Abstract

PURPOSE:To extend the life of a platen roll by preventing that printing pressure is repeatedly applied only to the same place by a method wherein the position on the surface of the platen roll exactly opposed to a printing head is allowed to coincide with the position before one revolution when the platen roll makes one revolution by line feed operation. CONSTITUTION:Line feed operation is carried out by controlling the rotation of a paper feed motor 26 by a line feed control part 40 and a pin belt tractor 2 is driven so as to set a line feed pitch to a constant pitch of 1/6 inch, for instance. A platen roll 3 is rotationally driven in a 1% over-feed state in connection with the line feed operation. Therefore, when the platen roll 3 makes one revolution by the line feed operation corresponding to 27 lines, the outer peripheral surface of the platen roll 3 is excessively rotated by 1% of a 27-line feed pitch, that is, a 0.27-line feed pitch. As a result, the printing pressure applied to the platen roll 3 from a printing head 1 is applied to different positions on the outer peripheral surface of the platen roll 3 at each time when the platen roll 3 is rotated but not repeatedly applied to the same place.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printer used for printing computer output data.

Generally, a printer is provided with a platen roll that is rotationally driven in conjunction with a feed change operation. This platen roll is provided so as to be in contact with the back surface of the printing paper at a position facing the print head, and receives printing pressure from the print head from the front.

[Conventional technology]

Generally, the length of the outer circumference of the platen roll is formed to be an integral multiple of the line feed pitch of the printer. Most commonly, the outer circumferential length of the platen roll is set to be equal to 27 line breaks.

Further, the peripheral speed of the platen roll is generally set to be the same as the paper feeding speed.

[Problem to be solved by the invention]

As mentioned above, if the outer circumferential length of the platen roll is an integral multiple of the line feed pitch of the printer, and the circumferential speed of the platen roll is the same as the paper feed speed, the platen roll
When rotated, the position on the platen roll surface that directly faces the print head matches the position one rotation before, and the same position on the outer peripheral surface of the platen roll receives printing pressure from the print head.

Therefore, the platen roll receives printing pressure repeatedly at the same location each time it rotates, and in printers that use high printing pressure such as impact dot print heads,
A dent occurs early on the outer peripheral surface of the platen roll, making it impossible to perform normal printing. In this case, the platen roll has reached the end of its service life.

In this way, in conventional printers.

There is a drawback that the life of the platen roll runs out relatively early and the platen roll must be replaced frequently.

The purpose of this invention is to provide a printer that can eliminate such conventional drawbacks and extend the life of the platen roll by preventing repeated printing pressure from being applied only to the same location on the outer peripheral surface of the platen roll. shall be.

Directly facing Sodo I.

[Means to solve the problem]

In order to achieve the above object, the printer of the present invention has a printing paper 100 facing the print head l so that printing is performed at a predetermined line feed pitch, as shown in the diagram for explaining the embodiment. A printer comprising a line feed means 2 for line feed, and a platen roll 3 that is provided so as to be in contact with the back surface of the printing paper 100 at a position facing the print head l and is rotationally driven in conjunction with the line feed operation. The apparatus is characterized in that when the platen roll 3 rotates once due to the changeover operation, the position on the surface of the platen roll 3 directly facing the print head l does not match the position before one rotation.

[Effect]

When the platen roll 3 makes one revolution due to the changeover operation, the platen roll 3 prints at a position different from the position directly facing the print head l when it made one revolution before. [Example] Referring to the drawings, the printer of the example Explain.

In the figure, l is a print head, for example, an impact dot type print head is used.

2 is a pin belt tractor for feeding the printing paper 100 of continuous forms to a position facing the print head 1; 2
Reference numerals 1 and 22 are first and second paper feed rollers provided in pairs before and after the print head I, respectively.

23 and 24 are the first and second paper feed rollers 21,
First and second driven pulleys rotate together with 22. 25
is a driving pulley rotationally driven by the paper feed motor 26.

The two driven pulleys 23 and 24 and the driving pulley 25 include
- A book timing belt 27 is stretched around the book, and the first and second paper feed rollers 21, 22 are rotationally driven by a paper feed motor 26 via this timing belt 27 and each pulley 25, 23, 24.

All the parts indicated by broken lines in the figure are gears, and the pin belt 29 of the pin belt tractor 2 is Rotationally driven.

This printer can also use single-sheet printing paper, but when using continuous form printing paper 100, the first
The paper feed roller 21 is in an oven state. Then, the pin belt 29 engages with the paper feed hole of the continuous form printing paper 100, and the printing paper 100 sandwiched between the second paper feed rollers 22 is transferred to the print head l by the pin belt tractor 2 and the second paper feed roller 22. Paper is fed in opposite directions.

However, the amount of paper feed is determined by the amount of movement of the pin belt 29, and the amount of rotation of the paper feed roller 22 overfeeds the printing paper 100 by, for example, about 0.3% compared to the amount of paper feed by the pin belt tractor 2. It is set. Therefore, a very slight amount of slippage occurs between the paper feed roller 22 and the printing paper 100.

A cylindrical platen roll 3 is rotatably arranged at a position facing the print head 1 so as to be in contact with the back surface of the print paper 100. This platen roll 3 is rotationally driven in the direction of arrow R by a paper feed motor 26 via a gear 32 that rotates together with the second paper feed roller 22 .

The outer circumferential length of the platen roll 3 is set to exactly 27 line feeds, as in the conventional case.

However, the platen roll 3 is set to a rotation amount that overfeeds the printing paper 100 by, for example, about 1% compared to the paper feeding amount of the pin belt tractor 2, so that slipping occurs between the platen roll 3 and the back side of the printing paper 100. ing.

In the printer configured in this manner, the line feed control unit 40 controls the rotation of the paper feed motor 26 to perform the line feed operation so that the line feed pitch is a constant pitch of, for example, 1/6 inch (4.23 m+). Then, the pin belt tractor 2 is driven. As described above, the platen roll 3 is rotated in a 1% overfeed state in conjunction with the changeover operation.

Therefore, when the platen roll 3 rotates once due to the line feed operation for 27 line feeds, the outer circumferential surface of the platen roll 3 rotates an extra 1% of the 27 line feed pitch, that is, 0° by the 27 line feed pitch. In other words, the platen roll 3 moves from the position directly facing the print head l to 0 before one revolution.
．． It directly faces the print head 1 at a position shifted by 27 line feed pitches.

As a result, the printing pressure applied from the print head 1 to the platen roll 3 is applied to different positions on the outer peripheral surface of the platen roll 3 each time the platen roll 3 rotates.

Note that the present invention is not limited to the above embodiments,
For example, the platen roll 3 may be fed too little, or the outer periphery of the platen roll 3 may be formed to have a length different from an integral multiple of the line feed pitch, and the rotation of the platen roll 3 may be made to match the paper feed amount.

〔Effect of the invention〕

According to the printer of the present invention, since the printing pressure from the print head is not repeatedly applied to the same location on the platen roll, irregular dents do not occur on the platen roll, and the life of the platen roll is significantly extended compared to conventional ones. It has an excellent long-lasting effect.

[Brief explanation of the drawing]

The figure is a schematic side view of the embodiment. In the figure, 1... Print head, 2... Pin belt tractor (line feed means), 3... Platen roll, 100... Print paper.

Claims (1)

[Claims] The print head (
a line feed means (2) for line-feeding the print paper (100) facing the print head (1);
a platen roll (3) that is provided so as to be in contact with the back surface of the printer (100) and is rotationally driven in conjunction with the changing action, when the platen roll (3) rotates once due to the changing action. A printer characterized in that the position on the surface of the platen roll (3) directly facing the print head (1) does not match the position one rotation before.