JPS5820478A - Smudge preventing device for printer - Google Patents

Abstract

PURPOSE:To obtain a compact smudge preventing mask, in a ink applying type printer, by engaging a positioning member comprising a material whose linear expanding coefficient is different from that of a frame with the smudge preventing mask which is supported on the frame by a shaft. CONSTITUTION:The smudge preventing mask 6 has the tips which form comb teeth shaped smudge preventing parts 6a and the parts are positioned in the grooves between type rings 2a-2a of a type dum 2. Bent parts 6b at the lower end are rotatably supported by supporting parts 1a of the frame 1. The mask positioning member 7 comprising e.g. a plastic material whose expansion coefficient is larger than that of the frame 1 is engaged with the top of the bent part 6b through a pin 8. The other end of the positioning member 7 is fixed to the frame 1. When the temperature is increased, the member is elongated and operated so that the smudge preventing part 6a of the mask 6 is separated from the type drum 2, and the increase in the quantity of the ink applied to the type drum 2 from an ink roll 3 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stain prevention device for an ink coating type printer that compensates for print density based on temperature changes.

In general, in ink-applying type printers, there is a stain-preventing mask provided in contact with the outer periphery of the type drum to compensate for print shading due to temperature.

In other words, non-uniform print density of the printer is caused by the printer device 1
This is a factor that directly affects tVc, and various research and development efforts have been made on how to compensate for the 6-tone effect of printing. It is well known that the problem can be easily solved by linking bimetals that act based on temperature changes.

However, when attaching a bimetal to a printer mechanism, structurally complex parts cannot necessarily be assembled into a conopact structure, which increases the cost of the printer itself, making it difficult to form the printer at a low cost.

The present invention addresses problem 1 (@) described in -, and fixes a mask positioning system made of a material with a coefficient of linear expansion different from that of the frame to the dirt-preventing mask that is pivotally supported on the frame. By doing so, the smudge prevention mask is indirectly oscillated in response to temperature changes to compensate for the a-lightness of the print. An example will be explained based on FIG.

FIG. 1 shows a retaining portion of a printing smear prevention device for an ink coating type printer, and in the figure, 1 is a frame made of a metal material. A type drum 2 is arranged above the frame 1 so as to roll with an ink-coated ink roll 3.

A sheet of paper 4 is arranged in front of the type drum 2, and a plurality of arranged stamping huffs 7-5 are configured to press the sheet of paper 4 into desired type rings 2a, 2b, 2c, and 2d (-).

In the above printing mechanism, a dirt prevention device is installed in the limited space between the paper and the type drum by installing a dirt prevention mask 6 and a mask positioning member r, which can be easily configured.
t, it's something.

That is, the stain prevention mask 6 has an approximately comb-shaped stain prevention part 6a whose tip can be positioned in the groove provided between the type rings 2a, 2b, 2c, and 2d of the type drum 2, It has a plate shape with a bent portion 6b bent at the bottom.

The lower end of this bent portion 6b is rotatably supported by a support portion 1a that partially protrudes from the frame 1. In addition, the force of the bending portion 61 is made of a material different from the material of the frame 1, one end of which is fixed to the frame 1, for example, a plastic material with a large linear expansion coefficient 1. The other end of part 7 will be connected through pin 8 with parts 1 to 1, so it will get dirty.1. Defense 111. Mask 6 is F1/-F1"
- The temperature changes with the support portion 1a as a fulcrum (positioned so as to be swingable from C).

That is, when the crystallinity increases by -(2), for example, the mask positioning member 1, which is larger than the expansion 1 series of the gold frame 1, stretches and separates from the type drum 2. Inocroll 3 or ``) prevents the increase of ick coating on the type drum 2 and controls the density of the print.Also, when the temperature drops to below 0, the mask positioning member γ contracts and the smudge prevention mask 6 is activated. The anti-fouling portion 6a is again close to the type drum 2.

And the type drum 2's type drum 2a, 2b, 2c, 2
(d) It does not act like applying ink at a constant rate.

Next, another embodiment of the present invention will be described with reference to FIG.

FIG. 2 is a side view of a main part of the stain prevention device of the printer, and the upper end of the bent portion 16b of the stain prevention mask 16 is pivotally supported by a support portion 11a formed by bending the metal frame 11.

and a mask positioning member I made of plastic material.
has one end on the metal frame 11 and the other end on the bent part +6
It is locked to the lower end of b via pinot 8.

The spacing between the locking points between the support portion 11a and the pin 8 of the mask positioning member 11 can be set arbitrarily, but depending on the distance l, the movement of the tip stain prevention portion 16a of the stain prevention mask 16 increases by 1 degree. will change, expand, and be displaced.

5 +C1 In this embodiment, the stain prevention device has a structure in which the fulcrum position of the metal frame 11 with respect to the mask positioning part 11 is reversed in the arrangement of the stain prevention mask 16 compared to the embodiment shown in FIG. .

Therefore, when compensating for printing shading according to temperature changes, dirt J
The ic density on the type drum 2 can be controlled by the swinging displacement of the 1-prevention mask 16.

Furthermore, the material relationship between the metal frame 11, the dirt prevention mask 16, and the mask positioning member 11 made of plastic material can be reversed, and in that case, the fulcrum positional relationship in the configurations shown in FIGS. 1 and 2 can be reversed. do it.

As described above, in the present invention, a mask positioning member made of a material with a coefficient of linear expansion different from that of the frame is disposed in order to swing and displace the stain prevention mask in response to temperature changes, thereby compensating for the darkness of printing. The application effect as a dirt prevention device for printers is amazing.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part of a dirt prevention device for a printer showing an embodiment of the present invention, and FIG. 2 is a partial side view showing a modification of FIG. 1. 1.11...Metal frame, 2...Type drum, 3.
・・Ink roll, 6.16・・Stain prevention mask, 6
a, t 6 a-stain prevention part, 6b, I 6 b...
・Bending portion, 7.17...Mask positioning member. Patent applicant Citizen Watch Co., Ltd.

Claims (1)

[Scope of Claims] In a printer in which ink is applied by hitting paper with a hammer and the paper is partially immersed in a type drum to perform desired printing, dirt is applied to the gaps between the type characters on the type drum. 1
A stain-preventing stain-proof cloth having a comb-shaped stain-preventing part and having a lower end pivoted on a frame, and a material having a linear expansion coefficient different from that of the frame, and one end fixed to the frame. and a mask positioning member whose other end is locked to a part of the stain prevention mask.