JPH0644707Y2 - Printer - Google Patents

Description

[Detailed Description of the Invention] [Outline] The present invention relates to a printer, and more particularly to the structure of a medium holding sheet that presses a sheet against a platen, and aims to normalize the sheet feeding during forward / backward printing of uneven sheet. , A platen, a print head that faces the platen with a predetermined gap, and a synthetic resin that presses the edge of the platen in parallel with the platen and presses the paper fed into the gap to the platen at a position close to the print head. In the printer including the medium holding sheet, the medium holding sheet is folded in half and the edge portion is formed in an arc shape.

[Industrial application field]

The present invention relates to a printer, and more particularly, to a structure of a medium holding sheet that presses a sheet against a platen.

2. Description of the Related Art Recently, wire dot printers that form characters and the like based on dots have been put into practical use as printers for terminals of various computers and word processors.

Among them, the serial dot printer has a large number of types of characters and the like because characters and the like are configured by dots and recorded, and the application is expanding more and more as a terminal device in office automation (OA).

There are many types of paper used in these printers, and it is desired that the paper be sent without causing a jam or the like during printing.

[Conventional technology]

As shown in the side view of the main part of FIG. 3, the printer includes a cylindrical platen 1 that can rotate in the forward and reverse directions, and a print head 2 that faces the platen 1 with a predetermined gap (head gap) G therebetween.
And a medium holding sheet 3 that presses the edge portions 3a in parallel in the longitudinal direction of the platen 1 and presses the sheet 4 fed to the gap G.

The medium holding sheet 3 is provided near the lower part of the print head 2 so as to press the paper 4 against the platen 1, and prevents the paper 4 from floating during printing by the print head 2.

The medium holding sheet 3 is made by cutting, for example, a polyester film having a thickness of 0.1 mm, which is excellent in elasticity and abrasion resistance and has physical and chemical stability characteristics.

Printing is performed by moving the print head 2 in parallel along the platen 1 and the paper 4 pressed by the medium holding sheet 3 against the platen 1 via an ink ribbon (not shown).

When printing of one line is completed, the platen 1 is rotated in the forward direction (direction of arrow A), and the mounted paper 4 is fed in the direction of arrow C by a predetermined amount to start a line feed.

[Problems to be solved by the invention]

Printing is performed as described above, but the paper is not limited to one with a smooth surface, but there are folds such as continuous forms, and those with an uneven surface due to perforations.
Further, there is also a paper having irregularities such as so-called tag paper in which label paper is adhered on a mount at a predetermined pitch.

Even with these papers having irregularities on the surface, if the paper is fed in the forward direction as shown in FIG. 3, the media holding sheet does not hinder the feeding.

However, in the case of reverse line feed printing performed by reversing the platen in the direction of arrow B as shown in the same figure, the convex portion of the sheet may be caught on the edge of the medium holding sheet, and a feeding failure may occur.

To prevent this, as shown in the perspective view of FIG. 4, there is a method of bending the edge portion 3a 'of the medium holding sheet 3'outward, but for example, it is extremely difficult to bend the edge portion of a polyester film. There is a problem that it is expensive.

The present invention is intended to normalize the paper feed during forward / reverse printing on paper having irregularities.

[Means for solving problems]

 FIG. 1 is a side view of an essential part of the printer of the present invention.

In the present invention, the platen 1, the print head 2 that faces the platen 1 with a predetermined gap, and the edge 5a of the platen 1 in parallel with each other are pressed against each other to feed the paper 4 fed into the gap. ,
A printer comprising a medium holding sheet 5 which presses against the platen 1 at a position close to the print head 2, wherein the medium holding sheet 5 made of synthetic resin is folded in half and the edge portion 5a is formed in an arc shape. It will be configured.

[Action]

Since the convex portion of the sheet fed back contacts the arc portion, it is not caught and is pressed by the platen by the medium holding sheet.

〔Example〕

 1 and 2 show an embodiment of the present invention.

The same portions are denoted by the same reference numerals throughout the drawings.

As shown in the side view of the main part of FIG. 1, in the present invention, the medium holding sheet 5 made of synthetic resin is folded in two and the edge portion 5a is formed in an arc shape.

That is, as shown in the perspective view of FIG.
For example, a polyester film having a thickness of 0.1 mm is folded in two so that the edge portion 5a has an arc shape.

Then, in order to prevent the folded rear end portion from expanding, the portions are adhered to each other as shown by using a double-sided adhesive tape 6 or the like.

As described above, the edge portion 5a of the folded medium holding sheet 5 is moderately expanded by the restoring force and forms an arc portion.

As shown in FIG. 1, the medium holding sheet 5 is provided in parallel with the platen 1 so that the edge portion 5a thereof approaches the lower portion of the print head 2 and presses the sheet 4 against the platen 1 as in the prior art. .

Printing is performed by moving the print head 2 in parallel along the platen 1 and the paper 4 pressed by the medium holding sheet 5 against the platen 1 via an ink ribbon (not shown).

When the printing of one line is completed, the platen 1 is rotated in the forward direction (direction of arrow A) to feed the paper 4 in the direction of arrow C by a predetermined amount for line feed. In the case of reverse line feed printing, the platen is moved in the direction of arrow B. And the sheet 4 is fed backward.

In this way, the paper 4 is transferred in both the forward and reverse directions due to line feeds. However, even if the surface of the paper 4 has irregularities during the transfer, if the feed direction is the forward direction, it is of course the reverse direction. Even in this case, the convex portion of the sheet 4 does not get caught because it abuts the circular arc portion 5a of the medium holding sheet 5.

As described above, the sheet 4 is pressed by the platen 1 by the medium holding sheet 5 and is normally transferred in both the forward and reverse directions.
High-quality printing is performed according to.

[Effect of device]

As described above, according to the printer of the present invention, even if the paper has irregularities on the surface, it is pressed by the platen by the medium holding sheet to be normally transferred in both the forward and reverse directions, and the floating of the paper is prevented. It has great economic and industrial effects such as high-quality printing.

[Brief description of drawings]

FIG. 1 is a side view of an essential part of a printer of the present invention, FIG. 2 is a perspective view of a medium holding sheet applied to the printer of the present invention, FIG. 3 is a side view of an essential part of a conventional printer, and FIG. FIG. 6 is a perspective view showing an example of a medium holding sheet applied to the printer of FIG. In the figure, 1 is a platen, 2 is a print head, 3 and 5 are medium holding sheets, 3a and 5a are edge portions, and 4 is paper.

Claims (1)

[Scope of utility model registration request] 1. A platen (1), a print head (2) facing the platen (1) with a predetermined gap, and an edge portion (5a) pressed against the platen (1) in parallel. ,
A printer comprising: a medium pressing sheet (5) for pressing a sheet (4) fed into the gap against the platen (1) at a position close to the print head (2); A printer characterized in that the medium holding sheet (5) is folded in two and the edge portion (5a) is formed in an arc shape.