JP2578813B2 - Printing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a printing device.

2. Description of the Related Art Conventionally, in a printing apparatus, a sheet called a back tension plate presses the sheet against a platen in order to prevent the sheet from rising before reaching a printing unit.

FIG. 3 is a side view of a main part of a conventional printing apparatus, wherein 1 is a printing paper, 2 is a platen for supporting the printing paper 1 from the back,
Reference numeral 3 denotes a print head for printing on the printing paper 1, 4 denotes a carriage on which the print head 3 is mounted, 5 denotes a carriage shaft for guiding the carriage 4, and the carriage 4 is guided by the carriage shaft 5 and moves along the platen 2. Has been enabled. Reference numeral 6 denotes a back tension plate for pressing the printing paper 1 against the platen 2, and reference numeral 7 denotes a spring for urging the back tension plate 6 toward the platen 2.

The operation of the conventional printing apparatus configured as described above will be described below.

First, the print sheet 1 is set so that it does not loosen between the platen 2 and the print head 3 after passing through the back tension plate 6. After that, printing is performed using the print head 3 while moving the carriage 5. Each time the printing of one line is completed, the printing paper 1 is advanced by one line so that the next line can be printed. At this time, since the printing paper 1 is pressed against the platen 2 by the back tension plate 6, the printing paper 1 is prevented from rising from the platen 2, and accurate paper feeding can be performed.

Problems to be Solved by the Invention However, in the above-described conventional configuration, if the spring constant of the spring 7 is set according to the thin printing paper, the printing force is insufficient due to insufficient spring force when printing on thick printing paper. However, there is a problem that the paper is lifted from the platen 2 and normal paper feeding cannot be performed, the printing quality is deteriorated, and the printing noise is further increased. Conversely, if the spring constant of the spring 7 is set in accordance with the thick printing paper, the spring force is excessive when the thin printing paper is mounted, so that it is difficult to pass between the platen 2 and the back tension plate 6, Even if the printing paper can be mounted properly, there is no slight slippage between the platen 2 and the printing paper 1 required for printing, so that normal paper feeding cannot be performed and the printing quality deteriorates.

Means for Solving the Problems The present invention includes a back tension plate having a first region located with a gap between the platen and a second region provided outside the first region and in contact with the platen. It is a thing.

With the above configuration, even when the spring constant of the spring is set in accordance with the thick paper, the thin paper can be easily mounted by passing through the gap in the first region when the thin paper is mounted, and the back tension can be set. The plate can prevent the printing paper from rising from the platen.

FIG. 1 is a perspective view of a main part of a printing apparatus using a paper feeder according to an embodiment of the present invention, wherein 1 is a printing paper, 2 is a platen, 3 is a printing head (printing means), and 4 is a printing head. The carriage 5 has a carriage shaft, which has the same configuration as the conventional example. Reference numeral 8 denotes a paper guide portion which is positioned with a gap between it and the platen 2 as shown in more detail in FIG.
A back tension plate (plate member) 9 having a sliding portion 8b for making a gap between the paper guide portion 8a and the platen 2 in contact with the platen 2 and the back tension plate 8 toward the platen 2 Biasing spring, 10
Is a shaft for holding the back tension plate 8 rotatably.

The operation of the printing apparatus of the present embodiment configured as described above will be described below.

When mounting thin paper, the print paper 1 is mounted through a gap between the paper guide portion 8a and the platen 2.

Although the paper that is thinner than the gap between the paper guide portion 8a and the platen 2 cannot be pressed by the back tension plate 8, it is easy to follow the outer periphery of the platen 2 because the bending rigidity of the paper is originally low.
Since the paper does not float up beyond the gap between 8a and the platen 2, printing can be performed normally.

Also, for a sheet thicker than the gap between the paper guide portion 8a and the platen 2, an appropriate pressure is applied to the sheet by the back tension plate 8, so that the sheet can be fed properly and printing can be performed normally. .

Advantageous Effects of the Invention The present invention comprises a first region located with a gap between the platen and a back tension plate having a second region provided outside the first region and in contact with the platen, Even if the spring constant of the spring is set according to the thick paper, it can be easily mounted by passing the gap in the first area when mounting the thin paper, and printing from the platen by the back tension plate The floating of the paper can be prevented, and printing can be performed normally. Further, for paper thicker than the gap, an appropriate pressure is applied to the paper by the back tension plate, and printing can be performed.

[Brief description of the drawings]

1 and 2 are perspective views of a main part of a printing apparatus using a paper feeder according to an embodiment of the present invention, and FIG. 3 is a side view of a main part of a printing apparatus using a conventional paper feeder. . 1 ... printing paper, 2 ... platen, 3 ... printing head,
4 ... carriage, 5 ... carriage shaft, 8 ...
Back tension plate, 8a …… Paper guide part,
8b: sliding part, 9: spring, 10: shaft.

Claims (1)

(57) [Claims] 1. A platen rotatably provided for mounting a sheet on an outer peripheral surface thereof; a printing unit for printing on the sheet; holding the printing unit, and movable on the sheet mounted on the platen A plate member provided upstream of the printing unit in the paper transport path; and a biasing unit configured to bias the plate member toward the platen. A paper guide portion provided at a position sandwiching the conveyance path between the platen and extending along a central axis of the platen; a paper guide portion provided at the paper guide portion so as to be located outside the conveyance path; And a sliding portion protruding by a distance, wherein the sliding portion abuts on the platen by the urging means.