JPH0435971A - Thermal printer - Google Patents

Abstract

PURPOSE:To prevent a printing medium from being rubbed by a paper guide part of a carriage and stained by a method wherein a rotating member rotating on the printing medium with the travel of the carriage is provided on the surface of the carriage opposed to a platen. CONSTITUTION:At the time of printing, a carriage 1 moves in an arrow direction A, and a thermal head 5 is pressed on a platen 12. Because printing paper 8 has elasticity, the paper comes into contact with a ball 3 to rotate the ball 3 in an arrow direction B. The head 5 conducts printing on the printing paper 8 using an ink ribbon 7 contained in a cassette 6. Upon completion of one-line printing, the head 5 is retracted from the platen 12 and moves in an arrow direction C. At this time, the ball 3 also returns to a printing start position with the travel of the carriage 1. Because the ball 3 is slightly projected from a guide 2 toward the platen 12, the printing paper 8 certainly comes into contact with the ball 3 first. The ball 3 rotates and rubs on a printing surface with the travel of the carriage 1, thereby preventing the non-printing part of the paper from being stained by the ink adhering on the guide 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal printer used in word processors, computers, etc. [Prior Art] Conventionally, this type of thermal printer has a carriage for guiding paper. The walls are constructed with ribs etc.

Printing was performed by pressing the printing paper against the platen using this carriage.Without this wall, it would be difficult to print on thick paper such as postcards without blurring [Problem to be solved by the invention] However, When using the above-mentioned conventional thermal printer to print a solid or color figure, the carriage moves while the wall is in contact with the printing surface, so some of the printed ink adheres to this wall, and the adhering ink covers the printing paper. This staining becomes more serious as the temperature of the environment in which it is used is higher.Means for Solving the ProblemThe present invention has been developed to solve the problem by providing a surface of the carriage facing the platen. A rotating member is provided that rolls on the print medium as the carriage moves.With this configuration, the rotating member provided on the wall of the carriage comes into contact with the print surface of the print medium, but as the carriage moves, the rotating member rolls over the print medium. Embodiment: An embodiment of the thermal printer of the present invention will be described below.
This will be explained with reference to the drawings. FIG. 1 is a top plan view of the vicinity of the carriage of a thermal printer according to an embodiment of the present invention. In FIG. Guide 2
3 is a ball and is rotatably fixed with a ball cap 4 so that the ball 3 does not come off.
The thermal head prints on the printing paper 8 using the ink ribbon 7 stored in the cassette 6. While the thermal head 5 is pressed against the printing paper, the carriage 1 slides on the carriage shaft 9, and the ink ribbon 7
This is done by melting the ink with heat and transferring it to printing paper.

When this operation is seen in the cross-sectional view shown in FIG. 2, even though the printing paper 8 is always in contact with the ball 3 because it has elasticity, in FIG. 2, 10 is a feed roller;
1 is a pinch roller, 12 is a platen, and 13 is a frame.A thermal printer with a size larger than 10 mm performs the following operations.First, during printing, a carriage 1 moves in the direction of arrow A, as shown in FIG. At this time, the thermal head 5 is not pressed toward the platen 12 by the head driving device, and the printing paper 8 has elasticity as shown in FIG. As the carriage 1 moves, it rotates in the direction of arrow B 4
When one line of printing is completed at the right end, the thermal head 5 is moved away from the platen 12 by the head drive device and moved in the direction of arrow C as shown in FIG. When it returns to the leftmost printing start position, the previous printing is repeated.

In this way, since the ball 3 protrudes a little closer to the platen 12 than the guide 2, the printing paper 8 always comes into contact with the ball 3 first. When the carriage 1 moves, the ball 3 rotates and rubs the printing surface, and this prevents the ink from adhering to the guide 2 and staining the paper in areas that are not supposed to be printed. The present invention is also applicable to a cylindrical roller rotatable around an axis perpendicular to the direction of carriage movement. [Effects of the Invention] As described above, in the thermal printer of the present invention, since the rotating body is provided on the surface of the carriage opposite to the printing surface, it is possible to prevent dirt from being rubbed by the paper guide portion of the carriage other than the printing surface. can.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a thermal printer according to an embodiment of the present invention. FIG. 2 is a sectional view of the vicinity of the carriage of a thermal printer according to an embodiment of the present invention. FIG. Figure 1

Claims (1)

[Scope of Claims] A carriage having a thermal head, a platen provided opposite to the thermal head in parallel to the moving direction of the carriage, and a platen provided on a surface of the carriage facing the platen, of the carriage A thermal printer comprising: a rotating member that rolls on a print medium as it moves;