JPS6324475B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-impact type printing device such as a thermal type, a thermal transfer type, or a discharge destruction type.

FIG. 1 schematically shows a thermal printing device among conventional non-impact printing devices, in which a guide rail 3 is always biased to rotate in one direction by a coil spring 1 via a lever 2. As shown in FIG. This force presses the thermal printing head 4 through the thermal recording paper 5 against the platen 7 fixed to the support base 6, and in this state the head generates heat to perform printing. By the way, in the above conventional example, the coil spring 1 and the lever 2
etc., is required outside the printing column, and the structure is also complicated.

Therefore, what is shown in FIGS. 2 and 3 has been proposed. Here, the platen 8 is rotatably supported on a shaft 9, and is given the ability to rotate in the direction of the heat-generating print head 12 by coil springs 11 and 11' interposed between it and the frame 10 of the printing device. There is. The print head 12 is rotatably supported on a shaft 13, and is pressed by the platen 8 so that its rear protrusion comes into contact with the guide surface 10a of the frame 10. In this state, the print head 12 moves left and right to perform printing, but this configuration eliminates the need for a mechanism for pressing the print head against the platen outside of the print column, allowing for miniaturization. Although the platen 8 and the printing head 12 remain in pressure contact during paper feeding, the paper is fed while the printing head is being fed in the digit direction, so no paper tangles occur. By the way, in this method, the pressure contact force between the platen 8 and the printing head 12 is adjusted by the coil springs 11 and 11'.
It is difficult to apply equal force to the left and right sides, and the printing pressure on the left and right sides inevitably differs. Therefore, when printing one line, there may be a difference in print density between the left and right sides, and the sliding friction between the guide surface 10a and the print head 12 may
Since this varies depending on the position of the print head 12, the movement of the print head 12 may not be smooth, resulting in irregular printing.

The present invention has been made to address the above-mentioned drawbacks,
The purpose of this invention is to prevent variations in the printing pressure of the print head that occur when the device is configured to be compact as in the conventional example, and to allow the print head to move smoothly.

The following embodiment to which the present invention is applied is a non-impact printing device that prints by moving the print head in the digit direction with the print head pressed against the platen. This is a non-impact type printing device in which the printing head is provided with means for pressing against the platen. The pressing means is mounted between a moving member that follows the movement of the print head in the digit direction and is prevented from moving away from the print head by a guide member, and the moving member and the print head. and a spring member that presses the print head against the platen.

FIG. 4 shows a printing device according to an embodiment of the present invention. Reference numeral 14 denotes a self-aligning platen, which is rotatably supported around a shaft 15 fixed to the frame of the printing device (not shown), and has a width corresponding to the number of printing digits in a direction perpendicular to the plane of the paper in the figure. have. Reference numeral 16 denotes a heat-generating print head in which heat-generating elements are arranged in a dot matrix, and is rotatably supported on a shaft 17 fixed to a frame (not shown). Print head 16 is on axis 1
7 over the entire width of the platen 14. 18 is connected to the shaft 17 at its lower end 18a, 18a'.
This is a head pressing lever that fits into the print head 16 and holds the print head 16 from both sides. Information desk 19
is part of the printing device frame, and platen 1
A guide surface 19a for guiding the head press lever 18 is formed parallel to the head press lever 18 and the shaft 17. A coil spring 20 is installed between the head pressing lever 18 and the printing head 16, and the printing head 16 is pressed against the platen 14 via the recording paper 5 by its elastic force. The platen 14 is self-aligning, and when pressed against the print head 16, rotates according to the inclination of the print head 16, so that the print head 16 is always in good surface contact with the platen. The pressing force of the print head is determined by the strength of the coil spring 20, and the pressing force is uniform over the entire width of the platen 14. Also, the printing head 16 is in pressure contact with the platen 14 during paper feeding, but paper tangles do not occur because the paper feeding is performed when the printing head moves in the digit direction.

FIG. 5 shows another embodiment, in which a cylindrical guide rail 21 is used to guide the head pressing lever 18. This reduces the frictional force exerted on the head press lever 18 and presses the print head 16.
The movement in the digit direction becomes smoother.

As described above, since the printing head is provided with a means for pressing the head against the platen, there is no need to provide a means for pressing the head against the platen outside of the printing column of the platen, and the printer can be miniaturized and the printing pressure of the printing head can be reduced. is constant, the movement of the head becomes smooth, and printing irregularities do not occur. Further, the means for pressing the print head against the platen includes a moving member that follows the movement of the print head in the digit direction and is prevented from moving away from the print head by a guide member;
Since it is composed of this moving member and a spring member installed between the print head and presses the print head against the platen, the structure is small and simple, assembly and adjustment are also simplified, and noise caused by backlash is reduced. .

Further, in the present invention, since the parallel shaft serves both as the center of rotation of the print head and as a guide during reciprocating movement of the print head, the apparatus can be made more compact with fewer parts. In addition, the print head is held rotatably about a parallel axis, and the print head is pressed against the platen between the print head and a holding member that is movable back and forth about the parallel axis. By providing a spring member for this purpose, variations in printing pressure can be prevented, and the
Even if the recording paper is fed while the print head is pressed against the platen (i.e., the print head is not raised or
(There is no need to provide a special down mechanism), and it is now possible to reduce the skew of the recording paper more than ever before.

[Brief explanation of the drawing]

Fig. 1 is an overview perspective view of a conventional example, Figs. 2 and 3 are sectional views of other conventional examples, Fig. 4 is a sectional view of an embodiment of the present invention, and Fig. 5 is a sectional view of another embodiment. figure. 14...platen, 16...heat-generating print head, 1
8... Head pressing lever, 19... Guide stand, 20... Coil spring, 21... Guide rail.

Claims (1)

[Scope of Claims] 1. A non-impact printing device for printing on recording paper, comprising: a platen rotatably supported around a rotation axis; and a parallel axis provided along the platen. a print head having a heat generating element and provided opposite to the platen; and a print head that holds the print head rotatably about the parallel axis and is movable back and forth about the parallel axis. a holding member; a spring member provided between the holding member and the printing head for pressing the printing head against the platen; a guide member for guiding the rear of the holding member, and moving the print head along the parallel axis while pressing the print head against the platen through the recording paper; A non-impact printing device characterized in that it is configured to feed the recording paper.