JPS6133714B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device, and particularly to a platen positioning mechanism of a printing device, such as a wire printing head mechanism, which positions the platen so that the distance between the printing surface of printing paper and the printing head is kept constant. .

Conventionally, in printing devices, the distance between the printing head and the printing surface of the printing paper is small, and good printing cannot be achieved unless it is kept constant. A mechanism in which the print head is moved using a servo mechanism is known, but
In this case, the head moving mechanism and thickness detecting mechanism are complicated and expensive.

Additionally, as a mechanical method, a mechanism is known in which the printing head or a mechanism provided on the printing head is directly pressed against the printing paper to maintain a constant distance between the printing head and the printing surface of the paper. There was a drawback that the print surface was pressed due to movement and lateral movement of the print head, resulting in smearing. Further, since force is applied to the printing head carrier, there is a problem in the longevity and reliability of the mechanism.Furthermore, when the thickness of the medium changes due to longitudinal movement of the medium, such as in a bankbook, this movement is hindered.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a platen positioning mechanism that can position the platen so as to maintain a constant distance between the print head and the printing surface of printing paper.

According to the present invention, there is provided a platen movable in the normal direction of the printing surface, a pressing means for pushing the platen toward the printing head, and a unidirectional movement restraint for suppressing movement of the platen in the direction toward the printing head. means, a stopper for stopping the platen in a predetermined position when the restraint of the unidirectional movement restraining means is released; A platen positioning mechanism for a printing device is obtained, which includes a pushing and releasing means for pushing and moving the platen.

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 3 show one embodiment of the present invention, respectively, and show a carrier guide member 3 that laterally guides a print head 1 and a print head carrier 2 on which the print head 1 is mounted, and a platen guide integrated with a platen 4. platen guide guide members 6 and 6' for guiding the movement of the parts 5 and 5' toward the printing head;
A pressing spring 7 that presses the platen 4 toward the printing head, link levers 8 and 8' that are engaged with the platen guide portions 5 and 5', and ratchet levers 9 and 9' that are engaged with the link levers 8 and 8'. lock levers 10 and 10' that engage with the teeth of the platen 4 and fix the movement of the platen 4 in the direction of the print head;
(rotates around a shaft 21), pressing springs 11 and 11' that press the lock levers 10 and 10' against the ratchet levers 9 and 9', and a reset lever connected to the magnet 12 that restores the fixation of the platen 4 to its initial state. 13, reset springs 14 and 14' which facilitate the restoration of the ratchet levers 9 and 9', and a stopper 15 which determines the initial position of the platen.

Next, the operation will be explained. When the printing paper 22 is inserted into the printing position, the printing head carrier 2 is retracted in the lateral direction of the paper passing area, and the printing paper 2
It is in a state where it does not interfere with the movement of 2. The printing head carrier 2 carrying the printing head 1 on which the printing paper 22 is inserted into the printing position is guided by the carrier guide member 3, and the printing paper 22 and the platen 4 are moved by rollers (not shown) provided on the printing head carrier 2.
is moved in the printing direction while being pressed downward, and as a result of this movement, the platen 4, which is integrated with the platen guide parts 5 and 5', is guided by the platen guide guide members 6 and 6' and moves downward. Also, the link levers 8 and 8', which are engaged with the platen guide parts 5 and 5' via the shaft 16, rotate about the shaft 17 (rotated counterclockwise in FIG. 1). The ratchet levers 9 and 9' engaged through the shaft 18 rotate around the shaft 19 (the first
The platen 4 (rotated to the left in the figure) is moved in the direction of the printing head, and is fixed by the lock levers 10 and 10' at a position moved by the thickness of the printing paper 22, so that the position of the platen 4 is also fixed.

Next, after printing is completed, the reset lever 13 is rotated around the shaft 20 by suction with the magnet 12 (rotated counterclockwise in FIG. 1) to disengage the ratchet levers 9 and 9' and the lock levers 10 and 10'. The platen 4 is restored to its initial state in contact with the stopper 15 by the pressing spring 7 pressing it in the direction of the printing head.

If the thickness of the printing paper changes in the vertical direction, such as in a bankbook, the Ichimoku magnet 12 is activated to restore the position of the platen 4 to its initial state when it passes the center hold (stitch). After that, the printing paper and the platen 4 are pressed again by the roller provided on the print head carrier 2 to reposition the platen 4.

As explained above, the present invention provides a pressing means for pushing the platen toward the printing head, and a unidirectional movement inhibiting means for inhibiting the movement of the platen toward the printing head, so that the printing surface of the printing paper can be moved. This has the effect of keeping the distance between the print head and the print head constant and not placing any load on the print head carrier.

[Brief explanation of the drawing]

1 to 3 are a side view, a plan view, and a front view, respectively, showing an embodiment of the present invention. 1... Print head, 2... Print head carrier, 3... Carrier guide member, 4... Platen,
5 and 5'...platen guide part, 6 and 6'...platen guide guide member, 7...pressing spring, 8 and 8'...link lever, 9 and 9'...ratchet lever, 10 and 10'...lock lever , 11 and 11'... Spring, 12... Magnet, 1
3...Reset lever, 14, 14'...Reset spring, 15...Stopper, 22...Printing paper.

Claims (1)

[Claims] 1 A platen movable in the normal direction of the printing surface,
a pressing means for pushing the platen toward the printing head; a unidirectional movement inhibiting means for inhibiting movement of the platen in the direction toward the printing head; A printing device comprising: a stopper that stops the platen at a predetermined position; and a pushing means that moves integrally with the printing head and pushes and moves the platen through the printing paper against the pressing means. Platen positioning mechanism.