JPS6329566Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device having a circular platen, such as a dot line printer.

Conventionally, in a dot line printer as shown in FIG. 1, when the printing speed becomes high, it is difficult to rotate the platen 1 in synchronization with the paper feeding speed.

Therefore, printing is performed with the platen 1 fixed, but when loading the paper 2 and the ink ribbon 3, it is necessary to open the space between the hammer 4 and the platen 1. Further, in order to prevent the paper 2 from overshooting, etc., it is necessary to apply an appropriate brake to the paper 2. The brake plate 5 and the coil spring 6 are parts for braking paper. This braking component also needs to be opened when loading paper. If these are formed in the platen assembly 12 and the platen assembly 12 is opened and closed,
Paper loading is easy.

Examples of such structures are shown in FIGS. 2 and 3.
When the handle 7 is moved in the direction of the arrow 8, the foot lever 9 is lifted in the direction of the arrow 10, disengages from the pin 11, and the platen assembly 12 is opened by the tension spring 13 to the position shown by the two-dot chain line.The center of rotation is at the hinge. This is the shaft 15. Conversely, when closing, the handle 7 can be moved in the direction of the arrow 16.
The platen 1 is fitted onto a side plate 17. The handle 7 and the core rod 18 are connected by a screw 21.

In such a structure, the platen 1 is always struck at the same location. Especially hammer 4
When the platen 1 has a dot shape as in this example, the surface of the platen 1 is subject to severe wear. Wear of the platen 1 not only causes a decrease in printing quality but also increases resistance to paper running, causing a paper jam.

The purpose of the present invention is to eliminate the drawbacks of the prior art described above, prevent abnormal wear on the platen surface, and extend the life of the platen.

This invention uses a mechanism to open and close the platen,
By using a friction roller incorporating a one-way rotating clutch roller, the platen is rotated little by little each time it is opened or closed.

An embodiment of the present invention is shown in FIGS. 4 and 5.

A friction roller 20 fixed to the outer periphery of a one-way rotating clutch roller 19 is fitted into a core rod 18 to which the handle 7 is fixed.

In order to open the platen assembly 12, when the handle 7 is moved in the direction of the arrow 8, the core rod 18 and the one-way rotating clutch roller 19 are brought into a clutch state.
0 will move platen 1. When closing, the one-way rotating clutch roller 19 is in a released state, so the friction roller 20 does not move and the platen 1 does not rotate.

Therefore, each time the platen assembly 12 is opened or closed, the platen 1 rotates and the entire circumference of the platen 1 can be used, which prevents abnormal wear on the surface of the platen 1 and extends its life.

Although the present invention has been described using a friction roller, the same effect can be obtained by using a gear instead of the friction roller and mounting the gear on the platen side.

According to the present invention, the operability is the same as the conventional technology,
In addition, the platen rotates little by little each time the platen is opened or closed, thereby extending the life of the platen.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the prior art, FIG. 2 is a side view showing the opening/closing mechanism of the platen assembly of the prior art, FIG. 3 is a top view of FIG. A sectional view showing one embodiment of the invention, FIG.
It is a top view of a figure. In the figure, 1 is a platen, 2 is paper, 3 is an ink ribbon, 4 is a hammer, 5 is a brake plate, and 6
is a coil spring, 7 is a handle, 9 is a foot lever,
11 is a pin, 12 is a platen assembly, 13 is a tension spring, 15 is a hinge shaft, 17 is a side plate, 18
is a core rod, 19 is a one-way rotating clutch roller, 20
is a friction roller.

Claims (1)

[Claims for Utility Model Registration] A printing device comprising a printing hammer and a circular platen that receives the impact of the printing hammer, the platen being rotatably supported, and the printing position in the closed position and the printing position in the closed position. a platen support that can be opened and closed between a retracted open position and a standby position; a handle that rotates the platen support;
A drive means is attached to a shaft rotated by the handle via a one-way clutch and rotates the platen when the handle rotates, and the platen is rotated each time the platen support is opened or closed. printing equipment.