JPH0573595B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a print head position adjustment device used in printers, typewriters, etc.

BACKGROUND OF THE INVENTION In recent years, in order to improve the efficiency of printing operations, printing devices such as printers and typewriters have increasingly used methods of stacking multiple sheets of paper at once to make original copies at the same time. Therefore, it is necessary to change the gap between the print head and the platen depending on the thickness of the paper. Conventionally, print head position adjustment devices include devices that eccentrically center the axis of an auxiliary shaft and rotate the shaft to change the height, change the gap between the print head and the platen, and move the platen back and forth.

A conventional print head position adjustment device will be described below.

FIG. 8 shows a side view of a conventional print head position adjustment device. 1 is a platen, 2 is a main shaft, 3 is a main shaft sleeve, and the main shaft 2 passes through the main shaft sleeve 3. 4 is an auxiliary shaft that passes through the auxiliary shaft sleeve 5. Eccentric pins 12 are provided at both ends of the auxiliary shaft 4. Reference numeral 7 denotes a pedestal, and 8 a ribbon cassette, which is supported by the pedestal 7. Reference numeral 9 denotes a printing head incorporating a printing hammer 9a, 6 a type selection motor, and 10 a daisy wheel in which type is arranged radially. 11 is a carriage base.

The operation of the conventional print head position adjusting device constructed as described above will be explained. FIG. 9 shows the change in position when the print head position is adjusted in FIG. If the gap between the platen 1 and the tip of the printing head 9 is widened, when the auxiliary shaft 4 rotates around the eccentric shaft 12, the carriage base 11 rotates around the main shaft 2, and the carriage base 11 rotates around the main shaft 2. The engaged printing head 9 also rotates at the same time, and the gap between the platen 1 and the printing hammer 9a of the printing head 9 becomes larger. On the other hand, if you want to reduce the gap, you can do the opposite of the above.

Problems to be Solved by the Invention However, the conventional print head position adjusting device as described above has a problem in that eccentric machining of the eccentric mechanism is extremely difficult and costs increase.

Means for Solving the Problems In order to solve the above conventional problems, the present invention has the following features:
a platen having a printing surface; a main shaft supported parallel to the printing surface of the platen; an auxiliary shaft supported parallel to the main shaft; The printing head includes a carriage movable along the printhead, a print head mounted on the carriage and facing the platen, and a cam slidable between the auxiliary shaft and the carriage and having a slope.

Function In the above configuration, by rotating the carriage around the main shaft using the slope of the cam, the gap between the printing head mounted on the carriage and the printing surface of the platen can be adjusted.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 13 denotes an auxiliary shaft, both ends of which are fixed to a chassis (not shown).
14 is a sleeve through which the auxiliary shaft 13 passes. A slide cam 15 has a sliding surface with a slope on the carriage base 20. A movable cam 16 is guided by a groove 15a of the slide cam 15 and is movable in parallel with the auxiliary shaft 13. 17
18 is a cam fixing metal fitting, and 18 is a positioning spring, which is biased by a wave-shaped protrusion provided on the lower surface of the movable cam 16, and positions the movable cam 16. 19
1 is a ribbon cassette, 1 is a stand, 22 is a type selection motor, 23 is a print head, 24 is a daisy wheel, 25 is a platen, 26 is a sleeve, and 27 is a main shaft. FIG. 2 shows a plan view of the main parts. FIG. 3 shows a side view of the main parts before they are moved. FIG. 4 shows a plan view of the main parts before they are moved. FIG. 5 shows a side view of the main parts after they have been moved. FIG. 6 shows a plan view of the main parts after they have been moved. 2 to 5, when the movable cam 16 is moved in the A direction, the slide cam 15 is moved in the B direction and the carriage base 20 is lowered in the C direction. As a result, the carriage base 20 rotates counterclockwise around the main shaft 27,
The gap between platen 25 and print head 23 widens. In order to reduce the gap between the print head 23 and the platen 25, the operation described above can be reversed.

As described above, according to this embodiment, in a printing device that can print on sheets of various thicknesses, the printer is simply installed in the carriage body without using a large-scale structure such as an eccentric mechanism as in the past. By moving the lever to the left or right, it is possible to easily change the distance between the printing head and the printing surface of the platen.

Effects of the Invention The present invention is equipped with a sliding cam having a slope between the auxiliary shaft and the carriage, so the carriage can be rotated about the main shaft by utilizing the slope of the movable cam. Therefore, since the gap between the printing head and the printing surface of the platen can be adjusted, there is no need to use an eccentric mechanism that requires high processing precision.

[Brief explanation of the drawing]

Fig. 1 is a side view of a print head position adjustment device showing an embodiment of the present invention, Fig. 2 is a plan view of the main parts, Fig. 3 is a side view of the main parts before movement, and Fig. 4. is a plan view of the same essential parts before they are moved, Figure 5 is a side view of the same important parts after they are moved, and Figure 6 is a plan view of the same important parts after they are moved.
FIG. 7 is a perspective view of the main parts, FIG. 8 is a side view of a conventional print head position adjustment device, and FIG. 9 is a side view of the same device in a position adjustment state. 13...Auxiliary shaft, 15...Slide cam, 16...Movable cam, 17...Cam fixing metal fittings,
18...Positioning spring.

Claims (1)

[Claims] 1. A platen having a printing surface, a main shaft supported parallel to the printing surface of the platen, an auxiliary shaft supported parallel to the main shaft, and an auxiliary shaft rotatable about the main shaft and supporting the main shaft. a carriage movable along the axis of the shaft; a print head mounted on the carriage and facing the platen;
A printhead position adjustment device comprising a sloped cam slidable between the auxiliary shaft and the carriage.