JPH04142966A - Platen gap regulating mechanism - Google Patents

Abstract

PURPOSE:To move a printing head by always holding it horizontally by providing a pair of shafts having gears and eccentric bushes at both ends, a printing head mounting base for mounting movably in a longitudinal direction of the shafts arranged in parallel, and a belt engaged with a pair of gears. CONSTITUTION:When a copy control lever 10 is moved leftward, a front shaft 1 and a rear shaft 2 coupled by gears 7 and a belt 8 are rotated while deviating leftward at the center of eccentric bushes 9 as an axis at the same angle. Thus, a printing head mounting base 4 is moved leftward while holding horizontal toward a flat platen 5, and a platen gap is narrowed. When the gap is increased, the lever 10 may be moved rightward.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a platen gap adjustment mechanism, and particularly to a platen gap adjustment mechanism in a serial printer.

[Conventional technology]

FIG. 4 is a side view showing an example of a conventional platen gap adjustment mechanism.

A front shaft 41 and an eccentric rear shaft 42 are mounted in parallel to a print head mount 44 on which a print head 43 is mounted. Further, a flat platen 45 is disposed at the tip of the print head 43 so as to face it.

Next, the operation of this example will be explained.

First, in order to widen the platen gap between the printing wire 46 and the flat platen 45, the rear shirt l-2 is rotated to the right. Since the rear shaft 42 is eccentric, the rear shaft 42 side of the print head mount 44 is lowered around the front shaft 41, and the tip of the print head 43 separates from the flat platen 45 while rotating around the front shaft 41. Furthermore, to narrow the platen gap, the operation can be completely reversed.

[Problem to be solved by the invention]

The conventional platen gap adjustment mechanism described above adjusts the platen gap while rotating the print head around the front shaft 1, so the difference in the platen gap becomes larger on both sides above and below the printing wire, and the platen gap has a wide response frequency. The disadvantage is that the printing speed cannot be increased because the printing speed is limited by the low printing wire speed.

[Means to solve the problem]

The platen gap adjustment mechanism of the present invention includes: a pair of shafts having gears and eccentric bushings on both sides; The apparatus is characterized by comprising a print head mount movably attached to the pair of parallel shafts in the longitudinal direction, and a belt placed around the pair of gears.

〔Example〕

Next, the present invention will be explained with reference to FIGS. 1 to 3.

FIG. 1 is a perspective view showing one embodiment of the platen gap adjustment mechanism of the present invention, and FIGS. 2 and 3 are views taken along arrow AA in FIG. 1 showing the state before and after the operation of this embodiment, respectively. be.

First, the structure will be explained. In FIG. 1, a front shaft 1 and a carrier shaft 2 are passed through the print head mounting base 4 so as to be parallel to each other, and both shafts are movable in the longitudinal direction.

Also, front shaft 1. A gear 7 is press-fitted into each of the rear shafts 2 and connected by a belt 8. Furthermore, eccentric bushings 9 are press-fitted into both sides of the front shaft] handler shaft 2. Furthermore, a copy control lever 1o is attached to the left end of the front shaft 1, and a print head 3 is attached to the print head mounting base 4. A flat platen 5 is arranged to face the tip of the print head 3.

Next, the operation of this embodiment will be explained.

First, let us assume that we are in the state shown in Figure 2.

In order to narrow the platen gap G, move the copy control lever 1o to the left in FIG. It rotates eccentrically around the center of 9. As a result, the print head I to the mounting base 4 move to the left toward the flat platen 5 while remaining horizontal, and the platen gap narrows as shown in FIG.

It is clear that the copy control lever 1o can be moved to the right in order to widen the platen gap.

〔Effect of the invention〕

As explained above, the present invention provides a serial printer with a pair of shafts having gears and eccentric bushings on both sides, a print head mounting base in which the shafts are arranged in parallel and movable in the longitudinal direction of the shaft, and a pair of gears. Since the print head always moves while keeping it horizontal, the platen gap between the print wires on both the upper and lower sides is the same. The difference in the platen gap between the upper and lower sides of the printing wire becomes large, and the platen gap is wide.The response frequency is no longer limited by the speed of the printing wire, which is low, so printing speed can be increased. have an effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the platen gap adjustment mechanism of the present invention, FIGS. 2 and 3 are views taken along the arrow AA in FIG. 1 showing the state before and after the operation of this embodiment, respectively. FIG. 4 is a side view showing an example of a conventional platen gap adjustment mechanism. 1.41... Front shaft, 242... Rear shaft, 3.43... Print head, 4, 44... Print head mounting base, 5, 45... Flat platen, 6
．． 46... Printing wire, 7... Gear, 8... Belt, 9... Eccentric bushing, 10... Copy control leno (-

Claims (1)

[Claims] A pair of shafts having gears and eccentric bushings on both sides, a print head mount mounted to be movable in the longitudinal direction of the pair of shafts arranged in parallel, and a belt placed around the pair of gears. Features a platen gap adjustment mechanism.