JPH0467507B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention reciprocates along the printing line a hammer bank that holds a plurality of dot printing hammers provided at intervals along the printing line, and this reciprocating movement This invention relates to a hammer bank drive device for a dot printer that prints in the process of printing.

[Background of the invention]

In such a printer, in order to ensure the prescribed printing quality, that is, the positional accuracy of dot printing, and to ensure dot printing, it is necessary to take into account the load, bending moment, etc. that acts on the hammer bank as it accelerates and decelerates during reciprocating movement of the hammer bank. It is essential to prevent deformation of the hammer bank for the following reasons.

If the hammer bank is deformed and the distance between the printing hammer and the platen (hereinafter referred to as the hammer gap) changes, the printing hammer will no longer be able to maintain a predetermined printing ability. In other words, the repeatability of the printing hammer is greatly reduced due to the increase in the hammer gap.
If the hammer cap becomes wider by just 0.05 mm, the repeatability decreases and it becomes impossible to maintain the specified printing speed. On the other hand, if the hammer cap is narrowed by 0.05 mm, there are problems such as the paper being smudged by the ink ribbon, the ink ribbon not running stably, and the position of the printing hammer changing, causing misalignment of dot printing. occurs.

When the printing speed is increased, the acceleration and deceleration of the hammer bank during reciprocating movement increases, and the load acting on the hammer bank increases, so that the bending moment increases. In order to suppress the deformation of the hammer bank due to the bending moment to below a permissible value, the bending rigidity of the hammer bank may be increased. However, simply increasing the bending rigidity increases the weight of the hammer bank, which poses problems such as making high-speed printing difficult.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to prevent deformation of the hammer bank due to acceleration and deceleration with a simple configuration, and thereby to improve printing quality and printing speed.

[Summary of the invention]

The present invention focuses on the fact that the bending moment can be reduced by aligning the point of force from the shuttle mechanism that reciprocates the hammer bank on the center of gravity line parallel to the printing line of the hammer bank, and the position of the point of force can be secured. The feature is that the method of connecting the hammer bank and the shuttle mechanism has been devised.

[Embodiments of the invention]

Embodiment drawings will be described below with reference to the present invention.
A hammer bank 1 holding a plurality of dot printing hammers 11 provided at a predetermined pitch along a printing line.
The left end of 0 is slidably supported by a slide bearing 21 fixed to a frame (not shown) via a mount block 12 and a shaft 13.
Hammer bank 10 and shaft 13 are each fixed to mount block 12 by bolts 41. Further, the right end of the hammer bank 10 is connected to the shuttle mechanism 30 via a joint plate 40. The shuttle mechanism 30 includes a cam 36 driven by a motor (not shown), a pair of cam followers 31 that contact the cam 36, and the cam followers 31.
Shift plate 32 and screw 3 attached to the top surface
4, the shift plate 32 is fixed to two shafts 33, etc. Shaft 33
is slidably supported by a sliding bearing 22 mounted on the frame, and its left end is attached to the joint plate 40 via a bolt 42. The joint plate 40 has a bolt 43
It is fixed to the hammer bank 10 via. The bolt 43 is positioned on the center of gravity of the hammer bank 10, which is parallel to the printed line. However, the center of gravity line is a line drawn through the center of gravity of the hammer bank 10 and parallel to the direction of reciprocating movement of the hammer bank 10, that is, the direction of the printed line.
50 is an ink ribbon, 51 is a ribbon guide, 52 is a cassette for storing the ink ribbon 50, 53 is a drive roller for driving the ink ribbon 50, 60 is paper, and 70 is a platen.

When the cam 36 rotates, the cam follower 31,
The shift plate 32 and the shaft 33 reciprocate in the left-right direction in the figure, that is, along the printing lines. As a result, the hammer bank 10 also moves back and forth, and in the process of this back and forth movement, the dot printing hammer 11 is driven to perform printing.

The above structure, that is, the joint plate 40
The connecting portion between the hammer bank 10 and the shuttle mechanism 30 is fixed by straddling the two shafts 33 and fixing it to the hammer bank 10 via a bolt 43 located approximately on the center of gravity of the hammer bank 10. Since the rigidity of the hammer bank 10 is increased and the deformation of the connecting portion is reduced, the deformation of the hammer bank 10 is also reduced. Further, since the point of force for accelerating and decelerating the hammer bank 10 by the shuttle mechanism 30 almost coincides with the center of gravity of the hammer bank 10, almost no bending moment is generated as the hammer bank 10 accelerates and decelerates, and the hammer bank 1
0 will no longer be deformed.

When the joint plate 40 is configured to be fixed to only one shaft 33 as shown in FIG. 2, the rigidity of this connecting portion decreases and the connecting portion becomes easily deformed, causing deformation of the hammer bank 10. As it increases, the arm length becomes the distance between the center of gravity of the hammer bank 10 and the center of the shaft 33, and due to the bending moment whose load is the inertial force accompanying the acceleration and deceleration of the hammer bank 10, Bending moments in the indicated directions act on the hammer bank 10 alternately, so that the hammer bank 10 is deformed to curve as shown by the dashed line and the dashed double dot line in the figure.

〔Effect of the invention〕

As explained above, according to the present invention, the point of force from the shuttle mechanism that accelerates and decelerates the hammerbank is made to almost coincide with the center of gravity of the hammerbank, so there is no bending moment caused by acceleration and deceleration of the hammerbank. This makes it possible to prevent the hammer bank from deforming, ensuring print quality and increasing printing speed.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the device of the present invention;
FIG. 2 is a plan view for explaining the deformation of the hammer bank. In the figure, 10 is a hammer bank;
11 is a dot printing hammer, 30 is a shuttle mechanism,
33 is the shaft, 40 is the joint plate, 4
1 to 43 are bolts.

Claims (1)

[Scope of Claims] 1. A dot printer in which a hammer bank holding a plurality of dot printing hammers at predetermined intervals along a printing line is moved back and forth along the printing line by a shuttle mechanism, and printing is performed in the process of this reciprocating movement. , wherein the shuttle mechanism is a separate unit from the hammer bank, and at least two shafts are provided so as to be able to reciprocate on a shift plate loaded with a cam and a cam follower.
A hammer bank drive for a dot printer, characterized in that a book shaft and a hammer bank are connected by a joint plate, and the plate is fixed to the hammer bank near a line of gravity that passes through the center of gravity of the hammer bank and is parallel to the printed lines. Device.