JPS59103768A - Printing hammer - Google Patents

Abstract

PURPOSE:To enable to obtain a high-efficiency and high-speed printing hammer, by a method wherein a link mechanism is deflected through expansion and contraction of piezoelectric elements fixed to a frame to thereby print, in a dot impact type printer. CONSTITUTION:When a voltage is impressed between terminals 12, 12', the piezoelectric elements 1, 1' fixed to upper and lower parts of a printing hammer frame 2 are impressed with the voltage through respective electrodes 3, 3' and 4, 4', whereby they are rapidly contracted, and high pressures are exerted on movale links 7, 8 in vertical directions through shafts 6, 6'. In this case, the links 7, 8 are previously slightly deflected forwards, so that the link 8 is rotated with the shaft 6' as a center, a printing pin 9 is rightwardly projected with a high magnification ratio, and collides against a platen through a ribbon and a printing paper, thereby printing a dot. Accordingly, a high-efficiency high-speed printing hammer can be easily obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing hammer for a dot impact printer that prints a single character or figure in a dot matrix.

The printing mechanism of conventional dot impact printers includes:
Electromagnets have often been used to convert electrical to mechanical energy. The electromagnetic printing mechanism is extremely inefficient due to Geel heat caused by the excitation coil and the eddy current caused by changes in the magnetic flux flowing through the yoke and armature, and the loss of hysteresis.The mechanical energy effective for printing is limited to the input electrical energy. Compared to this, most of the input energy is extremely small and dissipated as heat, unnecessarily increasing the temperature of the device. Since a large amount of input energy is required, the drive circuit is also large and bulky, which inevitably requires a large power supply, leading to an increase in the price of the entire device. In addition, since electromagnets are mainly composed of iron and copper wire, the printing mechanism becomes heavy, and this trend is becoming more pronounced as printers become faster, hindering printers from becoming faster, smaller and lighter, and ultimately lower in price.

In order to avoid this difficulty, a printing mechanism using a piezo element is proposed in patent applications () and () filed simultaneously with the present application. However, in these printing mechanisms, since a leaf spring is used as a printing hammer, the displacement output of the piezo element cannot be sufficiently expanded.

The present invention provides a printing hammer with a large displacement output by utilizing a link mechanism that is bent by the expansion and contraction of a piezo element as a printing hammer.

The present invention is a printing hammer that utilizes the deformation of the piezo element due to electrostatic polarization and bends the link mechanism to expand the amount of deformation of the piezo element to obtain the displacement necessary for printing. Therefore, it is possible to provide an extremely efficient high-speed printing hammer that has a simpler structure and generates less heat than conventional printing hammers using electromagnets. Also, since a link mechanism is used as the printing hammer, it is possible to easily obtain a large magnification.

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

Referring to FIG. 1, one embodiment of the present invention includes a printing hammer frame 2 to which piezo elements 1 and 1' are fixed;
It has a fixed link 5 fixed to the upper surface of the piezo element 1 and a fixed link 5' fixed to the lower surface of the piezo element 1'. The right ends of the fixed links 5 and 5' are provided with shafts 6 and 6', respectively. A movable ring 7 is rotatably attached to the shaft 6, and a movable ring 8 is attached to the shaft 6'.
A printing pin 9 is fixed to the tip of the printing pin 9. The movable links 7 and 8 are rotatably connected to each other by a shaft 10 at the center thereof.

The frame 2 has a protruding stopper 11.

When the movable link 7 is stopped, it is in contact with the stopper 11 such that the center of the shaft 1o is located slightly to the right of the line connecting the centers of the shafts 6 and 6'. Electrode 3 of piezo elements 1 and 1'
Terminals 12 and 12' are provided for applying voltage between and 3' and 4 and 4'.

In this embodiment, as is clear from FIG. 1(B), a plurality of printing hammers having the configuration shown in FIG. 1(5) are arranged at regular intervals.

Now, when voltage is applied between terminals 12 and 12', piezo elements 1 and 1' contract rapidly, and large pressure is applied to movable links 7 and 8 in the vertical direction via shafts 6 and 6'. Because it is added, it is refracted. At this time, the movable link 7.8 is bent slightly forward to the right in advance, so the movable link 8 rotates counterclockwise about the shaft 6', and the printing pin 9 projects to the right.

A printing operation is performed by colliding with a platen (circuit) with the ribbon and printing paper (circuit) in between. Terminal 12.12'
When the voltage between them is removed, the piezo elements 1 and 1' return to their original dimensions and the movable link 7.8 also returns to its original size. The amount of displacement ε of the printing pin 9 during this printing operation is between the piezo elements 1 and 1.
The displacement amount of ' is each δ, the distance between the axis 6 and the axis 10 is l, and the distance between the axis 6' and the axis lO is also l.The dimension between the axis 6' and the printing pin 9 is 1. Since a large magnification can be obtained, the amount of displacement of the printing pin 9 required for printing can be easily obtained.

In this embodiment, the link mechanism is configured so that it bends when the piezo element contracts, but it is also possible to configure the link mechanism so that it bends when the piezo element expands.

As explained above, the present invention uses a link mechanism that bends when the piezo element expands and contracts, thereby easily increasing the amount of strain on the piezo element, resulting in high efficiency, high speed, and low cost printing. This is something that the community can provide.

[Brief explanation of drawings]

FIG. 1(5) and fB) are a side view and a front view of an embodiment of the present invention. 1.1'... Piezo element, 2... Printing frame, 3.3'... Electrode s of piezo element 1 4.4'... Piezo element 1' electrode, 5\
, 5'... Fixed link, 6.6'...
Axis, 7...possible tlr') link, 8...
Movable link, 9... Printing pin, 10... Axis, 11... Stopper +, 12.12'...
...Terminal. (A) 1st leap (B)

Claims (1)

[Claims] A printing machine characterized by having a frame which is a structure of a printing mechanism, a piezo element fixed to the frame, and a link mechanism configured to bend as the piezo element expands and contracts.