JPS6270058A - Carriage mechanism in line printer - Google Patents

Abstract

PURPOSE:To reduce the power consumption of a linear motor and to increase the rebound force of a shuttle at its stroke ends, by making use of the repulsion force of a permanent magnet or an electromagnet. CONSTITUTION:A shuttle 3 consists of; a printing block base 3a, slide bearings 3b which are set at the ends of the base 3a and reciprocated along a fixed shaft 2, two arms 3c projecting from the ends of the base 3a in parallel with each other, and a movable shaft 3d for a linear motor 4 supported by the arms 3c. The linear motor 4 with an alternating pulse current supplied reciprocates the shuttle 3 along the fixed shaft 2. permanent magnets 6 and 7 are respectively fixed on the faces of bearings 5 supporting the movable shaft 3d at the ends of the linear motor 4 and on the opposing faces of the arms 3c. The permanent magnets 6 and 7 are so disposed that the surfaces thereof the same poles are opposed to each other across a small gap at the stroke ends of the shuttle 3. Therefore, the actions of the shuttle by the linear motor, i.e. deceleration, stop, and inverse acceleration, can be supplemented by the repulsion force of the magnets opposed to each other at their faces.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a carriage mechanism of a line printer in which hammer-driven wires are provided at regular dot intervals in the horizontal direction and one line of printing is performed using a plurality of wire heads. It is.

[Background technology] This line printer, for example, has printing wires for the total number of characters in one line, slides a shuttle carrying a printing block laterally by the number of horizontal dots for one character, and uses multiple wire heads to print. While printing one line, the printing paper is intermittently fed one dot at a time in the vertical direction. In order to reciprocate the shuttle in the horizontal direction, motor rotation was conventionally converted into linear motion using cams, links, etc., but in recent years, as printers have become faster and smaller,
A system has been developed in which the shuttle is directly driven using a linear motor (voice coil motor) that does not require a transmission end. This involves installing linear motors at both ends of the shuttle, and driving the shuttle in the opposite direction once it has reached the end.The shuttle, which has inertia, is then decelerated to a stop and then accelerated in the opposite direction. To do this, a very large amount of energy is required.Therefore, when attempting to speed up printing, the power consumption of the linear motor increases rapidly, making it difficult to downsize the linear motor.

Another possibility is to use a stopper to reverse the shuttle, but even if a cushioning material is used for the stopper, there is a problem in that the structure of the printing block cannot withstand impact.

In order to reduce the power consumption and improve the acceleration of the above-mentioned linear motor, a method of using an electromagnet together with the linear motor is disclosed in JP-A-59-83671 or JP-A-59-101.
Proposed in No. 380. When the shuttle reaches the end of its stroke, an electromagnet is energized to attract the shuttle in the return direction. Although this method reduces the power consumption of the linear motor,
Since it is necessary to pass current through the electromagnet, the overall power consumption does not decrease.In fact, since the movable iron piece of the electromagnet is located outside the coil, the force generated in response to the excitation current is reduced compared to a linear motor, so the overall power consumption is reduced. The disadvantage is that it requires a shaped electromagnet.

[Object of the Invention] The present invention has been made in view of the above problems, and its purpose is to reduce the power consumption of a linear motor by utilizing the repulsive force of a permanent magnet or an electromagnet. An object of the present invention is to provide a carriage mechanism for a line printer that can improve the reversing force at the end of the stroke of a shuttle.

[Disclosure of the Invention] The carriage mechanism of the line printer according to the present invention uses a linear motor to oscillate a shuttle carrying a printing block, and a permanent magnet that faces a permanent magnet fixed to the shuttle at both ends of the stroke of the shuttle. A magnet or electromagnet is fixed to the printer body, and the feature is that the deceleration, stopping, and reverse acceleration of the shuttle by a linear motor are assisted by the repulsive force of the magnets facing each other. be.

[Embodiment] FIG. 1 shows an embodiment of the present invention, in which a printing block consisting of a plurality of hammer heads 1 is mounted on a shuttle 3 that is slidably inserted into a fixed shaft 2. As shown in FIG. The shuttle 3 includes a printing block base 3a, sliding bearings 3b provided at both ends of the base 3a and reciprocating on the fixed shaft 2, and two arms protruding in parallel from both ends of the base 3a. 3c
The shuttle 3 is supported by both arms 3c and a movable shaft 3d of a near motor 4. By supplying an alternating pulse current to the linear motor 4, the shuttle 3 is reciprocated on the fixed shaft 2. ing. The bearings 5 supporting the movable shaft 3d on both sides of the linear motor 4 and the respective arms 3c have permanent magnets 6 and 7 facing each other, respectively.
are fixed, and both permanent magnets 6 and 7 are arranged at both ends of the stroke of the shuttle 3 so that the same poles face each other with a slight distance from each other.

The embodiment shown in FIGS. 2(a) and 2(b) uses an electromagnet 8 instead of the fixed-side permanent magnet 6 in FIG.
(C) As shown in the figure, during the printing portion of the stroke D1 of the shuttle 3, the electromagnet 8 is not energized and the shuttle 3
When the permanent magnet 6 enters both end portions D3 of the stroke, the electromagnet 8 to which the permanent magnet 6 approaches is energized.

FIG. 3 is for explaining in more detail the operation of the carriage mechanism shown in FIG. a
) will have a waveform as shown by the solid line. In the printed portion D2 of the stroke of the shuttle 3, the sliding speed of the shuttle 3 is determined by the response frequency of the hammer, so in order to increase the speed, the deceleration and acceleration at both end portions D3 of the stroke are made faster, and the dashed line As shown, the start-up must be quick. For this purpose, as shown by the broken line in FIG. 4(b), it is necessary to flow a large current through the linear motor 4, which causes the problem that the linear motor 4 becomes large in size. The permanent magnets 6 and 7 or the electromagnets 8 in FIG. Figure 4 (a) due to the repulsive force
) can realize a waveform equivalent to the broken line.

[Effects of the Invention] As described above, the present invention provides a line printer in which a shuttle is oscillatedly driven by a linear motor, in which a permanent magnet or an electromagnet faces a permanent magnet fixed to the shuttle at both ends of the stroke of the shuttle. is fixed to the printer body, so the deceleration, stopping, and reverse acceleration operations of the shuttle by the linear motor can be assisted by the repulsive force of the magnets facing each other, thus increasing the size of the linear motor. It has the advantage of increasing the reversing force at the end of the shuttle's stroke and increasing the printing speed without causing any problems.Also, since it uses the repulsive force of a permanent magnet, even if an electromagnet is used, it can be used faster than conventional This method has the advantage of requiring a much smaller electromagnet than the electromagnet method.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view showing one embodiment of the present invention, FIG. 1(b)
2(a) is a perspective view of another embodiment; FIG. 2(b) is a side view of the same as the above; FIG. 3(c) is an explanatory view of the same as the above; FIG. A perspective view showing the principle, and FIG. 4 are explanatory views of the same operation. 1 is a hammer head, 2 is a fixed shaft, 3 is a shuttle, 4 is a linear motor, 5 is a bearing, 6 is a permanent magnet on the fixed side, 7 is a permanent magnet on the movable side, and 8 is an electromagnet. Figure 1 (b) (C) Figure 3

Claims (1)

[Claims] (1) A shuttle carrying a printing block is oscillated by a linear motor, and permanent magnets or electromagnets are fixedly installed in the printer body to face the permanent magnets fixed to the shuttle at both ends of the stroke of the shuttle. Line printer carriage mechanism.