JPS5919825B2 - Serial printer type selection mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a type selection mechanism for a serial printer, and more particularly, in a serial printer in which type is selected by rotating and raising and lowering a print wheel with type characters provided in the upper and lower stages, the print wheel is moved up and down via a cam or the like. The present invention relates to a rotary magnet type type selection mechanism.

Conventionally, this type of type selection mechanism has been known to use a servo motor or pulse motor as a power source, and another to use a magnet or solenoid. This has the disadvantage that the control circuit and control circuit are inevitably expensive, resulting in poor cost performance.

On the other hand, when using a magnet or solenoid, it is necessary to keep the solenoid energized when holding it on one side, which inevitably increases the temperature of the solenoid and wastes power, making it difficult to downsize the solenoid. On the other hand, since the reprint wheel is positioned by linear motion, it is not possible to speed up the selection motion due to repounding, and control circuits for position detection etc. are required and are expensive. Nakatsuta. In view of these conventional circumstances, the present invention aims to solve the above-mentioned drawbacks by combining the advantages of motors and magnets by using a rotary magnet that rotates at a fixed angle. A rotary magnet incorporating a permanent magnet is operated by changing the direction of rotation using positive and negative pulsed excitation currents to select the type column, and the magnetic force of the permanent magnet is used to select either the upper or lower type column selection position. The present invention provides a compact, high-speed, highly reliable, and highly economical rotary magnet type type selection mechanism that has a self-holding structure.

That is, the rotary magnet type type selection mechanism of the present invention uses a rotary magnet with a permanent magnet built into the rotor as a drive source solenoid that moves the print wheel up and down via an eccentric cam, and uses two stopping points of the eccentric cam. It is a mechanical dead point, and the rotary magnet is self-retaining by itself and mechanically. Therefore, the effects of vibrations on the print wheel and its related parts are completely eliminated, and high-quality printing is possible. Furthermore, the control circuit not only does not require position detection, but also rotates in a specified direction using either positive or negative pulsed excitation current, making it inexpensive, reliable, and high-performance. The invention provides many advantages. Next, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the print wheel 1 is of a known type having a large number of flexible type fingers with letters arranged in upper and lower levels, and a slide sleeve 2 fixed to its underside has a circumferential groove driven knob. The output roller 3 is slidably engaged with the input long hole groove, and the roller of the eccentric cam 5 directly connected to the rotary magnet 6 is similarly slidably engaged. The slide sleeve 2 engages concentrically with the output shaft of a servo motor 8 that rotationally drives the print wheel 1 for type finger selection and is slidable in the vertical direction, that is, in the direction of the motor shaft, and is also engaged by the motor shaft. It is rotationally driven via a fixed torque piece 9. That is, type selection on the print wheel 1 is performed by the rotational movement of the servo motor 8 transmitted to the slide sleeve 2 via the torque piece 9, and the rotational drive of the rotor of the rotary magnet 6 by the eccentric cam 5.
and the lifting motion converted by the driven joint 3. The printed characters positioned by these two mutually independent selection operations are struck from the back by a print hammer 10 and printed on a printing paper 13 on a platen 12 via an ink ribbon 11. This printing operation is basically known. Next, among the character selection operations, character selection by raising and lowering the print wheel 1 will be explained with reference to FIG.

Reference numeral 6 denotes a constant angle rotary magnet in which a permanent magnet 14 magnetized in the radial direction is incorporated into the rotor 7.
is an eccentric cam directly connected to the rotor 7, and 3 is a driven joint.
When an excitation current flows through the rotary magnet 6, the rotor 7 rotates in the corresponding direction, and the magnetic polarity of the iron core 16 caused by the internal coil 15 and the permanent magnet 1 incorporated in the rotor 7 rotate.
4 is magnetic. It stops at a balanced position. Here, even if the excitation current is cut off, the rotor is self-held by the force of the permanent magnet 14. Also, at this time, the rollers of the eccentric cam 5, which are freely sliding in the elongated groove 4 of the driven joint 3, are stopped at mechanical dead centers 17 and 18, so that the external part other than the rotation of the rotary magnet qt6 Under load, it will not be able to slide and will be in a self-holding state mechanically. This state is one type selection. When the other character stage is selected, the polarity of the excitation current is reversed, so that the rotor 7 of the rotary magnet 6 rotates in the opposite direction and similarly enters a self-holding state. When the movement direction command shown in FIG. 3 is received, the drive circuit applies an excitation current in the specified direction to the rotary magnet 6 to rotate the rotor 7 in the specified direction.

The output movement of the rotary magnet 6 is performed linearly, but the print wheel 1 and slide sleeve 2 are converted into non-linear movement by a cam mechanism, and at the stopping point there is almost no change with respect to the rotation of the rotary magnet. Needless to say, since there is no problem, positioning accuracy is improved, printing quality is improved, and reliability is improved. As is clear from the above explanation, the type column selection mechanism of the present invention can select and self-hold the upper and lower type columns by simply passing positive and negative pulsed currents through the excitation coil of the rotary magnet. , there is no wasted power consumption, vibration of the print wheel and its related parts is prevented, so the stopping characteristics are good, and with extremely high cost performance, it is easy to speed up selection and improve reliability. It has many advantages such as:

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a partial front view, and FIG. 3 is a diagram showing movement command pulses, applied current, rotor movement, and print wheel movement. . 1...Print wheel, 2...Slide sleeve, 3...Reservation joint, 4...
Elongated hole groove of driven joint, 5... Eccentric cam, 6...
...Rotary magnet, 7...Rotor, 8
... Servo motor, 9 ... Torque piece, 10 ... Print hammer, 11 ...
・Ink ribbon, 12...Platen, 13...
...printing paper, 14...permanent magnet magnetized in the radial direction, 15, 16...coil} and its iron core, 17...when lower row is selected Cam dead center, 18...Cam dead center when upper stage is selected.

Claims (1)

[Claims] 1. A serial printer that selects type by rotating and raising and lowering a print wheel that has type in two stages, upper and lower, has a rotary magnet, a cam that is directly connected to the rotor, and a driven node of the cam, and a positive and negative pulse pattern is applied to the rotary magnet. Each time an excitation current of A type selection mechanism characterized by self-holding together with a permanent magnet.