JPH0525674B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intermittent printing device in which type is stationary during printing.

Since the printing speed of conventional intermittent printing devices was slow, it did not really matter when the next printing hammer or type wheel started driving the carriage after printing with the printing hammer.

However, since methods of controlling printing devices using microprocessors and the like have been introduced, printing speeds have increased dramatically. In particular, when bold printing is performed using a petal-shaped type wheel, contact between the printing hammer and the type wheel causes variations in printing and damage to the type wheel. The reason for this is that the printing hammer rebounds after printing, and furthermore, this rebound varies depending on the printed characters.

The present invention solves the above-mentioned problems of the prior art, and is a printing device that prints by pressing a type wheel mounted on a carriage onto a recording medium together with an ink ribbon. A printing hammer having a plurality of holes in a direction crossing the direction of reciprocating motion for printing, and a light emitting element and a light receiving element provided on both sides of the plurality of holes along the reciprocating direction, a detection means for detecting the reciprocating motion of the printing hammer by receiving light from the light emitting element through the hole and by the light receiving element and outputting an output signal; and in response to input of the output signal from the detection means. a timer means for outputting an output signal to the outside indicating that a predetermined time has elapsed since the input of the latest output signal from the detection means; A printing device characterized in that it has a control means that detects that a rebound amount of a hammer is less than a certain amount and cancels the prohibition of the operation of the type wheel or the carriage to enable the next printing. The purpose is to

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a printing hammer 1 moves in the direction of a type wheel 7 when a hammer coil 2 is energized, and moves along with an ink ribbon 8 to a type wheel 7.
is pressed against the platen 9 and printed on the printing paper.

3 is a light emitting diode (LED) printing hammer 1
When the hammer 1 is operated, light passes through the hole 5 provided in the hammer 1 and can be received by the phototransistor 4. The hole 5 is designed so that it can receive light whenever the hammer 1 comes into contact with the type wheel due to rebound.

Incidentally, it is preferable to have a plurality of passage holes 5 in order to reduce errors caused by foreign matter or the like.

FIG. 2 shows a printing hammer drive circuit as an example of the present invention.

The hammer printing command turns on the transistor 12 through the inverter 11, and the printing hammer coil 13
Excite. Also, the first edge of the output of the inverter 11 sets the flip-flop 14. Further, the output lights up LED3.

When the printing hammer 1 begins to move, the light passing hole 5 shown in FIG. When the output is 0, it is an inhibit signal that tells a CPU (not shown) not to transmit the next HMR signal. When printing is finished and the rebound of the printing hammer settles below a certain amount, the trigger signal to the one shot 15 is cut off, and after τ time from the last trigger, the output of 15 becomes 1, and at the same time, the inhibition to the CPU is released and the flip-flop is activated by the output of the NAND gate. 14. Therefore, LED3 is also turned off.
This allows the CPU to immediately send the next hammer drive signal HMR in the case of bold printing, etc. FIG. 3 shows a timing waveform diagram explaining the above operation.

4 and 5 show other examples of the invention. As in the previous example, when the printing hammer 1 starts to move, the light passing hole 5 shown in FIG. The output is sent to the NAND gate 17, and during this time, even if the drive signal WMENBL for the type wheel motor is issued, the drive of the motor is not started. When printing is completed and there is no possibility that the rebound of the printing hammer 1 will come into contact with the type wheel, the trigger signal to the one shot 15 is cut off, the output of the one shot 15 returns to 1 after a time τ, and the type wheel motor is immediately activated by the type wheel motor drive signal. move.

At this time, the flip-flop 14 is simultaneously reset, the LED 3 stops lighting, and preparations are made to receive the next printing hammer signal.

FIG. 5 shows a diagram of a series of these operations.

This method can also be applied to a carriage drive motor.

As explained above, according to the present invention, it is detected that the rebound amount of the printing hammer has become less than a certain amount after a predetermined period of time has passed since the reciprocating movement of the printing hammer is no longer detected, and the printing wheel is rotated. Alternatively, the prohibition of carriage movement can be canceled to enable the next printing, so there is no need to wait for the rebound of the hammer to completely stop after the printing hammer is driven, and until the type wheel or carriage moves for the next printing. This eliminates wasted time and increases printing speed with stable printing quality. Further, it is possible to prevent deterioration in printing quality or damage caused by contact accidents between the printing hammer and the printing wheel.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the present invention, Fig. 2 is a diagram of its circuit example, Fig. 3 is its operating waveform diagram, Fig. 4 is another circuit example diagram, and Fig. 5 is its operating waveform diagram. . 1... Hammer, 3, 4... Light emitting/receiving element, 5...
Hole, 14...flip-flop, 15...one shot circuit.

Claims (1)

[Scope of Claims] 1. In a printing device that prints by pressing a type wheel mounted on a carriage together with an ink ribbon onto a recording medium, the direction of reciprocating motion for pressing the type wheel to perform printing and includes a printing hammer having a plurality of holes in intersecting directions, and a light emitting element and a light receiving element provided on both sides of the plurality of holes along the reciprocating direction, and transmitting light from the light emitting element through the holes. detecting means for detecting the reciprocating motion of the printing hammer by receiving light with the light receiving element and outputting an output signal; a timer means for outputting an output signal to the outside indicating that a predetermined time has elapsed since the input of the output signal from the timer means; and a rebound amount of the printing hammer is less than or equal to a certain amount in response to the input of the output signal from the timer means. a control means for detecting the type wheel or the carriage to cancel the prohibition of the operation of the type wheel or the carriage to enable the next printing.