JPS593159B2 - small printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a type wheel selection device that is activated by a print command, performs a series of printing operations, and stops at a predetermined standby position.

Regarding small size printers. An object of the present invention is to reduce power consumption by shortening the time during which the electromagnet is energized.

Figure 1 shows a conventional type wheel selection type compact printer.
2 is a printer drive motor, 2 is an intermittent drive gear 5 having teeth 3 and a notch 4 with the diameter of the tooth bottom on a part of its circumference, and 5 is a tooth 6 and a notch similar to the intermittent drive gear 2. 8 is a type wheel shaft which rotates in unison with the intermittent gear 5, and 10 type letters are placed on the shaft 8 by a type wheel character position detector 13 consisting of a slit plate 10, an LED II, and a phototransistor 12. The character position on the ring 9 is detected, a type wheel selection claw 14 is operated to select the type wheel 9, and printing is performed by pressing the printing paper 15 with a printing roller 16. IT is the return spring of the type wheel 9, 18A and B are the rotation directions, 20 is the magnet installed in the intermittent drive gear 2, 21 is the reed 15, and the magnet 20
, a stop signal is obtained from the reed switch 21 to turn off the power to the drive motor 1. FIG. 2 shows a time chart of a conventional small printer, which will be explained with reference to FIGS. 1 and 2. The printer drive motor 1 is activated by the print command, the intermittent drive gear 2 starts rotating, the teeth 3 of the intermittent drive gear 2 and the teeth 6 of the intermittent gear 5 start to mesh, and the intermittent gear 5 moves in the direction of the arrow. It rotates in the direction of 18A while winding up the return spring 17. When the intermittent gear 5 rotates, the type wheel 9 also rotates, the type wheel character position detector 13 outputs a timing pulse 25, and when the type wheel selection signal o is output from an LSI such as a calculator, the type wheel 9 shown in Figure 2 As with the selection signal o, the period from timing pulse o to 1 is fully energized (in detail, the period from timing pulse o to 1 is completely energized.
0), characters are selected by a selection mechanism that operates the type wheel selection claw 14. When the intermittent drive gear 2 continues to rotate and character selection is completed, the intermittent drive gear 2 and the intermittent gear 5
is disengaged, and the intermittent gear 5 is locked in a state where the return spring IT is wound up due to the uncut portion 19 of the intermittent drive gear 2. At this time, the printing roller 16 is rotating in synchronization with the intermittent drive gear 2, and prints on the printing paper 15 by rolling over the type on the selected type wheel 9.

When printing is completed, the intermittent gear 5 is locked and the intermittent drive gear 2
It ends due to the notch 4 of the arrow 1 due to the return spring 17.
It rotates in the direction of 8B and returns to the standby position. At the same time, the type wheel 9 also returns to its standby position. Paper feeding is performed by a paper feeding mechanism after printing is completed. Considering the printer's mechanical load, motor inertia, etc., a stop command is generated using the magnet 20 on the intermittent drive gear 2, which rotates once per printing stroke during paper feeding or back and forth, and the reed switch 21 installed on the printer frame, etc. In response to this stop command, the printer drive motor 1 is de-energized, electrically braked, and abruptly stopped, putting all printer mechanisms in a standby state. The print command causes the next printing operation, and printing is performed repeatedly. As mentioned above, in the conventional small printer, only the character position on the type wheel is detected by the type wheel character position detector 13, and the stop signal for the drive motor is obtained from a signal from another stop position detector.

The present invention reduces the number of conventional two-system signals, detects the position of the type wheel based on the rotation speed detection signal of the drive motor, obtains a signal to stop the drive motor, and changes the type wheel selection signal from time to time. Divide it to shorten the energization time. Third
Figures 4 and 5 show one embodiment of the present invention, and Figures 3 and 5 are time charts, and Figure 4 shows the counter for detecting the character position of the type wheel and the drive motor stop. An example of a circuit for a position detection counter is shown. 3, 4, and 5, the drive motor 1 (shown in FIG. 1) is energized and started in response to a print command, and a counter start signal is sent to a gear (intermittent drive gear 2) that rotates once per print line. ) or type wheel 9
A signal is obtained from a mechanical switch contact, a reed switch and a magnet, a photodetector, etc. from a part that rotates in coincidence with or in synchronization with the counter start signal, and the rotation speed detection signal of the drive motor after the counter start signal (Fig. 1, drive motor 5 The output signal of the rotation speed detector (tachogenerator) directly connected to the motor shaft 22 is sequentially counted by the counter COUNT, and the signal at the character position on the type wheel 9 is detected. ′::! ;Mayuzumi::↑4
Obtain 1,...

Among these m pulses, the electromagnet is controlled by n pulses (m>n) to select a character on the type ring 9. As shown in FIG. 2, when a 0 type wheel selection signal is output from an LSI such as a calculator, conventionally the character position 0 on the type wheel 9 is
The timing signal at the character position was fully energized.

This detects the character position of the type wheel 9 using the type wheel character position detector 13.
Because the type was taken out from the type wheel spindle 8, which rotated at a low speed, only full current could be applied. However, as shown in Figure 5,
In order to obtain a signal of the character position on the type wheel 9 with a rotation speed detector from the drive motor 1 which rotates at high speed according to the present invention,
The motor rotation speed detection signal is counted, the type wheel selection signal is time-divided, and the energization is made shorter than the full energization to reduce the power consumption. The operation of the printer is similar to that of the conventional printer shown in FIG. 1, so a description thereof will be omitted.

When a character is selected and printing is completed, the rotation speed detection signal of the drive motor 1 after the counter start signal is sequentially counted by the counter COUNT so that the printer stops at the standby position, and a counter COUNT is used to stop the drive motor 1. Obtain stop command signal COUNT8. In response to this stop command, the drive motor 1 is de-energized and electrically braked to a sudden stop, putting all printer mechanisms in a standby state. The print command causes the next printing operation, and printing is performed repeatedly. When continuous printing commands are received from an LSI such as a calculator, the drive motor 1 may be continuously energized, ignoring the stop command signal. The rotation speed detection signal of drive motor 1 is motor 1.
The larger the number of pulses during rotation, the more accurately the characters on the type wheel 9 can be selected. In addition, the drive motor is set so that an integral multiple of the pulse of the rotation speed detection signal matches the timing between the characters on the type wheel 9 so that the rotation speed detection signal of the drive motor 1 and the timing of the characters on the type wheel 9 match. It is necessary to consider reducing the number of teeth from 1 to the intermittent gear 5. Further, by using the rotation speed detection signal of the drive motor 1 for rotation speed control, a stable rotation speed of the drive motor can be obtained. According to the present invention, the position of the type wheel of the printer is detected based on the drive motor rotation speed detection signal of the small printer, a stop signal for stopping the drive motor is obtained, and the type wheel selection signal is time-divided. Since the energization time is shortened, electric power can be reduced, an expensive character position detector is not required, and a stable rotational speed can be obtained by controlling the rotational speed of the drive motor using the rotational speed detection signal.

Therefore, it is possible to provide a small, high-performance, highly reliable, and low-cost printer.

[Brief explanation of the drawings] Figure 1 shows a conventional type wheel selection type compact printer.
2 is a printer drive motor, 2 is an intermittent drive gear, 5 is an intermittent gear, 9 is a type wheel, 13 is a character position detector, and 22 is a rotation speed detector.

Claims (1)

[Scope of Claims] 1. A type wheel selection type printer that is activated by a printing command, performs a series of printing operations, and stops at a predetermined standby position, comprising: a drive motor that rotates the type wheel; and a drive motor connected to the drive motor. a tacho generator that generates a pulsed rotational speed detection signal; a counter start signal detector that starts counting the rotational speed detection signal; a type wheel selection signal for respectively detecting the position of the type characters, a selection pawl that engages with the type wheel to select a type, and an electromagnet that operates the selection pawl; n of the pulses (m>n
A small printer, characterized in that the electromagnet is controlled with a pulse width of ).