JPS58148786A - Prevention system of rebound of printing head - Google Patents

Abstract

PURPOSE:To effectively reduce the rebound of a printing head by providing a system in which the normal rotation drive time is shortened and a given width of pulse is given at intervals for a mechanism by which the printing head is allowed to come near or retracted by normally by reversely turning on a DC motor. CONSTITUTION:A DC motor 26 is driven by normal or reverse turning either by turning on transistors 21 and 24 or turning on transistors 22 and 23, and by this a printing head is allowed to come near or retracted from a printing position. In this case, the normal-turning drive time of the DC motor 25 is set up shorter than all displacing time of the printing head and a given width of pulse (b) is added to make it coincide with time points related to all displacement of the printing head. Thus, the rebound vibration of the head can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a print head of a printer, and a head carrier on which the print head is mounted. 1) Reducing the rebound that occurs in a mechanism that approaches the printing position and retreats from the printing position by forward and reverse rotation of the DC motor (1) This relates to a method for preventing rebound of the print head.

(2) Conventional technology and problems Conventionally, in order to displace the print head in accordance with the rotation of the feed shaft of the head carrier, printers have used a system in which a direct current motor rotates forward or reverse to approach the printing position and retreat. It is often used.

FIG. 1 shows the head approach and evacuation of Tonohakashi's printer.

For example, the print head 1 having the dot printing section 2 is moved onto the head carrier 4 on the eItL feed shaft 5. The print head 1 is displaced around the feed shaft 5 and reaches a printing position, and dot printing is performed on the paper on the platen 60 surface. In order to perform this operation, a block 7 having a shaft 6 fitted into a hole at the rear end of the head carrier 4 is provided, and an eccentric shaft 8 which is perpendicular to the shaft 6 and has a gear 9 at the other end is provided on this block.
is provided so that it can be rotated freely. This gear 9 is driven forward and reverse by a DC motor 11 directly connected to an interlocking gear 10.

(2) That is, the eccentric shaft 8 rotates left and right due to the forward and reverse rotation of the DC motor 11, and the block 7 moves up and down, and as a result, the print head 1 rotates as the feed shaft 5 rotates. , the dot printing section 2 approaches the platen 6, printing is performed at the printing position, and then begins its retreating process.

As the drive circuit for the above DC motor, an H-type circuit shown in FIG. 2 is used. That is, the d-blade transistor 21.23 and the transistor 2z24 are connected in parallel between +24V and ground, and the DC motor 25 is connected between the connection points of both circuits. Control these four transistors, transistor 21
．． Normal rotation or reverse rotation is performed depending on whether transistors 24 or 22 and 23 are turned on.

In this case, the problem is that after the print head reaches the printing position with respect to the platen 3 and the operation is completed, vibration occurs due to rebound. If this exists, the time for evacuation will be delayed and high-speed operation will be delayed.
Correct.

As a countermeasure against such rebound, it was possible to reduce the rebound to a certain extent by setting the normal drive time of the DC motor to be shorter (by 6 seconds) than when the print head is displaced. However, this alone was not enough.

(3) Object of the Invention The object of the present invention is to provide a print head rebound prevention method that effectively reduces the rebound of the print head when the print head of a printer approaches and retreats from the printing position by forward and reverse rotation of a DC motor. It is to be.

(4) Structure of the Invention In order to achieve the above-mentioned object, the print head rebound prevention system of the present invention operates by rotating the print head of a printer in the forward and reverse directions of a direct current motor on the feed p-axis rotation of the head carrier to which it is attached. ) In the proximity retraction mechanism for the print head that approaches and retracts from the print position, the forward rotation g excitation time of the DC motor is set to be shorter than the total displacement time of the print head, and the g excitation time of the forward rotation of the DC motor is set to be shorter than the total displacement time of the print head. Additionally, a means for adding a predetermined width of re-drive is provided to reduce the rebound of the print head.

(4) (5) Embodiments of the Invention In the present invention, rebound can be reduced simply by improving the drive waveform of the normal rotation of the DC motor 25 shown in FIG. The structure consists of transistors 21 and 24 in Figure 2.
The driving time for turning on is set to be shorter than the operational displacement time of the print head, and a drive pulse of a predetermined width is applied when the print head reaches the printing position to cancel out the vibration caused by rebound. It is. Specifically, such a waveform forming circuit is easily possible using conventional techniques.

FIGS. 6(a) to 6(f) show operating waveforms of an embodiment of the present invention in comparison with a conventional example.

Figures (a) and (b) show the conventional example (A) of DC motor 2.
5 driving time.

This figure shows the operating waveforms of the print head. Figure (a)
The driving time is the entire displacement time of the print head, and when the print head is stopped, a rebound waveform (2) occurs in the operating waveform shown in FIG. 2(b).

This delays the retraction point of the print head.

On the other hand, Figures (c) and (d) show the drive time of the DC motor 25 and the operating wave (5) shape of the print head in the actual image example (B1) of the present invention. This is shown in response to the following.

The driving time in the same figure (C) is 1 from the total displacement time of the print head.
In this case, a pulse O of a predetermined width is applied after a predetermined interval (with a short fall at @ ), but in this case, as shown in the operation waveform of the same figure (d), the rebound vibration @ is There will be times when you can't do it.

Therefore, in the same figure (e), (a is another embodiment of the present invention)
B2) shows the drive time of the DC motor 25 and the operation waveform of the print head. In this case, by appropriately setting the falling edge of the driving time shown in (e) and the position and pulse width of the pulse 6 to be added next, the operation waveform shown in (f) of the same figure can be obtained. So that rebound vibration can be completely eliminated.

(6) As described in detail, according to the present invention, the driving time of the direct current motor in the normal rotation is set to be shorter than the total displacement time of the print head, and pulses of a predetermined width are set at intervals. The simple configuration of adding a . It will be helpful.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the impact retraction mechanism of a printer to which the present invention is applied, Fig. 2 is a drive circuit thereof, and Figs. 6 (a) to (f) show operating waveforms of the present invention in comparison with a conventional example. Reeds in the drawing,
In the figure, 1 is a print head, 2 is a printing tip 1.6 is a platen, 4 is a head carrier, 5 is a feed shaft, 6 is a shaft, 7 is a block, 8 is an eccentric shaft, 9.10 is a gear, 11. 25 is a DC motor, and 21 to 24 are power transistors. Patent applicant Chojutsu Co., Ltd. Sub-agent Patent attorney 1) Yoshishige Saka (7) Figure 1 Figure 2

Claims (1)

[Claims] In a print head proximity and retraction mechanism that moves the print head of a printer close to and retracted from a print position by forward and reverse rotation of a DC motor according to the rotation of the axis of the head carrier to which it is attached, the DC motor is driven in the forward direction. The present invention is characterized in that the time is set to be shorter than the total displacement time of the print head, and means is provided for adding a re-drive of a predetermined width at a time point related to the total displacement of the print head, thereby completely reducing the rebound of the print head. Print head rebound prevention system.