JPS62251173A - Printing head drive controller - Google Patents

Abstract

PURPOSE:To generate a low noise of the titled controller, by driving a DC motor by pulse energization. CONSTITUTION:If a positive pulse energization is applied to a DC motor 9 when a link pin 13 is at a position of 0 deg. in rotary angle, a drive gear 10 is rotated counterclockwise and a follower gear 11 is rotated clockwise. Thereby, the link pin 13 is moved to the position of 240 deg. in rotary angle along a guide groove 14. Following the leftward displacement of a link lever 16, a tensile coil spring 9 operates on a drive lever 5 and a printing head 3 is pressed onto a platen 2. The traveling speed of the printing head 3 is slow because of the pulse energization at an equal pulse interval and the collision noise produced when the link pin 13 collides against one end of the guide groove 14 becomes small. Further, if a negative pulse is applied to a DC motor 9 when the link pin 13 is at a position of 240 deg. in rotary angle, the gears 10 and 11 are rotated reversely. The lever 16 is displaced rightward and the printing head 3 is separated from the platen 2. The shock noise at that time when the pin 13 strikes against the guide groove 14, becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a print head drive control device applied to printers and the like.

[Conventional technology]

As conventional devices of this kind, there are those shown in Japanese Patent Laid-Open No. 56-27380 and Japanese Patent Laid-Open No. 58-67490.

These use a solenoid as a drive source for the print head, which will be explained with reference to FIGS. 5(A) and 5(B). In the figure, (1) is the device main body, and (2) is the device main body (1).
(3) is a print head such as a thermal head rotatably supported on a shaft (4) so as to face the front surface of the platen (2); (5) is a print head such as a thermal head rotatably supported on a shaft (4);
), the head drive lever (6) is hung between the device body (1) and the head drive lever (5), and applies a spring force to the print head (3) toward the platen. Tensile carp that energizes! Chill with a spring.

(7) is a solenoid fixed to the device body (1), and the tip of the plunger (7a) is connected to the head drive lever (
5). (8) is printing paper such as photosensitive paper.

In the above configuration, when the solenoid (7) is powered off, the plunger (7a) is released and the head drive lever (5) is rotated clockwise by the spring force of the tension coil μ spring (6). . As a result, as shown in FIG. 5(A), the print head (3) passes through the print paper (8) to the platen (2).
Printing operation is possible by pressing against the front surface of the printer.

When the solenoid (7) is energized, the plunger (7a) is attracted against the spring force of the tension coil μ spring (6), the head drive lever (5) rotates counterclockwise, and as a result, the print head ( 3) is attached to the platen (2) as shown in Figure 5 (B).
turn away from

[Problem that the invention seeks to solve]

In the above conventional system, the print head (3) is driven away.

Because it is configured with a solenoid (7) and a lever (5),
When the solenoid is closed and the power is cut off, the print head (3) impacts the platen (2) due to the spring force, producing a loud collision sound, and even when the solenoid (7) is energized, the plunger (7a) makes a suction sound. There was a problem with the noise.

The present invention was made in order to solve the above-mentioned problems of the conventional device, and an object of the present invention is to provide a print head drive control device that can significantly reduce noise.

[Means for solving problems]

The print head drive control device according to the present invention includes a crank installed in the main body of the device, driven by a DC motor, and having a rotation range in forward and reverse directions that is restricted in accordance with the platen pressure contact position and the platen separation position of the print head. The mechanism and the head drive lever are connected by a link lever, and the upper and lower DC currents are driven by pulse energization at equal pulse intervals.

[Effect]

In this invention, since the drive source of the print head is a DC motor, there is less noise generated by the operation of a solenoid, and because the DC motor is energized with pulses at equal pulse intervals, rapid increases in speed are suppressed. The moving speed of the head in the vicinity of the platen pressure contact position and the platen separation position is slow, and the generation of noise is effectively prevented.

[Embodiments of the invention]

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

FIGS. 1(A) and 1(B) show an example of a print head drive control device according to the present invention, and the same parts as in the conventional one are given the same reference numerals and explanations are omitted. , (9) is a forward and reversible DC motor attached to the device body (1) (io) is a driving gear fixed to the motor shaft of the DC motor (9), (11)
is a driven gear that is supported by the device main body (1) via a support shaft (12) and meshes with the driving gear (10). (13) is a link pin that protrudes and is fixed to both the inner and outer surfaces of the driven gear (11), and is inserted into the arcuate guide groove (14) provided on the device body (1) side, As shown in the figure, it is set to be movable within a rotation angle range of 06 to 240 degrees, and forms a crank mechanism (15) together with the driven gear (11) and the like. (16) is the crank mechanism (15) and one end (5) of the head drive lever (5).
The link lever sb is connected between the a) side and the one end (16a) side is rotatably pivoted to the link pin (13), and the #1 side is a long hole (17) formed in the center part. The drive pin (18) on the head drive lever (5) side is inserted into the head drive lever (5). The tension coil μ spring (6) is attached to the drive pin (18
) and the other end (16b) of the link lever (16). Reference numeral (19) is a motor drive circuit which applies pulse current to the DC motor (9) at equal pulse intervals. In this example, when the print head (3) is brought into pressure contact with the platen (2), the same energizing pulse is applied from startup to tilting as shown in Figure 3 (A), and the print head (3) is pressed against the platen (2). When moving the motor away from the platen (2) side, as shown in Figure 4 (A), the setting is such that pulse energization is applied when the motor is started, then it is temporarily interrupted, and supplementary energization is performed at the end. Next, the operation of the above configuration will be explained.

Now, the position of the link pin (ia) when the print head (3) is separated from the platen (2) (Fig. 1 (B)) corresponds to the rotation angle θ°, and the print head (3) is separated from the platen (2). (2
) The position of the link pin (13) when it is in pressure contact with the
Assume that the diagram (A) corresponds to a rotation angle of 240°.

Therefore, when the link pin (13) is at the rotation angle θ° shown in FIG. 1(B), if a positive energization pulse shown in FIG. 3(A) is applied to the DC motor (9), the driving gear ( 10
) rotates counterclockwise, and the driven gear (11) rotates clockwise. Therefore, the link pin (13) has a guide groove (
14) to a position at a rotation angle of 240° in FIG. 1(A), and the link lever (16) is also displaced to the left.

Along with this displacement of the link lever (16) to the left,
Tensile carp! The spring force of the spring (6) is applied to the head drive lever (5).
), the print head (3) is attached to the platen (2).
Press it against the front of the

At this time, the load torque and rotational speed of the DC motor (9) become the curves Ta and Sa in Figure 3 (B), respectively.0 When the DC motor (9) is driven with a continuous current, the speed In other words, the moving speed of the print head (3) increases rapidly, making it difficult to alleviate the impact noise on the platen (2). However, according to the above configuration, the print head (3) ) is also slow, and the impact of the link pin (13) hitting one end (240° position) of the guide groove (14) is also reduced, and the impact noise is significantly reduced.

Also, the link pin (13) has a rotation angle of 24 in FIG. 1(A).
When the DC motor (9) is at the 0° position and a negative bus (μ) as shown in Fig. 4 (A) is applied to the DC motor (9), the driving gear (10) rotates clockwise due to the bus (μ) at startup. , driven gear (11)
rotates counterclockwise, and the link lever (16) is slightly displaced to the right.

Thereafter, after the DC motor (9) rotates due to inertia, the link pin (13) is positioned at a rotation angle of 0' at the final auxiliary energization bus, and the print head (3) is separated from the platen (2).

At this time, the load torque and rotational speed of the DC converter (9) become curves Tb and Sb in FIG. 4(B), respectively. At this time, the separation speed of the print head (3) is slow, and the link pin (13) is at the other end of the guide groove (14) (
The impact hitting the 0@ position) will also be smaller. Of course, during the separation operation of the print head (3), the DC motor (9) may be energized without interruption at equal pulse intervals from the initial stage to the final stage.

[Effects of the Invention] As described above, in this invention, the rotational force of the DC motor is transmitted to the head drive lever via the crank mechanism and the link lever, and the DC motor is driven by pulse energization at equal pulse intervals. Accordingly, it is possible to provide a print head drive control device that can contribute to reducing noise by slowing down the speed of the print head during press contact and separation operations of the print head with respect to the platen.

[Brief explanation of drawings]

1A and 1B are configuration diagrams showing an example of the print head drive control device according to the present invention in different operating states, FIG. 2 is an explanatory diagram of the moving range of the link pin in the same device, and FIG. Figure (A) is a waveform diagram of the pulses applied to the DC motor when the print head is in pressure contact, and Figure 3 (B) is the same figure (
FIG. 4(A) is a characteristic diagram of the rotational speed and load torque of the DC motor when the print head is pressed into contact with the print head corresponding to FIG. 4(A), and FIG. Figure 4 (B) is a characteristic diagram of the rotational speed and load torque of the DC motor when the print head is separated, corresponding to Figure 4 (A);
FIGS. 5A and 5B are configuration diagrams showing a conventional print head drive control device in different operating states. (11... device body, (2)... platen, (3)
...Print head, (5)--Head drive lever s
(61"・Spring member% (91"・DC motor% (15)
... Crank mechanism s (16) ... Link lever s (19) ... Motor drive circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A platen installed inside the device body, a print head arranged opposite to the front surface of the platen, and a rotatably supported shaft inside the device body to connect the print head to the platen pressure position and the platen. a head drive lever for displacing the print head between the separation position and the separation position; a spring member for applying a spring force to the print head in the direction of pressure contact with the platen via the head drive lever; a DC motor installed in the apparatus main body; A crank mechanism driven by a motor and whose rotation range in forward and reverse directions is restricted in accordance with the platen pressure contact position and platen separation position of the print head, and a link connected between the crank mechanism and the head drive lever. A print head drive control device comprising: a lever; and a motor drive circuit that energizes the DC motor with pulses at equal pulse intervals.