JPH022021A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To prevent the generation of force exceeding proper pressure contact force in a head pressing spring by constituting the title printer so that a heat sink is also rotated when a head pressing member is rotated by the driving force of a drive mechanism and a thermal head is brought into contact with a platen under pressure or separated therefrom. CONSTITUTION:A thermal head 1 is prescribed so as not to be separated by a predetermined distance or more from a platen 3 by pressing the projection provided to a head pressing member 13 by a head pressing spring 14 to engage the same with the engaging piece 11c of a heat sink. When the thermal head 1 is separated from the platen 3, a cam 20 is rotated in a clockwise direction to rotate a plate B21 upwardly along a cam groove 20a by a pin 23 and a plate A17 is rotated upwardly by a pin 24. The plate A17 rotates to allow the head pressing member 13 to rotate upwardly. The head pressing spring 14 extends until the projection 15 of the head pressing member 13 strickes on the engaging piece 11c of the heat sink 11 and, the moment said projection 15 strikes the engaging piece 11c, the heat sink 11 is rotated upwardly. Therefore, the generation of force in the head pressing spring in necessary quantity or more can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer printer, and particularly to a liquid groove that presses or separates a thermal head from a platen.

[Prior Art] Fig. 4 is a side view showing a mechanism for pressing a thermal head against or separating it from a platen in a conventional thermal transfer printer disclosed in, for example, Japanese Utility Model Application Publication No. 59-110649. Head, (2) is a heat sink with thermal head (1) attached, (3)
is the platen, (4) is the ink sheet, (5) is the printing paper, (6) is the roller for conveying the ink sheet (4), (7)
is a pressing force release means for releasing the pressing force between the thermal head (1) and the platen (3), and the solenoid (7a
) and a plunger (7) connected to the thermal head (1).
b). (8) is a head pressing spring that applies a pressing force to the thermal head (1), (9) is an ink sheet supply roll, and (10) is an ink sheet take-up roll.

Next, the operation will be explained. Figure 4 shows the state during printing. In the figure, by rotating the platen (3) clockwise, the printing paper (5) and ink sheet (4) advancing from six directions are placed in the thermal head. (1)
After being heated and transferred at the pressure contact part of the platen (3),
The ink sheet (4) is sent in the B direction, and the printing paper (5) is sent in the C direction.

Next, when separating the thermal head (1) from the platen (3) in order to operate the printing paper (5) and ink sheet (4) individually, the solenoid (7a) is energized and the thermal head (1) is attached. The plunger (7b) connected to the heat sink (2) is sucked, overcomes the pressing force of the spring (8), and moves the thermal head (1) to the platen (
3) Pull it away.

With the thermal head (1) separated from the platen (3), move the ink sheet (4) and printing paper (5) to a predetermined position, and then press the thermal head (1) against the platen (3). In this case, if the solenoid (7a) is deenergized, the state shown in FIG. 4 will be achieved due to the pressing force of the spring (8).

[Problems to be Solved by the Invention] Since the conventional thermal transfer printer is configured as described above, the head pressing spring (8) that applies appropriate pressure to the thermal head (1) is connected to the heat sink (2) and the fixed part. The up-down movement of the thermal head (1) is directly controlled by the solenoid (7a), so when the thermal head (1) is separated from the platen (3), the head pressing spring (8) ) must be deflected from the state shown in Figure 4, and therefore the driving force for separating the thermal head (1) must be deflected to the required dimension in order to apply an appropriate pressing force to the thermal head (1). Since a force larger than that of the head pressing spring (8) is required, there is a problem in that the drive system or drive source thereof becomes expensive.

This invention was made in order to solve the above-mentioned problems, and provides a thermal transfer printer that does not generate a force in the head pressing spring that exceeds the appropriate pressing force of the thermal head when the thermal head is moved up and down. The purpose is to

[Means for Solving the Problems] A thermal transfer printer according to the present invention is provided with a thermal head that presses overlapping printing paper and an ink sheet against a platen, and transfers ink from the ink sheet to the printing paper. a heat sink rotatably supported so as to be able to move toward and away from the heat sink; a head holding member rotatably supported opposite to the heat sink so as not to be separated from the heat sink by more than a predetermined distance; and applying a pressure contact force to the thermal head. a head pressing spring; and a drive wave groove that is connected to the head pressing member and that positions the head pressing member with respect to the heat sink when the thermal head is in the pressing position and also releases the pressing force of the thermal head. When the head holding member is rotated by the driving force of the driving wave groove, the heat sink is also rotated together with the head holding member, so that the thermal head is pressed into contact with the platen or separated from the platen. be.

[Function] In this invention, when the head holding member is rotated by the driving force of the drive wave groove, the heat sink is also rotated together with the head holding member, and the thermal head is separated from the platen, and the head holding member is rotated by the subsequent driving force. When rotated in the opposite direction, the heat sink is also rotated in the opposite direction together with the head holding member and the thermal head comes into contact with the platen, so that the head pressing spring no longer generates a force that exceeds the appropriate pressing force of the thermal head.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a side view of the thermal head section showing a state during printing, FIG. 2 is a side view of the thermal head section showing a standby state, and FIG. 3 is a partial perspective view of FIG. The same reference numerals are given to the same or corresponding parts as those in , and the explanation thereof will be omitted. In the figure, (11) is a heat sink to which a thermal head (1) is attached, which includes a heat sink body (11a), a support part (11b) that supports this heat sink body (lla), and an engaging piece (11) that projects upward.
c) It consists of. (12) is a heat sink (11
) that rotatably supports the frame (not shown).
is rotatably supported. (13) is a holding member placed above the heat sink (11).
(12) is rotatably fitted. (14) is a head pressing spring inserted between the heat sink (11) and the head holding member (13), and (15) is the head holding member (13).
3) is pressed by the head pressing spring (14) and engages with the engagement piece (11C), and the heat sink [1
1), the head holding member (13) is restricted from being separated by a predetermined distance or more. (16) is a mounting side plate formed physically on the head holding member (13), (17) is a plate A rotatably attached to the mounting side plate (16) with a pin (18), and (19) is a plate A. (17) is a spring that biases clockwise, (20) is a thermal head (1
), and (21) is a plate B that relays the power of the cam (20), and is rotatably supported by a shaft (22). (23) is a pin fixed to the lower part of the plate B (21), and is engaged with the cam groove (20a). (24) is a pin fixed to the upper part of plate B (21), and is engaged with the recess (17a) of plate A (17).

Next, the operation will be explained. In Fig. 1, by rotating the platen (3) clockwise, the printing M (5) and the ink sheet (4) that have advanced from the direction are brought into pressure contact between the thermal head (1) and the platen (3). After being thermally transferred in the section, the ink sheet (4) moves in the B direction,
The printing paper (5) is sent in the C direction.

Next, when separating the thermal head (1) from the platen (3) in order to operate the printing paper (5) and the ink sheet (4) individually, the cam (20) is rotated clockwise (direction C). When the cam (2o) rotates in the C direction, the pin (23) moves along the cam groove (20a) to the plate B (21).
) upward (counterclockwise) and tighten the rough pin (24
) rotates plate A (17) upwards (counterclockwise). While rotating the plate A (17) slightly counterclockwise, move the head holding member (13) upward (counterclockwise).
Rotate to

Then, the head pressing spring (14) extends until the protrusion (15) of the head holding member (13) hits the engagement piece (llc) of the heat sink (11), and the protrusion (15) touches the engagement piece (llc).
lc), the head holding member (13) rotates the heat sink (11) upward (counterclockwise). The state in which the thermal head (1) is thus separated from the platen (3) is as shown in FIG.

With the thermal head (1) separated from the platen (3) in this way, after moving the ink sheet (4) and printing paper (5) to the predetermined positions, the thermal head (
1) to the platen (3), use the cam (20
) further clockwise in the E direction. Cam (20
) rotates in the E direction, the thermal head (1) is brought into pressure contact with the platen (3) as shown in Figure 1 in the reverse order of the above order of separating the thermal head (1) from the platen (3). .

In the above embodiment, the cam (20) is used as a drive source, and the drive mechanism including plate A (17) and plate B (21) is shown, but instead of the cam (20), another drive source such as a solenoid is used. The same effect can be obtained by using other means instead of the two plates (17) and (21) for the connection.

[Effect of the invention 1 As described above, according to the present invention, when the thermal head is moved up and down, the structure is such that the head pressing spring that applies pressing force to the thermal head is not bent more than the necessary 4°. This has the effect that the driving force for causing the thermal head to move up and down can be reduced, and an inexpensive device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of the thermal head section showing a printing state of a thermal transfer printer according to an embodiment of the present invention, FIG. 2 is a side view of the thermal head section showing a standby state, and FIG. FIG. 4 is a side view of the thermal head section of the conventional thermal transfer printer showing the state during printing. In the figure, (1) is the thermal head, (3) is the platen, (4) is the ink sheet, (5) is the printing paper, and (11) is the ink sheet.
) is the heat sink, (13) is the head holding member, (14
) is a head pressing spring, and (17) to (24) are drive units. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A platen that winds up the overlapping printing paper and ink sheet, and a thermal head that is in pressure contact with the platen via the printing paper and ink sheet rolled up on this platen, and that transfers the ink from the ink sheet to the printing paper. , a heat sink to which the thermal head is attached and rotatably supported so that the thermal head can move toward and away from the platen; and a heat sink rotatably supported opposite to the heat sink so as not to be separated from the heat sink by more than a predetermined distance. a head pressing member; a head pressing spring inserted between the head pressing member and the heat sink to apply pressure to the thermal head;
and a drive mechanism that is connected to the head holding member and that positions the head holding member with respect to the heat sink when the thermal head is in the pressure contact position, and also releases the pressure contact force of the thermal head, the drive mechanism When the head holding member is rotated by a driving force, the heat sink is also rotated together with the head holding member, so that the thermal head is pressed into contact with the platen or separated from the platen.