JPH02249656A - Thermal head pressure contact device in thermal transfer recording device - Google Patents

Abstract

PURPOSE:To obtain an inexpensive rapid pressure contact device operated noiselessly by moving an arm member to a platen engaging or separating position by the cam fixed to a platen shaft and pressing and bending a leaf spring at the engaging position to bring a thermal head into contact with a platen under pressure and pressing the head at the separating position to separate the same from the platen. CONSTITUTION:In a pressure contact device, when a cam follower 7 is engaged with the upper dead point of a cam 3, an arm member 5 is revolved in a counterclockwise direction and a spring engaging member 8 presses a spring holding member 14 to the left and a leaf spring 18 is curved downwardly to push down the upper surface of a thermal head. By this mechanism, the head 2 is revolved in the counterclockwise direction to be engaged with a platen 1. When the cam follower 7 is engaged with the lower dead point of the cam 3, the arm member 5 is revolved in the clockwise direction and the spring engaging member 8 is spaced apart from the holding member 14 and the leaf spring 18 extends at the curved part thereof to be spaced apart from the upper surface of the head 2. At the same time, the engaging piece 10 of a head engaging member 9 pushes down the upper surface of the head 2. The head 2 is revolved in the clockwise direction by this pushing-down action to be separated from the platen 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal head press-contacting device for a thermal transfer recording device, which includes a platen and a thermal head that engages with and disengages from the platen.

2. Description of the Related Art A typical example of a conventional thermal head pressure welding device is shown in FIG. 4, and will be described below.

2I is a platen, 22 is a thermal head, 23 is a spring for pressurizing the thermal head 22, 24 is a support member provided on the thermal head 22 to support a roller 25, and an eccentric cam 26 is provided opposite the roller 25. The eccentric cam 26 is rotated by an opening/closing motor 27. 28 indicates a leaf spring.

Problems to be Solved by the Invention In the conventional device as described above, the thermal head 2
2 from the platen 21, the motor 27 is operated to rotate the eccentric cam 26, and when the roller 25 engages at the top dead center, the thermal head 22 is moved upward against the pressing force of the spring 23. When the eccentric cam 26 rotates and the roller 25 engages at its bottom dead center, the thermal head 22 moves downward due to its own weight and the pressing force of the spring 23.

This device requires the opening/closing motor 27 installed separately to move the thermal head 22 as described above, and in addition, the spring 23 is applied when the thermal head 22 is moved upward. Since it has to be lifted with a torque that exceeds the pressure, it requires a large torque, which increases costs. It also requires a large space for vertical movement, and it also requires a deceleration device to generate large torque, which causes the speed to decrease. There were problems such as being slow and generating noise.

Therefore, an object of the present invention is to solve the problems of the conventional pressure welding device as described above, and to provide an inexpensive, quick, and noise-free device that does not require a special motor for engaging and disengaging the thermal head from the platen. The purpose of the present invention is to provide a pressure welding device that operates without any pressure.

Means for Solving the Problems In order to achieve the above object, the present invention displaces the thermal head between a platen engagement position and a platen detachment position by operating a cam fixed to the platen shaft. and a leaf spring that bends and presses the thermal head against the platen when the arm member is in the platen engagement position, and when the arm member is in the platen detachment position, the thermal head It is designed to separate from the platen by pressing .

In the thermal head pressure welding device as described above, when the platen rotates, the cam rotates in synchronization with the rotation of the platen, and as the cam rotates, the arm member moves to one platen engagement position or the other platen detachment position. When moving to the engagement position, the leaf spring is pressed and bent, and this bend presses the thermal head to press it against the platen, and when it moves to the disengagement position, a part of itself Press the thermal head to release it from the platen.

Embodiments The present invention will be described in detail with reference to FIGS. 1 to 3.

1 is a platen, 2 is a thermal head, and 3 is a cam fixed to the platen shaft.

The base end of the lower arm of an inverted Z-shaped arm member 5 is supported by a pivot 6 on the machine frame (not shown), a cam follower 7 that engages with the cam 3 is provided at the tip, and a platen is provided at the base end of the upper arm. A spring engaging member 8 extending in the same direction as the shaft is provided, and a head engaging member 9 extending in the same direction is provided at the tip.

An engaging piece 10 is provided vertically on the engaging member 9, and the arm member 5 is configured such that the cam follower 7 is always engaged with the cam 3 by a spring 11.

The thermal head 2 is attached to a head holding member 12 having support shafts 13 at both ends pivoted to side plates (not shown) at a position deviated to one side of the vertical center line of the platen 1.

A spring holding member 14 is provided on the opposite side of the support shaft 13 of the thermal head 2 with respect to the vertical centerline of the platen 1, and a support @ 15 of this holding member 14 is slidably fitted into a horizontal elongated hole 17 provided in a side plate 16. The leaf spring 18 whose tip is held by the holding member 14 has its middle part bent downwardly toward the thermal head 2, and its base end is supported by a base 19.

The operation of such a pressure welding device will be explained with reference to FIGS. 2 and 3.

FIG. 2 shows a state in which the thermal head 2 is engaged with the platen 1, 20 is a recording paper, and the hatched portion indicates a recording area.

In this case, the cam follower 7 engages with the top dead center of the cam 3,
As a result, the arm member 5 rotates counterclockwise around the pivot 6, the spring engaging member 8 presses the spring holding member 14 to the left, the leaf spring 18 curves downward, and the thermal head 2 Touch the top surface of and press down. This pressing causes the thermal head 2 to rotate counterclockwise about the support shaft 13 and engage with the platen 1 .

FIG. 3 shows a state in which the thermal head 2 is detached from the platen 1. In this case, the cam follower 7 engages with the bottom dead center of the cam 3, and as a result, the arm member 5 rotates clockwise about the pivot 6, and the spring engaging member 8 engages the spring holding member 14.
away from.

The curved portion of the leaf spring 18 is expanded and separated from the upper surface of the thermal head 2 . At the same time, the engagement piece 10 of the head engagement member 9 comes into contact with the upper surface of the thermal head 2 and presses it down. This pressing causes the thermal head 2 to rotate clockwise about the support shaft 13 and separate from the platen 1.

Effects of the Invention The present invention is as described above, and the arm member is moved to the platen engagement position by the operation of the cam fixed to the platen shaft.
Alternatively, move to the platen detachment position, press and bend the leaf spring in the engagement position to press the thermal head and press it against the platen, and in the detachment position press a part of the thermal head to release it from the platen. Since the thermal head is detachable, there is no need for a separate drive source such as a motor to engage and disengage the thermal head from the platen, and the thermal head can be synchronized with the rotation of the platen. The thermal head automatically engages and disengages according to the rotation of the platen, without the need for a sensor, etc., and there is no malfunction. It has the effect of not requiring space.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of an embodiment of the invention, and FIG. Third
The figure is an explanatory diagram of the main parts during engagement and disengagement of the same as above, and FIG. 4 is a drawing similar to FIG. 1 of a typical example of a conventional thermal head pressure welding device. 1...Platen 2...Thermal head 3...
・Cam 5...Arm member 6...Pivot 7...Cam follower 8...Spring engagement member 9
...Head engagement member 10...Engagement piece 12.
... Head holding member 13 ... Support shaft 15 ... Support shaft 19 ... Base 14 ... Spring holding member 18 ... Leaf spring horse Figure 1 and Figure 2 procedural amendment May 1989 Relationship with the person who amends the display of the 22nd incident

Claims (1)

[Claims] 1. In a thermal transfer recording device equipped with a platen and a thermal head that engages with and disengages from the platen, a cam fixed to the platen shaft moves the thermal head between the platen engagement position and the platen disengagement position. and a leaf spring that bends and presses the thermal head against the platen when the arm member is in the platen engagement position, and when the arm member is in the platen detachment position. A thermal head pressure welding device, characterized in that a part of the thermal head is pressed to separate the thermal head from a platen.