JPH04201373A - Thermal head pressing mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head pressing mechanism in a thermal transfer recording device.

[Conventional technology]

The conventional thermal head pressing mechanism is disclosed in Japanese Patent Application Laid-Open No. 62-169.
A thermal head holding mechanism as described in Japanese Patent No. 664 is provided. This thermal head holding mechanism consists of a thermal head in which a plurality of heating resistors are arranged in a row, and two sets of holding members placed on both sides of the thermal head. It is installed. A conventional thermal head pressing mechanism is shown in FIG. The thermal head pressing mechanism includes a head holding portion 1° which is a holding member and an arm 2 which is a pressing member. Left spring 3. It consists of a right spring 4° and a center axis 5, and the head holding part 1 has an L chassis 6,
R chassis 7, rotating chassis 8. It consists of a 9° pin and a thermal head 10. The L chassis 6 and the rotary chassis 8 are fixed to the left and right ends of the thermal head 10, and the rotary chassis 8 is rotatably coupled to the R chassis 7 by a pin 9. That is, the thermal head 10 is rotatable about the pin 9 with respect to the R shear 7 . This degree of rotational freedom occurs in the head holding portion 1 due to mechanical errors such as variations in mounting accuracy. This is provided to correct the deviation in the contact position between the heating resistor 10a and the drum 11, and to eliminate uneven contact between the heating resistor 10a. Furthermore, the L chassis 6 and the R chassis 7 have a structure that allows them to rotate around a central axis 5, and the central axis 5 is fixed to a side plate (not shown). The arm 2 is also rotatable about the central axis 5 like the L chassis 6 and the R chassis 7, and a drive shaft 14 is fixed at the left end of the arm 2.

Further, the left side of the arm 2 and the L chassis 6 and the right side of the arm 2 and the R chassis 7 are connected by a left spring 3 and a right spring 4. The drum 11 is rotatably attached to a side plate (not shown), and is rotationally driven by a power source and power transmission means (not shown). The operation of pressing the thermal head 1o against the drum 11 is achieved by forcibly displacing the tip of the drive shaft 14 in the direction of arrow a in the figure using a cam (not shown) to move the arm 2 around the central axis 5. Rotate and pull the left spring 3 and right spring 4. The spring force (tensile force) generated in these left spring 3 and right spring 4 is the head holding part 1.
is pressed down to press the thermal head 10 against the drum 11. In other words, the pressing force of this thermal head pressing mechanism is
This is caused by the tensile force of the left spring 3 and right spring 4.

[Problem to be solved by the invention]

In the prior art, there is a problem in that unevenness in the pressing force in the width direction of the thermal head and the drum causes density unevenness in the width direction of the recorded image, deteriorating the image quality.

[Means to solve the problem]

In order to achieve the above object, the present invention has the position of the force applied to the arm to press the thermal head against the drum to the rear of the arm, and furthermore, by making it possible to change the position in the width direction, the width of the thermal head and the drum can be changed. The pressing force in the direction was made uniform.

[Effect]

The above method utilizes torsional deformation of the arm, and by changing the position of the force applied to the arm in the width direction,
To adjust the tensile force of the left and right springs so that the pressing force of the thermal head is uniform, without changing the amount of torsional deformation of the left and right arms around the force point and using springs with different spring constants for the left and right springs. I can do it. As a result, density unevenness in the width direction of the recorded image can be reduced, and a high-quality image can be obtained.

〔Example〕

An embodiment of the present invention will be described below.

First, a first embodiment of the present invention will be described using FIGS. 1 and 2. 1 and 2, the recording paper 12 and the ink sheet 13 are omitted. FIG. 1 shows a thermal head pressing mechanism that is a part of a thermal transfer recording apparatus. Arm 2 which is a pressing member. Left spring 3. Right spring 4. Central axis5.
The head holding part 1 consists of a lever 15, a rotating shaft 16, an L chassis 6, an R chassis 7, a rotating chassis 8° pin 9. It is composed of a thermal head 10.

The L chassis 6 and the rotating chassis 8 are the thermal head 10.
The rotary chassis 8 is rotatably connected to the R chassis 7 by a pin 9. That is, the thermal head 10 has a degree of freedom of rotation around the pin 9 with respect to the R chassis 7. This rotational degree of freedom is
The head holder 1 is mounted to correct a deviation in the contact position between the heat generating resistor 10a and the drum 11 caused by mechanical errors such as variations in accuracy, and to eliminate uneven contact of the heat generating resistor 10a. In addition, L chassis 6 and R chassis 7
has a structure that can rotate around a central axis 5, and the central axis 5 is fixed to a side plate (not shown). The arm 2 is also rotatable about the central axis 5 like the L chassis 6 and the R chassis 7.

Further, the left side of the arm 2 and the L chassis 6 and the right side of the arm 2 and the R chassis 7 are connected by a left spring 3 and a right spring 4. The lever 15 is attached to be slidable in the axial direction of a rotating shaft 16, and the rotating shaft 16 is rotatably fixed to a side plate (not shown) and rotationally driven by a power source and power transmission means (not shown). The drum 11 is
It is rotatably attached to a side plate (not shown) and rotationally driven by a power source and power transmission means (not shown).

The recording operation in this thermal head pressing mechanism involves wrapping the recording paper 12 around the drum 11, pressing the thermal head 10 against the drum 11 via the ink sheet 13, and pressing the thermal head 10 against the drum 11.
1 of the thermal head 10 while rotating the heating resistor 1 of the thermal head 10.
The ink is applied to the ink sheet 13 and transferred to the recording paper 12 by generating heat from the ink. The ink sheet 13 has three or four colors (yellow: Y color, magenta = M
color.

This is a sheet on which ink of 20 colors of cyan or 928 colors of bran is sequentially applied. Note that the recording operation is set to Y color 2.
For M color and 0 color, the drum 11 is rotated three times and the three colors are superimposed and transferred onto the recording paper 12, thereby obtaining a color recorded image. In addition, the thermal head 10 is connected to the drum 1.
The operation of pressing the thermal head 1 in Fig. 2(a)
By rotating the rotating shaft 16 from a state where the arm 2 and the drum 11 are separated from each other, the arm 2 is forcibly displaced and rotated around the central axis 5, and the left spring 3 and the right spring 4 are pulled. The spring force (tensile force) generated in these left spring 3 and right spring 4 pushes down the head holding part 1 and presses the thermal head 10 against the drum 11. FIG. 2(b) shows a state in which the thermal head 10 and drum 11 are pressed together. That is, the pressing force of this thermal head pressing mechanism is generated by the tensile force of the left spring 3 and the right spring 4.

The reason why the lever 15 is slidably attached in the axial direction of the rotating shaft 16 is that by changing the position of the lever 15, the position of the point of force applied to the arm 2 can be changed, and the point of force applied to the arm 2 can be moved inside the arm 2. This is to equalize the pressing force of the thermal head 10 by changing the amount of torsional deformation on the left and right sides of the thermal head 10 and changing the tensile force of the left spring 3 and the right spring 4 without using springs with different spring constants for the left and right springs 4. . In this way, the present thermal head pressing mechanism can adjust the amount of torsional deformation of the arm 2, and by locating the lever 15 at the center of the rotating shaft 16, the amount of torsional deformation on the left and right sides of the arm 2 can be made equal. is also possible. By adjusting the amount of torsional deformation of the arm 2 on the left and right sides, the amount of deformation of the left spring 3 and the right spring 4 changes, and the tensile forces of the left spring 3 and the right spring 4 can be adjusted. In addition, considering the characteristic that the pressing force is greater on the side where the rotatable member of the head holder 1 is located, by locating the lever 15 on the left side of the center of the rotating shaft 16, this characteristic can be corrected and the thermal head The pressing force of 10 can be adjusted to be uniform in the width direction. By doing this, a high-quality image without density unevenness is obtained.
7 Next, a second embodiment of the present invention will be described with reference to FIG. Figure 3 is the L in Figure 4.
The part of the chassis 6 on which the left wing 3 is hung (the part inside the circle) has been modified. This is a mechanism that adjusts the height of the hook 17 by rotating the screw 18. By adjusting the height of the hook 17, the amount of deformation of the left spring 3 when the thermal head 10 is pressed against the drum 11 can be adjusted, and the tensile force of the left spring 3 changes.

By changing the tensile force of the left spring 3, it is possible to make the pressing force of the thermal head 10 and the drum 11 uniform in the width direction without using springs with different spring constants for the left and right springs, thereby reducing uneven density. Get high quality images.

〔Effect of the invention〕

According to the present invention, since the pressing force of the thermal head and the drum can be made uniform in the width direction, density unevenness in the width direction of a recorded image can be reduced, and a high-quality image can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a thermal head pressing mechanism according to an embodiment of the present invention, and FIG. 2 is a side view of FIG. 1. FIG. 3 is a partially enlarged view of a second embodiment of the present invention, and FIG. 4 is a perspective view of a conventional embodiment. DESCRIPTION OF SYMBOLS 1... Head holding part, 2... Arm, 3... Left spring, 4... Right spring, 5... Center shaft, 6... L chassis, 7... R chassis, 8 ...Rotating chassis, 9
...Pin, 10...Thermal head, 10a...
Heat generating resistor, 11...Drum, 12...Recording paper, 1
3... Ink sheet, 14 yen - 1st I Kaya Zfi3 (^" Cb) Kaya 4th

Claims (1)

[Claims] 1. A mechanism for pressing a thermal head in which a recording paper and an ink sheet are stacked on a drum and heating resistors are arranged in a row, and two sets are arranged on both sides to support the thermal head. At least one set of holding members includes a member that is rotatable relative to the thermal head near the heating resistor of the thermal head, and a member that presses the thermal head against the drum via two sets of holding members. In a thermal head pressing mechanism of a thermal transfer recording device, which is composed of a pressing member for holding the pressing member and a spring connecting the holding member and the pressing member, the position of the point of force applied to the pressing member can be changed in the width direction. Features a thermal head pressing mechanism.