JPH03207666A - Thermal line head pressing device - Google Patents

Abstract

PURPOSE:To prevent a recorded image from irregularities in density and a local blur by a method wherein pressing springs for pressing the center part and end parts of a thermal line head against a platen roller through thermal recording paper are provided with adjusting mechanisms for adjusting the spring forces thereof. CONSTITUTION:When a thermal line head 1 is projected to a platen roller 3 at the center part thereof, adjusting screws 5a, 5c for pressing the both ends of the head are tightly fastened to set pressing springs 4a, 4c small in height (h), and an adjusting screw 5b for pressing the center part is lightly fastened to set a pressing spring 4b relatively large in height (h). In this manner, a pressing force is set large at the both ends and small at the center part. When a thermal line head 1 is recessed to the platen roller 3 at the center part thereof, a relatively large height (h) is set by the adjusting screws 5a, 5c, and a relatively small height (h) is set by the adjusting screw 5b. In this manner, a pressing force is set small at the both ends and large at the center part.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a thermal line head pressing device.

BACKGROUND OF THE INVENTION In recent years, with the progress of the information society, there has been remarkable development of printing and recording devices. Among them, thermal line heads have become extremely popular as output recording devices for information communication terminal equipment such as facsimiles because of their ease of use and ease of maintenance.

．． A conventional thermal line head pressing device will be described below.

FIG. 2 is a perspective view of a conventional thermal line head pressing device. 1 is a thermal line head, 2 is a thermal recording paper, 3 is a platen roller, and 4-a, 4-c press both ends of the thermal line head 1. The pressure spring 4-b is a pressure spring that presses the center portion of the thermal line head 1.

The operation of the thermal line head pressing device constructed as described above will be explained below.

The thermal line head 1 has pressing springs 4-a, 4-b, 4
The button is pressed by the platen roller 3 made of silicone rubber through the heat-sensitive recording paper 2. In this state, the heating element of the thermal line head 1 is energized to generate heat, and the amount of heat generated is The thermally reactive material of the thermosensitive recording paper 2 is reacted to develop color to perform print recording, and after recording, the platen roller 3 rotates 3 pages to display the image as it is sent to the thermosensitive recording paper 2. .

Problems to be Solved by the Invention However, in the conventional structure, if the warpage due to the manufacturing of the thermal line head exceeds a certain amount, the pressure distribution state on the platen due to pressing becomes uneven in the longitudinal direction of the thermal line head. However, there is a problem in that uneven density and local blurring of the recorded image occur when the button is pressed in areas where the pressure is low.

An object of the present invention is to solve such problems and provide a thermal line head pressing device with good print quality.

Means for Solving the Problems In order to solve the above problems, the present invention provides an adjustment mechanism that adjusts the spring force of a pressure spring that presses the center and both ends of a thermal line head against a platen roller via thermal recording paper. It was constructed as follows.

Function: The present invention has the above-mentioned structure, and addresses the manufacturing difficulties of thermal line heads, and adjusts the distribution of pressing force between the buttons at both ends and the center, thereby improving the non-uniformity of the pressure state on the platen. This is what I did.

Embodiment FIG. 1 is a sectional view of a thermal line head pressing device according to an embodiment of the present invention. 1 is a thermal line head, 2 is a thermal recording paper, 3 is a platen roller, 4-a,
4-b and 4-c are pressure springs that press the buttons at both ends and the center of the thermal line head 1, as in the conventional example, and 5-a.
, 5-b, and 5-c are screws for adjusting the pressing force, and correspond to the pressing springs 4-a, 4-b, and 4-c, respectively. 8-a, 6-b, 6-c are receivers for pressing springs 4-a, 4-b, 4-c, and 7 is a fixed side member with taps for adjustment screws 5-a, 5-b, 5-c. is cut out. h is the pressure spring 4-a, 4-b, 4
-c height, pressing force adjustment screws 5-a, es-b, s
Control with -c. And pressing spring 4-a~4-01
Adjustment screws 5-a to 5-c and saucer 6-
A to 6-a are provided on the side opposite to the platen roller 3 button of the thermal line head 1 and the thermal recording paper 2, and have 6 pages.

The operation of the thermal line head pressing device constructed as described above will be explained below.

In the manufacturing process of the thermal line head 1, for a head whose center is convex toward the platen roller 3 side, an adjusting screw 5- is used to press both ends of the thermal line head 1.
Tighten the pressure springs 4-a and 5-c strongly, set the height h of the pressure springs 4-a and 4-(+ to be small, and weakly tighten the adjustment screw 5-b that presses the center part. -b height h is set to a large value.This causes the pressure at both ends to be strong and the pressure at the center to be weak. For this case, use adjustment screws 5-ai and 5-c to set h to a larger value, and use adjustment screw 5-b to set h to a smaller value. This will be the setting.

In the past, the pressure at the center and both ends of the thermal line head was constant, so the ability to absorb the dimensional accuracy of the thermal line head and platen by 6 was low, but with the present invention, these dimensional variations can be reduced. It will be possible to absorb significantly more than conventional methods.

Effects of the Invention The present invention has a mechanism that can adjust the pressing force of the thermal line head, so that the pressing force can be set to any desired value.
Since the pressing force can be optimally set according to the manufacturing process of the thermal head, uneven pressure distribution on the platen can be significantly improved compared to conventional methods, and image quality deterioration such as density unevenness and local blurring of recorded images can be avoided. This is an excellent thermal line head pressing device that does not cause any problems.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a thermal line head pressing device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a conventional thermal line head pressing device. 1... Thermal line head, 2...
Thermal recording paper, 3...Platen roller, '4-
JL, a-b, 4-c---... Pressing spring, 5-a, 5-b, 5-c-... Screw for adjusting pressing force.

Claims (1)

[Claims] A thermal line head, a platen roller that presses the thermal line head through a thermal recording paper, and a platen roller that presses at least both ends and a central portion of the thermal line head on a side opposite to the platen roller and the thermal recording paper. 1. A thermal line head pressing device comprising: a pressing spring whose spring force can be adjusted individually.