JPH04334457A - Optical fixing device of thermal printer - Google Patents

Abstract

PURPOSE:To prevent the leakage of light from a lamp house. CONSTITUTION:A thermal recording material 14 is thermally recorded by a thermal head 16 and optically fixed by an optical fixing device 20. The optical fixing device 20 is constituted of a box-shaped lamp house 21 and an ultraviolet lamp 22. A skirt 23 having flexibility is fixed to the lower part of the lamp house 21 so that the leakage of light is prevented and no trouble is imparted to the rotation of a platen drum 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fixing device for a thermal printer.

0002

[Prior Art] In thermosensitive recording, a thermosensitive recording material is used in which a thermosensitive coloring layer is layered on a support, and a thermal head is pressed against this thermosensitive coloring layer and heated to cause it to develop color. . The parts that are not heated by the thermal head have the ability to develop color, so they will develop color if heat is applied during storage. Therefore, a heat-sensitive recording material is known in which the coloring ability is lost by irradiating the material with electromagnetic radiation, such as ultraviolet rays, using an optical fixing device after heat recording.

[0003] Furthermore, a yellow thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a cyan thermosensitive coloring layer are sequentially provided on a support.
Color thermosensitive recording materials are also known that record color images with multiple thermal recordings (for example, Japanese Patent Application Laid-Open No. 61-213169).
. In this color thermosensitive recording material, after the first thermosensitive coloring layer provided on the surface side, for example, the yellow thermosensitive coloring layer, is thermally recorded, the second magenta thermosensitive coloring layer is thermally recorded. When the magenta thermosensitive coloring layer is thermally recorded, the yellow thermosensitive coloring layer is also heated, so that the unrecorded portion develops color. Therefore, the yellow thermosensitive coloring layer contains a diazonium salt compound that is photodecomposed by near ultraviolet light of approximately 420 nm, and the magenta thermosensitive coloring layer contains approximately 360 nm.
Contains a diazonium salt compound that is photodecomposed by 5 nm ultraviolet light.

0004

[Problem to be solved by the invention] In conventional thermal printers, an optical fixing device is placed right next to the thermal head.
The optical fixing device is operated while the thermal head is thermally recording the heat-sensitive recording material, and when the recorded portion reaches the optical fixing device, it is irradiated with ultraviolet rays. When thermal recording and optical fixing are performed simultaneously in this manner, ultraviolet rays leaking from the optical fixing device may enter the heat-sensitive recording material before thermal recording and cause optical fixation. This light leakage is particularly likely to occur when the diameter of the platen drum is reduced in order to downsize the thermal printer.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention includes a flexible skirt attached to the lower part of the lamp house so as to contact the outer periphery of the platen drum. Because this skirt has flexibility,
The clamp member for pressing the edge of the heat-sensitive recording material passes through without any problem. Furthermore, if the skirt is made of a material with good conductivity, it is effective in preventing the platen drum or the heat-sensitive recording material from being charged.

[0006]

[Embodiment] As shown in FIG. 3, the platen drum 10 is
The rotating shaft 11 is connected to the frame 1 through a pair of bearings 12.
3, and is rotated continuously or intermittently in the arrow direction by a pulse motor (not shown). A heat-sensitive recording material 14 is wound around the outer periphery of the platen drum 10, and its leading end is held down by a clamp member 15. A thermal head 16 is arranged at the print position. As is well known, the thermal head 16 has a large number of heating elements arranged in a line in the main scanning direction. Each heating element heats the heat-sensitive recording material 14 to develop color, and prints a dot pattern image on the heat-sensitive recording material 14.

On the downstream side close to the thermal head 16,
An optical fixing device 20 is arranged. As shown in detail in FIG. 4, the optical fixing device 20 includes a box-shaped lamp house 21,
The ultraviolet lamp 22 and skirt 23 housed inside this
It is composed of. This skirt 23 is fixed to the opening 21a of the lamp house 21, and its tip is in contact with the outer periphery of the platen drum 10. Further, the skirt 23 needs to be flexible so as not to obstruct passage of the clamp 15, and have light blocking properties so as not to transmit ultraviolet rays. Materials that meet these two properties include rubber, colored plastic film, etc., and shapes include sheets and brushes. A conductive rubber or static dissipating brush is particularly good because it can leak static electricity. In this example, FIG.
As shown in Figure 2, a static discharge brush is used.

During printing, the platen drum 10 rotates in the direction of the arrow to move the thermal recording material 14 to a printing position facing the thermal head 16. The thermal head 16 heats the thermosensitive recording material 14 by causing a plurality of heating elements arranged in the main scanning direction to generate heat. Simultaneously with this thermal recording by the thermal head 16, the ultraviolet lamp 22 is turned on. Since this ultraviolet lamp 22 is surrounded by a lamp house 21 with a skirt 23 attached, ultraviolet rays will not leak outside.

As the platen drum 10 rotates, the portion recorded by the thermal head 16 moves toward the optical fixing device 20. Then, the clamp 15 enters the lamp house 21 while curving the skirt 23. The portion of the heat-sensitive recording material 14 that has entered the lamp house 21 is irradiated with ultraviolet rays and optically fixed.

When the platen drum 10 rotates once, printing of the heat-sensitive recording material 14 is completed. After printing is completed, the clamp 15 is moved to remove the printed thermosensitive recording material 14 from the platen drum 10. In the case of color heat-sensitive recording materials, two types of ultraviolet lamps with different wavelengths of ultraviolet light are arranged in the lamp house 17, and are selectively turned on depending on the type of heat-sensitive coloring layer being printed. Further, a lamp house may be provided for each two ultraviolet lamps.

Although the above embodiment is a line printer in which the heat-sensitive recording material 14 and the thermal head 16 are moved relatively in one dimension, the present invention can also be applied to a serial printer in which the heat-sensitive recording material 14 and the thermal head 16 are moved relatively in two dimensions. can do.

0012

[Effects of the Invention] As explained in detail above, the present invention has the following features:
Because a flexible skirt is provided at the bottom of the lamp house,
Light from the optical fixing device does not leak into unrecorded areas.

[Brief explanation of drawings]

FIG. 1 is a side view of a thermal printer of the present invention.

FIG. 2 is a sectional view of the lamp house.

FIG. 3 is a plan view of the thermal printer.

FIG. 4 is a bottom view of the lamp house.

[Explanation of symbols]

10 Platen drum 14 Heat-sensitive recording material 16 Thermal head 20 Optical fixing device 21 Lamp house 22 Ultraviolet lamp 23 Skirt

Claims (1)

[Claims] 1. An optical fixing device for a thermal printer, characterized in that a flexible skirt is attached to the lower part of the lamp house so as to come into contact with the outer periphery of the platen drum.