JPH06155777A - Thermal printer - Google Patents

Abstract

PURPOSE:To reduce the title device in size and to improve the efficiency of fixing colors. CONSTITUTION:Ultraviolet lamps 10, 11 are disposed to face a thermal recording medium 3 from the opposite side of a thermal head 6. After an yellow image is thermally recorded by the thermal head 6, the thermal recording medium 3 is irradiated with an ultraviolet ray emitted from the ultraviolet lamp 10 for fixing an yellow image through a transparent guide plate. This ultraviolet ray is emitted on an yellow thermal coloring layer through a transparent support body of the thermal recording medium 3. Ultraviolet ray that passed through the thermal recording medium 3 is reflected by a reflection plate 12 of a guide plate 8 and is emitted again on the thermal recording medium 3. A magenta thermal coloring layer is optically fixed in the same manner as the aforementioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer, and more particularly to a thermal printer used for thermal recording of a thermal recording material for an overhead projector having a transparent support.

[0002]

2. Description of the Related Art In a thermal recording type thermal printer,
A heat-sensitive recording material in which a heat-sensitive color-forming layer is layered on a support is used, and a thermal head is pressed against this heat-sensitive color-developing layer to heat the color-forming layer for color recording. The part that is not heated by the thermal head has the ability to develop color, so if heat is applied during storage, it will develop color. Therefore, after the thermal recording of the thermosensitive recording material, the coloring ability is lost by irradiating the ultraviolet rays from the ultraviolet lamp.

Such thermal recording and optical fixing are carried out while the thermal recording material is moved relative to the thermal head and the ultraviolet lamp, and the thermal printer mainly uses the platen drum system and the reciprocating system by this moving system. Can be divided into The former is one in which the heat-sensitive recording material is wound around a platen drum of a size corresponding to the size of the heat-sensitive recording material and rotated, and the thermal head and the ultraviolet lamp are arranged around the platen drum. In the latter, the thermosensitive recording material is nipped by a conveying roller to reciprocate in a substantially horizontal direction, and the thermal head and the ultraviolet lamp are arranged on one side of the recording material passage.

The former method requires a platen drum having a large diameter for winding the thermal recording material.
It is difficult to downsize the device. On the other hand, in the latter method, a platen roller having a small diameter can be used, which is advantageous for downsizing.

Further, the heat-sensitive recording material is generally used with a paper as a support, and is used for an overhead projector (hereinafter abbreviated as OHP) using a transparent support such as polyethylene terephthalate (PET). There is.

[0006]

The thermosensitive coloring layer of the thermosensitive recording material is provided on one side of the support. Therefore, in the above-described reciprocating thermal printer, both the thermal head and the ultraviolet lamp are arranged on the same side of the recording material passage, which makes it difficult to downsize the apparatus. That is, since a mechanism such as a motor for moving the thermal head up and down, a cooling fan, etc. are arranged near the thermal head, it is not possible to secure the installation space for the ultraviolet lamp as it is, and for example, the height of the case of the thermal printer. The UV lamp is arranged to be high.

Further, when the heat-sensitive recording material for OHP is irradiated with ultraviolet rays for optical fixing, the ultraviolet rays pass through the support and escape to the opposite side. Therefore, as compared with a general heat-sensitive recording material in which the support is paper, the amount of effective ultraviolet rays hitting the heat-sensitive color-developing layer is small, so that there is a problem that fixing efficiency is lowered and fixing time is long.

The present invention makes it possible to downsize the device and
It is an object of the present invention to provide a thermal printer for OHP having a short fixing time.

[0009]

According to a first aspect of the present invention, there is provided a thermal printer in which a UV lamp is mounted on a thermal head so that UV rays emitted from the UV lamp pass through a transparent support to optically fix the thermosensitive coloring layer. I placed it on the other side,
The degree of freedom in design is increased, and the device can be easily downsized.

A thermal printer according to a second aspect of the present invention is provided with a table for transporting the heat-sensitive recording material and a reflecting plate mounted on the table for reflecting the ultraviolet rays transmitted through the support so as to return them to the heat-sensitive coloring layer. The efficiency of optical fixing is remarkably improved and the fixing time is shortened.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a thermal printer 1 is configured such that a sheet-shaped heat-sensitive recording material 3 is reciprocally conveyed by a pair of nip rollers 2, and recording and fixing are carried out in the meantime. The thermosensitive recording material 3 is for OHP having a transparent support. To the right of the nip roller pair 2 are provided a platen roller 5 for supporting the thermosensitive recording material 3 at the recording position, and a thermal head 6 for thermally recording an image on the thermosensitive recording material 3 supported thereon.

As is well known, the thermal head 6 has a large number of heating elements arranged in a line in the main scanning direction.
Each heating element generates thermal energy according to the density of the pixel to thermally record an image on the thermal recording material 3. The platen roller 5 and the nip roller pair 2 are rotated at the same peripheral speed by a pulse motor (not shown).

A recording material passage 9 formed by guide plates 7 and 8 is provided on the left side of the nip roller pair 2, and ultraviolet rays for emitting ultraviolet rays for optically fixing the heat-sensitive recording material 3 are provided on the platen roller 5 side thereof. Lamps 10 and 11 are arranged. As a result, the ultraviolet lamps 10 and 11
Is arranged in a portion that has not been used conventionally, a wide space is secured on the thermal head side, and a circuit board or the like can be arranged with a margin in this space.

The guide plate 7 is made of a transparent plastic which transmits ultraviolet rays, and a reflecting plate 12 made of aluminum, for example, which reflects ultraviolet rays is joined to the inside of the guide plate 8 on the opposite side.

The ultraviolet lamp 10 has an emission peak of about 42.
The 0 nm rod-shaped yellow fixing lamp is used, and the ultraviolet lamp 11 is used for magenta fixing light emission peak of about 365 nm. The reflection films 10a and 11 are provided on 3/4 of these peripheral surfaces.
A is applied, and ultraviolet rays are applied to the thermosensitive recording material 3 from a quarter area facing the platen roller 5 side.

A paper feed / eject port 9a is provided at the end of the recording material passage 9, and a paper feed / eject roller pair 14 is provided here. From here, for example, when the thermal recording materials 3 are manually inserted one by one, the thermal recording materials 3 are nipped by the pair of paper feeding and discharging rollers 14 and carried into the recording material passage 9. Also,
A tray (not shown) for accumulating the recorded thermal recording material 3 discharged from the paper supply / discharge port 9a is provided outside the paper supply / discharge port 9a.
Is provided.

In FIG. 2, the thermosensitive recording material 3 comprises a cyan thermosensitive coloring layer 16, a magenta thermosensitive coloring layer 17, a yellow thermosensitive coloring layer 18, and a protective layer 19 on a transparent support 15 made of, for example, a PET sheet. It is a layered structure.
The thermosensitive coloring layers 16 to 19 are layered from the surface in the order of thermal recording. The cyan thermosensitive coloring layer 16 contains an electron-donating dye precursor and an electron-accepting compound as main components,
Cyan develops color when heated.

As the magenta thermosensitive coloring layer 17, a diazonium salt compound having a maximum absorption wavelength of about 365 nm,
It contains a coupler which thermally reacts with this to develop a magenta color. The magenta thermosensitive coloring layer 17 loses its coloring ability due to photolysis of the diazonium salt compound when ultraviolet rays in the vicinity of 365 nm are irradiated after the magenta image is thermally recorded by the thermal head 6.

The yellow thermosensitive coloring layer 18 contains a diazonium salt compound having a maximum absorption wavelength of about 420 nm, and a coupler which thermally reacts with this compound to develop yellow. When this yellow thermosensitive coloring layer 18 is irradiated with near-ultraviolet rays in the vicinity of 420 nm, the yellow thermosensitive coloring layer 18 is optically fixed and loses its coloring ability.
Note that the light is also fixed by near-ultraviolet rays of 365 nm, which has a higher energy than this. Further, the thermosensitive recording paper 3 is light yellow due to the diazonium salt compound, but when the thermosensitive coloring layers 16 and 17 are sufficiently photo-fixed, the unrecorded portion of the thermosensitive recording paper 3 is light yellow to transparent. Changes to.

Next, the operation of the above embodiment will be described. When the thermosensitive recording material 3 is inserted between the paper feeding / discharging roller pair 14 with the support 15 facing downward, the thermosensitive recording material 3 is carried into the recording material passage 9 from the paper feeding / discharging port 9a, and the ultraviolet lamp 10, After passing through 11, the sheet is conveyed toward the recording position. During this conveyance, the platen roller 5 is rotated clockwise and the thermal head 6 is retracted from the recording position. The thermosensitive recording material 3 is temporarily stopped when the tip 3a reaches the position of the nip roller pair 2. At this time, the tip of the printing portion of the thermal recording material 3 is set at the recording position where the thermal head 6 faces.

Subsequently, the nip roller pair 2 and the platen roller 5 are reversely rotated, and the thermosensitive recording material 3 starts to be conveyed to the left in the drawing. At the same time, thermal recording by the thermal head 6 is started and the ultraviolet lamp 10 for yellow fixing is turned on. Each heating element of the thermal head 6 is heated to a temperature in consideration of the color development characteristics of the yellow thermosensitive coloring layer 18, and a yellow image is thermally recorded on the thermosensitive recording material 3 line by line.

When the printing portion reaches above the ultraviolet lamp 10, as shown in FIG. 1, the ultraviolet lamp 10 irradiates near ultraviolet light having a wavelength of about 420 nm through the guide plate 7. This ultraviolet light passes through the support 15, the cyan thermosensitive coloring layer 16, and the magenta thermosensitive coloring layer 17 to optically fix the yellow thermosensitive coloring layer 18. The ultraviolet rays pass through the yellow thermosensitive coloring layer 18 and once exit from the thermosensitive recording material 3, but are reflected by the reflection plate 12 to irradiate the thermosensitive recording material 3 again. As described above, since the ultraviolet rays are effectively used, the yellow heat-sensitive coloring layer 18 is optically fixed in a short time.

The thermal recording material 3 is heat-recorded by the thermal head 6 up to the rear end of the printing portion, and then further conveyed, and all the heat-printed printing portions are irradiated with ultraviolet rays from the ultraviolet lamp 10. When the rear end portion 3b of the thermosensitive recording material 3 reaches the nip position of the nip roller pair 2, the rotation direction of the nip roller pair 2 is switched, and the thermosensitive recording material 3 is conveyed toward the recording position again.

After the tip 3a of the thermosensitive recording material 3 reaches the position of the nip roller pair 2 again, the rotational directions of the nip roller pair 2 and the platen roller 5 are switched, and the thermal recording of the magenta image is started by the thermal head 6. .
At the same time, the ultraviolet lamp 10 is turned off, and the ultraviolet lamp 11 for magenta fixing is turned on instead. When the printing portion on which the magenta image is thermally recorded reaches above the ultraviolet lamp 11, the ultraviolet lamp 11 causes almost 36
Ultraviolet rays in the vicinity of 5 nm are transmitted through the support 15 and irradiated,
The magenta thermosensitive coloring layer 17 is optically fixed. At this time, some of the ultraviolet rays pass through the heat-sensitive recording material 3, but the reflector 1
Since the light is reflected by 2 and re-enters the magenta thermosensitive coloring layer 17, the optical fixing is performed in a short time.

After the thermal recording of the magenta image is completed, the thermosensitive recording material 3 is further conveyed, and when the magenta thermosensitive coloring layer 17 in the entire printing portion is optically fixed, the nip roller pair 2
Is rotated in the reverse direction, and again toward the recording position, the thermal recording material 3
Will be returned. When the leading end of the printing portion reaches the recording position, the rotational directions of the nip roller pair 2 and the platen roller 5 are switched, and the thermal head 6 thermally records a cyan image on the thermal recording material 3. And the thermal recording material 3
Are conveyed toward the paper feed / eject port 9a. Also at this time,
The ultraviolet lamp 11 is turned on, and the rear end portion 3b of the heat-sensitive recording material 3 which has not been exposed to the ultraviolet light is also exposed to the ultraviolet light to be bleached. In this way, the thermal recording material 3 for which all thermal recording and optical fixing have been completed is discharged to the outer tray via the paper supply / discharge port 9a.

The thermal printer 21 shown in FIG. 3 uses an ultraviolet-transparent table 22 on which the thermal recording material 3 is placed and which is horizontally moved. With this table 22 in between,
The thermal head 6 and the ultraviolet lamps 10 and 11 are arranged vertically, and the table 22 is sandwiched between the ultraviolet lamps 10 and 11.
A reflection plate 24 having an ultraviolet reflection surface 23 is arranged at a position facing 11 of the above.

The table 22 is made of a material that transmits ultraviolet rays.
For example, it is formed of a transparent acrylic plate or the like, and a clamp member 25 for pressing and fixing the tip end portion 3a of the thermosensitive coloring layer 3 to the table 22 is provided at the upper end portion thereof.
A rack gear 26 is attached to the lower edge of the table 22 in the moving direction, and a pulse motor 27 is attached to the rack gear 26.
The pinion gear 28, which is rotationally driven by, is meshed.

This thermal printer 21 has a table 2
2 holds the thermosensitive recording material 3 and reciprocates twice and a half times, and during this, each thermosensitive coloring layer thermally records and optically fixes. Also in the case of this optical fixing, the ultraviolet rays are radiated from the back surface of the support 15 and the ultraviolet rays which have passed through the thermal recording material 3 are reflected by the ultraviolet reflecting surface 2.
The heat-sensitive recording material 3 is irradiated again by means of 3.

The thermal printer 31 shown in FIG. 4 is constructed by joining a reciprocating table 33 with an ultraviolet reflecting plate 32 made of, for example, aluminum. The thermal head 6 and the ultraviolet lamps 10 and 11 are arranged on the same side, and the thermal recording material 3 is set on the table 33 so that the support 15 faces the reflection plate 32. The ultraviolet rays emitted from the ultraviolet lamps 10 and 11 at the time of optical fixing are directly irradiated on the heat-sensitive layer and, after passing through the transparent support of the heat-sensitive recording material 3, are reflected by the ultraviolet reflecting plate 32 to be reflected on the heat-sensitive recording material. Since the process returns to 3, the effective ultraviolet rays are increased and the optical fixing is quickly performed.

In the embodiment described above, the two ultraviolet lamps are arranged adjacent to each other, but they may be arranged separately on the left and right sides of the recording position. In this case, 1 thermal recording material
While reciprocating, for example, it is possible to perform thermal recording and optical fixing of the yellow image and the magenta image, respectively,
The thermal recording material can be printed in one and a half round trips, and the printing time is shortened. Also, an example in which an aluminum plate is used as the reflection plate has been described, but white paint or aluminum vapor-deposited plastic may be used as long as it has a high reflection efficiency of ultraviolet rays. Further, the line printer for performing relative movement and recording of the thermal head or the thermal recording material in the sub-scanning direction has been described, but the present invention can also be applied to a serial printer for relative movement in two dimensions for recording.

[0031]

As described in detail above, according to the thermal printer of the present invention, the ultraviolet lamp emitted from the ultraviolet lamp transmits the transparent support to optically fix the thermosensitive coloring layer. Is arranged on the opposite side of the thermal head, the degree of freedom in design is increased and the apparatus can be downsized. In addition, since the table that conveys the heat-sensitive recording material is provided with a reflection plate that reflects the ultraviolet rays that have passed through the support so as to return it to the heat-sensitive coloring layer, the UV rays emitted from the ultraviolet lamp can be effectively used as the heat-sensitive recording material. Since it is irradiated, the optical fixing of the thermosensitive recording material can be performed quickly,
Fixing time can be shortened.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a thermal printer in which an ultraviolet lamp is arranged on the side opposite to a thermal head.

FIG. 2 is an explanatory diagram showing a layer structure of a thermosensitive recording material.

FIG. 3 is an explanatory diagram showing a thermal printer using an ultraviolet-transparent table.

FIG. 4 is an explanatory diagram showing a thermal printer in which a reflection plate that reflects ultraviolet rays is provided on the upper surface of a table.

[Explanation of symbols]

 1, 21, 31 Thermal printer 3 Thermal recording material 6 Thermal head 7, 8 Guide plate 10, 11 Ultraviolet lamp 12, 24, 32 Reflector 15 Support 22, 33 Table

Claims (2)

[Claims] 1. A thermal printer in which a thermosensitive recording material having a thermosensitive coloring layer layered on a transparent support is thermally recorded by a thermal head, and then ultraviolet rays are radiated from the ultraviolet lamp to perform optical fixing. On the opposite side of the thermal head,
The thermal printer is characterized in that the ultraviolet rays emitted from the ultraviolet lamp are transmitted through a transparent support to optically fix the thermosensitive coloring layer. 2. A thermal printer in which a thermosensitive recording material having a thermosensitive coloring layer layered on a transparent support is thermally recorded by a thermal head, and then ultraviolet rays are radiated from an ultraviolet lamp to the image to thereby perform optical fixing. A thermal printer comprising: a table for transporting materials; and a reflection plate mounted on the table for reflecting the ultraviolet rays transmitted through the support so as to return the ultraviolet rays to the thermosensitive coloring layer.