JP2899482B2 - Thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer for thermally recording a video image or the like on a thermosensitive recording material.

[0002]

2. Description of the Related Art Thermal printers are classified into thermal printers and thermal transfer printers. Among them, thermal printers tend to be widely used because they can thermally record an image directly on a thermal recording material. Most of them incorporate a monochrome thermal printer. Recently, for example, as described in JP-A-61-213169, a magenta thermosensitive coloring layer is provided on a support.
A color thermosensitive recording material has also been proposed in which a cyan thermosensitive coloring layer and a yellow thermosensitive coloring layer are sequentially provided so that a full-color image can be directly thermally recorded.

Such a thermosensitive recording material is thermally recorded by a thermal head while being conveyed while being wound around a platen drum, and is then applied to a specific thermosensitive coloring layer from a fixing light source provided near the platen drum. Ultraviolet rays in a suitable wavelength range are irradiated and fixed. As a fixing light source, a cylindrical ultraviolet lamp is generally used.
An ultraviolet reflective film is provided except for the area facing the platen drum. This ultraviolet reflection film prevents unnecessary diffusion of ultraviolet light and increases the amount of ultraviolet light emitted to the platen drum side.

[0004]

However, in the above-described ultraviolet lamp, the reflecting film cannot completely reflect the ultraviolet light, and there is an ultraviolet light which passes through the reflecting film. For example, when the reflection area by the ultraviolet reflection film is set to 270 degrees and the transmission area is set to 90 degrees, it is found that there is a loss of about 20%. For this reason, in order to perform fixing sufficiently, an ultraviolet lamp having a large light emission amount is used or the fixing time is lengthened. However, when an ultraviolet lamp having a large light emission amount is used, there is a problem that the device becomes large and expensive. On the other hand, if the fixing time is lengthened, there is a problem that the printing speed is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermal printer capable of sufficiently fixing a heat-sensitive recording material without prolonging a printing time or increasing the size and cost of an apparatus. .

[0006]

SUMMARY OF THE INVENTION A thermal printer according to the present invention allows a heat-sensitive recording material to be conveyed around the outer periphery of an ultraviolet lamp. And the rest is a reflection area. UV lamp
Since the transmissive area can be wider than the reflective area, the loss of ultraviolet rays is reduced.

[0007]

1, a thermosensitive recording material 10 is fed by a pair of conveying rollers 11 toward a recording position. At the recording position, a thermal head 12 and a rubber roller 13 are provided facing each other, and ultraviolet lamps 16 and 17 are disposed downstream thereof via a transport roller 14 and a switching guide plate 15. The thermal head 12 has a large number of heating elements arranged in a line in the main scanning direction, and each heating element generates heat energy according to the density of a pixel.

The ultraviolet lamp 16 has an emission peak of approximately 42
A 0 nm rod-shaped yellow fixing member is used for fixing, and the ultraviolet lamp 17 is used for magenta fixing having an emission peak of approximately 365 nm. Behind these UV lamps 16, 17,
A guide case 18 is provided, and ultraviolet lamps 16 and 17 are provided.
Arc-shaped passage 1 between the outer peripheral surface of the
9, 20 are formed. The switching guide plate 15 includes:
The transport direction of the heat-sensitive recording material 10 is selectively switched according to the heat-sensitive coloring layer on which the heat-sensitive recording material 10 is to be fixed, and the heat-sensitive recording material 10 is guided to the passage 19 or the passage 20.

Phosphors 21 and 22 are applied to the inner peripheral surfaces of the ultraviolet lamps 16 and 17, and an ultraviolet reflecting film 23 is provided in, for example, approximately a quarter of the region excluding the regions facing the passages 19 and 20. I have. In this way, the region from which ultraviolet rays are emitted is set to approximately ３ of the entire peripheral surface, and this region is
9 and 20, the loss of the amount of ultraviolet light applied to the heat-sensitive recording material 10 is reduced to about 1/3 (6 to 7%) of the related art. Therefore, the heat-sensitive recording material 10
While passing through 9, 20, it is quickly fixed by receiving sufficient ultraviolet rays.

On the outlet 25 side of the passages 19 and 20, a pair of transport rollers 26 and 27 are provided, and a switching guide plate 28 for changing the transport direction is rotatably provided downstream thereof. The switching guide plate 28 is rotated between a return position for returning the thermosensitive recording material 10 to the recording position again and a discharge position for discharging the thermosensitive recording material 10 on which recording and fixing have been completed. That is, the switching guide plate 28 is at the return position shown in FIG. 1 from the start of printing to the start of recording of a cyan image, and thereafter is turned to the discharge position 28a shown by a dotted line in FIG.

FIG. 3 shows an example of a heat-sensitive recording material. On the support 31, a cyan thermosensitive coloring layer 32, a magenta thermosensitive coloring layer 33, a yellow thermosensitive coloring layer 34, and a protective layer 35 are sequentially provided. Each of these thermosensitive coloring layers 32
34 are arranged from the surface in the order of thermal recording. For example, in the case of thermal recording in the order of magenta, yellow, and cyan, the positions of the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer are switched. .

As the support 31, an opaque coated paper or a plastic film is used. When an OHP sheet is formed, a transparent plastic film is used. The cyan thermosensitive coloring layer 32 contains an electron-donating dye precursor and an electron-accepting compound as main components, and develops cyan when heated. Magenta thermosensitive coloring layer 3
No. 3 contains a diazonium salt compound having a maximum absorption wavelength of about 365 nm and a coupler which reacts with the diazonium salt compound and develops magenta. When the magenta thermosensitive coloring layer 33 is irradiated with ultraviolet rays near 365 nm after the magenta image is thermally recorded by the thermal head 12, the diazonium salt compound undergoes photolysis and loses its coloring ability.

The yellow thermosensitive coloring layer 34 contains a diazonium salt compound having a maximum absorption wavelength of about 420 nm, and a coupler which thermally reacts with the diazonium salt to develop a yellow color. The yellow thermosensitive coloring layer 34 is also light-fixed when irradiated with near ultraviolet rays near 420 nm, and loses its coloring ability.
For this reason, light is fixed even by near-ultraviolet rays of 365 nm having higher energy. Since the magenta thermosensitive coloring layer 33 and the yellow thermosensitive coloring layer 34 contain a diazonium salt compound, the thermosensitive recording material 10 originally has a light yellow color. These thermosensitive coloring layers 33, 34
Is light-fixed, the unrecorded portion of the thermal recording material 10 changes from pale yellow to yellow to colorless.

The operation of the printer thus configured will be described. As shown in FIG. 1, the transport roller pair 11 nips the thermal recording material 10 and transports it toward a recording position.
When the leading end of the recording area of the thermal recording material 10 reaches the thermal head 12, the thermal head 12 thermally records a yellow image line by line. In the thermal recording of the yellow image, each heating element of the thermal head 12 generates heat at a temperature in consideration of the coloring characteristics of the yellow thermosensitive coloring layer 34. When the leading end of the thermosensitive recording material 10 reaches the switching guide plate 15, the ultraviolet lamp 16 is turned on and the thermosensitive recording material 10 is guided to the passage 19. The heat-sensitive recording material 10 is irradiated with near-ultraviolet light of about 420 nm by the ultraviolet lamp 16 while being conveyed in the passage 19, and is light-fixed so that yellow does not develop at the time of the next thermal recording of the magenta thermosensitive coloring layer 33. .

The heat-sensitive recording material 10 on which the yellow heat-sensitive coloring layer 34 is fixed is mounted on the switching guide plate 28 at the return position.
Is again guided to the recording position, and the magenta image is thermally recorded on the magenta thermosensitive coloring layer 33 line by line. During the thermal recording of the magenta image, the ultraviolet lamp 16 for yellow is turned off and the ultraviolet lamp 17 for magenta is turned on instead. Then, as shown in FIG. 2, the switching guide plate 15 is rotated, and the thermosensitive recording material 10 is guided to the passage 20. Here, ultraviolet light having a wavelength of about 365 nm is applied to the heat-sensitive recording material 10, and the magenta heat-sensitive coloring layer 33 is optically fixed.

The thermal recording material 10 is guided to the third recording position by the switching guide plate 28, and the thermal head 1
2, the cyan image is thermally recorded line by line. This cyan thermosensitive coloring layer 32 does not develop color in a normal storage state because the heat energy required for thermosensitive coloring is approximately 80 mJ / mm ² or more. The thermosensitive recording material 10 on which the cyan image has been recorded is guided to the passage 20 by the switching guide plate 15, and is further irradiated with ultraviolet rays while passing therethrough. Thus, the unrecorded portion, for example, the white frame or the white portion of the background is bleached without becoming yellowish and becomes colorless. During this time, the guide 28 is moved to the discharge position 28a.
And the heat-sensitive recording material 10 on which all recording and fixing are completed is discharged.

In the embodiment described above, the bleaching is performed by turning on the ultraviolet lamp 17 after the recording of the cyan image. However, this may be omitted. Further, the ultraviolet reflection film is disposed on the surface of the phosphor, but may be provided, for example, between the glass tube and the phosphor or on the outer surface of the glass tube.

Although the above embodiment is directed to a line printer for printing by moving a thermal head or a thermosensitive recording material relatively in the sub-scanning direction, the present invention is also applicable to a serial printer for printing by moving two-dimensionally relative to each other. can do. This serial printer uses a thermal head in which heating elements are arranged in the main scanning direction, moves in the sub-scanning direction during thermal recording, and the thermosensitive recording material moves in the main scanning direction.

[0019]

As described in detail above, according to the thermal printer of the present invention, the heat-sensitive recording material is turned around the ultraviolet lamp, and the ultraviolet lamp has a region where the heat-sensitive recording material turns around as an ultraviolet transmission region. Since the other area is used as the reflection area, the ultraviolet light generated from the ultraviolet lamp is effectively irradiated to the heat-sensitive recording material without waste,
The heat-sensitive recording material can be sufficiently fixed without extending the printing time or increasing the size and cost of the apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic view of a thermal printer showing a state in which a yellow thermosensitive coloring layer is optically fixed.

FIG. 2 is a schematic view of a thermal printer showing a state in which a magenta thermosensitive coloring layer is optically fixed.

FIG. 3 is an explanatory diagram showing a layer structure of a thermosensitive recording material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Thermal recording material 12 Thermal head 15, 28 Switching guide plate 16, 17 Ultraviolet lamp 19, 20 Passage 23 Ultraviolet reflective film

Claims (1)

(57) [Claims] 1. A thermal printer comprising a cylindrical ultraviolet lamp, which thermally records a heat-sensitive coloring layer of a heat-sensitive recording material and then irradiates with ultraviolet rays from the ultraviolet lamp to fix the heat-sensitive recording material. The ultraviolet lamp is a thermal printer in which the area around which the heat-sensitive recording material turns is an ultraviolet transmission area and the rest is a reflection area.