JP2863049B2 - Light irradiation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light irradiation apparatus for selectively irradiating light to a recording medium having at least two color-forming layers which react with light to cause a reaction.

[0002]

2. Description of the Related Art As an image recording apparatus such as a printing printer or an image printer, there is a thermal printer of a type in which a thermal recording material is heated using a thermal head to form images such as characters and figures. When an image is formed using the above-described thermosensitive recording material, for example, a single color such as black is sufficient for some images, but a thermosensitive recording method capable of multicolor recording is desired in order to cope with demands such as diversification of expression. ing.

In response to such a demand, Japanese Patent Laid-Open No. 2-14 / 1990
Japanese Patent No. 1279 discloses a multicolor heat-sensitive recording material capable of forming a full-color image. This thermal recording material
It has three thermosensitive coloring layers that produce different colors, and can produce full color depending on the degree of coloring of each layer. Specifically, the thermosensitive recording material is provided with a first thermosensitive coloring layer, a second thermosensitive coloring layer, and a third thermosensitive coloring layer in this order from the surface side, and each layer is heated by a thermal head. . In the heat-sensitive recording material, the heat-sensitive coloring temperature is set lower in the surface layer, and at least the two layers from the top are fixed with dyes by ultraviolet rays after coloring. Therefore, the color density of the already-colored layer does not increase when the lower layer of the already-colored layer is heated by heating.

A recording method using the heat-sensitive recording material is as follows.
The first color forming layer is heated to a first temperature to form a color,
The coloring layer is irradiated with the first ultraviolet ray to stop coloring and fix the dye. Next, the second color forming layer is heated to a second temperature to form a color, and the second color is similarly irradiated with second ultraviolet rays to stop the color formation and fix the dye. Finally, the third coloring layer is heated to a third temperature to develop a color, thereby completing the recording. In the thermosensitive recording material, for example, if the first to third coloring layers contain coloring materials so as to develop yellow, magenta, and cyan in order, full-color can be obtained by heating the thermosensitive recording material as described above. An image can be formed.

To emit the first and second ultraviolet rays, a fluorescent lamp corresponding to each wavelength is used. The fluorescent lamp is formed by applying a fluorescent substance to the inner surface of a glass tube filled with mercury vapor, and further emits ultraviolet rays from a phosphor layer excited by ultraviolet rays emitted by arc discharge between electrodes at both ends. By appropriately selecting the fluorescent substance, an ultraviolet ray having a desired wavelength can be obtained.

In order to utilize the amount of light efficiently by unidirectionally directing the direction of emission of ultraviolet light, a reflector layer is provided between the glass tube and the fluorescent substance, and an opening ( Aperture). The opening may be coated with a phosphor as in the reflector layer, or may be transparent without the phosphor.

[0007] If the phosphor is also applied to the opening of the reflector layer, the ultraviolet rays converge on the opening, whereby the phosphor is further excited and the ultraviolet rays are emitted. Further, when the opening is transparent, all the ultraviolet light reflected by the reflector layer is emitted from the transparent opening, so that the emitted ultraviolet light can be used effectively.

[0008]

Although there are two types of fluorescent lamps having such a configuration, it has been found that even with the same configuration of the fluorescent lamp, the amount of light varies depending on the wavelength of ultraviolet light emitted. For example, in a fluorescent lamp having a structure in which a fluorescent substance is applied to an opening, it is found that, if the fluorescent substance changes, the wavelength of the emitted ultraviolet light also changes, but the emission efficiency also changes, and the amount of emitted light changes. Similarly, even with a fluorescent lamp having a transparent opening, it was found that, when the fluorescent material was changed, the emission efficiency was changed along with the wavelength of the ultraviolet light, and the amount of emitted light was changed.

Therefore, if two fluorescent lamps having the same configuration are used to obtain two types of ultraviolet light, the light intensity may be reduced due to a decrease in the emission efficiency of either of the fluorescent lamps. When fixing is performed with a fluorescent lamp having a low light amount, it takes a long time to obtain a predetermined light amount, and there is a problem that the fixing time becomes longer, and as a result, the printing time becomes longer.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and to provide a light irradiation apparatus having a structure capable of effectively utilizing the amount of light from a fluorescent lamp and shortening a reaction process time by the fluorescent lamp. It is in.

[0011]

The above object according to the present invention is achieved by the following constitutions. (1) The color development of a recording medium, which has at least two color-forming layers that are adjusted to have different wavelength sensitivities for photo-reaction and can select a color-reaction layer by changing the irradiation wavelength, is caused to react by light irradiation. 1. A light irradiation device comprising: a fluorescent lamp having a transparent opening as a short-wave light source; and a fluorescent lamp having a phosphor layer in the opening as a long-wave light source.

(2) The color development of a heat-sensitive recording material having at least two layers containing a diazo compound adjusted to have different wavelengths for fixing color development, wherein the fixing layer can be selected by changing the fixing light source, 1. A light irradiation fixing device for fixing by light irradiation, comprising a fluorescent lamp having a transparent opening as a short-wave light source and a fluorescent lamp having a phosphor layer in the opening as a long-wave light source.

[0013]

There is a recording medium on which an image is recorded by photopolymerization as a recording medium on which recording is performed by photoreaction. For example, an image of a plurality of colors is recorded by photopolymerizing a reactive substance by irradiation with light of a plurality of wavelengths. Then, there is a multicolor recording medium which is heated and developed, and the present invention is applicable to the multicolor recording medium.

Further, as another recording medium by photoreaction, a heat-sensitive recording material in which a plurality of main diazonium salts having different photosensitive wavelengths and a coupler which reacts with each diazonium salt when heated and develops a different color is combined. The heat-sensitive recording material destroys the diazo compound by light irradiation to fix the color density, and the present invention is applicable to the multicolor heat-sensitive recording material.

When irradiating at least two kinds of coloring layers with light, two kinds of wavelengths are selected for the light, and two kinds of fluorescent lamps are required to obtain light of each of these wavelengths. Among these, the short wavelength light source has a transparent opening, and the long wavelength light source has a phosphor applied to the opening. By selecting and using a fluorescent lamp whose opening is configured as described above according to the emission wavelength, the required light amount can be obtained even in a short time,
Printing time can be shortened. In particular, the present invention is effective when the wavelength difference between the two types of light is about 30 nm.

The multicolor recording medium irradiated with light according to the present invention employs a method of fixing the density by irradiating ultraviolet rays to a color-developed portion by heating, as disclosed in Japanese Patent Application Laid-Open No. 2-141279. There is a heat-sensitive recording material, and the present invention is suitable for image recording using the heat-sensitive recording material.

In the case of this heat-sensitive recording material, the wavelengths of the ultraviolet rays used are 370 nm and 420 nm. The threshold for selecting the wavelength is 400 nm, and a light source having a transparent opening is used as a light source for obtaining ultraviolet light having a peak at a wavelength of 370 nm shorter than 400 nm.
As a light source for obtaining ultraviolet light having a longer wavelength at 420 nm, an opening with a phosphor is used.

The following substances can be used as the fluorescent substance that emits ultraviolet light.

Here, suitable phosphors for emitting each wavelength are selected. For example, 370 nm
SrB ₄ O ₇ : Eu (peak wavelength: 368 nm) is used as a phosphor for obtaining ultraviolet rays, and Sr ₂ P ₂ O ₇ : Eu (peak wavelength: 421 nm) is used for a phosphor for obtaining ultraviolet rays of 420 nm.

In the case of a light source having a peak at a wavelength of 370 nm, the amount of light is larger when the light is transparent than when the phosphor is applied to the opening. Conversely, in the case of a light source having a peak at a wavelength of 420 nm, the amount of light is greater when the phosphor is applied to the opening than when the phosphor is transparent. The reason for this is not clear, but is presumed to be because the ultraviolet light transmittance of the phosphor itself that emits ultraviolet light of each wavelength is different.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited to only this embodiment. The present invention is a light irradiation fixing device. In order to facilitate understanding of the present invention, first, a heat-sensitive paper that can be used in the present invention and an image forming method using the heat-sensitive paper will be described. An embodiment will be described. The image forming method described below is a method for forming a full-color image using the heat-sensitive recording material described in JP-A-4-28585.

FIG. 1 is a sectional view of the thermal paper 2. Thermal paper 2
Has three thermosensitive coloring layers 6, 8, 10, intermediate layers 12, 14 and a surface protective layer 17 on a support 4. The first coloring layer 6 develops yellow by heating, and the second coloring layer 8
Develops magenta, the third coloring layer 10 develops cyan, and the first coloring layer 6 to the third coloring layer 10
By heating three times in order, full color can be developed. Each of the coloring layers 6, 8, and 10 has a different thermal sensitivity.
The coloring layer 6 develops a color at a low temperature (about 100 ° C.), and the second coloring layer 8
Develops color at a medium temperature (about 110 ° C.), and the third color forming layer 10 develops a color at a high temperature (about 130 ° C.). The dye concentration of the first color forming layer 6 and the second color forming layer 8 is fixed by irradiating ultraviolet rays immediately after the color is formed, and the color is not formed by the subsequent heating.

FIG. 2 is a schematic structural view of a printing portion of the image forming apparatus. A thermal head 20 is provided so as to face a rubber platen 18 that supports the thermal paper 2. The thermal head 20 may include a linear heating element group extending in the width direction of the thermal paper 2, and may be a line head that relatively scans the thermal paper 2 by moving the thermal paper 2, and may be a direction perpendicular to the longitudinal direction of the platen 18 ( A serial thermal head including a linear heating element group extending in the direction of thermal recording material conveyance and moving along the width direction of the thermal paper 2 may be used. In that case, the platen shape is desirably a flat shape instead of a cylindrical shape.

Further, adjacent to the platen 18, the thermal paper 2
The light irradiation fixing device 22 for fixing the color development is provided. The fixing device 22 includes fluorescent lamps 24a and 24b, and the ultraviolet rays from the fluorescent lamps 24a and 24b reach the thermal paper 2 and decompose the diazo compound in the color-forming layer to fix the density.

Thermal head 20 and fluorescent lamp 24
A transport roller pair 26 for transporting the thermal paper 2 is disposed on both sides of the rollers a and b. The transport roller pair 26 can rotate forward and reverse, and can transport the thermal paper 2 in either the left or right direction. The thermal paper 2 is heated by the thermal head 20 while being conveyed on the platen 18, and develops color, and is irradiated with ultraviolet rays by the fluorescent lamps 24a and 24b to fix the color.

The thermal paper 2 can perform full color recording and black recording. First, the full color recording mode will be described. The thermal paper 2 is heated by the thermal head 20 while being supported by the platen 18, and can produce full color. The thermal head 20 can heat the thermal paper 2 at three kinds of temperatures, about 100 ° C. (low temperature), about 110 ° C. (medium temperature), and about 130 ° C. (high temperature) by controlling the amount of electricity. 20 scans the same portion of the thermal paper 2 three times to perform a full-color recording process.

That is, the first color forming layer 6 is heated at a low temperature in the first scan of the thermal head 20, the second color forming layer 8 is heated at a medium temperature in the second scan, and the third color forming layer 10 is heated to a high temperature in the third scan. Heat with. The temperature of each heating element group of the thermal head 20 is adjusted by the width of the energizing pulse.

The fluorescent lamps 24a and 24b arranged adjacent to the thermal head 20 have wavelengths of 42
The thermal paper 2 can be irradiated with ultraviolet rays of 0 nm and 370 nm, and the first fluorescent layer 24 a
Irradiation with ultraviolet light of 20 nm is performed, and irradiation of ultraviolet light of 370 nm on the second coloring layer 8 by the second fluorescent lamp 24b fixes the coloring of these layers 6 and 8. The developer in each of the layers 6 and 8 is decomposed by the irradiation of ultraviolet rays and loses its coloring function, so that the coloring does not proceed even by subsequent heating. The unused thermal paper 2 has a yellow color, but the yellow color disappears due to the irradiation of ultraviolet rays.

When the image forming process is started, the sheet-shaped thermal paper 2 or the thermal paper 2 cut into a sheet from a roll is placed between the platen 18 and the thermal head 20 from left to right in the figure. Supplied to. The supplied thermal paper 2 is reciprocated while being nipped by the two transport roller pairs 26, and at this time, the thermal head 20, the fluorescent lamps 24a, 24
By operating b, the recording process on the thermal paper 2 is performed. The supplied thermal paper 2 is transferred to the thermal head 2 in the process to the right.
0, and the ultraviolet rays are radiated by both fluorescent lamps 24a and 24b.

Following the movement of the thermal paper 2, the thermal paper 2 is first heated at a low temperature by the thermal head 20, and the first coloring layer 6 develops yellow. First colored layer 6 after yellow coloring
Then, ultraviolet rays are irradiated by the first fluorescent lamp 24a to fix the density.

When the yellow color fixing process is completed, the thermal paper 2 is reversed and driven backward, and is heated again by the thermal head 20 at an intermediate temperature during the subsequent forward movement, so that the second color forming layer 8 develops magenta. After the magenta coloring, the second coloring layer 8 is irradiated with ultraviolet rays by the second fluorescent lamp 24b to fix the density. When the magenta coloring is completed, the thermal paper 2 is again driven to reverse and move backward, and is heated at a high temperature by the thermal head 20 at the time of the subsequent forward movement.
Cyan develops in the coloring layer 10. The third color forming layer 10
Since is not further heated thereafter, it is not necessary to irradiate ultraviolet rays to fix the density. Thus, each layer 6,
A full-color image is formed by synthesizing the color-formed images at 8 and 10.

Next, the black recording mode will be described. If each color of yellow, magenta, and cyan is developed at the same portion, the color becomes black. Therefore, if the same portion of each of the layers 6, 8, and 10 is heated so that the highest density is obtained, black can be recorded. Each of the layers 6, 8, and 10 may be heated at a different temperature. However, by heating the thermal paper 2 at a high temperature for coloring the cyan layer, the respective layers 6, 8, and 10 simultaneously develop the respective colors. be able to.

High-temperature thermal paper 2 for developing cyan
Is heated, the first color forming layer 6 and the second color forming layer 8 are similarly heated to a high temperature in the process of conducting heat to the third color forming layer 10. The first coloring layer 6 and the second coloring layer 8 are the third coloring layer 10.
Since the thermal sensitivity is lower, the first color forming layer 6 and the second
The color forming layer 8 also develops yellow and magenta, respectively. Therefore, it is possible to record in black by simply heating the thermal paper 2 by the thermal head 20 once at a high temperature for cyan coloring. The above-described full-color recording mode and black recording mode can be appropriately switched according to the recording content.

Next, the configuration of a light irradiation fixing device according to an embodiment of the present invention will be described. FIG. 3A is a partially cutaway perspective view of one end of the first fluorescent lamp 24a that emits long-wave ultraviolet light (wavelength 420 nm), and FIG. 3B is a cross-sectional view.

The fluorescent lamp 24a includes a transparent glass tube 30.
Are provided at both ends with a base 34 having a pin 32, and a voltage is applied to the pin 32. The glass tube 30 is configured to be airtight, and has mercury vapor sealed therein. On the inner surface of the glass tube 30, there is provided a reflective layer 38 having an opening 36 which is partially cut out in the circumferential direction in the longitudinal direction, and a fluorescent layer 40 is provided on the inner surface of the reflective layer 38.

The phosphor layer 40 is made of a phosphor for emitting ultraviolet rays having a wavelength of 420 nm, which is applied to the first color forming layer 6 for forming magenta. The fluorescent substance is Sr ₂
P ₂ O ₇ : Eu (peak wavelength 421 nm) can be used. The opening 36 of the reflective layer 38 is a portion that substantially serves as an ultraviolet emission port, and the fluorescent lamp 24 a is provided so that the opening 36 faces the thermal paper 2.

FIG. 4A shows a short-wave ultraviolet ray (wavelength 370n).
FIG. 4B is a partially cutaway perspective view of one end of the second fluorescent lamp 24b that emits m), and FIG. 4B is a cross-sectional view. The configuration of the fluorescent lamp 24b is different from that of the fluorescent lamp 24a in that the fluorescent layer 40 is made of a fluorescent substance for emitting ultraviolet light having a wavelength of 370 nm and that the opening 36 is not coated with a fluorescent substance. Yes, the other configurations are the same. In this fluorescent lamp 24b, SrB ₄ O ₇ : Eu (peak wavelength 368 nm) can be used as a fluorescent substance.

By emitting two kinds of ultraviolet rays by the two kinds of fluorescent lamps 24a and 24b, the first color forming layer 6 which emits yellow and the second color forming layer 8 which emits magenta have wavelengths of 420 nm and 370 nm, respectively. Irradiation of ultraviolet rays to fix the color development. The ultraviolet light having a wavelength of 420 nm applied to the first color forming layer 6 is, as shown in FIG.
It was found that the amount of light increased when the fluorescent material was also applied to the openings 36 that emit ultraviolet light.

Conversely, the wavelength 3 to be applied to the second color forming layer 8
As shown in FIG. 4, the amount of the 70 nm ultraviolet light is such that the fluorescent material is not applied to the opening 36 and the ultraviolet light emitted from the internal phosphor layer 40 from the transparent portion of the glass tube 30 is emitted from the opening. Was found to increase.

The opening 36 as in the first fluorescent lamp 24a
Although a fluorescent material is also coated on the opening 36 and a fluorescent material is not coated on the opening portion 36, such as the second fluorescent lamp 24b, each of which is known. It has not yet been known that a specific amount of ultraviolet light having the specific wavelength can be obtained using the lamps 24a and 24b. However, according to experiments performed by the present inventors, the amount of ultraviolet light having a wavelength of 420 nm is larger when the fluorescent material is applied to the opening 36, and the wavelength 3
It was found that the amount of light of the 70 nm ultraviolet ray was larger in the transparent opening 36. As a result, the fixing time for each wavelength can be reduced.

The fixing times according to the combination of the opening configuration of the fluorescent lamp and the ultraviolet light emitted by the fluorescent lamp are shown below. As the thermal paper, use is made of the one described in JP-A-4-28585.
As described above, yellow color was fixed with ultraviolet light having a wavelength of 420 nm, and magenta color was fixed with ultraviolet light having a wavelength of 370 nm. The results are shown in Table 1 below.

[0042]

[Table 1]

As can be seen from the above results, when a fluorescent lamp with a transparent opening is used as the light source for both wavelengths as in Comparative Example 1, the yellow fixing time is 30 seconds and the magenta fixing time is 35 seconds. The yellow fixing time was shorter than the magenta fixing time, but the total fixing time of yellow and magenta was 65 seconds. Further, when a fluorescent lamp having a phosphor layer in an opening portion was used as a light source for both wavelengths as in Comparative Example 2, the yellow fixing time was 25 seconds, and Comparative Example 1 was used.
Although shorter, the magenta fixing time was significantly increased to 40 seconds, and as a result, the total fixing time of yellow and magenta was unchanged at 65 seconds.

On the other hand, a fluorescent lamp having a phosphor layer in an opening is used as a light source for ultraviolet light having a wavelength of 420 nm.
When a fluorescent lamp having a transparent opening is used as a light source for ultraviolet light having a wavelength of 370 nm, the total fixing time of yellow and magenta is reduced by 5 seconds as compared with the conventional example, and the fixing time is reduced by 1 compared with the conventional example.
It has been reduced by 0%. Therefore, a combination of using a fluorescent lamp with an opening with a phosphor as a light source for ultraviolet light having a wavelength of 420 nm and a fluorescent lamp with a transparent opening as a light source for ultraviolet light having a wavelength of 370 nm may be effective in shortening the fixing time. all right.

[0045]

According to the present invention, a fluorescent lamp having a transparent opening is selected as a short-wavelength light source, and a fluorescent lamp having a phosphor layer in an opening is selected and provided as a long-wavelength light source. Since the recording medium can be effectively irradiated with light, the irradiation time can be reduced for each coloring layer, and the overall photoreaction time of the recording medium can be reduced. In particular, the present invention is effective for recording on a multicolor heat-sensitive recording material by a method of fixing a color density by decomposing diazo compounds in different color-forming layers by short-wave ultraviolet light and long-wave ultraviolet light.

[Brief description of the drawings]

FIG. 1 is a sectional view of a thermal paper.

FIG. 2 is a schematic configuration diagram of a printing portion of the image forming apparatus.

FIG. 3A is a perspective view of a fluorescent lamp for a long-wave light source,
(B) is a sectional view.

FIG. 4A is a perspective view of a fluorescent lamp for a short-wave light source,
(B) is a sectional view.

[Explanation of symbols]

 2 Thermal paper 4 Support 6 First color forming layer 8 Second color forming layer 10 Third color forming layer 18 Platen 20 Thermal head 22 Light irradiation fixing device 24a, 24b Fluorescent lamp 26 Transport roller pair 30 Glass tube 36 Opening 38 Reflecting layer 40 Phosphor layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/32 B41M 5/28-5/34 H01J 61/30-61/40

Claims (2)

(57) [Claims] 1. A method of producing a recording medium, comprising: a layer having at least two color-forming layers adjusted to have different wavelength sensitivities for photo-reaction, and selecting a color-forming layer to be responsive by changing the irradiation wavelength; A light irradiation device for reacting, comprising: a fluorescent lamp having a transparent opening as a short-wave light source; and a fluorescent lamp having a phosphor layer in the opening as a long-wave light source. 2. The color development of a heat-sensitive recording material having at least two color development layers containing a diazo compound adjusted to have different wavelength sensitivities for fixing color development and selecting a color development layer to be fixed by changing the irradiation wavelength. A light irradiation fixing device, wherein a fluorescent lamp having a transparent opening is provided as a short-wave light source, and a fluorescent lamp having a phosphor layer in the opening is provided as a long-wave light source. .