JPH06127013A - Thermal recorder - Google Patents

Abstract

PURPOSE:To compensate variation in sensitivity depending on environmental conditions to stabilize the image density in a thermal recorder. CONSTITUTION:A control part 42 modulates the output of a laser beam M from a preheating laser 14 through an acoustic optical modulator 26. The laser beam M heats a non-image part of a thermal recording material S to a color forming temperature or higher to form a black border 44. A desitometer 36 detects the density of the black border 44. The control part 42 controls the output of the preheating laser 14 through the acoustooptical modulator 26, thereby adjusting the black border 44 to a predetermined density. By adjusting the output of the preheating laser 14, the thermal recording material S is more precisely preheated to a temperature just below the color forming temperature by the preheating laser beam M outputted from the preheating laser 14. Furthermore, the thermal recording material S is heated to the predetermined color forming temperature by a semiconductor laser 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a preheating means for preheating a heat-sensitive recording material to heat an image portion of the heat-sensitive recording material to a color development temperature or lower and an outer portion of the image to a color development temperature or higher, The present invention relates to a thermal recording apparatus which detects the color density of the heated thermosensitive recording material by a densitometer and controls the output of the preheating means and / or the heating means so that the density becomes a predetermined density.

[0002]

2. Description of the Related Art Thermal recording apparatuses for imparting thermal energy to a thermal recording material to record an image or the like have been widely used. In particular, a laser has emerged which enables high-speed recording by using a laser as a heat source (Japanese Patent Laid-Open No. 50-23617).
JP-A-58-94494, JP-A-62-77983
No. JP-A-62-78964).

The present applicant has applied a color developing agent, a color developing agent and a light absorbing dye on a support as a heat sensitive recording material which is applied to such a thermal recording apparatus and is capable of recording a good image with high quality. The present invention has developed a material that develops a color at a density according to the applied heat energy, and has also developed an apparatus for recording on this heat-sensitive recording material using a laser beam, and has filed a patent application (Japanese Patent Application No. Hei 3). -62684, Japanese Patent Application No. 3-187
494).

In this heat-sensitive recording material, a support contains at least a basic dye precursor, and heat-melting microcapsules, a color developer and a light absorbing dye are dissolved in an organic solvent which is hardly soluble or insoluble in water. After that, it has a heat-sensitive layer formed by applying a coating liquid containing an emulsion that has been emulsified and dispersed.

The basic dye precursor has a property of developing a color by donating an electron or accepting a proton such as an acid, and is usually almost colorless, and lactone, lactam, sultone, spiropyran, ester, A compound having a partial skeleton such as amide, which is opened or cleaved by contact with a color developer, is used. Specifically, there are crystal violet lactone, benzoyl leuco methylene blue, malachite green lactone, rhodamine B lactam, 1,3,3-trimethyl-6′-ethyl-8′-butoxyindolinobenzospiropyran and the like.

[0006] As a developer for these color formers,
An acidic substance such as a phenol compound, an organic acid or a metal salt thereof, and an oxybenzoic acid ester is used. The developer preferably has a melting point of 50 ° C. to 250 ° C., and particularly preferably a water-insoluble phenol or organic acid having a melting point of 60 ° C. to 200 ° C. Specific examples of these color developers are described in, for example, JP-A-61-291183.

The light-absorbing dye is preferably a dye which absorbs little light in the visible light region and has particularly high absorption in the infrared region. The dyes include cyanine dyes, phthalocyanine dyes, pyrylium / thiopyrylium dyes, azurenium dyes, squarylium dyes, N
Metal complex salt dyes such as i and Cr, naphthoquinone dyes / anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium dyes, diimmonium dyes, and nitroso compounds be able to. Among these, it is preferable to use one having a high absorption rate of light in the near-infrared region having a wavelength of 700 nm to 900 nm from the viewpoint that a semiconductor laser that oscillates near-infrared light is put into practical use.

By the way, the thermosensitive recording material is set so as not to develop color at a predetermined temperature or lower in order to maintain a stable storage state. Therefore, the applicant of the present invention has a preheating means for preheating the heat-sensitive recording material to a predetermined temperature lower than the coloring temperature and a heating beam for heating the heat-sensitive recording material to the predetermined coloring temperature for the purpose of improving sensitivity during image recording. A thermal recording device provided with a generating means is proposed (Japanese Patent Application No. 4-41).
730).

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in connection with the above proposal, and accurately grasps the preheating temperature of the heat-sensitive recording material and adjusts the output of the preheating means and / or the heating means. By doing so, it is an object of the present invention to provide a thermal recording device capable of obtaining an image having a stable density.

[0010]

In order to achieve the above-mentioned object, the present invention comprises a color developing agent, a color developing agent and a light absorbing dye on a support, and develops a color at a concentration according to applied heat energy. Preheating means for preheating the image portion of the heat-sensitive recording material to a predetermined temperature lower than the coloring temperature and heating the outer portion of the image around the image portion to the coloring temperature or higher, and at least the image portion of the heat-sensitive recording material according to the image. Heating means for supplying the heat energy to heat the heat-sensitive recording material to a predetermined color development temperature, and a densitometer for detecting the density of the external portion of the image of the heat-sensitive recording material heated to the color development temperature or more by the preheating means, Temperature control means for controlling the output of the preheating means and / or the heating means so that the concentration detected by the densitometer becomes a predetermined concentration.

[0011]

In the above-described thermal recording apparatus according to the present invention, the preheating means uniformly heats the outer portion of the image around the image portion to the coloring temperature or higher. The temperature control means detects the density of the outside portion of the image via a densitometer and controls the output of the preheating means and / or the heating means to adjust the density of the outside portion of the image to a predetermined density. By adjusting the output of the preheating means and / or the heating means, the heat-sensitive recording material is preheated more accurately to the temperature immediately before the color development, and the heat-sensitive recording material is heated to the predetermined color development temperature by the heating means.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A thermal recording apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates a thermal recording apparatus. The thermal recording apparatus 10 mainly moves a thermal recording material S, which is sub-scanned and conveyed in the direction of arrow B, by laser beams L and M in the direction of arrow A. The image is recorded by scanning. In this case, as the heat-sensitive recording material S, a material that has a color former, a developer and a light absorbing dye on a support and develops color at a density according to the heat energy applied, for example, the above-mentioned Japanese Patent Application No. 3- It is suitable to use those described in Japanese Patent Application No. 62684, Japanese Patent Application No. 3-187494 and the like.

The thermal recording apparatus 10 includes a semiconductor laser 12 for outputting a recording laser beam L for heating the thermal recording material S to a color development temperature or higher, and an image recording portion of the thermal recording material S whose temperature is less than the color development temperature. A preheating laser 14 that outputs a preheating laser beam M that heats a portion other than an image to a coloring temperature having a predetermined density while heating the portion to a predetermined temperature. That is, the thermal recording device 10 includes a semiconductor laser 12 that functions as a heating unit, a collimator lens 16 that makes the laser beam L a parallel light beam, a cylindrical lens 18, a polygon mirror 20 that deflects the laser beam L, and an fθ lens. 22, a cylindrical mirror 24, a preheating laser 14 that functions as a preheating unit, an acousto-optic modulator (AOM) 26 that modulates the intensity of the preheating laser beam M output from the preheating laser 14, and The preheating laser beam M output from the acousto-optic modulator 26 is arranged in close proximity to the heat-sensitive recording material S and the reflecting mirrors 32 and 34 for guiding the preheating laser beam M to the polygon mirror 20 via the collimator lens 28 and the cylindrical lens 30. Preheated laser 14
A densitometer 36 for detecting the density of the color-developed portion of the heat-sensitive recording material S heated by the laser beam M for preheating outputted from. The outputs of the semiconductor laser 12 and the preheating laser 14 are drivers 38 and 40, respectively.
It is controlled by the control unit 42 via. The laser beam M for preheating is set to scan the upstream side of the thermal recording material S in the sub-scanning direction with respect to the laser beam L for recording.

The thermal recording apparatus 10 of this embodiment is basically constructed as described above, and its operation will be described below.

First, the control unit 42 passes through the driver 40.
Drive the preheating laser 14 and
Modulating the laser beam M for heat by the acousto-optic modulator 26
To do. This modulated laser beam M for preheating is heat-sensitive.
Predetermined heat energy is applied to the recording material S. here
And the heat-sensitive recording material S by the laser beam M for preheating
2A shows the relationship between the scanning position and the laser output.
The acousto-optic modulator 26 is sensitive to the laser beam M for preheating.
Scanning position T of image portion of recording material S₁~ T₂, T₃~ T
_FourWhen scanning between the two, the thermal recording material S is projected with the laser output b.
Preheat to keep the temperature below the specified color development temperature.
The laser beam M is modulated. In addition, the acousto-optic modulator 26
Indicates that the laser beam M for preheating is less than the image of the thermal recording material S.
Scanning of the outer part (hereinafter referred to as black border) 44
Position T₀~ T₁, T₂~ T₃, T _Four~ T_FiveScan between
At this time, heat-sensitive recording material S is heated with laser output a (a> b)
Laser light for preheating so that the temperature exceeds the specified color development temperature.
Modulate the frame M.

As described above, the acousto-optic modulator 26 outputs the output from the preheating laser 14 to the laser beam M having the laser output b required to preheat the heat-sensitive recording material S or the black border 44. A laser output a higher than the laser output b by a certain level for recording.
Of the laser beam M. The acousto-optic modulator 26
The preheating laser beam M modulated by is introduced into the polygon mirror 20 through the collimator lens 28, the cylindrical lens 30, and the reflection mirrors 32 and 34.

The laser beam M for preheating deflected by the polygon mirror 20 is applied to the thermosensitive recording material S via the fθ lens 22 and the cylindrical mirror 24 to preheat the image portion and to surround the surrounding black. The part of the border 44 is heated and a color is developed to a predetermined density. The black border 44 prevents light leakage from the periphery of the thermal recording material S by blackening and edging the periphery of the recorded image portion, and the contrast makes the recorded image clear and easy to see. It is for doing. Here, the densitometer 36 arranged close to the thermal recording material S detects the density. The detection signal of the densitometer 36 is input to the control unit 42, and the control unit 42 acousto-optically modulates the black border 44 to a predetermined blackening density (for example, 0.5) based on the detection signal. The output of the preheating laser 14 is modulated via the device 26. In this case, if the difference between the laser output a and the laser output b of the preheating laser 14 is kept constant, the black border 44 is adjusted so as to have a predetermined blackening density, whereby the image recording portion of the thermal recording material S is adjusted. Is preheated to the exact density just before color development.

On the other hand, the control unit 42 drives the semiconductor laser 12 via the driver 38. The semiconductor laser 12 is
The recording laser beam L modulated according to the gradation of the image recorded on the thermal recording material S is output (see FIG. 2B). The outputs I between the scanning positions T _{1 and} T _{2 and} between T _{3 and} T ₄ form a gradation image, and the scanning positions T ₀ to T 4
The output c between T ₁ , T _{2 to} T ₃ , T _{4 to} T ₅ forms a black border 44. The laser beam L thus modulated is introduced into the polygon mirror 20 via the collimator lens 16 and the cylindrical lens 18.

The recording laser beam L directly modulated and output from the semiconductor laser 12 is reflected by the reflecting surface of the polygon mirror 20 rotating at a high speed, and passes through the fθ lens 22 and the cylindrical mirror 24 to obtain a thermosensitive recording material. The thermal recording material S guided in S and conveyed in the sub-scan direction in the arrow B direction is subjected to main scanning in the A direction. And
A desired image is recorded on the thermal recording material S.

Here, the scanning positions T _{0 to} T ₁ , T ₂ to
Between T ₃ and T _{4 to} T ₅ , as shown in FIG. 2C, the output a + c of the laser output a of the laser beam M for preheating and the output c of the laser beam L for recording is added. The black border 46 is formed by the laser beam. In this case, the semiconductor laser 12 does not need to have a sufficient output to form the black border 46. Therefore,
The black border 46 can be formed by the semiconductor laser 12 and the preheating laser 14 which have a relatively low output.

Between the scanning positions T _{1 to} T ₂ and T _{3 to} T ₄ , the output I of the recording laser beam L and the laser output b of the preheating laser beam M are added to obtain the density of I + b. An image is formed with a laser output of In this case, since the thermosensitive recording material S has been preheated accurately to the temperature immediately before the color development by the laser beam M, an image of a predetermined density is formed by the output I.

As described above, the image recorded on the thermal recording material S is, as shown in FIG. 1, a black border 4 consisting of an outer frame in which an image colored in a desired gradation is blackened.
It will be the one surrounded by 4. In this case, the density of the black border 44 formed by the laser beam M for preheating is detected in advance, and the output of the preheating laser 14 is controlled via the acousto-optic modulator 26.
By setting to a predetermined density, it is possible to accurately heat the environmental temperature and the heat-sensitive recording material S to a temperature immediately before color development. As a result, it is possible to always obtain an image having a stable density regardless of variations in the sensitivity of the thermal recording material S. Further, since the thermosensitive recording material S can be always preheated to the temperature immediately before color development, the sensitivity can be increased.

In this embodiment, the acousto-optic modulator 26
The case where the output of the preheating laser 14 is modulated via the above is explained, but the semiconductor laser 1 is controlled by the control unit 42.
2 may be directly modulated to set the black border 44 to a predetermined blackening density, and it is preferable to use both of them together.

[0025]

According to the thermal recording apparatus of the present invention, the following effects can be obtained.

That is, the preheating means uniformly heats the outer portion of the image around the image portion to the coloring temperature or higher. The temperature control means detects the density of the outside portion of the image via a densitometer and controls the output of the preheating means and / or the heating means to adjust the density of the outside portion of the image to a predetermined density.
By adjusting the output of the preheating means and / or the heating means, the heat-sensitive recording material is preheated more accurately to the temperature immediately before the color development, and the heat-sensitive recording material is heated to the predetermined color development temperature by the heating means.

Therefore, an image having a stable density can always be obtained irrespective of variations in sensitivity of the thermal recording material.
Moreover, since the heat-sensitive recording material can be always preheated to a temperature immediately before color development, the sensitivity can be increased.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a thermal recording apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a scanning position on a thermosensitive recording material by a laser beam and a laser output.

[Explanation of symbols]

10 ... heat recording device 12 ... semiconductor laser 14 ... preheating laser 20 ... polygon mirror 26 ... acousto-optic modulator 36 ... concentration meter 42 ... controller 44 ... black borders S ... thermosensitive recording material T ₀ through T ₅ ... scanning position

Claims (1)

[Claims] 1. An image portion of a heat-sensitive recording material, which comprises a color developing agent, a color developing agent and a light absorbing dye on a support, and develops a color at a density according to applied heat energy, and at the same time preheats to a predetermined temperature lower than the color developing temperature. A preheating means for heating a portion outside the image around the image portion to a coloring temperature or higher; and supplying heat energy corresponding to the image to at least the image portion of the thermosensitive recording material to bring the thermosensitive recording material to a predetermined coloring temperature. A heating means for heating, a densitometer for detecting the density of the image outside portion of the heat-sensitive recording material heated to a color development temperature or higher by the preheating means, and a density detected by the densitometer to be a predetermined density, A thermal recording device, comprising: temperature control means for controlling the output of the preheating means and / or the heating means.