JPH11115248A - Image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high quality recording images having fine density gradation by a method wherein a recording means that records latent images by exposing photosensitive thermal development recording material is constructed, being equipped with a plurality of lasers and an exposure control part that controls the number of lasers to be used for exposure at least in accordance with sensitivity property of the recording material. SOLUTION: An image exposure part 16 of a recording apparatus is to expose a recording material A to develop images by means of light beam scanning exposure and is equipped with an exposure unit 46 and a vertical scanning carrying means 48. The exposure unit 46 is to shed a light beam L modulated in accordance with recording images for incident to a recording position X, deflecting in the horizontal scanning direction, and equipped with a main laser 50 available for exposure in the whole exposure energy range, a sub-laser 51 that is low in output and available for fine adjustment in variation of output, an exposure control device 52 for controlling each of the lasers 50 and 51, and a polygonal mirror 54. With control made so that exposure in the medium exposure energy range is executed by two of the lasers 50 and 51, fine density gradation can be obtained, making high quality image recording possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an image recording apparatus for recording an image on a photosensitive heat-developable recording material using laser beams emitted from a plurality of lasers.

[0002]

2. Description of the Related Art Conventionally, ultrasonic diagnosis, CT diagnosis, MR
Images taken by I diagnosis, X-ray diagnosis and the like are recorded on a silver halide photographic light-sensitive material to form a hard copy. However, while silver halide photographic materials can provide high-quality images, they require wet development processing such as color development, fixing bleaching, and washing with water. There is also a problem that maintenance of the (processor) is troublesome, and it is desired to output a hard copy by an image forming method that does not require a wet developing process.

As an image forming method that does not require wet processing,
Thermal image recording is known. As is well known, the thermal image recording uses a thermal head having a glaze in which heating elements are arranged in one direction (main scanning direction), and presses the glaze against the thermosensitive recording material. The image is recorded on the heat-sensitive recording material by generating heat in each heating element according to the recorded image while relatively moving in the orthogonal direction. The image quality of such thermal recording images has been greatly improved in recent years. Recently, in addition to recording of ultrasonic diagnostic images conventionally used, CT diagnosis, MRI diagnosis,
Use for applications requiring large and high-quality images, such as line diagnosis, is also being studied. However, in terms of recording density and gradation reproducibility, an image formed by exposing a silver halide photographic material with a light beam or the like is also advantageous.

As an image forming method which has solved such problems, attention has been paid to image recording using a photosensitive heat-developable recording material. The photosensitive heat-developable recording material is a recording material that develops a color by heating an exposed area or a non-exposed area, and forms a latent image by imagewise exposing the photosensitive heat-developed recording material by a light beam or the like, By heating the exposed photosensitive material, an exposed area or a non-exposed area is colored and visualized, and a hard copy in which an image is recorded as a visible image can be obtained. According to the image recording using such a photosensitive heat development recording material, a high-definition high-quality image using a light beam scanning exposure or the like can be formed without performing a wet development process.

[0005]

By the way, digital image recording on a photosensitive heat-developable recording material (hereinafter, referred to as a recording material) is performed by using one laser modulated in accordance with digital image data to be recorded. This is performed by conveying the recording material, which is the object to be scanned, in the sub-scanning direction in a direction substantially perpendicular to the main scanning direction while performing scanning exposure.

[0006] However, photosensitive recording materials including the above-mentioned photosensitive heat-developable recording material, that is, photosensitive materials, are generally either a negative photosensitive material or a positive photosensitive material, and have a non-linear characteristic curve. have. For example, as shown by the characteristic curves in FIGS. 4A and 4B, the negative photosensitive material and the positive photosensitive material have a low exposure energy range (hereinafter, referred to as a low exposure energy range) in the exposure dynamic range. In a high exposure energy range (hereinafter, referred to as a high exposure energy range), the amount of change in density with respect to the amount of change in exposure energy is small, that is, the absolute value | γ | On the other hand, in a medium exposure energy range (hereinafter referred to as a medium exposure energy range), the amount of change in density with respect to the amount of change in exposure energy is large, that is, the absolute value | γ of the gradient γ
Is large, so that a so-called gradation is obtained, resulting in sensitivity / density characteristics. So, of course,
For the same change in exposure energy, the change in density in the middle exposure energy range is larger than the change in density in the low exposure energy range and high exposure energy range. Therefore, when setting the exposure energy of the laser for digital image data of a predetermined number of gradations (predetermined number of bits n) over the entire density range, it is necessary to perform finer control in the medium exposure energy range than in the high and low exposure energy ranges. There is.

However, in a high-power laser capable of outputting the entire range of exposure energy capable of reproducing the entire density range of the photosensitive material, the minimum unit of stable output adjustment (the minimum amount of change in exposure energy that can be adjusted) is limited. There is a problem that the density corresponding to the digital image data cannot be reproduced. On the other hand, in the case of a low-power laser, the minimum unit for stable output adjustment can be finely adjusted to correspond to digital image data, but since the sensitivity of the photosensitive material is limited, naturally, the entire density range of the photosensitive material is limited. Cannot be reproduced.

In other words, in other words, the sensitivity of the photosensitive material /
In the density characteristics, since the density resolution is different between the middle exposure energy region where the gradation is standing and the low and high exposure energy regions where the gradation is falling, a medium-low output laser with sufficient resolution in the middle exposure energy region On the other hand, there is a problem that a laser which covers the entire density range cannot obtain a sufficient density resolution in a medium exposure energy region where gradation is raised. For this reason, there is a problem that such a laser cannot perform high-quality image recording in which a desired density is sufficiently developed.

An object of the present invention is to solve the above-mentioned problems of the prior art, and an image recording apparatus for recording a digital image on a photosensitive heat-developable recording material by using a laser is provided.
It is an object of the present invention to provide an image recording apparatus capable of obtaining fine density gradations over all densities and obtaining a high-quality recorded image in which a desired density is sufficiently developed.

[0010]

In order to achieve the above object, the present invention provides a method for exposing a photosensitive heat-developable recording material with a laser beam modulated according to digital image data of an image to be recorded. Recording means for recording a latent image, sub-scanning conveyance means for conveying the photosensitive heat-developable recording material in a predetermined sub-scanning conveyance direction while holding the recording material at a predetermined recording position, and a photosensitive medium on which the latent image is recorded. An image recording apparatus, comprising: a heat developing section for thermally developing a heat-developable recording material, wherein the recording means comprises a plurality of lasers and a laser used for exposure in accordance with at least sensitivity characteristics of the photosensitive heat-developable recording material. And an exposure control unit for controlling the number of lines.

Here, the exposure control unit uses the plurality of lasers in an exposure energy region where the change in sensitivity characteristics of the photosensitive heat-developable recording material is large, and in an exposure energy region where the change in sensitivity characteristics is small. It is preferable to control so as to use one or a smaller number of lasers than the plurality of lasers.

Further, one of the plurality of lasers is a main laser capable of exposing the entire exposure energy range of the photosensitive heat-developable recording material, and the other lasers are higher than the main laser. The sub-laser also has a low output, and the amount of change in the output can be finely adjusted. The exposure control unit controls the total exposure energy of the main laser and the sub-laser to It is preferable to control the recording material so that the energy is equal to the energy required for color development at a desired density.

The photosensitive heat-developable recording material has a support formed in a sheet shape and an image forming layer provided on the support, wherein the image forming layer is 50% or more of a binder. Is preferably a layer composed of latex and containing an organic silver salt and a reducing agent for the organic silver salt.

Further, the photosensitive heat-developable recording material has a support formed in a sheet shape and a light-sensitive heat-sensitive recording layer provided on the support. In addition to the electron-donating colorless dye encapsulated in the microcapsules and, in addition to the thermoresponsive microcapsules, a compound having an electron acceptor and a polymerizable vinyl monomer in the same molecule, and a photopolymerization initiator. Layer, or a layer containing an electron-donating colorless dye encapsulated in a thermoresponsive microcapsule, and, in addition to the thermoresponsive microcapsule, an electron accepting compound, a polymerizable vinyl monomer, and a photopolymerization initiator It is preferred that

Furthermore, it is preferable that the plurality of lasers are semiconductor lasers.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image recording apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a schematic diagram showing an example of the image recording apparatus of the present invention. The image recording device 10 shown in FIG.
A device that is preferably used as a so-called medical imager for producing a print that reproduces an image measured by a medical measuring instrument such as CT or MRI as a visible image, and is a photosensitive device using a transparent film as a support. Using a heat-developed recording material A (hereinafter referred to as recording material A), the recording material A is scanned and exposed by a light beam L modulated according to image data supplied from an image data supply source R such as MRI. After the exposure, a latent image is recorded, the exposed recording material A is heated and developed to form a color, and is output as a hard copy on which an image is formed.

As one of the photosensitive heat-developable recording materials preferably used in the recording apparatus 10 of the present invention, 50% or more of a binder is formed of latex on one surface of a support,
A light- and heat-sensitive recording material (hereinafter, referred to as a first recording material) having an image forming layer containing an organic silver salt and a reducing agent for the organic silver salt is exemplified. In the first recording material, a photocatalyst such as photosensitive silver halide forms a latent image nucleus when exposed to light, and when heated, the silver of the organic silver salt ionized by the action of the reducing agent is formed. Move to combine with the photosensitive silver halide to form crystalline silver, forming an image,
It is a negative photosensitive material. The first recording material is described in detail in Japanese Patent Application No. Hei 9-185724 by the present applicant.

The organic silver salt contained in the image forming layer of the first recording material is relatively stable to light, but is exposed to an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent. A silver salt that forms a silver image when heated to 80 ° C. or higher in the presence of, and may be desalted as necessary. Such organic silver salts include a silver salt of an organic acid, preferably a silver salt of a long-chain fatty carboxylic acid having 10 to 30 carbon atoms, and a complex stability constant having a ligand of 4.0 to 10.0. Complexes of organic or inorganic silver salts having, for example, silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, maleate Silver acid, silver fumarate and the like are exemplified.

Further, as the organic silver salt, a silver salt of a compound containing a mercapto group or a thione group and derivatives thereof can be suitably used, and specifically, 3-mercapto-4-phenyl-1,2,3 Thioglycolic acid such as 2,4-triazole, 2-mercaptobenzimidazole, dithiocarboxylic acid such as dithioacetic acid, thioamide, 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, mercaptotriazine, 2-mercaptobenzoxazole And the like.

The shape of such an organic silver salt is preferably a needle-like crystal having a short axis and a long axis. Specifically, the short axis is 0.01 μm to 0.20 μm, and the long axis is 0.10 μm to 5.0 μm.
0 μm is more preferred. Further, the organic silver salt is preferably monodispersed. Specifically, the standard deviation of the length of each of the short axis and the long axis is divided by the short axis and the long axis to be 100.
Preferably, the fraction is 100% or less.

Such an organic silver salt is used to obtain polyacrylic acid,
It is preferable to use a known dispersant such as polyvinyl alcohol and polyvinylpyrrolidone to obtain a solid fine particle dispersion. The dispersion of the organic silver salt into solid fine particles may be performed by a known mechanical fine particle dispersion method using a ball mill, a vibration ball mill, or the like in the presence of a dispersant. In addition to the mechanical dispersion method, the pH may be controlled so that the particles are roughly dispersed in the solvent, and then the pH is changed in the presence of a dispersing agent to form fine particles.

The amount of the organic silver salt is 0.1 to 5 g / silver.
l is preferable, and more preferably 1 to 3 g / l.

The reducing agent for reducing such an organic silver salt is as follows:
Any substance that can reduce silver ions to metallic silver can be used, and is preferably an organic substance, such as organic silver disclosed in JP-A-6-3793 and US Pat. No. 5,464,738. Various known reducing agents used for light- and heat-sensitive recording materials using salts can be used. Specifically, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis (2 -T-butyl-6-methylphenol), 1,1-
Bis (2-hydroxy-3,5-dimethylphenyl)-
Bisphenols such as 3,5,5-trimethylhexane, chromanol, and hindered phenol reducing agents are suitably excited.

The reducing agent may be added by a method such as a solution, a powder, or a dispersion of solid fine particles. The amount of the reducing agent is preferably about 5 to 50 mol% based on 1 mol of silver on the surface having the image forming layer. The reducing agent is basically added to the image forming layer,
Another layer on the side having the image forming layer may be used, and in this case, it is preferable to use a relatively large amount of 10 to 50 mol% with respect to 1 mol of silver. Further, the reducing agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

The image forming layer of the first recording material contains a substance that becomes a photocatalyst upon exposure, for example, a photosensitive silver halide (hereinafter, referred to as silver halide). The halogen composition of the silver halide is not limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. And silver iodobromide are preferably used. The silver halide particle diameter of the recording material used in the present invention is 0.20 μm or less. Also,
In order to suppress white turbidity after image formation, the particle diameter is set to 0.1.
It is preferably 20 μm or less, particularly cubic particles,
Tabular grains are preferred.

The silver halide grains include rhodium, rhenium, ruthenium, osnium, iridium, cobalt,
It is preferable that at least one complex of a metal selected from mercury or iron is contained in an amount of about 1 nmol to 10 mmol per 1 mol of silver. The silver halide grains are preferably chemically sensitized by a known method such as a sulfur sensitization method or a selenium sensitization method.

The amount of the silver halide to be used is preferably 0.01 mol to 0.5 mol per 1 mol of the organic silver salt.

In the first recording material, the image forming layer having such a composition is prepared by dispersing a latex obtained by dispersing a water-insoluble hydrophobic polymer as fine particles in a water-soluble dispersion medium, in an amount of 50 wt. % Or more. Alternatively, if necessary, other layers may have the same configuration. For such latex, see "Synthetic Resin Emulsion (edited by Tadashi Okuda and Hiroshi Inagaki, published by Kobunshi Kankokai (1
978))), “Applications of Synthetic Latex (Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, edited by Polymer Publishing Association (1993))”, “Chemistry of Synthetic Latex (Souichi Muroi, Polymer Publishing Association) Issuance (1970))).

Examples of such latex polymers include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins,
Examples include vinylidene chloride resin and polyolefin resin. The molecular weight of the polymer is 5000 to 10000000 in number average molecular weight.
And preferably about 10,000 to 100,000. If the molecular weight is too small, the mechanical strength of the photosensitive layer is insufficient,
If the size is too large, the film-forming property is poor, which is not preferable.

Specific examples of such a polymer include methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer,
Styrene / butadiene / acrylic acid copolymer, styrene / butadiene / divinylbenzene / methacrylic acid copolymer, methyl methacrylate / vinyl chloride / acrylic acid copolymer and the like are exemplified. In addition, various commercially available polymers can be used, for example, acrylic resin such as Sebian A-4635 manufactured by Daicel Chemical Industries, Ltd., and polyester resin such as FINE manufactured by Dainippon Ink and Chemicals, Inc.
TEX ES650, etc .; HYDRAN AP10, etc., manufactured by Dainippon Ink and Chemicals, Ltd. as a polyurethane resin; LACSTAR 7310K, etc., manufactured by Dainippon Ink and Chemicals as a rubber-based resin;
As vinylidene chloride resin, L manufactured by Asahi Kasei Corporation
502 and the like, and examples of polyolefin resin include Chemipearl S124 manufactured by Mitsui Petrochemical Co., Ltd.
These polymers may be used alone or as a blend of two or more.

The average particle size of the dispersed particles in the latex is 1 to
The range is preferably 50,000 nm, more preferably about 5 to 1,000 nm. There is no particular limitation on the particle size distribution of the dispersed particles, and a material having a wide particle size distribution or a material having a monodispersed particle size distribution may be used. Minimum film formation temperature of latex (MF
T) is −30 ° C. to 90 ° C., more preferably 0 ° C. to 70 ° C.
Is preferred.

As described above, in the image forming layer of the first recording material, it is preferable that 50% by weight or more of the total binder is latex, and that 70% by weight or more is latex. If necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose, or hydroxypropylmethylcellulose may be added to the image forming layer in a range of 50% by weight or less of the total binder. good. Further, the dispersed particles (polymer) of the latex are 2
It is preferable that the equilibrium water content at 5 ° C. and 60% RH is 2 wt% or less, more preferably 1 wt% or less.

Such a first recording material may have various layers other than the above-described image forming layer. For example,
A surface protective layer for the purpose of protecting the image forming layer and preventing adhesion,
An antihalation layer, a back (coat) layer formed on the surface of the support opposite to the image forming layer, and a backside resistive heating layer formed on the same surface as the back layer
ayer), an antistatic or conductive layer, a deposited metal layer and the like.

The image forming layer of the first recording material or another layer on the same surface as the image forming layer may further include a toning agent, a sensitizing dye, an antifoggant, Agents, stabilizer precursors, benzoic acids for the purpose of increasing sensitivity and preventing fogging, mercapto compounds and sisulfide compounds for the purpose of suppressing or accelerating development, improving spectral sensitization efficiency, and improving storage stability before and after development Known additives contained in recording materials, such as thione compounds, dyes and pigments for the purpose of improving color tone, preventing irradiation, plasticizers, lubricants, ultra-high contrast agents, high-contrast accelerators, hardeners, etc. May be contained.

As another example of a suitable recording material A used in the present invention, the following recording materials are exemplified. This photosensitive heat-developed (thermochromic) recording material (hereinafter referred to as a second recording material) is a recording material in which a photosensitive and thermosensitive (thermochromic) image forming layer is provided on a support. A compound having an electron-accepting colorless dye encapsulated in a thermoresponsive microcapsule, a compound having an electron acceptor and a polymerizable vinyl monomer in the same molecule in addition to the thermoresponsive microcapsule, and a photopolymerization initiator The recording material contains: Further, as another photosensitive / thermosensitive recording material (hereinafter, referred to as a third recording material), a recording material in which a photosensitive / thermosensitive (thermochromic) image forming layer is provided on a support, wherein the image forming layer is It is a recording material containing an electron-donating colorless dye encapsulated in heat-responsive microcapsules, and an electron-accepting compound, a polymerizable vinyl monomer, and a photopolymerization initiator in addition to the heat-responsive microcapsules.

The second and third recording materials cure the composition (hereinafter referred to as a photocurable composition) outside the thermoresponsive microcapsules by exposure to light, and are fixed. As a result, the compound having mobility (not immobilized) having the electron accepting portion and the polymerizable vinyl monomer portion or the electron accepting compound moves in the image forming layer, and the electron donating property in the microcapsule is changed. Is a recording material that forms an image by developing a colorless dye of the formula (1). Both recording materials are disclosed in Japanese Patent Application No. 8-3337 by the present applicant.
No. 24 describes this in detail.

The compound having an electron accepting portion and a polymerizable vinyl monomer portion in the same molecule, which is used in the photocurable composition of the second recording material, refers to an electron accepting group and a vinyl group in one molecule. Is a compound containing Specifically, styrenesulfonylaminosalicylic acid, vinylbenzyloxyphthalic acid, zinc β- (meth) acryloxyethoxysalicylate, vinyloxyethyloxybenzoic acid, β- (meth) ataacryloxyethylorselinate, β- ( (Meth) acryloxyethoxyphenol, β- (meth) acryloxyethyl-β-resorcinate, hydroxystyrenesulfonic acid-N-ethylamide, β- (meth) acryloxypropyl-p-hydroxybenzoate,
(Meth) acryloxymethylphenol, (meth) acrylamidopropanesulfonic acid, γ-styrenesulfonyloxy-β- (meth) acryloxypropanecarboxylic acid, and the like, and a metal salt thereof, for example, a zinc salt can be preferably used.

The above compound can be suitably used also as a polymerizable vinyl monomer of the photocurable composition of the third recording material. In addition, as the polymerizable vinyl monomer used in the third recording material, various monomers having at least one vinyl group in a molecule can be used.
For example, (meth) acrylic acid and its esters,
(Meth) acrylamides; maleic anhydride, maleic esters; itaconic acid, itaconic esters; styrenes; vinyl ethers and esters; N-vinyl heterocycles; allyl ethers and esters. In particular, a monomer having a plurality of vinyl groups in the molecule is preferable. For example, (meth) acrylates of polyhydric alcohols, polyhydric phenols, (meth) acrylates of bisphenols, and (meth) acrylate-terminated epoxy There are resins and (meth) acrylate-terminated polyesters. Specifically, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hydroxypentaacrylate, hexanediol-1,5-dimethacrylate,
Examples thereof include diethylene glycol dimethacrylate. These monomers have a molecular weight of about 100 to about 500.
Those having about 0 are preferably used.

The photopolymerization initiator used in the second and third recording materials is a compound capable of initiating the photopolymerization of the vinyl monomer, and is preferably used in combination with a green, red to infrared absorbing dye. In addition, it is said that it has sensitivity in this wavelength region and generates radicals upon irradiation with light (Japanese Patent Application Laid-Open No.
No. 143044) Organic borate salt compounds, more preferably organic borate salts of cationic dyes. The organic borate generates a radical in response to the irradiated laser beam, and the radical initiates the polymerization of the vinyl monomer portion.

As the organic borate salt, a compound represented by the following general formula (1) is used.

Embedded image

In the above general formula (1), M is
Li metal atom, quaternary ammonium, pyridinium, quino
Linium, diazonium, morpholinium, tetrazoli
, Acridinium, phosphonium, sulfonium,
Oxosulfonium, sulfur, oxygen, carbon, halogeniu
, Cu, Ag, Hg, Pd, Fe, Co, Sn, M
cation selected from o, Cr, Ni, As, Se
N is an integer of 1 to 6, R ¹, R^Two, R^ThreeAnd R^Four
Each represents a halogen atom, a substituted or unsubstituted alkyl
Group, substituted or unsubstituted alkenyl group, substituted or unsubstituted
Substituted alkynyl group, alicyclic group, substituted or unsubstituted ant
Alkenyl group, substituted or unsubstituted alkaryl group,
Is an unsubstituted aryloxyl group, a substituted or unsubstituted
Alkyl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted
Represents a substituted silyl group. Where R¹, R^Two, R^ThreeAnd
And R^FourMay be the same or different from each other, and these
Of these, two or more groups may be bonded to form a cyclic structure.

In the above general formula (1), examples of the borate anion include tetraethyl borate, triisobutyl methyl borate, di-n-butyl-di-t-butyl borate, tetraphenyl borate, tetra-p-chlorophenyl borate, and tri-borate. m-chlorophenyl-n-hexyl borate, triphenylethyl borate, trimethylbutyl borate, tolyl isopropyl borate,
Triphenylbenzyl borate, tetraphenyl borate, tetrabenzyl borate, triphenylphenethyl borate, triphenyl-p-chlorobenzyl borate, triphenylethenituburiborate, di (α-nephthyl) -dipropyl borate, triphenylsilyl triphenyl Examples thereof include borate, tritolylsilylphenyl borate, and tri-n-butyl (dimethylphenylsilyl) borate.

The following is an example of the organic borate salt represented by the general formula (1).

Embedded image

In order to increase the light absorption efficiency of the recording light L or the like,
The organic borate salt represented by the general formula (1) is preferably used as a spectral sensitizing dye in combination with green to red and infrared absorbing dyes. Particularly, the maximum absorption wavelength is 500 to 1
Organic cationic dyes having a wavelength range of 100 nm are preferably used, and specifically, cationic methine dyes,
Examples include a cationic carbonium dye, a cationic quinone imine dye, a cationic indoline dye, and a cationic styryl dye. More specifically, as the cationic methine dye, polymethine dye, cyanine dye, azomethine dye, more preferably cyanine, carbocyanine, dicarbocyanine, tricarbocyanine, hemicyanine, etc., as a cationic carbonium dye , A triarylmethane dye, a xanthene dye, an aridudine dye, more preferably rhodamine, etc., and as the cationic quinone imine dye, a dye selected from azine dyes, oxazine dyes, thiazine dyes, quinoline dyes, thiazole dyes, These can be used alone or in combination of two or more.

The photopolymerization initiator is more preferably
An organic borate salt of a cationic dye represented by the following general formula (2) is used.

[0047]

Embedded image

In the above formula (2), D ⁺ represents a cationic dye, and R ¹ , R ² , R ³ and R ⁴ are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl. Group, substituted or unsubstituted aralkyl group, substituted or unsubstituted alkaryl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted alkynyl group, substituted or unsubstituted aryloxyl group, substituted or unsubstituted allylic group It is a group selected from a click group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted allyl group, a substituted or unsubstituted silyl group, and an alicyclic group. Also,
R ¹ , R ² , R ³ and R ⁴ may be the same or different from each other, and two or more of these groups may be bonded to form a cyclic structure.

In the above general formula (2), the cationic dye represented by D ⁺ acts as a spectral sensitizing dye, and has a wavelength range of 500 nm or more, particularly 550 nm to 550 nm.
An organic cationic dye having an absorption peak in a wavelength region of 1100 nm is preferably exemplified. Specifically, as such an organic cationic dye, those exemplified for the compound of the general formula (1) can be suitably used. Further, as the borate anion, the same ones as in the general formula (1) are preferably exemplified.

An example of the organic borate salt of the cationic dye represented by the general formula (2) is shown below.

Embedded image

[0051]

Embedded image

The content of these photopolymerization initiators is preferably 0.01% by weight to 20% by weight based on the total weight of the photocurable composition (outside of the thermoresponsive microcapsules).

In both recording materials, 2-phenyl-4,6-bis (trichloromethyl) -S-triazine and 2- (p-chlorophenyl) -4 were used together with the above-mentioned photopolymerization initiator and spectral sensitizing dye. , 6-Bis (trichloromethyl)-
S-triazine, 2- (p-methoxyphenyl) -4,
6-bis (trichloromethyl) -S-triazine, carbon tetrachloride, carbon tetrabromide, iodoform, p-nitro-α,
A compound having an active halogen group in the molecule, such as α, α-tribromoacetophenone, can be used in combination as an auxiliary. These compounds are preferably added in an amount of 0.01 to 20 mol based on 1 mol of the spectral sensitizing dye (cationic dye).

An electron-accepting compound is added to the photocurable composition of the third recording material. Further, the photocurable composition of the second recording material may also be added with an electron-accepting compound, if necessary, to improve the color density.
Examples of the electron accepting compound include phenol derivatives such as 2,2'-bis (4-hydroxyphenyl) propane, 4-t-butylphenol, and 4-phenylphenol;
Salicylic acid derivatives such as pentadecylsalicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (tert-octyl) salicylic acid, metal salts of aromatic carboxylic acids, acid clay, bentonite, novolak resins, Metal-treated novolak resins, metal complexes, and the like. These electron accepting compounds are preferably used in an amount of about 5% by weight to about 1000% by weight of the colorless electron donating dye.

The photocurable composition of such a recording material has, in addition to these compounds, a photocrosslinkable composition such as polyvinyl cinnamate, polyvinyl cinnamylidene acetate, and α-phenylmaleimide group. You may add a photocurable composition etc. Further, these photocrosslinkable compositions may be used as photocurable components. Furthermore, in the photocurable composition, in addition to these compounds, if necessary, to prevent thermal and temporal polymerization of the photocurable composition, with the aim of enhancing stability , P-methoxyphenol, hydroquinone, pyrogallol, 2-hydroxybenzophenone, cuprous chloride and the like may be added. These are present in an amount of 0.1% based on the total weight of the photocurable composition.
It is preferable to add about 001% by weight to 5% by weight.

The photocurable composition is emulsified and dispersed and contained in the image forming layer. Solvents used for emulsifying and dispersing the photocurable composition include cottonseed oil, kerosene, aliphatic ketone, aliphatic ester, paraffin, naphthenic oil, alkylated biphenyl, chlorinated paraffin, phosphate esters such as diphenyl phosphate, and acetyl. Citrate esters such as tributyl citrate; benzoic esters such as octyl benzoate; (meth) such as methyl (meth) acrylate
Examples thereof include acrylates, alkyl halides such as methylene chloride and carbon tetrachloride, and methyl isobutyl ketone. Aliphatic esters and alkyl halides are preferred, and those having a solubility in water of 10% by volume or less are more preferred. These solvents are used for the photopolymerizable compound.
It is preferably used in a proportion of from 500 parts by weight to 500 parts by weight.

As the water-soluble polymer that can be used for emulsifying and dispersing the photocurable composition, a compound that is soluble in water at 25 ° C. in an amount of 5% by weight or more is preferable. Derivatives, proteins such as albumin, cellulose derivatives such as methylcellulose, sugar derivatives such as starches (including modified starch), polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide, saponified vinyl acetate-polyacrylic acid copolymer, Synthetic polymers of polystyrene sulfonate sugars are mentioned, and gelatin and polyvinyl alcohol are particularly preferable.

On the other hand, as the electron-donating colorless dye encapsulated in the microcapsules of the image forming layers of both recording materials, various conventionally known dyes can be used. In particular,
Triphenylmethanephthalide-based compounds such as 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, leuco-auramine-based compounds such as N-halophenyl-leuco-auramine, rhodamine-B-anilino Lactams and other rhodamine lactam compounds; 2- (dibenzylamino) fluoran and other fluoran compounds; phenothiazine compounds such as benzoyl leuconmethylene blue; spiropyran compounds such as 3-methyl-spiro-dinaphthopyran; Various compounds can be used, such as a sulfide compound, a totaphenylmethane compound, a triazene compound, and a fluorene compound. When this recording material is a full-color recording material, U.S. Pat. No. 4,900,149 is used as an electron-donating colorless dye for cyan, magenta, and yellow, and U.S. Pat. , 80
0,148, etc., and JP-A-63-53542, etc., for the cyan coloring type.

Microcapsules containing such an electron donating colorless dye can be obtained by a method known in the art. For example, an interfacial polymerization method disclosed in Japanese Patent Publication No. 42-771, a method by precipitation of a polymer disclosed in U.S. Pat. No. 3,660,304, and a method disclosed in U.S. Pat. No. 3,796,669. Method using the disclosed isocyanate polyol wall material, U.S. Pat.
A method using an isocyanate wall material disclosed in 914,511, a method using a urea formaldehyde-resorcinol-based wall forming material disclosed in U.S. Pat. No. 4,089,802, and the like are disclosed. Especially,
It is preferable to form a polymer film as a microcapsule wall after emulsifying the core substance.

In particular, a microencapsulation method by polymerization of a reactant from the inside of an oil droplet is preferable in that a recording material having a capsule having a uniform particle size and excellent storage stability can be obtained within a short time. For example, when polyurethane is used as a capsule wall material, a polyvalent isocyanate such as m-phenylene diisocyanate or 2,6-tolylene diisocyanate and a second substance which reacts therewith to form urethane (capsule wall) (for example, Polyols such as aliphatic or aromatic polyhydric alcohols and polyamines such as ethylenediamine and trimethylenediamine) are mixed in an oily liquid to be encapsulated, emulsified and dispersed in water, and then the temperature is increased. A polymer formation reaction occurs to form microcapsule walls. At this time, an auxiliary solvent having a low boiling point and strong dissolving power can be used in the oily liquid.

The microcapsules can also be prepared using water-soluble polymers such as water-soluble anionic polymers, nonionic polymers and amphoteric polymers. Arabic gum, alginic acid, sulfated starch,
Sulfated cellulose, (meth) acrylic acid-based (co) polymer, carboxy-modified polyvinyl alcohol and the like, nonionic polymers include polyvinyl alcohol and hydroxyethyl cellulose, and amphoteric compounds include gelatin and the like. , Gelatin, gelatin derivatives and polyvinyl alcohol are preferred. The water-soluble polymer is 0.0
It is used as a 1% to 10% by weight aqueous solution.

In such a thermochromic recording material, the average particle size of the capsule is 20 μm or less, and particularly preferably 5 μm or less from the viewpoint of resolution. On the other hand, if the capsule is too small, the surface area for a certain solid content becomes large, and a large amount of a wall material is required. Therefore, the thickness is preferably 0.1 μm or more. The colorless electron-donating dye may be present in a solution state in the microcapsule, or may be present in a solid state.

This thermochromic recording material may have various layers such as a protective layer and an intermediate layer in addition to the image forming layer. Further, in each layer of the image forming layer, the intermediate layer and the protective layer of the recording material, particularly in the protective layer, a curing agent, particularly, a gelatin hardening agent such as chrome alum or zirconium sulfate used in the production of photographic light-sensitive materials. It is preferable to use the agent in combination. Further, each layer of the thermochromic recording material has a coating aid,
For various purposes such as antistatic, smoothness improvement, emulsification dispersion, adhesion prevention, various surfactants such as ionic surfactants such as saponin and polyethylene oxide may be used.
In addition, various additives such as dyeing agents for preventing irradiation and halation, ultraviolet absorbers, plasticizers, optical brighteners, coating aids, antistatic agents and slipperiness improvers may be added. Good. In addition, it is preferable to add a known matting agent such as silica or polystyrene in the protective layer, and furthermore, colloidal silica such as Nissan Chemical's Snowtex series may be added to reduce the adhesiveness. ,
A fluorescent whitening agent for increasing the whiteness of the recording material or a blue dye as a bluing agent may be added.

The first, second and third recording materials having such characteristic image forming layers are prepared by preparing a coating solution (emulsion) containing the components of each layer by using a solvent, if necessary. It can be produced by applying and drying by a known means. As the solvent, various solvents used for producing the recording material can be used. Specifically, water, alcohols such as ethanol and isopropanol, halogen-based solvents such as ethylene chloride, ketones such as cyclohexanone and methyl ethyl ketone. , Esters such as methyl acetate cellosolve and ethyl acetate, toluene, xylene, etc. are exemplified.If necessary, a plurality of types may be used in combination. Various surfactants such as nonionic, anionic, cationic, and fluorine may be added. As a coating method, known methods such as a blade coater, a rod coater, a knife coater, a roll doctor coater, a reverse roll coater, a transfer roll coater, a gravure coater, a kiss roll coater, and a curtain coater can be used. In addition, the application amount of each paint,
Of course, the amount of adhesion of each layer after drying is adjusted to be a predetermined amount.

There is no particular limitation on the support of these recording materials, and various materials used for ordinary recording materials can be used. Specifically, polyester films, polyethylene terephthalate films, polyethylene naphthalate films And resin films such as cellulose nitrate film, cellulose ester film, polyvinyl acetal film and polycarbonate film, various metals such as aluminum, zinc and copper, glass and paper.

The recording apparatus 10 of the illustrated example is basically applied with the photosensitive material supply section 12, the width adjustment section 14, the image exposure section 16, and the heat developing apparatus of the present invention in the order of conveyance of the recording material A. And a discharge tray 80. Although not shown in FIG. 1 in order to simplify the drawing and clarify the configuration, the recording apparatus 10 includes a conveying roller and a guide for conveying the recording material A, in addition to the illustrated members. , Various sensors and the like are arranged as needed.

The recording material A is usually formed into a laminate (bundle) of a predetermined unit such as 100 sheets and wrapped in a bag or a band. Are supplied to the recording device 10 and supplied to the recording device 10 one by one. The photosensitive material supply unit 12 (hereinafter, referred to as a supply unit 12) supplies the recording material A from the magazine 20.
Are taken out and supplied to the width shifter 14 located downstream (hereinafter, referred to as downstream) in the transport direction of the recording material A. The loading units 22 and 24 and the suction cups 26 arranged in each loading unit And supply roller pairs 30 and 32 and transport roller pairs 34 and 36 using
And transport guides 38, 40 and 42.

The loading sections 22 and 24 are sections for loading the magazine 20 containing the recording material A at a predetermined position.
The illustrated recording apparatus 10 includes two loading units 22 and 24.
Usually, recording materials A having different sizes (for example, half-cut size for CT and MRI, B4 size for FCR (Fuji Computed Radiography), etc.) are stored in both loading sections. The magazine 20 is loaded.
The single-wafer means arranged in each loading section includes suckers 26 and 28
The recording material A is sucked and held, and the recording material A is conveyed by moving the suction cups 26 and 28 by a known moving means such as a link mechanism, and is supplied to the supply roller pairs 30 and 32 disposed in the respective loading sections. Supply. The recording material A supplied to the supply roller pair 30 is supplied to the conveyance guides 38 and 4.
The recording material A supplied to the supply roller pair 32 while being guided by the transport rollers 40 while the guide material 40 is guided by the transport guides 40 and 42. 14.

The width shifter 14 aligns the recording material A in a direction perpendicular to the conveying direction (hereinafter, referred to as a width direction), so that the recording material A in the main scanning direction in the downstream image exposure unit 16 is aligned. This is a position where the recording material A is conveyed to the downstream image exposure unit 16 by the conveyance roller pair 44 after alignment, that is, so-called side registration is taken. Width adjuster 14
There is no particular limitation on the method of the side resist in the above. For example, there is a resist plate for positioning by contacting one end face in the width direction of the recording material A, and the recording material A is pushed in the width direction to move the end face to the resist plate. A method using a pressing means for abutting,
A method using a resist plate and a guide plate or the like movable in accordance with the size of the recording material A in the width direction, such that the conveying direction of the recording material A is regulated in the width direction and is similarly brought into contact with the resist plate, Various known methods are exemplified. In addition, the alignment of the recording material A in the width adjustment unit 14 may be performed using a so-called center resist that performs alignment with reference to the center of the recording material A.

The image exposing section 16 (hereinafter, referred to as the exposing section 16) is a portion for exposing the recording material A imagewise by light beam scanning exposure.
8 is provided.

FIG. 2 is a conceptual diagram of the exposure unit 16. The exposure unit 46 includes a light beam L modulated according to a recorded image.
Is a light beam scanning device which deflects light in a main scanning direction (a direction perpendicular to the paper surface in FIGS. 1 and 2) and makes the light incident on a predetermined recording position X.
, An exposure control device 52 for driving a mirror, a polygon mirror 54 as an optical deflector, an fθ lens 56,
8 is provided. The exposure unit 46 also includes a collimator lens and a beam expander for shaping the light beam L emitted from the light source, a surface tilt correction optical system, and the like.
Various members, such as an optical path changing mirror, arranged in a known light beam scanning device are arranged as necessary.

As described above, the photosensitive heat-developable recording material that is the recording material A is soft in the low exposure energy range or the high exposure energy range (that is, the absolute value | γ |
Is small), while the medium exposure energy region has a sensitivity / density characteristic of a high contrast (that is, a large absolute value | γ | of the gradient γ). Specifically, FIG. 3 shows an example of the relationship between the exposure energy E and the density D (after development) of the above-mentioned second recording material, which is a positive recording material. As shown in the figure, the gradient is steep in the middle exposure energy range, that is, the contrast is hard, and | γ | is large. In the case of a negative-type photosensitive heat-developable recording material, since the graph is substantially inverted from that of FIG. 3 in the left-right direction, the contrast is high in the middle exposure energy range as in the case of the positive type, and | γ |
Is big. Accordingly, in the sensitivity / density characteristics of the recording material A, the density resolution is different between the middle exposure energy region where the gradation is raised and the low and high exposure energy regions where the gradation is low.

For this reason, there is a problem that a laser which covers the entire density range cannot obtain a sufficient density resolution in a middle exposure energy range where gradation is raised. On the other hand, a medium-to-low output laser having a sufficient resolution in the medium exposure energy range has a problem that the entire density range cannot be covered.

On the other hand, according to the present invention, as shown in FIG. 2, two lasers 50 and 51 and an exposure control device 52 are provided.
By controlling the exposure of the recording material A at least in the medium exposure energy region where | γ | is large with two lasers 50 and 51, a fine density gradation can be obtained over all densities, and high image quality can be obtained. Thus, it is possible to perform an excellent image recording.

Here, the laser 50 (hereinafter referred to as the main laser 50)
) By combining the low exposure energy region and the high exposure energy region independently, and combining the medium exposure energy region with a laser 51 (hereinafter, referred to as a sub-laser 51).
This is for performing scanning exposure on the recording material A, and has an output corresponding to the dynamic range of the recording material A. The main laser 50 is not particularly limited as long as it emits a light beam L in a narrow band wavelength range according to the spectral sensitivity characteristics of the recording material A. The use of a laser is preferable in that it is small and is suitable for direct modulation, and can obtain light having a wavelength suitable for the spectral sensitivity characteristics of the recording material A. The wavelength of the laser 50 is not particularly limited.
The thickness is preferably 0 to 680 nm because it is suitable for forming a latent image from the viewpoint of the spectral sensitivity characteristics of the photosensitive heat-developable recording material, and particularly preferably 660 nm.

Laser 51 (hereinafter referred to as sub-laser 51)
Performs only exposure in the medium exposure energy range, and uses a laser whose maximum output is lower than the maximum output of the main laser 50. That is, by using such a low-output laser, the minimum controllable exposure energy unit ΔE (hereinafter, referred to as a minimum energy width ΔE) at the time of intensity modulation becomes smaller in accordance with a decrease in the maximum output. Finer energy control can be performed, and therefore a higher density resolution than the high-power main laser 50 can be obtained. The sub-laser 51 may be a laser having the same configuration as the above-described main laser 50 except that the sub-laser 51 has a low output, and is not particularly limited. Further, the number of sub-lasers 51 is one in the illustrated example, but is not limited to this, and may be configured to be two or more. For example, a total of three lasers, one main laser and two sub-lasers, may be used.

The maximum output of the sub laser 51 is
The recording material A is not particularly limited as long as it is lower than the maximum output of the recording material A.
In consideration of the characteristics described above, the value may be set to a value that can secure the minimum energy width ΔE required to obtain a desired high density resolution. Specifically, the output is preferably 30% to 70% of the maximum output of the main laser 50, and more preferably 50%. Within such a range, a high density resolution (for example, 2% at 50%) in the middle exposure energy range.
(Double density resolution) can be obtained, and the energy range of the middle exposure energy region can be sufficiently covered.

The exposure control device 52 performs gradation correction (density correction) on image data supplied from an image data supply source R such as MRI or CT, and performs laser correction based on the obtained image data, that is, a recorded image. 51 is configured to be driven by intensity modulation, and to emit a light beam L whose intensity is modulated according to a recorded image. Thus, the exposure control device 5
Numeral 2 directly modulates the main laser 50 and the sub-laser 51. The exposure in the low exposure energy range and the high exposure energy range is performed in the same manner as in the normal exposure. It is preferable to perform control using laser light so as to perform exposure by combining two laser lights emitted from the main laser 50 and the sub-laser 51 in the medium exposure energy range. The exposure may be controlled so as to be performed separately, continuously, or at intervals by the book laser.

More specifically, in the exposure in the middle exposure energy range, the sum E ₁ + E ₂ of the exposure energy E _{1 of the} main laser 50 and the exposure energy E ₂ of the sub-laser 51 is determined by the exposure corresponding to the desired density. (E)
_It suffices to drive both lasers 50 and 51 such that ₁ + E ₂ = E).

For example, the exposure energy E on the main laser 50 side
₁ is fixed to the upper limit value E _A low exposure energy range, a method of changing to replenish the remaining E-E _A in exposure energy E ₂ of the sub laser 51 side is preferably exemplified. These are summarized in Table 1. Thus, the sub-laser 51 having a higher density resolution than the high-power main laser 50
By performing exposure in the middle exposure energy range by combining the above, a sufficient density resolution can be obtained even in the middle exposure energy range and fine density gradation can be obtained as compared with the case where only the main laser 50 is used.

[0081]

As a mode of distributing the exposure energy E to the two lasers 50 and 51, the above-mentioned E ₁ + E ₂ =
As long as the relation of E is satisfied, the present invention is not limited to the above example, and E ₁ , E
Both _2, may be set to any value as long as it is within the range of the maximum output of the main laser 50 and the sub-laser 51, respectively.
For example, depending on the energy E to be exposed also in the middle exposure energy range of the exposure energy E ₁ is changed stepwise at a predetermined minimum energy width Delta] E _1, so as to supplement the shortage in exposure energy E _2, finer Minimum energy width ΔE ₂
(ΔE ₂ <ΔE ₁ ), and the total energy E
₁ + E ₂ is made equal to the desired exposure energy E (E ₁ +
The control may be performed such that E ₂ = E). further,
Of course, not only in the medium exposure energy range but also in the low exposure energy range or the high exposure energy range, the configuration may be such that the exposure is performed by combining the two lasers 50 and 51.

In either case, by performing such control, it is possible to record an image in the medium exposure energy range with a higher density resolution than in the case of one laser.
Accordingly, it is possible to perform high-quality image recording in which a desired density is sufficiently developed over the entire dynamic range of the recording material A.

In the image recording apparatus of the present invention,
The modulation method in image recording is not limited to the above intensity modulation, but may be pulse width modulation or pulse number modulation. As for the method of light modulation, AOM (acousto-optic modulator), EOM
(Electric engineering modulator) or external modulation using a modulation element such as a spatial modulation element such as a liquid crystal shutter array may be used.

The intensity of the laser 50, 5
1, two light beams L ₁ , L
₂ is deflected in the main scanning direction by the polygon mirror 54, adjusted by the fθ lens 56 to be multiplexed and imaged at the recording position X, changed in the optical path by the falling mirror 58, and is incident on the recording position X. . The recording device 10 in the illustrated example is a device that performs monochrome image recording, and the exposure unit 46 includes one set of lasers 50 and 51 (two in total).
However, when the present invention is used for recording a color image, for example, R (red), G
An exposure unit having three sets (six in total) of light sources that emit light beams having wavelengths corresponding to the spectral sensitivity characteristics of (green) and B (blue) may be used.

On the other hand, the sub-scanning conveying means 48
A pair of transport rollers 60 arranged with the (scanning line) interposed therebetween
The recording material A is conveyed in the sub-scanning direction (the direction of arrow a in FIG. 2) orthogonal to the main scanning direction while holding the recording material A at the recording position X by the conveying roller pairs 60 and 62. Here, as described above, the light beam L pulse-modulated in accordance with the recorded image is deflected in the main scanning direction, so that the recording material A is two-dimensionally scanned and exposed by the light beam to form a latent image. Is recorded.

The recording material A on which the latent image has been recorded in the exposing section 16 is then conveyed by conveying roller pairs 64 and 66 and the like, and conveyed to the heat developing section 18. The heat developing section 18 is for performing heat development by heating the recording material A to turn a latent image into a visible image, and has a heating drum 68, an endless belt 70, and a peeling claw 72. .

The heating drum 68 is a drum having a built-in heating element 69, the surface of which is heated and held at a temperature corresponding to the heat development temperature of the recording material A. The recording material A is configured to be pinched and conveyed together with the belt 70. The heating element 69 can heat the surface of the heating drum 68, and is turned on / off.
There is no particular limitation as long as it can be turned off, and a heating light source such as a halogen lamp and a heater are preferably exemplified.

The heat development time may be adjusted by changing the conveying speed according to the type of the recording material A. For example, when the recording material containing the latex (first recording material) is used as the recording material A, the heat development time is 10 seconds to 90 seconds, and the recording material containing the thermoresponsive microcapsules (the first recording material) is used. When the second recording material and the third recording material are used, the time is about 3 seconds to 60 seconds.

The endless belt 70 has rollers 74a,
It is stretched around four rollers 74b, 74c and 74d and is pressed so as to be wound around the heating drum 68. The peeling claw 72 applies the recording material A to the heating drum 68.
The recording material A is conveyed by the heating drum 68, and the recording material A is lightly contacted with and separated from the heating drum 68.

The thermal developing section 18 is not limited to the configuration shown in the drawings, but may be any other type as long as it can perform heating by bringing at least the recording material A into contact with the periphery of the heating drum 68. Can be adopted. For example, instead of the endless belt 70, rollers may be provided in multiple stages along the circumference of the heating drum 68, and the recording material A may be nipped and conveyed between the multiple rollers and the heating drum 68.

In such a thermal developing section 18, the recording material A conveyed by the conveying roller pair 66 is nipped and conveyed by the endless belt 70 and the rollers 76 and 78, so that the heating drum 68 and the endless belt 70 The latent image which has been carried in between and is thermally developed by the heating drum 68 while being conveyed in accordance with the rotation of the heating drum 68 becomes a visible image by exposure. Next, when the leading end of the recording material A is conveyed to the vicinity of the peeling claw 72, the peeling claw 72 lightly contacts the heating drum 68, and the heating drum 68
And the recording material A, and the recording material A is separated from the heating drum 68.

The recording material A peeled from the heating drum 68 by the peeling claw 72 after the thermal development by the heating drum 68 is completed in this way is transported out of the apparatus, and is converted into a tray as a hard copy from which an image is reproduced. It is discharged to 80.

Although the image recording apparatus of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

[0095]

As described in detail above, according to the image recording apparatus of the present invention, in image recording using a photosensitive heat-developable recording material, fine density gradation can be obtained over all densities. A high-quality recorded image in which a desired density is sufficiently developed can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an example of an image recording apparatus to which the present invention has been applied.

FIG. 2 is a schematic view of an example of an exposure section of the image recording apparatus shown in FIG.

FIG. 3 is a graph showing the relationship between exposure energy E and density D in a positive recording material.

FIG. 4A is an example of a characteristic curve of a negative photosensitive material, and FIG. 4B is an example of a characteristic curve of a positive photosensitive material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 (Image) recording device 12 (Recording material) supply part 14 Width adjustment part 16 (Image) exposure part 18 Thermal development part (Heating development apparatus) 20 Magazine 22, 24 Loading part 26, 28 Suction cup 30, 32 Supply roller pair 34 , 36, 44, 60, 62, 64, 66 transport roller pair 38, 40, 42 transport guide 46 exposure unit 48 scanning transport means 50 laser (main laser) 51 laser (sub-laser) 52 exposure controller 54 polygon mirror 56 fθ Lens 58 Falling mirror 68 Heating drum 68a Shaft 70 Endless belt 72 Peeling claw 74a, 74b, 74c, 74d, 76, 78 Roller 80 Discharge tray A Recording material

Claims (6)

[Claims] 1. A recording means for exposing a photosensitive heat-developable recording material with a laser beam modulated in accordance with digital image data of an image to be recorded to record a latent image, and said photosensitive heat-developable recording material. An image recording apparatus comprising: a sub-scanning conveyance unit configured to convey the latent image in a predetermined sub-scanning conveyance direction while holding the image at a predetermined recording position; An apparatus, wherein the recording unit includes a plurality of lasers and an exposure control unit that controls the number of lasers used for exposure according to at least a sensitivity characteristic of the photosensitive thermal development recording material. Image recording device. 2. The exposure control section uses the plurality of lasers in an exposure energy region where the change in sensitivity characteristics of the photosensitive heat-developable recording material is large. The image recording apparatus according to claim 1, wherein control is performed such that the number of lasers is smaller than the number of lasers. 3. A laser according to claim 1, wherein one of the plurality of lasers is a main laser capable of exposing the entire exposure energy range of the photosensitive heat-developable recording material, and the other laser is a main laser. And a secondary laser whose output is low and whose output change amount can be finely adjusted. The exposure control section determines that the total of the exposure energy of the main laser and the secondary laser is 3. The image recording apparatus according to claim 1, wherein the control is performed such that the energy required for color development of a desired density in the recording material is equalized. 4. The photosensitive heat-developable recording material has a support formed in a sheet shape, and an image forming layer provided on the support, wherein the image forming layer is 50% or more of a binder. Is an organic silver salt and a layer containing a reducing agent for the organic silver salt. 5. The photosensitive heat-developable recording material has a support formed in a sheet shape and a light- and heat-sensitive recording layer provided on the support. In addition to the electron-donating colorless dye encapsulated in the microcapsules and, in addition to the thermoresponsive microcapsules, a compound having an electron acceptor and a polymerizable vinyl monomer in the same molecule, and a photopolymerization initiator. Or a layer containing an electron-donating colorless dye encapsulated in a thermoresponsive microcapsule, and an electron accepting compound, a polymerizable vinyl monomer, and a photopolymerization initiator, in addition to the thermoresponsive microcapsule. The image recording apparatus according to claim 1, wherein 6. The image recording apparatus according to claim 1, wherein said plurality of lasers are semiconductor lasers.