JPH0233154A - Photoelectric photographic material and photoelectric photographic method - Google Patents

Abstract

PURPOSE:To eliminate stains from the background of a transferred image and to enhance image density and repeated reproducibility of image density by forming a layer containing a spiropyran compound and an electrically insulating binder. CONSTITUTION:The photoelectric photographic material used for a color proof is formed by coating a conductive substrate with a solution containing the spiropyran, such as a compound of formula and the insulating binder, such as polymethyl methacrylate, and drying it. In addition, the material may contain a sensitizer, an ultraviolet absorber, and the like. The image is formed by exposing the material to light through a screen negative, corona discharging it, color developing it with a toner, and transferring the toner image to a transfer paper, and the like method. In formula, each of R1-R3 is lower alkyl, R4 is H, halogen or the like; and each of R5 and R6 is H, nitro, or the like.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a photoelectrophotographic material and a photoelectrophotography method. The present invention relates to a photoelectrophotographic material that can provide a high-density transfer image without stains and is suitable for creating color proofs. [Background of the Invention] When printing a large number of sheets by creating a printing plate using a plate-making material such as a PS plate from a color original, the color original is usually converted into a 4-color halftone negative (or halftone) using a color scanner or the like. After creating a positive image, we go through processes such as pasting, reversing, and retouching, then create a 4-color 1-sheet positive, make a proof, check the finish, and then proceed to final printing. In this case, check functions such as checking the disassembly of the scanner in the process of creating a net negative or positive, checking pasting etc. in the process of creating a single-sheet positive, and checking the person who ordered the printing in the proof printing process are used to ensure a good print finish. Color proofs are created and checked for this purpose. Known photosensitive materials for creating color proofs include silver salt photosensitive materials, electrophotographic photosensitive materials, photosensitive materials using photopolymers, etc., and toner pigments, dyes, etc. Depending on the purpose of use, there are both negative-positive and positive-positive methods. Techniques for using a priori generators as photoresist imaging elements are known in the art. In such imaging processes, a priori generator is applied onto a support and then contacted with photopolymerizable or curable compositions such as epoxy resins and epoxy-containing resins. Upon imagewise exposure to actinic radiation, the prior generator generates protons in the exposed areas, and the protons perform a catalytic function in the polymerization or curing of the photopolymerizable composition; 1 For example, U.S. Pat. No. 4,081,272, 4,058
゜No. 401, No. 4,021,705, 2.8Q7441
No. 1, No. 4,089,055 4.529,480%. On the other hand, electrophotographic compositions and imaging processes are also known. In these processes, an electrophotographic layer coupled with a layer containing a photoconductor is electrostatically charged and then imagewise exposed to form an electrostatic latent image. The electrostatic latent image is developed with a toner composition. Electrophotographic elements and processes are described, for example, in U.S. Pat.
tL to be disclosed in the issue etc.? I/'ru. On the other hand, JP-A No. 113-2052 discloses a prior generator layer that (a) does not contain a photopolymerizable substance and (b) contains an electrically insulating binder and a prior generator; Techniques are disclosed using photoelectrophotographic materials having a conductive support in electrical contact with a layer. [Problems to be Solved by the Invention] However, in the method of JP-A No. 83-2052, the sensitivity is insufficient, and the difference in electrical resistance between the exposed and unexposed areas is insufficient, and it is difficult to prevent background smudges. It has been found that under conditions in which no image is produced, a high-density transferred image cannot be obtained, and on the other hand, under conditions in which a high-density transferred image is obtained, background smear tends to appear. It has also been found that there is a drawback that it is difficult to repeatedly obtain transferred images of the same density with good reproduction. Therefore, there was a problem in that the performance was insufficient for use as a color proof. Therefore, the present invention provides a method for forming a transferred image that can obtain a high-density transferred image without background smudge, can repeatedly obtain transferred images of the same density with good reproducibility, and can be suitably used as a color proof. The challenge is to provide the following.

[Means for Solving the Problems] The present inventor has completed the present invention as a result of intensive studies to solve the above problems. That is, the photoelectrophotographic material according to the present invention is characterized by having a layer containing a spiropyran compound and an electrically insulating binder on a conductive support. Further, the photoelectrophotographic method according to the present invention uses a photoelectrophotographic material having a layer containing a spiropyran compound and an electrically insulating binder on a conductive support, and performs imagewise exposure and electrostatic charging in any order or simultaneously. and then development with charged toner particles. 1 Effect] In the present invention, by using a spiropyran compound, the electrical resistance of the unexposed area is large and the initial charge is retained sufficiently high, and the decay rate of the charge is extremely low, while the electric charge of the exposed area is substantially reduced. Since the attenuation to zero is fast, the above-mentioned problem can be achieved, and at the same time, the unique effects of the present invention are exhibited. [Specific Structure] The photoelectrophotographic material of the present invention is characterized by having a layer containing a spiropyran compound and an electrically insulating binder on a conductive support. As the spiropyran compound, the compound shown in the following-Momonen [I] is used. General formula [11 In the formula, R1+ Re and Rs represent lower alkyl groups (which may be the same or different, respectively), R4 is a hydrogen atom,
Halogen atom, lower alkyl group, alkoxyl group, carboxyl group, alkoxycarbonyl group, nitro group or nitrile group, R6 and R6 hydrogen atom, halogen atom,
It represents a nitro group, an alkoxyl group, a formyl group, a carboxyl group, or an alkoxycarbonyl group. Examples of the compound represented by the above-mentioned - Monna [11] include the following. CIlkoC1l. Further, as the spiropyran compound of the present invention, the following compounds can also be used. Note that the spiropyran compound of the present invention may be used alone or in combination of two or more. Electrically insulating binders used in the present invention include polycarbonates, polyesters, polyolefins, phenolic resins, etc., or blends thereof. These binders preferably have film-forming properties, and 6
Those that can support electric fields in excess of 0.5 V/cm and exhibit low dark decay of charge are preferred. Useful binders include styrene-butadiene copolymers, silicone resins, styrene-alkyd resins, soy-
Alkyd resin, polyvinyl chloride. Polyvinylidene chloride, vinylidene chloride-acrylonitrile copolymers, polyvinyl acetate, vinyl acetate-vinyl chloride copolymers, polyvinyl acetals (e.g. polyvinyl butyral), polyacrylic esters and polymethacrylic esters (e.g. polymethyl methacrylate, polymethacrylic acid n- butyl, polyisobutyl methacrylate, etc.), polystyrene, nitrated polystyrene, polyvinylphenol, polymethylstyrene, inbutylene polymer, polyester (for example, phenol-formaldehyde resin), ketone resin, polyamide, polycarbonate, and the like. Other binders include paraffin,
There are substances such as ridges. In addition to the above-mentioned spiropyran compound and electrically insulating binder, a sensitizer may be added to the above layer as necessary. Specific examples of the sensitizer include benzoin, benzoin methyl ether, benzoin ethyl ether, 2,2-dimethoxy-2-phenylacetophenone, 9-fluorenone, 2-chloro-8-fluorenone, 2-methyl-8-
Fluorenone, 8-anthrone. 2-bromo-8-anthrone, 2-ethyl-8-anthrone, ! 3.10-anthraquinone, 2-ethyl-3
, 10-anthraquinone, 2-t-butyl-8,1O-
Anthraquinone, 2,8-dichloro-8,10-anthraquinone, xanthone, 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p-(dimethylamino)phenylstyryl ketone, p(dimethylamine) Phenyl p-methylstyryl ketone, benzophenone, p-(dimethylamino)benzophenone (or Michael's ketone), p
-(diethylamino)benzophenone, benzanthrone, and the like. The layer may also contain additives such as UV absorbers, plasticizers, dyes or pigments. The blending ratio of the composition of the above layer is preferably 1 part by weight or more of the spiropyran compound, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the entire layer, and preferably 89 parts by weight or less of the electrically insulating binder. . More preferably, it is 50-95 parts by weight, and the sensitizer is O-
30! The amount is preferably i parts, more preferably 0 to 20 parts by weight. Note that the above layer of the present invention contains a photopolymerizable substance. That is, it does not contain any photopolymerizable or photocrosslinkable compound. The conductive support of the present invention may be (1) a support that is entirely conductive, or (2) a support that has a conductive layer on the side in contact with the photoacid generator layer. The conductive support, the conductive layer, and the conductive portion may be formed by any method. is grounded. As the conductive support (2), metal sheet (preferably made of AIL or Cu), conductive paper, conductive polymer film, etc. are used, and as the support (1) having a conductive layer, for example, aluminum (1) is used. Vapor-deposited polyethylene terephthalate or the like is used, and the support on which the conductive portion (2) is formed may be, for example, a film or paper surface with Ai powder or Cu powder fixed by an appropriate means. To prepare the photoelectrophotographic material of the present invention, the spiropyran compound is dissolved in a suitable solvent in the presence of an electrically insulating binder. Then, if necessary, a sensitizer is dissolved in the resulting solution. and coated on a conductive support. Solvents include aromatic hydrocarbons such as benzene and toluene; 2-butanone; chlorinated hydrocarbons such as ethylene dichloride, trichloroethane and dichloromethane; ethers such as tetrahydroburan; or combinations of these solvents. There is a mixture. As a coating method, 1, for example, a normal coater such as a reverse roll coater, an air knife coater, a Meyer bar coater, etc.
Alternatively, it can be obtained by coating and drying using a spin coating device such as Whaler, or by dip coating. The thickness of this coating layer is preferably 0.1 to 50W, more preferably 1 to 25W. An example of the photoelectrophotographic material of the present invention is shown in FIG. 1, in which 1 is a conductive support and 2 is a layer containing a spiropyran compound. (1) The photoelectrophotographic material obtained above is set in a predetermined position, and imagewise exposed and charged as shown in FIG. After preparing a mesh negative of usually four colors from the original using a color scanner or the like, the mesh negative is inserted between an exposure source and a photoelectrophotographic material and exposed. As the exposure source, any actinic light such as a fluorescent lamp or a halogen lamp may be used, but it must provide a difference in resistance between the exposed area and the unexposed area. In the present invention, as shown in FIG. 2, the resistance of the exposed area 2A is about IQ12 to IQIsΩcm, the resistance of the unexposed area 2B is about IQ+4 to 1Q17Ωc+s, and the resistance ratio between the unexposed area and the exposed area is preferably at least 100. More preferably it is 100-500. Here, the resistance of the unexposed area is measured by the following method. An electrode is first deposited on the photopolymer surface, and the conductive surface between the photopolymer and polyethylene terephthalate is used as the back electrode. Resistance is measured on a sample of known area and coating thickness. A voltage is applied to the inner electrode and an electrometer is connected in series with the test tube. This electrometer allows accurate measurement of very small currents. The resistance is then calculated using the following formula: p = Rl / A = V l / IA where V is the voltage applied between the two electrodes, l is the measured current, is the thickness of the sample, and A is the area of the sample. The resistance of the exposed area is obtained from the measurement of the discharge time. For these measurements, two 2.54 cm diameter samples of the exposed material were mounted in a Monroe model 278 rotary charger connected to a Hewlett-Paracard computer for data acquisition. The samples were charged under a single wire corona device and the voltage held as a function of time was measured by an electrostatic multimeter. The discharge curve gives a direct value of the decay rate in unexposed material. The discharge rate is directly proportional to the resistance with the proportionality constant s/4π, where e is the dielectric constant and π is 3.1428. On the other hand, charging may be performed simultaneously with the above-mentioned exposure, before or after the exposure, and for example, a corona charger 3 is used as the charging method. The charging electrode used in the corona charger 3 is preferably a corotron, but may also be a scorotron. In the present invention, the unexposed area has high electrical resistance and retains a sufficiently high initial charge, and the rate of decay of that charge is not only extremely low; It expresses the character of being early. Therefore, the corona charger 3 forms an uncharged portion in the unexposed area 2B, and the electric charge in the exposed area 2A flows out to the outside via the ground tIi. An electrostatic latent image 3A is formed by the residual charge. (2) Next, toner development is performed (see FIG. 3). The toner 4 used is one charged with a charge opposite to the above-mentioned charge. This is because toner development can be easily performed by Coulomb force. As the toner used in the present invention, both known dry toner and liquid toner can be used. Liquid toner is preferred in terms of image quality. Liquid toners are colloidal suspensions of polymeric toner particles in a volatile, insulating carrier liquid. A primary example of a carrier liquid is an isoparaffinic liquid sold under the trade name Igopar G. The fine toner particles are usually made of a binder resin, such as styrene.
Consists of acrylic copolymer or polyester and pigment. The developer solution may contain an ionic charge control agent or stabilizer, which helps maintain the electrostatic charge on the toner particles.The developer solution may contain a dispersed wax to give the toner self-fixing properties. A description of toners of this type which may be used in particular in carrying out the method of the invention is given in European Patent Application No. 088,084 (published January 11, 11184). In the present invention, to obtain a color image. Y (yellow) toner, M (magenta) toner, C
Development may be repeated using four types of toner: (cyan) toner and Bk (black) toner. (3) Next, the above toner image is transferred to a transfer material 5 (for example, paper, film, etc.) as shown in FIG. A transferred image is thereby obtained. [Effects of the Invention] According to the present invention, it is possible to obtain a high-density transferred image without background smudge, and it is also possible to repeatedly obtain transferred images of the same density with good reproducibility, so that a photoelectric photograph can be preferably used as a color proof. materials can be provided. [Examples] Examples of the present invention will be described below. 13.5 g polymethyl methacrylate, 9.1 Ig
0-jethoxyanthracene sensitizer and a mixed solvent of 70 g of dichloromethane and cyclohexane (mixing ratio 80/4
A general formulation consisting of 0) was mixed on a roll mill to ensure complete dissolution. 7g of this formulation. Combined with 0.1 g of a spiropyran compound of the invention or a comparative compound below. Each of these solutions was mixed with 0.
0254 mm knife onto a copper-coated polyester support and dried in an oven at 110° C. for about 5 minutes. The coated film was cut into 50 x 50 l samples for 15 second exposure to a high pressure Hg lamp. Solid image and density step tablet (manufactured by Nijika Co., Ltd.)
After exposure through a 1000 volt (Blet), the film was negatively corona charged for 60 seconds, followed by toning with positive toner for 80 seconds, and the toner image was transferred to white synthetic paper. The obtained images were evaluated as follows. (Sensitivity) Evaluation was made based on the number of steps on a density step tablet showing the same value as the density of the non-image area. A higher value indicates higher sensitivity. (Image Density) Indicates the value of the density of a solid image measured using a reflection densitometer (Macbeth RD514). A higher value indicates a better image. (2) (Background smudge) The density of the non-image area is measured using a reflection densitometer (Macbeth RD514). A lower value indicates a better image. ■ (Repeatability of the same density) When obtaining a large number of transferred images by repeating the same process in the example, the higher the number of 0 copies, which is indicated by the number of copies where the image density begins to deviate from the ±2% range, the more the number of repetitions will be. It shows that the reproducibility is good. The above results are shown in Table 1. [Comparative compound]

[Brief explanation of the drawing]

1 to 4 are schematic cross-sectional views showing an example of the photoelectrophotographic material of the present invention and an image forming method using the photoelectrophotographic material. 1: Conductive support 2: Prior generator layer 2A: Exposed area 2B = Unexposed area 3: Corona charger 3A: Charged charge 4: Toner 5: Transferred material Patent applicant Konica Co., Ltd. representative Attorney Nobuaki Sakaguchi

Claims (1)

[Claims] 1. A photoelectrophotographic material comprising a layer containing a spiropyran compound and an electrically insulating binder on a conductive support. 2. Using a photoelectrophotographic material having a layer comprising a spiropyran compound and an electrically insulating binder on a conductive support, imagewise exposure and electrostatic charging are carried out in any order or simultaneously, followed by development with charged toner particles. A photoelectrophotographic method characterized by: