JPH07104463A - Image forming material - Google Patents

Abstract

PURPOSE:To provide an image forming material capable of giving a transfer image resembling a printed matter as a pre-press proof for color correction. CONSTITUTION:Regarding an image forming material formed out of a photosensitive layer containing a coloring agent on a carrier, and a protective film laid thereon for exposing an image for transfer to an image receptor such as paper through a stickiness difference in the exposure and non-exposure sections in the photosensitive layer for transfer, the protective film is a polyolefine film having smoothed surface with a value of 0 or less as Z expressed by the discriminant of Z=-0.015W+H+0.315, where W stands for the maximum length of a projection existing on film surface, and H for the height of the projection. Furthermore, This image forming material uses polyolefine having suitable separability from the photosensitive layer and smoothness. Consequently, the stability of surface coated with the photosensitive layer can be maintained and an image can be pertinently formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming material. More specifically, it is an image-forming material by superposing a single color or multiple colors by utilizing the difference in adhesiveness between the exposed and unexposed areas of the photosensitive layer, and obtains a transfer similar to a print as a prepress proof for color proofing. And an image forming material that can be used

[0002]

2. Description of the Related Art Conventionally, it is known in the field of printing industry to use a prepress proof as a means for confirming the finish, color tone and the like of a finally printed printed matter before printing. This prepress proof has an overlay method and a surprint method, and is properly used depending on the image quality finally obtained and the purpose of use in plate making and printing processes. In the overlay method, a transparent base film is provided with a photosensitive layer containing a color material corresponding to a color separation mask, the film and the mask are brought into close contact with each other, exposed, and developed, and the respective films are superposed. And calibrate.

Unlike the overlay method, the surprint method has a high utility value because it can obtain a hard copy. For example, as disclosed in US Pat. Nos. 3060023, 3060024 and 3060025. In this method, a photopolymer photosensitive layer consisting of several layers is laminated on a single support to sequentially form color separation images. In addition, JP-A-59-97410,
There is also a prepress proof as described in JP-A-61-1885377, which can be used in both the overlay method and the surprint method. This method is used when you want to check simple characters etc. according to the purpose of use.
The versatility is great in that if you want to obtain a hard copy for checking a subtle color portion such as a picture by checking only with the valley, you can transfer this to the transfer target. However, there is a drawback that the working environment is deteriorated because a developing process using an organic solvent is required.

On the other hand, the inventors of the present invention formed a photosensitive layer containing a dye and / or a pigment on a transparent support, and exposed the image to give a tackiness in transferring exposed and unexposed areas of the photosensitive layer. The prepress pull obtained by transferring the image to the image receptor by cohesive failure of the photosensitive layer between the roll nips using an image forming material that transfers the image to the image receptor such as paper. Unlike conventional prepress proofs, there is no layer such as an adhesive layer between the material to be printed and the image forming material, so that the image and texture very similar to the actual printed matter can be reproduced. Has already found.

These image-forming materials are usually composed of a transparent support, a photosensitive layer containing a dye and / or a pigment, and a protective film. When the image forming material is used, the transparent support and the image surface of the mask original plate are brought into close contact with each other, and image exposure is performed from the mask side.
Then, the protective film is removed, and the photosensitive layer and the image receptor are transferred while applying heat and pressure between the nip rolls. However, since these image forming bodies are formed by forming a thinner photosensitive layer on a thin support and then laminating a protective film, holes are formed on the coated surface due to fine irregularities on the surface of the support or the protective film. It is easy to create so-called pinholes.

In order to form the photosensitive layer uniformly, it is preferable that the surface of the protective film is smoother so that the protrusion on the coated surface is less likely to occur. However, the protective film peels from the photosensitive layer during image formation, so that the protective film is protected. The film is required to have smoothness and peelability. As a film having smoothness and releasability, there is a silicone-treated polyester film, but since this film has too good releasability from the photosensitive layer, it easily peels off during storage, transfer and use of the image forming material. However, it did not function as a protective film. In addition, when a silicone-treated polyester film is used as a protective film, if air bubbles are caught in the photosensitive layer, the air bubbles may remain on the coated surface forever.

[0007]

Therefore, the present inventors have found that
As a result of diligent studies to solve the above problems, a polyolefin film having protrusions of a specific shape on the film surface has appropriate releasability and smoothness from the photosensitive layer, and is laminated with the photosensitive layer. In the case of doing so, it was found that the air bubbles entrapped did not remain forever, and the present invention was completed.

[0008]

According to the present invention, a photosensitive layer containing a colorant is formed on a support, and a protective film is further provided on the photosensitive layer. In the image-forming material that transfers an image to an image receptor such as paper due to the difference in adhesiveness between the exposed portion and the unexposed portion of the layer, the protective film is Z = -0.015W + H + 0.315 (W Is the maximum length of the protrusions present on the film surface, and H is the height of the protrusions.)
There is provided an image forming material characterized by being a polyolefin film having a smooth surface as described below.

By using the specific polyolefin film of the present invention as a protective film, it is possible to reduce the pinholes in the photosensitive layer and form a uniform photosensitive layer without uneven density.
It is possible to prevent a decrease in the density of the photosensitive layer and the density thereof. In addition, the specific polyolefin film of the present invention has sufficient unwinding and winding workability during coating with an actual coating machine, and the bubbles entrapped in the laminating step after coating will be processed on the next day. Disappears from the coated surface, so that an image forming material having no residual pattern of bubbles on the coated surface of the photosensitive layer can be obtained.

The polyolefin film used as the protective film has appropriate releasability and adhesiveness from the photosensitive layer and retains the laminated structure as an image forming material. The polyolefin film has protrusions on the surface of the film because a high molecular weight polyolefin resin remains in the film in a partially unmelted state when the film is formed. Most of the protrusions are called fish eyes, but it is not easy to eliminate fish eyes when forming a polyolefin film.

However, if the fish eye formed on the surface in contact with the photosensitive layer has such a shape that the value Z shown by the following discriminant is 0 or less, pinholes are not generated in the photosensitive layer. Significantly reduced. Z = -0.015W + H + 0.315 (W indicates the maximum length of the protrusions present on the film surface, and H indicates the height of the protrusions.) It is related to the height of the eye.

The polyolefin film used as the protective film preferably has a surface tension of 36 dyn / cm or less, more preferably 28 to 33 dyn / cm, on the surface in contact with the photosensitive layer. This is because when the protective film is peeled off before transferring the photosensitive layer to an image receptor such as paper, when the protective film surface in contact with the photosensitive layer surface does not have appropriate releasability, it is peeled off. This is because defects such as transfer of the photosensitive layer may occur in the protective film.

Examples of the polyolefin film include films such as polyethylene film and polypropylene film. The protective film may be composed of only one of these layers, but in order to maintain the stability of the photosensitive layer for a long period of time, the polyolefin film is a thin film with a thickness of 5 to 15μ, and a layer having gas barrier properties is provided on it. May be.
As a layer having a gas barrier property, a film such as a polyester film or polyvinyl alcohol (P
Examples thereof include polymer compounds such as VA) and ethylene vinyl alcohol (EvOH). If the protective film does not have an appropriate gas barrier property, the photopolymerization initiator and photosensitizer, which are the constituents of the photosensitive layer, migrate into the protective film, causing a decrease in image sensitivity, etc. Defects such as lowering may occur.

Further, for the purpose of ensuring the rigidity of the image forming material, the protective film may be lined with another material having high rigidity on the surface which does not come into direct contact with the photosensitive layer. As for rigidity, 1% tensile modulus is 1.5 kg / 15mm to 8.0kg / 15mm
Is the range. At this time, the material to be lined is not particularly limited, but a polyester film of about 50 to 100 μ can be used. When the rigidity of the image forming material is insufficient, the punch aptitude is reduced when using the punch system for alignment, the image forming material called a hem is lost during a series of operations such as exposure, and the workability is reduced. Etc., which affects the image quality and register accuracy of the finally obtained image.

As the support, transparent polyester having a thickness of 6 to 25 μm is used. The polyester is stable to heat, chemicals, light, etc., and yet fully transmits actinic rays,
Excellent thermal stability and dimensional stability. The support preferably has minute projections on its surface in order to prevent a so-called bamboo shoot-shaped winding failure during winding and unwinding. The maximum length of the protrusions on the surface of the support is 2 to 3.5 µ on average, and the number of protrusions in an area of 200 µ x 200 µ is preferably 130 or less, and more preferably 50 to 90. If the average of the maximum length is larger than 3.5 μ, it is larger than the film thickness of the photosensitive layer, so that the coated surface is likely to be defective, and if it is smaller than 2 μ and is too smooth, there is a possibility of winding failure. Also,
If the number of protrusions exceeds 130, even if the average maximum length of protrusions is within the above range, defects over time on the coated surface are likely to occur.

Further, since the support wound up in the form of a film is likely to be charged with static electricity, it is preferable to preliminarily contain a water-soluble antistatic agent in the polyester. As such an antistatic agent, a water-soluble surface active agent is preferable, and one which causes bleeding constantly on the film surface is preferably used. For example, alkyl sulfate, alkyl aryl sulfonate, alkyl phosphate, imidazoline, primary amine salt, quaternary ammonium salt, betaine, nonionic activator such as sorbitan-based, amide-based, alkylamine-based, ester-based , Ether type, etc. can be used. Specifically, alkyl imidazoline type amphoteric activator calcium salt, quaternary ammonium compound as Triton-K60 (manufactured by R & H), Catanac SN (AC
C.).

The photosensitive layer comprises a photopolymerizable compound, a thermoplastic or thermosetting resin, a coloring agent, etc., and is formed on the support.
Although it is provided with a thickness of 1.3 to 3.5 μ, a photopolymerization initiator, a thermal polymerization inhibitor, a resin plasticizer, a pigment dispersant, a silicone compound and the like may be used in combination as additives. As a colorant,
Conventionally used dyes and pigments such as organic pigments, dyes and carbon black can be used. It is also possible to mix several dyes and pigments in order to obtain the required hue. The pigment or dye added to the photosensitive layer should be 5 to 50% of the total solid content.
Weight% is suitable, and more preferably 9 to 20% by weight.

As the photopolymerizable compound, a monomer having an ethylenically unsaturated double bond, a prepolymer or the like can be used, but a compound capable of plasticizing a thermoplastic or thermosetting resin at room temperature is preferable. Typical compounds include 2-hydroxyethyl (meth) acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipenta. Examples thereof include erythritol hexaacrylate, and these photopolymerizable compounds may be used alone or in combination of two or more as required.

As the thermoplastic or thermosetting resin, a resin having excellent compatibility with the photopolymerizable compound can be used. For example, polyvinyl chloride, poly (meth) acrylic acid ester, epoxy resin, polyurethane resin, cellulose derivative (eg, ethyl cellulose, cellulose acetate, nitrocellulose), vinyl chloride-vinyl acetate copolymer, polyamide resin, polyvinyl acetal resin, diallyl. Examples thereof include phthalate resins and synthetic rubbers such as butadiene-acrylonitrile copolymer, and one or more of these resins are used depending on the required physical properties.

As the photopolymerization initiator, those which have little absorption in the visible light region and those which have good compatibility with the photopolymerizable compound are preferable, and examples thereof include benzophenone, benzoin ethyl ether, benzyl dimethyl ketal and azobisiso. Butyronitrile, 2-chlorothiozanzone, 2-methylthiozanzone, 2-ethylthiozanzone, 2-isopropylthiozanzone, 4'-isopropyl-2-hydroxy-2-
Methyl propiophenone and the like can be mentioned. In addition, a photosensitizer may be used in combination in order to increase the photopolymerization initiation efficiency. As the photosensitizer, an aromatic-aliphatic tertiary amine such as 4,4'-bisdiethylaminobenzophenone can be used. Since the photosensitizer may turn yellow, it is selected in consideration of acceleration efficiency, yellowing, compatibility with the initiator, energy of the actinic ray to be used, and wavelength range.

Further, a thermal polymerization inhibitor may be used in order to suppress radicals for photopolymerization. When using a thermal polymerization inhibitor, what is important is the amount added and compatibility, and the amount must be such that it does not interfere with the generation of radicals for photopolymerization and that the radicals are thermally suppressed. Generally, aromatic derivatives such as hydroquinone, p-methoxyphenol, t-butylcatechol, and pyrogallol are used, but compounds other than aromatic compounds may be used in combination.

In the photosensitive layer, if necessary, 0.01 to 30% by weight of a colorant is used as a solid content of a silicone compound having epoxy modified at both ends, a silicone compound having alcohol modified at both ends, and a silicone compound having a methacryloyl group. be able to. The silicone compound has good compatibility with the photopolymerizable compound and uniformly forms the coated surface of the photosensitive layer during coating. Further, although the above-mentioned silicone compound has a function of lowering the surface tension of the photosensitive layer, it has a strong affinity with the resin and does not transfer to a protective film with time even when stored at 40 ° C. Therefore, it has the feature of preventing blocking with time and blocking with heat. If the silicone compound is less than 0.01% by weight of the colorant,
You cannot prevent blocking. On the other hand, if it exceeds 30% by weight, there is a problem that the coated surface is repelled or the photosensitive layer of the next color cannot be formed.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. In the examples, “part” means “part by weight”. [Example 1] A dispersion liquid having the following composition was dispersed by a sand mill for 2 hours and then filtered through a 1-micron filter to prepare a coating liquid for a photosensitive layer. Diallyl isophthalate prepolymer (manufactured by Daiso) 11.40 parts Kayarad DPHA (manufactured by Nippon Kayaku Co., Ltd.) 7.10 parts Kayarad TPGDA (manufactured by Nippon Kayaku Co., Ltd.) 0.90 part Irgacure 907 (manufactured by Nippon Ciba Geigy) 1.20 parts Kayacure DETX-S (Nippon Kayaku Co., Ltd.) 0.60 parts Irgacure 369 (Nippon Ciba Geigy Co., Ltd.) 0.20 parts Solspers 24000 (ICI Japan Co., Ltd.) 0.10 parts X-22-169AS (Shin-Etsu Chemical Co., Ltd.) 0.20 parts MA -7 (manufactured by Mitsubishi Kasei) 2.50 parts R-54 (manufactured by Hoechst Japan) 0.30 part P-methoxyphenol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 0.20 part Methyl ethyl ketone 75.00 parts 12μ transparent support (polyethylene terephthalate film, quaternary grade) Ammonium compound with antistatic agent, 76 protrusions / 200μX200μ, average maximum protrusion length 3.28μ) ，
The photosensitive layer coating liquid is applied and dried to form a 2 μm photosensitive layer, and a protective film (maximum length of protrusions 150 μm,
Height 1μ, thickness 8μ polypropylene film and thickness 75
A polyester film of μ is laminated with an adhesive (Toyo Moton Co., Ltd.'s Adcote 329A / 329B = 1/1) is laminated with a laminator so that the polypropylene film side is in contact with the photosensitive layer. A forming material (black sheet) was obtained.

It was confirmed that small bubbles were scattered on the coated surface of the photosensitive layer immediately after being laminated with a laminator, but when left overnight, the scattered bubbles disappeared. Adhere the transparent support side of the image forming material and the silver salt side of the original positive mask with a UV printer (HMW-201KB manufactured by Oak Manufacturing Co., Ltd.)
An actinic ray of 50 mj / cm ² was applied. Next, the image forming material and the original positive mask were peeled off, the protective film was further peeled off, the coated paper (pearl coat manufactured by Mitsubishi Paper Mills Co., Ltd.) and the image forming material were adhered to each other, and the first laminator (Taisei Laminator 8B- 700 special type) pressure 4kg / cm ² , passing speed
When transferred at the nip between rollers under the conditions of 35 cm / min and roller surface temperature of 100 ° C, the photosensitive layer (thickness 2.0 μm) in the unexposed area was transferred, and the transferred material had the same texture as that of ordinary printed materials. I was able to get it. The image-forming material was stored in a thermostat at 25 ° C for 1 month, and the pinholes on the coated surface and the twist of the photosensitive layer were compared with those immediately after coating. There wasn't. The transferred image was the same as it was a month ago.

[Example 2] A coating solution for the yellow color photosensitive layer having the following composition was prepared in the same manner as in Example 1. Diallyl isophthalate prepolymer (manufactured by Daiso) 11.81 parts Kayarad DPHA (manufactured by Nippon Kayaku Co., Ltd.) 7.49 parts Kayarad TPGDA (manufactured by Nippon Kayaku Co., Ltd.) 0.78 parts Illukagua 907 (manufactured by Ciba-Gaigi Co.) 1.19 parts Kayacure DETX-S (Japan) Kayaku Co., Ltd.) 0.54 parts Irukagua 369 (Ciba-Gaigi Co., Ltd.) 0.04 parts Rionol Yellow FG1310 (Toyo Ink Mfg. Co., Ltd.) 3.12 parts X-22-169B (Shin-Etsu Chemical Co., Ltd.) 0.22 parts Methyl ethyl ketone 75.00 parts

3.12 parts of "Rionol Yellow FG1310" to 3.12 parts of "Rionol Blue FG7330" manufactured by Toyo Ink Mfg. Co., Ltd.
A cyan color photosensitive layer coating solution was prepared in the same manner as the yellow color photosensitive layer coating solution except that 0.22 parts of "X-22-169B" was replaced with 0.25 part of "KF-105" manufactured by Shin-Etsu Chemical Co., Ltd. It was adjusted.

3.12 parts of "Rionol Blue FG7330" manufactured by Toyo Ink Mfg. Co., Ltd. "Rionol Red Carmine 6B FG4200"
A magenta color photosensitive layer coating liquid was prepared in the same manner as the cyan color photosensitive layer coating liquid except that the amount was changed to 3.10 parts.

On the same transparent support as in Example 1, a photosensitive layer coating liquid was applied and dried to form a photosensitive layer of 2 μm,
Furthermore, a protective film (maximum length of protrusion 80μ, height 3.5μ,
The polypropylene film side is made of a polypropylene film with a thickness of 8μ and a polyester film with a thickness of 75μ laminated with an adhesive with a thickness of 5μ (adhesives 329A / 329B = 1/1 made by Toyo-Moton Co., Ltd.). The layers were laminated so as to be in contact with the layers to obtain image-forming materials (yellow sheet, cyan sheet and magenta sheet). When each image forming material was used and transferred to coated paper in the same manner as in Example 1 except that the roller surface temperature during transfer was changed to 90 ° C., the unexposed portion of the photosensitive layer (thickness 2.0 μm) was After transfer, we were able to obtain a transfer material that was completely the same in texture as ordinary printed materials.
Further, when the protective film was peeled off, blocking of the photosensitive layer on the protective film was not observed, and the peelability immediately after lamination was sufficiently retained even after 3 months.

In addition, the black photosensitive layer (black sheet) of Example 1
After the post-exposure to the transfer material, the yellow sheet, the magenta sheet, and the cyan sheet are sequentially transferred, and the image is formed by the post-exposure. No repelling of the image is observed even in the overlapping portion of each color, and a good transfer image is obtained. was gotten. Further, the image forming materials of each color were stored in a thermostat at 25 ° C for 1 month, and the pinholes on the coated surface and the photosensitive layer were compared with those immediately after coating. Was not than. Also, the transferred image was the same as it was a month ago.

Comparative Example 1 A protective film having a thickness of 80
µ high-density polyethylene film (maximum length of protrusion 80
An image forming material was obtained in the same manner as in Example 1 except that μ, height 3.5 μ, LUPIC LI manufactured by Tonensha Co., Ltd. was used. Immediately after the protective film was laminated with the laminator, small bubbles were observed on the coated surface of the photosensitive layer, but when left overnight, the scattered bubbles disappeared. Furthermore, when the image-forming material was stored in a thermostat at 25 ° C for one month, the number of pinholes on the coated surface increased remarkably, and the exposure sensitivity of the image decreased significantly.

[Example 3] As a protective film, a polypropylene film having a maximum projection length of 80 µ, a height of 0.3 µ, and a thickness of 15 µ and a polyester film having a thickness of 100 µ were used as an adhesive (ADCOAT 329A manufactured by Toyo Morton Co., Ltd.). An image-forming material was obtained in the same manner as in Example 1 except that the laminate of / 329B = 1/1) was used. Immediately after the protective film was laminated with the laminator, small bubbles were observed on the coated surface of the photosensitive layer, but when left overnight, the scattered bubbles disappeared.

Then, the obtained image-forming material was transferred to coated paper in the same manner as in Example 1. The unexposed portion of the photosensitive layer (thickness: 2.0 μ) was transferred to give a normal printed matter and texture. It was possible to obtain a transcript having no change. The image-forming material was stored in a thermostat at 25 ° C for 1 month, and the pinholes on the coated surface and the twist of the photosensitive layer were compared with those immediately after coating. There wasn't. The transferred image was the same as it was a month ago. Further, the obtained image-forming material was less likely to cause dents than the image-forming material of Example 1 and was easy to handle.

Example 4 As a protective film, a polypropylene film having a maximum length of 200 μ, a height of 1.0 μ, and a thickness of 60 μ and a polyester film having a thickness of 75 μ were used as an adhesive (Adcord 329A manufactured by Toyo Morton Co., Ltd.). An image-forming material was obtained in the same manner as in Example 1 except that the laminate of / 329B = 1/1) was used. Immediately after the protective film was laminated with the laminator, small bubbles were observed on the coated surface of the photosensitive layer, but when left overnight, the scattered bubbles disappeared.

Then, the obtained image-forming material was used to transfer onto a coated paper in the same manner as in Example 1. As a result, the photosensitive layer (thickness 2.0 μm) in the unexposed area was transferred, and the printed matter was It was possible to obtain a transcript having no change. The image-forming material was stored in a thermostat at 25 ° C for 1 month, and the pinholes on the coated surface and the twist of the photosensitive layer were compared with those immediately after coating. There wasn't. The image-forming material stored for a long time showed a decrease in image sensitivity, but when the exposure amount was increased, an image similar to the initial image was obtained. The obtained image-forming material was more likely to have dents than the image-forming material of Example 1.

[Embodiment 5] As a protective film, high density polyethylene (maximum length of protrusion 120 μ, height 0.8 μ) /
Adhesive / Ethylene vinyl alcohol copolymer / Adhesive /
25μ thick composite film consisting of 5 layers of high density polyethylene and 75μm thick polyethylene terephthalate
5μ adhesive (Advertisement 329A / 329B = manufactured by Toyo Morton)
An image forming material was obtained in the same manner as in Example 1 except that the multilayer film laminated in 1/1) was used. Immediately after the protective film was laminated with the laminator, small bubbles were observed on the coated surface of the photosensitive layer, but when left overnight, the scattered bubbles disappeared.

The image-forming material was stored in a thermostat at 30 ° C. for 1 month, and the pinholes on the coated surface and the twist of the photosensitive layer were compared with those immediately after coating. There was no. The transferred image was the same as it was a month ago. Compared with the image forming material of Example 4, the decrease in image exposure sensitivity was small, and the exposure sensitivity before storage with time was maintained even after 6 months.

Comparative Example 2 A protective film having a thickness of 60
μ low-density polyethylene film (maximum length of protrusion 100
An image forming material was obtained in the same manner as in Example 1 except that (μ, height 2.0 μ) was used. Due to the protrusion of the protective film, the coated surface of the photosensitive layer became uneven over time. Due to the change over time of the coated surface, uneven density occurred in some places during image formation. In addition, the handleability of the image forming material was poor, and the decrease in sensitivity over time was also significant.

Comparative Example 3 Example 1 was repeated except that a 75 μm-thick polyethylene terephthalate film, the surface of which was in contact with the photosensitive layer, was release-treated as the protective film.
An image forming material was obtained in the same manner as in. The air bubbles entrapped when the protective film was attached with a laminator remained on the coated surface of the photosensitive layer the next day, and the quality of the coated surface became poor. Also, this protective film had a weak adhesive force to the photosensitive layer and was easily peeled off, but the protective sheet was turned over even during a handling operation which did not require peeling.

[0039]

The image-forming material of the present invention uses, as a protective film, a polyolefin having an adequate releasability and smoothness from the photosensitive layer, and therefore maintains the stability of the coated surface of the photosensitive layer. However, the image can be formed well. Therefore, by using the image forming material of the present invention, it is possible to obtain a high-quality transfer material having the same material feeling as that of an ordinary printed material.

[0040]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a protrusion existing on a film surface.

FIG. 2 is a scatter diagram showing the relationship between the maximum length and height of protrusions present on the film surface and the presence or absence of minute density unevenness occurring in the photosensitive layer.

[Explanation of symbols]

 W: Maximum length of protrusions present on the film surface H: Height of protrusions present on the film surface *: Occurrence of minute density unevenness in the photosensitive layer ○: No occurrence of minute density unevenness in the photosensitive layer 1: Discriminant Z A straight line showing the relationship between W and H when = 0

Claims (1)

[Claims] 1. A photosensitive layer containing a colorant is formed on a support, and a protective film is further provided on the photosensitive layer. Imagewise exposure is performed to expose and unexposed areas of the photosensitive layer. In an image forming material that transfers an image to an image receptor such as paper due to the difference in adhesiveness during transfer, the protective film is Z = -0.015W + H + 0.315 (W is a protrusion present on the film surface. Is the maximum length, and H is the height of the protrusion.)
An image forming material comprising a polyolefin film having a smooth surface as described below.