Electric heating – Heating devices – Combined with diverse-type art device
Reexamination Certificate
2000-04-14
2002-01-29
Walberg, Teresa (Department: 3742)
Electric heating
Heating devices
Combined with diverse-type art device
C219S469000, C219S470000, C399S285000, C399S286000, C347S154000
Reexamination Certificate
active
06342689
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a heat developing method for heat developable image recording material and, more particularly, to a heat developing method for heat developable image recording material for photomechanical processes. More specifically, the present invention relates to a heat developing method for heat developable image recording material for scanners or image setters.
BACKGROUND OF THE INVENTION
As one of the light exposure methods of photographic photosensitive materials, there has been known an image forming method of so-called scanner type, in which an original image is scanned and which a silver halide photographic material is light-exposed based on the obtained image signals to form a negative or positive image corresponding to the image on the original image.
As for a case where an image output from a scanner on a film is further printed directly on a printing plate without any reversal step, or a scanner light source having a soft beam profile, a light-sensitive material for scanners exhibiting ultra-high contrast property has been desired.
A large number of photosensitive materials having a photosensitive layer on a support for forming images upon imagewise exposure have been known. Among them, as a system for rendering preservation of environments and image forming means simplified, a technology for forming images by heat development is exemplified.
In recent years, reduction of the amount of waste processing solutions is strongly demanded in the field of photomechanical processes from the standpoint of environmental protection and space savings. To cope with this, techniques are needed in relation to photosensitive heat developable materials for use in photomechanical processes, which can be effectively exposed by a laser scanner or laser image setter and can form clear black images having high resolution and sharpness. Such heat developable photosensitive materials can provide to customers a heat development processing system, without use of solution-type processing chemicals, simpler and free from incurring environmental destruction.
Methods for forming an image by heat development are described, for example, in specifications of U.S. Pat. Nos. 3,152,904 and 3,457,075 and D. Klosterboer, Imaging Processes and Materials, “Thermally Processed Silver Systems”, 8th ed., page 2, compiled by J. Sturge, V. Walworth and A. Shepp, Neblette (1969). The photosensitive material used contains a light-insensitive silver source (e.g., organic silver salt) capable of reduction, a photocatalyst (e.g., silver halide) in a catalytic activity amount, and a reducing agent for silver, which are usually dispersed in an organic binder matrix. This photosensitive material is stable at room temperature. However, when it is heated at a high temperature (e.g., 80° C. or higher) after the exposure, silver is produced through an oxidation-reduction reaction between the silver source (which functions as an oxidizing agent) capable of reduction and the reducing agent. The oxidation-reduction reaction is accelerated by the catalytic action of a latent image generated upon exposure. The silver produced by the reaction of the silver salt capable of reduction in the exposure region provides a black image and this presents a contrast to the non-exposure region. Thus, an image is formed.
Such heat developable photosensitive materials of this type have been known previously, but in most of those photosensitive materials, the photosensitive layer is formed by coating a coating liquid having a solvent of an organic solvent such as toluene, methyl ethyl ketone (MEK), methanol, and the like. Use of such. organic solvents as a solvent not only adversely affects human bodies during manufacturing processes but also is disadvantageous in term of costs due to recycling the solvents and others.
To cope with this, a method has been considered in which a photosensitive layer (hereinafter referred also to as “aqueous photosensitive layer”) is formed using a coating liquid of a water solvent not having the above problem. For example, Japanese Unexamined Patent Publication [KOKAI] (hereinafter referred simply to as “JP-A”) Showa Nos. 49-52,626 and 53-116,144, and the like set forth an example that gelatin is used as a binder. Also, JP-A-50-151,138 sets forth an example that a poly vinyl alcohol is used as a binder.
In JP-A-60-61747, an example that a gelatin and a polyvinyl alcohol are used together is described. In WO97/04,355, an example that a water soluble or water dispersion binder is used in the image forming layer and a water soluble binder such as gelatin, polyvinyl alcohol, cellulose derivatives, or the like is used in a protection layer is described. In addition, as another example other than the above examples, JP-A-58-28,737 sets forth an example of a photosensitive layer that a water-soluble polyvinyl acetal is used as a binder.
Such a binder surely allows to form the photosensitive layer in use of a coating liquid with a water solvent, thereby making such use advantageous in terms of environments and costs.
However, if the polymer such as gelatin, polyvinyl alcohol, water-soluble polyvinyl acetal, and so on is used as the binder, contractions due to dehydration as well as thermal expansions of the binder may occur at the same time and, because different from behavior of the support during thermal expansion, may cause the films to have wrinkles, thereby producing only unsuitable films for color printing in which the film is used in an overlapping manner.
In a meantime, apparatuses and methods for heat developing the heat developable recording material have been generally known, and for example, those are described in U.S. Pat. Nos. 3,629,549, 3,648,019, 3,709,472, and 4,518,845.
Svendsen's U.S. Pat. Nos. 3,629,549 and 4,518,845, both, disclose developing apparatuses having a drum coaxially attached in and thermally isolated from a heating member.
The sheet made of a film to be developed is engaged with the drum and is driven around the heating member. However, the heat developing apparatus of this type is not suitable for a film having relatively soft thermoplastic polymer binder in the outmost layer. That is, because the surface on a side supporting emulsion comes in contact with the isolation drum and the heating member, the outmost layer of the film may suffer from scratching scars or adhesive marks.
In another type of the heat developing apparatus, a heating drum is incorporated to be statically charged for holding a film during development. With such an apparatus, the outmost layer of the film on a side supporting the emulsion does not contact any structural member, and therefore, no scratching scar described above is made on the surface. However, the electrostatic apparatus used for holding the film on the drum during thermal development is relatively complicated and has a shape not suitable for heat developing a large size film.
Therefore, a technique has been desired to provide a heat developable photosensitive material having good resistance against scratching in use of the aqueous photosensitive layer having advantages in terms of environments and costs, which can be coated with good coating surface quality and may not suffer from beko and side ripples, and a heat developing method thereof.
It is an object of the invention to provide a heat developing method for heat developable image recording material for photomechanical processes, particularly, for scanners or image setters. More specifically, it is an object of the invention to provide a heat developing method for heat developable image recording material with good stability in size before and after heat development in preventing the surfaces of the heat developable image recording material from receiving scars of scratching and adhering during heat development. More particularly, it is yet another object of the invention to provide a heat developable image recording material and a heat developing method in which images can be obtained without processing unevenness but with stable heat d
Ishigaki Kunio
Naoi Takashi
Fuji Photo Film Co. , Ltd.
Fuqua Shawntina T
Walberg Teresa
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