The present invention relates to a pressurizing image forming apparatus which makes use of a photo- and pressure-sensitive heat-developable material having a substrate and a layer formed on the substrate from a substance which is photosensitive and developable by application of heat and capable of fixing the developed image by application of pressure. More particularly, the present invention is concerned with a pressurizing image forming apparatus which fixes, by application of pressure, an image which has been formed on the heat-developable material of the type mentioned above through exposure and developed by application of heat.
An image recording material employing microcapsules containing a photosensitive composition has been known. An example of such a recording material is disclosed in Japanese Patent Laid-open No. 179,836/1982. This recording material has a substrate which carries capsules made of a synthetic polymeric resin and containing a vinyl compound, a photopolymerization initiator and a coloring precursor.
In recording an image using this recording material, the material is first exposed so that the microcapsules are hardened in conformity with the form of the image. Then, as the recording material is pressed, the microcapsules which have not been hardened are ruptured so as to release the coloring agent precursor, thus forming a color image. This image recording system provides a high quality of the recorded image with a dry-type simple processing, but suffers from a disadvantage in that the photosensitivity is much smaller as compared with the system which makes use of silver halide.
Under this circumstance, the present applicant has proposed, in the specification of Japanese Patent Laid-open No. 275742/1986, a novel recording material which has a high photosensitivity and which ensures a high quality of the recorded image with a simple dry-type process. This recording material is a photo- and pressure-sensitive heat-developable material constituted by a carrier and a layer formed on the surface of the carrier, the layer containing at least a photosensitive silver halide, reducing agent, polymerizable compound and a color image forming substance, wherein the polymerizable compound and the color image forming substance are confined in common microcapsules.
An image recording method which makes use of this photo- and pressure-sensitive heat-developable material is disclosed in the specification of Japanese Patent Laid-open No. 278849/1986 filed by the same applicant. According to this method, the heat-developable material is first exposed so that a latent image is formed thereon in conformity with the image to be recorded. Then, the material is heated for development so that the polymerizable compound in the area where the latent image exists is polymerized to produce a polymeric compound, thus thermally setting the microcapsules. Then, the material is superposed on an image receiving material having an image receiving layer capable of receiving the color image forming substance, and is pressed to the image receiving material so that at least part of the microcapsules having no latent image is ruptured so as to transfer the color image forming substance to the image receiving material, thereby forming an image on the latter.
In order to obtain a clear image by the transfer of the heat-developed image from the photo- and pressure-sensitive heat-developable material to the image receiving material, it is essential that the heat-developable material be pressed uniformly onto the image receiving material under a given condition.