Image forming method and mono-sheet laminate

Abstract

Provided are an image forming method and a mono-sheet laminate for forming a discharge image in which the reproducibility of discharge behavior is high and the occurrence of processing defects due to dust adhesion or the like is suppressed. The image forming method involves using a mono-sheet laminate (10) obtained by integrating a transparent supporting body (1) on which an image receiving element (2) and an auto-positive silver halide photographic photosensitive element (3) are laminated, a cover sheet (4) covering the photosensitive element (3), a conductive connecting member (6) for grounding which is connected to a peripheral part of a surface of the transparent supporting body (1), the surface being on the reverse side to the surface on which the image receiving element (2) is laminated, and a pod containing an alkaline processing liquid and forming an image on the mono-sheet laminate (10). The image forming method involves performing discharge on the mono-sheet laminate (10) from an electrode (32a) of a DC discharge device (30) disposed at a distance of 0-15 mm from a surface of the cover sheet (4) in the normal direction of the surface, and developing the alkaline processing liquid contained in the pod between the photosensitive element (3) and the cover sheet (4) to form a discharge image.

Description

Image forming method and mono-sheet laminate

[0001] The present invention relates to an image forming method and a mono-sheet laminate, and more particularly to an image forming method in which an autopositive type silver halide photographic light-sensitive element is exposed by discharge to form a discharge image, and a mono-sheet laminate exposed by the image forming method.

[0002] Kirlian photography is a method for recording electrostatic discharges on silver halide photographic materials. This method involves applying an AC voltage of approximately 10,000 volts at a frequency of 1 to 20 kHz and recording the corona discharge from the subject. This method, known as Kirlian photography, requires a large-scale device to generate high AC voltage, which is generally difficult to prepare. Furthermore, it is difficult to control the discharge state, resulting in insufficient stability of the discharge behavior.

[0003] In contrast to this, an attempt to record an electrostatic discharge image on a silver halide photographic light-sensitive material using a simpler device has been reported in which a voltage of 3,000 to 10,000 volts is applied to electrodes or a subject using a DC circuit with a capacitor, and the image is recorded on black-and-white film, color reversal film, or the like (Non-Patent Document 1).

[0004] In these methods, the electrodes come into contact with the photosensitive material either directly or through the air, which can damage the photosensitive material or cause foreign matter such as dust to adhere to it due to charging, which can affect the subsequent development process and can easily cause processing defects other than those directly caused by the electrical and optical effects of discharge.

[0005] Furthermore, the strength of electrostatic discharges that cause dielectric breakdown is easily affected by the temperature and humidity of the area where the discharge occurs and the condition of the surface on which the discharge occurs, and it was not easy to prepare a silver halide photographic material with the appropriate sensitivity and gradation for recording discharge images. Furthermore, discharges occur in various modes, and in cases where there is a large difference in intensity between very strong and weak areas, it has not been possible to simultaneously record the discharge behavior in a single photograph.

[0006] Studies on the High-Voltage Electric Discharge Photography Journal of the Photographic Society of Japan, 1983, Vol. 46, No. 6, pp. 463-469

[0007] One embodiment of the technology of the present disclosure provides an image forming method for forming a discharge image in which the discharge behavior is highly reproducible and the occurrence of processing defects due to dust adhesion and the like is suppressed, and a mono-sheet laminate exposed to discharge by the image forming method.

[0008] The invention according to a first aspect is an image forming method for forming an image on a mono-sheet laminate, the mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding joined to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, in which discharge is applied to the mono-sheet laminate from an electrode of a direct current discharge device arranged at a distance of 0 mm to 15 mm from the surface of the cover sheet in the normal direction to the surface, and the alkaline processing liquid contained in the pod is spread between the silver halide photographic light-sensitive element and the cover sheet to form a discharge image.

[0009] The invention according to a second aspect is an image forming method for forming an image on a mono-sheet laminate, the mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding joined to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, the image forming method comprising the steps of: discharging a first conductive material from the surface of the cover sheet at a distance of 0 mm to 10 mm in a direction normal to the surface; discharging from an electrode of a DC discharge device to the first conductive material; and spreading the alkaline processing liquid contained in the pod between the silver halide photographic light-sensitive element and the cover sheet to form a discharge image.

[0010] The invention according to a third aspect is an image forming method for forming an image on a mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding joined to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, the image forming method comprising the steps of: placing a sheet-like insulating material at a distance of 0 mm to 15 mm from the surface of the cover sheet in a direction normal to the surface; subjecting the sheet-like insulating material to corona discharge from an electrode of a DC discharge device to electrostatically charge the sheet-like insulating material; causing a dielectric breakdown at at least one point on the statically charged sheet-like insulating material; discharging the charged static electricity; and spreading the alkaline processing liquid contained in the pod between the silver halide photographic light-sensitive element and the cover sheet to form a discharge image.

[0011] In the image forming method according to a fourth aspect of the present invention, in the third aspect, it is preferable that the sheet-like insulating material has a void penetrating through at least a portion of the sheet-like insulating material in the thickness direction, and that dielectric breakdown is caused by bringing an electrode of a DC discharge device close to the void.

[0012] In the image forming method according to the fifth aspect of the present invention, in the third or fourth aspect, it is preferable that the sheet-like insulating material has a second conductive material disposed at at least one point on the surface of the sheet-like insulating material, and that dielectric breakdown occurs by discharging from an electrode of a DC discharge device to the second conductive material.

[0013] In the image forming method according to the sixth aspect of the present invention, in the third aspect, it is preferable that the sheet-like insulating material is placed at a distance of 1 mm to 15 mm from the surface of the cover sheet in the direction normal to the surface, and the distance between the charged sheet-like insulating material and the mono-sheet laminate is partially shortened, causing dielectric breakdown at at least one point on the sheet-like insulating material.

[0014] In the image forming method according to the seventh aspect of the present invention, in any one of the third to sixth aspects, the sheet-like insulating material preferably absorbs at least a part of light having a wavelength in the photosensitive region of the silver halide photographic light-sensitive element.

[0015] In the image forming method according to the eighth aspect of the present invention, in any one of the third to seventh aspects, the sheet-like insulating material preferably does not transmit light having wavelengths in the photosensitive region of the silver halide photographic light-sensitive element.

[0016] In the image forming method according to a ninth aspect of the present invention, in any one of the third to eighth aspects, the sheet-like insulating material preferably does not transmit light of wavelengths in the photosensitive region of the silver halide photographic light-sensitive element and shields the exposed surface of the silver halide photographic light-sensitive element from light.

[0017] The invention according to a tenth aspect is an image forming method for forming an image on a mono-sheet laminate, the method comprising: a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated; a cover sheet covering the silver halide photographic light-sensitive element; a conductive connecting member for grounding bonded to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated; and a pod containing an alkaline processing liquid, the method comprising: placing a sheet-like insulating material that blocks at least a part of wavelengths in the visible light region on the upper side of the cover sheet; This image forming method comprises placing a nearby third conductive material on the inner surface of a sheet-like insulating material facing the cover sheet, providing a conductive portion that is electrically conductive with the third conductive material, with a portion of the conductive portion exposed on the outer surface of the sheet-like insulating material, bringing an electrode of a DC discharge device into contact with or close to a portion of the exposed conductive portion, discharging from the electrode through the conductive portion to the third conductive material, and spreading an alkaline processing liquid contained in a pod between the silver halide photographic light-sensitive element and the cover sheet, thereby forming a discharge image including an image showing the shape of the third conductive material.

[0018] In the image forming method according to the eleventh aspect of the present invention, in the tenth aspect, it is preferable that the conductive portion electrically conducting with the third conductive material is integrated with the third conductive material, penetrates the sheet-like insulating material, and is exposed on the outer surface side of the sheet-like insulating material.

[0019] In the image forming method according to the twelfth aspect of the present invention, in the tenth aspect, it is preferable that the conductive portion electrically conducting with the third conductive material is a member that is detachable from the third conductive material, and that a portion of the conductive portion is exposed on the outer surface of the sheet-like insulating material when attached to the third conductive material.

[0020] In the image forming method according to the thirteenth aspect of the present invention, in any one of the tenth to twelfth aspects, the sheet-like insulating material preferably covers the entire exposed surface of the silver halide photographic light-sensitive element.

[0021] In the image forming method according to a fourteenth aspect of the present invention, in any of the tenth to thirteenth aspects, it is preferable that the sheet-like insulating material does not transmit at least a portion of wavelengths in the visible light region, and that, under light of a wavelength in the visible light region that is not transmitted, an electrode of a DC discharge device is brought into contact with or close to the conductive portion of the third conductive material, and discharge is caused from the electrode to the third conductive material via the conductive portion.

[0022] In the image forming method according to the fifteenth aspect of the present invention, in any one of the first to fourteenth aspects, an element that changes the absorption, scattering or reflection of light is preferably provided above the cover sheet.

[0023] In the image forming method according to the sixteenth aspect of the present invention, in any one of the first to fifteenth aspects, it is preferable that the discharge image is formed with a color density corresponding to the exposure intensity of the positive and negative areas of the silver halide photographic light-sensitive element.

[0024] The image forming method according to a seventeenth aspect of the present invention is preferably the image forming method according to any one of the first to sixteenth aspects, further comprising a step of exposing to visible light in addition to the exposure by discharge.

[0025] An eighteenth aspect of the invention is a mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding joined to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, wherein the mono-sheet laminate has been subjected to at least one exposure by discharge by the image forming method of any one of the first to sixteenth aspects, but has not been subjected to development processing with the alkaline processing liquid contained in the pod.

[0026] The mono-sheet laminate according to the nineteenth aspect of the present invention is preferably the mono-sheet laminate according to the eighteenth aspect, which is set in a camera or a printer, and is exposed to light in a direct positive area at least once by the camera or the printer, followed by development processing.

[0027] A twentieth aspect of the invention is a mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding joined to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, wherein the mono-sheet laminate has been subjected to at least one exposure by discharge and at least one exposure by visible light by the image forming method of any one of the first to sixteenth aspects, but has not been subjected to development processing with the alkaline processing liquid contained in the pod.

[0028] In the mono-sheet laminate according to a twenty-first aspect of the present invention, in the twentieth aspect, it is preferable that the mono-sheet laminate is set in a camera or a printer, and development processing is carried out without exposure by the camera or the printer.

[0029] FIG. 1 is a plan view showing an embodiment of a mono-sheet laminate according to the present invention. FIG. 2 is a cross-sectional view of the mono-sheet laminate taken along line 2-2 in FIG. 1. FIG. 3 is a conceptual diagram showing an example of a characteristic curve showing the relationship between exposure illuminance and color density of an autopositive silver halide photographic light-sensitive element. FIG. 4 is a diagram showing a first embodiment of an image forming method according to the present invention. FIG. 5 is a diagram showing a second embodiment of an image forming method according to the present invention. FIG. 6 is a diagram showing a third embodiment of an image forming method according to the present invention. FIG. 7 is a diagram showing a fourth embodiment of an image forming method according to the present invention.

[0030] Hereinafter, preferred embodiments of the image forming method and mono-sheet laminate according to the present invention will be described with reference to the accompanying drawings.

[0031] Furthermore, although the following description corresponds to a representative embodiment of the present invention, the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits.

[0032] [Mono-sheet laminate] FIG. 1 is a plan view showing an embodiment of a mono-sheet laminate according to the present invention.

[0033] The mono-sheet laminate 10 shown in FIG. 1 is, for example, a self-developing instant film, and has a rectangular card shape.

[0034] The mono-sheet laminate 10 shown in FIG. 1 is integrally formed with an exposure section 12, a pod 14 containing an alkaline processing liquid 14a, and a trap section 16 having an absorbent material 16a.

[0035] The overall size of the mono-sheet laminate 10 is 54 mm x 86 mm, and the size of the image surface 10a for observation is 46 mm x 62 mm.

[0036] FIG. 2 is a cross-sectional view of the mono-sheet laminate taken along line 2-2 of FIG.

[0037] The mono-sheet laminate 10 shown in Figure 2 is a substrate in which an image-receiving element 2 and an autopositive type silver halide photographic light-sensitive element 3 (hereinafter sometimes abbreviated as "light-sensitive element 3") are laminated on the same transparent support 1, and a cover sheet 4 is adhered to the substrate by spacers 5 with adhesive at the frame portions on three sides of the final formed image.

[0038] The pod 14 shown in FIG. 1 is a container (processing element) that contains an alkaline processing liquid and can be burst by pressure, and is joined to one side of the substrate and the cover sheet 4, leaving a gap between them, to form the mono-sheet laminate 10.

[0039] After the photosensitive element 3 is exposed through the cover sheet 4, the pod 14 is pressure-ruptured by the opposing rollers, and an alkaline processing solution is spread from the pod 14 onto the surface of the photosensitive element in the gaps between the mono-sheet laminate 10, thereby carrying out development processing and forming an image. Any excess alkaline processing solution spread is captured by the absorbent material 16a in the trap section 16.

[0040] In this embodiment, the processing solution is spread to a thickness of about 40 to 80 μm, but the spreading process of the processing solution is easily affected by the surface condition of the photographic element. That is, during electrostatic discharge, as described below, damage to the surface of the photosensitive material and the adsorption of foreign matter due to static electricity can easily cause fluctuations in the spread thickness of the processing solution, leading to uneven color density and repelling. In this embodiment, by forming the mono-sheet laminate 10 in advance using the cover sheet 4 before discharge, damage to the surface of the photosensitive element 3 is minimized, and spreading of the processing solution to a thickness of 80 μm or less can be carried out without any problems.

[0041] From the viewpoint of suppressing unevenness in color density, the cover sheet 4 is preferably at least 20 μm thick, and more preferably 40 to 150 μm thick. The cover sheet 4 is made of, for example, polyethylene terephthalate (PET), a type of plastic, but is not limited to PET and may be made of any transparent material that does not allow water to pass through.

[0042] <Use of Auto-Positive Emulsion> The photosensitive element 3 of this embodiment uses an auto-positive silver halide emulsion and utilizes not only the relatively low illumination range of the positive exposure area but also the fairly high illumination range of the re-reversal negative exposure area, thereby enabling recording of electrostatic discharge light with a dynamic range more than twice that of conventional methods. This will be described in detail below.

[0043] The intensity of the discharge light ranges from a level that can barely be seen with the naked eye in a dark room to a level where a strong light can be seen. If the light intensity is too strong, the sense of the eye is saturated, and even if there are several strong streaks of light, the detailed behavior of each individual discharge may not be discernible.

[0044] When the illuminance of an auto-positive emulsion-based photographic material is increased from an unexposed state, it shows a positive-tone response in areas with low illuminance, and the formed image density decreases with the amount of light. After that, by further increasing the illuminance, it shows an inverted negative-tone response, and the image density increases with the light illuminance. This region is sometimes called the re-reversed negative region.

[0045] By utilizing this property of autopositive silver halide emulsion systems, it is possible to record the light of an electrostatic discharge in the relatively low illumination range of the positive exposure area, as well as in the fairly high illumination range of the re-reversal negative exposure area.

[0046] This method will be explained in more detail below.

[0047] A typical color photographic light-sensitive material is composed of three layers in the visible light region: a blue-sensitive emulsion layer (BL), a green-sensitive emulsion layer (GL), and a red-sensitive emulsion layer (RL), and each of these emulsion layers is combined with a yellow dye image-forming compound, a magenta dye image-forming compound, and a cyan dye image-forming compound. In the case of a positive-type photographic material, the sensitivity balance of the three layers is basically determined to match human vision in the illuminance region of positive exposure.

[0048] The high-illuminance re-reversal negative area is not normally used in photography. To avoid the possibility of accidentally reflecting flash light directly off a mirror during photography, the sensitivity of the three photosensitive layers is designed to be approximately equal to prevent the reflected light from having a noticeable color. In this example, intentionally shifting the sensitivity balance of the three photosensitive layers allows changes in light intensity in the high-illuminance area to be recorded as changes in the color of the color image. For example, if the negative sensitivity balance of the three photosensitive layers is consistent, the color image of the negative image changes from white to gray to black as the illuminance increases. If the negative sensitivity of the BL and GL layers is intentionally increased, the color image of the negative image changes from white to red to black as the illuminance increases.

[0049] FIG. 3 is a conceptual diagram showing an example of a characteristic curve showing the relationship between exposure illuminance and color density of an autopositive type silver halide photographic light-sensitive element.

[0050] The negative sensitivity of the three photosensitive layers is designed with consideration given to reducing the occurrence of unintended re-reversal accidents in high-illuminance areas during positive-type photography. The illuminance (E) margin in the white area can be set to approximately 1 to 3 Log E, and the sensitivity difference between the three photosensitive layers can be set to approximately 0 to 1.5. In this case, to intentionally increase the discrimination of light intensity at high illuminance, it is preferable to lower the exposure margin and increase the sensitivity difference between the three photosensitive layers. From the perspective of discrimination, it is particularly preferable to design the re-reversal negative sensitivity balance so that it differs from the visually perceived color image change in the positive area at low illuminance. In low-illuminance positive images, electrostatic images are generally recorded as dye images in the order black-blue-blue-white. To distinguish from this, it is preferable to design a negative image in the order of, for example, white-yellow-green-black, white-yellow-red-black, white-magenta-red-black, white-magenta-blue-black, white-cyan-green-black, etc. The sensitivity design of the negative image can be controlled by the core-shell structure of the silver halide emulsion grains described below, the type of metal complex to be doped, etc.

[0051] On the other hand, the relative sensitivity of the three emulsion layers to ultraviolet light may be changed, for example, by adjusting the amount and location of an ultraviolet absorber contained in the light-sensitive element.

[0052] Reducing the amount of UV absorber used on the light source side of the photosensitive layer increases the amount of UV light reaching the photosensitive layer, making it possible to detect discharge light at lower illuminance levels. A typical autopositive silver halide photographic light-sensitive element is composed of BL, GL, and RL layers, in that order from the exposure light source side. To independently control the sensitivity of the three light-sensitive layers, reduce the amount of UV absorber on the light source side of the layer you want to increase the sensitivity of. For example, if a certain amount of UV absorber is added to a light-sensitive element, if the layer to which it is added is closer to the exposure light source than the BL, all three layers (BL, GL, and RL) will be desensitized; if it is added between the GL and RL layers, only the RL layer will be desensitized. This effect is effective in both positive and negative regions.

[0053] The image receiving element 2, the photosensitive element 3, the processing element (pod 14), and the like that constitute the mono-sheet laminate 10 will be described in detail later.

[0054] <Discharge Exposure> The image forming method according to the present invention is a method for recording (forming) an image of discharge on the photosensitive element 3 by a discharge caused by breakdown of insulation between charged bodies on the exposed side (cover sheet 4 side) of the photosensitive element 3. The discharge generates light that is primarily in the ultraviolet region but also in the visible light region. It is not entirely clear whether the influence of this discharge on the formation of a latent image in the silver halide emulsion is due solely to the contribution of light or whether the electric field near the discharged area also has an effect, but it is believed that light contributes significantly. In the present invention, the combination of both contributions is referred to as exposure by discharge. The image displayed by the photosensitive material upon exposure by this discharge is referred to as a "discharge image."

[0055] In the present invention, discharge can be carried out in air at a temperature range of 0 to 30° C. and a relative humidity range of about 20 to 60% at atmospheric pressure. However, discharge can also be carried out under conditions other than these by intentionally changing the temperature, humidity, or pressure, or by adjusting the partial pressure of oxygen or the partial pressure of a specific gas component.

[0056] [First Embodiment of Image Forming Method] FIG. 4 is a diagram showing a first embodiment of an image forming method according to the present invention.

[0057] As shown in FIG. 4, in the present invention, it is preferable to discharge the mono-sheet laminate 10 using a DC discharge device 30.

[0058] <DC Discharge Device> Examples of the DC discharge device 30 include a Van de Graaff generator, a DC circuit using a capacitor, and an ion gun.

[0059] A Van de Graaff generator is a device that creates an extremely high potential difference by transporting the electric charge generated by the separation between two types of rollers installed above and below the belt that are driven by the belt and storing it in a hollow metal sphere installed on an insulating cylinder.

[0060] A typical example of a Van de Graaff generator is one that stores a (+) charge using a combination of acrylic resin rollers, rubber belts, and vinyl chloride resin rollers. It is also possible to store a (-) charge using a combination of rollers and belts. Even a small device with a hollow metal sphere with a diameter of about 20 cm can create a potential difference of about 50 kV, and when the tip of a metal rod conducts electricity from there to a spherical electrode and discharges to a grounded metal, a spark discharge that is clearly visible to the naked eye can be observed even in a brightly lit room.

[0061] The DC discharge device 30 may be one provided for evaluating fire resistance caused by static electricity or resistance of electronic components.

[0062] A voltage of 3 kV to 300 kV is easy to handle, more preferably 6 kV to 100 kV, and even more preferably 6 kV to 50 kV.

[0063] By setting the voltage within this range, it is easy to record a visually recognizable discharge as a discharge image when actually discharging in a slightly dark room. Furthermore, this is preferable because the mono-sheet laminate 10 is not damaged by the shock of the discharge. If the voltage is too low, it is difficult to record the discharge as an image, and if it is too high, the discharge light is too intense, and many parts of the discharge image are likely to be blurred.

[0064] Next, the electrodes of the DC discharge device 30 will be described.

[0065] The shape of the discharge electrode is not particularly limited, but from the viewpoint of handling, a rod-shaped discharge electrode 32 is preferable.

[0066] The tip 32a of the discharge electrode rod 32 may be shaped like the tip of a cylindrical rod, or may be machined. To increase the voltage required for discharge, it is effective to reduce the curvature of the tip, and the tip of the electrode 32a may be spherical rather than cylindrical in cross section. This voltage can be increased by increasing the radius of the sphere.

[0067] The size of the cylinder of the discharge electrode rod 32 is preferably 2.0 to 8.0 mm in diameter, more preferably 3.0 to 5.0 mm.

[0068] When the tip electrode 32a is spherical, its diameter is preferably 3.0 to 10.0 mm, more preferably 4.0 to 7.0 mm. The shape of the tip of the electrode can be set arbitrarily depending on the atmosphere in which the discharge occurs and the peripheral member configuration of the mono-sheet laminate 10 used.

[0069] The distance D1 between the electrode 32a and the cover sheet 4 during discharge (the distance from the surface of the cover sheet 4 to the electrode 32a in the normal direction to the surface) can be controlled by the voltage, the approach speed to the cover sheet 4, etc. This distance D1 is preferably 0 mm or more and 15 mm or less, more preferably 0 mm or more and 10 mm or less, even more preferably 0 mm or more and 8 mm or less, and particularly preferably 0.05 mm or more and 5 mm or less.

[0070] If this distance D1 is large, the light emitted during discharge will diffuse widely before reaching the surface of the photosensitive element 3, and the discharge image will likely become very blurred. Here, the distance in the normal direction refers to the shortest distance between the surface of the cover sheet 4 and the electrode 32a during discharge. The preferred range of voltage is 3 kV to 300 kV, more preferably 6 kV to 100 kV, and most preferably 6 kV to 50 kV.

[0071] The number of discharges may be one or more. If the number of discharges is too many, the entire photosensitive element will be exposed to the discharge light, resulting in a blurred image. Therefore, the number of discharges can be adjusted appropriately to obtain a desired discharge image.

[0072] <Discharge Mode> In the first embodiment of the image forming method according to the present invention, one preferred mode of discharge from the DC discharge device 30 is spark discharge. It is preferable that the discharge be carried out in air at a voltage of approximately 6 kV to 100 kV, more preferably approximately 6 kV to 30 kV. Spark discharge emits light that is primarily ultraviolet light, but also contains light components in the short wavelength component of visible light. Many of these emit light with an intensity that can be visually confirmed.

[0073] If the voltage is too high, the shock caused by the discharge will be large, and there is a risk that the joints of the mono-sheet laminate 10 will be destroyed or damaged.

[0074] Another mode that can be used as the discharge form from the DC discharge device 30 in the present invention is corona discharge. This is discharge from an electrode with a large curvature at the tip, and is accompanied by ionization of the atmosphere. Corona discharge has a weak luminous intensity, and can only be confirmed visually in a dark room without external light.

[0075] In the case of a photosensitive material with an ISO sensitivity of about 800, the level is such that it will be exposed to light if exposed to light for several seconds or more on the surface of the photosensitive element 3 .

[0076] <Conductive Material for Grounding> In the image forming method of the present invention, it is preferred that the substrate including the photosensitive element 3 is grounded.

[0077] That is, it is preferable that the surface of the mono-sheet laminate 10 opposite to the surface to be exposed (the surface on the cover sheet 4 side) is grounded.

[0078] In the first embodiment shown in Figure 4, a conductive connecting member 6 for grounding is connected to the peripheral portion of the surface of the transparent support 1 opposite to the surface on which the image-receiving element 2 is laminated, and the mono-sheet laminate 10 is placed on an aluminum plate 20 that is grounded via the conductive connecting member 6.

[0079] Although a metal plate or metal wire may be directly grounded, it is also preferable to use a metal-evaporated tape for the conductive connecting member 6 due to the flexibility of the main body and ease of processing. Aluminum-evaporated tape is preferred because it is inexpensive and has excellent conductivity. Grounding from the opposite side of the exposed surface makes it easier for discharge to occur stably. To prevent the direction of discharge exposure from being biased within the exposed surface, it is preferable to ground uniformly across the entire frame of the final image.

[0080] In order to increase the probability of discharge occurring in a specific direction, it is also preferable to limit the direction of the earth on the surface opposite to the exposed surface.

[0081] In the image forming method of the first embodiment, an electrode 32a of a DC discharge device 30 is disposed at a distance D1 of 0 mm to 15 mm from the surface of the cover sheet 4 of the mono-sheet laminate 10 in the normal direction to the surface of the mono-sheet laminate 10, and discharges (spark discharges) the discharge electrode 32a to the mono-sheet laminate 10. The polarity of the discharge electrode 32a is set to be positive.

[0082] A latent discharge image is formed on the photosensitive element 3 by the above-mentioned spark discharge.

[0083] <Discharge Treatment> Discharge treatment is preferably performed on the discharged mono-sheet laminate 10 before additional positive image exposure or before spreading with an alkaline processing solution. Examples of devices for performing the discharge treatment include a self-discharge static eliminator and an electrical static eliminator. A self-discharge static eliminator is made of an array of thin conductive fibers, and when grounded and brought close to a charged body, corona discharge occurs, thereby removing the charge from the charged body. Examples of electrical static eliminators include AC static eliminators, DC static eliminators, and blower static eliminators. Discharge treatment not only reduces problems such as poor transport and foreign matter adhesion during exposure and processing, but also prevents electrical malfunctions in the exposure processing device.

[0084] <Installation of an Element That Changes Light Absorption, Scattering, or Reflection> In the present invention, an element that changes light absorption, scattering, or reflection may be installed on the cover sheet 4 (on the static electricity generating surface). Installing an element that changes light absorption, scattering, or reflection can specifically change the color or direction of light emitted by electrostatic discharge, thereby forming an image with a highly aesthetic design. There are no particular restrictions on the material or shape of such an element, and any desired one can be used.

[0085] <Autopositive Silver Halide Photosensitive Element> The autopositive silver halide photographic light-sensitive element 3 constituting the mono-sheet laminate 10 is an autopositive silver halide photographic light-sensitive element comprising pre-uncovered internal latent image-type silver halide grains on a transparent support 1, and exhibits a positive photographic response in a specific exposure range.

[0086] The internal latent image type direct positive silver halide emulsion of the present invention (hereinafter sometimes abbreviated as "internal latent image type silver halide emulsion") is a silver halide emulsion which, when imagewise exposed, forms a latent image mainly inside the silver halide grains. Specifically, it is preferred that the silver halide emulsion is coated in a certain amount on a transparent support 1, exposed for a fixed time of 0.01 to 1 second, and developed in Developer A ("internal type" developer) described below at 20°C for 5 minutes, and the maximum density obtained is at least 5 times the maximum density obtained when a second sample exposed in the same manner as above is developed in Developer B ("surface type" developer) described below at 20°C for 5 minutes. The maximum density here is measured by a conventional photographic densitometry method.

[0087] <Developer A> 2g N-methyl-p-aminophenol sulfite, 90g sodium sulfite (anhydrous), 8g hydroquinone, 52.5g sodium carbonate (monohydrate), 5g potassium bromide, 0.5g potassium iodide. Add water to make 1 liter. <Developer B> 2.5g N-methyl-p-aminophenol sulfite, 10g L-ascorbic acid, 35g potassium metanitrate, 1g potassium bromide. Add water to make 1 liter.

[0088] To obtain a direct positive image, the above-mentioned internal latent image type silver halide emulsion is imagewise exposed, and then a uniform second exposure is given to the front surface of the exposed layer before or during development ("light fogging method", e.g., British Patent No. 1,151,363), or development is carried out in the presence of a nucleating agent ("chemical fogging method", e.g., Research Disclosure, Vol. 151, No. 15162, pp. 76-78). In the present invention, a method for obtaining a direct positive image by the "chemical fogging method" is preferred.

[0089] Examples of the nucleating agent include hydrazines described in U.S. Patent Nos. 2,563,785 and 2,588,982, hydrazides and hydrazones described in U.S. Patent No. 3,227,552, heterocyclic quaternary salt compounds described in British Patent No. 1,283,835, JP-A-52-69613, JP-A-55-138742, JP-A-60-11837, JP-A-62-210451, JP-A-62-291637, U.S. Patent Nos. 3,615,515, 3,719,494, 3,734,738, 4,094,683, 4,115,122, 4,306,016, and 4,471,044, and the like. Sensitizing dyes having a nucleating substituent in the dye molecule, as described in U.S. Patent No. 718,470; thiourea-bonded acylhydrazine compounds, as described in U.S. Patent Nos. 4,030,925, 4,031,127, 4,245,037, 4,255,511, 4,266,013, 4,276,364, and British Patent No. 2,012,443; and thioamide rings, or heterocyclic groups such as triazoles and tetrazoles, as bonded as adsorptive groups, as described in U.S. Patent Nos. 4,080,270, 4,278,748, and British Patent No. 2,011,391B, are usable.

[0090] The amount of nucleating agent used here is desirably an amount that gives a sufficient maximum density when the internal latent image emulsion is developed with a surface developer. In practice, the appropriate content can vary over a wide range because it depends on the characteristics of the silver halide emulsion used, the chemical structure of the nucleating agent, and the development conditions, but a practically useful range is about 0.1 mg to 5 g per mole of silver in the internal latent silver halide emulsion, and preferably about 0.5 mg to 2 g per mole of silver. When the nucleating agent is contained in a hydrophilic colloid layer adjacent to an emulsion layer, it may be contained in the same amount as above relative to the amount of silver contained in the internal latent emulsion of the same area.

[0091] In the present invention, silver halide grains of various shapes can be used. Examples include grains having regular crystal shapes such as cubes, octahedrons, tetradecahedrons, and rhombic dodecahedrons, as well as grains having irregular crystal shapes such as spheres and plates, grains having highly ordered faces ((hkl) faces), and mixtures of grains of these crystal shapes. For grains having highly ordered faces, see Journal of Imaging Science, Vol. 30 (1986), pp. 247-254.

[0092] The silver halide grains used in the present invention may be regular crystals not containing twin planes, but may be selected according to the purpose from examples such as single twin crystals containing one twin plane, parallel multiple twin crystals containing two or more parallel twin planes, and non-parallel multiple twin crystals containing two or more non-parallel twin planes, as explained in "Fundamentals of the Photographic Industry," Silver Halide Photography, edited by the Photographic Society of Japan (Corona Publishing Co.), p. 163. Furthermore, an example of mixing grains of different shapes is disclosed in U.S. Pat. No. 4,865,964, and this method can be selected if necessary.

[0093] In particular, in view of ease of controlling the sensitivity of re-reversal negative images, a core / shell type internal latent image type silver halide emulsion is preferably used in the present invention. Examples of the core / shell type internal latent image type silver halide emulsion include conversion type silver halide emulsions as described in U.S. Patent Nos. 2,456,953 and 2,592,250, layered structure type silver halide emulsions in which the halogen composition of the first phase and the second phase are different as described in U.S. Patent No. 3,935,014, and metal ion-doped silver halide emulsions. Other examples of core / shell type silver halide emulsions include those described in U.S. Patent Nos. 3,206,313, 3,317,322, 3,761,266, 3,761,276, 3,850,637, 3,923,513, 4,035,185, 4,184,878, 4,395,478, 4,504,570, JP-A Nos. 57-136641, 61-3137, 61-299155, and 62-208241. The shell of the present invention refers to a silver halide phase formed after chemical sensitization of silver halide grains forming the core in the process of preparing an emulsion. The shell production method can be based on the examples in JP-A-63-151618, and U.S. Patent Nos. 3,206,316, 3,317,322, 3,761,276, 4,269,927, and 3,367,778, etc. In this case, the core / shell molar ratio (weight molar ratio) is preferably 1 / 30 to 5 / 1, more preferably 1 / 20 to 2 / 1, and even more preferably 1 / 10 to 1 / 1.

[0094] In view of the high sensitivity of the reversal positive image, the low sensitivity of the reversal negative image, and excellent storage stability of the photosensitive material in an unexposed state, it is preferred that the grains used in the core / shell type internal latent image type silver halide emulsion of the present invention have a metal complex containing a cyan ligand doped in the core of the grain. Specific examples of the structure, amount of addition, and structure of the core / shell emulsion are described in JP-A Nos. 2002-40607 and 2003-107616.

[0095] In the present invention, various antifoggants, photographic stabilizers, etc. may be used to prevent a decrease in sensitivity or the occurrence of fogging, and known additives for adjusting the performance of the photosensitive element may be used. These additives include those described in JP-A Nos. 2002-40607 and 2003-107616.

[0096] Next, the diffusion transfer photosensitive material preferably used in the present invention will be described.

[0097] The most typical form of the diffusion transfer material of the present invention is a color diffusion transfer film unit, and its typical form is one in which an image-receiving element 2 and a photosensitive element 3 are laminated on a single transparent support 1, and after the transfer image is completed, there is no need to peel the photosensitive element 3 from the image-receiving element 2.

[0098] More specifically, the image-receiving element 2 comprises at least one mordant layer. In a preferred embodiment of the photosensitive element 3, the image-receiving element 2 comprises a combination of a blue-sensitive emulsion layer, a green-sensitive emulsion layer, and a red-sensitive emulsion layer, each of which is combined with a yellow dye image-forming compound, a magenta dye image-forming compound, and a cyan dye image-forming compound. A white reflective layer containing a solid pigment such as titanium oxide is provided between the mordant layer and the photosensitive layer or the layer containing the dye image-forming compound, so that the transferred image can be viewed through the transparent support 1. A light-shielding layer may be provided between the white reflective layer and the photosensitive layer to enable development processing to be completed in bright light. If desired, a release layer may be provided at an appropriate position to enable peeling of all or part of the photosensitive element from the image-receiving element. Such an embodiment is described, for example, in JP-A-56-67840 and Canadian Patent No. 674,082.

[0099] Furthermore, the dye image-forming compounds to be combined with the emulsion layers having different photosensitive wavelengths are not limited to the three primary colors of yellow, magenta, and cyan, but can be freely selected. A mixture of multiple colors may also be used. By mixing these three primary colors in a well-balanced manner, it is possible to form an image with a color tone that is roughly close to gray.

[0100] The dye image-forming substance used in the present invention is a non-diffusible compound which releases a diffusible dye (which may be a dye precursor) in association with silver development, and is represented by the general formula (II).

[0101] General formula (II): (DYE-Y)n-Z {In formula (II), DYE represents a dye group, a dye group temporarily short-wave irradiated or a dye precursor group; Y represents a simple bond or a bonding group; Z represents a group having a property of causing a difference in the diffusibility of the compound represented by (DYE-Y)n-Z corresponding to the photosensitive silver salt having an image-wise latent image; n represents 1 or 2, and when n is 2, the two DYE-Ys may be the same or different.}

[0102] This compound is described in "The Theory of the Photographic Process", 4th Edition.

[0103] Specific examples of Z in this compound include those that are oxidized and cleaved upon development to release a diffusible dye. Specific examples of Z are those described in U.S. Patent Nos. 3,928,312, 3,993,638, 4,076,529, 4,152,153, 4,055,428, 4,053,312, 4,198,235, 4,179,291, 4,149,892, 3,844,785, 3,443,943, 3,751,406, 3,443,939, 3,443,940, 3,628,952, 3,980,479, 4,183,753, 4,142,891, 4,278,750, and 4,139,3 79, 4,218,368, 3,421,964, 4,199,355, 4,199,354, 4,135,929, 4,336,322, 4,139,389, JP-A-53-50736, 51-104343, 54-130122, 53-110827, 56-12642, 56-16131, 57-4043, 57-650, 57-20735, 53-69033, 54-130927, 56-164342, 57-119345, and the like. Particularly preferred groups for Z include N-substituted sulfamoyl groups (wherein the N-substituent is a group derived from an aromatic hydrocarbon ring or heterocycle).

[0104] <<Processing Element (Pod)>> The above-described configuration of the image-receiving element 2 and the photosensitive element 3 can be further combined with a pod 14 (see Figure 1), which is a container (processing element) containing an alkaline processing solution and which can be ruptured by pressure. In particular, in a non-peelable film unit in which three image-receiving elements 2 and photosensitive elements are laminated on one support, the pod 14 is preferably positioned between the photosensitive element 3 and the cover sheet 4 laminated thereon. The pod 14 preferably contains either or both of a light-blocking agent (carbon black, a dye whose color changes depending on pH, etc.) and a white pigment (titanium oxide, etc.). The spread thickness of the processing solution is preferably 40 to 80 μm.

[0105] Furthermore, in a film unit of a color diffusion transfer system, it is preferable that a neutralization timing mechanism consisting of a combination of a neutralization layer and a neutralization timing layer is incorporated in the cover sheet 4. Preferred embodiments of the mono-sheet laminate 10 include those described in JP-A Nos. 2001-22039 and 2003-43650, those of the processing liquid pod described in JP-A No. 11-334766, and those of the film pack described in JP-A No. 7-159931.

[0106] Constituent components of the materials that can be used in the mono-sheet laminate 10, such as alkaline developers, light-shielding materials, transparent supports, image-receiving layers, white reflective layers, color-mixing inhibitors, high-boiling organic solvents, layers with neutralizing functions, surfactants, and polymer latexes, can be those described in JP-A Nos. 2002-4067, 2003-107616, and 2006-113291.

[0107] In the image forming method of the first embodiment, as described above, a latent discharge image is formed on the photosensitive element 3 by spark discharge, and after discharging the image, an alkaline processing liquid contained in the pod 14 is spread between the photosensitive element 3 and the cover sheet 4 to develop the latent image and form a discharge image.

[0108] <Exposure with Visible Light> In the present invention, exposure with visible light can be carried out in addition to exposure by discharge.

[0109] The order of the steps when performing exposure to visible light is not particularly limited, and the exposure by discharge may be performed before, after, or simultaneously with the exposure to visible light. Furthermore, each exposure may be performed once or multiple times. Furthermore, the exposure step with visible light also includes a mode in which no visible light is irradiated in order to produce black.

[0110] There are no particular limitations on the order or interval between exposure by discharge and exposure by visible light. When discharge exposure is performed first, the interval between the two exposures can be, for example, from simultaneous exposure to 5 years, preferably from about 1 minute to 1 year. For example, in an embodiment in which a photosensitive material exposed by discharge at the time of shipment of a photosensitive material product is subjected to another exposure by a user, the interval between the two exposures is preferably from about 1 day to 3 years.

[0111] Normal visible light photography can capture images of subjects illuminated by sunlight or general-purpose light sources (incandescent lamps, fluorescent lamps, light-emitting diodes (LEDs), electroluminescence (EL), strobes, etc.) Also, a visible light source can be incorporated into a known exposure system.

[0112] For example, Japanese Patent Nos. 3818563, 3818564, 2662442, JP-A-2000-313137, JP-A-2003-156733, and JP-A-11-344772 describe devices that use LEDs, ELs, light emitters, and liquid crystal segments in combination.

[0113] As described above, according to the image forming method of the first embodiment, it is possible to form (record) a discharge image on the mono-sheet laminate 10 with high reproducibility of discharge behavior and with suppressed occurrence of processing defects due to dust adhesion, etc.

[0114] Here, "highly reproducible" does not mean that a discharge image of the same shape is formed, but rather that discharge of a state that is recorded on a photographic light-sensitive element can be caused with high reproducibility and can be recorded as a photographic image.

[0115] The light emitted by electrostatic discharge consists of a collection of minute discharges that occur in a chain reaction after dielectric breakdown between charged materials. Therefore, it is impossible to reproduce the light emitted by electrostatic discharge, including its microstructure, exactly the same, and no two electrostatic discharge images can ever be created identically. A typical example of an electrostatic discharge image is a well-known image with a dendritic pattern known as a Lichtenberg pattern. Therefore, each discharge image obtained by this invention, which directly records actual electrostatic discharges, is highly unique and completely different from images obtained by exposing and printing them separately. It should also be understood that images obtained by overlaying a conventional photographic image on an electrostatic discharge image obtained in this way will naturally be even more unique.

[0116] [Second Embodiment of Image Forming Method] FIG. 5 is a diagram showing a second embodiment of the image forming method according to the present invention.

[0117] The same parts as those in the first embodiment shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0118] The image forming method of the second embodiment differs from the image forming method of the first embodiment in that the first conductive material 22 is placed at a distance D2 of 0 mm or more and 10 mm or less from the surface of the cover sheet 4 in the normal direction to the surface, and discharge is performed from the electrode 32a of the DC discharge device 30 to the first conductive material 22.

[0119] <First Conductive Material> A first conductive material 22 is placed near the cover sheet 4 of the mono-sheet laminate 10, and electrostatic discharge occurs near the first conductive material 22 by discharging from the electrode 32a of the DC discharge device 30 to the first conductive material 22 or by contacting the electrode 32a of the DC discharge device 30 with the first conductive material 22, thereby forming a latent discharge image on the photosensitive element 3. A preferred embodiment is one in which discharge occurs from the electrode 32a of the DC discharge device 30 to the first conductive material 22.

[0120] The first conductive material 22 is preferably highly conductive, and examples thereof include metals, carbons having a graphene structure, metal oxides, and salts. These materials may be used alone or in combination to form alloys or composite salts, or these materials may be dispersed in a binder and molded. Furthermore, the first conductive material 22 may be vapor-deposited on a film, or may have a thin film of a metallic material formed on the surface by plating or applying an ink composition.

[0121] In the image forming method of the second embodiment, it is easy to control the distance D2 between the first conductive material 22 and the cover sheet 4, and discharge can be stably generated.

[0122] In this second embodiment, the distance D2 between the first conductive material 22 and the cover sheet 4 is preferably 0 mm or more and 10 mm or less, more preferably 0 mm or more and 2 mm or less, even more preferably 0 mm or more and 1 mm or less, and particularly preferably 0 mm or more and 0.5 mm or less.

[0123] Furthermore, in the second embodiment, it is preferable that the distance between the electrode 32a of the DC discharge device 30 and the cover sheet 4 is 20 mm or less, and the distance D2 between the first conductive material 22 and the cover sheet 4 is satisfied, and more preferably 15 mm or less.

[0124] The distance D2 can be set by placing an insulating member between the first conductive material 22 and the cover sheet 4. Alternatively, a portion of the first conductive material 22 can be joined to an insulating member and fixed onto the cover sheet 4 via the insulating member.

[0125] When the shape of the first conductive material 22 facing the cover sheet 4 is three-dimensional, it is preferable that the three-dimensional shape includes an area where the difference from the shortest distance to the cover sheet 4 is 4 mm or less, and more preferably 2 mm or less. Discharges of different intensities reflecting the three-dimensional shape are likely to occur, and the shape of the first conductive material 22 is likely to be reflected in the discharge image. The three-dimensional shape may include curved surfaces or acute-angled protrusions. It may also include recesses.

[0126] In the second embodiment, the volumetric size of the first conductive material 22, when converted into a cube of the same material, is preferably such that one side of the cube is 0.5 mm to 20 mm, and may also be approximately 1 to 15 mm or 2 to 8 mm.

[0127] An amount of material equivalent to this volume can be processed into the desired shape. For example, when viewed from directly above, the shape may be a circular, elliptical, or polygonal columnar shape with a thickness of approximately 0.3 to 5 mm, or may have holes or three-dimensional irregularities. Furthermore, when these first conductive materials 22 are placed on the cover sheet 4, they may be used alone or in combination, and when multiple first conductive materials 22 are used, they may be electrically connected to each other.

[0128] <Discharge Voltage> The voltage of the DC discharge device 30 is preferably in the range of 3 kV to 30 kV, and more preferably 6 kV to 30 kV.

[0129] The number of discharges may be one or more. When the number of discharges is more than one, there is no particular limit to the time interval between discharges. If the number of discharges is too many, the entire photosensitive element 3 will be covered by the discharge light, so it is preferable to adjust the number of discharges appropriately to obtain the desired discharge image.

[0130] According to the image forming method of the second embodiment, it is possible to obtain the same effect as in the first embodiment, and compared to the first embodiment, it is possible to stably generate discharge using the first conductive material 22, and it is also possible to record a discharge image corresponding to the shape (including three-dimensional shapes) and size of the first conductive material 22.

[0131] [Third Embodiment of Image Forming Method] FIG. 6 is a diagram showing a third embodiment of the image forming method according to the present invention.

[0132] The same parts as those in the first embodiment shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0133] The image forming method of the third embodiment differs from the first embodiment in that a sheet-like insulating material 24 is placed at a distance D3 of 0 mm or more and 15 mm or less from the surface of the cover sheet 4 in the normal direction to the surface, corona discharge is performed on the sheet-like insulating material 24 from the electrode 32a of the DC discharge device 30, static electricity is charged to the sheet-like insulating material 24, dielectric breakdown occurs at at least one point of the statically charged sheet-like insulating material 24, and the charged static electricity is discharged.

[0134] <Sheet-shaped insulating material> The sheet-shaped insulating material 24 is a sheet-shaped product that is unlikely to leak electric charge. The half-life of the electric charge at 25°C and 30% RH (relative humidity) is preferably 1 minute or more, more preferably 2 minutes or more, and even more preferably 3 minutes or more.

[0135] Specific materials include, but are not limited to, organic and inorganic materials, and preferably thermoplastic resins primarily composed of organic polymer materials. Examples of these resins include polyolefins (polyethylene, polypropylene, etc.), polystyrenes (polystyrene, polymethylstyrene, etc.), polycarbonates, poly(meth)acrylic resins (polymethyl methacrylate, polyethyl methacrylate, etc.), SBR resin (styrene-butadiene rubber), ABS resin (acrylonitrile-butadiene-styrene resin), MABS resin (transparent ABS resin), urethane resin, melamine resin, nylons, cellulose-based resins, and gelatins. These thermoplastic resins may also contain colorants, pigments, fillers, plasticizers, surfactants, etc., as long as they have insulating properties. Inorganic materials such as glass and mica can also be used.

[0136] The sheet-like article refers to an article having a shape factor K, as defined below, of 2 or more.

[0137] In the state where the device is placed on the cover sheet 4, the plane of the cover sheet 4 and a plane perpendicular thereto are assumed.

[0138] Within the exposed surface, the shape factor K is defined as "projected area" divided by "vertical thickness." In this embodiment, the shape factor K may be 2 or more, and is preferably 2 or more and 200,000 or less, more preferably 10 or more and 100,000 or less, and even more preferably 20 or more and 100,000 or less. Within this range, static electricity can be accumulated effectively, which is preferable.

[0139] The simplest form is a thickness of about 0.3 to 2 mm and an area of ​​25 to 10,000 mm. 2 Examples of suitable plastic resins include those in the form of a plate. They may have holes or may be comb-shaped. Also, fibrous materials may be woven into a cloth.

[0140] The surface may be embossed to have minute irregularities, and the difference in irregularities may be about 2 to 100 μm.

[0141] <Distance between the sheet-like insulating material and the cover sheet> The distance D3 between the sheet-like insulating material 24 and the cover sheet 4 refers to the shortest distance between them in the normal direction from the surface of the cover sheet 4. Specifically, the distance between them is preferably 0 to 15 mm, more preferably 0 to 10 mm, and most preferably 0 to 5 mm. If the distance D3 is too large, the discharge light will diffuse before reaching the photosensitive element 3, resulting in a blurred discharge image being recorded.

[0142] Here, the distance D3 between them is defined as the shortest distance, but even if the distance between them is 0, it is preferable that there be gaps where the sheet-like insulating material 24 is not in contact with the cover sheet 4 at each point where it faces the cover sheet 4, and for example, gaps of about 0.005 to 2 mm, or 0.05 to 1 mm may be present. Furthermore, the surface shape of the sheet-like insulating material 24 may be changed from a flat shape to a stepped, conical, hemispherical, or other shape to change the microscopic positional relationship between the insulating material sheet and the cover sheet, thereby adjusting the charging state.

[0143] <Corona Discharge> In the image forming method of the third embodiment, corona discharge is applied to the sheet-shaped insulating material 24 from the electrode 32 a of the DC discharge device 30 .

[0144] The sheet-like insulating material 24 can be charged by being bombarded with charged particles generated by corona discharge. The charging of the sheet-like insulating material 24 can also induce charging of individual components of the mono-sheet laminate 10. This results in a state where multiple charged materials are stacked on the photosensitive element 3. By locally causing insulation breakdown in this state, an electron avalanche can be induced from that point and around the surrounding area, recording a distinctive electrostatic pattern. In this state, the distance between the photosensitive element 3 and the discharge location is short, resulting in little diffusion of discharge light and a sharp discharge image with little image bleeding.

[0145] <Preferred Methods of Dielectric Breakdown> <First Method of Dielectric Breakdown> In the image forming method of the third embodiment, a first method of causing dielectric breakdown in the charged sheet-like insulating material 24 is to use a sheet-like insulating material 24 having voids penetrating through at least a portion of the sheet-like insulating material 24 in the thickness direction. Then, one method involves bringing an electrode 32a of a DC discharge device 30 close to the voids provided in the sheet-like insulating material 24 to cause dielectric breakdown.

[0146] The existence of a void penetrating in the thickness direction (up and down) of the sheet-shaped insulating material 24 does not necessarily mean that the void is topologically donut-shaped; for example, when viewed from the normal direction to the surface of the cover sheet 4 and from a conical direction tilted 45 degrees from that direction, the void needs to penetrate from the top to the bottom, and the periphery of the void does not need to be completely closed.

[0147] <<Second Method of Dielectric Breakdown>> In the image forming method of the third embodiment, a second method for causing dielectric breakdown in the charged sheet-like insulating material 24 involves placing a conductive material (second conductive material) at at least one point on the surface (upper or lower surface) of the sheet-like insulating material 24. Then, discharge is performed from the electrode 32a of the DC discharge device 30 to the second conductive material placed on the charged surface of the sheet-like insulating material 24. In this case, the second conductive material may be placed in advance in contact with the mono-sheet laminate 10 below the sheet-like insulating material 24, and the sheet-like insulating material 24 may be charged by corona discharge from that state, or the second conductive material may be placed on the sheet-like insulating material 24 after charging.

[0148] <Third method of dielectric breakdown> In the image forming method of the third embodiment, a third method of dielectric breakdown of the charged sheet-like insulating material 24 includes a method of partially reducing the distance between the sheet-like insulating material 24 and the mono-sheet laminate 10 (cover sheet 4) to cause dielectric breakdown at at least one point on the sheet-like insulating material 24.

[0149] That is, the sheet-like insulating material 24 is placed at a distance of 1 mm to 15 mm from the surface of the cover sheet 4 in the normal direction to the surface, with at least a gap being provided between the sheet-like insulating material 24 and the cover sheet 4. Then, by shortening the physical distance between the sheet-like insulating material 24 and the mono-sheet laminate 10 when they are charged and in close proximity, the insulation limit voltage is exceeded, causing a discharge between them.

[0150] Specifically, the distance can be reduced by bending one or both of the charged sheet-like insulating material 24 and the mono-sheet laminate 10. For example, the sheet-like insulating material 24 can be bent by pressing an insulating rod from above the sheet-like insulating material 24. Alternatively, the discharge electrode rod 32 used for corona discharge may be used to partially press the sheet-like insulating material 24.

[0151] The third method of dielectric breakdown does not exclude a mode in which dielectric breakdown occurs by reducing the distance between the sheet-like insulating material 24 and the mono-sheet laminate 10 while keeping the distance substantially constant in all opposing regions.

[0152] In the image forming method of the third embodiment, a conductive connecting member 6 for grounding can be attached in a frame-like manner to the side of the mono-sheet laminate 10 that is not the surface to be exposed.

[0153] <Coloring of Sheet-like Insulating Material> In the image forming method of the third embodiment, it is possible to color the sheet-like insulating material 24. In one preferred embodiment, the sheet-like insulating material 24 absorbs at least a portion of light having a wavelength in the photosensitive region of the photosensitive element 3.

[0154] Generally, the silver halide photographic light-sensitive element 3 is designed to have sensitivity to ultraviolet to short-wave blue light in its inherent region (approximately 300 to 450 nm) and to the visible light region (approximately 400 to 700 nm). "Absorbing at least a portion of light of wavelengths in the light-sensitive region" means that the transmittance at a specific wavelength measured in the normal direction in a sheet form actually used on the cover sheet 4 is absorbed to 50% or less. To obtain a more pronounced effect, the transmittance at a specific wavelength can be reduced to 10% or less, preferably 1% or less, and even more preferably 0.1% or less.

[0155] By reducing this transmittance, it is possible to absorb the diffused light and reflected light that spreads near the surface of the cover sheet 4. This makes it possible to discolor the light that is exposed after repeated diffusion and reflection, and also to suppress multiple scattering of the discharge light, thereby obtaining a sharp image.

[0156] The amount of light reaching the surface of the photosensitive element 3 from above the sheet-like insulating material 24 can also be changed. Specifically, examples include stray light during operation and ultraviolet to blue light generated from the electrode 32a of the DC discharge device 30 during corona discharge. For example, to cut light in the ultraviolet to blue range, ultraviolet absorbers, yellow dyes, yellow pigments, etc. can be used to significantly reduce the blue light of corona discharge. The degree of coloring can be set within any range so that the expected effect can be achieved. The materials used for this purpose are not limited to organic or inorganic, and colorants such as dyes and pigments can be used.

[0157] Another preferred embodiment of the sheet-like insulating material 24 is one that is substantially impermeable to light of wavelengths in the photosensitive region of the silver halide photographic light-sensitive element 3. "Substantially impermeable to light of wavelengths in the photosensitive region" means that in the sheet form actually used on the cover sheet 4, the transmittance for wavelengths of 300 to 700 nm measured in the normal direction is 1.0% or less. More preferably, it is 0.1% or less. By achieving this level, blue light during corona discharge can be blocked and multiple scattering due to discharge light can be suppressed, resulting in a sharp discharge image.

[0158] In another preferred embodiment, the sheet-like insulating material 24 is substantially opaque to light of wavelengths in the photosensitive region of the silver halide photographic light-sensitive element 3, and in addition, the exposed surface of the light-sensitive element 3 is shielded from light by the sheet-like insulating material 24.

[0159] With this configuration, the photosensitive element 3 can be shielded from external light, and the discharge operation can be performed under visible light. This is a significant advantage as it significantly reduces the burden on the worker. In addition, in this case, it is not necessary to cover the entire exposed surface with only the sheet-like insulating material 24, and it is also possible to implement this as a preferred embodiment even if there are parts that are shielded from light by other means.

[0160] Furthermore, in the embodiment in which the sheet-like insulating material 24 is used on the cover sheet 4, it is easier to obtain a stable charged state against ambient wind and temperature and humidity changes than in the embodiment in which it is not used, and it is easier to obtain a stable discharge image due to the insulation breakdown. This is because the discharge phenomenon recorded on the photosensitive element 3 occurs in the area sandwiched between the sheet-like insulating material 24 and the photosensitive element 3, and this area is less susceptible to ambient wind and temperature and humidity changes. This is very effective in improving the reproducibility of the discharge state.

[0161] <Discharge Voltage> In this embodiment, particularly when the sheet-like insulating material 24 is colored, the amount of light that directly reaches the silver halide photographic light-sensitive element 3 due to discharge light when discharging the sheet-like insulating material 24 is reduced, so that blurring of the recorded discharge image is unlikely to occur. Therefore, a relatively high voltage can be used compared to other embodiments.

[0162] In this case, the voltage of the DC discharge device 30 is preferably in the range of 3 kV to 300 kV, more preferably 6 kV to 100 kV, and even more preferably 6 to 50 kV. The number of discharges may be one or more. When the number of discharges is multiple, there is no particular limitation on the time interval between discharges.

[0163] [Fourth Embodiment of Image Forming Method] FIG. 7 is a diagram showing a fourth embodiment of the image forming method according to the present invention.

[0164] The same parts as those in the third embodiment shown in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0165] The image forming method of the fourth embodiment is similar to the third embodiment shown in Figure 6 in that a sheet-like insulating material 24 is placed on a cover sheet 4, but differs from the third embodiment in that a conductive material (third conductive material 26) that contacts or is close to the cover sheet 4 is placed on the inner surface of the sheet-like insulating material 24 facing the cover sheet 4, a conductive portion 26a that is electrically conductive with the third conductive material 26 is provided, and a conductive portion 26a is provided that is partly exposed on the outer surface of the sheet-like insulating material 24, and an electrode 32a of a DC discharge device 30 is brought into contact with or close to a part of the exposed conductive portion 26a, causing discharge from the electrode 32a to the third conductive material 26 via the conductive portion 26a.

[0166] <Sheet-Shaped Insulating Material> The sheet-shaped insulating material 24 can be the same as that described in the third embodiment shown in FIG. 6, including the material and coloring in the visible light region.

[0167] Furthermore, the sheet-like insulating material 24 in the image forming method of the fourth embodiment blocks at least a portion of wavelengths in the visible light range. Blocking at least a portion of wavelengths in the visible light range means that the light transmittance at that wavelength is 0.1% or less. For example, when working under a red LED with a peak wavelength of 650 nm, reducing the transmittance in the LED's emission wavelength range can block light from reaching the photosensitive element 3 from the outside. When working under lighting that covers the entire visible light range, reducing the transmittance for all wavelengths in that range can substantially block the photosensitive element 3 from external light. Carbon black, which absorbs light over a wide range from ultraviolet to infrared, is effective for light blocking. For example, by covering substantially the entire exposed surface of the photosensitive element 3 with a sheet-like insulating material 24 containing a sufficient amount of carbon black, discharge image formation can be performed under ordinary visible light.

[0168] <Installation of third conductive material> In the image forming method of the fourth embodiment, a third conductive material 26 is installed on the inner surface of the sheet-like insulating material 24 facing the cover sheet 4 in contact with or close to the cover sheet 4, and the third conductive material 26 is electrically connected to the outer surface of the sheet-like insulating material 24 by a conductive portion 26a.

[0169] The third conductive material 26 may be the second conductive material used in the second method for causing dielectric breakdown of the charged sheet-like insulating material 24 in the image forming method of the third embodiment.

[0170] The third conductive material 26 may be in contact with the cover sheet 4 or may be in a state close to the cover sheet 4 but not in contact therewith.

[0171] The distance between the third conductive material 26 and the cover sheet 4 can be adjusted by inserting an insulating material of a specific thickness or shape into a portion of the third conductive material 26. Alternatively, the distance can be adjusted between the cover sheet 4 and the sheet-like insulating material 24 that secures the third conductive material 26. In this case, the distance can be adjusted by changing the shape of the sheet-like insulating material 24, or by using a different material as a spacer. The material and three-dimensional structure of the third conductive material 26 can be the same as those described in the image forming method of the third embodiment. The third conductive material 26 preferably has a three-dimensional structure. When the third conductive material 26 is placed in contact with or close to the cover sheet 4, the shortest distance between them is preferably 0 to 15 mm, more preferably 0 to 10 mm, and most preferably 0 to 5 mm.

[0172] When the third conductive material 26 is subjected to multiple discharges, the distance does not need to be constant for each discharge. For example, when a metal member is used as the third conductive material 26, by contacting it with the cover sheet 4 in its original shape, it is possible to transfer a shape that is identical to the appearance of the third conductive material 26 and that is not reversed left to right onto the photosensitive element 3. Therefore, even parts that display mirror images, such as character information, can be used as is, which is highly convenient in that it does not require the preparation of special metal parts for electrostatic image formation.

[0173] The third conductive material 26 is required to establish electrical continuity between the inner surface side and the outer surface side of the sheet-like insulating material 24 .

[0174] One preferred embodiment of this means is to use a metallic material for the third conductive material 26, with a convex conductive portion 26a integrally formed in part of it, as shown in Figure 7, and to provide physical holes in the sheet-like insulating material 24, insert the convex conductive portion 26a into the holes, and extend part of the conductive portion 26a to the outer surface of the sheet-like insulating material 24.

[0175] This embodiment is easy because it is not necessary to add a new member for imparting conductivity to the original third conductive material 26. In addition, the protrusions (conductive portions 26a) can be used to fix the third conductive material 26 to the sheet-like insulating material 24, and the distance between the photosensitive element 3 and the third conductive material 26 can be set.

[0176] Another preferred embodiment is a method of using a detachable conductive part to establish electrical continuity between the third conductive material on the inner surface side and the outer surface side of the sheet-like insulating material 24. Specifically, for example, a method can be used in which a screw hole is drilled in the third conductive material on the inner surface side of the sheet-like insulating material 24, a screw is inserted into the screw hole to form a convex part, and the convex part (screw) is extended to the outer surface side.

[0177] In yet another preferred embodiment, electrical continuity is established between the inner and outer surfaces of the sheet-like insulating material 24 by passing a flexible metal vapor deposition tape, which is a conductive material, through holes formed in the sheet-like insulating material 24. In this method, the third conductive material on the inner surface side can also be fixed with the metal vapor deposition tape.

[0178] In yet another preferred embodiment, holes of a size required for electrical continuity are opened in the sheet-like insulating material 24, a flat third conductive material is placed on the inner surface of the sheet-like insulating material 24 to cover the holes, and electrical continuity is established directly from the outer surface through the holes to the third conductive material. In either embodiment, it is preferable to cover the periphery of the holes formed in the sheet-like insulating material 24 with light-shielding tape or the like to prevent light from entering from outside.

[0179] The discharge method in the image forming method of the fourth embodiment involves bringing electrode 32a of the DC discharge device 30 into contact with or close to third conductive material 26 on the outer surface side of sheet-like insulating material 24 (in the example of Figure 7, conductive portion 26a formed integrally with third conductive material 26 exposed on the outer surface side of sheet-like insulating material 24), and discharging from the third conductive material 26 on the inner surface side (photosensitive element surface side).

[0180] At this time, a discharge may be caused with the electrode 32a of the DC discharge device 30 in close proximity to the conductive portion 26a on the outer surface side, thereby causing a discharge from the third conductive material 26 on the inner surface side of the sheet-like insulating material 24. This method is preferable because the discharge phenomenon can be observed visually.

[0181] A preferred voltage range is 3 kV to 300 kV, and more preferably 6 kV to 100 kV. The number of discharges may be one or more. Discharges are preferably performed multiple times, since this allows for detailed depiction of a discharge image that depends on the shape of third conductive material 26 and the fine shape of third conductive material 26.

[0182] In the image forming method of the fourth embodiment, a conductive connecting member 6 for grounding can be attached in a frame-like manner to the side of the mono-sheet laminate 10 that is not the exposed surface. By providing the conductive connecting member 6 uniformly around the image in a frame-like manner, dielectric breakdown can be stably induced.

[0183] <Combination of Each Embodiment> Different methods among the image forming methods of the first to fourth embodiments described above may be used for each exposed region in one mono-sheet laminate 10. Also, image forming methods of different embodiments may be used in combination sequentially.

[0184] In the image forming method of the second embodiment, a sheet-like insulating material 24 may be placed between the electrode 32a of the DC discharge device 30 and the first conductive material 22. In this case, the sheet-like insulating material 24 may have a gap extending from top to bottom, and may absorb at least a part of the wavelengths in the photosensitive region of the silver halide photographic light-sensitive element 3.

[0185] [Exposed Mono-Sheet Laminate] In a first embodiment of the exposed mono-sheet laminate according to the present invention, at least one discharge exposure has been performed by at least one of the image forming methods according to the first to fourth embodiments described above, so that a latent discharge image has been formed on the photosensitive element, and the mono-sheet laminate has not yet been subjected to development processing with an alkaline processing solution contained in a pod integrated into the mono-sheet laminate.

[0186] Preferred embodiments of the exposed mono-sheet laminate include those in which the first exposure is performed by discharge exposure, and an image of lightning-like branching, an image in which the shape of a conductive material is transferred, or an image in which the shape of a colored member placed on the surface of the cover sheet is transferred, is exposed.

[0187] A user can set the exposed mono-sheet laminate of the first embodiment in a camera, photograph and expose a normal subject through the optical lens of the camera, and output the image, or set the exposed mono-sheet laminate in a positive general-purpose printer, expose the desired digital image information in the general-purpose printer, and output the image.

[0188] Even if conditions such as voltage and electrode shape are adjusted, the discharge image will not be exactly the same every time, so each photograph is highly unique.

[0189] The second embodiment of the exposed mono-sheet laminate according to the present invention is similar to the first embodiment in that at least one discharge exposure is performed to form a latent discharge image on the photosensitive element, but differs from the first embodiment in that at least one visible light exposure is also performed. Note that the order of discharge exposure and visible light exposure does not matter, and they may be performed simultaneously.

[0190] The mono-sheet laminate of the second embodiment has been exposed to discharge and visible light, but has not yet been subjected to development processing with an alkaline processing solution contained in a pod integrated into the mono-sheet laminate.

[0191] A second preferred embodiment of the exposed mono-sheet laminate is one in which, by discharge exposure, a lightning-like branched image, an image in which the shape of a conductive material is transferred, an image in which the shape of a colored member placed on the surface of a cover sheet is transferred, or the like, is exposed, and then a desired digital image is exposed by visible light exposure, in any order.

[0192] A user can set the exposed mono-sheet laminate of the second embodiment in a camera and release the shutter while the optical lens of the camera is shielded from light, thereby causing the camera to carry out a development process and output an image, or can set the exposed mono-sheet laminate in a positive-type general-purpose printer and cause the general-purpose printer to carry out a development process and output an image without exposing an additional image.

[0193] The present invention will be described in more detail below based on examples. The materials, conditions of use, procedures for image formation, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0194] Example 1 Preparation of Mono-Sheet Laminate A sample was prepared in accordance with the description of Example 1 in JP-A No. 2002-40607, which was a direct positive silver halide photographic light-sensitive material in which an image-receiving element 2 and a light-sensitive element 3 were coated on the same transparent support 1 as shown in FIG. 2, and an image was formed using a cover sheet 4 and an alkaline processing composition according to the following steps.

[0195] Photosensitive element 3 was stored for 7 days under conditions of 30° C. and 60% relative humidity after coating. Unless otherwise specified below, photosensitive element 3 was handled in a dark room.

[0196] The photosensitive region of the photosensitive element 3 is in the vicinity of 400 nm to 700 nm, and although the sensitivity is relatively low, it is sensitive up to the ultraviolet region of about 350 nm.

[0197] The photosensitive element 3 and cover sheet 4 were bonded together at the three frame edges of the final image with adhesive spacers 5 having a thickness of 55 μm. A pressure-rupturable container containing an alkaline processing solution was joined to one edge of the photosensitive element 3 and cover sheet 4, leaving a gap between them, to form a mono-sheet laminate 10. Furthermore, a tape containing an aluminum vapor-deposited layer (a conductive connecting member 6 for grounding) was attached in the shape of a frame to the side opposite the exposed surface. The overall size of the mono-sheet laminate 10, including the pod 14 containing the processing solution, was 54 mm × 86 mm, and the image surface for observation inside the frame was 46 mm × 62 mm (see Figure 1).

[0198] [Discharge] Electricity was generated in a dark room using a Van de Graaff type generator as a DC discharge device.

[0199] A discharge electrode was connected to the aluminum sphere electrode side of the Van de Graaff generator, and the polarity of the discharge electrode was set to be positive.

[0200] The discharge electrode used was a stainless steel cylinder with a tip diameter of 4.0 mm and a length of 8 cm, the handle of which was protected by an insulator.

[0201] When the tip of the cylinder is held in the air, a corona discharge occurs that is barely visible to the naked eye.

[0202] The voltage was adjusted to a range of 20 kV to 30 kV, the room temperature was 22 to 25°C, and the relative humidity was 40 to 50%.

[0203] When the discharge electrode was brought close to a metal piece connected to earth, a spark discharge observable with the naked eye was observed at a distance of about 10 to 20 mm.

[0204] The mono-sheet laminate 10 was placed with the exposed surface facing up on a grounded aluminum plate 20. A conductive connecting member 6 for grounding was attached in a frame shape to the outer periphery of the side opposite to the exposed surface, and was in contact with the grounded aluminum plate 20 (see Figure 4).

[0205] "Experiment 101" The electrode 32a at the tip of the discharge electrode rod 32 of the Van de Graaff generator was brought close to the approximate center of the cover sheet 4 on the exposed surface of the mono-sheet laminate 10, and a spark discharge was generated so that the distance between the electrode 32a and the cover sheet 4 was 15 mm. This operation was repeated three times, and then the discharge operation was completed.

[0206] After the discharge, the mono-sheet laminate was irradiated with an ionizer to carry out a static elimination treatment.

[0207] The alkaline processing composition was spread to a thickness of 55 μm using a pressure roller between the photosensitive element 3 and the cover sheet 4. The processing was carried out at 25° C., and the discharge image formed after 10 minutes was observed.

[0208] "Experiment 102" and "Experiment 103" In experiment 101, discharge was performed by changing the conditions such as the shape of the tip of the discharge electrode and the distance between the electrode 32a and the cover sheet 4 as shown in Table 1 below.

[0209] Other than that, the alkaline processing composition was spread and development processing was carried out in exactly the same manner as in Experiment 101, and Experiments 102 and 103 were carried out.

[0210] "Experiment 104" In Experiment 101, the tip of the discharge electrode rod of a Van de Graaff type generator was brought close to the silver halide photographic light-sensitive element before it was assembled into a mono-sheet laminate, and a spark discharge was generated by keeping the distance between the electrode and the light-sensitive element at 15 mm. This operation was repeated three times, and then the discharge operation was completed.

[0211] After the discharge, the photosensitive element was irradiated with an ionizer to carry out a static elimination process.

[0212] The photosensitive element and cover sheet thus obtained were adhered to the frame portions of three sides of the final image formed thereon with spacers having adhesive. A pressure-rupturable container containing an alkaline processing solution was joined to one side of the photosensitive element and cover sheet, leaving a gap between them, to form a mono-sheet laminate.

[0213] The alkaline processing composition was spread between the photosensitive element and the cover sheet to a thickness of 55 μm using a pressure roller. The processing was carried out at 25° C., and the discharge image formed after 10 minutes was observed.

[0214] "Experiment 105" In Experiment 104, static elimination, assembly into a mono-sheet laminate, and development processing were carried out in the same manner as in Experiment 104, except that the tip shape of the discharge electrode and the distance between the electrode and the photosensitive element were changed as shown in Table 1 below.

[0215] In Experiments 104 and 105, discharge was performed without a cover sheet, which differs from Experiments 101 to 103 in that discharge was performed with a cover sheet.

[0216] "Experiment 106" A disk-shaped conductive material (corresponding to the first conductive material 22 shown in Figure 5) made of a zinc-based alloy (containing zinc, aluminum, and copper as main components) with a diameter of 5 mm and a thickness of 1 mm was placed in the approximate center of the cover sheet on the exposed surface of the mono-sheet laminate produced in Experiment 101.

[0217] When the tip of the discharge electrode rod of the Van de Graaff generator used in Experiment 101 was brought 10 mm close to the disc-shaped conductive material, spark discharges were observed between the electrode and the conductive material, and between the conductive material and the edge of the mono-sheet laminate. This operation was repeated three times, and the discharge operation was completed. Thereafter, static elimination and development processing were carried out in the same manner as in Experiment 101.

[0218] "Experiment 107" to "Experiment 112" In Experiment 106, the size and shape of the conductive material and the distance between the conductive material and the cover sheet were changed as shown in Table 2 below, and discharge was performed, but static elimination, assembly into a laminate, and development processing were performed in the same manner as in Experiment 106.

[0219] The distance between the conductive material functioning as the dielectric breakdown member and the cover sheet was adjusted by inserting polyethylene terephthalate sheets of different thicknesses between them.

[0220] "Experiment 113" In Experiment 104, a disk-shaped conductive material made of a zinc-based alloy, 5 mm in diameter and 1 mm thick, was placed approximately in the center of the silver halide photographic light-sensitive element before it was assembled into a mono-sheet laminate. The tip of the discharge electrode rod of a Van de Graaff generator was brought close to this, and spark discharge was generated between the electrode and the conductive material, and between the conductive material and the edge of the mono-sheet laminate. This operation was repeated three times, and the discharge operation was completed. Thereafter, static elimination, assembly into a mono-sheet laminate, and development processing were carried out in the same manner as in Experiment 104.

[0221] The discharge images after development were evaluated as follows.

[0222] (1) Discharge Image In this experimental procedure, no additional exposure other than discharge was performed, so the expected image was a discharge image generated by discharge against a black background. The obtained discharge image was evaluated according to the following criteria.

[0223] (A) The image shows branched streaks of light resembling lightning, which gives the impression of a discharge.

[0224] (B) Light streaks were observed in the formed image, indicating discharge from the conductive material.

[0225] (C) The shadow-like shape of the conductive material was observed in the formed image.

[0226] (D) In ​​the formed image, a yellow-green to black re-inverted negative image was observed within the white discharge light.

[0227] (X) In the formed image, instead of branch-like streaks of light like lightning at the discharge area, an image was observed in which the surrounding area became bright.

[0228] Of these, a rating of (D) indicates that the luminescence intensity is so strong that it appears white to the naked eye, including areas darker than it, but the photosensitive element records the intensity difference as a re-reversed negative image, and is therefore able to record detailed information about the intensity of the discharge.On the other hand, a rating of (X) is undesirable because it is an image with a common defect such as light fogging.

[0229] The evaluation of the discharge image after processing was carried out by listing (A) to (D) and (X) formed in the image together in the evaluation column.

[0230] (2) Processing defects The discharge image after processing was observed to check for areas where the image density had dropped unnaturally. To distinguish from images recorded due to the discharge phenomenon, the cover sheet side, which is the back side of the formed image, was also observed. It was confirmed whether the carbon black in the spread processing solution was uniformly spread, and the results were evaluated according to the following criteria. Three test samples were prepared under the same conditions, and the average score was calculated and evaluated.

[0231] (K) 10 points: Spot-like or trailing processing defects are observed when observed from the image surface or from the processing solution spread side, and the frequency of occurrence is 5 or more per mono-sheet laminate.

[0232] (L) 5 points: When observed from the image surface or from the processing solution spread side, spot-like or trailing processing defects are observed, and the frequency of occurrence is 2 to 4 places per mono-sheet laminate.

[0233] (M) 2 points: When observed from the image surface or from the processing solution spread side, spot-like or trailing processing defects are observed, and the frequency of occurrence is one spot per mono-sheet laminate.

[0234] (N) 0 points: No processing defects are observed when observed from the image surface or from the processing solution development side.

[0235] The conditions and results of each experiment are shown in Tables 1 and 2 below.

[0236]

[0237]

[0238] Table 1 shows that the occurrence of processing defects was suppressed when a silver halide photographic light-sensitive element and a cover sheet were integrated into a mono-sheet laminate according to the image forming method and discharged from above the cover sheet (compare Experiments 101 to 103 with Experiments 104 and 105, and Experiment 106 with Experiment 113).

[0239] Furthermore, if the distance between the electrode and the cover sheet during discharge exceeds 15 mm, the discharge image becomes bright all over, making it impossible to obtain a clear image (comparison of Experiment 101 with Experiments 102 and 103).

[0240] Furthermore, according to Table 2, by placing a conductive material on top of the cover sheet, the behavior of the discharge from the conductive material and the shape of the conductive material itself are recorded in the discharge image (Experiments 106-108, 110-112).

[0241] Furthermore, when the relative humidity in the room was increased to 55-60% and the voltage of the Van de Graaff generator was reduced to 15-19 kV, the frequency of re-inverted negative images recorded in yellow to black decreased, and it was possible to obtain images with an impression dominated by bluish-white discharge images that were closer to the real thing.

[0242] Example 2 [Preparation of mono-sheet laminate and preparation for discharge] A mono-sheet laminate was prepared in the same manner as in Example 1. The mono-sheet laminate was placed on a grounded aluminum plate with the exposed surface facing upward. Preparation for discharge was carried out using the same Van de Graaff generator as in Example 1.

[0243] "Experiment 200" A matte black polystyrene sheet (corresponding to the sheet insulating material 24 shown in Figure 6) measuring 30 mm wide x 40 mm long and 0.4 mm thick was placed in the approximate center of the cover sheet on the exposed surface of the mono-sheet laminate.

[0244] The black polystyrene sheet is an insulating material containing carbon black. The discharge electrode rod of the Van de Graaff generator was scanned over the black polystyrene sheet from a height of approximately 30 mm to 60 mm, a height that would not cause spark discharge, at a moderate in-plane speed of 10 to 20 cm per second for approximately 60 seconds, while changing its position, to generate corona discharge from the tip of the discharge electrode rod. When the mono-sheet laminate was then lifted and stood upright in this state, it was found that the mono-sheet laminate and the black polystyrene sheet were adhered without peeling, and the black polystyrene sheet was charged, resulting in electrostatic force acting between them.

[0245] "Experiment 201" A matte black polystyrene sheet measuring 30 mm wide x 40 mm long and 0.4 mm thick was placed at the center of the cover sheet on the exposed surface of the mono-sheet laminate. The black polystyrene sheet is an insulating material.

[0246] The discharge electrode rod of the Van de Graaff type generator was scanned for approximately 60 seconds on the black polystyrene sheet from a height of approximately 30 mm to 60 mm, which was such that no spark discharge would occur, while changing its position moderately within a plane at a speed of 10 to 20 cm per second, to generate a corona discharge from the tip of the discharge electrode rod.

[0247] For the sample after corona discharge, a discharge electrode was brought close to the boundary between the black polystyrene sheet and the cover sheet from above, allowed to adhere to both, and then quickly removed. At this time, a spark discharge was visible to the naked eye when the distance between the electrode and the black polystyrene sheet was approximately 5 mm, and an accompanying sound was observed. After the discharge, the laminate sample was irradiated with an ionizer and subjected to a static elimination treatment after removing the sheet-like insulating material. An alkaline treatment composition was spread between the photosensitive element and the cover sheet using a pressure roller to a thickness of 55 μm. The treatment was carried out at 25° C., and the discharge image formed after 10 minutes was observed. The evaluation results will be described below along with other experimental conditions of Example 2.

[0248] "Experiment 202" Corona discharge was carried out in the same manner as in Experiment 201, except that a 3 mm diameter hole was opened in the center of the black polystyrene sheet, and a gap was created through the top and bottom of the sheet. The discharge electrode was then brought close to the gap in the center from above, brought into contact with the black polystyrene sheet, and then quickly removed. At this time, a sound believed to be discharge was observed when the distance between the electrode and the black polystyrene sheet was about 5 mm.

[0249] The discharged samples were neutralized in the same manner as in Experiment 201 and then treated.

[0250] "Experiment 203" In Experiment 202, corona discharge was performed in the same manner as in Experiment 201, except that a disk-shaped conductive material (corresponding to the third conductive material shown in Figure 7) made of a zinc-based alloy (containing zinc, aluminum, and copper as its main components) with a diameter of 5 mm and a thickness of 1 mm was placed on top of a 3 mm diameter hole drilled in the center of a black polystyrene sheet.

[0251] The discharge electrode was then brought close to the conductive material in the center from above, brought into contact with the conductive material, and then quickly removed. At this time, a spark discharge was observed with the naked eye when the distance between the electrode and the black polystyrene sheet was about 5 to 10 mm, and a sound that seemed to be discharge was also observed.

[0252] The discharged samples were neutralized in the same manner as in Experiment 201 and then treated.

[0253] "Experiment 204" In Experiment 201, instead of the black polystyrene sheet, a disk-shaped button made of ABS resin, 20 mm in diameter and 1.5 mm thick, with two 1.5 mm diameter holes near the center, was used. Four types of disk-shaped buttons were used: a colorless transparent button and transparent buttons colored blue, red, and green. The four types of buttons were arranged on the exposed surface of the mono-sheet laminate so as not to overlap.

[0254] After that, corona discharge was performed in the same manner as in Experiment 201. Next, the discharge electrode was approached from above to the hole near the center of each disk-shaped button, brought into contact with the disk-shaped button, and then quickly removed. At this time, spark discharge was visible to the naked eye when the distance between the electrode and the button was about 2 to 10 mm, and the accompanying sound was observed.

[0255] Spark discharge was performed once on each disc-shaped button. The samples that had been subjected to the discharge were neutralized in the same manner as in Experiment 201, and then treated.

[0256] "Experiment 205" In Experiment 201, cubic polyethylene terephthalate resin pellets with sides of 3 mm were inserted into the four corners of the rectangular black polystyrene sheet, thereby setting the distance between the cover sheet of the mono-sheet laminate and the black polystyrene sheet, which was the sheet-like insulating member, at 3 mm. The corona discharge was performed in the same manner as in Experiment 201. After the corona discharge, the discharge electrode was approached from above to the center of the black polystyrene sheet at a speed of approximately 50 mm per second, brought into contact with the black polystyrene sheet, and then further pressed until the black polystyrene sheet contacted the cover sheet. The electrode was then quickly released. A sound believed to be a discharge was observed during this process. In Experiment 205, the corona discharge and subsequent contact of the black polystyrene sheet with the cover sheet were performed three times. The discharged samples were neutralized in the same manner as in Experiment 201 and then treated.

[0257] "Experiment 206" In Experiment 201, the size of the black polystyrene sheet was changed to a black polystyrene sheet with a matte surface, measuring 70 mm wide x 100 mm long and 0.4 mm thick. This black polystyrene sheet was processed into a box shape with a depth of 5 mm in the height direction, and by covering it with the box, the photosensitive surface of the photosensitive element could be substantially shielded from light. For this mono-sheet laminate sample, the environment for the experimental work was set to 100 lux under white LED light.

[0258] The corona discharge process was carried out in the same manner as in Experiment 201. After the corona discharge, the discharge electrode was brought closer to the center of the black polystyrene sheet from above at a speed of approximately 50 mm per second, brought into contact with the black polystyrene sheet, and then pushed further in until the black polystyrene sheet contacted the cover sheet, after which the electrode was quickly released. At this time, a sound believed to be a discharge was observed. In Experiment 206, the corona discharge process and the subsequent contact of the black polystyrene sheet with the cover sheet were carried out three times. The discharged samples were neutralized in the same manner as in Experiment 201 and then processed.

[0259] "Experiment 207" In Experiment 206, after corona discharge, the discharge electrode was brought into contact with the center of the black polystyrene sheet from above at a speed of about 50 mm per second. Then, the center of the exposed portion of the mono-sheet laminate was brought into contact with the center of the black polystyrene sheet, and then quickly removed. At this time, a sound that seemed to be a discharge was observed.

[0260] In Experiment 207, the process of corona discharge and subsequent contact of the black polystyrene sheet with the cover sheet was performed three times. The discharged samples were neutralized in the same manner as in Experiment 201 and then treated.

[0261] "Experiment 208" Corona discharge was carried out in the same manner as in Experiment 202, except that the distance between the black polystyrene sheet and the cover sheet was 15 mm. The discharge electrode was then brought close to the central gap from above, brought into contact with the black polystyrene sheet, and then quickly removed. A sound believed to be a discharge was heard when the electrode and polystyrene sheet came into contact. The discharged sample was neutralized in the same manner as in Experiment 202, and then processed.

[0262] "Experiment 209" Corona discharge was carried out in the same manner as in Experiment 202, except that the distance between the black polystyrene sheet and the cover sheet was set to 20 mm. The discharge electrode was then brought close to the central gap from above, brought into contact with the black polystyrene sheet, and then quickly removed. A sound believed to be a discharge was heard when the electrode and polystyrene sheet came into contact. The discharged sample was neutralized in the same manner as in Experiment 202, and then processed.

[0263] The discharge images after processing were evaluated as follows.

[0264] (1) Discharge Image When a sheet-like insulating material is colored, the discharge state occurring underneath cannot be visually observed during discharge. Therefore, the exterior of the colored sheet-like insulating material (insulating sheet) was subjected to the evaluations (a) to (d) and (x) similar to those in Example 1, and in addition, the lower part of the colored insulating sheet was evaluated using the evaluations (α) to (ε).

[0265] Evaluation of the outside of the insulating sheet (a) Branched streaks of light resembling lightning were observed in the formed image, giving the impression of a visible discharge.

[0266] (b) A light streak indicating discharge from the breakdown area was observed in the formed image.

[0267] (c) The shape of the breakdown area was observed as a shadow in the formed image.

[0268] (d) In the formed image, a yellow-green to black re-reversed negative image was observed within the white discharge light.

[0269] (x) In the formed image, instead of branch-like streaks of light like lightning, an image was observed in which the surrounding area became bright.

[0270] Evaluation of the bottom of the insulating sheet (α) In the formed image, dendritic streaks of light were observed, resembling lightning.

[0271] (β) In the formed image, branching weak light streaks were observed, indicating discharge from the insulation breakdown area.

[0272] (γ) In the formed image, the shape of the vicinity of the insulation breakdown portion was observed as a shadow.

[0273] (δ) In the formed image, a yellow-green to black re-reversed negative image was observed within the white discharge light.

[0274] (ε) In the formed image, a pale discharge light changed in color according to the color of the sheet-like insulating material.

[0275] At the same time, the shape of the sheet insulation was also recorded.

[0276] (χ) In the formed image, instead of branch-like streaks of light like lightning, an image was observed in which the surrounding area was bright.

[0277] Of these evaluations, (x) and (χ) are undesirable because they are images that are likely to have light fogging or the like.

[0278] The discharge image after processing was evaluated by summarizing the features (a) to (d), (x), (α) to (ε), and (χ) formed in the image in the evaluation column.

[0279] (2) Processing Defects: Evaluation was performed in the same manner as in Example 1.

[0280] The conditions and results of each experiment are shown in Table 3 below.

[0281]

[0282] Table 3 shows that in the embodiment of the present invention in which the sheet-like insulating material is overlaid on the cover sheet, discharge images are observed both outside and underneath the sheet-like insulating material (Experiments 201 to 205, 208).

[0283] Furthermore, when the sheet-like insulating material was transparent and colored, the originally bluish-white photodischarge light was recorded as changing to the color of the sheet-like insulating material, and its shape was also recorded (Experiment 204).

[0284] Furthermore, due to corona discharge from the electrodes of the DC discharge device, blue exposed images were observed in the areas where the colored insulating sheet material did not cover the exposed surface of the photosensitive element (Experiments 201 to 205, 208).

[0285] Furthermore, when the sheet-like insulating material substantially covered the exposed surface of the photosensitive element, a discharge image could be recorded even in a bright room (Experiments 206 and 207).On the other hand, when the distance between the cover sheet and the sheet-like insulating material exceeded 15 mm, only a blurred, fog-like image was obtained, with the entire area around the discharge bright (Experiment 209).

[0286] In addition, by adjusting the relative humidity of the room to 55-60%, lowering the voltage of the Van de Graaff generator to 15-19 kV, and shortening the corona discharge time, it was possible to adjust the conditions so as to reduce the frequency of re-inverted negative images.

[0287] Example 3 [Fabrication of mono-sheet laminate and preparation for discharge] A mono-sheet laminate was fabricated in the same manner as in Example 1. A box capable of housing a cover sheet laminate measuring 60 mm wide x 90 mm long x 4 mm deep was fabricated using black polystyrene resin with a thickness of 2 mm. The bottom of the box was grounded to the outside with aluminum vapor deposition tape.

[0288] The mono-sheet laminate was placed with the exposed surface facing up, and a conductive connecting member (with aluminum vapor deposition) was attached in a frame shape to the outer periphery of the opposite side to the exposed surface. Part of the conductive connecting member was in contact with the aluminum tape for earthing.

[0289] A black polystyrene sheet measuring 60 mm wide x 90 mm long x 0.4 mm thick was prepared as a light-shielding sheet-like insulating material (insulating sheet) and used in the following experiments.

[0290] The voltage of the Van de Graaff type generator was adjusted to a range of 25 kV to 30 kV, similar to that of Example 1. The room temperature was set to 22 to 25°C, and the relative humidity was set to a range of 40 to 50%.

[0291] "Experiment 301" The following metal plate with pins (corresponding to the third conductive material 26 shown in Figure 7) was placed approximately in the center of a black polystyrene sheet measuring 60 mm x 90 mm x 0.4 mm thick. The metal plate with pins was made of a zinc-based alloy.

[0292] Letters were embossed at a height of 0.4 mm on a plate measuring 20 mm wide x 8 mm long x 2.4 mm thick. The letters were called "THUNDER." A 0.8 mm diameter, 7 mm long needle-shaped metal was attached to the back of the plate to ensure electrical continuity. This component is called a metal plate with a pin.

[0293] A hole was drilled in the center of the black polystyrene sheet to accommodate the pin, and the metal plate with the pin was inserted. The metal plate was placed on top of the box containing the mono-sheet laminate, with the lettering facing the box. The black polystyrene sheet and the pin were joined with light-shielding tape to prevent light from leaking.

[0294] The most convex surface of the metal plate and the cover sheet were in substantial contact with each other. The distance between the light-shielding black polystyrene sheet and the cover sheet was approximately 2.4 mm to 3.6 mm. In this way, a light-shielding mono-sheet laminate assembled into a box shape was prepared.

[0295] The mono-sheet laminate assembled into a box shape and shielded from light was handled in a bright room. Corona discharge from the discharge electrode rod of the Van de Graaff generator onto the upper surface of the black polystyrene sheet and approach or contact of the electrode with the metal needle connected inside were performed under the conditions shown in Table 4 below (Experiments 301A to 301E), and the shape of the metal plate and discharge images of the letters were exposed onto the photosensitive element.

[0296] For specimens 301A to 301D, corona discharge was performed for 15 seconds, followed by two discharges to the conductive material on the outer surface. This procedure was repeated four times, and then discharges to the conductive material on the outer surface were performed a predetermined number of times according to the conditions in Table 4 below.

[0297] For 301E, corona discharge was performed for 30 seconds, and then an electrode was brought into contact with the conductive material on the outer surface for 30 seconds. This procedure was repeated three times.

[0298] The mono-sheet laminate sample after discharge was handled in a darkroom. After removing the sheet-like insulating material, it was irradiated with an ionizer for static elimination. The alkaline processing composition was spread between the photosensitive element and the cover sheet to a thickness of 55 μm using a pressure roller. The processing was carried out at 25° C., and the discharge image formed after 10 minutes was observed. The results will be described later together with the discharge conditions, etc.

[0299] "Experiment 302" In Experiment 301, the conductive material was changed. A 3.0 mm thick metal pendant head representing an initial was used as the conductive material. The metal plate had rounded edges with a 1.0 mm R-chamfer. The letter was "K." When viewed from above, the size of the pendant head was such that it would fit within a circle with a diameter of 12 mm.

[0300] Conduction of the light-shielding sheet-like insulating material was achieved by drilling a 5 mm diameter hole in the insulating material, sealing the hole with aluminum vapor deposition tape, and then attaching a pendant head to that area. The hole portion sealed with aluminum vapor deposition tape on the side not in contact with the photosensitive material was covered with light-shielding tape to prevent external light from entering. The exposed aluminum vapor deposition tape on the exterior surface was used to ensure electrical continuity with the interior.

[0301] The most convex surface of the pendant head and the cover sheet were substantially in contact with each other, but the distance between the chamfered portion was about 1.0 mm. The distance between the black polystyrene sheet and the cover sheet was approximately between 3.0 mm and 3.6 mm.

[0302] The mono-sheet laminate after shading was handled in a bright room. Corona discharge from the discharge electrode of the Van de Graaff generator onto the top surface of the black polystyrene sheet and proximity or contact with the aluminum vapor-deposited tape inside were performed under the conditions (302A to 302E) shown in Table 4, and the shape of the pendant head was exposed to the photosensitive element. The conditions for corona discharge and discharge or contact with the conductive material on the outer surface were the same as those for 301A to 301E.

[0303] The mono-sheet laminate sample after the discharge was handled in a dark room. After discharging in the same manner as in Experiments 301A to 301E, the sample was developed and the discharge image was observed.

[0304] The conditions and results of each experiment are shown in Table 4 below.

[0305]

[0306] Table 4 shows that, whether the conductive material is integrated with the photosensitive element on the outer surface or connected by a detachable material, by discharging the conductive material on the insulating sheet, a discharge image that reflects the shape of the conductive material facing the photosensitive element can be obtained (Experiments 301A to 301D, 302A to 302D).

[0307] It was also found that even when an electrode was brought into contact with the conductive material on the insulating sheet, a discharge image that replicated the shape of the conductive material on the photosensitive element side could be obtained (Experiments 301E and 302E).

[0308] Example 4 Images were recorded during discharge in the same manner as in Experiments 101, 106, and 110 of Example 1, Experiments 201 to 207 of Example 2, and Experiments 301B, 301C, 302B, and 303C of Example 3, except that the following members were additionally installed on the upper side of the cover sheet of the mono-sheet laminate.

[0309] When the obtained discharge images were examined, it was found that the external shape of the installed components was recorded, the color of the discharge light was changed, and the direction of the discharge light was changed.

[0310] [Installed items] (1) Transparent acrylic resin items: Plate-shaped, spherical, rod-shaped. Items colored yellow, orange, red, and green, approximately 2 mm thick. (2) Opaque ABS resin items: Plate-shaped. Letters and icons. Items colored black, approximately 2 mm thick. (3) Colored glass: Items colored in a single color or multiple colors, approximately 3 mm thick.

[0311] Example 5 In Experiment 106 of Example 1, 10 unexposed mono-sheet laminates were prepared, and for each mono-sheet laminate, the position of the conductive material was arbitrarily changed on the cover sheet, and discharge was performed only once from the electrode to prepare 10 discharge-exposed mono-sheet laminates. After static elimination in the same manner as in Example 1, the mono-sheet laminates were packed into plastic film packs shielded from light by carbon black.

[0312] The container was then placed in a light-shielding plastic film bag coated with aluminum to prepare a storage pack.

[0313] Mono-sheet laminate size: 54 mm wide, 86 mm long, of which the image forming surface size is 46 mm wide, 62 mm long. Film pack size: 58 mm wide, 90 mm long, thickness 19 mm.

[0314] In Experiment 202 of Example 2, ten unexposed mono-sheet laminates were prepared, and the position of a black polystyrene sheet with a hole in the center placed on top of the cover sheet was changed to any position on the top of the cover sheet for each mono-sheet laminate, and discharge was performed only once from the electrode to prepare ten exposed mono-sheet laminates.

[0315] After static elimination in the same manner as in Example 1, the mixture was packed into a plastic film pack shielded from light by carbon black, and then housed in a plastic film bag shielded from light by vapor deposition of aluminum to prepare a storage pack.

[0316] In Experiment 301C of Example 3, 10 unexposed mono-sheet laminates were prepared and subjected to discharge exposure under the same conditions to produce 10 discharge-exposed mono-sheet laminates. After static elimination in the same manner as in Example 1, the laminates were packed into a plastic film pack shielded from light by carbon black. The laminates were then housed in a plastic film bag shielded from light by vapor deposition of aluminum to produce a storage pack.

[0317] The mono-sheet laminate storage pack prepared as described above was attached to an electronic still camera with a built-in printer having an array of three-color organic EL light-emitting elements, as described in Japanese Patent No. 3818564. Various subjects, from bright to dark, were freely photographed using the electronic still camera, and the photographed images were exposed to the mono-sheet laminate, and a processing solution was applied to form an image. The exposure by this camera corresponded to exposure to visible light in the B, G, and R light regions. The image formed after processing recorded both the information exposed by discharge (discharge image) and the subject image photographed by the camera. Furthermore, since the discharge-exposed area partially formed an image up to the re-reversal negative area, the discharge image was recorded without fading even when the subject image photographed by the camera was bright.

[0318] DESCRIPTION OF SYMBOLS 1...Transparent support 2...Image receiving element 3...Silver halide photographic light-sensitive element (light-sensitive element) 4...Cover sheet 5...Spacer 6...Conductive connecting member 10...Mono-sheet laminate 10a...Image surface 12...Exposure section 14...Pod 14a...Alkaline processing liquid 16...Trap section 16a...Absorbing material 22...First conductive material 24...Sheet-like insulating material 26...Third conductive material 26a...Conducting section 30...DC discharge device 32...Discharge electrode rod 32a...Electrode

Claims

1. A method for forming an image on a mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding attached to the periphery of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, the method comprising: discharging electricity onto the mono-sheet laminate from an electrode of a direct current discharge device positioned at a distance of 0 mm to 15 mm from the surface of the cover sheet in the normal direction to the surface; and spreading the alkaline processing liquid contained in the pod between the silver halide photographic light-sensitive element and the cover sheet to form a discharge image.

2. A method for forming an image on a mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding attached to the periphery of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, the method comprising the steps of: placing a first conductive material at a distance of 0 mm to 10 mm from the surface of the cover sheet in the normal direction to the surface; discharging from an electrode of a direct current discharge device to the first conductive material; and spreading the alkaline processing liquid contained in the pod between the silver halide photographic light-sensitive element and the cover sheet to form a discharge image.

3. An image forming method for forming an image on a mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding joined to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, the image forming method comprising the steps of: placing a sheet-like insulating material at a distance of 0 mm to 15 mm from the surface of the cover sheet in a normal direction to the surface; subjecting the sheet-like insulating material to corona discharge from an electrode of a direct current discharge device to charge the sheet-like insulating material with static electricity; causing a dielectric breakdown at at least one point on the statically charged sheet-like insulating material to discharge the charged static electricity; and spreading the alkaline processing liquid contained in the pod between the silver halide photographic light-sensitive element and the cover sheet to form a discharge image.

4. The image forming method according to claim 3, wherein the sheet-like insulating material has a void penetrating through at least a portion of the sheet-like insulating material in the thickness direction, and dielectric breakdown occurs when an electrode of the DC discharge device is brought close to the void.

5. The image forming method according to claim 3 or 4, wherein the sheet-like insulating material has a second conductive material disposed at at least one point on the surface of the sheet-like insulating material, and dielectric breakdown occurs when discharge occurs from the electrode of the DC discharge device to the second conductive material.

6. The image forming method according to claim 3, wherein the sheet-like insulating material is placed at a distance of 1 mm to 15 mm from the surface of the cover sheet in the normal direction of the surface, and the distance between the charged sheet-like insulating material and the mono-sheet laminate is partially shortened, causing a dielectric breakdown at at least one point on the sheet-like insulating material.

7. The image forming method according to claim 3, 4 or 6, wherein said sheet-like insulating material absorbs at least a portion of light of wavelengths in the photosensitive region of said silver halide photographic light-sensitive element.

8. The image forming method according to claim 3, 4 or 6, wherein said sheet-like insulating material does not transmit light of wavelengths in the photosensitive region of said silver halide photographic light-sensitive element.

9. The image forming method according to claim 3, 4 or 6, wherein said sheet-like insulating material does not transmit light of wavelengths in the photosensitive region of said silver halide photographic light-sensitive element and shields the exposed surface of said silver halide photographic light-sensitive element from light.

10. A method for forming an image on a mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding joined to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, the method comprising: placing a sheet-like insulating material that blocks at least a portion of wavelengths in the visible light region on the upper side of the cover sheet; placing a third conductive material in contact with or close to the cover sheet on the inner surface of the sheet-like insulating material facing the cover sheet; providing a conductive part that is electrically conductive with the third conductive material, a part of the conductive part being exposed on the outer surface of the sheet-like insulating material; bringing an electrode of a DC discharge device into contact with or close to a part of the exposed conductive part, and discharging from the electrode to the third conductive material via the conductive part; an image forming method, wherein the alkaline processing liquid contained in the pod is spread between the silver halide photographic light-sensitive element and the cover sheet to form a discharge image including an image showing the shape of the third conductive material.

11. The image forming method according to claim 10, wherein the conductive portion electrically conducting with the third conductive material is integrated with the third conductive material, penetrates the sheet-like insulating material, and is exposed on the outer surface side of the sheet-like insulating material.

12. The image forming method of claim 10, wherein the conductive portion electrically conducting with the third conductive material is a member that is detachable from the third conductive material, and when attached to the third conductive material, a portion of the conductive portion is exposed on the outer surface of the sheet-like insulating material.

13. The image forming method according to any one of claims 10 to 12, wherein the sheet-like insulating material covers the entire exposed surface of the silver halide photographic light-sensitive element.

14. An image forming method according to any one of claims 10 to 12, wherein the sheet-like insulating material does not transmit at least a portion of wavelengths in the visible light region, and an electrode of the DC discharge device is brought into contact with or close to the conductive portion of the third conductive material under light of the wavelengths in the visible light region that are not transmitted, and discharge is caused from the electrode to the third conductive material via the conductive portion.

15. The image forming method according to any one of claims 1 to 4, 6, and 10 to 12, wherein an element that changes the absorption, scattering, or reflection of light is provided on the upper side of the cover sheet.

16. The image forming method according to any one of claims 1 to 4, 6, and 10 to 12, wherein the discharge image is formed with a color density corresponding to the exposure intensity of the positive and negative areas of the silver halide photographic light-sensitive element.

17. The image forming method according to any one of claims 1 to 4, 6, and 10 to 12, further comprising a step of exposing to visible light in addition to the exposure by discharge.

18. A mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding bonded to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, wherein the mono-sheet laminate has been subjected to at least one discharge exposure by the image-forming method described in any one of claims 1 to 4, 6, and 10 to 12, and has not been subjected to development processing with the alkaline processing liquid contained in the pod.

19. The mono-sheet laminate according to claim 18, wherein the mono-sheet laminate is set in a camera or printer, and exposed to light in a direct positive area at least once by the camera or printer, followed by development processing.

20. A mono-sheet laminate comprising a transparent support on which an image-receiving element and an autopositive type silver halide photographic light-sensitive element are laminated, a cover sheet covering the silver halide photographic light-sensitive element, a conductive connecting member for grounding attached to the peripheral portion of the surface of the transparent support opposite to the surface on which the image-receiving element is laminated, and a pod containing an alkaline processing liquid, wherein the mono-sheet laminate has been subjected to at least one exposure by discharge and at least one exposure by visible light by the image-forming method described in any one of claims 1 to 4, 6, and 10 to 12, and has not been subjected to development processing with the alkaline processing liquid contained in the pod.

21. The mono-sheet laminate according to claim 20, wherein the mono-sheet laminate is set in a camera or a printer and subjected to a development process without being exposed by the camera or the printer.

Images