Double-sided electrostatic printing method

Abstract

To enable both patterns to be formed on both sides of an image-receiving sheet as accurate as a design value.SOLUTION: An original plate A comprises an electrode 21 having wholly uniform conductivity, and a plate layer 22. A mask sheet M comprises a molded body only composed of conductive material or a laminated body composed of insulative material and conductive material. An image-receiving sheet 10 comprises a conductive layer as an electrode 11 and image-receiving layers laminated on both sides of the conductive layer. One image-receiving layer of the image-receiving sheet is brought into close contact with either the plate layer or the mask sheet of the original plate while the other image-receiving layer of the image-receiving sheet is brought into close contact with either the plate layer or the mask sheet of the original plate. Both sides of the image-receiving sheet are subjected to discharge ion generation by application of voltage between the electrode of the original plate and the electrode of the image-receiving sheet or ion irradiation through the mask sheet, so that electrostatic patterns are formed on image-receiving layers on both sides of the image receiving sheet.SELECTED DRAWING: Figure 3(2)

Description

Technical Field

[0001] The present invention relates to a method for forming an electrostatic pattern on the image receiving layers on both sides of an image receiving sheet by generating discharge ions by applying a voltage between the electrodes of the original plate and the electrodes of the image receiving sheet on both sides of the image receiving sheet or by irradiating ions through a mask sheet. The principle is related to discharge technology, and the use of electrostatic printing is related to the electrostatic printer technology represented by electrophotography.

Background Art

[0002] The first person in the world to invent a practical technology for creating images using static electricity was Chester Carlson of the United States. The technology related to this invention was commonly called the Carlson method or the Xerography method. However, academic research on it as an image forming technology progressed, and it was called Electrophotography as an academic name, and was named the electrophotography method in Japan. Copiers and printers made using that technology have become essential for office work.

[0003] As the technology was named "photography", an optical image is formed as an electrostatic latent image by static electricity and a photoreceptor (optical semiconductor), and developed with charged fine particles called toner. As a copier that immediately prints and outputs an image that changes for each page onto paper, it has developed as an excellent technology. Among its developments, the most evolved are the toner, which is a developer, and the developing technology. The powder toner has been made into fine particles up to about 6 μm, and at the same time, uniform particle diameter and uniform charging have been realized to improve the resolution and transfer stability. Furthermore, the further micronized liquid toner has a submicron size, and the stability of the developer can also be ensured, and it has even become superior to printing ink in terms of resolution. Furthermore, not only as a color toner, but also toners containing metals, methods of developing with metals themselves, toners capable of plating as in Patent Document 2, etc., functional toners and developing methods have been continuously developed regardless of whether they are powder or liquid.

[0004] However, electrophotography has limitations in fully utilizing the characteristics of these functional toners. This is due to the fundamental element of creating an electrostatic pattern on the photoreceptor. In other words, the electrostatic pattern on the photoreceptor must be developed, and the developed toner must be transferred to the target material. Of course, this method is what enables plateless, high-resolution, and high-speed printing, but the resolution inevitably decreases with transfer, and conductive toner cannot be transferred except by adhesive. Furthermore, current photoreceptors have analog characteristics, making it difficult to accurately print 10μm dots or lines and dots or lines of 100μm or larger simultaneously at high speed. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-19272 [Patent Document 2] Japanese Patent Publication No. 2007-134422 [Non-patent literature]

[0006] [Non-Patent Document 1] Seino, Tanaka, Inoue, Tajima: Journal of the Institute of Electronic Photography, Vol. 7, No. 1, p. 2. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Various attempts have been made in the past to directly develop electrostatic patterns. One such attempt, as shown in Non-Patent Document 1, is an electrostatic transfer system that directly develops the electrostatic pattern itself by transferring it from a photoreceptor. However, due to the special nature of the transfer paper and the principle that the electrostatic pattern is created by peeling discharge, the resolution is lower than that of patterns on a photoreceptor, and it is no longer manufactured. Devices that directly draw electrostatic patterns, such as multi-styluses and methods that deflect ion beams, have been commercialized, but due to limitations in electrode processing precision and low resolution caused by the spread of discharge ions, they have been replaced by inkjet methods. Furthermore, although it is a method for forming electrostatic patterns for electrostatic actuators, Patent Document 1 proposes obtaining fidelity of the electrostatic pattern to the electrodes by providing a partition around the electrodes and limiting the discharge range. However, the method in Patent Document 1 cannot create image patterns like those produced by printing or electrophotography. Combining high-definition electrostatic patterns with continuously evolving toners opens up the possibility of printing with unprecedented effects and performance, and there is a growing demand for methods to directly create high-definition electrostatic patterns on insulators other than photoreceptors.

[0008] Therefore, the inventors proposed a practical high-definition electrostatic printing method that uses static electricity to create images without using a photoreceptor, and that is comparable to, or even surpasses, conventional printing (see Japanese Patent Application No. 2018-188998). According to one aspect of the above invention, a high-definition electrostatic printing method is provided, characterized in that a master plate is composed of a first electrode having uniform conductivity throughout its entire surface and a plate layer made of a material that is in close contact with and integrally formed on the first electrode and has an appropriate uniform thickness, and a relief plate, recessed plate, or gravure plate-like pattern is formed on the plate layer, and an image receiving sheet is brought into close contact with the master plate, which has a conductive layer integrated on its back surface that is a second electrode, and an appropriate voltage sufficient to discharge the voids in the relief plate, recessed plate, or gravure plate-like pattern is applied between the first electrode of the master plate and the second electrode of the image receiving sheet, thereby forming an electrostatic pattern on the image receiving sheet that corresponds to the relief plate, recessed plate, or gravure plate-like pattern.

[0009] The electrostatic pattern on the image receiving sheet becomes a visible pattern when developed with charged particles. If the charged particles are plateable, a high-resolution electrode circuit pattern is formed on the image receiving sheet by performing a plating process after development with the charged particles. However, the above invention had the following problems. In application fields of electronic components and the like that utilize electrode circuit patterns, X electrode circuit patterns and Y electrode circuit patterns are often bonded together using an adhesive layer or the like, and both patterns are used as a set. However, in the above invention, since the two patterns are processed separately from the electrostatic pattern to the electrode circuit pattern, differences in the process history, such as moisture absorption and drying, can cause differences in the dimensional changes of the electrode circuit pattern relative to the electrostatic pattern. Furthermore, there are limitations to the alignment accuracy when bonding the two patterns together. As a result, the positional relationship between the two patterns does not meet the design specifications, making it difficult to manufacture electronic components and the like that satisfy quality requirements. This invention proposes a double-sided electrostatic printing method that solves the above problems. [Means for solving the problem]

[0010] According to a first aspect of the present invention, the original plate A is composed of a second electrode having uniform conductivity across its entire surface and a plate layer made of an electrically insulating, conductive, or semiconductive material that is in close contact and integral with the second electrode and has an appropriate uniform thickness, and a relief, recessed, or gravure plate-like pattern is formed on the plate layer. The original plate B is composed of a third electrode having uniform conductivity across its entire surface and a plate layer made of an electrically insulating, conductive, or semiconductive material that is in close contact and integral with the third electrode and has an appropriate uniform thickness, and a relief, recessed, or gravure plate-like pattern is formed on the plate layer. The image receiving sheet is composed of a conductive layer which is the first electrode and an image receiving layer laminated on both sides of the conductive layer. The original plate A and the original plate B are placed with a gap between them so that their respective plate layers face each other, and the image receiving sheet is placed between the original plate A and the original plate B. A double-sided electrostatic printing method is provided, characterized by bringing the plate layer of the original plate A and the image receiving layer of the image receiving sheet on the original plate A side, and the plate layer of the original plate B and the image receiving layer of the image receiving sheet on the original plate B side, and applying an appropriate voltage sufficient to discharge the gaps in the relief, recessed, or gravure plate-like patterns of the plate layers of the original plate A and the original plate B between the second electrode of the original plate A and the first electrode of the image receiving sheet and between the third electrode of the original plate B and the first electrode of the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer on one side of the image receiving sheet corresponding to the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate A, and an electrostatic pattern on the image receiving layer on the opposite side of the image receiving sheet corresponding to the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate B.

[0011] According to a second aspect of the present invention, the mask sheet M consists of a molded body made solely of a conductive material or a laminate of an insulating material and a conductive material, and is provided with a predetermined ion-permeable opening. The mask sheet L consists of a molded body made solely of a conductive material or a laminate of an insulating material and a conductive material, and is provided with a predetermined ion-permeable opening. The image receiving sheet consists of a conductive layer which is a first electrode and an image receiving layer laminated on both sides of the conductive layer. A double-sided electrostatic printing method is provided, characterized in that the mask sheet M and the mask sheet L are placed facing each other with a gap between them, and the image receiving sheet is placed between the mask sheet M and the mask sheet L. The image receiving layer on the mask sheet M side of the image receiving sheet and the image receiving layer on the mask sheet L side of the image receiving sheet are brought into close contact with the mask sheet M and the image receiving layer on the mask sheet L side of the image receiving sheet, and after ion irradiation is performed through the mask sheet M and the mask sheet L, the mask sheet M and the mask sheet L are separated from the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer on one side of the image receiving sheet corresponding to the ion permeable opening of the mask sheet M, and an electrostatic pattern on the image receiving layer on the opposite side of the image receiving sheet corresponding to the ion permeable opening of the mask sheet L.

[0012] According to a third aspect of the present invention, the original plate A and the mask sheet M are arranged with a gap between them such that the plate layer of the original plate A and the mask sheet M face each other, and the image receiving sheet is placed between the original plate A and the mask sheet M. The plate layer of the original plate A and the image receiving layer of the image receiving sheet on the original plate A side, and the mask sheet M and the image receiving layer of the image receiving sheet on the mask sheet M side are brought into close contact. An appropriate voltage sufficient to discharge the gaps in the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate A is applied between the second electrode of the original plate A and the first electrode of the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer of the image receiving sheet on the original plate A side corresponding to the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate A. Furthermore, after ion irradiation through the mask sheet M, the mask sheet M is separated from the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer of the image receiving sheet on the mask sheet M side corresponding to the ion-permeable opening of the mask sheet M. A double-sided electrostatic printing method is provided, characterized by generating discharge ions by applying a voltage between the electrodes of the original plate and the electrodes of the image receiving sheet on one side of the image receiving sheet, and irradiating the opposite side of the image receiving sheet with ions through a mask sheet, thereby forming an electrostatic pattern on the image receiving layer on both sides of the image receiving sheet. According to the first to third aspects of the present invention, the electrostatic pattern formed on the image-receiving layer on both sides of the image-receiving sheet becomes a visible pattern when developed with charged particles. If the charged particles are plateable particles, an electrode circuit pattern is formed as a set on the image-receiving layer on both sides of the image-receiving sheet by performing a plating treatment after development with the charged particles.

[0013] The configuration of the first aspect of the present invention and the process of electrostatic pattern formation will be explained using the basic conceptual diagram in Figure 1 for easier understanding. Figure 1(1) shows the configurations of the original plate A, the original plate B, and the image receiving sheet 10. Original plate A consists of an electrode 21 and a plate layer 22 in the form of a relief, recessed, or gravure plate, and original plate B consists of an electrode 31 and a plate layer 32 in the form of a relief, recessed, or gravure plate. The image receiving sheet 10 consists of an electrode 11 and image receiving layers 12 and 13 laminated on both sides of the electrode 11. If necessary, an intermediate layer 14 is provided between the electrode 11 and the image receiving layer 12, and / or between the electrode 11 and the image receiving layer 13, thereby closely integrating the image receiving layer 12, the electrode 11, and the image receiving layer 13. The original plate A and the original plate B are placed with a gap between them so that their respective plate layers face each other, and the image receiving sheet is placed between the original plate A and the original plate B. Figure 1(2) shows the process of applying voltage with original plates A and B in close contact on both sides of the image receiving sheet. Specifically, first, the plate layer 22 of original plate A and the image receiving layer 12 of the image receiving sheet 10 are brought into close contact, and the plate layer 32 of original plate B and the image receiving layer 13 of the image receiving sheet 10 are brought into close contact. Next, the electrodes 11 of the image receiving sheet 10 are set to ground potential, and a DC voltage is applied between the electrodes 21 of original plate A and the electrodes 11 of the image receiving sheet 10, and between the electrodes 31 of original plate B and the electrodes 11 of the image receiving sheet 10. This discharges the gas in the voids 22a and 22b of the recesses of plate layer 22, and the gas in the voids 32a and 32b of the recesses of plate layer 32, thereby depositing ionized ions on the image receiving layer 12 and the image receiving layer 13. Figure 1(3) shows that after grounding the electrodes 21 of original plate A and 31 of original plate B, the image receiving sheet 10 is separated from original plate A and original plate B, thereby forming electrostatic patterns P1 to P4 on the image receiving layer 12 corresponding to the voids 22a and voids 22b of the recessed plate layer 22, and electrostatic patterns P5 to P8 on the image receiving layer 13 corresponding to the voids 32b and voids 32a of the recessed plate layer 32.

[0014] The configuration of the second aspect of the present invention and the process of forming the electrostatic pattern will be explained using the basic conceptual diagram in Figure 2 for easier understanding. The image receiving sheet 10 shown in Figure 2(1) has the same configuration as the one described in the first aspect of the present invention. The electrodes 11 of the image receiving sheet 10 are grounded. Before the mask sheets M and L are brought into close contact with the image receiving sheet 10, both sides of the image receiving sheet 10 are pre-charged with a charge of opposite polarity to the charge used to form the electrostatic pattern (in this example, +300V). This charging process ensures that the mask sheets M and L adhere securely to the image receiving sheet 10. Figure 2(2) shows the process of ion irradiation being performed through the mask sheet M and the mask sheet L, respectively, by the ion irradiation means 40 and the ion irradiation means 50, with the mask sheet M and the image receiving layer 13, and the mask sheet L and the image receiving layer 12 in close contact. After ion irradiation, the surface of the mask sheet M, the portion of the image receiving layer 13 corresponding to the ion-permeable opening M1, and the surface of the mask sheet L, the portion of the image receiving layer 12 corresponding to the ion-permeable opening L1, become charged (-300V in this example). Figure 2(3) shows the state after separation of the mask sheet M and mask sheet L from the image receiving sheet 10 with the mask sheet M and mask sheet L grounded. An electrostatic pattern P9 is formed on the image receiving layer 13 of the image receiving sheet 10, and an electrostatic pattern P10 is formed on the image receiving layer 12. The parts that were shielded by the mask sheet M and mask sheet L during ion irradiation are charged to +300V.

[0015] To facilitate understanding of the configuration and electrostatic pattern formation process of the third aspect of the present invention, a basic conceptual diagram will be used in Figure 3. The image receiving sheet 10 shown in Figure 3(1) has the same configuration as that described in the first aspect of the present invention. The electrodes 11 of the image receiving sheet 10 are grounded. Before the original plate A and mask sheet M are brought into close contact with the image receiving sheet 10, both sides of the image receiving sheet 10 are pre-charged with a charge of opposite polarity to the charge used to form the electrostatic pattern (in this example, +300V). This charging process ensures that the original plate A and mask sheet M are securely in contact with the image receiving sheet 10. Figure 3(2) shows the process of applying a voltage between the electrode 21 of the original plate A and the image receiving layer 12 of the image receiving sheet, and between the mask sheet M and the image receiving layer 13 of the image receiving sheet, with the plate layer 22 of the original plate A and the image receiving layer 12 of the image receiving layer 12 in close contact. On the other hand, on the image receiving layer 13 side, ion irradiation is performed through the mask sheet M by the ion irradiation means 40. Specifically, on the image receiving layer 12 side, the electrode 11 of the image receiving sheet 10 is set to ground potential, and an appropriate voltage sufficient to discharge the gaps in the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate A is applied between the electrode 21 of the original plate A and the electrode 11 of the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer 12 corresponding to the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate A. On the other hand, on the image receiving layer 13 side, after ion irradiation, the surface of the mask sheet M and the portion corresponding to the ion-permeable opening M1 of the image receiving layer 13 become charged (in this example, -300V). Figure 3(3) shows that after grounding the electrodes 21 of the original plate A, separating the image receiving sheet 10 from the original plate A forms electrostatic patterns P12 to P15 on the image receiving layer 12 corresponding to the voids 22a and voids 22b in the recesses of the plate layer 22. On the other hand, separating the mask sheet M from the image receiving sheet 10 while it is grounded shows that an electrostatic pattern P11 is formed on the image receiving layer 13. [Effects of the Invention]

[0016] The basis of the present invention is not to use peeling discharge, but rather to form an electrostatic pattern (1) created by discharge ions generated in a gap by applying a voltage between the electrode of the original plate and the electrode of the image receiving sheet, or (2) created by ions passing through the ion-permeable openings of the mask sheet. Therefore, an electrostatic pattern without the spread of charged ions can be formed on the image receiving layers on both sides of the image receiving sheet. Comparing the two, in the case of (1), the resolution can be controlled by changing the width of the gap, and by changing the depth of the gap, electrostatic patterns with different amounts of charge can be obtained. It is suitable for forming high-definition electrostatic patterns. In the case of (2), since the mask sheet is easier to manufacture than the original plate, it is suitable for meeting individual requirements such as additional modification of the electrostatic pattern. The electrostatic pattern on the image receiving layers on both sides of the image receiving sheet becomes a visible pattern by being developed with charged particles. When the charged particles are electroplatable particles, after development with the charged particles, an electrode circuit pattern is formed in a set manner on the image receiving layers on both sides of the image receiving sheet by performing an electroplating process. Since the positional relationship between the electrode circuit patterns on the image receiving layers on both sides of the image receiving sheet is accurate to the design value, not only can electronic components etc. that satisfy quality requirements be manufactured using this, but also the thinning of electronic components etc. becomes possible.

Brief Description of the Drawings

[0017] [Figure 1(1)] Original plate arrangement on both sides of the image receiving sheet [Figure 1(2)] Original plate closely adhered to both sides of the image receiving sheet, voltage applied [Figure 1(3)] Separation of the original plate from the image receiving sheet, formation of electrostatic pattern [Figure 2(1)] Preliminary charging treatment on both sides of the image receiving sheet [Figure 2(2)] Mask sheet closely adhered to both sides of the image receiving sheet, ion irradiation through the mask sheet [Figure 2(3)] Separation of the mask sheet from the image receiving sheet, formation of electrostatic pattern [Figure 3(1)] Preliminary charging treatment on both sides of the image receiving sheet [Figure 3(2)]The original image is placed in close contact with one side of the image receiving sheet, and voltage is applied. A mask sheet is placed in close contact with the opposite side of the image receiving sheet, and ion irradiation is performed through the mask sheet. [Figure 3(3)] Separation of the original plate and mask sheet from the image receiving sheet, electrostatic pattern formation. [Figure 4] Paschen curve [Modes for carrying out the invention]

[0018] The configuration in which the original plate is placed on both sides of the image receiving sheet and the electrostatic pattern formation process in this invention are shown in Figure 1. The image receiving sheet 10 is composed of an electrode 11 and two image receiving layers 12 and 13 laminated on both sides of the electrode 11. By providing an intermediate layer 14 between the electrode 11 and the image receiving layer 12, and / or between the electrode 11 and the image receiving layer 13 as needed, the image receiving layer 12, the electrode 11, and the image receiving layer 13 are tightly integrated. The electrode 11 needs to be conductive in order to supply an electric field. Examples of conductive materials include metals, conductive oxides, carbon, graphite, and conductive polymers. The conductive material is appropriately selected depending on whether transparency is required in the application of the image receiving sheet. In applications where transparency is required, one possible configuration is to first provide a transparent conductive layer such as a conductive oxide film or a conductive polymer film as the electrode 11 on the image receiving layer 12, and then laminate the image receiving layer 13 on the transparent conductive layer using an intermediate layer 14 (adhesive layer, bonding layer, etc.). On the other hand, in applications where transparency is not required, one possible configuration is to laminate the image receiving layer 12 and image receiving layer 13 on both sides of the electrode 11, such as a metal foil, using an intermediate layer 14 (adhesive layer, bonding layer, etc.). Alternatively, one possible configuration is to first provide a metal film or the like as the electrode 11 on the image receiving layer 12, and then laminate the image receiving layer 13 on the metal film or the like using an intermediate layer 14 (adhesive layer, bonding layer, etc.).

[0019] The image receiving layer 12 and image receiving layer 13 need to retain static electricity and therefore require high electrical insulation properties. Films such as polyimide, polycarbonate, PET (polyethylene terephthalate), cycloolefin polymer, cycloolefin copolymer, and fluororesin can be used as the image receiving layer 12 and image receiving layer 13. The image receiving layer 12 and image receiving layer 13 do not necessarily have to be made of the same material or have the same thickness. The thickness of the image receiving layer 12 and image receiving layer 13 is preferably 5 to 125 μm. If the thickness is less than 5 μm, handling becomes difficult. Also, if the thickness exceeds 125 μm, it becomes disadvantageous in terms of thinning electronic components, etc. Furthermore, depending on the intended use, it is necessary to consider the relative permittivity of the image receiving layer 12 and the image receiving layer 13, as well as the applied voltage during electrostatic pattern formation.

[0020] Original plate A consists of electrode 21 and plate layer 22, while original plate B consists of electrode 31 and plate layer 32. Electrodes 21 and 31, and plate layers 22 and 32 do not necessarily have to be made of the same material or have the same thickness. Electrodes 21 and 31 only need to have the conductivity necessary for discharge in the gaps 22a (and 22b) and 32a (and 32b), respectively. Depending on the system's process speed, it is acceptable for both electrodes to have a resistivity of 10⁶ Ωcm or less, and even better if it is 10⁴ Ωcm or less. Both electrodes can be made of any conductive material, such as metal, conductive oxide, carbon, graphite, or conductive polymer. Alternatively, they can be made by sputtering a metal film or conductive oxide film onto the surface of glass or plastic, or by coating them with a conductive polymer film. Functionally, there is no problem with applying a treatment layer to the electrode surface of both electrodes to improve adhesion to the plate layer or to prevent deterioration of the electrodes themselves over time.

[0021] The materials for plate layer 22 and plate layer 32 may be conductors, semiconductors, or insulators. When both plate layers are insulators, generally, a photoresist can be coated onto the surface of the substrate (here, electrode 21 and / or electrode 31), or a dry film photoresist can be attached, exposed to ultraviolet light through a pattern mask, and then developed. The remaining photoresist material can then be used as plate layer 22 (and / or plate layer 32). When both plate layers are conductors or semiconductors, the conductive or semiconductor substrate can be engraved with an etching solution, and that portion can be used as plate layer 22 (and / or plate layer 32). In laser processing of metallic copper or electroforming manufacturing methods, the plate layer and electrode become one, but this is not a problem.

[0022] Both plate layers have limitations in terms of the width and depth of the engraving, depending on the plate material and processing method. The minimum depth is limited by the amount of discharge ions generated in the voids. Currently, it seems that around 3 μm is the limit given the toner's developing capabilities, but this may change in the future if toners that can develop sufficiently with a small amount of charge are developed.

[0023] To improve the durability of both master plates, it would be effective to apply a coating to the surface of each electrode or to apply a coating to the entire master plate, and there would be no problems in terms of electrostatic properties.

[0024] Since the electrostatic pattern is formed by the discharge charge in the gaps between the original plate and the image receiving sheet, specifically in gap 22a (and gap 22b) and gap 32a (and gap 32b), the basic principle is to configure the recessed parts of the plate as the target pattern. However, because the electrostatic pattern becomes apparent when developed with charged particles called toner, it is possible to perform so-called negative-positive development in electrophotography technology, and toner can be attached to the parts corresponding to the raised parts of the plate, so the raised parts can also be used as the target pattern. Furthermore, the amount of discharge in the gaps is determined by the depth of the gaps for the same applied voltage; the shallower the gap, the less discharge there is, and as a result the amount of toner attached is also limited, making it possible to print with an effect similar to conventional gravure printing.

[0025] The conditions under which air gaps discharge can be roughly calculated using Paschen's law. Figure 4 shows the Paschen curve for air at atmospheric pressure, with the horizontal axis representing the air gap distance and the vertical axis representing the air gap discharge initiation voltage. The minimum value of the curve is around an air gap distance of approximately 5 μm, and the air gap discharge initiation voltage for air gap distances of 8 μm or more is said to be represented by a linear curve, and is approximated by the following equation, where the air gap distance is d (μm) and the air gap discharge initiation voltage is Vb (V). Vb = 312 + 6.2d (1) If the gap distance is 20 μm, the gap discharge initiation voltage will be 436 V. In other words, when an external voltage of 436 V or higher is applied to the gap, a discharge occurs and ions are generated. The generated ions move according to the electric field; positive ions move towards the negative electrode, and negative ions move towards the positive electrode. The image receiving layer 12 (and image receiving layer 13) becomes charged by the ions, and acts to weaken the electric field in the gap. The discharge ends when the voltage applied to the gap reaches the gap discharge initiation voltage of 436 V.

[0026] An example of intaglio printing is described. In Figure 1(1), the image receiving layer 12 is made of PET with a thickness of 50 μm, the image receiving layer 13 is made of PET with a thickness of 25 μm, and the intermediate layer 14 is made of acrylic adhesive with a thickness of 25 μm. Original plate A (and original plate B) are intaglio plates, with a plate layer 22 thickness and a recessed void 22a depth (and plate layer 32 thickness and recessed void 32a depth) of 20 μm. Assume that the electrode 11 of the image receiving sheet 10 is at ground potential, and that a voltage of -1300 V is applied to the electrode 21 of original plate A (and electrode 31 of original plate B). Assume that the relative permittivity of PET is approximately 3.3 and the relative permittivity of the acrylic adhesive is approximately 3.3. Converting the thickness of 50 μm PET, 25 μm PET, and 25 μm acrylic adhesive to air thickness corresponds to approximately 15.2 μm, 7.6 μm, and 7.6 μm respectively, so the voltage applied to voids 22a and 32a is 1300 × 20 ÷ (20 + 15.2) V = 739 V in both cases. Because the discharge initiation voltage for the 20 μm gap obtained from equation (1) is greater than 436 V, discharge ions are generated in the gap, negative ions move toward electrode 11 and charge the image receiving layer 12 (and image receiving layer 13), and positive ions flow toward electrode 21 (and electrode 31). When the image receiving layer 12 (and image receiving layer 13) is charged to -(739-436)=-303 V, the electric field applied to the gap reaches the discharge initiation voltage of 436 V, and the discharge stops. After that, when the applied power supply is turned OFF and electrode 21 of original plate A (and electrode 31 of original plate B) is grounded, and the image receiving sheet 10 is separated from original plates A and B, an electrostatic pattern is formed on the image receiving layer 12 (and image receiving layer 13) where the portions corresponding to the gaps 22a (and 32a) of each intaglio plate are charged to -303 V. The reason for grounding electrode 21 of original plate A (and electrode 31 of original plate B) before separation is to ensure that no peeling discharge occurs across any part of the entire surface. The electrostatic patterns on the image-receiving layers on both sides of the image-receiving sheet become visible patterns when developed with charged particles. If the charged particles are plateable, electrode circuit patterns are formed on the image-receiving layers on both sides of the image-receiving sheet by performing a plating process after development with the charged particles.

[0027] Original plate A was actually manufactured in the following manner. Electrodes 21 were formed by sputtering an ITO film onto a 2mm thick float glass plate. Next, a dry film resist was attached to the electrodes 21, a touch panel electrode circuit pattern (wiring electrode section L / S=100 / 100, mesh electrode section line width 5μm) mask was placed on top, and after ultraviolet exposure, development was performed to form a plate layer (intaglio) 22 using photoresist, thereby manufacturing original plate A. Original plate B was manufactured in exactly the same manner as original plate A. The image receiving sheet was manufactured in the following manner. Electrodes 11 were formed by coating a conductive polymer (PEDOT / PSS) film onto a 50μm thick PET film, which would become the image receiving layer 12. Next, a 25μm thick intermediate layer 14 (acrylic adhesive layer) was coated onto the electrodes 11. Subsequently, a 25μm thick PET film was laminated onto the intermediate layer 14 as the image receiving layer 13 to manufacture the image receiving sheet. With the electrodes of both the original plate A (and original plate B) and the image receiving sheet grounded, first, the plate layer 22 of original plate A and the image receiving layer 12 of the image receiving sheet 10, and the plate layer 32 of original plate B and the image receiving layer 13 of the image receiving sheet 10 were brought into close contact. Next, -1300V was applied to the electrodes 21 (and 31) of the original plate A and the electrodes 11 of the image receiving sheet 10 (and between the electrodes 31 of original plate B and the electrodes 11 of the image receiving sheet 10), with the electrodes 11 at ground potential. After the voltage was applied, with the electrodes of both the original plate A (and original plate B) and the image receiving sheet grounded, the image receiving sheet was separated from the original plates A and B. After developing the electrostatic patterns on the image-receiving layers of both sides of the image-receiving sheet with plateable charged particles, electroless copper plating was performed. A set of X and Y patterns for touch panel copper electrode circuits (both with wiring electrode section L / S=100 / 100 and mesh electrode section line width 5μm) was successfully formed on the image-receiving layers of both sides of the image-receiving sheet with the precision specified by the design. Furthermore, when the same image output experiment was conducted using an all-nickel master plate made by electroforming, the image in the recessed areas was developed accurately, and no traces of patterns or fogging were observed in areas other than the recessed areas, confirming that there was no static charge in the areas where the metal was in close contact with the image receiving sheet.

[0028] Let's consider the example of relief printing. If the same conditions and processes as in the previously mentioned intaglio example are applied, an electrostatic pattern will be created where the voids in the relief print are charged to -303V. In the next step, developing with a positively charged toner used in electrophotography will yield a visible image of the negative.

[0029] Let's consider an example using a gravure plate. As with the intaglio plate example mentioned earlier, the overall thickness of the plate and the depth of the void 22a (and void 32a) are both 20 μm. If the depth of the void 22b (and void 32b) in the shallowly engraved areas, which correspond to halftones in the image, is set to 10 μm, then if the plate layer material is conductive or semiconductor, the calculation is performed using the same method as in the intaglio plate example, with the voids set to 10 μm. The discharge initiation voltage is 374 V, the voltage applied to the voids is 516 V, and an electrostatic pattern of -142 V is created on the image receiving layer 12 (and image receiving layer 13). In this way, by creating differences in the depth of engraving on the same plate, it becomes possible to express halftones.

[0030] If the plate layer material is an insulator, the bottom surface of the recessed area will be charged, resulting in a different amount of charge on the image receiving layer 12 (and image receiving layer 13). Since the depth of the air gap 22b (and air gap 32b) is the same, the discharge initiation voltage is the same at 374V, but the voltage applied to the air gap 22b (and air gap 32b) is due to the 10μm at the bottom of the air gap in the plate layer. Assuming the relative permittivity of the plate layer is also the same at approximately 3.3, the voltage is 1300 × 10 / (10 + 15.2 + 3) = 461V. A voltage equivalent to -(461 - 374) = -87V is applied to the air gap 22b (and air gap 32b), causing the discharge to stop. The amount of positive and negative ions generated by the discharge is equal. The negative ions charge the image receiving layer 12 (and image receiving layer 13), and the positive ions charge the bottom surface of the recess in the plate layer. Therefore, the generated voltage is the ratio of the capacitances of each insulator (i.e., the ratio of the thickness in terms of air), resulting in the image receiving layer 12 (and image receiving layer 13) being charged to -73V, and the plate layer 22 below the air gap 22b (and the plate layer 32 below the air gap 32b) being charged to +14V. The charge on the plate layer 22 (and plate layer 32) can be removed before the next printing using an AC corona discharger or the like. Because the amount of toner deposited varies depending on the charge level of the image-receiving layer, the charge level will differ even with the same engraving depth due to differences in the material of the gravure plate layer, as described above. However, the gravure printing effect, which is the same as conventional printing, can still be obtained.

[0031] The configuration in which mask sheets are placed on both sides of the image receiving sheet and the electrostatic pattern formation process in the present invention are shown in Figure 2. The configuration of the image receiving sheet is the same as when the original plate is placed on both sides of the image receiving sheet. During ion irradiation, the mask sheet must allow ions to pass through only the ion-permeable openings, while blocking ions from all other surfaces. Therefore, the entire surface, excluding the ion-permeable openings, must be conductive. It is not necessarily required that the entire mask sheet be conductive. Thus, the mask sheet can consist of a molded body made solely of conductive material or a laminate of conductive and insulating materials, and must have predetermined ion-permeable openings. A mask sheet can be manufactured by creating ion-permeable openings in a sheet made of a conductive material such as metal foil or metal plate, or in a conductive layer sheet made by providing a conductive layer such as a metal film on a sheet of an electrically insulating material, using etching, laser processing, or a combination of these methods.

[0032] The ion irradiation method is not particularly limited. An ion irradiation method using corona discharge is preferred because it allows for processing in air, allows for easy switching of the polarity of the irradiated ions, and can be used for both pre-charging and ion irradiation.

[0033] The configuration of the image receiving sheet in which the original plate is placed on one side and the mask sheet on the opposite side, and the electrostatic pattern formation process in this invention, are shown in Figure 3. The configuration of the image receiving sheet, the original plate, and the mask sheet is the same as when the original plate or mask sheet is placed on both sides of the image receiving sheet.

[0034] Pre-charging can be performed on both sides of the image-receiving sheet before bringing the original plate and mask sheet into contact with it, yielding two benefits. First, it may result in uniform adhesion. However, the charge value must be lower than the discharge initiation voltage to prevent discharge from occurring between bringing the image-receiving sheet close to the original plate or mask sheet and ensuring contact. This value is sufficient to ensure the original plate and mask sheet adhere to the image-receiving sheet. Second, the electric field during the development stage becomes larger, potentially improving development efficiency. Since the adhesion effect of pre-charging is the same regardless of polarity, it is crucial to perform the pre-charging treatment with a charge of opposite polarity to the charge used to form the electrostatic pattern.

[0035] In applications requiring transparency, such as capacitive touch panels, the electrodes 11, image receiving layer 12, image receiving layer 13, and intermediate layer 14 must all be transparent. In applications where transparency is not required, it is not necessary for all of the electrodes 11, image receiving layer 12, image receiving layer 13, and intermediate layer 14 to be transparent.

[0036] The following mechanisms can be considered for electrostatic pattern formation. When both the master plate and the mask sheet are flat, the electrostatic pattern can be formed by placing the image receiving sheet between the master plates, or between the mask sheets, or between the master plates and mask sheets, pressing the master plates and / or mask sheets against the image receiving sheet, applying a voltage on the side where the master plates are in contact, irradiating with ions on the side where the mask sheets are in contact, and then separating the image receiving sheet from the master plates and / or mask sheets. In this case, the single-wafer image receiving sheets may be sequentially transported between the master plates, or between the mask sheets, or between the master plates and mask sheets, or the areas where the electrostatic pattern should be formed on the image receiving sheet, which has been drawn from a roll and unfolded into a strip, may be sequentially transported between the master plates, or between the mask sheets, or between the master plates and mask sheets, and the above operation may be performed. Even if the original plate and mask sheet are curved, similar operations can be performed if the curvature can be controlled so that the image-receiving layers on both sides of the image-receiving sheet are in close contact with each other, or between the original plate and the original plate, or between the mask sheets and the mask sheet. [Explanation of symbols]

[0037] 10 Image receiving sheet 11 Electrodes of the image receiving sheet 12 Image-receiving layer 13 Image-receiving layer 14. Middle Class A Original version A 21 Electrodes of original plate A 22. Plate layers of original plate A 22a void 22b void B Original version B 31 Electrodes of original plate B 32. Plate layer of original plate B 32a void 32b void M Mask Sheet M1 Ion-permeable opening L Mask Sheet L1 Ion-permeable opening 40 Ion irradiation means 50 Ion irradiation means P1 Electrostatic Pattern P2 Electrostatic Pattern P3 Electrostatic Pattern P4 Electrostatic Pattern P5 Electrostatic Pattern P6 Electrostatic Pattern P7 Electrostatic Pattern P8 Electrostatic Pattern P9 Electrostatic Pattern P10 Electrostatic Pattern P11 Electrostatic Pattern P12 Electrostatic Pattern P13 Electrostatic Pattern P14 Electrostatic Pattern P15 Electrostatic Pattern

Claims

1. Original plate A is composed of a second electrode having uniform conductivity across its entire surface and a plate layer made of an electrically insulating, conductive, or semiconductive material that is in close contact with and integrally formed on the second electrode and has an appropriate uniform thickness, and a relief, recessed, or gravure plate-like pattern is formed on the plate layer. Original plate B is composed of a third electrode having uniform conductivity across its entire surface and a plate layer made of an electrically insulating, conductive, or semiconductive material that is in close contact with and integrally formed on the third electrode and has an appropriate uniform thickness, and a relief, recessed, or gravure plate-like pattern is formed on the plate layer. The image receiving sheet is composed of a conductive layer which is the first electrode and image receiving layers laminated on both sides of the conductive layer. The method is characterized by arranging the original plate A and the original plate B with a gap between them so that their respective plate layers face each other, and placing the image receiving sheet between the original plate A and the original plate B. The plate layer of the original plate A and the image receiving layer of the image receiving sheet on the original plate A side, and the plate layer of the original plate B and the image receiving layer of the image receiving sheet on the original plate B side are brought into close contact, and an appropriate voltage sufficient to discharge the gaps in the relief, intaglio, or gravure plate-like patterns of the plate layers of the original plate A and the original plate B are applied between the second electrode of the original plate A and the first electrode of the image receiving sheet, and between the third electrode of the original plate B and the first electrode of the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer on one side of the image receiving sheet corresponding to the relief, intaglio, or gravure plate-like pattern of the plate layer of the original plate A, and an electrostatic pattern on the image receiving layer on the opposite side of the image receiving sheet corresponding to the relief, intaglio, or gravure plate-like pattern of the plate layer of the original plate B.

2. The mask sheet M consists of a molded body made solely of conductive material or a laminate of insulating material and conductive material, and is provided with predetermined ion-permeable openings. The mask sheet L consists of a molded body made solely of conductive material or a laminate of insulating material and conductive material, and is provided with predetermined ion-permeable openings. The image receiving sheet consists of a conductive layer which is the first electrode and an image receiving layer laminated on both sides of the conductive layer. The mask sheet M and the mask sheet L are placed facing each other with a gap between them, and the image receiving sheet is placed between the mask sheet M and the mask sheet L. A double-sided electrostatic printing method characterized by bringing the mask sheet M and the image receiving layer on the mask sheet M side of the image receiving sheet, and the mask sheet L and the image receiving layer on the mask sheet L side of the image receiving sheet into close contact, irradiating with ions through the mask sheet M and the mask sheet L, and then separating the mask sheet M and the mask sheet L from the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer on one side of the image receiving sheet corresponding to the ion-permeable opening of the mask sheet M, and an electrostatic pattern on the image receiving layer on the opposite side of the image receiving sheet corresponding to the ion-permeable opening of the mask sheet L.

3. The original plate A is composed of a second electrode having uniform conductivity across its entire surface, and a plate layer made of an electrically insulating, conductive, or semiconductive material that is in close contact with and integrally formed on the second electrode and has an appropriate uniform thickness, and a relief, recessed, or gravure plate-like pattern is formed on the plate layer. The mask sheet M is composed of a molded body made only of conductive material or a laminate of insulating material and conductive material, and has a predetermined ion-permeable opening. The image receiving sheet is composed of a conductive layer which is the first electrode and an image receiving layer laminated on both sides of the conductive layer. The original plate A and the mask sheet M are placed with a gap between them so that the plate layer of the original plate A and the mask sheet M face each other, and the image receiving sheet is placed between the original plate A and the mask sheet M. The plate layer of the original plate A and the image receiving layer of the image receiving sheet on the original plate A side, and the mask sheet M and the image receiving layer of the image receiving sheet on the mask sheet M side are brought into close contact. An appropriate voltage sufficient to discharge the voids in the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate A is applied between the second electrode of the original plate A and the first electrode of the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer of the image receiving sheet on the original plate A side corresponding to the relief, recessed, or gravure plate-like pattern of the plate layer of the original plate A. After ion irradiation through the mask sheet M, the mask sheet M is separated from the image receiving sheet, thereby forming an electrostatic pattern on the image receiving layer of the image receiving sheet on the mask sheet M side corresponding to the ion-permeable opening of the mask sheet M. A double-sided electrostatic printing method characterized by forming an electrostatic pattern on the image receiving layers of both sides of the image receiving sheet by generating discharge ions by applying a voltage between the electrode of the original plate and the electrode of the image receiving sheet on one side of the image receiving sheet, and by performing ion irradiation through the mask sheet on the opposite side of the image receiving sheet.

4. A double-sided electrostatic printing method according to any one of claims 1 to 3, characterized in that the image receiving sheet is pre-charged before being brought into contact with any combination of the original plate A and the original plate B according to claim 1, the mask sheet M and the mask sheet L according to claim 2, or the original plate A and the mask sheet M according to claim 3.

5. A double-sided electrostatic printing method according to any one of Claims 1 to 4, characterized in that the electrostatic pattern formed on the image receiving layers on both sides of the image receiving sheet is developed with charged particles using a dry development method or a wet development method in electrophotography.

6. A double-sided electrostatic printing method characterized in that the charged particles described in Claim 5 are plateable particles.

7. The double-sided electrostatic printing method according to claims 1 to 6, characterized in that the electrostatic pattern is for manufacturing an electrode circuit pattern.

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