Method for producing resin-molded substrate and method for producing reversible image display medium

Abstract

An initial resin substrate is formed by laminating resin layers, and one surface of the initial substrate is heated and pressed by a molding die to mold a projected and dented surface such that substantially no deformation occurs on the resin layer providing a surface opposed to the one surface of the initial substrate. A reversible image display medium is produced by a method comprising the steps of accommodating a dry developer into the concavities and fixing a second substrate to the first substrate using an adhesive. Alternatively a reversible image display medium may be produced by, e.g., a method comprising the steps of providing a first substrate having one surface including concavities, spreading the dry developer over the one surface, removing the excess developer while accommodating the developer into the concavities, and fixing a second substrate to the one surface, or alternatively forming a cell sheet having the cells and accommodating a dry developer therein by use of supersonic oscillation, magnetic force or vacuum suction force.

1 . A method for producing a resin-molded substrate having one surface which is projected and dented, the method comprising the steps of: forming an initial resin substrate by laminating a plurality of resin layers over each other; and heating and pressing one surface of the initial resin substrate by a molding die to provide a projected and dented surface, wherein the heating and pressing operation is carried out in a manner such that substantially no deformation occurs on the resin layer providing a surface opposed to the one surface of the initial resin substrate.  
   
   
       2 . The method according to  claim 1 , wherein the resin layer providing the one surface of the initial resin substrate has a lower softening point than the resin layer providing the surface opposed to the one surface of the initial resin substrate.  
   
   
       3 . The method according to  claim 1 , wherein the heating and pressing operation at the heating and pressing step is repeated.  
   
   
       4 . The method according to  claim 1 , wherein the molding die includes at least one transfer roller having an irregular peripheral surface for molding the one surface of the initial resin substrate into the projected and dented surface.  
   
   
       5 . The method according to  claim 3 , wherein a plurality of transfer rollers serving as the molding die are stepwise arranged, wherein the transfer rollers have irregular peripheral surfaces so stepwise varied as to eventually mold the one surface of the initial resin substrate into the projected and dented surface, and wherein at the heating and pressing step, the initial resin substrate is subjected to a plurality of heating and pressing operations using the plurality of transfer rollers stepwise arranged.  
   
   
       6 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: forming a resin-molded substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells by the method of  claim 1  for producing a resin-molded substrate; accommodating the dry developer into the concavities on the one surface of the resin-molded substrate formed at the resin-molded substrate forming step; and fixing another substrate to the one surface of the resin-molded substrate formed at the resin-molded substrate forming step with an adhesive composed of the same kind of resin material as that of the resin layer providing the one surface of the resin-molded substrate.  
   
   
       7 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: providing a first substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells; spreading the dry developer over the one surface of the first substrate; removing the excess developer while accommodating the spread dry developer into the concavities; and fixing a second substrate to the one surface of the first substrate in which the dry developer is accommodated, in the concavities to form the developer-accommodating cells containing the developer.  
   
   
       8 . The method according to  claim 7 , wherein at the developer spreading step, the dry developer is spread over the one surface of the first substrate by being supplied thereto while being subjected to supersonic oscillation.  
   
   
       9 . The method according to  claim 7 , wherein a dry developer containing dry magnetic developing particles is employed as the dry developer and is spread over the one surface of the first substrate using a magnet roller which carries the developer over its peripheral surface to transport the developer to a spot whereat the developer is to be spread, and supplies the developer to the one surface of the first substrate.  
   
   
       10 . The method according to  claim 7 , wherein at the developer-removing step, the excess developer is removed while the spread developer is accommodated into concavities by sliding a developer-removing member over the one surface of the first substrate on which the developer is spread.  
   
   
       11 . The method according to  claim 7 , wherein the first substrate has a plurality of developer-accommodating groove-like concavities serving as the concavities, which extend in parallel with each other, and at the developer-removing step, a developer-removing member is made to slide over the one surface of the substrate in a direction crossing the direction of groove-like concavities extending and then to slide over the one surface in the direction of the groove-like concavities extending.  
   
   
       12 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: forming a first substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells; forming a cell sheet by fixing a second substrate to the one surface of the first substrate, the cell sheet having the developer-accommodating cells between the first and second substrates; and accommodating the dry developer into the developer-accommodating cells of the cell sheet, wherein at the developer-accommodating step, the dry developer is accommodated into the developer-accommodating cells while giving supersonic oscillation to the cell sheet and/or the dry developer.  
   
   
       13 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: forming a first substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells; forming a cell sheet by fixing a second substrate to the one surface of the first substrate, the cell sheet having the developer-accommodating cells between the first and second substrates; and accommodating the dry developer into the developer-accommodating cells of the cell sheet, wherein at the developer-accommodating step, a dry developer containing dry magnetic developing particles is transported by a magnetic force to accommodate the developer in the developer-accommodating cells.  
   
   
       14 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: forming a first substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells; forming a cell sheet by fixing a second substrate to the one surface of the first substrate, the cell sheet having the developer accommodating cells between the first and second substrates; and accommodating the dry developer into the developer-accommodating cells of the cell sheet, wherein at the developer-accommodating step, the developer-accommodating cells are internally subjected to vacuum suction to force the developer into the cells by a vacuum suction force.  
   
   
       15 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: providing a first substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells; accommodating the dry developer into the concavities on the one surface of the first substrate; and fixing a second substrate to the one surface of the first substrate in which the developer is accommodated in the concavities to form developer-accommodating cells containing the developer; wherein at the second substrate fixing step, the first and second substrates are brought into contact with each other by reducing a gas pressure in the developer-accommodating cells.  
   
   
       16 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing-particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: providing a first substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells; accommodating the dry developer into the concavities on the one surface of the first substrate; and fixing a second substrate to the one surface of the first substrate in which the developer is accommodated in the concavities to form developer-accommodating cells containing the developer; wherein at the second substrate fixing step, the first and second substrates are fixed together using a hot melt adhesive which shows adhesiveness at a temperature lower than the softening temperature of the developer.  
   
   
       17 . A method for producing a reversible image display medium, which comprises two substrates opposed to each other with a predetermined gap therebetween; one or more developer-accommodating cells formed between the two substrates, each having a periphery surrounded by a partition wall; and a dry developer contained in each of the cell(s), wherein the dry developer contains at least two kinds of frictionally chargeable dry developing particles having different chargeable polarities and different optical reflection densities, the method comprising the steps of: providing a first substrate having one surface which is projected and dented and which includes concavities for forming the developer-accommodating cells; accommodating the dry developer into the concavities on the one surface of the first substrate; and fixing a second substrate to the one surface of the first substrate in which the developer is accommodated in the concavities to form developer-accommodating cells containing the developer; wherein at the second substrate fixing step, the first and second substrates are fixed together using a hot melt adhesive of reaction type.