Patent Publication Number: US-3879196-A

Title: Electrophotographic method for colored images

Description:
United States Patent 11 1 Nagashima et al.  
 1 Apr. 22, 1975 1 ELECTROPHOTOGRAPHIC METHOD FOR COLORED IMAGES [75] Inventors: Shinichiro Nagashima; Kaichi Tsuchiya: Yoshihiro Sakamoto; Hiroshi Yamakami. all of Tokyo: Seiji Tomari, Yokohama. all of Japan I [73] Assignee: Canon Kabushiki Kaisha, Tokyo.  
 Japan [22] Filed: Nov. 13, 1972 [21] Appl. No.: 305.672  
 [30] Foreign Application Priority Data 4/1966 Sullivan 117/363 3.244.549 4/1966 Farnham et a1 1 17/362 3.253.913 5/1966 Smith ct a1 96/l.2 3.329.590 7/1967 Rcnfrcw 96/12 3.466.185 9/1969 Taylor 117/362 3.491.111 1/1970 Chao-han Lin 117/362 3.491.116 1/1970 Chao-han Lin 117/362 3.717.463 2/1973 Bach ct a1 .1 96/12 Primary E.\&#39;uminer-Norman G. Torchin Assistant Evaminer-John L. Goodrow Arrurney. Agent. or Firm-Fitzpatrick. C ella. Harper &amp; Scinto 1 1 ABSTRACT An electrophotographic method comprises developing an electric latent image formed on a photosensitive member comprising a photoconductive material and 16 Claims, 7 Drawing Figures PATENIEDAFRZZISYS FIG. I  
 HEATING FIG. 2  
 FIG. 3  
 FIG. 5  
 FIG. 4  
 FIG. 6  
  x v k\\ &#34;Illllllllllllllllllll&#39;llm FIG. 7  
 ELECTROPHOTOGRAPIIIC METHOD FOR COLORED IMAGES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention and the invention described in our copending US. Pat. Application Ser. No. 293,160 filed Sept. 28, 1972 relate to a novel color forming electrophotographic method utilizing a toner for electrostatic image containing a color forming agent (A) and a photoconductive photosensitive member or an image receiving sheet containing a color forming agent (B), and further to a particular electrophotographic material used therefor.  
 2. Description of the Prior Art l-Ieretofore, there have been known various electrophotographic processes such as those disclosed in US. Pat. No. 2,297,691, Japanese Patent Publication No. 23910/1967 and Japanese Pat. Publication No. 24748/1968. In general, these electrophotographic processes comprise utilizing a photoconductive material, forming electric latent images on a photosensitive member, developing the latent images with a toner, if desired, transferring the developed image to an image receiving sheet such as paper and fixing the transferred image by heating or with solvent vapor.  
  It is widely known to use, as a developing toner, finely divided particles of 1 20 microns in diameter composed of a coloring pigment such as carbon black dispersed in a binder resin such as styrene resin. Such a toner is usually mixed with a carrier material su&#39;ch as glass beads, iron powder, fur and the like, or dispersed in an insulating liquid, and then attracted to or repulsed by the electrostatic latent image to visualize the negative or positive electric image.  
  The above-mentioned prior arts have the following three problems. The first problem is smudging during manufacturing and development since the toner is finely divided black powder. Such finely divided toner is so light that the toner is easily blown up to dirty remarkably hands, feet and clothes as well as room, and further to cause dust pollution outdoors.  
  The second problem is the main improving point of this invention. Hitherto, a copy image has almost been black color and it has been very difficult to form various color images such as red or blue by only one printer. The most difficult point was to prepare various color toner by adding various colored pigment or dyestuff to a thermoplastic resin which is a main raw material of a toner. When a pigment or dyestuff was added, charge of a toner was changeable, and a quality of an image fell down. Furthermore, even if such developing agent is prepared, since a developing agent must be exchanged in accordance with the desired color, an exchanging time of a developing agent, scattering of a toner of fine powder, soiling by a developing agent and the like became an issue. At present, black colored toner is only used and the various colored toners is not used in practical.  
  The third problem is concerned with fixation. In general, toner is fixed by heating, but when a switch is turned on and then immediately the reproduction operation starts, fixation of the resulting image is incomplete and when rubbed, the toner is easily removed. Thus, the fixed portion is preliminarily heated and brought to a sufficient temperature, and then the reproduction operation can start. Particularly, a necessary preliminary heating time is usually 5 -l0 minutes for dry reproduction machine, and when once the machine is switched on, the fixing device should be kept at a constant temperature until the business time is finished.  
  As an electrophotographic method using a color forming system, there may be mentioned that disclosed in Japanese Pat. Publication No. 15912/1966 which comprises covering a diazonium compound with wax and the like and combining with a paper coated with a coupler, that disclosed in Japanese Pat. Publication No. 989/1967 and Japanese Pat. Publication No. 3837/1970 which comprises using a volatile first chemical material as toner and a second chemical material (metal salt) as a reproduction sheet to form a colored image. However, when a diazonium compound is used as toner, there is disadvantageously a danger of explosion during pulverizing procedure and further and alkali treatment is necessary upon forming color, and therefore, it is not practical. Furthermore, in a system using a metal salt it is difficult to obtain clear and sharp color.  
 SUMMARY OF THE INVENTION This invention provides an electrophotographic method which can solve the above-mentioned drawbacks of prior art and in which a toner is colorless or of light color and a completely fixed image can be obtained without any waiting time in dry type developing.  
  An object of this invention is to provide a novel color forming electrophotographic method comprising forming a developed image on an image receiving sheet containing a color forming agent (B) infra by using a toner for electrostatic image containing a color forming agent (A) infra and applying a heating color forming treatment to form a visible image.  
  Another object of this invention is to provide an electrographic method that various colored images can be formed by changing a kind of a receiving image sheet even if the same toner is used.  
  A further object of this invention is to provide a colorless or light color toner for electrostatic image containing a color forming agent (A) infra which can form color by heating together with a color forming agent (B) infra.  
  A still further object of this invention is to provide an image receiving sheet containing a color forming agent (B) infra used for transferring an image formed by a toner for electrostatic image containing a color forming agent (A) infra.  
  Still another object of this invention is to provide an electrostatic transferring paper containing a color forming agent (B) infra.  
  This invention is an electrographic method which comprises developing an electric latent image formed on a photosensitive member comprising a photoconductive material and containing a color forming agent (B) infra in a surface for forming a visible image with a charged toner particle containing a color forming agent (A) infra, and heating to cause a thermal color forming reaction between the color forming agent (A) in the toner and the color forming agent (B) in the photosensitive member resulting in formation of a colored fixed image on the photosensitive member.  
  According to another aspect of this invention, there is provided an electrophotographic method as mentioned above in which the toner particle contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to a further aspect of this invention, there is provided an electrophotographic method as mentioned above in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  This invention is an electrophotographic method characterized in that comprises developing electric latent image formed on a photosensitive member using a photoconductive material with a charged toner particles containing a material selected from a color forming agent (A) group infra, transferring the resulting toner image to an image receiving sheet containing a material selected from a color forming agent (B) group infra, and heating to cause a thermal color forming reaction between the color forming agent (A) in the toner and the color forming agent (B) in the image receiving sheet resulting in formation of a colored fixed image on the image receiving sheet.  
  According to a still further aspect of this invention, there is provided an electrophotographic method as mentioned above in which the toner particle contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to still another object of this invention, there is provided an electrophotographic method as mentioned above in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to a still further aspect of this invention, there is provided an electrostatic recording method which comprises developing an electric latent image formed on an electrostatic recording paper containing a color forming agent (B) in the visible image forming surface with a charged toner particle containing a color forming agent (A), and heating to cause a thermal color forming reaction the color forming agent (A) in the toner and the color forming agent (B) in the electrostatic recording paper resulting in formation of a colored fixed image.  
  According to still another aspect of this invention, there is provided an electrostatic recording method as mentioned above in which the toner particle contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to a still further aspect of this invention, there is provided an electrostatic recording method as mentioned above in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary 4 agent having a melting point ranging from 40 to C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fattyacid amide, fatty acid anilide and solid plasticizer.  
  According to still another aspect of this invention, there is provided a recording method which comprises closely contacting a master sheet having a toner image containing a color forming agent (A) with a visible image forming surface containing a color forming agent (B) of an image receiving sheet and heating to cause a thermal color forming reaction between the color forming agent (A) and the color forming agent (B) resulting in a visible image.  
  According to a still further aspect of this invention, there is provided a recording method as mentioned above in which the toner image contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to still another aspect of this invention, there is provided a recording method as mentioned above in which the visible image forming surface of an image receiving sheet contains the color forming agent (13) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to a still further aspect of this invention, there is provided a toner for electrostatic image which comprises containing in a binder resin a material selected from the color forming agent (A) group infra.  
  According to still another aspect of this invention, there is provided a toner for electrostatic image as mentioned above in which the binder resin contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to a still further aspect of this invention, there is provided an electrophotographic photosensitive member which comprises a photoconductive material and a visible image forming surface of the photosensitive member containing a material selected from the color forming agent (B) group infra.  
  This invention is a photosensitive member for an electrography comprising a photoconductive material and containing a material selected from the color forming agent (B) group infra in a surface for forming a visible image.  
  Furthermore, this invention is a photosensitive member for an electrography in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group of fatty acid, fatty acid metal salt.  
  According to a still further aspect of this invention, there is provided an image receiving sheet which comprises a visible image forming surface containing a material selected from the color forming agent (B) group infra.  
  According to still another aspect of this invention, there is provided an image receiving sheet as mentioned above in which the visible image forming surface contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid. fatty acid metal salt. fatty acid ester. fatty acid amide, fatty acid anilide and solid plasticizer.  
  According to a still further aspect of this invention, there is provided an electrostatic recording paper which comprises a support layer and an electrostatic recording layer overlying the support layer and containing a material selected from the color forming agent (B) group infra.  
  According to still another aspect of this invention, there is provided an electrostatic recording paper as mentioned above in which the electrostatic recording layer contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.  
  A color forming agent (A) used in this invention is selected from the following group:  
 I. polymer of phenol and aldehyde,  
 2. polymer of phenol and acetylene,  
 3. rosin modified maleic acid resin, I  
 4. hydrolyzed product of copolymer of styrene and maleic anhydride,  
 5. hydrolyzed product of polymer of carboxy polyethylene,  
 6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,  
 7. hydrolyzed product of copolymer of ethylene and maleic anhydride,  
 8. Japanese acid clay,  
 9. bentonite,  
 l0. diatomaceous earth,  
 ll. bisphenol compounds containing carboxyl radi- BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows diagrammatically a conventional fixing procedure;  
  FIG. 2 shows diagrammatically a color forming and fixing procedure according to the present invention;  
 FIG. 3 shows a fixing apparatus;  
  FIG. 4 shows diagrammatically a cross sectional view of a master sheet according to the present invention;  
  FIG. 5 shows diagrammatically a cross sectional view of a printing member used in the present invention;  
  FIG. 6 shows diagrammatically a procedure for reproducing an image by using a master sheet of FIG. 4 and a printing member of FIG. 5; and  
  FIG. 7 shows diagrammatically a reproduction obtained in FIG. 6.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS The color forming agent (B) used in the present invention is basic material having a color forming group. Representative color forming agents (B) are shown below.  
 I. Diaryl phthalides:  
 3,3-bis(p-dimethylaminophenyl)-6-dimethylamino phthalide (Crystal Violet Lactone),  
 3,3-bis(p-dimethylaminophenyl)-phthalide (Malachite Green Lactone) and the like.  
 2. Leuco auramines:  
 N-halophenyl derivatives,  
 N-alkylhalophenyl derivatives,  
 N-(2,5-dichlorophenyl) leuco auramine, and the like.  
 3. Acryl auramines:  
 N-benzoyl auramine, N-acetyl auramine, and the like.  
 4. aft-unsaturated arylketones:  
 Dianisylidene acetone, Dibenzylidene acetone, Anisylidene acetone, and the like.  
 5. Basic monoazo dye:  
 p-dimethylaminoazobenzene-O-carboxylic acid (Methyl Red), l-aminoazobenzene (Oil Yellow AAB), 4-phenyla2ol-naphthylamine, and the like.  
 6. Rohdamine B lactone:  
 N (p-nitrophenyl)-rohdamine B lactone, 3,6&#39;-diamino rohdamine B lactone, 3,6&#39;-diethylamino rohdamine B lactone, 3,6-dimethylamino rohdamine B lactone, and the like.  
 7. Polyaryl carbinols:  
 Bis-(p-dimethylamino phenyl) methanol (michlers hydrol),  
 Crystal Violet Carbinol,  
 Malachite Green Carbinol,  
 and the like.  
 8. Benzoindolino spiropyrans:  
  8-methoxy benzoindolino spiropyran, 4,7,8&#39;-trimethoxy benzoindolino spiropyran, 6-chloro-8methoxy benzoindolino spiropyran and the like.  
 9. Phthalans:  
 I 1 -bis( p-aminophenyl )phthalan, 1,1-bis(p-benzylaminophenyl)phthalan,  
 l, 1 -bis( p-dibenzylaminophenyl )phthalan,  
  l, I -bis(p-N-methylamilinophenyl)phthalan, and the like.  
 10. Sprirophthalans:  
 6,6-diaminospiro (phthalan-l ,9-xanthen), 6,6&#39;-diethylaminospiro (phtha1an-l,9&#39;-xanthen), 6,6-dimethylaminospiro (phthalan- 1 ,9&#39;-xanthen) and the like.  
 Among the color forming agents (A) used in this invention, examples of (11) bisphenol compounds containing carboxyl radical in a molecule are:  
  7 8 I I no no G c 5 (1) v o&#34;! cn cn oi co 1 I H CH 0 .-4 on 2 i 2 (31-1 n and C001! p- 9 3 (Softening point 96- 109C, average degree of po1ymerization 40 45). CH Furthermore, examples of (A) phenolic material are A shown below: KZ/ P l5 4-tertiary-butyl phenol,  
  4-B-tertiary-amyl phenol,  
  2 4-phenyl phenol, 4,4-isopropylidene-bis-(2-chloro phenol), 4,4-isopropylidene-bis-(2-methyl phenol, l o 4,4&#39;isopropylidene-bis-(2-tertiary butyl phenol),  
 OOH L p 5 4,4-secondary-butylidene-bis-(2-methyl phenol),  
  2,2-dihydroxy diphenyl, 4,4&#39;-seco dar -but lidene di henol, Further, examples of (12) polymers of bisphenol catzchol p compounds containing carboxyl radical in a molecule 4 hydroxy aceto phenone, are: methyl-4-hydroxy benzoate,  
  4-hydroxy diphenoxide, 0 a-naphthol, 2 B-naphthol,  
  4-hydroxy diphenyl oxide, I CH I CHZCHZCOOH 2,2&#39;-methylene-bis-(4-chloro phenol),  
 2 2,2&#39;-methylene-bis-(4-methyl--tertiary-butyl phenol),  
  4,4&#39;-cyclohexylidene diphenol, n 4,4&#39;-cyclohexylidene-bis-(2-methyl phenol).  
  The reaction of the color forming agent (A) and the color forming agent (B), a kind of base-acid reactions, (softening point 92- 105C, average degree of poly- 40 according to the present invention, is illustrated by CH 4,4-isopropylidene-bis-(2,6-dibromo phenol), 4,4&#39;-isopropylidene-his-(2,6-dimethyl phenol), OH  
 merization 30 35) using a combination of malachite green lactone and and phenolic resin as an example.  
 (on N v I! (CH N 4 w N(CH ll i C phenolic&#39; :1 resin O Malachi t e Green lactone (MGL) The color forming agent (A) and the color forming agent (B) react mutually to form color.  
  These materials are described detail in the Japanese Pat. Publication No. 10788/1965, No. 9309/1965, No. 9310/1965, No. 3257/1967, No. 9071/1969, No. 10318/1969 and No. 11634/1969, and may be clearly used as a color forming main agent for the electrographic method of this invention.  
  Conventional electrophotographic methods are applicable to the production of electric latent image in the present invention. For example, there may be mentioned conventional electrophotographic methods such as a Carlson process comprising charging a whole surface of photoconductive layer composed of selenium, CdS, ZnO or an organic photoconductive material and then projecting a light image to form an electrostatic latent image and a method disclosed in Japanese patent publication No. 23910/1967 or 24748/1968 comprising uniformly charging a photosensitive member composed ofa photoconductive layer such as selenium and CdS and an insulating layer such as polyester overlying the photoconductive layer, applying corona charging simultaneously with imagewise exposure, and applying blanket exposure.  
  The electrostatic latent image thus obtained may be developed by a conventional developing method such as cascade developing methods, magnetic brush developing methods, fur brush developing methods and liquid developing methods, by using a tonerhaving charge opposite to that of the electrostatic latent image. In some particular cases, there may be used a toner having the same charge as that of the electrostatic latent image.  
  In the electrophotographic method according to the present invention, agent (A) alone in a form of finely deveded particle as toner to form an image, but the chargeability is poor and fog forms and moreover, color forming property is poor. Furthermore, there is formed sometimes are image composed of both negative and positive images. The thermal conductivity is so low that melting by heating is not sufficient and color forming efficiency is poor and the density of the resulting image is low. High fixing temperature is necessary and further, the color forming dye directly contacts atmosphere to cause deterioration of the color forming agent (A) due to moisture and oxygen.  
  The present inventors have successfully eliminated such disadvantages by dispersing the color forming agent (A) in a resin of relatively low melting point such as from 70 to 130C which has been used as a binder resin for an electrophotographic toner, such as vinsol resin, cumarone resin, polystyrene, polyvinyl acetate,  
 polyvinyl chloride, polyethylene, polyacrylic acid ester,  
 agent capable of low temperature fixation and improv ing the image density to attain the purpose.  
  The color forming auxiliary agent has a melting point ranging from 40 to 130C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer. These color forming auxiliary agent are mutually soluble with a binder resin, a color forming agent (A) and a color forming agent (B).  
  Representative color forming auxiliary agents are as shown below.  
 1. Fatty acids compounds,.for example,  
 Laurie acid (44C) Tridccylic acid (455C) Myristic acid (58C) Pentadccylie acid (53 54C) Palmitic acid (63 64C) Heptadecylic acid (60 61C) Stearic acid (71.5 72C) Nonadecanoie acid (687C) Arachic acid (77C) Bchenic acid (81 82C) Lignoceric acid (815C) Cerotic acid (879C) Heptacosanoic acid (82C) Montanic acid (893C) Melissic acid (93.5 94C) Laeeeric acid 96C) and the like.  
  The numbers in the parenthese are melting points. The preferable color forming auxiliary agents are fatty acids containing 12 and more than of carbon atom and having melting points ranging from 40 to C.  
 2. Metallic salts of fatty acids having melting points ranging from 40 to 130C are shown by the following general formula:  
 (R C O O)&#34; M where n 1- 3;M is Be, Mg, Ba, Zn, Cd, Hg, Al, Tl, Pb and the like; R is an alkyl radical.  
 Representative examples are as follows:  
 Lead caproate (m.p. 73 74C) Lead enanthate (m.p. 78C) Lead caprylate (m.p. 83 84C) Lead pclargonate (m.p. 94 95C) Lead caprate (m.p. 100C) Lcad laurate (mp. 106C) Lead myristatc (m.p. 1()8.6C) Lead palmitatc (m.p. 112C) Lead stearatc (mp1 1 16 C) Lead tridecylate (m.p. 128C) Aluminium stearate (m.p. 105C) Beryllium stcarate (m.p. 45C) 3. Fatty acid derivatives having melting points ranging from 40 to 130C, which are represented by the following formula;  
 where R is alkyl;R&#39; is alkyl or aryl.  
 Representative examples are as follows:  
 (i) Methyl esters:  
 Methyl arachinate (m.p. 46 47C) Methyl behenate (m.p. 54C) Methyl lignocerate (m.p. 56.7 57C) Methyl cerotinatc (m.p. 63C) Methyl heptacosanate (m.p. 64C) Methyl montanatc (m.p. 685C) Methyl mclissinate (m.p. 715C) Ethyl esters:  
 Ethyl arachinate (m.p. 42C) Ethyl hchenate (m.p. 50C) Ethyl lignoceratc (m.p. 56.7 57C) (iii) where R is alkyl; R and R&#34; is H, alkyl, or aryl. Representative examples useful for this invention are as fol- -Continued Ethyl cerotinate (m.p. 60C Ethyl montanate (m.p. 64 65C) Ethyl mclissinate (m.p. 705C) Ethyl lacccrate (m.p. 76C) Phenyl esters: Phenyl arachinatc (m.p. 585C) Phenyl palmitinate (m.p. 45C) Glycol esters:  
  Glycol myristatc (m.p. 64C Glycol palmitinatc (m.p. 515C) Glycol stearate (m.p. 58 75C) Glycerol esters:  
 Glycerol laurate (m.p. 63C) Glycerol myristate (m.p. 56 705C) Glycerol palmitinate (m.p. 34 77C) Glycerol stearatc (m.p. 54 71C) lows:  
 (i) Amidcs:  
 Acetic amides (mp. 82 83C) Propionic amide (m.p. 818C) Butyric amide (m.p. ll5 116C) Valerie amide (m.p. 106C) Caproic amide (m.p. 101C) Enantic amide (m.p. 93 94C) Caprinic amide (m.p. 105.9C) Peralgonoic amide (m.p. 989C) Undccylic amide (m.p. 84.5 855C) Laurie amide (m.p. 102.4C) Tridecylic amide (m.p. 100C) Myristic amide (m.p. l05.lC) Pentadecylic amide (m.p. 102C) Palmitic amide (m.p. 107C) Hcptadccylic amide (m.p. 108 109C) Stearie amide (m.p. 109.7C) Arachic amide (m.p. 108C) Behenic amide (m.p. 111 112C) Cerotic amide (m.p. 109C) Montanic amide (m.p. 112C) (ii) Anilides:  
 Valeric anilide (m.p. 68C) Caproic anilidc (m.p. 92C) Caprylic anilide (m.p. 55C) Pcralgonoic anilide (m.p. 575C) Capric anilide (m.p. 625C) Undecylic anilidc (m.p. 71C) Laurie anilidc (m.p. 77.2C) Myristic anilide (m.p. 84C) Palmitic anilidc (m.p. 902C) Stcarie anilide (m.p. 94C) Behenic anilide (m.p. 101 102C) (iii) N-Methyl amides:  
 Capric methyl amide (m.p. 57.8C) Laurie methyl amide (m.p. 624C) Myristic methyl amide (m.p. 78.4C) Palmitic methyl amide (m.p. 855C) Stearic methyl amide (m.p. 92.lC)  
 (iv) N-Dodeeylic amides:  
 Laurie dodceyl amide (m.p. 77 775C) Myristic dodceyl amide (m.p. 84 C) Palmitic dodceyl amide (m.p. 82.5 85C) Stearic dodceyl amide (m.p. 85 855C) high color forming efficiency, good low temperature 65 fixation, and colored image copy having sharp and sufficient density. Such improvement is considered due to that the color forming auxiliary agent melts at relatively low temperature and the color forming agent (A) and the binder resin and further the color forming agent (B) in the photosensitive member or transferring paper are mutually soluble with the color forming auxiliary agent to cause coloring and fixing at a low temperature and enhance the color forming density.  
  It has been further found from experiments shown later that the color forming auxiliary agent gives a good result when the color forming auxiliary agent is added together with the color forming agent (B) to a visible image forming surface of the electrophotographic photosensitive member or image receiving sheet.  
  The amount of the color forming auxiliary agent is usually more than 5 parts preferred with 5 20 parts, particularly preferred with 8 12 parts, per parts of the color forming agent (A).  
  Then when the color forming auxiliary agent is added to the visible image forming surface of the receiving image sheet with the color forming agent (B), the amount of the color forming auxiliary agent is 50 250 parts, preferred with 80 parts per 100 parts of the color forming agent (B) though it varies a little in accordance with a material of the color forming agent.  
  A suitable binder is used to adhere a color forming agent (B) and a color forming auxiliary agent on the surface of a receiving image sheet of a photosensitive member or electrostatic recording paper used for this invention.  
  Representative binders include aeetylized starch, styrene-butadiene latex, polyvinyl pyrrolidone, acryl latex, polyvinyl alcohol, soy albumin, casein, oxyethylized starch or these mixture. Further, antioxidant, emulsifier, antiforming agent, ultra violet ray absorber, and the like may be used with a binder, but phenol series antioxidants are not preferable because of being danger of color forming reaction with a color forming main agent. The ultra violet ray absorber, for example, Tinubin Ps, P320, P326, P327, P328 (trade mark, supplied by Geigy Co.) and the like, can prevent coloring of paper by adding to a receiving image sheet. A paper sheet or web is usually used as a receiving image surface in electrostatic image method. The paper may be comprised of organic and or inorganic fibres such as cellulose, modified cellulose, polymerized cellulose, glass or asbesto-fibre.  
  A color forming agent (B) is added to paper at a free step of preparation of paper. The amount of a color forming agent (B) of 0.5 1.5 g., preferably 0.7 1.0 g. per lm of the coating surface is useful for color forming reaction with a toner containing a color forming agent (A).  
  When a color forming agent (B) has been combined into paper in heating step before forming of sheet or is combined into paper after forming of web, a comparatively large amount of a color forming agent (B) is necessary for maintaining sufficiently large amount of a color forming agent (B) on a surface of a paper sheet, and about 1.0 2.0 g. of a color forming agent (B) per 1 m of the image surface gives a good result.  
  The relation between an amount of coating per 1 m and an image density is different in accordance with a toner. 1  
  The image density was measured by effecting a color forming reaction at 180C between the toner of phenol formaldehyde resin (Trade Mark RB-lOO manufac- 13 tured by Mitsui Toatsu Co.) and the receiving image sheet of Example 1.  
  The relation between a coated amount and an image density is illustrated at Table l.  
  This result indicates that waiting time of a copier can be shortened to a great extent.  
  The following experimental examples are given for illustrating the improvement accomplished by the present invention. In the experimental examples, ingredi- Table l ents are mixed at the weight ratio as listed in the followcoatcd amount of ing tables and melted and cooled, and then pulverized Crystal viola Lacmne lmage Density by using a jet mill to form a toner of less than 20 mi- 0 a 2 crons in size. Ten parts by weight of the resulting toner 8&#39;2 was mixed with 90 parts by weight of iron powder of 50 6 n microns in size, and image formation was effected by -g using NP 1100 Electrophotographic apparatus (manu- 1 factured by Canon Co.) and the resulting image was evaluated. A receivin ima e sheet used was t e-s me Now referring to FIG. 1 and FIG. 2 by the example as that of Exampl&#39;e g h a of dry developmg there explamed the The evaluation of each experimental example is conence between coloring and fixation of the present inducted as shown below. vention and fixation of conventional electrophotographic method. According to conventional method, a l. Pulverizing property: toner image 2 formed on a support 1 such as paper is good already colored before heatfixation and can be fixed to fairly good support 1 by heat-fixing at relatively high temperature. somewhat bad On the contrary, according to the color forming fixing bad method of the present invention, a color forming agent 2. Maximum color forming density, layer 4 is formed on a support 1 such as paper and a Fog density: toner image 3 containing a color forming agent (A) Reflective density is measured by MACBETH formed on the color forming agent 4 is colorless or of quantalog densitometer RD-l00 with a red fillight color. When these are heated at a relatively low ter. temperature and melted to cause a color forming reac- 3. Chargeability: tion with a color forming agent (B) layer 4 resulting in Mixing an iron powder carrier with a sample the colored portion 3a. As is clear from above, a contoner and measuring polarity of charge, negaventional toner image is often removed by rubbing tive or positive. while a colored image according to the present inven- 4. Fixing temperature: tion is not removed at all by rubbing. Measured by a method as mentioned above:  
 Table 2 Maximum Poly- Phenol* Stearic Pulvcriz- Color Fog Fixing harge- Experiment styrene Com- Acid ing ability Forming Density Temperpounds No. property Density ature l 70 parts 20 parts 0 parts 8 0.5 0.0l 230C 2 5 1.2 0.01 170 3 l0 0 L2 0.015 I60 4 20 O 0.9 0.04 150 5 30 A 0.7 0.04 l50 6 A 0.7 0.04 140 7 5 l5 8 0.7 0.01 l 8 l0 0.7 0.0] 150 9 20 0.9 0.03 I60 10 30 1.2 0.03 200 ll 40 I 1.2 0.04 220 12 60 1.2 0.04 220 The phenol compound is 4,4-isopropylidcncdiphenyl.  
  Conventional dry toner (thermoplastic resin carbon system) is compared with the toner of the present invention (Example 1) with respect to fixing temperature by using a fixing apparatus as illustrated in FIG. 3.  
  As shown in FIG. 3, four 250W infrared heaters 5 are arranged and a conveyor 8 of 200 mm long moves at l23 mm/sec. and a transferring sheet moves thereon to form color and fix. Reference numbers 6, 7, 8, 9 and 10 denote a heating insulating material, a gear, a wire net conveyor, a thermometer and a variable thermostat, respectively.  
  By using this fixing apparatus each fixing temperature was measured.  
 Fixing temperature (in thel glgpcaratus) Toner of the present invention Conventional toner The results of the experiments using myristic acid, aluminium stearate, lead caprylate, glycerol stearate, glycol stearate, methyl behenate, lauric acid amide, lauric acid anilide, lauric acid dodecyl amide and the like in place of stearic acid in the above mentioned experiment were almost the same each other.  
  The above results indicate that increase in addition amount of a charge controlling resin (styrene polymer and the like) to a color forming auxiliary agent results in lowering of color forming efficiency and low temperature fixing efficiency so that any satisfactory image can not be obtained. As the added amount of a color forming auxiliary agent increases to the charge controlling resin, the controlling effect is lowered and blur is formed at detailed portion of image and image quality is lowered though low temperature fixation proceeds further.  
  As the added amount of a color forming agent (A) increase to a charge controlling resin, the controlling effect is lowered in a manner similar to a color forming auxiliary agent and the color forming efficiency is not increase so much.  
  The experiment on the action and effect of the color forming auxiliary agent on a surface of a receiving image sheet in this invention is given.  
  The effects such as fixing temperature and color forming density on each ratio of Crystal Violet Lactone as a color forming agent (A) and stearic acid as a fatty acid were measured. The results were illustrated in Table 3.  
  This results is almost similar to other color forming agents (B) and other color forming auxiliary agents.  
  When a fatty acid such as stearic acid is a little, the color forming and fixing temperature is high. On the contrary, when the ratio of stearic acid increases, stearic acid remarkably penetrates into an image receiving sheet upon melting of stearic acid and the paper becomes transparent. Serious drawback caused by increased amount of stearic acid is that the color forming density is low. The optimum point where low temperature fixation is possible and no transparency occurs and further the color forming density is high is at a ratio of a color forming auxiliary agent to a color forming agent (B) being 25 130 parts, preferably, 40 60 parts per 50 parts.  
 nitrile 6 z 4), styrene-acrylester (methyl, ethyl, butyl ester etc.) copolymer (styrene acrylester 4-9 6-1 styrene-acrylonitrile-indene copolymer (styrene acrylonitrile indene 5 3 2) and the like are preferable, and in particular, a negative toner is obtained easily by using polystyrene and a positive toner is obtained easily by using polyethylene phthalate, epoxy resin or polyamide resin. Then charge controllability may be controlled by using the dyestuffs mentined in Japanese Pat. Publication No. 26478/1970. Furthermore, it is preferable to use polymers of color forming agent (A) together. Of course, polymers of color forming agent (A) may be used alone.  
  Defects in using the above mentioned polymers are a comparatively low color forming density, and colorizing stronger than phenol compounds having low molecular weight and the like, and the advantages are improvement in light resistance (when the above mentioned polymers are not used, color of a toner fades after exposing for about 1 week to a direct ray of the sun, but when used, an image remains even after exposing for 1 month under the same condition as the above case), easy preparation of toner for the wet system, good stability of particles, and easy fixation at room temperature.  
  As preparation methods for liquid developer, there are a method diffusing fine particles obtained by a dry Table 3 Crystal Violet Lactone Stcaric Acid I074 Polyvinyl Fixing Maximum (Color forming (Color forming alcohol Temperature lmagc Note agent (8)) auxiliary solution Density agent) 20 parts 0 parts 150 parts 230C 0.5 low D l0 170 1.2 good ,1 20 H I 50 I,  
 II ll II I! 120 L3 Semitransparent receiving image sheet I, n &#39;00 I. I,  
 &#34; 60 90 transparent receiving image sheet I! 70 H 70 H I,  
 &#39; Dm, is maximum image density.  
  The data of Table 3 were values measured by using the receiving image sheet prepared by coating 2 3 microns of thickness of the aqueous solution of a color forming agent (B), a color forming auxiliary agent, polyvinyl alcohol and sodium salt of rosin and the same toner as that of Example 1. Fixing temperature and &#39;maximum image density were measured by the same method as the above mentioned experiment.  
  In this invention, the toner used in case of developing by liquid developing method is comprised of a color forming agent (A), a color forming auxiliary agent, charge controlling resin and the like, and the preferable agents and rosin are as follows.  
  As color forming agents (A), phenol compounds having low molecular weight such as 4-4&#39;-isopropylidene diphenyl, 4-4-bis(hydroxyphenyl) butyric acid, 4-4&#39;-bis(4-hydroxylphenyl pentanic acid and the like are preferable. As charge controlling resins, polystyrene. styrene-acrylonitrile copolymer (styrene acrylosystem, a method of dispersing a resin solution in a solvent into a non-solvent i.e. insulating carrier.  
  in the former method, the raw materials of a toner are melted, mixed and ground to obtain particles of 0.5 1.0 micron of particle size. The particles thus obtained are dispersed into an insulating carrier (e.g. lsopar H: manufactured by Esso Standard Oil Co.) with an anionic dispersing agent. In the latter method, the raw materials are roughly dispersed into a non-solvent after dissolving in a solvent, and then are dispersed finely by a colloid mill or a ball mill to form a developer.  
 image obtained by transferring to a transferring member may be also used as a printing master sheet. The master sheet is contacted with an image receiving sheet containing a color forming agent (B) and heated to cause a thermal color forming reaction of a color forming agent (A) with a color forming agent (B) resulting in a visible image. This process can be repeatedly conducted by using a new image receiving sheet to produce many sheets of reproduction.  
  Referring to the drawing, the above process is explained further in detail. A master sheet is prepared by forming an image containing a color forming agent (A) on a surface of a support such as paper, film, electrophotographic photosensitive plate and the like. Referring to FIG. 4, there is illustrated an embodiment of a master sheet. A toner image 12 containing a color forming agent (A) is formed on a paper, film or electrophotographic photosensitive plate 11.  
  Referring to FIG. 5, there is shown a printing member in which a color forming agent (B) layer 13 is provided on an appropriate support 14 such as paper, cloth, film and the like.  
 Referring to FIG. 6, the master sheet in FIG. 4 and the printing member in FIG. are used for reproduction. A master sheet 11, 12 is placed on a plate 17 and a printing member 13, I4 is placed on the master sheet by facing the color forming agent (B) layer to the toner image of the master sheet. A box 15 composed of glass or a thermally conductive material provided with a heater 16 such as infrared ray heater, nichrome wire heater and the like is pressed to the printing member. Thus, a thermal reaction is caused to produce color forming images 18 as shown in FIG. 7. In other words, a part of image containing a color forming agent (A) is absorbed into a layer containing a color forming agent (B) of the printing member, transferred thereto and a color forming reaction occurs to form a colored image by pressing and heating. Further, many reproduction can be obtained by repeating the abovementioned procedure. Images containing a color forming agent (A) may be produced by various methods. For example, an image is written by hand using an ink containing a color forming agent (A). An image can be formed by an electrophotographic process. A photoconductive photosensitive member, e.g. photoconductive zinc oxide paper, is charged and exposed by a known method, and then subjected to dry development by a magnetic brush method or cascade developing method using a toner containing a color forming agent (A) or wet development by a liquid developer composed of toner containing a color forming agent (A) dispersed in an isoparaffin high insulating liquid. The resulting toner images produced on the zinc oxide paper is used as a master sheet. The light image as used in the above procedure for exposure is a mirror image with respect to the original image.  
  A photoconductive layer of a photoconductive selenium photosensitive drum or a photoconductive zinc oxide photosensitive drum is charged and exposed by a known method and developed with dry developer by a known magnetic brush or cascade developing method. The resulting toner image can be used as a master sheet, or the toner image transferred to an other sheet may be used as a master sheet.  
  A photoconductive selenium photosensitive plate or photoconductive zinc oxide layer is charged, exposed by a known method, and developed with a toner containing a color forming agent (A) dispersed in an isoparaffine high insulating carrier, and the image thus developed or the developed image further transferred to an other sheet can be used as a master sheet.  
  A selective discharging is applied to a photoconductive layer, such as selenium layer, having an insulating film, and a dry or liquid developer containing a color forming agent (A) is used for development. The resulting toner image can be used as a master sheet.  
  According to the above printing methods, it is possible to produce many sheets of multicolor printing. In a recording method using a thermal color forming reaction of a color forming agent (A) with a color forming agent (B), a plurality of master sheets corresponding to spectrally divided color which has a toner image containing a color forming agent (A) capable of producing a color corresponding to each spectral color. These master sheets are sequentially pressed to a printing member having a color forming agent (B) containing surface and heated by heating at least one of the master sheet and the printing member.  
  An example of color heat sensitive printing method is as shown below. Master sheets are prepared by an electrophotographic means. In usual, three master sheets i.e. red, blue and green master sheets, corresponding to three divided visible spectra, are prepared.  
  First photoconductive photosensitive layer sheet after charged is exposed to a light image through a red filter and developed with a color forming agent (A) capable of giving cyan color. Second photoconductive photosensitive layer sheet after charging is exposed to a light image through a green filter and developed with a color forming agent (A) capable of giving magenta color. Third photoconductive photosensitive layer sheet after charging is exposed to a light image through a blue filter and developed with a color forming agent (A) capable of giving yellow color. The resulting three sheets are used as master sheets. Then, these three master sheets are sequentially pressed to a printing paper containing a color forming agent (B) and heated by using an apparatus as shown in FIG. 6. According to the above mentioned method, fusing color forming is effected by heating so that a mixed color can be obtained since the later formed color does not suppress the former formed color.  
  According to the above mentioned method, a complicated and expensive printing machine is not necessary, and many sheets of reproduction can be easily and quickly obtained.  
  The resulting printed matter is of high density and good quality.  
  A color forming agent (A) and a color forming agent (B) are usually separated from each other so that the printed matter is stable against light and heat as compared with conventional heat sensitive reproduction.  
  The following examples are given for illustrating the present invention, but should not be construed as limiting the present invention.  
  The parts in the following examples are by weight unless otherwise indicated.  
 EXAMPLE 1 Twenty parts of 4,4&#39;-isopropylidene diphenyl, 15 parts of myristic acid and parts of polystyrene were mixed, melted, cooled and ground by a jet mill grinder into a particle size of 5 20 microns to produce a toner.  
  One part of the obtained fine powdered toner was mixed with 3 30 parts, preferably 5 10 parts, of iron powder (i.e. a carrier). (The particle size of a carrier was 20 microns, preferably 25 50 microns.)  
  A carrier was charged positively and a toner was charged negatively in the developing agent obtained from the toner and the carrier.  
  Then a toner image was formed by developing the electro latent image on a insulating layer obtained by the electrographic method disclosed in Japanese Patent Publication No. 23910/1967 by the magnet brush method with the above mentioned developing agent.  
  Twenty parts of Crystal Violet Lactone, 180 parts of 10% aqueous solution of polyvinyl alcohol and 0.5 parts of emulsifier (trade name: Dresinate X) were mixed and ground by a ball mill for 24 hours, to which 50 parts of water was added to obtain a coating solution. A paper was coated with the coated solution in the amount of 7 g./m. to obtain a transferring paper. The toner image was transferred to the transferring paper and heated at l80C to form blue color in the portion where the powder image was transferred. The resultant copy was clear. The resultant image was not vanished even when rubbed strongly by an eraser.  
  The transferring papers were produced by using (1) Rohdamine Lactone, (2) Malachite Green Lactone and (3) 8&#39;-methoxyindolinospiropyran in place of Crystal Violet Lactone. The toner image developed with the same toner was transferred to three kinds of transferring paper. Three transferred images were each heated to obtain a red copy on (1), a green copy on (2) and a black copy on (3).  
 EXAMPLE 2 Twenty parts of 2,2&#39;-dihydroxydiphenyl, 15 parts of lead capronate and 70 parts of polystyrene were mixed, melted, cooled and ground by a jet mill into a particle size of 20 microns to obtain a toner.  
  One part of the obtained fine powdered toner was mixed with 3 30 parts, preferably 5 10 parts of iron powder (i.e. a carrier).  
 Then a toner image was formed by developing the electrostatic latent image on an insulating layer obtained by the electrographic method mentioned in Japanese Patent Publication No. 23910/1967 by the magnet brushing method by using the above mentioned developing agent.  
  Then, 20 parts of Malachite Green Lactone, and 40 parts of stearic acid were mixed and melted by heating, were added to 150 parts of 10% aqueous solution of polyvinyl alcohol at 80C, were dispersed by adding emulsifier (trade name: Dresinate X), to which 40 parts of water was added and cooled to prepare the coating solution. The coating solution was coated on a paper in the amount of about 7 g./m. and was dried to obtain a transferring paper.  
  The above mentioned toner image was transferred to the transferring paper and heated at about 180C, and the portion where the toner image was transferred formed green color to obtain a clear copy. The resultant image was not vanished even when rubbed strongly with an eraser.  
 EXAMPLE 3 Twenty parts of phenolic resin, parts of palmitic acid phenyl and 70 parts of polystyrene were mixed, melted, cooled and ground by a jet mill grinder into a particle size of 5 microns to obtain a toner.  
 One part of the obtained fine powdered toner was 20 mixed with 3 30 parts, preferably 5 10 parts, of iron powder (i.e. a carrier).  
  Then a powder image was formed by developing the electrostatic latent image on an insulting layer obtained by the electrographic method disclosed in Japanese Patent Publication No. 23910/1967 by the magnetic brush method by using the above mentioned developing agent.  
  Twenty parts of Rohdamine leuco Lactone and 40 parts of ethylene glycol dibenzoate were heated to melt, added to 150 parts of 10% aqueous solution of polyvinyl alcohol at 80C, dispersed by adding emulsifier (trade name: Dresinate X), to which 40 parts of water was added, and cooled to obtain the coating solution. The coating solution was coated on a paper in the amount of about 7 g./m. and was dried to obtain a transferring paper.  
  The above mentioned toner image was transferred to the transferring paper and was heated to about 180C to form green color in the portion where the powder image was transferred. The resultant copy was clear. The resultant image was not vanished when rubbed strongly with an eraser.  
 EXAMPLE 4 Twenty parts of p-cresol, 15 parts of lauric acid amide and parts of polyester resin were mixed, melted, cooled and ground by a jet mill grinder into a particle size of 5 20 microns to obtain a toner.  
  Then 1.0 part of acrylic resin, 4.0 parts of zinc oxide, 2 parts of 8-methoxybenzoindolinospiropyran and a mixed solvent of xylene and toluene (50 50) were mixed in a ball mill for 24 hours, to which the above mentioned solvent was added to obtain the coating solution having viscosity of 1 l0 c.p. The photosensitive paper comprised of ZnO-acrylic resin binder was coated with the coating solution in the amount of 4 5 g./m. The photoconductive layer was uniformly charged with a corona discharger, and then, exposed to a light pattern to form an electrostatic latent image, which was developed by the above mentioned toner. The obtained toner image was heated at a temperature of about C to form black color in the portion of the powder image. The resultant copy was clear.  
 EXAMPLE 5 Twenty parts of 4-ter-butyl phenol, 15 parts of stearic acid anilide and 70 parts of polystyrene were mixed, melted, cooled and then ground by a jet mill grinder into a particle size of 5 20 microns to obtain a toner.  
  One part of the fine powdered toner was mixed with 3 30 parts, preferably 5 10 parts, of iron powder (i.e. a carrier).  
  The electrostatic latent image obtained on an insulating layer by the electrographic method disclosed in Japanese Patent Publication No. 23910/1967 was developed with the above mentioned developing agent obtained above by means of magnetic brush technique to form a toner image.  
  Forty parts of styrene-maleic acid copolymer, 200 parts of methanol and 20 parts of 3,6&#39; diaminospiro(phthalan-l ,9-xanthene) were mixed and ground in a ball mill, to which 300 parts of methyl ethyl ketone was added to obtain fine particles coated with 3&#39;,6&#39;-diaminospiro(phthalan-l,9&#39;-xanthene) resin. The  
 fine particles was classified and mixed with 150 parts of a 10% aqueous solution of polyvinyl pyrrolidone and 40 parts of water to obtain a coating solution. A paper was coated with the coating solution to obtain a transferring paper.  
  The above mentioned powder image was transferred on the transferring paper and heated at about 200C to form black color in the portion where the powder image was transferred. The resultant copy was clear.  
 EXAMPLE 6 Twenty parts of 4-hydroxyacetophenol, 15 parts of lauric acid and 70 parts of polystyrene were mixed, melted, cooled and ground by a jet mill grinder into a particle size of 20 microns to obtain a toner.  
  One part of the toner and 3 30 parts, preferably 5 parts, of iron powder (i.e. a carrier) were mixed.  
  The electrostatic latent image produced on an insulating layer by the electrographic method disclosed in Japanese Patent Publication No. 239l0/l967 was developed with the above mentioned developing agent produced above by means of magnet brush technique to form a toner image.  
  Twenty parts of Crystal Violet Lactone and 40 parts of lead stearate were heated to melt, and added to 150 parts of 10% aqueous solution of polyvinyl alcohol heated at 80C and 0.5 parts of emulsifier (trade name: Dresinate X), to which 40 parts of water was added and cooled to obtain a coating solution. A paper was coated with the coating solution in the amount of about 7 g./m. and dried to obtain a transferring paper.  
  The above mentioned powder image was transferred to the transferring paper and heated at about 180C to form blue color in the portion where the powder image was transferred. The resultant copy was clear. The resultant image was not vanished even when rubbed strongly with an eraser.  
 EXAMPLE 7 Twenty parts of hydrolysis product is carboxypolyethylene polymer, parts of palmitic acid methylamide and 70 parts of polystyrene were mixed, melted, cooled and then ground by a jet mill grinder into a particle size of 5 microns to obtain a toner.  
  One part of the toner and 3 parts; preferably 5 10 parts, of iron powder were mixed.  
  The electrostatic latent image obtained on an insulating layer by the electrographic method disclosed in Japanese Patent Publication No. 23910/1967 was developed with the above mentioned developing agent obtained above by means of magnet brush method to form a toner image.  
  Twenty parts of l,l-bis(p-aminophenyl)phthalan and 40 parts of stearic acid dodecylamide were heated to melt, and added to 150 parts of 10% aqueous solution of polyvinyl alcohol heated at 80C, to which 0.5 parts of emulsifier (trade name: Presinate X) was added and thereafter 40 parts of water was added to the coating solution. After the coating solution was cooled, a paper was coated with the coating solution in the amount of about 7 g./m. and dried to obtain a transferring paper.  
  The above mentioned toner image was transferred to the transferring paper and heated at about 180C to form violet color in the portion where the toner image was transferred. The resultant copy ws clear. The resultant image was not vanished even when rubbed strongly with an eraser.  
 EXAMPLE 8 The following materials (1 (6) were used in place of hydrolysis product of carboxypolyethylene polymer, and other procedure were the same as that of Example 7, and the result was the same as that of Example 7.  
 l. Phenol acetylene polymer 2. Phenol aldehyde polymer 3. Hydrolysis product of vinyl methyl ether maleic acid anhydride copolymer 4. Hydrolysis product of ethylene maleic acid anhydride copolymer 5. l-lydroylsis product of styrene maleic anhydride copolymer 6. Rosin-modified maleic acid polymer EXAMPLE 9 Twenty parts of a-naphthol, 15 parts of lauric acid methylamide and parts of polystyrene were mixed, melted, cooled and then ground by a jet mill grinder into a particle size of 5 20 microns to obtain a toner.  
  One part of the toner and 3 30 parts, preferably 5 10 parts, of iron powder (i.e. a carrier) were mixed.  
  The electrostatic latent image produced on an insulating layer by the electrographic method disclosed in Japanese Patent Publication No. 23910/1967 was developed with the above mentioned developing agent produced above by means of magnet brush technique to form a toner image.  
  Nine parts of Crystal Violet Lactone, 3 parts of Rhodamine Lactone, 3 parts of Malachite Green Lactone, 9 parts of leuco auramine and 40 parts of stearic acid were heated to melt, and added to parts of 10% aqueous solution of polyvinyl alcohol heated at 80C, to which 0.5 parts of emulsifier (trade mark: Dresinate X) was added and thereafter 40 parts of water was added to obtain the coating solution. After the coating solution was cooled, a paper was coated with the coating solution in the amount of about 7 g./m. to obtain a transferring paper.  
  The above mentioned toner image was transferred to the transferring paper and heated at about C to form black color in the portion where the toner image was transferred. The resultant copy was clear. The resultant image was not vanished even when rubbed strongly with an eraser.  
 EXAMPLE 10 Twenty parts of 4,4&#39;-cyclohexylidene bis(2-methyl phenol), 15 parts of stearic acid amide and 70 parts of styrene acrylic acid methyl ester copolymer (copolymerization molar ratio 6:4) were mixed and ground by a vibrating grinder. The mixture was sufficiently fused and cooled to solidify.  
  The solidified material was crushed by a hammer mill crusher and ground by a jet mill grinder into the particle size of l 50 microns, preferably 5 20 microns. One part of the fine powder (i.e. a toner), and 3 30 parts, preferably 5 10 parts, of iron powder (i.e. a carrier), were mixed.  
  The particle size of the carrier was 20 75 microns, preferably 25 50 microns. The carrier was charged negatively in the mixture of the carrier and the toner (i.e. the developing agent).  
  The photoconduetive layer composed of a vapor deposited selenium on an aluminium sheet was uniformly charged with a corona discharger, and then exposed to a light pattern to form an electrostatic latent image, which was developed by the above mentioned toner to form a toner image.  
  Twenty parts of Malachite Green Lactone and 40 parts of aluminium stearate were heated to melt and added to 150 parts of aqueous solution of polyvinyl alcohol heated at 80C, to which 0.5 parts of emulsifier (trade mark: Dresinate X) was added and thereafter 40 parts of water was added to obtain a coating solution. After the coating solution was cooled, a paper was coated with coating solution in the amount of about 7 g./m. and dried to obtain the transferring paper.  
  The above mentioned powder image was transferred to the transferring paper and heated at about 180C to form green color in the portion where the powder image was transferred. The resultant copy was clear. The resultant image was not vanished even when rubbed strongly with an eraser.  
 EXAMPLE 11 EXAMPLE 12 One part of an antioxidant (trade name: lrganox 565) and 1 part of an ultraviolet absorber (trade name: Tinuvin 328) were added to the coating solution used for the transferring paper of Example 1, and the other procedures were the same as those of Example 1. The resultant copy was clear blue. The copy was better in light resistance and had fogs less than that of Example 1.  
  The working examples of production of dry and liquid developing agents used for this invention and forming color image by using the above mentioned developing agent are illustrated below.  
 EXAMPLE 13 Sixty grams of 4,4&#39;-isopropylidene diphenyl, 272 g. of polystyrene (trade name: Piccolastic D-125 manufactured by Esso Co.), 31 g. of phenol resin (trade name: RB-lOO manufactured by Mitsui Toatsu Co.), 18 g. of stearic acid and 17 g. of Aerosil (trade name: No. 200  
 manufactured by DEGUSSA) were mixed and ground .obtain a toner. The toner of the particle size of 5 20 microns mixed with iron powder (the particle size of 20 40 microns) in the ratio of :85 to obtain a developing agent for magnet brush developer. Five grams of the toner of the particle size of less thatn 1.0 micron was added to lloflsopar H containing 0.015 g. of Pelex NB and dispersed with attritor to obtain a liquid developing agent.  
  The following composites (Examples 14 19) were treated by the procedures of Example 13 to produce a dry developing agent or a liquid developing agent.  
 Example 14 4,4&#39;-l3is (hydroxyphenyl) butyric acid 60 g.-  
 Polystyrene 270 g.  
 Phenolic resin 34 g.  
 Behenic acid 16 g.  
  Aerosil 17 g. Example 15 4,4&#39;-Bis (4-hydroxylphenyl) pentanoie acid 60 g.  
 Styrenc-acrylonitrile-indene copolymer (trade name: Piccoflex 520 manufactured by Esso Co.) 268 g.  
 Phenolic resin 32 g Myristic acid 18 g Aerosil 18 g. Example 16 4-Phenylphenol 60 g.  
 Polystyrene 270 g.  
 Phenol aldehyde copolymer resin 32 g.  
 Beryllium stearatc 18 g Aerosil 17 g. Example 17 4-Hydroxydiphenyl oxide 60 g.  
 Styrene-acrylic acid ethyl ester copolymer 272 g.  
 Phenolic resin 33 g Palmitic acid 17 g Aerosil 18 g. Example 18 4-Hydroxyaeetophenol 60 g Styrene-acrylonitrile copolymer 273 g Styrene-maleic acid anhydride copolymer 34 g Propionic acid amide 18 g Aerosil 18 g Example 19 4-Ter-butylphenol 60 g Styrene-butadiene copolymer resin 274 g Rosin modified maleic acid resin 32 g Enanthic acid amide 18 g Aerosil 18 g.  
 EXAMPLE 20 Sixty grams of 4,4-isopropylidene diphenyl, 270 g. of polystyrene, 32 g. of phenolic resin, 18 g. of lacceric acid and 18 g. of Aerosil were dissolved and dispersed in 31 of MEK, which was dispersed in ISI of lsopar 11 (containing Pelex NB) and furthermore dispersed finely by attritor disperser for 30 40 min. lsopar H was added to the fine dispersed solution to obtain the dispersed solution containing 5% (solid matter). The resultant dispersed solution was used as a developing solution.  
 EXAMPLE 21 Sixty grams of 4,4&#39;-bis (hydroxyphenyl) butyric acid, 270 g. of styrene-acrylonitrile copolymer, 33 g. of phenolic resin, 18 g. of stearic acid glycol and 18 g. of Aerosil were dissolved in 1 l of acetone and 2.5 I of MEK, and dispersed in 5 I of lsopar H. The dispersed materials were filtered under reduced pressure and were dispersed in 10 l of lsopar H again and then dispersed finely by attritor. The solution was diluted with lsopar H to 5% of solid content. The resultant solution was used as a developing solution.  
 EXAMPLE 22 The same composites as that of Examples 19 were treated by the same procedures as those of Example 21 to obtain the developing solution.  
 EXAMPLE 23 Sixty grams of4,4-isopropylidene diphenyl, 270 g. of polyethylene phthalate resin, 33 g. of phenolic resin. 18 g. of stearic acid and 18 g. of Aerosil were treated by the same procedures as those of Example 21. and the positive type developing solution was obtained.  
 EXAMPLE 24 Sixty grams of 4,4-bis (hydroxylphenyl) butyric acid, 273 g. of epoxy resin, 32 g. of phenolic resin, 18 g. of behenic acid ethyl and 18 g. of Aerosil were treated by the same procedures as those of Example 2 l and the positive type developing solution was obtained.  
 EXAMPLE 25 Sixty grams of 4,4-isopropylidene diphenyl, 270 g. of polyamide resin, 32 g. of phenol resin, 18 g. of melissic acid methyl and 18 g. of Aerosil were treated by the same procedure as those of Example 2l, and the positive developing solution was obtained.  
  The examples using dry and liquid developing agents are illustrated.  
 EXAMPLE 26 Ten parts of Crystal Violet Lactone, 2 parts of polystyrene, 40 parts of dimethyl formamide, 1 part of stearic acid and 1 part of diethyl diphenyl were mixed and dispersed by a ball mill for 24 hours. A commercial zinc oxide photosensitive paper was coated with the above mentioned solution by the air-knife method in the amount of the solution containing 0.4 g. of Crystal Violet Lactone. The photosensitive paper was subjected corona charging at 7 KV with corona discharger in a dark place and imagewise exposed and then was developed with the developing solutions used in Examples 13 25 and heated to fix. All of the obtained images were blue color.  
 EXAMPLE 27 The color forming agents (B) illustrated at the following table were used in place of Crystal Violet Lactone, and the other procedures were the same as those of Example 26. The resultant color images were as shown at following Table.  
 Forming color agent Forming color image Rhodamine B Lactone Red l-lbis(p-aminophenol)phthalan Violet Malachite Green Lactone Green 6-6&#39;-diaminospiro(phthalan-l,Q-xanthenc) Red 8&#39;-Mcthoxyindolinospiropyran Bluish black EXAMPLE 28 Thirty parts of Malachite Green Lactone (MGL) and 200 parts of 2.5% methanol solution of styrenemaleinic acid copolymer were mixed and ground by a ball mill, to which 300 parts of methyl ethyl ketone was added and mixed to obtain fine particles coated with resin of MGL. Thirty parts of 50% styrene-butadiene latex was added to the fine particles to obtain a coated solution. The paper treated with vinyl benzyl quaternary ammonium salt was coated with the coating solution to prepare a color forming sheet.  
  The CdS photosensitive plate disclosed in Japanese Patent Publication No. 23910/1967 was charged in +400 Volt and the charge was transferred to the above mentioned color forming sheet to charge in +100 volt. The color forming sheet was developed with the developing solution of Example 15 and heated to fix. The resultant copy was green.  
 EXAMPLE 29 EXAMPLE 30 Ten parts of Crystal Violet Lactone, 100 parts of polyvinyl alcohol (10% aqueous solution), 0.25 parts of emulsifier (trade name: Dresinate X) and 30 parts of stearic acid were mixed and finely dispersed by a ball mill for 24 hours to produce an emulsion. A high grade paper was coated by the emulsion at the speed of 25 m./min., and under air pressure of 500 mm. Aq. by an air-knife method. The coated paper was dried at 80 C. The paper used was a high grade paper of 52.3 g./m. The forming color image receiving sheet was coated with the solution containing 0.5 g./m. of Crystal Violet Lactone.  
  The electrostatic latent image was formed on a photosensitive member fundamentally composed of an electroconductive base plate, a photoconductive layer, and an insulating layer by the electrographic method disclosed in Japanese Patent Publication No. 24077/1970, that is, the surface of the insulated layer was uniformly charged positively when the photoconductive layer was N type and charged negatively when the photoelective layer was P type, and then was charged with alternating current corona discharger or direct current corona discharger having polarity opposite to that of the above charged. The electrostatic latent image was developed with the developing solutions of Examples 13 25 and was transferred to the above mentioned receiving image sheet and was heated at 180C to form a blue image.  
 Example 31 parts Rhodamine B Lactone l0 Stearic acid dodecyl amide 20 Polyvinylpyrrolidone l07r aqueous solution) Emulsifying dispersing agent (Ncopelcx-OS, trade name) 0.5  
  By using a composition of the above ingredients following the procedure of Example 30, there was obtained an image receiving sheet, and transferring of image was conducted to give red images.  
 Emulsifying dispersing agent (Neopelcx-OS. trade name) l.0  
  By using a composition of the above ingredients and following the procedure in Example 30, there was obtained a color forming image receiving sheet having a coating of 0.7 g./m. A developed image was transferred to the sheet and heated to 180C to produce a sharp violet image.  
 EXAMPLE 33 Ten parts of Crystal Violet Lactone was dissolved in 30 parts of diethyl diphenyl and then dispersed in an aqueous solution composed of a aqueous solution of gelatin (250 parts) and an emulsifying dispersing agent (Neopelex-OS, trade name) (one part) by using a supersonic dispersing machine. Thus, the oily drops of Crystal Violet Lactone were dispersed to form a particle of less than 0.5 microns. The resulting dispersion was applied to a triacetate film (150 microns in thickness) having a gelatin undercoating and dried at 55C to obtain a transparent film of 1.0 g./m.&#34;. To the resulting film was transferred a developed image and heated at 170C to produce a transparent blue image.  
 EXAMPLE 34 Ten parts of Rhodamine B Lactone was dissolved in 28 parts of diethyl diphenyl and then mixed with a solution of 10 parts of styrene-acrylonitrile copolymer in 100 parts of methyl ethyl ketone with stirring. The resulting solution was applied to a polyethylene terephthalate film subjected to a hydrophilizing treatment in a way similar to Example 30 to produce an image receiving sheet having the coating of 1.2 g./m.  
  To the image receiving sheet was transferred a developed image and heated at 170C to produce a transparent red image.  
 EXAMPLE 35 There were obtained images by developing with a dry developer in Examples 13 19 an electrostatic latent image produced by an electrophotographic method as described in Japanese Patent Publication No. 23910/1967, that is, positively charging uniformly a photosensitive member comprising a conductive base plate, a photoconductive material layer (e.g. CdS layer) and an insulating layer such as polyethylene terephthalate, applying charging of a polarity opposite to the primary charge or AC simultaneously with imagewise exposure to produce an electrostatic latent image followed by dry development, transferring the developed image to an image receiving sheet, then cleaning the photosensitive member and using the photosensitive member repeatedly.  
  The above-mentioned ingredients are mixed and dissolved and applied to an ethylene terephthalate film (Lumirror, trade name, supplied by Toray) in the thickness of 0.5 microns (when dried) by reverse coating to produce a transparent transferring sheet.  
  To the resulting transferring sheet was transferred the above-mentioned developed image and heated to produce a sharp and transparent blue copy.  
 EXAMPLE 36 There were obtained images by developing with a liquid developer in Examples 13 25 an electrostatic latent image produced by an electrophotographic method as described in Japanese Patent Publication No. 24077/1970, that is, positively charging uniformly a photosensitive member comprising a conductive base plate, a photoconductive material layer (e.g. CdS layer) and an insulating layer such as polyethylene terephthalate, applying charging of a polarity opposite to the primary charge or AC simultaneously with imagewise exposure to produce an electrostatic latent image followed by wet development, transferring the developed image to an image receiving sheet, then cleaning the photosensitive member and using the photosensitive member repeatedly.  
 Crystal Violet Lactone Silicon rcsin (KR-21 l, trade name, supplied by Shinctsu Kagaku) 5 g. Dimethyl formamidc EXAMPLE 37 Following the procedure of Example 36 except that a transferring sheet containing the color forming agent (B) as shown below is used in place of that containing Crystal Violet Lactone, there was obtained a sharp and transparent color copy.  
 Color forming agent (B) in a transferring Color of image sheet Rhodamine B Lactonc Red l, l -Bis( p-aminophenyl )phthalan Violet Malachite Green Laetonc Green 6,6&#39;-Diaminospiro( phthalanl ,9-xanthcne) Red 8&#39;-Mcthoxyindolinospiropyran Bluish black Some examples using an organic photoconductive material are shown below.  
 EXAMPLE 38 To a support composed of polyethylene terephthalate film microns in thickness) having a gelatin undercoating was applied a polymer of quaternary ammonium salt (CF-261, trade name. supplied by Calgon Corp.) in an amount of 3 6 g./m. (solid matter) as a conductive layer followed by drying sufficiently. To the EXAMPLE 51 The organic photoconductive film obtained in Example 38 was subjected to corona charging of 6 KV and surface f the resulting cfmducm&#39;e layer flppliefl imagewise exposure to form an electrostatic latent im- 5% solution of poly-9-v1nylcarbazole (sensitized with age Crystal Violet) n monochlorobenzene by roll to form A liquid developer was prepared by the following a photoconductrve film. To the surface of the photopmcedum conductive film of 5 8 g./m. thus obtained was applied a color forming agent (B) as shown below. Crystal Violet Lactone (C.V.L.) was dissolved in dimethylformamide to form a 7% solution. 100 Ml. of the result- 4 4&#39;-lsopropyli dene diphenyl 60 g. mg solution was mixed with l0 ml. of a 5% solub1932 iplcivlflstlc 11135- lmdc name 771 I supp to y sso g. tion of poly 9-vmylcarbazole 1n rnonoehlorobenzene Phenolic min (RBJOQ suppncd and was applied to the above-mentioned photoconduc- 15 m a l 31 g 2 ethy arae ate l8 g trve film in an amount of 1.5 3.0 g./m. by roll fol Acmsil (NO. trade numc suppcd by lowed by drying to produce an electrophogotraphlc DEGUSSA) l7 g photosensitive member having an organic photoconductive layer containing the color forming agent (B).  
  EXAMPLES 39 50 A composition of the above mentioned ingredients Materials listed in Table 4 were used and the procewas mixed and ground for 24 hours by a ball mill, dure of Example 38 was repeated to form organic phosufficiently melted and kneaded by a roll mill. cooled, toconductive photosensitive members. then roughly ground to about 1 mm. in size by a ham- Table 4 Organic Color forming Example Support base C onduetive resin photoconduetive main agent material 39 The same as in The same as in Poly-3 fJ-dibromo-9- Crystal Violet Example 38 Example 38 vinylcarbazol el Lactone 40 H H 41 Quaternary ammonium salt polymer (ECR-34, trade name, 2 supplied by Dow Chemical) 42 Triacetate film having gelatin undereoating Poly-3.6-dmnro-9- I00 microns in vinylcarbazole thick) 43 Poly-3.6-diiodo-9- vinylcarbazole 44 The same as in Poly-3,6-dibromo-9- Malachite Example 38 vinylcarbazolc Green Lactone 45 The same as in Poly-3,6-dichloro- Rhodamine Example 38 9-vinylcarbazole Laetone 46 The same as in The same as in Poly-3,6-dinitro- Leueo Example 38 Example 38 9-vinylcarbazole auramine 47 l Malachite v Green Lactone 48 2 Rhodamine Lactone 49 Poly-9-vinylcarbazole 50 Poly-3,6-dibromo- Leuco 9-vinylcarbazole auramine /NH NH\ C l C --CH CH -O 1 2 2 N I N EXAMPLE 52 The organic photoconductive film obtained in Example 39 was subjected to corona charging of 6KV and imagewise exposure to form an electrostatic latent image.  
  A liquid developer was prepared by the followin procedure.  
 4.4&#39;-Bis(hydroxydiphenyl)hutyric acid 60 g. Polystyrene (Piccolastic D-l25. trade name) 270 g. Phenolic resin (RB-I00. trade name.  
 supplied by Mitsui-Toatsu) 34 g. Caproic acid anilide 16 g. Aerosil l7 g.  
  A liquid developer was obtained by using the above components following the procedure of Example The electrostatic latent image was developed by the resulting liquid developer to form a colorless image on the organic photoconductive layer and heated and melted to product a transparent blue visible image.  
 EXAMPLE 53 The organic photoconductive film obtained in Example 40 was subjected to corona charging of 6KV and imagewise exposure to form an electrostatic latent image.  
  A liquid developer was prepared by the following procedure.  
 4,4&#39;-Bis(4-hydroxyphcnyl )pentanoic acid Styrenc-acrylonitrile-indcnc copolymer 268 g. Phenolic resin 32 g. Myristic acid dodceyl amide 18 g. Aerosil l8 g.  
  Following the procedure of Example 51, the above mentioned components were made into a liquid developer.  
  The electrostatic latent image was developed by the resulting liquid developer to form a colorless image on the organic photoconductive layer and heated and melted to produce a transparent blue visible image.  
 EXAMPLE 54 The organic photoconductive film obtained in Example 41 was subjected to corona charging of -6KV and imagewise exposure to form an electrostatic latent image.  
  A developer was prepared by the following procedure.  
 4-Phenyl phenol Polystyrene -Continued Phenol aldehyde resin 32 g. Diphenyl phthalate l8 g. Aerosil l7 g The above mentioned components were mixed and ground for 25 hours by a ball mill, sufficiently melted and kneaded by a roll mill, cooled and roughly ground by a hammer mill and then pulverized by a jet mill and then classified to obtain powders of 5 20 microns in size and the powder thus classified was used as a toner. The resulting toner was mixed with 5 6% of carrier iron powder (200 400 mesh) to produce a dry developer. The electrostatic latent image on the organic photoconductive layer was developed by the resulting developer according to magnet brush development.  
  The colorless image formed on the organic photoconductive layer was heated and melted to produce a transparent blue visible image.  
 EXAMPLE 55 The organic photoconductive film obtained in Example 42 was subjected to corona charging of -6KV and imagewise exposure to form an electrostatic latent image.  
  A developer was prepared by the following procedure.  
 4-Hydroxydiphcnyl oxide 60 g. Styrene-acrylic acid ethyl ester eopolymer 272 g. Phenolic resin 33 g. Lead palmitate 17 g. Aerosil 18 g.  
  Following the procedure of Example 54, a developer was obtained by using the components.  
  The electrostatic latent image was developed by using the resulting developer according to magnet brush development, and the resulting colorless image on the organic photoconductive layer was heated and melted to produce a transparent blue visible image.  
 EXAMPLE 56 The organic photoconductive film obtained in Example 43 was subjected to corona charging of 6KV and imagewise exposure to form an electrostatic latent image.  
  A developer was prepared by the following procedure.  
 4-Hydroxyacetophenol 60 g. Styrcne-acrylonitrile copolymer 273 g Styrene-maleic anhydridc copolymer 34 g. Ethyl lacccrate 18 g. Aerosil 18 g.  
  Following the procedure of Example 54, a developer was obtained. The electrostatic latent image was developed by the resulting developer according to magnet brush development. The colorless image formed on the organic photoconductive layer was heated and melted to produce a transparent blue visible image.  
 EXAMPLE 57 The organic photoconductive film obtained in Exammer mill and further finely divided by a pulverizer of ing. dispersed again in 10 liters of an insulating liquid, air-jet pulverization type (pulverizing pressure 6 7 and finely dispersed by attritor dispersing machine. l(g./cm. and feed 3 Kg./hour). The resulting finely di- Further, the resulting dispersion was diluted to 5% vided powders were classified by a wind classifier and (solid matter) to produce a developer.  
 powder of less than 1.0 micron was employed as a 5 The resulting liquid developer was used to develop ple 44 was subjected to corona charging of 6KV and the electrostatic latent image. The colorless image imagewise exposure to form an electrostatic latent imformed on the organic photoconductive layer was age. heated and melted to produce a transparent yellowish A llqUld developer was prepared by the following red visible image. procedure. It)  
 EXAMPLE 60 g-t-Butyltphcrjol 1 g. The organic photoconductive film obtained in Examtyrcneuta tent: copoymcr 274 Rosin-modified malcic acid resin 32 P 47 7 Subjected to corona chdrgmg 6KV i Ethylene g|yc0l dibcnmutc 1g imagewise exposure to form an electrostatic latent im- Aerosil [8 g. l5 age Following the procedure of Example 54. there was A developer was prepared by the following P obtained a developer, which was used to develop the dune electrostatic latent image. The colorless image produced on the organic photoconductive layer was heated and melted to produce a transparent green visi- 4,4&#39;-lsopropylidcnc diphcnyl 60 g.  
 ble image. Polyester resin 270 g. Phenolic resin 33 g, Lead laurate l8 g.  
 EXAMPLE 58 Aerosil l8 g,  
  The organic photoconductive film obtained in Example 45 was subjected to corona charging of 6KV and imagewise exposure to form an electrostatic latent im- The above mgredlems were treated a way slmllar to Example 59 to produce a liquid developer, which age.  
 A liquid developer was prepared by 111,3 following was used to develop the above mentioned electrostatic procedurg latent image. The colorless image formed on the organic hotoconductive la er was heated and melted to p y l l 4&#39;44SOpmpylidcnc p y 60 g produce a transparent green visible image.  
 Polystyrene 270 g.  
 Ehenolic resin 32 g. EXAMPLE 61 and {g g 35 The organic photoconductive film obtained in Example 48 was subjected to corona charging of 6KV and The above components were dissolved and dispersed imagewise exposure to form an electrostatic latent imin 3 litres of MEK and then dispersed in 15 litres of an age.  
 insulating liquid (lsopar H) and then finely dispersed A developer was prepared by the following procefor 30 min. by attritor dispersing machine. To the 40 dure.  
 resulting fine dispersion liquid was added further the above-mentioned insulating liquid to produce a 5% (solid matter) dispersion liquid, which was used as a g,4-Bis(hy droxyphcnyl) butyric acid 3(3) g. poxy rcsin g. developer; Phenolic resin (RB-100) 32 g.  
 The resulting liquid developer was used to develop Melissic acid 18 g.  
 the above-mentioned electrostatic latent image. The Acrosl&#39; 200) colorless image formed on the organic photoconductive layer was heated and melted to produce a transpar- The above ingredients were treated in a way similar ent red visible image.  
 to Example 54 to produce a dry toner, which was used EXAMPLE 59 to develop the electrostatic latent image. The colorless image formed on the organic photoconductive layer The organic photoconductive film obtained in Examwas heated and melted to Produce a transparent Ted ple 46 was subjected to corona charging of 6KV and Visible imageimagewise exposure to form an electrostatic latent im- EXAMPLE 62 A liquid developer was prepared by the foll i The organic photoconductive film obtained in Exam procedure. ple 49 was subjected to corona charging of -6KV and imagewise exposure to form an electrostatic latent image. 4,4-Bis(hydroxyphcnyl) butyric acid 0 A developer was prepared by the following proce- Styrene-acrylonitrile copolymcr 270 g. d Phenolic resin 33 g. Glycerol palmitatc l8 g. Aerosil l8 g.  
  65 4.4&#39;-lsopropylidcnc diphcnyl 60 g. Th Poly-amide 270 g. e above materials were dlssolved in l liter of acephcnpjic Yes, 32 tone and 2.5 liters of M EK and dispersed in 5 liters of Capnc acid anllldc l8 san insulating liquid (lsopar H), filtered once by suck- Aerosil The above materials were treated in a way similar to Example 54 to obtain a dry developer, which was used to develop the electrostatic latent image. The colorless image formed on the organic photoconductive layer was heated and melted to produce a transparent red visible image.  
 EXAMPLE 63 The organic photoconductive film obtained in Examples 39 50 was subjected to corona charging of 6KV and imagewise exposure to form an electrostatic latent image.  
  Then, the electrostatic latent image was developed by a liquid developer as used in Example l The colorless image produced on each organic photoconductive layer was heated and melted, and a transparent blue, green, red and yellowish red visible image was obtained when an organic photoconductive film of Examples 39 43, Examples 44 and 47, Examples 45, 48 and 49, and Examples 46 and 50, respectively.  
  In the following, there are given examples of a printing method using the electrophotographic method according to the present invention.  
  The above materials were mixed and ground for 24 30 hours by a ball mill, sufficiently melted and kneaded by a roll mill, cooled, roughly ground to a size of about l mm. by a hammer mill, and further pulverized by a pulverizer of air-jet type. The resulting finely divided powders were classified by a pressure classifier to select fine powders of less than microns in size, which were then used as a toner. Iron powder (as carrier) was mixed with the toner in an amount of 8 50 parts, preferably, 10 parts, per one part of toner. The iron powder was of 20 75 microns, preferably, microns, in size. There was used a printing paper produced by coating a paper with Crystal Violet Lactone (CVL) together with an appropriate binder.  
  The whole surface of a photoconductive member comprising zine oxide and a binder resin was subjected to negative charging, exposed to a light and shadow pattern and passed through a developing device. The toner particles attached to a negatively charged portion. Toner image on a zinc oxide paper as a master sheet was transferred to a printing paper having a coating of Crystal Violet Lactone (CVL) by heating and pressing using a device as shown in FIG. 6 to produce a blue image on the printing paper. The above procedure was repeated and 20 sheets of good copy were obtained. The twentieth copy is as good as the first copy.  
 EXAMPLE 65 There were used the same developer and image receiving sheet as those in Example 64. A toner image was produced on a rotary drum having a selenium layer Example 66 parts 4.4&#39;-Bis(hydroxyphenyl) butyric acid 22 Phenolic resin 9 Styrcnc-butadienc copolymer resin Stcaric acid 2.5 Aerosil 6 Following the procedure of Example 64, a toner was prepared from the above components.  
  The resulting toner was dispersed in lsopar H (trade name, supplied by ESSO Standard Oil) to produce a liquid developer. An electrostatic latent image (mirror image of the original image) was produced on a ZnO paper by the same method as Example 64 comprising negatively charging and exposing and developed in a liquid developer. The resulting toner image on the ZnO paper was transferred to a transferring paper composed of a printing paper having a Rhodamine Lactone (RL) coating as in Example 64. In a way similar to Example 64 there was obtained a good red colored image. Further, 20 sheets of good copy were obtained.  
  The above ingredients were treated in a way similar to Example 64 to produce a toner.  
  pans Malachite Green Lactone (MGL) 50 Stcaric acid 50 Polyvinylalcohol (PVA) 400 Water 1200 Emanone (trade name, supplied by Kao Sekken) l3 Polyvinylpyrrolidone (PVPK-30, trade name) 2 The above components were coated on a paper to produce a printing paper. The coating is effected in such a way that the amount of Malachite Green Lactam was 1.0 g./m.  
  In a way similar to Example 64, there was obtained 15 sheets of green image copy.  
 EXAMPLE 68 A photosensitive member composed of a polyester film wound on a photoconductive selenium (as an insulating film) was charged in a known method and selectively discharged to form a latent image.  
 parts 4-Phenyl phenol 20