Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G7/00—Selection of materials for use in image-receiving members, i.e. for reversal by physical contact; Manufacture thereof
  • G03G7/0006—Cover layers for image-receiving members; Strippable coversheets
  • G03G7/002—Organic components thereof
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G7/00—Selection of materials for use in image-receiving members, i.e. for reversal by physical contact; Manufacture thereof
  • G03G7/0006—Cover layers for image-receiving members; Strippable coversheets
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G7/00—Selection of materials for use in image-receiving members, i.e. for reversal by physical contact; Manufacture thereof
  • G03G7/0006—Cover layers for image-receiving members; Strippable coversheets
  • G03G7/002—Organic components thereof
  • G03G7/0026—Organic components thereof being macromolecular
  • G03G7/0046—Organic components thereof being macromolecular obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds

Definitions

• the present invention relates to an imageable transparent film for use with an overhead projector and in particular, to a toner imageable transparent film preferred for color toner imaging and projection of a high quality color image.
• reprographic processes are now used for forming color images on transparent films intended for projection via an overhead projector (hereinafter "OHP").
• OHP overhead projector
• black or colored toner is deposited patternwise onto the transparent film by using a reprographic apparatus, commonly called a copier, commercially available from a variety of manufacturing companies.
• the toner imaged film for projection prepared accordingly in a copier suffers from lack of clarity in the projected image. Particularly when a color toner image is applied on the transparent film, dark blurred areas in the image are directly observable when the image is projected on the screen.
• JP-A- 61-36756 and 61-36762 disclose a process comprising overlaying a thin film to a toner image deposited onto a transparent film; and removing the thin film after melting the toner image by applying heat and pressure. Transparency of color image projection is improved by the above described process, however, an additional apparatus for melting the toner is required, and the process is more complicated.
• JP-A- 2-38090 discloses a process comprising overlaying a thermoplastic resin film 20 ⁇ m or less in thickness, preferably 10 ⁇ m or less, on a toner image deposited onto a transparent film, and laminating the overlapped resin films under heat and pressure.
• the thermoplastic resin film must have a higher softening point than the toner. This process however does not provide remarkable improvement in transparency or clarity of a toner image projected on a screen, and is a more complicated and expensive process using two film layers for each image desired.
• a transparent clear projection image is not provided by the prior art procedure is believed to be that the toner image which is formed using a copier has a rough surface. Light incident on the transparent film bearing such an image is scattered and diffused by the rough surface of the toner image, and the amount of light passed through the toner image is decreased. As a result, a dark blurred image is projected on the screen.
• the present invention overcomes the above described prior art problems, and provides a toner imageable film which is imageable on commercial copiers, and provides a transparent clear projection image on the screen.
• the present invention provides a toner imageable film comprising a transparent film substrate bearing on one major surface thereof a toner receiving layer, wherein the toner receiving layer has a lower softening point than the toner with which it is imaged.
• the transparent film substrate employed in the present invention is not limited, but includes any transparent material generally used for imageable sheets. Materials having good transparency, heat-resistance, strength and rigidity are preferred. The preferred thickness of such materials is from 25-175 ⁇ m thick. Specific examples of suitable materials include polyesters such as polyethylene terephthalate and cellulose esters.
• the toner receiving layer of the present invention comprises a resin having good transparency and good compatibility with a toner resin.
• a resin having an approximately equal refractive index with a toner resin is preferably employed, since such a resin does not inhibit light transmittance of the toner image.
• the resin employed for the toner receiving layer must have a lower Softening point than the toner.
• a softening point of 100°C or less, more preferably from 40-80°C, since most of toners generally employed at the present reprographic art have softening points ranging from approximately 8°C to 120°C, preferably 80 °C to 120 °C.
• softening point means a temperature at which a rigid resin softens to a rubber-like state, or at which crystal portions of the resin molecules melt.
• the softening point may be determined using a ring and ball test method or a needle intrusion test method.
• resins employed in toner receiving layers of the invention include phenoxy resins, cyanate resins, polyester resins may be employed in the present invention.
• Epoxy resins having a number average molecular weight of not more than 2000 are preferred resins. Since such an epoxy resin is sensitive to heat, it immediately melts upon heating and easily engulfs a toner particle therein, resulting in a toner image with a more smooth and level surface.
• these resins include "EPIKOTE 1001", having a molecular weight of about 900, and a softening point of 64°C, "EPIKOTE 1003”, having a softening point of 51.2°C and "EPIKOTE 1004", having a molecular weight of 1600 and a softening point of 59.8°C, all of which are commercially available from Shell Chemical Co.
• epoxy resins above described may become turbid under low temperature conditions, this may be overcome by controlling the thickness of the toner receiving layer or by employing a low molecular weight diluent such as ethylene glycol and propylene glycol.
• additives such as antioxidants, viscosity controlling agents and UV absorbers may be included in a resin employed in the present invention, in such amounts that the additive will not interfere with required features of the toner receiving layer such as transparency and softening point.
• UV absorbers are preferred additives because in recent years, toner particles have been finely ground in order to provide higher resolution and improved transparency to a toner image. Such fine toner particles may cause light susceptibility of the toner image.
• the use of a toner receiving layer including a UV absorber can remarkably improve light resistance of the toner image against ambient light or irradiation from the OHP light source.
• a UV absorber is employed in an amount 0.005-0.10, preferably 0.05-5 parts by weight based on 100 parts by weight of a resin for the toner receiving layer.
• Useful toners are not limited, but include conventional thermoplastic toners known to those skilled in the art.
• toners formed from styrene-(meth)acrylic acid copolymers, styrene-acrylate copolymers, bisphenol-A epoxy resins and polyester resins may be employed with imageable sheets of the invention.
• Average particle size of the toner varies, but preferably is in the range of about 7-30 ⁇ m, for good resolution of the resulting toner image.
• colored toners such as cyan, magenta or yellow provides a color toner image useful in the present invention.
• a toner imageable film of the present invention is produced by applying a toner receiving layer onto a major surface of a transparent film substrate.
• the toner receiving layer can be applied by various coating procedures which include, for example, Mayer bar coating followed by drying the coating or knife coating.
• Dry thickness of the toner receiving layer is preferably more than 50% of the toner particle size. If the layer thickness is less than 50% of the toner particle size, the image surface may not be smooth enough. Since an average particle size of toner generally employed is in the range of 6-7 ⁇ m, thickness of the toner receiving layer is preferably at least 3 ⁇ m, more preferably at least 10 ⁇ m.
• Maximum thickness of the toner receiving layer is preferably up to 100 ⁇ m, more preferably up to 75 ⁇ m.
• a toner imaged film of the present invention which can provide a transparent clear projected image may be produced by the following process.
• a thermoplastic toner is imagewise deposited onto a toner receiving layer surface of an imageable film of the present invention in the copier.
• the toner may be black or colored.
• the resulting film bearing a toner image thereon is then passed through the heat pressure roll of the copier to engulf the toner image in the resin of the toner receiving layer, and "fix" the image.
• an "unfixed” image can be removed from the copier, and separately heat pressed, although this is less desirable.
• the heat pressure roll preferably has a maximum temperature higher than the softening point of the toner receiving layer and lower than the softening point of the toner.
• the temperature of the heat pressure roll is lower than the softening point of the toner receiving layer, toner particles will not be properly enveloped and covered by the toner receiving layer by pressing, and the surface of the toner image may still be too rough. If the temperature of the heat pressure roll is higher than the softening point of the toner, the toner will flow from the desired position, and a blurred toner image results.
• the solution for the toner receiving layer was then applied to a surface of the polyethylene terephthalate (PET) film having 80 ⁇ m (4 mil) thickness using a #10 Mayer bar, and the sheet was then dried for 10 minutes at 65° C.
• PET polyethylene terephthalate
• Red and blue toner images were independently formed on the resulting transparent film by using a "KONICA 8010 MULTI COLOR COPYING MACHINE" available from Konica K.K. Each transparent film bearing a toner image was heat-pressed by passing through the reproductive apparatus again at a copying mode.
• the toner employed was a pigmented bisphenol-A epoxy resin having an average particle size of about 19 ⁇ m and a melting point of 100-105° C.
• red and blue toner images were independently formed on PET film having no toner receiving layer thereon by using the above identified copier.
• Red and blue toner images were independently formed on PET film having no toner receiving layer thereon by using "KONICA 8010 MULTI COLOR COPYING MACHINE" available from Konica K.K. as described in Example 1.
• a polyester film of 10 ⁇ m thick was overlaid atop the resulting toner image.
• the overlapped film was then laminated by using a laminator available from Ushio K.K. to melt the toner between the two films. Transfer speed of the laminator was set at 9.5 mm/sec, and laminating temperatures were set at 190° C and 130° C, respectively.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Developing Agents For Electrophotography (AREA)
• Combination Of More Than One Step In Electrophotography (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=17973416

Family Applications (1)

Country Status (2)

Cited By (3)

Families Citing this family (6)

Citations (4)

• 1993
  • 1993-12-08 JP JP30780393A patent/JPH07199515A/ja active Pending
• 1994
  • 1994-12-08 EP EP94119450A patent/EP0657782A1/fr not_active Ceased

Patent Citations (4)

Non-Patent Citations (4)

Also Published As

Similar Documents

Legal Events