Claims
- 1. An apparatus for fixing a visible pigment image to a sheet of support material comprising:
- a first heated body having a surface thereof;
- a layer of material formed on said surface of said body;
- a layer of elastomeric material formed on said surface;
- a second body having a surface thereof;
- said first and second bodies positioned for providing contact between surfaces of said layers at a nip formed therebetween;
- means for imparting motion to said bodies for providing that a sheet of material introduced to said nip between said bodies is transported through said nip;
- a source of a binder material for fixing visible image on a sheet;
- means for contacting a surface of said elastomeric material with said binder in a fluid state; and
- means for introducing and transporting through said nip an image support sheet, said support sheet having an image formed thereon by a material consisting essentially of a colorant and wherein an image surface of said support sheet is positioned during transit through said nip for coating said imaged surface with said binder material;
- wherein said means for contacting said elastomeric material with said binder comprises a heat applicator body, means for transporting said body in contact with said elastomeric material, and means for contacting said applicator body with said binder material.
- 2. The apparatus of claim 1 wherein said elastomeric material comprises a silicone elastomer.
- 3. The apparatus of claim 1 wherein said layer of material formed on the surface of said second body comprises an elastomer overcoated with a fluorocarbon resin.
- 4. The apparatus of claim 1 including means positioned in contact with said first body for removal of residual contaminant particles from said elastomeric surface as said surface is advanced away from said nip.
- 5. The apparatus of claim 4 including means for removing residual particles from the surface of said layer of said second body when said surface is advanced away from said nip.
- 6. An apparatus for fixing a visible pigment image to a sheet to support material comprising:
- a first heated body having a surface thereof;
- a layer of elastomeric material formed on said surface;
- a second body having a surface thereof;
- a layer of material formed on said surface of said body;
- said first and second bodies positioned for providing contact between surfaces of said layers at a nip formed therebetween;
- means for imparting motion of said bodies for providing that a sheet of material introduced to said nip between said bodies is transported through said nip;
- a source of a binder material for fixing visible image on a sheet;
- means for contacting a surface of said elastomeric material with said binder in a fluid state; and
- means for introducing and transporting through said nip an image support sheet, said support sheet having an image formed thereon by a material consisting essentially of a colorant and wherein an images surface of said support sheet is positioned during transit through said nip for coating said imaged surface with said binder material;
- means positioned to contact with said first body for removal of residual contaminant particles from said elastomeric surface as said surface is advanced away from said nip;
- means for discharging an accumulated electrostatic charge on the surface of said layer of said second body.
Parent Case Info
This is a division, of application Ser. No. 556, 065, filed 03/06/75, now abandoned.
This invention relates to a method and an apparatus for fixing images on a support material. The invention relates more particularly to an improved method and apparatus for applying a binder material to an image bearing surface.
In various reproduction systems, an image formed on a support surface is generally fixed to the surface in order to inhibit smudging of the image and to assure its relative permanency. In the xerographic processing arts, for example, an electrostatic latent image is formed on a photoreceptor and is developed by contacting the photoreceptor with a developer material which includes a colorant. The developed image is then transferred to a support sheet for permanent recording. In general, slight contact with the image in this state will cause movement of the toner particles on the support sheet, smudging, and distortion of the image. Therefore, it is customary as a step in the reproduction process to bond or fix the image to the support sheet.
One widely employed technique for effecting this bonding is to provide a particulate toner material which comprises a mixture of a colorant and a resin which can be thermally or solvent softened. As thermal energy or solvent vapor is applied to the toner material in image configuration on the support sheet, the toner softens and tends to become fluid; the contact points between the developed image and the support sheet are broadened; and, the softened toner particles flow together and into the paper fibers. Fixing of the image is also at times enhanced by the simultaneous application of pressure to the support sheet. The softened image then sets upon removal of heat or solvent vapor to provide a relatively permanent image record.
At times it is not feasible to provide a developer material containing a fixing resin because of limitations imposed on the physical characteristics of the materials by the process or by the use of a process which cannot accommodate such a material. In the former case, for example, when the image is formed of pigment particles that are relatively stable with respect to the heat or solvents, then the component used to effect fixing must be introduced after the image is formed. This is also true when fixing resins are employed whose softening temperature or solubility is impractical to employ for the application at hand. An example of a process which provides a pigmented image and which is not generally adapted to accommodate a blend of a heat or vapor softenable resin with the pigment is the photoelectrophoresis process for reproducing images.
The simplest image-forming material is one in which the developer material consists of pure pigments. Typical pigments that have been used to form xerographic images are cadmium yellow, chrome yellow, pulvarized charcoal, and zinc oxide. However, most pigments have no physical property that can be utilized for causing them to adhere to a substrate such as paper. In those situations wherein a mixture of pigment and fixing agent cannot be employed, then fixing of the image has been provided subsequent to the imaging process by applying a fixing vehicle to the entire imaged surface. These techniques include aerosol spraying of the image support body with a clear acrylic; juxtopositioning a polyethylene coated sheet with respect to the support body and applying heat to the sandwich thereby causing the polyethylene to flow to the image support sheet and to fix the image to the support body; and, contacting the image support body with a gelatin capsule coated paper which is initially softened with water.
While these techniques are effective in providing the desired fixing, they do not lend themselves to a continous process for fixing images on a carrier or on a support body such as paper or other plastic film substrate. Furthermore, the pigments exhibit a tendency to stain bodies with which they come into contact. This staining characteristic is undesirable and is believed due to electrostatic particle transfer combined with surface forces associated with moisture and other wetting characteristics. As a result, apparatus components such as transfer rollers are stained and deleteriously affect subsequent images which are formed.
Accordingly, it is an object of this invention to provide an improved method and apparatus for fixing an image formed by a colorant on a support body.
Another object of the invention is to provide an improved method and apparatus for providing continuous fixing of images formed by a colorant.
In accordance with features of the method of this invention, a colorant image is fixed on a support material by heating a binder material to a fluid state, contacting a transport surface at a higher temperature with the binder material, transporting the heated surface and the supported binder material to a nip formed between the binder transport surface and an adjacent pressure contact surface which is transported in moving engagement with the binder transport surface, and transporting a substrate bearing a colorant image through the nip formed by contact beneath the surfaces whereby the binder material is deposited on the image support material and is fixed thereto.
In accordance with features of the apparatus of this invention, an apparatus for fixing an image to a sheet support material comprises a first body having an outer surface thereof, a layer of material formed on said outer surface, means for heating said body to a predetermined temperature, a second body having an outer surface thereof, a layer of material formed on said surface of said second body, said first and second bodies positioned for providing contact between surfaces of said layers at a nip formed therebetween, means for imparting motion to said bodies, and means for applying a binder material to said layer of said first body for transport to said nip whereby a surface of sheet material introduced to said nip is transported therethrough by the motion of said body and a surface thereof adjacent to said surface of said first body is coated with said binder material.
US Referenced Citations (4)
Divisions (1)
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Number |
Date |
Country |
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556065 |
Mar 1975 |
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Patent Grant
4063530
