Stock material or miscellaneous articles – Composite – Of polycarbonate
Reexamination Certificate
2000-01-24
2002-02-26
Kiliman, Leszek (Department: 1773)
Stock material or miscellaneous articles
Composite
Of polycarbonate
C428S195100, C428S206000, C428S327000, C428S336000, C428S402000, C428S419000, C428S518000, C428S520000, C430S281100, C430S286100
Reexamination Certificate
active
06350522
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition for forming an image receiving layer and a polymer film for copying having the image receiving layer formed using the composition, and more particularly, to a composition for an image receiving layer capable of forming an image receiving layer having excellent toner adhesion properties, excellent antistatic properties, a low coefficient of friction, excellent anti-blocking properties and a pleasing appearance, and a polymer film for copying formed using the composition.
2. Description of the Related Art
In order for an overhead projector (OHP) to be used in an actual state, first, an image such as characters or pictures should be first formed on a transparent or semi-transparent polymer film using a copier.
As is well known, in a conventional electrophotographic photocopier, a toner image is formed in five steps as follows.
(1) A drum coated with a photoconductive material such as selenium passes under a series of corona discharge shims in a dark room so that the surface of the drum is positively or negatively charged electrostatically.
(2) The charged drum is exposed via a lens system having a reproduced image to form an electrostatic latent image on the surface of the charged drum, that is, charges on an exposed region of the drum are dispersed through a conductive support member while charges on an unexposed region of the drum remain largely intact on the surface of the drum to form the electrostatic latent image.
(3) When oppositely charged toner particles are brought into contact with the surface of the drum, the toner particles on the charged area of the surface of the drum cling thereto by electrostatic attraction.
(4) When an image receiving polymer film passes between the drum and a transfer corona discharge shim, the toner particles are transferred to the polymer film.
(5) The transferred toner particles are fused to the polymer film by application of heat and/or pressure.
There exist known numerous kinds of copiers capable of forming an image on a transparent or semi-transparent polymer film by the above-described electrophotographic copying process. The polymer films used for these copiers must be essentially equipped with desirable characteristics, including toner adhesion properties, excellent antistatic property for suppressing copy degradation during continuous copying, due to static charge buildup on a film substrate, a low friction coefficient for minimizing multiplex transfer (that is, a phenomenon in which multiple overlapping films may be simultaneously transferred) and jamming (that is, a phenomenon in which a copying process is interrupted when a film jams into a copier) during continuous copying, and an anti-blocking property, which is for avoiding multiplex transfer or jamming when a film is to be kept for a long time or during a continuous copying process.
The following prior art U.S. patents were provided: U.S. Pat. No. 3,854,942, which discloses that a mixture of a vinyl chloride-acetate copolymer and an acrylic resin is coated on a polymer film substrate; and U.S. Pat. No. 4,370,379, which discloses that a mixture of an acrylic resin and a polyester is coated on a polymer film substrate. However, both technologies have a limit in toner adhesion properties. In particular, in both technologies, the toner adhesion properties are not satisfactory during a high-temperature continuous copying process. Even in the case where polyvinyl acetate, polymethyl methacrylate and a polyester are appropriately combined, as taught in U.S. Pat. No. 4,873,135, the adhesion properties do not exceed a constant level with respect to various kinds of toners. Thus, in this case, a separate primer layer must be formed, which is a cumbersome task.
In the case where a terpolymer of vinyl halide, a vinyl ester of a saturated aliphatic carboxylic acid and functional group-containing unsaturated termonomer is used as an image receiving layer, as disclosed in U.S. Pat. No. 4,891,285, or in the case where a coating composition comprised of a mixture of (a) non ionic celluloses or blends thereof; (b) ionic celluloses or blends thereof; (c) poly(alkylene oxide); and (d) a noncellulose component, as disclosed in U.S. Pat. No. 5,137,773, the antistatic effect is poor so that polymer films accumulating on a tray after a continuous copying process, may cling to one another by static electricity, and thus, not to be put in order. In Japanese Laid-Open Publication No. sho 51-34734; U.S. Pat. Nos. 3,854,942; 4,071,362; 4,415,626; and 4,489,122, there is disclosed a method for preventing the generation of static electricity using an antistatic agent. However, the use of an antistatic agent having a marked mobility as the time passes causes the following problem. That is, toner adhesion properties are deteriorated so that a loss in the image may be caused during handling of the copied polymer film. Also, during stacking, the antistatic agent may be transferred to an adjacent polymer film so that an uncopied region may be produced. Further, since the antistatic agent does not have sufficient miscibility with polymer resin, it cannot exert an antistatic effect, which makes it impossible for the antistatic agent to prevent multiplex transfer or jam.
U.S. Pat. Nos. 4,480,003 and 4,585,730 are directed to improvements in antistatic properties and changes in antistatic property over time, by using a conductive polymer. However, the conductive polymer used is expensive and a large amount thereof must be injected compared to the antistatic agent.
If the coefficient of friction of a polymer film for receiving an image is high, multiplex transfer or jamming is liable to occur. To overcome this problem, in U.S. Pat. No. 5,310,591, there is disclosed the use of a slipping agent. However, if a material having a low surface tension is used as the slipping agent, toner adhesion properties are severely deteriorated. Also, fine cratering may be formed on the surface of a substrate, which may impair film appearance.
In addition to a toner receiving binder, an antistatic agent, a slipping agent, a catalyst and the like, which are added to a coating layer of a polymer film for electrophotographic copier, may cause a blocking phenomenon, resulting in several problems such as multiplex transfer or jam.
These problems must be overcome by polymer films for electrophotographic copiers. In U.S. Pat. No. 3,618,742, paper is added so that a polymer film is smoothly carried in a copier. Although adding the paper suppresses an increase in the charge on the surface of the polymer film, the paper increases the cost and the amount of waste.
As described above, the conventional polymer film for use in an electrophotographic copying process cannot suffice toner adhesion properties, antistatic properties, a low coefficient of friction, excellent anti-blocking properties and the like at the same time.
SUMMARY OF THE INVENTION
In view of the above, it is an objective of the present invention to provide a composition for an image receiving layer capable of forming an image receiving layer having excellent toner adhesion properties, an excellent antistatic property, a low coefficient of friction, excellent anti-blocking properties and a pleasing appearance.
It is another objective of the present invention to provide a polymer film for copying having an image receiving layer having excellent toner adhesion properties, excellent antistatic properties, a low coefficient of friction, excellent anti-blocking properties and a pleasing appearance.
Accordingly, to achieve the first objective, there is provided a composition for an image receiving layer including 2 to 20% by weight of a thermoplastic copolymer containing methylmethacrylate residue and butylacrylate residue, 0.1 to 10% by weight of a heat-curable polymer capable of forming a cross link with the thermoplastic copolymer, 0.01 to 0.5% by weight of a reactive silicon-based slipping agent having at least one functional group selected from the group consisting of a conjugate doub
Kyu-seok Kim
Tae-houng Jeong
Kiliman Leszek
Nixon & Vanderhye P.C.
Presta Frank P.
SKC Co. Ltd.
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