JPS60130749A - Film for electrophotography - Google Patents

Abstract

PURPOSE:To improve the adhesive strength of a toner and to prevent the blurring of letters, the sticking of dust and feed in a superimposed state by coating at least one side of a plastic film having specified sheet resistance and light transmittance with an acrylic copolymer layer of a specified thickness. CONSTITUTION:At least one side of a plastic film having <=10<15>OMEGA/square sheet resistance and >=70% light transmittance is coated with an acrylic copolymer layer of <1mum thickness. A polyester film or the like is used as the plastic film. By coating the plastic film with the acrylic copolymer layer, satisfactory antistatic performance is provided without especially adding an antistatic agent, and the sheet resistance is stabilized and maintained well without deteriorating the high transparency. When the coated film is used in dry electrophotographic copying, the adhesive strength of a toner is improved, and the blurring of letters and feed in a superimposed state are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrophotographic film that has excellent transparency, easy toner adhesion, and excellent antistatic properties.

[Prior art and its problems]

Conventional electrophotographic films generally include a polyester film alone or a polyester film coated with a resin. However, this conventional electrophotographic film has drawbacks such as poor toner adhesion and antistatic properties, which tend to cause characters to bleed, and dust to adhere to them. Further, when used in an electrophotographic copying machine, double feeding from the supply tray tends to occur, and it cannot be said that the film has sufficient characteristics required for an electrophotographic film.

[Objective of the Invention] ' The object of the present invention is to provide a toner with good adhesion and no smearing of characters, and to prevent dust from adhering to the toner and double feeding from the supply tray when used in a dry type electrophotographic copying machine. The object of the present invention is to provide an electrophotographic film that does not cause such problems.

[Structure of the invention]

The electrophotographic film of the present invention that achieves the above object has a plastic film having a surface resistivity of 10 + 5 Ω or less and a light transmittance of 70% or more, more preferably 75 inches or more. It is characterized by being formed by laminating acrylic copolymers with a thickness of less than 1μ, more preferably less than 18μ.

The plastic film used in the present invention is a film made of well-known plastics, specifically, polyester, polyimide, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polycarbonate, etc. It's a film. Among these films, polyester film is preferred in view of the balance between film properties and price.

Hereinafter, a polyester film will be explained as a representative example.

The polyester film is preferably a film made of a polyester selected from the group consisting of polyethylene terephthalate, copolyester having ethylene terephthalate units as a main repeating unit, and polymer blends containing such polyester as a main component. As the copolymer polyester, the terephthalic acid component accounts for 80 moles of the acid component of the polyester,
Preferably, the ethylene glycol component accounts for 80 moles of the glycol component. The polymer blend preferably contains 70% by weight or more of the polyester and less than 30% by weight of other polymers.

The polyester used in the present invention may optionally contain a stabilizer,
Antioxidants, lubricants, ultraviolet absorbers.

It may also contain other additives.

Although the thickness of the polyester film is not particularly specified, it is preferably usually 25 to 500 microns, more preferably 50 to 200 microns from the viewpoint of handling and transportability.

Various known methods can be applied to obtain a polyester film having a surface resistivity of 10IIIQ/U3 or less. For example, a method of applying an antistatic agent to a polyester film, a method of forming a thin layer of metal or (and) a metal compound on the surface of a polyester film, a method of adding an antistatic agent during polymerization of polyester raw materials, a method of forming a film. Sometimes, methods such as mixing polyester raw materials and antistatic agents are used as appropriate. Among these methods, a method that can be performed all at once in the film forming process is most preferred, and a polyester obtained by polycondensing sodium alkylbenzene sulfonate and polyalkylene glycol as raw materials is preferred.

To reduce the surface resistivity value of the polyester film obtained by the above method to 1915Q or less,
This is important in the electrophotographic film of the present invention. If the surface resistivity value of the polyester film exceeds 1015Ω9, when used in a dry type electrophotographic copying machine, double feeding from the supply tray will easily occur and dust will adhere, making it unsuitable as an electrophotographic film. Become something.

A preferable range of such surface resistivity is 108 to 1014 st.

Further, the light transmittance of the polyester film needs to be 70 inches or more, preferably 75 inches or more. When it is less than 70%, the transparency deteriorates, making it unsuitable for forming transparent images or for second original images.

In the electrophotographic film of the present invention, the acrylic copolymer to be laminated on the polyester film includes 3
CH2=CC0OR+ from 0 to 95 molt, and C from 5 to 70 molt.
H2■ = C-COOR2, (where R is hydrogen or a methyl group.

R1 and R2 are alkyl groups having 1 to 4 carbon atoms, and R1≦R
2), each consisting of 80 to 99.9 moles of one or more acrylic monomers, and CO as an atomic group.
OH, C0NR4R5, NR4R5.

is a group selected from hydrogen or an aliphatic hydrocarbon group having 1 to 4 carbon atoms), or a group directly conjugated with these groups, or a group conjugated with these groups via an aliphatic hydrocarbon. Preferably, the monomer contains 0.1 to 20 mol of an ethylenically unsaturated monomer directly connected to double bonds between the monomers.

Explosion proof.

From the viewpoint of safety and application to the film forming process, it is preferable to use it as an aqueous dispersion.

The alkyl acrylate component represented by the above general formula determines the film-forming properties, mechanical properties, and adhesion of the copolymer, and the ethylenically unsaturated monomer can further impart stable adhesion to the copolymer. .

In producing the electrophotographic film of the present invention, the polyester film forming step and the acrylic copolymer coating step are generally performed separately. The most preferred manufacturing method is to apply an acrylic copolymer to at least one side of a polyester film that has been uniaxially stretched by a known method, dry it, and then stretch it in the right angle direction. Of course, a method in which an unstretched film is coated and then simultaneously biaxially stretched is also possible.

The thickness of the coating film (thickness of the coating film in an electrophotographic film) is less than 1 μm, preferably 0.8 μm or less and 5 μm or more.

If it exceeds 1μ, the increase in adhesion will decrease, but the transparency will decrease, and problems such as deterioration of flatness due to heat, occurrence of curls, deterioration of lubrication, and occurrence of blocking will occur.For electrophotography. It becomes unsuitable as a film.

Although it is of course possible to add an antistatic agent to the acrylic copolymer resin to be applied, the major feature of the present invention is that the antistatic properties of the polyester film as the base material extend to the surface. It is about bringing. Therefore, the desired purpose can be fully achieved without adding an antistatic agent to the acrylic copolymer coating itself, and compared to conventional electrophotographic films that only have antistatic properties added to the coating. , the surface resistivity value is stable and has excellent durability.

Also from the viewpoint of antistatic properties, it is preferable that the coating film is not thicker than necessary.

Further, the heat shrinkage rate of the electrophotographic film obtained by the present invention is preferably 1.0% or less at 150°C in order to suppress thermal deformation.

Note that the method for measuring characteristic values used in the examples described above and later in this specification is as follows.

Surface resistivity value: test piece at temperature 21°C2 humidity 65%
Humidify at RH for about 1 day, then use an insulation meter (Kawaguchi Electric Membrane, R-
503 type) under the same conditions.

Light transmittance: According to JIS K-6714.

Heat shrinkage rate: According to JIS C-2318.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on Examples.

Example 1. Comparative Examples 1-2 After adding all the transesterification catalyst to 100% by weight of dimethyl terephthalate and 65% by weight of ethylene glycol,
1% by weight of sodium dodecylbenzenesulfonate and 1% by weight of polyethylene glycol having a molecular weight of 4,000 were added, polycondensation was performed, and the obtained polyethylene terephthalate was melt-extruded to obtain an unstretched film.

This film is stretched in the longitudinal direction, and then methyl methacrylate and ethyl acrylate with a solid resin concentration of 40 inches are coated on both sides of the film.

Acrylic acid copolymer (copolymer composition, 85:12:
3 mol%) 7.5% by weight of aqueous dispersion, 0.2% by weight of calcium carbonate as a lubricant, and 92.3% by weight of water as a diluent, dried, stretched in the right angle direction, and then After heat treatment, an electrophotographic film with a film thickness of 100μ, a coating thickness of 0.4μ, a surface resistivity of 3×10”Ω, a light transmittance of 83%, and a heat shrinkage rate of 0.7% was obtained. Ta.

The electrophotographic film thus obtained is compared with a polyester film alone (Comparative Example 1) and a polyester film coated with an ester resin and an antistatic agent (Comparative Example 2). That's right.

A Canon PC-10 (manufactured by Canon Sales Co., Ltd.) was used as a dry type electrophotographic copying machine.

Rice 1 Good adhesion 5. Divided into 5 levels (5) 4) 3〉2〉1 with bad as 1. If there is no bleed in the 2nd character, mark it as ○, and if it bleeds, mark it as X.○
Displayed in three stages: 〉△〉X 3 When using a copying machine with several dozen sheets stacked at once, two or more sheets will be fed stacked from the paper feed tray [Effect of the invention] As mentioned above, books The electrophotographic film of the invention has a surface resistivity of 1Q13Q/D or less and a light transmittance of 7.
Since the structure is such that an acrylic copolymer having a thickness of less than 1 μm is laminated on at least one side of a plastic film having a thickness of 0 mm or more, the following excellent effects can be obtained.

(b) When copied using a dry electrophotographic copying machine, the adhesion of the toner is good and no smudging occurs.

(b) Since it has excellent anti-static properties, there is no phenomenon of dust adhesion due to static electricity.

(c) When used in a dry type electrophotographic copying machine, no double feeding phenomenon occurs from the supply tray.

) It has good transparency and is suitable for forming translucent images and reproducing.

(e) Since the base film has antistatic properties, the surface resistivity value of the product is stable and it has excellent durability.

Agent: Patent Attorney Nobuo Kogawa - Patent attorney Kenteru Noguchi Patent attorney Kazuhiko Saishita

Claims (1)

[Claims] An electrophotographic film comprising an acrylic copolymer having a thickness of less than 1 μm laminated on at least one side of a plastic film having a surface resistivity of 10 15 Ω or less and a light transmittance of 70% or more.