JPS61176937A - Insulating recording film - Google Patents

Abstract

PURPOSE:To improve mechanical strength, corona resistance, and electrostatic charge retentivity and to stabilize image characteristics at the time of repeated uses by a toner image forming layer made of a silicon compd. represented by a specified formula, a film layer, and an electrostatic latent image forming layer in succession. CONSTITUTION:The insulating recording film is composed of a laminate of the toner image forming layer, the film layer, and the electrostatic latent image forming layer. The toner image forming layer opposite to a toner developing machine is composed essentially of hydrolyzate of the silicon compd. by the formula shown on the right in which R is an org. group having a C directly combined Si, X is halogen or <=6C alkoxy, and n, m are each an integer of 0-4, and m+n=4. The electrostatic latent image opposite to a recording electrode is composed of an abrasion resistant spacer contg. a filler, and an insulating binder resin good in resistances to corona and ozone, thus permitting the film to be high in mechanical strength, and the electrostatic latent image forming layer to be improved in resistances to corona and abrasion, and charge retentivity under high humidity, and stabilized in image characteristics even at the time of repeated uses, and the toner to be improved in cleanability, filming resistance, etc.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an insulating recording film used in an electrostatic recording method that directly converts an electric signal into an electrostatic latent image. An electrostatic recording method (so-called This invention relates to an insulating recording film that is repeatedly used in "contrographies".

[Prior art]

Recently, an electrostatic recording method (so-called "powder contrast") has been developed in which a recording electrode and a toner development chamber are provided between an insulating recording film in which an electrostatic latent image forming layer is laminated on a Plus 2 film. Improvement methods have been proposed (for example, JP-A-57-105758; JP-A-57-105758;
Publication No. 195258, etc. According to these proposals, the electrostatic latent image forming surface formed by the recording electrode and the toner image forming surface formed by the toner developing device can be separated, which facilitates cleaning when repeatedly used as a master film and extends the lifespan of the recording medium. In addition, since the process can be simplified compared to the conventional electrostatic recording method, the apparatus can also be made smaller.

The insulating recording film used in the above recording method is generally thin because resolution deteriorates if it is too thick, so it is important to check film permeability during manufacturing, processability, and repeated use as a master film. Therefore, sufficient mechanical strength is required.

In addition, in order to obtain stable image characteristics as a master film, the electrostatic latent image forming layer has corona resistance, abrasion resistance,
On the other hand, the toner image forming surface has good charge retention under high humidity.
Toner cleaning properties, toner filming resistance, and toner abrasion resistance are required.

None of the conventionally known insulating recording films satisfies all of the above-mentioned required characteristics, and this has been a major obstacle to practical application.

(Problems to be Solved by the Invention) The present invention does not have the above-mentioned drawbacks, that is, (a) the film has high mechanical strength, (b) the electrostatic latent image forming layer has good corona resistance and abrasion resistance; It has good charge retention under high humidity, and (c) the surface of the plastic film that comes into contact with the toner has good toner cleaning properties, toner filming resistance,
It is an object of the present invention to provide an insulating recording film that has good abrasion resistance against toner and has stable image characteristics even after repeated use.

[Means for solving problems]

In order to achieve the above object, the present invention has the following configuration, that is, an insulating recording film used in an electrostatic recording method in which a recording electrode and a toner developing device are provided on both sides of the insulating recording film for recording. A> The insulating recording film is formed of a laminate in which a toner image forming layer, a plastic film layer and an electrostatic latent image forming layer are laminated in this order,
(B) The toner image forming layer is provided on the side facing the toner developing machine, and has the general formula RnSiXm (wherein R is an organic group in which carbon is directly bonded to silicon, and X is a halogen group or an alkoxy group). (Number of carbon atoms is 6 or less), n and m are integers from O to 4, respectively, and values that satisfy n+m=4)
(C) the electrostatic latent image forming layer is provided on the side facing the recording electrode; The present invention is also characterized by an insulating recording film formed of a layer consisting of an insulating polymer binder and a spacer means.

The toner image forming layer of the present invention has the general formula % organic group in which carbon is directly bonded to silicon, including lysidoxy, mercapto, amino, etc., X is a halogen group, an alkoxy group (methoxy, ethoxy, propoxy, butoxy, etc.). A prepolymer obtained by hydrolyzing one or more of the compounds shown in the following formula (with a carbon number of 6 or less), where n and m are each an integer from O to 4, and a value satisfying n+m=4. Curing catalysts, additives (e.g. adhesion promoters, antistatic agents, pH adjusters, wetting improvers, plasticizers, stabilizers, antioxidants, ultraviolet absorbers, lubricants, antifoaming agents, thickeners) as necessary Examples include compositions obtained by dissolving the mixture in a solvent together with other substances (such as chemistries, coloring agents, etc.) and curing the solution by heating or by radiation such as ultraviolet rays, β rays, and γ rays. Of course, those precondensed in a solution state are also included.

Among the silicon compounds represented by the general formula RnSiXm, particularly preferred are those selected from one or more compounds where m=3 and/or m=4.

Further, colloidal silica can be blended within a range that can maintain the properties of the silicon compound. Colloidal silica is effective as a colloidal solution in which silicic anhydride is dispersed in water or an alcoholic solvent, and is produced by a well-known method.
It is commercially available. For the purpose of the present invention, average particle diameters of 5 to 1 OO nm are useful.

The thickness of the toner image forming layer is not particularly limited, but is usually preferably 0.5 to 10 μm. More preferably, 0
．． A thickness of 5 to 5 μm is desirable. If it is thicker than this, the abrasion resistance will not be sufficient, and if it is thicker, the image quality will be poor and the curing time will be longer, which is undesirable.

The plastic film in the present invention is a film made of a commonly known insulating thermoplastic resin or thermosetting resin. Resins for this film include polyester, polyolefin, polyamide, polyester amide, polyether, polyimide, polyamideimide, polystyrene, polycarbonate, polyphenylene sulfide polyether ester, polyvinyl chloride, poly(
Preferred are meth)acrylic acid esters and the like.

Furthermore, copolymers, blends, and crosslinked products of these can also be used. Further, it is preferable that these resins be stretched, since mechanical strength, dimensional stability, thermal properties, optical properties, etc. are improved. Among these, polyester is preferably used. Here, the polyester is a polyester containing an aromatic dicarboxylic acid as a main acid component and an alkylene glycol as a main glycol component.

Specific examples of aromatic dicarboxylic acids include terephthalic acid,
Isophthalic acid, naphthalene dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic diphenylsulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid, α,β-bis(2-chlorophenoxy)ethane-4,4 '-dicarboxylic acids and the like. Among these, terephthalic acid is particularly desirable.

Specific examples of alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol, and the like. Among these, ethylene glycol is particularly desirable.

Of course, these polyesters may be homopolyesters or copolyesters (copolymerized polyesters), and examples of copolymerized components include diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, p- Diol components such as xylylene glycol, 1,4-cyclohexane dimetatool, 5-sodium sulforesorcin, adipic acid, sebacic acid, phthalic acid, isophthalic acid,
Dicarboxylic acid components such as 2,6-naphthalene dicarboxylic acid and 5-sodium sulfoisophthalic acid, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, p
-Oxycarphonic acid components such as oxyethoxybenzoic acid and the like can be mentioned.

In addition, the thickness of the plastic film is 5 μm to 50 μm.
It is preferable that More preferably 5 μm to 25 μm
It is desirable that it is μm. If it is thinner than this, the film will not have sufficient mechanical strength, and if it is thicker than this, the resolution will deteriorate, which is not preferable.

These plastic films may be subjected to known surface treatments, such as corona discharge treatment, plasma discharge treatment, anchor coating, etc., to improve adhesion, if necessary.゛Also, within a range that does not impair the effects of the present invention, in order to improve toner cleaning properties, toner filming resistance, etc., a release agent may be added, or a release agent may be added to the side opposite to the electrostatic latent image forming layer. A release agent may be applied to the surface or a release film may be laminated.

The electrostatic latent image forming layer consists of an insulating polymeric binder and spacer means. The insulating polymer binder is made of a thermoplastic resin or a curable resin, and the spacer means is made of a filler, which is not particularly limited as long as it is a commonly known resin or filler. As the insulating polymer binder, thermoplastic resins such as polyester, polyesteramide,
Polyvinyl acetal, polyvinyl chloride, poly(meth)
Acrylic esters, polyamides, polyurethanes, polycarbonates, polystyrene, polymethylpentene, alkyd resins, polyamideimides, silicone resins, fluororesins, copolymers and blends of these, and curing that is cured by heat, light, oxygen, etc. Examples include phenol resins, melamine resins, epoxy resins, crosslinked organosilicon compounds, and those obtained by adding a crosslinking agent to a poly(meth)acrylic acid ester copolymer containing a reactive polymer. . Among these, those obtained by adding a crosslinking agent to a poly(meth)acrylic acid ester copolymer containing a reactive monomer and crosslinking are particularly preferred.

Such reactive materials include functional groups such as carboxyl groups (for example, (meth)acrylic acid, etc.), hydroxyl groups (such as 2-hydroxyethyl (meth)acrylate), and amide groups ((meth)acrylic acid amide, etc.). nato),
Glycidyl group ((meth)acrylic acid glycidyl group, etc.)
, a compound containing an amino group (such as 2-diethylamine ethyl (meth)acrylate), and the like. The crosslinking agent for these reactive monomers is appropriately selected from, for example, amino resins, epoxy resins, melamine resins, isocyanates, and the like. Additives such as a crosslinking accelerator may be added to the coating.

Since the insulating polymer binder is exposed to corona discharge and ozone when used repeatedly, it is preferably used that has good corona resistance and ozone resistance. Among these materials, polycarbonate, polyester, polystyrene copolymers, crosslinked poly(meth)acrylate copolymers, and the like are particularly desirable.

Fillers constituting the spacer means include, for example, inorganic fillers such as silicon oxide, titanium oxide, magnesium oxide, zinc oxide, beryllium oxide, alumina, barium titanate, zirconia, and calcium carbonate, melamine resin, and styrene-divinylbenzene-based fillers. Examples include, but are not limited to, organic fillers such as copolymers, phenolic resins, epoxy resins, and polyimides. The fillers may be used alone or in combination of two or more.

Further, from the viewpoint of wear resistance during repeated use, the spacer means preferably contains at least one filler having a Mohs hardness of 7 or more. Examples of such inorganic fillers include alumina (Mohs hardness: 9)
, steatite (same 8), spinel (same 8), quartz (same 7), zirconia (same 7), etc. are preferably used.

Among these, alumina is preferably used, and it is particularly preferable that the alumina be α-type crystal, have a purity of 95% by weight or more, and have a low content of alkali metal. Further, the smaller the porosity, the better, and it is most preferable that the porosity is substantially O.

The surface roughness of this electrostatic latent image forming layer is preferably 5 μm to 30 μm. More preferably 5 μm to 20 μm
It is desirable that If it exceeds this range, the discharge stability during recording will be poor and the image characteristics will be poor, which is not preferable. For this reason, the average particle diameter of the spacer means is appropriately selected within the range of about 5 μm to 30 μm, although it depends on the amount of coating.

Here, the weight ratio of polymeric binder/spacer means is 10
It is preferable to select it appropriately within the range of 0/1 to 100/150. If it is smaller than this range, the discharge stability will be poor, while if it is larger than this range, the film strength of the electrostatic latent image forming layer will be weakened, which is not preferable.

In addition, in the spacer means, an inorganic filler with a Mohs hardness of 7 or more (referred to as filler (I)) and a Mohs hardness of 7 or more are used.
Less than 10% inorganic filler or organic filler (filler (
The weight ratio of filler (■)/filler (referred to as n) is
It is preferable that n)=10010 to 10/90 from the viewpoint of wear resistance.

In addition, the average particle size is filler (I)≧filler (I
I) is preferable from the viewpoint of wear resistance.

The electrostatic latent image forming layer may be a single layer or a plurality of layers, and an intermediate layer such as an adhesive layer may be provided between the plastic film and the electrostatic latent image forming layer.

As the method of adding the toner image forming layer and the electrostatic latent image forming layer of the present invention, commonly known methods can be effectively used.

For example, brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, rotary coating (spinner,
Whaler, etc.).

The electrostatic latent image forming layer of the present invention having a moisture absorption rate of 0.5% or less is particularly preferably used because it has good image characteristics under high humidity.

[Effects of the Invention] The present invention provides an insulating recording film in which a toner image forming layer, a plastic film layer, and an electrostatic latent image forming layer are laminated in this order. Since it is composed of a film and an electrostatic latent image forming layer, (a) the mechanical strength of the film is high;
(b) The electrostatic latent image forming layer has good corona resistance, abrasion resistance, and charge retention under high humidity, and (c) the toner image forming layer has good toner cleaning properties, toner filming resistance, and toner resistance. An insulating recording film with good abrasion resistance and stable image characteristics even after repeated use can be obtained.

Since the insulating recording film of the present invention has excellent properties as described above, it can also be used as a display film or a hard copy film that is directly fixed.

[Method of measuring characteristics, evaluation criteria]

(1) Electrostatic copying paper tester (EPA-3P) manufactured by Rodenki Seisakusho for charge retention properties
-428> was applied to the electrostatic latent image forming layer of the insulating recording film at a voltage of +5 kV for 5 seconds to determine the electrostatic charge acceptance potential (Vo), and then the potential after standing for 30 seconds ( V2O) and charge retention rate (-(V2O/Vo
) X 100 (%)).

It is preferable that it is 80% or more.

(2) Moisture absorption rate After coating the electrostatic latent image forming layer solution on a glass plate and thoroughly drying it (sufficiently cross-linking those that cause cross-linking), 20'C.6
Measure the weight after treatment in 5% RH for 24 hours.
), then treated in a hot air oven at 150'C for 15 hours, dried and weighed W2), Moisture absorption rate (%) = (Wl - W2 > /W2 x
Calculated as 100.

It is particularly preferable that the moisture absorption rate is 0.5% or less.

(3) Evaluation of image characteristics A multi-stylus recording electrode is placed on the surface of the electrostatic latent image forming layer with an insulating recording film in between, and a magnetic toner developing device is placed oppositely on the toner image forming surface. While bringing the tip of a magnetic brush with body toner into contact with the toner image forming surface of the insulating recording film, an aoov is applied between the multi-stylus recording electrode and the magnetic toner developing device to generate an electrostatic charge on the electrostatic latent image forming layer. The electrostatic charge held the powder toner of the magnetic toner developing machine on the toner image forming surface to develop an image, which was then transferred to plain paper and then fixed to obtain a copied image. The insulating recording film was neutralized, cleaned of residual toner, and used repeatedly.

Hereinafter, one embodiment of the present invention will be described based on Examples. The present invention is not limited to this.

Examples 1 to 4 A self-crosslinking acrylic emulsion was applied on one side of a 12 μm thick biaxially stretched polyethylene terephthalate film (“Lumirror” manufactured by Toshiku Co., Ltd.) to a thickness of 0.5 μm after drying.
After coating to form an adhesive layer, α
-glycidoxypropylmethyljethoxysilane at 0.
Hydrolyzate obtained by hydrolysis with 01N hydrochloric acid aqueous solution
>100 parts by weight of epoxy resin 45% containing 61% solids
Parts by weight, 150 parts by weight of colloidal silica dispersed in methanol (solid content concentration 30%), 9 parts by weight of aluminum acetylacetonate, 0.32 parts by weight of silicone surfactant, inpropyl alcohol/n-butyl alcohol as solvent. A paint containing 200 parts by weight of the -2/1 mixture was applied to form a toner image forming layer (to a thickness of 3 μm after drying).

Next, on the opposite side of the toner image forming layer, an adhesive layer of self-crosslinking type acrylic emulsion was provided so that the thickness after drying was 0.5 μm, and then an electrostatic latent image forming layer as shown in Table 1 was formed. (The weight of the electrostatic latent image forming layer after drying was 8 g/Tr12 in each case) to obtain the insulating recording film of the present invention (Examples 1 to 3).

Various properties of the obtained insulating recording film are summarized in Table 2.

Table 2 shows that the insulating recording film of the present invention has good charge retention and good image characteristics can be obtained even after repeated use. It is clear that it has good corona resistance and abrasion resistance. (The alumina used in this example had a purity of 9.
The porosity was O at 8.0% by weight or more. )

Claims (1)

[Claims] (1) In an insulating recording film used in an electrostatic recording method in which a recording electrode and a toner developing device are provided with an insulating recording film sandwiched therebetween, (A) the insulating recording film includes a toner image forming layer, a plastic It is formed of a laminate in which a film layer and an electrostatic latent image forming layer are laminated in this order, and (B) the toner image forming layer is provided on the side facing the toner developing machine and has a general formula RnSiXm (in the formula R is an organic group in which carbon is directly bonded to silicon; (C) the electrostatic latent image forming layer is provided on the side facing the recording electrode, and An insulating recording film characterized in that it is formed of a layer consisting of an insulating polymer binder and a spacer means.