JPH02199462A - Powder ink - Google Patents

Abstract

PURPOSE:To lower the fixing temp. by an electrophotographic system by internally adding specific org. matter to powder ink. CONSTITUTION:The org. matter (B) which varies in solubility parameter by >=1 from a binder resin (A) is internally added to the powder ink contg. a conductive material, such as carbon black and the resin A. The viscosity of the component B at 180 deg.C is preferably <=1X10<4>cp and the softening points of the components A, B are preferably 70 to 180 deg.C. A combination of a styrene oligomer and epoxy resin and a combination of a styrene/acrylic resin and paraffin wax, etc., are usable as the above-mentioned components.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to powder inks used in image forming apparatuses.
In particular, it relates to conductive powder ink.

[Prior Art] As a conductive powder ink, there is 5'8-10743, and in order to improve the fixing properties, the softening point of the binder resin is specified, and the flow when the powder ink is melted is controlled. properties and lowers the fixing temperature.

[Problems to be Solved by the Invention] However, in the powder ink proposed here, since the amount of conductive material is specified to ensure conductivity, the amount of melting time that can be reduced by the resin alone while preventing blocking is has limited liquidity.

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and an object of the present invention is to provide a powder ink that has improved fixability while ensuring the necessary conductivity.

[Means for Solving the Problems] The powder ink of the present invention is composed of a conductive material and a binder resin, and contains an organic substance whose solubility parameter differs from the binder resin by one or more. Additionally, the present invention is further characterized in that the conductive material is mainly dispersed in the binder resin.

[Function] According to the above structure of the present invention, since the conductive material is hardly dispersed in the added organic matter, the distance between the conductive materials is increased by increasing the ratio of the amount of the conductive material to the binder resin due to the internal addition of the organic matter. It is thought that the conductivity of the powder ink is ensured by narrowing the area. Further, it is thought that the viscosity during melting is reduced because the viscosity of the organic substance is lower than the viscosity of the excluded conductive material dispersion system.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

As the binder resin used in the powder ink of the present invention, known polystyrene and copolymers thereof, such as hydrogenated styrene resin, styrene-isobutylene copolymer, styrene-butadiene copolymer, ABS resin, and ASA resin. , As resin, AASAs resin C8 resin, ABS resin, styrene/P-chlorostyrene copolymer, -styrene/
Propylene copolymer, styrene/butadiene crosslinked polymer Styrene/butadiene/chlorinated paraffin copolymer, styrene/allyl/alcohol copolymer, styrene/butadiene/chlorinated paraffin copolymer, styrene/butadiene/chlorinated paraffin copolymer,
Butadiene rubber emulsion, styrene, maleic ester copolymer, styrene/isobutylene copolymer, styrene/maleic anhydride copolymer, acrylate resin or methacrylate resin and its copolymer, styrene/acrylic resin, The copolymer, for example,
Styrene/acrylic copolymer, styrene/diethylamino/ethyl methacrylate copolymer, styrene/butadiene/acrylic ester copolymer, styrene/methyl methacrylate copolymer, styrene/n/butyl methacrylate copolymer, styrene・Diethylamino・
Ethyl methacrylate copolymer, styrene/methyl methacrylate n-butyl acrylate copolymer, styrene/methyl methacrylate/butyl arylate/N
-(Ethoxymethyl)acrylamide copolymer, styrene/glycidyl methacrylate copolymer, styrene/
Butadiene/dimethyl/aminoethyl methacrylate copolymer, styrene/acrylic acid ester/maleic ester copolymer, styrene/methyl methacrylate/
2-ethylhexyl acrylate copolymer, styrene/n
-Butyl arylate/ethyl glycol methacrylate copolymer, styrene °n-butyl methacrylate/
Acrylic acid copolymer, styrene/n-butyl methacrylate/maleic anhydride copolymer, styrene/butyl acrylate/isobutyl maleic acid half ester/divinylbenzene copolymer, polyester and its copolymer, polyethylene and its copolymer Coalescence, epoxy resin, silicone resin, polypropylene and its copolymers, waxes, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, fluororesin, polyamide resin, polyvinyl alcohol resin, polyurethane resin, polycarbonate resin , cellulose resin, polyarylate resin, butyral resin, and polyvinyl butyral may be used alone or in combination. Furthermore, wax-like compounds can be added to the binder resin, including plant-based natural waxes such as candelilla wax, carnauba wax, and rice wax, animal-based natural waxes such as beeswax and lanolin, and mineral-based waxes such as montan wax and osikerite. Natural wax, paraffin wax, microcrystalline wax, natural petroleum wax such as petrolatum, polyethylene wax,
Synthetic hydrocarbon waxes such as Fischer-Tropsch wax, modified waxes such as montan wax derivatives and paraffin wax derivatives, hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil derivatives, and synthetic waxes such as fatty acids, acid amides, esters, and ketones. One type of selected wax or a blend of two or more types can be used.

Furthermore, carbon black, various metals, metal oxides, metal salts, etc., which are known as conductive materials for the powder ink of the present invention, may be used alone or in combination.

The organic substances used in the powder ink of the present invention include the aforementioned resins and waxes. At that time, since it is not compatible with the binder resin and does not disperse the conductive material, the solubility parameter, which is the square root of the evaporation energy per mole of the substance divided by the molar volume, is determined by the binder resin and the conductive material. If they are separated by 1 or more, they will be difficult to dissolve.

In addition to the above-mentioned substances, additives can be added to the powder ink of the present invention to the extent that their fluidity, fixability, etc. are not impaired. Additives include metal soaps, dispersants such as polyethylene glycol, Fe5O4, Fe20a, Fe, Cr,
Magnetic powders such as Ni, Co, and ferrite are used alone or in combination.

[Example 1 solubility parameter is 11.0 [cal/cm2] 1
90 parts by weight of 0.2 μm fine particles of /2 epoxy resin,
Solubility parameter is 8.5 [cal/Cm3]""
90 parts by weight of styrene oligomer and 4 parts by weight of conductive carbon black were placed in toluene, mixed with a Henschel mixer, and then formed into particles by a spray drying method and classified to produce powder ink A1 having an average particle size of 10.2 μm. The softening point of styrene oligomer is 85°C, the softening point of epoxy resin is 95°C, and the bulk resistance of powder ink is 10°C.
2ΩCm, the viscosity at 180℃ measured with a rotational viscometer is 3
It was ×102.

An image was formed using the produced powder ink A1 using an electrophotographic image forming apparatus. At this time, A1 is
It is fixed at a fixing temperature of 90°C, and the optical temperature (hereinafter referred to as 0.D,
It is called a value. ) 1.6 images were obtained.

[Comparative Example 1] In order to obtain the same volume resistivity as in Example 1, 1.8 parts by weight of conductive carbon black was added to 90 parts by weight of styrene oligomer in toluene, and then subjected to a Henschel mixer. Particles were formed using a spray dryer and classified to produce powder ink B1 having an average particle size of 10.2 μm. The volume resistivity is 102 Ωcm, and the viscosity at 180°C measured with a rotational viscometer is 1. 6 x 103c,
It was p.

When an image was formed using the prepared powder ink B1, it was fixed at a fixing temperature of 115°C, and it had a value of 0, D, and 1.
．． 6 images were obtained.

As described above, it has been found that when a conductive agent is added in an amount necessary to obtain the same resistance value, the temperature required for fixing increases compared to when no internally added resin is added.

[Example 2] 4. Conductive carbon black was added to styrene oligomer.
8 wt% was added, put in a Henschel mixer, kneaded in a three-roll mill, cooled, crushed, and classified to have an average particle size of 1.1.
A micron-sized powder was produced.

80 parts by weight of this fine powder and an epoxy resin were further mixed, mixed, and pulverized to produce a powder ink C1 having an average particle size of 10.9 μm. The volume resistivity at this time was 102 ΩCm. 1
The viscosity at 80°C was 8 x 103.

When image formation was performed using powder ink C1, 11
The image was fixed at a fixing temperature of 5° C., and an image of ◯, D, and a value of 1°6 was obtained.

[Comparative Example 2] 4.0% conductive carbon black was added to styrene oligomer.
2 wt% was added, put in a Henschel mixer, kneaded in a three-roll mill, cooled, crushed, and classified to have an average particle size of 10.
A 9 μm powder ink D1 was produced. The volume resistivity at this time was 102 ΩCm. The viscosity at 180°C is I x 1
It was 0'. When an image was formed using the powder ink D1, it was fixed at a fixing temperature of 1300C, and the image was formed at a temperature of 0. D.
An image with a value of 1.6 was obtained.

As described above, it has been found that when a conductive agent is added in an amount necessary to obtain the same resistance value, the temperature required for fixing increases compared to when no internally added resin is added.

[Example 3] Styrene with a solubility parameter of 9.5 [cal/Cm3]5'', 70 parts by weight of an acrylic copolymer, 5 parts by weight of conductive carbon black, and a solubility parameter of 12
．． 7 [cal/cm" average particle size of 1'2 0.1 μm
After mixing 10 parts by weight of paraffin wax in toluene, a powder ink having an average particle size of 1015 μm was prepared by mixing and crushing. The softening point of the styrene-acrylic copolymer was 105°C, the softening point of the paraffin wax was 90°C, the volume resistivity was 102 Ωcm, and the viscosity at 180°C was 9×103 c,p. When the powder ink is used to form an image, 0, D at a fixing temperature of 100°C.
, an image with a value of 1.6 was formed.

[Comparative Example 3] Solubility parameter is 9.5 [cal/cm3] 1'2
of styrene, 70 parts by weight of acrylic copolymer, 5 parts by weight of conductive carbon black, and a solubility parameter of 1
0. A powder ink having an average particle size of 10.5 μm was prepared by mixing 10 parts by weight of paraffin wax of 5 cal/cm3 to 1'2 in toluene, and then kneading and pulverizing the mixture.

The softening point of styrene-acrylic copolymer is 105°C, the softening point of paraffin wax is 90°C, the volume resistivity is 102Ωcm, and the viscosity at 180°C is 2X
10'c.

It was p. When an image was formed using the powder ink, an image with O, D, and values of 1 and 6 was formed at a fixing temperature of 160°C. Compared to Example 3, the fixing temperature was higher at the same resistance value, and because the solubility parameters were similar, it was confirmed by an optical microscope that the resins were compatible with each other.

Although the present invention has been described above with reference to several examples, it is clear from the above examples that the present invention can be applied to other combinations of resins that are not compatible with each other.

[Advantages of the Invention] As described above, according to the present invention, a powder ink composed of a conductive material and a binder resin contains an organic substance whose solubility parameter differs from that of the binder resin by one or more. Furthermore, since the conductive material is mainly dispersed in the binder resin, it is possible to fix at a lower temperature when a predetermined resistance value is obtained, and when used in an image forming apparatus, the running cost thereof can be reduced. In particular, if it is used as a powder ink for an image forming method that includes a step of forming an image using a thermal transfer method and a step of recycling an ink sheet, it is possible to provide an image forming apparatus with significantly reduced running costs. It becomes like this. Ma-1 Furthermore, the effect of reducing the fixing temperature was observed even when used in other image forming apparatuses. For example, it can be applied as a powder ink for use in devices such as printers, copiers, and facsimile machines that use electrophotography.

that's all Applicant: Seiko Epson Corporation

Claims (4)

[Claims] (1) In a powder ink composed of a conductive material and a binder resin, an organic substance is internally added which has a solubility parameter different from that of the binder resin by one or more, and the conductive material is mainly dispersed in the binder resin. Powder ink characterized by: (2) The powder ink according to claim 1 has a volume resistivity of 10
Powder ink characterized by ^8Ωcm. (3) The organic substance according to claim 1 has a viscosity of 1×10^4 c. at 180°C. p. A powder ink characterized by: (4) A powder ink, characterized in that the binder resin according to claim 1 and the organic substance added therein have a softening point of 70 to 180°C.