JPH04100060A - Liquid developer for electrophotography - Google Patents

Abstract

PURPOSE:To form a toner image having sufficiently high density and clear outlines under low pressure by adding a fluorine-contg. surfactant soluble in a carrier liq. to a liq. developer. CONSTITUTION:A toner based on a colorant and resin is dispersed in a carrier liq. having high insulating property and a low dielectric constant, and a fluorine- contg. surfactant soluble in the carrier liq. is further added to obtain a liq. developer for electrophotography. A desired commercially available surfactant may be used as the fluorine-contg. surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a developer used in wet recording devices such as electrophotographic copying machines and printers.

[Prior Art] As a liquid developer for electrophotography, a coloring agent consisting of a thermoplastic resin such as styrene resin or acrylic resin, or a pigment or dye such as carbon black is added to a carrier liquid consisting of a petroleum-based aliphatic hydrocarbon solvent. A toner in which a toner containing as a main component is dispersed is known (for example, JP-A-55-35321).

A recording method using such a liquid developer involves forming an electrostatic latent image on a photoreceptor and developing it with a liquid developer.
A method (intermediate transfer method) of transferring the toner image onto an intermediate transfer belt and further transferring the toner image onto recording paper is known (for example, U.S. Pat. No. 4,708,460) [Problem to be Solved by the Invention 1] When using the liquid developer of the above-mentioned conventional technology, when recording is performed with the above-mentioned intermediate transfer type recording device, the transfer efficiency is poor;
There were problems in that an image with sufficient density could not be obtained on the recording paper, and an image with clear outline could not be obtained. In the intermediate transfer method, the transfer from the intermediate transfer belt to the recording paper is performed by applying pressure between the two. However, it is necessary to increase this pressure in order to provide sufficient adhesion between the toner image and the recording paper. In actual devices, there is a limit to the pressure that can be applied, and sufficient adhesion cannot be obtained, resulting in low transfer efficiency.

The object of the present invention is to solve these problems and provide a liquid developer for electrophotography that can produce toner images of sufficient density and clear contours on recording paper with small pressure in an intermediate transfer type recording device. The aim is to realize the agent.

[Means for Solving the Problems] The liquid developer for electrophotography of the present invention is a liquid developer for electrophotography, which is made by dispersing a toner containing a colorant and a resin as main components in a highly insulating and low dielectric constant carrier liquid. The liquid developer is characterized in that the carrier liquid contains a soluble fluorine-based surfactant.

[Example] Examples of the present invention will be described.

The method for producing the liquid developer for electrophotography of the present invention includes adding a colorant, a resin, a fluorosurfactant, and, if necessary, ordinary additives to a ball mill in the presence of a small amount of a highly insulating and low dielectric constant carrier liquid. The toner may be crossed and dispersed using a means such as an attritor to form a concentrated toner, and this may be diluted with an appropriate amount of carrier liquid.

The appropriate amounts of the resin and fluorosurfactant to be used are 1 to 10 parts by weight and 0.01 to 1 part by weight, respectively, per 1 part by weight of the colorant. Next, each component will be illustrated. As a coloring agent, carbon black (Mitsubishi Chemical Industries, Ltd. MA100, #
44, #33, Uben 125 manufactured by Columbian Carbon Co., Ltd.
0, Laben 1020, Cabot Black Pearl L
, Black Pearl 1100, Degussa Printex 55, Special Black 4, etc.), organic pigments (insoluble azo pigments, soluble azo pigments, phthalocyanine pigments, isoindowanone-based high-grade pigments, quinacridone-based high-grade pigments, perinone/perylene-based high-grade pigments) pigment). In addition, oil-based dyes can be used as complementary colors if necessary.

Examples of resins include ethyl cellulose, linseed oil-modified alkyd resin, acrylic acid or methacrylic acid ester resin, polystyrene, BoT nostyrene polyolefin copolymer, polyvinyl chloride resin, chlorinated polypropylene,
Examples include boaamide resin, coumaron indene resin, rosin-modified resin, and alkylphenol-modified xylene resin. Highly insulating (resistance value of 101 Ωcm or more) as a carrier liquid,
Low dielectric constant (dielectric constant 3 or less) solvent, n-hexane,
n-heptane, n-nonane, n-octane, 1s〇-
Aliphatic hydrocarbons such as octane, 1so-dodecane, and mixtures thereof (e.g., Exxon Chemical Co., Ltd., Aitsuba Idemitsu Petrochemical Co., Ltd., PT Solvent, etc.) are used. Any fluorine-based surfactant may be used as long as it is soluble in the carrier liquid, such as Surflon S-381, S-382, 5C- manufactured by Asahi Glass Co., Ltd.
101,5C-103,5C-105, SR-100,
There are PFA-4, PFA-5, PFA-6, etc. manufactured by Neos. In addition, additives such as charge control agents can also be used as necessary. Next, specific examples of electrophotographic liquid developers made from the above components will be shown.

Example 1 Polystyrene (manufactured by Denki Kagaku Kogyo Co., Ltd. QP3-301) 0 g Carbon black (manufactured by Mitsubishi Chemical Industries, Ltd. MA 100) 2
g Fluorine surfactant (Surflon S-381 manufactured by Asahi Glass Co., Ltd.
) 0.6g carrier liquid (Isopar G manufactured by Exxon Chemical Co., Ltd.) 157.4 g The above mixture was dispersed in an attritor for 8 hours, and 300 g of Isopar G was added and dispersed for 1 hour to make a concentrated solution, and then 200 g of the mixture was dispersed in an attritor. A liquid developer for electrophotography was obtained by diluting the solution to 0.01000 g.

Comparative Example 1 An electrophotographic liquid developer was obtained in the same manner as in Example 1 except that the fluorine-based surfactant was removed.

Example 2 Zero gin-modified maleic acid pentaerythritol ester (
Pentaline G manufactured by Rika Bercules) 0g Carbon black (Uben 1 manufactured by Colopyan Carbon)
250) 12'g fluorine-based surfactant (Surflon 5C-105 manufactured by Asahi Glass Co., Ltd.)
3g carrier liquid (Isopar H manufactured by Exxon Chemical Co., Ltd.
) 25g A liquid developer for electrophotography was obtained from the mixture in the same manner as in Example 1.

Comparative Example 2 An electrophotographic liquid developer was obtained in the same manner as in Example 2 except that the fluorine-based surfactant was removed.

Example 3 Coumarone-indene resin (NISCRON G manufactured by Nippon Steel Chemical Co., Ltd.)
90) 100g organic pigment (phthalocyanine blue) 2g fluorine surfactant (PFA-6 manufactured by Neos) 8g carrier liquid (IP Solvent 1620 manufactured by Idemitsu Chemical Co., Ltd.) 0g The above mixture was used for electrophotography in the same manner as in Example 1. A liquid developer was obtained.

Comparative Example 3 An electrophotographic liquid developer was obtained in the same manner as in Example 3 except that the fluorine-based surfactant was removed.

The electrophotographic liquid developers of Examples 1 to 3 and Comparative Examples 1 to 3 were recorded on various recording papers in the following manner.

FIG. 1 is a sectional view of an intermediate transfer type recording apparatus using the electrophotographic liquid developer of the present invention. Photosensitive drum 1
A charging device 2, an exposure bag N3, a developing device 4, an intermediate transfer drum 50, a pressure roller 40, a peeling claw 6, a cleaning device 7, and a divisor device 8 are arranged in this order around the . The pressure roller 50 is composed of a metal hollow drum 51 and an elastic layer 52 covering the drum. The elastic layer 52 is preferably capable of absorbing the carrier liquid, and such an elastic layer can be obtained by using silicone rubber.

The transfer roller 50 is provided with a cleaning device 57 that removes toner remaining after transfer.

The recording operation is performed as follows. An electrostatic latent image is formed on the photoreceptor drum 1 through a charging process and an exposure process. The electrostatic latent image is developed using a liquid developer in a developing bag W4. Development is performed by selectively adhering charged toner to the electrostatic latent image by electrophoresis, and a toner image is formed on the photoreceptor 1.

Next, the intermediate transfer roller 50 and the photosensitive drum 1 are brought into contact with each other and an electric field is applied to transfer the toner image onto the intermediate transfer drum 50. On the other hand, the recording paper 21, which is a recording medium, is carried out from the paper feeding device 20 and is conveyed to a position where it contacts the intermediate transfer roller 50. Pressure is applied by a pressure roller 40. Here, the toner image on the photosensitive drum 1 adheres to the recording paper 21 and is transferred. The recording paper 21 on which the toner image has been transferred is further conveyed to the transfer bag N10, fixed with heat and pressure, and then transferred to the paper output tray 2.
It is stored in 1-1.

When bit image recording and character recording were performed on general high-quality paper, bond paper, and PPC paper using the above recording method, it was confirmed that even better recording was possible than in the comparative example regardless of the type of recording paper.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of a recording apparatus used for recording with the electrophotographic liquid developer of the present invention. 1 Photoreceptor drum 10 Thermal fixing device 21 Recording paper 50 Intermediate transfer drum Applicant Seiko Epson Co., Ltd. Representative Patent Attorney Kizobe Suzuki and 1 other person [Effects of the Invention] The liquid developer for electrophotography of the present invention is as described above. As described above, the intermediate transfer type recording apparatus has the effect that a toner image with sufficient density and clear outline can be obtained on recording paper with a small pressure.

Claims (1)

[Claims] A liquid developer for electrophotography in which a toner containing a colorant and a resin as main components is dispersed in a highly insulating and low dielectric constant carrier liquid, wherein the carrier liquid contains a soluble fluorine-based surfactant. A liquid developer for electrophotography characterized by the following.