JPH04100063A - Liquid developer for electrophotography - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application 1. 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. Dispersed toners mainly composed of
. A recording method using such a liquid developer involves forming an electrostatic latent image on a photoreceptor, developing it with a liquid developer, transferring it to an intermediate transfer belt, and then transferring this toner image to recording paper. A transfer method (intermediate transfer method) is known (for example, U.S. Patent Publication No. 4,708,460) [Problem to be Solved by the Invention 1] When the above-mentioned prior art liquid developer is used, the above-mentioned intermediate transfer method is known. When recording with a 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 purpose of the present invention is to solve these problems and to provide a toner image with sufficient density and clear contours on recording paper with a small pressure in an intermediate transfer type recording device. The goal is to realize a liquid developer.

[Function] It is known that the aluminum alcoholate used in the present invention is effective in improving image quality such as preventing fogging in dry toners, but the inventors of the present invention have developed a method for developing liquid toners used in intermediate transfer type recording devices. The present invention has been completed by discovering that the present invention is also effective in improving image quality in the case of a photoreceptor.

[Means for Solving the Problems J] The electrophotographic liquid developer of the present invention is an electrophotographic liquid developer prepared by dispersing a toner containing a colorant and a resin as main components in a highly insulating and low dielectric constant carrier liquid. The photographic liquid developer is characterized in that the carrier liquid contains soluble aluminum alcoholate.

[Example 1 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, resin, aluminum alcoholate, and if necessary, conventional additives to a ball mill or an attritor in the presence of a small amount of a highly insulating and low dielectric constant carrier liquid. A concentrated toner may be prepared by kneading and dispersing the toner, and this may be diluted with an appropriate amount of carrier liquid. The amounts of resin and aluminum alcoholate used are 1 to 10 parts by weight and 0.0 parts by weight, respectively, per 1 part by weight of the colorant.
1 to 1 part by weight is suitable. Next, each component will be illustrated.

As a coloring agent, carbon black (MA100, #44, #33 manufactured by Mitsubishi Chemical Industries, Ltd., Uben 1250, Laven 1020, manufactured by Columbian Carbon, Black Pearl, Black Pearl 1100, manufactured by Degussa, Black Pearl, manufactured by Cabot, Printex, manufactured by Degussa), etc. 55, Special Black 4, etc.), organic pigments (insoluble azo pigments, soluble azo pigments, phthalocyanine pigments, isoindolinone-based high-grade pigments, cinchona quatone-based high-grade pigments, perinone/perylene-based high-grade pigments).

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, polystyrene polyolefin copolymer, polyvinyl chloride resin, chlorinated polypropylene,
Examples include polyamide resin, coumaron indene resin, rosin-modified resin, and alkylphenol-modified xylene resin. Highly insulating (resistance value 101°Ωcm or more) as a carrier liquid,
Low dielectric constant (dielectric constant 3 or less) solvent, n-hexane.

Aliphatic hydrocarbons such as n-hebutane, n-nonane, n-octane, 1sO-octane, 1so-dodecane, and mixtures thereof (Isopar manufactured by Exxon Chemical Co., IP solvent manufactured by Idemitsu Petrochemical Co., Ltd., etc.) are used. . Any aluminum alcoholate may be used as long as it is soluble in the carrier liquid, such as AIPD (aluminum isopropylate), AMD (mono-5ec-butoxyaluminum diisopropylate), and ASBD manufactured by Yoken Fine Chemical Co., Ltd.
(aluminum 5ec-butyrate). 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. Q P 3, -301
．． ) 0g Carbon black (Mitsubishi Chemical Industries, Ltd. MA 100) 2
g Aluminum isopropylate (AIPD manufactured by Yoken Fine Chemical Co., Ltd.) 0.6 g Carrier liquid (Isopar G manufactured by Exxon Chemical Co., Ltd.) 157.4 g The mixture was dispersed in an attritor for 8 hours, and further 300 g of Isopar G was added and dispersed for 1 hour. After preparing a concentrated solution, 200 g of the concentrated solution was diluted with 1,000 g of Isopar 0 to obtain a liquid developer for electrophotography.

Comparative Example 1 An electrophotographic liquid developer was obtained in the same manner as in Example 1 except that aluminum alcoholate was omitted.

Example 2 Zero gin-modified pentaerythritol ester maleate (
Pentaline G manufactured by Rika Vercules Co., Ltd.) 60g Carbon black (Uben 1 manufactured by Colombian Carbon Co., Ltd.)
250) 12g mono-5ec-butoxyaluminum diisopropylate (AMD, manufactured by Yoken Fine Chemicals), 25g of carrier liquid (Isopar H, manufactured by Exxon Chemical Co., Ltd.) The above mixture was used in the same manner as in Example 1 to obtain a liquid developer for electrophotography. Ta.

Comparative Example 2 An electrophotographic liquid developer was obtained in the same manner as in Example 2 except that aluminum alcoholate was omitted.

Example 3 Coumarone-indene resin (Esk0nG manufactured by Nippon Steel Chemical Co., Ltd.)
90) 100g organic pigment (phthalocyanine blue) 2g aluminum 5eC-butyrate (ASBD manufactured by Yoken Fine Chemical Co., Ltd.) 8g carrier liquid (IP solvent 1620 manufactured by Idemitsu Chemical Co., Ltd.) 0g The above mixture was prepared as an electrophotographic liquid in the same manner as in Example 1. A developer was obtained.

Comparative Example 3 An electrophotographic liquid developer was obtained in the same manner as in Example 3 except that aluminum alcoholate was omitted.

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 device 3, a developing device 4, an intermediate transfer drum 50, a pressure roller 40, a peeling claw 6, a cleaning device M7, 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 by a developing device 4 using a liquid developer. 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 conveyed from the paper feeder N20 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 device 10, where it is fixed by 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.

[Effects of the Invention] As described above, the electrophotographic liquid developer of the present invention can be used to form toner images with sufficient density and clear contours on recording paper with small pressure in intermediate transfer type recording devices. This has the effect that the following can be obtained.

[Brief explanation of the drawing]

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 Heat fixing device 21 Recording paper 50 Intermediate transfer drum Applicant Seiko Epson Co., Ltd. Representative Patent Attorney Kizobe Suzuki and 1 other person

Claims (1)

[Claims] A liquid developer for electrophotography in which a toner mainly composed of a colorant and a resin is dispersed in a highly insulating and low dielectric constant carrier liquid, in which a soluble aluminum alcoholate is contained in the carrier liquid. Characteristic liquid developer for electrophotography.