JPH04145452A - Liquid developer for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a positively chargeable liq. developer for electrophotography having high coloring power, hardly causing ground stain of a non-image area and maintaining developing performance attained immediately after production over a long period of time by adding specified halogenated alkylsilane and/or a specified siloxane deriv. as a positive charge imparting agent to a developer. CONSTITUTION:Halogenated alkylsilane represented by formula I and/or a siloxane deriv. represented by formula II is incorporated into a nonpolar carrier liq. having high insulating property. In the formula I, each of R<1>-R<3> is H, optionally substd. aliphatic hydrocarbon or OR<4>, R<4> is H or optionally substd. aliphatic hydrocarbon, X is H or halogen and each of m and n is an integer of 0-8 but m and n are not simultaneously 0. In the formula II, R<5> is H, optionally substd. aliphatic hydrocarbon or OR<6>, R<6> is H or optionally substd. aliphatic hydrocarbon, Y is H, halogen or optionally substd. aliphatic hydrocarbon and n is an integer of 0-5.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a liquid developer for electrophotography, and in particular, it prevents background smearing, image blurring, etc. in a positively charged developer, and improves the performance over time. This invention relates to an electrophotographic liquid developer with improved stability.

(Prior art) Is there a dry development method or a liquid development method as a method for converting an electrostatic latent image obtained by electrophotography into a visible image? Issues such as stability over time, ease of handling, odor, etc. For this reason, the dry developing method is now commonly used.

However, recent demands for higher image quality are forcing us to reconsider the necessity of the liquid development method.

The developer used in the liquid development method is made by suspending colored fine powder (hereinafter referred to as toner) in an electrically insulating carrier liquid, and due to its small particle size, it is more difficult to use than other developers. It is possible to obtain images with good fine line reproducibility and high contrast.
This feature is also exhibited in full-color development using toners of four colors, cyan and black, and is a major reason why high resolution and high gradation image quality can be obtained.

In general, liquid developers are electrically insulating non-polar liquids.
It is often made up of suspended dye particles, such as phthalone anine blue, azo pigment, carphone blank, etc., which cannot sufficiently hold the charge of the desired sign. .

Therefore, in order to improve charge control and dispersion stability, an insulating resin that is insoluble or soluble in the insulating nonpolar liquid is used, or a resin that can be dissolved in the insulating nonpolar liquid, a charge imparting agent, etc. is contained. Kotokashi is held.

There are many known charge-imparting agents that negatively charge the developer, such as lecithin, anionic surfactants, and metal soaps. Publication No. 43-21798, Special Publication No. 13440/1973, Publication No. 746/1973
Publication No. 2, Special Publication No. 48-79640, Special Publication No. 1977
-17742, etc.

In addition, charge imparting agents for positively charging the developer are disclosed in Japanese Patent Publication No. 44-22678, Japanese Patent Publication No. 43157-1982, Japanese Patent Publication No. 26594-1972, Japanese Patent Publication No. 49-265.
Although there are publications such as No. 6596, there are not many reports.

(Invention or Problem to be Solved) As mentioned above, there are not many reports on research on charge imparting agents in electrophotographic liquid developers, especially positive charge imparting agents that positively charge the developer. Immediately after manufacturing or for a short period of time, these developers also have strong adsorption of resin, charge-imparting agent, etc. to the dye and pigment particles, and the charge on the particles is stable, so the dispersibility is good and further development is possible. However, as time passes, adsorbed substances such as resin gradually separate from the dye and pigment particles, the charge of the toner weakens, and the dispersion stability deteriorates, making it impossible to maintain the developer performance immediately after manufacture. There were many things.

Many researchers have continued research over many years to solve these problems, and although many improvements have been made, there is still a positive charge that provides stable and good charge characteristics over a long period of time. The reality is that there are very few additives.

The present inventor has found that halogenated alkylsilanes such as chloropropyltrichlorosilane and trifluoropropyltrichlorosilane are good charge-imparting agents.

However, although these materials have a great effect on developing performance, they are themselves strongly acidic and therefore difficult to handle.

Furthermore, since it is strongly acidic, it may corrode the metal of the developing device.

The purpose of the present invention is to use a positive charge-imparting agent that is neutral to acids and bases and is very easy to handle, to provide high coloring strength and less scumming in non-image areas, for a long period of time, immediately after production. An object of the present invention is to provide a positively charged electrophotographic liquid developer having developer performance.

[Structure of the invention]

(Means for Solving the Problems) The present inventor has developed a developer using a halokenated alkylsilane represented by the following general formula (I) and/or a siloxane derivative represented by the general formula (■) as a positive charge imparting agent. It was discovered that the desired performance could be obtained by adding it to the inside, leading to the present invention.

- Formula (I) (wherein l?' to R2 are each independently a hydrogen atom,
represents a substituted or unsubstituted aliphatic hydrocarbon group or OR''. Here, R4 represents a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group.

Moreover, X represents a hydrogen atom or a halogen atom.

m and n each independently represent an integer from 0 to 8, but they cannot all be O at the same time. ) - Formula (II) R' R5 (wherein, R5 represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, or OR@; here, R6 represents a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group) represents a group.

Further, Y represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted aliphatic hydrocarbon group.

n represents an integer from 0 to 5. ) R1 to R' in the above formulas (I) and (II),
The substituted or unsubstituted aliphatic hydrocarbon group of Y is
Examples include methyl group, ethyl group, propyl group, inopropyl group, butyl group, methyl sulfide group, methoxy group, ethoxy group, protoxy group, and the like.

Specific examples include trichloropropylmethoxysilane, trichloropropylmethyldimethoxysilane, trichloropropylbropylsiethoquinone, tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, and trifluorohexyltrimethoxysilane. Ran, etc. can be mentioned.

The halogenated alkylsilane represented by the general formula (1) and 2/or the general formula (■) of the present invention is
Preferably i;to, 0001-0.1% by weight, more preferably 0.001-0.01% by weight.

The insulating carrier liquid used in the present invention has a volume resistivity of 109 Ω·Cm or more and a dielectric constant of 3 or less, such as normal paraffin hydrocarbons, isoparaffin hydrocarbons, aliphatic hydrocarbons, and aromatic hydrocarbons. , halogenated aliphatic hydrocarbons, and preferably isoparaffinic hydrocarbons having an initial boiling point of +40°C to 200°C.

In addition, various dyes and pigments can be used as coloring agents suspended in the liquid developer of the present invention, such as phthalocyanine blue, azo pigment, carphone black, nigrosine, alkali blue, etc. or give particularly favorable results.

Furthermore, resins used in combination to assist in charge control and dispersion stability of the dyes and pigments include acrylic resins such as polyacrylic esters and polymethacrylic esters, polystyrene, and polyethylene-acrylic acid copolymers. , polyethylene-methacrylic acid copolymer, polyethylene-hinyl acetate copolymer, and the like can be used, but the present invention is not limited thereto.

The present invention will be explained below with reference to Examples.

(Examples) Example 1 Polyethylene-methacrylic acid copolymer 20 parts Carbon black 1 part Isopar G (trade name manufactured by Efnon Co., Ltd.) 80 parts The above mixture was placed in an attritor and kneaded for 30 hours to obtain a concentrated developer. This was diluted with Isopar G to a non-volatile content of 1.5% and used as a developer. 0 for 1500 parts of the developer
．． When chloroprobilt 11 methquinonolano was added at a ratio of 0.05 parts and an image was output using a liquid developer copying machine (Savin 870: Seihin Co., Ltd.), a reflection densitometer (7 parts) was added.
1.3 as measured with 7 Bell R1-918, 7 Kubes Co., Ltd.
A good image with good reproduction of fine lines was obtained without any background smear. Furthermore, after this developer was left at room temperature for 50 days, the image was outputted again, or an image equivalent to the initial image was reproduced.

Example 2 Polyethylene-methacrylic acid copolymer 20 parts carbon black 1 part Aituba-G
80 parts of the above mixture was placed in an attritor and kneaded for 30 hours to obtain a concentrated developer. This is diluted with Isopar G to a non-volatile content of 1.5% and used as a developer. To 1,500 parts of the developer C: 0.05 part of chloroσpropylmethylnomethoquinonolane was added and used in a liquid developing copying machine (Savin 870:t (f'n Co., Ltd.)).
When the image was output using a reflection densitometer (7 Kubes RZ)
918: Macbeth Co., Ltd.), there was no background stain of 1.3 or higher, and a good image with good reproduction of fine lines was obtained. Furthermore, after this developer was left at room temperature for 50 days, the image was outputted again, or an image equivalent to the initial image was reproduced.

Example 3 Polyethylene-methacrylic acid copolymer 20 parts Carphone blank 1 part Isopar 0
80 parts of the above product was placed in an attritor and kneaded for 30 hours to obtain a concentrated developer. This was diluted with Isopar G to a non-volatile content of 1.5% and used as a developer. 1,500 parts of the developer (trifluorobrobyltrimethoquinonolane was added at a ratio of 0.05 parts to 2 parts) and an image was output using a liquid developing copier (Savin 870, Seihino), and a reflection densitometer (Macbeth RZ) −
918: Macbeth Co., Ltd.), and there was no background stain of 1.3 or more, and a good image with good reproduction of fine lines was obtained. Furthermore, after this developer was left at room temperature for 50 days, the image was outputted again, or an image equivalent to the initial image was reproduced.

Example 4 Polyethylene-methacrylic acid copolymer 20 parts Carbon blank 1 part Isopar 0
80 parts of the above product was placed in an attritor and kneaded for 30 hours to obtain a concentrated developer. This is diluted with Isopar〇 to a non-volatile content of 1.5% and used as a developer. After adding 1500 parts of the developer (chlorobrobyl methyl noethoquinonolane at a ratio of 0.05 parts to 2 parts) and outputting an image using a liquid developing copying machine (Savin 870: Sabin Co., Ltd.), a reflection densitometer (Macbeth) was used. RZ91
8: A good image with good reproduction of fine lines was obtained, with no background stains of 1.3 or higher as measured by Macbeth Co., Ltd. Furthermore, after leaving this developer at room temperature for 50 days, did you output the image again?
An image equivalent to the initial one has been reproduced.

Example 5 Polyethylene-methacrylic acid copolymer 20 parts Carbon blank 1 part Isopar 0
80 parts of the above product was placed in an attritor and kneaded for 30 hours to obtain a concentrated developer. This is diluted with Isopar G to a non-volatile content of 1.5% and used as a developer. 1,500 parts of the developer (toritekafur and rooctyltrimethocino 7ran was added at a ratio of 0.05 parts to 2 parts) was used in a liquid developing copier (Savin 870/Seipi 71).
When the image was outputted using a reflection densitometer (7 Kubes RZ-918, manufactured by Macbeth Inc.), a good image with good reproduction of fine lines was obtained, with no background stains of 1.3 or higher.

Furthermore, after this developer was left at room temperature for 50 days, the image was outputted again, or an image equivalent to the initial image was reproduced.

Example 6 Polyethylene-vinyl acetate copolymer 20 parts Carbon black 1 part Isopar 0
80 parts of the above-mentioned product was placed in an atlater and kneaded for 30 hours to obtain a concentrated developer. This was diluted with Isopar G to a non-volatile content of 1.5% and used as a developer. 1,500 parts of the developer (trifluoro-10-pyrutrimethoquino-7 was added at a ratio of 0.05 to 2) and an image was output using a liquid developing copier (Savin 870: Sei E7 Co., Ltd.), and a reflection densitometer (7 Kubes R
Z-918 (Macbeth Co., Ltd.), there was no background stain of 1.3 or higher, and a good image with good reproduction of fine lines was obtained. Furthermore, after this developer was left at room temperature for 50 days, the image was outputted again, or an image equivalent to the initial image was reproduced.

Example 7 Polyethylene-methacrylic acid copolymer 20 parts Onol Yellow FG1310 (pigment, trade name, manufactured by Toyo Ink Mfg. Co., Ltd.) 1 part Isopar 0 80 parts The above materials were placed in an attritor and kneaded for 30 hours to obtain a concentrated developer. .

This was diluted with Isopar G to a non-volatile content of 1.5% and used as a developer. 1,500 parts of the developer (trifluoropropyl and trifluoropropyl at a ratio of 0.05 to 2) was added to a liquid developing copier (Savin 870: Sei E7).
When the image was output using a reflection densitometer (Macbeth RZ-918: Macbeth Co., Ltd.), a good image with good reproduction of fine lines was obtained, with no background stains of 1.3 or higher.

Furthermore, after leaving the second developer at room temperature for 50 days, the image was outputted again, or an image equivalent to the initial image was reproduced.

Example 8 Polyethylene-methacrylic acid copolymer 20 parts Carbon black 1 part Isopar 0
80 parts of the above product was placed in an attritor and kneaded for 30 hours to obtain a concentrated developer. This was diluted with Isopar G to a non-volatile content of 1.5% and used as a developer. 1,500 parts of the developer (hebutadecafluorotenoltrimethoquinolano was added at a ratio of 0.05 parts to 2 parts) and a liquid developer copying machine (Savin 870:t(El/
When the image was outputted using a reflection densitometer (Macbeth R2-918 Macbeth Co., Ltd.), there was no background smear of 1.3 or more, and a good image with good reproduction of fine lines was obtained. Furthermore, after this developer was left at room temperature for 50 days, the image was outputted again, or an image equivalent to the initial image was reproduced.

(Effects of the Invention) The liquid developer for electrophotography of the present invention uses a charge imparting agent that is neutral to acids and bases and is very easy to handle, and has good positive chargeability. It has extremely excellent stability.

Claims (1)

[Scope of Claims] A halogenated alkylsilane represented by the general formula (I) in a highly insulating non-polar carrier liquid having a volume resistivity of at least 10^9 Ω·cm and a dielectric constant of 3 or less, and/or Or an electrophotographic liquid developer characterized by containing a siloxane derivative represented by general formula (II). General formula (I) (wherein R^1 to R^3 are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, or OR^
Represents 4. Here, R^4 represents a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group. Moreover, X represents a hydrogen atom or a halogen atom. m and n each independently represent an integer from 0 to 8, but they cannot all be 0 at the same time. ) General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^5 represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, or OR^6. Here, R^6 is Represents a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group. Y represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted aliphatic hydrocarbon group. n represents an integer from 0 to 5.)