JPH01147478A - Electrophotographic development method - Google Patents

Abstract

PURPOSE:To prevent the reduction of the extent of triboelectric charge of a toner at high humidity by using polyester resin as the principal component of the toner and coating a triboelectric charge causing member with silicone resin contg. an aminosilane coupling agent. CONSTITUTION:A toner contg. polyester resin as the principal component and a triboelectric charge causing member coated with silicone resin contg. an aminosilane coupling agent are used. The triboelectric charge causing member is the core material of a carrier which causes triboelectric charge to the toner or a transfer regulating member such as a sleeve or a doctor blade. The polyester resin content in the toner is regulated to >=40wt.%. The extent of triboelectric charge of the toner is hardly reduced in an atmosphere at high humidity.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a triboelectric charge imparting member having a function of imparting triboelectric charge to toner for developing electrostatic images used in electrophotography, electrostatic printing, etc. For example, the present invention relates to an electrophotographic development method using a carrier that imparts triboelectric charge to toner, a conveyance regulating member such as a sleeve or a doctor blade, or other triboelectric charge imparting member.

[Prior art]

In general, polyesters have various useful properties that make them useful resins for toners. for example.

When polyester is used as a resin for toner.

This is very advantageous because a sufficient negative charge can be obtained without using a charge control agent. This is thought to be because the acid, which is a raw material for polyester resin, tends to be negatively charged and the amount of charge can be adjusted by adjusting the acid value.

In addition, since polyester can be easily obtained with a relatively low melt viscosity and ester groups, carboxyl groups, and hydroxyl groups form hydrogen bonds with the cellulose of the transfer paper, good fixing properties can be obtained.

However, since the main polar group is ester, it easily absorbs moisture, and no matter what kind of triboelectric charging member is used, there is a drawback that the amount of charge decreases in a high humidity atmosphere.

〔the purpose〕

The present invention solves the drawbacks of conventional polyester toner resins, such as toner resistance in high humidity environments. The purpose of the present invention is to provide an electrophotographic developing method that prevents a decrease in iF charge and improves the durability of the developer.

〔composition〕

As a result of intensive research to achieve the above object, the inventors of the present invention have found that a toner containing a polyester resin as a main component and coated with a silicone resin containing an aminosilane coupling agent is used. It has been found that the above object can be achieved by providing a developing method characterized by using an f-electrification member.

According to the developing method of the present invention, the band 'C
rt hardly decreases.

The triboelectric charge imparting member is a carrier core material that imparts triboelectric charge to the toner, a conveyance regulating member such as a sleeve or a doctor blade, or another triboelectric charge imparting member.

Furthermore, if the content of polyester in the toner is less than 40% by weight, sufficient toner charging cannot be obtained even if the above-mentioned frictional charging member is used. Therefore, the content of polyester needs to be 40% or more.

The polyester resin used as a binder in the present invention is obtained by polycondensation of alcohol and carboxylic acid, and the alcohols used include ethylene glycol, diethylene glycol, triethylene glycol,
, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butynediol and other diols, 1,
Etherified bisphenols such as 4-bis(hydroxymethyl)cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropylenated bisphenol A, and saturated or unsaturated bisphenols having 3 to 22 carbon atoms. Examples include divalent alcohol monomers substituted with hydrocarbon groups and other divalent alcohol monomers.

Examples of carboxylic acids used to obtain the polyester resin include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and cyclohexanedicarboxylic acid.

Succinic acid, adipic acid, sepatic acid, malonic acid.

Divalent organic acid monomers substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, anhydrides of these acids, lower alkyl esters, ruic acid dimers, and other divalent organic acid monomers. Organic acid monomers can be mentioned.

In order to obtain a polyester resin used as a binder resin, it is preferable to use not only a polymer containing only the above-mentioned difunctional monomer, but also a polymer containing a component containing a trifunctional or higher polyfunctional monomer. It is. The polyhydric alcohol monomer having a valence of 3 or more is such a polyfunctional monomer.

For example, sorbitol, 1,2,3.6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
Sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, 1-limethylolpropane , 1,3.5-triμ-droxymethylbenzene, and others.

Examples of trivalent or higher polycarboxylic acid monomers include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1°2,4-cyclohexanetricarboxylic acid, 2°5. 7-Naphthalene tricarbon a
, 1,2゜4-naphthalene tricarbon M, 1,2.4
-butanetricarboxylic acid, 1,2.5-hexanetricarboxylic acid 1.1.3-dicarboxyl-2-methyl-2-
Examples include methylenecarboxypropane, tetra(methylenecarboxyl)methane, 1°2.7.8-octanetetracarboxylic acid, embol trimer acid, acid anhydrides thereof, and others.

Next, synthesis examples of several polyester resins used as toner resins in the developing method of the present invention are shown below. These syntheses can be performed by known means.

Synthesis Example 1 Terephthalic acid 7 mol (1
162g) trimellitic acid
2 moles (420 g) glycerin
0.16 mol (14,7 g) of these mixtures in 21
The mixture was heated and stirred at 0°C for about 6 hours, and after the reaction was completed, it was cooled to room temperature.
A polyester resin (A) was obtained.

Synthesis Example 2 Terephthalic acid 9 moles A mixture thereof was heated and stirred at 220° C. for about 6 hours, and after the reaction was completed, it was cooled to room temperature to obtain a polyester resin (B).

Synthesis Example 3 Isophthalic acid 9 moles A mixture thereof was heated and stirred at 200° C. for about 7 hours, and after one reaction was completed, it was cooled to room temperature to obtain a polyester resin (C).

Synthesis Example 4 Terephthalic acid 7 moles Trimellitic acid 2 moles A mixture thereof was heated and stirred at 210° C. for about 7 hours, and after the reaction was completed, it was cooled to room temperature to obtain a polyester resin (D).

Further, the toner may contain less than 60% by weight of thermoplastic resin other than polyester resin. Resins other than polyester are not particularly limited, and various resins can be used. For example, polystyrene, chloropolystyrene, poly-
α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer , styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer.

Styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylate copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylate copolymer, etc.) styrene-based resins (styrene or styrene-substituted ester copolymers) ), vinyl chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic acid resin, epoxy resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate Polymers, xylene resins, heat-melting resins such as polyvinyl butyral, and waxes such as natural or synthetic waxes are exemplified. These may be used alone or in combination.

The triboelectric charging member in the present invention is coated with a silicone resin containing an aminosilane coupling agent.

The aminosilane coupling agent used in the present invention has the following general formula.

A silane coupling agent represented by R□S i Yn may be used, and an aminosilane coupling agent particularly preferred for use in the present invention is one represented by the following structural formula.

H2NCH2CH2CH2Si (OCH-)3゜H2
NCH2C1(2C)12Si(QC21(5)3
,82Net(,CH2CH25i(QC)l,)2,
C113 1I2NCH2CH2N)ICt(2CH2CH2Si
(QC)l, ),,H2NC0NHCH2CH2C
) I, Si (QC2R5)3, H2NCH2CH2
NllCH2CH2CH2Si (OCII, )3,
H2NCH2CH2NHCH2C1 (2NHC) I2C
H2CH2・Si (OCH,), 1(s C20C
OCH2CH2NHCH2CH2CH2・Sx (OC
H-)3, HsC20COC)12CH2NHCH2C
H2NHCH2CH2・C) I2-5i (QC)1.
)3,H,C0COCH□CH2NHCH2CH2N)
IC1(2CH2C112・Si(OCH3),,H,
N-◎-5i (OCH,), .

◎-NHCH2CH2CH2Si (OCH,)3.8
2NC)12CH2NHC)I2-◎-CI(2Cl(
2.Sl (OCHi)□, (C4)1. )2NC
H2CH2CH2・Sx (OCHx )3, (C4H
,)2NCH,CH,C)I2・Si (QC,H,)
ff et al.

The alkoxy group of the above compound may be a chlorine atom.

These silane coupling agents may be used alone or in a mixed system of two or more.

The silicone resin containing the aminosilane coupling agent may be any conventionally known silicone resin, including straight silicone consisting only of organosiloxane bonds and silicone resins modified with alkyd, polyester, epoxy, urethane, etc. Can be mentioned.

In the above formula, R is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and R2 and R3 are a hydrogen group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a phenyl group. , phenoxy group, alkenyl group having 2 to 4 carbon atoms, alkenyloxy group having 2 to 4 carbon atoms,
Hydroxy group, carboxyl group, ethylene oxide group, glycidyl group or R9 0-5i R5 R9 R4, R9 are hydroxy group, carboxyl group, alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms, carbon Alkenyl group having 2 to 4 atoms, 2 to 4 carbon atoms
4 alkenyloxy group, phenyl group, phenoxy group,
k, 1. m, n, 0, and P represent integers of 1 or more.

In addition to unsubstituted substituents, the above substituents include, for example, an amino group,
It may have a substituent such as a hydroxy group, carboxyl group, mercapto group, alkyl group, phenyl group, ethylene oxide group, glycidyl group, or halogen atom.

For example, commercially available straight silicone resins include Shin-Etsu Chemical's KR271, KR255, and KR152, and Toray Relicon's 5R2400 and 5R2406.
Modified silicone resins include Shin-Etsu Chemical's KR206 (alkyd modified), KR520g (acrylic modified), and ESI.
Examples include oolN (epoxy modified), KR305 (urethane modified), S manufactured by Toray Silicone, R2115 (epoxy modified), and 5R2110 (alkyd modified).

All known carrier core materials can be used as the carrier core material, such as metals or alloys such as iron, nickel, and aluminum, particles of metal oxides or metal compounds containing these, and glass, silicon carbide, etc. particles are used.

Further, as the base material of the frictional charging member in the form of a sleeve or a doctor blade, conventionally used sleeves or doctor blades such as metals or alloys such as iron, aluminum, and stainless steel, and non-metallic compounds such as plastic and rubber can be used.

Note that the method for coating the surface of the triboelectric charging member with a silicone resin containing aminosilane is to add aminosilane to silicone resin, dissolve them in a solvent, and then add the aminosilane to the silicone resin.
Dipping, spraying, and
It is obtained by applying with a brush or the like and drying.

Further, the silicone resin may contain silica, silicon carbide, gold R oxide such as titanium oxide, carbon, carbon fiber, glass, etc. for reinforcement and friction prevention.
'Next, a specific manufacturing example of the triboelectric charging member used in the developing method of the present invention will be shown below.

Production Example 1 IOO parts by weight of toluene The above mixture was stirred with a homomixer for 15 minutes to prepare a coating layer forming liquid.

This liquid was applied to the surface of spherical iron powder with an average particle size of 100 μm using a fluidized bed coating device, and then baked at 2°0°C for 5 hours to give an average film thickness of 1. A coat carrier of OILm was obtained.

Production example 2 Silicone resin (KR250, Shin-Etsu Chemical ■) 1
00 parts by weight toluene
1.00 parts by weight of the above mixture was stirred for 15 minutes using a homomixer to prepare a coating layer forming liquid.

Apply this liquid to the surface of ferrite particles with an average particle size of 70 μm.
After application using a fluidized ball type application device.

It was baked at 250° C. for 2 hours to obtain a coated carrier with an average thickness of 1.2 μm.

Production Example 3 Using the same coating layer forming liquid as that used in Production Example 1, a coating having an average thickness of 5 μm (7) was formed on the toner transport member shown in FIG. 1 by dipping. After that, 250
The toner conveying member 2 shown in FIG. 1 was obtained by baking at .degree. C. for 5 hours.6 Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 100 parts of polyester resin (A) 10 parts of carbon These were melt-kneaded, then crushed and classified to obtain a toner having an average particle size of 12 μm. For this toner, a developer with a toner concentration of 2tzt% was prepared using the carrier of Production Example 1.

This developer was conditioned for 5 hours at low temperature and low humidity (10°C, 20%) and high temperature and high humidity (30°C, 90%), and the amount of charge was examined.The amount of charge was -27, 1μC/g, -, respectively. 26,
It was 3μc/g. Therefore, when images were produced using Ricoh's FT6080 in each environment, high image quality comparable to that at room temperature (20° C., 60%) was obtained.

Further, when a running test of 100,000 sheets was performed at room temperature and humidity, there was no decrease in the amount of charge even after 100,000 sheets, and the image quality was high without background smearing.

Example 2 Polyester resin (B) loop part carbon 10 parts With the above formulation, 12μ
A developer having a toner concentration of 3 wt% was prepared using the carrier of Production Example 2.

As in Example 1, using FT6080, tests were conducted at high humidity, low humidity, and a 100,000-sheet running test at normal humidity. As shown in Table 1, there was no decrease in the amount of charge at high temperatures, and even after running 100,000 sheets, the image quality remained as high as at the initial stage.

Comparative Example 1 A coated carrier having an average thickness of 1.0 μm was obtained in exactly the same manner as in Production Example 1 except that no aminosilane was contained.

Using this carrier, in the same manner as in Example 1, tests were conducted at high humidity, low humidity, and a 100,000-sheet running test at normal humidity. As shown in Table 1, the charge amount decreased significantly under high humidity, and the charge amount decreased after running 100,000 sheets, resulting in an image with a lot of scumming.

Comparative Example 2 Using the toner used in Example 2 and ferrite particles having an average particle size of 70 μm, a developer with a toner concentration of 3 tzt% was prepared.

Using this developer, a high-humidity test, a low-humidity test, and a running test at room temperature were conducted.

The results are shown in Table 1.

Example 3 Polyester resin (C) 80 parts Carbon 10 parts A 12 μm toner was prepared according to the above formulation, and the carrier of Production Example 1 was used to prepare a developer having a toner concentration of 2 νt%.

Table 1 shows the results of the high temperature, low humidity test and the running test at normal humidity.

Comparative Example 3 Polyester resin (C) 30 parts Carbon 10 parts A 12 μm toner was made using the above formulation, a developer with a toner concentration of 2 wt% was prepared using the carrier of Production Example 1, and a high temperature, low humidity test and a normal humidity test were carried out. A running test was conducted. The results are shown in Table 1.

Example 4 The toner used in Example 2 was placed in the electrophotographic component developing device shown in Figure 1, and the humidity was adjusted for 5 hours at high humidity and low humidity, respectively, and the toner was transferred from the toner conveying member 2 prepared in Production Example 3. The amount of charge on the toner was examined by suction. -12.7μc at high humidity
/g, and -13.4 μc/g at low humidity.

Also, after running 100,000 sheets at normal temperature and humidity,
As shown in Table 1, there was almost no decrease in the amount of charge, and the same high image quality without background smudge as the initial one was maintained.

Comparative Example 4 The toner conveying member 2 for a one-component developing device shown in FIG. 1 was produced in exactly the same manner as in Production Example 3 except that it did not contain aminosilane. Pour the toner used in Example 2 into this -component developing device.

An experiment similar to Example 4 was conducted. As shown in Table 1, the charge amount decreased in high humidity, and scumming occurred in the running test at room temperature.

〔effect〕

The toner has polyester resin as its main component, and IffF-
By coating the IFi imparting member with a silicone resin containing an aminosilane coupling agent, it is possible to prevent a decrease in the charge amount of the toner at high humidity, and to extend the life of the developer.

Furthermore, by setting the proportion of the polyester resin in the toner to 40% by weight or more, sufficient electrification can be obtained with the triboelectric charging member coated with silicone tallow containing an aminosilane coupling agent.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an electrophotographic apparatus used in Example 4 of the present invention and Comparative Example 4. 1... Electrostatic latent image carrier 2... Toner conveying member 3
・Elastic blade 4・・Sponge roller 5・・
・Agitating blade 6... Toner 7... Toner tank Patent applicant Ricoh Co., Ltd. -

Claims (1)

[Scope of Claims] 1. A developing method characterized by using a toner containing a polyester resin as a main component and using a triboelectric charging member coated with a silicone resin containing an aminosilane coupling agent. 2. The method according to claim 1, wherein the toner used contains 40% by weight or more of polyester resin.