JPS59131944A - Electrostatic charge image developing carrier and its manufacture - Google Patents

Abstract

PURPOSE:To give sufficient durability and fluidity by forming a coating layer contg. a normal temp. hardenable silicone resin composed essentially of siloxane bonds on the surface of each carrier core particle. CONSTITUTION:Each carrier core is coated with an org. solvent soln. dissolving a normal temp. hardenable silicone resin, e.g. by a dipping, spraying, or fluidized bed method. The resin can be sufficiently hardened at <=150 deg.C. The preferable thickness of the coating layer is 0.1-20mum. A suitable silicon resin is a silicone varnish hardenable, e.g. at 20-25 deg.C and having 300-500,000mol.wt. and repeating units in the molecule, each represented by formula I or II in which X and Y are each H, halogen, OH, methyl, or methoxy; Z is methoxy or lower alkyl. As the carrier core particles, magnetic metals, steel, bronze, ferrite, carborundum, glass beads, SiO2, etc. are optionally usable. The diameters of these particles are 30-1,000mum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carrier for electrostatic images, i.e., a carrier that constitutes an electrostatic image developer together with a toner, and a method for producing the same.

In electrophotography, an electrostatic charge image is formed by applying a uniform surface charge to a photosensitive body made of a photoconductive element in a dark place and then exposing it to image light. A visible image is formed by developing.

Such an electrostatic charge image? Developing methods can be broadly classified into liquid developing methods and dry developing methods. The liquid development method is a method in which development is carried out using a liquid developer consisting of pigments and dyes dispersed as fine particles in an insulating organic liquid, and the dry development method is a method in which development is carried out using a liquid developer consisting of pigments and dyes dispersed as fine particles in an insulating organic liquid. This method uses a fine powder, usually called a toner, which contains a colorant such as black dispersed therein. The latter method involves charging the toner to a polarity opposite to that of the toner Y electrostatic charge image and electrostatically adhering it to the charged toner Y electrostatic charge image to form a visible image. This dry developing method uses a so-called one-component developer in which the toner is the only component, and a so-called two-component developer in which a carrier such as iron powder or glass beads is mixed with the toner. The former includes the bristle brush method, the impression method, and the powder cloud method, and the latter includes the magnetic brush method and the cascade method.

(3) By the above-described developing method, the visible image formed by toner adhering to the electrostatic charge image may remain on the photoreceptor as it is, or may be transferred onto paper or other image carrier. After being transferred, heat,
Electrodeposited by pressure, solvent vapor, etc.

The present invention relates to a carrier for a two-component developer used in the magnetic brush method or cascade method among the above-mentioned developing methods, that is, a carrier that is mixed with a toner and used for developing an electrostatic image. .

The electrostatic charge image developing carriers can be broadly classified into conductive carriers and insulating carriers. Oxidized or unoxidized iron powder is usually used as the conductive carrier, but developers containing this iron powder carrier have unstable gil friction properties with respect to toner, and developers that contain iron powder carrier The developer VCX has the disadvantage that fog occurs in the visible image formed.

That is, toner particles adhere to and contaminate the surface of iron powder carrier particles due to friction with the toner, so the electrical resistance of the carrier particles increases and the bias current becomes low.
944 (2) Furthermore, as a result of the triboelectric charging properties becoming more unstable, the image density of the visible image becomes low and fog increases. Therefore, is it possible to copy using an electronic copying machine using a visual agent containing an iron powder carrier? If this is done continuously, the developer deteriorates after a few copies are made, and it becomes necessary to replace it early, resulting in high costs.

On the other hand, a typical insulating carrier is a carrier in which a core particle made of iron, nickel, ferrite, or glass beads is laminated with a coating layer of YP3 edge resin on the other side. In a developer containing this insulating carrier component, it is less likely that toner particles will layer on the surface of the carrier particles and cause contamination, and it is possible to control the friction between the carrier and toner. It has the advantage of being particularly suitable for high-speed copying machines because of its excellent durability and long service life.

In this insulating carrier KN, the backing layer on the narrow surface of the core particle has sufficient i# resistance and the backing layer has sufficient adhesion to the core particle. It is important that the toner particles have (5) good anti-caking properties to prevent the toner particles from adhering to the surface of the carrier particles, and that the toner used with the carrier can easily be of the desired size and polarity. It is required that the charged state has a certain charging characteristic.

That is, the insulating carrier particles are rubbed against toner particles, other carrier particles, the container wall, etc. in the developing device, and when the coating layer is worn away from this friction (VC), the stability of the charging characteristics caused by the friction with the toner decreases. As a result, the toner cannot be charged to the desired state. Furthermore, if the adhesion force to the core particles is small, the above-mentioned friction causes the backing layer to peel off or break, resulting in the loss of the stable S-FdL characteristics.

Furthermore, when toner adheres to the surface of the toner layer, the frictional state changes and the characteristics of the filter layer become unstable.

In such a case, the entire developer must be replaced with a new one as soon as possible. Also, since the magnitude and polarity of the triboelectric charge generated on the toner depend on the magnitude and polarity of the electric charge generated on the carrier, what is the required charging state of the toner? In order to provide this, the incandescent carrier must have charging characteristics corresponding to this (6).

Although many types of insulating carriers have been proposed in the past, none of them satisfy all of the above requirements. For example, when used as a material for a general resin coating layer, the formation of a nonar film cannot be effectively prevented because its surface energy is large. As a countermeasure to this problem, it is conceivable to use a fluorine-containing resin such as Teflon, which has a small surface energy, as the material for the backing layer. However, since the fluorine-containing resin itself has low adhesion, its adhesion force to the core particles is lightless, and the resin is hardly soluble in most solvents. etc. are complicated and undesirable in terms of convenience and manufacturing.

Also, if we consider only the surface energy, silicon-containing resin is a good resin, and it is true that the resin has a wear resistance of 8.
It has excellent anti-solidification properties. Some examples of carriers having silicon-containing resins and fc-broken layers have actually been reported in some literature. However, when silicon-containing resin 'lf is used in the fracture layer, in order to cure the resin (7), it generally requires one heat treatment at 100°C or higher. It has the disadvantage of being limited to -4.

Specific examples of silicon-containing resins include unsaturated silicone resins, organosilicon, silanol, etc. described in U.S. Patent Application No. 3,562,533, which are mixed with acrylic resins and crushed. sterene-acrylate methacrylate shredded resin described in U.S. Pat. No. 3,627,522 and artificially edged with organosilane, silanol, silane, etc., U.S. Pat. No. 3,840 , No. 464, the nuclear particle consisting of glass beads? Treated with chromic acid, washed with water, dried, and then extracted with a mixture of trialkoxysilane and ether cellulose, U.S. Patent No. 3,849
, 127, and the glass beads described in U.S. Pat. No. 3,833,366. , J: Table of nuclear particles consisting of [silane, silanol, and siloxane compounds in f+ JP-A-59-131944 (3) ? Other methods have been proposed, including one in which the soil is soaked in water and then heated to form a strong ruptured membrane, and further an unsaturated polyester resin is formed on the soil to break the wax.

However, in order to complete the coating layer of these silicon-containing resins, a curing treatment is required at a high temperature of 300°C or higher for 1 to 3 hours. Compound @Y can be dissolved in only limited solvents.

7, it has excellent properties for carrier lamination! Characteristic improvers such as charge control agents with excellent performance that do not dissolve in specific solvents because they can only be used in specific solvents? It is not possible to make it contain 'f
Although c9 is a silicon-containing resin that is excellent for use as a carrier coating layer, it is weak against heat and cannot undergo curing reactions.9 A major drawback? have.

In view of the above points, the present invention has been developed as a carrier for developing electrostatic images, which has sufficient durability, is non-sticky, does not agglomerate, and has excellent fluidity (9) and has a significantly long service life. The first objective is to provide a method for producing the same.

The second object of the present invention is to form a coating layer on the core particles, so that the coating layer is not mechanically broken and peeled off. Provided are a carrier for developing an electrostatic image and ten manufacturing methods.

A third object of the present invention is to provide a carrier for developing electrostatic images that can prevent the formation of a film due to toner particles, and a method for producing the carrier.

A fourth object of the present invention is to provide a carrier for developing an electrostatic image that can be easily produced without requiring high-8 treatment when curing the broken pattern layer, and a method for producing the same. It depends on providing.

In the present invention, the object is achieved by forming a jelly containing a constantly curing silicone resin mainly composed of siloxane binders on the entrance surface of the carrier core particles.

Such an electrostatic charge Il! The carrier for development should not contain an excessive amount of solvent (1
0) A room-temperature curing silicone resin is coated on the surface of carrier core particles in a solution containing other additives, and then PFr is applied to the surface of the carrier core particles with a relatively low degree of gravitas as desired. It can be manufactured by evaporating and curing the room temperature curing type silicone resin. Here, the silicone resin is cured at a flow rate of less than 150'C, so that the blush becomes non-tacky.

The carrier of the present invention is not sticky, does not agglomerate, and has excellent fluidity. The problem is that the silicone resin that forms the plate itself has no viscosity and is difficult to form CML clumps, making it fluid (17).

This is because the silicone resin has been processed at a relatively low level and has a good surface shape. As a result,
The carrier of the present invention has very low incident energy and low coefficient of friction.

A carrier with low incident energy can prevent film formation by toner on the carrier surface during continuous copying in an electrophotographic copying machine.

In order to cure the above-mentioned room-temperature-curing silicone resin, high-temperature treatment and curing are not necessary, but it is possible to achieve sufficient curing at a high degree (11) of 150°C or higher, and it is possible to achieve sufficient curing by simply drying the solvent. As a result of the curing process being carried out at the same time, surprisingly young fruits are produced and excellent carriers can be obtained with great ease.

After curing, the silicone resin becomes non-depleted, but
After that, further heat treatment may be performed.

The room-temperature-curing silicone resin used in the present invention is a silicone resin that cures under normal operating conditions, for example, at a temperature of about 2 to 25°C, or at a temperature slightly higher than this temperature. Therefore, it is not necessary to exceed 100°C. (7) Room-temperature curing silicone resins are preferably those belonging to the silicone family, and silicone resins having a molecular weight of 300 to 500,000 are preferred.

This silicon face has repeating units represented by the following general formula CI) or (II) in its molecule.

JP-A-59-131944 (4) General formula CI) 10o -si +- General formula ["] -(-o -ss -+- -o-st-o- ■ In each formula, X8 and Y are hydrogen atom, halogen atom,
Hydroxyl group, methyl group or methoxy group; and Z
is a methoxy group or a lower alkyl group (for example, an alkyl group having from 1 to 4 carbon atoms).

Are there other resins for the above Tsunehata hardening silicone resins? May be mixed. Examples of such resins? To name a few, acrylic resin,
These include styrene resin, epoxy resin, urethane resin, polyamide resin, polyester resin, acetal resin, polycarbonate resin, phenol(13) resin, vinyl chloride resin, vinyl acetate resin, cellulose resin, polyolefin resin, and others.

These coplanar composite resins and blended resins may be used.

Specific examples of room temperature curing silicone resins that can be used in the present invention are shown below. 000-0-8i-
0-OH3 (14) (I-3) oii o Mw:6,
000-0-81-0- Hot OH3 (I-4) OCH30Mw#12,000 -o-st-o- OH3 (, l-5) OHOMw", 15,000 -0-8i-0- 0H5 (15 ) (I-6) H3 +5t-o-+-84W shi=;50,000R In addition to the above specific examples, for example, KR
-114, Kl (-220, KR-251, Klt-2
Those commercially available as 53°KR-255 or KC-88 (both manufactured by Shin-Etsu Chemical Co., Ltd.) can also be suitably used.

In the present invention, the carrier core particles include, for example, iron,
Magnetic metal such as nickel, Conort, steel, bronze, ferrite, Kerr 2 Random, glass beads, silicon dioxide, etc. Any item? can be used, and the particle size of the particles is 30
~1. u00 microns, preferably 50-500 microns.

In manufacturing the carrier of the present invention, a solution prepared by dissolving a room-temperature-curing silicone resin in a solvent, for example, a dipping method,
It is coated onto the carrier core particles by the SpV-method or the fluidized bed method. Other additives may be added to the solution as necessary.

JP-A-59-131944 (5) The fluidized bed method is suitable as the coating method. The organic solvent used here is arbitrary as long as it dissolves the resin, but examples include alcohols such as methanol, ethanol, and isopronozone, aromatic ashing X-based compounds such as toluene and yacinone, acetone, Ketones such as methyl ether ketone, tetrahydrofuran, dioxane, or a mixed solvent thereof may be used. After applying the solution to the core particles, it is usually heated and dried. The coating is then cured during and/or after drying.

It is sufficient for the positive temperature during this curing to be 150°C or less, and the curing temperature of Toyama hardening type silicone resin, which is particularly suitable, is 100°C.
(below).

When freeze-drying, do you use octylic acid, naphthenic acid, lead, iron, cobalt, manganese, zinc, etc.? It is effective to use it as a drying accelerator, and organic agnes such as ethanolamine are also effective.

In addition, in the present invention, even if the thickness of the temporary stock layer is relatively thin,
Also, is it inconvenient if it is too thick? Born 1,100 years ago.

(17) 0.1-20 microns is preferred.

The method for producing the carrier of the present invention using the fluidized bed method will be described below. 8 in a fluidized bed apparatus, and the rising pressurized gas flow generates carrier particles. It will rise without any loss of equilibrium. L7 will rise. 6CK @'+J g (Spoon the solution containing the hard ratio silicone resin from Hijikata until the tetranuclear particles become old and fall off.

This application is repeated and repeated to form a film with the desired thickness.

The toner to be used with the developer in conjunction with the carrier of the present invention is one in which a pigment and a dye are encapsulated in a resin. Examples of the pigment or dye include: blank, nigrosine dye (color index A30415B), aniline blue (color index A30405), calconyl blue (color index A Azoec Blue3), chrome yellow (color index Ma 14090), fulltramarine blue (color index A77i03),
Methylene Blue Eye (Color Index No. 16)
52015) Phthalosia (18) Ninblue (Color Index A7416o).

DuPont oil red (color index flat 2610)
5), Quinoline Yellow (Color Index 4470
05), malachite green oxalate (color index 7fL42ooo), lamp black (color index A77266), loin bengal (color index A45435) and mixtures thereof.

Styrene resins are mainly used as resins for toners, and styrene resins include styrene homopolymers and copolymers of styrene and other vinyl monomers. Other vinyl octads include unsaturated monoolefins such as ethylene, propylene, and isobutylene; vinyl halides such as vinyl chloride, vinyl bromide, and vinyl fluoride; vinyl esters such as vinyl acetate; and acrylics. Acrylic esters such as methyl acrylate, ether acrylate, and phenyl acrylate; Vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; Vinyl ketones such as vinyl methyl ketone and vinyl hexy(19) ketone; One or more of the following are used: a hevinyl compound such as lolidone; acrylonitrile; methacrylonitrile; and acrylamide.

Further, as resins other than steno-based resins, polyethene resins, polypropylene resins, vinyl ester resins, rosin-modified phenol-formalin resins, epoxy resins, and mixtures thereof can be used.

Embodiments of the present invention will be described below as a theory #4T, but the present invention is not limited to these ICs.

Example 1 E7 coating I was prepared by dissolving 10.9 ml of silicone resin K R-255 in 200 ml of methyl ether ketone. A coating solution of C was coated with a spherical steel plate with an average particle size of 100 microns using a fluidized bed apparatus, and 1 kg was coated with streaks, and dried at 40°C to form a liquid layer with a thickness of 2 to 3 microns. The carrier of the present invention having a strength of 1.710 was a non-adhesive carrier with good fluidity without agglomeration.

JP-A-59-131944 (6) Example 2 10.9' of silicone resin KR-220 and 10.9' of acrylic resin 1BR-80 (Mitsubishi Rayon Jl (a homopolymer of methyl methacrylate)) A coating solution was prepared by dissolving in 200 ml of methyl ether ketone.This coating solution was prepared using a spherical steel shot with an average particle size of 100 microns using a fluidized bed apparatus.
The carrier of the present invention was prepared by spraying 1.0 kg onto a 100 ml polyurethane powder and drying at 70 DEG C. to produce a carrier of the present invention having a thickness of 2 to 3 microns. This carrier was a non-adhesive carrier with good fluidity and no agglomeration.

Example 3 15. of silicone resin KR-251. ) i+, 3I of drying accelerator D-14 [manufactured by Shin-Etsu Chemical Co., Ltd.] and 5 g of nigrosine dye (color index A30415B)
A coating solution was prepared by dissolving the mixture in 200 ml of methyl ethyl chloride. This solution was sprayed onto 1 kg of spherical steel shot with an average particle size of lυO mikuan using a fluidized bed apparatus, and dried at 60°C to a temporary volume of 2 to 3 microns in thickness (21). The carrier of the present invention has been obtained. The carrier of the present invention thus obtained was a carrier with good fluidity that was neither sticky nor agglomerated.

Example 4 200 ml of cold-curing silicone resin KR-220 of 25.9 methylene ether ketone was prepared with a coating solution of 84 ml, and a semi-average particle size of 100 microns was prepared using this solution with a fluidized bed system @W. Spray on 1k1il of spherical steel shot, dry at 70℃ and break into 2-3 micron thick pieces.
A carrier of the present invention was prepared having a layer. This carrier was non-sticky, non-agglomerative, and had good fluidity. , .

Example 5 10g room temperature curing silicone resin KR-220h and 1
A coating solution was prepared by mixing 5 g of acrylic resin BR-80 with 200 ml of methyl ether ketone. This solution fluidized bed device @ Y has an average particle size of 1.0.
Spray 1 kg of 0 micron spherical steel shot,
The carrier of the present invention was prepared by drying at 10°C and having a thickness of 2 to 3 microns (22).

The obtained carrier γ had no stickiness, no agglomeration, and had good fluidity.

Agent ``P'' Person #' ffi #!, 2
・、.

Procedural amendment (method) February 10, 1980 Kazuo Wakasugi, Commissioner of the Patent Office1, Indication of the case: Patent Application No. 171279, filed in 19822, Title of the invention: Carrier for developing electrostatic images and its manufacturing method 3 , Name of the person making the amendment Name (127) Konishiroku Photo Industry Co., Ltd. 4 Name of agent (7875) Patent attorney Masahiko Oi Phone 824-2041 5 Date of amendment order January 31, 1980 6 Subject of amendment Full text of the specification 7, content of amendments Reprint of the specification (no change in content) -
537=

Claims (2)

[Claims] (1) The carrier core particles are coated with an ordinary hardening type silicone resin which makes the siloxane bond a living body. Y: Characteristic carrier for developing electrostatic images. (2) A method for producing a carrier for electrostatic image development, comprising a step of curing a room-temperature-curing silicone resin with a siloxane bond at the interface of the carrier core particles at a width of 150° C. or less.