JPS58132757A - Electrostatic image developer and image formation method - Google Patents

Abstract

PURPOSE:To obtain a visible image good in image quality, by developing an electrostatic image formed on an electrostatic image support with a developer contg. chargeable colored particles, and silica particles having surface silicon atoms having org. groups chemically combined through oxygen atoms with themselves. CONSTITUTION:A toner powder obtd. by dispersing colorant and, when necessary, additives into binder resin particles is mixed with finely divided silica particles subjected to hydrophobic treatment with an org. silicon compound having specified org. groups to form an electrostatic image developer. One of the org. groups is an optionally substd. aliphatic group having >=5 carbon atoms, or a group having a hydrocarbon ring and >=8 carbon atoms. It has another org. hydrophobic group having H, an optionally satd. aliphatic group, or a hydrocarbon ring. Said finely divided hydrophobic silica powder is added to the toner powder by 0.01-15wt% of the toner powder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer for developing electrostatic images formed in electrophotography, electrostatic recording, electrostatic printing, etc., and an image forming method using the developer. be.

At present, methods using electrostatic images such as electrophotography are widely used to form visible images from image information. In this method, for example, according to electrophotography, an electrostatic image formed on an electrostatic image support made of a photoconductive photoreceptor by a charging process and an exposure process is transferred to a photoreceptor made of electrodetectable colored particles (6). The toner image is usually transferred to a transfer material and fixed to obtain a visible image, while the electrostatic image support after the transfer is cleaned and used for the next image formation. Such a method allows repeated formation of visible images.

Therefore, in order to stably form a large number of visible images of good quality over a long period of time, certain conditions are actually required.
Developers used for developing electrostatic images are no exception. As an electrostatic image developer, one consisting of a powder of electroscopic colored particles (hereinafter referred to as "toner powder") consisting of a coloring agent dispersed in a binder resin has been praised. In order to form a high-quality visible image, it is necessary for the developer to have high fluidity, and for this purpose conventionally, fine powder of silicon dioxide has been added and mixed into toner powder. However, since the fine powder of silicon dioxide is hydrophilic as it is, a developer to which it is added causes blocking (agglomeration) due to moisture in the air, resulting in a decrease in fluidity. Therefore, it has been proposed to use (7) fine powder of silicon dioxide that has been subjected to hydrophobization treatment (Japanese Patent Laid-Open No. 46-5
782-'! (Refer to Japanese Patent Application Laid-open No. 48-47345 and Japanese Patent Application Laid-open No. 48-47346). Specifically, silicon dioxide particles and an organosilicon compound such as dimethyl dichloride are heated together with water vapor. Fine powder of silicon dioxide, which is made hydrophobic by reacting the silasol groups on the surface of silicon dioxide particles with an organosilicon compound, is produced by cocurrently blowing an inert gas such as nitrogen gas into a fluidized bed reaction vessel. used.

However, although these silicon dioxide fine powders have been made -6 hydrophobic, the degree of hydrophobization is not sufficient, and for example, in high temperature and high humidity, they become agglomerated and the fluidity of the toner deteriorates. starts to decrease.

Also, conventional hydrophobized silicon dioxide particles are quite hard and therefore easily damage the electrostatic image support. This is especially true when the electrostatic image support is made of a selenium-tellurium-based material or an organic photoconductive material, which has relatively low hardness.
) This is noticeable in some cases, and even when the material is made of a selenium-arsenic material, which is said to be relatively hard but extremely brittle against mechanical impact, it is also susceptible to similar damage.

Further, when the cleaning step of the electrostatic image support is performed by a contact cleaning method in which a cleaning member is brought into contact with the surface of the electrostatic image support, such as a blade cleaning method or a fur brush cleaning method suitable for high-speed cleaning. This phenomenon appears prominently. If this phenomenon progresses further, the blade or fur brush will be damaged, making it impossible to clean completely.

On the other hand, in order to prevent toner from adhering to the surface of the electrostatic image support and also to prevent damage to the surface, it is effective to add a friction reducer made of a fatty acid metal salt such as zinc stearate to the toner powder. It is known that there is
In this case, since the fluidity of the developer is considerably reduced, it is usually necessary to add fine powder of silicon dioxide as described above. However, when a toner to which fine powder of silicon dioxide is added together with a waxy friction reducing agent (9) as described above, there is a tendency to severely damage the surface of the electrostatic image support. This is especially true when the electrostatic image support is made of a selenium-tellurium based material or an organic photoconductive material, which has relatively low hardness, and when it is made of a relatively hard but brittle selenium-arsenic based material. This is noticeable when the cleaning method is a blade cleaning method or a fur book cleaning method.

As described above, some toners to which conventional hydrophobic silicon dioxide fine powder is added and mixed deteriorate their fluidity over a long period of time and cause agglomeration, as well as electrostatic charge image. As a result of damage to the support, it is not possible to stably form a large number of visible images of good quality over a long period of time.

The present invention has been made based on the above-mentioned circumstances, and the object of the present invention is to solve a large number of problems over a long period of time.
In the case of forming an image of a calyx, an electrostatic image developer capable of stably forming a visible image with good image quality (10) is provided.

Another object of the present invention is to provide an electrostatic image developer that does not deteriorate in fluidity and does not cause pro-2 kinging, and can always exhibit good characteristics, regardless of environmental conditions. .

Another object of the present invention is to consistently produce visible images of good quality even when a large number of visible images are formed over a long period of time in an image forming method that includes processes such as image processing, fixing, and cleaning. An object of the present invention is to provide an image forming method that can form images.

Other objects of the present invention To form a large number of visible images of good quality over a long period of time, regardless of the environmental conditions, cleaning method, type of electrostatic image support, etc. Kihru provides an image forming method that can perform the following steps.

Characteristics of Honjitsu vA developer: (11) It has electroscopic colored particles and a surface silicon atom to which a silicon atom having at least one organic group is chemically bonded via an oxygen atom. silicon dioxide particles, and the organic group is a saturated or unsaturated aliphatic organic group having 5 or more carbon atoms or an organic group having 8 or more carbon atoms having at least one hydrocarbon ring. The foundation lies in a certain point.

The method for forming acid in the form III of the present invention is characterized by electroscopically colored particles and silicon dioxide having a surface silicon atom to which a silicon atom having at least one organic group is chemically bonded via an oxygen atom. A step of developing an electrostatic charge image on an electrostatic charge image support with a developer containing particles to form a visible image, and a step of transferring and fixing the image to a transfer material. The organic group is a saturated or unsaturated aliphatic organic group having 5 or more carbon atoms or an organic group having 8 or more carbon atoms and having at least one hydrocarbon ring.

The present invention will be explained in detail below.

JP-A-58-132757 (4) In the present invention, a toner powder comprising a colorant and additives that can be added as necessary dispersed in binder resin particles is mixed with an organosilicon compound having a specific organic group. A fine powder of silicon dioxide obtained by hydrophobic treatment is mixed with Addition 71III to form an electrostatic image developer.

Here, the silicon dioxide fine powder is one in which a silicon atom having an organic group is chemically bonded to a surface silicon atom located on the surface of a silicon dioxide particle via an oxygen atom, and the organic group is R′ 81
group, RlR"Si group, or R"R2H"St group, R1 is a saturated or unsaturated aliphatic organic group having 5 or more carbon atoms, or R has at least one hydrocarbon ring. and is an organic group having a total number of carbon atoms of 8 or more.R or R is a hydrogen atom, a saturated or unsaturated aliphatic organic group, or a non-hydrophilic organic group having a hydrocarbon ring. In the case where R is a saturated or unsaturated aliphatic organic group, the number of carbon atoms may be 5 or more (13), preferably 6 or more, and more preferably 8 or more. %R'', R'' and R3 may be the same or different.

Such a fine powder of silicon dioxide is a fine powder of silicon dioxide in which both silicon atoms on the surface are silanol groups, RRR.
8iX, RR8iXxil, (qR”8iXs(X
represents a halogen atom. ) By reacting with an organosilicon compound represented by It can be obtained by combining. In this case, when the organosilicon compound represented by R"R"R"8iX is used, the mineral, etc.

The ion atom is one K of the surface silicon atoms of the silicon dioxide particle.
, is thought to be bonded via an oxygen atom, but RR8i
When using an organosilicon compound represented by It is thought that a reaction occurs in which the bonded material bonds with the silicon atom (14). Furthermore, when an organosilicon compound represented by R''5iXs is used, a more complicated reaction occurs.

Specific representative examples of the organosilicon compounds, which can also be referred to as hydrophobizing agents for silicon dioxide particles, explained above are as follows. Those represented by R"5i)l'a include octyl-trichlorosilane, decyl-trichlorosilane, nonyl-trichlorosilane, (4-1-propylphenyl)-)IJ dichlorosilane (4-t-)f
Ruanil) -to! j chlorosilane, and others, and those represented by R''R25iXz include cyhenthyrudichlorosilane, dihexyludichlorosilane,
Dioctyl-dichlorosilane/, nonyl-dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-
Butyl 7,nyl)-octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl+7-dichlorosilane, dinonenyl-dichlorosilane, cy-2-ethylhexyl-dichlorosilane, cy-3,3-methylpentyl-dichlorosilane, and others. , B,, "R2fL" 8 iX includes trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane, dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propyl 7, nil) -diethyl-chlorosilane, and others.

Regarding the synthesis method of the compound represented by one of the above, for example, R"R"R" 5tcz or Ba"R" 8iCjz, see, for example, the literature: Methoden der
Metalorganische Ver − in OrganischenChemie 1315
bindungen 8i (Houlen-Weyl
, GEORG THIEMEVIiRLAG ,
8TUTTGART (published in 1980) details the IC. The reaction of these 710 gene organosilanes with the silanol groups of silicon compounds is also described in detail in the same document, and those skilled in the art will have access to this useful book.

The fine powder of silicon dioxide has an average particle size of 1 to 10
Preferably, it is within the range of 0 mμ.

If the diameter exceeds 100 m, the electrostatic charge tends to damage the support, and if the diameter is less than 1 mμ, it is very easy to scatter and is difficult to handle.

In the present invention, the addition/mixing ratio #'i of hydrophobic silicon dioxide fine powder to toner powder is within the range of 0.01 to 15% by weight, but this is not absolute, and even if the ratio exceeds 15% by weight, This does not mean that the effect will be greater. Moreover, if it is less than 0.01 weight, no practical effect can be observed.

The toner powder in the present invention is not particularly limited, and any toner powder may be used.

Toner powder is usually made up of binder resin particles containing a colorant and additives dispersed therein, and the average particle size thereof is usually 5 to 30#.

Various resins can be used as the binder resin (17), but preferably styrene-acrylic resins, polyester resins, mixtures of these resins, and mixtures of these with other resins. A resin having a carboxylic acid or a derivative thereof in its molecule, such as resin, is used.

The reason why a toner powder containing a resin having such a carboxylic acid or a derivative thereof in its molecule as a binder resin is preferable in the present invention can be explained as follows.

That is, in conventional hydrophobized silicon dioxide, the degree of hydrophobization is insufficient and many unreacted silanol groups remain, or the substituents that have reacted with the silanol groups are small atomic groups as a whole. The hydrophilicity of other unreacted silanol groups is not covered, and therefore stable hydrogen bonds are formed between the silanol groups, carbonyl groups in the binder resin of the toner particles, and moisture in the environment. As a result, they are more susceptible to the effects of moisture. In contrast, in the silicon dioxide of the present invention, even if unreacted silanol groups remain (1B), the silanol groups react with other silanol groups because the substituents are large atomic groups. The toner powder made of the above-mentioned resin, which covers the hydrophilicity of the base and has outstanding properties as a binder resin of this type in terms of charging characteristics and durability, is used in a state where the adverse effects of moisture are prevented. As a result, by using the toner powder made of the above-mentioned resin in the present invention, the characteristics of the present agent as a whole can be greatly improved.

A polyester resin preferably used as a binder resin for toner is obtained by polycondensation of alcohol and carboxylic acid, and examples of the alcohol used include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol,
Diols such as 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butynediol, 1,4-bis(hydroquinomethyl)cyclohexane, and bisphenol A, hydrogenation (1
9) Etherified bisphenols such as bisphenol A1 polyoxyethylated, bisphenol A1 polyoxypropylene bisphenol A, and other dihydric alcohol monomers.

Examples of carboxylic acids include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sepacic acid, malonic acid, Examples include anhydrides of these acids, dimers of lower alkyl esters and lyluic acid, and other divalent organic acid monomers.

As the polyester resin used as the binder resin for toner, it is preferable to use not only a polymer made only of the above difunctional monomers but also a polymer containing a component made of trifunctional or higher polyfunctional monomers. be. Examples of such polyfunctional monomers, such as trivalent or higher polyhydric alcohol monomers, include sorbitol, 1,2.3.6-hexante F,
Roll, JP-A-58-132757 (6) 1.4-lupitane, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1
, 2.4-butanetriol, l.

2.5-pentanetriol, chrycerol, 2-methylglobantriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolethane, dimethylbenzene in 1,3.5-t'7hydro , and others.

In addition, as the trivalent or higher polyvalent carboxylic acid monomer, for example,
> 2.4-benzenetricarboxylic acid, 1°2.5-
Benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5.7-naphthalenetricarboxylic acid, 1,2.4-naphthalenetricarboxylic acid, 1,2,
4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2
-Methylenecarboxylic globan, tetra(methylenecarboxyl)methane, 1,2,7.8-octanetetracarboxylic acid, embol trimer acid, acid anhydrides thereof, and others.

(21) It is desirable that the above trifunctional or higher polyfunctional monomer component be contained in a proportion of 30 to 80 moles in each of the alcohol component or acid component as a structural unit in the polymer.

Polyester resin as a binder resin for toner is
Preferably, the chloroform-insoluble content is 5 to 25 m11117). The chloroform-insoluble content herein refers to the paper-unpermeable content when a sample is dissolved in chloroform, and is determined as follows.

Finely grind the resin sample, collect 5.00 g of sample powder that passed through a 40-mesh sieve, and use the filter aid Radiolite (φ7
00) 5.0og in a container with a capacity of 150-
100 g of chloroform was poured into this container, and the container was placed on a ball mill stand and rotated for 5 hours or more to sufficiently dissolve the sample in the chloroform. On the other hand, place a piece of paper (A2 paper) with a diameter of 7eIIM in a pressure filter, spread 5.00g of Radiolight evenly on it, add a small amount of chloroform, and filter. After loading, the contents of the container are poured into a filter. Another 1o container.

(22) Thoroughly wash with chloroform and pour into a filter so that no deposits remain on the walls of the container. After that, close the top lid of the filter and perform filtration. FMe141+
After the outflow of chloroform has stopped and the residue on the paper is washed, 100 - of chloroform is added as necessary, and the pressure filtration is carried out again.

After completing the above operations, place the paper, the residue on it, and the radiolite all on aluminum foil and put it in a vacuum dryer, and heat it at 80-100°C and 100mH pressure.
The total weight a(f) of the dried product thus obtained is measured, and the chloroform-insoluble content X (weight -) is determined by the following formula.

X (wt%) The chloroform-insoluble partial condensation polyester resin obtained in this way is a high molecular weight polymer component or a structured polymer component, and its molecular weight is approximately 2.
00,000 or more (23).

The proportion of the above-mentioned chloroform-insoluble components can be controlled to a considerable extent by appropriately selecting the reaction conditions or by allowing an appropriate crosslinking agent to exist in the reaction system in the polymerization reaction between alcohol and carboxylic acid mentioned above. can be formed with.

If a polyester resin with a chloroform-insoluble content of less than 5% by weight is used, the resulting toner will have a low offset generation temperature, and if a polyester resin with a chloroform-insoluble content of more than 25% by weight is used, the toner will have a high softening point. In either case, it is disadvantageous to fixing using a heating roller or the like.

It goes without saying that toner powders containing styrene resin, phenol resin, xylene resin, or other resins as binder resins can be used in the present invention, and provide greater benefits than when used in combination with conventional silicon dioxide fine powder. is obtained.

Here, the styrene resin includes a styrene homopolymer and a copolymer of styrene and other vinyl monomers. Other vinyl monomers include JP-A-58-1327
57(7) Ethylenically unsaturated monoolefins such as ethylene, flopylene, and imbutylene; Vinyl halides such as vinyl chloride, vinyl bromide, and vinyl fluoride; Vinyl esters such as vinyl acetate; Vinyl methyl ether, vinyl ethyl Vinyl ethers such as ether; Vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; N-vinyl compounds such as N-vinylpyrrole and N-vinylpyrrolidone; Acrylonitrile; Methacrylonitrile; Acrylamide or more. is used.

Among the above, for reasons related to the visible image forming process such as chargeability, durability, and developability, styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, or polyester resin is used as the main component (all binders are It is preferable to use a resin having a weight of at least 60% by weight of the resin as the binder resin for the reasons mentioned above, and furthermore, when fixing is by a contact heating type fixing method such as hot roller fixing, the above-mentioned copolymer resin is used. Even if there is, it is preferable that it further consists of a high molecular weight component and a low molecular weight component and has a molecular weight distribution such that two peaks appear in the molecular weight distribution (25) curve, or that it is crosslinked with a suitable crosslinking agent. . This is because toner powder made of a binder resin containing such a resin as a main component is less likely to cause the so-called offset phenomenon in fixing toner particles.

A coloring agent is dispersed and contained in the particles of the binder resin, but when producing a magnetic toner used as a -component toner, magnetic powder is contained instead of the coloring agent or together with the coloring agent.

As a coloring agent, carbon black, nigrosine dye (
C,1,n5o4ts B ), aniline blue (C,
I.

450405), Calco Oil Blue (C, 1, Aa
zoee Blue3), chrome yellow (α engineering, mu1
4090), ultramarine blue (C,1,mu77
103), Depon Oil Red (C, 1, A261
05), Kinori/Yellow (C, 1,447005)
, methylene blue chloride (C, 1, 452015)
, phthalocyanine blue (C, I.

A74160), malachite green offsalate (26) (C, 1,442000), lamp black (C, 1,
cliff? 7266), Rose Bengal (C, 1, A454
35), mixtures thereof, and others. These colorants need to be contained in a sufficient proportion to form visible scratches with a sufficient concentration, and are usually 1 to 20 parts by weight based on 100 parts by weight of the binder resin. .

Among the above colorants, carbon black is suitable for obtaining black toner powder, but acidic carbon black in particular can be uniformly dispersed in the binder resin at a higher content than other carbon blacks. ,
Therefore, it is preferable because a toner powder with a high degree of blackness can be obtained, but in a toner mixed with conventional silicon dioxide fine powder with a low degree of hydrophobization, the hydrophilicity of the unreacted silanol groups of the silicon dioxide is sufficient. Because the silanol groups are not cut into carbon lacquer, stable hydrogen bonds are easily formed between the silanol groups, the narbonyl groups or phenolic hydroxyl groups in the acidic carbon rack, and moisture in the environment. (27) For this reason, although acidic carbon black itself has many advantages, it has been difficult to contain a large amount of acidic carbon black. In the present invention, even if there are unreacted silanol groups, the hydrophilicity is covered and the silicon dioxide fine powder is used, which is highly hydrophobic. It is possible to contain carbon black.

In addition, in the above, when the acidic carbon black, ore, and sample were boiled in water and left to stand, the value of the supernatant liquid was 5.
It is a carbon black that has a carbon black of 0 or less.

The magnetic material may be a metal cap or alloy showing ferromagnetism such as ferrite, magnetite, iron, cobalt, or nickel, or a compound containing these elements, or a compound containing no ferromagnetic element but heated to an appropriate temperature. Alloys that exhibit ferromagnetic properties by being subjected to annealing, for example, manganese-copper-aluminum, manganese-steel-tin, etc., containing manganese and copper. Mention may be made of alloys of the so-called type, or chromium dioxide, etc. These magnetic substances are uniformly dispersed in the binder resin in the form of fine powder with an average particle size of 0.1 to 1 micron. And its content is toner 1
20 to 70 parts by weight per 00 parts by weight, preferably 40 to 7 parts by weight
It is 0 parts by weight.

Furthermore, examples of additives that can be contained in the particles of the binder resin include a charge control agent, an anti-offset agent when fixing is carried out by a contact heat fixing method, and others. Polyolefins, particularly polypropylene, having a softening point of 80 to 180 c'C are effective.

A toner constituting the developer of the present invention can be obtained by a mixture of the above toner powder and the hydrophobic silicon dioxide fine powder. Friction reducers can be added to prevent so-called toner filming.

There are various kinds of friction reducing agents, but various fatty acid gold (29) metal salts are suitable, and specific examples thereof include metal salts of maleic acid and zinc, magnesium, calcium, etc.;
Stearic acid and zinc, cadmium, barium, lead, iron,
Metal salts with nickel, cobalt, copper, aluminum, magnesium, etc.; dibasic stearate metal salts with nioleic acid and zinc, magnesium, iron, cobalt, copper, lead, calcium, etc.; palmitic acid with aluminum, calcium, etc. Lead caprylic acid; Lead caproic acid; Metal salts of linoleic acid with zinc, cobalt, etc.; Calcium ricinoleate: Metal salts of ricylic acid with zinc, cadmium, etc., and mixtures thereof. However, among these, zinc stearate and calcium stearate are particularly preferred.

The developer of the present invention is composed of the toner described above, but when the toner contains magnetic powder, the toner becomes a so-called one-component developer that can be used as is as a developer. Alternatively, this toner is combined with a carrier to form a so-called two-component developer. Here, as the carrier, iron (30) powder, glass beads, etc. are known, but butterfly, oxidized and unoxidized iron powder is preferably used as the conductive carrier, and as the insulating carrier, Preferably used are carrier core particles made of a magnetic material such as iron, nickel, cobalt, ferrite, etc. whose surfaces are coated with an insulating resin. It is also possible to compose the developer of the present invention with a mixture of two types of toner powders, both of which contain magnetic powder but each having a particle size of approximately KJ%.

In the image forming method of the present invention, an electrostatic charge image is formed on an electrostatic image support by a static charge forming method such as electrophotography, electrostatic recording method, or electrostatic printing method, and then developed with the above-mentioned developer. urge For example, in electrophotography, as shown in FIG. 1, an electrostatic charge is applied to the surface of a drum 1 made of a photoconductive photoreceptor that is rotated in the direction of the arrow by a charging mechanism 2 such as a corona charger. First, an optical image of the document is projected by the exposure mechanism 3 to form an electrostatic charge image, and this electrostatic charge image is filled with the above-mentioned developer and developed by a developing device 4 to form a toner image.

(31) As for the developing method, nine methods are used depending on the characteristics of the developer, and if the developer is a one-component developer, the so-called hair drying method, impression method, powder cloud method, etc. In the case of a two-component developer, the so-called magnetic brush method, cascade method, etc. are used.

The toner image thus formed is transferred onto a transfer material such as transfer paper. In the example shown in FIG. 1, the toner image is electrostatically transferred to the transfer paper that is synchronously conveyed along the transfer paper path P shown by the chain line by the action of the transfer discharge device 5. As the transfer means, various means such as pressure transfer and thermal transfer can be used. The transfer material to which the toner image has been transferred is then conveyed to a fixing device and undergoes a fixing process using, for example, a contact heat fixing method using a heating roller, thereby forming a visible image.

On the other hand, the electrostatic charge image support that has undergone the transfer process is subjected to a cleaning process after the static charge is removed, and then returned to the image forming process 1.
Served on 1. In the example of FIG. 1, the static elimination discharger 6
0 action causes the static charge on the drum l to disappear,
In the figure, a cleaning mechanism 7 using a fur brush
Toner particles remaining on the drum 1 are removed and cleaning is performed. Although the cleaning method here is arbitrary, it is preferable to use a blade cleaning method or a fur brush cleaning method that can reliably achieve the required cleaning, and can sufficiently cope with high-speed image formation. . The blade cleaning method is a method in which cleaning is performed by providing a scraping blade so that its tip edge contacts the surface of the electrostatic image support being moved, and has a simple structure and does not require energy. Further, the fur brush cleaning method is a method in which cleaning is performed by rotating a rotating brush so that the surface of the electrostatic image support is rubbed, and has the advantage of a large cleaning effect.

As described above, the present invention provides toner powder using fine silicon dioxide powder in which silicon atoms having a specific organic group are bonded to surface silicon atoms via oxygen atoms, thereby making it hydrophobic (33). The following effects can be obtained by using the toner developer obtained by adding and mixing the toner and the image forming speed by the scissors developer.

That is, as is clear from the description of the examples below, in the toner, sufficient fluidity can be obtained due to the physical properties of the silicon dioxide fine powder, and the fluidity can be maintained for a long period of time even in a high temperature and humid atmosphere. As a result, electrostatic charge images can be developed stably over a long period of time, with high resolution and sharpness. A large number of high-quality visible images can be stably formed.

Since the developer has great moisture resistance in this way, the conditions regarding the hygroscopicity of the toner powder itself are greatly relaxed, thus compensating for the weak point of the toner powder in that it has hygroscopicity. This allows the toner powder to fully exhibit its excellent properties. That is, the present invention provides a toner powder with relatively high AIII properties, for example (34), in which the main component of the binder resin is a hydrophilic resin such as polynisglu resin, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, etc. When using a toner powder that has many functional groups, or a toner powder that has a colorant that has many hydrophilic carboxyl groups and phenolic hydroxyl groups such as acidic carbon black,
It is particularly effective, and the reason is as described above.

Further, the developer of the present invention has a very small degree of damage to the electrostatic image support even when used for a long period of time, and therefore can retain the characteristics of the electrostatic image support for a long period of time. It is possible to stably form a large number of good visible images without fog or scratches. This effect is also greatly recognized when cleaning the electrostatic image support using a contact cleaning method such as a blade cleaning method or a fur brush cleaning method. Therefore, in the present invention, these contact cleaning methods are preferred as cleaning methods. By using the electrostatic charging method, it is possible to increase the image forming speed, specifically, the speed of the electrostatic charge support (35).

Furthermore, even when a wax-like friction reducing agent is added to the developer of the present invention, damage to the electrostatic image support is extremely low. By using the following, toner filming on the surface of an electrostatic image support can be prevented without causing any adverse effects.

Since the electrostatic image support is not damaged as described above, it is permissible to use materials that are easily scratched as the electrostatic image support. Alternatively, when a photoconductive photoreceptor made of a selenium-arsenic material, a photoconductive photoreceptor made of polyvinylcarbazole or other organic photoconductive material, etc. is used as an electrostatic image support, its service life is extended, and this Also, it becomes possible to form a large number of visible images of good quality over a long period of time.

In summary, in the present invention, the characteristics of the developer are improved and the electrostatic charge imparted to the image support by the developer is improved.
32757 (10), and as a result, various drawbacks that have been considered problems in the past are solved or alleviated, resulting in extremely great benefits in practice.

In the present invention, the reason why various excellent effects as described above are obtained is not necessarily clear, but the reason is that the silicon dioxide fine powder has silicon atoms bonded to the surface silicon atoms of the particles through oxygen atoms. Since the organic group is composed of a relatively large atomic group or a long chain atomic group, the degree of hydrophobicity of the silicon dioxide particles is considerably higher than that of conventional ones, and this imaging agent as a whole The moisture resistance of the silicon dioxide particles is greatly improved, and the surface of the silicon dioxide particles is in a state similar to being wrapped in a cushioning material, resulting in a decrease in surface hardness, and as a result, its action as a lubricant is sacrificed. One of the main reasons is that the damage force to electrostatic image supports etc. is significantly reduced without
It is thought that this is the case. Incidentally, in conventional hydrophobic silicon dioxide fine powder, the organic groups of the silicon atoms bonded to the surface silicon atoms of the particles/particles via oxygen atoms (37) have a small number of carbon atoms, and are therefore small. It is composed of atomic groups with short chains. However, in the present invention, the combined use of such conventional hydrophobic silicon dioxide fine powder is not prohibited.

Examples of the present invention will be described below, but the present invention is not limited thereto.

Polyester resins A and Bq used in the examples of the present invention were manufactured in the following Synthesis Example 1 and Synthesis Example 2, respectively.

Synthesis Example 1 Terephthalic acid 299f and polyoxypropylene (2,
2) -2,2-bis(4-hydroxyphenyl)propane 211F and pentaerythritol-#82t
A thermometer, a stainless steel stirrer, a glass nitrogen gas introduction tube, and a flow-down condenser were placed in a 99-bottomed flask, and the flask was set on a mantle heater L. Nitrogen gas was introduced from the nitrogen gas 4-person tube. The temperature was raised while keeping the inside of the flask in an inert atmosphere. Next, 0.05F of dibu(38) tyltin oxide was added, and the reaction was allowed to proceed at a temperature of 200° C. while monitoring the reaction at the softening point, thereby producing a polyester resin having a chloroform-insoluble content of 17 weight. This is called "containing polyester resin." Ring and ball softening point of this polyester resin A (JI8K 1351
- According to the method of 1960.

The same applies below. ) was 131°C.

Synthesis Example 2 Polyoxypropylene (3,3)-2,2-bis(4-
A polynisder resin with a chloroform-insoluble content of 12 weight was produced in the same manner as in Synthesis Example 1, except that 828 tons of (hydroxyphenyl)propane, 166 g of prephthalic acid, and 127 tons of benzene-1,2°4-tricarboxylic anhydride were used. . This will be referred to as "polyester resin B." The ring and ball softening point of this polynisl resin B was 125@C.

Example ■ Comparative toner I-, 1 Polyester resin A100 obtained in Synthesis Example 1 above
10 parts by weight of acidic carbon black "Mo-(39)" and 10 parts by weight of "LJ" (Cabot Co., Ltd. 11), and polypropylene "Viscol 660" as an anti-offset agent.
2 parts by weight of PJ (manufactured by Sanyo Chemical Industries, Ltd.) and fatty acid amide "
Hoechst Wax-CJ (Hoechst Japan 1m)
A toner powder having an average particle size IIs (hereinafter referred to as "toner powder I") was prepared by mixing 2 parts by weight of toner powder with an average particle size IIs according to the usual toner manufacturing method by heating, grinding, cooling, pulverizing, and classifying steps.

) was manufactured. Let this be "comparison)?-1-IJ."

Comparative Toner 1-2 Hydrophobic silicon dioxide fine powder with an average particle size of 20 mμ "Aerosil R-972J (manufactured by Nippon Aeshisil Co., Ltd., 70 to 80 of the silanol groups on the surface of bulk silicon dioxide particles are hydrophobized with dimethylsilane. ) to the toner powder f.
．． A toner was prepared by mixing them at a ratio of 8% by weight. This is referred to as "comparative toner (2)".

Comparative Toner I-3 ・Yukisono Surface K100A Akuri About 75% of the silanol groups on the surface of silicon dioxide particles having three silanol groups have been hydrophobized by reaction with propyl-dimethyl-chlorosilane, and the average particle size is A hydrophobic silicon dioxide fine powder of 20 mμ was obtained and mixed with toner powder I at a ratio of 0.8 weight to produce a toner. This is called “Comparison Toner 1-3”
Let it be J.

Comparative toner I-4 Glopyrudimethyl-penzyl instead of chlorine 2
Comparative toner 1-3 except that dimethyl-chlorosilane was used.
A hydrophobic silicon dioxide fine powder with an average particle size of 20 ms was obtained in the same manner as in the above, and the surface of the silicon dioxide particles was made hydrophobic. Manufactured. This is "Comparison Toner R-4"
shall be.

Tosu-1-1 to Tosu-Summer-10 Comparative Toner 1-3 was prepared in the same manner except that each of the organosilicon compounds shown in Table 1 below was used instead of propyl-dimethyl-chlorosilane. Hydrophobic silicon dioxide fine powder with an average particle size of 20 v*s was obtained, and each of them was mixed with toner powder l at a ratio of 0.8% by weight to produce a total of 10 types (41) of toners. Manufactured. These are referred to as "Toner 1-1" to "Toner I-10J".

Comparative toners I-1 to I-4 and toners I-1 to I-l shown in Table 1
A total of 14 types of developers were prepared by mixing 95 parts by weight of Yaria in spherical iron powder with an average particle size of 100A coated with styrene-acrylic resin to 5 parts by weight of each of -10. The fluidity and blocking properties were investigated using Ni (42), and these developers were applied to an electrophotographic copying machine rU-BbcVJ (manufactured by Konishiroku Photo Industries Co., Ltd.) equipped with a selenium-arsenic photoreceptor and a cleaning blade. Both copies were made on plain paper. The initial image quality of both copies obtained and the image quality after 20,000 copies were examined. The results are shown in Tables 2 and 3.

Evaluation of fluidity and blocking properties in the table was conducted as follows.

Fluidity: 2 from above in a container with a diameter of 50M and a capacity of 100
The toner powder was loosely packed through a 4-mesh sieve, and the weight was measured to determine the bulk density value. When the force density value is large, the toner fluidity is good, while when the bulk density value is small, the toner fluidity is poor.

Blocking property: The toner was left in an atmosphere of 55° C. and 30° humidity for 2 hours, and changes in the toner were examined. "○
” indicates that there was no change, “△” indicates that nodules were formed but collapsed when pressed with a finger, and “×” indicates that many nodules were generated, and these nodules collapsed even when pressed with a finger. It represents something that has not been done.

(45) Table 3 (The same applies below).

(46) Fog: Background reflection density was measured using a "Sakura Densitometer" (I) manufactured by Nishikata Photo Industries.

Problem: A problem in a halftone image, that is, the reflection density measured by Sakura Densitometer J (manufactured by J1 Hyakudai Photo Industry Co., Ltd.) is almost uniformly 0.
．． The occurrence of density unevenness and streaks in the large-area image showing No. 5 was investigated. "○" indicates that there was no density unevenness and there were hardly any streaks, "Δ" indicates that density unevenness and streaks were slightly observed, and "×" indicates that density unevenness and streaks occurred significantly. It means that there were many.

Line drawing quality: A first copy is obtained from a printed matter printed by printing type as a manuscript, this first copy is used as a manuscript again to obtain a second copy, and this operation is repeated in sequence to obtain the obtained result. Examine the contents of each copy of the file. "○" indicates that the text was clear even in the 7th copy, "Δ" indicates that the text was crushed and unclear in the 4th to 6th copy, and "x" indicates that the text was in the 1st to 3rd copy. The character ``gatsu'' (47) indicates that the character is blurred and unclear.

Example ■ Comparative toner It-1 Polyester resin B100 obtained in Synthesis Example 2
parts by weight, 15 parts by weight of acidic carbon rack "Mogul-LJ (Cabot Co., Ltd. 1m), and as an anti-offset agent [Hoechstwax-0PJ (manufactured by Hoechst Japan Co., Ltd.)]
3 parts by weight of toner powder with an average particle size of VK8111 (
Hereinafter, it will be referred to as "toner powder ■". ) was mixed with 0.2 weight of zinc stearate as a friction reducing agent for toner filming to produce a toner. this"
Comparison toner ■-1''.

Comparative Toner n-2 Toner powder (1) was mixed with 0.8% by weight of hydrophobic silicon dioxide fine powder [Aerosil R-972J (manufactured by Nippon Aerosil Co., Ltd.) having an average particle size of 20 mμ] to produce a toner. This is referred to as [Comparative Toner 11-24].

Toner 1-1 to Toner 1-10 A total of 10 kinds of toners were prepared by mixing various hydrophobic silicon dioxide fine powders and friction reducing agents shown in Table 4 with toner powder (1). These are "Toner Summer-1" ~ [Toner 1-
104.

The above comparative toners 1-1, l-2 and toners I-1 to 1
A total of 12 types of developers were prepared in the same manner as in Example 1 using Selenium-10, and these developers were used as a photoreceptor with selenium-
A copy image was formed in the same manner using an electrophotographic copying machine "U-BixVJ (manufactured by Koheiroku Photo Industry Co., Ltd.), which was the same as in Example 1 except that a tellurium photoreceptor was used. The initial image quality and the image quality after 10,000 copies were examined. The results are also shown in Table 4. In the table, ``5tZn J'' represents zinc stearate, and ``8tCa J represents calcium stearate.

(50) Example ■ Substitution with polyester resin OK, styrene, methyl methacrylate, and n-butyl acrylate in 80:5:15
Weight average molecular weight MW = 95,000, number average molecular weight Mfl obtained by copolymerizing at a ratio of (weight qk)
=9,500 styrene-methyl methacrylate)-
Toner powder (2) was produced in the same manner as toner powder (1) except that n-butyl acrylate copolymer resin was used, and using this, a total of 14 types of developers were prepared in the same manner as in Example I. When the image quality was investigated, the results showed almost the same tendency as in Example I9.

Example ■ A solution formed by dissolving Chlordiane Blue 4T, a bisazo pigment, in a mixed solution consisting of ethylenediamine 94J, n-butylamine 94WIt, and detrahydrofuran 212W was applied onto an aluminum drum with a diameter of 120 mm. A carrier generation layer having a thickness of 1-1 was formed. On the other hand, a pyrazoline compound, 1-7enyl-3-(p-diethylmethylaminophenyl)-5-(p-diethylaminophenyl )−
Pyrazoline 11.25F was dissolved, and the resulting solution was applied onto the carrier generation layer and dried at a temperature of 60"C for 1 hour to form a carrier transport layer with a thickness of 13μ. An organic photoconductive photoreceptor was produced.

This photoreceptor was attached to an electrophotographic copying machine (U-BixVJ) and the image quality of a good image obtained was examined in the same manner as in Example 2, except that a model was used. The results were obtained. From this, it is understood that the developing agent of the present invention is also effective for organic photoconductive photoreceptors.

Example V Polyester resin A 10 obtained from Synthesis Example IK above
0 parts by weight, 10 parts by weight of each of the carbon blacks shown in Table 5 below, and 2 parts of polypropylene "Viscol 6601" J (manufactured by Sanyo Chemical Industries, Ltd.) as an offset inhibitor.
Parts by weight and fatty acid amide “Hoechstowack-CJ (
A total of 10 kinds of toner powders with an average particle size of 10# were mixed with 2 parts by weight of Hoechstja, Inc., and 2 parts by weight of the powder and mixed with 2 parts by weight of Hoechstja, Inc., and mixed with 2 parts by weight of Hoechstja, Inc., and processed according to the usual toner manufacturing method through the steps of heating, kneading, cooling, pulverizing, and classifying. was manufactured. These 10 kinds of toner powders were mixed with hydrophobic silicon dioxide fine powder shown in the corresponding column of Table 5 below at a ratio of 1.0% by weight to produce a total of 10 kinds of toner powders.

A printing agent was prepared using these toners in the same manner as in Example 1, and a copy image was formed in the same manner, and the image quality after 20,000 copies was examined. The results are also shown in Table 5.

(54) As is clear from this result, the toner v-
1 to V-s are excellent, but comparison toners not according to the present invention V-t to V-Sa are inferior to 9 and 6.

Example ■ For each of the toners obtained in Example I, the initial image quality and the image quality after 30,000 copies were examined in the same manner as in Example ■ except that the cleaning mechanism was replaced with a fur brush cleaning made of acrylic fibers. However, similar results were obtained.

Example ■ Toner powder styrene and butyl methacrylate in a ratio of 65:35 (weight -
), 40 parts by weight of styrene-butyl methacrylate copolymer resin obtained by copolymerizing in the ratio of 10 parts by weight of [Ultrasen-630] (manufactured by Toyo W.Tatsu Kogyo Co., Ltd.) and polypropylene [Viscol 660 pJ (manufactured by Sanyo Kasei Co., Ltd.)
2 parts by weight and carbon black rMA-10oJ (5 parts by weight)
5) Mix 2 parts by weight of Nigrosine-based dye "Oil Black B8J (manufactured by Orient Chemical Co., Ltd.) and 1 part by weight of Nigrosine dye "Oil Black B8J" (manufactured by Orient Chemical Co., Ltd.), and perform the usual steps of heating, kneading, cooling, crushing, and classifying. According to the toner manufacturing method, the average particle size is 1r!1
A 7μ magnetic toner powder was produced. This is called "toner powder A."

Toner Powder B A magnetic toner powder was produced in the same manner as Mutsuwa toner powder B except that the ethylene-vinyl acetate copolymer resin was removed. This is called "toner powder B".

A total of 20 types of developers of the present invention were prepared by mixing each of the above toner powders K and toner powder B, and each of the same hydrophobic silicon dioxide fine powders as in toners I-1 to I-10 of Example I. The electrophotographic copying machine ``U-B4xT'' (
Konishi Roku Photo Industry Co., Ltd. M) is applied to form a copy image on plain paper. Initial image quality of the obtained copy image and 100
When I checked the image quality after 0 copying, I found that with all toners, there was no capri, and the image quality was poor, with no line drawings. When the image quality was examined in the same manner as above except that the cleaning mechanism was replaced with a magnetic blade, the same excellent results as above were obtained.

Example ■ In the production of toner powder, a phenolic resin with a ring and ball softening point of 130'C was used instead of polynisder resin, and neutral carbon black rRegal 660RJ (manufactured by Cabot Corporation) was used instead of acidic carbon black "Mogal-L". A toner was produced in the same manner as in toner 1-3 of Example I, except that the toner was used.

This is referred to as "toner -1".

Similarly, a sample of polyester resin A has a ring and ball softening point of 129.
A toner was produced in the same manner as in Toner I-3 of Example I, except that a xylene resin at 10°C was used and neutral carbon black "Regal 660RJ" was used instead of acidic carbon black "Mogull-L". [Toner V
Let it be ll-2J.

To 5 parts by weight each of the above toners I-1 and Vll-2,
Magnetite carrier 95 weight with average particle size 90J (
57) were mixed to prepare two kinds of developers. These developers were installed in an electrophotographic copying machine "U-BixVJ (manufactured by Konishiroku Photo Industries Co., Ltd.) K, and a copy image was formed on plain paper. When the developer using toner 1l-IK was used, 12.OOG copy The toner I-3 of Example I was obtained up to 0.000 copies, and the toner I-3 of Example I was obtained until 1000 copies. An image similar to that obtained when -3 was used was obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the structure of an electrophotographic copying machine that performs an electrophotographic process. 1... Dora person 2... Charging mechanism 3... Dew tip mechanism 4... Developing device 5... Transfer discharge @
6...Discharger for static elimination 7...Engraving of cleaning mechanism drawing (no change in content Procedural amendment C method) June 12, 1980 Commissioner of the Japan Patent Office Mr. Hiroki Shimada Indication of the case 1988 Patent Application No. 14731 2 Title of the invention Electrostatic image return agent teardrop H image forming method 3 Person making the amendment Relationship to the case Patent applicant 4, attorney 6 Number of inventions increased by the amendment 7 Subject of the amendment Procedural amendment (voluntary) July 24, 1980 Director-General of the Patent Office Kazuo Wakasugi Tono 1, Indication of the case Showa! s7 Patent Application No. 14731, Title of the invention Electrostatic Il developer and image melting method 3 Relationship with the person making the amendment Patent applicant evffi 1-1126-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo
(127) Konishiroku Photo Industry Co., Ltd. Kanesha 4
Agent 5 Date of amendment order 1) In the 7th line of page 113 of the specification, "(x represents a halogen atom.) JTh Correct as follows 0 "(XFJ Halogen atom, methoxy group, ethoxy group, propoxy group, 0) representing a propyloxy group, acetoxy group, amino group, etc. 2) Page 14, line 5 of the same is corrected as follows. ``For organic nitride compounds that can be called physical agents, it is preferable that Add the following: [Also, specific examples where X is other than a halogen atom and (cut
o), cH,8i CH,ell, CI'l,
NHCH, C horse NH. (CI'b O)m B l Cut C11b C1
12NHCHt CHl NH2J4) "HOIII@II J wo rHowb@Kasumi" in the 5th line from the bottom of page 15
I am corrected. 5) "Trioctyl-chlorosilane" in the 7th line from the bottom of the right column in Table 1 on page 41 of the same year is corrected to "octyl-trichlorosilane" 6) In Table 1 on page 41 of the same year, in the right column The second line from the bottom is corrected to "Didodecyl-dichlorosilane Jtr dodecyl-dichlorosilane." 7) In Table 2 on page 43, in the 7th line from the bottom of the second column from the left, "trioctyl-chlorosilane" is corrected to "octyl-silichlorosilane." . 8) In Table 2 on page 43, in the second row from the bottom of the second column from the left, "didodecyl-dichlorosilane" is corrected to "dodecyl-trichlorosilane." 9) In Table 4 on page 49 of the same page, 1 octyl-
Trichlorsilane,” he corrected. 10) In Table 5 on page 53, "dioctyl-dichlorosilane" in the 5th column from the bottom of 4II from the left was replaced with "octyl-dichlorosilane".
Trichlorsilane,” he corrected.

Claims (1)

[Claims] 1) Contains electroscopic colored particles and silicon dioxide particles having surface silicon atoms to which silicon atoms having at least one organic group are chemically bonded via oxygen atoms. The organic group is a saturated or unsaturated aliphatic organic group having 5 or more carbon atoms or an organic group having 8 or more carbon atoms and having at least one hydrocarbon ring. The charge is great. 2) The electrostatic charge agent according to claim 1, wherein the electrodetectable colored particles have an average particle size of 5 to 30 microns. 3) The electrostatic charge generating agent according to claim 1, wherein the silicon dioxide particles have an average particle size of 1 to 100 mμ. 4) The electrostatic charge developer according to claim 1, wherein the silicon dioxide particles are contained in an amount of 0.01 to 15% by weight based on the electrodetectable colored particles (2). 5) The electrodetectable colored particles contain a coloring agent dispersed in a binder resin, and the binder resin includes a polyester resin, a styrene-acrylic ester copolymer resin, or a styrene-methacrylic ester copolymer resin. The electrostatic image developer according to claim 1, which comprises the electrostatic image developer as a main component. 6) A patent in which the electrodetectable colored particles contain a coloring agent dispersed in a binder resin, and the binder resin contains as a main component a polyester resin containing 5 to 25 weight of chloroform-insoluble matter. An electrostatically charged developer according to claim 1. 7) Styrene-acrylic acid ester copolymer (3) body resin, wherein the electrodetecting colored particles contain a colorant dispersed in a binder resin, and the binder resin consists of a low molecular weight component and a high molecular weight component. The electrostatic image developer according to claim 1, which contains a styrene-methacrylic acid ester copolymer resin as a main component. 8) The electrodetectable colored particles contain a colorant dispersed in a binder resin, and the binder resin is a crosslinked styrene-acrylic ester copolymer resin or styrene-methacrylic ester copolymer resin. An electrostatic image developer according to claim 1, which contains as a main component. 9) The electrostatic image developer according to claim 1, wherein the electrodetectable colored particles contain a colorant dispersed in a binder resin, and the colorant is an acidic carbon black. 10) The binder resin is a polyester resin, a styrene-acrylic acid ester copolymer resin, or a styrene-acrylate copolymer resin.
The electrostatic image developer according to claim 8, which contains a methacrylic acid ester copolymer resin as a main component. 11) The electrostatic image developer according to claim 1, wherein the electrodetectable colored particles contain magnetic fine powder dispersed therein. 12) A developer comprising electroscopic colored particles and silicon dioxide particles having surface silicon atoms in which silicon atoms having at least one organic group are chemically M-grouped with oxygen atoms. The organic group includes a step of developing an electrostatic charge image on a charge image support to form a visible image, and a step of transferring the visible image to a transfer material, and the organic group has 5 or more carbon atoms. A saturated or unsaturated aliphatic organic group or an organic group having 8 or more carbon atoms and having at least one hydrocarbon ring. 13) The method for forming tiii grains according to claim 12, further comprising the step of cleaning the electrostatic image support with a blade or a fur brush. 14) Claim 12 or 13, wherein the electrostatic image support is constituted by a selenium-based photoconductive photoreceptor.
Image forming method described in section. (5) 15) The electrodetectable colored particles are formed by dispersing a coloring agent in a binder resin, the binder resin contains a polyester resin as a main component, and the coloring agent is acidic carbon black. The image forming method according to scope 14. 16) The method for forming an AII healthy acid according to claim 12, wherein the electrostatic image support is constituted by an organic monoelectric photoreceptor.