JPS5981650A - Developer of electrostatic image - Google Patents

Abstract

PURPOSE:To obtain the developer of an electrostatic image capable of stably forming a good-quality visible image without deteriorating fluidity, etc. for a long period, by incorporating hydrophobic silica having a specified hydrophobic index or higher in at least one part of the surface. CONSTITUTION:Toner particles are prepared by dispersing colorants and necessary additives into binder resin particles. Fine silica particles are made hydrophobic by treatment using an org. silicon compd. having a specified org. group, such as propyl-trichlorosilane, dimethyl-dichlo-rosilane, or trihexyl-chlorosilane, silicon atoms each having org. groups are chemically combined with the surface silicon atoms located on the surface of each fine silica particle by the medium of oxygen atoms, and hydrophobic silica having >=50 hydrophobic index is thus prepared. This fine powder is added to toner powder and mixed to obtain an intended developer of an electrostatic image.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electrostatic image developer suitable for developing electrostatic images in electrophotographic copying, electrostatic recording, electrostatic printing, and the like.

Conventionally, methods using electrostatic images such as electrophotographic copying methods have been widely used to form visible images from image information. In this method, for example, according to the electrophotographic copying method, an electrostatic image formed on an electrostatic image support made of a photoconductive photoreceptor by a charging step and an exposure process is developed by a developing process made of electrodetectable colored particles. Developed with a toner f9
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. By such a method,
It can be repeated to form a visible image.

However, in order to stably form a large number of visible images of good quality over a long period of time, moderate conditions are actually required.
Developers used for developing electrostatic images are no exception. The electrostatic image developer is a powder of electrodetectable colored particles (hereinafter referred to as "toner powder") comprising a -1 colorant dispersed in a binder resin.

However, in order to form a visible image of good quality, it is necessary for the developer to have high fluidity, and for this reason conventionally a fine amount of silicon dioxide (silica) has been used. The powder is added to the toner powder and mixed. However, since the fine powder of silicon dioxide is hydrophilic as it is, the developer to which it is added causes blocking (agglomeration) due to moisture in the air, resulting in a decrease in flow rate of 1°F. Therefore, it has been proposed to use fine powder of silicon dioxide that has been subjected to hydrophobization treatment (JP-A-46-5782, JP-A-48-473).
No. 45, Japanese Unexamined Patent Publication No. 413-47346 (see each publication).

1. For example, silicon dioxide particles and an organosilicon compound such as dibutyl dichloride II are cocurrently fed into a heated fluidized bed reaction vessel with water vapor using an inert gas such as nitrogen gas. A fine powder of silicon dioxide is used, which is obtained by reacting the silanol groups on the surface of the silicon dioxide particles with an organosilicon compound and hydrating the particles by -1.

However, although these silicon dioxide 1) □, f, powders have been made to some extent hydrophobic, the degree of hydrophobization is not sufficient, and for example, convex '/A! In humid conditions, the fluidity of the toner decreases as it becomes more opaque.

Furthermore, the hydrophobized silicon dioxide particles used in the process are quite hard and therefore easily damage the electrostatic image support. This is particularly noticeable when the electrostatic charge image support is made of a selenium-tellurium-based material or an organic photoconductive material, which has relatively low hardness, and is said to be relatively hard. Similar damage is also likely to occur if the material is made of a selenium-arsenic material that is extremely mechanically fragile to impact. Further, the cleaning process 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 suitable for high-speed cleaning or a fur brush cleaning method. In some cases, this phenomenon becomes noticeable. Further, as this phenomenon progresses, the blade or fur brush is damaged, making it impossible to perform complete cleaning.

On the other hand, in order to prevent the toner from adhering to the surface of the electrostatic image support and also to prevent damage to the surface, a friction reducing agent consisting of a fatty acid metal salt such as zinc stearate is added to the toner powder. Although this is known to be effective, in this case, the fluidity of the developer is considerably reduced, so it is usually necessary to add the above-mentioned fine powder of silicon dioxide. However, when a toner containing a sock-like friction reducing agent and a fine powder of silicon dioxide is used, there is a tendency to severely damage the surface of the electrostatic image support. This is especially true when the electrostatic charge 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 selenium-arsenic material that is relatively hard but brittle. This is noticeable when the cleaning method is a blade cleaning method or a fur brush cleaning method.

As mentioned above, some toners to which JLT's fine hydrophobic silicon dioxide (silica) powder has been added and mixed may have their own fluidity decreased over a long period of time and may become agglomerated. As a result, it is impossible to stably form a large number of visible images of good image quality over a long period of time as a result of damaging the electrostatic image support.

The present invention has been made based on the following circumstances, and an object of the present invention is to maintain good image quality even when a large number of visible images are formed over the J and L periods. We present an electrostatic image developer that can stably form visible images.

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

These objectives are such that the developer according to the invention, in particular at least a portion of its surface, has a hydrophobicity index of 50 or more (
This is achieved using an electrostatic image developer characterized by containing hydrophobic silica (preferably 65 or more).

That is, the present invention provides a conventional developer using hydrophobic silica with a hydrophobicity (or hydrophobization) index (
(defined below) and by selecting the index in a specific range of 50 or more, they were able to more than successfully solve the above-mentioned problems. When the hydrophobicity index is set to 50 or more, the hydrophobicity caused by the hydrophobic group of silica (silicon dioxide) and the lubricant effect are effectively exhibited, which not only improves fluidity but also improves the Compatible material with improved stability in wet conditions and reduced abrasive force
In particular, the image support and the cleaning member) can be protected. On the contrary, the hydrophobicity of conventional hydrophobic silica (!1
．． The index is about 40 to 42, which is unsuitable because the polishing force is too strong and the fluidity is insufficient.

The term ``number of rows'' is defined as follows.

For example, pure water 5 (l m
j! and add 0.2 t: of silica. Soshi-
ζ、Magnetic stirrer ζ″While stirring gently,
Methanol is added from a bicollet tube whose tip is immersed in water at the time of dropping, and the number of milliliters of methanol taken when the floating silica begins to sink is defined as the hydrophobic tif number. In this case, methanol has a surfactant effect, and as the methanol is dripped, the silica that is suspended in water begins to sink (immediately 4) into the water via the methanol, so it has a large hydrophobic index (methanol The larger the amount of silica dropped, the greater the hydrophobicity of silica. In the present invention, hydrophobic silica with a methanol dropping amount of 50 mj!v1 (hydrophobicity index of 50 or more) is used, and it is contained in at least a small portion of the surface of the developer. , they succeeded in obtaining the above-mentioned remarkable effects that could not be achieved with conventional developers.

In the present invention, a toner powder obtained by dispersing a colorant and additives added as necessary in binder resin particles is hydrophobized with an organosilicon compound having a specific functional group. A fine powder of silica (silicon dioxide) is added and mixed to determine the composition of an electrostatic image developer.

Here, the fine silica 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. R'Si group, '
When expressed as R'R'Si group or R'R'R'5iJA, R1 is a saturated or unsaturated aliphatic organic group having 1 or more carbon atoms, or R' is at least 1
It may be a @樗 group having two hydrocarbon rings. In addition, W
Alternatively, R'' may be a hydrogen atom, a saturated or unsaturated aliphatic organic group, or a non-hydrophilic organic group having a hydrocarbon ring.

Further, R', R' and R3 may be the same or different.

In such a fine powder of hydrophobic silica, only one silicon element r on the surface is silanol. Powder to hydrophilic silica t%', r? 'R' R″S i X, R'R1S
i XJ L <HaR' S i
pu I + boxy group, propyloxy group, acetoxy W,
etc. ) reacts with organosilicon compounds shown in
1, R'R'R' Si '% is added to the silicon atoms on the surface of the silicon dioxide particles via the oxygen atoms.
or R" can be obtained by bonding and tightening the silicon atoms of the R2Si group or the R'Si group. In this case, when an organosilicon compound represented by R'R'R'S iX is used, the silicon It is thought that an atom is bonded to one of the surface silicon atoms of a silicon dioxide particle via an oxygen atom, but when an organosilicon compound represented by R'R'S i X) is used, two of the surface silicon atoms are bonded. In addition to the reaction of bonding to silicon atoms via oxygen atoms, it is thought that reactions of bonding with silicon atoms of other organosilicon compound molecules, or reactions of bonding with silicon atoms of those already bonded to surface silicon atoms, etc. occur.Furthermore, organosilicon If a compound of R' S i X,3 is used, a more complicated reaction occurs.

The above-described organosilicon compound which can also be called a hydrophobizing agent for silicon dioxide particles is preferably one in which X is a halogen atom, and specific representative examples thereof are as follows. Examples of R'5iXa include propyl-trichlorosilane, octyl-dichlorosilane, decyl-dichlorosilane, nonyl-trichlorosilane, (4-t-bribylphenyl)-trichlorosilane, (4-t-butylphenyl) )-trichlorosilane, and others, and those represented by R'R' Si -dichlorosilane, didodecyl-zig1J lucilane, dihexadecyl-dicrylsilane, (4-t-7'tylphenyl)
-octyl-dichlorosilane, dioctyl-dichlorosilane, dibutenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di-3,3-dimethylpentyl-dichlorosilane, and others, R'R)R 'S i There are Jiejiro Chlorsilan and others.

Specific examples of X other than a halogen atom include the following.

(Si11 rehearsal:) ] Si1lzt; I-h Si11
2 to 12-HCH2OCH3 1!1 (CH)O)3 S i CHλCHλCHkoOC-C
= CH Yu(CH3O)-CHls i Cf(-CH
-CHλNHCHλCHyuNH,1(CHiO)pS
I C'Hyu CH-CH2N HCI-IxCH-N
Among H2 or higher, for example, R'R2R'S i Cβ or R1R' S i CI! For the synthesis method of the compound represented by , x, see, for example, the literature: Methoden
der 0r((-anischen Chem
Metalorganis in ic 1315
che Ver-bindungen Si
(I(ouben-We-yl, GEORG THI
EME VERLAG.

5TUTTGΔRT published in 1980).

Furthermore, the reaction between these halogen-organosilanes and the silanol groups of silicon compounds is also described in the same document for the jT' phase, and those skilled in the art will be able to easily obtain useful products.

Conventional hydrophobic silica is considered to have, for example, the following structure on the surface side (hereinafter referred to as "dimethyl-substituted product").

CI:l Hz＼
/ This dimethyl-substituted product is made by reacting ordinary hydrophilic silica with dimethylsilane and bonding the alkyl group (methyl group) of this silane to the silica as shown in the following structure to make it hydrophobic. be. However, dimethyl substituted products that have been available since the beginning of the fit, such as R-972 (Roki Ae 1
(manufactured by Nozil), the proportion of hydrophobic silanol groups in hydrophilic silica is only 70 to 80%, and 20 to 3%.
0% of the silanol groups are substituted and remain in J', resulting in a hydrophobicity index of only 40-42.

On the other hand, the hydrophobic silica C used in the present invention has a hydrophobic index of 50 or more, for example, a hydrophobic index of 52 to 54 as shown below, and R-80 as a commercially available product.
5 (manufactured by Nippon Aerosil Co., Ltd.), hydrophobic index 65
R-812 and RX-30 are commercially available products.
There is 0. ) etc. are preferred. This R-805 is the above R-805.
In place of the dichlorodimedyylsilane used in the production of -972, at least a portion was treated with monoocdyltrichlorosilane, thereby introducing an octyl group having 8 carbon atoms (ctH 7-) into the silanol group. This is what I did. Therefore, the degree of hydrophobicity is improved compared to R-972. However, although the reaction was not sufficient and about 20% of unreacted silanol groups remained, the introduction of the octyl groups improved the overall hydrophobicity, resulting in a hydrophobicity index of 52 to 54. In addition, for R-812 and RX-300, the reaction of dimethylsilane, etc. used in the production of R-972, etc., is sufficiently advanced, and the reaction is carried out in a solvent such as toluene, dioxane, or tetrahydrofuran, which has been dehydrated with sodium metal. These R-812 and RX-300 partially have the following structure. It is considered that they have.

Here, as R, in addition to the above CHa-, CH9C
112-1CHtCH-CHy-1CHyoCHyuCH2
CHs- etc. are applicable.

In the hydrophobic silica that can be used in the present invention as described above, hydrocarbon groups (the above R', R', R+
or corresponding to R) are the same, the number of remaining silanol groups can be reduced by accelerating the reaction, or by increasing the number of carbon atoms in the hydrocarbon group, even if the number of silanol groups is the same. The hydrophobicity index can be adjusted to 50 or more, preferably 65 or more.

The hydrophobic silica fine powder has an average particle size of 1 to 10
It is preferably within the range of 0 mμ (preferably 5 to 30 mμ).

If it exceeds 100 mμ, there is a tendency to damage the electrostatic image support, and if it is less than 1 mμ, it is very easy to blow and lose and is difficult to handle.

In the present invention, the addition/mixing ratio of hydrophobic silica fine powder to toner powder is 0.01 to 15% by weight, but this is not absolute;
Even if the ratio exceeds this, the effect will not become greater. Further, if the amount is less than 0.01% by 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.

As mentioned above, the l.ner powder usually has a coloring agent and additives dispersed in particles made of a binder resin, and its average particle size is usually 5 to 30 microns.

Various resins can be used as the binder resin, but mainly styrene-acrylic resin, polyester-based 4M, 1M, mixed resins of these, and resins of these and other systems are used. Mixed tree of nh, J, eel,
A resin having a carboxylic acid or a derivative thereof in its molecule is used.

Yf
The reason why a toner powder containing a resin as a binder resin is preferable in the present invention can be explained as follows.

That is, in conventional hydrophobized silica, the degree of hydrophobization is insignificant, and many unreacted silanol groups remain, or the silica reacts with the silanol groups, causing one corner group of the device to become a whole. “
Since C is a small atomic group, the hydrophilicity of other unreacted silanol groups is not covered, and therefore, the silanol group and the carbonyl group in the B/F cedar resin of toner 1-y, Stable hydrogen bonds are formed with moisture in the environment, I'1. As a result, they are more susceptible to the effects of moisture. In contrast, in the silica of the present invention, even if unreacted silanol groups remain, the substituents that have reacted with other sinol groups are large atomic groups, so the hydrophilicity of the silanol groups is reduced. As a result, this type of binder 4M Jll has outstanding characteristics in terms of charging characteristics and durability, etc., and it is possible to use toner powder made of the above-mentioned resin while preventing the adverse effects of moisture. As a result, by using the toner powder made of the above-mentioned resin in the present invention, this characteristic of the developer as a whole can be greatly improved.

The polyester Jugeki, which is preferably used as a binder for toner, is obtained by polycondensation with an alcoholic acid. Examples of the alcohol used include ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1.
3-propylene glycol, ■,4-butanediol,
Neopendylgrini I-J, I,4-butenedio-t
Diols of 3, 1,4-bis(hydroxymethyl)
Etherified bisphenols such as Schiff 11, bisphenol A2, hydrogenated bisphenol A1, polyoxyethylenated bisphenol A1, polyoxypropylenated bisphenol A, and other dihydric alcohol monomers can be mentioned.

In addition, carboxylic acids such as mono-ζ include, for example, maleic acid, phosphoric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid,
Schiff L' hexanedicarboxylic acid, succinic acid, adipic acid, sebadic acid, malonic acid, anhydrides of these acids, dimers of lower alkyl esters and lyluic acid, and other divalent organic acid monomers. be able to.

Polyester resins used as binder resins for toners include not only polymers made only of the two difunctional monomers mentioned above, but also polyfunctional ones of trifunctionality or higher! ) It is also suitable to use polymers containing heavy components. Examples of such polyfunctional monomers, such as trivalent or higher polyhydric alcohol monomers, include sorbitol, 1,2,3.6-hexanetetrol, 1,4-sorbitan, and pentaeryst. diventaneerythritol, tribetaerythritol, sucrose, 1,2.4-butanetriol, Examples include 2.4-butanetriol, trimethylolethane, trimethylolethane, 1,3.5-)lyhydroxybutylbenzene, and others.

In addition, examples of trivalent or higher polyvalent carboxylic acid monomers include 1,2.4-benzenetricarboxylic acid, 1°2.5-benzenetricarboxylic acid, '1,2.4-cyclohexanetricarboxylic acid, 2, 5.7-naphthalene tricarboxylic fi, 1,2.4-naphthalene tricarboxylic acid, 1,2
．． 4-butanetricarvone m, 1. ．． 2.5-heki・ν
・Ntricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, embol trimer acid, and these acid anhydrides and others.

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

The polyester resin used as the inner resin for river use preferably has a chloroform-insoluble content of 5 to 25% by weight. Here is the chloroborum insoluble matter:
The filtration rate when dissolved in Iporn, I (E refers to the opaque content, and can be determined as follows.

Grind the resin sample (8) and collect 10 g of the sample powder (5.
100 g of chloroporum was poured into the container, and the sample was placed on a ball mill stand and rotated for 5 hours or more to sufficiently dissolve the sample in the chloroporum.

On the other hand, a filter paper with a diameter of 7 cm (tooth 2) was placed in a pressure filter, 5.00 g of Radiolite was pre-coated uniformly on it, and a small amount of glue Uroporum was added to make the filter stick tightly to the filter. Thereafter, the contents of the container are poured into a filter. Even more! Thoroughly wash with 5,100 ml of chloroform and pour into a ζ filter to ensure that no deposits remain on the walls of the container. After that, close the top lid of the filter and perform filtration. Filtration is performed under pressure of 4 kg/ti or less, and after the outflow of chloroform has stopped, 100 ml of chloroform is added to wash the residue on the filter paper.
Perform pressure filtration again.

After completing the above two operations, the filter paper, the residue on it, and the radiolite were all placed on aluminum foil and placed in a vacuum dryer at a temperature of 80 to 100°C and a pressure of 100°C.
Dry for 10 hours under +w*Hg conditions, measure the total weight of the dried solids a<g>, and calculate the chloroform insoluble content X (wt%) using the following formula.

X (wt%) In the case of polyester resin, the chloroform-insoluble content determined in this way is a high molecular weight polymer component or a crosslinked polymer component, and its molecular early number is approximately 12 (10,000 or more). It is believed that there is.

The above-mentioned chloroform-insoluble components can be removed by appropriately selecting the reactor ('l) or by adding an appropriate crosslinking agent to the reaction system in the polymerization reaction of alniol and carboxylic acid described above. By tightening it, it can be formed at a fairly controlled rate.

If a polyester resin containing less than 5% by weight or less of CI II form-insoluble matter is used, the toner will have a low offset onset temperature, and if a polyester resin containing more than 25% by weight is used, the toner will have a low softening point. In either case, it is disadvantageous for fixing using a heating roller or the like.

Furthermore, toner powder having a binder resin such as styrene resin, phenol resin, xylene resin, or other resin can be used in the present invention.
Larger benefits can be obtained compared to the case where it is combined with conventional silicon dioxide fine powder.

Here, the styrene resin includes a styrene homopolymer and a copolymer of styrene and other vinyl monomers. Other vinyl monomers include ethylene monomers such as ethylene, propylene, and isobutylene;
vinyl esters such as vinyl acetate; vinyl ethers such as vinyl butyl ether and vinyl ethyl ether; vinyl esters such as vinyl butyl ketone and vinyl hexyl ketone; ! - One or more of J-vinyl compounds; acrylonitrile; acrylonitrile; and acrylamide are used.

Among the above, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, or polyester resin is the main component for reasons related to the visible image forming process such as 4TL conductivity, durability, and developability. (60% by weight or more of the total binder resin) is preferably used as the binder resin for the reasons mentioned above,
Furthermore, when fixing is carried out by a contact heating type fixing method such as hot roller fixing, even if a double copolymer resin is used, it is further composed of component 1" f component and a low molecular weight component, and the molecular weight distribution curve is It is preferable that the toner has a molecular weight distribution such that two peaks appear, or that is cross-linked with an appropriate cross-linking agent. Yore(;1,
So-called ON 1 in fixing toner images! A coloring agent is dispersed in the particles of the Ba Cinder 411 fat.
．． When using toner, instead of colorant, use a certain number,
Magnetic powder is contained together with 16 coloring agents.

The MO agent ζ is carbon black, nigrosine dyeing agent.
I (C. 1. Iso.50415 B), Aniline Blue (C, 1. Tooth 5 (ll105), Calco Oil Blue (C.

l No. trzoe<, old (1e3), chromie l
:I-(C.l.

No. I4090), Ultramarine Blue (C.I.
1.11kt77103), Defbon Oil Red (C. 1. No. 26H15) - - Tonolin YetJ- (C.[, Interval 47005) 1,'
Chil/Nzoruk 1” Ride (C. I, N
o. 52015), Phthalocyanine Blue (C.
I, No. 74160), -l Lachite Green Oxalate (C. 1. Nu4200o),
Lamp black (C.I, No77266
), Rose Hengar (C. I, No. 454
35), mixtures thereof, and others. It is important that these colorants are contained in a sufficient proportion to form a visible image with sufficient concentration, and usually 1 to 20 parts by weight per 100 parts by weight of the Zuminder resin. It is considered to be the same.

Among the above-mentioned colorants, carbon black is suitable for obtaining black toner powder, but acidic carbon black is particularly suitable for dispersing uniformly in binder resin at a higher content than other carbon blacks. However, in the case of 1-L, which is mixed with conventional silicon dioxide j15) powder which has a low degree of hydrophobization, The unreacted silanol group of silicon dioxide has sufficient hydrophilicity
Two forces B - not because the silanol is violent,
Carbonyl group or phenol in acidic carbon rank (
The +1 hydroxyl group and the moisture in the environment are likely to form stable hydrogen bonds, which means that it is easily affected by moisture in the environment. Despite the fact that the acidic carbon black 4-III contained -υ, it was a national strength.

In line with this, in the present invention, unreacted silanol is also used (although its hydrophilicity is covered,
1. Since a fine powder of human-sized Rye 1 is used, a large amount of Rye 1 is contained in the toner particles without the above-mentioned adverse effects.
11. Possible to gelatinize carbon black-C
be.

Nayo) ゛, J': i J-, acidic carbon plastic,
Carbon black C is such that +i (+l') of the clear liquid when sample 1'1 is boiled in water C and left to stand.

I); 1 magnetite 1 is 1 body; 'ζ is ferrite, magnetite 1 with θ/i, ferromagnetic metal or alloy such as ferrite, cobal 1, nickel, or containing these elements. Compounds, some of which do not contain ferromagnetic elements (as appropriate)
i: Alloys that exhibit ferromagnetism through heat treatment, such as alloys called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, or chromium dioxide; Others can be mentioned. These magnetic materials have an average particle size of 0.1 to 1
Uniformly dispersed in the binder resin in the form of micron fine powder. The content of rough number J is 20 to 70 parts by weight, preferably 40 to 70 parts by weight, per 100 parts by weight of toner.

Further, as additives contained in the particles of the binder resin, there may be mentioned a charge control agent, an anti-offset agent when fixing is carried out by a contact heat fixing method, and others. For example, polyethylene fins, particularly polypropylene, having a softening point of 80 to 180°C by the ring and ball method are effective.

This toner is coated with friction (1!:
It is possible to add jλfII+. 1.1 There are various types of friction reducing agents, but various fatty acid metal salts are preferred, and specific examples include metal salts of maleic acid and zinc, magnesium, calcium, etc.;
Stearic acid and zinc, cadmium, barium, fLa,
Metal salts with nickel, cobalt, copper, aluminum, magnesium, etc.; dibasic lead stearate; metal salts with oleic acid and zinc, magnesylano2, iron, dibalt, copper, lead, calcium, etc.; palmitic acid and Metal salts with aluminum, calci, etc.; lead caprylate; lead caproate; metal salts of furinolic acid with zinc, cobalt, etc.; ricinol-doped calci 4 shim; metal salts of ricyl uric acid with zinc, cadmium, etc., and these Of these, zinc stearate and calcium stearate are particularly preferred.

The developer of the present invention is composed of the above-mentioned l/toner, but when the toner contains magnetic powder, the l/toner is used as a developer as is, so-called one component. Alternatively, this toner is combined with Ichiban, Toria, and Toria to form a so-called two-component developer.Here, iron powder, glass beads, etc. are known as carriers, but conductive As the magnetic carrier, oxidized or unoxidized iron powder is suitably used, and as the insulating carrier, the surface of carrier core particles made of a magnetic material such as iron, nickel, cobalt, or ferrite is preferably used. A developer coated with a resin is preferably used.Furthermore, in the image forming method using the developer of the present invention, which both contain magnetic powder and have similar particle sizes, electrophotographic copying method,
An electrostatic image formed on an electrostatic image support by an electrostatic image forming method such as an electrostatic recording method or an electrostatic printing method is developed with the above-mentioned developer. For example, in the electrophotographic copying method, as shown in the drawing, a charging mechanism 2 such as a corona charger applies a J:SFi11 charge to the surface of a drum 1 made of a photoconductive photoreceptor that is rotated in the direction of the arrow. , then exposure machine kill 3
The original light pickup image is projected and an electrostatic charge image is formed.
This electrostatic charge image is developed into a toner image by the developing device 4 filled with the above-mentioned developer.

Here, as a method of rendering, a method is used depending on the characteristics of the developer. If the developer is a one-component developer, the so-called Ani brush method, the impression method, the powder cloud method, etc. are used. 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 of the drawing, 'ζ is not shown as a chain line °C, and the toner image is electrostatically transferred to the copy paper being conveyed synchronously along the transfer paper passage 116 r' by the action of the transfer discharger 5. transcribed. As the transfer means, various means such as pressure transfer and heat transfer can be used. The transfer material to which the ζI/toner image has been transferred is then sent one step to a fixing device and undergoes a fixing process using a constant penetration method, for example, before contact with a heating roller, thereby forming a visible image.

On the other hand, the electrostatic image support that has undergone the transfer process is subjected to a cleaning process after being neutralized, and then subjected to an image forming process. In the example shown in the drawing, the static charge on the drums J and 11 is dissipated by the action of the static eliminating discharger 6, and
In the figure, a cleaning mechanism 7 using a cleaning blade is shown.
As a result, toner particles remaining on the drum 1''2 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 a scraping blade is provided so as to come into contact with the surface of the electrostatic image support whose leading edge is moved, and the structure is simple and energy is not required. The fur brush cleaning method is a method in which cleaning is carried out 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.

In the present invention, secondly,) a gay base metal r having a specific a mechanism is bonded to a surface silicon molecule Y via an oxygen atom, thereby making it hydrophobic (hydrophobicity index of 50 or more). The toner obtained by adding and mixing fine powder of silicon dioxide to toner powder wood has the following effects.

That is, as is clear from the description of the examples below, in the toner, one-minute fluidity can be obtained due to the physical properties of the hydrophobic silica fine powder, and the fluidity can be maintained for a long time even under high temperature and humid conditions. Therefore, it is possible to stably develop an electrostatic charge image with good quality, that is, with high resolution and sharpness, over a long period of time. As a result, a large number of visible images of good image quality can be stably formed over a long period of time.

``As the developer has great moisture resistance, the conditions for reducing the hygroscopicity of the toner powder itself are greatly alleviated, and therefore the hygroscopicity is weak a. It is possible to compensate for the weak points of the I-ner powder, and to fully exhibit the excellent properties of the I-suzu-powder.That is, the present invention provides an I-ner powder with relatively high hygroscopicity, For example, the main component of the binder resin is polyester resin, styrene-acrylate copolymer,
Toner powder containing many hydrophilic functional groups such as styrene-methacrylate copolymer, or toner whose colorant contains many hydrophilic carboxyl groups and soenol hydroxyl groups such as acidic carbon black. It is particularly effective when powder is used, and the reason is as described above.

Furthermore, 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 retains the characteristics of the electrostatic image support for a long period of time. This makes it possible to stably form a large number of good-quality visible images without fog or scratches.This effect can be achieved by 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, by utilizing these preferable contact cleaning methods as a cleaning method, it is possible to increase the image forming speed, specifically, the speed of the electrostatic image support. Become.

Even when a wax-like friction reducing agent is added to the developer of the present invention, the electrostatic charge image support is significantly less likely to be scratched. By adding a friction reducing agent consisting of a salt, toner filming on the surface of an electrostatic image support can be prevented without any adverse effects.

Since the electrostatic charge image support is not damaged by scratches, it is now permissible to use a scratch-resistant material as the electrostatic charge image support, for example in electrophotographic copying. is a photoconductive photoreceptor made of a selenium-tellurium-based substance or a selenium-arsenic substance, a polyvinylcarbazole or other organic photoconductive substance,
l-sexual photoreceptor, etc. Ii1! When used as a charge image support, its service life is extended, and in this respect, it is possible to form a large number of visible images of good image quality over a long period of time.In short, in the present invention, the development The properties of the developer are improved, the adverse effects of the developer on the electrostatic image support are eliminated, and as a result of these, various disadvantages that have been considered problems in the past are solved or alleviated, resulting in extremely great benefits in practice. is obtained.

In the present invention, the reason why various excellent effects as described above are obtained is not necessarily clear, but the reason why the fine powder of silicon dioxide can be obtained is that, for example, silicon atoms bonded to surface silicon atoms of the particles through oxygen atoms. Since the organic group contained in the silicon dioxide particles is composed of relatively large atomic groups or long-chain atomic groups, the degree of hydrophobicity of the silicon dioxide particles is considerably higher than that of conventional ones, and this imaging agent The overall moisture resistance 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 lower surface hardness.
One of the main reasons is thought to be that the loss couple force on the electrostatic image support etc. is significantly reduced without sacrificing the action as a lubricant. By the way, conventional hydrophobic silicon dioxide (IJ) is a silicon atom with a small number of carbon atoms (IJ), which is bonded to silicon atoms on the surface of its particles through oxygen (r). , vL are composed of short-chain atomic groups. In the present invention, the use of such conventional hydrophobic silicon dioxide fine powder is not prohibited.

J: Yes, this invention! I,! In addition to the above-described case in which the hydrophobic silica is distributed over the entire surface, the image 1 may be distributed only in the surface area (but at least in that part).

Examples of the present invention will be specifically described below.
J IJ Gorera ni IIJi! It is not determined.

Table 1 Various types of hydrophobic silica were prepared (all 11 silicas were manufactured by U-Zil Co., Ltd.) as shown in the following table. Four types of developer were prepared by adding 0.8% by weight each to a diameter of about 11.2 mμ). In order to evaluate the fluidity of these toners, static bulk density and hard bulk density were measured by a known method and are shown in Tables 2 below. In the measurement, for example, toner powder was poured into a container having a diameter of 28 mm and a volume of 100 mβ from above through a 100 mesh sieve, and the weight was measured to determine the static bulk density. Next, put the same lid on the container, tap it 300 times at a falling height of 5 degrees using a tapping device, and find the volume at that time.
The density P obtained by dividing the previously obtained weight by the volume was determined as the bulk density.

Table 2 In addition, 0.8% by weight of each of the above silicas was added to styrene-acrylic toner (average particle size 9.0μ), the bulk density was determined in the same manner as above, and this is shown in the table below. Ta.

Table 3 From the results in Tables 2 and 3 above, it can be seen that Dobu-- to which the hydrophobic silica of the present invention (R-805, R-812, RX-300) was added was different from that of the conventional hydrophobic silica (R- It can be seen that each bulk density is higher than the toner containing 972), and the fluidity is improved.

In addition, toner made of polyester (average particle size 9.1
The bulk densities of -972 and R-812 were measured in the same manner as above when various amounts of -972 and R-812 were added to mμ), and the results are shown in Table 4 below.

Table 4 According to this table, it can be seen that when the silica of the present invention is used, the fluidity of the toner can be improved even with a small amount added.

Next, each of the polyester toners used in the above fluidity test was applied to an electrophotographic copying machine f&IU-Bix450J equipped with a selenium-arsenic photoreceptor and a cleaning blade.
(Konishi Roku Photo Industry Co., Ltd. M) at 30℃, 80%R
Using I-1, 50,000 copies of images were formed on plain paper. Regarding the obtained copy image, the results shown in Table 5 below were obtained.

Table-5 *30. ．． From the results of 1,000 copies, it was found that the silica of the present invention (R-805, R-812
, RX-300), it is clear that the cleaning performance is improved and the change in the amount of charge is also small.

In addition, toners to which 100 silica was added with various addition amounts as described above were prepared using r[J-Bix450
(When this method was applied to J and 30,000 copies were made, the results shown in Table 6 below were obtained.

391 This result shows that the silica of the present invention is effective when added in small amounts.
This indicates that cleaning cycle performance is improved and damage to the cleaning blade edge portion is relatively less.

Next, 0.3% by weight of zinc stearate was added to each toner shown in Table 5, and using these toners, rU-B i x 3300MRJ (Konishi Roku Shagu- 3 (manufactured by a commercial company) at 30°C and 8 ()% RH.
When 1,000 sheets were printed, the result shown in Table 7 was 1':I.

Table 7 Note that blemishes are a phenomenon in which small black spots appear on the white background of the 21-bee as a result of poor cleaning.

From these results, it can be seen that when the toner of the present invention is used, no black bodies occur, and both cohesive force and fluidity are good.

[Brief explanation of the drawing]

The drawing is a schematic diagram of an electrophotographic copying machine that performs development using the toner according to the present invention. In addition, in the reference numerals shown in the drawings, 1---photosensitive drum 2----charging mechanism 3----ρW optical mechanism 4----developing device 7---cleaning mechanism P -・-This is the transfer paper path. Agent Patent Attorney Hiroshi Aisaka

Claims (1)

Claims: (1) An electrostatic image developer characterized in that at least a portion of its surface contains hydrophobic silica with a hydrophobicity index of 50,122 or higher. 2, ff1t! The electrostatic image developer according to claim 1, wherein the aqueous silica has a hydrophobic index of 65 or more.