JPS60112051A - Composition of electrophotographic developer - Google Patents

Abstract

PURPOSE:To obtain superior positively electrostatically chargeable developer without requiring addition of a charge controller by using a binder resin composed essentially of a specified polyester resin, and a copolymer of a hydrophobic monomer and a monomer contg. an amino group, and using a carrier coated with a vinyl chloride type copolymer. CONSTITUTION:A polyester resin is obtained by polymerizing an acid component consisting of bi-valent or higher valent carboxylic acid, its anhydride, or its lower alkyl ester, and an diol component represented by formula I in which R is ethylene or propylene group, x, y are each an integer of >=1, and the average value of the sum of them is 2-7. A copolymer is obtained by polymerizing with an azonitrile type initiator, a mixture of 95.0-99.95wt% hydrophobic copolymerizable monomer and 5.0-0.05wt% copolymerizable monomer having a tertiary amino group represented by formula II in which R1 is H or methyl, R2, R3 are each 1-4C alkyl or aryl, X is ester or amide, and n is an integer of 1-4. A binder resin consists of 10-50pts.wt. of said polyester resin and 50-90pts.wt. of said copolymer resin. A carrier is coated with a vinyl chloride- vinyl acetate copolymer in a weight ratio of (70-98):(2-30). Each of said polyester and said copolymer has a softening point of 100-180 deg.C. As a result, a sharp image free from background stains can be obtained and storage stability of an image stored in a file made of PVC is good.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer composition for developing electrostatically charged images in electrophotography, electrostatic recording, electrostatic printing, etc., and more specifically, a developer composition containing a positively charged toner. Regarding.

Conventional electrophotographic methods include methods such as those described in U.S. Patent Nos. 2,297,691 and 2,557,809.
By uniformly distributing the photoconductive insulating layer, exposing the layer to light, and dissipating the charge on the exposed portions, a latent image is formed; Visualization is achieved by attaching a colored, electrically charged fine powder called toner (development process), and the resulting visible image is transferred to a transfer material such as transfer paper* (transfer process), heating, and pressure. Alternatively, it consists of a step of permanently fixing (fixing step) by another suitable fixing method.

Furthermore, when zinc oxide or a sensitive compound-based material is used for the photoconductive insulating material, a positively charged toner is used in a regular development method such as in a copying machine.

On the other hand, even in the case of a selenium-based photoreceptor, in which a negatively charged toner is used in a normal development method, a positively charged toner is used in a reversal development method such as a laser beam printer.

In this way, the required performance of toner is not limited to just the developing process.
It must be able to perform the functions required in each step of the transfer process and the fixing process, and it largely depends on the type of photosensitive material used in the photoconductive insulating layer.

Generally, toner is subjected to mechanical frictional force due to shearing force and impact force during mechanical operation in a developing device, and deteriorates during copying of tens to tens of thousands of sheets. To prevent such toner deterioration, it is best to use strong resins7 with large molecular weights that can withstand mechanical friction forces, but these resins generally have a high softening point and cannot be used in oven fixing, which is a non-contact fixing method, or infrared rays. With radiant fixing, the thermal efficiency is poor, so fixing is not sufficient, and the contact theorem method has good thermal efficiency, so it is difficult to fix widely (
Even with the heat roller fixing method used, it is necessary to raise the temperature of the heat roller to achieve sufficient fixation, which can lead to problems such as deterioration of the fixing device, curling of paper, and increased energy consumption. (If such a resin is used, the production efficiency will be significantly reduced when it is pulverized to produce toner. Therefore, if the polymerization degree and softening point of the binder resin (binding resin) is too high, the I can't.

On the other hand, the heat roller fixing method has extremely good thermal efficiency because the surface of the heating roller and the toner image surface of the sheet to be fixed come into pressure contact (and is widely used from low speeds to high speeds,
When the heating roller surface and the toner image surface come into contact, a so-called offset phenomenon tends to occur, in which the toner adheres to the heating roller surface and is transferred to a subsequent transfer paper or the like. In order to prevent this phenomenon, the surface of the heating roller is treated with a material with excellent mold release properties such as Z-filter resin, and in addition, the surface of the heating roller is coated with silicone oil or the like to prevent the ℃ offset phenomenon. Completely prevented.

However, the method of applying silicone oil, etc.
The fixing device is not only large and expensive, but also has multiple mVc, which tends to cause trouble (which is not preferable).

In addition, as described in Japanese Patent Publication No. 55-6895 and Japanese Patent Application Laid-open No. 56-98202, there is a method to improve the offset phenomenon by widening the molecular weight and distribution width of the binder resin, but the degree of polymerization of the resin is high. Therefore, it is necessary to increase the fixing temperature.

As a further improved method, as described in Japanese Patent Publication No. 57-495, Japanese Patent Application Laid-Open No. 50-44856, and Japanese Patent Application Laid-open No. 57-37555, the offset phenomenon is improved by making the resin asymmetrical and crosslinking. There is a method, but the fixation point has not been improved.

In general, the minimum fixed swamp temperature is between the temperature offset and the hot offset, so the usable temperature range is between the minimum fixed swamp temperature and the hot offset, and it is necessary to lower the minimum fixed temperature as much as possible. By raising the low-hot offset temperature as much as possible, the fixing temperature used can be lowered and the usable temperature range can be expanded, resulting in energy savings, high-speed fixing, and prevention of paper curl. Also, double-sided copying is troublesome (because it is possible, there are many advantages such as making the copying machine more intelligent, controlling the temperature of the constant N device to 8 degrees, relaxing the tolerance range, etc.).

Therefore, resins and toners with good fixing properties and offset resistance are always desired.

In addition, in the case of a two-component development system, the sharpness of the toner, the durability of the developer, and the image quality depend heavily on the performance of the carrier (for this reason, the image quality is improved by coating the carrier surface with resin. However, most of them are related to negatively charged toners, and only a few are related to positively charged toners (and almost none with sufficient performance for practical use are known). A common method is to knead a charge control agent into the toner, but it is black and is not suitable for color printing, transfers to vinyl chloride sheets, and has a wide charge distribution (which results in image deterioration). There are disadvantages such as fast transfer of toner to the fixing roller and offset.

Therefore, there has been a strong desire for a carrier coat material suitable for positively charged toner that provides clear copy images and does not cause image deterioration in terms of durability. In addition, copies are very often stored in notebooks, filing cases, etc. that use soft PVC sheets, but in most cases, the toner adheres to the sheet and does not peel off or the image transfers, which is not only undesirable but also difficult to store indoors. It is also necessary to choose a material that does not allow toner to adhere to the interior of the printer.

The present invention has been made to meet these requirements, and its purpose is to uniformly and positively charge light without using additives such as charge control agents, and to eliminate stains and stains on copied images.
To provide a developer capable of obtaining sharp images without missing solid black areas, bleeding, etc.

Another object of the present invention is to provide a developer composition with excellent durability.

Another object of the present invention is to provide a developer which prevents the offset phenomenon by applying an anti-offset liquid in a heat roller fixing system and which can be fixed at a lower fixing temperature.

Is there another purpose of the present invention as a charging agent such as a charge control agent? To provide a clear color toner that is positively charged even when not in use.

Another object of the present invention is to provide a developer that does not transfer images to vinyl chloride sheets or the like.

The present inventors have arrived at the present invention as a result of intensive research to achieve the above object. That is, the present invention provides a developer composition comprising a binder resin, a colorant, and a carrier, in which the main components of the binder resin are (Al, a diol component represented by the following general formula tIl, and a divalent or higher polyhydric carboxylic acid, or 10 to 50 M% of a polynisglu resin obtained by t-polymerization with an acid component consisting of an acid anhydride or a lower alkyl ester thereof, and 95.0 to 99.95 parts by weight of a H3 (Bl hydrophobic copolymerizable monomer). A mixture of 5.0 to 0.05 parts by weight of a copolymerizable monomer containing a 6th-class amino group represented by the following general formula (6) was mixed with an IJ type initiator. The present invention relates to a positively charged electrophotographic developer composition comprising 50 to 90% by weight of a resin obtained by using $1,000 and a carrier coated with a vinyl chloride-vinyl acetate copolymer resin. .

The diol component represented by the general formula [υ] used in the polyester resin (Al) in the present invention includes polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)cropane, polyoxypropylene (
5,5) -2,2-bis(4-hydroxyphenyl)
Propane, polyoxyethylene (2,0) -2,2-
Bis(4-hydroxyphenyl)propane, polyoxypropylene (2゜polyoxyethylene (2,0)
Examples include -2,2-t's(4-hydroxyphenyl)propane, polyoxypropylene + 61-2,2-bis(4-hydroxyphenyl)propane, etc., and these may be used alone or as a mixture of several types. You can use it.

In addition, other polyols, such as polyoxypropylene H-2,2-bis(4-hydroxyphenyl)propane, polyoxyphenylethylene (3]-2,2-
Bis(4-hydroxyphenyl)propane, glycerin, polyoxyethylene (6) chrycerin, polyoxypropylene α4-pentaerythritol, etc. cannot be added to the polyol component in an amount of about 10 mol% or less, but polyoxyphenylethylene +31-2.2-Bis(4-hydroxyphenyl) three-dimensional structure like furopane! If the reaction is difficult to proceed with harmful substances, please be careful when using highly hydrophilic polyols such as glycerin, polyoxyethylene (6) and pentaerythritol, as they tend to have poor image quality. It takes.

Examples of divalent or higher carboxylic acids that can be used in the polyester resin + AI of the present invention include fumaric acid, maleic acid, fucuric acid, phosphoric acid, in-octyl phosphoric acid, trimellitic acid, pyromellitic acid, 6- indecenyl-1,2,
Examples include 5,6-hexanetetracarboxylic acid, and the ratio of the acid component to the alcohol component is 0.8 to 0.8 when used alone or in a mixed system.
It is preferably 1.2, more preferably 0.9 to 1.1.

In addition, the ring and ball softening point (ASTM) of polyester resin + AI
E28-51T) is preferably 100°C to 180°C.

The hydrophobic copolymerizable monomers used in the resin of the present invention (Bl include styrene, α-methylstyrene L/7, vinyltoluene, dimethylstyrene, and other styrenic monomers, n-butyl acrylate, acrylic acid) 2-ethylhexyl, n-butyl methacrylate, 1so-butyl methacrylate,
Examples include (meth)acrylic acid ester monomers such as lauryl methacrylate.

In the present invention, copolymerizable monomers containing a tertiary amino group represented by the above general formula used in the resin (Bl) include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and diethylaminoethyl acrylate. , dimethylaminopropyl methacrylamide, etc. In the present invention, polyester resins (Al,
If necessary, a small amount of resin 14i, which is commonly used in Bl, can be added to the resin without any problem.

In the present invention, the azonitrile polymerization initiators used in the resin (Bl) include azobisinbutyronitrile, azobisdimethylvaleronitrile, azohis(2,4-dimethyl-4-methoxyvaleronitrile), 2 , 21-azobis-2,3-dimethylbutyronitrile, 2,2I-azobis-2!+5*3-)dimethylbutyronitrile, 2.
2'-Azobis-2-incrovirbutyronitrile, i
, i'-azobis-1-(2-methylcyclohexane)
etc. In addition, the ring and ball softening point of the resin (Bl) is 10
0 to 180°C is preferred.

Coloring agents used in the present invention include carbon blank, acetylene black, phthalocyanine blue, Rhodamine B base, Nlube/Trend 49, Bulben Trend 146, etc., and are usually used in amounts of 1 to
15 weight 56 used.

The carrier used in the present invention is coated with a vinyl chloride-vinyl acetate copolymer resin. Preferably, the resin is
In order to improve the adhesion of the coating film to the core, a portion of the vinyl acetate unit may be hydrolyzed, or a copolymerizable monomer having a carboxyl group may be copolymerized within 5 wt%. The vinyl chloride-vinyl acetate joint resin has a glass transition point (Tg, °C) of 70\80'C,ajl'
Those having a uniform molecular weight of i5,000 to so, o o o are preferred. As the carrier used in the present invention, well-known carriers can be used, including magnetic materials such as iron, ferrite, steel, magnetite, and nickel, and glass.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example-1 Polyoxyethylene (2,2) -2,2-bis(4-
Hydroxyphenyl) propane 2800g, polyoxyethylene (21-2,2-bis(4-hydroxyphenyl)propane 6509.
Polyester resin obtained by polymerizing and condensing 24g (resin ■; bulb softening point 152℃, Tg 62℃, acid value 22,
[]) 4 parts of snoII, α-methylstyrene 7009. Butyl acrylate 280
,9. 1 205' of dimethylamine ethyl meccrylate
Resin obtained by polymerization with 0 J/ of azobisin butyronitrile (Resin ■; Softening point: 1-6°C, Tg: 68°C
) 48 parts, carbon blank (manufactured by Cabot Corporation)
A 7-liter portion of Gal 400R) was milled using a ball mill, melted and mixed using a kneader, and then ground using a jet mill to obtain a toner having an average particle size of 13 μm.

Carrier iron powder (EFV 250/400) 3000g
Vinyl chloride and vinyl acetate (weight ratio 90:10,
Number average molecular weight 12,000) 150.9) was dissolved in 1k of toluene and added to the set quenching solution, stirred at 50°C for 30 minutes, and then placed in a flow coater (chamber temperature 80°C).
It was then dried for about 20 minutes. 10 pieces of this dried material
A sieve coated carrier was obtained using a 0 mesh sieve.

This coated carrier 1200I/and prototype toner 90.9
The mixture was stirred for 5 minutes in a V-type mixing bowl to form a starting developer, and then used in a modified copying machine (Sharp iJ SF 770, with the silicone oil application part of the wafer device removed and the temperature of the heating roll made variable). When the image was produced, it had excellent image quality with no fog, and even when continuous copying was performed, more than 10,000 copies could be made. Band 1Jfffl at the beginning of this developer is 18 microcoulombs/9, and 1Jfffl is 18 microcoulombs/9.
Even after 10,000 copies, 4S was confirmed to be an excellent developer in terms of charge amount, with almost no fluctuation of 16 microtrons/g. When the fixability was evaluated by cellophane tape peeling method, it was sufficiently stable at 150°C and no offset phenomenon occurred even at 260°C. Further, when the copy image was sandwiched between soft vinyl chloride files and left in a 169/1an2 cart at 50° C. for one week to evaluate the transferability of the vinyl chloride, no transfer or adhesion of the image was observed.

Comparative Example-1 All except for replacing resin (■) with resin (I) in Example-1 (a toner was produced as a prototype in the same manner, and a copying machine (SF770 modified machine) was produced using the coated carrier with rA bond in Example-1). When I tried to take out the image, there was a lot of background fog (development) and only a blurry image was obtained.
The amounts also showed opposite polarity.

Comparative Example-2 All of Example-1 except for replacing resin ■ with resin ■ (Similarly, a prototype toner was made and the coated carrier manufactured in Example-1 was used for reproduction IQ (SF770 modified machine). When I took out the image, the initial image was 1" clear, but after 5,000 consecutive copies, I noticed that the image had deteriorated. Also, I put it in a vinyl chloride file, and the vinyl chloride migration property. When evaluated, both edges adhered to the soft vinyl chloride file.When the charge amount was jl145d, the initial value was 21μC7.
There was no 3c/gL with 5000 sheets run in g.

Comparison 1 Toso Example-3 Except that P2 used a non-disruptive gear rear iron powder in 5111-14/I '/('!' 4 Example-1 and no times (9
) when I performed the itf value of 'f,lBsuJ +! !
At the stage of 1Ij1r, only a poor curved bow A could be made by 7υ.

Large flow 1χq-2 Polyoxypropylene (2,2) -2,2-His (4
-Hydroxyphenyl) Furopane 3500y1 Inofucle + WIB52g, Anhydrous Trimerit f-mon 576S to Kyo 4? 5 Self-confidence and 4 polynisgur tree t1M (
Resin ■; Softening point: 154°C, Tg: 68°C.

Acid value 24.0 ) 70 parts, styrene 857,! i', 2-ethylhexyl acrylate 120p, dimethylaminoethyl methacrylate 40p
g1 divinylbenzene 6y and azobisdimethylvaleronitrile 20J7 combined and dazzling tree 7iih (4
1 fat 1v; softening point 150°C, Tg 65°C) 25 parts, and pigment glue 15 (1M phthalocyanine, I
L Yukagaku'fJ:,s)sr'+b was kneaded in a ball mill using a Millinob Poso, and crushed into -4:1 color toner (average particle size 13 μm) at 10/ml.

Carrier iron J30UD, 9 is Enzan vinyl vinyl acetate co-dama, a product (weight ratio 80:20, number average molecule pj: 15
,000) 150 & dissolved in 1 shade of toluene! Q4 Seshime 1
This/Δ liquid was added to the solution at a rate of 50" and stirred for 30 minutes, then sprinkled into a flow coke (char/bar internal temperature IM, ao'c) and dried for about 20 minutes. This drying Things 'i 100 horns flili °C sieve 'tJk +2 carriers get lko.

This coated carrier 1200 & prototype blue tiger-90
When i+-F (ltil) was carried out in exactly the same manner as in Example-1 using a starting active agent by mixing G, a clear tone copy without any dirt was obtained, and the storage stability of the vinyl chloride file was also good. When I changed the temperature of the wafer and made electrolytic Y nicks, it was well established at 160°C.Also, I performed coupled α copying, and even after 10,000 copies, I still had a clear image. .Resin 1■ or ', ffJ fat IV was used alone (I made a prototype toner using a blue pigment by the same operation and produced an image using the coated carrier, but I could not obtain a clear image at all. Or, even if it was obtained, the image deteriorated quickly due to continuous shallow shooting (toner scattering around the current hoeing machine was significant).

Comparative Example-4 Carrier iron powder 5ooo & *chlorinated polyethylene 150
9 was added to the molten solution of triene 1AK, sprinkled in a flow coater, and dried for about 20 minutes. Coarse particles were removed using a sieve to obtain a resin-coated carrier. In all cases except for using the coated carrier in Example-1 (similar evaluation was conducted, the image deterioration was rapid in continuous virtual copying (already deteriorated after 10,000 sheets). +L, 1 is 21μc
/i, but after 10,000 copies, it had changed to 8 μall.

Applicant's agent Kaoru Furutani

Claims (1)

[Scope of Claims] 1. In a developer composition comprising a binder resin, a colorant and a carrier, the main components of the binder resin are (Al) a diol component represented by the following general formula (Il) and a divalent or higher polyvalent 10 to 50% by weight of a polyester resin obtained by polymerizing an acid component consisting of a monovalent carboxylic acid, an acid anhydride thereof, or a lower alkyl ester thereof, and a H3 (Bl hydrophobic copolymerizable monomer of 95.0 to 99% by weight). A mixture of 95 parts by weight and all of the 6th class amino group-containing comonomerizable monobonds s, o - o, and o s n represented by the following general formula (6) is polymerized using an azonitrile polymerization initiator. A positively charged electrophotographic developer composition characterized in that the carrier is coated with a vinyl chloride-vinyl acetate copolymer resin. 2. Vinyl chloride- The developer composition according to claim 1, wherein the vinyl acetate copolymer resin is a resin in which J(M) is combined with vinyl chloride at a ratio of 70,598 wt% and vinyl acetate at a ratio of 2 to 60 wt%. Softening point (ASTM
E28-51T) is 100-180℃, resin tB
The developer composition according to claim 1, wherein l has a ring and ball softening point of 100 to 180°C.