JPH01219771A - Binder resin of electrostatic charge image developing toner and production of same - Google Patents

Abstract

PURPOSE:To enhance folding resistance without lowering other characteristics by dissolving a specified polymer produced by solution polymerization in a polymerizable monomer and producing a specified binder resin to be used for a toner by suspension polymerization. CONSTITUTION:The binder resin to be used for the toner enhanced in folding resistance without lowering other characteristics is obtained by producing by solution polymerization the polymer having in the GPC molecular weight distribution a peak in the molecular weight range of 2,000-10,000, a weight average molecular weight to number average molecular weight ratio Mw/Mn of >=3.5, and a glass transition point (Tg) of <=55 deg.C, dissolving the polymer in the polymerizable monomer, and suspension polymerizing them. The obtained polymer has a THF-insoluble fraction in an amount of 10-70wt.%, and in the GPC molecular weight distribution of the THF-soluble fraction a ratio of Mw/Mn of >3.5, a peak in the molecular weight range of 2,000-10,000, and a peak or shoulder in the molecular weight range above this range.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a binder resin for toner used in a dry developer used in electrophotography, electrostatic recording, magnetic recording, etc. Regarding the manufacturing method.

[Prior Art] Conventionally, as an electrophotographic method, U.S. Patent No. 2.297°69
Although many methods are known, such as Japanese Patent Publication No. 42-23'jlO and Japanese Patent Publication No. 43-24748, generally a photoconductive substance is used and a photoreceptor is formed by various means. An electrical latent image is formed on the top, then the latent image is developed using toner, and if necessary, the toner image is transferred to a transfer material such as paper, followed by heating, pressure, heating pressure, solvent vapor, etc. It is used to fix images and obtain copies. Also,
When a process for transferring a toner image is included, a process for removing residual toner is usually provided.

Development methods for visualizing electronic latent images using toner include, for example, the magnetic brush method described in U.S. Pat. No. 2,874,0133, and the magnetic brush method described in U.S. Pat. Cascade development method and 2.221.
The powder cloud method described in US Pat. No. 3,909,258 and the method using conductive magnetic toner are known.

Conventionally, toners used in these development methods are fine powders in which dyes and pigments are dispersed in natural or synthetic resins. Particles obtained by pulverizing the particles to about 1 to 30 particles are used as toner. As the magnetic toner, one containing magnetic particles such as magnetite is used. On the other hand, in the case of a system using a so-called two-component developer, the toner is usually mixed with carrier particles such as glass beads and iron powder.

Today, a copying machine is a typical example of a machine that uses this type of recording method. This machine is surprisingly popular;
It has become indispensable for administrative work. In particular, as images are now widely used in official documents, it has become important to improve the quality of the images. High quality does not just mean good image quality, but also means that it can be maintained for a long time, and even if the copied image is used for a long time and is subjected to harsh conditions such as being folded, the image will not be scratched or scratched. is important.

The ability of this type of toner to firmly adhere to a supporting material such as paper means that it melts at low temperatures and sticks well, so it has the ability to offset, preservability (also called blocking ability) to the fixing roller, and photosensitive properties. This is a fixing ability of a toner that is different from the fixing ability of a toner by the general rubbing method, although it is contradictory to the ability to film on the body, and is becoming important today. However, in order to realize these, there is no point in reducing other performances such as image quality, development characteristics such as toner durability, and toner production efficiency.

These are mainly due to the performance of the binder resin of the toner. Some proposals have been made to improve these by using mold release agents, plasticizers, and other additives, but these are only supplementary.

Various methods have been proposed for improving this binder resin.

For example, Japanese Patent Application Laid-Open No. 56-158340 proposes a toner made of a low molecular weight polymer and a high molecular weight polymer, but although this binder resin has good release properties when bent, it is actually cross-linked. Since it is difficult to incorporate the component, in order to further improve offset resistance, it is necessary to increase the molecular weight of the high molecular weight polymer or increase the ratio. This direction deteriorates the fixing performance and also significantly reduces the crushability, making it difficult to obtain a product that is practically satisfactory.Furthermore, regarding toners blended with low molecular weight polymers and crosslinked polymers, Japanese Unexamined Patent Publication 1983
Japanese Patent No. 88558 proposes a toner containing a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as main resin components. If this method is followed, fixing properties and crushability may be improved, but the weight average molecular weight of the low molecular weight polymer/
The number average molecular weight (Mv/Mn) is as small as 3.5 or less, and the insoluble and infusible high molecular weight polymer is as large as 40 to 90 wt%, so it satisfies high performance in both offset resistance and crushability. In practice, it is extremely difficult to produce toner that fully satisfies fixability, offset resistance, and pulverization properties unless a fixing machine is equipped with an offset prevention liquid supply device. Furthermore, if the amount of insoluble and infusible high molecular weight polymer increases, the melt viscosity will become extremely high during heat kneading during toner production, so it must be heat kneaded at a much higher temperature than usual, or heat kneaded with a high shear. As a result, the former has the problem of deterioration of toner properties due to thermal decomposition of other additives, and the latter has the problem of excessive cutting of binder resin molecules, making it difficult to achieve the original offset resistance performance. .

In particular, this resin contains a large amount of insoluble and infusible high molecular weight polymer, and the 14w/Mn of the low molecular weight polymer to be blended is 3.5.
Since the size is too small, the toner peeling property (hereinafter referred to as bending property) by bending is poor, which causes a serious problem when the copied image is used for a long period of time and is folded.

This improvement in bendability is necessary for copied images to be used as high-quality images on the same level as ordinary printed images.
This is an important point.

Furthermore, JP-A-80-166958 proposes a toner comprising a resin composition obtained by polymerization in the presence of low molecular weight polyα-methylstyrene having a number average molecular weight of 1,500 to 1,500. .

In particular, in this publication, the number average molecular weight (Mn) is s, ooo~
It is said that a range of 30.000 is preferable, but in order to further improve offset resistance, if Mu is increased, fixing performance and pulverization during toner production become practical problems, so high-quality paper does not have offset resistance. It is difficult to satisfy the pulverizability of toner.In this way, toner with poor pulverization properties during toner production not only reduces the production efficiency during toner production, but also has the characteristics of toner that makes it easy for coarse toner to be mixed in. This is not desirable as it may become an image.

Furthermore, JP-A-58-18144 discloses that a binder resin component containing at least one maximum value in each of the molecular weight regions of 103 to 8 x 104 and 105 to 2 x 106 in the molecular weight distribution by GPC is disclosed. toner is suggested. In this case, the toner has excellent crushability, anti-offset properties, fixing properties, filming properties on a photoreceptor, fusion properties, etc., but it is desired to further improve the anti-offset properties and fixing properties of the toner. In particular, it is difficult for this resin to meet today's strict requirements while further improving fixing properties and maintaining or improving various other performances because it does not have a crosslinking component.

[Problems to be Solved by the Invention] As described above, no material has yet been proposed that highly satisfies the necessary items, particularly in terms of other performances and bendability.

An object of the present invention is to provide a binder resin for toner that simultaneously satisfies excellent performance in various aspects and a method for producing the same.

Another object of the present invention is to provide a toner binder resin that has good fixing properties, as well as good offset properties, wrapping properties, and blocking properties, and a method for producing the same.

Another object of the present invention is to provide a toner binder resin with good crushability and high toner production efficiency, and a method for producing the same.

Another object of the present invention is to provide a toner binder resin that has excellent resistance to fusion within an apparatus during pulverization or to a photoreceptor, and a method for producing the same.

Another object of the present invention is to provide a binder resin for toner and a method for producing the same that does not cause problems in developability, particularly image quality, durability, and the like.

Another object of the present invention is to provide a binder resin for toner that has particularly good bendability and a method for producing the same.

[Means for Solving the Problems] The present invention provides a solution in which the insoluble content of tetrahydrofuran (↑HF) is 10
~70% by weight (preferably 10 to 80% by weight), and the molecular weight distribution of the THF soluble portion by GPC is Mw/Mug 3.5, and the molecular weight is 2000~
Tg having at least one peak in the region of 10,000, no peak or shoulder in the region of molecular weight 10,000 or more (excluding 10,000), and a molecular weight of 10,000 or less
, Tg, is 55·C or more. Furthermore, the object of the present invention is to have a molecular weight of 2,
000 to 10.000, and weight average molecular weight/number average molecular weight (Mw/Mn)≦3.5. T
g≧55°C by solution polymerization, dissolving the polymer in a polymerizable monomer, and performing a suspension polymerization reaction in the presence of the polymer to produce the toner binder resin. The present invention relates to a method characterized by:

The configuration of the present invention will be explained.

In order to achieve the above objectives at the same time and particularly to improve bendability, various binder resins were used and their structures and performance were studied from various angles. As a result, it has been found that this can be achieved when the ratio of the THF-insoluble portion of the binder resin and the molecular weight distribution of the THF-soluble portion are in a specific configuration.

When the binder resin is dissolved in a solvent such as THF, it can be separated into an insoluble component and a soluble component, and the molecular weight distribution of the soluble component can be measured by GPC. Focusing on the peaks of the molecular weight distribution of the THF-insoluble and THF-soluble components, the relationship between their positions and crushability is as shown in FIG. From now on, T.H.
A system with no or a small amount of F-insoluble content is disadvantageous in terms of grindability, and as mentioned above, in order to improve grindability, the peak position of the molecular weight distribution of THF-soluble content is simply shifted to a position with a lower molecular weight. This proves that the direction in which the grain size is increased deteriorates offset resistance, making it difficult to satisfy both offset resistance and crushability. From this study, it was found that it is very effective to include a specific amount of THF-insoluble matter not only for the purpose of improving offset resistance, as is generally thought, but also for improving the crushability.

Furthermore, the molecular weight distribution of the THF soluble content, the property of whether the fixable temperature is high or low (hereinafter simply referred to as fixability), offset resistance, pulverization properties, and #blocking properties were investigated. As a result, it was first discovered that, as shown in FIG. 4, for example, the molecular weights below 10,000 and those above about 10,000 behave differently in terms of molecular weight distribution. In other words, the content ratio of components having a molecular weight of 10,000 or less to the entire binder resin does not strongly affect fixing properties or anti-offset properties, as is usually said, but rather has an effect within a specific range. It was found that there was almost no relationship between the two, but instead it was strongly related to the crushability. Furthermore, based on other considerations, the binder resin is
Basically, it has been found that the THF-insoluble content mainly affects offset resistance, coiling properties, and crushability.

In particular, it has been found that the bendability is related to the high molecular weight portion of the crosslinked component cut off by heat kneading or the like. Unlike linear polymer components, this high molecular weight component has many branches and many terminals even with the same molecular weight, so it is thought that it has good adhesion to paper etc. and improves bendability. available.

In addition, the proportion of components with molecular weights to, ooo or less is 10 to
80 wt% is good, preferably 20 to 60 wt%. In order to achieve sufficient performance, the molecular weight io, oo must be further increased.
o or less, 2,000 or more (preferably 2,000 to 8,
000), with a molecular weight of 10,000 (10
2,000 to 10. There is no OOO double peak and there is a peak at a molecular weight of 2,000 or less, or a molecular weight of 1
When the proportion of components having a molecular weight of 0,000 or less is 80 wt% or more, blocking resistance, adhesion to the photoreceptor, filming,
0 molecular weight 1, which causes some problems such as fusion to the inner wall of the crusher
If there is no peak below 0,000 and a peak above to, ooo, or the proportion of the molecular weight of 10,000 or less is 10 wt% or less, the grindability becomes a problem and is necessary. When /Mn is 3.5 or less, the offset resistance tends to decrease, which becomes a problem.

Especially during heat kneading, the crosslinked components are cut and the molecular weight is 50.00.
A peak or shoulder appears below 0, and when the height of the maximum peak is H2, and the height of the peak with a molecular weight of 10,000 or less is Hl, the ratio H1/H2 may be 0.5 to 1O. , is necessary to improve bendability and not deteriorate other properties, and for this purpose, the structure of the resin is required.

When H1/H2 is less than 0.5, problems arise in crushing properties, fixing properties, etc., and when it is greater than 10, problems arise in offset resistance, bending properties, etc.

In addition, when comparing the glass transition point Tgl of the resin with a molecular weight of 10,000 or less in the molecular weight distribution of the THF soluble component and the glass transition point Tgt of the entire resin, if the relationship Tgl ≧Tgt-5 is reached, the fixing property, pulverization properties, adhesion to the photoreceptor, filming properties, and adhesion to the inner wall of the crushing device.

It has been found that blocking resistance and other properties are improved. Here, Tg is preferably 55°C or higher.

Tgl here is measured by the following method. At a temperature of 25°C, THF was flowed at a flow rate of 7 ral per minute, and the concentration of THF-soluble components in the resin composition was approximately 3.
B/ml! Inject approximately 3 ml of THF sample solution into a molecular weight distribution analyzer and separate components with a molecular weight of 10,000 or less.
After fractionation, the solvent is distilled off under reduced pressure, and the components with a molecular weight of 10,000 or less are 20+
The above operation is carried out until approximately sg is obtained, and annealing is performed at 50°C for 48 hours. After this, Tg is measured by differential scanning calorimetry, and this value is designated as Tgl. This measurement is generally known. ASTM 0341B
- It was carried out according to the 82 method.

That is, the temperature was raised to 120 °C or higher by measuring the temperature increase at lO °C / win, held there for about 10 minutes, rapidly cooled to 0 °C, held there for 10 minutes, and then raised at lθ °C / win,
Obtain the endothermic curve. Tg is defined by the intersection of the median line of the baseline and the inflection curve.

As a preparative column, TSKgel G2000H,T
SKgel G2500H, TSKgel G3000H
, TSKgel G4000H (both manufactured by Toyo Soda Kogyo)
etc. are used.

In the present invention, TSKgel G200CIH and TSKge
l G3000H was used in combination.

Further, Tgt, which is 7 g of the resin, is determined by annealing the resin at 50° C. for 48 hours and then using differential scanning calorimetry.

The THF-insoluble content in the present invention refers to the weight percentage of the polymer component (substantially crosslinked polymer) that has become insoluble in THF in the resin composition, and indicates the degree of crosslinking of the resin composition containing the crosslinked component. It can be used as a parameter to indicate. The THF-insoluble content is defined by the value measured as follows.

That is, weigh out 0.5 to 1.0 g of a resin sample (24 mesh passes, 60 mesh powder) (W+g).
, placed in a thimble filter paper (e.g. No. 86R manufactured by Toyo Roshi Co., Ltd.), subjected to a Soxhlet extractor, and added THF 1 as a solvent.
Extract for 6 hours using 00 to 200 Hou rho, evaporate the extracted soluble components with a solvent, vacuum dry at 100 ° C. for several hours, and weigh the amount of THF soluble resin components (
W2g), IF insoluble content of the resin is calculated from the following formula.

In the present invention, the molecular weight of the peak and/or shoulder of a chromatogram by GPG (gel permeation chromatography) is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40°C, and THF was added to the column at this temperature as a solvent.
(Tetrahydrofuran) at 11 f/min! Measurement is performed by injecting 50 to 200 times of a THF sample solution of the resin adjusted to a sample concentration of 0.05 to 0.6% by weight. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithm value and the count number of a calibration curve prepared using several types of monodisperse polystyrene standard samples. As a standard polystyrene sample for creating a calibration curve,
For example, Pressure Chemical Co.
or manufactured by Toyo Tsudani Gyo Co., Ltd. with a molecular weight of 6X102.
2. lX103. 4X103゜1.75X 104,
5. IX 104.1. IX 105.3.9X 1
05゜8.8 x 105.2 x 106.4.48
It is appropriate to use at least 10 standard polystyrene samples. Further, an R1 (refractive index) detector is used as a detector.

In addition, in order to accurately measure the molecular weight area of 103 to 4 x 106 as a column, it is recommended to combine multiple reprinted polystyrene gel columns.
p-styragel 500.103.1 manufactured by rs
0', 105 combination, 5bod manufactured by Showa Denko
ex KF-80%, KF-801, 803, 804
, 805 combination, KA-802.

803, 804.805 combination, or TSKgel G100OH, G2000H, G manufactured by Toyo Soda
2500H, G3000H.

G4000H, G5000H, Ge0OOH, G100
OH, GIIIH (7) combination is preferred.

The weight percent of the binder resin of the present invention having a molecular weight of 10,000 or less is 100% by weight in the chromatogram determined by GPC.
00 or less, calculate the weight ratio with the cut pieces having a molecular weight of 10,000 or more, and use the weight % of the THF-insoluble content described above to calculate the weight % with respect to the entire binder resin.

As the constituent components of the resin of the present invention, various materials that are generally used as toner resins can be used as long as they can achieve the above-mentioned molecular weight distribution, but among them, vinyl monomers are used. Vinyl polymers, vinyl copolymers, and compositions of these polymers and copolymers were preferred.

Examples of the vinyl monomers (monomers) applicable to the present invention include styrene, α-methylstyrene, P-crossstyrene, and its substituted acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, Monocarboxylic acids having double bonds or substituted products thereof such as dodecyl acrylate, octyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. ;
For example, dicarboxylic acids with double bonds such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate, etc.; and substituted products thereof; triesters, such as vinyl chloride, vinyl acetate, vinyl benzoate, etc.; e.g. Vinyl monomers such as vinyl ketones such as vinyl methyl ketone, vinyl exyl ketone, etc.; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. may be used alone or in combination of two or more. Among these, a combination of a styrene polymer and a styrenic copolymer is preferred.

The selection of the initiator, type of solvent, and reaction conditions when producing the resin of the present invention are important factors in obtaining the resin targeted by the present invention. Examples of initiators include benzoyl peroxide, l,1-di(t-butylperoxy)-3,3
, 5-trimethylcyclohexane, n-butyl-4,4
-di(t-butylperoxy)valerate, dicumyl peroxide, α,α′-bis(t-butylperoxydiisoprobyl)benzene, t-butylperoxycumene, di-t-butylperoxide, etc. Organic peroxides, azo and diazo compounds such as azobisisobutyronitrile, diazoaminoazobenzene, etc. can be used.

As the crosslinkable monomer, compounds having two or more polymerizable double bonds are mainly used. Examples: Aromatic divinyl compounds such as EVA, divinylbenzene, and divinylnaphthalene; For example, carboxylic acid esters with two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, and divinyl Divinyl compounds such as aniline, divinyl ether, divinyl sulfide, divinyl sulfone and compounds having three or more vinyl groups are used alone or as a mixture. Among them, divinylbenzene is effective.

Further, although the resin of the present invention exhibits a glass transition point that varies considerably depending on the type and composition of monomers contained as components, a glass transition point in the range of 40 to 80°C is effective. More preferably, the glass transition point is 50 to 6.
5°C is preferable from the viewpoint of blocking resistance and fixing properties. If the glass transition point is lower than 40°C, thermal agglomeration caking is very likely to occur during toner storage, and aggregation troubles may occur in copying machines. It becomes easier to do. On the other hand, if the glass transition point exceeds 80° C., the heat fixing efficiency will deteriorate.

In the method for producing the binder resin of the present invention, the first resin is produced by solution polymerization, the first resin is dissolved in a polymerizable monomer, and the polymerizable monomer is dissolved in the presence of the resin and a crosslinking agent. Suspension polymerization of monomers is carried out. Monomer 100 for suspension polymerization
It is preferable that 10 to 150 parts by weight of the first resin be dissolved in the suspension polymerization. 2. Owt%
These conditions which are preferably used depend on the type of initiator,
Some variation is allowed depending on the reaction temperature.

A case in which the first polymer is dissolved in a monomer and subjected to suspension polymerization to obtain the binder resin, a polymer obtained by suspension polymerization without dissolving the first polymer, and a case in which the first polymer is obtained by suspension polymerization without dissolving the first polymer. It has been found that this is different from a blend polymer that is simply mixed together.

The former is that in the GPC chromatogram of the THF-soluble content, the high molecular weight content is slightly larger than the latter. This is because the dissolved first polymer influences the suspension polymerization, which has an effect that exceeds the advantage of uniformly mixing the polymers.

Solution polymerization and suspended FiJ polymerization according to the present invention will be described below.

Solvents used in solution polymerization include xylene, toluene,
Cumene, cellosolve acetate, isopropyl alcohol, benzene, etc. are used. In the case of the styrene monomer, xylene, toluene or cumene is appropriately selected depending on the desired polymer to be produced by zero polymerization. Further, the initiator includes di-tert-butyl peroxide, tert-butyl peroxybenzoate, benzoyl peroxide, 2.
2'-7zobisisobutyronitrile, 2,2'-azobis(2,4dimethylvaleronitrile), etc. are monomers 10
0.1 parts by weight or more (preferably 0.4 parts by weight)
The reaction temperature used at a concentration of 15 parts by weight) varies depending on the solvent, initiator, and polymer to be polymerized, but is preferably 70°C to 180°C. On the other hand, it is preferable to use 30 to 400 parts by weight of 7-mer.

Suspension polymerization is preferably carried out using 100 parts by weight or less (preferably 10 to 80 parts by weight) of monomer per 100 parts by weight of the aqueous solvent. Dispersants that can be used include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, etc., and there is an appropriate amount depending on the amount of monomer relative to the aqueous solvent, but in general, 100% of the aqueous solvent is used.
It is used in an amount of 0.05 to 1 part by weight. The polymerization temperature is suitably 50 to 95°C, but should be appropriately selected depending on the initiator used and the intended polymer. Any initiator can be used as long as it is insoluble or poorly soluble in water; for example, benzoyl peroxide, tart-butyl peroxyhexanoate, etc. 0.5-10 for
Used in parts by weight.

In addition to the above-mentioned binder resin component, the toner using the resin of the present invention may contain the following compounds in a proportion smaller than the content of the binder resin component, within a range that does not adversely affect the effects of the present invention. You can.

For example, silicone resins, polyesters, polyurethanes, polyamides, epoxy resins, polyvinyl butyral, rosins, modified rosins, terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins such as low molecular weight polyethylene or low molecular weight polypropylene, aromatic These include family petroleum resins, chlorinated paraffin, and paraffin wax.

When preparing a magnetic toner using the binder resin of the present invention, magnetic fine particles are contained in the toner. The magnetic fine particles may be any material that exhibits magnetism or can be magnetized, such as metals such as iron, manganese, nickel, cobalt, and chromium, magnetite, hematite, various ferrites, manganese alloys, and other ferromagnetic alloys. These are used for average particle diameters of 0.05 to 5 (more preferably 0.1 to 1).
) can be used as a fine powder. The amount of magnetic fine particles contained in the magnetic toner is 15 to 7 of the total weight of the toner.
0% by weight is good.

Furthermore, various substances can be added to the toner according to the present invention for the purpose of coloring, controlling charge, etc.

Examples include carbon black, iron black, graphite, nigrosine, metal complexes of monoazo dyes, ultramarine blue, phthalocyanine blue, visor yellow, benzidine yellow, quinacridone, and various lake pigments.

The toner made from the above-mentioned binder resin, magnetic fine particles, colorant, charge control agent, etc. has strong resistance to the load applied in the developing device, and was not crushed and deteriorated in the durability test.

As a fixing aid, an ethylene-based olefin polymer may be used together with a binder resin.

Examples of the ethylene olefin monopolymer or ethylene olefin copolymer used here include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyethylene There are ionomers having a skeleton, and the above-mentioned copolymers preferably contain 50 mol% or more (more preferably 60 mol% or more) of olefin monomers.

Next, an electrophotographic method using a developer using a resin according to the present invention will be explained.

The process of developing the electrical latent image with toner includes the aforementioned magnetic brush method, cascade development method, powder cloud method, and U.S. Patent Section 3. There are a method using a conductive magnetic toner described in SO8,258, a method using a high-resistance magnetic toner described in JP-A-53-31138, etc.Resins according to the present invention The developer using the above is also suitable for a development method using a so-called -component type developer containing magnetic fine particles. In the process of transferring the developed image to the transfer target member, an electrostatic transfer method such as a corona transfer method or a bias transfer method is used.

Furthermore, in the toner using the binder resin of the present invention, a blade cleaning method, a fur brush cleaning method, etc. are applied to the step of removing residual toner on the photosensitive layer or insulating layer, but the blade cleaning method is particularly applicable. Are suitable.

In addition, the powder image on the transferred member needs to be fixed on the member, and methods for this purpose include a heat fixing method, a solvent fixing method, a flash fixing method, a laminate fixing method, etc. Suitable for roller fixing method.

[Example] Parts in the following examples mean parts by weight.

Example 1 200 parts of cumene was placed in a reactor and heated to i-stream temperature. To this was added 100 parts of styrene monomer and
A mixture of 6.5 parts of butyl peroxide was added dropwise over 4 hours under cumene reflux. Zaraani cumene under reflux (146
The polymerization was completed at 158°C) and the cumene was removed.

The obtained polystyrene was dissolved in THF and Mv=5,1
00, My/Mn = 2.80, cpc The molecular weight at which the main beak is located is 5.000, Tg = 82°C
Met.

Dissolve 30 parts of the above polystyrene in the following monomer mixture,
A mixed solution was prepared.

Add 0 partially saponified polyvinyl alcohol to the above mixed solution.
．． 170 parts of water in which 1 part was dissolved was added to form a suspension dispersion. The above dispersion was added to a reactor containing 15 parts of water and purged with nitrogen, and subjected to suspension polymerization reaction at a reaction temperature of 70 to 85° C. for 6 hours. After completion of the reaction, it was separated and dehydrated.

It was dried to obtain a composition of polystyrene and styrene-n-butyl acrylate copolymer. In the composition, THF-insoluble and THF-soluble components were uniformly mixed, and polystyrene and styrene-n-butyl acrylate copolymer were uniformly mixed. The THF-insoluble content of the obtained resin composition (2
(using a resin composition powder of 4 mesh passes and 60 mesh ions) was 55 wt%. In addition, when the molecular weight distribution of the THF-soluble component was measured, there was a peak at the position of 0.51 million, Mn = comb l-0 0.38 million, Mw = 15,000, Mw/Mn =! ＃'
*, molecular weight of 10,000 or less was 24vt%. Furthermore, the Tg of the resin was 65°C, and 1
The glass transition point rg+ of the component of 1,000 or less was 62°C.

A GPC chromatogram of the THF-soluble fraction is shown in FIG.

In addition, the characteristics related to the molecular weight of each resin and resin composition were measured by the following method.

5hodex K F-8 as cpc g regular column
0M using a GPC measurement device (Waters 150
CAIG:/GPC) was installed in a 40°C heat chamber at a THF flow rate of 1 if/sin, and the detector was injected with 200 ILi' of a sample (concentration of 0.1% by weight of THF soluble content) under RI conditions. GPC was measured. The calibration curve for molecular weight measurement is molecular weight 0.5 x 103.2.
35 X103.10.2 X103゜35X 103
, ll0X 103 , 200X 103 , 47
0X 103. +200X103, 2700X10
A THF solution of a 10-point monodisperse polystyrene reference material (manufactured by Waters) measuring 3.8420 x 103 was used.

Example 2 200 parts of cumene was placed in a reactor and the temperature was raised to reflux temperature. The following mixture was added dropwise to the cumene over 4 hours under reflux.

Further, the polymerization was completed under cumene reflux (146-156°C) to remove cumene. The obtained styrene polymer has Mw
= 4,500, 14w/Mn = 2.9, the main peak was at the molecular weight position of 4,500 in the GPC chart, and Tg = 80°C.

Fifty parts of the above styrene polymer was dissolved in the following monomer mixture to form a mixed solution.

Add 0 partially saponified polyvinyl alcohol to the above mixed solution.
．． 170 parts of water in which 0.09 parts was dissolved was added to form a suspension dispersion. The above dispersion was added to a reactor containing 15 parts of water and purged with nitrogen, and reacted at a reaction temperature of 70 to 95°C for 6 hours.

After the reaction was completed, the mixture was separated in a furnace, dehydrated, and dried to obtain a composition of a styrene polymer and a styrene-2-ethylhexyl acrylate copolymer.

The THF-insoluble content of this composition was 18 wt%.

Furthermore, when the molecular weight distribution of the THF-soluble component was measured, there was a peak at the molecular weight position of 0.47 million, and Mn = 0.34 million.

Mw=24,000, Mw/Mn=7.06. The molecular weight of 10,000 or less was 48 wt%. Further, the Tg of the resin was 60°C, and the glass transition point Tg of the components of 10,000 or less separated by GPC was 80°C. This GPC
The chromatogram of the soluble content is shown in Figure 2.

Production Example 1 Toner was prepared in the following proportions based on 100 parts of the resin of Example 1.

It is created by the commonly used processes of hot kneading and pulverization. The resulting toner had a particle size of about 11.5 g. At this time, the GPC of the THF-soluble portion of the toner showed a peak at about 2,000,000, which was due to the crosslinking component being cut. Moreover, H+/H2 was about 2. The crushability was good, and there was no fusion within the crusher. Also,
Even in a blocking test by leaving it at 50°C for one day, it was at a level that caused no practical problems.

An image test and a fixing test were performed on this using a Canon copier, NP-7550, and the results were good with no problems.

A full black image was produced using this copying machine, and a bendability test was conducted.

As a result, the reflected image density of the folded image of 1.4 was 1.35, and the reduction rate was +3.8%, which was very good. By the way, the reduction rate is +10%, which is at a good level, so it can be said to be particularly good.

The method for evaluating bendability is as follows.

To evaluate the bendability, a black image was created on the entire surface, the image surfaces were folded overlapping each other, and rubbed back and forth 10 times with a load of approximately 200 g.
The image of the folded part is drawn back and forth 10 times on Silbon paper C for about 20 minutes.
Reflection density reduction rate (%) of peeling of rubbed image under 0g load
).

Production Example 2 A toner was produced in the same manner as Production Example 1 using the resin of Example 2. At this time, the molecular weight of the THF soluble portion of the toner was determined to be 6 by GPC.
A peak appeared at 00,000, and H1/H2 was about 4. The crushability and all other performances were at a good level.

The bendability was very good, with an image with a reflection image density of 1.35 having a decrease of +3.7%.

[Effects of the Invention] By using the toner binder resin of the present invention, a toner with good fixing properties, offset properties, wrapping properties, blocking properties, etc. can be obtained.

Further, a toner with good crushability and production efficiency can be obtained. In particular, a toner with good bendability can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows a GPC chart of the THF-soluble content of the resin composition prepared in Example 1 and FIG. 2 in Example 2. FIG. 3 is a graph showing the relationship between the content of THF-insoluble matter and crushability, and FIG. 4 is a graph showing the correlation between the content of components with a molecular weight of 10,000 or less and toner properties. It is.

Claims (2)

[Claims] (1) In a toner binder resin having a THF-insoluble content and a THF-soluble content, the THF-insoluble content is contained in an amount of 10 to 70 wt%, and the molecular weight distribution of the THF-soluble content by GPC is Mw/Mn>3.5. Yes, molecular weight 2,000-1
A binder resin for a toner, which has at least one peak in a molecular weight region of 0,000 and no peak or shoulder in a molecular weight region exceeding 10,000. (2) In the molecular weight distribution of GPC, the molecular weight is 2,000
~10,000, and Mw/Mn
≦3.5, Tg≧55°C is produced by solution polymerization, and the polymer is dissolved in a polymerizable monomer and subjected to suspension polymerization to obtain a THF-insoluble material containing 10 to 70% by weight of THF-insoluble matter. In the molecular weight distribution of the dissolved component by GPC, Mw/Mn>
3.5, has at least one peak in the molecular weight region of 2,000 to 10,000, has no peak or shoulder in the molecular weight region exceeding 10,000, and has a molecular weight of 10.
,000 or less components are 10 to 60 based on the entire resin
A method for producing a binder resin, characterized in that the binder resin contains % by weight.