JPS59128557A - Powdered developer used for laser printer - Google Patents

Abstract

PURPOSE:To prevent filming of a toner by incorporating an epoxy type toner in carrier particles coated with a butadiene polymer. CONSTITUTION:A magnetic brush developer for use in a laser printer is obtained by coating a carrier base of iron particles with a butadiene polymer contg. dispersed Fe3O4 powder as a charge controller to form carrier particles having electric conductivity near to conductors, and mixing 1-6wt% toner particles (based on the carrier) made of an epoxy resin contg. a styrene-n-butyl acrylate resin. A suitable epoxy resin for a chief component of the toner is an epichlorohydrin type resin contg. <=4wt% bisphenol A glycidyl ether of 0 polymn. degree, and having 60-160 deg.C and 1,000-10,000 weight average mol.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to a magnetic brush developer for laser printers employing electrophotography.

(2) Background of the Invention The magnetic brush development method has been applied to copying machines, facsimile machines, electronic printers, and the like. Particular features of this method include: 1) It is a dry system, 2) In principle, there is no choice of paper quality, and 3) High-speed printing is possible. These features have become even more important in laser printers.

As output information from computers becomes more diverse, printers must be able to respond to these diversifications, and in particular, it has been desired to output in kanji in addition to the conventional alphanumeric characters. In response to this need, laser printers have appeared, but since laser printers print entirely using laser light, and the spot diameter of the laser light is approximately 100 to 150 μm, the resolution of kanji, etc. It can be said that it is optimal for printing with

(3) Prior Art and Problems Laser printers have many excellent functions as described above, but in order to fully utilize all of these functions, the performance of the developer must be high. That is, depending on the performance of the developer, the characteristics of the laser printer cannot be fully demonstrated.

What kind of performance is required of a developer used in a laser printer? That is, it is to exhibit stable printing performance over a long period of time. A magnetic brush developer is a mixture of iron powder or other ferromagnetic particles and colored resin powder. That is, the toner electrostatically adheres to the surface of the carrier due to contact frictional charging during mixing. The developer is transferred to the latent image area by the formation of a magnetic brush,
Development is performed by only toner adhering to the latent image (FIG. 1).

As shown in FIG. 1, the developer is stirred in the developing machine, and a mechanical shock is applied to the developer due to this stirring. Therefore, the resin-based toner becomes fused to the carrier surface. The generation of fused toner (hereinafter referred to as spent toner) makes the carrier surface homogeneous with the toner, and contact triboelectric charging is greatly inhibited.

The generation of spent toner stops the function of the developer, and in actual developers, it is necessary to make it difficult for both the carrier and the toner to stick to each other.

In the development process using a developing machine, the toner that has received the band t is constantly moving to the latent image, and it is necessary to replenish the developer with an amount of uncharged toner corresponding to this (see Figure 1).
As a result, a counter charge of the toner constantly accumulates in the carrier, and as the charge approaches the saturation value, the ability to impart a charge to the toner, that is, the charging property, decreases.

However, in order to prevent the deterioration of chargeability due to charge-up, it is necessary to lower the resistance of the carrier and developer. However, there is a relationship between the chargeability of the developer and the resistivity of the carrier as shown in FIG. 2, and lowering the resistance more than necessary is undesirable because it causes a decrease in chargeability.

On the other hand, the resistivity of the developer plays a very large role in printing. When toner adheres to the latent image, there is a phenomenon in which the toner is difficult to adhere to the central part of the image a, where the density of electric lines of force is low.

As a result, when printing a surface image having a certain area, toner adheres only to the peripheral portion, and the central portion is left blank, resulting in one printing defect. As a method for eliminating such inconveniences, there is a method of controlling printing by applying a bias field.

A bias electric field is an electrostatic field applied between a magnetic brush and a latent image, and this electric field can separate the toner from the carrier and transport and adhere the toner even to areas with low electric flux density.

Therefore, by appropriately setting the bias electric field, it is possible to control the print density, thicken or thin the print, and further control the area printing. However, if the electrical resistivity of the developer, especially the carrier, is high, the voltage drop at the magnetic brush portion will be large, and no effective electric field will act between the tip of the magnetic brush and the latent image surface (FIG. 3).

Therefore, the resistivity of the carrier must be low to some extent. However, if the resistance of the carrier is too low, the carrier becomes electrically conductive, causing not only the charge of the latent image to disappear and the toner to adhere to it, but also a discharge due to the bias electric field to occur as shown in Figure 3, causing the latent image to become cause damage. Furthermore, if a bias electric field is not applied, problems such as severe fogging may occur due to the self-bias caused by the developing current that causes the toner to move toward the latent image. Therefore, it is thought that there is an optimal range for carrier resistivity.

In a developer composed of a carrier and a toner, a factor that influences printing characteristics is the amount of charge per unit weight of toner (hereinafter referred to as tp). It is not preferable that tp is too low or too high, and 10 to 2011G is appropriate. There are several factors that affect the tp value in a developer, but the surface condition of the carrier is considered to be particularly important.The degree of curing of polybutadiene in the coating layer has a large effect on the tp value. Therefore, when the amount of curing agent is small, that is, when the degree of curing is low, tp is not stable and decreases as printing progresses.Also, as the amount of curing agent increases, the coating layer rapidly hardens and shrinks, causing cracks to occur. A hard coating layer is not formed.There is an optimum amount of curing agent to be mixed.

The surface of the carrier is made non-adhesive by forming a Teflon film on its surface. However, the Teflon film has disadvantages such as high electrical resistivity, brittle coating layer, and high quenching temperature (300° C. or higher).

Generally, dispersing carbon is considered to reduce the resistance of the coating layer, but it is difficult to uniformly disperse carbon in the coating resin, and carbon particles come off from the coating layer while stirring the developer. I end up.

The toner is mainly composed of colored resin powder, and is triboelectrically charged when it comes into contact with the carrier.The toner is then carried by the carrier to the latent image area, subjected to development, and then transferred to paper and fixed, completing the printing process. do. Here, fixing refers to a process in which the image transferred to the paper is a powder image, and this is brought into close contact with the paper. Fixing methods include 1) open fixing and 2) pressure fixing.

There are 3] thermothermocompression bonding, 4) fludge fixing, 5] solvent fixing, etc., but 1) to 4) can be said to be the main ones. These fuse the toner to the paper using heat, pressure, or the like. Therefore, if fixing is attempted with less energy, a resin with a low melting point will be used as the base material, which will cause the following problems. On the other hand, in order to avoid this problem, there is a tendency to raise the melting point of the resin, which causes poor fixing. The above-mentioned problems are as follows. 1) toner fusion to the carrier and 2) toner fusion to the photoconductor drum, both of which significantly reduce the printing function and sometimes cause the printing function to be lost.

Since the developer is stirred in the developing machine, a mechanical impact force acts between the toner and the carrier.

Therefore, the resin-based toner is softened by this impact and fused to the carrier surface. As a result, it exhibits the same effect as coating the carrier surface with toner,
If the toner is sufficiently charged, it will disappear. For this reason, as mentioned above, the surface of the carrier is coated with a resin that is non-adhesive to the toner.
In order to further prevent adhesion, it is necessary to make the toner itself less likely to stick.

Even after the transfer to paper is completed, a considerable amount of toner remains on the photocon drum. This residual toner will cause problems in the next printing process, so a far brush (Far brush) is used.
h) l/1: thus removed. At this time, the toner particles are struck onto the photocon surface by the fibers forming the brush and are fused to the photocon surface. The fusion of toner on the surface of the photocon not only reduces the photosensitivity of the photocon, but also causes afterimages on prints. In order to overcome these disadvantages, it is necessary to make the l-ner particles non-adhesive, and this method is especially effective when it is difficult to make the surface itself non-adhesive, such as on the surface of a photocon. It is. Therefore, in order to prevent the toner from adhering to the carrier and photocon, it is necessary to prevent the toner from adhesion without increasing the melting point.

(4) Purpose of the Invention An object of the present invention is to provide a carrier having excellent mechanical strength, low heat treatment temperature, excellent non-adhesiveness to toner, and a coating layer with relatively low electrical resistivity; It is an object of the present invention to provide a magnetic brush developer for a laser printer comprising a toner having excellent non-adhesion to a condo drum.

(5) Structure of the Invention The above-mentioned object of the present invention is to coat carrier particles with iron powder as a carrier base material with a butadiene polymer in which Fe3O4 powder is dispersed, and to coat carrier particles with epoxy resin as a main component and styrene-
Toner particles containing loop tyl acrylate resin,
1 to 6 weight ratios mixed for carrier weight ff
, can be achieved by a magnetic brush developer for laser printers.

Fe s 04 powder i”i-coating is easily dispersed in the resin phenol and exhibits conductivity close to that of a conductor,
Furthermore, it is a charge control agent. Therefore, by dispersing Fe504 powder in a coating resin and coating it, it is possible to achieve both low resistance in the carrier and non-adhesion to toner. In addition, the resistivity of the base material iron powder is also involved in reducing the resistance of the carrier, and if the base material itself has high resistance, it cannot be expected to significantly lower the resistance through coating treatment. Figure 4 shows the same coating (coating thickness 1.0
Weight ratio of μm butadiene polymer/Fe B 04 = 1
4) is shown. Next, regarding the case where coach ink was applied to iron powder showing a resistivity of 100 m or less, butadiene polymer/Fe, O
, and the change in resistivity with respect to this is shown in FIG. 5A. As a result, the resistivity is almost constant when Rv≦2, but increases rapidly when Rv>2. From this, Rv≦2 is preferable in terms of manufacturing stability, that is, less fluctuation in resistivity. As shown in FIG. 5B, the charge imparting ability of the carrier to the toner is 1 when Rv≦2.
Although it is almost stable between 0 and 20 μC/7, it increases rapidly when Rv>2. The relationship with these volume ratios shows the same tendency when the particle size of the iron powder is 80 μm (a) and when it is 140 μm (b).

The volume ratio Rv of butadiene polymer/Fe3O4 is IA
~2/l, more preferably 1/4 to 1/1.

- When this ratio is smaller than 1/8, the amount of binder resin to Fe3O4 is small, and the coating layer becomes brittle.
Fe3O4 particles come off from the coating layer during printing. On the other hand, if it is thicker than 2/1, the electrical resistivity of the carrier increases as described above, making it impossible to achieve the intended purpose.

Butadiene weight to coat carrier iron powder is 10
,000 to 200,000,'! ! : or acrylonitrile copolymer cyclized products are preferred. Preferably, this polymer is coated with an organic peroxide and then heat-treated to cure the polymer.

The non-adhesive property that it has is lost.

The number average molecular weight of polybutadiene is 10. If it is smaller than OOO, the resin before curing is semi-solid or liquid, so
When forming a coating layer, carriers can easily meet each other. If it is thicker than 200,000, it becomes difficult to dissolve in the solvent, and the resin solution concentration for performing the desired coating cannot be obtained.

Styrene grass containing 1.4-cis polybutadiene 1.4
- The inherent non-adhesive property of cis-polybutadiene is lost.

The average particle size of the carrier iron powder is preferably 50 to 500 μm. If the particle size is smaller than 50 μm, the carrier will adhere to the latent image along with the toner, resulting in a decline in print quality.If the particle size is larger than 500 μm, it will be difficult to print fine patterns, such as Chinese characters that require high resolution. , sufficient printing becomes impossible.

Fe3O4 dispersed in the resin of the carrier coating layer
The average particle size of the powder is 0.1-1. Otim, 0 more
．． 1 to 0.5 μm is preferable. If the average particle size is smaller than 0.1 μm, the particles tend to aggregate more strongly, making it difficult to uniformly disperse them in the coating layer. If it is larger than 1.0 μm, the F+404 particles will stick out from the coating layer, and the collision between the carrier particles will cause
Particles may come off.

The thickness of the carrier coating layer is preferably 0.1 to 10 μm, more preferably 0.5 to 1.5 μm. If it is smaller than 0.1 μm, it will be difficult to uniformly disperse the Fe3O4 particles and the non-adhesive effect will be diminished. If it is thicker than 10 μm, the electrical resistance of the coating layer increases and the intended purpose cannot be achieved.

The peroxide added to the carrier coating polymer is preferably 0.5 to 5.0 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the polymer. If the amount is less than 0.5 parts by weight, the coating layer will be insufficiently cured and will not exhibit sufficient chargeability. If it is thicker than 5% by weight, the charge imparting ability to the toner becomes excessive, making it necessary to print with a high toner concentration, resulting in a decrease in printing quality.

If the mixing ratio of toner particles to carrier is less than 1% by weight, sufficient printing density cannot be obtained, and conversely, if it is more than 6% by weight, toner particles cannot come into contact with the surface of the carrier, resulting in the generation of uncharged toner. This results in a decrease in print quality.

Epoxy resin, which is the main component of toner, has a melting point of 60 to 16
A bisphenol A/epichlorohydrin type embossed resin having a weight average molecular weight of about 1,000 to 10,000 at 0°C, and a bisphenol A glycidyl ether content of 4% by weight or less with a degree of polymerization of 0 is preferred. If the melting point of this epoxy resin is lower than 60°C, it is undesirable because when used as a toner, particles tend to adhere to each other and cause blocking.
If the temperature is higher than 60° C., poor fixing to paper occurs. If the weight average molecular weight is less than 1000, the melting point will be lower than 60°C, and if it is larger than 10,000, it will be higher than 160°C, causing the same disadvantages as in the above case.

Styrene-lubuter acrylate, which is used in common with epoxy resin, mainly has the function of increasing the melt viscosity of the toner and preventing the agglomeration of the molten toner, thereby preventing the generation of voids in the fixed toner image. Due to its non-adhesive properties, it also has the ability to improve the filming resistance on drums. Stine-7L-acrylate resin has a softening point lower than 100°C and a molecular weight of 1
If it is less than 0,000, it is insufficient to prevent the generation of voids, the softening point is higher than 150°C, and the molecular weight is 100.0.
If it is thicker than 00, it is undesirable because it deteriorates the fixing layer. The toner containing this styrene-ruacrylate has the advantage of being widely applicable to heat fixing, heat pressure fixing, Franche fixing, and the like. The epoxy resin content of the toner is the amount of carbon, dye, and styrene-looptyl acrylate subtracted from the toner weight. It is appropriate that the carbon content of the toner is within 8M. Although carbon is used as a colorant, it does not necessarily have to be included, but if it exceeds 8% by weight, the softening point and melting point of the toner will rise, and the fixing properties will deteriorate. Further, the dye is necessary as a charge control agent, and an appropriate amount of the dye is 5% by weight or less. That is, if it exceeds 5% by weight, the conductivity of the toner will improve and the charging property will decrease.

The average particle size of the toner is 5 to 30 μm and 5 to 25 μm.
is preferred. If the particle diameter is smaller than 5 μm, the fine toner particles have a high specific charge C (charge amount per unit weight), so they preferentially adhere to the carrier surface and prevent the necessary charging of the toner particles. If it is thicker than 25 μm, on the contrary, the specific charge becomes small, so that the amount of charge is insufficient and sufficient printing quality cannot be obtained.

(6) Examples and Comparative Examples [Example 1] Irregular spherical TS-20OR (8 iron powder, average particle size 80 μm) was used as the base iron powder, and 1.2-polyptadiene:/RB-810 ( Japan Synthetic Rubber), EPT-500 (Toda Kogyo, particle size 0.1-0.3 as Fe3O4 powder)
ttm) was used. Polybutadiene 25 F, Fe
504 powder 1007, trichlene 1 t, dicumyl peroxide (NOF, Berksil D) 0.25 P as an organic peroxide, and 50 15 x φ steel balls were placed in a polyethylene wide-mouth bottle and rotated on a ball mill stand for about 1 hour. (150 rpm) L, a polybutadiene varnish was prepared, and Fe sO<particles were dispersed in the varnish. Next, after the stirring was completed, 5kp of base iron powder was added to the wide mouth bottle, and while stirring (100 rpm),
Trichlorene vapor generated inside the container was removed by a pump.

This process was continued for about 5 hours, and the predetermined trichlene was almost completely removed, the iron powder became smoother, and about 1 μm thick was added to the surface of the particles.
A uniform coating layer of m was formed. Next, put the coated carrier into a rotary furnace and heat it to 180°C.
After the heat treatment was completed, the samples were classified using a #100 sieve, and those that passed through the sieve were collected as non-defective products.

Next, the epoxy equivalent is 1130, the weight average molecular weight is 2000
, and a bisphenol A/epichlorohydrin type epoxy resin having a melting point of 110° C. and further containing about 3% by weight of bisphenol A glycidyl ether with a degree of polymerization of O (Evicron EXA-1191, Dainippon Ink Chemical Construction).
and styrene-looptyl acrylate resin (Hymer SBM-
600, Sanyo Kasei), carbon (Black Bars L1 Cabonoto Co., Ltd.) as a coloring agent, and Glossin Base EX (Orient Chemical) as a dye, were kneaded for 1 hour in a heated pressure kneader at the composition ratio shown in Table 1, and then kneaded for 1 hour. The toner was pulverized by a jet bulbilizer and classified by a wind classifier to produce four types of toner.

Table 1 Toner composition Developer consisting of the above toner and carrier (toner concentration 3
% by weight) and F-6715D laser printer.
(Fujitsu) was used to conduct a printing test. As a result, ■
It was found from the microscopic photographs that the occurrence of voids was reduced for each toner marked ◎■, and the fixed image was a dense fused toner. In addition, these toners have significantly reduced adhesion to the photocon drum, but their fixing properties are conversely reduced.

Next, prepare a developer (toner concentration 2.5% by weight) from the above carrier and toner ◎, and use the F-6700D printer (
A printing test was conducted by Fujitsu. Furthermore, F-6700
The performance of the D printer is shown in Table 2.

Table 2 Specifications of F-6700D As a result, high-resolution images of lz 1ine/min are obtained, and at the same time, the initial optical density, charge amount, print quality, and surface print characteristics are maintained up to 1.1 million sheets. At the same time, the fusion of the toner to the carrier was stable at 0.6% by weight or less (FIG. 6). Furthermore, it was possible to print up to 2 million sheets, and the amount of fused toner after 2 million sheets was approximately 1.0% by weight, but the initial value was maintained except for a slight decrease in surface printing characteristics. was. In printing with this developer, image control by applying a bias electric field was easy, and full area printing was also possible. On the other hand, almost no toner adhesion to the photocon drum was observed up to 20,000 sheets, and the intended purpose was achieved.

(Comparative Example 1) The toner was the same as in Example 1. The carrier was the same as in Example 1, except that Ffl s 04 powder was not dispersed in the coating layer and only 1,2-polybutadiene was used.

In this case, assuming a toner concentration of 4% by weight, F'-670
When we conducted a similar experiment with 0DK, we found that the amount of toner band started to decrease after 20,000 sheets, and 2
In the case of 00,000 sheets, the toner was scattered from the carrier surface, and the print amount decreased significantly.

Note that this carrier had a resistivity of 100α or more, and printing with bias was impossible (the Fe3O of the carrier
4. Effects of non-addition).

(Comparative Example 2) A developer with a toner concentration of 4% by weight was prepared using the carrier described in Example 1 and the toner described in Example 1, and a printing test was conducted using F-6700D. As a result, filming occurred on the drum after 4,000 sheets, and at 10,000 sheets, an offset phenomenon occurred in which the toner fused onto the drum was transferred to the paper (the styrene-acrylic resin in the toner was insufficient). Effect of addition)
.

(Comparative Example 3) The toner and carrier are the same as Example IK, but dicumyl peroxide 0 is used as a curing agent for the carrier resin.
．． When the amount was less than 5% by weight, the charging ability began to decrease from about 50,000 sheets.

Moreover, when it exceeds 5% by weight, the amount of charge of the toner becomes too high and sufficient print density cannot be obtained. For this reason, it is necessary to set the toner'a degree to 5 to 6% by weight, but the resistivity of the developer increases, making it difficult to control printing by bias (influenced by the amount of peroxide added to the carrier).

[Example 2] All the composition ratios were the same as in Example 1 except that cyclized 1°4-cis polybutadiene (CLBR, Japan Synthetic Rubber) with a cyclization rate of 60% was used as the coating resin. Using the toner ◎ described in Example 1, a developer with a toner concentration of 3% by weight was prepared with a carrier having the above composition, and F
When a printing test was conducted using -6700D, the printing quality, printing stability, and stability of toner charge amount were almost the same as those shown in Example 1. However, the fusion of toner to the carrier was slightly more than in Example 1, and 1
After printing 1,000,000 sheets, it was 0.65% by weight (cyclization 1
．． Effect of 4-cis polybutadiene).

[Example 3] The toner described in Example 1 was used. The resin composition of the carrier was the same as that shown in Example IK, but the base iron powder was spherical 5T-20OR (Kanto Denka, average particle size 140 μm).
) and the amount used was the same as in Example 1 except that the amount used was 10 kg.

Printing tests were carried out using developers made of these toners and carriers. As a result, the printing quality, charging characteristics, and fusion of the toner to the drum were evaluated as follows: carrier (7) had a resistivity of 10°IQ-" (TS-). When using 20OR, it was as high as 10Ω·m), and it was not possible to obtain printing controllability and area printing characteristics by bias as effective as shown in Example 1 (influence of iron powder shape).

(7) Effects of the Invention According to the present invention, carrier filming and toner adhesion to the photoconductor drum can be reduced, void generation can be prevented when the toner is fixed, and the resistivity of the carrier can be reduced. By doing so, surface image printing characteristics can be improved and charging characteristics can be stabilized over a long period of time.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the operation of a laser printer, Fig. 2 is a graph showing the relationship between the charge imparting ability of carrier to toner and resistivity, and Fig. 3 is a developing brush to which a bias electric field is applied. FIG. 4 is a graph showing the relationship between the resistivity of the carrier and the resistivity of the carrier base iron powder, and FIG. 5A is a graph showing the relationship between the volume ratio of butadiene polymer/Fe 304 powder and the carrier Fig. 5B is a graph showing the relationship between the volume ratio of butadiene polymer/Fe3O4 powder and the ability of the carrier to impart charge to the toner; Fig. 6 is a graph showing the relationship between the number of prints and 3 is a graph showing the relationship between the amount of toner fused to the carrier and the amount of toner fused to the carrier. 1...Developer, 2...Carrier, 3...
Toner, 4... Photocondrum, 5... Charger, 6... Laser light, 7... Latent image portion, 8...
...Development part, 9...Developer, E, 10...Paper, 1
1... Fur brush, a... Carrier (average particle size 80 μm), b... Carrier (average particle size 14 oltm). Figure 3/Y Figure 4 Resistivity of carrier base iron powder (Ωcml procedure amendment stamped) September 1980, 9E Commissioner of the Patent Office Kazuo Wakasugi 1, Indication of the case 1982 Patent Application No. 3290 No. 2, Name of the invention Powder developer for laser printers, 13. Person making the amendment Relationship to the case Name of the patent applicant (522) Fujitsu Limited 4. Agent (3 others) 5. Subject of the amendment ( 1) “Claims” column in the specification (2) “Detailed Description of the Invention” column in the specification (3) “Brief Description of Drawings” column in the specification (4) Drawings (first (Figure) 6. Contents of amendment (1) The scope of claims in the specification will be amended as a separate sheet. (2) (a) From lines 15 to 16 on page 12 of the specification, the words "and non-adhesive toner" are deleted. (b) On page 13, line 2 of the same page, ``Weight ratio = 14J'' is corrected as ``volume ratio = 1: IJ''.
I am corrected. ) On page 24, lines 12-13, "for this purpose" is corrected to "K is used to optimize the amount of charge on the toner." (e) On page 24, line 14, "ga" is corrected to ".Also, the degree of hardening is high<too oaky." (3) In the Yusong Dynasty on page 27, line 13, li'12...
Add a fuser. (4) Correct the attached Tooshi Shuho in Figure 1. 7. List of attached documents (1) Amended claims 1 copy (2)
Corrected drawing (Figure 1) 1 copy 2, Claim 1, Magnetic material for a laser printer, characterized in that it contains carrier particles formed by coating iron powder as a base material with a butadiene polymer in which Fe3O4 powder is dispersed. Brush developer. 3. The butadiene polymer used to coat the iron powder of the carrier base material has a number average molecular weight of 1% or more of 1,2-polybutadiene having side chain double bonds in the polymer chain, and has a number average molecular weight of i.
o,ooo~200,000 polymer, 1.4-
A patent claim for a cyclized copolymer of styrene or acrylonitrile containing 50% by weight or more of cis-polybutadiene, which is coated with an organic peroxide and cured by heat treatment. The developer according to range 1 or 2. 4. The developer according to any one of claims 1 to 3, wherein the carrier particles have an average particle diameter of 50 to 500 μm. ] Fe3 dispersed in the resin of the carrier coating layer
The developer according to any one of claims 1 to 4, wherein the O4 powder has an average particle size of 0.1 to 1.0 μm. 6. The developer according to any one of claims 1 to 5, wherein the volume ratio of the butadiene polymer to Fe3O3 in the carrier coating layer is 8 to 2:1. 1 U The thickness of the carrier coating layer is 0.1 to 10 μm
The developer according to any one of claims 1 to 6. 1. The developer and image side according to claim 1, wherein the peroxide added to the carrier coating polymer is 0.5 to 5.0 parts by weight per 100 parts by weight of the polymer. 1 The epoxy resin, which is the main component of toner, has a melting point of 60
℃ ~ 160℃, weight average molecular weight] 00o ~ 10.00
2. The developer according to claim 1, wherein the developer is a bisphenol A/epichlorohydrin type epoxy resin containing 4% by weight or less of bisphenol A glycidyl ether having a polymerization degree of 0 and a degree of polymerization of 0. 10. The styrene-n-butyl acrylate resin contained in the toner has a softening point of 100 to 150°C, a weight average molecular weight of io, ooo-ioo, ooo, and a volatile content of 0.
．． The developer according to claim 2 or 9, which has a content of 5% by weight or less. 11. The developer according to any one of claims 2.9 and 10, wherein the toner has an average particle size of 5 to 30 μm.

Claims (1)

[Claims] 1. Fe; 0. A toner whose main component is an epoxy resin and contains a styrene-loop-tyl acrylate resin is mixed in an amount of 1 to 6% by weight based on the weight of the carrier, into carrier particles coated with iron powder as a carrier base material using a butadiene polymer dispersed in powder. A powder developer for laser printers, which is characterized by: 2. A cyclized copolymer of styrene or acrylonitrile used to coat the iron powder of the carrier base material, which is coated with an organic peroxide added to this polymer and cured by heat treatment. , claim 1
Developer described in section. 3. The developer according to claim 1 or 2, wherein the carrier particles have an average particle diameter of 50 to 500 μm. 4. Fe dispersed in the resin of the carrier coating layer
The developer according to any one of claims 1 to 3, wherein the average particle size of the 104 powder is 0.1 to 1.0 μm. 5. The developer according to any one of claims 1 to 4, wherein the volume ratio of the butadiene polymer to Fe504 in the carrier coating layer is 8 to 2:1. 6. The thickness of the carrier coating layer is 01 to 10 μm.
The developer according to any one of claims 1 to 5. 7. The developer according to claim 2, wherein the peroxide added to the carrier coating polymer is 0.5 to 5.0 parts by weight based on 100 parts by weight of the polymer. 8. The epoxy resin, which is the main component of toner, has a melting point of 60.
°C to 160 °C, weight average molecular weight 1000 to 10.00
2. The developer according to claim 1, wherein the developer is a bisphenol A/epichlorohydrin type epoxy resin in which bisphenol A glycidyl ether having a polymerization degree of 0 and a degree of polymerization of 0 is 4 or less by weight. 9. The styrene-looptyl acrylate resin contained in the toner has a softening point of 100-150° C. or the developer according to item 8. 10. The developer according to claim 1.8.9, wherein the toner has an average particle size of 5 to 30 am.