JPH02300762A - One-component developing method - Google Patents

Abstract

PURPOSE:To obtain sharp images having a high density and good quality by first mixing a charge control agent with a 1st binder resin having a high mol. wt. in a 1st stage, then melting and kneading the same with a 2nd binder resin having a low mol. wt. together with a coloring agent and grinding the resulting mixture in a 2nd stage. CONSTITUTION:The charge control agent is first mixed with the 1st binder resin having the high mol. wt. in the 1st stage. This mixture is melted and kneaded with the 2nd binder resin of the relatively low mol. wt. and ground in the 2nd stage. The developer obtd. in such a manner has good electrostatic charge efficiency and a narrow charge distribution as the shielding effect of the charge control agent and the dislodgment of the charge control agent due to the coloring agent is prevented and the uniform dispersibility of the charge control agent is improved. The sharp images faithful to originals are obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a one-component development method for developing electrostatic latent images.

BACKGROUND TECHNOLOGY Methods for forming electrical latent images are well known. For example, in electrophotography, a photoconductor layer is usually charged and then a light image based on an original image is irradiated to form a light-irradiated area. The electrostatic charge image is developed or erased to form an electrostatic latent image. Then,
This latent image is developed with a developer called toner. Methods for developing latent images include a two-component developing method using a developer consisting of toner and a carrier, and, for example, U.S. Pat.
In addition to the dielectric development method described in , 909.258, the touchdown method described in 3.1.66.432, charge development, jumping method, impression method, powder One-component development methods using only toner are known, such as the cloud method and the fur brush method.

Conventionally, toners used in the -component development method are made by mixing resins such as polystyrene, styrene-butadiene copolymer, polyester, and pigments or dyes such as carbon black and phthalocyanine blue with colorants and charge control agents, and then melting the mixture. After kneading, 177 ITl is pulverized to 30 ITl.

Problems to be Solved by the Invention One-component developing method using only toner has become popular in recent years because it uses a developing device with a simple configuration and it is easy to avoid developer deterioration as in two-component developing method. has been researched and commercialized.

However, since the -component development method does not use a carrier, it is difficult to form a uniform layer of toner and control the transport involved in supplying the toner to the electrostatic latent image surface, as well as to apply and control sufficient charge to the toner. It exists.

FIG. 2 is a schematic diagram showing the form of toner single layer formation and conveyance in the currently widely used one-component development method.

FIGS. 2(a) and 2(b) show the use of the blade 71 as a toner further regulating member, and FIG. 2(C) shows the use of the roll 72.
d) shows a case where the toner layer is regulated and controlled by the magnetic brush 73 from the magnetic blade 10. At this time, the developer 4 is often charged by frictional charging between the toner regulating member 71, 72, 73 and the developer carrier 5. Therefore, in the above embodiment, in order to impart sufficient charge to the toner, it is necessary to stably form the toner into a thin layer. However, no matter how thin the toner layer is, there are disadvantages such as lower charging efficiency and charge distribution between the toners compared to the two-component development method using a carrier. In this case, image unevenness, blurring, fogging, etc. often occur, and it is even more difficult to always achieve stable image reproduction against environmental changes over time.

In the past, studies have been made on the toner itself and charge imparting members (means) in order to improve the above-mentioned drawbacks, but they have not yet reached a sufficient level. For example, in order to impart sufficient charge to l-toner, it is effective to configure the toner itself and the charge imparting member with materials that are different in terms of charge series, but what is more important is how to This means that even if the distance is far away, it cannot be put to practical use unless the l-ner charge rises quickly. Furthermore, toner charging and transport are
They are closely related, and if the toner charge distribution is wide, it may cause uneven conveyance, spillage, etc.

Further, the charge of the toner must be stable against changes in the environment over time, but even when conventional so-called charge control agents are used, the level is not satisfactory. On the other hand, in order to stabilize the toner charge, the charged bone! j.

It is also possible to use the member by treating it with various charge control agents, but in this case, the composition is limited from the viewpoint of processability, strength, etc., and furthermore, the charge distribution of the toner tends to widen, although the reason is not clear. However, there are disadvantages such as the fact that there are cases in which the toner is not used properly, and that it may not have an adverse effect on the conveyance of the toner.

The present invention has been made in view of the above-mentioned problems in the -component development method.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a developing method that can produce images that are clear and faithful to the original.

Another object of the present invention is to provide a developing method with excellent repeat stability in image reproduction.

Still another object of the present invention is to provide a developing method that exhibits excellent stability of image reproduction against environmental changes such as temperature and humidity.

Means for Solving the Problems The present inventors have discovered that the above-mentioned problems in the -component development method can be improved when a toner manufactured by a specific method is used, and the present invention has been completed. reached.

In the present invention, a layer forming portion is brought into contact with a developer carrier to form a uniform layer of developer on the developer carrier, and the developer carrier is transferred to a photoreceptor that holds an electrostatic latent image. In a one-component development method in which an electrostatic latent image is visualized by moving a developer to a photoconductor, the developer is treated by mixing a charge control agent with a first binder resin. The obtained powder is mixed with a second binder resin and a colorant, melted, kneaded, and pulverized, and the molecular weight of the second binder resin is It is characterized by having a molecular weight higher than that of the binder resin in No. 2.

The present invention will be explained in detail below.

The developer used in the one-component developing method of the present invention is manufactured as follows. That is, in the first step, a charge control agent is mixed with a first binder resin. For example, the charge control agent and the first binder resin are mixed, melted, kneaded, and pulverized, or the charge control agent is mixed with a solution of the first binder resin, and the solvent is removed to form particles. become

Subsequently, in the second step, the powder obtained in the first step is mixed with a second binder resin and a colorant, and melted.
Knead and grind.

In the present invention, a known first binder resin is used. Specifically, styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene, butadiene, and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl acetate, methyl allicrate, α-Methylene aliphatic monocarboxes such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, etc. Examples include homopolymers or copolymers of acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl butyl ether, and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone.
Particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, and styrene-maleic anhydride copolymer. Examples include polymers, polyethylene, and polypropylene.

These first binder resins have a higher molecular weight than the second binder resin, for example, the number average molecular weight expressed by the GPC method is higher than that of the second binder resin. The bigger the better.

In addition, when the molecular weight distribution has a two-way or three-way distribution,
Any resin may be used as long as it has a molecular weight larger than the peak on the lowest molecular weight side. Furthermore, the molecular weight of these resins is
The second binder resin may have a molecular weight larger than that of the second binder resin, but it is preferable to use one having a molecular weight of about 1.5 times or more than that of the second binder resin, since this is more effective.

The preferred range of the average molecular weight of the first binder resin is 10.
000 to 200,000.

On the other hand, the charge control agent to be mixed with the first binder resin may be added in the form of micelles or pigments in the toner by about 0.01 to
A known method that is distributed in units of approximately 3 questions is used. Specifically, metal chelates such as metal complex dyes, quaternary ammonium salts, tetraphenyl boron derivatives such as sodium and potassium tetraphenyl boron, various electron-withdrawing/donating inorganic powders, and inorganic materials surface-treated with polar substances. materials, polar polymer beads, etc. can be used.

In the present invention, the blending amount of the charge control agent is preferably in the range of 1 to 50% by weight based on the first binder resin.

In the second step, the powder obtained in the first step is mixed with a second binder resin and a colorant, and melted and kneaded. Those exemplified as the binder resin in No. 1 can be used. The second binder resin may be made of a different type of resin than the first binder resin, but it is preferably made of the same type of resin.

Furthermore, the molecular weight of the second binder resin needs to be lower than the molecular weight of the first binder resin, as described above. usually,
The molecular weight of the second binder resin is 1.000 to too, ooo
Preferably, it falls within this range.

On the other hand, known colorants can be used as the colorant.

Specifically, for example, carbon black, nigrosine dye, aniline blue, calcoyl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C,1, Pigment Red 48:l, C,I.

Pigment Red 122, C, I Pigment Red 57, C, 1, Pigment Yellow 97, C,
1, Pigment Yellow 12, C,1, Pigment Blue 15:1, C,'1. Pigment Blue 15:3, etc. can be exemplified as a representative example.

The blending amount of these colorants is appropriately set in the range of 1 to 20% by weight.

The blending amount of the powder obtained in the first step is preferably in the range of 1 to 50% by weight.

The powder obtained in the first step, the second binder resin, and the charge control agent can be melted and kneaded using a pressure kneader, a Banbury mixer, an extruder, or the like.

The melted and kneaded material is then pulverized, and as a pulverizing means, for example, a jet mill or the like can be used.

It is also possible to add an appropriate amount of a fluidity imparting agent such as colloidal silica to the l-ner as an additive for further increasing the fluidity of the l-ner.

The purpose is to improve the above-mentioned electrical properties and storage stability, including the powder fluidity of the developer, or to prevent toner filming on the photoreceptor and to improve the cleaning performance of the toner. Additionally, other external additives may be used. External additives include long chain fatty acids such as stearic acid and their esters, amides, and metal salts, aromatic acids such as terephthalic acid and their esters, amides, and metal salts, as well as tin oxide and fluorine. Fine powders of carbonized graphite, silicon carbide, silica, aluminum oxide, titanium dioxide, zinc oxide, zirconium oxide, etc., fine powders of fluorine resins, acrylic resins, etc., polycyclic aromatic compounds, waxy substances, crosslinked or non-crosslinked Crosslinked resin fine powder or the like can be used.

Next, a one-component developing method for visualizing an electrostatic latent image using the developer produced as described above will be described.

FIG. 1 is a schematic cross-sectional view of a developing device for carrying out the present invention. In FIG. 1, a developing machine body 2 installed near the electrostatic latent image holder 1 has a hopper 3 having an opening on the side of the electrostatic latent image holder 1. The developer 4 is stored in the lower part of the hopper 3, and a portion of the developer carrier 5 protrudes toward the electrostatic latent image carrier 1 from the opening. Contacted layer forming auxiliary roll 8
is accommodated. The developer carrier 5 is made of a roll or belt having a smooth or moderately uneven surface,
For example, it is rotated in the direction of the arrow by a drive system (not shown). In addition, if necessary, the bias power supply 6 provides direct current and/or
Or an AC bias voltage is applied. Further, a mechanical layer regulating member is provided on the developer carrier 5 to control uniform coating of toner particles in a laminated state of one or two layers. The layer regulating member 7 is composed of a blade, a roll, a brush, etc., and in addition to regulating the layer, it can apply a charge (=1) due to contact with the developer 4, friction, etc. Furthermore, it can reduce the toner charge by ion irradiation, etc. In this case, it is preferable to use a material for the layer regulating member 7 that is located at an appropriate distance from the developer 4 on the charging series. and/or AC power supply 9
are connected so that an electric field is generated between the developer carrier 5 and the layer regulating member 7. This electric field transmits minute vibrations to the toner 4 sandwiched between the developer carrier 5 and the layer regulating member 7, thereby preventing a decrease in the fluidity of the developer and uniformly distributing the toner on the developer carrier. In addition to being free when forming a single layer of thin toner, it may be advantageous in that it can exert an amplification effect or a charge injection effect when the charge is applied by contact or friction.

In the developing device having the above configuration, the developer 4 formed into an ultra-thin layer by the layer regulating member 7 is applied to the developer carrier 5 by electrostatic attraction such as mirror image force, polarization force, etc. It is carried and conveyed by force, reaches the development area, and comes into contact with the electrostatic latent image holder 1, or faces the electrostatic latent image holding member 1 with a small gap in a non-contact state. Thereby, the developer 4 is transferred to the electrostatic latent image by an electric field formed between the electrostatic latent image carrier 1 and the developer carrier 5 due to the electrostatic latent image and the DC and/or AC bias voltage applied as necessary. It is deposited according to the latent image pattern and visualized.

Function: In the present invention, since the toner produced as described above is used, the drawbacks of the -component development method are improved, charging efficiency is improved, and charging stability is achieved. In the present invention, although the mechanism of action of charge stabilization is not necessarily clear, the charge control agent is first mixed with the first binder resin having a high molecular weight in the first step as described in Section 2,
In the second step, it is melted and kneaded together with a colorant and a second binder resin having a relatively low molecular weight, and is crushed. (1) prevents the charge control agent from falling off, and (2) improves the uniform dispersion of the charge control agent, resulting in extremely good charging efficiency and narrow charge distribution. As a result, it is presumed that when one-component development is performed using such a developer, the charging/transportation of the developer is stably controlled.

Example Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 Treatment of charge control agent Styrene-n-butyl meth 90 parts by weight Acrylate (70/30) copolymer (Mn-35,000, Mw-90,000) Chromium-based metal complex (Aisens 10 parts by weight Pyron black T
R.H.

(manufactured by Odugaya Kagaku ■) The above components were melt-kneaded at 110°C using a roll mill. After cooling the kneaded material, it was coarsely pulverized using a hammer mill to obtain a charge control agent-containing resin powder (A) having an average particle size of 2 mm.

Preparation of developer (a) Styrene-n-butylmeth 90 parts by weight Acrylate (70/30) copolymer (Mn-1,5,000, Mw-40,000) Carbon black 6 parts by weight Resin powder containing charge control agent (A> 10 parts by weight The above components were melt-kneaded at 120°C with a roll mill. After cooling the mixture, it was coarsely pulverized with a hammer mill, then finely pulverized with an air jet, and classified to give a black powder with an average particle size of 12 Got toner.

Hydrophobic silica (1?972,
1.0 part by weight (manufactured by Nippon Aerosil Co., Ltd.) was added and mixed using a high-speed mixer to prepare a developer.

Development was carried out using this developer under the following conditions.

That is, the developing device shown in FIG. 1 was placed in a copying machine (Fuji Xerox model PX-2300 modified machine), the above-mentioned developer was put into the hopper 3 of the developing device, and close-range development was carried out in the with mode. In the above-mentioned developing device, the developer carrier 5 is made of a phenol resin in which graphite is dispersed and whose electrical resistivity is controlled to about 10I0Ω·cm.
The layer regulating member 7 used was a stainless steel blade having a thickness of 0.1 mm and coated with modified silicone rubber to a thickness of 1 mm. Further, the layer regulating member 7 was brought into contact with the developer carrier 5 at a pressure of about 150 g/cm. This developing device is manufactured by Fuji Xerox PX.
-2300 modified machine was installed, and close-up development was performed in the with mode. The development conditions at this time were as follows: the distance between the developer carrier and the latent image carrier was set to 200 mm, the circumferential speed of the developer carrier 17 was set to 100 mm/sec, and the developing bias was set to 300 mm/sec for the DC component and 300 mm/sec for the AC component. 2.4 KVp
-p (2.5 KHz) was applied.

The image obtained by development under a normal temperature and normal humidity environment (22° C., 55% RH) was clear with excellent resolution and no fog. Amount of toner conveyed on the developer carrier at this time (toner weight per unit area of one layer on the developer carrier)
was 0.65 mg/cd. Furthermore, when the chargeability of the toner on the developer carrier was measured using a charge spectrum method, the average charge amount of the toner -g, oμc/g, and the amount of toner with opposite polarity: 2. Owt% was good. Stable image quality could be maintained even when the above developer was used to repeatedly reproduce images on 5,000 sheets.

Furthermore, when development was carried out in a high temperature and high humidity environment (30°C, 185% R1+), the result was a normal temperature and normal humidity environment (22°C, 55% R1+).
An image with almost the same quality as in the case of () was obtained, and 500
There was no significant change even in the repeated image reproduction operation for 0 images. At this time, the toner conveyance amount, average charge amount, and reverse polarity l/toner amount were 0 and 64 mg/cm, respectively.
-7, Oμc/g, 1. ．． 5 wt%, which hardly changed over time.

Next, we looked at image reproducibility in a low-temperature, low-humidity environment (10°C, 15% R11), and found that
A good image similar to that obtained at 5% RH) was obtained. Furthermore, even when the image reproduction operation was repeated for 5,000 images under these environmental conditions, good image quality without fogging could be maintained. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount were also stable, 0.68 mg/cJ, respectively.
-9.0 μc/g, 2.3 wt%.

Example 2 Example 1-- except that a surface alumite-treated aluminum sleeve was used as the developer carrier in Example 1.
Evaluation was conducted in the same manner as in Example 1 using the same developing device as in Example 1 and using the same developer as in Example 1. As a result, a fog-free and clear image of good quality was obtained.The amount of toner conveyed, the average amount of charge, and the amount of reverse polarity toner were all 0.
64mg/cd, -8.5μc/g, 1.5wt
It was %. Also, under similar conditions including environmental changes, 10
Even when continuous image reproduction was performed for ,000 images, stable and good image quality was maintained.

Comparative Example 1 In Example 1, 1 part by weight of an untreated chromium-based metal complex was added instead of the charge control agent-containing resin powder (A), and a toner with an average particle size of 12/Zln was produced by the same manufacturing method as in Example 1. I got it.

For the above toner, add 1 portion of hydrophobic silica (1?-972).
% by weight was added and stirred with a high-speed mixer to prepare a developer. When this developer was subjected to image evaluation using the same developing device as in Example 1 and under the same conditions, initially good images were obtained as in Example 1. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are each 0.60 mg/c+
ff, -'1.8 μa/g, 5. It was Owt%.

Furthermore, when repeated image reproduction operations were performed, 2000
Fogging and image blurring became noticeable, resulting in images of considerably low quality. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are 0.65 mg/c, respectively.
-5.0 μc/g, L8J wt%.

Next, this developer was applied in a high temperature and high humidity environment (30°C, 85% R1
When image reproduction was performed in step 1), defects such as thickening of thin lines and fogging were noticeable. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are each 0.59.
mg/crl, -3.1μc/g, 18.0wt
%Met. Furthermore, in a low temperature and low humidity environment (10℃, ■5% R1
When I performed the image reproduction operation with +), the obtained image was as follows.
The image density was low and the fog was quite noticeable and was of low quality. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are 0.85 mg/c/, -9, and 3μ, respectively.
c/g, 17.3 wt%.

Example 3 A charge control agent obtained by mixing a chromium-based metal complex (Eisenspiron Black TRH, manufactured by Hodogaya Kagaku ■) in the same manner as in Example 1, except that resins having different molecular weights shown in Table 1 were used. A containing resin powder was obtained. In addition, resin 9
10 parts by weight of the chromium-based metal complex was used relative to 0 parts by weight.

Table 1 Styrene-〇-butyl meth 90 parts by weight Acrylate (70730) copolymer (Mn=15,000, Mw-40,000) Carbon black 6 parts by weight Resin powder containing the above charge control agent 10 parts by weight The above components were carried out The mixture was melt-kneaded in the same manner as in Example 1.

After cooling the kneaded product, it was finely pulverized and classified in the same manner as in Example 1 to obtain a toner having an average particle size of 12.

To this toner, 1.0% by weight of hydrophobic silica (R972, manufactured by Nippon Aerosil Co., Ltd.) was added, and developers (b), (e) and (d) were obtained in the same manner.

When an image reproduction test was conducted on the above three types of developers under the same conditions as in Example 1, images of good image quality were obtained with all the developers regardless of the environment and aging. The toner transport properties and charging properties of each developer at this time were as shown in Table 2.

The following margin Comparative Example 2 Averaged by the same manufacturing method as Example 1, except that the resin used for the charge control agent-containing resin powder (A) was the same as that used for toner manufacturing. A toner with a particle size of 12 kats was obtained.

To the obtained toner, 1.0% by weight of hydrophobic silica (R-972) was added and stirred with a high-speed mixer to prepare a developer. When this developer was used to reproduce an image under the same conditions using the same developing device as in Example 1, a clear image without fogging was initially obtained.

At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are 0.64 mg/c/, -8.6 μc/g, respectively.
It was 3.8 wt%.

Next, apply this developer under a high temperature and high humidity environment (30°C, 185%R).
When the image reproduction operation was performed in H), there was no fogging, but an image with thick thin lines and poor resolution was obtained.

At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount were 0.62 mg/cJ, -45 μc/g, respectively.
4. It was Ovt%. Furthermore, a low temperature and low humidity environment (10℃,
When an image reproduction operation was carried out at 15% RH), the obtained image had no fog, but the image density was low and the fine line reproducibility was poor. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are each 0.75 mg/c.
J, -10.0 μc/g, 3.2 wt%.

Example 4 Treatment of charge control agent Styrene-n-butylmeth 90 parts by weight Crery 1-(70/30) copolymer (Mrr50,000,
Mw”90,000) Potassium tetraphenyl boron
10 parts by weight of the above components were treated in the same manner as in Example 1 to obtain a charge control agent-containing resin fine powder (P).

Preparation of developer Styrene-〇-butylmeth 90 parts by weight Acrylate (70/30) copolymer (Mrr20,000, Mw-35,000) Macenta pigment 3 parts by weight (Brilliant.
Carmine 6B.

C, 1, Pigment Red 57) Charge control agent-containing resin powder (1') 1.0 parts by weight The above acid was treated in the same manner as in Example 1 to obtain a toner having an average particle size of 12.

Add 1 portion of hydrophobic silica (R-972) to this toner.
．． 0% by weight was added and stirred with a high speed mixer to prepare a developer. When this developer was used to reproduce an image under the same conditions using the same developing device as in Example 1, a clear magenta image with excellent resolution and no fog was obtained. The toner conveyance amount, average charge amount, and reverse polarity toner amount at this time were 0.60 mg/c, -9', 5 μc7g, and 2.
It was Owt%. Moreover, the repeatability including environmental changes was also very stable.

Comparative Example 3 In Example 4, 1 part by weight of untreated potassium tetraphenyl boron was added instead of the charge control agent-containing resin powder (F), and a toner with an average particle size of 12% was produced by the same manufacturing method as in Example 1. Obtained. For the above toner, hydrophobic silica (R
-972) was added in an amount of 1.0% by weight, and the mixture was stirred with a high-speed mixer to prepare a developer.

When this developer was used to reproduce an image under the same conditions using the same developing device as in Example 1, a good image was initially obtained as in Example. The amount of toner conveyed at this time,
The average charge amount and reverse polarity toner amount are O, 83 mg, respectively.
/a stitch, -8.2 μc/g, 3.2 wt%.

Furthermore, when repeated image reproduction operations were performed, 2000
Fogging and image blurring became noticeable, resulting in images of considerably low quality. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount were 0.78 mg/cJ, respectively.
-5.2 μc/g, 1 g, 3 wt%.

Next, this developer was applied in a high temperature and high humidity environment (30°C, 85% R1
When the image reproduction operation was performed in step 1), although there was no fogging, the thin lines became noticeably thicker, resulting in an image of low quality. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are each 0. [10mg/cJ, -5.2μc
/g, 3.6 wt%. Furthermore, when an image reproduction operation was carried out in a low temperature and low humidity environment (10° C., 115% R11), the obtained image was of low quality with low image density. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount were 0.68 mg/cd and -10.5, respectively.
μc/g, 5. [i wt%.

Example 5 Treatment of charge control agent Styrene-〇-butylmeth 90 parts by weight Acrylate (70/30) copolymer (Mn-50,000, Mw-90,000) Bontron P-51 (Orient 10 parts by weight) ) The above components were treated in the same manner as in Example 1 to obtain a charge control agent-containing resin fine powder (G).

Preparation of developer Styrene-n-butylmeth 80 parts by weight Crery 1-(70/30) copolymer (Mrr15,000
, Mw-40,000) magenta pigment
3 parts by weight (Brilliant Carmine 613, C, 1, Pigment Red 57) Charge control agent-containing resin powder (G) 20 parts by weight The above components were treated in the same manner as in Example 1- to form a toner with an average particle size of 12 I got it.

To this toner, 0.7% by weight of silica powder (particle size: 1.6 mm+) treated with a quaternary ammonium salt was externally added and mixed to prepare a developer. Using this developer, copying machine (P
When image reproduction was performed using a modified X-2700 machine (manufactured by Fuji Xerox), a clear image without fogging was obtained. Furthermore, the repeatability including environmental changes was also very stable.

Example 6 Preparation of developer Styrene-n-butyl meth 90 parts by weight Acrylate (70/30) copolymer (Mn-20,000, Mw-35,000) Magenta pigment 6 parts by weight (Brilliant Carmine BB.

C, 1, Pigment Red 57) Charge control agent-containing resin powder (E) 10 parts by weight The above components were treated in the same manner as in Example 1 to obtain a toner with an average particle size of 7IEn.

Add 1 portion of hydrophobic silica (R-972) to this toner.
．． 8% by weight was added and stirred using a high speed mixer to prepare a developer. Using this developer, image reproduction was performed using the same developing device as in Example 1 and under the same conditions except that the AC bias component was set to 3 K V pp (3 KIlz). A clear magenta image without fogging was obtained. At this time, the toner conveyance amount, average charge amount, and reverse polarity toner amount are each 0.51. mg/cJ, -18,
5μc/g, 1. ．． It was 5 wt%.

Moreover, the repeatability including environmental changes was also very stable.

Comparative Example 6 In Example 6, 1 part by weight of untreated potassium tetraphenyl boron was added instead of the charge control agent-containing resin powder (F), and the average particle size was 77 f by the same manufacturing method as in Example 6.
I got fi toner. 1.8% by weight of hydrophobic silica (R-972) was externally added and mixed to prepare a developer.

This developer was placed in the developing device used in Example 1, and the layer formation and charging properties of the developer were evaluated. It showed almost the same characteristics as 6, but under a high temperature and high humidity environment (30℃,
With 85% R11), no layer was formed at all. When looking at the charging properties of the toner without layer formation, it was found that it was hardly charged. Furthermore, a low temperature and low humidity environment (10℃, 15% R
A similar evaluation was performed in 11), and although a layer was formed, the uniformity was poor.

Effects of the Invention In the present invention, as described above, as a developer, a charge control agent is first mixed with a first binder resin having a high molecular weight in the first step, and then compared with a colorant in a second step. Since the material obtained by melting, kneading, and pulverizing the second binder resin with a low target molecular weight is used, the charge control agent is difficult to fall off from the toner particles during development, and as a result,
Under conditions ranging from high temperature and high humidity to low temperature and low humidity, it is possible to obtain clear, high-density, high-quality images with no background stains or fog. In addition, even in repeated image reproduction operations, the toner transportability, average charge amount, and amount of reverse polarity toner are stable, and good image quality can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a developing device for carrying out the present invention, and FIGS. 2(a) to 2(d) are schematic diagrams of a developing device used in a -component development method, respectively. ■...Electrostatic latent image holder, 2...Developing device, 3...
Hopper, 4...Developer, 5...Developer carrier, 6...
...Bias power supply, 7.. Layer regulating portion shrine, 8.. Layer formation auxiliary roll, 9.. Power supply, 10.. Magnetic material blade. Patent applicant Fuji Xerox Co., Ltd. Agent
Patent attorney Tsuyoshi Nabe (a) (C) (b) (d)

Claims (1)

[Claims] (1) A layer forming member is brought into contact with the developer carrier to form a uniform layer of developer on the developer carrier, and the developer carrier is placed opposite to the photoreceptor that holds the electrostatic latent image. In a one-component development method in which an electrostatic latent image is visualized by moving a developer to a photoreceptor, the developer contains a charge control agent as a first component.
A powder obtained by mixing with a second binder resin and a second binder resin and a colorant, melted, kneaded, and pulverized, and A one-component developing method, wherein the molecular weight of the binder resin is higher than the molecular weight of the second binder resin.