JPS62967A - Developing method - Google Patents

Abstract

PURPOSE:To stabilize the quantity of frictional electrostatic charge by a toner and toner carrying body and to uniformly and thinly coat the toner on the surface of the toner carrying body by using the negative electrostatic charge non-magnetic one-component color toner consisting of a resin binder and a pigment subjected to a surface treatment with a silane coupling agent having a chlor group. CONSTITUTION:An electrostatic latent image holding body 5 which holds an electrostatic latent image on the surface and the toner carrying body 1 are disposed at the specified spacing provided therebetween in a developing part and the negative electrostatic charge non-magnetic one-component color toner 4 contg. at least the binder resin and the pigment subjected to the surface treatment with the silane coupling agent having the chlor group is coated on the toner carrying body 1 to the thickness thinner than the above-mentioned spacing by an elastic blade 2 brought into press contact with the surface of the body 1. The coated toner is transferred onto the electrostatic latent image holding body 5 and is developed in the developing part. The binder resin is a styrene/ acryl copolymer having >=50 deg.C glass transition point and 110-160 deg.C softening point and colloidal silica is preferably added at 0.05-2pts.wt. to the toner.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a developing method for visualizing an electrostatic latent image formed on a photoreceptor or dielectric in an electrophotographic device or an electrostatic recording device. .

[Technical background of the invention and its problems]

In electrophotographic devices or electrostatic recording devices, a two-component developing method consisting of toner and carrier has been widely used due to its good image quality in order to visualize the electrostatic latent image formed on a photoreceptor or dielectric material. It is used in

However, on the other hand, there are drawbacks common to the two-component developing methods described below. In other words, ■toner is
Frictional charges are received due to mutual friction between toner and carrier, but in this case, if used repeatedly over a long period of time, the carrier surface becomes contaminated with the toner composition, and as a result, it becomes impossible to acquire sufficient charge. . - The mixture ratio of toner and carrier must be adjusted within a predetermined range, but if psychokinesis is used for a long period of time, the mixture ratio will fluctuate and deviate from the predetermined range. (2) Generally, iron powder or glass beads with oxidized surfaces are often used as carriers, but in this case, the surface of the photoreceptor is mechanically damaged by these carriers.

For this reason, various developing methods using a single-component toner consisting only of toner have been proposed. Above all,
A number of development methods have been proposed using toners that are magnetically sensitive and are generally called magnetic toners.
Those based on US Pat. No. 3,909,258, No. 1, No. 4,121,931, etc. have been put into practical use. However, these methods also have the following drawbacks. In other words, ■Since magnetic toner with relatively low resistivity is used, it is difficult to electrostatically transfer the developed image on the electrostatic latent image to a supporting member such as plain paper, especially in a humid atmosphere. Inability to obtain sufficient transfer; - Because the toner contains a large amount of magnetic powder, color toners other than dark colors cannot be obtained;
It has drawbacks such as:

However, recently, a developing method using a single-component toner that does not contain magnetic powder and has a high resistivity has been attracting particular attention. For example, U.S. Patent No. 2895847, U.S. Pat.
Examples include methods based on the touchdown method, impression method, and jumping method described in publications such as No. 24. In these methods.

It uses the conventional toner used in two-component development.

However, in this case, as discussed below.

- Various problems associated with the developing method using minute toner are unavoidable.

The problem with whistle 1 is frictional charging.

In other words, the toner must efficiently form a charge amount on the toner carrier and in an extremely short period of time necessary to visualize the electrostatic latent image formed on the photoreceptor drum or dielectric material without contact. For example, when a selenium photoreceptor drum is used, the amount of charge between the toner and the toner carrier required to visualize the image is -0.5 to 15 μC.
/II.

However, when a toner used in a conventional two-component development method is used and frictional charging is performed between a toner carrier and the toner, a sufficient amount of charge to form a visible image cannot be obtained. The reason for this is that the toner used in conventional two-component development requires sufficient time for frictional charging between the toner and carrier to obtain the amount of charge necessary to form a visible image. In contrast, the frictional charging time between the toner and the toner carrier is short. This is because the amount of charge necessary to obtain visualization is not obtained.

The second problem is that the toner is applied extremely thinly and evenly to the surface of the toner carrier.

That is, for the toner carrier 1 shown in FIG.
The toner present in the toner container is conveyed by the rotation of the toner carrier and is evenly and thinly applied to the surface of the toner carrier by one elastic plate. For this reason, the toner is required to have good fluidity and agglomeration resistance.

However, although the toner present in the toner container is conveyed by the rotation of the toner carrier, it sometimes becomes cohesive and becomes lumpy, so there is a problem that the toner is not applied to the surface of the toner carrier.・Also, the toner transported by the rotation of the toner carrier is suddenly subjected to high pressure when the pressure is applied between the first elastic blade and the toner carrier. ! #The toner softens and sticks to the surface of the toner carrier due to heat friction. The existence of this fixed paddle toner is responsible for the toner.

There is a problem that prevents toner from being applied thinly (evenly) on the surface of the press.The causes of these problems include the low softening point of the binder resin of the toner and the low glass transition point. .

Furthermore, the higher the softening point, the higher the fixing temperature.

There are problems that hinder its use in ordinary office copying machines.

Furthermore, as a third problem, color toners must not only overcome the above problems and have excellent physical and chemical properties, but also must satisfy the following conditions. (1) In the case of multicolor superposition,
The toner must be highly transparent.

Like [2) Each color toner must have excellent melt-mixability.

(3) Good resistance to 1 minute light in order to faithfully reproduce the original.

Also, in the case of funky natural colors that use a single color.

(1) Having secret power is required.

Moreover, in color toners, when determining the polarity of the tripo charge of the toner due to frictional charging between the toner and the toner carrier and between the toner and the elastic blade, it is used as a charge control agent in the art. Known substances are often difficult to use.

Therefore, the toner that is to be developed into a positively charged latent image cannot be developed unless it is negatively charged.

Therefore, the selection and combination of binder resin and pigment is extremely important.

However, pigments with excellent spectral properties often exhibit positive charge. Therefore, a toner containing a combination of a positively charged pigment and a negatively charged binder resin does not produce a good image due to development fog.

A typical example is β-type phthalocyanine, a blue pigment. β-deaf cyanine has excellent spectral properties, but since it is positively charged, toners using this pigment have small particles between the toner particles, between the toner and the carrier, and between the toner and the toner. Between the toner carrier, the toner, and the elastic blade, the charge generated on the surface of the toner particles becomes loose, which tends to cause problems such as fogging and toner scattering.

Further, such a failure appears as a noticeable development when a large number of copies are made, and the result is that the copying machine is not suitable in practice.

[Purpose of the invention]

The object of the present invention is to provide a negatively charged non-magnetic material which improves the above-mentioned problems.
It is an object of the present invention to provide a new method of using component color toners.

Another object of the present invention is to solve various problems associated with conventional negatively charged toners, to uniformly form a thin layer on a toner carrier, to have a stable triboelectric charge amount, and to provide R tribostatic toners. It is an object of the present invention to provide a developing method using toner having a sharp and uniform quantity distribution. Still another object of the present invention is to provide a developing method that visualizes an electrostatic latent image faithfully and with high quality without development fog and without toner scattering around the edges of the latent image. That's true.

[Summary of the invention]

The present invention forms a thin layer of negatively charged non-borous toner by an elastic blade pressed onto a toner carrier,
A developing method that provides a stable triboelectric charge amount, a sharp triboelectric charge distribution, a faithful electrostatic latent image, no development fog, no scattering around the edges of the latent image, and a sharp image with high resolution. Make it the gist.

That is, in the present invention, % 'K t! An electrostatic image carrier that holds an F I image on its surface and a toner carrier that carries a non-magnetic component color toner on its surface are arranged at a constant interval in a developing section, and binder resin and chlorine groups are A negatively charged non-magnetic component color toner containing at least a pigment whose surface has been treated with a silane coupling agent is transferred to the gap by an elastic blade pressed onto the toner carrier.
This is a development method in which the toner is coated on a toner carrier to a very thin thickness, and the toner is transferred to the electrostatic image holder in a development section for development. In particular, the binder resin has a glass transition point of 50°C or higher and a softening point of 110°C to 16°C.
It is preferable to use a snurene-acrylic copolymer having a temperature of 0° C., and further add 0.05 to 2 parts by weight of colloidal silica to the toner.

The binder resin used in the present invention may be any resin commonly used in toners, but styrene-acrylic copolymers are particularly excellent from the viewpoints of transparency, charging characteristics, viscoelasticity, etc. In particular, it is desirable that the styrene component ratio in the styrene-acrylic copolymerization is 501 or more and 95 or less. Acrylic components used in the present invention include: acrylic acid and methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate,
Acrylic acid esters such as heptyl acrylate and octyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, inbutyl methacrylate, and pentyl methacrylate.

All conventionally known acrylic acid and derivatives thereof, acrylic esters and derivatives thereof, such as methacrylic esters such as hexyl methacrylate, heptyl methacrylate, and octyl methacrylate, can be used.

It is also possible to crosslink the styrene-acrylic copolymer used in the present invention using a crosslinking agent.

As the crosslinking agent, all conventionally known divinyl compounds, diallyl compounds, diyliptenate, bisepoxy compounds, etc. can be used.

In addition, low molecular weight polyethylene, low molecular weight polypropylene,
A mixture of ethylene vinyl acetate copolymer, higher fatty acid, polyamide resin, polyester resin, etc. can also be used.

Examples of the silane coupling agent having an O group used in the present invention include H, C=CH8tca.

H,C舅CHCH,8i(CH3)C1@H,C-CH
CH, Si (CH8), CJ (H, C-CHCH
,)*SSCl2 (H,C), -C-COO(Cm*), S i
(CHs) C11CH3 CJ (CHl), S l (OCR, N.

Cj(CH,), 5i(CH,)CJ.

CI (CH,), 8 i (CH,) (0CR8
).

Cl (CHth S i (CH-(0CJIs)
Go CI (CH,), S i (OCR,)sCI
Examples include (CHl)s 81 (OCt Hs )s. These silane coupling agents may be used up to 1 m, or two or more types may be mixed.

The colorant used in the present invention is, for example, Pigment Yellow 24. represented by Chromophta Yellow A2R. Solvent yellow 88. represented by Orazol Yellow 20LN etc. Pigment Yellow 17 represented by Seika First Yellow 2400 etc.
．． Pigment Red 122°, represented by Kind Magenta 12V-6832; Pigment Red 238, represented by Permanent Carmine F5B; Pigment Red 57, represented by Brilliant Carmine 6B.
Pigment Red 48. represented by Fast Red 2BK etc. Pigment Red 49, represented by Seika First Red LR116, #Solvent Blue 49, represented by Orazole Red Blue BLN, etc. Tsuruberto Blue 6+, represented by Ceres Blue GN, etc.
Solvent blue represented by Ceres Blue Rfi etc. 8. Heliogen Blue L7040. L7080. Cyanine Blue KR8゜ Pigment Blue represented by Cyanine Blue KBN etc. 15:3. Examples include W-charged colorants. Other examples include white pigments such as titanium oxide, lithopone, and zinc white.

Furthermore, there is no problem in using negatively charged colorants.
In addition, as a method for surface treating a coloring agent with a silane coupling agent having a chloro group, □ In a suitable liquid in which the silane coupling agent is dissolved, for example, water, or 1 such as methanol, ethanol/14, etc. The coloring agent is stirred and added to the organic solvent at room temperature or at a suitable liquid temperature. After that, the liquid and colorant are separated by a filtered centrifugation method, washed repeatedly, heated and dried in vacuum, and then used as a colorant. Color toner is produced by first mixing a binder resin and a surface-treated colorant in a mixer such as a ball mill, V-type mixer, S-type mixer, or Henshil mixer, and then,
The resulting mixture was transferred to a double-arm kneader with pressure
Goo. Knead with three rolls, etc.

This mixture is processed into a hammer mill, jiet toshir. It is manufactured by pulverizing it with a pulverizer such as a boat mill, and then classifying the resulting powder with a sieve, wind classifier, etc.

Hydrophobized colloidal silica having the same polarity as the toner, such as Aerosil R-972, 200, 100, etc., may be blended. This blending ratio is such that it does not affect the amount of charge of the toner, and is preferably 0.05 to 2 parts by weight.

A developing process to which the present invention is applied will be explained.

FIG. 1 shows a cross-sectional view of one embodiment of the developing process.

On the right side of the figure, the electrostatic image holder 5 moves in the direction of the arrow (.

The toner carrier 1 rotates in the developing section so as to move in the same direction as the surface of the holder.
The one-component non-magnetic toner 4 sent from the elastic blade 2 which is pressed onto the toner carrier).

It is applied thinly and uniformly onto the toner carrier, and the toner particles f are charged with a polarity opposite to the electrostatic image charge by friction between the toner carrier and the elastic blade and the toner particles. At this time, in the developing section, a direct current bias, an alternating current bias, or a bias in which direct current and alternating current are superimposed may be applied between the toner carrier and the surface of the electrostatic image carrier.

〔Effect of the invention〕

The first effect of the developing method using the negatively charged component non-magnetic color toner configured in this way is that the amount of frictional electrification between the toner and the elastic blade or between the toner and the toner carrier is stable. , and the amount of charge can be controlled to suit the developing system used. Therefore, development fog and toner scattering around the edge of the latent image, which have not been solved satisfactorily in the past, are eliminated, and high image density can be obtained.

Furthermore, a high-resolution image with excellent 1-spectral reflection characteristics can be obtained.

Furthermore, even when the toner is used continuously for a long period of time, it maintains its initial characteristics, allowing high-quality images to be used for a long period of time.

Furthermore, even when used under environmental conditions of high temperature, high humidity, or low temperature and low humidity, the amount of triboelectric charge of the toner is stable and hardly changes with respect to room temperature and humidity, so there is no development fog or decrease in image density, and the latent image It is possible to perform development faithfully to the image, and it also has excellent transfer efficiency.

[Fruit of invention 7I! ! Example] The basic structure and features of the present invention have been described above.
The method of the present invention will be specifically described below based on Examples. However, this does not limit the embodiments of the present invention in any way.

Parts in the examples are parts by weight.

Example 1 The above mixture was stirred at room temperature for 8 hours, filtered and washed several times, dried at 50° C. for 24 hours, and then vacuum-dried. Thereafter, it was ground into fine particles using a grinder.

In addition, the tripo charge of the above-treated colorant is -1
After premixing the above mixture, which was 3.2 μc/77, in a Henshil mixer.

The mixture was kneaded in a pressure kneader for about 1 hour.

After cooling the mixed material, it is coarsely ground in a hammer mill and then
It was pulverized in an ethomill. The pulverized product was classified using an air classification method to obtain a toner having a particle size of 5 to 25 μm.

Next, 100 parts of the toner and negatively charged colloidal silica (
0.5 parts of R-972 (manufactured by Nippon Aerosil Co., Ltd.) were mixed in a ball mill to adhere the colloidal silica to the surface of the toner. A negatively charged non-magnetic component toner with a tripo charge of minus 35.1 .mu.C/11 was used.

The above toner is applied to a commercially available copying machine (product name: RheoDry 4502).
(manufactured by Toshiba) was applied to an improved version, and an image was created using the developing method shown in FIG. As a result, a clear blue image with no development fog was obtained.

Even under high temperature and high humidity (30'' CRH851) and low temperature and low humidity (5℃RH 10%) environments, it can maintain normal temperature and humidity (
The CIE chromaticity diagram of this blue toner is x=o, 1.
It was 75y-0,224Y-25,91.

(Comparative Example 1) The same procedure as in Example 1 was performed except that an untreated colorant was used instead of the colorant treated with the silane coupling agent having a chloro group in Example 1. There were also many scatterings of positively charged latent images around the edges.

In addition, the tripo charge of this untreated colorant is plus 4.0μ.
It was c/I.

Example 2) Brilliant carmine FB3N (untreated tripocharge is +3,
The tripo charge after 3μC/92 surface treatment is -11.
Performed flJ except using 5μC/II)
When the same procedure as in 1 was carried out, a good image was obtained. still,
The average particle size of this red toner is 12
．． 6μm, tripo charge is minus 31.3μC7ICI
B chromaticity diagram is x-0,472,y-0,267,Y-1
It was 7 or 8 chi.

(Example 3) Instead of using actual m1ffl cyanine blue KBN], Seika Fast Yellow 2400 (untreated trypo charge plus 6.1 μc/I #treated trypo charge minus 9.8 μc/g) was used. Except.

When carried out in the same manner as in Example 1, good results with no development capri were obtained.

The 50% weight average particle size of this yellow toner is 13.1.
μm,) Lipo charge is minus 28.814ell eC
The IE chromaticity diagram is x-0,448,7-0,501,Y=
It was 70.6 excellent.

Furthermore, when the blue toner obtained in Example 1, the red toner obtained in Example fPU2, and the yellow toner obtained in Example 3 were combined and copied, a clear color image with extremely good color reproducibility was obtained. Furthermore, the parts that correspond to the black of the original species have been reproduced as pure black.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one example of a developing device using the developing method of the present invention. 1... Toner carrier, 2... Elastic blade, 3...
- Toner container, 4... Toner %, 5... Electrostatic image holder, 6... Rigid metal piece, 7... Side wall. Representative Patent Attorney Kensuke Chika (and 1 other person) No. 1
times

Claims (3)

[Claims] (1) An electrostatic image carrier that holds an electrostatic image on its surface and a toner carrier that carries a non-magnetic component toner on its surface are arranged at a constant interval in a developing section, and the binder resin and A negatively charged non-magnetic component color toner containing at least a coloring agent whose surface has been treated with a silane coupling agent having a chlorine group is applied to the toner carrier by an elastic blade pressed against the toner carrier to a thickness thinner than the gap. A developing method comprising applying the toner onto a toner carrier, transferring the toner to the electrostatic image carrier in a developing section, and developing the toner. (2) The developing method according to claim 1, wherein the binder resin is a styrene-acrylic copolymer having a glass transition point of 50°C or higher and a softening point of 110°C to 160°C. (3) The developing method according to claim 1, characterized in that a toner containing 0.05 to 2 parts by weight of colloidal silica is used.