JPH03243956A - Toner for developing electrostatic charge image and image forming method using same - Google Patents

Abstract

PURPOSE:To inhibit the reduction of a toner to fine powder, to prevent filming on a photosensitive body and a developing sleeve and to stably maintain the triboelectric chargeability of the toner by rendering specified mechanical characteristic values. CONSTITUTION:The small angle X-ray scattering (SAXS) of a toner is measured, the average lattice length from the primary peak of the scattering is regulated to 200-5,000Angstrom and the ratio of O1S to C1S in the surface compsn. of the toner obtd. by surface analysis is regulated to 0.015-0.055. The resulting toner having specified physical surface properties is produced by mixing a binding resin such as polystyrene or a styrene-butyl methacrylate copolymer with low mol. wt. polypropylene, adding a colorant and a charge controlling agent, well kneading them with an extruder and carrying out pulverization and classification. The reduction of the toner particles to fine powder is inhibited, filming between a developing sleeve and a photosensitive body is also inhibited and a high-quality image is formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for developing electrostatic images (electrostatic latent images) formed in electrophotography, electrostatic recording, electrostatic printing, etc. The present invention relates to a dry toner and an image forming method using the same, and more particularly relates to an electrostatic image developing toner having specific surface properties and an image forming method using the same.

[Conventional technology]

Generally, in electrophotography, electrostatic recording, etc., in order to develop an electrostatic latent image formed on a latent image carrier made of a photoconductive photoreceptor or dielectric, etc., a toner supply roller such as a developing sleeve is used. Using a toner that has been made into a thin layer using a blade, etc., and appropriately charged and pulverized, the toner image is transferred to a transfer material such as paper using a developing machine, if necessary, and then fixed using heat pressure, solvent vapor, etc. and a copy is obtained.

The developing methods applied to these electrophotographic methods can be roughly divided into dry developing methods and wet developing methods.

The former is further divided into methods using a two-component developer and methods using a one-component developer. The two-component developing methods include a magnetic brush method using an iron powder carrier, a cascade method using a bead carrier, a fur brush method using fur, etc., depending on the type of carrier that transports the toner.

In addition, the -component development methods include the powder cloud method, in which toner particles are sprayed, and the contact development method, in which toner particles are brought into direct contact with the electrostatic latent image surface (contact development or toner development method). ), a jumping development method in which toner particles are not brought into direct contact with the electrostatic latent image surface, but are charged and flown toward the latent image surface by the electric field of the electrostatic latent image; There is the MagneDry method, which develops by contacting the electrolatent image surface.

In these development methods, silicone oil or the like is used as a release agent in order to improve offset properties in the fixing area, or low molecular weight polyethylene or polypropylene is mixed in to give the toner release properties. are doing. In this case, low molecular weight polyethylene or polypropylene.

Since it has poor compatibility with polystyrene used as a binder resin, phase separation occurs during crosstalk. At interfaces due to phase separation, 1 destruction occurs easily when mechanical force is applied, and the toner is pulverized. The phenomenon of toner pulverization occurs at the contact surface between the developing sleeve and the photoconductive photoreceptor.

For example, in the case of a contact development method, the pulverized toner adheres to the developing sleeve, causes a fusion phenomenon over time, and forms a film on the developing sleeve. When a filming phenomenon begins to appear on the developing sleeve, the thickness of the thinned toner layer becomes non-uniform, which causes non-uniform distribution of the amount of charge during development of the electrostatic latent image, which causes problems in development. This results in uneven toner adhesion per unit area on the sleeve, and as a result, shading also occurs on the copy, which is a serious problem in terms of image quality. The pulverization of the toner caused by the fragility of the toner particles means that they are easily pulverized by mechanical force, which is preferable from the viewpoint of toner productivity.

Therefore, in order to avoid this kind of filming phenomenon,
It is possible to use a polymer with a high molecular weight, but considering the thermal fixation of images that is usually performed in the final process of copying or printing, the fixing temperature increases and more heat is required for fixing, so it is energy-saving. This is undesirable from the viewpoint of downsizing or miniaturization of hardware equipment. Furthermore, in order to eliminate this phenomenon, it has been proposed to add a small amount of plasticizer to the toner, but there are problems such as impairing the free flow properties of the toner and contaminating the carrier etc. If the toner is not successful, and the toner is too hard, it may not be possible to mechanically grind it, or it may not be able to be sufficiently dispersed due to crosstalk.

For the reasons mentioned above, relatively low molecular weight polystyrene or styrene-butyl methacrylate copolymer, which can have appropriate hardness, has been used as a binder resin for toners. However, in the case of equipment such as laser printers that use electrophotography and are desired to be maintenance-free, conventional melt crosstalk using polymers such as styrene-butyl methacrylate copolymer cannot be used. The crosstalk between the main polymer and the low molecular weight polyethylene added to provide mold releasability is not appropriate, and phase separation forms a large domain structure in a macroscopic region on the order of microns.

Therefore, it has been found that Nil easily occurs at the interface during phase separation, and that the toner does not have sufficient hardness, and that a toner that forms a higher-order structure with high mechanical strength is required. In addition, from the viewpoint of maintenance-free development, a one-component development method is considered to be preferable to a two-component development method that uses a carrier or the like because the system is simpler. Furthermore, this type of binder resin has insufficient properties for heat fixing using a currently commonly used hot roll, and the adhesion of the toner binder resin to melted paper due to heat is not good. However, there is an offset phenomenon to the heat roller.

In addition, fluidization promoters are often used to suppress filming on the developing roller and photoreceptor and spent on the carrier. The publication describes the use of metal soap in JP-A-52-153441 and JP-A-53-147541.
In the publication, the use of fluorine-based compounds is disclosed in
No. 34 uses a nonionic surfactant.

Furthermore, Japanese Patent Application Laid-Open No. 56-62256 proposes the use of silica whose surface has been made hydrophobic.

Furthermore, Japanese Patent Application Laid-Open No. 56-66856 discloses that particles harder than the toner are embedded in the surface of the toner.
In Japanese Patent Application Laid-open No. 134651, an ion exchange resin is contained in a binder resin, and in JP-A-59-131943, oxidized polyethylene is used as a mold release agent, which is compatible with the binder resin and has a mold release effect. In Japanese Unexamined Patent Publication No. 56-197048, the inclusion of silicone oil in the binder resin is disclosed in Japanese Unexamined Patent Publication No. 59-22.
No. 0748 discloses that wax fine particles are externally added to toner, and JP-A No. 60-138565 discloses that carbon black is externally added to reduce the resistance of toner. No. 60186852, JP 60-186853, JP 60-1868
No. 54, JP-A-60-186855, JP-A-60-1
No. 86857, JP-A-60-111168511, JP-A-60-186860, Jikai@60-186861
No., JP-A-60-186862, JP-A-60-186
No. 863, JP-A-60-186864, JP-A-60-
No. 186865 and JP-A No. 186866/1986 disclose that polymer fine particles are externally added.
Publication No. 99164 proposes external addition of abrasives (SiC, 5iN).

[Problem to be solved by the invention]

However, just by using additives as mentioned above,
The effect of suppressing filming on the developing roller and photoreceptor and spent on the carrier is still insufficient, and it is possible to prevent filming and spent by improving the higher-order structure of the toner formed by the polymer, which is the main component of the toner. The best way is to avoid this.

Therefore, an object of the present invention is to suppress toner particles from becoming fine powder on a photoreceptor or a developing sleeve, and to prevent the toner particles from becoming fine powder on the developing sleeve and the photoreceptor due to frictional heat between the developing sleeve and the photoreceptor or between the developing sleeve and the blade. Toner for developing electrostatic charge images that suppresses filming on bodies, spent on carriers, and sticking to blades, and provides permanently good copied images with the above-mentioned suppressing effects, and image formation by a one-component development method using the same. The purpose is to provide a method.

[Means to solve the problem]

As a result of intensive research, the inventors of the present invention found that a toner having specific surface properties is suitable for the above purpose, and completed the present invention.

That is, according to one aspect of the present invention, in a toner comprising at least a binder resin and a colorant, small-angle X-ray scattering (SAX
When S) is measured, the average lattice length from the primary peak of scattering is 200-s, and the surface composition ratio 01s/C1, according to the toner surface analysis, is 0.015 to 0.
Provided is a toner for developing an electrostatic image, characterized in that the toner has a particle size of 0.055°.

Further, there is provided an image forming method using the toner described above, in an image forming method using a one-component development method in electrophotography, in which a thin layer of toner is supplied to a latent image carrier to develop a latent image. Ru.

Note that the small-angle X-ray scattering (SAXS) of toner referred to herein refers to the following phenomenon, and its measurement is performed as follows. In other words, if there are microscopic particles of about 10 to 1,000 particles or an area with a non-uniform density corresponding to this size, diffuse scattering (central scattering) occurs in the direction of the incident beam.
occurs. This central scattering is unrelated to the internal structure of a single particle, and the smaller the particle, the more it spreads out.

This scattering exists regardless of whether the material is crystalline or amorphous, and is observed in a scattering angle range of about 0 to 5 degrees. In order to measure the average lattice length specified in the present invention, it is preferable to use an X-ray generator with a large allowable load, and use a small-angle X-ray scattering device and a Clatsky slit. By using a Kuratuki slit, the resolution is 10,000 people. X
As the line diffraction device body, for example, R manufactured by Rigaku Denki Co., Ltd.
INT-1500 (18,0kV) is suitable.

In addition, X-ray electron spectroscopy (ESCA) is used to measure the structural composition ratio of the toner surface through toner surface analysis.
ctron 5pectroscopy for Ch
chemical analysis S) was used. This device is the most suitable method for quantitative WA observation of the chemical structure of the surface of an organic substance, and is a surface analysis method that has been frequently used in recent years. The information obtained here is that peaks from various elements are obtained by differences in binding energy, and although broad peaks are detected as measured values, waveform separation is performed by computer processing, and peaks due to a certain element are detected. is separated into many bond state peaks. Quantification by elemental analysis is also possible, and the ratio between CXS and 011 peaks can be measured. In this measurement, the toner powder was fixed with double-sided tape, and the measurement was performed as it was without sputtering the toner surface.

The toner having specific surface properties of the present invention can be produced by mixing low molecular weight polypropylene, if desired, with a binder resin such as polystyrene or styrene-butyl methacrylate copolymer, and adding a colorant and, if desired, a charge control agent thereto. It is obtained by thoroughly kneading with an extruder, followed by pulverization and classification.

When an image is formed using a one-component development method using the toner having the above-mentioned surface properties of the present invention, it is finely powdered and adheres to the developing sleeve or photoreceptor without adding a fluidizing agent or abrasive. No toner is observed and no filming occurs.

If the average lattice length from the primary peak of scattering in the toner is less than 200, it becomes difficult for the release agent such as low molecular weight polypropylene to be eluted from the toner surface, and an offset phenomenon occurs during fixing. On the contrary, 2,00
If there are more than 0 people, low molecular weight polypropylene etc. will be very easily eluted, and a phenomenon of toner filming on the developing roller surface, photoreceptor (latent image carrier) surface, etc. will be observed.

Furthermore, if the surface composition ratio 01s/C,8 is less than 0.015, poor development is likely to occur. On the contrary, 0.05
If it exceeds 5, the adhesion force onto the photoreceptor is too strong, resulting in poor transfer rate and poor cleaning.

The binder resin used in the toner of the present invention includes:
The binder resin is not limited to the above-mentioned polystyrene and styrene-butyl methacrylate copolymer, but binder resins that have been conventionally used as binder resins for toners can be used. Specifically, the monomer of the binder resin includes styrene, 0-methylstyrene, ■-methylstyrene, p-methylstyrene,
p-ethylstyrene, 2,4-dimethylstyrene, p-
n-butylstyrene.

p-tert-butylstyrene, p-n-hexylstyrene.

p-n-octylstyrene, p-n-nonylstyrene,
p-n-decylstyrene, p-n-dodecylstyrene,
Styrenes such as p-methoxystyrene, p-phenylstyrene, P-chlorostyrene, and 3,4-dichlorostyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride, vinylidene chloride, Vinyl halides such as vinyl bromine and vinyl fluoride; vinyl esters such as vinyl acetate and vinyl propionate; methyl acrylate, ethyl acrylate,
n-butyl acrylate, methyl methacrylate, ethyl methacrylate.

α-methylene aliphatic monocarboxylic acid esters such as n-butyl methacrylate; vinyl ethers such as vinyl methyl ether; vinyl ketones such as vinyl methyl ketone; N-vinylpyrrole, N-vinylcarbazole, tovinylindole, N Examples include N-vinyl compounds such as -vinylpyrrolidone. These monomers are
They can be used alone or in combination of two or more types.

In addition, monomers for forming the single polycondensation type resin include:
Ethylene glycol, triethylene glycol, 1,2
- Polyhydric alcohols such as propylene glycol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A; polyhydric amines such as ethylenediamine, tetramethylenediamine, piperazine; maleic acid, fumar acid.

Examples include mesaconic acid, citraconic acid, adipic acid, malonic acid, and their acid anhydrides or esters with lower alcohols.

Furthermore, the toner of the present invention contains synthetic waxes such as low molecular weight polyethylene and polypropylene, as well as vegetable waxes such as candelilla wax, carnauba wax, rice wax, wood wax, and jojoba oil, in order to provide release properties. Contains animal-based waxes such as beeswax, lanolin, and spermaceti; mineral-based waxes such as montan wax and osikelite; oil-based waxes such as hydrogenated castor oil, hydroxystearic acid, fatty acid amides, and phenolic fatty acid esters. can do.

Note that the toner of the present invention contains a colorant and, if desired, may contain a charge control agent and the like. Conventionally known toner colorants and charge control agents are applied to these, and specifically, metal chelate dyes such as carbon black, oil black, nigrosine dyes, metal-containing dyes,
Aniline dye, Calco oil blue, Chrome yellow,
Examples include ultramarine blue, methylene blue chloride, phthalocyanine blue, rose bengal, and other dyes or pigments.

The toner of the present invention is particularly useful for image formation using a one-component development method in electrophotography, and the image forming method of the present invention will be described next.

The image forming method of the present invention is an image forming method using a one-component development method in electrophotography in which a thin layer of toner is supplied to a latent image carrier to develop a latent image. It is characterized by using Note that toner thinning is usually achieved by including a toner conveying member, a toner layer thickness regulating member, and a toner supplying member, and in which the toner supplying member and toner conveying member and the toner layer thickness regulating member and toner conveying member are in contact with each other. It is carried out using the same equipment.

The image forming method of the present invention will be explained in more detail with reference to the drawings.

The drawing is a schematic cross-sectional view of an example of a developing device using a non-magnetic component toner useful for carrying out the method of the invention. In drawing 0, the toner 6 of the invention contained in a toner tank 7 is stirred. The toner is forcibly brought to the toner supply member (sponge roller) 4 by the vane (toner supply auxiliary member) 5, and the toner is supplied to the toner supply member 4. When the toner supply member 4 rotates in the direction of the arrow, the toner taken into the toner supply member 4 is transported to the toner transport member 2, where it is rubbed, electrostatically or physically handled, and the toner is transported. The member 2 rotates strongly in the direction of the arrow, and a uniform thin layer of toner is formed by the toner layer thickness regulating member (elastic blade) 3 made of steel, and is charged by friction. Thereafter, the toner is transported to the surface of the electrostatic latent image carrier 1 that is in contact with or in close proximity to the toner transport member 2, and the latent image is developed. The electrostatic latent image is created by charging the organic photoreceptor with a negative DC charge of 800 cm and then exposing it to light to form a latent image, which is then developed. Note that developing devices suitable for the toner of the present invention are not limited to those described above.

In such an image forming method using a one-component development method in electrophotography, if finely powdered toner adheres to the developing sleeve and forms a film, it will greatly affect the ability to form a uniform thin layer of toner. The toner is suppressed from being pulverized on the photoconductive photoreceptor or developing sleeve, and its formation is suppressed from forming on the imaging sleeve or photoconductive photoreceptor, so that the toner is uniformly formed in a single layer on the developing sleeve. By the method of the present invention, for a long period of time,
High quality images can be obtained.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts represent parts by weight.

Example 1 Polystyrene 15 parts Polyester resin 30 parts Low molecular weight polypropylene 5 parts Carbon black
5 parts A mixture having the above composition was kneaded using an extruder, then pulverized and classified to obtain a toner having an average particle size of 10 IIm. Small-angle X-ray scattering (SAXS) of the obtained toner
As a result of the measurement, the average lattice length from the primary peak of scattering was 700, and the surface composition ratio according to the toner surface analysis was 01. /C engineering was 0.035.

When the obtained toner was used to form an image using a developing device as shown in the drawing, a good image was obtained, and the image did not change even after running 100,000 copies.

Further, when the charge amount of the toner was measured by a suction method, the initial charge amount was -10.8 μC/g, and the charge amount after running 100,000 sheets was -10.7 μC/g, which was almost unchanged from the initial value. Incidentally, no filming due to adhesion and melting of toner was observed on the surface of the photoconductive photoreceptor or the surface of the developing sleeve.

Example 2 Polycarbonate 10 parts Polystyrene 65 parts Polymethacrylic acid
10 parts Polyn-butyl methacrylate 100 parts Low molecular weight polypropylene 5
1 part carbon black 6 parts The mixture having the above composition was kneaded using an extruder, and then pulverized and classified to obtain a toner having an average particle diameter of ttm. As a result of small-angle X-ray scattering (SAXS) measurement of the obtained toner, the average lattice length from the primary peak of scattering was 1,500 particles, and the surface composition ratio Chi/C was determined by surface analysis of the toner.
1m was 0.050.

When an image was produced using the obtained toner in the same manner as in Example 1, a good image was obtained, and the image remained unchanged even after running 80,000 sheets.

Furthermore, when the toner charge amount was measured using a suction method, the initial charge amount was -10.2 μC/g, and the charge amount after running 80,000 sheets was -10.3 μC/g, which was almost unchanged from the initial value. Ta. Incidentally, no filming due to adhesion and melting of toner was observed on the surface of the photoconductive photoreceptor or the surface of the developing sleeve.

Example 3 Polyphenylene ether 45 parts Polystyrene 30 parts Polymethacrylic acid
5 parts poly-butyl methacrylate
10 parts 2-ethylhexyl polyacrylate 5 parts low molecular weight polypropylene 5 parts G-tert
- Butyrusalicylic acid zinc salt 6 parts Carbon black 10 parts The mixture having the above composition was kneaded using an extruder, and then pulverized and classified to obtain a toner having an average particle size of 11M. As a result of small-angle X-ray scattering (SAXS) measurement of the obtained toner, the average lattice length from the primary peak of scattering was 1,050, and the surface composition ratio O/Cxs according to the surface analysis of the toner was 0.02
It was 5.

When an image was produced using the obtained toner in the same manner as in Example 1, a good image was obtained, and the image did not change even after running 200,000 copies.

Furthermore, when the toner charge amount was measured using a suction method, the initial charge amount was -13.7 μC/g, and the charge amount after running 200,000 sheets was -13.5 μC/g, which was almost unchanged from the initial value. Ta. Incidentally, no filming due to adhesion and melting of toner was observed on the surface of the photoconductive photoreceptor or the surface of the developing sleeve.

Comparative Example A mixture having the same composition as in Example 1 was melt-kneaded using two rolls, and then pulverized and classified to obtain an average particle size of 11-
I got the toner. Small-angle X-ray scattering (SA) of the obtained toner
As a result of measuring XS), the average lattice length from the primary peak of scattering was 5,500, and the surface composition ratio according to toner surface analysis was 01. /C1j was o, oos.

When an image was produced using the obtained toner in the same manner as in Example 1, no good image was obtained. The image got even worse after 10,000 runs.

In addition, when the amount of charge on the toner was measured using the suction method, the initial charge amount was -8.7 μC/g, and the charge amount after running 10,000 sheets changed by about 6 μC/g to -2.3 μC/g. . Note that there is a noticeable filming of adhered and melted toner on the surface of the photoconductive photoreceptor and developing sleeve.
was observed.

〔Effect of the invention〕

Since the toner for developing electrostatic images of claim (1) has specific mechanical property values, when an image is formed using the toner, fine powder of the toner is formed on the photoconductive photoreceptor or the developing sleeve. As a result, filming in which toner adheres and melts does not occur on the photoconductive photoreceptor or developing sleeve. Further, the adhered toner does not become a thin layer and a film is formed, and furthermore, the frictional charging property between the toner and the developing sleeve etc. is maintained stably.

Therefore, according to the image forming method of claim (2), a state in which the toner is uniformly formed into a single layer is formed on the developing sleeve, and development on the photoconductive photoreceptor is performed uniformly, and over a long period of time. It is possible to stably obtain high-quality images.

[Brief explanation of drawings]

The drawing is a schematic sectional view showing an example of a developing device using the non-magnetic component toner of the present invention useful for carrying out the method of the present invention. 1... Electrostatic latent image carrier, 2... Toner transport member, 3
... Toner layer thickness regulating member, 4... Toner supply member,
5... Stirring blade, 6... Toner, 7... Toner tank.

Claims (2)

[Claims] (1) In a toner consisting of at least a binder resin and a colorant, when measuring small-angle X-ray scattering (SAXS) of the toner, the average lattice length from the primary peak of scattering is 200 to 5,000.
0 Å, and a surface composition ratio O_1_3/C_1_3 of 0.015 to 0.055 as determined by surface analysis of the toner. (2) An image forming method using a one-component development method in electrophotography, in which a thin layer of toner is supplied to a latent image carrier to develop a latent image, characterized by using the toner according to claim (1). image forming method.