JPS62184473A - Developing method - Google Patents

Abstract

PURPOSE:To obtain a clear image faithful to an original by including conductive grains in toner forming a toner layer in a developing method for moving toner on the toner layer to a latent image holding body and visualizing the latent image. CONSTITUTION:A developing machine body 2 arranged in the vicinity of the electrostatic latent image holding body 1 has a hopper 3 having its aperture part on the holding body 1 side and toner 4 is stored in the hopper 3. A toner carrying body 5 in which a part thereof is projected from the aperture part to the holding body 1 side is stored on the lower part of the hopper 3 and the carrying body 5 is rotated in the arrow direction. Toner 4 formed like a layer by a layer regulating member 7 is carried to a developing area and developed by an electric field formed between the holding body 1 and the carrying body 5. Non-magnetic toner is used for the toner 4 and conductive grains whose electric resistance value is <=10<10>OMEGAcm and grain size is <=1mum are included in the toner 4. Thus a clear image faithful to the original can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a developing method using a developer in electrophotography, electrostatic recording, etc., and more specifically to a method using a one-component developer that does not require the use of a carrier. Regarding the developing method.

[Prior Art] The method of forming an electrical latent image is well known in the art. For example, in electrophotography, a photoconductor layer is usually charged, and then the leading edge of the document is irradiated, and the irradiated area is Reduce or eliminate electrostatic charge to form an electrostatic latent image. This latent image is then developed with a developer called toner. Methods for developing latent images include, for example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade method described in U.S. Pat. Component development methods, such as the dielectric development method of U.S. Pat. No. 3,909,258, U.S. Pat. No. 3
In addition to the glue cut-down method according to the specification of No. 166432, one-component development methods using only toner are known, such as a charging development method, a jumping method, an impression method, a powder cloud method, and a fur brush method. Among these developing methods, the two-component developing method consisting of 1 to toner and chitria is an excellent developing method that can obtain relatively stable and good images. Basically, there is instability in that the electrical characteristics of the device fluctuate.

Further, the developing machine can also be significantly reduced in bulk, space, cost, etc.

In addition, a non-magnetic component toner is formed to a predetermined thickness (single layer or two layers) by a layer forming part, and at the same time a predetermined amount of electric charge is applied by frictional charging with the layer forming part to form a toner layer. In the layer forming method, it is extremely difficult to form and maintain a uniformly charged layer of toner particles when using toner particles, especially non-magnetic toner that does not contain magnetic powder. For example, when a non-magnetic component toner is used, even if good chargeability and layer formation are initially achieved, continuous use or changes in the usage environment may result in monthly wear and tear of the layer forming area. 1) The charging property changes,
In some cases, sufficient electrification may not be achieved and a uniform layer may not be formed, or the 1-ner may be extremely charged and cause agglomeration of the 1-ner on the carrier, resulting in a uniform layer formation. Formation is not carried out, and as a result, good development is not carried out, resulting in the disadvantage that an image cannot be obtained, the density of the obtained image is non-uniform, or fogging occurs.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing method which can improve the above-mentioned drawbacks and provide a clear image that is 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 which is excellent in image reproduction humidity and environmental stability such as humidity.

[Means and effects for solving the problems] As a result of extensive research, the present inventors have found that - in the component development method, 1 to 1.
The present invention was completed based on the discovery that the above-mentioned problems could be solved by containing conductive particles in the toner.

That is, in the present invention, a latent image carrier having an electrostatic latent image retained on its surface and a toner carrier carrying a toner layer having a predetermined thickness and a predetermined charge amount by a layer forming part (e) are combined in a developing part. In a developing method in which toner is placed facing each other in a contact state or in a non-contact state with a certain interval, and is visualized by moving the toner to a latent image carrier, the toner forming the toner layer contains conductive particles. This developing method is characterized by:

In the developing method of the present invention, both a magnetic toner containing magnetic powder and a non-magnetic toner containing no magnetic powder can be used as toners, or a non-magnetic toner containing no magnetic powder and the toner layer forming means may be used. The improvement effect is particularly high in the development method. This is because a uniform toner layer is formed inside the toner (in a one-component development method consisting only of non-magnetic 1-toner containing no hexagonal powder, a layer forming part (Δ) is formed on the electrostatic latent image surface). The difficulty of transporting the toner layer, good development/transfer ill?!
- This is due to the difficulty of expressing and maintaining J.

The addition of conductive particles according to the development method of the present invention improves the formation of a uniform thin layer of toner on the toner carrier, the transportability of the toner layer, and the chargeability (repetition stability, environmental stability) of the toner. making it good.

In the case of a single-component developer that does not use a carrier, the charging efficiency of the toner is generally low, and furthermore, it is difficult to control the toner so that it always forms a good toner layer and is conveyed over a certain area on the toner carrier. However, by adding a conductive substance to the toner, these problems inherent to one-component developers (particularly non-magnetic component developers) were solved.

Although the mechanism of action of conductive substances is not always clear,
11F is believed to be due to the fact that it promotes charge exchange of toner, improves charging efficiency, prevents electrostatic aggregation, and controls toner chargeability and transportability.

Therefore, it is desired that the electrical resistivity of the conductive substance is 1010 Ωcm or less, preferably 108 Ωcm or less, and 1Q10Ωc
In the case of high resistance of tn or higher, no improvement effect is observed.

Examples of these conductive substances include metal powders such as gold, silver, copper, aluminum, iron, and nickel, metal oxides such as titanium oxide, zinc oxide, tin oxide, aluminum oxide, iron oxide, and ferrite, carbon black, Grapheye 1~
Inorganic substances such as polyacetylene, organic charge transfer complexes, organic semiconductors such as anionic or cationic polymer substances, conductors, and surface treatment with conductive substances such as silica and polymers by vapor deposition, plating, solution coating, etc. You can use the ones that have been prepared. Further, it is also possible to use the above-mentioned conductive materials to which one kind of impurity is added or the electrical resistance value of which is controlled. Note that the above-mentioned conductive substances can be used alone or in combination.

The conductive substance is contained by being added inside (internally added) or externally added to the toner.

Furthermore, it is desirable to use these conductive substances in particles with a particle size of 1 μm or less, preferably 0.3 μm or less and 0.01 μm or more. It is effective to have a conductive substance present.

Regardless of whether it is added internally or externally, if the conductive substance is added excessively, the electrical resistivity of the 1 to 3 toners will decrease, and development, transferability, etc. will not be adversely affected. The amount of the conductive substance added depends on the specific gravity, particle size, etc. of the substance, so it cannot be absolutely specified, but in the case of internal addition, it is about 1% by weight to about 30% by weight, preferably about 3% by weight. % to about 10% by weight, in the case of external additions,
From about 0.01% to about 10% by weight, preferably about 0.01% by weight.
1% to about 5% by weight, the conductive material does not form a continuous layer, and the electrical resistivity of the toner is about 1014 Ωm.
It is important to add so as to achieve the above.

When these conductive substances are externally added to the toner, they may not only be simply added and mixed externally, but may also be used by being fixed to the toner particle surface using means such as hot air or a solvent.

If the particle size of the conductive substance is approximately 1 μm or more, it often deteriorates the image quality, whereas if the particle size is 0.01 μm or less, the effect tends to be smaller, probably because it is hidden by the unevenness of the toner surface. .

Since the conductive substance used in the present invention is in powder form, its electrical resistivity varies depending on the measurement conditions, etc. However, the electrical resistivity of the conductive substance specified in this specification can be measured by the following method. This is what I did.

That is, measurements were taken with a Teflon cylinder having a lower electrode with a diameter of 10 m filled with a conductive substance, an upper electrode with a diameter of 10 nwn placed thereon, and a load of 1 kg applied. At this time, the electric field applied between the upper and lower electrodes varies depending on the electrical resistivity of the conductive material, which is 106 Ωcm.
For those above, 103 V/cm was determined from the current value at the time of application, and when it was 106 Ωcm or less, it was measured using the tester method.

Furthermore, the particle size of the present conductive substance was measured using a centrifugal sedimentation method, and this value almost coincides with that confirmed using a scanning electron microscope.

As the binder resin component 1 to no used in the developing method of the present invention, various resin materials conventionally known as binder resins such as 1 to no for electrophotography are used. For example, styrene, vinyltoluene, α-methylstyrene, chlorstyrene,
Styrene and its derivatives such as aminostyrene, homopolymers and copolymers of substituted products, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylic acid, methyl acrylate,
Edyl acrylate, butyl acrylate, 2-
Acrylic acid esters such as ethylhexyl acrylate, acrylic acid, dienes such as butadiene and isoprene, acrylonitrile, vinyl ethers, maleic acid and Nisder maleate, maleic anhydride, vinyl chloride, vinyl acetate, etc. Polymers alone or copolymers with other monomers, olefin-based homopolymers or copolymers such as ethylene and propylene, polyesters, polyamides, polyurethanes, epoxy resins, polycarbonates,
Silicone resins, fluororesins, phenolic resins, petroleum resins, rosins and derivatives, synthetic and natural waxy substances, and the like can be used alone or in a mixed form.

When a copolymer is used as a binder resin, in addition to a random copolymer, the copolymer may be an alternating copolymer, a copolymer from Graph 1, a block copolymer, or a mutual/hidden copolymer depending on the application. The copolymerization mode, such as car coalescence, is appropriately selected and used. Also 2
When using a mixture of more than one type of binder resin component, in addition to mechanical mixing such as melt mixing, solution mixing, and supermulsion mixing, the mixture may be performed by copolymerization, multistage polymerization, etc. during the production of the binder resin component. good. The latter is particularly desirable when two or more components are mixed homogeneously.

As the colorant component of the toner, known dyes can be used. For example, carbon black, magnetite,
Nigrosine dye, aniline blue, chrome yellow, ultramarine blue, methylene blue chloride, phthalocyanine blue, disazo yellow, etc. can be used.

Furthermore, if it is necessary to control the chargeability of the toner, a known charge control agent can be used as appropriate. For example, negative charge control agents include metal-containing total chelates such as metal-containing dyes, acidic or electron-withdrawing organic substances, and positive charge control agents such as nigrosine, quaternary ammonium salts, and other basic electron There are donor organic substances. In addition, an inorganic substance such as a metal oxide or an inorganic substance whose surface has been treated with the above-mentioned organic substance may be used.

Furthermore, when providing a platform to control charging with the binder resin component itself, and when imparting positive chargeability, electron-donating single d components such as dimethylamine ethyl methacrylate, diethylaminoethyl methacrylate, 2-vinylpyridine, and 4-vinylpyridine are used. A binder resin containing the following can be used. When using the above-mentioned monomer components, the amine portion may be converted into a quaternary ammonium salt.

In addition, negative chargeability is added to the binder resin component (in the case of using 4, electron-withdrawing monomers such as methacrylic acid, acrylic acid, cinnamic acid, maleic anhydride, vinyl sulfonic acid, fluorine-containing acrylate, and fluorine-containing methacrylate) are used. A binder resin containing an m-form component may be used. When using an acidic monomer, a counter cation may be added to form a salt M j'A.

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

In order to improve the above-mentioned electrical properties and storage stability, including the powder fluidity of the developer, or to prevent toner filming on the photoconductor or to improve the cleaning properties of the toner [1] External additives may also be used as targets. These external additives include long chain fatty acids such as stearic acid, their esters, amides, metal salts, fine powders such as tin oxide, graphite fluoride, silicon carbide, boron nitride, silica, molybdenum oxide, cerium oxide, etc. system resin, fine powder of acrylic resin, polycyclic 'yJ aromatic compound,
Wax-like substances, crosslinked or non-crosslinked resin powders, etc. can be used. Critical surface tension 3 Q d V n/c
If the surface energy is less than m or the friction coefficient is 0,
．． Solid particles with a clear surface of 1 or less, or particles that are non-adhesive and have some abrasive properties, are particularly desirable for improving fluidity and preventing filming.

If further necessary, a treatment may be performed to harden the surface of the toner particles by applying these external additives to the surface of the toner particles using hot air or the like.

FIG. 1 shows a sectional view of an embodiment of the developing method of 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. toner 4
A toner carrier 5 is accommodated in the lower part of the hopper 3, and a toner carrier 5 is partially protruded from the opening toward the electrostatic latent image carrier. The toner carrier 5 is made of a roll, a belt, or the like having a smooth or moderately uneven surface, and is rotated, for example, in the direction of the arrow by a drive system (not shown).

Further, if necessary, a bias power supply 6 applies a DC and/or AC bias voltage.

In addition, in the toner carrier 1.8 body 5, a mechanical layer regulating part is set to control the IJ to uniformly apply toner particles to the Lli layer or two layers. be done. Layer regulation part 4・A
7 is 1 held by a blade, roll, brush, or magnet
It is made of hexagonal particles, etc., and in addition to controlling the layer, a charge can be applied by contact with the toner 4, rubbing, etc.

In this case, it is preferable to use a material 1 of the layer regulating member 7 that is located at a position appropriately away from the toner 4 on the electrification series. A DC and/or AC power source is connected to the layer regulating member 7 as required, so that an electric field is generated between the toner carrier 5 and the layer regulating member 7. This electric field transmits minute vibrations to the toner 4 sandwiched between the toner carrier 5 and the layer regulating member 7, thereby preventing the fluidity of the toner from decreasing. In addition to being advantageous in forming a thin layer 1, it is also advantageous in that it can exert an amplification effect or an electric charge injection effect when a charge is applied by contact or friction. The toner 4 formed into an ultra-thin layer by the layer regulating portion 4Δ7 is carried and conveyed to the carrier 5 by electrostatic attraction such as mirror image force and polarization force and/or van der Waals force, and is developed. It reaches the area and is opposed to the electrostatic latent image holding member 1 in a state of contact or in a state of non-contact with a small distance therebetween.

In this way, the toner 4 is generated by the electrostatic latent image and the electric field formed between the electrostatic latent image carrier 1 and the 1-S carrier 5 by the DC and σ/or AC bias voltages applied as necessary. , LIi layer: Shishi < is developed according to the electrostatic latent image pattern ('J@L) in a controlled state into two uniform ultra-thin layers.

Although the present invention has been described above with respect to a method for developing an electrostatic latent image, the method of the present invention can also be applied, if necessary, to a method for developing a non-electrostatic latent image in direct response to a C input 7J electrical signal. It is also possible to cover the application.

[Examples] The present invention will be explained below with reference to Examples and Comparative Examples.
Of course, the present invention is not limited to these examples.

Example 1 Number average molecular field approximately 15,000. Styrene Z n-butyl methacrylate copolymer with a 1,000-h average molecular weight of about 40,000 (composition ratio 70/30) 90 ffjm parts carbon black 91 ft, and 1 small part of total flex dye were mixed, and melt-kneaded using a roll mill. Coarse grinding with a hammer mill,
Fine pulverization was carried out using an air jet method, and after further classification, a toner having an average particle size of 12 μ7n was obtained.

To the above toner, hydrophobic silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) was added at 1.0% and antimony-doped tin oxide (particle size: 0.3μrrt, electrical resistivity: about 10Ωc).
M > 2.0% by weight was added and stirred with a Hatake'm mixer to prepare a developer.

As shown in FIG. 1, during development, the carrier 5 has carbon black dispersed in the phenolic resin. The layer regulating member 7 is made of stainless steel, and the blade with a thickness of 0.1 mm is coated with modified silicone rubber to a thickness of 1 ntm. The layer regulating member 7 was brought into contact with the carrier 5 at a pressure of about 1 to 51/cm.

The developing device configured in this way was manufactured by Fuji Xerox Co., Ltd.
, F X 2300 i! j. It was placed in a manufacturing machine and close-up development was performed in the with mode.

The developing conditions at this time were such that the distance between the carrier and the photoreceptor was 300 mm.
'rn, the peripheral speed of the carrier was set to 100a+r/sec, and the DC component was 300V as the developing bias.

An AC component of 1.8 KV and 2.5 KHz was applied. When development was carried out using the toner of the present invention under the conditions -F, a clear image with excellent resolution was obtained.

The above characteristics were maintained even in repeated reproduction of 10,000 images in varying environments, and stable image quality was obtained. Further, there was almost no change in the toner layer forming property and charging property during this running, and no toner of opposite polarity was generated, and a good image without unevenness could be obtained.

Example 2 In Example 1, titanium oxide (particle size: 0.03 μrn, electrical resistivity: about 1) was used instead of antimony-doped tin oxide.
A toner having the same composition as in Example 1 was produced except that 0.5 weight M part (0.09 Ωcm) was used. When evaluation was performed in the same manner as in Example 1, it was possible to obtain clear and good images with no fogging, regardless of the environment or changes over time.

Example 3 Number average molecular weight approximately 2000. Using 93 parts by weight of a polyester resin having a weight average molecular weight of about 9,000 and 7 parts of carbon black, a 1 to 1 to 1-gner having an average particle size of 12 .mu.7 nm was obtained in the same manner as in Example 1. Hydrophobic silica (R
-972) 0.7% carbon black (particle size 0
．． 02μ7n, electrical resistivity 10ΩCa1l or less) 0.5
The mixture was stirred at high speed (high-speed mixing) to prepare a developer. When this developer was evaluated under the same conditions as in Example 1, clear images without fogging were obtained. Furthermore, repeatability including environmental changes was stable.

Comparative Example 1 A developer was prepared in Example 1 without adding tin oxide. When this developer was evaluated under the same conditions as in Example 1, a clear image was initially obtained, but uneven image density was observed in a low temperature and low humidity environment. Furthermore, in repeated tests 1 and 2, a decrease in image density occurred.

Comparative Example 2 A developer was prepared in Example 3 without adding carbon black. When this developer was placed in a developing machine and subjected to the h.1' rating in the same manner as in Example 3, unevenness and toner spillage occurred in Toner 1. Furthermore, when the chargeability of the toner was evaluated, it was found that the toner had a broad charge distribution that included a considerable amount of toner of opposite polarity.

[Effects of the Invention] The present invention provides a one-component developing method in which a toner contains conductive particles, and provides a method for producing a one-component developing method in which a toner contains conductive particles, which provides a clear image that is faithful to the original, and has excellent repeat stability in image reproduction. It is characterized by excellent environmental stability regardless of changes in temperature, humidity, etc., and exhibits particularly impressive effects in non-magnetic component imaging methods.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of the developing process used in the present invention. Code in the figure: 1... D latent image holder: 2... Developing machine: 3...
・Hopper; 4. What Henner: 5.. Toner carrier; 6.. Bias power supply; 7.. Layer control shrine;
8...Power supply; 9...Electrostatic latent image. Figure 1

Claims (1)

[Scope of Claims] 1) A latent image carrier holding an electrostatic latent image on its surface and a toner carrying member carrying a toner layer having a predetermined thickness and a predetermined charge amount by a layer forming member in a developing section. Arranged facing each other in contact or with a certain distance in a non-contact state,
A developing method for forming a visible image by transferring the toner in the toner layer to a latent image holding member, wherein the toner forming the toner layer contains conductive particles. 2) The developing method according to claim 1, wherein the toner is a non-magnetic toner. 3) The developing method according to claim 1, wherein the electrical resistance value of the conductive particles is 10^1^0 Ωcm or less. 4) The developing method according to claim 1, wherein the conductive particles have a particle size of 1 μm or less.