JPS59197064A - Applying method - Google Patents

Abstract

PURPOSE:To form a stable and uniform developer thin layer even in many continuous developments by equalizing polarities of respective triboelectricity of a developer holding member for a toner and that for magnetic particles. CONSTITUTION:When a sleeve 2 is rotated, coated magnetic particles and a nonmagnetic developer are agitated and mixed while keeping a magnetic brush 8 as it is. In the magnetic blade side of a vessel 3 in this state, the mixture of the developer and nonmagnetic particles is prevented from moving by a blade 6 and rises and is moved circularly in the direction of an arrow (c). The nonmagnetic developer is triboelectrified by the sleeve 2 or coated magnetic particles because of mixing with coated magnetic particles. The triboelectrified developer is applied uniformly thinly onto the surface of the sleeve 2 with the magnetic brush 8, which is formed near the magnetic blade 6, by an image force and reaches a position facing a photosensitive drum. In this method, magnetic particles covered with a resin having the triboelectricity of the same polarity as the nonmagnetic developer are used to adjust physical properties of said developer, and a good application state is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method for developing a static latent image using a non-magnetic developer.

Conventionally, various types of dry-component developing devices have been proposed and put into practical use. However, in any of the development methods, it is extremely difficult to form a thin layer of dry component developer, and for this reason, a developing device has been constructed by forming a relatively thick layer.

However, as improvements in the clarity and resolution of developed images are currently being sought, it is essential to develop a method for forming a thin layer of a dry component developer and an apparatus therefor.

It has been proposed and put into practical use. However, this concerned the formation of a thin layer of magnetic developer. Magnetic developers must have a magnetic material added to them in order to have magnetism, which causes poor fixing properties when heat fixing the developed image transferred to transfer paper, and adding magnetic material to the developer itself. There are problems such as poor color reproduction during color reproduction.

For this reason, methods for forming a thin layer of non-magnetic developer include a method in which a soft bristle like beaver hair is used as a cylindrical brush and the developer is adhered to the brush, and a method in which the surface is made of fibers such as velvet is used. A method has been proposed in which the film is applied to a developed roller using a doctor blade or the like. However, when an elastic blade is used as a doctor blade for the fiber brush mentioned above, although it is possible to regulate the amount of developer, uniform application is not achieved and the fiber brush on the developing roller is simply rubbed.
Since no triboelectric charge is imparted to the developer existing between the fibers of the brush, there is a problem in that ghosts and the like are likely to occur. Further, since the device includes a non-magnetic developer, it is difficult to prevent the developer from leaking from the device.

The present invention eliminates the problems of the conventional method described above, forms the developer as a uniform thin layer on the surface of the developer holding member, provides sufficient triboelectric charging, and maintains stable and uniform development even during continuous development. The object of the present invention is to provide a novel coating method that allows the formation of a thin layer of developer. A further object of the present invention is to make it possible to prevent the non-magnetic developer from leaking out of the developing device.

The coating method of the present invention that achieves the above object includes a container for storing a non-magnetic developer and magnetic particles, a developer holding member for rotatably conveying the non-magnetic developer to a latent image carrier, and a non-magnetic developer for the container. A regulating member is disposed on the magnetic developer supply outlet side with a gap formed on the surface of the holding member, and a regulating member is arranged on the opposite side of the holding member with respect to the regulating member, and the developer in the container is disposed on the opposite side of the holding member. a magnet having at least one magnetic pole forming a magnetic brush of magnetic particles on the upstream side of the regulating member on the exit side, and forming a thin layer of non-magnetic developer on the holding member; The coating method is characterized in that the magnetic particles are covered with a coating, and the triboelectric charging properties of the toner with respect to the developer holding member and the triboelectric charging properties of the magnetic particles with respect to the developer holding member are of the same polarity.

With the method according to the present invention, development is possible in Japanese Patent Application Laid-Open No. 54-4
Not only can the advantages of so-called one-component jumping development as shown in No. 3037 be utilized, but even when a non-magnetic developer is used, it can be neatly coated on the developer carrier.

In addition, in the method of the present invention, the adhesion and releasability of the nonmagnetic developer and magnetic particles, and the triboelectricity and fluidity of the nonmagnetic developer greatly affect the coating Φ development. By using magnetic particles coated with a resin having triboelectric charging properties of the same polarity, it is possible to adjust the physical properties of the developer and achieve a good coating state.

The latent image carrier of the present invention may be a drum-shaped or belt-shaped member having a photoconductor or an insulating layer, and the magnetic poles may be magnetized with magnetic poles of the same polarity or different polarity in the axial direction of a magnetic roller. Alternatively, a plurality of rod-shaped magnets bonded onto a fixed support member may be used. Furthermore, as the rotating developer holding member, it is possible to use a sleeve made of non-magnetic metal such as aluminum fist or stainless steel brass, or a synthetic resin material, or an endless belt made of resin or metal. In order to improve the properties and charging properties, the surface may be roughened or provided with an uneven pattern, if necessary. Further, as the regulating member, a blade plate or a wall made of a magnetic material such as iron or a non-magnetic material such as aluminum, copper, or resin may be used.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows a sectional view of a developing device for explaining the developing principle to which the coating method of the present invention is applied.

In the figure, reference numeral 1 denotes an electrophotographic photosensitive drum, which holds a latent image formed by a latent image forming means (not shown), and rotates in the direction of arrow a to pass through a developing position shown in the drawing. A non-magnetic sleeve 2, which is a developer holding member for holding developer, faces the photosensitive drum 1 with a predetermined gap therebetween, and the sleeve 2 rotates in the direction of the arrow. A container 3 made of a non-magnetic material such as resin or aluminum is located above the sleeve 2 and stores a mixture of a non-magnetic developer 4 and covered magnetic particles 5. In this case, the magnetic blade 6 is screwed.

On the other hand, a magnet 7 is provided on the opposite side of the sleeve 2 to the magnetic blade 6. The mounting position of this magnet is determined by the relationship between the position of the magnetic pole and the magnetic blade 6.
In fact, by providing the magnetic pole slightly upstream of the magnetic blade 2, better results can be obtained in terms of preventing the magnetic particles from flowing out and uniformly applying the developer due to the action of the magnetic field.

In the above configuration, the covered magnetic particles 5 in the container 3 form a magnetic brush 8 due to the magnetic field generated between the S pole of the magnet 7 and the magnetic blade 6.

As the sleeve 2 rotates, the magnetic particles and the non-magnetic developer are stirred and mixed while the magnetic brush 8 is held. In this state, on the magnetic blade side of the container 3, the blade 6 prevents the mixture of developer and non-magnetic particles from moving upwards, and circulates in the direction of arrow C.

As a result, the non-magnetic developer is triboelectrically charged by the system sleeve 2 or the magnetic particles by mixing with the magnetic particles. The charged developer is uniformly and thinly applied to the surface of the sleeve 2 by mirror force by a magnetic brush 8 formed near the magnetic blade 6, and reaches a position facing the photoreceptor drum.

By the way, the covered magnetic particles 5 constituting the magnetic brush 8 do not flow out onto the sleeve 2 by setting the restraining force due to the magnetic field of the magnet 7 to be greater than the conveying force caused by the frictional force. . If there is a non-magnetic developer within the area of the magnetic brush 8, the ratio of the magnetic particles covered by the magnetic brush 8 to this developer is determined by the electrostatic charge due to the same polarity between the magnetic particles covered and the non-magnetic developer. It maintains a substantially constant value due to the repulsion force and the rotation of the sleeve 2. Thereby, even if the developer on the sleeve is consumed during development, the developer is automatically supplied to the area of the magnetic brush 8. Therefore, it is possible to always supply and apply a constant amount of developer onto the sleeve 2.

In the above principle explanation, a magnetic blade is used as the regulating member, but a non-magnetic blade or a wall made of a non-magnetic material such as resin or aluminum constituting the container can also be used as the regulating member.

However, in this case, in order to prevent the covered magnetic particles from flowing out, it is necessary to further reduce the gap between the sleeve and the regulating member when using a magnetic blade. Further, when a magnetic blade is used, it is preferable in that a magnetic brush can be stably formed at the exit portion of the developer due to the magnetic field between the blade and the magnetic pole.

By the way, in the developing device shown in FIG. 1, since the developer is a non-magnetic developer, there may be a problem that it tends to leak from the region d on the side where the sleeve 2 enters the container 3.

In order to prevent the developer from leaking from the area d, a magnetic brush may be formed between the sleeve and the container on the side where the sleeve enters the container.

The coated magnetic particles used in the present invention include, for example, magnetic particles coated with surface oxidized or unoxidized metals such as iron nickel, cobalt, manganese, chromium, rare earths, and their alloys or oxides. can be used. The shape of these magnetic particles may be spherical, flat, acicular, porous, or any other shape.

As a method for coating the magnetic particle surface with a resin so that it has the same polarity as the toner, for example, a coating resin, or a coating resin and a charge control agent are mixed with a solvent (toluene, xylene, M
Magnetic fine particles are mixed with this dispersion, coated on the magnetic particles by a spray dryer method, fluidized bed method, etc., dried, granulated, and sieved to remove the passed-through fraction. Examples include a method of using as coated magnetic particles.

When used for a positively chargeable toner, the coating resin may be a positively chargeable resin such as dimethylamine ethyl methacrylate, diethylaminoethyl methacrylate, or a copolymer of these and a styrene compound. As the positive charge control agent, nigrosine, copper phthalocyanine, quinophthalone, and various dyes and pigments exhibiting positive chargeability can be used.

When used for a negatively chargeable toner, a negatively chargeable resin such as polyvinyl chloride, polyethylene, polypropylene, α-chlorostyrene, polyester, etc. can be used as the covering resin. As the negative charge control agent, chromium chelate of tertiary-butylsalicylic acid and various dyes and pigments exhibiting negative chargeability can be used.

As the adhesive resin of the nonmagnetic developer used in the present invention, monopolymers of styrene and its substituted products such as polystyrene, polyP-chlorostyrene, and polyvinyltoluene; styrene-P-chlorostyrene copolymers, styrene monopolymers, etc. Pyrene copolymer, styrene-vinyltoluene copolymer,
Styrene-vinylnaphthalene copolymer, -styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-acrylic-aminoacrylic copolymer, styrene-aminoacrylic copolymer, styrene-d
Methyl chlormethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinylethyl ether copolymer,
Styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Styrenic copolymers such as polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, Terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes, etc. can be used alone or in combination.

In the non-magnetic developer of the present invention, any suitable pigment or dye can be used as a colorant.

For example, there are known dyes and pigments such as carbon black, iron black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

In addition, as a charge control agent, amino compounds, quaternary ammonium compounds, organic dyes, especially basic dyes and their salts, benzyldimethyl-hexadecyl ammonium chloride, decyl-trimethylammonium chloride, nigrosine base, nigrosine hydrochloride, safranin,
Also, crystal violet, metal-containing dyes, salicylic acid metal-containing compounds, etc. may be added.

The structure of the non-magnetic developer described above may be used in a developer formed by a commonly used mixing-pulverization method, or may be used as a wall material or a core material, or both, of a microcapsule developer.

[Example-1] An example of the present invention will be described with reference to FIG. In the figure, the same members as in FIG. 1 are given the same reference numerals. In the embodiment apparatus, the photosensitive drum 1 rotates in the direction of arrow a at a circumferential speed of 60 ma/sec. 2 is an outer diameter 32H1 thickness 0.8w O stay that rotates at a circumferential speed of 66m5/sec in the direction of the arrow.
v The sleeve is made of stainless steel (SUS 3Q4), and its surface is subjected to amorphous sandblasting using Alundum abrasive grains of 600, and the roughness of the circumferential surface is 0.8 μm (Rz=).
I made it.

On the other hand, a sintered ferrite type magnet 7c is fixedly disposed inside the rotating sleeve 2, and the N pole of its first magnetic pole is connected to the line connecting the center 0 of the sleeve 2 and the tip of the blade with respect to the magnetic blade 6. It is set at an angle of 30 degrees (0 as shown).

The S pole of one of the second magnetic poles is located opposite to the iron piece 1o, which is a magnetic member provided on the sleeve entrance side of the container. The magnetic flux density on the sleeve surface of the second magnetic pole had a peak value of 650 Gauss in the presence of the iron piece 10, and 400 Gauss when the iron piece 10 was removed. At this time, the positional relationship between the second magnetic pole and the iron piece 10 is such that the width of the iron piece in the sleeve rotation direction is 0.5 mm, and the distance between the sleeve 2 and the iron piece is 1.
, set to Ornz.

The magnetic blade 6 is made of iron, and its surface is nickel plated to prevent rust. The distance between the blade 6 and the surface of the sleeve 20 was set to 200 μm.

As the non-magnetic developer 4, 10 parts of a perylene red pigment and 5 parts of a negative charge control agent (alkyl salicylate metal complex) were internally added to 100 parts of a styrene-maleic acid copolymer.
200I of negatively charged red powder with an average particle size of 10.6 μm and externally added 0.5 qb of silica was prepared.

On the other hand, the covered magnetic particles have a particle size of 70 to 100μ,
Maximum 60 emu/g031 type ferrite 100g,
Add 2 liters of polyester resin and 2 grams of alkyl salicylic acid metal complex to a solution of 200 grams of toluene.
After stirring for 0 minutes, the mixture was dried, sieved, and covered.

After thoroughly mixing the non-magnetic developer and the covered magnetic particles, they are placed in the container 3. The mixture of the non-magnetic developer and the magnetic particles contained in the container 3 has a circular movement as the magnetic particles are conveyed by the sleeve under a magnetic field. I was able to observe the condition.

In the developing device having the above configuration, a thin layer of only non-magnetic developer having a thickness of about 110 μm was formed on the surface of the sleeve 2 as the IJ-b rotated. When the charging potential of this developer layer was measured by the blow-off method, it was found to be -9
It was confirmed that the battery was uniformly charged at a potential of , 8 μC/N.

On the surface of the photosensitive drum 1 facing the sleeve 2, a charge pattern of +600 V in the dark part and +150 V in the bright part was formed as an electrostatic latent image, and the distance from the sleeve surface was set to 300 μm. Then, a frequency of 800 Hz was applied to the sleeve by power source E.

Peak-to-peak value is l, 4 KV, center value is +30
When a voltage of 0V was applied, uneven development, ghost images,
Furthermore, it was possible to obtain developed images of high quality with no defects.

Regarding the mixture in container 3, the magnetic particles covered therein were hardly consumed, and only the non-magnetic developer was consumed for development. Moreover, the developing function remained unchanged until almost all of the developer was consumed. After consuming the above developer, remove the developing device from the main body and remove the sleeve 2.
I looked at the bottom of the , and of course there were magnetic particles there.
There was almost no leakage of developer.

Example As a non-magnetic developer, styrene-acrylic copolymer 10
0 parts, 15 parts of copper-phthalocyanine pigment were internally added and 0.5% of silica was added externally, and the average particle size was 11.0 μm. Red powder 200. I prepared F.

As the magnetic particles covered, 100 g of the ferrite used in Example-1 was mixed with 20 g of diethylaminoethyl methacrylate.
In addition to 200 mJ of DMF solution of g, coated magnetic particles were prepared.

After mixing the two, they were placed in a container 3 and idle-rotated for 10 hours.
A thin layer of m thickness of non-magnetic developer was formed. When the charging potential of this developer layer was measured by a blow-off method, it was confirmed that the developer layer was uniformly charged at a potential of +11.6 μC/El.

On the surface of the photoreceptor drum 1 facing the sleeve 2, a charge pattern of dark area -6 (light area -150 V at IOV) was formed as an electrostatic latent image, and the distance from the sleeve surface was set to 300 μm. When a voltage with a frequency of 800 Hz, a peak-to-peak value of 1.4 KV, and a center value of 1,300 V was applied to the sleeve using power supply E, a high-quality, clear red color was obtained with no uneven development, no ghost images, and no blurring. I was able to obtain a developed image.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a developing device for explaining the principle of the present invention. FIG. 2 is a sectional view of a developing device used in an embodiment of the present invention. In the figure, 2 is a sleeve which is a developer holding member, 3 is a container, 4 is a non-magnetic developer, 5 is a magnetic particle, 6 is a magnetic blade which is a regulating member, 7 is a magnet, and 10 is an iron piece which is a magnetic member. show. Applicant Canon Co., Ltd.

Claims (1)

[Claims] (1) A container for storing non-magnetic developer and magnetic particles, a developer holding member for rotationally conveying the non-magnetic developer to the latent image carrier, and a "non-magnetic developer supply outlet side" of the container. A regulating member is arranged with a gap formed on the surface of this holding member, and a regulating member is arranged on the opposite side of the holding member with respect to this regulating member and is located on the developer outlet side of the container. and a magnet having at least one magnetic pole forming a magnetic brush of magnetic particles on the upstream side, and a coating method in which a thin layer of non-magnetic developer is formed on the holding member, wherein the magnetic particles are covered with a coating. A coating method characterized in that the triboelectric charging properties of the toner with respect to the developer holding member and the triboelectric charging properties of the magnetic particles with respect to the developer holding member are of the same polarity.