JP2002072765A - Image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording apparatus which can stably transfer a toner image to a transferred body with high transfer efficiency. SOLUTION: This apparatus is equipped with image carriers 1K, 1Y, 1M, and 1C which have photosensitive body layers on their surfaces, electrostatic chargers 2K, 2Y, 2M, and 2C which electrostatically and uniformly charge the image carriers, image writing devices 3K, 3Y, 3M, and 3C which forms electrostatic latent images by irradiating the uniformly charged image carriers with image light, four developing devices 4K, 4Y, 4M, and 4C which contain developers of four colors K, Y, M, and C, an intermediate transfer body 5a which comes into contact with the image carriers 1K and 1Y, an intermediate transfer body 5b which comes into contact with the image carriers 1M and 1C, an intermediate transfer body 6 which comes into contact with both the intermediate transfer bodies 5a and 5b, a transfer roller 7 which is put over the intermediate transfer body 6 to transfer a transferred toner image onto a recording paper P, a fixing device 9 which fixes the toner image on the recording paper P, and a particulate sticking device 100 which uniformly give particulates to the surfaces of the intermediate transfer bodies 5a, 5b, and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image recording apparatus for recording an image by a system such as electrophotographic recording, electrostatic recording, ionography, and magnetography.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus used for, for example, a laser printer or a copying machine of an electrophotographic recording system, a toner image formed on an image carrier such as a photosensitive drum is transferred via an intermediate transfer member. 2. Description of the Related Art There is known an intermediate transfer type image recording apparatus that transfers an image onto a recording medium such as paper.

[0003] Such an intermediate transfer type image recording apparatus is widely used especially as an image recording apparatus for recording a color image. For example, black (K) and yellow (Y) formed on an image carrier are used. , Magenta (M), and cyan (C) toner images are sequentially primary-transferred onto the intermediate transfer body and superimposed, and the K, Y, M, and C toner images superimposed on the intermediate transfer body are A color image is obtained by collectively performing secondary transfer from the intermediate transfer body to a recording medium and then fixing.

In the intermediate transfer type image recording apparatus, compared with an image recording apparatus of a type in which image data is directly transferred from an image carrier to a recording medium, the image recording apparatus is caused by a recording medium such as transfer failure due to a difference in characteristics of the recording medium. There are advantages that various problems can be solved, and this is a major reason for employing the intermediate transfer method in an image recording apparatus for recording a color image. Of course, not only for color images, but also for black-and-white images, the intermediate transfer member is used for the purpose of improving various problems caused by the recording medium. The intermediate transfer member is widely used for the purpose of improving image quality of toner images and toner images.

On the other hand, recently, from the viewpoint of global environmental protection, a cleanerless image recording apparatus which does not require a cleaner and does not generate waste toner has been proposed for ecological measures. For example, Japanese Patent Application Laid-Open No. S59-133573 discloses an image recording apparatus in which a toner remaining on a background portion after transferring a toner image is transferred to a developing roll to collect the residual toner without using a cleaning device. Is disclosed. As a practical example of this type of image recording device, a cleaner-less laser printer based on the concept of “simultaneous development cleaning method” was developed in “Japan Hardcopy '89” hosted by the Society of Electrophotography held in July 1989. It has been reported that they did.

[0006]

However, in such an image recording apparatus of the simultaneous development and cleaning system, paper dust and the like mixed in the toner at the time of transfer or the like are also collected by the developing apparatus, which causes image defects. May be.

There have been reported several image transfer apparatuses of an intermediate transfer system which have been devised to solve the problem of paper dust contamination in the simultaneous cleaning system. For example, in Japanese Patent Application Laid-Open No. 5-210294, the provision of the intermediate transfer member prevents the photosensitive drum from directly contacting the recording paper P, so that paper dust does not adhere to the photosensitive drum, and There is a description that paper dust does not enter the apparatus and image defects can be prevented.
However, in this method, the transfer efficiency of the intermediate transfer member has not been improved, and untransferred toner remains on the intermediate transfer member, so a cleaner for the intermediate transfer member is required. It is inevitable that the original technical concept of an image-less image recording device is deviated.

Further, among image recording apparatuses using an intermediate transfer body, there has been proposed an image recording apparatus of a type in which a cleaner for the intermediate transfer body is not provided. For example, JP-A-8-314
No. 231 discloses an image recording apparatus in which residual toner on an intermediate transfer member is removed by transferring the toner to a transfer roller or the like to which a voltage having a reverse polarity is applied. However, in this image recording apparatus, it is necessary to provide a cleaner for removing the toner transferred to the transfer roller, and it cannot be said that the cleaner-less image recording apparatus essentially does not require a cleaner and does not generate waste toner.

Therefore, the present inventors have proposed, for example, Japanese Patent Application Laid-Open
As disclosed in Japanese Patent Publication No. 212010, there is proposed an image recording apparatus in which a cleaner for an intermediate transfer body is essentially unnecessary and no waste toner is generated. In this image recording apparatus, a substantially uniform fine particle layer is formed on the image carrier and the intermediate transfer body, and the toner image is formed / transferred on the fine particle layer, so that the transfer efficiency of the toner image is remarkably improved. In addition, a cleaner can be eliminated.

However, at this time, in order to stably achieve a transfer efficiency of almost 100%, the state of fine particles attached on the image carrier and the intermediate transfer member must be maintained in an appropriate state. It is necessary to establish an effective means for maintaining such an appropriate state of adhering fine particles.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image recording apparatus capable of stably transferring a toner image onto a transfer target with high transfer efficiency.

[0012]

An image recording apparatus according to the present invention, which achieves the above object, forms a toner image on a predetermined image carrier and transfers the toner image formed on the image carrier to a predetermined intermediate image. An image recording apparatus that records an image on a recording medium by transferring the toner image transferred on a transfer body and transferring the toner image on the intermediate transfer body to a predetermined recording medium, and fixing the toner image. Fine particles are stored in the outer shell, and fine particles attaching means for attaching the fine particles discharged from the mesh to the surface of the image carrier and / or the surface of the intermediate transfer member is provided.

Here, the fine particle adhering means preferably has a mesh outer shell formed in a roll shape.

Further, it is preferable that the fine particle adhering means includes a driving device for rotating the roll-shaped outer shell.

Further, the fine particle adhering means transfers electric charges for generating a force for attracting the fine particles housed in the outer shell to the image carrier or the intermediate transfer member, on the surface of the image carrier or the intermediate transfer member. It is also a preferred embodiment to include a means for applying a charge to the body surface.

In another preferred embodiment, the fine particle adhering means has an outer shell formed of a nylon mesh. Further, the fine particle adhering means may have a mesh of 0.1 mm or less. It is also preferable to have an outer shell formed of an open mesh.

It is also preferable that the fine particle adhering means includes a vibration device for vibrating the outer shell.

[0018]

Embodiments of the present invention will be described below.

FIG. 1 is a schematic configuration diagram showing a first embodiment of the image recording apparatus of the present invention.

The image recording apparatus 10 according to the first embodiment is an example applied to a color image recording apparatus, and includes black (K), yellow (Y), magenta (M), and cyan (C). Drum-shaped image carriers 1K, 1Y, 1M, and 1C each having a photosensitive layer on the surface corresponding to the four colors
And a charger 2K for uniformly charging each of these image carriers.
2Y, 2M, and 2C, and image writing devices 3K and 3 that irradiate the uniformly charged image carrier 1 with image light to form an electrostatic latent image.
Developing devices 4K, 4Y, 4M, and 4C containing developers of four colors of Y, 3M, and 3C, K, Y, M, and C;
A first intermediate transfer member 5a in the form of a drum which comes into contact with K and 1Y;
A drum-shaped first intermediate transfer member 5b in contact with the image carriers 1M and 1C, a drum-shaped second intermediate transfer member 6 in contact with both of the intermediate transfer members 5a and 5b, and on the second intermediate transfer member 6 The toner image superimposed and transferred on the paper guide 11
Paper P transported by the transport roller 8 along the
It has a transfer roller 7 for transferring upward, a fixing device 9 for fixing a toner image on the recording paper P, and a fine particle attaching device 100 for uniformly applying fine particles to the surfaces of the intermediate transfer bodies 5a, 5b, 6. I have.

The fine particle attaching apparatus 100 according to the present embodiment corresponds to the fine particle attaching means according to the present invention, and the recording paper P according to the present embodiment corresponds to the recording medium according to the present invention. It is.

The image carrier 1 is a function-separated type photoconductor in which a charge generation layer and a charge transport layer are sequentially laminated on a metal support such as aluminum, and has a volume resistivity of 8.5 × 10 ^15.
Ωcm. The volume resistivity was measured using a high resistivity meter Hiresta IP manufactured by Mitsubishi Chemical Corporation.

The charger 2 applies a high voltage to the electrode wires to generate corona discharge with the image carrier 1 to uniformly charge the surface of the image carrier 1.

The image writing device 3 repeatedly scans the laser beam of the light emitting element (LD) in a direction substantially perpendicular to the rotation direction of the image carrier, and the light emitting element is turned on / off based on an image signal. The image exposure is performed on the rotating image carrier 1.

The four developing devices 4 transfer toner to a latent image formed on the image carrier 1 to form a visible image (toner image).

The first intermediate transfer members 5a and 5b are made of the same material,
3mm thick aluminum pipe
A silicone rubber as an elastic layer
Form a 4mm-thick dispersion of racks,
Fluorine latex (Daikin Industries, Ltd.)
Coatings Co., Ltd. CLS-213) with a thickness of 20 μm
And baked at 250 ° C.
The diameter of the ram is 40 mm. In addition, fluorine latex
The hardness of the intermediate transfer drum after coating is AS
It is 40 degrees with a KER-C hardness tester (manufactured by Kobunshi Keiki Co., Ltd.).
The resistance value of the silicone rubber as the elastic layer is 1.3 ×
10⁷Ω and the surface layer of fluorine latex is coated.
The resistance values of the first intermediate transfer members 5a and 5b after the
1 × 10 ⁹Ω.

The measurement of the resistance value in the present embodiment was performed as follows. The intermediate transfer member and the metal roller (diameter: 40 mm) are set so that their axes are parallel to each other.
A DC power supply (a high-voltage power supply MODEL 610C manufactured by TREK) is connected to the metal core of the intermediate transfer member, and the metal roller is connected to the ground. The metal roller is driven to rotate at 10 rpm, and the intermediate transfer member is driven by the rotation. +100 V is applied to the intermediate transfer member from a DC power supply, and a voltage output from a current monitoring terminal of the DC power supply 610C is read by a recorder and converted into a current value. The value obtained by dividing the applied voltage (100 V) by the obtained current value is defined as the resistance value of the intermediate transfer member.

The second intermediate transfer member 6 is the first intermediate transfer member 5
Almost the same as a and 5b, a core of an aluminum pipe having a thickness of 3 mm is formed on a core metal having a thickness of 4 mm by dispersing carbon black in silicone rubber as an elastic layer, and a fluorine latex is formed thereon as a surface layer. (CLS-213, manufactured by Daikin Industries, Ltd.) coated at a thickness of 20 μm and fired at 280 ° C. The final intermediate transfer drum has a diameter of 40 mm. The hardness of the intermediate transfer drum after coating with fluorine latex is
It is 50 degrees with an ASKER-C hardness tester (manufactured by Kobunshi Keiki Co., Ltd.). The resistance value of the silicone rubber as the elastic layer is 1.
The resistance value of the second intermediate transfer member 6 after coating the surface layer of fluorine latex was 3.4 × 10 ⁷ Ω.
10 ¹¹ Ω.

The first intermediate transfer members 5a and 5b and the second intermediate transfer member 6 are charged with electric charges for generating a force for attracting the fine particles housed inside the fine particle attaching device 100 to the respective intermediate transfer members. There is provided a charge applying means 12 for applying to the surface of each intermediate transfer member. Charge applying means 12
Will be described later.

Each intermediate transfer member used in the present embodiment may be made of a material and configuration other than those described above.
For example, as an elastic layer other than the above, fluorine rubber, urethane rubber, styrene butadiene rubber, ethylene propylene copolymer, butadiene rubber, acrylic rubber, acrylonitrile butadiene rubber, chloroprene rubber, rubber and foams such as butyl rubber, and carbon black and A material to which a conductive filler such as a metal oxide is added can be used.

As the surface layer, silicone rubber,
Rubber such as fluoro rubber, urethane rubber, ethylene propylene rubber, foam and latex, polyester, polyethylene, polycarbonate, polyvinylidene fluoride, polypropylene, perfluoroalkoxy (P
FA), a resin such as polyamide, polyamide imide, polyetheretherketone (PEEK), ethylenetetrafluoroethylene copolymer (PTFE) or a mixture thereof, and carbon black or metal oxide as the above material. The above-mentioned elastic layer may be coated with, for example, a material to which a conductive filler is added, or may be formed into a tube-like shape.

The intermediate transfer member used in the present embodiment is not limited to the two-layer structure as described above, but may be a single layer or a structure having three or more layers. Further, other than the drum-shaped intermediate transfer body as described above, for example, a roller-shaped or belt-shaped intermediate transfer body may be used.

The transfer roller 7 is formed by forming a silicone foam layer having a skin layer on a metal cored bar, and further forming PTFE as a coat layer on the skin layer. The thickness of the coat layer is 10 μm, and the resistance value of the entire layer including the coat layer is adjusted to 10 ⁷ to 10 ⁸ Ω.

Next, the developer used in the developing devices 4K, 4Y, 4M, and 4C will be described. <Toner> As the toner, for example, a toner produced as follows can be used.

Polyester (number average molecular weight: 4300,
Weight average molecular weight: 9800, Tg = 58 ° C) 94 wt
%, Cyanine Blue 4938 (manufactured by Dainichi Seika) 6wt%
Is kneaded and pulverized to obtain colored particles having an average particle size of 7 μm. Fine particles obtained by hydrophobizing silica having an average particle diameter of 12 mm with hexamethyldisilazane (HMDS) are externally added to the colored particles at a ratio of 40% of the toner surface area to obtain a cyan toner. The charge polarity of this toner is negative. The average particle size is a value measured by a Coulter counter (manufactured by Coulter Inc.).

The coverage f (%) of the silica fine particles is represented by dt (m) of the average particle size of the toner and d
a (m), the specific gravity of the toner is ρt, the specific gravity of the silica fine particles is ρa, the weight of the silica fine particles is Wa (kg), and the weight of the toner is Wt (kg).

F (%) = ｛(√3 × dt × ρt × Wa)
/ (2 × π × da × ρa × Wt)｝ × 100 The specific gravity of the above toner is 1.0, and the specific gravity of the silica fine particles is 2.2.

Generally, the particle size of toner particles has a large effect on image quality, and the larger the particle size, the coarser the image. There is no practical problem with toner having an average particle diameter of about 20 μm, but in order to increase the resolution of fine lines, the average particle diameter is 10 μm.
It is desirable to use a toner of μm or less. However, as the toner diameter decreases, the physical adhesive force acting between the toner and the carrier becomes dominant, and the developability decreases.
Further, when the toner diameter is small, aggregation of the toner is likely to occur, which causes a problem in handling. From such a viewpoint, the toner used in the present embodiment has an average particle diameter of 5 μm or more,
It is desirable that the thickness be less than μm.

As the main binder resin for the toner, the following can be used in addition to the polyester resin used in the above example. For example, polystyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer There are a coalescence, a polyurethane resin and the like, and if necessary, a single substance or a mixture of a plurality of binder resins can be used.

In addition, a wax component such as an olefin homopolymer or copolymer such as ethylene and propylene, and a carnauba wax may be added from the viewpoint of enhancing the releasability from the roll and preventing toner offset during heat roll fixing. At this time, the amount of the wax component added is preferably 0.5 wt% or more and 10 wt% or less based on the toner. If the amount is less than this, the effect of the wax component is not obtained. On the other hand, if the addition amount is larger than this, the toner is easily deformed by heat, and the chargeability of the developer is changed, so that a stable image density cannot be obtained.

Further, in order to increase the mechanical strength of the toner and to increase the cohesive force of the toner at the time of heat roll fixing to prevent toner offset, the weight average molecular weight is 100%.
A high molecular weight polymer of 000 or more or a crosslinked polymer may be contained. It is desirable that the content of the high molecular weight polymer or the crosslinked polymer is 60 wt% or less based on the toner. If the content is more than this, the toner may not be melt-fixed satisfactorily at the time of fixing, which may cause a problem of poor fixing.

As for the colorant of the toner, carbon black, nigrosine, graphite and the like are used as the black type.

The following can be used as the colorant of the chromatic toner. (Yellow or orange pigment) C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43,
C. I. Pigment Yellow 12, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 17, C.I.
I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I. Pigment yellow 138, C.I.
I. Pigment Yellow 174 (magenta or red pigment) C.I. I. Pigment Red 5, C.I. I. Pigment Red 48: 1, C.I.
I. Pigment Red 53: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I.
Pigment Red 123, C.I. I. Pigment Red 139, C.I. I, Pigment Red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 16
6, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222 (cyan or green pigment) C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15, C.I. I.
Pigment Blue 15: 2, C.I. I. Segment blue 15: 3, C.I. I. Pigment Blue 60 The content of the toner colorant is preferably 0.5 wt% or more and 20 wt% or less based on the toner. If the content is less than 0.5 wt%, the color developability is not sufficient and clear image quality cannot be obtained. If the content exceeds 20% by weight, unevenness in image quality due to poor dispersion of the colorant in the toner is likely to occur. <Carrier> Developing devices 4K, 4Y, 4M, 4 shown in FIG.
The carrier used in C is, for example, as follows.

Styrene-acrylic copolymer (number average molecular weight: 23000, weight average molecular weight: 98,000, Tg =
78 ° C.) 30 wt%, carbon black (basic carbon black: pH = 8.5) 3 wt%, granular magnetite (maximum magnetization 80 emu / g, particle size 0.5 μm) 67 w
t% was kneaded, pulverized and classified to give an average particle size of 45 μm. The charge polarity of this carrier is positive, the electric resistance value is 10 ¹² Ωcm, and the specific gravity is 2.2. The average particle size is a value measured with a Microtrac (manufactured by Nikkiso Co., Ltd.).

The carrier is a so-called polymer carrier obtained by mixing a magnetic fine powder with a polymer.
A magnetic particle carrier made of metal particles such as iron, ferrite, and magnetite can also be used. Since the polymer carrier generally has lower magnetization than the magnetic particle carrier, it forms a soft and high-density magnetic brush, so that a high-quality image can be obtained. In addition, there is an advantage that the possibility of damaging the surface of the image carrier when adhered to the image carrier is reduced. Further, since the specific gravity is small, the mass of the carrier is also small, so that the stress on the toner when the developer is mixed in the developing device is reduced, so that the life of the developer can be maintained for a long time.

On the other hand, the magnetic particle carrier has a large carrier mass due to the large specific gravity of the carrier, and the stress on the toner increases when the developer is mixed in the developing device. There is an advantage that it is fast, and these two types of carriers may be properly used depending on the required performance.

As for the particle size of the carrier, the smaller the particle size, the higher the density of the magnetic brush. Average particle size of 60
When the thickness is less than μm, the effect starts to appear. However, in the case of a carrier having a small particle diameter such that the average particle diameter is less than 35 μm, the magnetic binding force of the carrier is weakened, so that the carrier adheres to the latent image carrier.

From these facts, it is desirable that the average particle diameter of the carrier is 35 μm or more and 60 μm or less. <Developer> As a developer in which the toner and the carrier are mixed, for example, a toner concentration (TC: Toner Con
(centration) of 15 wt% and the toner charge amount in the developer of 20 μC / g can be used. Here, the toner concentration TC is expressed by the following equation.

TC (wt%) = (weight (g) of toner contained in developer) / (total weight (g) of developer) × 100 When the above toner and carrier are mixed to form a developer If the charge amount of the toner is too high, a phenomenon occurs in which the adhesion of the toner to the carrier becomes too high and the toner is not developed. On the other hand, if the charge amount is too low, the adhesion of the toner to the carrier is weakened, and a toner cloud due to free toner is generated, which causes fogging in printing. From the viewpoint of transferring toner and performing good development, the charge amount of the toner in the developer is 5 μC /
g to 50 µC / g, preferably 10 µC / g to 40 µ
It is desirably in the range of C / g. <Fine Particles> Next, fine particles adhered to the image carrier and the intermediate transfer member will be described.

The fine particles used in the intermediate transfer type image recording apparatus shown in FIG. 1 include the following.

For example, silica obtained by subjecting silica having an average particle diameter of 12 nm to a surface treatment using HMDS as a hydrophobizing agent can be used. Fine particles exist in a loosely aggregated state and can be dispersed relatively easily. As the fine particles, the same fine particles as the above-mentioned fine particles externally added to the toner surface can be used.

The reason why silica is used as the fine particles to be adhered to the image carrier in the present embodiment is that silica has been used as an external additive (transfer aid) of a toner and has high reliability. When used together, fine particles released from the toner are supplied to the image carrier, and the effect of the fine particles can be more stably maintained. Also in this embodiment, an external additive is used in combination for the above reason.

As the material of the fine particles, in addition to the above silica, titanium oxide, alumina, barium titanate, calcium titanate, strontium titanate, zinc oxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate , Silicon carbide, silicon nitride, chromium oxide, inorganic fine powder such as red iron oxide, and organic fine powder such as polyacrylate, polymethacrylate, polymethyl methacrylate, polyethylene, polypropylene, polyvinylidene fluoride, and polytetrafluoroethylene. . In consideration of environmental stability, it is desirable that the fine particles have as little hygroscopicity as possible. In the case of inorganic fine powder having hygroscopicity, such as titanium oxide, alumina, and silica, it is preferable to use those subjected to a hydrophobic treatment. .

The hydrophobizing treatment of these inorganic fine powders may be performed, for example, in addition to the above hexamethyldisilazane, using silanes such as dimethyldichlorosilane, decylsilane, dialkyldihalogenated silane, trialkylhalogenated silane, and alkyltrihalogenated silane. It can be carried out by reacting a hydrophobizing agent such as a coupling agent or dimethyl silicone oil with the fine powder at a high temperature.

When it is necessary to consider the problem of negative ghost generation due to light-shielding effect in using these fine particles for an image carrier, the average particle size of the fine particles depends on the wavelength of the exposure source (for example, About 660nm with LED,
It is necessary to be less than a half wavelength of about 780 nm for a semiconductor laser). In particular, in order to achieve a level at which there is no problem in image quality, it is preferable that the fine particles have an average particle diameter of 100 nm or less.

Further, it is preferable that the fine particles have transparency. In that case, as the fine particles of the organic fine powder, acrylic fine powder such as polyacrylate, polymethacrylate, polymethyl methacrylate, etc. having excellent transparency is desirable. In addition, silica is desirable as the inorganic fine powder because of its low light-shielding effect. Materials that cause these fine particles to adhere to the image carrier in the form of a film after being used for a certain period of time, such as zinc stearate and magnesium stearate, are naturally applied to the toner. In this case, the toner is apt to cause the toner to adhere to the toner. Therefore, it is not desirable to use a fine powder of a material that easily causes such filming.

Next, the fine particle adhering device 100 will be described.

FIG. 2 is a schematic configuration diagram of the fine particle adhering device in the first embodiment, FIG. 3 is a schematic structural diagram of a mesh roll used in the fine particle adhering device shown in FIG. 2, and FIG. FIG. 3 is a view showing a state where the mesh roll shown in FIG. 2 is in contact with the intermediate transfer member.

As shown in FIG.
Is a mesh outer shell 101 formed in a roll shape in which fine particles are stored inside, a cover 102 having an opening 102a on the side where the outer shell 101 contacts the intermediate transfer member, and the outer shell 101 is rotated. And a driving device 103.

The outer shell 101 is formed by forming a mesh 101a having a fine opening into a roll shape having a diameter of 20 mm, and as shown in FIG. 3, a solvent is applied to the polycarbonate flanges 101b at both ends in the roll axis direction. Adhesive, 4 mm diameter SUS round bar rotating shaft 101c penetrating the roll
With the flange 101b pulled on both sides so as to apply tension to the mesh 101a along
It is fixed to. On one side flange 101b,
There is a screw-type cap from which fine particles can be supplied into the outer shell 101. In the present embodiment, fine particles that have been surface-treated using HMDS as a hydrophobizing agent are stored in silica having an average particle diameter of 12 nm in an amount that satisfies about 50% of the inner volume of the outer shell 101.

As the mesh 101a used in this embodiment, it is preferable to use a mesh having a small opening (opening). This is because if fine particles are present as relatively large aggregates on the surface of the image carrier or the surface of the intermediate transfer member, a dot-like transfer drop may occur. Therefore, it is desirable to attach the fine particles without large aggregates so as not to become the base point of the transfer failure, and the mesh opening is preferably a small opening of 0.1 mm or less.

In the present embodiment, a nylon monofilament cloth (trade name P-25) manufactured by Kansai Wire Mesh Co., Ltd. is used. This P-25 is a JIS 462 mesh (a unit representing the size of a particle, the number of eyes per inch).
The mesh has a mesh size of 25 μm.

The fine particle adhering device 100 is similar to that shown in FIG.
As shown in FIG.
a, 5b, 6 are installed in a state of being in sufficient contact with the respective surfaces.

Next, the operation of the fine particle adhering apparatus 100 will be described with reference to FIG.

Normally, the fine particle deposition operation by the fine particle deposition device 100 is performed when the image recording device 10 is in a standby mode in which no printing is performed. First, the mesh roll 101 is rotated by the driving device 103 (see FIG. 2), and the silica fine particles stored inside the mesh roll 101 are frictionally charged by rubbing against the inner surface of the mesh roll 101. At this time, the silica fine particles are negatively charged.

Next, the intermediate transfer members 5a, 5b, 6 are rotated in the same manner as in the print mode, and a positive voltage from a high-voltage power supply used at the time of transfer is applied to each metal core. In the present embodiment, +400 V is applied to the intermediate transfer members 5a, 5b, and 6. The negatively charged fine particles receive Coulomb force due to the positive charge generated near the surface of the intermediate transfer member, are pulled out from the openings of the mesh, and are drawn to the surface of the intermediate transfer member. The fine particles attracted to and adhered to the surface of the intermediate transfer member receive a pressing force in each of the primary transfer region, the secondary transfer region, and the tertiary transfer region, and more firmly adhere to the surface of the intermediate transfer member.

Next, the driving device and the vibration device provided in the fine particle adhering device of this embodiment will be described.

FIG. 5 is a schematic diagram of a driving device and a vibration device provided in the fine particle adhering device of the first embodiment.

As shown in FIG. 5 (a), in the fine particle adhering device 100, the rotating shaft 101c inserted into the mesh roll 101 containing the fine particles therein is provided with bearings 101d provided at both ends in the roll axis direction. To the frame of the image recording apparatus.

The rotating shaft 101c has gears 101h and 101g.
Driven by a drive motor 101j via i.

The fine particle adhering device 100 of the present embodiment employs a method in which the mesh roll 101 is rotated by the driving device including the gears 101h and 101i and the driving motor 101j. In particular, the driving device is provided. Without causing friction between the mesh roll 1 and the intermediate transfer member.
01 may be driven.

The fine particle adhering device 100 of the present embodiment includes:
The outer shell 101 of the mesh using the driving device 103 described above.
A vibrating device for vibrating is incorporated. That is,
The gear 101h is provided with a cam driven gear 101g that is driven to rotate.
Is a metal ball 10 partially embedded in the bearing 101d.
It is pressed against the bearing 101d by the spring 101k so as to be always in contact with 1f.

As shown in FIG. 5B, the gear 1 with cam
A groove 101g_ is provided on the surface facing the 01g metal ball 101f.
1, the metal ball 101f fits into the groove 101g_1 every time the cam-equipped gear 101g makes one rotation, so that the main body of the mesh roll 101 moves to the left as viewed in the drawing, and the mesh roll 101 itself and the inside thereof move. Vibration is applied to the stored particles.

Not only this type of vibration device, but also a vibration device configured to vibrate the mesh roll using, for example, a piezo vibrator may be used. In that case, the outer shell of the mesh does not necessarily have to be in a roll shape, and an outer shell of any shape can be adopted.

Further, in the present embodiment, a method of attracting the charged fine particles by Coulomb force when pulling out the fine particles from the mesh is adopted. However, a method of sifting the fine particles by using gravity like a so-called sieve is used. There may be.

In the fine particle attaching operation, the fine particles are transferred to the intermediate transfer member 5.
In the initial state in which no particles are attached to a, 5b, and 6 at all, it is necessary to perform the operation before printing. However, once the particles are attached, when the particles are insufficient, that is, when the transfer efficiency is slightly reduced. May be appropriately implemented.

As a result of a separate study, the amount of the attached fine particles was determined to be about 10%, ie, the area ratio, that is, the ratio of the projected area of the fine particles per unit area of the image carrier or the intermediate transfer member was about 10%
It has been found that high transfer efficiency is exhibited when the ratio exceeds the maximum value. Therefore, in the present embodiment, the amount of attached fine particles on the intermediate transfer members 5a, 5b, 6 is set to be 15 to 20% in area ratio. are doing.

Regarding the state of adhesion of the fine particles on the surface of the image carrier or the surface of the intermediate transfer member, only one type of fine particles may be present, or a plurality of types of fine particles may be present at the same time. The point is that fine particles are interposed between the toner and the image carrier, or between the toner and the intermediate transfer member, so that the adhesive force between the toner and the image carrier or the adhesion between the toner and the intermediate transfer member. What is necessary is just to be able to reduce the adhesion.

Next, the color image recording apparatus 1 of the present embodiment
The operation of 0 will be described with reference to FIG.

Drum-shaped image carriers 1K, 1Y, 1M, and 4K corresponding to four colors of black, yellow, magenta, and cyan, respectively.
1C is driven to rotate in the direction of arrow A, and the surface of each image carrier is uniformly charged by the corresponding charger 2K, 2Y, 2M, 2C.

Image light is applied to the surface of the photosensitive layer of each image carrier at a position facing each of the image writing devices 3K, 3Y, 3M, and 3C corresponding to each image carrier. The charge on the photoreceptor layer of the image carrier is reduced by exposure to form a latent image due to a difference in electrostatic potential.

These latent images are conveyed to the positions facing the corresponding developing devices 4K, 4Y, 4M, and 4C, and are developed with black, yellow, magenta, and cyan toners transferred from each developing roll. The image is visualized, and a toner image of each color is formed.

Of the toner images thus formed, the magenta toner image and the cyan toner image are sequentially superimposed and transferred onto one of the first intermediate transfer drums 5b (1).
Next, the secondary transfer is collectively performed on the second intermediate transfer drum 6. On the other hand, the black toner image and the yellow toner image are sequentially superimposed and transferred (primary transfer) to the other first intermediate transfer drum 5a, and then the cyan toner image and the magenta toner on the second intermediate transfer drum 6 are transferred. The image is secondarily transferred collectively onto the image. The four color toner images thus formed on the second intermediate transfer drum 6 are collectively transferred (tertiary transfer) onto the recording paper P by the transfer roller 7.

The toner images on the first and second intermediate transfer members adhere to the surfaces of the respective intermediate transfer members via fine particles, and the non-electrostatic adhesion force such as van der Waals force is reduced. As a result, it is easily separated from the intermediate transfer member by the electric field, and the transfer is performed at a transfer efficiency of almost 100%. The toner image is finally fixed by the fixing device 9 to obtain a color recorded image.

As described above, the toner images are primarily transferred from the image carrier to the two first intermediate transfer members, and the toner images are secondarily transferred from the respective first intermediate transfer members to the second intermediate transfer member. The toner image is tertiary-transferred from the second intermediate transfer member to the recording paper P. Each of the image carriers, the first intermediate transfer member, and the second
Since no residual toner remains on the intermediate transfer member, this image recording apparatus does not require a cleaning device, and a cleanerless image recording apparatus without waste toner can be realized.

The reason why a plurality of drum-shaped intermediate transfer members are used in the image recording apparatus of the present embodiment is as follows. That is,
Since the drum-shaped intermediate transfer body is a rigid body, there is no elongation in the toner image conveying direction such as a belt, and no walk phenomenon accompanying the belt running. Therefore, compared to an image recording apparatus using a belt-shaped intermediate transfer member, the accuracy of color superposition can be easily obtained, which is suitable for multiple transfer. However, when only one drum-shaped intermediate transfer member is used, the image forming portion (image carrier + charger + image writing device + developing device) is arranged radially because the intermediate transfer member is cylindrical. Will be done. Therefore, it is difficult to share parts such as the developing device. In addition, there may be a problem that the arrangement of the image writing device is complicated. Therefore, in order to secure the accuracy of color superposition by using a plurality of drum-shaped intermediate transfer members and to use common components such as a developing device, an image recording device having a configuration as shown in FIG. Becomes effective.

Next, the mesh roll 1 of the fine particle adhering device was used.
For 01, to investigate the effect of mesh aperture,
A comparative experiment was performed by preparing a mesh having openings different from the mesh used in the first embodiment. Specifically, six types (mesh 1 to mesh 6) having different mesh openings in the range of 40 μm to 140 μm are prepared, and a mesh roll is prepared in the same manner as in the first embodiment, and fine particles are formed under the same conditions. After attachment, a transfer experiment was performed.

Table 1 shows details of mesh openings used in the experiment and evaluation results. In addition, the evaluation of the experiment was performed based on the secondary transfer efficiency and the presence or absence of a transfer defect.

The transfer efficiency was obtained from the following equation.

Transfer efficiency (%) = (weight of transferred toner (g)) / (weight of toner before transfer (g)) × 100 The presence or absence of transfer failure is determined by the form of transfer failure after transferring a solid image. The presence or absence of a white spot, which was observed as, was visually confirmed and determined.

The overall judgment in Table 1 is the result of judging both the secondary transfer efficiency and the transfer failure.

From the results in Table 1, it is possible to obtain high transfer efficiency even if the mesh openings are increased to some extent.
In the case of openings larger than 100 μm, occurrence of transfer blemishes is observed, and it can be seen that the mesh openings need to be 100 μm or less.

[0093]

[Table 1]

Next, a second embodiment of the present invention will be described.

FIG. 6 is a schematic diagram showing a second embodiment of the image recording apparatus of the present invention.

The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The image recording apparatus 20 is substantially the same as the image recording apparatus 10 of the first embodiment, except that the image carriers 1K, 1Y, 1M, and 1C are respectively provided with a fine particle adhering device 200 and a charge applying means 22. The first point is that
This is different from the image recording apparatus 10 in the embodiment.
The fine particle attachment device 200 has substantially the same structure as the fine particle attachment device 100 (same as that in the first embodiment) provided in each intermediate transfer member.

FIG. 7 is a schematic configuration diagram of a fine particle adhering device according to the second embodiment.

As shown in FIG. 7, this fine particle adhering device 2
Reference numeral 00 denotes a roll-shaped mesh outer shell 201 containing fine particles therein, and a cover 202 having an opening 202a on the side where the outer shell 201 comes into contact with the intermediate transfer member.
And a driving device 203 for rotating the outer shell 201. In short, the fine particle attachment device 1 of the first embodiment
00 is downsized, including mesh specifications,
All are made almost the same.

The fine particles used in the present embodiment are the same as the fine particles used in the first embodiment, and are stored in an amount that satisfies about 50% of the internal volume of the mesh roll.

In the present embodiment, fine particles can be uniformly and stably adhered to the surface of the image carrier by the fine particle adhering device 200, so that high transfer efficiency can be maintained for a long period of time.

In each of the embodiments described above, an example of a color image recording method has been described. However, the same effect can be obtained in a monochrome image recording method. Although the above embodiments have been described using examples of the electrophotographic recording system based on the Carlson process, any indirect recording system that performs transfer to recording paper, such as a chargeless system or a backside exposure system, may be applied. It is possible. Others
It is also effective in the case of an image recording apparatus of a system in which an electrostatic latent image is written using a dielectric instead of a photoconductor, developed, and transferred, such as an electrostatic recording system or an ionography system.

[0103]

As described above, according to the image recording apparatus of the present invention, the image carrier has the outer shell of the mesh, the fine particles are stored in the outer shell, and the fine particles discharged from the mesh are transferred to the image carrier. Is provided with a fine particle adhering means for adhering to the surface of the image carrier and / or the surface of the intermediate transfer member, whereby the fine particles can be uniformly and stably adhered to the surface of the image carrier or the surface of the intermediate transfer member. A cleanerless image recording apparatus which is present between the surface or the intermediate transfer member surface and the toner image and can steadily reduce the adhesive force, thereby achieving a transfer efficiency close to 100% and generating no waste toner. Can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a first embodiment of an image recording apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of a particle attachment device according to the first embodiment.

FIG. 3 is a schematic configuration diagram of a mesh roll used in the fine particle attachment device shown in FIG.

FIG. 4 is a diagram showing a state in which the mesh roll shown in FIG. 2 is in contact with an intermediate transfer member.

FIG. 5 is a schematic diagram of a driving device and a vibration device provided in the fine particle adhering device of the first embodiment.

FIG. 6 is a schematic configuration diagram showing a second embodiment of the image recording apparatus of the present invention.

FIG. 7 is a schematic configuration diagram of a fine particle attachment device according to a second embodiment.

[Explanation of symbols]

 1, 1K, 1Y, 1M, 1C Image carrier 2K, 2Y, 2M, 2C Charger 3K, 3Y, 3M, 3C Image writing device 4K, 4Y, 4M, 4C Developing device 5a, 5b First intermediate transfer member 6 Second intermediate transfer member 7 Transfer roller 8 Conveying roller 9 Fixing device 10, 20 Image recording device 11 Paper guide 12, 22 Charge applying means 100, 200 Particle attaching device 101, 201 Outer shell (mesh roll) 101a Mesh 101b Flange 101c Rotating shaft 101d, 101e Bearing 101f Metal ball 101g Gear with cam 101g_1 Groove 101h, 101i Gear 101j Drive motor 101k Spring 102 Cover 102a, 202a Opening 103, 203 Drive P Recording paper

Claims (7)

[Claims] 1. A toner image is formed on a predetermined image carrier.
The toner image formed on the image carrier is transferred to a predetermined intermediate transfer member, and the toner image transferred on the intermediate transfer member is transferred to a predetermined recording medium and fixed, thereby forming an image on the recording medium. An image recording apparatus for recording an image, comprising: a mesh outer shell, wherein fine particles are stored inside the outer shell, and fine particles discharged from the mesh are transferred to the surface of the image carrier and / or the surface of the intermediate transfer member. An image recording apparatus, comprising: means for attaching fine particles to a surface. 2. The image recording apparatus according to claim 1, wherein said fine particle attaching means has a mesh outer shell formed in a roll shape. 3. An image recording apparatus according to claim 2, wherein said fine particle adhering means includes a driving device for rotating said outer shell. 4. The image forming apparatus according to claim 1, wherein the fine particle attaching means transfers a charge for generating a force for attracting the fine particles stored in the outer shell to the image carrier or the intermediate transfer member. 2. The image recording apparatus according to claim 1, further comprising a charge applying means for applying the charge to the surface of the body. 5. The image recording apparatus according to claim 1, wherein said fine particle attaching means has an outer shell formed of a nylon mesh. 6. The image recording apparatus according to claim 1, wherein said fine particle attaching means has an outer shell formed of a mesh having an opening of 0.1 mm or less. 7. The image recording apparatus according to claim 1, wherein said fine particle attaching means includes a vibration device for vibrating said outer shell.