JPH081944A - Image forming apparatus and image forming method using the same - Google Patents

Abstract

(57) [Summary] [Object] To provide an image forming apparatus capable of minimizing the number of replacement parts, improving the image forming speed, and obtaining a high-density image, and an image forming method using the same. Offering Offering. A cylinder (12) having a plurality of fine holes (12C) in a peripheral wall (12A), and a colored body based on a magnetic fluid (20) having a flowable viscosity is enclosed therein, The magnetic force is arranged outside the fine holes (12C), and selectively generates a magnetic force in the circumferential and axial directions of the cylinder (12) in a direction in which the magnetic fluid (20) is leached from the fine holes (12). An exciting body (22) having a magnetic force generating portion on a surface facing the cylinder, and a magnetic fluid is excited by the exciting body (22).
An image is formed by leaching it on the cylindrical surface by controlling the magnetic force from As a result, only the cylindrical portion corresponding to the conventional photoconductor needs to be replaced as a cartridge, and the number of replacement parts or discarded parts can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and an image forming method using the same.

[0002]

2. Description of the Related Art Generally, as a method for copying an original, an electrophotographic method or an ink jet method is known. These copying methods have problems that the structure of the apparatus itself is complicated and that the formed image has a phenomenon such as bleeding and the image quality is not good.

On the other hand, in recent years, in order to eliminate the above-mentioned drawbacks of the copying methods, a copying method has been proposed in which the magnetic fluid is regarded as ink and the magnetic fluid is attached to an image carrier such as a photoconductor. (For example, published on May 23, 1988, published by Nikkan Kogyo Shimbun, "Magnetic Material" -Basics and Applications, No. 6
(Description in (3.5) on pages 7 to 70) In the copying method described in the above publication, an ink material in which ferromagnetic colloid particles such as magnetite are mixed in a solvent is used, and the ink material is discharged from a nozzle. There is a configuration in which the direction is corrected by a plurality of magnetic poles until the ink is ejected and reaches the ink adhering surface, and the ink is adhered to a predetermined image forming position. Further, as a configuration different from such a system, there is one called a magnet field graph. As an example, a stylus is constructed by arranging iron-nickel wires (diameter 50 μm) at a predetermined interval on the magnetic pole surface of a magnet, and by applying a high-pressure pulse to the selected stylus, the magnetic fluid is directed toward the facing paper or the like. The ink is attached by rising.

[0004]

By the way, many of the structures used in the image forming system using the magnetic fluid as described above are complicated. That is, in each of the above-described configurations, since the magnetic fluid used as ink is ejected, image formation becomes impossible due to clogging of the ejection portion, or the magnetic fluid is directed toward the nozzle or stylus. The structure of the magnetic fluid supply unit including the storage unit for supplying the fluid is required, and the device tends to be large-scale. Also, the time and effort required for disposal due to consumption of the magnetic fluid is not easy due to the complicated structure.

Therefore, in view of the problem of forming an image by using magnetic fluid as ink, the object of the present invention is to simplify the supply structure of the magnetic fluid used as ink, and
An object of the present invention is to provide an image forming apparatus capable of improving resolution with a simple configuration that only uses the characteristics of magnetic fluid.

[0006]

In order to achieve this object, the invention according to claim 1 is characterized in that a cylinder having a plurality of fine holes in its peripheral wall and a cylinder which is enclosed in the cylinder and has an appropriate viscosity. A colored body based on a magnetic fluid made of powder, and an exciting body that is located outside the cylinder and selectively applies a magnetic force to leach the colored body from the fine holes,
Means for transferring the leached colored body to an image carrier.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the cylinder is a cartridge in which both axial end faces are closed, and the cylinder is detachably and rotatably supported with respect to the apparatus main body. It is characterized by being.

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the cylinder has a magnetic body inside, and magnetic forces of magnetic poles of the magnetic body facing the exciting body are adjacent to each other. An image forming apparatus for shaving, which is characterized by being set weaker than the magnetic force of magnetic poles.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, the cylinder has an insertion portion into which a magnetic member can be inserted, which is formed in the central portion, separately from the space for enclosing the magnetic fluid. When being detached from the apparatus main body, a magnetic member is inserted into the insertion portion so that the enclosed magnetic fluid is sucked inward.

According to a fifth aspect of the present invention, in the image forming apparatus according to the first aspect, the exciting body is set to have a magnetic force stronger than the magnetic force of the magnetic pole located in the cylinder.

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the magnetic body disposed in the cylinder has a magnet at a position facing the exciting body. It is characterized in that a magnetic pole having the same polarity as that of the magnetic pole on the side of the exciter is arranged.

According to a seventh aspect of the present invention, there is provided an image forming method using the apparatus according to the first aspect, wherein a cylinder having a plurality of fine holes in a peripheral wall and a coloring body based on a magnetic fluid is enclosed therein. And an exciter that is disposed outside the micropores and that has a magnetic force generation unit that selectively generates a magnetic force in a circumferential direction so as to leach the magnetic fluid from the micropores. A step of forming an image by leaching the magnetic fluid from the micropores by selectively applying a magnetic force to the micropores, and a transfer step of transferring the image to an image carrier,
It is characterized by including.

[0013]

In the inventions of claims 1 and 3, since the magnetic fluid enclosed in the cylinder is consumed by being exuded to the outside by the exciter, only the cylindrical part can be a replacement part.

According to the second aspect of the invention, it is possible to perform an operation of only attaching and detaching the cylinder.

According to the fourth aspect of the invention, when the cylinder is removed from the apparatus, the influence of the magnetic substance disappears and it is possible to prevent the cylinder from leaching out unnecessarily.

According to the fifth aspect of the invention, since the magnetic force acting on the magnetic fluid is larger than the magnetic force of the magnetic pole, the magnetic fluid can be easily leached onto the drum surface.

According to the sixth aspect of the present invention, it is possible to generate a magnetic pole that is easily attracted by the exciter in the magnetic fluid located between the exciter and the magnetic body and that is easily repelled by the magnetic body. .

According to the seventh aspect of the invention, the formed image on the cylindrical surface can be obtained by the shortest copying cycle of only transfer.

[0019]

The details of one embodiment of the present invention will be described below.
FIG. 1 is a schematic view showing an example of an image forming apparatus according to the present invention. The image forming apparatus 10 includes a cylindrical visible image drum 12 rotatable in the direction of the arrow shown in the figure.
An image is formed on the surface of No. 2. This image formation will be described later in detail. Visual drum 12
A transfer material 16 such as a transfer paper sent from the paper feeding device 14 comes into contact with the transfer device 16 and the visualized image formed on the surface of the visualized drum 12 is transferred. For this reason,
A holding roller 18 for holding and transferring the transfer material 16 while pressing the transfer material 16 against the surface of the developing drum 12 is provided at a position corresponding to a transfer portion set on a part of the peripheral surface of the developing drum 12. It is brought into contact with 12 so as to be able to rotate together.
The sheet feeding device 14 includes a cassette 14A that stores a transfer material,
It is equipped with a feeding roller 14B and a separating device 14C.
The feeding roller 14B contacts the delivery side of the transfer material 16 located at the uppermost position in the paper feeding cassette 14A, and rotates the transfer material 16 by a predetermined amount by a drive signal from a control unit (not shown). It is designed to be extended. Separator 14
C is for preventing the double feeding of the transfer material, and is smaller than the friction coefficient between the feeding roller 14B and the transfer material.
A material having a friction coefficient larger than that of the transfer materials is selected. As a result, among the transfer materials 16 in the double-fed state, the transfer material 16 located in the lower part is held by the separating member 14C, and only the transfer material 16 located in the upper part is conveyed. In FIG. 1, reference numeral 17 indicates a paper discharge roller, and reference numeral 19 indicates a paper discharge tray.

The visible drum 12 is, for example, a cylindrical member having an inner cylinder 12A and an outer cylinder 12B made of a non-magnetic material such as aluminum. The outer cylinder 12B has a large number of fine holes over its entire surface. 12C is formed. Visual drum 1
The thickness of the second outer cylinder 12B is set to be relatively thin, and the passage length required for the exudation of the magnetic fluid described later is shortened. The developing drum 12 is detachably and rotatably supported with respect to the apparatus main body and is used as a replaceable cartridge.

The magnetic fluid 20 is, as shown in FIGS.
It is enclosed in a space between the inner cylinder 12A and the outer cylinder 12B of the image-visualizing drum 12, and usually has a viscosity set so as not to spontaneously flow out from the fine holes 12C. The magnetic fluid 20 is
For example, it is a magnetizable powder material in which ferromagnetic colloid particles such as magnetite are mixed in a solvent, and can move according to the strength of the magnetic force in the atmosphere. Furthermore, magnetic fluid
Of the mixture, when magnetite is mixed, it can be regarded as a colored body because the magnetite itself is black, but if necessary, separately mixed colored colloidal particles to form a colored body (hereinafter, referred to as a colored particle). ) Is possible.

In order to form an image with the magnetic fluid 20 as described above, a magnetic head 22 serving as an exciter is arranged in contact with or in close proximity to the upstream side of the transfer position in the rotation direction of the image development drum 12. . The magnetic head 22 is for forming an image by allowing the magnetic fluid 20 enclosed in the visualizing drum 12 to seep to the drum surface,
As shown in FIG. 3, as many exciting elements 22A as the number corresponding to the pixel density are arranged along the axial direction of the visible image drum 12.
The arrangement interval and the arrangement position of the exciting elements correspond to the fine holes 12C described above. Each exciting element 22A is composed of an electromagnet as an example, and is selectively magnetized by energizing a power supply unit (not shown) to a position corresponding to pixel information.

The exciting elements 22A can be arranged not only in a single row but also in a plurality of rows as shown in FIG. As a result, the excitation range corresponding to the image information can be expanded to accelerate the image forming speed.

A magnetic body 26 is inserted inside the developing drum 12 in the vicinity of the magnetic fluid storage space, that is, inside the inner cylinder 12A in this embodiment. The magnetic body 26 is provided in order to prevent the magnetic fluid from exuding excessively, and the magnetic poles are arranged in a state in which different poles are adjacent to each other in order to attract the magnetic fluid into the visualizing drum 12. As a result, the magnetic fluid is held in the visualizing drum 12 along the magnetic lines of force formed between the magnetic poles. Of the magnetic body 26, the magnetic pole 26A at the position facing the magnetic head 22 is, as shown in FIGS.
Those having the same polarity are arranged, and their magnetic forces are set to be weaker than those of other adjacent magnetic poles. In FIGS. 4 and 5, the magnitude of the magnetic force is replaced with the magnitude of the magnetic poles to be schematically shown.

In FIG. 4, the S poles face each other as the magnetic poles that face the S poles of the magnetic head 22, and in FIG. 5, the N poles face each other. In this way, among the adjacent magnetic poles, the magnetic force of the magnetic pole arranged at the position facing the magnetic head 22 is made weaker than the magnetic force of the other magnets, whereby the magnetic head 22 and the colored particles of the magnetic fluid are separated from each other. It is possible to facilitate the exudation of the magnetic fluid due to the magnetic force generated between them. This can be achieved by making the magnetic force of the magnetic head 22 stronger than the magnetic force in the visualizing drum 12.

In general, as shown in FIG. 6, when a magnetized body is brought close to a magnet, an opposite magnetic pole is induced at one end of the magnetized body facing the magnet, and the magnetic pole is chained to this magnetic pole. A polarity for maintaining magnetic neutrality is generated up to the other end. For this reason, a polarity opposite to that of the magnetic head 22 is generated inside the magnetized body facing the magnetic head 22 and is easily attracted. On the other hand, the magnetic head 22 is provided on the side opposite to the side facing the magnetic head 22 with this magnetic pole as a reference.
A magnetic pole having a polarity opposite to the polarity of the side facing is generated (because the magnetic balance is maintained). Since the polarity of the magnetized body on the side opposite to the magnetic head 22 is the same as the polarity of the magnetic pole on the magnetic body 26 side, the magnetized body is easily repelled.

Based on such magnetic characteristics, the following relationship is set between the magnetic head 22 and the magnetic body 26 in this embodiment.

F1 = λ / λaU1 <f2 = λ / λaU2 By providing such a difference in the strength of the magnetic force, the magnetic head 22 is easily attracted to the magnetized body, and the magnetic property is Since the influence of the repulsive force acts on the body 26 side, the colored particles can be easily leached from the fine holes 12C of the drum 12.

Regarding such exudation of the magnetic fluid, the size of the character is replaced by the magnitude of the magnetic force in FIG.

The relationship of the magnetic force to the colored particles which are strips is as follows.
It is also affected by the distance between the magnetic poles. That is, since the magnetic force acting on the colored particles is inversely proportional to the square of the distance between the magnetic pole and the colored particles, the closer the magnetic head 22 is to the magnetic fluid (the more it moves in the + direction in FIG. 6), the greater the attractive force becomes. The colored fluid can be leached onto the drum surface. Therefore, it is possible to position the magnetic head 22 so as to maintain the above relationship.

The setting of the magnetic force in each magnet, especially in the magnetic head 22, may be performed by controlling the current value supplied to the coil of the exciting element 22A of the exciting pair 22 formed of the electromagnet.

Since the present embodiment is constructed as described above,
To describe the visualization process, the following steps are performed. First, as the device used in the procedure described below, the device having the above-described configuration is used. Visual drum 12
Starts rotating when copying is started.

On the other hand, the magnetic head 22 includes the visualizing drum 12
When the fine holes 12A of 12 correspond to the position corresponding to the image information, the above-mentioned magnetic force relationship is set by energizing the exciting element 22A facing the position. When the colored particles of the magnetic fluid are exuded from the fine holes 12A of the visualizing drum 12, an image of the colored particles of the magnetic fluid is formed on the surface of the visualizing drum.

The image thus formed on the surface of the developing drum 12 is carried up to the position of the sandwiching roller 18 adjacent to the magnetic head 22 and pressure-bonded to the transfer material 16 fed from the paper feeding device 14. Alternatively, it is transferred by heating and fusing.

When the magnetic fluid 20 contained in the developing drum 12 is consumed and does not maintain a predetermined amount, the developing drum 12 is replaced. When replacing the visible drum 12, the visible drum 12 is removed from the support portion of the apparatus main body and taken out. The visualized drum 12 that has been taken out is in a state in which no constraint force is exerted on the magnetic fluid contained therein. Therefore, instead of the magnetic body 26, the magnet rod 30 is inserted into the visualized drum 12, and It is designed to avoid unwanted leaching of fluid.

In this way, the magnetic head 22 and the visual image drum 1 are
When the colored particles of the magnetic fluid are exuded from the inside of the visualizing drum 12 due to the magnetic force relationship with the magnetic body 26 in the second magnetic fluid and the magnetic fluid is consumed, the situation in which the amount of the magnetic fluid necessary for the visualizing process becomes insufficient. Invite. In this embodiment, the shortage of the magnetic fluid is determined by detecting the weight of the optical element or the image development drum 12, and the replacement time is displayed.

As described above, according to the present embodiment, the magnetic pole relationship between the magnetic head 22 and the magnetic body 26 is set such that the magnetic fluid has a polarity such that suction is generated on one side and repulsion is generated on the other side. The magnetic fluid can be easily leached out only by selecting. Further, according to the present embodiment, when the visualizing drum is taken out, it is possible to avoid the magnetic fluid from leaching out only by inserting the magnet rod, so it is possible to prevent the hand from getting dirty during maintenance. You can

[0038]

As described above, according to the first and third aspects of the present invention, since the discarding or replacing part need only be the cylinder containing the magnetic fluid, the number of discarding parts or replacement parts can be reduced. It can be reduced.

According to the second aspect of the present invention, since a simple operation of attaching and detaching only the cylinder is possible, the labor required for maintenance work can be reduced.

According to the fourth aspect of the invention, the magnetic fluid can be prevented from leaching out when the cylinder is taken out, so that the peripheral portion where the device is installed is not contaminated.

According to the fifth aspect of the present invention, since the magnetic fluid leaching operation is easily performed, the processing time required for image formation can be shortened and an image can be easily obtained.

According to the sixth aspect of the present invention, since the force for leaching the magnetic fluid toward the outside of the cylinder can be easily set, it is possible to form an image of Yai rather than with a simple structure. become.

According to the invention described in claim 7, the image formed on the cylindrical surface can be obtained as a copy only by being transferred, so that the copying cycle can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the configuration of an image forming apparatus that is an embodiment of the present invention.

FIG. 2 is a partial schematic diagram for explaining a relationship between a cylinder and an exciting body used in the device shown in FIG.

FIG. 3 is a schematic perspective view for explaining the configuration of an exciter used in FIG.

FIG. 4 is a schematic diagram for explaining the relationship between opposing magnetic poles of a cylinder and an exciting body used in the device shown in FIG.

5 is a schematic diagram for explaining another relationship between the opposing magnetic poles of the cylinder and the exciter used in the device shown in FIG.

FIG. 6 is a schematic diagram for explaining a state in which the magnetic fluid is leached to the outside of the cylinder.

7 is a schematic perspective view for explaining the relationship between a cylinder and a magnetic body used in the device shown in FIG.

8 is a schematic diagram for explaining a state when the cylinder used in the device shown in FIG. 1 is retracted from the device main body.

[Explanation of symbols]

 10 Image Forming Apparatus 12 Cylinder 12A Inner Cylinder 12B Outer Cylinder 14 Paper Feeding Device 16 Transfer Material 20 Magnetic Fluid 22 Magnetic Head Forming Exciter 22A Exciting Element 26 Magnetic Material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03G 15/05 G03G 15/00 115

Claims (7)

[Claims] 1. A cylinder having a plurality of fine holes in its peripheral wall, a magnetic fluid-based coloring body made of magnetizable powder having an appropriate viscosity, which is enclosed in the cylinder, and is located outside the cylinder. An image forming apparatus comprising: an exciting body for leaching the colored body from the fine holes by selectively applying a magnetic force; and a means for transferring the leached colored body to an image carrier. . 2. The image forming apparatus according to claim 1, wherein the cylinder is a cartridge whose both axial end surfaces are closed, and which is rotatably supported by the apparatus main body. Image forming apparatus. 3. The image forming apparatus according to claim 1, wherein the cylinder has a magnetic body inside, and a magnetic force of a magnetic pole of the magnetic body facing the exciting body is weaker than a magnetic force of an adjacent magnetic pole. An image forming apparatus for shaving, which is characterized by being set. 4. The image forming apparatus according to claim 1, wherein the cylinder has an insertion portion into which a magnetic member can be inserted, which is formed in the center of the cylinder, separately from the space for enclosing the magnetic fluid, and is separated from the apparatus main body. The image forming apparatus is characterized in that, at this time, a magnetic member is inserted into the insertion portion and the enclosed magnetic fluid is sucked inward. 5. The image forming apparatus according to claim 1, wherein the exciting body is set to have a magnetic force stronger than a magnetic force of a magnetic pole located in the cylinder. 6. The image forming apparatus according to any one of claims 1 to 3, wherein in the magnetic body disposed in the cylinder, a magnet at a position facing the exciting body is the same as a magnetic pole on the exciting body side. An image forming apparatus in which polar objects are arranged. 7. An image forming method using the apparatus according to claim 1, wherein the peripheral wall has a plurality of fine holes, and a cylinder containing a colored body based on a magnetic fluid therein, and the fine holes. An exciter disposed externally, the exciter including a magnetic force generating portion that selectively generates magnetic force in a direction in which the magnetic fluid is leached from the fine holes in the circumferential direction, and An image forming method comprising: a step of selectively applying a magnetic force to leach the magnetic fluid from the fine holes to form an image; and a transfer step of transferring the image to an image carrier.