JPS5830581B2 - Rotating member for image forming device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a rotating member applied to an image forming apparatus.

Taking an electrophotographic copying device as an example of an image forming device, in devices that conventionally use a liquid developer, as a means of development, liquid squeezing, cleaning, etc.
Elastic rollers have been used in each of the above locations.

One example of this type of elastic roller is one in which only an open cell material such as rubber foam, plastic foam, urethane foam, etc. is provided with a uniform thickness on the surface of the rotating shaft at the center.

Such a conventional elastic roller rotates in pressure contact with the surface of a rigid member such as a photoreceptor or an insulating member, forms a desired nip width, and squeezes out the liquid that has been sufficiently absorbed, or vice versa. It has the effect of

For this reason, the above elastic roller has been considered to be highly applicable for use in developing sections and cleaning sections.

However, the following drawbacks have been pointed out to the above roller.

That is, when the foam member contacts a rigid surface, the contact pressure and contact width of the nip portion due to the contact become non-uniform due to the uneven hardness.

Other problems include unevenness in the particle size of the bubbles in the foam member and non-uniformity in the size and shape of the bubbles on the surface.Furthermore, when pressed against a rigid surface, the bubbles on the roller surface are crushed at the nip. This causes uneven contact in narrow areas or spots.

For example, if it is used in a developing section, uneven density will appear in the image at the developed area.

Furthermore, during pressure contact, the surface of the elastic roller comes into close contact with the surface of the photoreceptor and moves in a direction other than the vertical direction, which may rub the developer and disturb the developed image.

As mentioned above, when the elastic roller mentioned above comes into pressure contact with a rigid member, the contact pressure is uneven, and the air bubbles on the roller surface are crushed at the nip. Uniform Good absorption or expression of liquid is not possible.

In addition, when such an elastic roller is used as a developing means, it is desirable that the vicinity of its surface be made conductive so as to have an electrode effect.

This is because development is possible at high speed, with little fog, and without edge effects.

Conventionally, for this purpose, it has been proposed to mix conductive material powder such as carbon into the foam member of the elastic roller, or to further cover the foam member with a metal net.

However, various drawbacks have been pointed out even with such measures.

For example, if the former measure is taken, the flexibility of the cellular member will decrease, plastic deformation will occur more easily, the mechanical strength will further decrease, and, as explained above, the cellular member will have uneven hardness and bubble particle size. Based on the above, it has been pointed out that the liquid absorption and squeezing effects are poor.

On the other hand, the latter method has the disadvantage of disturbing the latent image because the conductive metal net comes into direct contact with the latent image.

In any case, in order to obtain a good electrode effect, it is necessary that the conductive portion be in close proximity to the latent image without being in direct contact with the latent image.

Therefore, the main object of the present invention is to provide a versatile rotating member that solves the problems of conventional rotating members (for example, elastic rollers), and further objects has an electrode effect at least in the vicinity of its surface, and satisfies the conditions that the conductive part approaches the latent image carrying surface without directly contacting it, and then the conductive part is uniform in the nip part. If contact and sufficient liquid movement (transfer/reception) is possible on the contact surface t, and if the rigid member is rotated or rotated at the same circumferential speed as the opposing rigid member, the surface of the rigid sound crucible may be pressed into an unfavorable state. The object of the present invention is to provide a cooperating member that does not require any damage.

Other purposes include a developing means for a latent image carrier in an image forming apparatus using a liquid, a liquid squeezing means for removing excess developer on the carrier after development, a cleaning means for the carrier, etc. An object of the present invention is to provide a rotating member in the form of a roller or an endless belt that handles liquid.

The rotating member of the present invention that achieves the above-mentioned object has a layer of porous elastic material that allows liquid to pass therethrough, and a layer that squeezes out liquid when compressed and absorbs liquid when restored from the compressed state. A movable member, of the surfaces of the rotary member, at least a surface that can come into contact with another member is insulative, and
Most of the outer periphery is characterized by being configured to have an electrode effect.

Here, in summary, the rotating member of the present invention does not cause deformation in the direction of the contact surface at the pressure contact position when it comes into pressure contact with the opposing rigid image holding member, but has elasticity in the direction perpendicular to the contact surface. Due to the deformation characteristics and elastic deformation accompanied by spatial deformation of the bubble part,
A rotary member configured in the shape of a roller or an endless belt that has both the property of absorbing and squeezing liquid and the property of exhibiting an electrode effect in close proximity to the image holding member without directly contacting it. .

In the present invention, the material constituting the outer layer will be explained below.

That is, it can be seen as a composite of an insulating material and a conductive material.

More specifically, for example, a part of the base material of a woven or knitted fabric made of a conductive material such as a metal, or a metal film with a large number of holes (that is, a part of the base material) The outer layer (the part where the outer layer contacts another member such as an image holding member) is coated with an insulating material, or conversely, a woven or knitted fabric made of an insulating material, or an insulating film with many holes perforated. It can be roughly divided into those in which a part of the base material (that is, the part where the outer layer contacts another member such as an image holding member) is left, and the other part is covered with a conductive material. .

In terms of more specific methods, only the necessary parts of the base material are coated with an insulating material or a conductive material, or
After uniformly covering the insulating material or conductive material, unnecessary portions are stripped of the covering.

Even if it falls down, for example, directly with other members such as an image holding member,
Those skilled in the art will readily understand that various modifications can be made as long as contactable parts are insulated and other parts have an electrode effect.

A specific example is given for reference.

For example, a resin paint is applied only to a predetermined surface of a metal mesh.

At this time, it is also effective to mask the uneasy surface so that it will not be coated.

Alternatively, the entire metal wire may be coated with a resin paint, and later the paint on one predetermined side may be scraped off using sandpaper or the like, or it may be wiped off with a drop of solvent dissolved therein.

Alternatively, a large number of small holes may be formed in woven or knitted fabrics of synthetic resin fibers (e.g., nylon, Tetron, vinylon, acetate, cotton, silk, hemp, etc.) or in various resin films such as polyester, polyvinyl chloride, etc. (Of course, the film may not only have a smooth surface, but may also have a rough surface such as a matte finish.)

) is used as a base material, one side of this predetermined side is masked, and then a metal such as aluminum, gold, silver, copper, nickel, etc. is vapor-deposited or plated, or a so-called conductive paint is applied. There is also a method.

Of course, in this case as well, after the base material is uniformly coated, the coating on one predetermined side may be removed.

The porous outer layer composed of the material thus obtained is
It is provided to cover or surround the inner porous elastic member.

On the other hand, the characteristics of the elastic member itself are that it is composed of spongy air bubbles, minute spherical open air cells, or other felt-like members with spaces, and the inside of the elastic member has a continuous structure that can be impregnated with liquid. The shape can be a roller shape or an endless belt shape.

By the way, the porous layer provided on the outermost side of the elastic member has as many fine openings as possible to facilitate the movement of liquid through it.

The outermost layer and the inside of the rotating member of the present invention do not necessarily need to rotate or rotate together.

That is, it is possible to make the interior of the elastic body rotate at a different speed from that of its outermost layer, and the object of the present invention can be distantly achieved by rotating or rotating the interior at a much faster speed than the outermost layer. Ru.

Further, the elastic member can be configured to have a plurality of layers, and the elastic modulus and spatial density of each layer can be changed.

The present invention will be explained in more detail below using examples and drawings for explanation.

FIG. 1 shows a typical embodiment of the rotating member of the present invention.

The rotating member of this embodiment has a roller shape, and its basic structure includes a center roller serving as a rotation axis, an elastic member around the center roller, and an outermost mesh member.

In the figure, a roller-shaped rotating member 1 includes a center roller 2 made of a rigid body such as metal or hard synthetic resin, and an elastic foam 3 made of foamed polyurethane, for example, provided around the center roller 2 as an elastic member. , and a net 4 covering the bubble 3.

The foam 3 is fixed to the center roller 2, and the mesh 4 is supported around the elastic foam 3, so that when the central shaft 2 rotates, the foam 3 and the mesh 4 are integrated. It rotates.

Further, the foam body 3 is made of polyurethane foam having open cells, and it is possible to absorb and squeeze out liquid through the mesh.

As described above, the surface net 4 is a net-like body obtained by weaving or knitting fine fibers.

However, in this case, as shown in the enlarged view of FIG. 2, at least the outermost convex portion of the net-like body is coated with an insulating material made of resin or the like.

In addition, in Fig. 2, 4A is a fiber of a conductive substance,
4B is a part where the insulating material is applied.

Further, as another modification of the net 4, as shown in FIG. 3, it may be a net-like body obtained from fibers in which a part of the fibers made of an insulating material is left and most of the other fibers are covered with a conductive material. .

Incidentally, 4C is the cross section of the insulating material fiber, and 4D is the cross section covered with the conductive material.

Regarding the embodiment shown in the first figure, the field of application is a developing roller of an electrophotographic copying machine.
A mesh value of 60 to 400 meshes is suitable for use.

However, in view of the fact that traces of contact with the mesh may appear on the developed image, or for convenience of use, 180 meshes to 300 meshes are particularly suitable.

By the way, when using a net as in the above embodiment, it is better to use a net made of plain weave, twill weave, or satin weave. It may also be a modified version.

In addition, in the embodiment shown in FIG. 1, the method of laying the net on the foam 3 is such that the horizontal fibers of the net coincide with the rotation axis and the vertical fibers are perpendicular to the rotation axis. However, it is of course possible to arrange the fibers and the rotating shaft at any other angle.

In addition, the number of nets is not limited to one, but two or more can be laid one on top of the other.

As an example of the mesh according to this embodiment, a plain weave nylon mesh plated with 1 to 2 μm of copper on one side has the good conductivity of copper and the appropriate elasticity or flexibility of the nylon mesh. It also showed gender.

Further, those plated with nickel also showed properties almost similar to those described above.

According to studies by the inventors, the film thickness of metal plating is approximately 3.
It should be kept at 0μ, and in order to impart conductivity without damaging the physical properties of the substrate such as nylon, it is approximately 10μ.
It is preferable to set it to below μ.

Instead of metal plating, various conductive paints can be applied.

Examples of the conductive paint include quaternary ammonium-based conductive resin paint, sulfonate-based conductive resin paint, and resin paint in which carbon powder, silver powder, etc. are dispersed.

When a conductive paint is applied, its surface resistivity is approximately 106. It has a Q-m to 1078·m and exhibits a sufficient effect as a counter electrode during development.

Conductive paints are generally soft and have a certain degree of elasticity, so even if they are applied relatively thick, the physical properties of the substrate are unlikely to be impaired.

However, if it is applied excessively, it will block the openings of the net that serves as the base, so a suitable amount should be applied.

The principle of transferring liquid to and from such a rotating member is roughly as follows.

That is, when the rotating member 1 impregnated with liquid is compressed, the liquid in the foam 3 is squeezed out from the weave, and conversely, when the fluid is released from compression and the foam 3 is revived, The liquid on the surface of the mesh 4 is absorbed into the foam 3 through the weave.

Although a typical embodiment of the rotating member of the present invention has been shown above,
Of course, various other configurations are possible.

For example, as in the embodiment shown in FIG. 4, a tubular body having a large number of small holes perforated in the outermost layer may be used.

In FIG. 4, 5 is a tubular body having a large number of small through holes.

In this case, at least the outermost side of 5 needs to be covered with an insulating material.

Such a tubular body 5 can be made by bonding a resin film and a metal film together and then punching a large number of small holes therein, or by using a resin film (after punching a large number of small holes in the resin film), metal is vapor-deposited on one side of the film. After plating or coating with conductive paint, or conversely, drilling a large number of small holes in a film of conductive material such as metal,
An insulating material such as a resin paint is coated on one side of the film (of course, a method may also be used in which the film serving as the substrate is vapor-deposited, plated, or coated, and then small holes are formed therein).

) can be made from a film prepared by

Although the through hole shown in FIG. 4 has a substantially elliptical shape, its shape is not limited, and may be, for example, rectangular, circular, mosaic, or a combination thereof.

Note that in FIGS. 1 and 4, the outermost layer constituting the surface of the elastic member is shown enlarged for convenience of explanation.

When the rotating member shown above comes into contact with the electrostatic latent image carrier, it is estimated that a small amount of latent image charge will transfer to the insulating material provided on the outer surface of the rotating member. In this case, the electrostatic latent image will not be destroyed unless the contact surface between the two is made minute.

On the other hand, in the present invention, since the insulating material is provided as described above, the conductive portion can be easily brought very close to the electrostatic latent image carrier, and the electrode effect allows high-speed development without edge effects. Moreover, it can be done stably.

In addition, the insulating material that is pressed against the electrostatic latent image carrier is generally softer than metal or the like, and has the advantage that there is less risk of scratching the surface of the electrostatic latent image carrier.

By the way, the elastic foam 3 may be made of any material other than the foamed polyurethane used in the embodiment as long as it is capable of absorbing and squeezing out liquid and has appropriate elasticity.

For example, members with spherical open cells or spongy cells such as Bostyrene, polyethylene, vinyl chloride, and nitrile rubber, elastic members made of wool, synthetic fibers, metal fibers, etc., and combinations thereof may be used. is also possible.

In particular, when using fibers for the elastic foam part, the appropriate thickness of the fiber member is about 1 to 20 mm; if it is too thick, it will be difficult to obtain a uniform thickness, and if it is too thin, it will be difficult to obtain a suitable elasticity. I can't do it.

The fiber member is arranged with a uniform thickness around the center roller, and its surface is further surrounded by a porous outer layer as described above to prevent the internally entangled fibers from moving and deforming, and furthermore, the shape of the rotating member is In particular, it also prevents deterioration of the surface condition.

Among these, rotating members using fibers as elastic members are compared with those using foam members made of resin I as elastic members.
The ability to absorb and squeeze out liquid through elastic deformation is extremely excellent.

The reason for this is when comparing cellular members and fiber members,
It can be said that the latter has considerably lower resistance to liquid passage.

Furthermore, it is desirable that the rotating member has excellent mechanical durability against chemicals such as petroleum-based solvents, and can withstand long-term use.

FIG. 5 is a schematic diagram showing a cross section of an embodiment of the pond of the rotating member of the present invention.

In the rotating member 1fζ of this embodiment, the elastic foam 3, which is an elastic member provided around the center roller 2, has an inner layer and a two-layer structure.

The inner layer 3A of the foam 3 is made of foamed polyurethane, and the outer layer 3B is made of metal fiber (included in the foam for convenience). A net 4 made by knitting fibers is laid.

It is also possible to configure the elastic foam 3 of the flexible means 1 into a plurality of layers as in this embodiment, and change the elastic modulus and physical properties of each layer.

In the case of this embodiment, since the outer layer 3B is electrically conductive, it can be used as an electrode roller in combination with the conductivity of the mesh 4. For example, when applied to a developing roller, it can be used in close proximity to an image holding member. Depending on the conductive portion, a developing electrode effect can be obtained by self-biasing, grounding, or applying any bias voltage.

Of course, if the inner layer 3A# is made of a conductive foam member and a metal roller is used as the center roller 2, the roller 2
It becomes possible to apply more voltage.

Furthermore, the effects obtained by configuring the elastic foam 3 into multiple layers and changing the elastic modulus or cell ratio for each layer are as follows.
For example, the balance between the contact pressure and the contact width at the time of contact with the opposing rigid image holding member, or the balance between the contact pressure and the liquid absorption and squeezing effect may be finely adjusted.

In the embodiment shown in FIG. 4, a rotating member 6 is formed to rotate an elastic foam 9 and a mesh 10, which are elastic members, by means of two rotating shafts 7 and 8, and 10 in the figure is an elastic foam. 9 shows a net made of woven resin fibers and partially plated with metal.

As the constituent members of the rotating member 6, substantially the same materials as those explained in the embodiments of FIGS. 1, 4, and 5 can be used. The rotation of the foam 9 can be inhibited by using a material with high frictional resistance on the rotating roller 7.8 side of the elastic foam 9 or by making the surface of the rotating roller 7.8 rough. Can be made smooth.

Next, an embodiment in which the present invention as described above is applied to an actual image forming apparatus will be described below with reference to the drawings.

As an example of an image forming apparatus, a conventional electrophotographic copying machine will be taken as an example, and as a first application example, an example will be described in which the rotating member is applied to a developing roller of a developing unit.

FIG. 5 schematically shows a cross section of the above-mentioned copying apparatus. In the figure, reference numeral 11 denotes a drum-shaped photoreceptor which rotates about a rotating shaft 12 in the direction of the arrow.

Reference numeral 13 denotes a latent image forming means section that forms a latent image in the form of an image on the photoreceptor 11, 14 a developing device section, 15 a transfer means section that transfers the developed image onto a transfer material, and 16 an unnecessary portion on the photoreceptor 11. A cleaning unit for cleaning the developer and erasing unnecessary latent images is shown.

The developing unit 14 is disposed below the photoreceptor 11, and the main components of the developing unit are a liquid tank 18 containing a developer 17 and a liquid tank 18.
It has a developing roller 19 that is partially immersed in the developer 17 therein, and a squeezing roller 20 that is in pressure contact with the developing roller 19.

As described in FIGS. 1 and 4 above, the developing roller 19 includes a center roller 21, an elastic foam 22 made of foamed polyurethane provided around the roller 21, and a mesh endlessly surrounding the foam 22. It has 23.

The network 23 is constructed as described in detail above.

The center roller 21 of the developing roller 19 is 1 (not shown).
The net 23 is supported so as to rotate in the same direction and at the same speed at the contact portion with the photoreceptor 11 by receiving rotational force from a drive source.

A squeezing roller 20 is in pressure contact with the developing roller 19 in the developer 17, and the action of the roller 20 replaces the developer in the air bubbles 22.

As for the installation mechanism of the center roller 21, when not performing development or when stopping the entire apparatus, the center roller 21 is
3 and the photoconductor 11, or may also have a function of releasing the pressure contact state with the aperture roller 20.

On the other hand, 26 is a power supply section, 27 is a voltage generation section of the power supply section 26,
X and Y indicate contacts on the voltage generation side, and Zl and Z2 indicate contacts on the ground side.

Further, 28 and 29 are conductive wires connecting the power supply section 26 and the conductive section of the developing roller 19.

In this embodiment, depending on the characteristics of the latent image on the photoreceptor 11 and the characteristics of the developer, an appropriate voltage is applied to the mesh 23 on the surface of the developing roller 19 or grounded. Desirable development conditions can be obtained by applying an appropriate potential.

Note that the contact point connecting the power supply unit 26 to the developing roller 19 may be placed directly on a part of the net 23 (24 shown in the figure), and both the bubble 22 and the center roller 21 may be made of a conductive material. Therefore, it may be directly applied to the center roller 21.

(Illustration 25) On the other hand, the photoreceptor 11 and the developing roller 1 in FIG.
If you enlarge a part of the contact area with the net 23, it is as shown in FIG.
A is made of an insulating material, and the other part 23B is generally made of a conductive material.

Next, the developing process to which the present invention is applied will be described in further detail with reference to FIG. 9, which schematically shows a partially enlarged cross section of the developing unit 14 shown in FIG. 7.

As shown in the figure, since the developing roller is partially immersed in the developer, the developer 17 permeates into the air bubbles 22 through the net 23, and the permeated developer is transferred to the photoreceptor by the rotation of the transparent roller 19.
The image is transported to the development position No. 1.

At the developing position, the photoreceptor 11 and the developing roller 19 are arranged so as to be in pressure contact with each other as described above. When compressed onto the photoreceptor 11 (area B in the figure),
The bubbles 22 are squeezed out through the net 23 to the outside of the roller 19.

As a result, a large amount of developer with a high concentration is normally supplied to the vicinity of the photoreceptor 11 (areas A and B in the figure) during development.
As a result, the developing time can be shortened, and the developing device can also be made smaller.

Further, during the above-mentioned development, since the developing roller 19 has elasticity, when it comes into contact with the photoreceptor 11, it forms a nip that makes surface contact with a width perpendicular to the rotation direction of the photoreceptor 11. It acts as a uniform developing agent.

This provides a high-density developer to the latent image on the photoreceptor, and enables good development without unevenness or missing parts of the developed image.

Furthermore, depending on the developing method using the present invention, the developing roller 1
9 and the color sensitive member 11, the surface of the developing roller 19 (or the contact surface) allows the developer to be sufficiently squeezed out from inside the developing roller for the above-mentioned reasons.

As a result, the latent layer on the photoreceptor 11 is developed with sufficient developer, so that a good developed image can be formed.

Also, when looking at the flow of the developer during development, the flow is gentle, the collision of the flow against the photoreceptor 11 is small, and the flow in the nip direction is actually so small that it can be ignored.
Even in the above points, the latent image, developed image, etc. are not disturbed.

Further, when the developing roller 19 comes into contact with the photoreceptor 11, part of the developer impregnated in the air bubbles 22 is squeezed out onto the photoreceptor in the opposite direction to the rotation direction ( In the figure, especially area A).

Therefore, immediately after the contact pressure with the photoconductor 11 is released, the bubble 22 is revived from the deformed state due to compression, and at this time, the bubble 22 is impregnated with a small amount of developer, so it is not suitable for use as a concubine. The ability to absorb liquids is restored (area C in the diagram).

This absorption capacity has the effect of absorbing unstable developer on the carrier at the end of the development process in liquid development.

The above-mentioned absorption capacity; coupled with the size, surface area, and surface tension of the developing roller 19, the carrier liquid, which is the main component of the unstable developer that tends to remain on the surface of the photoreceptor 11 immediately after development, and the unstable Toner particles are absorbed through the mesh 23 in the roller 19.

As a result, only the toner particles 30 adhering mainly to the latent image remain on the photoreceptor 11 and reach the transfer means section (not shown).

By performing liquid development using the rotary member of the present invention in this manner, it is also possible to obtain the effect of squeezing out unstable developer, which has been a difficult problem in liquid development technology.

Note that in FIG. 9, the points at the developing roller 19 and the developing section schematically indicate the density of toner particles in the developer.

The developing roller 19 that has passed through the developing section is immersed in the developer again in preparation for the next developing cycle, and due to the action of the squeezing roller 20, the toner concentration is reduced by the development, and the developing roller 19 is impregnated in the bubbles 22. Replace and stir the agent.

The various effects in the development process described above include impregnating a latent image bearing member such as a photoreceptor with developer, squeezing out the developer by elastic deformation, and reviving the developer. This is achieved by using a rotating member that absorbs the

Further, the rotating member of the present invention is one that does not destroy the latent image on the latent image carrier or disturb the developed image, that is, does not cause deformation on the contact surface with the carrier, and - The force changes elastically in a direction substantially perpendicular to the contact surface.

In the above embodiments, the latent image carrier has rigidity, taking the photoreceptor as an example, but it may of course have appropriate elasticity.

By the way, when the developing roller and the latent image carrier come into contact with each other, it is impossible to squeeze out and absorb the developer unless at least the developing roller is elastically deformed.

Furthermore, if a felt-like or spongy-like elastic body is directly used as the above-mentioned developing roller, the latent r-shaped material on the carrier and the elastic body come in strong planar contact with each other, making it impossible to supply a sufficient amount of developer. This causes the image to become extremely thin.

However, these problems can be solved by using the rotating member of the present invention as a developing roller.

FIG. 10 shows an embodiment in which the rotary member of the present invention is arranged in an endless bevel shape and is applied to a developing unit of a color copying apparatus.

In the figure, 11 is a drum-shaped photoreceptor that rotates in the direction of the arrow, 31 is a yellow developer, 32 is a magenta developer, 33 is a cyan developer, and 34 is a black developer. A liquid developer is used.

Here, the configuration will be explained using a yellow developing device as an example.

Figure) In this case, 35 is a liquid tank that absorbs yellow developer 36, and a belt-shaped rotating member 37 is suspended from two rotating shafts 38 and 39 so that a part of the yellow developer 36 is immersed in the yellow developer 36. .

The developing belt 37 is substantially the same as the rotating member described in FIG. 6 above.

When the developing device 31 is operated, the developing device 31 is raised by a conventionally known driving means 40 such as a plunger, and the developing belt 37 is brought into contact with the photoreceptor 11, thereby forming the contact nip.

It goes without saying that development may be performed by lifting only the developing belt 37 without lifting the entire developing device.

As described below, the effect of using the elastic member in the form of a belt is that the developing area can be made smaller, so that it is possible to This is particularly effective.

However, of course, it can also be used in a developing device that performs monochrome development.

As described above, the rotating member of the present invention has the function of absorbing and squeezing out the developer, and also has the pressure contact position t when it comes into heavy contact with the latent image carrier.
It is possible to satisfactorily develop the latent image on the carrier by means of an elastic member that does not cause deformation in the direction of the trowel contact surface but is elastically deformed in the direction perpendicular to the contact surface.

Furthermore, the rotating member of the present invention supplies sufficient developer to the latent image on the carrier, and since the developer does not wash away the developed image, the original image can be reproduced extremely faithfully and a good quality can be obtained. Enables development.

Furthermore, when the rotating member leaves the carrier, it absorbs the unstable developer on the carrier, so that development can be completed leaving only the toner particles on the carrier.
In addition, since there is no need for a means for squeezing out excess developer on the carrier, it is easy to downsize the developing unit, which also leads to downsizing of the entire image forming apparatus and reduction in manufacturing cost.

That is, by applying the rotating member of the present invention to the developing unit, most of the drawbacks of the conventional liquid developer technology can be eliminated.

Note that in the above-mentioned embodiment), the developing device in this case is an example in which one developing belt is disposed in each developing device; 2. In general, one developing belt performs a sufficient function, but this is not limited to this example. There's no need.

Further, each developing device may be provided with a mechanism for accommodating replenishing developer, a concentration detecting means, a stirring means, etc., but these are not shown.

Although not shown, it is also possible to obtain good development results by adding a voltage application means as shown in the seventh illustrated example.

By the way, the rotation or rotation of the developing belt material is either operated at substantially the same speed and in the same direction on the contact surface with the latent image carrier, or is driven by a driving force from a drive source, or by the above-mentioned carrier. This may be caused by friction with the body.

The shape and structure of the developing belt can be modified by combining the shapes and structures of the flexible means described in the above embodiments.

For example, the shape can be freely combined, such as whether to use a foam (1 hole, 1 hole) or a foam, but the development speed, developer characteristics, latent image carrier characteristics, etc.
In view of this, we will combine the appropriate methods.

Regarding the latent image carrier, as mentioned above, the carrier is not limited to a photoreceptor, but may be an electrostatic recording material or any other material that supports an electrostatic latent image, and its formation is It is applicable to drum-shaped, sheet-shaped, wave-shaped members, etc.

Next, as a second application example, a case where the rotary member of the present invention is applied to a liquid squeezing roller of a developing unit will be described with reference to FIGS. 11 to 13.

First, FIG. 11 schematically shows a cross section of the developing unit 41. In the figure, 42 is a drum-shaped photoreceptor that rotates in the direction of the arrow, and a developing device that also acts as an electrode is located at the bottom of the photoreceptor. A tray 43 is located therein, to which developer is guided by pump means 44 and a conduit 45.

A latent image formed by a latent image forming means (not shown) is developed in the developer section 41 and then transferred to a transfer paper or the like in a transfer section. Since some carrier liquid remains, there is no need to worry about squeezing out the excess carrier liquid before the transfer process.

This squeezing technique uses a corona discharger,
Some use a roller that rotates in close proximity to the photoreceptor, or a roller that has the function of absorbing and squeezing out the sponge paper.

The rotating member of the present invention can also be applied as these liquid squeezing means, and its effects are great (it becomes a new liquid squeezing means that solves the problems of the prior art).

When trying to squeeze out the excess developer on the photoconductor using a liquid squeezing means using a conventional sponge roller, the sponge itself seems to be able to squeeze the liquid well, but the following problems arise. However, there are some difficulties in developing and actually putting this into practical use.

That is, description of the characteristics of the present invention as the above-mentioned developing roller! As mentioned above, when a conventional latent image using a mere elastic member is pressed against a photoreceptor, the elastic member, which is soft not only inside but also on the surface, moves in the tangential direction of the photoreceptor at the nip when the elastic member is pressed. At the same time, the contact surface forms a substantially smooth plane.

Therefore, the elastic member rubs or crushes the toner particles adhering to the latent image during development, thereby disturbing the developed image.

Furthermore, the elastic member made of only a general foam is placed in pressure contact with the photoreceptor (the air bubbles and spaces on the iron surface and the vicinity are collapsed,
Sufficient fluid absorption becomes impossible during resuscitation.

In addition, foamed members tend to foam non-uniformly during formation, which means that the excess carrier liquid on the photoreceptor is uniformly removed when the liquid is squeezed.
This leads to the problem of not being able to narrow it down.

The present invention solves these problems of conventional liquid squeezing means, and the liquid squeezing speed can be improved compared to other liquid squeezing means.

The rotating member of the present invention, which serves as a liquid squeezing roller, is disposed in pressure contact with the photoreceptor 42 between the developing device section 41 of the photoreceptor 42 and a transfer means section (not shown).

In the figure, reference numeral 46 denotes a liquid squeezing roller which is a rotating member of the present invention, and its structure is the same as that shown in FIG.
It has a center roller 47 that rotates in synchronization with the roller 2, an elastic foam 48 provided around the center roller 47, and a mesh 49 on the surface.

On the other hand, a rotating roller 50 for squeezing out the absorbed developer is in pressure contact with a part of the liquid squeezing roller 46, and the roller 50 is rotated in synchronization with the liquid squeezing roller 40 by rotation of a rotating shaft 51.

Note that the roller 50 may be formed of a conductive material such as metal, and may be configured to be grounded as shown at 52 in the figure.

Therefore, even if a part of the latent image on the photoreceptor 42 is transferred (on the surface of the liquid squeezing roller 46), it can be erased to prevent an adverse effect on the subsequently developed image.

Incidentally, 53 is a conductor.

A cleaning blade 54 is in pressure contact with the roller 50, and the blade 54 also serves to guide the squeezed developer into the liquid tank 55 of the developing device.

That is, the developer 56 in the liquid tank 55 reaches the photoreceptor 42 by the pump means 44, and is further circulated via the liquid squeezing roller 46 and the rotating roller 50.

Here, the action of the liquid squeezing roller 46 will be explained in detail with reference to a partially enlarged view of the liquid squeezing part in FIG.
In this image of adhered toner particles, 58 indicates a carrier liquid.

The liquid squeezing process starts when the carrier liquid comes into contact with the liquid squeezing roller 46 while thickly covering the photoreceptor 42 .

A liquid squeezing roller 46 that rotates at the same peripheral speed as the photoreceptor 42
rotates while contracting and deforming in the normal direction of the photoreceptor 42 to point D on the line connecting the rotation axis of the photoreceptor 42 and the rotation axis of the liquid squeezing roller 47 .

During this time, only a small portion of the net-like body 49 is in relatively stationary contact with the toner particle image on the photoreceptor 42, so there is no need to worry about the toner particle image being crushed or rubbed. It does not disturb the image.

In addition, the population [from rule E, the elastic foam 4 up to the above point
8 rotates while elastically contracting and deforming the bubbles, during which time some of the carrier liquid 58 on the photoreceptor 42 seeps into the bubbles 48 through the net-like body 49, and some of it also penetrates into the mesh of the net-like body 49. After being retained and the other part accumulating on the entrance side E,
It soaks into the bubble 49.

That is, even if the surface of the liquid squeezing roller 46 is in pressure contact with the opposing member, the surface is not deformed and the passage opening is not crushed, so that the carrier liquid can be transferred from point D to point F.

With this, the liquid squeezing roller 46 that has passed the point D is deformed in the direction of resuscitation deformation.

During this time, since the liquid squeezing roller 46 always has a passage opening on its surface, the carrier liquid is forcibly absorbed into the bubbles 48 immediately after passing the point D.

Therefore, most of the carrier liquid on the photoreceptor 42 can be absorbed on the exit side F.

After the liquid squeezing roller 46 separates from the photoreceptor 42, it then comes into pressure contact with a rotating roller 50 for squeezing out the developer.

A rotary roller 50 that rotates in pressure contact with the liquid squeezing roller 46 in the same direction as the liquid squeezing roller 46 at the pressure contact position causes the developer containing the carrier liquid absorbed from the surface of the photoreceptor 42 to be applied to the inlet side G between the roller 50 and the liquid squeezing roller 46 . 58 are accumulated as shown in the figure.

As the amount of accumulated developer 58 increases, it exceeds the rotating roller 50,
Further, the liquid falls through the upper side of the cleaning blade 54 for the roller 50 into a liquid tank (not shown).

Then, the liquid squeezing roller 46 reaches the exit side H in a state in which the developer has been squeezed out by the rotating roller 50.

In the above embodiment, the rotation direction of the rotating roller 50 and the rotating shaft of the liquid squeezing roller 46 is set to be opposite to that of the liquid squeezing roller 46. It is also possible to rotate.

FIG. 13 shows an embodiment in which a rotating roller for squeezing out the developer is provided close to the entrance side E.

In the figure, 59 is a rotary roller, 60 is its rotating shaft, 61 is a blade for cleaning the roller 59, and 62 is a guide means for transferring the developing solution accumulated on the inlet side I of the two rollers to a liquid (not shown). It consists of a plate member for guiding the inside of the tank.

Both the examples shown in FIGS. 12 and 13 show good results in terms of liquid absorption ability and liquid absorption rate ability.

Further, the liquid absorption capacity can be adjusted by selecting the material of the bubble 48 or adjusting the pressure force with which it is pressed against the photoreceptor.

Although the apparatus of the embodiment uses a photoreceptor as an example, it is of course applicable to liquid development of latent images formed on other insulators.

Furthermore, the shape of the latent image carrier may be an endless belt or a plate.

By the way, the liquid squeezing roller can also be used as a liquid flow stopper having the function of preventing the developer or IJ-ning liquid flowing from the upper part of the drum-shaped photoreceptor from flowing below a predetermined position.

Next, as a third application example, a case where the present invention is applied to a cleaning roller of a cleaning means section, the first embodiment will be explained with reference to FIGS. 14 and 15, and the second embodiment will be explained with reference to FIG. 16. This will be explained with reference to FIG.

First, a first embodiment shows a case where the central axis of the rotating member of the present invention used for cleaning and the rotating axis of the photoreceptor are rotated in the same direction.

In FIG. 14, reference numeral 63 denotes a drum-shaped photoreceptor which rotates about a central axis 64 in the direction of the arrow.

A cleaning hanger 65 disposed above the photoreceptor 63 is a rotating member according to the present invention, and removes toner particles remaining on the photoreceptor 63 after transfer.

The photoreceptor cleaned by the cleaning roller 65 is
For the next image forming process (further rotate in the direction of the arrow).

By the way, the configuration of the cleaning roller 65 may be as shown in FIG. 1 or FIG.
The configuration of the illustrated example will be described.

66 is a rotating shaft of the cleaning roller 65, 67 is an elastic foam, and 68 is a net-like body.

The cleaning roller 65 and the photoreceptor 63 move in opposite directions on their pressure contact surfaces, and the friction caused by the movement scrapes off toner particles and the like on the photoreceptor 63, thereby performing cleaning.

In the drawing, reference numeral 69 and 70 denote conduits that supply the developer in a developer tank (not shown), which has been pumped up by a pump 71, to the cleaning pit roller 65.

When the above developer supply is stopped, toner particles may be removed from the cleaning roller 65 if the device has been out of operation for a long time.
This is particularly necessary because the surface of the photoreceptor is easily damaged due to solidification and rubbing between the photoreceptor and the photoreceptor 63.

In the cleaning process according to this embodiment, when the main switch of the entire apparatus is turned on, the pump 71 is activated, and an appropriate amount of developer is used as a cleaning liquid to clean the cleaning roller 6.
Supply to 5.

After the roller 65 is sufficiently wetted, the photoreceptor 63 and the roller 65 are rotated.

The present invention provides various effects not found in the conventional application of simple sponge rollers.

That is, on the surface of the cleaning roller 65 of this embodiment,
Since the conductive net-like body 68 is present, a voltage is applied through the conductive net-like body 68, and the effect of electrically attracting and collecting the toner is significant.

For example, a bias voltage having a polarity opposite to the potential of the toner is applied to the net-like body 68 from a voltage source (not shown), and when the net-like body 68 is brought into pressure contact with the photoconductor 63, the toner is applied to the photoconductor 63 between the two. direction of pulling away from (generates an electric field)

In addition, since the nip portion is in a wet state when the two are pressed and rubbed together, the toner can be completely removed.

Cleaning is performed by rubbing the toner particles under a wet condition at the nip portion as described above, and absorbing the removed toner particles into the roller 65 at a position where the roller 65 separates from the photoreceptor 63.
Next, at a position where the roller 65 contacts the photoreceptor 63, the developer containing the removed toner particles is squeezed out.

By the way, if the surface of the roller 65 is equal to or less than 250 meshes, toner particles can be prevented from blocking the openings on the surface of the roller 65.

When the cleaning means is operated, as shown in the figure, the developer 72 accumulates on the photoreceptor 63 which first comes into contact with the cleaning roller 65, and begins to flow downward as the photoreceptor 63 rotates.

In the figure, reference numeral 73 denotes a liquid flow stopper, which acts to prevent the developer 72 that has started flowing from reaching the latent image forming area of the photoreceptor 63. The member 73 is as shown in FIG. It is even better if it is arranged obliquely to the horizontal axis of the photoreceptor 63 (76 in the figure).

As a result, the developer that has reached between the liquid flow member 73 and the photoreceptor 63 reaches the groove 74 at the end of the photoreceptor 63 due to the inclination of the member 73 and returns to the liquid tank (not shown).

In FIG. 15, reference numerals 74 and 75 indicate concave grooves, which are provided at both ends of the photoreceptor in the illustrated example, but the grooves may be provided as needed and are not essential components.

Further, 64 is the rotation axis of the photoreceptor 63, 77 is a two-dot broken line indicating the latent image forming area, and 76 is the liquid flow stopper and the photoreceptor 6.
This is a two-dot broken line indicating the contact position with No. 3.

The effects obtained by using the present invention compared to the case of using a conventionally used simple sponge roller are as follows.
As mentioned above, sufficient wetting can be achieved on the pressure contact surface even during pressure contact sliding, and in combination with the electric field action, toner particles can be removed even more easily.

Furthermore, compared to using a simple sponge roller,
Since there is no elasticity unevenness or hardness unevenness in the roller structure, more uniform and even cleaning is possible.

It should be noted that the conduit 69 of the above embodiment does not necessarily need to be provided in the position shown in the figure if the conduit 70 functions satisfactorily.

Next, FIG. 16 shows another embodiment of the stone rack (this will be explained here).

In this embodiment, the rotational relationship between the cleaning roller 65 and the photoreceptor 63 is reversed from that shown in FIG. 14 above.

That is, the roller 65 and the photoreceptor 63 are arranged so that they move in the same direction at a position where they are in pressure contact with each other.

The relationship between the rotational speeds of the other is such that the circumferential speed of the roller 65 is higher or lower than the circumferential speed of the photoreceptor 63, and the photoreceptor 63 and roller 65 slide against each other due to their relative speeds. Configure them so that they are compatible with each other.

In the cleaning process using the cleaning means configured as described above, the pump 71 is activated by turning on the main switch of the entire apparatus, similar to the embodiment shown in the fourteenth figure.
An appropriate amount of developer is pumped up from a liquid tank (not shown) by a pump 71, and then delivered to a cleaning roller 65 through conduits 78 and 79.
supply to

After the toner particles that have solidified during the stop are moistened and become sufficiently soft, the photoreceptor 63 and cleaning roller 6
Rotate 5 to begin the cleaning process.

During cleaning, the roller 65 is elastically deformed toward the conduit 78 as shown in the figure (developer oozes out from this and wets the toner particles on the photoreceptor to be cleaned).

Thereafter, for the same reason as in the case of the fourteenth illustrated example, the photoreceptor 63 is moved to the roller 65 in a state where the elastic foam 67 is wet.
Clean by rubbing.

The cleaning roller 65 released from the pressure contact state absorbs the developer and removed toner particles from the photoreceptor 63 by resuscitation, reaches the position of the conduit 78 again, and converts the absorbed toner particles into developer. To squeeze out the same.

When installing the cleaning roller 65 on the photoreceptor 63, it should be installed obliquely to the rotation axis of the photoreceptor 63, as shown in FIG. good.

As a result, the squeezed out developer flows into the groove 74 of the photoreceptor 63 along the slope.

In this embodiment, unlike the embodiment shown in FIG. 14, there is no need to provide a liquid flow stopper for preventing the developer from flowing down to the latent image forming position, resulting in a simple structure.

If no liquid should be present on the photoreceptor 63 after cleaning, the cleaning roller 6
5, the blades may be arranged as in the embodiment shown in FIG.

Also, conduit 79 is not necessarily secure if conduit 78 can supply sufficient liquid to rollers 65.

Further, in this embodiment, the cleaning roller 65 is installed at an inclined position from the uppermost position of the photoreceptor 63 to the latent body forming position, and is selected in particular at a position where the developer accumulated on the conduit 78 side does not flow out to the transfer side.

In the above description, only the case where the rotating member illustrated in FIG. 1 is used has been described, but it goes without saying that other rotating members based on the present invention can be widely applied.

Further, the illustrated embodiment may be modified so that a voltage suitable for erasing the latent material on the photoreceptor can be applied to the surface of the cleaning roller, if desired, at the same time as cleaning the toner.

On the other hand, the side to be cleaned may be not only the photoreceptor but also an insulating member for transferring other latent materials as in each of the above embodiments, and the shape is not limited to a drum-like one.

As described above, the present invention can be widely applied as a developing means, a liquid squeezing means, a liquid flow+Ir means, and a cleaning means in an image forming apparatus using a liquid.

When the present invention was used in each application example, it was possible to obtain various effects that could not be obtained when a conventional elastic member such as a simple sponge was used.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional perspective view showing an embodiment of the present invention;
FIGS. 2 and 3 are partially enlarged explanatory views of the first illustrated embodiment, FIGS. 4 to 6 are suggestive views showing other embodiments of the present invention, and FIG. 7 is a developing device in a copying machine. FIG. 8 is a partially enlarged explanatory view of the example shown in FIG. 7, and FIG. 9 is an enlarged view of a developing device showing an example of the developing process shown in FIG. 7. FIG. 10 is another application example of the present invention, and shows a partial cross section of a copying machine. Further, FIG. 11 is an enlarged cross-sectional view of the developing device for explaining the liquid squeezing part, FIGS. 12 and 13 are partial enlarged cross-sectional views of examples of the liquid squeezing roller, and FIGS. 14 and 16 are respectively , an example of application of the present invention to a cleaning device, and FIG. 15 is a cross-sectional view of the cleaning means section, and FIG. The figure is an explanatory diagram showing a method of installing the cleaning roller in FIG. In the figure, 1, 6... Rotating member, 2... Center roller, 3°9.22, 48.67... Elastic foam, 3A
...Inner layer, 3B...Outer layer, 4A...Conductive fiber, 4B...Insulating material, 4C...Insulating material fiber, 4D...
... Conductive coating, 4.10, 23, 49, 68... Reticular body, 23A... Insulating part, 23B... Conductive part, 5.
... Porous surface layer, 7°8 ... Rotating shaft, 11,42.6
3...Photoreceptor, 14°41...Developer section, 18,3
5.55...Liquid layer, 19...Developing roller, 17,3
6,56,58.72...Developer, 20,50.59
... Squeezing roller, 21 ... Center roller, 24, 25
...Roller electrode, 26...Power supply section, 27...Voltage source, 28,29.53...Conducting wire, 38.39,47,
51.60.66...Rotating shaft, 46...Liquid squeezing roller, 65...Cleaning roller, 54.6'l...
・Blade, 62... Guide means, 44° 71... Pump, 69, 70, 78. 79... Conduit, 73...
Liquid flow stopper.

Claims (1)

[Claims] 1 A rotating member having a porous elastic layer that allows liquid to pass through, squeezes out liquid when compressed, and absorbs liquid when restored from the compressed state, and among the aspects of this rotating member, A rotating member for an image forming apparatus, characterized in that at least a surface that can come into contact with another member is insulative, and most of the outer periphery is configured to have an electrode effect.