JPS5834832B2 - Flexible member for image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flexible member used in an image forming apparatus, and more particularly to a flexible member applied to a device that handles liquids such as developer and cleaning liquid in an image forming process. .

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 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 in 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 the unevenness of the cell particle size Q) in the cell member,
Because the size and shape of bubbles on the surface are uneven,
When pressed against a rigid surface, narrow areas or spot-like contact irregularities occur.

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 above-mentioned elastic roller comes into pressure contact with a rigid member, the contact pressure may be uneven, or the air bubbles on the roller surface may be collapsed at the nip, and the elastic roller may not be able to maintain the uniformity of liquid that was originally intended. absorption or expression becomes impossible.

Additionally, when such an elastic roller is used as a developing means, it is desirable that at least the surface thereof be electrically conductive.

This is because it enables high-speed development 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 and plastic deformation will occur more easily, and the mechanical strength will further decrease. It is pointed out that the liquid absorption and squeezing effects are poor due to unevenness.

On the other hand, with the latter method, the surface of the elastic roller is covered with a rigid material, making it difficult to obtain the appropriate flexibility desired for the elastic roller.

That is, if the roller surface is covered with a metal mesh, it is difficult to recover from the deformation after pressure contact, and surface deformations such as dents and wrinkles remain.

As a result, uneven contact with the mating member occurs, making it impossible for the elastic roller to uniformly absorb and squeeze out the liquid as originally intended.

SUMMARY OF THE INVENTION The main object of the present invention is to provide a versatile flexible member that solves the problems of conventional flexible members (eg, elastic rollers).

Furthermore, another purpose is to at least satisfy the electrical conductivity of the surface, to enable uniform contact at the nip portion and sufficient movement (transfer and reception) of liquid on the contact surface, and further to make it possible to have a surface that is the same as the opposing rigid member. The object of the present invention is to provide a flexible member that does not press the surface of the rigid member into an unfavorable state when rotated or rotated at a circumferential speed.

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 surplus developer on the carrier after development, a cleaning means for the carrier, etc. The object of the present invention is to provide a roller-shaped or endless belt-shaped flexible member that can be handled.

An object of the present invention is to provide a flexible member for an image forming apparatus, the outer peripheral surface of which is covered with a porous layer made of a material made of a base coated with a conductive substance. achieved.

In other words, the flexible member for an image forming apparatus of the present invention has an electrically conductive surface relative to the opposing rigid image holding member,
In addition, it relates to a roller or an endless belt-like means that elastically deforms in a direction relative to the above member, absorbs and squeezes out liquid by elastic deformation accompanied by spatial deformation, and also makes contact at a pressure contact position when pressing against the image holding member. An elastic member that does not deform in the plane direction but elastically deforms in the direction perpendicular to the contact surface has a porous surface layer on the outermost side made of a material made of a base coated with a conductive substance. The flexible member is a roller-shaped flexible member provided around a roller, or the elastic member is configured in an endless belt shape and is suspended around a plurality of rotating shafts.

In the present invention, the material for forming the porous surface layer will be explained below.

That is, the base material (or substrate) is a woven or knitted fabric of synthetic resin fibers or natural fibers (for example, nylon, Tetron, vinylon, acetate, cotton, silk, hemp, etc.),
Alternatively, various resin films such as polyester and polyvinyl chloride may be made with a large number of small holes.

Of course, the film does not have to have a smooth surface, but may have a rough surface such as a satin finish.

All of these belong to insulating materials, but when forming the surface layer, other than the conductivity of the flexible tone tuner according to the present invention, other surface materials as described above must satisfy X. I can do it.

Furthermore, in the present invention, such a substrate is coated with various conductive substances.

For this purpose, aluminum, gold, silver,
There are methods such as vapor deposition of metals such as copper and nickel, plating, and coating with so-called conductive paint.

A porous layer made of the material thus obtained is provided to cover or surround another elastic member.

On the other hand, the characteristics of the elastic member itself are that it is composed of spongy (sponge-like) bubbles, minute spherical open cells, or other members with spaces like felt, and 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 is
It has many fine openings so that liquid can freely pass through it.

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

That is, the inner part of the elastic body can be rotated at a different speed than the outermost layer, and the object of the present invention can also be achieved by rotating or rotating the inner part at a much higher speed than the outermost layer. .

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 flexible member of the present invention.

The (IJ flexible member) of this example has a roller shape, and has a basic structure consisting of a central aperture serving as a rotation axis, an elastic member around the central aperture, and a metal-coated fiber mesh located on the outermost side. There is.

In the figure, a roller-shaped flexible 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 polyurethane foam, 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 coated with a conductive substance.

The principle (abbreviated) of the transfer of liquid by such a flexible member is as follows.

That is, when the flexible member 1 impregnated with liquid is compressed, the liquid in the foam 3 is squeezed out from the seven weave portions, and conversely, when the foam 3 released from compression is revived, The liquid on the surface of the net 40 is absorbed into the bubbles 3 through the woven portion.

In this embodiment, if 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 as the mesh 4.

However, since traces of the mesh may appear on the developed image, or for convenience of use, 180 to 300 meshes are appropriate.

By the way, when a net is used as in the above embodiment, it is not only possible to use a plain weave, twill weave, or sash weave net, but it is also possible to use a net made by pressurizing and deforming the fabricated net.

In addition, in the embodiment shown in FIG. 1, the fibers in the horizontal direction of the net coincide with the axis of rotation, but the method of laying it on the foam 3 is such that the fiber axis and the axis of rotation are at an angle. Of course it's fine.

Furthermore, 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 net according to this embodiment, a plain weave σ-no nylon mesh plated with copper to a thickness of 1 to 2 μm has the good conductivity of copper and the appropriate elasticity or flexibility of the nylon mesh. It also showed gender.

Further, the nickel-plated material also exhibited the same properties as Y described above.

According to studies by the inventors, the film thickness of metal plating is approximately 3.
The thickness should be kept at 0μ, and is preferably about 10μ or less in order to impart conductivity without impairing the physical properties of the substrate such as nylon.

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.

A net coated with such a conductive paint has a low surface hardness and is highly unlikely to scratch the latent image bearing surface to which it is pressed, such as the surface of the photoreceptor.

Also, in terms of conductivity, the surface resistivity is about io 6 Ω·α to 10 7 Ω·α, and exhibits a sufficient effect as a counter electrode during actual use.

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 applied in excess, the openings of the mesh serving as the base will be blocked, so the amount should be kept at an appropriate level.

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

In the present invention, the outermost layer that covers or surrounds the elastic member has a conductive surface, a through hole that does not cut off the elastic member inside and the outside, and furthermore, the outermost layer covers or surrounds the elastic member. For example, any rigid member may be used as long as it is flexible in the direction perpendicular to the surface in contact with the latent image carrier and the through hole at the contact surface is not blocked when the contact surface is made.

Therefore, the outermost layer may be not only a net-like body as described above, but also a plate-like body having a large number of small holes as in the embodiment shown in FIG.

In FIG. 2, 5 is a tubular body made of a resin film with a large number of small through holes and coated with a conductive material.

As described above, a variety of methods can be used to form the conductive material coating, such as vapor deposition, plating, and coating.

Note that it is also possible to prepare a resin film coated with a conductive substance in advance, punch a large number of through holes therein, and then apply the film as the outermost layer.

Although the through hole shown in FIG. 2 has an 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 2, the outermost layer constituting the surface of the elastic member is shown in an enlarged manner.

Since the surface layer of the flexible member in each of the above embodiments is conductive, it can be grounded to remove unnecessary charges transferred to the means.

Therefore, the negative influence on the development result caused by the charge on the means is eliminated.

It is also possible to apply a voltage, and it is also possible to improve the development result by applying a bias voltage during development.

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 made of polystyrene, polyethylene, vinyl chloride, nitrile rubber, etc. with spherical open cells or spongy σ cells, other elastic members made of wool, synthetic or metal fibers, and combinations thereof may also be used. It is possible.

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

The fibers are arranged in a uniform thickness around the middle +1iiD-ra,
The surface of the flexible member is surrounded by a conductive porous layer as described above to prevent the internally entangled fibers from moving and deforming, and furthermore to prevent the shape, particularly the surface condition, of the flexible member from being destroyed.

Among them, flexible members using fibers as elastic members are compared to those using resin foam members as elastic members,
The ability to absorb and squeeze out liquid through elastic deformation is extremely excellent.

One reason for this difference is that when comparing a cell material and a fiber material, the latter has considerably lower resistance to liquid passage.

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

FIG. 3 is a schematic diagram showing a cross section of another embodiment of the flexible member B1 of the present invention.

In the flexible means 1 of this embodiment, the elastic foam 3, which is an elastic member provided around the center row 22, has a two-layer structure, an inner layer and an outer layer.

The inner layer 3A of the foam 3 is made of foamed polyurethane, and the outer layer 3B is made of metal fibers (included in the foam for convenience), and the surfaces of these elastic foams 30 are further coated with metal-plated resin fibers. It is composed of a net 4 made by knitting.

It is also possible to configure the flexible member 10 and the elastic foam 3 into a plurality of layers as in this embodiment, and change the elastic modulus and physical properties of each layer.

In this case, 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, and for example, when applied to a developing roller, it is placed close to an image holding member. By using the conductive portion, a developing effect can be obtained by self-biasing, grounding, or applying any bias voltage.

Of course, if, for example, a conductive foam member is used for the L-oriented layer 3A and a metal roller is used for the center roller 2, the [l-ra 2
It becomes possible to apply more voltage.

In addition, the elastic foam 3 is composed of multiple layers, and the effect obtained by changing the elastic modulus or cell ratio for each layer is to improve the balance between contact pressure and contact width when contacting with a rigid image holding member facing in the direction. Or contact pressure and liquid 0) absorption and squeezing effect 0)
One example is making subtle adjustments to balance, etc.

The embodiment shown in FIG. 4 has a configuration in which two rotating shafts 7 and 8 rotate an elastic foam 9 and a mesh 10, which are elastic members.
(2) A flexible member 6 is formed, and 10 in the figure indicates a net made by knitting metal-plated resin fibers provided on the surface of the elastic foam 9.

As for the constituent members of the flexible member 6, materials similar to those described in the embodiments of FIGS. 1 to 3 may be used. The rotation of the foam 90 is made smooth 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 7.80 rough. be able to.

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

A conventional electrophotographic copying machine is taken as an example of the image forming apparatus 2, and as a first application example, an example will be described in which the flexible member is applied to a developing roller of a developing unit.

FIG. 5 schematically shows a cross section of the copying apparatus σ), in which 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 for forming a latent image in the form of an image on the photoreceptor 11, 14 a developing device section, 15 a transfer means section for transferring the developed image onto a transfer material, and 16 an unnecessary part on the photoreceptor. This figure shows an IJ-ning means for cleaning the developer and erasing unnecessary latent images.

The developing unit 14 is disposed below the photoreceptor 11, and the main components of the developing unit include a liquid tank 18 containing a developer 17, and a liquid tank 18 containing a developer 17.
A developing roller 19 partially immersed in developer 1γ in 8;
A squeezing roller 20 is in pressure contact with the developing roller 19.

As described in FIGS. 1 and 2 above, the developing roller 19 has a central J-ra 21, an elastic foam 22 made of foamed polyurethane provided around the O-ra 21, and the foam 22. It has an endlessly surrounding conductive net 23.

The center roller 21 of the developing roller 19 receives rotational force from a drive source (not shown) and supports the net 23 so that it rotates in the same direction and at the same speed at the contact portion with the photoreceptor 11.

Further, a squeezing roller 20 is in pressure contact with the developing roller 19 in the developer 17, and the developer in the air bubbles 22 is replaced by the action of the roller 200.

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, at least the surface of the squeezing roller 20 is made of a conductive member such as metal.

24 and 25 are roller electrodes, respectively.

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

Further, 28 and 29 are the power supply section 26 and the roller electrodes 24 and 2.
It is a conducting wire connecting 5.

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 net 23 on the surface of the developing roller 19, or the mesh 23 is grounded. Desirable development conditions can be obtained by applying an appropriate potential.

On the other hand, the electrode member acting on the net 23 is not limited to the roller as described above, but may be a plate-shaped member, or the electrode member may be arranged so as to rub directly against the developing roller 19 without using the squeezing roller 20. Good too.

Next, a developing process to which the present invention is applied will be described in more detail with reference to FIG. 6, which schematically shows a partially enlarged cross section of the developing unit 14 shown in FIG.

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 mesh 23, and the permeated developer is transferred to the photoreceptor 11 by rotation of the developing roller 19.
The image is transported to the development position.

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, the foam 22
It is squeezed out from the inside through the net 23 to the outside of the roller 19 (area B in the figure).

As a result, a large amount of highly concentrated developer is always supplied to the vicinity of the photoreceptor 11 (areas A and B in the figure) during development, and as a result, the time required for development can be shortened, and the developing device can be made smaller. It also makes it possible to

Further, during the above-mentioned development, since the developing roller 19 has elasticity, when it comes into contact with the photoconductor 11, it forms a nip that makes surface contact with a width perpendicular to the rotation axis direction, and this nip width is wide. Moreover, it functions 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.

Further, according to the developing method of the present invention, when the developing roller 19 comes into contact with the photoreceptor 11, the developer is sufficiently squeezed out from inside the developing roller for the above-mentioned reason on the contact surface of the developing roller 19. It will be done.

As a result, the latent image on the photoreceptor 11 is developed with sufficient developer, so that a good developed image is 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 photoconductor 11, part of the developer impregnated in the bubbles 22 is squeezed out onto the photoconductor in the opposite direction to the rotation direction (in the figure). , especially area A).

Therefore, immediately after the contact pressure with the photoreceptor 11 is released,
The bubble 22 is revived from the deformed state due to compression, and at this time,
Since the foam 22 is impregnated with a small amount of developer, it recovers an appropriate liquid absorption ability (region C in the figure).

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

That is, the above-mentioned absorption ability, together with the large surface area and surface tension of the developing roller 19, removes unnecessary carrier liquid, which is the main component of the developer, and unnecessary toner particles, which tend to remain on the surface of the photoreceptor 11 immediately after development. , into the roller 19 through the net 23.

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.

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

Note that in FIG. 6, the points at the developing roller 19 and the developing section schematically indicate the amount 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 is impregnated into the bubbles 22 with a low F concentration due to development. Replace and stir the developer.

The various effects of the lower developing frame mentioned above include impregnating the latent image carrier of the photoconductor cap with developer, squeezing out the developer by elastic deformation, and further removing the developer by resuscitation. by using a flexible member that absorbs the agent.

Furthermore, since the flexible member of the present invention does not destroy the latent image in the latent image-bearing potting soil or disturb the developed image, it does not cause deformation on the surface in contact with the carrier; It changes elastically in the vertical direction.

In the above embodiments, a case has been described in which the latent image carrier has rigidity using the photoreceptor as an example, but of course it may 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 mere felt-like or spongy-like elastic body is directly used as the developing roller, the latent image on the carrier and the elastic body come into strong planar contact, making it impossible to supply sufficient developer, and the developed image A phenomenon occurs in which the surface becomes extremely thin.

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

FIG. 7 shows the flexible member of the present invention configured in the shape of an endless belt,
An embodiment applied to a developing unit of a color copying machine will be shown.

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 macenter developer, 33 is a cyan developer, and 34 is a black developer. developer is used.

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

In the figure, 35 is a liquid tank that contains a yellow developer 36, and a belt-shaped flexible drum 3 that is partially immersed in the developer 36.
7 is suspended by two rotating shafts 38 and 39.

The developing belt 37 is similar to the flexible member g explained in FIG. 4 above.

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

It goes without saying that development may be carried out by raising only the developing belt 37 without raising the entire developing device.
3. An effect of configuring the elastic member in a belt shape as described above is that the developing unit can be made smaller, so in an apparatus in which a plurality of developing units are arranged in one place as in this embodiment, Particularly effective.

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

As described above, the RJJ flexible member of the present invention has the function of absorbing and squeezing out developer, and does not deform in the direction of the contact surface at the pressure contact position when pressed against the latent image carrier, and does not deform in the direction of the contact surface in the pressure contact position. This is because the latent image on the carrier can be developed well by the elastic member that is elastically deformed in the direction.

Furthermore, the flexible member of the present invention supplies sufficient developer to the latent image on the carrier, and furthermore, the developer does not wash away the developed image, so it is a good method for reproducing the original image extremely faithfully. Development - 7J Ko Ding Noh.

Furthermore, since the flexible member absorbs unnecessary developer on the carrier when it is separated from the carrier, development can be completed leaving mainly only 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 flexible member of the present invention to the developing unit,
Most of the drawbacks of conventional liquid development technology could be eliminated.

In addition, in the developing device in the above embodiment, each developing device has one
Although a book developing belt is shown as an example, it is not necessary to be limited to this, although one belt can perform a sufficient function.

Furthermore, each developing device may be provided with a mechanism for accommodating developer for replenishment, 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 applying means as shown in the fifth illustrated example.

By the way, the rotation or eye movement of the developing belt may be operated at substantially the same speed and in the same direction upon contact with the latent image carrier, or may be driven by a driving force from a driving source.
Alternatively, it may be due to frictional movement with the carrier.

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

For example, the shape can be freely selected, such as whether a fiber structure or a foam is used for the foam portion, but considering the development speed, characteristics of the developer, characteristics of the latent image carrier, etc.
Do the appropriate combination.

Finally, 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 carries an electrostatic latent image, and it can be formed in the form of a drum or sheet. , can be applied to members such as web-like members.

Next, as a second application example, a case where the flexible member of the present invention is applied to a liquid squeezing roller of a developing unit will be described with reference to FIGS. 8 to 10.

First, FIG. 8 schematically shows a cross section of the developing unit 41. In the figure, reference numeral 42 indicates a drum-shaped photoreceptor that rotates in the direction of the arrow, and a developing plate below the photoreceptor that also acts as an electrode. 43 is located, and developer is guided to the developing tray 43 by a 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, it is necessary to squeeze out the excess carrier liquid before the transfer process.

Some of these squeezing techniques use a corona discharger, a roller that rotates close to the photoreceptor, or a roller that has an absorbing squeezing effect, such as a sponge.

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

Conventional 0) When trying to squeeze out the excess developer on the photoreceptor using a liquid squeezing means using a sponge roller, it seems that the sponge itself can squeeze the liquid well due to its own characteristics, but the following problems arise. However, there are some difficulties in actual practical application.

That is, as already mentioned in the description of the characteristics of the flexible member of the present invention as the developing roller, when a conventional simple elastic member is used to press the latent image against the photoreceptor, the elastic member, which is soft not only inside but also on the surface, At the nip during the pressure contact, the photoreceptor is also deformed in the tangential direction, and at the same time, the contact surface forms a substantially smooth plane.

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

Furthermore, in the case of a general elastic member made only of foam, the air bubbles and spaces on the surface and in the vicinity collapse at the position where the elastic member comes into pressure contact with the photoreceptor, making it impossible to absorb sufficient liquid during resuscitation.

Furthermore, foamed members tend to foam non-uniformly during formation, which causes a problem in that excess carrier liquid on the photoreceptor cannot be squeezed out uniformly during liquid squeezing.

In addition, since the surface of the elastic member is insulating, there is a strong risk that part of the latent image will be transferred when it comes into pressure contact with the photoreceptor.
In that case, problems arise in the subsequent development results.

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

The flexible member of the present invention, which is applied 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 made of a flexible member of the present invention, and its configuration is similar to that shown in FIG. It has elastic foam 48 and a conductive network 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 rotates in synchronization with the liquid squeezing roller 40 by rotation of a rotating shaft 510.

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.

Thus, the latent image on the photoreceptor 42 can be prevented from being transferred to the surface of the liquid squeezing roller 46.

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 a 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 deep drawing reroller 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 section in FIG.

In FIG. 9, 51 on the photoreceptor 42 is a toner particle image electrostatically attached to the latent image, and 58 is 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 420 to point D on the line connecting the rotation axis of the photoreceptor 420 and the rotation axis of the liquid squeezing roller 47 .

During this time, only a small portion of the net-like body 49 is touching the image formed by the toner particles on the photoreceptor 42 in a static state, so there is no need to worry about rubbing the toner particle image, thereby disturbing the image. There is no.

Also, the elastic foam 48 extends from the population side E to the above-mentioned point.
rotates while elastically contracting and deforming the bubble, during which time some of the liquid 58 of the photoreceptor 42 seeps into the bubble 48 through the net 49, and some of it is on the person's side. It accumulates in E.

In other words, the surface of the deep drawing roller 46 is in pressure contact (~
Even if the surface is deformed 1-, the passage opening will not be crushed even if the carrier liquid is transferred from point D to point F.
Transfer by shooting one shot (~obtain).

As a result, the deep drawing roller 46 that has passed through point D is deformed in the direction of resuscitation deformation. The carrier liquid is forcibly absorbed into the bubbles 48 immediately after passing through.

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

After the deep drawing roller 46 is separated from the photoreceptor 42, it is then brought into pressure contact with a rotating roller 50 for squeezing out the developer.

The rotating roller 50, which presses and rotates in the same direction as the L-marked deep-drawing roller 46 at the press-contact position, transfers the carrier liquid absorbed from the surface of the photoreceptor 420 to the population side G between the deep-drawing rollers 46, such as [1-L50]. The included developer 58 accumulates as shown in the figure.

As the amount of accumulated developer 58 increases, it exceeds the M roller 50,
Furthermore, the cleaning blade 54 of the reader/ra 50FfJ
The liquid falls through the upper side of the tank (not shown) into the tank.

Then, the deep drawing roller 46 exits with the developer squeezed out by the rotary roller 50.

In the above embodiment, the rotating direction of the rotary roller 50 and the rotating shaft of the deep drawing roller 46 is set to be opposite to that of the deep drawing roller 46, but depending on the surface condition of the deep drawing roller 46 and the degree of pulling force can also rotate in the same direction.

FIG. 10 shows an embodiment in which a rotating roller for squeezing out the developer is provided close to the population side E.

In the figure, 59 is a rotating shaft, 60 is its rotation axis, 61 is a blade for cleaning the roller 59, and 62 is a rotating shaft.
is a guide means consisting of a plate member for guiding the developer accumulated on the artificial side (1) of the two rollers into a liquid tank (not shown).

Both the examples shown in FIGS. 9 and 10 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.

In the example device, a photoreceptor was used as an example, but of course, σ
It is also applicable to liquid development of latent images formed on other insulators 1-1-4.

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

By the way, the deep drawing roller described above can also be used as a liquid flow IE means that has the function of preventing the developer or cleaning liquid flowing from the upper part of the drum-shaped photoreceptor from flowing below the predetermined position.

Next, as a third application example, when the flexible member of the present invention is applied to a cleaning means part or a cleaning roller.
The first embodiment will be explained with reference to FIGS. 11 and 12,
Further, a second embodiment will be explained with reference to FIGS. 13 and 14.

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

In FIG. 11, reference numeral 63 denotes a drum-shaped photoreceptor that rotates about a central axis 64 in the direction of the arrow.

A cleaning port 65 arranged above the photoreceptor 63 is made of a flexible member of the present invention, and mainly removes toner particles remaining on the photoreceptor 63-E after transfer.

The photoreceptor cleaned by the cleaning roller 65 is
Rotate further in the direction of the arrow for the next image forming process.

By the way, the configuration of the cleaning roller 65 is shown in FIGS. 1 to 3, and any structure may be used, but in this embodiment, the first
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 conductive network.

Cleaning: The cola 65 and the photoreceptor 63 move in opposite directions on their pressure contact surfaces, and the rubbing caused by the movement scrapes off l- particles and the like on the photoreceptor 63 for cleaning.

In the figure, 69 and 70 are conduits that collect the developer in the developer tank (not shown) pumped up by the pump 71 to the cleaning roller 65.
supply to

When the above-mentioned developer supply has been stopped for a long period of time, toner particles may be removed from the cleaning roller 65.
This is especially necessary since the surface of the photoreceptor is easily damaged by solidification L between the L and the photoreceptor 63 and rubbing.

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 sent to the cleaning roller 65 for cleaning.
supply to

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

The n1 flexible member according to the present invention provides various effects that cannot be seen in the application of a conventional simple sponge roller.

That is, since the conductive network body 68 is present on the surface of the cleaning roller 65 in this embodiment, a voltage is applied through the conductive network body 68, thereby adding the effect of electrically suctioning and collecting the toner.

For example, when 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 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. An electric field is generated in the direction of pulling away from the

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 activated, as shown in the figure, the developer 72 accumulates on the photoreceptor 63 that first comes into contact with the cleaning roller 65, and begins to flow downward as the photoreceptor 630 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 stopper member 73 and the photoreceptor 63 reaches the groove 74 at the end of the photoreceptor 63 due to the slope formed by the member 73, and returns to the liquid tank (not shown).

In FIG. 11, 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 a rotating shaft of the photoreceptor 630, 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.

Compared to the conventional case of using a simple sponge roller, the effects obtained by using the flexible member of the present invention include, as mentioned above, sufficient wetting can be achieved on the pressure contact surface even during pressure contact sliding, In addition, the toner particles can be removed more easily due to the effect of the electric field.

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

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

Next, another embodiment shown in FIG. 13 will be described.

In this embodiment, the rotational relationship between the cleaning roller 65 and the photoreceptor 63 is reversed from that shown in FIG. 11 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 peripheral speed of the roller 65 is higher or lower than the peripheral speed of the photoreceptor 63, and the photoreceptor 63 and roller 65 slide against each other due to their relative speeds. Configure to suit.

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 eleventh figure.
An appropriate amount of developer is pumped up from a liquid tank (not shown) by a pump 71 and supplied to the cleaning roller 65 through conduits 78 and 79.

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, and the developer oozes out to wet the toner particles on the photoreceptor to be cleaned.

Thereafter, for the same reason as in the case of the eleventh 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 at that time, reaches the position of the conduit 78 again, and squeezes out the absorbed toner particles together with the developer. do.

When the cleaning roller 65 is installed on the photoreceptor 63, it is better to install it obliquely to the rotation axis of the photoreceptor 630, as shown in FIG. 14, that is, the nip position forms an inclination on the photoreceptor surface.

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. 11, there is no need to provide a liquid flow stopper for preventing the developer from flowing down to the latent image forming position, and the structure is simple.

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

Further, if the conduit 78 can supply sufficient liquid to the roller 65, the number of conduits 79 is not necessarily required.

Furthermore, in this embodiment, the cleaning roller 65 is installed at an inclined position from the uppermost position of the photoreceptor 63 to the latent image forming position, and in particular, a position where the developer accumulated on the conduit γ8 side does not flow out to the transfer side. choose.

In addition, in E-E, only the case where the flexible member illustrated in FIG. 1 is used is described, but other flexible means of the present invention 1 can be widely applied.

Further, the illustrated embodiment may be modified so that a voltage suitable for erasing the latent image 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 a photoreceptor but also an insulating member for transferring another latent image as in each of the above embodiments, and the shape is not limited to a drum-like one.

As described above, the flexible member according to the present invention can be widely applied as a developing means, a liquid squeezing means, a liquid flow stopping means, and a cleaning means in an image forming apparatus using a liquid.

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

[Brief explanation of the drawing]

1 and 2 are perspective views showing a partial cross section of an embodiment of a flexible member according to the present invention, and FIGS. 3 and 4 are sectional views of an embodiment of a flexible member according to the present invention. , FIG. 5 is a sectional view of a copying machine schematically showing an example of application of the present invention to a developing unit in a copying machine, and FIG. 6 is a partial sectional view of the developing unit showing an enlarged view of the developing process shown in FIG. 5. FIG. 7 shows a partial sectional view of a copying machine according to another application example of the present invention. Also, FIG. 8 is an enlarged sectional view of the developing device for explaining the liquid squeezing part, FIGS. 9 and 10 are partially enlarged sectional views of the embodiment of the iris [1-L], and FIGS. 11 and 13. 12 is an explanatory diagram showing a method of installing the liquid flow stopper member shown in FIG. 11 on the photoreceptor, and FIG. is the first
FIG. 4 is an explanatory diagram showing a method of installing the cleaning roller shown in FIG. 3 on the photoreceptor. In the figure, 1, 6...-1j1 flexible member, 2.
...Center roller, 3, 9, 22, 48, 67...
...Elastic foam, 3A...Inner layer, 3B.
...Outer layer, 4゜10.19, 23, 49, 68
... Conductive network, 5 ... Porous surface layer, 7, 8 ... Rotating shaft, 11°4263 ...
...Photoreceptor, 14, 41...Developer section, 18
35.55...Liquid tank, 19...Developing roller, 17.36,56,58,72...Developing agent, 20°5059... Squeezing roller, 21...
... Center roller, 2425 ... Roller electrode, 26 ... Power supply section, 27 ... Voltage source,
28, 29, 53... conductor, 38.39,
47,51.60,66...rotation axis, 46...
...Liquid squeezing roller, 65...Cleaning roller, 54, 61...Blade, 62...
...Guiding means, 44,71...Pump, 69
,70,78゜19... conduit, 73...
・Liquid flow stopper member.

Claims (1)

[Claims] 1 An elastic foam that has a porous layer that allows liquid to pass through, squeezes out liquid when compressed, and absorbs liquid when restored from the compressed state, and has an insulating layer on its peripheral surface. A flexible member for an image forming apparatus, comprising a net or an insulating porous film, the surface of the net or porous film being coated with a conductive substance.