JPH10268651A - Liquid absorbing roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liq. absorbing roll having stable liq. absorbing property and strength, capable of selectively regulating the concn. of toner particles in a liq. developer and capable of easily restoring function in a short time when the function is deteriorated by wear and contamination by the liq. developer. SOLUTION: A layer having elasticity and electric conductivity and a liq. absorbing layer are successively laminated on a roll shaft in the form of nearly concentric circles to obtain the objective liq. absorbing roll. The liq. absorbing layer is made of nonwoven fabric and at least the top layer is three- dimensionally intertwisted nonwoven fabric. The layer having elasticity and electric conductivity is formed by laminating a metallic layer on an elastic layer. Each of the layer having elasticity and electric conductivity and the roll shaft has a structure permeable to a component of a liq. developer and the roll shaft has a hollow structure from the part coated with the layer having elasticity and electric conductivity to at least one end. The nonwoven fabric of the liq. absorbing layer has a structure ensuring no difference in level for the peripheral surface of the roll.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid absorbing roll for supplying a liquid developer to an image bearing member on which an electrostatic latent image is formed, developing the image bearing member, and removing excess liquid developer on the image bearing member. ,
More specifically, the present invention relates to a liquid-absorbing roll capable of selectively adsorbing a component having an attractive or repulsive force in a liquid developer component or allowing the component to remain on an image carrier.

[0002]

2. Description of the Related Art A liquid-absorbing roll is used for removing a liquid material remaining on a surface or a hole of a liquid-absorbing substrate by pressing and slidingly contacting the liquid-absorbing substrate on which the liquid material to be absorbed is attached. Can be The liquid absorbing roll is generally composed of a liquid absorbing material having at least the uppermost layer of the roll with a large number of pores,
As the liquid absorbing material, a woven fabric, a nonwoven fabric, a laminate thereof, and the like have been used in addition to a natural sponge or a synthetic resin foam.

[0003] Although these liquid-absorbing materials have excellent liquid-absorbing properties, the liquid-absorbing action mainly utilizes a physical action such as a so-called capillary phenomenon, so that all components of the liquid material are non-selective. Even if a specific component is absorbed selectively or only a specific component is selectively absorbed, the chemical affinity between the liquid-absorbing component and the liquid-absorbing material is further utilized, as long as the liquid is absorbed except for particulate matter larger than the pores. Or a liquid containing a component having an electrically attractive or repulsive force,
It is possible to selectively absorb a specific component while applying an electric action, even if the liquid absorbing means is a sheet or the like, and the liquid absorbing material is disposable after the liquid absorption without regenerating as a disposable material.
At least in the form of a liquid absorbing roll, it is difficult to replace or regenerate the liquid absorbing material after absorbing the liquid, and there is substantially no advantage of using a roll for disposable use.

In addition, a liquid containing a component having an electrically attractive or repulsive force is obtained by dispersing electrically-charged heat-film-forming colored fine particles (toner particles) in a dispersion medium (carrier liquid) composed of an insulating organic solvent. In the case of a liquid developer, if a conventional liquid absorbing roll is used to remove excess liquid developer after development in a liquid developing process, toner particles absorbed together with the carrier liquid will be generated as the liquid absorbing roll dries. Even after the carrier liquid evaporates, the carrier liquid remains inside the roll fine pores and closes the fine pores to lower the liquid absorbing function, which not only causes uneven absorption (removal unevenness) and retransfer of the residual toner particles, but also causes this absorption. In some cases, the liquid absorption support means and the liquid absorption roll that are in contact with the liquid roll so as to be urged adhere to each other with toner particles and become unable to rotate.

Japanese Unexamined Patent Publication (Kokai) No. 55-153971 discloses that a conductive suction roll having open pores is brought into contact with the surface of a photoconductive layer, and a potential having the same polarity as that of toner particles in a liquid developer is applied to the roll. And a method for removing the liquid developer in which the relative movement of the toner particles between the surface of the photoconductive layer containing the electrostatic image and the photoconductive layer is substantially zero. In a developing device to which this method is applied, an adjusting roll for controlling the amount of the liquid developer supplied before reaching the suction roll is arranged, and the suction roll is used to scrape the sucked carrier liquid. The wiping pieces to be taken are in contact.

According to this method, at least the remaining of the toner particles in the pores and the accompanying toner fixation are improved.
If the absorption of the carrier liquid in the roll is saturated, the squeeze roll to which a voltage can be applied becomes a squeeze roll, and the original function and effect cannot be exhibited. Cannot be made compact. Further, the wiping part cannot completely remove the absorbed carrier liquid.

Further, Japanese Patent Application Laid-Open No. 3-80274 discloses that
A sponge roll that removes excess liquid developer has a hollow structure that can suck the liquid developer from the inside,
Excess developer removing device having suction means for applying a negative pressure to the roll hollow portion to suck the liquid developer penetrating into the sponge, and a roll cover for covering a roll portion not used for sucking the liquid developer Is disclosed. In the roll in this apparatus, the absorbed liquid developer is forcibly removed through the hollow portion of the roll, so that the liquid does not basically reach saturation.

However, although the toner particles of the electrostatic latent image portion forming the image portion are electrostatically attached, some of the upper layer is peeled off by forcible suction, and the image density is reduced. In addition to inviting, there is no means to actively suppress toner particles into the sponge, including electrical methods,
The toner particles are sucked together with the carrier liquid, and as a result, the toner particles are likely to remain inside the sponge pores of the roll, and the absorption of liquid and the sticking over time are easily induced. Furthermore, in the production of a roll, liquid absorption (liquid permeation), elasticity as a roll,
In addition, it is necessary to control not only the thickness of the sponge but also the pore diameter and the like in consideration of the uniformity of the liquid absorption, which is complicated.

Further, Japanese Unexamined Patent Publication No. 7-225516 discloses an apparatus for removing excess developer, which combines the above techniques. That is, a porous liquid absorbing roll for sucking excess developer on the image carrier is provided, and the porous liquid absorbing roll is provided on a porous sleeve that is permeable, conductive and rigid, and on the porous sleeve. An excess developer removing device comprising a coated conductive and elastic porous layer, preferably a foam made of conductive polyurethane manufactured by a wet method, and provided with vacuum piping.

This porous material absorbing roll is disclosed in JP-A-55-1.
As described in JP-A-53971, a bias voltage having the same polarity as that of the toner particles is applied to the porous sleeve, and
By vacuuming from a vacuum pipe as described in Japanese Patent No. 0274, the toner particles are selectively absorbed by the carrier liquid component in the excess liquid developer on the image carrier while remaining at the interface between the roll and the image carrier. It is possible to liquid. Further, since the roll member is composed of a rigid part and an elastic part, it can be reliably and stably contacted with the image carrier.

[0011] However, the porous liquid absorbing roll has
In order to make the vacuum for removing the liquid developer remaining on the image carrier effective, at least to improve the liquid absorption of the conductive and elastic porous layer, the fineness is the same as in the case of the sponge. The pore diameter must be increased and the wall thickness must be reduced, but if the pore diameter is increased, the uniformity of liquid absorption is impaired.If the wall thickness is reduced, elasticity is not effectively exhibited and step-like unevenness of drawing is induced. Is more likely to do so.

A bias voltage is applied to this roll,
Even if the toner particles in the liquid developer are prevented from entering the pores, the liquid developer is vacuumed, so that the use period is prolonged. It may remain, and may cause liquid absorption inhibition or sticking over time. If the absorption of liquid by toner particles occurs, the porous sleeve part can be regenerated by dissolving and washing the toner particles with a solvent, but at least the surface of a conventional roll that does not substantially have liquid absorbing properties. It is extremely difficult to wash the porous layer to the extent that it is washed, and at least the porous layer must be rewound in order to completely restore its function.

Furthermore, since a conductive and elastic porous body to which a bias voltage is applied on the outermost periphery of the roll comes into contact with the electrostatic latent image to be developed, if the development by the normal development method is performed, Problems such as sparse electrodeposition of charged toner particles on the non-image portion of the electro-latent image, or the deposition of trace impurities in the solvent component of the liquid developer resulting in image disturbance Is easy to occur.

On the other hand, in the reversal developing method, a conductive and elastic porous body to which a bias voltage is applied on the outermost periphery of the roll comes into contact with the electrostatic latent image after or during development. Due to the unevenness of the surface, some parts may not be in direct contact with the photoconductive layer, which is the object to be developed, and some parts may not be applied. The development state is affected. Actually, when developing a line having a width of approximately 10 μm or less formed by an electrostatic latent image, it is an absolute condition that irregularities on the surface of a porous body having conductivity and elasticity are extremely small,
When connecting the pressure reducing means to the innermost part of the roll structure and trying to suck the liquid component, an unrealistic vacuum pressure is required, and most of the solvent component evaporates due to the reduced pressure,
It is difficult to recover the solvent component.

[0015]

SUMMARY OF THE INVENTION The present invention has a stable liquid absorbing property, a liquid retaining property, and a strength. By applying a necessary voltage to the conductive layer, the toner particles contained in the liquid developer can be removed. To provide a suction roll capable of selectively adjusting the concentration, and further capable of recovering the function easily and in a short time when the function is deteriorated due to wear due to use over time or contamination by liquid. It is in.

[0016]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems. As a result, after supplying a liquid developer to an image carrier on which an electrostatic latent image has been formed and developing it, an image is formed. A liquid absorbing roll for removing excess liquid developer on a carrier, wherein the liquid absorbing roll is formed by laminating a layer having elasticity and conductivity substantially concentrically with a roll axis and a liquid absorbing layer in this order. It has been found that a liquid-absorbing roll characterized in that the liquid-absorbing layer is made of a non-woven fabric and at least the uppermost layer is a non-woven fabric subjected to a three-dimensional entanglement treatment.

The nonwoven fabric according to the present invention will be described in detail later. In general, the nonwoven fabric is entangled without knitting the fibers, and the strength is increased by a chemical method using an adhesive or bonding by a machine (pressure or heat). In the improved web, not only can the density of the fiber matrix and its pore size be easily adjusted mainly by the fiber diameter or the bonding method, etc. Flexibility (elasticity) can be maintained. Further, by performing three-dimensional confounding treatment on the web, it is possible to improve the fuzziness of the fibers on the surface and improve the strength of the web, and it is particularly effective to secure pores in the thickness direction when the thickness is increased.

Therefore, by forming at least the uppermost layer of the liquid-absorbing layer of the liquid-absorbing roll with a three-dimensionally entangled nonwoven fabric, at least the layer made of the nonwoven fabric can be sufficiently elastic as the liquid-absorbing layer as a whole. Even if it is provided, sufficient liquid absorbability can be secured. In addition, the surface property and liquid absorption of the roll can be freely adjusted by changing the fiber diameter and the degree of entanglement of the nonwoven fabric to be laminated, and laminating two or more nonwoven fabrics having different densities (pore diameters). It is possible. When two or more nonwoven fabrics are used, the nonwoven fabric other than the uppermost layer of the liquid absorbing layer does not necessarily need to be a three-dimensional entangled nonwoven fabric. Furthermore, since the lamination of the liquid absorbing layer basically only requires winding the nonwoven fabric to a required thickness, lamination is easier than sponge or polyurethane rubber.

In the above liquid absorbing roll, the elastic and conductive layers are formed by laminating a metal layer on the elastic layer, so that the elastic layer provided around the roll axis can be provided.
A metal layer having conductivity provided on the outer periphery thereof, and a liquid absorbing layer provided on the outermost periphery respectively provide adhesion between the image carrier and the liquid absorbing roll, generation of an electric field on toner particles contained in the liquid developer, Since the respective properties of the liquid absorbing property and the abrasion resistance are shared, each design is limited according to the purpose, so that a high-performance liquid absorbing roll can be provided.

The layer having elasticity and conductivity and the roll shaft have a structure through which the liquid developer component can pass, and the portion of the roll shaft provided with the layer having elasticity and conductivity from at least one shaft end. By having a hollow structure, if vacuum means is connected to this roll shaft, the liquid developer is discharged out of the roll via the liquid absorbing layer, the layer having elasticity and conductivity, and the roll shaft, and continuously. A large amount of liquid can be absorbed. Further, by applying a necessary voltage to the conductive layer, a continuous liquid absorbing step of the liquid while selectively concentrating or removing the charge holding component contained in the liquid becomes possible. The layer having the property can prevent the liquid developer from remaining.

Further, by applying a necessary voltage to at least the conductive portion of the layer having elasticity and conductivity at the time of vacuum, the toner particles in the liquid developer are not positively taken into the roll. And at least electrodeposition on a layer having conductivity. In any case, the carrier liquid in the liquid developer can be removed from the image carrier.

Further, by forming the nonwoven fabric in the liquid absorbing layer to have a structure in which there is no step on the outer peripheral surface of the roll, the unevenness of the developing step which depends on the outer peripheral length of the roll is prevented.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the liquid absorbing roll of the present invention will be described below in detail. The liquid absorbing roll of the present invention is a roll used to remove excess liquid developer on the image carrier after supplying and developing a liquid developer on the image carrier on which the electrostatic latent image is formed. A liquid absorbing roll in which a layer having elasticity and conductivity and a liquid absorbing layer are concentrically laminated on the roll axis in this order, the liquid absorbing layer is made of a nonwoven fabric, and at least the liquid absorbing layer The uppermost layer is a liquid absorbing roll made of a nonwoven fabric subjected to a three-dimensional entanglement treatment.

The fibers used in the nonwoven fabric according to the present invention include fibers of polyvinyl chloride, polyvinylidene chloride, polyolefin, polyacrylonitrile, polyamide, polyester and polyvinyl alcohol. In the present invention, since it is used for removing excess liquid developer, it is desirable that the developer be at least inert to the carrier liquid. These fibers may be mixed and used as needed. In particular, in the case of the nonwoven fabric of the three-dimensional entanglement treatment according to the present invention, a binder fiber that can be dissolved and removed in the entanglement treatment step, for example, a polyvinyl alcohol-based fiber that dissolves and flows out with a water stream is mixed to strengthen the nonwoven fabric base material. Is preferred.

The cross-sectional shape of the fibers constituting the nonwoven fabric according to the present invention is not particularly limited, and fibers having a so-called irregular cross-sectional shape such as an elliptical shape, a triangular shape, a star shape, a T-shape, a Y-shape, and a leaf shape may be used. . Rather, since the porosity and specific surface area of the nonwoven fabric are improved, it is preferable to use fibers having a cross-sectional shape other than circular. Further, fibers having voids (voids) on the surface or fibers having a branched structure may be used.

Fibers having a core-in-sheath structure are also preferably used in that the bonding strength between fibers and the stiffness when forming the nonwoven fabric can be appropriately controlled. Examples of the fiber having a core-sheath structure include a fiber whose core portion is made of polyester and a sheath portion made of a polyester copolymer, and a fiber whose core portion is made of polyester and whose sheath portion is made of polyolefin. The feature of the core-sheath structure is that the softening point is different between the core part and the sheath part, but since the core part needs to maintain the shape of the fiber during heat treatment during processing,
It is preferable that the sheath portion has a softening point of about 230 ° C. or more, while the sheath portion has a softening point of about 90 ° C. to 120 ° C. because the fibers themselves need to be thermally bonded to each other to form a sufficient bond. When fibers having a core-sheath structure are used, strength can be maintained without high-temperature heat treatment.

The components constituting the nonwoven fabric according to the present invention include, in addition to the above-mentioned materials, natural fibers such as wood pulp, hemp pulp, espart, and cotton fibers, and regenerated and semi-synthetic fibers such as rayon fibers and acetate fibers. And inorganic fibers such as metal fibers, ceramic fibers, rock wool fibers, glass fibers, alumina fibers, zirconia fibers, silicon nitride fibers, silicon carbide fibers, and carbon fibers. These fibers are preferably used together within a range that does not deteriorate the properties such as the strength and the air permeability of the nonwoven fabric composed of only the above fiber group.

Fibers in which a flame retardant is chemically incorporated into or physically mixed with the above fibers, or nonwoven fabrics composed of general-purpose fibers may be treated with a flame retardant. Of these,
In terms of processability and material price, known flame retardants such as phosphorus, halogen, and inorganic are chemically incorporated into general-purpose fibers such as polyester, polyolefin, acrylic, and rayon. Physically compounded fibers are preferred.

The nonwoven fabric according to the present invention includes a wet method in which the above fibers are suspended in water and formed into a sheet by a wet papermaking machine, a resin bond by resin bonding, a needle punch using entanglement with a needle, a stitch bond knitted by a yarn, Alternatively, a so-called dry method called thermal bond bonded by heat, jet bond in which high-pressure water is sprayed from a nozzle and entangled, spun bond which is formed into a sheet while directly spinning, fibrillated using the spraying principle when directly spinning It is manufactured by a melt blown or the like that forms a sheet while making microfibers. By appropriately selecting these production methods, the thickness of the obtained nonwoven fabric, the porosity, the shape of the voids, as well as physical properties mainly related to liquid absorption such as pore size, flexibility, elasticity, and Characteristics mainly related to texture such as fluffing can also be changed. Among these manufacturing methods, in order to obtain an appropriate strength, a spun bond or a jet bond is preferable.

The nonwoven fabric used for at least the uppermost layer of the liquid absorbing layer according to the present invention is subjected to a three-dimensional entanglement treatment in order to impart a suitable mechanical strength. The entanglement treatment is a method in which a single layer or a plurality of layers of a nonwoven fabric are placed on a support, and a mechanical treatment is performed on the nonwoven fabric to three-dimensionally entangle the fibers. Specific examples include a needle punching method and a hydroentanglement method, and the hydroentanglement method is preferable because the entangling is performed uniformly and the production speed is high. More specifically, the water entanglement method is a method in which a water stream is jetted from above the nonwoven fabric to three-dimensionally entangle the fibers constituting the nonwoven fabric to develop strength.

When the entanglement treatment is not performed, the fibers are arranged in layers vertically in the cross section of the nonwoven fabric, and if no binder is added, the fibers become separated after drying, and no tensile strength can be obtained. Further, the voids have a shape intersecting at a straight angle at an acute angle, and the porosity cannot be increased. On the other hand, when the entanglement treatment is performed, the upper and lower fibers are entangled with each other, and the strength is exhibited without adding a binder. Moreover, as a result of the fibers being bent and entangled up and down, the voids also expand up and down, resulting in an elastic nonwoven fabric rich in voids. Further, the shape of the void becomes significantly rounder than before the confounding.

In the present invention, it is preferable to use a nonwoven fabric in which the fibers are not bound or the binder is dissolved and removed at the stage of the three-dimensional entanglement treatment even if the fibers are bound before the entanglement. Is preferably a wet method. The wet method is preferable because it has high productivity and can produce a homogeneous web. If necessary, the above-mentioned forming methods may be combined, and the obtained webs may be laminated and entangled. Furthermore, as long as the performance of the nonwoven fabric of the present invention is not impaired, a web obtained by a method other than the above may be laminated.

As a condition for performing three-dimensional confounding firmly and properly, the diameter of a nozzle for jetting a water flow is 10
~ 500 µm is preferred. Nozzle spacing is 10-150
0 μm is preferred. The shape of the nozzle is preferably circular, and a nozzle capable of jetting a so-called columnar water flow is preferable. The support on which the nonwoven fabric is loaded is preferably a porous support of about 50 to 200 mesh. These nozzles need a range that covers the width of the sheet to be processed in the direction perpendicular to the papermaking direction, and for the papermaking direction, the type of nonwoven fabric, the basis weight,
In consideration of the processing speed and the water pressure, the number of nozzle heads can be changed and used within a range where sufficient confounding can be obtained. The processing speed is preferably in the range of 5 to 200 m / min. Water pressure is 1
The range is preferably 0 to 250 kg / cm ² , and more preferably 50 to 250 kg / cm ^2.
250 kg / cm ² is preferred.

In addition to these conditions, the water pressure is gradually increased from the initial stage to the end stage of processing, the nozzle diameter and the nozzle interval are sequentially reduced, the nozzle head is rotated, the support is vibrated left and right, The surface quality can be improved by inserting a wire between the web and the web to sprinkle the water flow, or by using a fan-shaped water flow. The three-dimensional confounding method can be applied not only to one side but also to both sides. After the confounding, nonwoven fabric may be further laminated and confounding may be performed.

The fiber length of the fibers in the nonwoven fabric according to the present invention is preferably 1 to 50 mm. Particularly, in a nonwoven fabric subjected to a three-dimensional entanglement treatment, a nonwoven fabric having a fiber length of more than 50 mm is not preferable because the fiber is entangled during dispersion of the fiber. Furthermore, if the fiber is too short, it will fall off at the time of confounding, and the confounding will be insufficient, and the strength will decrease. Therefore, in consideration of the strength and uniformity after confounding, the range of 5 to 30 mm is preferable.

The fiber diameter of the nonwoven fabric is preferably from 1 to 50 μm, more preferably from 4 to 30 μm. In general, the fiber diameter is 1 μm, depending on the manufacturing method of the nonwoven fabric and the conditions of the confounding treatment.
If it is less than 1, the nonwoven fabric becomes dense, and thus the pore size becomes small and the amount of liquid absorption becomes poor, and the toner particles are liable to remain in the nonwoven fabric matrix, which is not preferable. Conversely, if it exceeds 50 μm, the stiffness of the fiber becomes high and the entanglement treatment becomes insufficient. Further, although the pore diameter and the liquid absorption amount are increased, the liquid absorption unevenness and the image unevenness on the image carrier are easily induced, which is not preferable.

The basis weight of the nonwoven fabric is 20 to 100 g /
m ² is preferable, and 40 to 90 g / m ² is more preferable. If the basis weight is less than 20 g / m ² , the web strength becomes insufficient, which causes breakage during processing or use. Depending on the method of laminating the nonwoven fabric in the liquid absorbing roll of the present invention,
At least the top layer of the liquid absorbing roll of the present invention has a basis weight of 10
If a nonwoven fabric exceeding 0 g / m ² is used, when the end of the nonwoven fabric comes to the periphery, unevenness in liquid absorption or image unevenness on the image carrier is likely to be induced at that portion, which is not preferable. On the other hand, the thickness of the nonwoven fabric may be appropriately selected from the basis weight and the liquid permeability determined by the fiber used, the confounding treatment conditions, and the like, and is not particularly limited.

The liquid absorbing roll of the present invention is formed by laminating a non-woven fabric on a layer having elasticity and conductivity. The nonwoven fabric is cut while sequentially lengthening the nonwoven fabric in accordance with the outer circumference of the outermost layer including the layer having the layer, and the two ends of the nonwoven fabric are wound at the same position, or shifted so as not to overlap, or a method such as these. Lamination is performed by a combination method. In particular, when winding pre-cut pieces,
The length of the two parallel sides is the length of the outer circumference of the suction roll, and the distance between the two sides is cut into a parallelogram that is the width of the suction roll. Preferred.

A preferred configuration of the lamination is that the lower layer of the liquid absorbing layer according to the present invention is made of a nonwoven fabric having a lower density or a larger fiber diameter (that is, a larger interfiber pore diameter), and the uppermost layer is formed of a fiber diameter. The winding is performed using a nonwoven fabric that has been subjected to a three-dimensional entanglement process that is thin and has a low basis weight (that is, the effect of the end of the nonwoven fabric is less likely to occur). As described above, the arbitrary cross section in the roll diameter direction of the laminated nonwoven fabric is always the same layer configuration, and the density and the like of the nonwoven fabric may be concentrically different from the roll axis. If the layer structure is different, the liquid absorption may not be uniform in the circumferential direction of the roll, so it is important to use a nonwoven fabric having uniform characteristics at least concentrically.

Further, even if the layer structure is uniform, if there is a step in the uppermost layer of the roll, uniform liquid absorption cannot be achieved.
In the sense of enabling continuous contact with the developing object and preventing the occurrence of liquid absorption unevenness generated by stepping in the driving direction, the form of the nonwoven fabric according to the present invention on the liquid absorbing roll is as follows. It is preferable to have a structure having no step at least on the outer peripheral surface of the liquid absorbing roll.

As a method of forming a structure having no step on the outer peripheral surface of the liquid absorbing roll on the outermost peripheral surface of the liquid absorbing roll, a nonwoven fabric is cut into a string shape, and one of the nonwoven fabrics is cut at one end of the roll shaft or one end of an elastic and conductive layer. There is a method in which the end is fixed to the other end of the roll shaft or the other end of the conductive layer by helically winding it without any gap and overlapping with the lamination surface, and fixing the end. The wound non-woven fabric may be partially adhered to the layer having elasticity and conductivity for the purpose of preventing the non-woven fabric from falling off. When a string-shaped nonwoven fabric is used, its width is desirably 10 to 100 times the thickness of the nonwoven fabric, and is easy to process.
When considering deterioration due to use over time, 15 to 30
Double is preferred.

Other methods for forming a structure having no step on the outer peripheral surface of the liquid absorbing roll on the outermost peripheral surface of the liquid absorbing roll include a method of fuzzing the end portion of the nonwoven fabric and entanglement with a nonwoven portion which overlaps at the time of winding. In the use of a method of joining the ends by bonding with an adhesive or heat-sealing by hot pressing or the like and smoothing the joints so that the ends do not peel off even when sliding on the image carrier, and Examples of the method include joining the suturing or the like, or covering the entire outer periphery vertically and horizontally with a thread or a net. These joining methods may be used in combination of two or more kinds of joining methods, and may be performed by stitching a heat-sealed portion or an adhesive portion, or by heat-sealing a portion stitched with a plastic resin fiber to form the same. The parts may be joined by two or more methods.

Further, the bonding may be performed using a thermoplastic resin having a heat bonding property. The use of a thermoplastic resin is effective because not only can the nonwoven fabric itself be firmly bonded at the end while suppressing thermal deformation of the nonwoven fabric itself, but also because it is hardly affected by the liquid developer. As the thermoplastic resin used in the present invention, ethylene vinyl acetate copolymer or a modified product thereof, ethylene acrylate copolymer, ionomer, polyamide, nylon, polyester, polyethylene, polypropylene, vinyl acetate copolymer, cellulose triacetate, etc. And cellulose-based resins, polymethacrylate-based resins, polyvinyl ether-based, polyurethane-based, and polycarbonate-based resins.

On the other hand, the end of the non-woven fabric that comes into contact with the elastic and conductive layer forms a product simply by winding the non-woven fabric without any particular treatment, but the liquid absorbing layer may run idle. It is fixed to the outermost peripheral surface of the lower layer which comes into contact with the nonwoven fabric constituting the liquid absorbing layer such as the layer having elasticity and conductivity by using an adhesive, a metal or resin tack, a nail, a wire, a wire, a string, or the like. It is desirable.

The nonwoven fabric according to the present invention may be provided with conductivity, so that the liquid absorbing layer also has conductivity. In the present invention, the conductivity may be imparted to the fiber prior to the production of the nonwoven fabric, or may be imparted to the fiber after production of the nonwoven fabric by using a web or a sheet. Examples of methods for imparting conductivity include a method of attaching a conductive resin such as polypyrrole and polypyridine to fibers, a method of attaching conductive carbon together with a binder resin, and a method of plating metal by electroless plating. There is a method using a conductive fiber having conductivity itself. Since the fibers are subjected to the three-dimensional entanglement treatment, the fibers after the electroconductivity treatment have flexibility, and fibers that do not decrease the conductivity during the entanglement treatment are preferable.

In general, a method of forming a metal film on the surface of a fiber or a nonwoven fabric includes a method by vapor deposition, a method by electroplating, and a method by electroless plating. This is a preferable method for uniformly forming a metal layer on the surface in that a thin conductive metal film can be formed on the substrate and the adhesion is good. The electroless plating process is basically a two-step process of providing a catalyst and an electroless plating process. Usually, a conditioning process for cleaning and degreasing the surface of the support surface with sodium hydroxide or the like, A microetching process using sulfuric acid or chromic acid, etc., which roughens the surface to obtain an anchor effect on the layer, a pre-dip process for preventing deterioration of the catalyst solution, sulfuric acid for activating the catalyst,
An activation step with an acid or alkali such as sodium hydroxide or the like is added before or after the activation step. If necessary between each process,
Steps such as rinsing, draining, and drying are added to stabilize the processing solution and improve the adhesion and uniformity of the plating film.

As a method for producing a conductive fiber by electroless plating on the organic fiber, after the fiber is spun, plating is performed by continuously passing through the above steps without cutting.
After plating, a method of manufacturing by cutting into a fiber length suitable for nonwoven fabric preparation, or after adjusting the fiber length in advance, immersing this fiber in the treatment solution of the above step, filtering the treated fiber, washing with water, and further And a method of repeating the step of dipping in the treatment liquid.

The thickness (layer thickness) of the liquid-absorbing layer portion of the liquid-absorbing roll of the present invention depends on the density and elasticity in the thickness direction of the laminated non-woven fabric, or the liquid permeability of the liquid-absorbing layer depending on the lamination method. And the elasticity greatly changes, so it cannot be specified unconditionally, but it is preferably about 2 to 20 mm, more preferably 3 to 10 m
m is preferred. The main properties required for the liquid absorbing layer are physical and chemical strength, as well as liquid permeability and elasticity. These properties are adjusted to a desired range by laminating a single nonwoven fabric. If it is difficult, the elasticity and the liquid absorption in the lower layer,
It is preferable to laminate the layers so that the strength is developed in the upper layer.

The layer having elasticity and conductivity relating to the liquid absorbing roll of the present invention is constituted by a single layer composed of a single composition or a mixture of a plurality of types of compositions constituting a layer having both elasticity and conductivity. Or a layer composed of a single composition or a mixture of a plurality of compositions, and may be formed by laminating layers having one of the characteristics of elasticity and conductivity in any order, or a combination thereof. It is good also as lamination.

In the composition for forming the layer having elasticity and conductivity according to the present invention, the material exhibiting at least elasticity may be various kinds of conventionally known rubbers whose material itself has elasticity, and the material itself does not necessarily have elasticity. Resins and metals which do not have are mentioned. In the present invention, in order to express elasticity by using a material which does not necessarily have elasticity itself, the material is formed into a fibrous shape, and then a woven fabric, a knitted fabric, a net shape, or a nonwoven fabric shape as described above. Processed into a web, and then wrapped in a long length, or made into a sheet and laminated, or a plasticizer component or a flexible component used in combination with these materials, when pre-molded or laminated on a roll shaft At this time, a method of blowing a gas into the inelastic material or foaming the gas so as to generate a gas from the inside during the molding process to form a so-called sponge, a method of combining these, and the like are included.

The rubbers used in the layer having at least elasticity according to the present invention include natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), alphin rubber, styrene butadiene rubber (SBR), and high styrene. Rubber, ethylene-propylene rubber, chlorosulfonated polyethylene rubber (CSM), acrylic rubber (ACM / ANM), urethane rubber (U), butyl rubber (IIR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), isoprene -Acrylonitrile rubber, epichlorohydrin rubber, silicone rubber (Q), fluoro rubber (FKM), polysulfide rubber (TR) and the like.

The resin composition used for at least the layer having elasticity according to the present invention may be the same as the composition used for the liquid absorbing layer, such as polyvinyl chloride, polyvinylidene chloride, or the like.
Examples thereof include polyolefin-based, polyacrylonitrile-based, polyamide-based, polyester-based, and polyvinyl alcohol-based resins, and are preferably formed into a fibrous layer. These may be mixed and used as needed. In addition to the above compositions, natural fibers such as wood and non-wood (bamboo, kenaf, etc.) pulp, regenerated and semi-synthetic fibers such as rayon fibers and acetate fibers, various metal fibers, ceramic fibers, rock wool fibers, glass fibers Also, inorganic fibers such as alumina fibers, zirconia fibers, silicon nitride fibers, silicon carbide fibers, and carbon fibers may be used in combination.

On the other hand, in the composition constituting the layer having elasticity and conductivity according to the present invention, at least the material exhibiting conductivity includes various kinds of conductive metals and conductive carbon (fibrous, granular, etc.). ) And the like. Examples of a method for imparting conductivity to the layer having elasticity and conductivity include at least mixing (kneading) of a conductive material with a composition having elasticity and surface coating (plating).

More specifically, when the elastic layer is made of a material having elasticity such as rubber, or a material which exhibits elasticity by foaming, that is, a so-called sponge, the conductive material is contained in these materials. A method of forming a layer after mixing the raw materials in the form of particles (powder) or the like may be used. Also, in order to express elasticity and conductivity using a material that does not necessarily have elasticity and conductivity, a process in which the material is processed into a web after being formed into a fibrous shape, and further laminated to express elasticity,
That is, a method of treating the fiber surface in at least any one of the fiber stage, the web stage, and the lamination stage in the same manner as the conductivity of the liquid-absorbent layer. And a method of laminating, and a method of mixing conductive fibers in a web forming process.

The preferred structure of the layer having elasticity and conductivity according to the present invention is to use NBR as the material having elasticity and mix conductive fine particles with the material to exhibit conductivity, or to form a metal layer on the elastic layer. The one provided with is good. As a measure of the conductivity of the elastic layer made conductive by blending conductive fine particles, the volume resistivity is about 10 ² to 10 ⁸ Ω · cm, preferably about 10 ³ to 10 ⁶ Ω · cm. It is. Examples of the conductive particles include conductive carbon particles and metal particles such as nickel, iron, and aluminum.

Further, the metal layer provided on the elastic layer may be formed by plating or by meshing metal fibers vertically and horizontally,
What laminated | stacked in the sheet form which the metal fiber was entangled at random is preferable. When a material that cannot be laminated with a metal layer by plating is used for the elastic layer, or when the metal layer is to be formed at a particularly low cost, a metal foil may be wound around the elastic layer to form the metal layer. As a material used for the metal layer laminated on the elastic layer, a material that is not deteriorated by a liquid developer component that absorbs liquid is desirable.
In addition to copper, silver, aluminum, and alloys containing these as main components, stainless steel and the like can be mentioned. In the configuration in which the metal layer is provided on the elastic layer, the elastic layer does not necessarily have to be conductive, and the material forming the elastic layer is N
BR and polyurethane are preferred.

In order to make the layer having elasticity and conductivity permeable to the liquid developer similarly to the liquid absorbing layer, a method of laminating the above fibrous web as a layer having elasticity and conductivity or a method of foaming the material may be mentioned. Can be When the liquid developer permeability is developed by the foaming method, the specific gravity is preferably about 0.1 to 0.5 with respect to the solid material not fired, but the layer having elasticity and conductivity according to the present invention. Even if is provided by a foaming method, since the liquid absorbing layer is further provided on this layer, the surface shape of the layer having elasticity and conductivity does not immediately affect the development state, and is used for laminating the liquid absorbing layer. As long as there is no adverse effect,
The pore diameter of the pores formed by foaming may be large.

The layer having elasticity and conductivity may be subjected to punching and drilling after lamination, or after forming the material constituting the layer into a sheet, and then punching, meshing, electric discharge machining, and drilling. Processing such as processing may be performed, and this may be laminated on a roll shaft to exhibit liquid developer permeability. When subjected to these processing, the cross-sectional area of the holes obtained thereby, preferably 0.5 to 30 mm ^2, further 1 to 20 mm ² is preferred. The pitch of the holes is preferably 1 to 10 mm. Among these processes, in particular, a punching process is performed, and a hole having a circular shape and a cross-sectional area of 5 to 10 mm ² is used in terms of both strength and liquid developer component permeability. Excellent and preferred.

The layer having elasticity and conductivity in the liquid absorbing roll of the present invention may be composed of a material and a layer structure to be used, that is, a layer having elasticity and conductivity, or at least an elastic layer and a conductive layer may be separately laminated. Depending on whether or not, and depending on the method of developing the liquid developer permeability, the characteristics vary greatly,
Since the characteristics of the liquid absorbing roll are almost determined by the liquid absorbing layer, the thickness of the layer having elasticity and conductivity is not greatly affected by the material and the layer configuration, and the entire layer having elasticity and conductivity is not affected. Is preferably about 2 to 30 mm, and more preferably 5 to 30 mm.
２５25 mm is preferred.

In particular, when a layer having elasticity and conductivity is separately laminated on at least an elastic layer and a conductive layer, the conductive layer is not easily broken by contraction of the elastic layer.
And within a range that does not significantly impede the elastic performance of the elastic layer,
When the metal is laminated in a net shape or a sheet shape, the thickness is set to 0.
1 to 5 mm is preferable, and 0.3 to 2 mm is more preferable. Moreover, when laminating | stacking a metal foil or performing metal plating, 20-500 micrometers is preferable.

The layer having elasticity and conductivity is combined with the layer having elasticity and conductivity according to the present invention in order to suppress oxidation due to long-term use and to prevent induction of electrolysis and electric corrosion by the liquid developer component. It is also preferable to provide a protective layer having an electrolysis resistance and an electric corrosion resistance between the liquid layer and to form a multilayer. The protective layer of the layer having elasticity and conductivity is required to have not only dissolution resistance in a liquid developer but also electrolytic resistance and electric corrosion resistance. Include metal oxides such as aluminum oxide, magnesium oxide, and nickel oxide; metal fluorides such as aluminum fluoride and magnesium fluoride; and resins such as polyvinylidene chloride, polyvinyl chloride, and polyfluoroethylene. .

As a method for forming the protective layer, there is a method in which a material for forming the protective layer is dissolved or dispersed in a liquid that does not dissolve the layer having elasticity and conductivity and applied. In the case of a material having a poor self-film-forming property such as the above-mentioned metal oxide, a binder may be used in combination. However, when the layer having elasticity and conductivity is made liquid developer permeable similarly to the liquid absorbing layer, the liquid developer permeability is impaired by completely covering the surface of the layer having elasticity and conductivity. It is important to take care not to have them.

The roll shaft used in the liquid-absorbing roll of the present invention is not limited to a material which does not deteriorate the liquid developer due to contact with the liquid developer component, and which is not essentially corroded by the liquid developer component, or has a surface which is liquid. It is desirable to use a material that is plated or coated with a material that does not interact with the developer. As the material of the roll shaft according to the present invention, stainless steel and aluminum alloy are preferable, but depending on the necessity of mechanical strength, a material obtained by plating chromium on structural carbon steel also has a small amount of deflection in actual use. Preferred for.

As the other material of the roll shaft according to the present invention, a synthetic resin may be used as long as it has sufficient mechanical strength and does not dissolve or swell due to the liquid developer component. Examples of the synthetic resin used for the roll shaft include polyamide resin, phenol resin, acrylic resin, hard polyvinyl chloride, urea resin, and epoxy resin. Further, a structure in which a fibrous substance is solidified with a synthetic resin may be used, and a roll shaft formed by FRP may be used. However, in the liquid absorbing roll of the present invention, it is necessary to apply a bias voltage to the image carrier, but if the application from the bias voltage applying means is performed via the roll axis, the material of the roll axis may be used. Is required to be electrically conductive in addition to the above characteristics. When a material other than metal is used, at least the roll shaft surface must be electrically conductive.

In the case where the layer having elasticity and conductivity has a structure through which the liquid developer can pass, and the liquid developer component is removed outside the roll via the liquid absorbing layer and the layer having elasticity and conductivity. The roll shaft has a hollow structure from the portion where the layer having elasticity and conductivity is provided to at least one shaft end, and the portion of the roll shaft where the layer having elasticity and conductivity is further provided with the liquid developer. It is necessary to have a structure that transmits light.
Therefore, it is necessary to have a through hole at least in a portion where the layer having elasticity and conductivity is provided. The shape of the through-hole does not matter, but the cross-sectional area of the hole secures the rigidity of the roll shaft,
And 0.5 to 20 m in the sense of transmitting the liquid developer component.
m ² is preferable, and 2 to 10 mm ² is preferred. Further, the pitch is preferably 1 to 10 mm, more preferably 2 to 10 mm.
5 mm is preferred.

In particular, if a layer having elasticity and conductivity is provided after the roll shaft is formed, a through hole may be provided integrally after providing the layer having elasticity and conductivity. . In this case, if the whole perforated area is to be constant, it is desirable to perforate more holes having a smaller cross-sectional area. On the other hand, if a material having a structure having many holes, such as a punching metal, an expanded metal, and a mesh, is used as a portion of the roll shaft where at least the layer having elasticity and conductivity is provided, holes are formed later. Since it is not necessary, it is preferably used.

The diameter of the roll shaft according to the present invention needs to be increased as the length is increased in consideration of the amount of deflection of the roll and the like, but it is generally about 10 to 40 mm and 12 to 40 mm.
30 mm is preferred. The diameter of the liquid-absorbing roll according to the present invention, which is formed by laminating a layer having elasticity and conductivity and a liquid-absorbing layer substantially concentrically on this roll axis in this order, is 17
About 90 to 90 mm, preferably about 28 to 65 mm. The hardness of the roll is preferably about 20 to 40 degrees, and more preferably 25 to 35 degrees, as measured by a spring-type hardness tester A type specified in JIS K6301.

When the roll shaft has a hollow structure and continuously absorbs liquid, the roll shaft, the layer having elasticity and conductivity have a structure that allows the liquid developer component to pass through, and of course, the liquid developer suction liquid collection. It is necessary to connect the vacuum means to the hollow shaft end via the means.

The concentration of the toner particles contained in the liquid developer having absorbed the liquid is selectively adjusted, that is, the toner particles are positively left on the image carrier, and have a charge other than the toner particles such as a carrier liquid. The liquid developer component that does not exist is excluded from the liquid absorbing layer of the liquid absorbing roll or the roll outside the roll, so that a bias voltage can be applied to the liquid absorbing roll according to the present invention. It is important that the bias voltage is applied in the present invention so that the relative movement of the toner particles between the toner and the surface of the image carrier becomes substantially zero. And a bias voltage having the same polarity as the above. The specific bias voltage application conditions cannot be specified because they vary greatly depending on the charging potential of the image carrier, the development conditions, the electrical characteristics of the toner particles in the liquid developer, and the like, but they have the same polarity as the charge of the toner particles. And at most about twice the charging potential of the image carrier, generally 2
It is about 0 to 800V.

The voltage application from the bias voltage applying means to the liquid absorbing roll may be performed directly on the elastic and conductive layer or the metal layer on the elastic layer, or may be applied to the metal roll shaft. May be. Further, the voltage application may be provided so as not to disturb the conveyance of the image carrier and other processing, and the shape of the contacting portion is a brush shape, a spring piece shape, a A shape that can reduce friction, such as a shape in which a bearing is fitted into a roll shaft, is preferable.

[0071]

The liquid-absorbing roll of the present invention is obtained by laminating a layer having elasticity and conductivity and a liquid-absorbing layer substantially concentrically on the roll axis in this order. It is made of a nonwoven fabric whose upper layer has been subjected to a three-dimensional entanglement treatment. The liquid-absorbing layer can be formed by simply winding the nonwoven fabric to the required thickness on the layer having elasticity and conductivity, so that lamination is easier than the foam rubber used for the liquid-absorbing layer of the conventional liquid-absorbing roll. At the same time, if the function deteriorates due to abrasion due to use over time or contamination by liquid, it is sufficient to rewind a considerable part, and the function can be recovered simply and in a short time. In addition, the surface property and degree of liquid absorption of the liquid-absorbing roll can be improved by using nonwoven cloths having different fiber types, fiber diameters, or degrees of entanglement, or by laminating two or more nonwoven cloths having different densities and thicknesses. Can be controlled freely. Further, the elasticity of the roll can be changed by changing the number of windings (thickness of the liquid absorbing layer) and the winding strength of the nonwoven fabric.

The nonwoven fabric used for the liquid absorbing layer is a nonwoven fabric in which fibers are three-dimensionally entangled by applying a mechanical treatment to a web once formed. The fibers are entangled with each other and develop strength without adding a binder, and the fibers are bent and entangled up and down.As a result, the voids expand up and down, resulting in an elastic nonwoven fabric rich in voids. When used for a layer, it is possible to provide stable liquid absorption, liquid retention, and strength that can withstand long-term use. Further, by forming the nonwoven fabric in the liquid absorbing layer to have a structure in which there is no step on the outer peripheral surface of the roll, the unevenness of the developing step which occurs depending on the outer peripheral length of the roll can be prevented.

Further, by forming a layer having elasticity and conductivity in the liquid-absorbing roll by laminating a metal layer on the elastic layer, an elastic layer provided around the roll shaft and provided on the outer periphery thereof are provided. A conductive metal layer, and a liquid absorbing layer provided on the outermost periphery respectively provide adhesion between an image carrier and a liquid absorbing roll, generation of an electric field on toner particles contained in a liquid developer,
Since the respective properties of the liquid absorbing property and the abrasion resistance are shared, each design is limited according to the purpose, so that a high-performance liquid absorbing roll can be provided.

Further, the layer having elasticity and conductivity and the roll shaft have a structure through which the liquid developer component can pass, and the portion of the roll shaft provided with the layer having elasticity and conductivity from at least one shaft end. By having a hollow structure, if vacuum means is connected to the hollow shaft end of this roll shaft,
The liquid developer is drained out of the roll via the liquid absorbing layer, the layer having elasticity and conductivity, and the roll axis, and can continuously absorb a large amount of liquid. By applying, the continuous liquid absorbing step while selectively concentrating or removing the charge holding component contained in the liquid becomes possible, and the liquid absorbing layer and the layer having elasticity and conductivity become the liquid developer. Residuals can be prevented.

[0075]

EXAMPLES The present invention will be described with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

Example 1 Nonionic surfactant was prepared using a polyester fiber having a fineness of 0.15 denier and a fiber length of 7.5 mm and a polyester fiber having a fineness of 3 denier and a fiber length of 20 mm at a weight ratio of 6: 4. It was put into water together with the agent, and vigorously stirred with a pulper. When the fiber bundle is gone, add water to dilute it,
While slowly stirring with an agitator, a polyacrylamide solution as a viscosity modifier was added to increase the viscosity, and a fiber slurry 1 uniformly dispersed was obtained. Non-woven fabric 1 was obtained from this slurry 1 by using an inclined short-mesh paper machine so as to have a basis weight (dry weight) of 40 g / m ² .

Next, this nonwoven fabric 1 was mounted on a stainless steel wire mesh support of 100 mesh equivalent, and a water stream was jetted from above the nonwoven fabric 1 to entangle the fibers. The confounding was carried out once for each of the front and back sides using five nozzle heads equipped with nozzles. Table 1 shows the nozzle (water flow) diameter of each head,
Shows nozzle (water flow) spacing and pressure. However, a head having head number 5 on both sides used a low-pressure, thin water flow for surface adjustment. After the completion of the three-dimensional entanglement, the resultant was dried at 130 ° C. using an air through dryer to obtain a three-dimensional entangled nonwoven fabric 2.

[0078]

[Table 1]

A polyester fiber having a fineness of 0.1 denier and a fiber length of 10 mm, a fineness of 1 denier and a fiber length of 15 mm
Low melting point heat-fusible fiber having a core-sheath structure (manufactured by Unitika);
Melty # 4080, sheath part: polyethylene terephthalate copolymer core part: polyethylene terephthalate) was used in a ratio of 6: 4 (weight ratio) to obtain a slurry 2 of fibers uniformly dispersed in the same manner as described above. Using this slurry 2,
Non-woven fabric 3 was obtained by making a paper with an inclined short-mesh paper machine so that the basis weight was 25 g / m ² .

Next, this nonwoven fabric 3 was loaded on a stainless steel wire mesh support of 100 mesh equivalent in the same manner as in the production of the three-dimensionally entangled nonwoven fabric 2.
except for changing the 125 kg / cm ² from kg / cm ² Table 1
Under the conditions described above. After three-dimensional confounding,
It dried at 130 degreeC using the suction drum dryer, and the three-dimensional entangled nonwoven fabric 4 was obtained.

A 2 mm-thick SUS304 punching metal having a circular through hole with a diameter of 3 mm and a pitch of 5 mm was used to form a cylinder having an outer diameter of 16 mm on the roll shaft portion on which the layer having elasticity and conductivity was provided. A hollow support shaft is provided at one end of a punched metal cylinder and a solid support is provided at the other end, so that the roll shaft has a hollow structure from the portion provided with the layer having elasticity and conductivity to one shaft end. A support shaft was mounted and fixed to produce a roll shaft. In addition, a vacuum means for removing the liquid developer having absorbed the liquid to the outside of the roll can be connected to the shaft end of the hollow support shaft.

An acrylonitrile-butadiene rubber kneaded with conductive carbon particles (volume resistivity: about 10 ³ Ω · cm) is formed on the roll shaft as an elastic and conductive layer.
Was formed into a foamed shape having a thickness of 6 mm so as to allow liquid to pass therethrough. On the layer having elasticity and conductivity, the three-dimensionally entangled nonwoven fabric 2 produced above was wound without wrinkles or slack so as to have a thickness of 3 mm. Further, the three-dimensionally entangled nonwoven fabric 4 was started to be wound from the end of the winding so that the ends were connected to each other, and was wound without wrinkles or looseness so as to have a thickness of 1 mm to provide a two-layered liquid absorbing layer. In addition, the winding start end and the winding end end of both nonwoven fabrics were cut obliquely to the winding direction so that both ends became spiral on the roll surface. In addition, the end of winding of the three-dimensional entangled nonwoven fabric 4 is fixed by melting the low-melting heat-fusible fiber so that there is no step on the outer peripheral surface of the roll,
A liquid absorbing roll 1 was produced.

Example 2 Polyolefin-based composite fibers (Chisso EA, core PP, sheath EVA) having a fiber length of 2 denier and a fiber length of 15 mm were prepared using MK-
The fiber was immersed in a 40-fold diluted aqueous solution of 160 (Muromachi Chemical Cleaner Conditioner) at 25 ° C. for 1 minute, and the fiber was filtered and washed with water. Next, the fiber was immersed in a three-fold diluted aqueous solution of MK-660 (Muromachi Chemical Microetching Solution) at 50 ° C. for 5 minutes, and the fiber was filtered and washed with water. Subsequently, the fiber is
The fibers were immersed in a pre-dip solution of an aqueous hydrochloric acid solution, and the fibers were filtered. This fiber was immersed in a 32-fold diluted solution of MK-260 (Muromachi Chemical's catalyst solution) at 25 ° C. for 10 minutes, washed with filtered water, and further diluted with a 10-fold diluted solution of MK-360 (Muromachi Chemical's accelerator). It was immersed at 30 ° C. for 8 minutes, filtered, washed with water and catalyzed.

Next, the fiber was treated with sodium citrate 20
kg / m ³ and an aqueous solution of sodium hypophosphite 2 kg / m ^{3, and} an aqueous solution of nickel sulfate 224 kg / m ³ and sodium hypophosphite 226 kg / m ³ and sodium hydroxide 85 k
g / m ³ aqueous solutions were separately dropped and stirred, and electroless nickel plating was performed by a dropping method, followed by filtration and washing to obtain conductive organic short fibers. At this time, the temperature of the plating solution is 5
It was 0 ° C.

97 parts by weight of the conductive organic short fibers were impregnated with a 1% nonionic dispersant solution. Next, 3 parts by weight of hot water-soluble polyvinyl alcohol fiber was impregnated in a 1% nonionic dispersant solution. These were put into water, stirred with a high-speed mixer for 3 minutes to disintegrate the fibers, and then gently stirred in a chest equipped with a reciprocating rotary stirrer (Agiter, manufactured by Shimazaki Seisakusho Co., Ltd.). Then, immediately, an aqueous solution of polyacrylamide was appropriately added, followed by gentle stirring to prepare a slurry 3 of uniformly dispersed fibers. The slurry 3 was used to make a nonwoven fabric 5 by making an inclined short-mesh paper machine with a basis weight of 50 g / m ² .

Next, two layers of the nonwoven fabric 5 are laminated, and a stainless steel support of 100 mesh is placed below the nonwoven fabric 5.
The fibers were entangled by a columnar water flow using three nozzle heads having the conditions shown in Table 2, and the polyvinyl alcohol fibers were eluted. Similarly, the same processing was performed on the back surface. The entangled sheet was dried at 100 ° C. using a suction through dryer to obtain a three-dimensional entangled conductive nonwoven fabric 6.

[0087]

[Table 2]

Next, the three-dimensional entangled conductive nonwoven fabric 6 is cut, and its periphery is sandwiched between frames, and nickel sulfate 240 k
g / m ³ , nickel chloride 45 kg / m ³ , boric acid 30 kg /
An electro-nickel plating solution containing m ³ , saccharin 2 kg / m ³ , and 1,4-butynediol 200 g / m ³ was immersed in the center of a container circulating at 50 ° C., and 100 A was placed between the nickel counter electrodes on both sides. Was applied for 15 minutes to perform electric nickel plating.

The electro-nickel-plated three-dimensional entangled conductive non-woven fabric 6 is wound around the roll shaft having the hollow structure produced in Example 1 so as to have a thickness of 7 mm without wrinkles or slacks. Was formed. On this layer having elasticity and conductivity, the three-dimensionally entangled nonwoven fabric 4 prepared in Example 1 was wound without wrinkles or looseness so as to have a thickness of 3 mm to provide a liquid absorbing layer. In the same manner as in Example 1, the winding start end and the winding end end of the nonwoven fabric were cut diagonally with respect to the winding direction so that both ends were spirally formed on the roll surface. Further, the end of the winding of the three-dimensionally entangled nonwoven fabric 4 was melted and adhered and fixed to the low melting point heat fusible fiber in the same manner as in Example 1 to produce a liquid absorbing roll 2.

Example 3 Using the roll shaft having the hollow structure produced in Example 1, a urethane foam having a thickness of 6 mm was provided thereon, and a copper mesh was further laminated thereon to form a layer having elasticity and conductivity. Was provided. A space is provided at the end of the copper mesh in the roll width direction so that a bias voltage can be applied, and Crambon KBC60 (a nonwoven fabric made of Kurabo Industries, a main component polyester) is formed to a thickness of 3 mm on a conductive layer. Wrap it without wrinkles or slack, and start winding the three-dimensional entangled nonwoven fabric 4 produced in Example 1 from the end of this winding, and the thickness is 1 mm.
The liquid absorption layer having a two-layer structure was formed by winding without wrinkles or slack so that The winding end of the three-dimensional entangled nonwoven fabric 4 is temporarily fixed with a water-soluble glue, and then a nylon ultrafine thread is spirally wound around the entire outer periphery. After the washing, the liquid absorbing roll 3 was produced.

Comparative Example 1 The non-woven fabric 3 before the three-dimensional entanglement treatment was replaced with the three-dimensional entangled non-woven fabric 4 used for the liquid absorbing roll 1 prepared in Example 1.
Was wound to form the uppermost layer of the liquid absorbing layer. That is, in Example 1, the three-dimensional entangled nonwoven fabric 2 was wound on a layer having elasticity and conductivity made of acrylonitrile-butadiene rubber kneaded with conductive carbon particles so as to have a thickness of 3 mm. Then, the nonwoven fabric 3 was started to be wound from the end of the winding so that the ends were connected to each other, and wound so as to have a thickness of 1 mm without wrinkles or slack to provide a liquid absorbing layer having a two-layer structure. The liquid absorbing roll 4 was produced in the same manner as in Example 1 with respect to the winding form at the winding end and the method of bonding and fixing the nonwoven fabric 3.

Comparative Example 2 The three-dimensional entangled nonwoven fabric 2 produced in Example 1 was formed to a thickness of 7 mm without providing a layer having elasticity and conductivity on the roll shaft having the hollow structure produced in Example 1. The three-dimensional nonwoven fabric 4 prepared in Example 1 is wound so that the end is connected from end to end, and is wound without wrinkles or slack so as to have a thickness of 3 mm. Was. The liquid absorbing roll 5 was produced in the same manner as in Example 1 with respect to the winding form at the winding end end and the method for bonding and fixing the nonwoven fabric 3D.

Comparative Example 3 A liquid absorbing layer was formed by using the urethane foam used in Example 3 in place of the liquid absorbing layer in the liquid absorbing roll 3 produced in Example 3. That is, a urethane foam having a thickness of 6 mm was provided on the roll shaft having a hollow structure prepared in Example 3, and a copper mesh was further laminated thereon to form a layer having elasticity and conductivity (the copper mesh roll width direction). At both ends, a conductive treatment was applied to the roll support shaft so that a voltage could be applied directly from the roll shaft.), And a urethane foam containing no conductive member was laminated thereon to a thickness of 4 mm. Thus, a liquid absorbing roll 6 was produced.

Using the liquid absorbing rolls 1 to 6 manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, two developing units were respectively assembled as a pair of upper and lower units at the outlet side of the developing electrode to produce developing devices. Vacuum means is connected to shaft ends of the hollow support shafts of the upper and lower liquid absorbing rolls via a liquid developer recovery tank. Contact terminals from bias voltage applying means are arranged on the exposed copper mesh portion of the liquid absorbing roll 3 and on a support shaft of the other liquid absorbing rolls so that a bias voltage can be applied. The bias voltage was adjusted so that the relative movement of the toner particles with the surface of the image carrier became substantially zero.

As an image carrier for forming an electrostatic latent image,
Aluminum support with hydrophilic treatment (thickness 0.3mm)
A lithographic printing plate provided with a photoconductive layer thereon (hereinafter abbreviated as an electrophotographic plate), and a metal conductive layer and a photoconductive layer on a composite substrate of glass fiber and epoxy resin (thickness 1.6 mm) in this order. Was developed using a printed circuit board (hereinafter, abbreviated as a printed board). The printed circuit board is
Each sheet has through holes at 1000 locations.

In order to confirm the influence of the liquid absorbing roll on the toner image and the liquid absorbing ability, in the electrophotographic plate after development,
The degree of the disturbance of the toner image and the remaining amount of the liquid developer due to the poor squeezing of the developer was evaluated (in the table, described as “toner disturbance”). Similarly, after development of the printed circuit board, the photoconductive layer other than the toner image area was eluted, and the ratio (%) of disconnection failure in the through-hole portion when the metal conductive layer outside the etching resist was removed by etching was determined. (In the table, described as defect ratio). Further, in a cycle in which 25 printed circuit boards are continuously developed and then stopped for 1 hour, 200 sheets per day,
After a total of 1000 sheets were developed per day, the degree of residual liquid developer on the surface of the liquid-absorbing roll contacted with the image carrier development and the abrasion resistance were evaluated (described as surface condition in the table). Table 3 also shows the results.

[0097]

[Table 3]

The liquid-absorbing property of the liquid developer in the above-mentioned liquid-absorbing roll is such that the conventional squeezing roll having no liquid-absorbing ability tends to remain. Also, the electrophotographic plate having a flat electrostatic latent image forming surface has a better liquid absorbing performance as compared with the one using the urethane foam when the nonwoven fabric is used as the liquid absorbing layer of the liquid absorbing roll. In the development, the liquid developer hardly remained in the non-image area irrespective of the presence or absence of the three-dimensional entanglement treatment of the nonwoven fabric.

Further, by subjecting the nonwoven fabric to the three-dimensional confounding treatment, the pore diameter becomes large and uniform and the liquid permeability is improved despite the strength being improved. In the case of using the nonwoven fabric subjected to the three-dimensional entanglement treatment as the uppermost layer of the liquid absorbing roll (liquid absorbing rolls 1 to 3), no through-hole defect was induced. The non-woven fabric that had not been subjected to the original entanglement treatment (the liquid absorbing roll 4) induced through-hole defects.

Even if a nonwoven fabric subjected to a three-dimensional entanglement treatment is used as the uppermost layer of the liquid absorbing roll, but has no conductive layer below it (liquid absorbing roll 5), the non-image area Although the liquid developer containing the toner hardly remained, the through-hole defect was better than when the liquid absorbing roll 4 was used, but the relative movement of the toner particles with the surface of the image carrier was substantially reduced. In some cases, disturbance was induced in a part of the formed toner image, possibly because the toner image could not be maintained at zero.

In the case of using the urethane foam as the uppermost layer of the liquid absorbing roll instead of the nonwoven fabric subjected to the three-dimensional entanglement treatment (liquid absorbing roll 6), the uniformity of the liquid absorbing is poor, and the liquid development The agent remained uneven. In particular, the disconnection failure of the through hole was the worst among the used liquid absorbing rolls.

In any case, since at least one through hole defect does not function as a circuit, the liquid absorbing rolls 4, 5, and 6, which cause the through hole defect, need to develop at least a printed board having a through hole. Is virtually unusable.

On the other hand, a bias voltage is applied to the liquid absorbing roll,
Even if the toner particles in the liquid developer are prevented from entering the pores, the liquid developer is vacuumed, but the toner particles will eventually remain in the porous layer, and the absorption of the toner over time and the toner Since the roll surface may be rubbed or worn due to the induction of particles sticking or the sliding contact with the image carrier many times, the liquid developer remains on the liquid absorbing roll surface after the development of 1,000 sheets. And the abrasion resistance and the like.

As a result, the roll (liquid-absorbing roll 4) using a nonwoven fabric on which the uppermost layer of the liquid-absorbing layer has not been subjected to the three-dimensional entanglement treatment hardly induces the liquid absorption inhibition and the sticking of the toner particles over time. However, the fluff generated on the surface of the nonwoven fabric due to the development of a large number of sheets becomes cocoon-shaped, and the contact between the liquid absorbing roll and the image carrier, which is the object to be developed, is deteriorated. Increased. In addition, even if a nonwoven fabric subjected to a three-dimensional confounding process is used, a non-woven fabric having no conductive layer underneath (liquid absorbing roll 5) is excellent in abrasion resistance, and is excellent in abrasion resistance between the liquid absorbing roll and the image carrier. Little change in contact,
With the passage of time, fixation of the toner particles to the liquid absorbing layer was induced, and the liquid absorbing property was reduced. Further, the one using urethane foam for the liquid absorbing layer (liquid absorbing roll 6) was also excellent in abrasion resistance,
Because of the easiness of being compatible with the toner particles, the adhesion of the toner particles to the liquid-absorbing layer, particularly the surface thereof, was induced with the passage of time, and the liquid-absorbing property was reduced.

On the contrary, a non-woven fabric subjected to a three-dimensional entanglement treatment was used as the uppermost layer of the liquid absorbing layer (liquid absorbing roll 1).
Each of (3) to (3) is excellent in abrasion resistance, does not cause inconveniences such as sticking of toner particles and inhibition of liquid absorption due to the toner particles, and has very good absorption even with the lapse of time and in the development of a large number of sheets. It had liquid performance.

[0106]

As described above, a three-dimensional entanglement treatment is performed as the uppermost layer of a liquid absorbing roll in which a layer having elasticity and conductivity and a liquid absorbing layer are laminated in this order substantially concentrically on the roll axis. By using the nonwoven fabric, not only the excellent liquid absorbing performance and the effect of applying a voltage to the conductive member, but also the disturbance of the image formed on the image carrier is prevented,
Disconnection of the through-hole portion of the printed wiring board having the through-hole was able to be avoided. Non-woven fabric that has been subjected to three-dimensional confounding treatment is more resistant to wear than when other materials are used, and even if it is worn over time or if it is contaminated by liquid, the three-dimensional It has an excellent effect that the function can be easily restored simply by replacing the entangled nonwoven fabric portion.

Claims (4)

[Claims] 1. A liquid absorbing roll for supplying a liquid developer to an image carrier on which an electrostatic latent image is formed and developing the same, and then removing an excess liquid developer on the image carrier, comprising a roll shaft. In a liquid absorbing roll formed by laminating a layer having elasticity and conductivity and a liquid absorbing layer substantially concentrically in this order, the liquid absorbing layer is made of a nonwoven fabric, and at least the uppermost layer is subjected to a three-dimensional entanglement treatment. A liquid-absorbing roll, which is a coated nonwoven fabric. 2. The liquid absorbing roll according to claim 1, wherein the layer having elasticity and conductivity is obtained by laminating a metal layer on the elastic layer. 3. The layer having elasticity and conductivity and the roll shaft have a structure through which a liquid developer component can be transmitted, and at least one of a portion of the roll shaft provided with the layer having elasticity and conductivity. 2. The liquid absorbing roll according to claim 1, wherein the end has a hollow structure. 4. The liquid-absorbing roll according to claim 1, wherein the nonwoven fabric in the liquid-absorbing layer has a structure with no step on the outer peripheral surface of the roll.