JP2002116630A - Intermediate transferring member and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly form an image on an intermediate transfer member, in eliminating the processing stage for stabilizing the image before transferring, as well as to efficiently transfer the formed image on recording medium. SOLUTION: This intermediate transferring member 1 is provided with a porous body 3 formed by such as a PTFE on a surface, in which releasing agent 2 like silicone oil is impregnated on a base material 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate transfer member and an image forming apparatus provided with the same.

[0002]

2. Description of the Related Art Image forming apparatuses applicable to facsimile machines, printers, copiers and the like include a serial system, a drum system and an intermediate transfer system.

For example, a serial type ink jet recording apparatus forms an image by reciprocating a recording head in a direction perpendicular to a conveying direction of a recording medium such as paper. However, this image forming apparatus requires a long printing time.

In the drum method, an image is formed while a recording medium is held on a drum and the drum is rotated at a high speed, so that the printing time can be reduced. As a method of holding the recording medium on the drum, a gripper method, a negative pressure adsorption method, and the like are known, but all of them have complicated mechanisms, increase the size of the apparatus,
Weight. As a method for holding a recording medium on a drum with a relatively simple configuration, a method using electrostatic force is also known. However, in order to print a high-quality image, an electrostatic field gives an ink ejection performance. Measures are needed to reduce the adverse effects.

Further, as a common drawback of the serial system and the drum system, there is a problem that the recording head is easily deteriorated. This occurs because the print head and the print medium are arranged close to each other, and the print medium comes into contact with the print head or is generated from the print medium due to a transport error of the print medium or use of a non-standard print medium. Foreign matter (paper powder) causes nozzle clogging.

[0006] The intermediate transfer method solves the above-mentioned drawbacks, but the image must be accurately formed on the intermediate transfer member and the image must be efficiently transferred to a recording medium. An example of such an image forming apparatus is disclosed in
Japanese Patent No. 6750 discloses an image forming apparatus that forms an image with an ultraviolet curable oil-based ink on an intermediate transfer member having a thin film of a glycerin aqueous solution formed on a smooth surface, and then transfers the image to a recording medium. I have. In addition, Japanese Patent Application Laid-Open
No. 89067 discloses that the HLB value is 2 to 2 on a smooth surface.
In the intermediate transfer member on which a thin film of 15 surfactants is formed,
An image forming apparatus that forms an image with an aqueous ink and transfers the image to a recording medium is disclosed. The intermediate transfer members disclosed therein have the above-mentioned thin film formed on the surface thereof and function as a release layer, so that they have good transfer efficiency.

[0007] However, the image on the liquid thin film is unstable, and a step for increasing the viscosity and stabilizing the image before transferring it to a recording medium is required.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is not necessary to stabilize an image before transfer, and an image can be accurately formed on an intermediate transfer member. It is an object of the present invention to provide an intermediate transfer type image forming apparatus capable of efficiently transferring a transferred image to a recording medium, and an intermediate transfer member used for the same.

[0009]

According to a first aspect of the present invention, there is provided:
An intermediate transfer member used to transfer an image formed on the surface to a recording medium, the intermediate transfer member having a porous material impregnated with a release agent on the surface. This porous body is preferably ink-repellent.

A second aspect of the present invention is an intermediate transfer member used for transferring an image formed on the surface to a recording medium, wherein the intermediate transfer member has an ink-repellent porous body on the surface. Intermediate transfer member.

It is preferable that these porous bodies have a three-dimensional network structure. Specifically, it is preferable that the polynomial body is formed of a fluororesin or a polyolefin resin. Further, the average pore size of the polynomial body is 0.01 to 1
It is preferably 00 μm.

Preferably, the release agent is an ink-repellent, non-volatile liquid which is incompatible with the ink for forming an image. Specifically, the release agent preferably contains silicone oil.

[0013] Further, a third aspect of the present invention is the above-mentioned intermediate device.
This is an image forming apparatus provided with a transfer member. Images like this
Examples of the forming device include an ink jet recording device.
You. When the intermediate transfer member of the first aspect is used,
The image forming apparatus replenishes the intermediate transfer member with a release agent.
Preferably, it further comprises means. This replenishment means
Place the molding compound on the opposite side of the surface of the intermediate transfer
When replenishing from the surface, the replenishing means contacts the porous body.
A second porous body. Also, replenishment means
Is sliding or driven by the porous body of the intermediate transfer member, or
Sliding or following the porous substrate integrated with the porous body
Can be Adjust the pore size of the porous body of the intermediate transfer member.
r₁, The contact angle between the porous body of the intermediate transfer member and the release agent is θ₁,
The pore size of the second porous body is r_Two, And separated from the second porous body.
The contact angle of the mold_TwoAnd the intermediate transfer member and the second
At the contact portion with the porous body, (cos θ₁/ R₁)>
(Cos θ _Two/ R_TwoIs preferable.

In the first aspect of the present invention, the release agent impregnated in the porous body forms a meniscus in the fine pores on the surface of the porous body. If the distance between the fine holes is sufficiently smaller than the size of the ink particles (primary particle diameter of the droplets or toner particles), the state is substantially similar to the state in which the surface of the intermediate transfer member is covered with the liquid film of the release agent. Can be realized.

Since this release agent is subjected to the capillary force of the micropores of the porous body, it is slightly different from the liquid film of the release agent formed on the intermediate transfer member having a smooth surface as in the prior art. It does not move or flow easily even under external force.

The ink particles come into contact with the intermediate transfer member at a contact angle exceeding 90 ° due to the ink repellent effect of the release agent. At first glance, it seems to be an unstable adhesion state, but since the release agent that comes into contact with the ink particles forms a meniscus between the ink particles and the porous body, the interfacial tension acting on the ink particles stably holds the ink particles Acts as a force.

The fine uneven structure on the surface of the porous body also has the effect of stabilizing the ink particles.

As described above, the ink particles are held on the intermediate transfer member by the effect of the meniscus formed by the release agent and the uneven structure of the surface of the porous body to such an extent that the ink particles do not move due to vibration or impact generated in the image forming apparatus. At the same time, since the toner is attached to the intermediate transfer member at a contact angle exceeding 90 ° due to the ink repellent effect of the release agent, 100% is transferred from the intermediate transfer member to the recording medium.

Also in the second embodiment of the present invention, the ink particles come into contact with the surface of the porous material having ink repellency at a contact angle of more than 90 °. At first glance, it seems to be an unstable adhesion state, but the movement and coalescence of the ink particles is suppressed on the surface of the porous body in contact with the ink particles, in other words, the ink particles do not spread. For this reason, a high quality image can be formed on the intermediate transfer member. Further, the ink particles are held to such an extent that the image is not disturbed by the vibration or impact generated in the image forming apparatus due to the effect of the uneven structure on the surface of the porous body. For this reason,
The image formed on the intermediate transfer member is kept stable.
Since the surface of the ink-repellent porous body has high releasability when the image on the intermediate transfer member is transferred to the recording medium, the ink particles do not remain on the intermediate transfer member, and
00% is transferred. As described above, high-speed and high-quality transfer can be performed.

In the present invention, the ink contains at least an aqueous ink jet ink and a powder toner for electrophotography.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

As shown in FIG. 1, the intermediate transfer member 1 according to the first embodiment of the present invention has a porous body 3 impregnated with a release agent 2 on its surface. Further, the intermediate transfer member 100 according to the second embodiment of the present invention has an ink-repellent porous body 102 as shown in FIG. Intermediate transfer member 1, 100
May have a cylindrical shape or a belt shape.

A substrate (4 in FIGS. 1 and 7) is used as necessary for the intermediate transfer member of the present invention. As the material of the base material, any material can be used as long as it can stably maintain the surface layer and can stably maintain the contact state with the transfer means via the recording medium, such as aluminum, metal such as stainless steel, ceramic, and resin. Either material can be used.

When the intermediate transfer member is brought into contact with replenishing means described later, a porous substrate can be used. The porous substrate is formed of a material having sufficient mechanical strength and capable of continuous use at high speed for a long period of time. This porous substrate is integrated with the porous body, but when this integration is performed by applying a predetermined heat and pressure [melt compression bonding (thermal lamination) method], the porous substrate is used as an intermediate. A material that melts at a temperature equal to or lower than the melting point of the porous body of the transfer member is selected. For example,
When a PTFE resin is used as the porous body, the porous base material has a melting point equal to or lower than the melting point of the PTFE resin, that is, 230 to
Uses non-woven fabric, woven fabric, mesh, net, etc. formed of a polyolefin resin (eg, polyethylene resin, polypropylene resin, etc.), nylon resin, polyester resin, aramid resin, etc. and a composite material thereof that melts at 250 ° C. or less. it can.

When the porous substrate and the porous body are integrated with an adhesive, the same material as the porous body of the intermediate transfer member can be used as the porous substrate. In this case, as the adhesive, a thermoplastic adhesive, a thermosetting adhesive, or a room-temperature adhesive can be used. Specifically, a combination of an imide-based, epoxy-based, cyanate ester-based, polyamide-based, phenol-based room-temperature adhesive and a silicone elastomer has a sufficient adhesive strength to a low surface energy material, and It is suitable because it is chemically stable and has excellent chemical resistance and environmental resistance. At the time of bonding, if the porous body and the porous base material are separated by the adhesive layer, the release agent cannot be supplied to the porous body. Striped,
It is necessary to apply the coating in a grid or the like at a distance, and to secure a communication path from the supply means to the porous body.

It is preferable that the interval between the fine holes of the porous body is sufficiently smaller than the size of the ink particles (6 in FIGS. 1 and 7). If this condition is satisfied, a structure in which isolated holes are discretely present, a fine groove structure in which microfibers are woven,
A structure in which materials having a capillary structure such as hollow fibers are bundled,
Any of a three-dimensional network porous structure may be used. Among these, a three-dimensional network porous structure is preferable. If the distance between the micropores is smaller than the size of the ink particles, the porous body forms a meniscus (5 in FIG. 1) in the micropores on the surface by impregnating with a release agent, and substantially removes the surface. It can be covered with a liquid film of the release agent. In addition, if a three-dimensional network-like porous structure is used, the release agent can be quickly and uniformly penetrated into the porous body simply by supplying the release agent to an arbitrary portion of the porous body. .

The average pore size of the porous body is 0.01 to 100 μm.
m is preferable. If the average pore size is less than 0.01 μm, the release agent is less likely to penetrate the porous body, and a special method such as a pressurization method is required to impregnate a predetermined amount of the release agent. On the other hand, if the average pore diameter exceeds 100 μm, the meniscus holding force is reduced, and as a result, the release agent may flow out to the surface of the porous body due to external force such as vibration or impact. In the present invention, the average pore size is measured by a mercury intrusion method. When the intermediate transfer member of the present invention is used in an ink jet recording apparatus, the average pore diameter is 0.1 to 30 μm.
Is more preferable, and when it is used for an electrophotographic recording apparatus, the thickness is more preferably 0.05 to 5 μm.

The porosity of the porous body is 10 to 90%.
It is preferable that If the porosity exceeds 90%, the mechanical strength is insufficient, and if the porosity is less than 10%, the exposure ratio of the porous body increases, and the effect of the release agent is not exhibited. The porosity is measured by a mercury intrusion method.

The above average pore diameter range and porosity range are preferable even in the case of a porous body having ink repellency.

In the intermediate transfer member according to the first aspect of the present invention,
Since the release agent impregnated in the porous body exhibits a release function at the time of image transfer, the release properties of the porous body itself need not be high, and mechanical properties such as tensile strength are excellent. Or you can choose cheap materials.
In order to further improve the transfer efficiency, the porous body is preferably ink-repellent. In the intermediate transfer member according to the second aspect of the present invention, the porous body needs to be ink-repellent. In order for the porous body to exhibit ink repellency,
It is necessary that the surface tension of the porous body is smaller than the surface tension of the ink. Specifically, the surface tension of the porous body is 4
It is preferably at most 0 mN / m, more preferably at most 30 mN / m, even more preferably at most 20 mN / m.

The material of the ink-repellent porous body is P
TFE (ethylene tetrafluoride polymer), PFA (ethylene tetrafluoride / perfluorovinyl ether copolymer), P
Fluororesins such as VDF (polyvinylidene fluoride), FEP (ethylene tetrafluoride / propylene hexafluoride copolymer), ETFE (ethylene / tetrafluoroethylene copolymer), PCTFE (polyethylene chloride trifluoride) Polyolefin resins such as PE (polyethylene), PP (polypropylene), and PB (polybutylene). Other materials for the porous body include polysulfone resins such as polysulfone polymers; polyester resins such as PET (polyethylene terephthalate) and PBT (polybutylene terephthalate); nylons (6, 6-6,
6-2, 12) and the like; polyamide resins such as polyimide and polyamide imide; polyurethane resins; polyacrylonitrile polymer, methacrylic acid alkyl ester, N-alkyl (meth) acrylamide, carboxy (meth) acrylate and the like. Polyacrylic resin; polystyrene resin such as hydroxystyrene resin;
Polyketone resin such as polyetherketone resin; Silicone resin such as silicone gel; Ethylene / vinyl acetate copolymer (EVA); Polyvinyl chloride resin; Polyvinylidene chloride resin; Polycarbonate (PC); Polyoxymethylene (POM) ; Polyphenylene sulfide (P
PS); polyetheretherketone (PEEK); and fibrous resins such as ethyl cellulose, cellulose acetate, cellulose nitrate, and cellulose propionate. These can be used alone or in combination of two or more.

Among these, fluorinated resins such as PTFE are preferred because of their high chemical resistance and heat resistance and excellent ink repellency. Polyolefin-based resins such as polyethylene have the same chemical resistance and ink repellency as fluorine-based resins, and are excellent in mechanical strength, and therefore are particularly preferable as a material for forming a belt-shaped intermediate transfer member. .

As a method for forming the porous body,
Known production methods such as a foaming method, a sintering method, a stretching method, an extraction method, a track etching method, a melt phase separation method, and a phase change method can be used, and an optimum method is selected according to the material. For example, a porous body can be obtained by melting or dispersing various additives in the above-described material, molding the obtained melt or dispersion, and then removing the additives. Further, a porous body can be obtained by subjecting a temporarily molded article formed of the fine particles of the above material and various additives to a heat treatment and a stretching treatment near the melting point of the above material. When a fluororesin is used, it is preferable to use a stretching method or an extraction method that does not perform a heat treatment at or above the melting point of the resin.

When the porous body is provided on the substrate, it is preferable to wind the film-shaped porous body around the substrate or to apply the porous body on the substrate in the form of a film. Further, the film itself may be formed into an endless belt, and the base material may be omitted.

When the porous body is formed of a resin other than the fluorocarbon resin, the fluorocarbon resin may be applied to the porous body by spraying, dipping or the like.

The release agent used in the present invention is preferably ink-repellent, that is, the surface tension of the release agent is preferably smaller than the surface tension of the ink. Further, it is desirable that the surface tension is small in order to impregnate the fine pores of the porous body. Specifically, the surface tension of the release agent is preferably 30 mN / m or less.

The release agent used in the present invention is preferably non-volatile so that the impregnation state of the porous body does not change. Specifically, the vapor pressure of the release agent is set to room temperature (25 °
It is preferable that C) is not more than about 13.3 Pa (0.1 mmHg).

Further, the release agent used in the present invention is preferably incompatible with the ink for forming an image. Specifically, the solubility of the release agent in the ink,
It is preferably 0.1% by weight or less at room temperature (25 ° C.).

The kinematic viscosity of the release agent used in the present invention is preferably in the range of 1 to 1000 mm ² / s at room temperature. When the kinematic viscosity is less than 1 mm ² / s, the amount of release of the release agent at room temperature increases, making it difficult to maintain the performance of the intermediate transfer member for a long period of time. On the other hand, when the kinematic viscosity exceeds 1000 mm ² / s, the release agent becomes difficult to flow, and the time required for impregnation into the porous body becomes longer.

As the release agent, organic solvents and oils which are liquid at ordinary temperature can be suitably used. Specifically, octane,
Organic solvents such as nonane, tetradecane, dodecane, oleic acid, linoleic acid, n-decanol, dimethylbutanol, dibutyl phthalate and dibutyl maleate, and oils such as vegetable oils, mineral oils, silicone oils and fluorine oils are preferably used. be able to. These may be used alone or in combination of two or more as long as they can be mixed uniformly. Further, a plurality of materials may be mixed to adjust the viscosity and the surface tension to a preferable range.

Among these, silicone oils having excellent properties described above are preferable.

When joining the above-mentioned porous material layer and the base material, an adhesive can be used. The adhesive is preferably one that has resistance to the release agent and can bond a material having a high release property. Specifically, silicone-based adhesives, PFA,
A fluorine-based adhesive such as FEP, a urethane-based adhesive, or the like can be used. Further, the porous material layer and the base material may be joined by heat fusion.

In the intermediate transfer member of the present invention, an intermediate layer may be provided between the substrate and the porous material layer. Examples of the intermediate layer include a primer layer for improving adhesiveness and an elastic layer for improving the contact state between the recording medium and the intermediate transfer member during transfer.

The intermediate transfer member of the present invention can be applied to an intermediate transfer member of an intermediate transfer type image forming apparatus. Examples of such an image forming apparatus include an inkjet recording apparatus and an electrophotographic recording apparatus. Both image forming apparatuses are
The image forming apparatus includes a recording unit that imparts an image on the intermediate transfer member of the present invention.

In the case of an ink jet recording apparatus, this recording means discharges ink droplets in accordance with a print signal, and specific examples include an ink jet recording head using an electrothermal transducer or a piezoelectric element.

In the case of an electrophotographic recording apparatus, the recording means generally includes a photoreceptor, charging means such as a corotron for uniformly charging the photoreceptor, and an electrostatic latent image formed on the photoreceptor. And a developing means for visualizing the electrostatic latent image with powder toner. The recording means may further include a cleaning means such as a static elimination means or a blade which comes into contact with the photoreceptor. As a recording unit that does not use a photoconductor, there is a direct recording type that controls the movement of powder toner in accordance with a print signal, and more specifically, a toner jet type and a contrography type.

Further, the image forming apparatus is provided with transfer means for transferring an image on the intermediate transfer member to a recording medium. When the image forming apparatus is an ink jet recording apparatus, the transfer unit is of a contact type in which a recording medium is brought into contact with an intermediate transfer member, but when the image forming apparatus is an electrophotographic image forming apparatus using powder toner, The transfer means includes a contact type and a non-contact type in which the recording medium is not brought into contact with the intermediate transfer member.

As the contact type, a roll disposed at a position facing the intermediate transfer member of the present invention and rotatable in accordance with the movement of the recording medium can be used. In this case, the interval between the roll and the intermediate transfer member is set to be shorter than the thickness of the recording medium, whereby the recording medium is pressed against the intermediate transfer member with a predetermined pressure and comes into contact.

In the case where the image forming apparatus is an ink jet recording apparatus, since the ink particles are liquid, the image can be transferred only by bringing the recording medium into contact with the intermediate transfer member. In the case of an apparatus, before transfer, the ink particles are liquefied by heating or the like and then brought into contact with a recording medium.

As a non-contact type, there is a means for applying an electrostatic force exceeding the adhesive force between the ink particles and the intermediate transfer member during transfer. Examples of such a device include a charger such as a corotron and an electric field forming means such as a bias roll.

According to the present invention, since the image formed on the intermediate transfer member is transferred 100% to the recording medium, it is not always necessary to provide a cleaning means. However, the transfer to the recording medium due to a trouble such as a paper jam is not performed. The device may shut down before completion. In this case, it is necessary to clean the image remaining on the intermediate transfer member. Therefore, the image forming apparatus preferably includes a cleaning unit for cleaning the surface of the intermediate transfer member. As cleaning means,
A blade formed of a rubber material can be used.
Further, an image may be absorbed by using an ink-absorbing sponge as a cleaning unit. In any case, since the surface of the intermediate transfer member has high releasability due to the effect of the release agent, it can be easily cleaned. The cleaning unit may be in constant contact with the intermediate transfer member to clean the intermediate transfer member each time an image is formed, or may contact the intermediate transfer member only when a trouble such as a paper jam occurs.

Since the release agent used in the present invention is retained in the micropores of the porous body, the amount transferred to the recording medium together with the image at the time of transfer is very small, but the consumption amount increases as printing is repeated. Increase. Even if the amount of the release agent is slightly reduced, the meniscus of the release agent is recovered by the capillary force of the porous body. However, in order to guarantee a longer device life, the case where the intermediate transfer member of the first embodiment is used. Preferably, the image forming apparatus includes a replenishing unit for replenishing the intermediate transfer member with a release agent.

As the replenishing means, any of non-contact type such as spray, contact type such as coating roll, pad, wick (7 in FIG. 2), porous body (for example, sponge) and the like may be used. Can be. In the case of the contact type, the replenishing means is partially immersed in the release agent (9 in FIG. 2) contained in the storage container (8 in FIGS. 2 and 3), and the other is partially immersed in the intermediate transfer member. It is arranged to contact the surface. Among these, a porous body whose replenishing amount can be easily adjusted is preferable.

In the case of a coating roll, this coating roll may be driven by rotation of the intermediate transfer member, or may be rotated independently of rotation of the intermediate transfer member.

The porous body is preferably a resin-made porous body produced by stretching, rolling, foaming or the like. Specific examples include so-called foams such as a fluororesin porous body produced by stretching and rolling, a polyolefin resin porous body, a polyurethane foam produced to have open cells by foaming, polyethylene foam, and polystyrene foam, and foamed rubbers. Is mentioned. Further, a material having a continuous void porous structure in which continuous fine grooves on the surface or inside can contact the porous body of the intermediate transfer member on the surface, such as a fiber material or a paper material, can also be suitably used. As such,
The sponge, non-woven fabric, felt, cloth and the like are mentioned.
These materials are not deteriorated or deteriorated by the release agent used, the pore diameter of the porous body of the intermediate transfer member is r ₁ , the contact angle between the porous body of the intermediate transfer member and the release agent is θ ₁ , Assuming that the pore diameter of the porous body is r ₂ and the contact angle between the porous body and the release agent is θ ₂ , (cos θ ₁ / r ₁ )> (cos
θ ₂ / r ₂ ) is preferably satisfied. When this formula is satisfied, the release agent held by the replenishing unit can be supplied to the intermediate transfer member by bringing the porous body of the replenishing unit into contact with the porous body of the intermediate transfer member.

The replenishment may be performed every time an image is formed, or when a certain period of time has elapsed or when a certain number of image formations have been completed. When a multicolor image is formed, replenishment may be performed each time an image of each color is formed, or replenished when formation of a multicolor image is completed. When the replenishing unit is not replenished each time an image is formed, the replenishing unit is connected to the moving member and can be moved from a position close to the intermediate transfer member to a position separated from the intermediate transfer member. Is placed at

This replenishing means is preferably arranged downstream of the cleaning means in the rotation direction of the intermediate transfer member.

When the image forming apparatus has a replenishing means, the image forming apparatus may further include a replenishing amount regulating means in order to prevent the release agent from being excessively replenished to the intermediate transfer member. When the replenishing means is an application roll, as shown in FIG. 3, the replenishing amount regulating means comes in contact with the outer peripheral surface of the application roll 10 to adjust the amount of the release agent 9 on the application roll. And a blade which is disposed downstream of the replenishing means in the rotation direction of the intermediate transfer member and contacts the intermediate transfer member to scrape off excess release agent. When the replenishing means is a porous body, the porous body can serve as both the replenishing means and the replenishing amount regulating means.

When the intermediate transfer member is a belt, the image forming apparatus includes a plurality of rolls for winding and rotating the belt-shaped intermediate transfer member. In this case, it is preferable that image formation, transfer, and replenishment of the release agent are performed at positions facing each roll.

When the width of the recording means is smaller than the width of the recording medium (for example, when printing is performed by scanning a short recording head in the width direction of the recording medium) or when a multicolor image is formed, It is necessary to rotate the intermediate transfer member a plurality of times to form an image on the intermediate transfer member. In such a case, a means that comes into contact with the intermediate transfer member to exhibit its function,
For example, the replenishing unit, the transferring unit, the cleaning unit, and the replenishing amount regulating unit are connected to the moving member so that the replenishing unit can be arranged at a position away from the intermediate transfer member until a completed image is formed on the intermediate transfer member. Is also good.

As shown in FIG. 11, the replenishing means may replenish the release agent on the surface of the intermediate transfer member opposite to the surface on which the image is formed. In this case, the size of the image forming apparatus can be reduced. The replenishing means may use a gravity or a pressure mechanism (not shown) to drop the release agent in a non-contact manner with the porous body of the intermediate transfer member as shown in FIG. 11, but as shown in FIGS. Alternatively, a contact type may be used.

In FIG. 12, the replenishing means slides on the surface of the porous body of the intermediate transfer member opposite to the surface on which the image is formed. By pressing the replenishing means and the intermediate transfer member under pressure,
A stable contact state can be maintained. With such a replenishing means, it is easy to secure a contact surface with a sufficient area,
The entire supply means can be reduced in size. The release agent (especially silicone oil) used in the present invention has a small surface tension and also has a performance as a lubricant. Therefore, the rotation accuracy of the intermediate transfer member, which causes damage due to sliding and deteriorates image quality, is reduced. A drop or the like can be avoided.

When the replenishing means and the intermediate transfer member are slid, as shown in FIG. 15, the replenishing means may be slid with the porous base material integrated with the porous body of the intermediate transfer member. Good. In that case, the life of the intermediate transfer member can be made longer, and the reliability can be improved.

In FIG. 13, the replenishing means follows the surface of the intermediate transfer member opposite to the surface on which the image is formed on the porous body. In this case, there is no danger that a problem due to abrasion will occur, and when the intermediate transfer member is an endless belt as shown in FIG. 14, the replenishing means can be used as a stretching roll. Cost reduction can be achieved by reducing the number of parts.

In FIGS. 12 to 15, the replenishing means is disposed so as to face the recording head, but the replenishing means does not need to face the recording head.

FIG. 4 shows a specific configuration of the above image forming apparatus.
To 6.

The image forming apparatus 20 shown in FIG. 4 is an ink jet recording apparatus and includes a drum-shaped intermediate transfer member 22 that can rotate clockwise. The intermediate transfer member 22 has on its surface a porous body impregnated with a release agent, around which a recording head 24, a pressure roll 26 as a transfer unit, and one end are connected to the intermediate transfer member 22 clockwise. The cleaning blade 28 in contact with the release agent 32 stored in the storage container 30 is partially in contact with the release agent 32, and the other part is in contact with the intermediate transfer member 22.
Roll 34 as a replenishing means that comes into contact with the blade, blade 3 as a replenishing amount regulating means that comes into contact with the intermediate transfer member 22
6 are arranged. Pressure Roll 26 and Intermediate Transfer Member 2
2 is set smaller than the thickness of the recording medium 38.

The image forming apparatus 40 shown in FIG. 5 is also an ink jet recording apparatus. Note that the same components as those of the image forming apparatus 20 of FIG.
In the image forming apparatus 40, the intermediate transfer member 42 is a belt, and is wound around a plurality of rollers 44 disposed at positions facing the recording head 24, the pressure roll 26, and the application roll 34. The intermediate transfer member 42 also has a porous body impregnated with a release agent on its surface.

The image forming apparatus 50 shown in FIG. 6 is an electrophotographic recording apparatus and includes a housing 52. In the housing 52, a belt-like intermediate transfer member 54 wound around a plurality of rollers and rotatable counterclockwise, and a photoreceptor 56 that contacts the intermediate transfer member 54 and can rotate clockwise are provided. ing. This intermediate transfer member 54 also has on its surface a porous body impregnated with a release agent. Around the photoconductor 56,
Clockwise, a charger 58 for charging the photoreceptor 56, a developing device 60 for supplying powder toner onto the photoreceptor 56, a photoreceptor 56
Cleaner 62 and photoreceptor 56 for removing toner remaining on
Is provided. The photoconductor 5 is located at a position where the photoconductor 56 and the intermediate transfer member 54 are in contact with each other.
A transfer device 66 for attracting an image on the photoconductor 56 onto the intermediate transfer member 54 is disposed so as to face the transfer member 6.

The image forming apparatus 50 includes, as exposure means 68, a laser recording apparatus 70 for irradiating laser light, a collimator 72 for converting the irradiated laser light into parallel light, and a polygon mirror 74 for polarizing parallel light. And a correction lens 76 for correcting the polarized light.
Is irradiated on the region of the photosensitive member 56 between the charger 58 and the developing device 60.

Further, the image forming apparatus 50 has a recording medium 38.
Tray 78 for taking out the recording medium 38 from the supply tray 78, and a plurality of pairs of conveying rollers 8 for conveying the recording medium 38 to the intermediate transfer member 54
2, 84, and a belt conveyor 88 for transporting the recording medium 38 from the intermediate transfer member 54 to a discharge tray 86 provided outside the housing 52. Among a plurality of rollers around which the intermediate transfer member 54 is wound, a voltage is applied between the intermediate transfer member 54 and the recording medium 38 as a transfer unit at a position facing a roller 90 disposed near the conveyance path of the recording medium 38. Bias roller 92 for applying the recording medium 3
8 passes the nip portion between the roller 90 and the bias roller 92 together with the intermediate transfer member 54 so that the image is recorded on the recording medium 38.
Is transferred to

A fixing device 94 for melting and fixing an image on the recording medium 38 is provided downstream of the intermediate transfer member 54 in the transport direction of the recording medium 38.

Further, a cleaning blade 96 for removing residual toner on the intermediate transfer member 54 and a replenishing agent for the intermediate transfer member 54 are provided downstream of the roller 90 in the moving direction of the intermediate transfer member 54. Application roll 98
Is provided.

In these image forming apparatuses 20, 40, 50, the intermediate transfer member 22,
A predetermined amount of release agent is supplied to the porous body layers of 42 and 54,
Impregnated and retained. The release agent forms a meniscus in micropores existing on the surface of the porous body.

Then, the intermediate transfer member 2 is
An image is formed on 2, 42, 54. Image forming apparatus 2
At 0 and 40, the recording head 24 is moved to the intermediate transfer members 22 and 42.
The image is formed directly on the photosensitive member 5 in the image forming apparatus 50.
The image (toner image) formed on 6 is transferred onto the intermediate transfer member 54 by electrostatic transfer. Intermediate transfer member 22, 4
The images on 2 and 54 adhere to the surface of the intermediate transfer member at a contact angle of 90 ° or more due to the ink repellent effect of the release agent and the ink repellent effect of the porous body, and are formed between the release agent and the image. Due to the surface tension of the meniscus of the release agent and the effect of the uneven structure of the surface of the porous body, the release agent adheres with a restraining force that does not move even if it receives some external force.

This image contacts the recording medium 38 conveyed at a predetermined timing at the transfer position and is transferred to the recording medium 38. When the image is formed of liquid ink, the image is transferred onto the recording medium 38 only by contact with the recording medium 38, and the recording medium 38 is pressed against the intermediate transfer members 22 and 42 to ensure the transfer. It is pressed by the roll 26. When the image is formed of powder ink (toner), the image is transferred onto the recording medium 38 by using electrostatic force.

After the transfer, the surfaces of the intermediate transfer members 22, 42, 54 are cleaned by the cleaning blades 28, 96. Next, a release agent is supplied to the porous bodies of the intermediate transfer members 22, 42, 54 by the application rolls 34, 98, and the supply amount of the release agent is adjusted by the blade 36.

The above operation is repeatedly performed.

In these image forming apparatuses 20, 40 and 50, the cleaning blades 28 and 96 can be omitted. When an intermediate transfer member provided with an ink-repellent porous body on its surface is used, the storage container 30, the release agent 32,
The application rolls 34 and 98 and the blade 36 can be omitted.

FIG. 8 shows such an image forming apparatus 110. The image forming apparatus 110 includes the intermediate transfer member 22
4 except that the cleaning blade 28, the storage container 30, the release agent 32, and the application roll 34 are omitted. It is the same, and the description is omitted.

In these apparatuses, the releasing agent is supplied from the surface of the intermediate transfer member opposite to the image forming surface instead of the application rolls 34 and 98 as a supply means.
Needless to say, the configuration shown in FIG. 15 may be used.

[0082]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. Example 1 An 85 μm-thick porous PTFE film (average pore size: 1.0 μm) manufactured by a uniaxial stretching method was applied to an aluminum pipe by an ink jet recording apparatus shown in FIG.
μm, porosity 80%) and heat-treated at a temperature equal to or higher than the melting point of PTFE to adhere the film to the pipe,
Silicone oil (surface tension 20mN) on TFE film
/ M, kinematic viscosity 20 mm ² / s, vapor pressure 0.1 at 25 ° C.
An intermediate transfer member impregnated with Pa or less (less than the measurement limit, solubility in ink at 25 ° C. 0% by weight), a thermal inkjet head (short head), a foamed polyurethane roll as a replenishing means, and an aluminum roll as a transferring means (Having the same width as the paper width), a strip blade made of ethylene propylene rubber was used as a cleaning means. In addition, as the ink, four color aqueous inks of black, cyan, magenta, and yellow (surface tension of 40 mN /
m (for all four colors)). The contact angle between the intermediate transfer member and the ink was 100 °.

Using this ink jet recording apparatus, the image could be transferred to the recording medium without increasing the viscosity of the image on the intermediate transfer member. The transfer rate was 100%. Example 2 A 40 μm-thick porous polypropylene film (average pore size 0.2 μm, porosity 46%) produced by a uniaxial stretching method was placed on a 100 μm-thick PET film on the inkjet recording apparatus shown in FIG. The film is bonded to the pipe by heat treatment at a temperature equal to or higher than the melting point of silicone oil (surface tension 20 mN / m, kinematic viscosity 20 mm ² / s) on the porous polypropylene film.
Was used. This intermediate transfer member was wound around a first roll arranged at a position facing the recording head, a second roll arranged at the transfer position, and a third roll arranged at the supply position. Other conditions were the same as in Example 1. The contact angle between the intermediate transfer member and the ink was 100 °.

Using this ink jet recording apparatus, the image could be transferred to the recording medium without increasing the viscosity of the image on the intermediate transfer member. The transfer rate was 100%. (Example 3) In an ink jet recording apparatus shown in FIG. 8, a porous PTFE film (average pore diameter 0.5
μm, porosity of 80%), heat-treated at a temperature equal to or higher than the melting point of PTFE, and bonded an intermediate transfer member with a film to a pipe, a thermal inkjet head (short head),
An aluminum roll (having the same width as the paper width) was used as a transfer unit. As the ink, aqueous inks of four colors of black, cyan, magenta, and yellow (surface tension: 40 mN / m (for all four colors)) were used. The contact angle between the intermediate transfer member and the ink was 110 °.

Using this ink jet recording apparatus, the image could be transferred to the recording medium without increasing the viscosity of the image on the intermediate transfer member. The transfer rate was 100%. The image on the recording medium obtained by this embodiment is shown in FIG.
And high image quality equivalent to that printed directly on the recording medium. Comparative Example 1 The same ink jet recording apparatus and ink as in Example 3 were used except that an intermediate transfer member using a non-porous PTFE film was used. Example 3
However, since the ink particles moved and joined on the intermediate transfer member, a high quality image could not be formed on the intermediate transfer member. The image on the recording medium obtained in Comparative Example 1 is shown in FIG. 10, and the dot size and shape are changed as compared with the image obtained in Example 3 (FIG. 9).
Image information could not be faithfully reproduced. (Example 4) In the ink jet recording apparatus shown in FIG. 16, an adhesive mainly composed of an epoxy resin was arranged in isolated points on a non-woven fabric of a polyethylene resin having an average pore diameter of 100 μm as a porous base material. Average pore size 1.0μ
m, a porosity of 80%, and a thickness of 85 μm after pressing a porous PTFE, and then curing the adhesive at room temperature to integrate the porous base material and the porous body into a piece having a width of 215 mm and a circumference of 3
A 15 mm endless belt was used as an intermediate transfer member.

5 mm thick on the outer circumference of the aluminum roll
And a replenishing means was manufactured. Silicone oil (surface tension 20 mN /
m, kinematic viscosity 20 mm ² / s, vapor pressure 0.1 P at 25 ° C.
a (less than the measurement limit), the solubility in ink at 25 ° C. 0% by weight (measurement limit).

An endless belt was wound around the supply means and the stretching roll. In addition, a thermal inkjet head (short head) and a rubber roll (having the same width as the paper width) as a transfer unit were used. In addition, as ink, black,
Aqueous ink of four colors of cyan, magenta and yellow (surface tension 35 to 40 mN / m (for all four colors), kinematic viscosity 3 mm ² /
s (for all four colors)). The contact angle of the release agent to the porous PTFE was 30 °, the contact angle of the release agent to the porous substrate was almost 0 °, and the contact angle of the release agent to the polyurethane foam was almost 0 °. there were. Also,
The peripheral speed of the intermediate transfer member was 1000 mm / s, and the writing system was a helical scan system in which printing was performed by the interaction between the intermediate transfer member rotating a plurality of times and a recording head moving linearly in a direction perpendicular to the paper surface.

Using this ink jet recording apparatus, continuous printing of 5,000 sheets of A4 paper was performed, and it was confirmed that there was no image quality defect due to ink repelling or merging. Also, no contamination of the intermediate transfer member due to transfer failure occurred, and 100% of the ink image was transferred each time.
From this, it was confirmed that the release agent was properly supplied to the intermediate transfer member from the supply unit.

[0089]

According to the present invention, since an intermediate transfer member having a porous material impregnated with a release agent or an ink-repellent porous material on its surface is used, it is not necessary to stabilize an image before transfer. ,
An image can be accurately formed on the intermediate transfer member, and the formed image can be efficiently transferred to a recording medium.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention in which a three-dimensional mesh-like porous material layer is provided on a base material, and the porous material layer is impregnated with a release agent.
FIG. 6 is a cross-sectional view of the intermediate transfer member according to the embodiment.

FIG. 2 is a cross-sectional view illustrating an example of a replenishing unit that can be used in the image forming apparatus of the present invention.

FIG. 3 is a cross-sectional view illustrating another example of a replenishing unit usable in the image forming apparatus of the present invention and an example of a replenishing amount regulating unit.

FIG. 4 is a schematic configuration diagram of an image forming apparatus of the present invention.

FIG. 5 is a schematic configuration diagram of another image forming apparatus of the present invention.

FIG. 6 is a schematic configuration diagram of still another image forming apparatus of the present invention.

FIG. 7 shows a second embodiment of the present invention in which a three-dimensional mesh-like porous material layer is provided on a base material, and the porous material layer is impregnated with a release agent.
FIG. 6 is a cross-sectional view of the intermediate transfer member according to the embodiment.

FIG. 8 is a schematic configuration diagram of still another image forming apparatus of the present invention.

FIG. 9 is an image obtained in Example 3.

FIG. 10 is an image obtained in Comparative Example 1.

FIG. 11 is a cross-sectional view illustrating still another example of a replenishing unit usable in the image forming apparatus of the present invention.

FIG. 12 is a cross-sectional view showing still another example of a replenishing unit usable in the image forming apparatus of the present invention.

FIG. 13 is a cross-sectional view illustrating still another example of a replenishing unit usable in the image forming apparatus of the present invention.

FIG. 14 is a cross-sectional view showing still another example of a replenishing unit usable in the image forming apparatus of the present invention.

FIG. 15 is a cross-sectional view showing still another example of a replenishing unit usable in the image forming apparatus of the present invention.

FIG. 16 is a diagram illustrating a schematic configuration of an image forming apparatus used in a fourth embodiment.

[Explanation of symbols]

 1, 22, 42, 54, 100, 112 Intermediate transfer member 2, 9 Release agent 3, 102 Porous body 7 Wick 10, 34, 98 Application roll 20, 40, 50, 110 Image forming apparatus

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Suemitsu 430 Green Tech Nakai, Nakai-cho, Ashigara-kami, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. Co., Ltd. F-term (reference) 2C056 FA03 FA04 FD13 JB18 2H032 BA09 BA23

Claims (18)

[Claims] 1. An intermediate transfer member used for transferring an image formed on its surface to a recording medium, the intermediate transfer member having a porous material impregnated with a release agent on its surface. 2. The intermediate transfer member according to claim 1, wherein the polynomial material has ink repellency. 3. The release agent according to claim 1, wherein the release agent has ink repellency.
Or the intermediate transfer member according to 2. 4. The intermediate transfer member according to claim 1, wherein the release agent is a non-volatile liquid that is incompatible with ink for forming an image. 5. The intermediate transfer member according to claim 1, wherein the release agent contains silicone oil. 6. An intermediate transfer member used for transferring an image formed on the surface to a recording medium, the intermediate transfer member having a surface provided with an ink-repellent porous body. 7. The intermediate transfer member according to claim 1, wherein the porous body has a three-dimensional network structure. 8. The intermediate transfer member according to claim 1, wherein the polyhedral material is formed of a fluororesin or a polyolefin resin. 9. The polynomial body has an average pore size of 0.01 to 1.
The intermediate transfer member according to any one of claims 1 to 8, wherein the intermediate transfer member has a thickness of 00 µm. 10. An image forming apparatus comprising the intermediate transfer member according to claim 1. 11. The image forming apparatus according to claim 10, further comprising a replenishing means for replenishing the intermediate transfer member with a release agent. 12. The image forming apparatus according to claim 11, wherein the replenishing unit replenishes the release agent from a surface of the intermediate transfer member opposite to a surface on which an image is formed. 13. The image forming apparatus according to claim 11, wherein the replenishing means includes a second porous body that contacts the porous body. 14. The image forming apparatus according to claim 12, wherein the replenishing unit slides on the porous body of the intermediate transfer member. 15. The image forming apparatus according to claim 12, wherein the replenishing unit is driven by the porous body of the intermediate transfer member. 16. The method according to claim 12, wherein the intermediate transfer member further includes a porous substrate integrated with the porous body, and the replenishing means slides or follows the porous substrate. Image forming device. 17. The pore size of the porous body of the intermediate transfer member is r ₁ , the contact angle between the porous body of the intermediate transfer member and a release agent is θ ₁ , and the pore size of the second porous body is r ₂ , and when the contact angle between the second porous body and the release agent is θ ₂ ,
The image forming apparatus according to claim 13, wherein (cos θ ₁ / r ₁ )> (cos θ ₂ / r ₂ ) is satisfied at a contact portion between the intermediate transfer member and the second porous body. 18. The image forming apparatus according to claim 10, which is an ink jet recording apparatus.