JPS5977467A - Intermediate transfer material - Google Patents

Abstract

PURPOSE:To obtain a durable intermediate transfer material capable of transferring an excellent image free from deformation and disturbance by incorporating conductive fibers in a substrate made of heat-resistant resin, and preventing high charging of the intermediate transfer material for receiving a toner image on an electrophotographic receptor or the like. CONSTITUTION:Several wt%- several ten wt% conductive fibers 22, such as carbon fibers or metallic fibers, are incorporated in a substrate 20 made of heat- resistant resin, such as polyimide or polyester, and a transfer layer 21 made of silicon type or fluorine rubber is formed on the substrate 20 to prepare the intermediate transfer material 5 for transferring a toner image. The fibers 22 in the material 5 are contained in a state parallel to the advancing direction of the material 5 (arrow 23) or in a lattice form, or several mum- several mm. short fibers 22. The toner is intruded in the recesses of the layer 21 corresponding to the fine roughness of the substrate 20 to transfer the toner image from the photoreceptor to a transfer material, such as transfer paper, with high transfer efficiency. High charging of the material 5 is prevented by the presence of the fibers 22, a copy of good quality is obtained, and its durability is also enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is used to transfer a toner image on an image carrier such as a photoreceptor drum, and further transfer the entire transferred toner image to the next transfer material such as copy paper. In particular, the present invention relates to an intermediate transfer body suitable for electrostatic recording or electrophotographic copying devices.

Conventionally, in recording devices such as electrostatic recording and electrophotography, an electrostatic charge image is formed on an image carrier such as a photoreceptor drum, and this is developed with a developer mixed with toner and, if necessary, carrier. An image is formed based on a process in which the obtained toner image is electrostatically transferred onto a transfer sheet, for example, and further fixed.

However, when a toner image is electrostatically transferred onto a transfer sheet (recording material) using a transfer electrode such as a corona discharger, charge disturbance occurs and the resolution of the toner image is reduced. Furthermore, if a conductive magnetic toner, which has been recently recommended, is used as the toner, the charge will be further disturbed, resulting in a state in which transfer is virtually impossible.

As a method to improve the above-mentioned drawbacks of electrostatic transfer, attempts have been made to press transfer onto a transfer sheet using a suppression roll, but the transfer efficiency is poor and only about half the amount of toner image is transferred. There is a disability.

For example, Japanese Patent Publication No. 46-41679, Japanese Patent Publication No. 48-2
No. 2763, Japanese Unexamined Patent Publication No. 49-78559, and U.S. Patent No. 3,993,825, etc., the above-mentioned toner image is pressure-transferred to a belt-like intermediate transfer member having a rubber transfer layer, and the transferred A method has been proposed in which a toner image is transferred and fixed (transfer-fixed) onto a transfer sheet while being heated and melted using a heating roll.

In such a method, a toner image is suppressed and transferred to the surface layer of a rubber-based transfer layer, such as silicone rubber or fluororubber, which has on the one hand a release property and on the other hand has a property of adhering fine particles when suppressed, and The toner image on this transfer layer is heated and melted by contact with a heating body such as a heating roll, and is transferred under pressure onto a transfer sheet fed at the same time.
It will be established. In other words, the toner image melted by heating is easily transferred and fixed onto the transfer sheet based on the above-mentioned releasability of the transfer layer, so there is no reduction in the resolution of the toner image due to the transfer process, and moreover, the transfer rate is high. is expected to be realized.

As a result of studying known recording devices using such intermediate transfer bodies, the inventors of the present invention found that because the base of a general intermediate transfer belt is made only of a heat-resistant resin film such as polyimide, electric charges are not generated during use. It was discovered that this caused a high charging phenomenon, which adversely affected images. Moreover, the intermediate transfer belt must have a flexible base (having high thermal and mechanical strength) that can withstand repeated use, but this requirement places restrictions on the materials that can be used for the base.

In view of these circumstances, it is an object of the present invention to provide an intermediate transfer member that is effectively prevented from being charged and has sufficient thermal and mechanical strength.

According to the invention, this object is achieved by the intermediate transfer body mentioned at the beginning, which is characterized in that it contains conductive fibers.

According to the present invention, since the intermediate transfer member contains conductive fibers, even if the substrate is to be charged with an electric charge, the electric charge is effectively released through the conductive fibers, as described above. Such a high charging phenomenon does not occur. This particularly improves the transfer from the intermediate transfer member to the next transfer material, making it possible to obtain very good images. In addition, the presence of the conductive fibers improves the thermal and mechanical strength of the intermediate transfer body itself, so that the durability of the intermediate transfer body is significantly improved during repeated use. Therefore, usable substrate materials include strong polyimide, other heat-resistant resins (polyamide, polyamideimide, polyallylsulfone, polyester, arylate resin, etc.), or a mixture of two or more of these. You can choose from a wide range of options.

Such remarkable effects can only be brought about by the inclusion of the above-mentioned conductive fibers according to the present invention. On the other hand, if the intermediate transfer body contains conductive particles or powder particles (e.g., carbon grains) whose shape is completely different from that of fibers, a certain degree of conductivity can be imparted to the intermediate transfer body. However, the carbon grains are likely to peel off, and the intermediate transfer member becomes vulnerable to friction, etc., and its durability becomes unusable.

The conductive fibers used in the present invention are preferably carbon fibers or metal fibers in order to obtain the above-mentioned remarkable effects, and the conductive fibers are preferably arranged along the moving direction of the intermediate transfer body. In particular, mechanical strength is further improved.

In addition, the conductive fibers are arranged in parallel lines with an interval of 15 lines or less,
It is preferable to arrange them in a net or lattice form from the viewpoint of both conductivity and strength. In this case, the fibers may be either single fibers or mixed fibers.

The conductive fiber has a diameter of 1 to 100 μm, and its length may be selected from several μm to several feet. Further, the content of the fibers is suitably, for example, several percent by weight to several tens of percent by weight relative to the base resin.

If fine irregularities are formed on the surface of the transfer layer by containing conductive fibers, toner particles will be sufficiently absorbed into the recesses on the surface of the transfer layer when transferring the toner image from the image carrier to the intermediate transfer member. It is bitten (or bitten), and in combination with the adhesive force of the transfer layer, the transfer efficiency is greatly improved.

The transfer layer is preferably made of silicone rubber, fluororubber, or fluororesin.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings.

First, referring to FIG. 1, an outline of a recording apparatus having an intermediate transfer belt will be explained. In this recording device, a known latent image forming mechanism 2, a developing mechanism 3, and a cleaning mechanism 4 are sequentially provided in the rotational direction in a region along the outer circumferential surface of an image carrier 1 such as a rotating drum type photoreceptor drum. ing. In the transfer area A between the developing mechanism 3 and the cleaning mechanism 4, an intermediate transfer member 5 made of an endless belt is pressed (
It is pressed against the outer circumferential surface of the image carrier 1 by the transfer roller 6. As clearly shown in FIG. 2, the intermediate transfer belt 5 is made of a flexible film substrate made of polyimide or the like having a thickness of 10 to 100 μm, and an adhesive layer 21 of, for example, silicone rubber having a thickness of 10 to 100 μm applied thereto. consists of things.

The intermediate transfer belt 5 is stretched over a pressure roll 6, a heating roll 7 serving as a transfer fixing roll, and a tension roller 8. In the transfer area A, the image carrier 1 is moved at a constant speed in the same direction as the image carrier 1 toward the intermediate transfer body heating area B on the heating roll 7 . In addition, tension roller 8
A cleaning roller 12 is disposed facing the belt 5, and a charge eliminating member 13 such as a charge eliminating brush for preventing the belt 5 from being charged is further provided.

In the transfer and fixing area C at or near the separation point of the intermediate transfer belt 5 on the heating roll 7 , a pressure roll 9 is provided so as to be pressed against the roll 7 . Set to pass through this transfer fixing area C,
A transfer material heating plate 10 is arranged along a transfer material heating area immediately before the transfer fixing area C in a transfer material moving path P of a transfer material made of recording paper.

Using the apparatus configured as described above, in this example, the toner image formed on the image carrier is finally transferred and fixed onto the transfer material in the following manner.

First, the toner image T on the image carrier 1 is formed by developing a latent image formed by the latent image forming mechanism 2 with the developing mechanism 3. That is, when electrophotography is used, the image carrier 1 is composed of a selenium-based, organic compound-based, zinc oxide or cadmium sulfide-based binder type, or other electrophotographic photoreceptor, and the latent image forming mechanism 2 According to
After the entire outer peripheral surface of the image carrier 1 is charged, image exposure is performed to form an electrostatic latent image. When using electrostatic recording, the image carrier 1 is constructed of a dielectric material consisting of a conductive substrate and a dielectric surface layer, and the image signal is converted into an electrostatic latent image using a multi-stylus electrode or an ion control electrode. By doing so, a latent image is formed. Further, when a magnetic recording method is used, the image carrier 1 may be made of a magnetic material, and an image signal may be converted into a magnetic signal by a magnetized head to form a magnetic latent image.

If the latent image formed in this way is an electrostatic latent image, the developing mechanism 3 makes the latent image visible using toner, which is colored charged particles charged to the opposite polarity to the charge forming the latent image. It is considered to be a statue. When the toner used here is a one-component conductive magnetic toner, development is achieved by the charge induced in the toner. - When magnetic brush development is used with conductive toner, the toner layer is formed as a single particle layer or a thin layer close to it, which improves the image quality, durability, and high speed of the final image. It is particularly preferred because it has excellent developability and allows good transfer without selecting a transfer material. When the latent image is a magnetic latent image, it is sufficient to develop it with magnetic toner, and it is possible to prevent the occurrence of blurring of the image during transfer and to obtain a clear image.

The toner image T on the image carrier 1 formed as described above is transferred onto the intermediate transfer belt 5 in the transfer area A by the pressing force of the pressing roller 6.

The adhesive layer of the intermediate transfer belt 5, especially the silicone rubber layer, overcomes the toner retention force of the image carrier 1 in the transfer area A due to the moderate adhesiveness of the surface at low temperatures and the rubber elasticity that contains the toner. Toner can be sufficiently captured on the transfer body side. In addition, since the surface energy of the silicone rubber layer is sufficiently small compared to normal transfer material materials, the toner is heated from the surface of the transfer material side in the transfer fixing area C, which will be described later, and the toner becomes fluid. When the transfer material is brought into pressure contact with the toner, the toner strongly adheres to the transfer material and is almost completely transferred and fixed onto the transfer material.

The heating roll 7 has a heater 7A made of, for example, an infrared lamp built into a hollow metal roll made of aluminum or the like, and controls the temperature of the surface of the metal roll within an appropriate range. As a result, the intermediate transfer belt 5 and the toner image T thereon are heated in the area between the contact start point E with the intermediate transfer belt 5 and the transfer fixing area C, that is, the intermediate transfer body heating area B, and the toner image T on the intermediate transfer belt 5 is heated in the area C. The toner image has sufficient transfer and fixing properties. The pressure roll 9 in the transfer fixing area C is configured as an auxiliary heating roll to further improve transfer fixing properties, and is a heat-resistant elastic roll provided with a surface layer of silicone rubber or the like and equipped with a built-in heater rung 9A. Ru.

Further, the transfer material heating plate 10 in the illustrated example has a shape that is adapted to contact along the outer peripheral surface of the pressure roll 9,
The transfer material is placed between the surface of the pressure roll 9 and the transfer material heating plate 10.
When the transfer material is passed between the intermediate transfer member 5 and the intermediate transfer member 5, the transfer material heating plate 10 contacts and heats the surface of the intermediate transfer member 5 in the transfer fixing area C to such an extent that the toner image on the intermediate transfer member 5 is sufficiently transferred and fixed to the transfer material. Here, the friction coefficient of the surface of the pressure roll 9 is made larger than that of the surface of the transfer material heating plate 10, so that as the surface moves due to the rotation of the pressure roll 9, the surface of the fixed transfer material heating plate 10 is transferred. The material slides, is heated by contact, and is conveyed to the transfer and fixing area C. In the transfer fixing area C, the transfer material heated in this way is sandwiched and pressed between the intermediate transfer belt 5, which has been previously heated together with the toner image by the heat roll 7, and the pressure roller 9. Since it is pressed in a fluidized state by heating, it is reliably transferred and fixed onto the transfer material.

The transfer material that has passed through the transfer fixing area C is normally conveyed along the intermediate transfer belt 5 and separated from the intermediate transfer belt 5 by a tension roller 8 .

Here, if the diameter of the tension roller 8 is made small, the transfer material can be easily separated from the intermediate transfer belt 5, but it is possible to prevent the intermediate transfer belt 5 from shifting by making it swing further. You can also do it. The intermediate transfer belt 5 that has passed through the transfer fixing area C is partially cooled, undergoes transfer again in the transfer area A, and then repeats the transfer fixing process in the transfer fixing area C.

In the figure, reference numeral 11 denotes a cleaning roller, which removes toner when it adheres to the pressure roll 9. As shown in FIGS. 3 and 4, the noteworthy structure of the above-mentioned device is that linear carbon fibers are arranged in a film base made of heat-resistant resin along the base movement director. It means that it is contained or mixed. In the drawings, for ease of understanding, the cross-sections of each layer are omitted (the same applies hereafter), and the carbon fibers are also shown in a simplified manner. Here, the diameter of carbon fiber O is 1 to 100
μm, and its form may be either a single fiber or an itb fiber.

In this way, by containing the carbon fiber n in addition to the base material, even if a charge is to be accumulated during use, the charge easily moves through the conductive carbon fibers 22, so that the base material is highly charged. Moreover, it can be discharged to the outside through the above-mentioned static eliminating member 13 (see FIG. 1). For this purpose, it is desirable that the carbon fibers n have a certain length and are uniformly distributed within the substrate, and the spacing between each carbon fiber is preferably 1511 or less.

In addition to this antistatic effect, the carbon fibers provide sufficient thermal and mechanical strength to the base itself.
The durability of the intermediate transfer belt is improved against repeated use.

This is more than sufficient because the carbon fibers n are arranged along the moving direction of the intermediate transfer member as described above. In addition, since the strength of the base resin is improved, other heat-resistant resins with relatively low strength can be used as the base resin in addition to those with strong holes such as polyimide, which increases the flexibility in selecting the material of the base resin. becomes larger.

In addition, as carbon fiber n, polyacrylonitrile type,
It is possible to use fibers made of vinylon, rayon, pitch, lignin, thermosetting resin, etc., which are carbonized by high temperature treatment according to known methods.

As shown in FIG. 5, the carbon fibers may be mixed in a suitably knitted state such as a net shape or a lattice shape, with the spacing between the fibers being 151 IB or less. In the case of FIG. 5, there is not much contact between the carbon fibers, which improves the antistatic effect and improves the strength of the base.

Further, as shown in FIG. 6, the carbon fibers can be cut into shorter pieces and mixed, and sufficient conductivity can be imparted to the substrate depending on the distribution state or the amount of the carbon fibers mixed. For example, a material having a diameter of 1 to 100 μm may be cut into several μm to several pieces and mixed into the heat-resistant resin. Those with longer lengths within this range can be mixed in the form shown in FIG. 3, or may be mixed in a somewhat curved form. Moreover, short ones can be mixed uniformly, albeit randomly, as shown in FIG.

In order to mix the carbon fibers as described above, it is sufficient to mix the carbon fibers into the molding material at the time of casting the base body.

FIG. 7 shows a situation in which small piece-like carbon fibers n are contained in a gathered state on the surface side of the base material. In this case, the surface of the substrate has fine irregularities due to the partial exposure of the carbon fibers, so if the upper transfer layer 21 is formed by spray coating or dipping, it will follow the irregularities. As a result, fine irregularities are also formed on the surface of the transfer layer 210 (ie, the transfer surface). Particularly, the row of recesses existing on this uneven surface is such that when the belt 5 is pressed onto the image carrier 1 in the suppression transfer area A shown in FIG. 1, toner particles are transferred so as to bite into the recesses. layer 21
Since the toner particles are peeled upward, the peelability (ie, transfer efficiency) of the toner particles is improved. Figure 8 is similar to Figures 3 and 4.
When arranging carbon fibers as shown in the figure, an example in which the fibers n are partially exposed on the surface of the base plate is shown as a horizontal cross section in Figure 3, but this also causes unevenness on the surface of the base plate. Following this, fine irregularities U are formed on the transfer surface of the transfer layer 21, thereby increasing the toner transfer efficiency. However, it is considered desirable to use carbon fibers in the form of small pieces as shown in FIG. 7 in that the transfer surface is uniformly uneven and the toner transfer efficiency is higher.

To obtain fiber distribution states as shown in Figures 7 and 8,
For example, when the base plate is manufactured by centrifugal casting, the centrifugal force may be controlled so that the fibers η are partially localized on the surface side of the base plate. Of course, other methods can also be adopted.

Furthermore, different from the above-mentioned sides, the transfer layer 21 can contain carbon fibers n in the same form as the above-mentioned sides.

For example, as shown in FIG. 9, due to the presence of carbon fibers in the transfer layer 21, there is no charge accumulation as described above, and the thermal and mechanical strength is also increased, resulting in high It is possible to prevent charging and improve the durability of the transfer body (especially the transfer layer itself). The content and mixing form of carbon fiber B may be appropriately determined in consideration of the transfer performance and adhesive performance of the transfer layer 21.

In FIG. 10, carbon fiber η
By making the fibers exist on the surface side of the transfer layer 21, the transfer surface is made uneven by the fibers. In this case as well, the fine recesses on the transfer surface can enhance the releasability of toner particles and improve the transfer efficiency.

As shown in FIGS. 9 and 10, in order to contain carbon fibers n in the transfer layer 21, the fibers n
It is preferable to put on the coating layer, spray coat silicone rubber or the like in this state, and solidify the coated layer while entrapping the fibers n. Alternatively, the surface of the substrate may be dipped in a silicone rubber liquid containing fibers N, and the carbon fiber-containing transfer material A may be adhered onto the surface.

In addition, in the transfer method shown in FIG. 1, since the intermediate transfer belt 5, the toner, and the transfer material are heated together, it is possible to lower the heating temperature required for each of them. It is no longer necessary to excessively heat the heat source, and the amount of heat dissipated can be suppressed to a small level, greatly improving the overall heat utilization efficiency. This also makes it possible to significantly reduce the total energy consumption. . Further, it becomes possible to transfer and fix toner images at high speed. In addition, since the intermediate transfer belt 5 is not heated excessively, even if the image carrier 1 is a photoconductive photoreceptor, which has basic characteristics that are sensitive to heat, its good characteristics can be maintained. It is possible to prevent inconveniences such as a part of the material components of the intermediate transfer belt 5 from adhering to the image carrier 1, and also prevent the intermediate transfer belt 5 from being heated to a high temperature. By not being exposed to severe temperature changes, its durability can be maintained for a long period of time, or the heat resistance conditions required for the material of the intermediate transfer belt 5 are eased, and the range of material selection is expanded. Therefore, it is possible to reduce costs. Further, the toner is not heated excessively, and the image smearing or offset phenomenon due to excessive fluidity of the toner does not occur.

In addition, the transfer material is not excessively heated, thermal deformation and wrinkles of the transfer material do not occur, and of course, there is virtually no risk of fire.

FIG. 11 shows an example in which the intermediate transfer body is of a roll type, and parts common to the above-described example are given common reference numerals and explanations are omitted.

In this example, a pressure roll 9 is brought into pressure contact from below with an intermediate transfer roll 5 having an adhesive layer such as silicone rubber as a transfer layer on a metal roll base, but both rolls 5
．． 9 each have built-in heaters 25A and 9A as described above. This method using an intermediate transfer roll has a much simpler structure than the intermediate transfer belt method,
It also has the advantage that the roll temperature can be easily controlled.

In this intermediate transfer roll, carbon fibers are contained in the transfer layer on the front side in a form as shown in FIG. 9 or FIG. 10 (not shown).

As a result, as described above, it is possible to prevent charge from accumulating, particularly on the surface layer (transfer layer) of the roll 5 as an intermediate transfer member, and to improve its thermal and mechanical strength.

In this case, when a metal such as aluminum is used as the base of the roll 5, a static eliminating member such as that shown in FIG. 1 may be brought into contact with the inner peripheral surface of the base. It is also conceivable to construct the roll base with an insulating material (e.g., heat-resistant resin), but in this case, if carbon fiber is contained in the base as described in FIGS. 3 to 8, the above-mentioned The same effects can be obtained.

Although the present invention has been illustrated above, the embodiments described above can be further modified based on the technical idea of the present invention.

For example, the state of carbon fiber content (form, distribution, content) is not limited to what is described above, and can be changed in various ways.

Furthermore, instead of carbon fibers, metal fibers may be mixed as other conductive fibers, or carbon fibers and metal fibers may be used in combination. Furthermore, conductive fibers and non-conductive fibers (for example, glass It is also possible to use it in combination with fibers). The conductive fibers may be contained in both the substrate and the transfer layer of the intermediate transfer body at the same time. Further, although it is common to use copy paper as the next transfer material, it is also conceivable to configure the transfer toner image to be temporarily transferred to a second intermediate transfer belt or roll.

[Brief explanation of the drawing]

The drawings show examples of the present invention, in which Fig. 1 is a schematic diagram of a recording device, Fig. 2 is a sectional view of an intermediate transfer body, and Fig. 3 is an intermediate transfer belt whose base material contains carbon fiber. (however, cross-sectional hatching is omitted; the same applies hereinafter), Figure 4 is a cross-sectional view of the base body in Figure 3, Figure 5 is a cross-sectional view of the base body according to another example, Figures 6 and 7. 8 is a sectional view of an intermediate transfer body according to a modification of FIG. 3, cut in a direction perpendicular to the moving direction of the intermediate transfer body, and FIG. 10 is a sectional view similar to FIG. 8 of another intermediate transfer body in which the transfer layer contains carbon fiber; FIG. 11 is an intermediate transfer body in which the transfer layer contains carbon fiber. 1 is a schematic cross-sectional view of a recording device using a roll-shaped body. In addition, in the symbols shown in the drawings, 1... photosensitive drum (image holding body) 3... developing section 5... intermediate transfer belt 7... O, heating rolls 7A, 9A, 25A--@Heater 9・φ・・Pressure roll 13・・Static neutralization member addition・・Heat-resistant resin film base 21・・Transfer layer (adhesive layer) n・・・Carbon fiber... ... Intermediate transfer member moving direction U ... Concavity or unevenness 5 ... Intermediate transfer roll A ... Pressure transfer area B ... Intermediate transfer member heating area C ... Transfer fixing area D... Transfer material heating area T... Toner image P... Transfer material. Attorney Hiroko Saka 21'VJ 73 41st Yo

Claims (1)

[Scope of Claims] 1. An intermediate transfer body used for transferring a toner image on an image carrier and further transferring this transferred toner image to a next transfer material, which contains conductive fibers. An intermediate transfer body characterized by: 2. The intermediate transfer body according to claim 1, wherein the base body is made of a heat-resistant resin and contains conductive fibers. 3. The intermediate transfer member according to claim 1, wherein the transfer layer on the image carrier side contains conductive fibers. 4. The intermediate transfer member according to any one of claims 1 to 3, wherein conductive fibers are arranged along the moving direction of the intermediate transfer member. 5. The intermediate transfer member according to any one of claims 1 to 4, wherein the conductive fibers are arranged in parallel lines, a net shape, or a lattice shape at intervals of 15 words or less. 6. The intermediate transfer member according to any one of claims 1 to 5, wherein the conductive fiber has a diameter of 1 to 100 μm. 7. The intermediate transfer member according to any one of claims 1 to 6, wherein the conductive fibers have a length of several μm to several words. 8. Conductive fibers are contained in a proportion of a few bundles to several tens of weight percent. , an intermediate transfer member according to claim 6 or 7. 9. The intermediate transfer member according to any one of claims 1 to 8, wherein fine irregularities are formed on the surface of the transfer layer by containing conductive fibers. 10. The intermediate transfer member according to any one of claims 1 to 9, wherein the conductive fibers are carbon fibers or metal fibers. 11. Claims 2 to 10, wherein the belt-shaped heat-resistant resin film substrate is made of polyimide, polyamide, polyamideimide, polyallylsulfone, polyester, arylate resin, or a mixture of two or more thereof.
The intermediate transfer body described in any one of the above items. 12. The intermediate transfer member according to any one of claims 1 to 10, wherein the base body is configured in a roll shape. 13. The intermediate transfer member according to any one of claims 1 to 12, wherein the transfer layer is made of silicone rubber, fluororubber, or fluororesin.