JPS62156682A - Transfer belt - Google Patents

Abstract

PURPOSE:To eliminate joints and steps and to prevent the remaining of a toner by integrally coupling an inside conductor layer and outside dielectric layer formed respectively of specific materials respectively having specific volume resistivities to an endless annular shape. CONSTITUTION:A transfer belt 2 is constituted of the inside conductor layer 3 consisting of a thermoplastic elastomer or ionomer contg. conductive fillers and the outside dielectric layer 4 consisting of a thermoplastic resin and both layers are integrally coupled to the endless annular shape. The volume resistivity of the conductor layer 3 is preferably <=10<6>OMEGAcm and the volume resistivity of the dielectric layer 4>=10<14>OMEGAcm. The generation of defective cleaning by remaining of the toner during cleaning is thus obviated and the image quality of transfer is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a transfer bell 1- used in an image forming apparatus such as a ppc (plain paper copying machine).

BACKGROUND TECHNOLOGY In general, transfer belts used in RPC (plain paper copying R) carry out the functions of transporting paper, transferring images onto paper, and separating the transferred paper. , a conductive sheet made of EPDM or polyurethane rubber containing a conductive filler such as carbon black and having a volume resistivity of 106 Ω·cm or less on the inside, and a dielectric material having an insulating property with a volume resistivity of 1014 Ω·cm or more. It was manufactured by bonding the two together with the film on the outside, and then seaming both ends of the composite sheet of the required length to form an endless sheet. However, in such a conventional transfer belt, there is a step at the seam of the composite sheet, and when the transfer belt is cleaned with a cleaning blade, toner remains on the step, resulting in poor cleaning. Furthermore, if the joints of the transfer belt are not sufficiently bonded, the transfer belt may break, necessitating the interruption of use of the copying machine.

Therefore, conventionally, endless belt base materials were made from EPDM containing conductive filler, polyurethane rubber, etc.
The outer surface of this belt base material is coated with a resin solution prepared by dissolving a synthetic resin such as polyester resin in a solvent with a volume resistivity of 1 o 16 Ω cm or more by spraying, or by a tube coating method. A method of forming a dielectric layer of 50 μm was implemented, but this resulted in air bubbles and pinholes forming on the surface of the resin film during spraying or coating, deteriorating the quality of the transfer belt, and also causing the formation of a dielectric layer by spraying or coating. Since the thickness of the resin film of the dielectric layer is thin, the resin film on the surface of the transfer belt is abraded when the transfer belt is used, and the life of the transfer belt is extremely short. Furthermore, since the synthetic resin is applied to a solvent and sprayed or coated, there is a problem that the resins that can be used are limited. Furthermore, according to this conventional method, the belt base material must be uniformly sprayed or coated with a resin solution, which requires skill, making the production of the transfer belt extremely troublesome and time-consuming, and increases production costs. In addition to being expensive,
There was a problem that the quality was inconsistent and the price was low.

OBJECT OF THE INVENTION The purpose of the present invention is to solve the above-mentioned problems, and is an endless ring without any seams or steps unlike conventional ones, so that toner remains during cleaning, resulting in poor cleaning, or breaks during use. In addition, the dielectric layer is sufficiently thick - it has excellent abrasion resistance and durability, and there are no pinholes or bubbles on the surface, and the dimensions are small. To provide a transfer belt that has excellent accuracy, has good charge characteristics and retention rate, can transfer an image from a photoreceptor drum very well, is easy to manufacture, and is inexpensive to manufacture. It is in.

Structure of the Invention In order to achieve the above object, the present invention is composed of an inner conductive layer made of a thermoplastic elastomer or ionomer containing a conductive filler, and an outer dielectric layer made of a thermoplastic resin. The gist is a transfer belt in which both layers are integrally connected in an endless ring shape.

In the above, the volume resistivity of the conductor layer is 106Ω・cm
The volume resistivity of the dielectric layer is 1014Ω・cm
That's all. In addition, the thickness of the conductor layer is approximately 0.1 to 2 mm,
and the thickness of the dielectric layer is 20 to 200 μm, and the thickness is 40 to 1
Preferably it is 100u. The inner diameter of the conductor layer is, for example, 100 to 150 mm.

The conductor layer is made of thermoplastic elastomer or ionomer as a base material, and about 20 to 30% by weight of conductive filler is mixed therein, and the dielectric layer is made of thermoplastic resin.

The thermoplastic elastomer used as the base material of the conductor layer is
Polyurethane thermoplastic elastomer, polyester thermoplastic elastomer, polystyrene thermoplastic elastomer, polyolefin thermoplastic elastomer, φ+
At least one thermoplastic selected from the group consisting of 1.2-polybutadiene-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, fluorine-based thermoplastic elastomer, and polyvinyl chloride-based thermoplastic elastomer. It is an elastomer.

In addition to these, ionomers can be used as the base material of the conductor layer.

Polyurethane thermoplastic elastomers are basically composed of polyols and polyisocyanates.
As the polyol, for example, polyester polyol or polyether polyol is used. A caprolactam-based thermoplastic elastomer may also be used.

Further, the conductive filler mixed into the thermoplastic elastomer may be at least one selected from the group consisting of carbon black, metal powder, carbon fiber, and metal fiber.
It consists of two conductive substances.

Furthermore, the thermoplastic resin constituting the dielectric layer is selected from polyethylene terephthalate, ionomer, polybutylene terephthalate, polyvinyl chloride, olefinic thermoplastic elastomer, polypropylene, polyethylene, fluororesin, polyacetal resin, polycarbonate, ABS resin, and polyester resin. At least one resin selected from the group consisting of: Among these, polyethylene terephthalate and ionomer are preferably used from the viewpoint of processability.

Further, an appropriate adhesive layer is used depending on the type of thermoplastic elastomer that constitutes the base material of the conductor layer and the thermoplastic resin that constitutes the dielectric layer.

The transfer belt according to the invention is produced by simultaneously and integrally molding the inner conductor layer, the outer dielectric layer, and optionally the intermediate adhesive layer, for example by extrusion blow molding.

That is, a two-layer or three-layer spiral mandrel die (when an intermediate adhesive layer is provided) is set, and the inner layer material is applied to this die using an extruder having a diameter of 32 mm.
The outer layer material is extruded at the same time using an extruder of m, thereby obtaining a tubular molded product in which the conductor layer and the outer dielectric layer are integrated.An air ring is provided at the die exit to keep the shape constant, and then It is cooled to solidify the resin in both layers, and then cut to a certain size.

Example Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a PPC using the transfer belt according to the present invention.
<Plain paper copying machine).

In the figure, (1) is a photoreceptor drum, (2) is a transfer belt of the present invention arranged horizontally below the photoreceptor drum (1), and this is a pair of front and rear rotary drive rollers (506
) and rotated in synchronization with the photoreceptor drum (1). (7) (7) is a paper timing roll placed near the starting end of the transfer belt (2); (8)
is the transfer charger, and (9) is the I? of the transfer belt (2). 'S
This is a cleaning blade placed on the lower side.

The transfer belt (2) has an inner conductive layer (3) made of a polyurethane thermoplastic elastomer containing 20% by weight of carbon black as a conductive filler, and an outer dielectric layer (4) made of an ionomer. They are integrally connected in an endless ring shape. The inner diameter of the transfer belt (2) is 1
The length is 1511 m and the width is 320 ml. here,
The properties of the conductor layer (3) and dielectric layer (4) are as follows.

Conductor layer (3) Z.

Hardness J l5A) 8tD7L breaking strength
450 K (1/cm2 elongation at break
500% tear strength 90KO/cm volume resistivity
1 x 106Ω・cm thickness 40
0μm Inner diameter 115mm Dielectric layer (4) Hardness Shore D) 50~65L Breaking strength 300g/cm2 Breaking elongation
500% Dielectric constant 2~3 Volume resistivity 1 x 1018Ω・cm thickness
50/, (II The above transfer belt of the present invention (2
) and conventional products, we tested their charging characteristics.

In other words, the applied pressure is 7.5KV! l: L, normal temperature (2
As a result of measuring the charging state immediately after humidification at 42% RH and 100% RH, the product of the present invention had a humidity of 42% RH.
+1500 for both RH and 100%RH
The conventional product generated a charge of +1500V at humidity of 42%RH, but could only obtain a charge of +900V at humidity of 100%RH, and the retention rate was also very good. The rate was very poor.

Furthermore, when the surface conditions of the transfer belt of the present invention and the conventional product were measured, the product of the present invention had no pinholes and bubbles, whereas the conventional product had many pinholes and bubbles on its surface. The results of measuring the surface roughness of the inventive product and the conventional product are as follows:
It is as follows.

Surface roughness: Inventive product: 1 to 1.5 μm Conventional product: Spray coating: 3 to 5 μm Tube containing: 1.5 to 3 μm When copying was performed using the transfer belt of the above example, the image was transferred from the photoreceptor drum (1). It was able to transfer extremely well, form clear images on paper, and was extremely durable compared to conventional products.

Effects of the Invention As described above, the transfer belt of the present invention is composed of an inner conductive layer made of a thermoplastic elastomer or an ionomer containing a conductive filler, and an outer dielectric layer made of a thermoplastic resin. Since the layers are joined together in an endless ring, there are no seams or steps like in the past, and therefore toner may remain during cleaning, resulting in poor cleaning, or may break during use. In addition, the dielectric layer has sufficient thickness to provide excellent wear resistance and durability, and there are no pinholes or bubbles on the surface, ensuring dimensional accuracy. It has excellent charge characteristics and retention rate, and can transfer an image from a photoreceptor drum very well. Moreover, it is easy to manufacture and has the effect of reducing manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of an RPC (plain paper copy 11) using the transfer belt of the present invention, and FIG. 2 is a partially enlarged cross-sectional view of the product of the present invention. (1) Photoreceptor drum, ( 2)...transfer belt,
(3)...Conductor layer, (4)...Dielectric layer. In addition to the above, 4 other people attended the formalities, 4th June 1985, Z.D. Filiance Officer, Black 1) Mr. Myoso.
21. Indication of the case Showa 60 Foreign Special; 'I Application No. 297370g2, R'l'l'7) R8
H'T'''''jK'il-43, Relationship with the person making the amendment/I'if'l Patent applicant (1 place)
Hirakata City +01j, i Tachika 2-7 Name
Yamauchi Gomuni [Gyo Co., Ltd. Uchi 4, Agent [1] 5-22-3 Higashigotanda, Tokyo Parts Ward
Contents of amendment No. 3: “Coating” on page 5, lines 9, 12, and 14 of the specification has been changed to “
"Capsule", respectively. , on page 8, line 14 of the same book, "polyester" is corrected to "polyester". , ``1 polyester'' in the last line of 8 in the same book is divided by i'ill. , p. 10, line 15 to p. 11, line 2 of the same book, "Adhesive is also used." has been revised as follows. [An adhesive layer may be interposed between the conductive layer and the dielectric layer depending on the case. Here, as the adhesive layer, an appropriate one is used depending on the type of thermoplastic elastomer or ionomer constituting the base material of the conductor layer and the thermoplastic elastomer or ionomer constituting the dielectric layer. In addition, in order to reinforce the entire transfer belt, at the boundary between the conductive layer and the dielectric layer, especially on the conductive layer side, polyamide paper 1 [and organic fibers such as polyester fiber, or inorganic fibers such as glass fiber and asbestos] Fibers, yarns, woven fabrics, etc. made of these fibers may be buried. ” 5. In the same book, page 12, line 10, “supply paper” is corrected to “paper feed.” 6. Correct "82" in line 8 on page 13 of the same book to "82°". Correct "65 degrees" on the last line of the same page to "65 degrees."that's all

Claims (3)

[Claims] (1) Transfer consisting of an inner conductive layer made of a thermoplastic elastomer or ionomer containing a conductive filler and an outer dielectric layer made of a thermoplastic resin, both layers being integrally bonded in an endless ring shape. belt. (2) The thermoplastic elastomer is a polyurethane thermoplastic elastomer, a polyester thermoplastic elastomer, a polystyrene thermoplastic elastomer, a polyolefin thermoplastic elastomer, a 1,2-polybutadiene thermoplastic elastomer, a polyamide thermoplastic elastomer, or a fluorine-based thermoplastic elastomer At least one thermoplastic elastomer selected from the group consisting of a thermoplastic elastomer and a polyvinyl chloride thermoplastic elastomer, and the conductive filler is selected from the group consisting of carbon black, metal powder, carbon fiber, and metal fiber. The thermoplastic resin is made of at least one conductive substance selected from polyethylene terephthalate, ionomer, polybutylene terephthalate, polyvinyl chloride, olefinic thermoplastic elastomer, polypropylene, polyethylene, fluororesin, polyacetal resin, The transfer belt according to claim 1, wherein the transfer belt is at least one resin selected from the group consisting of polycarbonate, ABS resin, and polyester resin. (3) The transfer belt according to claim 1, wherein the conductive layer has a volume resistivity of 10^6 Ω·cm or less, and the dielectric layer has a volume resistivity of 10^1^4 Ω·cm or more.