JP2792096B2 - Method of manufacturing endless resin film belt for electrostatic transfer device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an endless resin film belt used in an electrostatic transfer device.

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine, as a method of transferring a toner image formed on an image carrier (represented by a photoreceptor) to a transfer material (represented by paper), paper is used. In general, the toner is electrostatically adsorbed by charging the toner from the rear side while conveying the toner over the toner image. In particular, a transfer method in which a sheet is temporarily supported on a transfer drum that is driven to rotate in synchronization with a photoreceptor and is used for transfer is mainly used in a color copying machine because this enables multiple transfer to a sheet. Is done.

Means for supporting the paper on the transfer drum include those using a mechanical gripping mechanism such as a gripper, and those using electrostatic attraction. Of these, those using electrostatic attraction are used to transfer the paper from an arbitrary position on the transfer drum. Can be supported, so that the paper interval can be narrowed regardless of the size of the paper in the longitudinal direction, and there is an advantage that the copying speed is improved accordingly.

FIG. 3 is a diagram showing a conventional electrostatic transport transfer device which embodies a method of supporting a sheet on a transfer drum by electrostatic attraction. Reference numeral 2 denotes a photoconductor, which sends a toner image T obtained by development by a developing device (not shown) to a transfer position. 4
Is a transfer drum rotatably supported so as to abut or approach the surface of the photoreceptor 2 via a sheet at a transfer position. The transfer drum 4 has a partial side view and a development plane viewed from the inside. As shown in FIGS. 4 and 5, respectively, a resin film belt 6 formed endlessly and a plurality of electrodes 8a and 8b alternately formed at regular intervals inside the resin film belt 6. And a support 10 made of an insulating film for fixing each of these electrodes 8a and 8b to the resin film belt 6. The width of the support 10 is made smaller than the width of the resin film belt 6, whereby the electrodes 8a and 8b are alternately exposed inside the resin film belt 6, and each of the electrodes 8a and 8b is supplied with power from another power supply brush. Can be received. The transfer brushes 12a, 12b and the suction brushes 14a, 1
4b, 16a, 16b are fixed.

FIG. 6 is a power supply connection diagram of each brush. The transfer brushes 12a and 12b that slide on the electrodes 8a and 8b at the transfer position are connected to the positive side of a power supply 18 via a switch 20, and the negative side of the power supply 18 is grounded. The suction brushes 14a and 16a sliding on the electrode 8a at the paper transport position except the transfer position are grounded, and the suction brushes 14b and 16b sliding on the electrode 8b at the paper transport position are also switches 24 and The power supply 22, 26 is connected to the positive side via a power supply 28, and the negative side of the power supply 22, 26 is grounded.

The operation of the electrostatic transfer device having the above configuration will be described. The paper 32 placed on the paper feed tray 30 is sent out at a predetermined timing by the rotation of a feed roller 34 pivotally supported so as to contact the upper surface of the paper 32. When the leading edge of the sheet reaches the vicinity of the transfer drum 4, the switch 24 is turned on, and the power supply 22
Is applied to every other electrode 8b via the electrode 14b, and the electric field generated between the electrodes 8a and 8b causes the paper and the resin film belt 6 to be charged to different polarities and exerts an attractive force on each other. Become. Thus, when the paper supported on the surface of the transfer drum 4 approaches the transfer area in synchronization with the rotation of the transfer drum 4, the switch 20 is turned on, and a DC voltage is applied to both the electrodes 8a and 8b, and the paper is The transfer is executed by electrostatically attracting the toner image T on the photoreceptor 2 which is charged to the opposite polarity to the image T and rotates at the same peripheral speed as the paper. At this time, transfer brush
DC voltage is applied to the suction brushes 14b and 16b located downstream of 12b, and when this transfer is full-color copying, the paper that has finished transferring the first color is continuously applied to the transfer drum. I have come to support it. Second color, third
The transfer by color is performed in the same manner, and when the transfer for three or four times is completed, the switch 28 is turned off, and the sheet is separated from the transfer drum 4 by the separation claw 36 and sent out onto the transport belt 38. In the case of monochrome copying, switch 28
Is always turned off, and the sheet is discharged each time one transfer is completed.

However, with the above configuration, during paper transport,
Since the plurality of electrodes 8a and 8b are always at the same potential and the paper or semiconductive resin film belt 6 being transported is partially charged, the electrodes 8a and 8b are used when performing the transfer at the transfer position. At high pitches, high and low density portions alternately occur. In order to avoid this phenomenon (hereinafter referred to as an electrode pattern), a configuration as shown in FIG. 7 has been proposed.

In this conventional example (FIG. 7), instead of each electrode in the laminated structure of FIG. 5, an electrode 7 configured to be exposed inside the resin film belt 6 at both ends is formed.
The power supply brushes 9a and 9b are alternately slid on the exposed portions on both sides. Brush 9a is grounded and brush 9b
Assuming that a voltage is applied to each of the electrodes 7, the application of an electric field and the connection to the ground portion are alternately repeated according to the rotation of the resin film belt 6.
Each electrode does not always have the same potential, preventing charge from being accumulated on the resin film or paper, and eliminating the electrode pattern.

On the other hand, as a method for manufacturing a resin film belt, the following method has conventionally been generally practiced. That is, an endless resin film is formed by forming a plurality of electrodes at regular intervals on one side of the resin film by screen printing using a silver paste and connecting the ends of the resin film with the electrode forming surface inside. I was getting a belt. The resin film belt thus obtained is directly supported by a pair of rollers without being supported by the support drum, in addition to the case where the transfer belt is supported on the support drum as in the conventional example described above. It may be used by winding.

Problems to be Solved by the Invention As a method of connecting the end portions of the resin film to form the resin film belt into an endless shape, a method by adhesion and a method by thermocompression bonding have been implemented or proposed. The connecting part is required to have the following.

(B) Electrical characteristics such as volume resistivity (ρ) and dielectric constant (ε) at the connecting portion are equivalent to those of the portion other than the connecting portion. This is because if the electrical characteristics of the connecting portion are unique, it is impossible to uniformly transport and transfer the paper in the circumferential direction of the resin film belt.

(B) The electrode shall not be damaged at or near the joint. This is because, if the electrode is damaged, not only is it impossible to apply an electric field satisfactorily, but also a spark is generated when power is supplied to that portion, and the resin film may burn.

(C) There should be no steps at the connection. If there is a step,
This is because when the stepped portion collides with the photoconductor, the photoconductor or the like vibrates due to the impact, and the written image may be disturbed.

Conventionally, the method by thermocompression bonding is (a) and (c)
Can be satisfied, but when the resin film is heated, wrinkles may be generated in the vicinity of the connecting portion and the electrode may be peeled off, so that the requirement (b) cannot be satisfied. On the other hand, in the case of the method by adhesion, the requirement of (b) can be satisfied, but since the adhesive fixed to the connecting portion is interposed and the electrical characteristics are generally different from those of the resin film, the requirement of (a) is satisfied. I could not be satisfied. Further, since it is necessary to provide an adhesive margin, the requirement (c) is not satisfied.

The present invention has been created in view of such circumstances,
It is an object of the present invention to provide a method of manufacturing an endless resin film belt that can simultaneously satisfy the above requirements (a), (b), and (c).

Means for Solving the Problems The technical problem described above is that a plurality of electrodes are formed at regular intervals on one surface of a semiconductive strip resin film made of a thermoplastic resin, and the electrodes are formed inside the strip resin film. The problem is solved by the method of the present invention in which the opposing edges are overlapped and the upper edges are thermocompression bonded while cooling the periphery.

Action In the method of the present invention, the reason why the belt-shaped resin film is formed from a thermoplastic resin is to enable thermocompression bonding between edges of the belt-shaped resin film. That is, in the case of a strip-shaped resin film made of a thermoplastic resin, a connection portion having sufficient mechanical strength can be formed by applying heat and pressure to the overlapped portion. According to the thermocompression bonding, the electrical characteristics of the connecting portion do not differ from the electrical characteristics of the portion other than the connecting portion. Incidentally, in order to improve the mechanical strength of the connecting portion, it is free to use the adhesive in such an amount that does not change the electrical characteristics.

Further, in the method of the present invention, the periphery thereof is cooled at the time of thermocompression bonding in order to prevent wrinkles from being generated at the peripheral portion due to the thermal influence of thermocompression bonding.

As described above, according to the present invention, it is possible to simultaneously satisfy the requirements (a), (b), and (c).

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a view for explaining a process of forming an electrode on a resin film. First, as shown in FIG. 2A, an electrode 42 is fixed on the surface of a semiconductive resin film 40. A plurality is formed at intervals. The semiconductive resin film 40 is made semiconductive by adding an appropriate amount of an antistatic agent such as carbon black to a thermoplastic resin such as acrylic, polyvinyl chloride, polyester, or polypropylene. Examples of the method of forming the electrode 42 include a method of forming an electrode mainly composed of silver or the like by screen printing and a method of forming a copper electrode by etching and forming a nickel film thereon to prevent abrasion. Can be used.

Next, as shown in FIG. 2B, the resin film 40 on which the electrodes 42 are formed is interposed between the heating presses 44, 44, and the resin film 40 is formed.
Is heated to a temperature at which it can be plastically deformed, and the resin film 40 is pressed from both sides. By doing so, the electrode 42 that hardly undergoes plastic deformation is buried in the resin film 40, and the electrode 42 having the surface on the same plane as the surface of the resin film 40 as shown in FIG. 'Is formed. The reason why the electrodes are buried in the resin film is to prevent the electrodes from being worn by brushing when brush power is supplied.

FIG. 1 is a process chart in the case of forming an endless resin film belt in which electrodes are buried as described above. First,
As shown in FIG. 7A, the opposing edges are overlapped with the electrode 42 'forming surface of the resin film belt facing inward.
The overlapped portion is thermocompression-bonded by heating presses 46,46. Reference numerals 48 and 50 denote coolers through which a coolant such as water flows, which cools the vicinity of the thermocompression bonding portion during thermocompression bonding to prevent wrinkles in the resin film 40. In this way, since the vicinity thereof is cooled during the thermocompression bonding, the vicinity thereof is prevented from being plastically deformed due to the heat transfer from the thermocompression bonding portion to cause wrinkles, and the electrode 42 'is not likely to peel. Also, since the thermocompression bonding is performed, the connecting portion is plastically deformed and no step is generated as shown in FIG. If there is a step due to some inconvenience, it may be cut. Therefore, when the endless resin film belt is supported on the support drum 54 as shown in FIG.
It can be made substantially equal to the thickness t ₂ at t ₁ and the portion other than the bonding portion.

As described above, according to the present embodiment, the thickness of the endless resin film belt can be made uniform in the circumferential direction. The sheet can be sucked from any position regardless of the position, and the processing speed is improved. Also, since there is no step in the thermocompression bonding portion, there is no possibility that the photosensitive drum will vibrate when the transfer drum and the photosensitive drum are in contact with each other, and image disturbance is prevented especially in a digital copying machine. .

Effects of the Invention As described in detail above, according to the present invention, (a)
There is an effect that it is possible to provide a method of manufacturing an endless resin film belt for an electrostatic transfer device which can simultaneously satisfy the requirements (b) and (c).

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, in which a resin film belt is formed endlessly. FIG. 2 is a view showing an embodiment of the present invention, in which an electrode is formed on a resin film. FIGS. 3 to 7 are views for explaining the prior art. 40 ... Resin film, 42,42 '... Electrode, 44,46 ... Heating press, 48,50 ... Cooler.

Continuation of front page (72) Inventor Tatsuo Okuno 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Ebina Works (56) References JP-A-61-232477 (JP, A) (58) .Cl. ⁶ , DB name) G03G 15/16 B29D 29/00 B65H 5/00

Claims (1)

(57) [Claims] 1. A plurality of electrodes are formed at regular intervals on one surface of a semiconductive strip resin film made of a thermoplastic resin, and opposing edges of the strip resin film are overlapped with the electrodes inside. A method for producing an endless resin film belt for an electrostatic transfer device, wherein said edges are thermocompression bonded to each other while cooling the periphery thereof.