JP2003118002A - Method for connecting plastic film, endless belt-like electrophotographic photosensitive member to be manufactured by the method, and electrophotographic apparatus having the photosensitive member mounted thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for connecting a plastic film which improves a connecting strength without increasing the thickness of a connecting part by superposing and connecting both ends of a plastic sheet or sheet-like electrophotographic photosensitive member to an endless belt-like state. SOLUTION: The method for connecting the plastic film comprises the steps of superposing both edges of the plastic film, moving an oscillating ultrasonic fusion bonding horn along the superposed part by pressing the horn against the superposed part, and connecting the superposed part in such a manner that when the film is superposed before connecting, an interval between the distal end of the upper film and the surface of the lower film is 35 μm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining method for forming a plastic film into an endless belt shape, and an electrophotographic photosensitive member manufactured by using this joining method.

[0002]

2. Description of the Related Art Conventionally, electrophotographic photoconductors have been widely used not only in copying machines but also in printers connected to facsimiles and personal computers. In recent years, the speeding up or colorization has been remarkably progressing. In addition, development of on-demand printing using electrophotographic technology is also in progress.

The electrophotographic photosensitive member has a belt shape and a drum shape. The belt-shaped electrophotographic photosensitive member is a method in which a sheet-shaped electrophotographic photosensitive member is prepared and joined or bonded to form a belt. There is a method of forming an electrophotographic photoreceptor layer on a seamless belt, but in most cases, the former method is adopted. The sheet-shaped electrophotographic photosensitive member is one in which a photosensitive layer is formed on a conductive substrate in which a conductive layer (aluminum vapor deposition layer or the like) is provided on a film-shaped support (polyester film or the like). As for the endless belt-shaped electrophotographic photosensitive member, a method of joining the above-mentioned sheet-shaped electrophotographic photosensitive members by ultrasonic fusion to form an endless belt-shaped member has been widely put into practical use. (Patent Fair 6-543
No. 93)

By the way, when the endless belt-shaped electrophotographic photosensitive member is used in the above-described high speed apparatus or on-demand printing apparatus, high durability is required for the belt, and the conventional ultrasonic bonding method is used. Then
In some cases, the bonding strength was insufficient. That is, the belt may be conveyed at a speed of 280 mm / sec or more due to the increase in speed, or the number of rolls in contact with the inner and outer surfaces of the belt may be three or more due to colorization of the image. When the belt is used in such a state, a great stress is applied to the belt, which causes a problem of breaking the joint.

To avoid such troubles, it is necessary to improve the bonding strength, but in many cases, the bonding strength is required to be 98 N / cm (about 10 kgf / cm) or more. Further, there are cases where a plurality of four or more transport rolls are used for colorizing an image, and at this time, there is a case of a belt transport layout in which a part of the transport rolls contacts the surface of the photoconductor, but in such a case, Not only is the joint strength simply high in tensile strength, but also high in the direction of peeling the joint. The tensile strength is measured by cutting the joined sample into a width of 10 mm and applying this to a tensile tester.

As a result of earnest studies by the present inventor, when the belt is used in a high speed device or an on-demand printing device, the bonding strength is 127 N / c.
It was found that m (13 kgf / cm) or more was required, and the rupture state of the sample at the time of measuring the tensile strength was that the film was ruptured in a form in which a non-recoverable elongation occurred and the bonded portion was torn. Further, if the joining is insufficient or the joining strength is low, abnormal noise can be heard during joining.

Many methods have been studied in the past as a method for increasing the bonding strength, and some of them are as follows.

(A) Japanese Patent Laid-Open No. 2000-267320: In the invention of the endless belt-shaped electrophotographic photosensitive member described here, a protective layer made of resin is formed at the joint portion. It is necessary to apply a solution in which is dissolved in a solvent and dry it. Also, since the thickness of the joint increases with this method,
In the electrophotographic apparatus, there is a problem that the driving load changes when the joint passes through a belt-wound roll. Further, since the thickness of the joint portion is increased due to the protective layer, there is a problem that it becomes an obstacle to cleaning by the cleaning blade or the cleaning brush. Therefore, with this method, it is possible to improve the bonding strength by increasing the thickness of the protective layer, but there are many side effects due to the increased thickness of the protective layer, and the effect is not perfect.

(B) Japanese Patent Application Laid-Open No. 2000-275883: In the invention of the image forming apparatus and the image forming method and the belt-shaped photosensitive member used therefor described in the invention, a protective layer is formed at the joint to improve the strength. However, similar to (a) above, there are many side effects. Therefore, the method using these protective layers is not sufficient to improve the bonding strength. As a method of forming a protective layer other than a method of forming a protective layer by coating the joint portion, a method of sticking an adhesive tape or a heat seal tape on the joint portion and using this as a protective layer is conceivable. In the method, the work of attaching the tape is troublesome, and the side effect of increasing the thickness of the joint portion due to the tape is the same as in the above (a).

(C) Japanese Patent Laid-Open No. 03-001146: In the invention of the method for producing an endless belt-shaped electrophotographic photosensitive member described here, the shape of the tip of the ultrasonic fusing horn is devised, Bonding strength (bonding force)
Is 8-9 kgf / cm, and it cannot be said that this strength is sufficient.

(D) In addition, many other methods for improving the bonding strength have been studied, for example, Japanese Patent Laid-Open No. 1-28.
In 8860, it is proposed to bond by ultrasonic fusing, and the shape after bonding should be such that the protrusion amount from the bonded part is 1.2 mm or less and the step difference of the bonded part is 100 μm or less. No. 61-185753, a method of forming a protective film containing a solid lubricant on the joint (joint), and in JP-A No. 62-99779, between the photosensitive layer and the support at both ends of the belt before joining. A method of subjecting a synthetic resin support surface to corona discharge treatment in JP-A-5-40355, and a method of performing post-treatment for correcting the shape after bonding in JP-A-8-30001, Further, JP-A-10-111579 proposes a method of forming a specific resin at the joint. However, there are problems in that processing is complicated, or the thickness of the joint portion increases.

The endless belt used in the electrophotographic apparatus is not limited to the electrophotographic photosensitive member, but is also used as, for example, a transfer belt or a conveyor belt.

[0013]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to form a belt-shaped electrophotographic photosensitive member when joining plastic sheets to form an endless belt, or to join a sheet-shaped electrophotographic photosensitive member. In doing so, it proposes a method for improving the bonding strength simply and without increasing the thickness of the bonded portion.

[0014]

In order to achieve the above-mentioned object, the present inventor has made many studies on a method of bonding a plastic film and a method of obtaining a bonding strength of 127 N / cm (13 kgf / cm) or more. The inventors have found that it is necessary to make the distance between the surfaces of the upper film tip and the lower film when superposed on each other be 35 μm at the maximum, and have completed the present invention.

Therefore, the above problems are as follows (1) to (13)
Achieved by

(1) The both ends of the plastic film are overlapped with each other, and the oscillating ultrasonic fusing horn is pressed against the overlapped part and moved along the overlapped part to move the overlapped part. In the joining method, when the plastic films are superposed before joining, the distance between the upper film tip and the lower film surface is 35
A method for joining plastic films, characterized in that the thickness is not more than μm.

(2) In the joining method described in (1) above, the thickness of the plastic film is 70 μm or more and 25
A method for joining plastic films, which is 0 μm or less, and the overlapping width of the plastic films before joining is 0.3 mm or more and 1.5 mm or less.

(3) In the joining method described in (1) or (2) above, the temperature difference between the horn tips at the joining start point and the joining end point is 10 ° C. or less.

(4) In the joining method described in (1), (2) or (3) above, the plastic film is fixed to the joining table by vacuum suction or electrostatic attraction during ultrasonic joining. How to join plastic films.

(5) In the joining method according to any one of the above (1) to (4), the thickness of the joining fusion-bonded portion after joining is
A method for joining plastic films, wherein the thickness is not less than 1 time and not more than 1.6 times the thickness of a portion that is not a fusion-bonded portion.

(6) In the joining method according to any one of (1) to (5) above, the plastic film immediately before passing through the ultrasonic welding horn is mechanically held down, and the plastic films are superposed before joining. A method of joining plastic films, characterized in that the distance between the tip of the upper film and the surface of the lower film is 35 μm or less.

(7) In the joining method described in (6) above, the position where the plastic film is mechanically held is 0.5 mm or more and 10 mm or less before the horn in the traveling direction of the ultrasonic fusing horn. Method for joining plastic films.

(8) In the joining method according to (6) or (7), the pressure for holding the overlapped portions of the plastic films is 25 kPa or more and 125 kPa or less, which is a plastic film joining method.

(9) In the joining method according to any one of (1) to (5) above, when a step is provided on the table on which the plastic film is placed and the plastic films are superposed before joining, the upper end of the film is A method for joining plastic films, characterized in that the distance between the lower film surfaces is 35 μm or less.

(10) In the joining method described in (9) above, the height of the step provided on the table on which the plastic film is placed is 0.2 times or more the thickness of the plastic film, and 1.4.
A method for joining plastic films, which is less than double.

(11) In the joining method according to any one of (1) to (5) above, when the plastic films are superposed before the joining, the sheet is placed on the whole end surface or the upper end with an inclination, and the sheets are superposed. A method for joining plastic films, wherein the distance between the top of the upper film and the surface of the lower film when combined is 35 μm or less.

(12) An endless belt-shaped electrophotographic photosensitive member manufactured by being bonded by the bonding method according to any one of (1) to (11) above.

(13) An electrophotographic apparatus comprising the endless belt-shaped electrophotographic photosensitive member described in (12) above.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. As described above, in the present invention, when the plastic films are superposed before joining, it is necessary that the distance between the upper film tip and the lower film surface is 35 μm or less. This means that the higher the adhesiveness of the upper plastic film and the lower plastic film immediately before passing through the ultrasonic fusing horn, the greater the bonding strength can be obtained.

This has the effect of preventing the melted substance exuded by the static pressure applied to the horn when passing through the ultrasonic fusing horn from entering the gap portion in the horn advancing direction. That is, by increasing the amount of the extruded portion extruded in a direction substantially perpendicular to the traveling direction of the horn, the joining force of the other plastic film surface superposed on the end face of the plastic film can be strengthened. On the contrary, if there is a re-solidified substance that has exuded in the horn traveling direction, the horn momentarily rides on this and the bonding force is reduced, or a non-bonded portion is generated and stable bonding becomes difficult.

Further, since the adhesion between the plastic films is increased, the ultrasonic energy is efficiently propagated and the energy used for bonding is increased.
A bonding strength of 3 kgf / cm or more can be stably obtained. The abnormal noise generated when the joining is insufficient is presumed to be due to some action of energy not used for joining.

Further, in the example shown here, the superposed plastic films are fixed and the ultrasonic bonding horn is moved, but this is the case where the ultrasonic bonding horn is fixed and the superposed electrophotographic photosensitive member is moved. They may be moved, or both may be moved.

As the ultrasonic welding horn used here, a horn generally used for welding plastics can be used, and the material thereof is duralumin,
Aluminum, monel, phosphor bronze, titanium, etc. can be used. Further, different materials can be used for the tip portion of the horn for the purpose of improving wear resistance. For example, the main body may be made of Monel and only the tip may be made of super steel.

The thickness of the plastic film is preferably 70 μm or more and 250 μm or less, more preferably 75 μm.
It is not less than μm and not more than 150 μm. Further, the overlapping width of the plastic films before joining is preferably 0.3 mm or more and 1.5 mm or less, more preferably 0.
It is from 5 mm to 0.8 mm. This enables ultrasonic bonding with higher strength.

The temperature difference at the tip of the ultrasonic fusing horn before and after joining is preferably 10 ° C. or less, more preferably 5 ° C. or less. By preventing the influence of the temperature change at the tip of the horn during the joining, ultrasonic joining with higher strength becomes possible.

In the method for joining plastic films according to the present invention, by further fixing the plastic film on the entire surface to the joining table, it becomes possible to prevent the displacement of the plastic film when passing through the horn, and therefore a strong and stable joining strength. It becomes possible to perform ultrasonic bonding having As a means for fixing this plastic film to the joining table, it is desirable to use vacuum suction force or electrostatic suction force, but if the condition that the plastic film is completely fixed at the time of joining is satisfied, fixing with adhesive tape , It may be fixed by a weight.

The thickness of the fusion-bonded portion of the plastic film is preferably 1 time or more and 1.6 times or less the thickness of the portion which is not the fusion-bonded portion, and more preferably the thickness of the portion which is not the fusion-bonded portion. It is preferably 1.2 times or more and 1.5 times or less.
As a result, the fusion by ultrasonic waves is completely performed, and the fusion-bonded portion of the plastic film has a strong joint strength.

In the method of joining plastic films of the present invention, it is desirable to mechanically apply pressure when the plastic films are superposed before joining to improve the adhesiveness, which enables ultrasonic joining with high strength. become. Specifically, it is necessary to mechanically hold the plastic film immediately before passing through the horn, but as a holding method, a weight, a spatula, or a finger can be used, and the material includes metal, plastic, and the like. It is preferable that the plastic film is not scratched by applying force.

In the method for joining plastic films of the present invention, it is preferable to avoid contact with the ultrasonic fusing horn and maintain the adhesion between the plastic films when passing through the ultrasonic fusing horn. To this end, the mechanical position (position to which a physical action is applied) is 0.5 mm or more, 1
0 mm or less, preferably 0.5 mm or more, 5 mm
It is the following. This enables ultrasonic bonding with higher strength.

The pressure for holding the plastic film is preferably 25 kPa or more and 125 kPa or less, more preferably 35 kPa or more and 75 kPa or less. As a result, the fixed plastic film can be prevented from shifting and the adhesion between the plastic films can be maintained when passing through the ultrasonic fusing horn, so that ultrasonic bonding with higher strength becomes possible.

At the time of joining, it is desirable to provide a step on the table on which the plastic film is placed, and this step does not have to be perpendicular to the surface of the table and may be inclined. By forming a step on the joining table, the plastic films can be stacked almost in parallel, and ultrasonic bonding with higher strength becomes possible. If the step is higher than the thickness of the plastic film, the distance between the upper film tip and the lower film surface can be 35 μm or less when the plastic films are superposed. The gap with the bottom surface of the film becomes too large and the bonding strength may decrease, which is not preferable.

In the present invention, the cut surface of the plastic film is inclined at the same time as the cutting, but the cut surface may be cut after the cutting so that the cut surface is inclined. The slope does not have to be smooth, and may be roughened by grinding with a file or the like. In this case, when the plastic films are stacked, the corners of the upper surface of the plastic films that are underneath are eliminated, and when the plastic films are stacked, the adhesion between the plastic films is improved, and thus the plastic film may have a stronger bonding strength. it can.

The endless belt-shaped electrophotographic photosensitive member of the present invention can be manufactured by bonding the sheet-shaped electrophotographic photosensitive member in the same manner as in the above-described plastic film bonding method. In this case, the thickness of the sheet-shaped electrophotographic photosensitive member is preferably approximately the same as the thickness of the plastic film. The photosensitive layer of the manufactured endless belt-shaped electrophotographic photosensitive member may have a single layer structure or a laminated structure of a charge generation layer and a charge transport layer. An electrophotographic apparatus is manufactured by mounting at least this endless belt-shaped electrophotographic photosensitive member.

The electrophotographic apparatus of the present invention is equipped with at least the above endless belt-shaped electrophotographic photosensitive member, and if necessary, charging means, exposure means, developing means, transfer means,
The cleaning means is provided.

Next, the endless belt-shaped electrophotographic photoreceptor of the present invention (endless belt-shaped photoreceptor having a photosensitive layer provided on a conductive support) will be described.

As the conductive support used in the present invention,
A plastic film that has been subjected to a conductive treatment is used. For example, metal such as Al, Ag, Au on a plastic film such as polyester, polycarbonate, polyimide,
Alternatively, a thin film of a conductive material such as In ₂ O ₃ or SnO ₂ may be used.

If necessary, an undercoat layer may be provided between the conductive support and the single-layer photosensitive layer adjacent thereto, or the charge transport layer or charge generation layer. In this undercoat layer,
Resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide can be used. Further, a white pigment such as titanium oxide or an anionic conductive polymer such as sulfonic acid or an alkali metal salt of sulfonic acid or ammonium salt may be added.
At this time, it is preferable to select a material that does not dissolve in the solvent used for the forming liquid of the layer laminated on the undercoat layer.

As described above, the photosensitive layer may have a single layer structure or a laminated structure of a charge generation layer and a charge transport layer.

The charge generating layer is composed of a charge generating substance or a charge generating substance and a binder resin. Examples of the charge generating substance include, for example, CI Pigment Blue 25 (Color Index CI 21180), CI Pigment Red 41 (CI 21200), and CI Acid Red 5.
2 (CI 45100), CI basic red 3
(CI 45210), an azo pigment having a carbazole skeleton (described in JP-A-53-95033), and an azo pigment having a distyrylbenzene skeleton (JP-A-53-13).
3445), azo pigments having a triphenylamine skeleton (described in JP-A-53-132347), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-21728), and oxadiene. Azo pigments having an azole skeleton (described in JP-A-54-12742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (JP-A-54). No. 17733), an azo pigment having a distyryloxadiazole skeleton (described in JP-A-54-2129), an azo pigment having a distyrylcarbazole skeleton (JP-A-54-14).
967); phthalocyanine-based pigments such as CI Pigment Blue 16 (CI 74100);
I 73410), CI eye bat die (CI 730)
30) and the like; indigo-based pigments such as Argol Scarlet 5 (manufactured by Bayer), Indurence Scarlet R (manufactured by Bayer), perylene-based pigments, squaric dyes, and hexagonal Se powder.

These charge generating substances are pulverized and dispersed with a solvent such as tetrahydrofuran, cyclohexanone, dioxane or dichloroethane by a method such as a ball mill, an attritor or a sand mill. At this time, for example, polyamide, polyurethane, polyester, epoxy resin,
Resins such as polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide may be added as a binder.

The charge generating layer forming liquid thus prepared is applied and dried by a method such as a bead coating method, a die coating method, a blade coating method or a spraying method to form a charge generating layer. Further, the ratio of the charge generating substance and the binder resin in the charge generating layer is preferably 40% by mass or less of the binder resin of the charge generating substance.

The charge transport layer is composed of a charge transport material or a charge transport material and a binder resin. As the charge transport material,
Anthracene, pyrene, phenanthrene, polycyclic aromatic compounds such as coronene or indole in the main chain or side chain,
Compounds having nitrogen-containing cyclic compounds such as carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, thiadiazole and triazole, triphenylamine compounds, hydrazone compounds (JP-A-55-46760) , Α-Phenylstilbene compounds (JP-A-58-
198043) and the like are used.

Binder resins such as polystyrene, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, styrene-maleic anhydride copolymers, polyesters, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers are used as the charge-transporting substances. Coalesce, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal,
Polyvinyltoluene, poly-N-vinylcarbazole,
A charge transport layer that is dissolved in a solvent such as tetrahydrofuran, cyclolhexanone, dioxane, or dichloroethane together with a thermoplastic or thermosetting resin such as acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, or alkyd resin. A forming liquid is prepared, and the liquid is applied by a method such as a bead coating method, a die coating method, or a spray method, and dried to form a charge transport layer.

Up to now, the photosensitive layer has been described as a laminated type of a charge generating layer and a charge transporting layer, but the photosensitive layer has a single layer, for example, a charge generating substance, a charge transporting substance and a binder resin. It may be a photosensitive layer containing the main component.

[0055]

EXAMPLES Next, the present invention will be described more concretely with reference to Examples and Comparative Examples. Prior to listing these examples and comparative examples, an ultrasonic bonding apparatus and a sheet-shaped electrophotographic photosensitive member suitable for the present invention will be described.

(Ultrasonic Bonding Device) FIG. 1 is a schematic view of an ultrasonic bonding device suitable for the present invention.
Is an ultrasonic oscillator, 3 is an ultrasonic fusing horn made of duralumin whose tip is hard chrome plated, 4 is a weight serving as a pressing force at the time of ultrasonic joining, 5 is a joining table made of steel, and 6 is joining Is a sheet-shaped electrophotographic photosensitive member for carrying out the above, which is placed on a joining table with its edges overlapped. This figure is written to make the overall structure easy to understand,
The scale of each device is not the same.

(Preparation of Electrophotographic Photosensitive Sheet) 1) Conductive Support A plastic film obtained by vapor-depositing aluminum to a thickness of 1000 Å on polyethylene terephthalate having a thickness of 100 μm was used as a support.

2) Formation of Undercoat Layer The following materials were placed in a ball mill and dispersed for 48 hours to prepare a dispersion liquid. Titanium dioxide powder 15 parts by weight Alcohol-soluble nylon resin 3 parts by weight Methyl ethyl ketone 75 parts by weight The resulting dispersion was diluted with 75 parts by weight of methyl ethyl ketone to prepare an undercoat layer coating solution. An undercoat layer coating solution was applied by die coating to a polyethylene terephthalate film on which aluminum was vapor deposited, and dried at 120 ° C. for 20 minutes.
When the thickness of the undercoat layer after drying was measured, it was 2 μm.

3) Formation of Charge Generation Layer The following materials were put in a ball mill and milled for 72 hours. Charge generating agent represented by the following structural formula 1 10 parts by weight Polyvinyl butyral 7 parts by weight Tetrahydrofuran 145 parts by weight

[Chemical 1] Further, 200 parts by weight of cyclohexanone was added and dispersed for 1 hour. The liquid after the dispersion was further diluted with cyclohexanone and adjusted to obtain a charge generation layer coating liquid. The charge generation layer coating liquid was roll-coated on the conductive support on which the undercoat layer was formed, dried at 100 ° C. for 10 minutes and dried to form a charge generation layer.

4) Formation of charge transport layer The following materials were dissolved to prepare a charge transport layer coating solution.     7 parts by weight of charge transport agent represented by the following structural formula 2     Polycarbonate (Panlite C-1400, made by Teijin) 10 parts by weight     Tetrahydrofuran 83 weight     Silicon oil 0.001 parts by weight

[Chemical 2] The charge transport layer coating liquid was applied onto the support having the charge generation layer formed thereon by die coating and dried at 120 ° C. for 30 minutes to form a charge transport layer. When the thickness of the charge transport layer after drying was measured, it was 28 μm.

The electrophotographic photoreceptor sheet thus prepared was used as a sheet-shaped electrophotographic photoreceptor for use in the following Examples and Comparative Examples.

(Example 1) An electrophotographic photosensitive sheet was placed on a glass plate, a stainless steel ruler was placed on the sheet, and cut along the stainless steel ruler to a predetermined size using an NT cutter manufactured by NTT Corporation. went. This was piled up on a steel joining table so as to have an overlapping width of 0.5 mm, fixed by vacuum suction, and joined by an ultrasonic joining horn.
At this time, the distance from the end of the superposed sheet-shaped electrophotographic photosensitive member to the surface of the lower sheet-shaped electrophotographic photosensitive member was 30 μm. In addition, the gap between the sheets in the overlapping portion was 30 μm. The ultrasonic transducer has a frequency of 28.
At 5 KHz, amplitude 35 μm, scanning speed 7 mm / se
c, 600 g of a weight was applied to press the vibrator.

(Example 2) An electrophotographic photosensitive sheet was placed on a glass plate, a stainless steel ruler was placed on the sheet, and cut along the stainless steel ruler to a predetermined size using an NT cutter manufactured by NT Co., Ltd. went. This was superposed on a steel joining table so as to have an overlap width of 0.7 mm and fixed by vacuum suction, and joined by an ultrasonic joining horn in the same manner as in Example 1 (the gap between the sheets in the overlapping portion was 30 μm). went.

(Example 3) An electrophotographic photoreceptor sheet was placed on a glass plate, a stainless steel ruler was placed on the sheet, and cut along the stainless steel ruler to a predetermined size using an NT cutter manufactured by NTT Corporation. went. This was piled up on a steel joining table so as to have a piling width of 0.5 mm and fixed by vacuum suction, and an ultrasonic horn made of duralumin was used in the same manner as in Example 1 (the gap between the sheets in the overlapping part was 30 μm).
m) Bonding was performed. At this time, the difference in horn tip temperature before and after joining was 3.6 ° C.

(Example 4) An electrophotographic photosensitive sheet was placed on a glass plate, a stainless steel ruler was placed on it, and cut along the stainless steel ruler to a predetermined size using an NT cutter manufactured by NT Co., Ltd. went. This was superposed on a steel joining table so as to have an overlapping width of 0.5 mm and fixed by electrostatic suction, and joined by an ultrasonic joining horn in the same manner as in Example 1 (the gap between the sheets in the overlapping portion was 30 μm). I went.

Example 5 A glass plate having a thickness of 120 μm
The electrophotographic photosensitive sheet of No. 1 was placed, a stainless steel ruler was placed on the sheet, and an NT cutter manufactured by NT Co., Ltd. was used to cut along the stainless steel ruler to a predetermined size. This was stacked on a steel joining table so as to have an overlapping width of 0.5 mm and fixed by vacuum suction, and joining was performed in the same manner as in Example 1 (the gap between the sheets in the overlapping portion was 30 μm).
At this time, the distance between the horn tip and the joining table is 100 μm.
The thickness of the fusion-bonded part after joining was 166 μm.
Met.

(Embodiment 6) An electrophotographic photoconductor sheet is used for IT.
After cutting with a rotary cutter NC-623 made by O, this was piled up on a steel joining table so as to have an overlap width of 0.5 mm and fixed by vacuum suction, and joining was carried out in the same manner as in Example 1. At this time, the jig shown in FIG. 2 was attached to the horn, and a pressure of 50 KPa was constantly applied to the overlapping portion 1.0 mm before the passage of the horn during the joining. In addition, the distance from the edge of the superposed electrophotographic photosensitive sheet to the surface of the lower electrophotographic photosensitive sheet is 5
was μm. In FIG. 2, 3 is an ultrasonic fusing horn, 4
Is a weight serving as a pressing force at the time of ultrasonic bonding, 2 is an ultrasonic oscillator, 5 is a joining table made of steel, and 7 is a weight for applying pressure to the overlapping portion of the electrophotographic photosensitive sheet. FIG. 3 is a diagram showing a sheet overlapping state when the overlapping portion of the joined sheets before joining is not pressed, and FIG. 4 shows a sheet overlapping state when holding the overlapping portion of the joined sheets. FIG. In FIG. 3, the upper sheet 61 is floating, but in FIG. 4, the upper sheet 61 is pressed by the lower sheet 62. It should be noted that the weight for pressing the sheet is not shown in FIG.

(Embodiment 7) The electrophotographic photoreceptor sheet is used for IT
After cutting with an O-made rotary cutter NC-623, this was laminated on a steel joining table so as to have an overlapping width of 0.5 mm and fixed by vacuum suction, and joining was carried out in the same manner as in Example 6. At this time, a pressure of 45 KPa was applied to the superposed portion 0.7 mm before passing the horn. In addition, the distance from the edge of the superposed electrophotographic photosensitive sheet to the surface of the lower electrophotographic photosensitive sheet is 5
was μm. Since this interval cannot be measured at the time of joining, another joining was performed, the joining was stopped in the middle, and only the ultrasonic horn was retracted for measurement.

(Embodiment 8) An ITO electrophotographic photosensitive sheet having a thickness of 120 μm is attached to an ITO rotary cutter NC-623.
After cutting with the above, the electrophotographic photosensitive sheet which becomes lower when stacked on the lower step on the steel joining table shown in FIG. The electrophotographic photosensitive member sheet was placed, fixed by vacuum suction force, and joined in the same manner as in Example 1. At this time, the gap between the step and the cut surface of the electrophotographic photosensitive sheet under the overlap is 2.5 mm, and the distance from the end of the superposed electrophotographic photosensitive sheet to the surface of the lower electrophotographic photosensitive sheet. Was 15 μm. In this figure, 3 is an ultrasonic fusing horn, 2 is a photosensitive layer, 3 is a plastic film, and 4 is a steel joining table which is stepped.

(Example 9) An electrophotographic photosensitive sheet was placed on a glass plate, and a stainless steel ruler having an inclined end face was placed on the sheet, and the stainless steel ruler was used to align with the NTT Corporation.
The manufactured NT cutter (hereinafter referred to as a cutter knife) was inclined and cut into a predetermined size. When the cut surface was observed with an optical microscope, it was confirmed that the cut surface was inclined from the vertical direction with respect to the bottom surface of the electrophotographic photosensitive sheet. The electrophotographic photosensitive sheet thus cut was joined by an ultrasonic joining horn in the same manner as in Example 1. At this time, the distance from the edge of the upper electrophotographic photosensitive sheet that was superposed to the surface of the lower electrophotographic photosensitive sheet was 20 μm.

(Comparative Example 1) The electrophotographic photosensitive member sheet was cut with an ITO rotary cutter NC-623 with the photosensitive layer surface facing upward. This was bonded in the same manner as in Example 1 with an ultrasonic bonding horn. At this time, the distance from the edge of the superposed upper electrophotographic photosensitive sheet to the surface of the lower electrophotographic photosensitive sheet was 50 μm.

(Comparative Example 2) An electrophotographic photosensitive sheet was placed on a glass plate, a stainless steel ruler was placed on it, and cut along the stainless steel ruler to a predetermined size using an NT cutter manufactured by NT Co., Ltd. went. Overlap this 0.2m
Example 1 was overlapped and fixed by vacuum suction.
Same as above (however, the gap between the sheets in the overlapping part is 40
μm) Bonding was performed.

(Comparative Example 3) An electrophotographic photosensitive sheet was placed on a glass plate, a stainless steel ruler was placed on the sheet, and cut along the stainless steel ruler to a predetermined size using an NT cutter manufactured by NT Co., Ltd. went. Overlap width 1.7m
Example 1 was overlapped and fixed by vacuum suction.
Same as (but the gap between the sheets in the overlapping part is 50
μm) Bonding was performed.

(Comparative Example 4) An electrophotographic photosensitive sheet was placed on a glass plate, a stainless steel ruler was placed on the sheet, and cut along the stainless steel ruler to a predetermined size using an NT cutter manufactured by NTT Corporation. went. This was stacked on a steel joining table so as to have an overlapping width of 0.5 mm and fixed by vacuum suction, and a Monel ultrasonic horn having a super steel tip at its tip was used in the same manner as in Example 1 (however, The gap between the sheets in the overlapped portion was 50 μm). At this time, the difference in horn tip temperature before and after joining was 12.0 ° C.

Comparative Example 5 An electrophotographic photosensitive sheet was placed on a cutter mat, a stainless steel ruler was placed thereon, and an ultrasonic cutter was used along the stainless steel ruler to cut into a predetermined size. This was placed on a steel joining table so as to have an overlapping width of 1.0 mm. At this time, the electrophotographic photoreceptor sheet was not fixed. After that, the joining was performed in the same manner as in Example 1, but the joining was not possible because the electrophotographic photosensitive sheet was displaced during the joining.

Comparative Example 6 A glass plate having a thickness of 120 μm
The electrophotographic photosensitive sheet of No. 1 was placed, a stainless steel ruler was placed on the sheet, and an NT cutter manufactured by NT Co., Ltd. was used to cut along the stainless steel ruler to a predetermined size. This was stacked on a steel joining table so as to have an overlapping width of 0.5 mm and fixed by vacuum suction, and joining was performed in the same manner as in Example 1 (however, the gap between the sheets in the overlapping portion was 70 μm). At this time, the distance between the horn tip and the joining table is 2
When fixed to 40 μm, the thickness of the fused part after joining was 2
It was 06 μm.

(Comparative Example 7) An electrophotographic photosensitive sheet was used for IT.
It cut | disconnected by the rotary cutter NC-623 made from O, it piled up on the joining table made from steel so that it might become 0.5 mm in width, and it fixed by vacuum suction. This was joined in the same manner as in Example 6 except that the pressure for holding the overlapping portion was set to 10 kPa. However, the distance from the end of the upper electrophotographic photosensitive sheet that was superposed to the surface of the lower electrophotographic photosensitive sheet was 45 μm. Since this interval cannot be measured at the time of joining, another joining was performed, the joining was stopped in the middle, and only the ultrasonic fusing horn was retracted for measurement.

(Comparative Example 8) An electrophotographic photosensitive sheet was used for IT.
It cut | disconnected by the rotary cutter NC-623 made from O, it piled up on the joining table made from steel so that it might become 0.5 mm in width, and it fixed by vacuum suction. Bonding was performed in the same manner as in Example 6 except that the pressure for holding the overlapping portion was set to 200 kPa, but the sheet-shaped electrophotographic photosensitive member was displaced at the portion to which the pressure was applied and could not be bonded.

(Comparative Example 9) An electrophotographic photosensitive sheet was used for IT.
It cut | disconnected by the rotary cutter NC-623 made from O, it piled up on the joining table made from steel so that it might become 0.5 mm in width, and it fixed by vacuum suction. Example 6 except that the position where the overlapping portion is held is 15 mm before the ultrasonic fusing horn.
Bonded in the same way. However, the distance from the end of the upper electrophotographic photosensitive sheet that was superposed to the surface of the lower electrophotographic photosensitive sheet was 50 μm.

(Comparative Example 10) A rotary cutter NC-62 made of ITO was used as an electrophotographic photosensitive sheet having a thickness of 120 μm.
After cutting at 3, the electrophotographic photosensitive member sheet was placed on the same steel joining table as in Example 8 provided with a step of 20 μm and fixed by vacuum suction force, and joining was performed in the same manner as in Example 1. It was At this time, the gap between the step and the cut surface of the electrophotographic photosensitive sheet below the overlap is 2.5 mm, and from the end of the superposed electrophotographic photosensitive sheet to the surface of the lower electrophotographic photosensitive sheet. Was 45 μm.

(Comparative Example 11) A rotary cutter NC-62 made of ITO was used as an electrophotographic photosensitive sheet having a thickness of 120 μm.
After cutting at 3, the electrophotographic photosensitive sheet was placed on the same steel joining table as in Example 8 provided with a step of 180 μm and fixed by vacuum suction force, but as in Example 1 (however, Although the gap between the sheets in the overlapped portion was 50 μm), they were joined, but the electrophotographic photosensitive sheets were misaligned and could not be joined.

(Comparative Example 12) When the electrophotographic photosensitive sheets were superposed, the upper side was placed on a glass plate,
A stainless ruler was placed on it, and cutting was performed with a cutter knife along the stainless ruler. The lower side was cut with an ITO rotary cutter NC-623. When the cut surface of the lower electrophotographic photosensitive member sheet was observed with an optical microscope, it was confirmed that the cut surface was substantially perpendicular to the bottom surface of the sheet. After that, these electrophotographic photosensitive sheets were stacked on a steel joining table so as to have a stacking width of 0.5 mm and fixed by vacuum suction,
Bonding was carried out with an ultrasonic bonding horn in the same manner as in Example 1. At this time, the distance from the end of the superposed electrophotographic photosensitive sheet to the surface of the lower electrophotographic photosensitive sheet was 40 μm.

The endless belt type photoconductors prepared in Examples 1 to 9 and Comparative Examples 1 to 12 were evaluated.
Bonding strength is Minebea's universal tensile compression strength tester M
Sample width 10 using odel TCM-200CR
mm and a pulling speed of 200 mm / min. The measurement results are shown in Table 1. When the electrophotographic photosensitive sheets were superposed, the distance between the top of the upper sheet and the surface of the lower sheet was measured through a stainless steel plate of known thickness.

[0084]

[Table 1]

In each of Examples 1 to 9, 13.0 kgf /
There was a bonding strength of cm or more. At this time, the gap between the top end of the upper sheet and the top surface of the lower sheet is 35
It was less than μm. No abnormal noise can be heard during welding, and it is estimated that ultrasonic energy is used efficiently for welding. On the other hand, all the comparative examples had a bonding strength of 13.0 kgf / cm or less, and when they were overlapped with each other, the gap between the tip of the upper sheet and the surface of the lower sheet was 35 μm or more. It was also confirmed that there was a partial noise during the joining when the joining was insufficient.

[0086]

EFFECTS OF THE INVENTION According to the present invention, since the gap between the films in the overlapping portions of the films is set to 35 μm or less and they are bonded by the ultrasonic fusing horn, excellent bonding can be performed.

[Brief description of drawings]

FIG. 1 is a schematic view of an ultrasonic bonding apparatus preferably used in the present invention.

FIG. 2 is another schematic view of the ultrasonic bonding apparatus preferably used in the present invention.

FIG. 3 is a diagram showing a superposed state of sheets when the superposed portions of the joined sheets before joining are not pressed.

FIG. 4 is a diagram showing a state in which sheets are superposed when the superposed portions of the sheets to be joined before pressing are being held.

FIG. 5 is a diagram showing a state in which sheets to be joined are joined on a joining table provided with steps.

[Explanation of symbols]

1 Electronic Thickness Unit 2 Ultrasonic Oscillator 3 Ultrasonic Fusing Horn 4 Weights 5, 51 Joining Table 6 Sheet-shaped Plastic Sheet or Electrophotographic Photosensitive Sheet (6a Conductive Film, 6b Conductive Layer) 7 Weights 61, 62 Joined Sheet

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H035 CA05 CB06                 2H068 AA52 AA55 BB23 BB25 EA05                       EA40 FA08 FA23                 4F211 AA24 AD05 AD08 AG16 TA01                       TC09 TD11 TH02 TH06 TH10                       TJ22 TJ23 TJ30 TN22

Claims (13)

[Claims] 1. A superposition part is joined by superposing both edges of a plastic film and moving the superposition horn that is oscillating onto the superposition part while pressing the oscillating ultrasonic fusing horn. In the way
A method for joining plastic films, characterized in that, when the plastic films are superposed before joining, the distance between the upper film tip and the lower film surface is 35 μm or less. 2. The joining method according to claim 1, wherein the thickness of the plastic film is 70 μm or more and 250 μm or less, and the overlapping width of the plastic film before joining is 0.3 mm or more and 1.5 mm or less. A method for joining plastic films, characterized in that 3. The joining method according to claim 1, wherein the temperature difference between the horn tip at the joining start point and the end point of the joining is 10 ° C.
A method for joining plastic films, characterized in that: 4. The method for joining plastic films according to claim 1, 2 or 3, wherein the plastic film is fixed to the joining table by vacuum suction or electrostatic attraction during ultrasonic joining. 5. The bonding method according to claim 1, wherein the thickness of the fusion-bonded portion after bonding is 1 time or more and 1.6 times or less the thickness of a portion that is not the fusion-bonded portion. A method for joining plastic films, characterized in that 6. The joining method according to claim 1, wherein the plastic film immediately before the ultrasonic fusion horn passes is mechanically held down, and when the plastic films are superposed before joining, The method for joining plastic films, wherein the distance between the film tip and the film surface below is 35 μm or less. 7. The joining method according to claim 6, wherein the position for mechanically holding the plastic film is 0.5 mm or more before the horn in the traveling direction of the ultrasonic fusion horn.
A method for joining plastic films, wherein the bonding method is less than or equal to mm. 8. The method for joining plastic films according to claim 6, wherein the pressure for holding the overlapping portions of the plastic films is 25 kPa or more and 125 kPa or less. 9. The joining method according to claim 1, wherein a step is provided on a table on which the plastic film is placed, and when the plastic films are superposed before joining, the top end of the upper film and the bottom surface of the film. Interval of 35
A method for joining plastic films, which has a thickness of less than or equal to μm. 10. The joining method according to claim 9, wherein the height of the step provided on the table on which the plastic film is placed is 0.2 times or more and 1.4 times or less the thickness of the plastic film. How to join plastic films. 11. The joining method according to any one of claims 1 to 5, wherein when the plastic films are superposed before the joining, the whole end surface of the sheet or the upper part thereof is inclined, and when the plastic films are superposed, the upper end is provided. The method for joining plastic films, wherein the distance between the front end of the film and the surface of the underlying film is 35 μm or less. 12. An endless belt-shaped electrophotographic photosensitive member manufactured by being bonded by the bonding method according to claim 1. 13. An electrophotographic apparatus comprising the endless belt-shaped electrophotographic photosensitive member according to claim 12.