JPS6233938B2 - - Google Patents

Abstract

PURPOSE:To obtain a smooth bonded surface which has no stepped difference of dielectric films of multilayer structure by covering a heat softening substance on the surfaces to be bonded of the films when bonding the films, superposing the films, and applying a supersonic wave to the films while applying a pressure to the films from a supersonic horn. CONSTITUTION:When transfer type recording media each of which has a supporting layer 30 and a recording layer 22 made of polyethylene terephthalate films and a resistance layer 21 made of acrylic resin are bonded, the end portions to be bonded of the media are covered with the same acrylic resin film as the material of the layer 21 of the medium, are superposed, are placed on a lower bearer 2, a supersonic wave is applied while pressurizing the media from a supersonic horn 1, thereby bonding the media. In this manner, the smooth bonded surface which has no stepped difference of the media can be obtained, and clogging of toner or the like can be prevented. A further smooth bonded surface can also be obtained by providing a supersonic energy buffer material 25 between the bearer 2 and the media to be bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining dielectric films, particularly belt-shaped dielectric films used in the field of transfer electrostatic recording, particularly multilayer dielectric films.

Conventionally, a belt-shaped dielectric film used in an electrostatic recording device is formed by joining a long sheet material at each end so that a recording layer is provided on the outside and a base layer is provided on the inside. There is. The joined dielectric film becomes an endless belt, and when an image is to be formed on the recording layer except for the joined part, for example, a charging process using a multi-needle electrode, a powder development process, and then the powder image is transferred to plain paper. and fixing the powder image on the paper. On the other hand, the powder remaining on the dielectric film is cleaned by a blade, and the dielectric film is repeatedly reused. The dielectric film, which is made up of a long endless belt, is timed so that image formation is performed in areas other than the joints, so there is no possibility of dirt from developing powder at the joints or charging as a recording medium. We try to avoid differences in characteristics, etc. Also,
When charging a dielectric film with this type of device, the action is applied from the lateral direction of the long endless belt, so the recording layer, resistance layer, and base layer do not need to be connected at the joint of the belt. It has nothing to do with image formation.

2. Description of the Related Art Conventionally, there is a method shown in FIG. 1 as a method of bonding dielectric films together, in which a plurality of films or substances of different compositions are laminated to form a single structure. In this method, the dielectric material to be bonded is placed between an ultrasonic horn and a lower pedestal, pressure is applied while applying ultrasonic waves to the horn, and the dielectric material is bonded by heat action. However, as shown in FIG. 2, the bonded surfaces bonded by this method have a drawback in that a step (approximately 30% relative to the thickness) occurs in the bonded surfaces.

In order to improve this, in a patent application filed on the same day as this application, the inventor provided one or more ultrasonic energy buffer layers between the dielectric material and the lower pedestal as shown in Figure 3. , proposed a method to supply ultrasonic energy and pressure.

However, even with this method, for example, in the case of an electrostatic recording medium in which a resistance layer 21 and a recording layer 22 are provided on a base layer 20, the recording layer 10 is made of a substance with a high softening point (for example, polyethylene terephthalate, etc.). In this case, there were cases where a slight step remained on the joint surface. When such a level difference occurs, for example, in the case of a transfer type electrostatic recording method, toner etc. may become clogged.
This caused the multi-needle electrode to become dirty when running for a long period of time.

An object of the present invention is to provide a joining method that eliminates the above-mentioned drawbacks.

That is, the present invention provides a new method for bonding composite dielectric films, such as electrostatic recording media or electrophotographic recording media, in which films or substances of different compositions are superimposed, which eliminates the level difference at the bonded portion and provides a smooth surface. The purpose is to provide a suitable joining method.

The purpose of the present invention is to fabricate a dielectric film (see Figure 4) made by laminating a plurality of members with different compositions using an ultrasonic bonding device consisting of an ultrasonic horn and a lower pedestal that receives the pressure of the horn. The bonding method is characterized by coating the parts of the dielectrics to be bonded with a heat-softening substance, overlapping them and placing them on a lower pedestal, and applying ultrasonic waves while applying pressure with an ultrasonic horn. This can be achieved by a dielectric film bonding method.

Further, the object of the present invention can be more effectively achieved by a joining method in which at least one ultrasonic energy buffer material is provided between the lower pedestal and the dielectric material to be joined.

In the present invention, the material covering the portions of the dielectric film to be joined is preferably a heat-softening material of the same type as at least one component of the dielectric film.

However, other thermoplastic resins can be used as long as they are compatible with the composite dielectric material when heated and have good thermal conductivity.

The joining method of the present invention will be described with reference to an example using a transfer type electrostatic recording belt.

Using an ultrasonic horn with an effective horn width of 20 mm and a longitudinal distance of 300 mm, a transfer type recording medium (thickness 100μ), first overlap the edges by 2mm without coating the overlapping edges, then apply two layers of tape made of 50μ thick cellophane coated with 30μ adhesive to the back side, and apply pressure.
When welding was carried out under the conditions of 50 psi, ultrasonic energy of 2 KW, and application time of 2.0 seconds, the result was 10 as shown in Figure 6.
A level difference of about μm was created.

On the other hand, as shown in Fig. 5, the ends to be bonded were covered with an acrylic resin film (thickness: 10 μm), which is the same as the resistance layer material, and bonding was performed under the same conditions as above (see Fig. 8). As shown in FIG. 7, an almost smooth surface with a level difference of about 1 μm was obtained.

Using the electrostatic recording material bonded in this way, charging with a multi-needle electrode, powder development, transfer to plain paper, and cleaning with a blade were performed. In recording bodies bonded by the conventional method without coating the cross-sectional view, the multi-needle electrode began to become dirty after 5,000 copy cycles, but in recording bodies bonded by the method of the present invention, fouling did not occur, and was caused by toner fouling. There was no visible missing part of the statue.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the conventional method of joining multilayer structure recording bodies using ultrasonic waves, Fig. 2 is a cross-sectional view of the joining surface by the method of Fig. 1, and Fig. 3 is an explanatory diagram of the improved joining method of Fig. 1. , FIG. 4 is a cross-sectional view of the three-layer structure recording medium, and FIG.
The figure is a cross-sectional view of a recording medium whose edges are coated with a softening resin, FIG. 6 is a cross-sectional view of a bonded surface obtained by the method of FIG. 3, and FIG. 7 is a cross-sectional view of a bonded surface obtained by the method of the present invention. 8 is a sectional view showing the joining method of the present invention. Codes in the figure: 1... Ultrasonic horn, 2... Lower pedestal, 3... Dielectric, 20... Base layer, 21...
Resistance layer, 22... Recording layer, 24... Adhesive layer, 25
...Buffer layer, 30...Thermosoftening resin.

Claims (1)

[Claims] 1. A method for bonding dielectric films formed by laminating a plurality of members having different compositions using an ultrasonic bonding device consisting of an ultrasonic horn and a lower pedestal that receives pressure from the horn. , a dielectric film characterized in that the parts of the dielectric to be joined are coated with a heat-softening substance, the parts are overlapped and placed on a lower pedestal, and ultrasonic waves are applied while applying pressure with an ultrasonic horn. Joining method. 2. The joining method according to claim 1, characterized in that at least one ultrasonic energy buffering material is provided between the lower pedestal and the dielectric material to be joined.