JP2632265B2 - Joint application method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the detection of a joint portion of a continuously running belt-shaped flexible support (hereinafter referred to as "web") in the production of photographic materials such as photographic film and photographic paper. And applying various liquid compositions to the composition.

[0002]

2. Description of the Related Art As a method of coating a web joint, various measures have been taken to reduce loss due to thick coating or uneven coating occurring at the joint. A web bonding method in which a flexible adhesive tape is attached to the front surface of the rear end portion of the front web and the rear surface of the front end portion of the rear web (see JP-A-54-34343). (See JP-A-54-62241) A method of previously filling the gap on the coated surface of the web joint with a fusible material (see JP-A-58-501679) Immediately before coating, the liquid injector is separated from the coating web, and the liquid injector is returned to its original position after passing through the joint (see JP-A-58-88074). (Japanese Unexamined Patent Publication No. 55-142565, Japanese Unexamined Patent Publication No. 2-26593)
No. 0) is disclosed. In addition, as a method of coating a web which is not limited to a joining portion, a method of applying a high voltage to a coating backup roller to prevent liquid shortage between a liquid injector and a web and increasing a coating speed (Japanese Patent Publication No. 49-7050) Japanese Patent Application Laid-Open No. 1-214141 discloses a method of applying a high-voltage direct current to a discharge electrode to apply a unipolar charge to the surface of a web by corona discharge and applying the same. Are bonded together using an adhesive tape having a conductive layer such as aluminum vapor-deposited and detected by a metal detector (Japanese Patent Laid-Open No. 2-265).
No. 930)

[0003]

SUMMARY OF THE INVENTION However,
In the methods (1) and (2), there is a problem that a web joining process becomes complicated, and it takes time to form a joined portion, thereby lowering productivity.
The method (1) has a problem that the flow of the liquid to be applied is disturbed because the liquid injector (coating head) moves rapidly. The method of (1) applies a high-frequency high voltage to the discharge electrode before and after the web joint, and performs processing by applying positive and negative charges formed on the web surface after processing. There is a problem that occurs. In the method of applying a DC high voltage to the application backup roller in the method described above, or when applying a DC high voltage to the discharge electrode to form a unipolar charge on the web surface by corona discharge as in the other method, the positive and negative charges are used. Coating unevenness does not occur, but when an adhesive tape having a conductive layer is used as in the method for joining webs, the shielding effect of the conductive layer and the thickness of the insulating (supporting member) of the adhesive tape are small, so that the thickness of the joining portion is small. When the electrostatic capacity becomes excessive, the surface potential of the web on the application backup roller is lowered, and there is a problem in that the effect of suppressing the running out of the application liquid between the liquid injector and the web is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, not to complicate the joining process, to prevent application unevenness, and to prevent the application liquid from running out between the injecting device and the web joining portion. It is an object of the present invention to provide a method for applying a joint portion capable of significantly improving the speed.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a connecting portion joined to an end of a continuously running strip-shaped flexible support by abutting the end of the flexible support and joined by an adhesive tape. In the method of applying a coating liquid while supporting it with a coating backup roller, a black layer is provided on the adhesive tape, and the support is irradiated with infrared light at a sending-out portion to transmit the infrared light or the infrared light transmitted through the support. The amount of infrared light reflected by the support is measured, and when the amount of change in the amount of light deviates from a predetermined value, it is determined that the joint of the support has passed, and the joint on the application backup roller is determined. Is applied by charging the surface potential to 0.5 to 2.0 kV.

[0006] In the present invention, the application by charging the surface potential of the joining portion on the coating backup roller to 0.5 to 2.0 kV means that the monopolar coating is applied to the support by corona discharge. There are a method of applying a charge and a method of applying a DC voltage to the application backup roller. About 100 μm to 200 μm in diameter
Using a wire-shaped conductive material having a length of at least 1 kg, a wire is stretched while maintaining the tension at 1 kg or more, and a plurality of wires having an intermediate holding frame for holding the wire electrodes at a distance of ≦ 300 mm are separated by at least 20 mm in the length direction of the wire. It is preferable to use a staggered arrangement in which the distance between the wire electrode and the web is smaller at the end of the wire than at the center of the wire. As a result, potential fluctuations in the web transport direction and width direction can be minimized, and coating unevenness due to potential fluctuations can be reduced. (See Japanese Patent Application No. 2-174467)
In the case of using the coating backup roller, the journal portion of the application backup roller is coated with a ceramic insulating coating, supported by a fluid bearing, and a rotating terminal that extends the shaft uses a connection terminal other than a brush type slip ring as a connection terminal. It is preferable to connect a DC high voltage power supply. As a result, the deflection of the rotation is reduced as compared with the case where the conventional bearing is a ball bearing, and a high voltage of 0.5 to 3 kV can be applied more uniformly than when a brush type slip ring is used (Japanese Unexamined Patent Application Publication No. Hei. According to the above method or the above method, a surface potential of 0.5 to 2.0 kV can be realized as a monopolar surface potential of the support joining portion on the application backup roller. Preferably, the surface potential of the support junction is 1-2 kV. As a result, an electrostatic attraction acts between the support joining portion and the liquid injector, thereby promoting the adhesion of the coating solution to the surface of the joining portion and suppressing the application solution from running out.

In the present invention, in the butt joining of the support,
Using an adhesive tape having a black layer without using an adhesive tape having a conventional conductive layer means that the capacitance of the adhesive tape having the conventional conductive layer is smaller than the capacitance of the support. The problem is to eliminate the point that is several tens of times too large. In the case of an adhesive tape having a conductive layer, the thickness of the insulator (generally a support member) outside the conductive layer (surface side) is smaller than that of the support, and the capacitance is inversely proportional to the thickness of the insulator. In addition, the capacitance of a capacitor composed of a conductive layer and an insulator outside the conductive layer becomes considerably large. When a monopolar electrostatic charge is applied to the surface of the support joint by the above method, the amount of current that can be supplied by a precise DC high-voltage power supply having no ripple in the voltage waveform used is relatively small. The surface potential of the support junction decreases to about one-tenth of the surface potential of the support. In addition, in the case of the above method, the surface potential of the support joining portion on the application backup roller decreases due to the shielding effect of the conductive layer of the adhesive tape. The surface potential of the support joint is 0.5 to 2.0
In order to suppress the application liquid from running out at kV, it is necessary to use an adhesive tape which is an insulator. In the case where the adhesive tape is an insulator similar to the support, as a method of detecting the joint of the support instead of the conventional metal detector, a black layer is provided on the adhesive tape and the determination is made based on the amount of change in the amount of transmitted or reflected infrared light. This means that when the support is irradiated with infrared light having a wavelength of 820 nm or more using an LED or the like as a light source and transmitted light or reflected light is detected by a photodiode or the like, the black layer of the adhesive tape at the support joint portion is detected. Since the infrared light is almost completely absorbed by the light-emitting device, the amount of infrared light detected by the photodiode changes greatly, so that the joint portion of the support can be easily determined. Furthermore, since infrared rays are used, even when the liquid composition of the photographic light-sensitive material is applied to the support, the joint of the support can be detected without damaging the photographic light-sensitive material. As the black layer of the adhesive tape in the present invention, a coating material in which an inorganic pigment such as carbon black or an organic pigment such as aniline black is dispersed in a solvent in which a resin or a cellulose derivative is dissolved is applied to a support member of the adhesive tape and dried. I can get it. From the viewpoint of scratch resistance, the black layer is preferably not provided on the outer surface of the adhesive tape, but is preferably provided between the support member and the adhesive layer. In the present invention, in order to set the surface potential of the support joint on the coating back aap roller to 0.5 to 2.0 kV, the moving distance from the passage of the support joint to the discharge portion to the discharge portion is set. When the surface potential is obtained by corona discharge, by applying a high DC voltage to the corona discharge electrode immediately before the support joint reaches the corona discharge electrode, The method of applying a high voltage is achieved by starting to apply a DC high voltage to the application backup roller immediately before the support joint reaches the application backup roller.

The embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a method of applying a unipolar electrostatic charge to the surface of a support joint by corona discharge. After passing through, it reaches a pass roller 9 which is a ground electrode provided opposite to the corona discharge electrode 3. Immediately before this, a high voltage is supplied from the DC high-voltage power supply 4 to the corona discharge electrode 3, corona discharge starts, and a monopolar charge is applied to the surface of the support joint 1. Thereafter, the support joint 1 is applied to the application backup roller 5 by the liquid injector 6 to apply the application liquid 7.
Is given. FIG. 2 shows a method of applying a DC high voltage to the application backup roller. After the support joint 1 passes through the joining detector 2 and immediately before reaching the application backup roller 5, the DC high voltage is supplied from the DC high voltage power supply 4. The application of the voltage to the application backup roller 5 is started, and
And a coating liquid 7 is applied to the support junction 1 by a liquid injector 6.

[0009]

The present invention will be described in more detail with reference to an embodiment. However, the present invention is not limited only to this embodiment. (Example-1) As a web (support), a resin coated paper of polyethylene was used, and a coated layer having a thickness of 220 µm was provided with a gelatin layer having a thickness of 0.3 µm and an alumina sol layer provided on a back surface thereof, respectively. . Web width is 1.
4 m, the surface roughness of the surface to be coated is average roughness Ra = 4 to 5 μm
Met. Further, a web obtained by applying a color paper coating solution to the web and drying the web was also used. The layer constitution of the color paper photosensitive layer was composed of three photosensitive layers containing silver halide, three color filter layers and one protective layer, and the total thickness of the layers was 10 μm. 25 μm thick polyethylene terephthalate (PET) with 0.3 μm thick gelatin layer as an adhesive tape for butt joining of web ends
Was used as a supporting member, and another PET surface provided with a black layer and a glue layer was prepared. The thickness of the adhesive tape was 50 μm. For comparison, a transparent tape in which only the adhesive layer was provided on the PET surface of the support member was also prepared. There was no difference between the two adhesive tape thicknesses. The infrared sensor PG-602 manufactured by Keyence Co., Ltd. in which the light source unit 2a and the light receiving unit 2b are separated was used as a support joint detection sensor. For comparison, an ultrasonic sensor PC checker manufactured by Nireco Co., Ltd. was used. The distance between the light source unit 2a (or transmitting unit) and the light receiving unit 2b (or receiving unit) of the detection sensor was 30 mm. FIG.
Was evaluated as to whether or not the joint portion of the web running at a speed of 5 m / sec was detected. Table 1 shows the results.

[0010]

[Table 1]

In Table 1, the embodiment of the present invention is a combination using an infrared sensor and an adhesive tape provided with a black layer, and the other three combinations are comparative examples. ADVANTAGE OF THE INVENTION According to this invention, the butt joint part can be detected in the web which has been coated with the color paper liquid and the web which has not been coated.

Example 2 Next, the uncoated web in Example 1 was used as the web, and the color paper coating liquid described in Example 1 was used as the coating liquid. However, the application amount of the coating solution: web area 1 m ² per meter 100 ml, those of the lowermost yellow coloring layer
The properties and coating conditions were as follows : gelatin concentration: 6% by weight, viscosity (at a shear rate of 50 sec ^-1 ): 40 mPa · s, and applied amount: 14.4 ml / m ² . As the adhesive tape for web butt joining, a tape provided with the black layer described in Example-1 and a tape provided with the black layer described in Example-1 without the gelatin subbing layer were used. for,
An adhesive tape in which an aluminum vapor-deposited layer and a glue layer were provided as conductive layers on the adhesive tape support member (PET) described in Example 1 was used. Further, after a unipolar charge was applied to the support joint by corona discharge according to FIG. 1, a color paper coating solution was applied, and the running speed of the support at which the coating solution run out at the support joint was evaluated. The DC high voltage applied to the corona discharge electrode was adjusted so that the potential of the normal portion of the support on the application backup roller became a predetermined value, and the potential of the joint of the support on the application backup roller was measured. A Trek model 664 was used as a DC high voltage power supply, and a Trek model 334 was used for potential measurement. At the same time, the running speed of the support at which the coating liquid runs out at the support joint when no unipolar charge is given by corona discharge to the support joint using the adhesive tape provided with the black layer described in Example-1 is also increased. evaluated. As a method for applying the coating liquid, the slide bead method shown in FIG. 1 or FIG.
0 mmH ₂ O was set low, and the gap between the tip of the liquid injector and the application backup roller was 0.4 mm. Table 2 shows the results.

[0013]

[Table 2]

In Table 2, a unipolar charge is applied to the support joint using an adhesive tape provided with a black layer having no conductive layer, thereby preventing the coating solution from running out at the support joint. , Experiment No. 1 to No. As can be seen from FIG. 4, the limit coating speed can be increased. However, in the case of Experiment No. 5, the potential of the support junction was too high, and streaks were generated. Further, when an adhesive tape provided with a black layer having no conductive layer and having no gelatin subbing layer was used, the results of Experiment Nos. 7
As shown in FIGS. 10 to 10, it can be seen that a further increase in the limit speed can be achieved. Experiment No. The support joint using an adhesive tape having a conductive layer such as an aluminum vapor-deposited layer as shown in Fig. 6 has a large capacitance and a low potential due to the electric charge on the surface of the joint. It cannot be prevented.

[0015]

As described above, according to the method for coating a support joint according to the present invention, the support joint can be reliably detected, and further, the coating liquid at the support joint can be prevented from running out, and the coating limit speed can be reduced. Could be improved.

[Brief description of the drawings]

FIG. 1 is a schematic side view of one embodiment of an apparatus for performing a method of applying a support joint portion according to the present invention.

FIG. 2 is a schematic side view of another embodiment of the apparatus for performing the method of applying a support joint according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joint part of a support body 2 Detector of a joint part 3 Corona discharge electrode 4 DC high voltage power supply 5 Application backup roller 6 Injector 7 Application liquid 8 Decompression chamber

Claims (1)

(57) [Claims] 1. A method of applying a terminal of a continuously running belt-shaped flexible support to a terminal of a continuous flexible support, and applying the adhesive to a joint portion joined by an adhesive tape, while supporting the joint with an application backup roller. In the method of applying a liquid, a black layer is provided on the adhesive tape, and the support is irradiated with infrared light at a sending portion, and the amount of infrared light transmitted through the support or reflected by the support is measured. When the variation of the light amount deviates from a predetermined value, it is determined that the joint of the support has passed, and the surface potential of the joint on the application backup roller is set to 0.5 to 2.0 kV.
A method for applying a joint portion, wherein the method is applied by charging the substrate.