JP2890166B2 - Doctor knives in web coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a doctor knife in an apparatus for coating a web such as a film, a cloth, and a paper.

[0002]

2. Description of the Related Art Conventionally, there is a dam type coating apparatus 100 as shown in FIG. In the coating apparatus 100, a comma-type doctor knife 108 is provided above a backing roll 102, and a dam plate 10 is provided in front of the doctor knife 108.
4 to form a liquid reservoir 106.

When the coating liquid is applied to the web W, the coating liquid is stored in a liquid reservoir 106 formed by the dam plate 104, and the web W is run by the backing roll 102, and the backing roll 102 is moved. A coating liquid is applied to the web W by a gap between the doctor knife 102 and the doctor knife 108.

[0004]

However, in the coating apparatus 100 having the above-described structure, the coating pressure shown in FIG.
As shown in (1), a phenomenon in which the center of the cylindrical doctor knife 108 is curved upward, that is, bending may occur.

Therefore, conventionally, as a doctor knife for adjusting this bending, a pressure type doctor knife for injecting a fluid such as air or oil into the inside of the doctor knife to expand the doctor knife in the radial direction, or an adjusting screw in the radial direction is provided. A screw type doctor knife that adjusts bending by moving an adjusting screw in a radial direction has been proposed (Japanese Patent Publication No. 60-45949).

However, in the pressure type doctor knife, since the doctor knife is inflated by the fluid, the fluid has a cushioning property in the radial direction of the doctor knife. Therefore, the amount of bending could not be adjusted to be constant, and it was difficult to make the coating pressure uniform. Further, air or oil may leak from a pressure vessel, a tube, or the like for injecting a fluid inside the doctor knife, and the bending amount may not be properly controlled.

Further, in the screw type doctor knife, it is necessary to temporarily stop the coating device and adjust the screws, which is troublesome. Also, the measurement of whether or not the bending amount has changed requires that the coating apparatus is once stopped and then measured.

In view of the above problems, the present invention provides a doctor knife capable of finely adjusting the amount of bending even during operation of a coating apparatus.

[0009]

According to a first aspect of the present invention, there is provided a doctor knife for coating a web with a coating solution, wherein the doctor knife is formed in a cylindrical shape, and the center of the doctor knife is provided. A worm is arranged radially inside, a motor is provided inside the doctor knife, a worm gear for moving the worm in the radial direction is provided on a rotating shaft of the motor, and the worm is moved in the radial direction by the motor, Press the tip of the worm against the inner peripheral wall of the cylindrical doctor knife to expand it,
The bending amount of the doctor knife is adjusted.

[0010]

[Operation] The doctor knife in the web coating apparatus having the above configuration will be described.

When the doctor knife bends, the worm is moved in the radial direction, that is, in the direction in which the doctor knife is depressed by the motor provided inside the doctor knife, and the tip of the worm is pushed against the inner peripheral wall of the doctor knife. Then, the concave portion is pushed to expand, and the bending amount of the doctor knife is adjusted.

In this case, since the motor is provided inside the doctor knife, the amount of bending can be adjusted while operating the coating apparatus.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 10 denotes a comma-type doctor knife used in a coating apparatus. This cylindrical doctor knife 10
Is formed by an outer cylinder 12 and an inner cylinder 14, and the inner cylinder 14 is arranged concentrically with a gap 16 inside the outer cylinder 12.

Reference numerals 18 and 20 denote shaft portions provided at both ends of the inner cylinder 14. The shaft portion 18 is provided with a through hole 22 for passing an electric cord described later.

Reference numerals 24 and 26 denote ring-shaped edges provided at the peripheral edges of both ends of the outer cylinder 12.

Reference numerals 27 and 28 denote ring-shaped connecting rings for connecting the shafts 18 and 20 and the edges 24 and 26 concentrically. Specifically, as shown in FIG. 3, the inside of the connection ring 28 is pressed by the shaft portion 20 by a ring-shaped first pressing member 28a, and is fixed by bolts 28b arranged in the axial direction. Furthermore, connecting ring 2
The outside of 8 is pressed against the edge 26 by a ring-shaped second pressing member 28c, and is fixed by a bolt 28d. The outer cylinder 12 and the inner cylinder 14 are connected to the connecting ring 2.
The outer tube 12 can bend with respect to the inner tube 14 because the outer tube 12 is connected by the inner tube 8.

Reference numeral 30 denotes a central part of the inner cylinder 14.
It is a worm arranged in the diameter direction. This warm 30
Is. A bearing provided on the inner peripheral wall of the inner cylinder 14 is provided so as to be movable in the diameter direction and rotatable. Both ends of the worm 30 penetrate holes 38 and 40 provided in the inner cylinder 14 and protrude outward from the inner cylinder 14.

Reference numeral 32 denotes a worm gear for moving the worm 30 in the radial direction. The worm gear 32 is provided on a rotation shaft of a speed reducer 34.

Reference numeral 36 denotes a motor 36 for rotating the speed reducer 34, by which the worm 30 moves. The electric cord coming out of the motor 36 is
It is arranged outside through the through hole 22 of the shaft portion 18.

Reference numerals 42, 42 denote pressing members disposed between the gap 16 between the outer cylinder 12 and the inner cylinder 14. A central portion 44 of the U-shaped pressing member 42 is concave, and both end portions 46 thereof are provided.
Protrudes and presses the inner peripheral wall of the outer cylinder 12 only with the two end portions 46, 46.
Is pressed radially outward by the tip of the. Pressing member 4
2 is provided in a pair on the axis object. Therefore, when the worm 30 moves downward in FIG. 1, the lower pressing member 42 pushes up the central portion of the outer cylinder 12 downward, and when the worm 30 moves upward, the upper pressing member 42 Presses the inner peripheral wall of the outer cylinder 12 upward.

Reference numeral 48 denotes a gap sensor for measuring the size of the gap 16. This gap sensor 48 measures the size of the gap 16.

Reference numeral 50 denotes a dummy sensor provided at a position facing the gap sensor 48 with the pressing member 42 interposed therebetween. A metal is built in the dummy sensor 50, and when the metal expands due to the temperature, the measurement error due to the temperature of the gap sensor 48 is corrected with reference to the expansion ratio.

Reference numeral 52 denotes a control device for rotating the motor 36 in accordance with a signal from the gap sensor 48.
The measurement error caused by the temperature of the gap sensor 48 is corrected by the signal of the dummy sensor 50 (see FIG. 4). The traveling speed of the web W is detected by a motor 56 that rotates the backing roll 102.

A case where the doctor knife 10 having the above configuration is used in a dam type coating apparatus 100 shown in FIG. 6 will be described.

When the web W is transported by the backing roll 102, a coating liquid is supplied from a liquid reservoir 106 formed by the dam plate 104, and the coating liquid is supplied to the upper surface of the web W by the doctor knife 10 and the backing roll 102. The coating liquid is applied. In this case, it is assumed that bending occurs in the outer cylinder 12 of the doctor knife 10 due to this coating pressure, the center of the outer cylinder 12 is depressed, and the inner cylinder 14 comes close to the state shown in FIG. 7.

The measurement of the bending amount is performed by the gap sensor 48. That is, when the dimension measured by the gap sensor 48 becomes smaller than the set value, the inner cylinder 14
It is determined that the gap 16 between the cylinder and the outer cylinder 12 has been reduced and bending has occurred, and this signal is output to the control device 52.

The controller 52 rotates the motor 36 in response to a signal from the gap sensor 48, moves the worm 30 downward in FIG. 1, and adjusts the bending amount. In this case, the pressing member 42 presses the inner peripheral wall of the outer cylinder 12 downward. However, the pressing member 42 has a central point Is not pressed but two points are pressed, so that the bending amount can be adjusted evenly.

In the outer cylinder 12 pressed downward by the pressing member 42, the connecting ring 28 is curved, and the entire outer cylinder 12 bends downward. Thereby, the bending amount can be adjusted.

When the doctor knife 10 is used by rotating it by 180 °, the worm 30 shown in FIG.
Is moved in the opposite direction, the bending amount of the doctor knife 10 when rotated can be adjusted.

Whether or not the bending amount has been adjusted is determined by a signal from the gap sensor 48, and feedback control is performed.

In the doctor knife 10 described above, the motor 36 is provided inside the inner cylinder 14 and the gap sensor 4
8 constantly monitors the gap 16 between the outer cylinder 12 and the inner cylinder 14 to monitor the bending amount.
While driving 0, the bending amount can be adjusted in real time. Furthermore, since the bending amount changes depending on the traveling speed of the web W, the bending amount may be adjusted according to the traveling speed of the web W.

Further, since the inner peripheral wall of the outer cylinder 12 is pressed by the worm 30 via the pressing member 42, there is no cushioning property unlike the pressure type doctor knife. Therefore, the coating pressure can be made uniform.

In the above embodiment, the dam type coating device 1
However, the application of the doctor knife of the present invention is not limited to this, and a coating apparatus having another structure may be used. Further, the doctor knife is not limited to the comma type, but may be a roll type.

Further, in the above embodiment, the outer cylinder 12 and the inner cylinder 1
The outer cylinder 12 and the inner cylinder 14 are connected by the connection ring 28 in order to allow the movement between the outer cylinder 12 and the inner cylinder 14, but a spun ring 54 is provided between the outer cylinder 12 and the inner cylinder 14 as shown in FIG. Then, both movements may be allowed.

[0036]

As described above, according to the doctor knife in the web coating apparatus of the present invention, the bending amount of the doctor knife can be adjusted by moving the worm in the radial direction by the motor, so that the operation of the coating apparatus is stopped. The bending amount can be adjusted without any need.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a doctor knife showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is an enlarged vertical sectional view of a main part of a doctor knife.

FIG. 4 is a block diagram of the present embodiment.

FIG. 5 is an enlarged longitudinal sectional view of a main part of a doctor knife according to another embodiment.

FIG. 6 is an explanatory view of a dam type coating apparatus.

FIG. 7 is a front view of the coating apparatus in a state where the doctor knife has bent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Doctor knife 12 Outer tube 14 Inner tube 16 Gap 18, 20 Shaft part 28 Connecting ring 30 Worm 32 Worm gear 34 Reduction gear 36 Motor 42 Pressing member

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor: Masanobu Matsumoto 101, Kawai-cho, Kawai-cho, Kitakatsuragi-gun, Nara 1 in Hirano Tecseed Co., Ltd. (56) References JP-A-5-305260 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05C 11/04 B05C 3/18 B05C 1/02-1 / 16

Claims (1)

(57) [Claims] 1. A doctor knife for applying a coating liquid to a web, wherein the doctor knife is formed in a tubular shape, a worm is arranged radially inside a center of the doctor knife, and a motor is provided inside the doctor knife. A worm gear for moving the worm in the radial direction is provided on the rotating shaft of the motor, and the motor is used to move the worm in the radial direction so that the tip of the worm is pressed against the inner peripheral wall of the cylindrical doctor knife to expand the worm. A doctor knife in a web coating device, wherein a bending amount of the doctor knife is adjusted.