JP4193273B2 - Doctor device in paper calendar device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for abutting and pressing a doctor blade on a resin roll surface in a paper calendar processing apparatus.
[0002]
[Prior art]
Paper used for printing such as newspaper and information paper is subjected to a calendar process for smoothing the surface in order to improve printability. The calendar processing apparatus generally employs a method in which a large linear pressure is instantaneously applied to the paper by passing the paper through a nip portion composed of a pair of rolls. There are several types of calenders depending on the roll configuration, but one roll is a metal roll and the other roll is a resin roll having a surface coated with a synthetic resin. The soft nip calender device is a surface treatment method for smoothing a paper surface by heating a metal roll and pressing the paper instantaneously at high pressure on the surface of the heated metal roll.
[0003]
As described above, the soft nip calender device forms a nip with a heated metal roll and a resin roll. The higher the temperature of the metal roll, the greater the calendar effect, but the heat of the metal roll is directly transmitted to the resin roll through the paper or at both ends of the roll not in contact with the paper. Therefore, the metal roll cannot be heated to such a high temperature that the resin roll surface is equal to or higher than the heat resistant temperature. Although depending on the resin that coats the roll surface, when the temperature of the resin roll surface is 90 ° C. or higher, the life of the resin roll is remarkably shortened.
[0004]
When the calendering is performed for a long time, additives such as fibers and sizing agents, pigments, and the like, which are paper components, adhere to the roll surface, and the roll surface is contaminated. If these contaminants are not removed, the contaminants may adhere to the paper surface, cause a concave mark on the paper surface, or cause a hole in the paper surface. The temperature rises automatically, causing troubles such as breaking the part. Therefore, the doctor blade is brought into contact with the roll surface, and the contaminants are always scraped off and removed.
[0005]
[Problems to be solved by the invention]
The purpose of the doctor blade is to remove contaminants on the roll surface, so that the tip that contacts the roll surface has a sharp shape of about 30 to 45 degrees, and the rotation direction of the roll It abuts from the direction of the check direction, pressurizes the roll surface, and always scrapes and removes contaminants. Since the contaminants scraped off may accumulate on the surface of the doctor blade, the doctor blade is sometimes removed from the roll surface for cleaning.
[0006]
Usually, an air cylinder is used as a power means for bringing the doctor blade into contact with the resin roll surface, pressurizing the roll surface, and releasing it from the resin roll surface. That is, by reciprocating the piston rod of the air cylinder, the doctor holder is rotated about the holder shaft, and the doctor blade is brought into contact with the roll surface, pressurized, and released.
[0007]
When the paper width is increased, the widths of the doctor blade and the doctor holder are increased accordingly, and the weights thereof are also increased. Therefore, naturally, the air cylinder for rotating the doctor holder also becomes large. On the other hand, the resin roll of the soft nip calender device is softened because it is heated by heat conduction from the metal roll. For this reason, when the tip of the doctor blade is brought into contact with and pressed against the resin roll surface, it is necessary to maintain the entire width at the same time and at a uniform small appropriate pressing force.
Further, if the pressure applied by the doctor blade is too large, the resin roll surface is likely to be damaged, and is easily damaged by frictional heat. Therefore, it is necessary to keep the pressure applied to the doctor blade at a small appropriate pressure, and the appropriate value is about 80 g / cm.
[0008]
However, in the conventional soft nip calender device, the power source for bringing the doctor blade into contact with the roll surface, pressurizing, and releasing depends on a single air cylinder, so pressurization is performed with a small pressure. However, it is difficult to make contact with the entire width of the resin roll surface almost simultaneously and uniformly because the operation is slow, and the doctor blade bites into the resin roll surface due to contact with one piece, etc. Problems such as hurting frequently occur.
Air cylinders that rotate the doctor holder are installed on the left and right sides of the calendar device in the width direction. Air is introduced into the left and right air cylinders from the air piping branched from the same air piping system. It has a symmetrical structure. Therefore, the doctor holder should rotate on both sides in synchronism, but if you observe in detail, the following points are not structurally symmetric and the operation is not perfectly tuned from side to side. There was found.
[0009]
That is, the doctor blade pressurizes the resin roll surface during operation and simultaneously reciprocates finely from side to side. For this reason, the sliding device that performs the left and right reciprocating motion is attached to either the left or right side, and the load applied to the bearing portion on the sliding device side is larger than the load applied to the bearing portion on the opposite side. Moreover, although the air introduced into the left and right air cylinders is small, there is a pressure difference that disturbs the left and right balance. Therefore, due to these reasons, either the left or right of the doctor holder is rotated first, or the one that was leading is overtaken by the other after a few seconds, etc. It has been observed that a whirling movement occurs. Due to this, the touch position of the doctor blade is not uniform over the entire width, and further, the wavy phenomenon in the width direction of the blade is added to the blade, causing the blade to bouncing and causing a small scratch on the resin roll surface. It seems that the doctor blade bites into the resin roll surface.
[0010]
[Means for Solving the Problems]
Based on the above observation, the present invention has solved the above-mentioned problems in the prior art calendar apparatus by the apparatus and method described below. That is, as a power source for causing the doctor blade to approach, abut, press, and detach from the resin roll surface, the conventional technology uses a single air cylinder, whereas in the present invention, the piston rods protrude in opposite directions. Two air cylinders in which two air cylinders in the direction are connected in series are used. Then, use the first air cylinder as the power source until the tip of the doctor blade approaches the resin roll surface to a predetermined position, then switch the power source to the second air cylinder, Move and pressurize the resin roll surface with a small pressure.
[0011]
FIG. 1 shows an embodiment of a doctor blade device of a calendar device according to the present invention. In the figure, 1 is a resin roll, 2 is a doctor blade, 3 is a doctor holder, and 4 is an air cylinder. The doctor holder 3 is held rotatably about a rotation axis parallel to the rotation axis of the resin roll 1. Reference numeral 6 denotes a fixed end of a piston rod of the air cylinder, which is fixed at an appropriate position of the main body of the calendar device. The double air cylinder 4 includes a first air cylinder 4a and a second air cylinder 4b.
[0012]
In the present invention, in the two air cylinders, the head caps are connected or integrated, or the cylinder tube is integrated. Accordingly, both air cylinders reciprocate in the same direction, but the protruding directions of the piston rods are opposite to each other. The tip end portion of the piston rod of the first air cylinder is rotatably fixed to an appropriate location of the calender device body. And the edge part of the piston rod of a 2nd air cylinder is being rotatably fixed to the appropriate location of a doctor holder.
[0013]
Using this device, when the tip of the doctor blade is brought into contact with the resin roll surface and pressurized, air is first introduced into the first air cylinder, and the doctor blade is moved to a predetermined position, that is, the resin roll surface. A small gap is left between them, approaching the closest distance just before contact, and then using the second air cylinder, the tip of the doctor blade is brought into contact with the resin roll surface and pressurized with a predetermined pressure. . Normally, in a calendar device with a wide paper width, one air cylinder is installed on each of the left and right sides in the width direction as a power source for rotating the doctor holder. Therefore, the piston rods of the left and right first air cylinders are both dimensioned so that the tip of the doctor blade reaches the closest distance to the resin roll surface at the stroke end, that is, at the position where the protruding length of the piston rod is maximum. Alternatively, the attachment position of the doctor blade on the doctor holder is adjusted as described above. And when the front-end | tip part of a doctor blade reaches | attains the close distance of the resin roll surface, the 2nd air cylinder is operated simultaneously or with a suitable time interval. Adjustment of the timing for operating the second air cylinder subsequent to the first air cylinder can be performed using a known electric interlock mechanism such as attaching an auto switch or the like to the air cylinder.
[0014]
In addition, since the pressure on the resin roll surface normally uses the elasticity of the doctor blade, the cylinder stroke of the second air cylinder remains so that the doctor blade remains in contact with the resin roll surface. A design dimension may be set, and the doctor blade may be bent and deformed using the remaining cylinder stroke, and pressure may be applied with a return resistance against the bending deformation of the doctor blade. Then, when the piston of the second air cylinder reaches the stroke end, the dimensions are designed so that the applied pressure of the doctor blade becomes a desired value, or the doctor blade is configured to be adjustable.
[0015]
Even if the movements of the left and right sides do not synchronize due to the difference in load, air pressure, etc. on the left and right sides of the doctor holder in the process until the first air cylinder operates and reaches the stroke end, the stroke end When the stop is stopped, the tip of the doctor blade is designed to leave a slight gap with the resin roll surface over the entire width and to be uniform over the entire width. The operation of the air cylinder 2 starts from the position where the uniform and slight gap is left. Therefore, since the rotation angle of the second air cylinder until the tip of the doctor blade comes into contact with the resin roll surface is very small, the full width can be obtained only if the air cylinders on both the left and right sides start operating simultaneously. It is possible to make contact at the same time and with a uniform applied pressure.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the method of using the first air cylinder to bring the tip of the doctor blade closer to the closest distance of the resin roll surface and then contacting the resin roll surface with the second air cylinder has been described. As for the operation to move the doctor blade close to the distance of the resin roll surface and to remove it, the faster one naturally requires less operation loss time. The first air cylinder preferably uses a larger output that operates faster than the second air cylinder.
[0017]
Since the second air cylinder needs to pressurize the tip of the doctor blade to the resin roll surface with a small appropriate pressure, it is naturally preferable to use one having a smaller output than the first air cylinder. If the output of the first air cylinder is lower than the output of the second air cylinder, the first air cylinder will affect the air pressure of the second air cylinder when pressurizing with the second air cylinder. Since the piston rod moves from the stroke end position of the stop position, there is a drawback that it is difficult to control the pressure applied to the resin roll surface by the second air cylinder. Therefore, it is preferable that at least the output of the first air cylinder is larger than the output of the second air cylinder. In general, it is common to design the effective cross-sectional areas of the cylinder tubes of the two air cylinders to be equal. In such a case, the first air cylinder has a higher capacity than the second air cylinder. High pressure air will be introduced.
[0018]
Note that when the tip of the doctor blade is detached from the resin roll surface and retracted, there is almost no problem such as the tip of the doctor blade biting into the resin roll surface, so the second air cylinder or the first air cylinder Either of these may be used first, or both the second and first air cylinders may be used simultaneously. Further, only the first air cylinder may be used.
[0019]
As described above, the present invention uses the first air cylinder until the tip of the doctor blade is brought close to a predetermined close distance leaving a slight gap with the resin roll surface. The second air cylinder is used when the front end is brought into contact with the resin roll surface and further pressurized with a predetermined pressure. In FIG. 1, the first air cylinder is arranged on the fixed end side and the second air cylinder is arranged on the doctor holder side. The arrangement is arranged such that the second air cylinder is arranged on the fixed end side and the second air cylinder is arranged on the doctor holder side. It may be replaced with the first air cylinder.
[0020]
In the embodiment, both the first air cylinder and the second air cylinder are supplied with air manually or by an electromagnetic switching valve, and alternately flow into the cylinder chamber on the piston side and the piston rod side. As long as the weight of the doctor holder is sufficiently heavy and the doctor blade is designed to rotate in such a direction that the doctor blade can be detached from the resin roll surface, the ventilation of both cylinders may be only on the piston side of the cylinder chamber. However, since it is better to disengage as soon as possible, it is preferable to use a cylinder that can be introduced from both the piston side and the piston rod side of the cylinder chamber as shown in FIG.
[0021]
In the implementation, the timing of switching from the first air cylinder to the second air cylinder needs to be performed simultaneously or by setting an appropriate time interval. It is also necessary to prevent the second air cylinder from operating before the tip portion approaches the closest distance of the resin roll surface. Although this can be manually operated, it is desirable to provide an electrical interlock mechanism in order to prevent erroneous operation.
[0022]
【Example】
FIG. 1 is a cross-sectional view of a calendar apparatus according to an embodiment of the present invention, and FIG. 2 is an air system diagram for operating the air cylinder of FIG. 4a is a high-pressure air cylinder, 4b is a low-pressure air cylinder, and the tip of the piston rod of the high-pressure air cylinder is rotatably fixed with an appropriate portion of the calendar device body as a fixed end. The doctor holder is pivotally mounted about an axis parallel to the rotation axis of the resin roll, and the tip end of the piston rod of the low-pressure air cylinder 4b is pivotally fixed to an appropriate position of the doctor holder. . Therefore, when air is introduced into the cylinder chamber on the piston side of the high-pressure air cylinder 4a or the low-pressure air cylinder 4b, the distal end portion of the doctor blade rotates in a direction approaching the resin roll surface.
[0023]
The operating status of the above apparatus will be described below. For cleaning or the like, the doctor blade is detached from the resin roll surface, that is, the low-pressure air cylinder 4b and the piston rod of the high-pressure air cylinder 4a are accommodated in the respective cylinder chambers, or partially long as shown in FIG. In order to abut the doctor blade against the resin roll surface and pressurize it from the state where the container is stored, first, the electromagnetic or manual switching valve A is switched, and the high pressure air cylinder 4a in the direction of the arrow (1) in the figure. Ventilate the air.
[0024]
When high pressure air is introduced into the piston side of the cylinder chamber of the high pressure air cylinder 4a, the air in the cylinder chamber on the piston rod side is exhausted in the direction of arrow (3), and the piston rod moves to the left. Approach the resin roll surface. When the piston rod of the high-pressure air cylinder 4a reaches the stroke end, the design dimensions are determined in advance so that the tip of the doctor blade approaches the closest distance of the resin roll surface. Stop at a close distance on the resin roll surface.
[0025]
Next, when the electromagnetic or manual switching valve B is switched and low pressure air is vented in the direction of the arrow (2), the air is discharged from the piston rod side in the direction of the arrow (4), and the low pressure air is discharged. The piston rod of the cylinder 4b moves to the right, the doctor blade comes into contact with the resin roll surface, and pressurizes the resin roll surface while gradually increasing the pressure. When the piston rod of the low-pressure air cylinder 4b reaches the stroke end, the dimensions are designed or adjusted so that a desired pressure is obtained.
[0026]
When the tip of the doctor blade is detached from the resin roll surface, the above-described procedure may be reversed. However, when detaching, the tip of the doctor blade does not bite into the resin roll surface even if it is released at a stretch. Since there is little danger, switch the switching valves A and B of both the high pressure air cylinder and the low pressure air cylinder at the same time, and introduce air to the piston rod side of both air cylinders from the direction of arrows (5) and (6). It is desirable to let them leave at once.
[0027]
【The invention's effect】
By the apparatus of the present invention, the first air cylinder is actuated to bring the tip of the doctor blade closer to and stopped at the closest distance of the resin roll surface, and then the second air cylinder is actuated to actuate the tip of the doctor blade. The part is brought into contact with the resin roll surface. Even if the movements of the left and right sides do not synchronize due to the difference in load, air pressure, etc. on the left and right sides of the doctor holder in the process until the first air cylinder is activated and reaches the stroke end, the stroke end When the second air is stopped, the tip of the doctor blade has a slight gap with the resin roll surface over the entire width, and the gap is designed uniformly over the entire width. The cylinder starts to operate from the position where the uniform and slight gap is left. Therefore, since the rotation angle of the second air cylinder until the tip of the doctor blade comes into contact with the resin roll surface is very small, the full width can be obtained only if the air cylinders on both the left and right sides start operating simultaneously. It is possible to make contact at the same time with a uniform applied pressure, and to prevent the doctor blade from biting into the resin roll surface.
[0028]
In addition, the first air cylinder used for moving the doctor blade close to the resin roll surface and desorbing from the resin roll surface can be performed mainly by a high-pressure air cylinder, so that the operation is quick and the operating time is lost. Less. On the other hand, the second air cylinder used when the doctor blade abuts on the surface of the resin roll and pressurizes does not require a large output, so that a low-pressure air cylinder with excellent output accuracy can be used. Uniform pressure can be applied to the surface with the minimum necessary.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of the apparatus of the present invention. FIG. 2 is an air system diagram of the apparatus of the present invention.
DESCRIPTION OF SYMBOLS 1 Resin roll 2 Doctor blade 3 Doctor holder 4a 1st air cylinder 4b 2nd air cylinder 5 Rotating shaft 6 of a doctor holder Fixed end A Switching valve B Switching valve Ea High pressure air Eb Low pressure air

Claims (5)

A device that abuts and presses a doctor blade against a resin roll surface of a paper calendar device that forms a nip with a metal roll and a resin roll,
1. The doctor blade is detachably attached to a doctor holder that can rotate around an axis parallel to the rotation axis of the resin roll.
2. The doctor holder is rotated by the protrusion and retraction of the piston rod of the two air cylinders in which the first air cylinder and the second air cylinder in which the piston rods protrude in opposite directions are connected in series. The end of the piston rod of the first air cylinder is pivotally fixed to an appropriate location on the calendar device body,
3. The end of the piston rod of the second air cylinder is pivotally fixed to an appropriate position on the doctor holder so that the doctor blade in the paper calendering device is in contact with the surface of the resin roll. Device to press. 2. The doctor blade of the paper calender device according to claim 1, wherein the output of the first air cylinder is equal to or greater than the output of the second air cylinder. A device that contacts and pressurizes the surface. The doctor blade in the paper calender device according to claim 1 or 2, wherein the cylinder tube of the first air cylinder and the cylinder tube of the second air cylinder have an integral structure. A device that contacts and pressurizes. Using the apparatus according to claims 1 to 3, air is introduced into the first air cylinder, the piston rod is projected to the stroke end, and the doctor blade is brought close to the resin roll surface, and then, A method in which air is introduced into the second air cylinder, and the doctor blade is brought into contact with the resin roll surface and pressurized. Using the apparatus according to claims 1 to 3, air is introduced into the second air cylinder, the piston rod is protruded to the stroke end, and the doctor blade is brought close to the resin roll surface, A method in which air is introduced into the first air cylinder, the doctor blade is brought into contact with the surface of the resin roll and pressurized.

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