JP2000317518A - Curl straightening method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the straightening quantity of a metal web by estimating the secular curl quantity which is secularly changed before a cut sheet is used, and determining the curl quantity during the use to be within an appropriate range to keep the curl quantity in an appropriate range when a PS film is used. SOLUTION: The curl quantity R is measured by a triangular taper scale 60 by placing a PS film 30 on a flat measuring base 40 for measurement. A coated surface 30A is directed upward, and the convex warp and the concave warp are indicated by (-) and (+), respectively. The residual stress is exerted in the PS film immediately after it is cut, an the curl quantity is changed as the time elapses. Even when the initial curl quantity is 0 mm, the curl quantity becomes -1.2 mm after two weeks, and is out of the appropriate range of -1 to +3 mm. The curl quantity after two weeks can be set to the appropriate range of -1 mm to +3 mm by adjusting the straightening quantity so that the curl quantity R immediately after the cutting is in the range of 1 to +5 mm. The convex warp of an edge portion of the PS film 30 by about -2 mm upward due to secular change is taken into consideration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for straightening a metal web as a base material of a sheet material such as a photosensitive lithographic printing plate.

[0002]

2. Description of the Related Art A photosensitive lithographic printing plate (hereinafter, referred to as "PS plate") is generally prepared by subjecting a metal web such as a coiled aluminum plate to surface treatment such as graining, anodic oxidation, and chemical conversion treatment alone or appropriately. It is manufactured by performing a combination, followed by applying and drying a photosensitive solution, and then cutting and packaging into a desired size. The PS plate is subjected to plate making processing such as image formation, development processing, gumming, and the like using the action of light or heat, and is set in a printing press to perform printing.

[0003] By the way, since the PS plate is obtained by cutting a coil-shaped metal web, a winding habit remains.
Curling called curl occurs due to stress applied when the sheet passes through a roll serving as a conveying unit. If such a bend occurs, a problem such as meandering of the PS plate occurs when the sheet is sent to a plate making machine, a developing machine, or an automatic conveyance device.

For this reason, before cutting the metal web, straightening is carried out by a roller leveler or a decurler (Japanese Patent Application No. Sho 6).
2-28343, Japanese Patent Publication No. 7-16918). However, the amount to be corrected can be adjusted by changing conditions such as the amount of pushing the metal web into the roller leveler and the amount of tilt (difference in the amount of pushing before and after the leveler device). Adjustment may be required depending on the state of the web (thickness, history, processing method) and the outer peripheral side or the core side of the coil.

On the other hand, in order to stably process a PS plate with a plate making machine or the like, it is necessary to keep the amount of curl of floating at the edge portion within a certain range.
The correction amount must be adjusted within the appropriate range of mm.

However, the PS plate immediately after the metal web has been straightened and cut into a predetermined size is subjected to residual stress, and the curl amount changes over time, which may cause the PS plate to fall out of an appropriate range. .

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above facts, and has as its object to adjust the correction amount of a metal web so that the curl amount when a PS plate is actually used falls within an appropriate range. I do.

[0008]

According to the first aspect of the present invention, the curl of the coiled metal web as the base material cut into the sheet material is corrected. Here, the correction amount of the metal web is estimated such that the curl amount over time that changes with time until the sheet material after cutting is actually used is used, and the curl amount of the sheet material during use is in an appropriate range. It is determined.

As described above, by taking into account the curl amount of the sheet material over time due to the residual stress and setting the curl correction amount of the metal web, for example, when the sheet material is used in a plate making machine or the like, the curl amount is reduced. Is within the proper range, so no problem occurs.

According to the second aspect of the present invention, the curl amount over time is considered to be constant after a predetermined period has elapsed. this is,
It has been experimentally proved that the curl due to the residual stress does not change after a predetermined period has elapsed. Therefore, the curl correction amount of the metal web can be determined with this as a target.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (Outline of cutting line) As shown in FIG.
On the upstream side of the cutting line where the (cutting device) is located,
Delivery machine 1 for delivering metal web 12 wound in a coil shape
4 are provided. The metal web 12 unwound from the feeder 14 is curled by a curl correcting device 13 described later, which is caused by curl or the like.

Next, at the feed roller 16, the interleaf paper 18 is overlapped and charged and adhered to reach the notcher 20. The notcher 20 punches out the edge or the center of the metal web 12 so that the upper trimming blade 22 and the lower trimming blade 24 of the slitter 10 can move in the width direction of the metal web 12 at the punching position. Thereby, the trimming width (width size) of the metal web 12 can be changed while continuously cutting (cutting the slip sheet and the web). If necessary, the center blade 26 slits the center of the metal web 12 to form a two-piece metal web.

In this manner, the feed length of the metal web 12 having the predetermined trimming width is detected by the length measuring device 42, and the cutter 32 moves the metal web 1 at the designated timing.
2 is cut to produce a PS plate 30 of a set size.

The PS plate 30 having the product size is sorted by the sorting device 44 into a passing product and a defective product. And
Passed products are placed on a conveyor 49 and are collected at a collecting place 46 (FIG. 1).
Although only one stacking place is shown in the figure, there are actually a plurality of stacking places). The accumulated bundle is packed in a predetermined number of units and shipped with cardboard or the like. Defective products are sent to a disposal place by a discharge conveyor 48.

Here, the curl correcting device 13 will be described.

As shown in FIG.
Is composed of a metal roller 28 disposed on the upper side and covered with urethane rubber or the like for preventing scratches, and a roller 38 disposed on the lower side. As the roller diameter, a dimension capable of correcting the curl, for example, an arbitrary diameter of φ30 to φ150 can be selected. The roller shafts of the rollers 28 and 38 are displaced along the transport direction of the metal web 12,
The curl of the metal web 12 passing between the roller and the roller 38 is corrected.

As described above, the metal web 12 is alternately entrapped and conveyed by the rollers 28 and 38, whereby the metal web 12 is deformed by repeated bending, and the internal stress caused by curling is reduced, subdivided, and flattened. Together with the curl in a predetermined direction.

Here, the bearing (not shown) supporting the roller 38 is lifted by operating the handle, and the amount of the roller 38 biting between the rollers 28 is increased, so that the curl correction amount can be increased. In addition, the correction amount can be changed by changing the amount of bite of the downstream roller gradually toward the upstream side (changing the tilt amount).

As described above, there are various correction methods, but the correction amount needs to be adjusted in consideration of the state of the metal web (thickness, history, processing method, outer peripheral side of the coil or core side). is there.

For example, when the lifting (curling amount R) of the edge of the PS plate 30 after cutting the metal web 12 by the cutter 32 is intended to be R = 2 mm, the thickness of the metal web 12 is set to 0.24 mm. Then, Roller 2
In the case of a combination of five rollers 8 and six rollers 38, the depth of the roller 38A on the upstream side is 3.5 mm, and the depth of the roller 38B on the downstream side is 1.5 mm. In addition,
It is preferable to confirm the correlation between the amount of biting of the roller 38 and the amount of curl of the PS plate 30 after cutting for each coil.

As shown in FIG. 3, a method called a decurler in which the roll pitch is widened and the amount of wrapping around the roll 51 is increased is also employed. The roll 52 is a backup roll for preventing the roll 51 from bending. These move up and down in pairs, and the correction amount can be changed by changing the wrap amount on the roll 51.

Further, the correction amount becomes constant when the roll wrap angle exceeds a certain value determined by the plate thickness, roll diameter, tension and the like. In the case of a combination of a plurality of rolls, the roll for which the correction amount is changed is determined based on the arrangement. In the example of FIG. 3, the correction amount is changed by changing the position of the third rolls 51A and 52A. In this example, four rolls for straightening are arranged in a row, but they can be used by appropriately arranging them in a web path.

When the target value of the curl amount is set as described above, the correction amount can be determined according to the state of the metal web. Note that the curl amount R shown in FIG. 4 is measured by placing the PS plate 30 on a flat measuring table 40 for measurement and measuring the triangular taper scale 60 with the application surface 30A facing upward. If it is warped up (-)
And (+) indicates that the sheet is warped downward (when the sheet is warped downward, the measurement is performed with the application surface 30A facing down).

However, the PS plate immediately after being cut is subjected to residual stress, and the amount of curl changes over time (it becomes an imaginary line). For example, as shown in FIG. If the initial curl amount is 0 mm, it becomes -1.2 mm after 2 weeks, and the appropriate range is -1 to +3 mm.
Get off. For this reason, in the present invention, the curl amount R at the time of use for two weeks or more is adjusted to -1 mm or less by adjusting the correction amount so that the curl amount R of the PS plate immediately after cutting is in the range of 1 mm to +5 mm. It can be brought to an appropriate range of +3 mm. That is, it takes into account that the edge portion of the PS plate 30 is warped upward by about −2 mm due to a change over time.

It should be noted that "after 2 weeks" is a result of an investigation that the curl amount does not change over time after that, based on the thickness and processing method of the PS plate normally produced on the line. The specific number of days varies depending on the condition of the metal web. However, this is a matter that can be dealt with by investigating each lot.

[0026]

According to the present invention, the curl amount when the sheet material is actually used falls within an appropriate range.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a cutting line in which a curl correcting method according to an embodiment is adopted.

FIG. 2 is a schematic view of a straightening device for straightening a metal web.

FIG. 3 is a schematic view showing another example of a straightening device for straightening a metal web.

FIG. 4 is an explanatory diagram showing a method for measuring the curl amount of a PS plate.

FIG. 5 is a graph showing a change in curl amount over time.

[Explanation of symbols]

 28 rollers 38 rollers

Claims (2)

[Claims] 1. A curl correction method for correcting curl of a coiled metal web as a substrate cut into a sheet material, wherein the curl amount changes with time until the sheet material after cutting is actually used. And a curling correction method for correcting the metal web so that the curling amount of the sheet material during use is within an appropriate range by taking into account the amount of curling over time. 2. The curl correction method according to claim 1, wherein the curl amount over time is regarded as constant after a predetermined period has elapsed.