Method and apparatus for checking the wrapping state of a roll

Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Mechanical measurement system

Reexamination Certificate

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Details

C702S033000, C702S042000, C702S043000, C053S204000, C053S409000, C073S862530

Reexamination Certificate

active

06178385

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of and an apparatus for checking the wrapping state of a wrapped roll of a continuous sheet material which is rolled around a core tube and wrapped with wrapping sheet and the like.
2. Description of the Related Art
There have been known various wrapping materials and wrapping methods for wrapping a roll of sheet material. For example, in one of the known wrapping methods, a leader sheet is bonded to the leading end of the rolled sheet material and an end face cover is bonded to each side edge portion of the leader sheet. The leader sheet is rolled around the sheet roll to cover the side surface of the sheet roll and then the end face covers are folded along the end faces of the roll to cover the end faces and the free edge portion of each end face cover is tucked into the end portion of the core tube. Thereafter a bushing having an outer diameter slightly smaller than the inner diameter of the core tube is press-fitted into each end of the core tube over the tucked portion of the end face cover to fix the cover on the roll.
The wrapping material comprising such a leader sheet and such end face covers is employed, for instance, to wrap a roll of photosensitive material sheet such as photographic film. The wrapping material is so arranged that the outer edges of the bonded area of the leader sheet and the end face covers run along the side edges of the sheet roll and when the leader sheet is pulled, the end face covers are easily torn along the outer edges of the bonded area, whereby the wrapped roll is opened. When the outer edges of the bonded area are not correctly positioned along the side edges of the roll and are on the side surface of the roll, the force required to pull the leader sheet increases and in extreme cases, the end face covers cannot be torn along the outer edges of the bonded area and the leader sheet cannot be properly drawn out.
Further, when the end face covers are not sufficiently bonded to the leader sheet, or the bonded area is blemished, or folding of the end face covers is defective, light-shielding performance and/or water vapor barrier characteristics of the wrapped roll can deteriorate.
Further, when tucking of the end face covers into the core tube is defective, the bushings cannot be fit in the core tube with a sufficient force, which can result in poor light-shielding performance and/or water vapor barrier characteristics of the wrapped roll and/or bushings slipping off during transfer of the wrapped roll.
Especially when the rolled sheet material is photosensitive sheet, the performance of the sheet material deteriorates if the light-shielding performance and/or water vapor barrier characteristics of the wrapped roll are poor. For example, a roll of photosensitive sheet material wrapped in a dark room will be exposed to light as soon as it is transferred to a light room. Accordingly if a defect in wrapping state is found in a dark room, the roll must be rewrapped before transferring to a light room.
However, there has not been developed an apparatus for automatically checking the wrapping state of a wrapped roll and conventionally wrapping state has been visually checked. Such a method of checking wrapping state of the rolled sheet is disadvantageous in that it takes a large amount of labor to visually check a large number of rolls and reliability of the check is poor.
SUMMARY OF THE INVENTION
In view of the foregoing observations and description, the primary object of the present invention is to provide a method of and an apparatus for automatically checking wrapping state of a wrapped roll.
Another object of the present invention is to provide a method of and an apparatus for automatically checking tucking of the end face covers into the core tube.
In accordance with a first aspect of the present invention, an image of a wrapped roll placed in a predetermined position is taken by an image taking means, information on the image of the wrapped roll is processed with respect to the density of the image and data on wrapping state of the wrapped roll is detected by a detecting means, and whether the wrapping state of the wrapped roll is satisfactory is determined on the basis of the detected data by a determining means.
In one embodiment, the wrapped roll comprises a rolled sheet material wrapped with a wrapping member including a leader sheet which is substantially equal to the rolled sheet material in width and is bonded to the leading end of the rolled sheet material and end face covers are bonded to opposite side edge portions of the leader sheet, the leader sheet being rolled around the rolled sheet material to cover the side surface of the sheet roll and the end face covers being folded along the end faces of the rolled sheet material to cover the end faces, the image taking means takes an image of the bonded area of the leader sheet and the end face covers on the side surface of the wrapped roll and a portion around the bonded area, and whether the wrapping state of the wrapped roll is satisfactory is determined on the basis of the position of the edge of the bonded area relative to the rolled sheet material and/or the state of adhesion between the leader sheet and the end face covers. The expression “the state of adhesion between the leader sheet and the end face covers” means, for instance, whether the adhesion between the leader sheet and the end face covers is good and/or whether the bonded area is blemished.
For example, the detecting means detects the position of the edge of the bonded area by binary-coding the information on the image of the bonded area of the leader sheet and the end face covers and the portion around the bonded area with respect to the density of image, adding the binary-coded image densities for the respective picture elements in the circumferential direction of the wrapped roll and comparing each of the sums obtained with a predetermined threshold value. The determining means determines the accuracy of positioning of the edge of the bonded area by comparing the position of the edge of the bonded area detected by the detecting means with a predetermined reference position.
The wrapped roll may be supported for revolution about its longitudinal axis by a rotary support means and the image taking means may be fixed in a position where it can take an image of the outer peripheral surface of the wrapped roll which is revolved by the rotary support means.
Thus in accordance with the first aspect of the present invention, the wrapping state of a wrapped roll is automatically checked according to the density of the image of the wrapped roll.
Further, when the position of the edge of the bonded area is detected by binary-coding the information on the image of the bonded area of the leader sheet and the end face covers and the portion around the bonded area with respect to the density of image, adding the binary-coded image densities for the respective picture elements in the circumferential direction of the wrapped roll and comparing each of the sums obtained with a predetermined threshold value, the position of the edge of the bonded area can be easily detected with a high accuracy, whereby accuracy of positioning of the edge of the bonded area can be surely determined.
When the wrapped roll is revolved with the image taking means fixed, the apparatus can be simpler in structure as compared to when the image taking means is moved with the wrapped roll fixed.
In accordance with a second aspect of the present invention, there is provided a method of checking the wrapping state of a wrapped roll comprising a rolled sheet material which is rolled around a cylindrical core tube, end face covers which cover opposite end faces of the rolled sheet material and part of which is tucked into the core tube, and a bushing which has an outer diameter slightly smaller than the inner diameter of the core tube and is press-fitted into each end of the core tube over the tucked portion of the end face cover. The method of the second aspect of the pre

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