Web registration system and method
AssigneeRo-An Industries Corporation
InventorPeter Terranova
Life of this patent
Estimating the term…
Abstract
A system and method in the manufacture of plastic bags for accurately registering a web having graphic material printed repetitively thereon with respect to a transverse cutting and sealing device comprise detecting the passage of an eyemark printed on the web by a certain location at an initial part of a web index, calculating the initial length travelled by the web from the start of the web index to the detection of the eyemark, and then adjusting a predetermined draw length of the web based upon that calculated initial length.
Claims32
In a plastic bag making machine for making plastic bags from an elongate web of plastic material having a series of regularly spaced eyemarks printed thereon, the improvement comprising:
- draw roll means for intermittently advancing the web over respective draw lengths;
- optical scanner means for detecting the passage of an eyemark by a certain location at an initial part of an ongoing web index;
- means for calculating a predetermined draw length D prior to upcoming web indexes, said means for calculating said predetermined draw length D calculating the same in accordance with the formula,
- D=NL-K.multidot.W,
- where D is the predetermined draw length, NL is the nominal bag length equal to the distance between adjacent eyemarks, W is the length of a registration window in which an eyemark will normally be detected by said optical sensor means at said initial part of said ongoing web index, and K is a constant;
- means for calculating during said ongoing web index an initial length E, if any, travelled by the web from the beginning of said ongoing web index to the detection of the passage of an eyemark;
- and
- means for adjusting said predetermined draw length D of said ongoing web index based upon said initial length E.
A method for facilitating the registration of a cutting and sealing bar with non-printed areas of a plastic web situated between repetitively printed graphic fields comprising the steps of:
- calculating a predetermined draw length D prior to upcoming web indexes in accordance with the formula D=NL-KW, where D is the predetermined draw length, NL is the nominal bag length equal to the distance between adjacent eyemarks, W is the length of a registration window in which an eyemark will normally be detected, and K is a constant;
- detecting the passage of an eyemark by a certain location at an initial part of an ongoing web index;
- calculating during that web index an initial length E, if any, travelled by the web from the beginning of an ongoing web index to the detection of the passage of an eyemark;
- and
- adjusting the predetermined draw length D of the ongoing web index based upon the initial length E.
In a plastic bag making machine for making plastic bags from an elongate web of plastic material having a series of regularly spaced eyemarks printed thereon, the improvement comprising:
- draw roll means for intermittently advancing the web over respective draw lengths;
- means for calculating a predetermined draw length D prior to upcoming web indexes;
- optical scanner means for detecting the passage of an eyemark by a certain location at an initial part of an ongoing web index;
- means for calculating during said ongoing web index an initial length E, if any, travelled by the web from the beginning of said ongoing web index to the detection of the passage of an eyemark;
- and
- means for determining the draw length of said ongoing web index in which said initial length E is calculated prior to the passage of a subsequent eyemark by adjusting said predetermined draw length D based upon said initial length E.
A method for facilitating the registration of a cutting and sealing bar with non-printed areas of a plastic web situated between repetitively printed graphic fields, comprising the steps of:
- calculating a predetermined draw length D prior to upcoming web indexes;
- detecting the passage of an eyemark by a certain location at an initial part of an ongoing web index;
- calculating during that web index an initial length E, if any, travelled by the web from the beginning of an ongoing web index to the detection of the passage of an eyemark;
- and
- determining the draw length of said ongoing web index in which the initial length E was calculated prior to the passage of a subsequent eyemark by adjusting the predetermined draw length D based upon the initial length E.
Dependencies are inferred from the claim text.