Test to measure curling tendency of paper in laser printers
AssigneeInternational Paper Company
InventorsKapil M Singh, Williams Shields, Frederick Karsa
Life of this patent
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Abstract
The invention provides an apparatus and method for testing the tendency of a paper to curl. The paper is cut from a paper making machine and rapidly humidified to standard TAPPI conditions, and is thereafter run through an apparatus having a substantially vertically oriented nip. The paper is measured for curl, all data are tabulated and fed back into a data acquisition or paper machine control system.
Claims18
A method for measuring the tendency of a paper to achieve simplex curl, comprising
- moving a paper sample from a paper making machine through a substantially vertical nip positioned such that the paper sample exits from the substantially vertical nip in a substantially vertical orientation,
- measuring the total curl of the paper sample as or after the paper sample exits the substantially vertical nip, and
- tabulating corrective data to correct the tendency of a non-sample paper to curl in the paper making machine based.
An apparatus for performing a method for measuring the tendency of a paper to achieve simplex curl, the method comprising moving a paper sample from a paper making machine through a substantially vertical nip positioned such that the paper sample exits from the substantially vertical nip in a substantially vertical orientation and predicting the tendency of a paper to curl with a regression analysis equation that accounts for the moisture content of the paper sample and the total curl of the paper sample, the apparatus comprising
- a rotatable first roller, wherein the first roller is rotatable around a first substantially vertical axis in a substantially vertical plane;
- a rotatable second roller, wherein the second roller is rotatable around a second substantially vertical axis in the substantially vertical plane, the first substantially vertical axis parallel to the second substantially vertical axis, and the first and second rollers rotatable in opposing directions;
- a substantially vertical nip point between the first roller and the second roller such that a paper or paperboard can pass through the substantially vertical nip point;
- and
- a means for predicting tendency of a paper to simplex curl with a regression analysis equation that accounts for the moisture content of the paper sample and the total curl of the paper sample.
Dependencies are inferred from the claim text.