Methods and apparatus for prescribing web tracking in processing equipment
AssigneePresstek, Inc.
InventorsNandakumar Vaidyanathan, Robert Bruce Lowd
Life of this patent
Estimating the term…
Abstract
Methods and apparatus to reduce or eliminate misalignment, wrinkles, and creases in coated web product. A relationship between web outgassing pressure and surface roughness of the web and web transporting rollers is developed. This relationship allows for the control over the web outgassing pressure. The ability to adjust the web tension pressure, as well as the selection of web transporting rollers with prescribed surface characteristics, allows an operator to control the degree to which the web floats over or tracks the web transporting roller. A controller, in response to pressure and tension sensors, can also provide dynamic, closed-loop control of the entire system.
Claims33
A method for prescribing the degree to which a web floats about a web transporting roller, the web having an outgassing pressure, the method comprising the step of setting an operational web tension pressure in relation to the web outgassing pressure.
A method for prescribing the degree to which a web floats about at least one web transporting roller, the web having an outgassing pressure, the method comprising the step of selecting a configuration of the at least one web transporting roller based at least in part on an average surface roughness of the at least one web transporting roller.
A method for prescribing the degree to which a web floats about at least one web transporting roller, the web having an outgassing pressure, the method comprising the steps of:
- setting an operational web tension pressure in relation to the web outgassing pressure;
- and
- selecting a configuration of the at least one web transporting roller based at least in part on an average surface roughness of the at least one web transporting roller.
A method for selecting a web transporting roller, the web transporting roller having an actual average surface roughness, the method comprising the steps of:
- computing a web outgassing molecular density based on at least one of web geometry, web transporting roller geometry, and a maximum web tension pressure;
- computing the average surface roughness of the web transporting roller based at least in part on the web outgassing molecular density;
- and
- selecting the web transporting roller based on the actual average surface roughness in relation to the computed average surface roughness.
An apparatus for adjusting operational tension pressure of a web, comprising:
- a web transporting roller;
- a pressure sensor responsive to the ambient pressure about the web transporting roller;
- a tension sensor responsive to the tension pressure of the web;
- and
- at least one web tensioning roller adjustable in response to an output from the pressure sensor.
An apparatus for adjusting operational tension pressure of a web, comprising:
- means for measuring ambient pressure about a web transporting roller;
- means for measuring web tension pressure;
- and
- means for adjusting web tension pressure in response to the measured ambient pressure.
An article of manufacture comprising a program storage medium having computer readable program code embodied therein for prescribing the degree to which a web floats about a web transporting roller, the computer readable program code in the article of manufacture including:
- computer readable code for causing a computer to monitor a web outgassing pressure during web transporting roller operation;
- and
- computer readable code for causing a computer to adjust an operational web tension pressure in relation to the monitored web outgassing pressure, so as to prescribe the degree to which a web floats about a web transporting roller.
A program storage medium readable by a computer, tangibly embodying a program of instructions executable by the computer to perform method steps for prescribing the degree to which a web floats about a web transporting roller, the method steps comprising:
- monitoring the web outgassing pressure during web transporting roller operation;
- and
- adjusting an operational web tension pressure in relation to the monitored web outgassing pressure, so as to prescribe the degree to which a web floats about a web transporting roller.
Dependencies are inferred from the claim text.