System for optimizing a regeneration schedule for a contact cleaning roller
A system for optimization of a regeneration schedule for a contact cleaning roller (CCR) used to remove particles from a substrate surface by being rolled along the substrate surface. In rolling along the surface, the CCR leaves a residual static charge. The level of leaving charge is sensed by a fieldmeter. When a CCR is first placed into service against a substrate, the leaving charge level is greater than the entering static charge level on the substrate ahead of the CCR. The entering charge is sensed by another fieldmeter, and the charge differential is determined and monitored. As the CCR becomes progressively loaded with particles during service, the leaving charge progressively diminishes. Thus the charge differential indicates inversely the particle loading of the CCR such that a charge differential limit can be set, below which the roller is removed from service and renewed by cleaning.
1 . A system for optimization of a regeneration schedule for a contact cleaning roller used to remove particles from a substrate surface by being rolled along the substrate surface, comprising:
a) a static charge detection means disposed adjacent said substrate for determining an electrostatic charge level thereupon at a location after said substrate has made contact with said contact cleaning roller;
b) means for monitoring said electrostatic charge level during use of said contact cleaning roller on said substrate surface;
c) means for comparing said monitored electrostatic charge level to a predetermined action limit value; and
d) means for causing an alarm signal when said monitored electrostatic charge level reaches a specific relationship to said predetermined action limit value.
2 . A system in accordance with claim 1 wherein said specific relationship is a maximum allowable difference between said monitored electrostatic charge level and a value selected from the group consisting of a value of an initial electrostatic charge level and a predetermined average starting value for an electrostatic charge level.
3 . A system in accordance with claim 2 wherein said specific relationship is a zero difference between said monitored electrostatic charge level and a predetermined average minimum allowable value.
4 . A system in accordance with claim 1 comprising the further step of removing said contact cleaning roller from service in response to said alarm signal.
5 . A system in accordance with claim 2 wherein said charge detection means is a first charge detection means, and wherein said electrostatic charge level is a first electrostatic charge level, and wherein said location is a first location, comprising:
a) a second charge detection means disposed adjacent said substrate for determining a second electrostatic charge level at a second location before said substrate has made contact with said contact cleaning roller;
b) means for monitoring said second electrostatic charge level during use of said contact cleaning roller on said substrate surface; and
c) means for determining a difference between said first electrostatic charge level and said second electrostatic charge level, wherein said second electrostatic charge level defines said initial electrostatic charge level.
5 . A system in accordance with claim 4 comprising the further step of removing said contact cleaning roller from service in response to said alarm signal.
6 . A method for optimization of a regeneration schedule for a contact cleaning roller used to remove particles from a substrate surface by being rolled along the substrate surface, comprising the steps of:
a) determining an electrostatic charge level at a location after said substrate has made contact with said contact cleaning roller;
b) monitoring said electrostatic charge level during use of said contact cleaning roller on said substrate surface;
c) comparing said monitored electrostatic charge level to a predetermined action limit value; and
d) causing an alarm signal when said monitored electrostatic charge level reaches a specific relationship to said predetermined action limit value.