Sensing probe and control for press inker embodying same

Claim 2

A sensing probe for capacitively sensing a material overlying an electrically conductive backing member, said probe comprising capacitive electrode means and coil means connected electrically to provide an L-C circuit, said capacitive electrode means coacting with the material on said backing member to vary the capacitive reactance of said L-C circuit in accordance with the dielectric properties of said material and the air gap between the probe and said material and in accordance with the spacing between the probe and said backing member, and said coil means having an impedance which is substantially unaffected by the dielectric properties of said material on the backing member and which varies with changes in the spacing between the probe and said backing member inversely with the variation of said capacitive reactance caused by such spacing changes.

Claim 3

In combination with an electrically conductive backing member for a material to be sensed, a sensing probe in spaced, confronting relationship to said backing member, said sensing probe comprising capacitive electrode means for capacitively sensing said material, and coil means connected electrically to said capacitive electrode means to provide an L-C circuit, said capacitive electrode means having a capacitance which is dependent upon said material and which varies to vary the capacitive reactance of said L-C circuit with changes in spacing between said probe and said backing member, said coil means having an impedance which is substantially unaffected by said material but which varies with changes in the spacing between the probe and said backing member inversely with the variation of the capacitive reactance of said L-C circuit caused by such spacing changes.

Claim 4

In combination with an electrically conductive backing member for a material to be sensed, a sensing probe in spaced, confronting relationship to said backing member, said sensing probe comprising capacitive electrode means for capacitively sensing said material, and coil means connected electrically to said capacitive electrode means to provide an L-C circuit, said capacitive electrode means having a capacitance which is dependent upon said material and which varies to vary the capacitive reactance of said L-C circuit with changes in spacing between said probe and said backing member, said coil means having an impedance which is substantially unaffected by said material but which varies with changes in the spacing between the probe and said backing member inversely with the variation of the capacitive reactance of said L-C circuit caused by such spacing changes.

Claim 5

The combination of claim 2, and further comprising an oscillator having said capacitive electrode means and said coil means connected to control its oscillation frequency, and means for detecting the oscillation frequency of said oscillator as a measure of the thickness of the material sensed capacitively by said capacitive electrode means in the probe.

Claim 6

In combination with an inker for a printing press having rollers for transferring a film of ink to the press, a sensing probe having capacitive probe means for sensing the thickness of the ink film on one of said rollers and whose capacitance reactance varies with the thickness of said ink film and changes in the spacing between said probe and said roller, and means responsive to vibration between said probe and roller and whose impedance varies inversely with said capacitive reactance changes but is substantially insensitive to said ink film for substantially offsetting capacitive reactance changes caused by changes in the spacing between said probe and said roller.

Claim 7

In combination with an inker for a printing press having rollers for transferring a film of ink to the press, a sensing probe having capacitive probe means for sensing the thickness of the ink film on one of said rollers and whose capacitance reactance varies with the thickness of said ink film and changes in the spacing between said probe and said roller, and means responsive to vibration between said probe and roller and whose impedance varies inversely with said capacitive reactance changes but is substantially insensitive to said ink film for substantially offsetting capacitive reactance changes caused by changes in the spacing between said probe and said roller.

Claim 8

The combination of claim 4, and further comprising means for driving said rollers, and means for regulating the speed at which said rollers are driven in accordance with the response of said probe to the thickness of said ink film on said one roller.

Claim 9

In combination with an inker for printing press having rollers for transferring a film of ink to the press, one of said rollers being of electrically conductive material, a sensing probe having capacitive electrode means spaced from said one roller by an air gap and in confronting relationship to said ink film thereon and together with said one roller providing opposite plates of capacitor means whose capacitive reactance varies with the thickness of said ink film on said one roller and varies with the spacing between said capacitive electrode means and said one roller, said probe also having coil means in spaced, confronting relAtionship to said one roller and whose impedance is substantially unaffected by said ink film on said one roller but does vary with changes in the spacing between said coil means and said one roller inversely with the changes in the capacitive reactance of said capacitor means caused by such spacing changes.

Claim 10

In combination with an inker for printing press having rollers for transferring a film of ink to the press, one of said rollers being of electrically conductive material, a sensing probe having capacitive electrode means spaced from said one roller by an air gap and in confronting relationship to said ink film thereon and together with said one roller providing opposite plates of capacitor means whose capacitive reactance varies with the thickness of said ink film on said one roller and varies with the spacing between said capacitive electrode means and said one roller, said probe also having coil means in spaced, confronting relAtionship to said one roller and whose impedance is substantially unaffected by said ink film on said one roller but does vary with changes in the spacing between said coil means and said one roller inversely with the changes in the capacitive reactance of said capacitor means caused by such spacing changes.

Claim 11

The combination of claim 6, wherein said capacitor means and said coil means are connected electrically to provide an L-C circuit, and further comprising means for responding to impedance changes in said L-C circuit as a measure of the thickness of said ink film on said one roller.

Claim 12

The combination of claim 7, wherein said last-mentioned means comprises an oscillator whose oscillation frequency is controlled by said L-C circuit, and means for producing a control signal whose magnitude is determined by said oscillation frequency.

Claim 13

The combination of claim 6, and further comprising drive means for driving said inker, and means for regulating the speed of said drive means in accordance with the response of said probe to the thickness of said ink film on said one roller.

Claim 16

In a system as defined in claim 10 wherein said compensating means provides a compensating reactance.

Claim 17

In a system as defined in claim 11 wherein said compensating means provides a compensating inductive reactance.

Claim 18

In a system as defined in claim 12 further comprising a means for selectively adjusting the spacing between the electrode and said means for providing the inductive reactance, said compensating means comprising a coil.