Patent ID: 6849130

Claim:
An apparatus for operating a fluid dispensing gun to dispense fluid at a desired location onto a substrate moving relative to the dispensing gun, the dispensing gun being operated by a gun driver and requiring a switching time to change operating states, the apparatus comprising: a first sensor for detecting a feature of the substrate as it moves relative to the fluid dispensing gun prior to the fluid dispensing gun dispensing fluid onto the substrate; a feedback device for detecting relative motion between the substrate and the fluid dispensing gun; a counter connected to said first sensor and said feedback device for measuring the relative motion between the substrate and the fluid dispensing gun in response to said first sensor detecting the feature of the substrate; a pattern store for storing data relating to a series of fluid dispensing cycles; a comparator connected to said counter and said pattern store and providing first signals to the gun driver causing the fluid dispensing gun to execute the series of dispensing cycles; a second sensor producing a sensor feedback signal representing a detected edge of dispensed fluid on the substrate; and a switching time detector connected to said feedback device, said second sensor and said comparator and measuring the switching time, said switching time detector producing a compensation signal causing the comparator to adjust an application of the first signals to the gun driver, so that the fluid dispensing gun dispenses fluid at the desired location on the substrate.