Three point thermistor temperature set up
AssigneeXerox Corporation
InventorMark S. Amico
Life of this patent
Estimating the term…
Abstract
Thermistors are calibrated by taking three thermistor resistance measurements at various temperatures. The resistance values are converted or transferred to Analog to Digital (A/D) bits or bit values which the machine's microprocessor can relate to temperature. The three values are utilized for constructing a calibration curve in the microprocessor for a specific thermistor bead. Use of the curve allows for mathematical interpolation by the microprocessor between calibration points, providing a wider and more accurate range to set the fuser roll temperatures. This increased accuracy over a wider range than before allows the sensor to become a common part for a family of products which may require different standby and runtime temperatures.
Claims18
A method of controlling the surface temperature of a heated fuser member having a heater structure operatively supported internally thereof, said method including the steps of:
- supporting a heated fuser member in pressure engagement with a pressure roller for fusing toner images
- heating said heated fuser member using a heater structure supported internally thereof;
- supporting at least one thermistor in temperature sensing relationship with said heated fuser member;
- establishing calibration bit values at three different temperatures for said at least one thermistor;
- storing said calibration bit values in non-volatile memory
- storing standby and runtime bit values in non-volatile memory
- using said bit values and standby and runtime bit values for calculating said runtime and standby target values for said at least one thermistor;
- storing said target values in non-volatile memory;
- and
- utilizing said target values for controlling the operating characteristics of said heat structure.
Heat and pressure fuser apparatus comprising:
- a fuser roll;
- a heating structure disposed internally of said fuser roll for elevating the surface temperature of said fuser roll to a fusing temperature;
- a pressure roll cooperating with said fuser roll to form a nip through which copy substrates carrying toner images pass with said toner images contacting said fuser roll, said rolls having inboard and outboard ends;
- a thermistor supported in temperature sensing relationship with said heated fuser member;
- means for establishing calibration bit values at three different temperatures for said thermistor;
- means for storing said calibration bit values in non-volatile memory
- means for storing standby and runtime bit values in non-volatile memory
- means stored in memory for calculating runtime and standby target values for each of said thermistors;
- means for storing said target values in non-volatile memory;
- and
- means for utilizing said target values for controlling the operating characteristics of said heat structure.
Dependencies are inferred from the claim text.