Larry M Ernst
Engineers at Monroe Dr, Boulder, CO

4496829, Jan 29, 1985

Dec 10, 1982

6/448661

Arthur G. Black - Boulder CO
John H. Dodge - Thornton CO
Larry M. Ernst - Boulder CO

International Business Machines Corporation - Armonk NY

H05B 102

219497

Control system which measures overshoot or undershoot time of a controlled variable with respect to a set value and adjusts a proportional count if the overshoot or undershoot time period exceeds fixed values. The proportional count is used to control the system output in a proportional manner, such as supplying k out of every n cycles of power, where k represents the proportional count. To prevent excessively long periods of overshoot or undershoot, an overlimit detector provides adjustments of the proportional count when the overshoot or undershoot measured time exceeds an overlimit value. The control system has general applicability but is described in the temperature control of a fuser hot roll such as used in electrophotostatic copiers.

4326796, Apr 27, 1982

Dec 13, 1979

6/103143

James R. Champion - Longmont CO
Larry M. Ernst - Boulder CO
Leland W. Ford - Boulder CO
Ronald G. Velarde - Longmont CO

International Business Machines Corporation - Armonk NY

G03G 1502

355 14CH

Factors affecting copy quality are continuously adjusted during copying in accordance with the actual charge on the photoconductor relative to a fixed reference potential. The photoconductor, carried on a moving, partially exposed, constant potential conductive support, is sensed by a probe. The probe supplies a signal as a function of the potential on portions of the photoconductor and the conductive support passing by the probe. A circuit converts the probe signals into digitized values representing the current photoconductor potential relative to the support. The digitized values adjust copier parameters to compensate for deviations of photoconductor potential from predetermined desired values.

4377338, Mar 22, 1983

Aug 7, 1981

6/291136

Larry M. Ernst - Boulder CO

International Business Machines Corporation - Armonk NY

G03G 1500

355 14D

Data correlated to the light reflectance of a maximum toned area and a minimum toned area is recorded to establish standards for monitoring and controlling subsequent copier operation. A test pattern is imaged onto the photoconductor by controlled illumination levels in a series of steps with the detection of light reflectance from that test pattern being subsequently compared to establish the maximum black and maximum white criteria for storage. Light reflected from cleaned photoconductor areas and subsequently established toner patches then are used to compare against the original test pattern reflectance data. Toner replenishment, controls and machine function monitoring (e. g. : white copy background, developer operation, etc. ) are based on these recorded standards from the test pattern.

T108048, Jul 7, 1981

Jan 7, 1980

6/110262

Larry M. Ernst - Boulder CO

G03G 1500

355 14FU

In a xerographic machine having control apparatus for regulating the temperature of a toner fusing device, said control apparatus comprising: a toner fusing device having electrical heater means for elevating the temperature of at least a portion of said fusing device; first means responsive to the temperature of said fusing device for providing an electrical manifestation indicative of the temperature of said fusing device; a controllable source of electrical energy for providing a controllable number of increments of electrical energy per unit of elapsed time to said heater means of said fusing device; and microprocessor means interconnecting said first means and said controllable source of electrical energy, whereby said microprocessor means in response to the electrical manifestation indicative of the temperature of said fusing device controls the number of increments of electrical energy provided to said heater means during each unit of elapsed time.

4166690, Sep 4, 1979

Nov 2, 1977

5/847957

James L. Bacon - Boulder CO
Larry M. Ernst - Boulder CO
William G. Hauptman - Boulder CO

International Business Machines Corporation - Armonk NY

G03G 1502, H02M 3335

355 3CH

A digitally regulated power supply for the corona charging unit of an electrostatic copying machine in which a sample of the ionic current of the corona unit is utilized in conjunction with a digital regulator to regulate the power supply establishing the charge of the corona. The digital regulator in conjunction with at least one pulse width modulated power supply permits very fast rise and fall times of the power supply current. Further, between duty cycles of the machine, the digital regulator stores a representation of the correct operating point of the corona charging unit determined in the immediately prior duty cycle. In the next duty cycle, the representation is utilized by the digital regulator to initially regulate the power supply.

4183657, Jan 15, 1980

Apr 10, 1978

5/894955

Larry M. Ernst - Boulder CO
Steven D. Seigal - Boulder CO
George W. Van Cleave - Boulder CO

International Business Machines Corporation - Armonk NY

G03G 1500

355 14R

A system for checking copy quality variables within the image area of an electrophotographic machine. During a test cycle, quality is checked by producing sample test areas within the photoconductor image area ordinarily used for producing copies. Reflectance measurements are made on the sample test areas and compared to a dynamically floating reference achieved by a reflectance measurement from a cleaned portion of the photoconductor within the image area. The testing circuit is balanced so that the same reflectance voltage should be generated whether the single reflectivity-sensing device is viewing a sample test area or a cleaned reference area. The system checks for quality variables such as toner concentration, image voltage and an abnormally low reflectance photoconductor and provides a partial check on its own fault-free condition during periods when it is not in use.

4322847, Mar 30, 1982

Mar 10, 1980

6/128685

John H. Dodge - Thornton CO
Larry M. Ernst - Boulder CO

International Business Machines Corporation - Armonk NY

G01R 3128, G06F 1100

371 20

System and method for determining whether a first operation is responsive to a controller. A second operation, whose successful functioning depends on the successful functioning of the first operation and which produces a sensible result, is initiated while the first operation is inhibited by the controller. Sensing that the second operation is producing a result indicates that the first operation is not responsive to the controller. A further test is provided to determine whether the second operation is functioning properly.

4415800, Nov 15, 1983

Aug 24, 1981

6/295435

John H. Dodge - Thornton CO
Larry M. Ernst - Boulder CO

International Business Machines Corporation - Armonk NY

H05B 102

219497

Copier fuser roller temperature is monitored during the warm-up period by a series of decreasing temperature threshold levels. Each threshold level is monitored for a preselected time period and reduced for the next time period. The sampling continues until the fuser roller temperature sensed by a thermistor or the like exceeds the threshold level. At that point, the control logic for the copier is enabled for normal copying since the fuser roller temperature profile is then approaching at an adequate level for proper fusing of copy sheets. Fuser over-temperature, under-temperature and failure conditions are determinable.