INPUT PAPER SENSOR FOR SINGLE SHEET PAPER PROCESSING EQUIPMENT
 Inventors: Richard F. Beaufort, Boise; Robin P.
Yergensen, Meridian, both of Id.
 Assignee: Hewlett-Packard Company, Palo Alto, Calif.
 Appl. No.: 381,382
 Filed: Jan. 31,1995
 Int. CI.6 G03G 21/00
 U.S. CI 355/206; 271/258.03; 355/316
 Field of Search 355/205, 206,
355/316; 271/3.15-3.17, 4.02, 4.03, 10.02-10.03, 258.03, 265.01, 258.01
 References Cited
U.S. PATENT DOCUMENTS
3,970,384 7/1976 Yamamoto et al 355/206
4,937,622 6/1990 Makiura 355/206
5,262,637 11/1993 Cumberledge et al 250/223
5,262,823 11/1993 Nakajima et al 355/205
5,365,322 11/1994 Hamada et al 355/316
FOREIGN PATENT DOCUMENTS
4-338064 11/1992 Japan .
Primary Examiner—Nestor R. Ramirez
Paper processing equipment such as a laser printer uses a plurality of sensors to detect the presence of paper in the paper path of the equipment. In order to determine the nature of malfunctions indicated by presence or absence of paper at the sensors, data from the sensors is coordinated with information concerning the timing of the data. In one embodiment, a single data signal is used to provide information that a paper supply hopper is empty and that paper is present at an output of a paper sheet pick mechanism. Advantages include simpler operation and the provision of discrete display indicia for different types of malfunctions and paper out conditions.
12 Claims, 4 Drawing Sheets