| Number | Name | Date | Kind |
|---|---|---|---|
| 3875860 | Barber | Apr 1975 | |
| 3902716 | Lewis | Sep 1975 | |
| 4390118 | Gardner, Jr. | Jun 1983 | |
| 4632379 | Steinhilber | Dec 1986 | |
| 4671441 | Hauslaib | Jun 1987 | |
| 4690577 | Kikuchi et al. | Sep 1987 | |
| 4777729 | Hausler | Oct 1988 | |
| 4793605 | Tajima | Dec 1988 | |
| 4809969 | Bastow et al. | Mar 1989 | |
| 4925177 | Nakamura et al. | May 1990 |
| Number | Date | Country |
|---|---|---|
| 144061 | Jun 1988 | JPX |
| 271335 | Oct 1989 | JPX |
| Entry |
|---|
| Dicesare et al. "Paper Thickness Detection" Xerox Disclosure Journal, vol. 15, No. 1. Jan./Feb. 1990, pp. 57-58. |