The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 27, 2000
Filed:
Sep. 12, 1996
Naoto Yamaguchi, Suwa, JP;
Hiroshi Ishida, Suwa, JP;
Masayuki Kumazaki, Suwa, JP;
Kazuhiko Yamaguchi, Suwa, JP;
Yukihiro Uchiyama, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
A sheet end detector comprising a light-emitting element and a light-receiving element for detecting changes in the amount of light associated with movement of a piece of a recording medium is provided. A standard value calculator detects the difference between the sheet end detector platen voltage Vp corresponding to light reflected only from said platen and said sheet end detector paper saturation voltage Vm corresponding to light reflected only from the recording medium. The amount necessary to feed the paper for platen voltage Vp to reach paper saturation voltage Vm is a constant value, irrespective of recording medium characteristics, which is when all of the light is reflected by the recording medium and the entire end portion of a piece of a recording medium has reached a predetermined position relative to the position of the sheet end detector. A standard value is calculated by multiplying this difference by a constant coefficient C and then adding back the lesser of Vp or Vm, C being a numerical value greater than 0 and less than 1 and being an indication of the desired position of the leading edge of the recording medium. A comparator compares the standard value and a signal from the sheet end detector and determines when the signal corresponds to the standard value, which is indicative that the presence of a leading edge or trailing edge of the recording medium has reached a predetermined position.