(19)
(11) EP 0 763 784 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
04.06.1997 Bulletin 1997/23

(43) Date of publication A2:
19.03.1997 Bulletin 1997/12

(21) Application number: 96306667.5

(22) Date of filing: 13.09.1996
(51) International Patent Classification (IPC)6: G03G 15/00
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 13.09.1995 JP 260689/95
12.08.1996 JP 229335/96

(71) Applicant: SEIKO EPSON CORPORATION
Shinjuku-ku, Tokyo (JP)

(72) Inventors:
  • Yamaguchi, Naoto
    Suwa-shi, Nagano-ken (JP)
  • Ishida, Hiroshi
    Suwa-shi, Nagano-ken (JP)
  • Kumazaki, Masayuki
    Suwa-shi, Nagano-ken (JP)
  • Yamaguchi, Kazuhiko
    Suwa-shi, Nagano-ken (JP)
  • Uchiyama, Yukihiro
    Suwa-shi, Nagano-ken (JP)

(74) Representative: Sturt, Clifford Mark et al
J. MILLER & CO. 34 Bedford Row, Holborn
London WC1R 4JH
London WC1R 4JH (GB)

   


(54) Method for detecting an end portion of a recording paper in a recording apparatus and end portion detection apparatus


(57) A sheet end detector 10, made from a light-emitting element 11 and a light-receiving element 12, detecting changes in the amount of light associated with movement of a recording paper; a standard value calculation means 24, detecting an amount of difference (Vm - Vp) between said sheet end detector 10 platen voltage Vp resulting from light reflected from a sheet guide and said sheet end detector 10 paper saturation voltage Vm resulting from light reflected from a recording paper, and calculating a standard value Vs= [(Vm - Vp) x C] + Vm by multiplying by a constant coefficient C greater than 0 and less than 1; and a comparing means 25, comparing said standard value and a signal from said sheet end detector 10 and recognizing a point in time when said signal corresponds to said standard level as being indicative of the presence of a leading edge or trailing edge of a recording paper, are provided. The amount of paper feeding necessary for platen voltage Vp to reach standard value Vsa, Vsb is a constant value Nt - Ns irrespective of paper characteristics. As standard value Vs is a constant value, the point in time when this amount of light is reached is the point in time when the end portion of a recording paper has reached a constant sheet end detector relative position Nt, Nb.






Search report