(19)
(11) EP 2 026 139 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
10.09.2014 Bulletin 2014/37

(43) Date of publication A2:
18.02.2009 Bulletin 2009/08

(21) Application number: 08251756.6

(22) Date of filing: 20.05.2008
(51) International Patent Classification (IPC): 
G03G 15/00(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR
Designated Extension States:
AL BA MK RS

(30) Priority: 25.05.2007 JP 2007139084
06.03.2008 JP 2008056437

(71) Applicant: Ricoh Company, Ltd.
Tokyo 143-8555 (JP)

(72) Inventors:
  • Andoh, Toshiyuki, c/o Ricoh Company Limited
    Tokyo 143-8555 (JP)
  • Matsuda, Hiromichi, c/o Ricoh Company Ltd.
    Kanagawa 243-0460 (JP)
  • Hirose, Yuichi, c/o Ricoh Company Limited
    Tokyo 143-8555 (JP)
  • Tao, Satoru, c/o Ricoh Printing Systems Ltd.
    Hitachinaka-City, Ibaraki-Pref. 312-8502 (JP)
  • Masuda, Noritaka, c/o Ricoh Printing Systems Ltd.
    Hitachinaka-City, Ibaraki-Pref. 312-8502 (JP)
  • Uozaki, Yuji, c/o Ricoh Printing Systems Ltd.
    Hitachinaka-City, Ibaraki-Pref. 312-8502 (JP)

(74) Representative: Leeming, John Gerard 
J A Kemp 14 South Square Gray's Inn
London WC1R 5JJ
London WC1R 5JJ (GB)

   


(54) Belt-conveyance control device, image forming apparatus, belt-conveyance control method, and computer program product


(57) A belt-conveyance control device includes a belt (30) that is supported by a drive roller (31) and a driven roller (32), a pulse motor (11) that drives the drive roller (31), and a first encoder (18) that is attached to the driven roller (32) to detect a displacement of the belt (30). The belt-conveyance control device controls a conveying speed of the belt (30). The belt-conveyance control device further includes a control unit that calculates a difference between the displacement detected by the first encoder (18) and a predetermined target value, calculates a pulse frequency of a driving pulse signal for driving the pulse motor (11) based on a feedback control based on the difference and a feed-forward control based on a reference driving pulse frequency, sets a control range of the feedback control to be equal to or smaller than a frequency of one rotation of the driven roller (32), and controls driving of the pulse motor (11) such that the belt (30) moves at a constant speed.







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