(19)
(11)EP 2 420 894 A3

(12)EUROPEAN PATENT APPLICATION

(88)Date of publication A3:
21.09.2016 Bulletin 2016/38

(43)Date of publication A2:
22.02.2012 Bulletin 2012/08

(21)Application number: 11173457.0

(22)Date of filing:  11.07.2011
(51)International Patent Classification (IPC): 
G03G 15/00(2006.01)
G03G 15/01(2006.01)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME

(30)Priority: 12.07.2010 JP 2010158301

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

(72)Inventor:
  • Abe, Yasuhiro
    Tokyo 143-8555 (JP)

(74)Representative: Schwabe - Sandmair - Marx 
Patentanwälte Rechtsanwalt Partnerschaft mbB Joseph-Wild-Straße 20
81829 München
81829 München (DE)

  


(54)Image forming apparatus and method of controlling image forming apparatus


(57) A length L of the test pattern string (210) is determined so as to satisfy a condition L≤{P-(Q1+Q2)}×V, where a time Q is a total time of a time Q1 for which the test pattern string (210) is transferred from an exposure position of the test pattern string to a sensor (115a, 115b, 115c) and a time Q2 from when the test pattern string (210) is detected by the sensor (115a, 115b, 115c) until a color misregistration correction value calculated on the basis of a result of detecting is reflected in image formation; a time P is a time from a timing of starting to write the test pattern string to a timing of starting to write an image in which the correction value should be reflected; and a driving speed of a second image carrier (114) is V.







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