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IMAGE FORMING APPARATUS

  • US 20120148273A1
  • Filed: 12/01/2011
  • Published: 06/14/2012
  • Est. Priority Date: 12/08/2010
  • Status: Active Grant
First Claim
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1. An image forming apparatus comprising:

  • an image forming unit configured to form an image on a recording sheet; and

    a fixing unit comprising;

    an endless belt;

    a heater including a first resistance heating element and a second resistance heating element, the first and second resistance heating elements formed on a substrate and being in contact with an inner surface of the endless belt;

    a nip forming element that forms, together with the heater via the endless belt, a fixing nip for nipping and conveying a recording sheet having an image formed thereon, anda temperature detection unit that detects a temperature of the heater,the fixing unit capable of switching between a first operation mode in which the first resistance heating element and the second resistance heating element are connected in series and a second operation mode in which the first resistance heating element and the second resistance heating element are connected in parallel,wherein the image forming apparatus further comprises a current detection unit disposed in either a first conduction path for supplying electric power to the first resistance heating element or a second conduction path for supplying electric power to the second resistance heating element,and wherein if a temperature increase rate detected by the temperature detection unit is less than a threshold rate, although a current detected by the current detection unit is greater than a threshold current, a notification of a failure is issued or a driving operation of the apparatus is stopped.

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