US 9,811,033 B2
Fixing device and image forming apparatus therewith
Masafumi Miki, Osaka (JP)
Assigned to KYOCERA Document Solutions Inc., Osaka (JP)
Filed by KYOCERA Document Solutions Inc., Osaka (JP)
Filed on Oct. 7, 2016, as Appl. No. 15/288,838.
Claims priority of application No. 2015-240046 (JP), filed on Dec. 9, 2015.
Prior Publication US 2017/0168439 A1, Jun. 15, 2017
Int. Cl. G03G 15/20 (2006.01)
CPC G03G 15/2085 (2013.01) 6 Claims
OG exemplary drawing
 
1. A fixing device comprising:
a heating member;
a pressure member contacting the heating member to form a nip portion;
a pressure mechanism comprising
a pressing member holding one of the pressure member and the heating member and supported to be swingable in directions toward and away from another of the pressure member and the heating member and
a biasing member one end of which contacts the pressing member to bias the pressing member in a direction toward or away from the other of the pressure member and the heating member,
the pressure mechanism giving nip pressure to the nip portion; and
a pressure adjustment mechanism comprising an eccentric cam in which a distance from a rotation center of the eccentric cam to an outer peripheral surface of the eccentric cam varies in a circumferential direction of the eccentric cam, the pressure adjustment mechanism varying the nip pressure given to the nip portion, wherein
the pressure adjustment mechanism uses one of a small-diameter part of the outer peripheral surface of the eccentric cam and a large-diameter part of the outer peripheral surface of the eccentric cam, the distance from the rotation center of the eccentric cam to the outer peripheral surface of the eccentric cam being larger at the large-diameter part than at the small-diameter part, to allow the pressure mechanism to give the nip pressure, and uses another of the small-diameter part and the large-diameter part to allow the pressure mechanism to release the nip pressure,
when the large-diameter part of the eccentric cam is used by the pressure adjustment mechanism to allow the pressure mechanism to give or release the nip pressure, the eccentric cam constantly receives reaction force urging the eccentric cam to rotate in a direction toward the small-diameter part,
a recording medium carrying a toner image passes through the nip portion to have the toner image heated and pressed to be fixed on the recording medium, and
the eccentric cam has a curved shape in which the distance from the rotation center of the eccentric cam to the outer peripheral surface of the eccentric cam continuously increases in a whole region from the small-diameter part to the large-diameter part.