Patent ID: 11934127
Assignee: OKI ELECTRIC INDUSTRY CO., LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 6:
7. A fixation device comprising:
an annular belt with an outer peripheral surface that is configured to move at a predetermined speed and including an elastic layer with a thickness of more than 300 μm; and
a counter member that is opposite the outer peripheral surface of the annular belt and forms a nip region with the annular belt,, wherein
a ratio (A/B) of a first hardness value (A) to a second hardness value (B) of the annular belt is 0.566 or more, where the first hardness value (A) is a value as measured, in hardness measurement of the outer peripheral surface using a hardness meter, at a first time point when a measurement time corresponding to a passage time has just passed since a start of the hardness measurement, and the second hardness value (B) is a value as measured, in the hardness measurement, at a second time point when the measured value of the hardness meter has just been saturated, wherein the passage time is a time it takes for a certain point of the outer peripheral surface to pass through the nip region,
a height difference of the outer peripheral surface along a circumferential direction of the annular belt at a first location in a width direction of the annular belt, which is a difference between a local maximum to a local minimum in a film thickness profile of the annular belt along the circumferential direction of the outer peripheral surface at the first location in the width direction of the annular belt, is less than 101 μm,
the nip region includes a first load region in which a first load is applied against the counter member, and a second load region in which a second load greater than the first load of the first load region is applied against the counter member, and
the annular belt is configured such that a length, in the circumferential direction of the annular belt, of a portion of the outer peripheral surface of the annular belt from the local maximum to the local minimum is shorter than a length, in the circumferential direction of the annular belt, of the first load region of the nip region.