Contact-separation mechanism, fixing device, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-2020172359-A1
Application number	US-201916594772-A
Country	US
Kind code	A1
Filing date	Oct 7, 2019
Priority date	Nov 29, 2018
Publication date	Jun 4, 2020
Grant date	—

Abstract

A contact-separation mechanism includes a cam to rotate to move a contact-separation member to and from a counterpart member, a detection target to rotate together with the cam, and a detector to detect presence or absence of the detection target in a detection area of the detector, and circuitry. The cam has a reference range. The circuitry issues a rotation stop instruction of the cam after a target time elapses from passing of the reference range of the detection target through the detection area, and sets the target time based on a duration of an immediately preceding passing of the reference range through the detection area.

First claim

What is claimed is:

1 . A contact-separation mechanism comprising:
a cam configured to rotate to move a contact-separation member to and from a counterpart member; a detection target having a reference range, the detection target configured to rotate together with the cam; a detector configured to detect presence or absence of the detection target in a detection area of the detector; and circuitry configured to:
issue a rotation stop instruction of the cam after a target time elapses from passing of the reference range of the detection target through the detection area; and
set the target time based on a duration of an immediately preceding passing of the reference range through the detection area.

2 . The contact-separation mechanism according to claim 1 , further comprising a timer configured to measure the target time,
wherein the circuitry is configured to
determine, based on a timing of time measurement by the timer, a timing of the rotation stop instruction of the cam in one of moving of the contact-separation member to the counterpart member and moving of the contact-separation member from the counterpart member; and
determine, based on a detection timing of the detection target by the detector, a timing of issuance of the rotation stop instruction of the cam in the other of the moving of the contact-separation member to the counterpart member and moving of the contact-separation member from the counterpart member.

3 . The contact-separation mechanism according to claim 2 ,
wherein the number of the detector is one.

4 . The contact-separation mechanism according to claim 1 , further comprising a direct-current motor configured to drive the cam.

5 . The contact-separation mechanism according to claim 1 , further comprising a planetary gear reducer configured to transmit a driving force to the cam at a reduced speed.

6 . A fixing device comprising:
a fixing rotator; a pressure rotator pressed against the fixing rotator; and the contact-separation mechanism according to claim 1 , to move at least one of the fixing rotator and the pressure rotator closer to and from the other of the fixing rotator and the pressure rotator.

7 . An image forming apparatus comprising:
an image forming device configured to form an image; and the contact-separation mechanism according to claim 1 .

Assignees

• Ricoh Co Ltd

Inventors

• Nanno Shigeo
• Tanaka Kimihiro
• Ikeda Tamotsu
• Tomita Kenji
• Saito Osamu

Classifications

• B65H2555/25

  D.C. motors, e.g. shunt motors · CPC title

• B65H3/0676

  with two or more separator rollers in the feeding direction · CPC title

• B65H2403/51

  Cam mechanisms · CPC title

• B65H7/02

  by feelers or detectors · CPC title

• B65H29/20

  by contact with rotating friction members, e.g. rollers, brushes, or cylinders {(with suction rollers B65H29/243)} · CPC title