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

Patent metadata

Field	Value
Publication number	US-11204570-B2
Application number	US-201916594772-A
Country	US
Kind code	B2
Filing date	Oct 7, 2019
Priority date	Nov 29, 2018
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

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

• G03G15/2032 Primary

  Retractable heating or pressure unit · CPC title

• B65H29/20

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

• B65H2801/27

  Devices located downstream of office-type machines · CPC title

• B65H2511/224

  Nip between rollers, between belts or between rollers and belts · CPC title

• B65H2404/1441

  involving controlled actuator · CPC title