Image forming apparatus

Patent metadata

Field	Value
Publication number	US-10564575-B2
Application number	US-201715687905-A
Country	US
Kind code	B2
Filing date	Aug 28, 2017
Priority date	Oct 10, 2013
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

An image forming apparatus includes: an image carrying unit; a unit-to-be-moved; a pulse motor; a moving mechanism including a rotatable member provided with a member-to-be-detected; a detecting portion; an executing portion; and a controller for causing the executing portion to execute a first stop mode on the basis of detection of the detecting portion when the unit-to-be-moved is changed in position from the second or third position to the first position and to execute a second stop mode on the basis of a pulse number of a driving signal when the unit-to-be-moved is changed in position from the first or third position to the second position and when the unit-to-be-moved is changed in position from the first or second position to the third position, and for making the change at least between the second and third positions by only unidirectional rotation of the pulse motor.

First claim

What is claimed is:

1. An image forming apparatus comprising:
an image bearing member;
a motor rotatable hi-directionally;
a unit-to-be-moved configured to be moved so as to change a position thereof relative to said image bearing member;
a moving mechanism, including a cam rotated by said motor, configured to move said unit-to-be-moved to first to third positions by switching a phase of said cam to first to third phases corresponding to the first to third positions, respectively;
a sensor configured to detect only the first phase of said cam; and
a controller configured to control drive of said motor on the basis of a detection result of said sensor,
wherein said controller controls the drive of said motor so that switching between the first phase and the second phase is made by bi-directional rotation of said motor,
wherein said controller controls the drive of said motor so that switching between the third phase and the first phase is made by unidirectional rotation or bi-directional rotation of said motor, and
wherein said controller controls the drive of said motor so that switching between the second phase and the third phase is made by rotation of said motor in one direction and is not made by rotation of said motor in the other direction.

2. The image forming apparatus according to claim 1 , wherein said controller controls the drive of said motor so as to permit switching from the second position to the third position without passing through the first position and so as not to permit switching from the third position to the second position without passing through the first position and so as to permit switching from the third position to the first position without passing through the second position.

3. The image forming apparatus according to claim 2 , wherein said controller controls the drive of said motor so as not to permit switching from the first phase to the third phase by the rotation of said motor in the second direction.

4. The image forming apparatus according to claim 2 , wherein said controller controls the drive of said motor so as to permit switching from the third position to the first position without passing through the second position.

5. The image forming apparatus according to claim 1 , wherein said image bearing member includes a plurality of photosensitive members each for carrying a toner image,
wherein said unit-to-be-moved is an intermediary transfer belt onto which the toner images are to be transferred from the plurality of photosensitive members, respectively, and
wherein the first position is an all contact position where all of the plurality of photosensitive members contact the intermediary transfer belt,
the second position is a partial contact position where a part of the plurality of photosensitive members contacts the intermediary transfer belt, and
the third position is an all separation position where all of the plurality of photosensitive members are separated from the intermediary transfer belt.

6. The image forming apparatus according to claim 5 , wherein said image forming apparatus is capable of executing an operation in a first image forming mode and an operation in a second image forming mode, and
wherein said controller controls the drive of said motor so that the phase of said cam is the first phase during execution of the operation in the first image forming mode and so that the phase of said cam is the second phase during execution of the operation in the second image forming mode.

7. The image forming apparatus according to claim 5 , further comprising an intermediary transfer unit which includes the intermediary transfer belt and which is mountable to and dismountable from a main assembly of said image forming apparatus,
wherein when the phase of said cam is in the third phase, said intermediary transfer unit is mountable to and dismountable from the main assembly of said image forming apparatus.

8. The image forming apparatus according to claim 1 , wherein said image bearing member is an intermediary transfer belt onto which toner images are to be transferred, and
wherein said unit-to-be-moved is a secondary transfer member configured to transfer the toner images to a recording material.

9. The image forming apparatus according to claim 8 , wherein the first position is a contact position where the secondary transfer member contacts the intermediary transfer belt, the second position is a first separation position where the secondary transfer member is separated from the intermediary transfer belt at a first distance, and the third position is a second separation position where the secondary transfer member is separated from the intermediary transfer belt at a second distance longer than the first distance.

10. The image forming apparatus according to claim 1 , wherein in a case where drive of said motor is stopped in the first phase from the second phase, said controller controls said motor on the basis of a first driving pulse determined in advance, and wherein in a case where drive of said motor is stopped in the second and third phases from the first phase, said controller controls said motor on the basis a second driving pulse determined in advance and the detecting result of the sensor.

Assignees

• Canon Kk

Inventors

• Tajiri Tsuyoshi

Classifications

• G03G15/1615 Primary

  relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning · CPC title

• G03G15/01

  for producing multicoloured copies · CPC title

• G03G15/50 Primary

  Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control (sequencing control G03G21/14) · CPC title