Rotation detecting unit, sheet feeding device and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9758327-B2
Application number	US-201615256999-A
Country	US
Kind code	B2
Filing date	Sep 6, 2016
Priority date	Sep 11, 2015
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A rotation detecting unit includes a light emitting device, a light receiving device, an output device, a rotatable plate, and a discriminating device. The rotatable plate includes a first portion and a second portion which are alternately provided along a circumferential direction, a third portion provided between the first portion and the second portion, and a fourth portion provided between the second portion and the first portion. When a region of the first portion is irradiated with light emitted from the light emitting device and received by the light receiving device, received light quantity of the light receiving device is a maximum. When a region of the second portion is irradiated with the light, the received light quantity is a minimum. When the third or fourth portion is irradiated with the light, the received light quantity is larger than the minimum and is smaller than the maximum.

First claim

What is claimed is:

1. A rotation detecting unit comprising:
a light emitting device for emitting light;
a light receiving device for receiving the light;
an output device for outputting an output waveform changing depending on a received light quantity of said light receiving device;
a rotatable plate, rotatably supported by a shaft, for being irradiated with the light emitted from said light emitting device and entering said light receiving device; and
a discriminating device for discriminating a state of said rotatable plate on the basis of the output waveform of said output device,
wherein said rotatable plate includes a first portion and a second portion which are alternately provided along a circumferential direction, a third portion provided between said first portion and said second portion with respect to the circumferential direction, and a fourth portion provided between said second portion and said first portion with respect to the circumferential direction,
wherein when a region of said first portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, the received light quantity of said light receiving device is a maximum,
when a region of said second portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, the received light quantity of said light receiving device is a minimum, and
wherein when said third portion or said fourth portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, the received light quantity of said light receiving device is larger than the minimum and is smaller than the maximum.

2. A rotation detecting unit according to claim 1 , wherein when said rotatable plate rotates from a state in which said first portion is irradiated with the light emitted from said light emitting device and received by said light receiving device toward a state in which said second portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, in a state in which said third portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, the received light quantity of said light receiving device gradually decreases from the maximum toward the minimum.

3. A rotation detecting unit according to claim 2 , wherein said light receiving device includes light receiving region limiting means, having an output which opens toward said light emitting device, for limiting the light received by said light receiving device to light with which a region of the output is irradiated,
wherein said rotatable plate includes an output portion penetrating in an axial direction and a light blocking portion for blocking the light emitted from said light emitting device and to be received by said light receiving device,
wherein said first portion includes said output portion,
wherein said second portion includes said light blocking portion,
wherein said third portion include said output portion and said light blocking portion, and
wherein when said rotatable plate rotates from the state in which said first portion is irradiated with the light toward the state in which said second portion is irradiated with the light, a proportion of an area occupied by said light blocking portion to an area occupied by said output portion in the output of said light receiving region limiting means gradually increases.

4. A rotation detecting unit according to claim 3 , wherein when said rotatable plate rotates from the state in which said first portion is irradiated with the light toward the state in which said second portion is irradiated with the light, a boundary portion between said output portion and said light blocking portion in said third portion obliquely crosses an edge portion of the output of said light receiving region limiting means.

5. A rotation detecting unit according to claim 4 , wherein the boundary portion between said output portion and said light blocking portion in said third portion extends obliquely with respect to a radial direction of said rotatable plate.

6. A rotation detecting unit according to claim 4 , wherein the boundary portion between said output portion and said light blocking portion in said third portion extends along a radial direction of said rotatable plate.

7. A rotation detecting unit according to claim 1 , wherein when said rotatable plate rotates from a state in which said second portion is irradiated with the light emitted from said light emitting device and received by said light receiving device toward a state in which said first portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, in a state in which said fourth portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, the received light quantity of said light receiving device gradually increases from the minimum toward the maximum.

8. A rotation detecting unit according to claim 7 , wherein said light receiving device includes light receiving region limiting means, having an output which opens toward said light emitting device, for limiting the light received by said light receiving device to light with which a region of the output is irradiated,
wherein said rotatable plate includes an output portion penetrating in an axial direction and a light blocking portion for blocking the light emitted from said light emitting device and to be received by said light receiving device,
wherein said first portion includes said output portion,
wherein said second portion includes said light blocking portion,
wherein said fourth portion include said output portion and said light blocking portion, and
wherein when said rotatable plate rotates from the state in which said second portion is irradiated with the light toward the state in which said first portion is irradiated with the light, a proportion of an area occupied by said light blocking portion to an area occupied by said output portion in the output of said light receiving region limiting means gradually decreases.

9. A rotation detecting unit according to claim 8 , wherein when said rotatable plate rotates from the state in which said second portion is irradiated with the light toward the state in which said first portion is irradiated with the light, a boundary portion between said light blocking portion and said output portion in said fourth portion obliquely crosses an edge portion of the output of said light receiving region limiting means.

10. A rotation detecting unit according to claim 9 , wherein the boundary portion between said light blocking portion and said output portion in said fourth portion extends obliquely with respect to a radial direction of said rotatable plate.

11. A rotation detecting unit according to claim 9 , wherein the boundary portion between said light blocking portion and said output portion in said fourth portion extends along a radial direction of said rotatable plate.

12. A rotation detecting unit according to claim 1 , wherein when said rotatable plate rotates from a state in which said first portion is irradiated with the light emitted from said light emitting device and received by said light receiving device toward a state in which said second portion is irradiated with the light emitted from said light emitting device and received by said light receiving device, in a state in which said third portion is irradiated with the light emitted from said light emitting device and received by

Assignees

• Canon Kk

Inventors

• Suzuki Masato

Classifications

• B65H1/08

  with means for advancing the articles to present the articles to the separating device {(B65H1/02 takes precedence)} · CPC title

• B65H3/0661

  for separating inclined-stacked articles with separator rollers above the stack · CPC title

• B65H2553/51

  Encoders, e.g. linear · CPC title

• B65H1/04

  adapted to support articles substantially horizontally, e.g. for separation from top of pile · CPC title

• B65H3/0607

  cooperating with means for automatically separating the pile from roller or rotary separator after a separation step · CPC title