Sheet feeding device, image forming apparatus, and method for controlling sheet feeding device

Patent metadata

Field	Value
Publication number	US-10308451-B2
Application number	US-201816057007-A
Country	US
Kind code	B2
Filing date	Aug 7, 2018
Priority date	Aug 24, 2017
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

A sheet feeding device includes a cassette and a first sensor unit. The first sensor unit includes a first conductive plate and a first coil circuit board, so as to output a first output value corresponding to a position of the first conductive plate. A first moving mechanism moves the first conductive plate according to remaining quantity of paper sheets. The first conductive plate is attached to the cassette. The first coil circuit board is not attached to the cassette. A control unit determines current remaining quantity of paper sheets based on a magnitude of the first output value. The control unit determines whether or not the cassette is attached based on the magnitude of the first output value and a reference value.

First claim

What is claimed is:

1. A sheet feeding device comparing:
a cassette including a sheet placing plate having an upper surface on which paper sheets are set, the cassette being detachable and attachable;
a first sensor unit including a first conductive plate and a first coil circuit board on which a coil pattern is printed, the first coil circuit board being applied with a voltage so that a magnetic field is generated, and so that the first sensor unit outputs a first output value corresponding to a position of the first conductive plate;
a first moving mechanism arranged to move the first conductive plate so that a facing area between the first coil circuit board and the first conductive plate is increased or decreased according to remaining quantity of paper sheets in the cassette;
a storage unit arranged to store remaining quantity detection data for determining current remaining quantity of paper sheets corresponding to the first output value, and a reference value for determining whether or not the cassette is attached; and
a control unit arranged to recognize a magnitude of the first output value, wherein
the first conductive plate is attached to the cassette,
the first coil circuit board is disposed at a position facing the first conductive plate in a non-contact manner when the cassette is attached, but is not attached to the cassette, and
the control unit determines the current remaining quantity of paper sheets based on the magnitude of the first output value and the remaining quantity detection data, and determines whether or not the cassette is attached based on the magnitude of the first output value and the reference value.

2. The sheet feeding device according to claim 1 , wherein
the first sensor unit outputs the first output value having a larger value as a distance between the first coil circuit board and the first conductive plate is smaller, and as the facing area between the first coil circuit board and the first conductive plate is larger, and
the control unit determines that the cassette is not attached when the first output value is smaller than the reference value, and determines that the cassette is attached when the first output value is larger than or equal to the reference value.

3. The sheet feeding device according to claim 1 , further comprising:
a sheet feed roller disposed above the sheet placing plate so as to send out paper sheets set on the sheet placing plate; and
a lifting mechanism arranged to move the sheet placing plate upward and downward, and to move the sheet placing plate upward until the sheet feed roller contacts with the paper sheets on the sheet placing plate when the cassette is attached, wherein
the first moving mechanism moves the first conductive plate so that the facing area between the first coil circuit board and the first conductive plate is increased or decreased according to a height of the sheet placing plate,
the lifting mechanism sets the sheet placing plate at a lower limit position when the cassette is detached, and
the reference value is determined based on the first output value when the sheet placing plate is at the lower limit position.

4. The sheet feeding device according to claim 3 , wherein
the lifting mechanism includes a drive shaft, a lifting member fixed to the drive shaft so as to lift the sheet placing plate to move upward, and a lifting motor arranged to rotate the drive shaft,
the first moving mechanism includes a rotation plate fixed to the drive shaft so as to change its rotation angle according to a rotation angle of the drive shaft,
the first conductive plate has a substantially triangular shape and is fixed to the rotation plate,
the first coil circuit board is disposed at a position facing the rotation plate when the cassette is attached, and
as the sheet placing plate moves upward, the rotation plate moves the first conductive plate to be close to the center of the first coil circuit board when viewing the first coil circuit board from front, so that the facing area between the first coil circuit board and the first conductive plate is increased.

5. The sheet feeding device according to claim 1 , wherein
the cassette includes width regulation cursors capable of moving to slide in a direction perpendicular to a conveying direction, so as to regulate a position of set paper sheets, a second moving mechanism, and a second sensor unit,
the second sensor unit includes a second conductive plate and a second coil circuit board on which a coil pattern is printed,
the second sensor unit applies a voltage to the second coil circuit board so that a magnetic field is generated, and outputs a second output value corresponding to a position of the second conductive plate,
the second conductive plate is attached to the cassette,
the second coil circuit board is not attached to the cassette, but is disposed at a position facing the second conductive plate in a non-contact manner when the cassette is attached,
the second conductive plate has a movement range that is smaller than a length of the second coil circuit board in the longitudinal direction,
the second moving mechanism moves the second conductive plate in the longitudinal direction of the second coil circuit board according to a position of the width regulation cursor,
the storage unit stores first sheet size data for determining a paper sheet size in a direction perpendicular to the conveying direction corresponding to a magnitude of the second output value, and
when determining that the cassette is attached, the control unit recognizes a size of set paper sheets in the direction perpendicular to the conveying direction based on the magnitude of the second output value and the first sheet size data.

6. The sheet feeding device according to claim 1 , wherein
the cassette includes a rear end regulation cursor capable of moving to slide in a conveying direction, so as to regulate a position of set paper sheets, a third moving mechanism, and a third sensor unit,
the third sensor unit includes a third conductive plate and a third coil circuit board on which a coil pattern is printed,
the third sensor unit applies a voltage to the third coil circuit board so that a magnetic field is generated, and outputs a third output value corresponding to a position of the third conductive plate,
the third conductive plate is attached to the cassette,
the third coil circuit board is not attached to the cassette, but is disposed at a position facing the third conductive plate in a non-contact manner when the cassette is attached,
the third conductive plate has a movement range that is smaller than a length of the third coil circuit board in the longitudinal direction,
the third moving mechanism moves the third conductive plate in the longitudinal direction of the third coil circuit board according to a position of the rear end regulation cursor,
the storage unit stores second sheet size data for determining a paper sheet size in the conveying direction corresponding to a magnitude of the third output value, and
when determining that the cassette is attached, the control unit recognizes a size of set paper sheets in the conveying direction based on the magnitude of the third output value and the second sheet size data.

7. The sheet feeding device according to claim 1 , wherein
the storage unit stores the remaining quantity detection data in which a no sheet value and a full sheet value are defined,
the no sheet value is the first output value when the sheet placing plate is moved upward to the upper limit position in a state without paper sheets,
the full sheet value is the first output value when the sheet placing plate is moved upward to the upper limit position in a state with full paper sheets, and
the control uni

Assignees

• Kyocera Document Solutions Inc

Inventors

• Kikuta Tomoyuki

Classifications

• B65H2553/23

  Capacitive detectors, e.g. electrode arrangements · CPC title

• B65H2220/01

  indicating an entity as a function of which control, adjustment or change is performed, i.e. input · CPC title

• B65H2511/51

  Presence · CPC title

• B65H1/18 Primary

  controlled by height of pile · CPC title

• B65H2511/152

  Operations & Transport · mapped topic