Sheet feeder and image forming apparatus that ensure stabilized sheet conveyance

Patent metadata

Field	Value
Publication number	US-10173852-B2
Application number	US-201715789961-A
Country	US
Kind code	B2
Filing date	Oct 21, 2017
Priority date	Oct 21, 2016
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A sheet feeder includes an apparatus main body, a sheet housing unit, and a sheet feeding unit. The sheet housing unit includes a housing space, a lift plate, an elevating mechanism, and a side fence. The elevating mechanism includes a pair of first wires, a pair of second wires, first pulleys, second pulleys, a reel, and a pair of first connecting members. The reel winds up the pair of first wires and the pair of second wires. The pair of first connecting members are connected to be relatively movable with respect to the lift plate in a vertical direction, causes a relative position to vary with respect to the lift plate in a vertical direction in accordance with a weight of the plurality of sheets loaded on the lift plate, and causes the lift plate to move upward when the weight is lighter than a predetermined value.

First claim

What is claimed is:

1. A sheet feeder comprising:
an apparatus main body;
a sheet housing unit insertably and removably located on the apparatus main body, the sheet housing unit for housing a plurality of sheets, and
a sheet feeding unit for extracting in a first direction a sheet located at an uppermost position in the plurality of sheets; wherein
the sheet housing unit includes
a housing space that has an opening in an upper side, the housing space being defined by a bottom portion, a pair of first sidewalls that is located upright from the bottom portion and are mutually opposed in a second direction perpendicular to the first direction, and a pair of second sidewalls mutually opposed in the first direction,
a lift plate for carrying the plurality of sheets, the lift plate having downstream-side end portions along an edge of the lift plate that is sheet-feeding downstream in the first direction and having upstream-side end portions along an edge of the lift plate that is sheet-feeding upstream in the first direction, and the lift plate arranged for moving up and down inside the housing space,
an elevating mechanism that causes the lift plate to move up and down, and
a side fence located upright from the bottom portion, the side fence abutting on a side end of the plurality of sheets along the first direction;

the sheet feeding unit is arranged in the apparatus main body on an upper side of the sheet housing unit along the downstream-side end portions of the lift plate, and includes a pickup roller for abutting on a top surface of the sheet located at the uppermost position in the plurality of sheets to deliver the sheet;
the elevating mechanism includes
a pair of first wires located outside the pair of first sidewalls in the second direction, the pair of first wires suspending the downstream-side end portions of the lift plate at both sides in the second direction of the lift plate,
a pair of second wires located outside the pair of first sidewalls in the second direction, the pair of second wires suspending the upstream-side end portions of the lift plate at both sides in the second direction of the lift plate,
a pair of first pulleys where the pair of first wires is laid across the first pulleys being arranged on the first sidewalls vertically below the pickup roller, viewed from the second direction,
a pair of second pulleys where the pair of second wires is laid across,
a motor-driven reel for winding up the pair of first wires and the pair of second wires to a predetermined point where the downstream-side end portions of the lift plate are near the pair of first pulleys, and
a pair of first connecting members coupling the downstream-side end portions of the lift plate to the first wires to be movable vertically relative to the first wires, in a connection counterbalanced such that the lift plate is caused to move upward, bringing the top surface of the sheet located at the uppermost position in the plurality of sheets into abutment against the pickup roller, when the weight of the plurality of sheets that the lift plate carries is lighter than a predetermined value based on the sheets' weight at the predetermined point where the downstream-side end portions of the lift plate are near the pair of first pulleys.

2. The sheet feeder according to claim 1 , wherein:
the lift plate includes a cut-out portion between the upstream-side end portions and the downstream-side end portions; and
the side fence is located in the cut-out portion.

3. The sheet feeder according to claim 1 , wherein the elevating mechanism further includes a pair of second connecting members that connect the upstream side end portions of the lift plate to the second wires.

4. The sheet feeder according to claim 1 , wherein the pair of first connecting members each include a wire connecting member that is mounted to the lift plate and is relatively movable in a vertical direction with respect to the lift plate and a biasing member that is located between the wire connecting member and the lift plate and biases the lift plate upward.

5. The sheet feeder according to claim 4 , wherein the wire connecting member includes:
a mounting portion formed to have a guide groove vertically extending;
a wire connecting portion that extends outward in the second direction in a lower side of the guide groove of the mounting portion and connects to the first wire or the second wire;
a spring-securing portion that extends inward in the second direction and secures the biasing member; and
a connection pin that is inserted into the guide groove and is secured to the lift plate.

6. An image forming apparatus, comprising:
the sheet feeder according to claim 1 ; and
an image forming unit that forms an image on the sheet fed from the sheet feeder.

7. A sheet feeder comprising:
an apparatus main body;
a sheet housing unit insertably and removably located on the apparatus main body, the sheet housing unit housing a plurality of sheets; and
a sheet feeding unit for extracting in a first direction a sheet located at an uppermost position in the plurality of sheets; wherein
the sheet housing unit includes
a housing space that has an opening in an upper side, the housing space being defined by a bottom portion, a pair of first sidewalls that is located upright from the bottom portion and are mutually opposed in a second direction perpendicular to the first direction, and a pair of second sidewalls mutually opposed in the first direction,
a lift plate for carrying the plurality of sheets, the lift plate having downstream-side end portions along an edge of the lift plate sheet-feeding downstream in the first direction, and the lift plate arranged for moving up and down inside the housing space,
an elevating mechanism that causes the lift plate to move up and down, and
a side fence located upright from the bottom portion, the side fence abutting on a side end of the plurality of sheets along the first direction;

the elevating mechanism includes
a pair of first wires located outside the pair of first sidewalls in the second direction, the pair of first wires suspending end portions in a downstream side of the first direction of the lift plate at both sides in the second direction of the lift plate,
a pair of second wires located outside the pair of first sidewalls in the second direction, the pair of second wires suspending end portions in an upstream side of the first direction of the lift plate at both sides in the second direction of the lift plate,
a pair of first pulleys where the pair of first wires is laid across,
a pair of second pulleys where the pair of second wires is laid across,
a reel that winds up the pair of first wires and the pair of second wires, and
a pair of first connecting members that connect the end portions in the downstream side of the first direction of the lift plate to the first wires; and

the pair of first connecting members are connected to be relatively movable with respect to the lift plate in a vertical direction, to cause a relative position to vary with respect to the lift plate in a vertical direction in accordance with a weight of the plurality of sheets loaded on the lift plate, and cause the lift plate to move upward when the weight is lighter than a predetermined value, the pair of first connecting members each including a wire connecting member that is mounted to the lift plate and is relatively movable in a vertical direction with respect to the lift plate and including a biasing member that is located between the wire connecting member and the lift plate and biases the lift plate upward, and the wire connecting members each including
a mounting portion formed to have a vertically extending guide groove,
a wire connecting portion extending

Assignees

• Kyocera Document Solutions Inc

Inventors

• Yamaguchi Yoshihiro

Classifications

• B65H2405/15

  Large capacity supports arrangements · CPC title

• B65H31/18

  Positively-acting mechanical devices · CPC title

• B65H1/20

  controlled by weight of pile; Floating arrangements · CPC title

• B65H2801/06

  Office-type machines, e.g. photocopiers · CPC title

• B65H1/12

  comprising spring {(B65H1/022 takes precedence)} · CPC title