SHEET STACKING DEVICE AND IMAGE FORMING APPARATUS

• US 20090134572A1
• Filed: 11/25/2008
• Published: 05/28/2009
• Est. Priority Date: 11/26/2007
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Fukatsu, Yasuo, Obuchi, Yusuke, Watanabe, Naoto
• Granted Patent: US 8,794,622 B2
• Time in Patent Office: Days
• US Class Current: 271/279
• CPC Class Codes: B65H 2220/01 indicating an entity as a function of which control, adjustment or change is performed, i.e. input
• CPC Class Codes: B65H 2220/02 indicating an entity which is controlled, adjusted or changed by a control process, i.e. output
• CPC Class Codes: B65H 2220/11 indicating that the input or output entities exclusively relate to machine elements
• CPC Class Codes: B65H 2301/131 single width or double width
• CPC Class Codes: B65H 2402/45 Doors
• CPC Class Codes: B65H 2405/15 Large capacity supports arrangements
• CPC Class Codes: B65H 2405/331 Juxtaposed compartments
• CPC Class Codes: B65H 2405/3311 for storing articles horizontally or slightly inclined
• CPC Class Codes: B65H 2407/10 Safety means, e.g. for preventing injuries or illegal operations
• CPC Class Codes: B65H 2511/20 Location in space
• CPC Class Codes: B65H 2801/06 Office-type machines, e.g. photocopiers
• CPC Class Codes: B65H 31/18 Positively-acting mechanical devices

Abstract

A stacker includes a plurality of sheet stacking units individually movable upward and downward. Sheets are selectively stacked onto either of the stacker trays. To remove the sheets stacked on one of the stacker trays, a door is opened. In a state where the door is open, the stacker trays moved by respective elevation units are movable only downward. In this manner, accidental upward movement of each of the stacker trays caused by a malfunction of a motor or the like is regulated, whereby damage to the stacker is prevented.

Claims

1. A sheet stacking device comprising:

a sheet stacking unit configured to be movable upward and downward;

an elevation unit configured to raise and lower the sheet stacking unit;

a door configured to be opened when sheets stacked on the sheet stacking unit are removed;

a drive source configured to drive the elevation unit; and

a transmission unit transmitting driving forces of the drive source to the elevation unit to raise and lower the sheet stacking unit,

wherein, in a state where the door is open, the transmission unit transmits to the elevation unit only the driving force of the drive source to lower the sheet stacking unit.

2. The sheet stacking device according to claim 1, wherein the elevation unit includes a regulating unit configured to regulate a lowering operation of the elevation unit so as to prevent the sheet stacking unit from being lowered beyond a predetermined position in a state where the door is open.

3. The sheet stacking device according to claim 2,

wherein the regulating unit includes:

a first detecting unit configured to detect the door being open; and

a second detecting unit configured to detect whether the sheet stacking unit, which is being lowered, has reached the predetermined position, and

wherein the drive source stops driving the elevation unit if the second detecting unit detects that the sheet stacking unit has reached the predetermined position while the first detecting unit detects the door being open.

4. The sheet stacking device according to claim 1, wherein the sheet staking unit includes a plurality of the sheet stacking units.

5. An image forming apparatus comprising:

an image forming unit configured to form an image on a sheet;

a sheet stacking unit configured to be movable upward and downward and onto which sheets having images formed by the image forming unit are to be stacked;

an elevation unit configured to raise and lower the sheet stacking unit;

a door configured to be opened when the sheets stacked on the sheet stacking unit are removed;

a drive source configured to drive the elevation unit; and

a transmission unit transmitting driving forces of the drive source to the elevation unit for raising and lowering the sheet stacking unit,

wherein, in a state where the door is open, the transmission unit transmits to the elevation unit only the driving force of the drive source to lower the sheet stacking unit.

6. The image forming apparatus according to claim 5, wherein the elevation unit includes a regulating unit configured to regulate a lowering operation of the elevation unit so as to prevent the sheet stacking unit from being lowered beyond a predetermined position in a state where the door is open.

7. The image forming apparatus according to claim 6,

wherein the regulating unit includes:

a first detecting unit configured to detect the door being open; and

a second detecting unit configured to detect whether the sheet stacking unit, which is being lowered, has reached the predetermined position, and

wherein the driving source stops driving the elevation unit if the second detecting unit detects that the sheet stacking unit has reached the predetermined position while the first detecting unit detects the door being open.

8. The image forming apparatus according to claim 5, wherein the sheet staking unit includes a plurality of the sheet stacking units.