Hinge mechanism for platen cover

• US 20040045129A1
• Filed: 09/04/2003
• Published: 03/11/2004
• Est. Priority Date: 09/06/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Marimoto, Yasumasa, Matsumoto, Yoshitaka, Tamehira, Masato, Nishizato, Yoshiyuki
• Granted Patent: US 7,240,401 B2
• Time in Patent Office: Days
• US Class Current: 16/223
• CPC Class Codes: E05D 11/1064 with a coil spring perpendicular to the pivot axis
• CPC Class Codes: E05Y 2999/00 Subject-matter not otherwise provided for in this subclass
• CPC Class Codes: G03G 15/605 Holders for originals or exposure platens for photographic purposes in general G03B

Abstract

A hinge mechanism of an image forming apparatus supporting a platen cover for holding an original at a fixed position on a platen glass includes a hinge unit for supporting the platen cover in such a manner that the platen cover can be opened and closed by swinging it up and down, a compression coil spring for biasing the platen cover in its opening direction, and a hinge holder attached to a housing of the apparatus for accommodating the compression coil spring. The hinge unit is provided with a hinge torque keeping mechanism which causes the compression coil spring to produce a specific amount of hinge torque to bias the platen cover in its opening direction even when the platen cover is closed.

Claims

1. A hinge mechanism supporting a platen cover for holding an original at a fixed position on a platen glass, said hinge mechanism comprising:

a hinge unit for supporting the platen cover in such a manner that the platen cover can be opened and closed by swinging it up and down;

an elastic member for biasing the platen cover in its opening direction; and

a hinge holder attached to a housing of an apparatus for accommodating said elastic member;

wherein said hinge unit is provided with a hinge torque keeping mechanism which causes said elastic member to produce a specific amount of hinge torque to bias the platen cover in its opening direction even when the platen cover is closed.

2. The hinge mechanism according to claim 1, wherein said hinge torque keeping mechanism includes a cam for ensuring smooth opening and closing action of the platen cover and a roller which rolls over said cam.

3. The hinge mechanism according to claim 2, wherein said cam is so shaped as to hold the platen cover stationary at a particular open position.

4. The hinge mechanism according to claim 2, wherein said cam is shaped such that a generally upward directed perpendicular to a tangent line passing a point of contact between said cam and said roller is offset from a pivot axis of said cam when the platen cover is closed.

5. The hinge mechanism according to claim 4, wherein the generally upward directed perpendicular to the tangent line passing the point of contact between said cam and said roller is offset from the pivot axis of said cam toward the front of the platen cover.