Original reading unit, image forming apparatus and image scanner

• US 20060087704A1
• Filed: 09/20/2005
• Published: 04/27/2006
• Est. Priority Date: 10/25/2004
• Status: Active Grant

• Current Assignee: BASF Corporation (BASF SE), Oki Data Corporation (OKI Electric Industry Company Limited)
• Original Assignee: Seiko I Infotech, Inc. (OKI Electric Industry Company Limited)
• Inventors: Hirayama, Shinobu
• Granted Patent: US 7,595,913 B2
• Time in Patent Office: Days
• US Class Current: 358/474
• CPC Class Codes: H04N 1/02409 Focusing, i.e. adjusting the focus of the scanning head
• CPC Class Codes: H04N 1/0313 Direct contact pick-up heads, i.e. heads having no array of elements to project the scanned image elements onto the photodectors
• CPC Class Codes: H04N 1/1933 Staggered element arrays, e.g. arrays with elements arranged in a zigzag
• CPC Class Codes: H04N 1/1934 Combination of arrays
• CPC Class Codes: H04N 2201/0241 in a direction parallel to the main-scanning direction
• CPC Class Codes: H04N 2201/02412 in a direction parallel to the sub-scanning direction
• CPC Class Codes: H04N 2201/02414 in a direction perpendicular to the plane of the photodetector elements, e.g. in the direction of the optical axis H04N1/02409 takes precedence
• CPC Class Codes: H04N 2201/02418 Rotation about the optical axis
• CPC Class Codes: H04N 2201/02429 Photodetector element, e.g. CCD array
• CPC Class Codes: H04N 2201/02447 using elastic means, e.g. springs H04N2201/02445 takes precedence
• CPC Class Codes: H04N 2201/02449 using a reference element, e.g. a stop

Abstract

According to the present invention, between a unit base and a transparent original support plate, multiple sensor assemblies are arranged, to form a zigzag pattern, as a first array for reading an original and a second array for reading the original following the first array. Each of the sensor assemblies includes a sensor holder, a line sensor and a focus setup unit. Each of the sensor holders, which serve as fulcrums, are rotatable at a single pivot (a rotation center), along the wall of a unit base that is parallel to the original support plate. When the sensor holders are rotated and positioned at predetermined locations, they are fixed to the wall. The line sensors 51 are held, relative to the sensor holders, in the main scanning direction and in the sub-scanning direction, and are moved in an approaching or separating direction in which the line sensors approach or are separated from the wall and the original support plate. The focus setup units, each of which includes coil springs and spacers, move the line sensors 51 in the approaching or separating direction, and position the line sensors 51 at locations whereat focuses are adjusted.

Claims

1. An original reading unit comprising:

a unit base;

a transparent original support plate attached to the unit base; and

multiple sensor assemblies arranged, in a zigzag pattern, to form on the unit base a first array, extended in a main scanning direction, for performing the first reading of an original, and a second array, also extended in the main scanning direction, for reading the original following the first array,

wherein each of the sensor assemblies includes

a sensor holder, which, as a fulcrum, can be pivoted at a single rotation center, along a wall of the unit base, to a predetermined position and fixed to the wall,

a line sensor, which is held, relative to the sensor holder, so as not to be shifted in the main scanning direction or in the sub-scanning direction and which is movable, in an approaching or a separating direction, so as to be brought into contact with and separated from the wall and the original support plate, and

a focus setup unit, which moves the line sensor in the approaching or separating direction and which positions the line sensor at a location whereat focus can be adjusted.

2. An original reading unit according to claim 1, wherein a first urging member that pushes a line sensor from one longitudinal end in the main scanning direction and a second urging member that pushes the line sensor in the sub-scanning direction are employed to hold the line sensor, relative to the sensor holder, so that the line sensor is not to be moved in the main scanning direction and the sub-scanning direction.

3. An original reading unit according to claim 1, wherein at least part of the rotation center is located in a projection area for the line sensors, relative to the wall.

4. An original reading unit according to claim 1, wherein the rotation center is located immediately under, or in the vicinity of, a light-receiving device, the first that is read among an array of light-receiving devices for the line sensors.

5. An original reading unit according to claim 1, wherein the focus setup unit includes:

pressing members, for moving the line sensors toward the original support plate; and

spacers, which are sandwiched between the line sensors and the original plate support to define focal distances for the line sensors.

6. An original reading unit according to claim 5, wherein an urging member is employed as the pressing member.

7. An original reading unit according to claim 6,

wherein a first support member that includes a guide portion, for guiding the line sensors that move in the approaching or separating direction, and for regulating the movement of the line sensors in the sub-scanning direction, and a stopper portion, for regulating the movement of the line sensors in the main scanning direction, is attached to one longitudinal end of the sensor holder;

wherein a second support member, which includes a guide portion for guiding the line sensors that move in the approaching or separating direction and for regulating the movement of the line sensors in the sub-scanning direction, is attached to the other longitudinal end of the sensor holder;

wherein fitting portions, which are slidably fitted into the guide portions of the first and second support members, and an engagement portion, which abuts upon the stopper portion, are formed for the line sensors;

wherein first urging members are attached to the first support portion to apply an urging force, in the main scanning direction, to the line sensors, thereby causing the engagement portion to abut upon the stopper portion, and second urging members are sandwiched between the sensor holder and the line sensors to apply an urging force, in the sub-scanning direction, to the line sensors;

wherein pressing members, which are formed of the first and second urging members, are sandwiched between the first and second support members and the line sensors; and

wherein the spacers, which define the focal distances of the line sensors, are sandwiched between the line sensors and the original support plates.

8. An image forming apparatus comprising an original reader that includes an original reading unit according to claim 1.

9. An image scanner comprising an original reader that includes an original reading unit according to claim 1.