Book document reading device

• US 5,847,845 A
• Filed: 06/07/1995
• Issued: 12/08/1998
• Est. Priority Date: 03/01/1993
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Shiina, Susumu, Takahashi, Hiroshi, Bannai, Kazunori, Fujioka, Tetsuya, Taguchi, Kazushige
• Primary Examiner(s): Vu, Kim
• Assistant Examiner(s): Harris, Tia M.
• Application Number:
  US08/474,244
• Time in Patent Office: 1,280 Days
• Field of Search: 358/475, 358/474, 358/401, 358/450, 358/406, 358/494, 358/497, 355/25, 399/362
• US Class Current: 358/475
• CPC Class Codes: G03G 15/043 with means for controlling illumination or exposure G03G15/041 takes precedence
• CPC Class Codes: G03G 2215/00282 Book
• CPC Class Codes: H04N 1/0464 capable of performing non-simultaneous scanning at more than one scanning station
• CPC Class Codes: H04N 1/1017 the main-scanning components remaining positionally invariant with respect to one another in the sub-scanning direction
• CPC Class Codes: H04N 1/1026 using a belt or cable
• CPC Class Codes: H04N 1/1043 of a sensor array
• CPC Class Codes: H04N 1/1048 of a lens or lens arrangement
• CPC Class Codes: H04N 1/1052 of a mirror
• CPC Class Codes: H04N 1/193 using electrically scanned linear arrays , e.g. linear CCD arrays
• CPC Class Codes: H04N 1/40056 Circuits for driving or energising particular reading heads or original illumination means H04N1/401, H04N1/407 take precedence
• CPC Class Codes: H04N 1/401 Compensating positionally unequal response of the pick-up or reproducing head H04N1/403 takes precedence
• CPC Class Codes: H04N 2201/0434 specially adapted for scanning pages of a book

Abstract

An image reading device capable of preventing, by increasing the quantity of light at the center or bound portion of a spread book document, the quantity of light from becoming short and preventing density from becoming irregular due to the deviation of a focus. At and around the center of a spread book document where the document is bound, the quantity of light for illumination or the amplification gain of image data read from the document is increased. A plurality of fluorescent lamps illuminate the surface of the document at the upstream side and downstream side with respect to an intended scanning direction. When the edge of the document is to be detected, only one of the lamps is turned on to enhance the stripe pattern representative of the stepped edge portion of the document.

Claims

1. An image reading device comprising:

a document table for supporting a bound book document in a spread open position having an exposed inside area which is delineated in part by opposite side edges;

an image scanning mechanism having an image reading part for providing an image signal and an illumination part for providing an illuminated scanning sub-area,

said image scanning mechanism causing said image reading part, said illumination part, and said illuminated scanning sub-area to all move together in a scanning direction;

said illumination part including a plurality of light sources at least one of which is positioned downstream relative to the movement of the illuminated scanning sub-area in the scanning direction and at least one other of which is positioned upstream relative to the movement of the illuminated scanning sub-area in the scanning direction; and

a control arrangement for automatically controlling light output levels from said light sources such that at least at each of said opposite side edges, said illuminated scanning sub-area is formed by light impinging predominantly from a direction that will enhance shadows cast by said opposite side edges.

2. An image reading device as claimed in claim 1, wherein said controller further automatically controls the light output levels of said light sources to minimize any shadows being cast when said illuminated scanning area is moved over an inside binding area associated with the spread open bound book document.

3. An image reading device as claimed in claim 1, wherein said controller controls said light output levels of said light sources by limiting the amount of light that can be produced by an individual light source.

4. An image reading device as claimed in claim 3, wherein the limiting of the amount of light produced by said individual light source includes completely removing power from said individual light source.

5. An image reading device as claimed in claim 1, further comprising:

a side edge detecting device connected to said image reader part and responsive to said image signal to provide an output signal indicating detection of one of the side edges.

6. An image reading device as claimed in claim 5, wherein said edge indicating device output signal is provided to said scanning mechanism as a control signal producing a change in said scanning direction.

7. An image reading device as claimed in claim 1, further comprising:

a page turning mechanism for turning a page of the bound book document to expose a new inside surface area.