JP2005295407A - Image reader, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader for reducing a cost without requiring a conventional original size detecting means. <P>SOLUTION: The reader comprises: a plurality of contact image sensors which are arranged in a direction orthogonal an original carrier direction, so as to identify the size of a carried original, based on a density difference between a part with printing and a part without it in the original; and an original size recognition means for recognizing the original size which is identified by the contact image sensors. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus, and more particularly to an image reading apparatus and an image forming apparatus having a contact image sensor.

As an example of the prior art, when reading a black and white image in an image reading apparatus, it is known that the LED lighting time for reproducing a black and white image is 1/3 of the lighting time for reading a color document (for example, Patent Document 1).
JP-A-10-56577

  However, the above conventional image reading apparatus reduces the LED lighting time of a contact image sensor for image reading (hereinafter referred to as CIS) used for a scanner or the like to 1/3, but is consumed as compared with the case where the LED is not lighted at all. There is a problem that it takes power.

The present invention has been made in view of the above circumstances, and uses a plurality of divided CISs to identify document size detection based on a density difference between a portion where a document is present and a portion where a document is not present. It is an object of the present invention to reduce the cost of the apparatus.
Another object of the present invention is to control the CIS LED that does not allow a conveyed original document to be lit when reading a small-size original width, thereby further improving the accuracy of the apparatus and saving power.

  In order to achieve such an object, the invention according to claim 1 is arranged in the document conveying direction and the perpendicular direction, and the size of the conveyed document is determined by the density difference between the printed portion and the unprinted portion of the document. A plurality of contact image sensors to be identified, and document size recognition means for recognizing a document size identified by the contact image sensor.

  According to a second aspect of the present invention, in the case of the first aspect of the invention, when the document size recognized by the contact image sensor is a small document, the LED of the contact image sensor in a place where the conveyed document does not pass is not lit. It is characterized by having contact image sensor control means for controlling as described above.

  According to a third aspect of the present invention, in the invention according to the second aspect, the close contact image sensor control means cuts off the energization of the close contact image sensor at the same time as the conveyed document passes through the close contact image sensor, and the close contact image sensor. The LED is controlled so as not to light up.

  According to a fourth aspect of the invention, in the third aspect of the invention, the contact image sensor control means lights three contact image sensors when the document widths of the small-size documents are A2 and A3, When the document width of the document of size is A4, control is performed so that one contact image sensor is turned on.

  According to a fifth aspect of the present invention, there is provided the image reading apparatus according to any one of the first to fourth aspects.

  According to the present invention, a plurality of contact image sensors that are arranged in the document conveying direction and the orthogonal direction, and that identify the size of the conveyed document based on the density difference between the printed portion and the unprinted portion of the document, By including the document size recognition means for recognizing the document size identified by the contact image sensor, it is possible to reduce the cost of the apparatus without requiring a conventional document size detection means.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  The application target of the image reading apparatus according to the embodiment of the present invention is preferably applied to a digital copying machine of the image forming apparatus, and more particularly to a copying machine in which the reading function is divided.

  FIG. 1 is a block diagram showing a configuration of an image reading apparatus according to an embodiment of the present invention. The image reading device shown in FIG. 1 recognizes the size of a transported document by executing and controlling a series of processes, a document insertion detection unit 11 that detects insertion of a document, a document registration detection unit 12 that detects the leading and trailing edges of a document. A system control board (document size recognition means) 10, a document reading control, a reading control circuit (CIS control means) 15 for controlling LED lighting of each CIS, a drive control circuit 13 for sending a document conveying signal, and document conveying A scanner driving device 14 that performs reading, a power source device 19 that supplies a power source for reading the document, and lighting the divided CIS 16-1 to 5 and the LED of each CIS 16.

  FIG. 2 is a simplified configuration diagram in the vicinity of the CIS 16-1 to 5-5. A configuration that is a feature of the present embodiment will be described with reference to FIGS.

  When the operator inserts a document from the insertion slot, the document is detected by the document insertion detection unit 11, the system control board 10 recognizes that the document has been inserted, and the scanner driving device 14 transports the document. The conveyed document is identified by the system control board 10 by identifying the size of the document based on the density difference between the printed portion and the unprinted portion of the document in the CIS 16-1 to CIS16-1.

  The recognized original is returned by the scanner driving device 14, the front end of the original is recognized by the original registration detection unit 12, and the original is conveyed again. The conveyed document is irradiated by the divided LEDs of CIS 16-1 to 5, and the reflected light is imaged on CIS 16-1 to 5 to read the document image information.

  The formed original image is converted into an analog signal, and this analog signal is amplified by an image amplifying circuit (not shown) in the CIS reading control circuit 15, and the amplified analog signal is converted by the A / D conversion circuit for each pixel. Is converted into a multi-value digital signal.

  The converted digital signal corrects distortion due to unevenness in light amount, contact glass contamination, sensor sensitivity unevenness, and the like from a synchronization control circuit (not shown). The corrected digital image information is converted into digital recording image information by the image processing circuit 17 and then written in the image memory unit 18.

  As described above, the configuration of the present embodiment is not a configuration having a document detection unit as in the prior art, and can be configured at low cost.

  FIG. 3 is a flowchart illustrating the operation of the image reading apparatus having the above-described configuration as the first embodiment. When an operator inserts a document into a digital copying machine or the like and the document insertion detection unit 11 detects the document insertion, the document is conveyed. The CIS 16-1 to 5 identify the size of the conveyed document, and the system control board 10 recognizes the document size. At this time, if the system control board 10 recognizes that the document width is A4 (FIG. 3, S1 / YES), the reading control circuit 15 controls each CIS, and the central part of the divided CIS. Power is supplied only to the CIS16-3, and the other CIS16-1,2,4,5 are shut off (FIG. 3, S2), and the LED of the CIS16-3 is turned on.

  In S4, when the system control board 10 recognizes that the document width is A2 or A3 (FIG. 3, S4 / YES), the reading control circuit 15 supplies power to the divided CISs 16-2, 3, and 4. Thus, the power supply device 19 is controlled so that the LED is turned on. Further, the reading control circuit 15 performs control so that the power sources of the other CISs 16-1 and 5 at both ends are shut off (S5).

  In S4, when the system control board 10 recognizes that the document width is wider than A2 or A3 (FIG. 3, S4 / NO), the reading control circuit 15 turns on all the LEDs of the CIS 16-1 to 5 (see FIG. 3). S6).

  As described above, the operation of the first embodiment is controlled so that power is not supplied to the CIS if the document width is other than the A1 and A0 widths, so that power saving can be realized.

  FIG. 4 is a flowchart illustrating the operation of the image reading apparatus having the above-described configuration as the second embodiment. An operator inserts a document into a digital copier or the like, and CIS 16-1 to 5 identify the size of the document based on the density difference between the printed portion and the unprinted portion of the document, and the system control board 10 recognizes the document size. To do. Then, the scanner driving device 14 returns the document, and the document registration detection unit (document registration sensor) 12 recognizes the leading edge of the document. Then, as the document is conveyed and the document disappears from the document registration detection unit 12 (S11, YES), the reading control circuit 15 turns off the document registration detection unit 12 and X seconds after the document registration detection unit 12 Control is performed to turn off the LEDs of the CIS 16-1 to 5 (S12). At this time, the LED that is turned off according to the document size width remains off.

  As described above, according to the operation of the second embodiment, further power saving can be realized.

  As described above, according to the embodiment of the present invention, the image reading apparatus includes a plurality of CISs arranged in the document conveyance direction and the orthogonal direction in the document reading unit that reads the conveyed document, and the document is printed. By providing a means for recognizing the density difference between a portion and a portion not printed by CIS and recognizing the identified document size, the conventional document size detection means is not required, and the cost of the apparatus is reduced. Can do.

  Further, according to the embodiment of the present invention, when the document width recognized by the CIS is a document of a small size (A2, A3, A4), control is performed so that the LED of the CIS through which the conveyed document does not pass is not lit. By having the CIS control means, power saving can be realized as compared with the case where all the CIS LEDs are turned on regardless of the document size.

  In addition, according to the embodiment of the present invention, the CIS control means controls so that the CIS is turned off and the CIS LED is not turned on at the same time as the conveyed document finishes passing through the CIS. Compared with the case where the CIS LED is not turned on after the document has passed through all the CISs, power saving can be realized.

  As mentioned above, although the Example of this invention was described, it is not limited to the said Example, A various deformation | transformation is possible in the range which does not deviate from the summary.

1 is a block diagram illustrating a configuration of an image reading apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating a CIS configuration of an image reading apparatus according to an embodiment of the present invention. It is a flowchart which shows operation | movement of Example 1 of this invention. It is a flowchart which shows operation | movement of Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 System control board 11 Document insertion detection part 12 Document registration detection part 13 Drive control circuit 14 Scanner drive device 15 Read control circuit 16-1, 2, 3, 4, 5 CIS (contact image sensor)
17 Image Processing Circuit 18 Image Processing Memory Unit 19 Power Supply Device

Claims (5)

A plurality of contact image sensors that are arranged in a document conveying direction and a perpendicular direction, and that identify a size of a conveyed document by a density difference between a printed portion and a non-printed portion of the document;
Document size recognition means for recognizing the document size identified by the contact image sensor;
An image reading apparatus comprising:   In the case where the document size recognized by the contact image sensor is a document of a small size, it has contact image sensor control means for controlling not to turn on the LED of the contact image sensor in a place where the transported document does not pass. The image reading apparatus according to claim 1.   The contact image sensor control means controls to prevent the LED of the contact image sensor from being turned on at the same time that the conveyed document has passed through the contact image sensor, and at the same time, the contact image sensor is deenergized. The image reading apparatus according to claim 2, wherein:   The contact image sensor control means lights three contact image sensors when the document width of the small-size document is A2 and A3, and when the document width of the small-size document is A4, The image reading apparatus according to claim 3, wherein one of the contact image sensors is controlled to light up.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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