JP2007281703A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a ratio that enables reading without dust when there is dust in first priority-color data in a color CCD during monochrome mode reading in a DF mode. <P>SOLUTION: A scanning position of an image sensor is fixed at a prescribed position during DF mode reading, so as to read a DF background plate prior to original-manuscript reading. When there is dust in the first priority-color data during the monochrome mode reading, the monochrome mode reading is executed by using other-color data without dust. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an image reading apparatus such as a digital copy, a facsimile, and a scanner.
In particular, the apparatus is equipped with a BOOK mode reading in which an image sensor scans and reads an original placed on a contact glass, and a DF mode reading in which the scanning position of the image sensor is fixed and the original is moved by a sheet-through DF. In addition, the present invention relates to an image reading apparatus that can perform color reading using a color CCD (RGB 3-line CCD), and performs reading with one color data in the color CCD at the time of monochrome mode reading.

  Conventionally, in an image reading apparatus such as a digital copy, in the BOOT mode reading, since the image sensor scans and reads, even if dust adheres to the contact glass, it only affects the reading data of the dust position and is abnormal. However, in DF mode reading, since the scanning position of the image sensor is fixed and reading is performed, if dust adheres to the contact glass, the position of the dust is detected over the entire sub-scanning direction of the read image. The read data is affected, resulting in a vertical streak image. (In many cases, the image data becomes black due to dust, resulting in black vertical stripes.)

In order to solve the above problem, for example, in Patent Document 1, in DF mode reading, prior to reading a document, the DF background plate is read, and if a reading data abnormality due to dust is detected, the DF reading position is moved to detect dust. A technique is disclosed that provides a DF reading in which occurrence of vertical streak images is suppressed by searching for a position where there is no reading data abnormality due to, and performing DF reading at a position free of dust.
JP 2001-333253 A

  However, in the above-described conventional example, as described above, even in the method of moving the DF reading position when dust is detected, the dust detection continues, and if the movement is repeated, the time required for dust detection increases. Become slow. After all, the number of times dust detection is repeatedly performed is limited, and there are many cases where dust cannot be avoided.

  The present invention has been made in view of the above-described circumstances, and the object thereof is BOOK mode reading in which an image sensor scans and reads a document placed on a contact glass, and the scanning position of the image sensor is fixed. This is a device equipped with a DF mode reading for reading an original by moving it through a sheet-through DF, and is a device capable of color reading using a color CCD (RGB 3-line CCD). This invention relates to an image reading device that reads in color data. When reading in black and white mode in DF mode, if there is dust in the first priority color data in the color CCD, it is read in black and white using other color data without dust. Is to increase the ratio of reading without dust.

The image reading apparatus according to claim 1,
A device equipped with a BOOK mode reading in which an image sensor scans and reads an original placed on a contact glass, and a DF mode reading in which the scanning position of the image sensor is fixed and the original is moved by a sheet-through DF. In an image reading apparatus that can read a color using a color CCD (RGB 3-line CCD), and that reads in one color data of the color CCD at the time of black and white mode reading,
Dust determination means for determining whether there is dust at the scanning position from the read data of each color, and color data selection means for selecting one color data used for monochrome mode reading based on the determination result of each color,
At the time of DF mode reading, the scanning position of the image sensor is fixed at a predetermined position, and the DF background plate is read prior to reading the document.
It is an object of the present invention to perform dust-free reading by performing monochrome mode reading using other color data without dust when the first priority color data has dust during black-and-white mode reading.

The image reading apparatus according to claim 2,
The apparatus according to claim 1, wherein the first priority color and the second priority color used for black and white mode reading can be designated from the operation unit, and the priority color data used for black and white mode reading can be selected.

An image reading apparatus according to claim 3 is provided.
The apparatus according to claim 1 or 2, wherein when there is dust in the first priority color data by reading the DF background plate, the scanning position of the image sensor is moved and the dust determination is repeatedly performed. Another object of the present invention is to enable reading without dust by using other color data without dust when the first priority color data has dust.

An image reading apparatus according to claim 4 is provided.
3. The apparatus according to claim 1 or 2, wherein when the DF background plate is read and there is dust and no data can be selected, by moving the scanning position of the image sensor and repeatedly performing dust judgment, there is dust and usable data. The object is to enable reading without dust by moving the scanning position of the image sensor even in the absence of dust.

An image reading apparatus according to claim 5 is provided.
5. The apparatus according to claim 3 or 4, wherein the number of times of moving the scanning position of the image sensor can be specified from the operation unit, thereby preventing the presence of dust, repeated movement, and delaying the DF reading time. It is said.

An image reading apparatus according to claim 6 is provided.
6. The apparatus according to claim 3, wherein, when dust continues from the operation unit to the end, reading is performed using the data of the first priority color at the last image sensor scanning position. The purpose is to allow the user to select whether to give priority to reading or to give priority to high quality because reading can be stopped or specified.

  According to the present invention, when there is dust in the data of the first priority color in the color CCD at the time of black and white mode reading in the DF mode, black and white reading is performed using data of other colors without dust, The ratio at which dust-free reading can be performed can be increased.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram showing a scanner 13 as an image reading apparatus.

  In FIG. 1, a reading unit 12 and an SDF (sheet through document feeder) 20 attached to the upper part of the reading unit 12 are provided.

  The reading unit 12 includes a contact glass 1 for placing a document as a document table, a first carriage 6 including an illumination lamp 2 for document exposure, and a first mirror 3, and a second mirror 4 and a third mirror 5. It is composed of a second carriage 7, a lens unit 8 for forming an image on an image sensor (CCD) 9, a sensor board 10 on which the CCD 9 is mounted, and a reference white plate 11.

  When reading an original placed on the contact glass 1 (BOOK mode), the first carriage 6 moves at a constant speed and the second carriage moves at half speed in the direction of arrow A. The document on the glass 1 is scanned.

  Next, the configuration of the SDF 20 and the reading operation in the DF mode will be described.

  The originals 22 placed on the original tray 21 are sent to the separation unit by the pickup roller 23, separated one by one by the feed roller 24 and the separation roller 25, and conveyed. Thereafter, the document is conveyed by a conveyance drum 26 as a feed roller and a plurality of driven rollers 27 arranged around the conveyance drum 26 and pressed by the conveyance drum 26.

  On the other hand, the first and second carriages scan the reference white plate 11 and then stop at the scanning position shown in FIG. 1, and start reading the original when the original is conveyed.

  The document is conveyed to the right side of FIG. 1 by the conveyance drum 26 and the driven roller 27, and the reflected light incident on the CCD 9 is obtained by scanning the document in the sub-scanning direction. The read original is discharged to a discharge tray 29 by a discharge roller 28.

  FIG. 2 shows a configuration around the DF scanning position Y.

  At the DF scanning position Y, a DF contact glass 30 is provided facing the transport drum 26, and a DF background plate 31 is provided above the DF contact glass 30. (In this embodiment, the DF background plate is white.)

  If dust such as paper dust adheres to the DF contact glass 30, the scanning position does not move when the DF document is read, resulting in a vertical streak image.

  Next, read data processing will be described with reference to FIG.

  In the scanner 13, the CCD 9 is a color CCD in which three rows of CCD sensors covered with RGB filters are arranged. The analog processing unit 43 samples and holds the analog signal output from the CCD 9, amplifies the analog signal, and converts the RGB analog signals into digital signals by the A / D converter 44 and outputs the digital signal to the image processing unit 41.

  Since the signal output from the CCD 9 has a positional shift of 4 lines at the same magnification, the inter-line correction unit 45 delays the R color signal by 8 lines and the G color signal by 4 lines at the same magnification. Are read at the same position (line). The seeding correction unit 46 corrects the RGB non-uniformity of the optical system and sensitivity variations of the CCD 9 for each of the RGB signals, and outputs image data to the subsequent stage.

  Here, in the color reading mode, the subsequent image processing is performed on the RGB three-color data output from the seeding correction unit 46, but in the monochrome mode, the subsequent image processing is performed only on the G-color data.

  The operation of the apparatus of claim 1 will be described with reference to FIG.

  At the time of reading the DF mode, prior to reading the document, first, the reference white plate 11 is read to generate shading data that becomes a white reference level. Since the shading data is created by data of a plurality of lines read while scanning the reference white plate, even if there is dust on the reference white plate, the shading data is hardly affected by dust.

  After the creation of the shading data, the first carriage 6 moves to the DF scanning position Y in FIG. 2 and reads the DF background plate 31 prior to reading the document to determine whether or not each color data of RGB has dust. Judgment by

  Here, an example of the determination method of the dust determination means 51 will be described.

  The dust determination means 51 detects the MIN value and MAX value in the data read from the DF background plate 31 for each color. If the MIN value is less than a predetermined ratio with respect to the MAX value, the data is affected by dust. It is determined that

  The read data of the DF background plate 31 has a substantially uniform level due to the shading correction. However, if there is black dust, the read level decreases. If the MIN / MAX level is below a predetermined value, it can be determined that the read data is affected by dust.

  Data used by the CPU is determined based on the determination result of the dust determination unit 51 and a selection signal is output to the color data selection unit 52. The color data selection unit 52 switches data output to the G color line based on the selection signal. (Select and output one color of RGB)

  After the reading color is determined, the document image is read in synchronization with the conveyed document.

  In the operation of the apparatus of claim 2, the first priority color and the second priority color used for reading the monochrome mode can be designated from the operation unit, and the selection of the first priority color is essential. After that (second priority color, third color) cannot be selected.

  FIG. 5 is a flowchart illustrating an example of a flow for determining data to be used by the CPU based on the determination result of the dust determination unit 51. In the flowchart, the G color is fixed in the black-and-white mode of the BOOK mode, but it may be switched as in the DF mode.

  According to the operation of the apparatus of claim 3, if dust is present in the first priority color by reading the DF background plate, the DF scanning position is moved by a predetermined distance, and the dust determination is repeated with the position as a new DF scanning position.

  If dust continues to the first priority color even if the DF scanning position is moved a predetermined number of times, it is determined in the flowchart of FIG. 5 whether other colors can be used.

  Note that the predetermined number of scan position movements is different from the limit number of movements, and after the predetermined number of times, there is no choice even if there is dust in the flowchart of FIG. However, when there is no selected color, the DF scanning position is moved by a predetermined distance, and the dust determination is repeated with the position as a new DF scanning position.

  According to the operation of the apparatus of claim 4, from the beginning of the DF background plate reading, according to the flowchart of FIG. 5, if there is no selected color, the first priority color is unavoidably selected even if there is dust. When there is no color, the DF scanning position is moved by a predetermined distance, and the position is newly set as the DF scanning position, and dust determination is repeated.

  Since the range that can be used as the DF scanning position is limited, if the DF scanning position is moved to a limit position due to dust, the moving direction is reversed.

  The operation of the apparatus according to the fifth aspect can specify a predetermined number of times or a limited number of times for moving the DF scanning position from the operation unit.

  According to the operation of the apparatus of claim 6, when dust continues from the operation unit to the end, it is possible to specify whether reading is performed using the first priority color data at the last DF scanning position or reading is stopped. It has become.

  According to the above-described embodiment, the invention described in claim 1 is that the image sensor scans and reads a document placed on the contact glass, and the reading mode of the image sensor is fixed. This is a device equipped with DF mode reading that moves and reads a document by DF, and is a device capable of color reading using a color CCD (RGB 3-line CCD). In an image reading apparatus that performs reading, a dust determination unit that determines whether there is dust at a scanning position from data of each color that has been read, color data selection that selects one color data to be used for black and white mode reading based on the determination result of each color The scanning position of the image sensor is fixed at a predetermined position when reading the DF mode. When reading the F background plate and reading the black and white mode, if there is dust in the first priority color data, the black and white mode reading is performed using the other color data without dust, thereby enabling reading without dust.

  Further, the invention according to claim 2 is the apparatus according to claim 1, wherein the first priority color and the second priority color used for black and white mode reading can be specified from the operation unit, so that black and white mode reading can be performed. Priority color data to be used can be selected.

  The invention according to claim 3 is the apparatus according to claim 1 or 2, wherein when the DF background plate is read and dust is present in the first priority color data, the scanning position of the image sensor is moved to repeatedly perform dust judgment. Even if the device has been moved a predetermined number of times, if there is dust in the first priority color data, it is possible to read without dust by using other color data without dust.

  The invention according to claim 4 is the apparatus according to claim 1 or 2, wherein when the DF background plate is read and there is dust and no data can be selected, the dust detection is repeatedly performed by moving the scanning position of the image sensor. Even when there is dust and there is no usable data, the scanning position of the image sensor can be moved to read without dust.

  The invention according to claim 5 is the apparatus according to claim 3 or 4, wherein the number of times of moving the scanning position of the image sensor from the operation unit can be specified, so that dust continues, the movement is repeated, and the DF reading time is It can prevent slowing down.

  The invention according to claim 6 is the apparatus according to any one of claims 3 to 5, and when dust continues from the operation unit to the end, the data of the first priority color is obtained at the scanning position of the last image sensor. It is possible to select whether to give priority to reading or to give priority to high quality.

  Each of the above-described embodiments is a preferred embodiment of the present invention, and various modifications can be made without departing from the scope of the present invention. For example, it can be applied to a printer, a copy, and a fax.

  In addition, a process for realizing the function of the present apparatus may be performed by causing the apparatus to read and execute a program for realizing the function of the image reading apparatus in the above embodiment. Further, the program is transmitted to another computer system by a transmission wave via a computer-readable recording medium such as a CD-ROM or a magneto-optical disk, or via a transmission medium such as the Internet or a telephone line. Also good.

  Each of the above embodiments has been described with respect to a configuration in which each function of the apparatus is realized as a single computer system. However, the present invention can be applied to a configuration in which a plurality of apparatuses are added for each function. It is.

It is a scanner block diagram in embodiment of this invention. It is a figure which shows the structure of DF scanning position periphery in embodiment of this invention. It is a block diagram of read data processing in an embodiment of the invention. 1 is a block diagram of an image reading apparatus in an embodiment of the present invention. It is a flowchart of the color data determination in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Contact glass 2 Illumination lamp 3 1st mirror 4 2nd mirror 5 3rd mirror 6 1st carriage 7 2nd carriage 8 Lens unit 9 Image sensor (CCD)
10 sensor board 11 reference white plate 12 reading unit 20 SDF
21 Document Tray 22 Document 23 Pickup Roller 24 Feed Roller 25 Separation Roller 26 Conveying Drum 27 Followed Roller 28 Paper Discharge Roller 29 Paper Discharge Tray

Claims (6)

A device equipped with a BOOK mode reading in which an image sensor scans and reads an original placed on a contact glass, and a DF mode reading in which the scanning position of the image sensor is fixed and the original is moved by a sheet through DF, and read. In an image reading apparatus that can perform color reading using a color CCD, and reads in one color data of the color CCD at the time of monochrome mode reading,
From the data of each color read, dust determination means for determining whether there is dust at the scanning position, based on the determination result of each color, color data selection means for selecting one color data used for black and white mode reading,
At the time of DF mode reading, the scanning position of the image sensor is fixed at a predetermined position, and the DF background plate is read prior to reading the document.
An image reading apparatus that performs black and white mode reading using data of other colors without dust when the first priority color data includes dust during black and white mode reading.   The image reading apparatus according to claim 1, wherein the first priority color and the second priority color used for black and white mode reading can be designated from the operation unit.   When the DF background / black / white mode is read, if the DF background plate is read and the first priority color data contains dust, the image sensor scan position is moved and repeated dust determination is performed. 3. The image reading apparatus according to claim 1, wherein when the data of one priority color includes dust, black-and-white mode reading is performed using data of other colors without dust.   3. The dust detection is performed repeatedly by reading the DF background plate during DF mode / monochrome mode reading, and if there is dust and no data can be selected, the scanning position of the image sensor is moved. Image reader.   5. The image reading apparatus according to claim 3, wherein the number of times of moving the scanning position of the image sensor can be specified from the operation unit.   4. It is possible to specify whether reading is performed using data of the first priority color at the scanning position of the last image sensor or reading is stopped when dust continues from the operation unit to the end. 6. The image reading device according to any one of items 1 to 5.

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