JP2003018363A - Image reader and image reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read documents comprising mixed black/white and color originals at a high-speed in an image reader that reads the documents fed by an ADF(automatic document feeder). SOLUTION: The image reader comprises an optical read means placed at a prescribed read position under a platen to read documents on the platen, a carrying means that can feed again the same document to the read position, an identification means that identifies the type of image data of the document read by the optical read means, and a control means that controls each means above. The control means discharges the document when the image data are of a 1st type and outputs the first image data in a 1st read mode, or feeds the document again to the read position when the image data are of a 2nd type to read the document in a 2nd read mode different from the 1st read mode as its control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus and an image reading method for reading an original moving on a platen with an automatic ADF, and more particularly to an image capable of reading not only a monochrome original but also a color original. The present invention relates to a reading device and an image reading method.

[0002]

2. Description of the Related Art In recent years, with the widespread use of personal computers capable of color rendering, the Internet, electrophotography, etc., there is an increasing demand for copying, printing or transmitting a color image which is much more expressive than a monochrome image. Is coming. Therefore, even in the image reading apparatus, it is required to read a color original at higher speed and more precisely than ever before.

However, when the image reading apparatus reads a color original, it usually has three primary colors of light, R (red) and G.
Since it is necessary to read image data for each of (green) and B (blue), when a color document is read with the same resolution as when reading a monochrome image, the reading speed is slower than when reading a monochrome document. Must.

On the other hand, the original read by the image reading device is
In some cases, color originals and black-and-white originals are mixed, and in such a case, if the uniform reading is performed in the color reading mode, the reading speed at the time of reading the black-and-white original will be reduced.

Therefore, in the prior art, when reading an original, the optical reading means first performs a pre-scan for determining whether the original to be read is monochrome or colorized, and in accordance with this determination, the original is black and white. There is known a so-called pre-scan / main-scan reading method in which a black-and-white reading mode of relatively high-speed scanning is read if it is present, and a color original is read if it is a color original.

On the other hand, an image processing apparatus described in Japanese Patent Laid-Open No. 9-261417 is known as an improved version of the prescan / main scan method which requires such two document passes. This apparatus mounts a circulation type document feeder on a reading device, moves the document to a reading position in advance, and circulates in the device to determine whether all pages of the document to be read are a monochrome document or a color document, and The determination result is stored for each page of the original, and when the original is actually read, in the case of a black and white original, high-speed scanning is performed by scanning while reading the original while fixing the optical reading means, and in the case of a color original, The document is fixedly arranged on the platen, and scanning is performed while moving the optical reading means to perform precise image reading.

Further, in Japanese Patent Laid-Open No. 2000-24850, it is set in advance whether an original is read in a color reading mode or a black-and-white reading mode, and whether the original is a monochrome original or a color original is determined by a color discriminating means in the original feeding device. Discriminate,
A document reading device that attempts to read a document whose determination result matches the setting mode is disclosed.

[0008]

However, in the case of the above-described prescan / main scan type image reading apparatus, a prescan for determining whether the original is a color original or a black and white original before the main scanning for image reading. As a result, the image reading time of the entire original in which the color original and the black-and-white original are mixed is not shortened so much.

The apparatus disclosed in Japanese Patent Application Laid-Open No. 9-261417 also relates to a kind of prescan / main scan method, in which an original is moved to a reading position in advance and circulated in the apparatus before the main scan. Since it is necessary, there is a limit to the reduction of the image reading time of the entire document.

Further, in the case of Japanese Patent Laid-Open No. 2000-24850, when the color reading mode is set, when a black-and-white original is mixed in a color original, the black-and-white original is not read and is discharged as it is. Since the paper is printed, it is necessary to take out the black and white original from the discharged original, set the black and white reading mode this time, and perform the reading start operation again. Considering the time required for such an operation, the reading time of the entire document is not shortened as a result.

The present invention has a function of discriminating between a color original and a black-and-white original when reading an original in which a color original and a black-and-white original are mixed. The present invention provides a document reading device and a document reading method that enable high-speed reading of the entire document when performing.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and is arranged at a predetermined reading position under the platen for reading a document moving on the platen. The optical reading means, and a conveying means capable of re-feeding the same document to the reading position,
The optical reading unit includes an identification unit for identifying the type of image data of a document read by the optical reading unit, and a control unit for controlling each unit. When the type is the type, the original is ejected and the image data in the first first reading mode is output, and when the image data is the second type, the original is re-fed to the reading position. Then, an image reading apparatus is provided, which is controlled to read in a second reading mode different from the first reading mode.

In the present invention, the re-feeding does not mean that the document is ejected even if the document is conveyed in the ejection direction and then the document is circulated and fed again to the reading position. Alternatively, the sheet may be fed back in the upstream direction and fed again to the reading position.

Here, the first reading mode is a mode for reading a monochrome image, and the second reading mode is a mode for reading a color image. Further, the first reading mode is a mode for reading a binary gradation image, and the second reading mode is a mode for reading a multi-value gradation image.

Thus, in the present invention, for example, in the case of reading a black-and-white original, the image data acquired in the first reading operation can be used as it is, so that the main scan is not necessary and the original in which the black-and-white original and the color original are mixed is not necessary. It enables high-speed reading of the set.

Further, according to the present invention, the same document can be re-fed to the reading position with the optical reading means arranged at the predetermined reading position under the platen for reading the document moving on the platen. And a control means for controlling each of the above-mentioned means, wherein the conveyance means is capable of carrying, an identification means for identifying whether the image data read by the optical reading means is monochrome data or color data, While the optical reading unit scans the document in the monochrome reading mode, the control unit stops the monochrome mode reading of the document when the identification unit identifies the image data of the document as color data. The present invention provides an image reading apparatus, characterized in that the original is re-fed onto the platen and read in a color reading mode.

In this case, in the re-feeding, the original is fed back in the upstream direction opposite to the paper discharge direction and fed again to the reading position. As a result, the present invention makes it possible to further speed up the reading of a document set in which a monochrome document and a color document are mixed.

Further, according to the present invention, in the original reading method for reading the image data of the original on the platen by the optical reading means arranged at the predetermined reading position under the platen, the original is read in the first reading mode. A step of identifying the type of the image data read in the first reading mode, and when the type of the image data is identified as the first type, the original is ejected and the first document is ejected. And outputting the image data in the first reading mode, and when the type of the image data is identified as the second type, the original is re-fed to the reading position and the first first reading mode is set. Provides an image reading method characterized by being constituted by each step of reading in a different second reading mode.

Further, according to the present invention, a step of reading an original in a monochrome reading mode, a step of identifying whether or not the image data read in the monochrome reading mode is monochrome data, and a type of the image data Is black and white data, the step of outputting the image data, and if the image data is identified as color data, the step of stopping scanning of the original in the black and white mode; The present invention provides an image reading method characterized by comprising the steps of re-feeding the document to the reading position and scanning the document in the color reading mode.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific examples of embodiments of an image reading apparatus and an image reading method according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a first image reading apparatus according to the present invention.
FIG. 3 is a cross-sectional view showing an automatic document feeder (hereinafter, referred to as “ADF”) and a reading device of the embodiment example. As shown in FIG. 1, the image reading apparatus according to the first embodiment of the present invention is
An F1 and a reading device 2 are provided. FIG. 2 is a view showing the document transport mechanism of the ADF 1.

The ADF 1 is mounted on the reading device 2 and conveys a document so as to pass over the upper surface of the first platen 3 of the reading device 2.

The reading device 2 includes a first platen 3 (FIG. 2).
An image sensor, which is a reading means such as a CCD, irradiates a conveyed original document with light from a light source 4 such as a lamp, and reflects the reflected light by a plurality of mirrors 5 to form an image by a condenser lens 6. Read the image of the document by. That is,
The first platen 3 serves as the reading position (reading unit) of the reading device 2. The reading device 2 also includes a second platen 8 having an area where the entire surface of the document can be placed. The reading device 2 is A
DF1 is opened and closed to read a thick original such as a book placed on the second platen 8 with the first carriage 50 and the second carriage 51 of the reading carriage including the light source 4 and the condenser mirror 5 in the sub-scanning direction. Second by moving to
It is also possible to read the image of the original through the platen 8 of FIG.

The ADF 1 includes a paper feed tray 9 on which a plurality of originals are placed, a paper feed means 10 for feeding the originals placed on the paper feed tray 9 one by one to a reading position, and the reading. And a paper discharge tray 11 for storing the documents discharged from the position.

Further, the ADF 1 is continuous with the paper feed path 16 for feeding the originals on the paper feed tray 9 one by one toward the reading position on the first platen 3. A conveyance path 17 for guiding the formed original document along the upper side of the first platen 3, and a delivery tray 11 from the conveyance path 17.
The first paper discharge path 18 connected to the paper discharge port of
A circulation path 19 that is connected to the connection portion between the paper feed path 16 and the transport path 17 from the first paper discharge port and returns the original document to the transport path 17 again
An intermediate path 20 that is formed by branching from the paper discharge path 18 and guides a document from the transport path 17;
A switchback path 22 for switching back the original document and reversely conveying the original document. The switchback roller 40 performs a switchback that reversely rotates in a state where the rear end of the document is nipped and switches the traveling direction of the document back and forth in the double-sided mode for reading images on both sides of the document. The platen 3 is controlled to be conveyed to the reading position. Further, the ADF 1 suspends the reading during the reading of the original, stops the feeding of the original, reversely rotates the feeding roller 31 to switch back, and feeds back the fed-back original when feeding back in the direction of the discharge tray. Have As described above, the document conveying means in this apparatus has a function of re-feeding the document to the reading position in a predetermined manner. In this way, re-feeding means feeding an original in the paper ejection direction, circulating the original, and feeding the original again to the reading position, and feeding back the original in the upstream direction opposite to the paper ejection direction. This means that the sheet is conveyed and fed again to the reading position.

In the paper feeding path 16, a feeding roller 26 for feeding the original, a feeding roller 28 for feeding the original fed by the feeding roller 26, and only the uppermost original is fed by the feeding roller 28. A separation member 29 for preventing the feeding of the second and subsequent originals and a pair of registration rollers 30 for feeding the originals fed by the paper feed roller 28 to the downstream side after aligning the leading ends thereof are arranged. There is.

Feeding roller 26 and paper feeding roller 28
Is connected to the paper feed motor M1 via a one-way clutch OW1. The registration roller 30 is connected to the paper feeding motor M1 via a one-way clutch OW2. As a result, the paper feed motor M1 rotates the feeding roller 26 and the paper feed roller 28 by the normal rotation of the drive shaft, and rotates the registration roller 30 by the reverse rotation of the drive shaft.

The conveying path 17 has a large-diameter conveying roller 31.
And a plurality of driven rollers 32, 33, 34 which are pressed against the outer peripheral surface of the transport roller 31. The transport roller 31 is a transport motor M2 capable of forward rotation and reverse rotation.
Driven by.

A driven roller 36, which is in pressure contact with the conveying roller 31, and a pair of paper discharge rollers 37 for discharging the original document to the paper discharge tray 11 are arranged in the paper discharge path 18. The paper discharge roller 37 is connected to a paper discharge motor M2 that can rotate in the normal and reverse directions. Further, as described above, the switchback path 22 is formed below the paper discharge path 18. A pair of switchback rollers 4 on the switchback path 22
In the case of 0, one switchback roller 40 is separated from the other switchback roller 40 by the pressure contact solenoid SOL3 so that the originals circulated through the circulation path 19 and the conveyance path 17 can be conveyed without any trouble when the front and rear ends pass each other. Is configured. Switch back roller 4
0 is connected to a paper discharge motor M1 that can rotate in the forward and reverse directions.
Further, above the discharge path 18, when the document identifying unit identifies the color of the document reading surface and determines to re-read, the control unit instructs the interruption of the reading of the document, and the large-diameter conveying roller 3 is provided.
An evacuation path 80 is provided to evacuate the document 1 fed back by rotating 1 in reverse.

A paper discharge path 18 is provided on the downstream side of the transport path 17.
Alternatively, a second flapper 42 for guiding to either one of the switchback paths 22 is arranged. The second flapper 42 is driven by the second solenoid SOL2. Further, in the evacuation route 80 above the paper ejection route 18,
A dead-weight flapper 43 is arranged which moves upward by the trailing end of the document to be fed back and guides the document to the evacuation path, and moves downward when the trailing end of the document passes.

The empty sensor S1, the lead sensor S2, the paper discharge sensor S8, the switchback sensor S5 and the like for detecting the presence / absence of a document from the paper feed tray 9 are connected to a control device (control means). Further, the paper feed motor M1 and the transport motor M2 are connected to a control device (not shown). The pressure contact solenoid SOL1, the second solenoid SOL2, and the third solenoid SOL3 are also connected to the control device. The control device has a central processing unit (CPU) or the like for controlling the document conveyance.

With this control device, the sensors S1 to S
The motors M1 and M2 and the solenoids SOL1 to SOL3 are controlled on the basis of the output signal from 8 and the document identifying means, and the above document transport operation is executed.

Next, details of the ADF 1b and the reading device 2b as the second embodiment of the device according to the present invention will be described with reference to FIGS.

As shown in FIG. 3, an image reading / reading apparatus as a second mode of the present apparatus is an ADF 1b and a reading apparatus 2.
b.

FIG. 4 is a diagram showing an ADF document transport mechanism. The ADF 1b is mounted on the reading device 2b.
The ADF 1b conveys the document so as to pass over the upper surface of the first platen 3 of the reading device 2b.

The optical reading means built in the reading device 2b comprises a light source 4, mirrors 5a, 5b, 5c, a condenser lens 6 and an image sensor 7 in one carriage 55. When reading the image data of the original carried in by the ADF 1b, the carriage 55 is mounted on the first platen 3
The light source 4 located below and along the main scanning direction of the document, and the light emitted from the light source 4 are applied to the document surface, and the reflected light is reflected by the first mirror 5a, the second mirror 5b, and the third mirror 5a. Mirror 5
It is configured such that the light is sent to the condenser lens 6 by c and the light focused by the condenser lens 6 is received by the image sensor. When a thick original such as a book is read, as shown in FIG. 3, the optical reading means in which the light source, the mirror, the condenser lens 6 and the image sensor 7 are mounted on one carriage 55 is the second platen 8. The image data on the document surface is read while moving from the left side to the right side (sub scanning direction) of the drawing. The image data received by the image sensor 7 is normally converted into a digital signal in the reading device 2b and then sent to the image forming apparatus G such as a copying machine.

The ADF 1b is a sheet feeding means for feeding out the originals placed on the paper feed tray 9 one by one and feeding them in a predetermined paper feeding direction, and feeding the fed originals while rotating them. The image reading unit located below the tray 9 is provided with a conveying unit for passing over the platen 3 and a sheet discharging unit for discharging a document that has passed over the platen 3 to a sheet discharging tray 11. The ADF 1b is rotatably supported at the downstream end in the paper feed direction, and the paper feed means, the transport means, and the paper discharge means have two drive motors M1, M.
Driven by two.

Further, the ADF 1b is connected to the paper feed path 16 for feeding the originals on the paper feed tray 9 one by one toward the reading position on the first platen 3 and the paper feed path 16. A conveyance path 17 that guides the formed document along the upper side of the first platen 3, and the discharge tray 1 from the conveyance path 17.
And a paper discharge path 18 connected to the first paper discharge port.

In the paper feeding path 16, a feeding roller 26 for feeding the original, a paper feeding roller 28 for feeding the original fed by the feeding roller 26, and only the uppermost original is fed by the paper feeding roller 28. A separation member 29 for preventing the feeding of the second and subsequent originals and a pair of registration rollers 30 for feeding the originals fed by the paper feed roller 28 to the downstream side after aligning the leading ends thereof are arranged. There is.

Feeding roller 26 and paper feeding roller 28
Is connected to the paper feed motor M1 via a one-way clutch OW1. The registration roller 30 is connected to the paper feeding motor M1 via a one-way clutch OW2. As a result, the paper feed motor M1 rotates the feeding roller 26 and the paper feed roller 28 by the normal rotation of the drive shaft, and rotates the registration roller 30 by the reverse rotation of the drive shaft.

In the conveying path 17, conveying rollers 39a, 3
9b is arranged. The transport rollers 39a and 39b are
It is driven by a transport motor M2 capable of forward rotation and reverse rotation.

The paper discharge roller 37 is connected to a paper discharge motor M2 capable of rotating in the forward and reverse directions. The paper discharge roller 37 is reversely rotated in a state where the rear end of the document is nipped in the double-sided mode in which images on both sides of the document are read, so that the document is switched back and sent to the conveyance path 17 via the circulation path 19. Controlled. Further, the pair of paper discharge rollers 37 presses the solenoid SO so that the originals circulated through the circulation path 19 and the conveyance path 17 can be conveyed without any trouble when the front and rear ends of the originals pass each other.
One paper discharge roller 37 is configured to be separated from the other paper discharge roller 37 by L1. Further, the paper discharge path 18 and the paper discharge roller pair 37 have a function of performing a switchback for switching the traveling direction of the document back and forth. At the time of reading a document, when the document identifying unit identifies the document reading surface and determines to re-read (for example, change from the monochrome reading mode to the color reading mode), the control unit
The reading of the original is interrupted, and the original is conveyed to the paper discharge path 18. The document conveyed to the paper ejection path 18 is ejected by the paper ejection roller 37.
Is reversely rotated to be conveyed back to the circulation path 19 and re-conveyed to the first platen 3 via the conveyance path 17. In the process of this re-conveyance, the front side and the back side of the document are reversed and the back side is read. Therefore, in order to re-read the surface of the original for which reading has been interrupted, the original is conveyed again from the conveying path to the paper discharge path, is switched back again, and is returned to the reading position of the platen 3 via the circulation path 19. It will be fed. When the document is re-fed and set at the reading position of the platen 3 in this manner, the document is conveyed at a controlled speed (for example, a slow speed in the color reading mode) to be re-read. There is.

An empty sensor (not shown), a lead sensor S2, a paper discharge sensor (not shown), a switchback sensor (not shown) and the like are connected to a control device (control means). Further, the paper feed motor M1 and the transport motor M
2 is connected to a control device (not shown). The pressure contact solenoid SOL1 is also connected to the control device.
The control device has a central processing unit (CPU) or the like for controlling the document conveyance.

With this control device, the motors M1 and M are driven based on the output signals from the sensors S2 and the document identifying means.
2 and the respective solenoids SOL1 are controlled to execute the document conveying operation.

Next, details of the image reading method according to the present invention will be described.

First, a method of identifying whether a read image is a monochrome image or a color image will be described. FIG. 5A is a diagram showing a spectral sensitivity characteristic showing a relationship between relative sensitivity and wavelength in color identification of each sensor, and FIG. 5B is a diagram showing spectral reflection data of a black and white document. As shown in FIG. 5A, at the reading levels of the red line sensor, the green line sensor, and the blue line sensor, the peaks of the spectral sensitivity peaks of the respective line sensors are red (R), green (G), and blue. Since (B) is different, the wavelength of the peak value of the output of each line sensor is different when the color original is read. On the other hand, as shown in FIG. 5B, in the case of a black-and-white original, the spectral reflectance is constant regardless of the wavelength, and each line sensor has a sensor output that is uniformly high with respect to white pixels. It shows a uniformly low sensor output for the pixel. As a result, whether the read document is a color document or a monochrome document is identified or determined. In this way, to identify the original,
It should be noted that it is possible to discriminate based on the image data read by the high-speed reading in the black-and-white reading mode because it is only necessary to check whether or not the wavelength of the peak value of the output of the line sensor of each color is different. Should be.

In the present invention, the color determination unit receives the outputs from the red line sensor, the green line sensor, and the blue line sensor, which have been converted into digital signals, from the shading correction unit, which will be described later. If there is no difference, it is determined to be a black and white original.

In the present embodiment described below, the data memory unit 107 (FIGS. 7 and 8) for sequentially storing the image data read by the reading means in the image signal control device (hereinafter referred to as "control device"). The example provided in () is described. However, depending on the type of the image reading apparatus, there is a type that does not have a data memory for storing the image data and outputs the image data from the reading unit to the image forming apparatus side after correction processing. In such a case, in the application of the present invention, the discriminating means for discriminating the type of the image data, that is, the monochrome data or the color data, is performed based on the correction signal of the image data from the reading means.

In FIG. 6, in addition to three sensors for red (R), green (G) and blue (B), a black and white (B / W) sensor is provided.
1 shows a circuit configuration of a control device 100 using a line sensor of a book. In FIG. 6, the control device 100 includes four line sensors 102W, 102R, 1 for reading a document.
02G, 102B and A / D conversion unit 1 for converting analog data read by the line sensor into digital data
03, a shading correction unit 104 that performs shading correction (sensitivity correction between photoelectric conversion elements) on the converted data, a color determination unit 106 that determines the gradation of the shading-corrected data, and a result determined by the color determination unit. In response to this, a control control unit 108 that outputs a signal for controlling the reading of the image reading apparatus, a selector unit 105 that switches to monochrome data or color data by the SEL signal from the control control unit 108, and outputs, and a control control unit 108 The data memory unit 107 switches the data to black-and-white reading or color reading by the SEL signal, stores the data, and outputs the data to the image forming apparatus. In the case of the control circuit shown in FIG. 6, the image data in the first reading mode (black and white reading mode) uses the image data read by the black and white sensor 102W, but at the same time, the green sensor 102G and the red sensor 102R are used. It also discriminates whether the document is a color document or a monochrome document based on the output of the blue sensor 102B.

FIG. 7 shows an image signal control section 100b using three line sensors for red (R), green (G) and blue (B).
Therefore, the image signal control unit 100b uses the licensor 102
R, 102G, 102B, an A / D conversion unit 103 for converting analog data read by the line sensor into digital data, a shading correction unit 104 for shading correction of the converted data, and a shading correction based on the data. A monochrome mix conversion unit 109 that generates a black signal, a color determination unit 106 that determines the gradation of the shading-corrected data, and a signal that controls the image reading apparatus to control the reading based on the result determined by the color determination unit. A control control unit 108 for outputting and a selector unit 105 for switching and outputting to monochrome data or color data by a SEL signal from the control control unit 108.
And a data memory unit 107 which switches read data to black-and-white reading or color reading by the SEL signal from the control control unit 108, stores the data, and outputs the data to the image forming apparatus. Therefore, in the case of the control circuit shown in FIG. 7, the image data in the first reading mode (black-and-white reading mode) includes the green sensor 102G and the red sensor 10.
It becomes the AND value of the outputs of 2R and the blue sensor 102B. Then, based on whether there is a difference in the output pattern of the green sensor 102G, the red sensor 102R, and the blue sensor 102B, it is discriminated whether it is a color original document or a black and white original document.

Next, an example of a document reading control flow in this embodiment will be described.

When the document is read by the image reading apparatus (S1), the operator sets the reading mode based on FIG. 8 (S2). If the color reading mode is set (S3), the low-speed color image mode (25
Image reading is performed at CPM / 108 mm / sec). If the monochrome reading mode is set (S5),
High-speed black-and-white reading mode (50 CPM / 216 mm / se
The image reading according to c) is performed. When the automatic color select (ACS) mode is set (S4)
Then, the following read operation control according to the present invention is executed.

FIG. 9 shows the first image reading operation according to the present invention.
2 is a flowchart of a control method for determining the mode of the read image data after the completion of reading the original in the first reading mode (moving reading mode).

FIG. 10 relates to the second control method of the image reading operation according to the present invention, and shows a flowchart of the control method for discriminating the mode of the image data step by step during the reading of the original.

In FIG. 9, after the original is placed on the paper feed tray, the reading operation is started (S10). Where A
When the start key of the image reading apparatus is pressed after the CS mode is set (S11) (S12), document feeding is started by the ADF 2. The document is fed to the reading position 3 and the reading device 1 starts the reading operation in the first reading mode (S13). The data read in the first reading mode is stored in the memory as the first type of data (black and white data) (S14). The stored data corresponds to the line CCD sensor 1 as described in FIG. 6 or 7.
The analog signal of the document read by 02 is A / D converted by the A / D conversion unit 103, and is also subjected to shading correction by the shading correction unit 104, and then the selector unit 105.
The image data output to.

The first reading of the document is completed (S
15), the color determination unit 106 identifies the type of the stored image data (S17). Here, when it is identified as the first type (black and white data), the data memory 107
The image data stored therein is output to the image forming apparatus side (S16), and the image reading of the document is completed. Then, the document is discharged to the discharge path 18.

Next, when the image data stored in the data memory 107 is identified as the second type (color image) (S17), the reading mode of the apparatus is set to the first reading. Change to the second reading mode (color reading mode) for reading at a lower speed than the mode (S18),
The image data (black and white data) in the first reading mode in the data memory unit 107 which has already been read and stored as black and white data is deleted (S19). Then, the document is re-fed to the reading position 3 by the transport roller 31 (S20). This re-feeding is performed by the circulation path 19
May be carried out by circulating the paper, or by feeding back in the direction opposite to the paper discharge direction.

When the document is re-fed to the reading position 3 in this way, re-reading of the document is started at the slower speed of the second reading mode (color reading mode) (S21).
The read image data (color image data) of the document is sequentially stored in the data memory 107 (S2).
2). When the original is continuously read, the original reading operation (S21, S
22) is continued, and when the reading of the document in the second reading mode is completed (S23), the color image data in the memory 107 is output to the image forming apparatus side (S2).
4). Then, the above-described reading operation control is performed for all the originals placed on the paper feed tray 9 (S).
25, S26).

FIG. 10 shows an example of the second image reading operation control of the present invention. Here, unlike the above-described second control method, it is determined whether the data is black-and-white data or color data during document reading.

In FIG. 10, after the document is placed on the paper feed tray, the reading operation is started (S30). When the start key of the image reading apparatus is pressed after the ACS mode is set (S31) (S32), the ADF 2 starts feeding the document. The document is fed to the reading position 3 and the reading device 1 starts the reading operation in the first reading mode (S33).

The data read in the first reading mode is stored in the memory as the first type of data (black and white data) (S34). The stored data is stored in the line CCD sensor 10 as described in FIG. 6 or 7.
The analog signal of the document read by 2 is image data that is A / D converted by the A / D conversion unit 103, shading corrected by the shading correction unit 104, and output to the selector unit 105.

Next, in the example of the second image reading operation control, unlike the above-described example of the first image reading operation control, the image data sequentially read during the image reading of the document is the first. It is identified whether it is the first type (black and white data) or the second type (color data) (S35).
Then, when it is identified as the first type (black and white data) (S36), the reading in the first reading mode is continued (S38). If all the image data of the document is identified as the first type (black and white data) (S36), the image data stored in the data memory 107 is output to the image forming apparatus side (S38). Then, the image reading of the document is completed, and the document is discharged to the discharge path 18.

However, when the image read data of the document is identified as the second type (color image) (S35), the first read mode (black and white read mode).
Immediately stop the reading in (S37), change the reading mode of the apparatus to the second reading mode (color reading mode) for reading at a lower speed than the first reading mode (S39), and The image data (black and white data) read in the first reading mode and stored in the data memory 107 until the time point is deleted (S40).

Then, the document is re-fed to a predetermined reading position by the transport roller 31 (S4).
1). This re-feeding may be performed by circulating the circulation path 19, or may be performed by feeding back in the direction opposite to the paper discharge direction.

In this way, when the original is re-fed to the predetermined reading position, re-reading of the original is started at the slow speed of the second reading mode (color reading mode) (S4).
2). The read image data (color image data) of the document is sequentially stored in the data memory 107 (S4).
3). When the reading of the document in the second reading mode is completed (S44), the color image data in the memory 107 is output to the image forming apparatus side (S45). When the document is continuously read, the document reading operation (S21, S22, S
23) is repeated until the end of the read document. When the reading of one document is completed, the color image data is output from the memory 107 to the image forming apparatus side (S24). The above-mentioned reading operation control is performed for all the originals placed on the paper feed tray 9 (S27).

As described above, in the image reading apparatus according to the present invention, the same document is read by the optical reading unit arranged at a predetermined reading position under the platen for reading the document moving on the platen. A transporting means capable of re-feeding the sheet to a position, an identifying means for identifying the type of image data of the original read by the optical reading means, and a control means for controlling the respective means. If the image data is of the first type, the control unit ejects the document and outputs the image data in the first first reading mode, and the image data is of the second type. If there is, the original is re-fed to the reading position, and is read and output in the second reading mode different from the first reading mode.

As a result, according to the present invention, in the image reading apparatus adapted to read a document traveling by the ADF, the image data obtained in the first reading operation can be used as it is in the reading of a black-and-white document. It became unnecessary and realized high-speed reading of a document set in which black and white documents and color documents were mixed.

[Brief description of drawings]

FIG. 1 shows an example of a first image reading apparatus according to the present invention.

FIG. 2 shows a document transport mechanism of the ADF of FIG.

FIG. 3 shows an example of a second image reading apparatus according to the present invention.

FIG. 4 shows a document transport mechanism of the ADF of FIG.

FIG. 5A is a spectral sensitivity characteristic diagram showing a relationship between relative sensitivity and wavelength in color identification of each sensor,
Part (b) shows the spectral reflection data of a black and white original document.

FIG. 6 shows a circuit configuration of an image signal control unit using a 4-line image sensor having a monochrome sensor.

FIG. 7 shows a circuit configuration of an image signal control unit using a 3-line image sensor.

FIG. 8 shows setting of a reading mode in the image reading apparatus.

FIG. 9 shows a flowchart of a first image reading operation control method according to the present invention.

FIG. 10 shows a flowchart of a second image reading operation control method according to the present invention.

[Explanation of symbols]

1 Automatic document feeder (ADF) 2 reader 3 First Platen 4 light sources 5 mirror 8 Second Platen 9 Paper tray 11 Output tray 16 paper feed path 17 Transport route 18 Paper output path 19 Circulation path 20 Intermediate route 80 Evacuation route 28 Paper feed roller 31, 39 Conveyor rollers 37 Paper ejection roller 100 control device 102 line sensor 103 A / D converter 104 Shading correction unit 105 selector 106 color determination unit 107 data memory section 108 Control unit S1, S2, S5, S8 sensor M1 paper feed motor M2 transport motor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 1/46 CF term (reference) 2H076 AA02 AA07 AA57 AA58 BA15 BA24 BA35 BA36 BA47 BA56 BA59 BA63 BA68 BB10 5C062 AA02 AA05 AB17 AB32 AC15 AC58 BA04 5C072 AA01 BA03 NA07 NA08 XA01 5C079 HA11 HA13 HB01 JA01 JA23 LA03 NA11

Claims (15)

[Claims] 1. An optical reading unit arranged at a predetermined reading position under the platen for reading a document moving on a platen, and a conveying unit capable of re-feeding the same document to the reading position. And an identification unit for identifying the type of image data of the document read by the optical reading unit, and a control unit for controlling each unit, wherein the control unit is configured such that the image data is If the type is 1, the original is ejected and the image data in the first first reading mode is output, and if the image data is the second type, the original is returned to the reading position. An image reading apparatus, which controls to feed a sheet and read in a second reading mode different from the first reading mode. 2. The image reading apparatus according to claim 1, wherein, in the re-feeding, the document is conveyed in a paper discharge direction, the document is circulated, and then the document is fed again to the reading position. 3. The image reading apparatus according to claim 1, wherein in the re-feeding, the original is fed back in an upstream direction opposite to a paper discharge direction and fed again to the reading position. 4. The image reading apparatus according to claim 1, wherein a document reading speed in the first reading mode is higher than a document reading speed in the second reading mode. 5. The first reading mode is a mode for reading a monochrome image, and the second reading mode is a mode for reading a color image. The image reading device described. 6. The first reading mode is a mode for reading a binary gradation image, and the second reading mode is a mode for reading a multi-value gradation image. The image reading apparatus according to claim 1. 7. An optical reading unit arranged at a predetermined reading position under the platen for reading a document moving on a platen, and a conveying unit capable of re-feeding the same document to the reading position. And an identification unit for identifying whether the image data read by the optical reading unit is monochrome data or color data, and a control unit for controlling each unit. While the optical reading unit scans the original in the black and white reading mode, if the identifying unit identifies the image data of the original as color data, the black and white mode reading of the original is stopped and the original is read. An image reading apparatus is configured to control so that the sheet is re-fed on the platen and is read in a color reading mode. 8. The image reading method according to claim 7, wherein in the re-feeding, the document is fed back in the upstream direction opposite to the paper discharge direction and fed again to the reading position. 9. A document reading method for reading image data of a document on a platen by an optical reading unit arranged at a predetermined reading position under the platen, wherein the document is read in a first reading mode, and A step of identifying the type of image data read in the first reading mode; and when the type of the image data is identified as the first type, the original is ejected and the first reading mode is set. And outputting the image data according to the second step, and when the type of the image data is identified as the second type, the document is re-fed to the reading position and the second reading mode different from the first reading mode. And a step of reading in a reading mode of 1., and an image reading method comprising: 10. The image reading method according to claim 9, wherein in the re-feeding, the document is conveyed in a paper discharge direction, the document is circulated, and then the document is fed again to the reading position. 11. The image reading method according to claim 9, wherein in the re-feeding, an original is fed back in an upstream direction opposite to a paper discharge direction and fed again to the reading position. 12. The image reading method according to claim 9, wherein the original reading speed in the first reading mode is higher than the original reading speed in the second reading mode. 13. The method according to claim 9, wherein the first reading mode is a mode for reading a monochrome image, and the second reading mode is a mode for reading a color image. The image reading method described. 14. A document reading method for reading image data of a document on a platen by an optical reading means arranged at a predetermined reading position under the platen, a step of reading the document in a monochrome reading mode, and the monochrome reading. A step for identifying whether the image data read by the mode is black and white data, and if the type of the image data is black and white data,
Outputting the image data; stopping the scanning of the document in black and white mode when the image data is identified as color data; and re-feeding the document to the reading position. And a step of scanning the original document in a color reading mode, the image reading method comprising: 15. The sheet refeeding step is a step of feeding the document back to the reading position by feeding back the original document in an upstream direction opposite to the sheet discharge direction. The image reading method described.