JP2018067769A - Image scanner, image formation apparatus, and image-reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image scanner which enables the enhancement of color reproducibility.SOLUTION: An image scanner operable to read image information from a reading target comprises: a light-emitting part including a red light source, a green light source, a blue light source and an ultraviolet source; a light guide body for homogenizing light generated by the light-emitting part and applying the resultant light to a reading target; a photoelectric conversion part operable to output a value showing the brightness of each region of a reflection image produced by application of the light to the reading target; a cut-off filter for cutting a UV component, which is disposed on an optical path from the reading target to the photoelectric conversion part; and a control part which causes the light-emitting part to generate any of the kinds of light in a predetermined order, and which processes respective output values sequentially output from the photoelectric conversion part while associating the values with corresponding light wavelength characteristics, thereby producing image information of the reading target. The process of producing image information of the reading target includes the steps of: estimating a fluorescent light color of the reading target; and adjusting at least one output value of output values respectively output when respective colors of light from the red light source, the green light source and the blue light source are applied to the reading target, according to the estimated fluorescent light color.SELECTED DRAWING: Figure 13

Description

  The present technology relates to an image reading apparatus, an image forming apparatus, and an image reading method that generate image information from a reading target by sequentially switching and irradiating light having different wavelength characteristics.

  Image reading apparatuses that optically read image information from an arbitrary reading target are widely used. Such an image reading apparatus is often mounted as a part of an image forming apparatus such as a copying machine, a facsimile machine, or a multifunction machine.

  A configuration using a line sensor is adopted as one of typical configurations in which an image reading apparatus optically reads image information from a reading target. Specifically, the line sensor continuously acquires images from the imaging target surface to be read while relatively moving at a constant speed between the line sensor that is an imaging element and the reading target. Examples of the configuration for relative movement include a configuration for moving an original, a configuration for moving a carriage on which a line sensor is mounted, and a configuration for moving both.

  As a line sensor used in such a configuration, a so-called CCD (Charge Coupled Device) reading method, a 3-line CIS (Contact Image Sensor) reading method, a 1-line CIS reading method, etc. It has been known.

  In the CCD reading method and the 3-line CIS reading method, light having a relatively wide wavelength range (typically white light) is irradiated onto a reading target, and reflected light generated by reflection on the reading target is received by a light receiving element. Is separated into a plurality of wavelength components (generally, the three primary colors of red, green, and blue) using a color filter disposed in the vicinity of each other, and by receiving the separated wavelength components in parallel, Color image data and the like are generated by acquiring image signals for each color and processing these image signals. Such a system may be referred to as a color filter system.

  In contrast, in the one-line CIS reading method, a plurality of light sources that emit light having different wavelength characteristics (typically red light, green light, and blue light) are arranged, and the line sensor and the reading target are arranged. These light sources are repeatedly turned on in a predetermined order while being relatively moved at a constant speed, and a light receiving element having sensitivity to any wavelength of light from a plurality of light sources is used. The image signals for each color are acquired by sequentially reading the image signals in association with the light irradiation timing, and color image data and the like are generated by processing these image signals. Such a method may be referred to as a light source switching method / light source sequential method.

  The 1-line CIS scanning method is in principle inferior in color reproducibility compared with the CCD scanning method or the 3-line CIS scanning method, but requires fewer light receiving elements. Is advantageous.

  Regarding color reproducibility, for example, there is a prior art that focuses on a document included in a portion marked with a highlighter pen or the like.

  For example, Japanese Patent Laid-Open No. 10-107970 (Patent Document 1) is printed with a commercially available yellow, pink (magenta) or cyan fluorescent pen or a similar fluorescent ink. It is an object of the present invention to solve the problem that when a document image is copied, it is reproduced in a color far from the color of the document image. Specifically, the density of the image data of M, C, Y, and Bk is reduced (equivalent to increasing the density of R, G, and B) according to the fluorescence component detected when the ultraviolet light is irradiated. By performing the above, it is disclosed that the problem that the fluorescent color appears duller than it looks on the copy output is solved.

  Japanese Patent Application Laid-Open No. 2004-127235 (Patent Document 2) is an apparatus for illuminating, reading, and interpreting a mark appearing on a machine-readable zone (MRZ) of a document. Discloses a document reader in which the indicia is only visible under illumination with invisible light. Specifically, Japanese Patent Application Laid-Open No. 2004-127235 (Patent Document 2) includes an ultraviolet light source reading unit having an ultraviolet light cut filter and a visible light source reading unit having visible light having a plurality of wavelengths, and a passport. The structure which performs the detection of fluorescence marks, such as a banknote, and acquisition of a visible light image independently is disclosed.

JP-A-10-107970 JP 2004-127235 A

  The above-mentioned Japanese Patent Application Laid-Open No. 10-107970 (Patent Document 1) merely provides a solution to the problem such as “the fluorescent color looks dull than the naked eye” that can occur in the CCD reading method or the three-line CIS reading method. However, this does not solve the problem relating to color reproducibility that occurs in the one-line CIS reading method as described later.

  Japanese Patent Application Laid-Open No. 2004-127235 (Patent Document 2) is directed to a technique for detecting an invisible mark previously given to a passport, a bill, and the like, and a problem relating to color reproducibility in an image reading apparatus. It's not something to solve.

  The present technology improves color reproducibility in a configuration in which a single line sensor is used to detect reflected light generated by irradiation while sequentially switching and irradiating light having different wavelength characteristics to a reading target. One object is to provide a new configuration.

  An image reading apparatus for reading image information from a reading target according to an aspect of the present disclosure, wherein a red light source that generates light including a red wavelength component, a green light source that generates light including a green wavelength component, and a blue wavelength component A light emitting unit including a blue light source that generates light including an ultraviolet light source that generates light including an ultraviolet component, a light guide for uniformizing light emitted from the light emitting unit and irradiating the reading target, and reading A photoelectric conversion unit that outputs a value indicating the luminance of each region of the reflected image generated by light irradiation on the target, a cut filter that is disposed on the optical path from the reading target to the photoelectric conversion unit, and blocks an ultraviolet component; By generating any light from the light emitting unit in a predetermined order and processing each output value sequentially output from the photoelectric conversion unit in association with the wavelength characteristic of the corresponding light, Image information And a control unit for generating a. The process for generating the image information of the reading target is output when the fluorescent color of the reading target is estimated and the reading target is irradiated with light from the red light source, the green light source, and the blue light source according to the estimated fluorescent color. At least one of the output values is adjusted.

  Preferably, the process of generating the image information of the reading target includes an ultraviolet light source based on at least one output value among output values respectively output when the light from the red light source, the green light source, and the blue light source is irradiated to the reading target. Is adjusted according to the correction amount corresponding to the output value when the reading object is irradiated to the reading object.

  Preferably, in the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is around cyan or blue, the correction amount coefficient is small, and the fluorescent color of the reading target is around the red color. When it is estimated that there is, the coefficient of the correction amount is set large.

  Preferably, in the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is orange, the output value when the reading target is irradiated with light from the red light source is increased, and the green color is increased. The output value when the reading target is irradiated with light from the light source is decreased, and the output value when the reading target is irradiated with light from the blue light source is decreased.

  Preferably, in the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is pink, the output value when the reading target is irradiated with light from the red light source is increased. The output value when the reading object is irradiated with light from the green light source is decreased.

  Preferably, in the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is yellow, the output value when the reading target is irradiated with light from the red light source is increased, and the green color is increased. The output value when the reading object is irradiated with light from the light source is increased, and the output value when the light from the blue light source is irradiated onto the reading object is decreased.

  Preferably, in the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is green, the output value when the reading target is irradiated with light from the green light source is increased, and the blue color The output value when the light from the light source is irradiated to the reading object is decreased.

  Preferably, in the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is blue, the output value when the light from the blue light source is irradiated to the reading target is increased.

  Preferably, in the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is cyan, the output value when the light from the green light source is irradiated to the reading target is increased. The output value is increased when the reading target is irradiated with light from the blue light source.

  An image forming apparatus according to an aspect of the present disclosure includes an image reading apparatus that reads image information from a reading target, and an image forming unit that forms an image based on the image information read by the image reading apparatus. The image reading apparatus includes a red light source that generates light including a red wavelength component, a green light source that generates light including a green wavelength component, a blue light source that generates light including a blue wavelength component, and light including an ultraviolet component. A light emitting unit including an ultraviolet light source that is generated, a light guide for uniformizing the light generated from the light emitting unit and irradiating the reading target, and the luminance of each region of the reflected image generated by the light irradiation to the reading target A photoelectric conversion unit that outputs the indicated value, a cut filter that is arranged on the optical path from the reading target to the photoelectric conversion unit, and blocks ultraviolet components, and generates any light from the light emitting unit in a predetermined order. And a control unit that generates image information to be read by processing each output value sequentially output from the photoelectric conversion unit in association with the wavelength characteristic of the corresponding light. The process for generating the image information of the reading target is output when the fluorescent color of the reading target is estimated and the reading target is irradiated with light from the red light source, the green light source, and the blue light source according to the estimated fluorescent color. At least one of the output values is adjusted.

  An image reading method for reading image information from a reading object according to an aspect of the present disclosure, wherein a red light source that generates light including a red wavelength component, a green light source that generates light including a green wavelength component, and a blue wavelength component A step of generating any light in a predetermined order from a light emitting unit including a blue light source that generates light and an ultraviolet light source that generates light including an ultraviolet component, and the light generated from the light emitting unit A cut filter for blocking the ultraviolet component is arranged on the optical path from the reading object to the photoelectric conversion unit after being made uniform by the light guide, and output sequentially from the photoelectric conversion unit Storing the output value indicating the brightness of each region of the reflected image generated by light irradiation to the reading object in association with the wavelength characteristic of the corresponding light, and generating the image information of the reading object from the stored output value. And a step of. The step of generating the image information of the reading target includes the steps of estimating the fluorescent color of the reading target and outputting when the light from the red light source, the green light source, and the blue light source is irradiated to the reading target according to the estimated fluorescent color, respectively. Adjusting at least one of the output values to be output.

  According to the present technology, color reproducibility is achieved in a configuration in which a single line sensor is used to detect reflected light generated by irradiation while sequentially switching and irradiating light having different wavelength characteristics to a reading target. It can be improved.

1 is a schematic diagram showing an external configuration example of an image forming apparatus including an image reading apparatus according to the present embodiment. It is a schematic diagram which shows the cross-sectional structural example of the image reading apparatus 4 according to this Embodiment. It is a schematic diagram which shows the structural example of the 1 line CIS reading system according to related technology. It is a schematic diagram for demonstrating the wavelength characteristic of the reflected light which arises from the drawing part by fluorescent dye. It is a figure for demonstrating the process in the case of reading the reading object containing the drawing part by a fluorescent dye by 1 line CIS reading system. It is a schematic diagram which shows an example of the reproduction result of the image information each read by the CCD reading system and the 1 line CIS reading system from the reading object which has the drawing part containing fluorescent dye. It is a schematic diagram which shows the structural example of the reading part 22 of the image reading apparatus 4 according to this Embodiment. It is a figure which shows an example of the wavelength characteristic (spectrum) of each light source and ultraviolet region cut filter which comprises the light emission part 220 shown in FIG. It is a schematic diagram for demonstrating the preferable lighting sequence of the light source in the fluorescence correction process in the image reading apparatus 4 according to the present embodiment. It is a figure which shows an example of the reading result of CCD reading system and 1 line CIS reading system. It is a figure which shows another example of the reading result of a CCD reading system and a 1 line CIS reading system. It is a schematic diagram which shows the hardware structural example which concerns on the image reading in the image reading apparatus 4 according to this Embodiment. It is a flowchart which shows the process sequence of the fluorescence correction process in the image reading apparatus 4 according to this Embodiment. It is a figure explaining an example of an interpolation table.

  Embodiments of the present invention will be described in detail with reference to the drawings. In addition, about the same or equivalent part in a figure, the same code | symbol is attached | subjected and the description is not repeated.

<A. Device configuration>
Next, the apparatus configuration of the image reading apparatus and the image forming apparatus including the image reading apparatus according to the present embodiment will be described. Hereinafter, as a typical example, an image forming apparatus 1 that is mounted as a multi-functional peripheral (MFP) including an image reading apparatus will be described. The present invention is not particularly limited to this, and may be implemented as a copier or facsimile including an image reading apparatus, or the image reading apparatus may be implemented as a single apparatus.

(A1: Image forming apparatus)
FIG. 1 is a schematic diagram showing an external configuration example of an image forming apparatus including an image reading apparatus according to the present embodiment. Referring to FIG. 1, image forming apparatus 1 according to the present embodiment has a plurality of functions such as a copy function, a scanner function, a printer function, and a fax function, such as a LAN (Local Area Network) and a telephone line. Data can be sent and received over the network. That is, the image forming apparatus 1 can output image information (image data) read from a reading target to another computer via a network as a scanner function or a copy function, and can function as a printer function or a fax function via a network. Image information (image data) is acquired from another computer, and printing based on the image data or FAX transmission can be performed.

  When the image reading apparatus is mounted on the image forming apparatus, any method may be adopted for the image forming unit (print engine) of the image forming apparatus. For example, an electrophotographic system (monochrome system or color system), an inkjet system, a thermal system, a thermal transfer system, and the like can be given. FIG. 1 shows an image forming apparatus 1 adopting an electrophotographic system as a typical example.

  The image forming apparatus 1 includes an image forming unit 5, a paper feeding unit 6 disposed below the image forming unit 5, and an image reading device 4 disposed above the image forming unit 5.

  The image reading device 4 reads image information from a reading target and outputs image data and the like, and mainly includes a reading main body unit 2 and an automatic document conveying unit 3. The user can place one document directly on the reading main unit 2 to read the image information, or one or more documents can be placed on the automatic document feeder 3 to continuously send the image information. It can also be read. In this continuous reading operation, the reading main body unit 2 and the automatic document conveying unit 3 operate in synchronization to convey the originals arranged in the automatic document conveying unit 3 one by one toward the reading main body unit 2. The reading main unit 2 reads image information when the document passes a predetermined position, and generates image data.

  The paper supply unit 6 stores paper as a recording medium and supplies the stored recording media one by one to the image forming unit 5 in correspondence with the image forming operation in the image forming unit 5.

  The image forming unit 5 puts an image on a recording medium supplied from the paper feeding unit 6 based on image data read by the image reading device 4, image data acquired via a network, directly input image data, and the like. Form. As described above, the image forming unit 5 prints arbitrary image data on the recording medium. As one typical example, the image forming unit 5 forms an image based on image information read by the image reading device 4. The recording medium on which the image is formed by the image forming unit 5 is output to the paper discharge unit 7 between the image forming unit 5 and the reading main body unit 2.

  An operation panel 8 having a plurality of keys or buttons is provided on the front side (side operated by the user) of the image forming apparatus 1. The operation panel 8 receives an operation instruction from the user and outputs the received operation instruction to the image forming unit 5 or the like.

(A2: Image reading apparatus)
Next, the device configuration of the image reading device 4 shown in FIG. 1 will be described in more detail.

FIG. 2 is a schematic diagram showing a cross-sectional configuration example of the image reading device 4 according to the present embodiment.
In the configuration example of the image reading device 4 shown in FIG. 2, image information can be read from both sides of the document. Specifically, the automatic document feeder 3 has a paper feed tray 31 on which one or a plurality of documents 70 are arranged. The originals 70 arranged on the paper feed tray 31 are sent out one by one from the top layer to the original conveyance path 30 by the pickup roller 32 and the paper feed roller pair 33. In the document transport path 30, the document 70 is transported to the registration roller pair 35 by the intermediate roller pair 34. The registration roller pair 35 functions as a skew feeding correction roller, corrects the conveyed document 70 to the original posture, and sends the document 70 toward the first conveyance roller pair 36 at a predetermined timing. The document 70 is sent out onto the slit glass 21 which is the conveyance reading surface of the reading main body 2 by the first conveyance roller pair 36 and passes over the slit glass 21 by the reading roller 42.

  When the document 70 passes over the slit glass 21, the first reading unit 22 positioned below the slit glass 21 reads image information on the downward surface (front surface) of the document 70.

  A second conveyance roller pair 37, a second reading unit 38, a third conveyance roller pair 39, and a paper discharge roller 40 are arranged on the document conveyance path 30 downstream of the slit glass 21. The document 70 that has passed over the slit glass 21 is sent out to just below the second reading unit 38 by the second transport roller pair 37. When the document 70 passes directly below the second reading unit 38, the image information of the upward surface (back surface) of the document 70 is read.

  The document 70 that has passed directly under the second reading unit 38 is discharged onto the paper discharge tray 41 by the third conveyance roller pair 39 and the paper discharge roller 40.

  A slit glass 21 and a platen glass 23 are provided on the upper surface of the reading main body 2. The first reading unit 22 is disposed inside the reading main body unit 2. The first reading unit 22 is used to read image information on the surface of the document 70 that passes over the slit glass 21 and / or image information of the document 70 disposed on the platen glass 23. When reading the image information of the document 70 passing over the slit glass 21, the scanning unit 24 and the traveling unit 25 are placed in a fixed state. On the other hand, when reading the image information of the document 70 placed on the platen glass 23, the scanning unit 24 and the traveling unit 25 move in the sub-scanning direction Y, so that the reading range of the first reading unit 22 is sequentially changed. To do.

  The scanning unit 24 and the traveling unit 25 are supported by a pair of support rails 46 disposed in the reading main body unit 2 and are slid by the power of an actuator (not shown).

  The second reading unit 38 is fixedly disposed in the automatic document feeder 3. The second reading unit 38 reads image information on the back side of the document 70 conveyed by the reading roller 43. The reading roller 43 has a function as a white reference body for shading correction in addition to a function of conveying the document 70.

  The first reading unit 22 and the second reading unit 38 include a light source for irradiating light toward the reading target surface of the document and a line sensor for receiving reflected light generated by the reading target. The line sensor is composed of a plurality of photoelectric conversion elements arranged along the main scanning direction, and outputs an output value corresponding to the luminance (light intensity) of incident reflected light. That is, the line sensor converts an optical reflection image generated in the reading target into an electrical image signal and outputs the electrical image signal.

  In image reading apparatus 4 according to the present embodiment, CIS is used as at least one line sensor of first reading unit 22 and second reading unit 38. In particular, the first reading unit 22 and / or the second reading unit 38 employs a one-line CIS reading method.

  Note that it is not necessary to adopt the one-line CIS reading method for both the first reading unit 22 and the second reading unit 38, and the one-line CIS reading method may be adopted for only one of the first reading unit 22 and the second reading unit 38. Only one of the first reading unit 22 and the second reading unit 38 may be employed in the device 4.

<B. Newly discovered issues>
Next, a related configuration example of the one-line CIS reading method will be described, and a newly discovered problem in the related configuration example will be described. In the following description, the first reading unit 22 and the second reading unit 38 shown in FIG. 2 may be collectively referred to as “reading unit 22”.

(B1: Related configuration example)
FIG. 3 is a schematic diagram showing a configuration example of a one-line CIS reading method according to the related art.

  The reading unit 22 # of the 1-line CIS reading system sequentially switches and irradiates light having different wavelength characteristics to the reading target, and sequentially reflects reflected images generated from the reading target with a common light receiving element (photoelectric conversion element). Image information is generated by combining the detected results.

  More specifically, the reading unit 22 # according to the related technique shown in FIG. 3 includes a light emitting unit 220 # that generates light for irradiating the target surface to be read, and light generated from the light emitting unit 220 #. And a line sensor 226, and an imaging lens 224 that forms a reflected image from the reading object on a detection surface on the line sensor 226.

  The light emitting unit 220 # is a light emitting unit for generating red, green, and blue colors of light to be applied to the reading target. The light emitting unit 220 # includes a red light source (hereinafter also referred to as “R light source”) 220R that generates light including a red wavelength component and a green light source (hereinafter referred to as “G light source”) that generates light including a green wavelength component. 220G and a blue light source (hereinafter also referred to as “B light source”) 220B that generates light including a blue wavelength component.

  The light guide 222 is disposed integrally with or close to the light emitting unit 220 #, spatially smoothes (uniformizes) the light generated from the light emitting unit 220 #, and emits light from the light emitting unit 220 #. Direct light in the direction of the reading object.

  The line sensor 226 uses a CIS in which a plurality of photoelectric conversion elements are arranged along the main scanning direction. The line sensor 226 is a kind of sensor group in which monochrome sensors are arranged in a line, and each photoelectric conversion element has a size corresponding to the luminance (brightness / light intensity) of an image incident on each photoelectric conversion element. The signal is output.

  The imaging lens 224 is an imaging optical system for shortening the focal length of the line sensor 226. For example, an SLA (Selfoc Lens Array) in which a plurality of gradient index lenses are arranged along the main scanning direction is used. Can be used. The SLA is an imaging optical system that can form one continuous image as a whole on the line sensor 226.

  In the reading unit 22 # shown in FIG. 3, a single line sensor 226 (monochrome sensor array) is used to sequentially switch the light source irradiated from the light emitting unit 220 #, thereby including a plurality of images included in the reflected image from the reading target. Are separated in time. That is, line data for each color of R, G, and B is sequentially acquired by sequentially switching the R light source 220R, the G light source 220G, and the B light source 220B included in the light emitting unit 220 #. Since there is no mechanism for wavelength separation when acquiring this line data, it is assumed that it received light of the same wavelength as the light from the light source that was emitting when each line data was acquired. Are separated in time.

  The electric signal output from the line sensor 226 is given to an image processing unit (not shown), and is digitized image data through analog signal processing, A / D (Analog to Digital) conversion, shading correction, image compression processing, and the like. Is output as In the process for outputting the image data, the line data for each color is multiplied by the wavelength characteristic of the corresponding light source, so that the spectrum of the reflected image and the color image information of the reflected image can be reproduced.

(B2: newly discovered issues)
Next, a new problem relating to color reproducibility discovered by the inventors of the present application, which may occur when image information is read using a reading unit of the one-line CIS reading method as shown in FIG. 3, will be described.

  When reading image information of a document using a reading unit of a one-line CIS reading system as shown in FIG. 3, if there is a region drawn with a fluorescent dye in the document, the read image information The inventor of the present application has newly discovered that there is a problem inherent to the one-line CIS reading method that the color becomes lighter than the original color and disappears. For example, a document marked with a commercially available fluorescent pen or the like includes an area for drawing with a fluorescent dye, and the color of the target area is light in image data read from such a document. Or it may disappear and disappear.

  Such a phenomenon is caused by a combination of the property of fluorescence and the principle of the one-line CIS reading method. Hereinafter, the reason why such a phenomenon occurs will be described.

  FIG. 4 is a schematic diagram for explaining wavelength characteristics of reflected light generated from a drawing portion by a fluorescent dye.

  FIG. 5 is a diagram for explaining processing when a reading target including a drawing portion by a fluorescent dye is read by a one-line CIS reading method.

  In general, a fluorescent dye absorbs a component having a specific wavelength or a specific wavelength range unique to each dye, and generates light (fluorescence) having a wavelength longer than the absorbed wavelength. For example, a fluorescent dye that emits red or yellow fluorescence having a long wavelength in visible light absorbs a component such as blue having a shorter wavelength of visible light and emits red or yellow light.

  FIG. 4 shows an example in which blue light is applied to the document 70 including the drawing portion 72 traced with the highlighter pen. In this case, the reflected light generated from the drawing portion 72 mainly contains a yellow wavelength component.

  FIG. 5 shows a process of reading image information using the reading unit 22 # of the one-line CIS reading method with the original 70 shown in FIG. 4 as a reading target. As described with reference to FIG. 4, when the B light source 220 </ b> B is turned on, reflected light mainly including a yellow wavelength component is generated from the document 70 to be read. Since the color sensor is not attached to the line sensor 226 of the reading unit 22 #, when reflected light mainly including a yellow wavelength component is incident, the B light source 220B is irradiated with an electrical signal corresponding to the luminance of the incident reflected light. Is output as the detected value (B signal). However, since the reflected light incident on the line sensor 226 is approximately yellow light, the output B signal has an erroneous detection result.

  That is, since the reading unit 22 # of the one-line CIS reading method does not have a mechanism (for example, a color filter) that separates light in which reflected light and fluorescence are mixed according to color, fluorescence included in received light. The components cannot be separated. Since it is the output from the line sensor 226 in which the B light source 220B is lit, it is erroneously determined as reflected light of blue light.

  As a result, for the yellow drawing that should be originally obtained, the output when irradiating blue light that should be absorbed by the fluorescent dye is excessively expressed by the fluorescent dye, resulting in the total output of the image signal for each color. As the value, the luminance may be larger than the original value, that is, reproduced as a light color close to white, or the calculated luminance may be too large to disappear.

  FIG. 6 is a schematic diagram showing an example of reproduction results of image information read from a reading target having a drawing portion containing a fluorescent dye by a CCD reading method and a one-line CIS reading method, respectively.

  FIG. 6A shows an example of a result obtained by reading image information from a document 70 having a drawing portion 72 containing a fluorescent dye as a reading target by the CCD reading method.

  In the reproduced image thus reproduced, the drawing portion 82 corresponding to the drawing portion 72 containing the fluorescent dye is reproduced in substantially the same state.

  FIG. 6B shows an example of the result of reading image information from a document 70 having a drawing portion 72 containing a fluorescent dye, using the reading unit 22 # of the one-line CIS reading method as shown in FIG. .

  In the reproduced image thus reproduced, the drawing portion 92 corresponding to the drawing portion 72 containing the fluorescent dye becomes thin as a whole.

  The image reading apparatus including the reading unit of the one-line CIS reading method according to the present embodiment improves the reading accuracy of the drawing portion including the fluorescent dye and takes color reproducibility in consideration of the new problem as described above. The purpose is to increase.

  When the unit costs of the line sensors of the CCD reading method and the one-line CIS reading method are compared, the unit cost decreases in the order of the CCD reading method and the one-line CIS reading method. In other words, it is important to solve the problems inherent in the one-line CIS reading method in order to reduce the cost.

<C. Configuration of Image Reading Device>
Next, an example of an image reading apparatus capable of solving the new problem relating to color reproducibility discovered by the present inventors as described above will be described.

  In the image reading device 4 according to the present embodiment, in addition to the light source (R light source, G light source, B light source) for acquiring the image signal for each original color, for the new problem as described above, Mainly, another light source for generating a fluorescent component from the fluorescent dye is disposed, and a process for detecting and correcting the fluorescent component generated by light irradiation from the other light source is employed.

  More specifically, in a one-line CIS reading type image reading apparatus, in addition to a normal light source (R light source, G light source, B light source), a light source that generates light in the ultraviolet region, and reflection from the reading target. A cut filter that blocks the ultraviolet component of the light is additionally arranged. Then, by correcting the image signal for each color (reading intensity for each color) using the fluorescent component from the reading target detected when the reading target is irradiated with light from the ultraviolet light source, the color for the fluorescent color Improve reproducibility and readability.

  FIG. 7 is a schematic diagram showing a configuration example of the reading unit 22 of the image reading device 4 according to the present embodiment.

  Referring to FIG. 7, reading unit 22 of image reading apparatus 4 according to the present embodiment employs a one-line CIS reading type line sensor, and sequentially applies light having different wavelength characteristics to the reading target. While switching and irradiating, image information is generated by combining the results of sequentially detecting reflected images generated from the reading target with a common light receiving element (photoelectric conversion element).

  More specifically, the reading unit 22 generates light for irradiating the target surface to be read, and the light generated from the light emitting unit 220 is made uniform to irradiate the reading target. The light guide 222, the line sensor 226, an image forming lens 224 for forming an image reflected from the reading object on the detection surface on the line sensor 226, and a cut filter 228 for blocking the ultraviolet component.

  The light emitting unit 220 is a light emitting unit for generating light of each color of red, green, and blue to be irradiated to the reading target. In addition to the red light source (R light source) 220R, the green light source (G light source) 220G, and the blue light source (B light source) 220B, the light emitting unit 220 generates an ultraviolet light source (hereinafter referred to as “UV”) that includes light including an ultraviolet component. Also referred to as “light source.”) 220UV.

  The light guide 222 is disposed integrally with or adjacent to the light emitting unit 220, spatially smoothes (homogenizes) the light generated from the light emitting unit 220, and reads the light from the light emitting unit 220. Orient in the direction of the target. The light guide 222 is a member for guiding the light generated by the light emitting unit 220 to the reading target. Typically, the light guide 222 is made of an optical material such as a resin such as acrylic or glass.

  The line sensor 226 uses a CIS in which a plurality of photoelectric conversion elements are arranged along the main scanning direction. The line sensor 226 is a kind of sensor group in which monochrome sensors are arranged in a line, and each photoelectric conversion element has a size corresponding to the luminance (brightness / light intensity) of an image incident on each photoelectric conversion element. The electrical signal is output. The line sensor 226 is a photoelectric conversion element that converts an optical image formed by the imaging lens 224 into a potential signal. Each line sensor 226 has a reflection image generated by light irradiation on a reading target (on the light receiving surface of each photoelectric conversion element). This corresponds to a photoelectric conversion unit that outputs a value indicating luminance.

  The technical idea according to the present invention is not limited to the name CIS, but may be a configuration in which a plurality of wavelength components included in a reflected image from a reading target are temporally separated using a common photoelectric conversion unit. For example, it can be applied to any configuration.

  For example, the line sensor 226 may be configured using a CCD without a color filter. Further, the array of light receiving elements (photoelectric conversion elements) of the line sensor 226 is not limited to one column, and may be a plurality of columns.

  An electric signal output from the line sensor 226 is given to an image processing unit described later, and analog signal processing, A / D (Analog to Digital) conversion, correction processing according to the present embodiment (fluorescence correction processing described later), It is output as digitized image data through shading correction, image compression processing, and the like. In the process for outputting the image data, the line data for each color is multiplied by the wavelength characteristic of the corresponding light source, so that the spectrum of the reflected image and the color image information of the reflected image can be reproduced.

  The imaging lens 224 is an imaging optical system for shortening the focal length of the line sensor 226. For example, an SLA (Selfoc Lens Array) in which a plurality of gradient index lenses are arranged along the main scanning direction is used. Can be used. The SLA is an imaging optical system that can form one continuous image as a whole on the line sensor 226.

  The cut filter 228 is a band pass filter or a band cut filter that blocks an ultraviolet component, and is disposed on the optical path from the reading target to the line sensor 226 that is a photoelectric conversion unit. Accordingly, the ultraviolet component between the reading target and the photoelectric conversion element is blocked on the optical path of the light emitting unit 220 that generates the ultraviolet component light. In the configuration example illustrated in FIG. 7, an example in which the reading target is disposed between the imaging lens 224 and the imaging lens 224 is illustrated. However, the configuration may be disposed between the imaging lens 224 and the line sensor 226.

  The image reading device 4 reads image data corresponding to the wavelength component of the light emitted from the light emitting unit 220 based on the potential signal from the photoelectric conversion element when each light source of the light emitting unit 220 is caused to emit light sequentially. .

  FIG. 8 is a diagram illustrating an example of wavelength characteristics (spectrums) of the light sources and the ultraviolet cut filter that constitute the light emitting unit 220 illustrated in FIG. 7.

  Referring to FIG. 8, R light source 220R, G light source 220G, and B light source 220B generate light having wavelength characteristics such that the respective peak emission wavelengths correspond to red, green, and blue.

  The UV light source 220UV is a light emitting means for generating ultraviolet component light, and generates light having a wavelength characteristic whose peak emission wavelength is in the ultraviolet region. The light generated by the UV light source 220UV only needs to include a component in the ultraviolet region, and may include a component in the visible region in addition to that. That is, the spectrum of light generated by the UV light source 220UV may be from the ultraviolet range to the visible range. However, it is preferable that the light generated by the UV light source 220UV and the light generated by the R light source 220R do not overlap in the wavelength range. That is, it is preferable that the wavelength of the light from the UV light source 220UV is set so as not to overlap with the wavelength of the light from the R light source 220R. Even if there is an overlapping wavelength range between the light from the UV light source 220UV and the light from the R light source 220R, there is no substantial problem if the intensity difference is sufficiently large.

  FIG. 8 also shows the cutoff characteristics of the cut filter 228. The cut filter 228 prevents light (ultraviolet light) from the UV light source 220 UV from directly entering the line sensor 226. The light from the UV light source 220UV is used to generate a fluorescent component from the reading target. When the generated fluorescent component and the light from the UV light source 220UV are mixed and enter the line sensor 226, fluorescence is emitted. It becomes impossible to estimate the intensity of the component. Therefore, as the cut filter 228, a filter having a blocking characteristic that can block substantially all of the light from the UV light source 220UV is employed.

  However, the cut filter 228 does not need to completely block the light from the UV light source 220UV, and it is desirable that the intensity of transmitted light (ultraviolet light) can be equal to or lower than the detection sensitivity of the line sensor 226.

  Next, a preferable lighting order of the light sources in the fluorescence correction processing in image reading apparatus 4 according to the present embodiment will be described.

  FIG. 9 is a schematic diagram for illustrating a preferable lighting order of light sources in the fluorescence correction processing in image reading apparatus 4 according to the present embodiment.

  FIG. 9A shows a reading range when each light source is turned on during an image reading operation in the image reading device 4. In general, in the one-line CIS reading method, when each line (each dot) is read, the relative movement between the original or the line sensor is continuously performed without stopping. In association with this continuous relative movement, a plurality of light sources are sequentially turned on to acquire image signals for each color, and therefore, as shown in FIG. A predetermined amount of displacement occurs in the position (1/3 dot when using 3 light sources, 1/4 dot when using 4 light sources).

  Strictly speaking, the output values S_R, S_G, S_B, and S_UV from the line sensor 226 mean values of reading ranges different from each other to be read. Regarding the output values S_R, S_G, and S_B used for the image data, these reading position errors can be corrected in consideration of the continuity in the sub-scanning direction, but the output value S_UV used only for the fluorescence correction processing is It is difficult to make corrections that reflect the continuity in the sub-scanning direction.

  Therefore, the light emission sequence of the B light source 220B, which has a short wavelength and is easily influenced by the fluorescent component, and the UV light source 220UV for measuring the size of the fluorescent component are made adjacent to each other, which is inherent to the one-line CIS reading method. The influence on the image quality due to the reading position error can be reduced. That is, among the four light sources consisting of red, green, blue, and ultraviolet light, the ultraviolet light source and the blue light source may be caused to emit light in the sequential order.

  Thus, as the lighting order of the light sources, it is determined that the B light source 220B and the UV light source 220UV emit light at least continuously, so that the accuracy of fluorescence correction can be increased.

<D. Overview of scan results and correction process>
Next, correction processing in the image reading apparatus according to the present embodiment will be described while comparing the CCD reading system according to the related art and the 1-line CIS reading system.

(D1: Reading result)
First, the reading results of the CCD reading method and the one-line CIS reading method described in FIG. 6 are shown below.

  FIG. 10 is a diagram illustrating an example of reading results of the CCD reading method and the one-line CIS reading method.

  In the reading result shown in FIG. 10A, the output value from the photoelectric conversion element is shown for the mark portion with yellow fluorescent ink in the CCD reading method.

  Also, in the reading result shown in FIG. 10B, the output value from the photoelectric conversion element is shown for the mark portion with yellow fluorescent ink in the one-line CIS reading method.

  The respective output values S_R, S_G, and S_B output from the photoelectric conversion elements corresponding to a specific pixel when the R light source 220R, the G light source 220G, and the B light source 220B are sequentially turned on once are shown. The output values are standardized in the range of 0 to 255 of 8 bits. Note that when the output values S_R, S_G, and S_B are all 0, it corresponds to black, and when the output values S_R, S_G, and S_B are all 255, it corresponds to white.

  In the CCD reading method, the color appearance visually matches the read color.

  On the other hand, regarding the mark portion with yellow fluorescent ink in the one-line CIS reading method, the color appearance visually does not match the read color.

  Generally, a yellow fluorescent ink contains a fluorescent dye that emits yellow fluorescence and a yellow dye that mainly absorbs a blue wavelength component, and white light (that is, red light, green light, blue light). When it is irradiated with light (including all), it will look bright yellow. In order to reproduce this visual appearance, ideally, the output values S_R and S_G should be large and the output value S_B should be small as shown in FIG.

  However, in FIG. 10B, ideally, the value added to the output values S_R and S_G is added to the value of the output value S_B. As a result, the difference between the output values S_R and S_G and the output value S_B is reduced, so that a drawing portion that should originally look bright yellow is read as light yellow that is close to white. The image reading apparatus according to the present embodiment solves such a problem of color reproducibility by performing correction processing as described later.

  FIG. 11 is a diagram illustrating another example of the reading result of the CCD reading method and the one-line CIS reading method.

  In the reading result shown in FIG. 11A, the output value from the photoelectric conversion element is shown for the mark portion of each color fluorescent ink in the CCD reading method.

  In the reading result shown in FIG. 11B, the output value from the photoelectric conversion element is shown for the mark portion of each color fluorescent ink in the one-line CIS reading method.

  Here, the output value from the photoelectric conversion element is shown for the mark portion with the orange, pink, yellow, green, blue, and blue-green fluorescent inks.

  It is necessary to adjust the output value from the photoelectric conversion element according to the relationship between the wavelength of the light generated by each light source and the characteristics of the fluorescent dye of each color.

  The image reading device 4 according to the present embodiment is a photoelectric conversion obtained when the image reading device 4 sequentially turns on each of four light sources including the R light source 220R, the G light source 220G, the B light source 220B, and the UV light source 220UV. Based on the output value from the element, image information in one row in the main scanning direction is read.

  Specifically, the color of the fluorescent ink in the mark portion is estimated based on each output value from the photoelectric conversion element. Then, at least one of the output values S_R, S_G, and S_B is adjusted based on the estimated color of the fluorescent ink.

  When the color of the fluorescent ink in the mark portion is estimated based on each output value from the photoelectric conversion element, for example, when it is estimated that the color of the fluorescent ink has an orange feature, as shown in FIG. In addition, the output value S_B is significantly decreased, the output value S_G is slightly decreased, and the output value S_R is slightly increased.

  For example, when it is estimated that the color of the fluorescent ink has a pink color characteristic, as shown in FIG. 11B, the value of the output value S_G is significantly lowered and the output value S_R is adjusted slightly higher.

  For example, when it is estimated that the color of the fluorescent ink has a yellow characteristic, as shown in FIG. 11B, the value of the output value S_B is significantly reduced, and the output value S_G and the output value S_R are slightly increased. Adjust to.

  For example, when it is estimated that the color of the fluorescent ink has a green characteristic, as shown in FIG. 11B, the value of the output value S_B is lowered and adjusted to increase the output value S_G.

  For example, when it is estimated that the color of the fluorescent ink has a blue characteristic, the output value S_B is adjusted to be significantly increased as shown in FIG.

  For example, when it is estimated that the color of the fluorescent ink has a blue-green feature, the output value S_B and the output value S_G are adjusted to slightly increase as shown in FIG.

  Hereinafter, such correction processing is also referred to as “fluorescence correction processing”, and the contents of the fluorescence correction processing will be described.

  Note that the name “fluorescence correction processing” is for convenience, and correction processing when a substance having the same characteristics as the fluorescent substance is present in the reading target can also be included in the technical scope of the present invention.

<E. Control Configuration and Control Method>
Next, a control configuration and a control method for realizing image reading according to the present embodiment will be described.

(E1: Hardware configuration example)
FIG. 12 is a schematic diagram showing a hardware configuration example related to image reading in the image reading device 4 according to the present embodiment.

  FIG. 12 shows a block diagram of the reading main body 2 and its peripheral circuits. As an example, FIG. 12 shows a configuration example in which the controller board 60 and the image processing unit 50 arranged in the reading main body 2 (see FIGS. 1 and 2) cooperate to realize a control function. .

  In the configuration shown in FIG. 12, the control functions (the controller board 60 and the image processing unit 50) generate any light from the light emitting unit 220 in a predetermined order and from the line sensor 226 (photoelectric conversion unit). Each output value sequentially output is processed in association with the wavelength characteristic of the corresponding light, thereby generating image information to be read.

  The controller board 60 controls the irradiation timing of the light from the light emitting unit 220 and acquires an electrical signal output from the line sensor 226 (photoelectric conversion element) according to the irradiation timing of each light. More specifically, the controller board 60 includes a timing control unit 62, a light emission control unit 64, and a signal acquisition unit 66.

  The timing control unit 62 determines the timing of light generated from the light emitting unit 220 based on the conveyance speed of the document to be read, and supplies the timing to the light emission control unit 64 and also receives the electrical signal input from the signal acquisition unit 66. Depending on the type of light source emitting at that time, the output value is output as one of S_R, S_G, S_B, and S_UV.

  The light emission control unit 64 includes an R light source 220R, a G light source 220G, a B light source 220B, and a UV light source 220UV (typically, an LED (Light Emitting Diode)) that constitutes the light emission unit 220 in accordance with a command from the timing control unit 62. One of these is selectively driven. The signal acquisition unit 66 activates the photoelectric conversion elements constituting the line sensor 226 in accordance with a command from the timing control unit 62, thereby acquiring an electrical signal indicating a reflected image incident from the reading target, and the acquired electrical The signal is output to the timing control unit 62.

  The image processing unit 50 receives the output values S_R, S_G, S_B, and S_UV from the controller board 60 and outputs image data that is a read result. More specifically, the image processing unit 50 includes a fluorescence correction processing unit 52, an edge detection unit 54, and a color correction unit 56.

  The fluorescence correction processing unit 52 performs the above-described fluorescence correction processing on the output values S_R, S_G, S_B, and S_UV from the controller board 60, and correction values I_R, I_G, and I_B indicating the corrected image information. Is generated.

  The edge detection unit 54 and the color correction unit 56 reproduce image information based on the correction values I_R, I_G, and I_B from the fluorescence correction processing unit 52 and execute necessary input image processing to obtain final image data. Output as. Based on the output image data, an image forming process or the like is executed.

  Note that some or all of the functions of the fluorescence correction processing unit 52 and the input image processing (such as the edge detection unit 54 and the color correction unit 56) included in the image processing unit 50 may be implemented in the reading main body unit 2. Alternatively, the functions shown in FIG. 12 may be realized by using a single system board or the like, and a part of the functions shown in FIG. 12 is realized by a hard wired circuit, and the remaining functions are executed by a processor. You may make it implement | achieve by doing.

  The present invention does not limit the mounting form of the image reading apparatus, and those skilled in the art will appropriately mount it using any technique actually obtained.

(E2: Processing procedure)
Next, an image reading processing procedure in image reading apparatus 4 according to the present embodiment will be described.

  FIG. 13 is a flowchart showing a processing procedure of fluorescence correction processing in image reading apparatus 4 according to the present embodiment.

  Each step shown in FIG. 13 may be realized in cooperation with the image processing unit 50 and the controller board 60, or may be realized by a program of the control device executing the program.

  First, when the image reading timing for the reading target arrives, the image reading device 4 selects one light source in accordance with a predetermined order from among a plurality of light sources constituting the light emitting unit 220, and outputs light from the selected light source. Irradiate the reading target. In other words, the image reading device 4 generates any light in a predetermined order from the light emitting unit 220 including the R light source 220R, the G light source 220G, the B light source 220B, and the UV light source 220UV.

  At the same time, an output value is acquired from the line sensor 226 and stored in association with the selected light source and the current reading position. That is, the image reading device 4 outputs the output value indicating the luminance of each region of the reflected image that is sequentially output from the line sensor 226 (photoelectric conversion unit) and is generated by light irradiation to the reading target, that is, the wavelength characteristic of the corresponding light (ie , Color) and stored.

  Next, the image reading device 4 generates image information to be read from the stored output value. When the image information to be read is generated, fluorescence correction processing is performed. The fluorescence correction process is executed by the fluorescence correction processing unit 52.

  In the fluorescence correction process, the fluorescence correction processing unit 52 determines whether the UV data is equal to or greater than a predetermined value (step S2).

  Next, in step S2, if the fluorescence correction processing unit 52 determines that the UV data is not equal to or greater than the predetermined value (NO in step S2), the process ends (END).

  On the other hand, when it is determined in step S2 that the UV data is greater than or equal to the predetermined value (YES in step S2), the fluorescence correction processing unit 52 executes the fluorescence correction process in and after step S4.

  In step S4, the fluorescence correction processing unit 52 estimates the fluorescence color (step S4). Specifically, the fluorescence correction processing unit 52 receives the output values S_R, S_G, S_B, and S_UV from the controller board 60 and estimates which fluorescent color is approximated. For example, a correlation value with the reading result of each fluorescent color in the one-line CIS reading method described with reference to FIG. 11 is calculated, and is estimated as a fluorescent color for the reading result with a high correlation value.

  Next, the fluorescence correction processing unit 52 calculates the adjustment amount α based on the UV data (step S6). In this example, correction is performed using the output value S_UV obtained when the UV light source 220UV is turned on. Specifically, the adjustment amount α is calculated from the output value S_UV−the fixed value REFuv. The fixed value REFuv is a fixed value and is used to offset the value of the component that could not be removed by the cut filter 228.

  Next, the fluorescence correction processing unit 52 calculates an interpolation coefficient β based on the interpolation table (step S8).

FIG. 14 is a diagram illustrating an example of the interpolation table.
As illustrated in FIG. 14, the interpolation coefficient corresponding to each fluorescent color is illustrated.

  In this example, interpolation coefficients β_R, β_G, β_B including the direction of adjusting the output values S_R, S_G, S_B are shown. The center point is set as ± 0, and the outer side is set as an interpolation coefficient of + and the inner side is set as − as the reference.

  As an example, in the case of a yellow fluorescent color, the values of the interpolation coefficients β_R, β_G> 0 are set. Thereby, the output value S_G and the output value S_R are adjusted to increase. On the other hand, the interpolation coefficient β_B <0 is set. Thereby, the output value S_B is adjusted in a decreasing direction. The same applies to the case of other fluorescent colors.

Interpolation coefficients β_R, β_G, β_B corresponding to the estimated fluorescent color are selected.
Next, the fluorescence correction processing unit 52 calculates correction amounts ΔB, ΔR, and ΔG based on the adjustment amount α and the interpolation coefficient β calculated in steps S6 and S8.

Specifically, the following correction formula can be used.
ΔB = β_B × α
ΔR = α × β_α
ΔG = α × β_α
Next, the fluorescence correction processing unit 52 corrects the RGB data (step S12).

Specifically, it is calculated by the following formula.
I_B = S_B + ΔB
I_R = S_R + ΔR
I_G = S_G + ΔG
Thereby, the fluorescence correction processing unit 52 calculates correction values I_B, I_G, and I_B.

Then, the fluorescence correction process ends (END).
Then, the edge detection unit 54 and the color correction unit 56 reproduce the image information based on the correction values I_R, I_G, and I_B from the fluorescence correction processing unit 52, execute necessary input image processing, and finally Output as image data.

  The adjustment described with reference to FIG. 11 is executed by this method, and the color reproducibility of the fluorescent color can be improved and the readability can be improved.

  In the above description, the adjustment coefficient α is not described for a method for adjusting each RGB data, but it is also possible to calculate the adjustment coefficients α_R, α_G, α_B for each RGB data and execute the fluorescence correction process. It is.

  As described above, in the image reading device 4, the photoelectric conversion element output when each of the RGB light sources is turned on is corrected using the photoelectric conversion element output value obtained when the light source corresponding to the ultraviolet component is turned on.

  In the present example, the interpolation coefficient β close to the estimated color is calculated using the interpolation table of FIG. 14 described above, but the variation of the interpolation coefficient is small in the case of between blue and cyan colors, but other colors ( For example, in the case of red), the interpolation coefficient varies greatly. Therefore, when the color type (parameter) for setting the interpolation coefficient β of the interpolation table is a color close to red, it may be increased compared to blue or cyan. Thereby, the color reproducibility of the fluorescent color can be improved and the readability can be improved.

<F. Advantage>
In the image reading apparatus employing the one-line CIS reading method according to the present embodiment, in addition to three general light sources (R light source, G light source, B light source), a UV light source that generates ultraviolet light, and a reading target By adding a cut filter that cuts off the ultraviolet light contained in the reflected light, it is possible to irradiate the reading object with light from each light source using the fluorescent component generated from the reading object when irradiated with ultraviolet light. By correcting the obtained image signal, the color reproducibility of the fluorescent color can be improved and the readability can be improved.

  According to the image reading apparatus adopting the one-line CIS reading method according to the present embodiment, the same color reproducibility as the CCD reading method and the three-line CIS reading method is realized for the drawing range of the reading target including the fluorescent dye. Therefore, it is possible to realize a configuration that is equivalent in performance and lower in cost than these reading methods.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 2 main-body part, 3 automatic document conveyance part, 4 image reading apparatus, 5 image forming part, 6 paper feeding part, 7 paper discharge part, 8 operation panel, 21 slit glass, 22 1st reading part (reading) Part), 23 platen glass, 24 scanning unit, 25 travel unit, 30 document transport path, 31 paper feed tray, 32 pickup roller, 33 paper feed roller pair, 34 intermediate roller pair, 35 registration roller pair, 36 first transport roller Pair, 37 Second transport roller pair, 38 Second reading section, 39 Third transport roller pair, 40 Paper discharge roller, 41 Paper discharge tray, 42, 43 Reading roller, 46 Support rail, 50 Image processing section, 52 Fluorescence correction Processing unit, 54 edge detection unit, 56 color correction unit, 60 controller board, 62 timing control unit, 64 light emission control unit, 6 Signal acquisition unit, 70 document, 72, 82, 92 drawing portion, 220 light emitting unit, 220B, 220G, 220R, 220UV light source, 222 light guide, 224, 224R, 224G, 224B imaging lens, 226, 226R, 226G, 226B line sensor, 227R, 227G, 227B color filter, 228 cut filter.

Claims (12)

An image reading apparatus for reading image information from a reading target,
A red light source that generates light including a red wavelength component, a green light source that generates light including a green wavelength component, a blue light source that generates light including a blue wavelength component, and an ultraviolet light source that generates light including an ultraviolet component A light emitting unit including
A light guide for uniformizing the light generated from the light emitting unit and irradiating the reading target;
A photoelectric conversion unit that outputs a value indicating the luminance of each region of a reflected image generated by light irradiation to the reading object;
A cut filter that is disposed on the optical path from the reading object to the photoelectric conversion unit, and blocks an ultraviolet component;
By generating any light from the light emitting unit in a predetermined order and processing each output value sequentially output from the photoelectric conversion unit in association with wavelength characteristics of the corresponding light, A control unit that generates image information to be read;
The process of generating the image information of the reading target estimates the fluorescent color of the reading target, and irradiates the reading target with light from the red light source, the green light source, and the blue light source according to the estimated fluorescent color An image reading apparatus that adjusts at least one of output values that are sometimes output.   The process of generating the image information of the reading target is based on at least one output value among output values output when the reading target is irradiated with light from the red light source, the green light source, and the blue light source. The image reading apparatus according to claim 1, wherein adjustment is performed according to a correction amount corresponding to an output value when the reading target is irradiated with light from the ultraviolet light source.   In the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is around cyan or blue, the coefficient of the correction amount is small, and the fluorescent color of the reading target is around red The image reading apparatus according to claim 2, wherein when it is estimated that the correction amount coefficient is set large.   In the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is orange, the output value when the reading target is irradiated with light from the red light source is increased, The image reading apparatus according to claim 1, wherein an output value when the reading target is irradiated with light from the green light source is decreased and an output value when the reading target is irradiated with light from the blue light source is decreased. .   The process of generating the image information of the reading target increases an output value when the reading target is irradiated with light from the red light source when it is estimated that the fluorescent color of the reading target is pink. The image reading apparatus according to claim 1, wherein an output value when the reading target is irradiated with light from the green light source is reduced.   In the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is yellow, the output value when the reading target is irradiated with light from the red light source is increased, The image reading apparatus according to claim 1, wherein an output value when the reading target is irradiated with light from the green light source is increased, and an output value when the reading target is irradiated with light from the blue light source is decreased. .   In the process of generating the image information of the reading target, when it is estimated that the fluorescent color of the reading target is green, the output value when the reading target is irradiated with light from the green light source is increased. The image reading apparatus according to claim 1, wherein an output value when the reading target is irradiated with light from the blue light source is decreased.   The process of generating the image information of the reading target increases an output value when the reading target is irradiated with light from the blue light source when it is estimated that the fluorescent color of the reading target is blue. The image reading apparatus according to claim 1.   The process of generating the image information of the reading target increases an output value when the reading target is irradiated with light from the green light source when it is estimated that the fluorescent color of the reading target is cyan. The image reading apparatus according to claim 1, wherein an output value when the reading object is irradiated with light from the blue light source is increased. A table having a plurality of parameters for setting a coefficient of the correction amount according to the estimated fluorescent color;
For multiple parameters of the table,
Many are set for the color of the reading target fluorescent color similar to red,
The image reading apparatus according to claim 3, wherein the reading target fluorescent color is set to be small for colors similar to cyan and blue. An image reading device for reading image information from a reading target;
An image forming unit that forms an image based on image information read by the image reading device;
The image reading device includes:
A red light source that generates light including a red wavelength component, a green light source that generates light including a green wavelength component, a blue light source that generates light including a blue wavelength component, and an ultraviolet light source that generates light including an ultraviolet component A light emitting unit including
A light guide for uniformizing the light generated from the light emitting unit and irradiating the reading target;
A photoelectric conversion unit that outputs a value indicating the luminance of each region of a reflected image generated by light irradiation to the reading object;
A cut filter that is disposed on the optical path from the reading object to the photoelectric conversion unit, and blocks an ultraviolet component;
By generating any light from the light emitting unit in a predetermined order and processing each output value sequentially output from the photoelectric conversion unit in association with wavelength characteristics of the corresponding light, A control unit that generates image information to be read,
The process of generating the image information of the reading target estimates the fluorescent color of the reading target, and irradiates the reading target with light from the red light source, the green light source, and the blue light source according to the estimated fluorescent color An image forming apparatus that adjusts at least one of output values that are sometimes output. An image reading method for reading image information from a reading target,
A red light source that generates light including a red wavelength component, a green light source that generates light including a green wavelength component, a blue light source that generates light including a blue wavelength component, and an ultraviolet light source that generates light including an ultraviolet component Including a step of generating any light in a predetermined order from a light emitting unit including the light emitted from the light emitting unit is made uniform by a light guide and irradiated to the reading object, A cut filter for blocking the ultraviolet component is placed on the optical path from the reading target to the photoelectric conversion unit,
Storing the output value indicating the brightness of each region of the reflected image that is sequentially output from the photoelectric conversion unit and caused by light irradiation to the reading object in association with the wavelength characteristic of the corresponding light;
Generating image information to be read from the stored output value,
The step of generating image information to be read includes
Estimating the reading target fluorescent color;
Adjusting at least one output value among output values respectively output when the reading object is irradiated with light from the red light source, the green light source, and the blue light source according to the estimated fluorescent color. Image reading method.