JP2013258496A - Image reading device, image forming device, and image reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve excellent white correction without switching a white reference plate.SOLUTION: An image reading device comprises: an irradiation unit which irradiates a reference plate with light including visible light and invisible light having a shorter wavelength than the visible light; a reference plate which is provided with a fluorescent region absorbing the invisible light and producing fluorescence and a non-fluorescent region reflecting the invisible light, and reflects light; a sensor which converts the light reflected by the reference plate and a read object into an electric signal; a filter which blocks the invisible light reflected by the reference plate for the sensor; and a processing unit which performs arithmetic processing for correcting a light quantity of the irradiation unit on the basis of the electric signal obtained by converting the light reflected by the fluorescent region by the sensor and the electric signal obtained by converting the light reflected by the non-fluorescent region by the sensor.

Description

  The present invention relates to an image reading apparatus, an image forming apparatus, and an image reading method.

  Conventionally, an image formed on a sheet to be read may include a fluorescent region that fluoresces. The fluorescent region of the image is formed by, for example, a fluorescent pen. In addition, a paper using a fluorescent material that absorbs and fluoresces ultraviolet rays so as to make the yellowing of the paper inconspicuous is also known. Some techniques for discriminating fluorescent regions included in an image are also known.

  For example, Patent Document 1 discloses a document based on a combination of a color of a light source and a color of an image sensor, such as determining a yellow or green fluorescent region based on an output of a green sensor when blue light is irradiated. An image reading apparatus for discriminating a fluorescent region formed in the above is disclosed. Patent Document 1 discloses shading correction of fluorescence image data for reducing the influence of the luminance distribution of the light source in the main scanning direction and the variation of each image sensor of the image sensor.

  However, when a fluorescent reference plate as a fluorescent reference in the fluorescent region and a white reference plate as a white reference are installed adjacent to each other in the sub-scanning direction, There was a problem that the reference plate and the white reference plate had to be moved and switched.

  The present invention has been made in view of the above, and an object thereof is to realize good white correction without switching a white reference plate.

  In order to solve the above-described problems and achieve the object, the present invention absorbs the invisible light and fluoresces it by irradiating light including visible light and invisible light having a shorter wavelength than the visible light. A reference plate for reflecting the light by providing a fluorescent region and a non-fluorescent region for reflecting the invisible light; a sensor for converting the light reflected by the reference plate and the reading object into electrical signals; and the reference plate A filter that blocks the invisible light reflected by the sensor, an electrical signal converted by the sensor from the light reflected by the fluorescent region, and the light converted by the non-fluorescent region. And a processing unit that performs arithmetic processing for correcting the light amount of the irradiation unit based on the electrical signal.

  The present invention also provides an irradiation unit for irradiating visible light and light including invisible light having a shorter wavelength than the visible light, a fluorescent region that absorbs and fluoresces the invisible light, and non-fluorescent light that reflects the invisible light. A reference plate that is provided with a region and reflects the light; a sensor that converts the light reflected by the reference plate and the reading object into electrical signals; and the invisible light that is reflected by the reference plate is transmitted to the sensor. Based on the filter for blocking, the electrical signal converted by the sensor from the light reflected by the fluorescent region, and the electrical signal converted by the sensor for the light reflected by the non-fluorescent region, An image that forms an image based on a processing unit that performs arithmetic processing to be corrected, an electrical signal obtained by converting the light reflected by the reading target by the sensor, and a processing result of the processing unit It has a generating unit, a.

  Further, the present invention provides a fluorescent region that absorbs invisible light having a wavelength shorter than that of visible light and fluoresces, and a non-fluorescent region that reflects the invisible light and serves as a reference for correcting the light amount. Irradiating light including visible light and the invisible light, blocking the invisible light reflected by the reference plate, converting the light reflected by the reference plate into an electrical signal, and the fluorescent region Performing a calculation process for correcting the amount of the light irradiated on the reference plate based on the electrical signal obtained by converting the reflected light and the electrical signal obtained by converting the light reflected by the non-fluorescent region; and reading And a step of generating image data based on the electric signal obtained by converting the light reflected by the object and the calculation processing result.

  According to the present invention, there is an effect that good white correction can be realized without switching the white reference plate.

FIG. 1 is a schematic front view of the configuration of an image forming apparatus according to an embodiment. FIG. 2 is a configuration diagram illustrating a configuration of the reading unit and its periphery. FIG. 3 is a flowchart illustrating the operation of the image reading apparatus that performs white correction. FIG. 4 is a timing chart showing the irradiation timing of each LED of the light source and the driving timing of the sensor. FIG. 5 is a flowchart illustrating an operation example of the image forming apparatus. FIG. 6 is a configuration diagram illustrating a configuration of a first modification of the reading unit. FIG. 7 is a configuration diagram illustrating a configuration of a second modification of the reading unit. FIG. 8 is a configuration diagram illustrating a configuration of a third modification of the reading unit.

  Exemplary embodiments of an image forming apparatus will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic front view of the configuration of an image forming apparatus 1 according to an embodiment. As shown in FIG. 1, the image forming apparatus 1 includes a main body housing 2 that includes a paper feeding unit 3, a transport unit 4, an image forming unit 5, a fixing unit 6, a paper discharge unit 7, and an image reading device 8. ing. The image forming apparatus 1 is further provided with a manual feed tray 10, a document table 11, a paper discharge tray 12, an operation unit, a control unit (not shown), and the like. The operation unit is a user interface, and the control unit has a function as a computer.

  A plurality of sheets P are set in the sheet feeding unit 3, and the conveyance unit 4 includes a registration roller 21 and the like. The paper feed unit 3 adjusts the timing of the paper P by the registration rollers 21 and conveys the paper P to the image forming unit 5. The transport unit 4 also adjusts the timing of the paper P set on the manual feed tray 10 by the registration rollers 21 and transports the paper P to the image forming unit 5.

  The image forming unit 5 includes a charging unit, an optical writing unit 23, a developing unit, a transfer unit, a cleaning unit, and the like around a photosensitive member 22 that is rotationally driven counterclockwise in FIG. The charging unit uniformly charges the photoreceptor 22 (for example, charges to −1200 V). In the image forming unit 5, the light writing unit 23 irradiates the photosensitive member 22 uniformly charged by the charging unit with light for lighting control based on the image data of the document read by the image reading device 8. An electrostatic latent image is formed by eliminating the charge on the surface of the photoreceptor 22 irradiated with light. The image forming unit 5 forms a toner image by causing the developing unit to attach toner to the photosensitive member 22 on which the electrostatic latent image is formed.

  The image forming unit 5 transfers the toner image formed on the photosensitive member 22 to the paper P conveyed from the paper feeding unit 3 by the transfer unit, and separates the transferred paper P by the separation charger to fix the toner image. 6 to transport. Further, the image forming unit 5 cleans the residual toner on the photoconductor 22 that has been transferred by the cleaning unit, discharges the cleaned photoconductor 22 by the charge removing unit, and then uniformly charges it by the charging unit. Image formation is performed again.

  In the image forming apparatus 1, a paper folding device 30 is connected to the back side of the main body housing 2. The paper folding device 30 performs folding processing such as end face folding and bellows folding on the paper P on which an image has been formed. The paper folding device 30 includes a connection portion 31 with the main body housing 2, an ear folding portion 32 that folds the ears of the paper P, a bellows folding portion 33 that folds the paper P in a bellows shape in the transport direction, and a transport that changes the transport direction by 90 °. A switching device 34, a cross folding device (not shown), a reversing device 35 for reversing the front and back, a paper P rotated by 90 °, for example, a rotating device 36 for switching A4 landscape to A4 portrait and folded paper P are discharged. A tray 37 or the like for stacking is provided.

  The image forming apparatus 1 discharges the paper P on which the image forming unit 5 forms an image and the fixing unit 6 fixes the image to the paper folding device 30 when the paper discharge unit 7 performs post-processing such as paper folding. When paper folding is not performed, the paper is discharged to the paper discharge tray 12 by a switching claw (not shown).

  The paper folding device 30 folds corners of the paper P by the ear fold 32 when the paper P on which the image is formed is folded, and then folds it into a bellows by the bellows fold 33 to change the conveyance. Transport to the apparatus 34 is performed. The folding device 30 switches the conveyance direction of the fed paper P by the conveyance switching device 34, folds the short side direction of the paper P folded bellows by the cross folding device, and turns the front and back of the paper P by the reversing device 35. The paper P is reversed, and the paper direction is rotated by the rotating device, so that the paper P is stacked on the tray 37.

  The image reading device 8 described above includes a front roller pair 41, a reading unit 42, a rear roller pair 43, and the like positioned on the near side with respect to the document conveyance direction (sub-scanning direction). A plurality of documents set on the document table 11 are separated from the document table 11 and sent out to the front roller pair 41 one by one. The front roller pair 41 conveys the document to the reading unit 42. The reading unit 42 reads the conveyed document. The rear roller pair 43 discharges the document read by the reading unit 42.

  Next, the reading unit 42 and its periphery will be described in detail. FIG. 2 is a configuration diagram showing the configuration of the reading unit 42 and its surroundings. As shown in FIG. 2, the reading unit 42 includes an irradiation unit 50, a reference plate 51, a filter 52, an equal magnification lens 53, and a sensor 54. That is, the reading unit 42 may be configured using a contact image sensor.

  The irradiation unit 50 includes a light source 55 and a light guide unit 56. The light source 55 includes three LEDs (Light Emitting Diodes) that emit light of the three primary colors of red (R), green (G), and blue (B) equally, and LEDs that emit ultraviolet light (X). This is a so-called multichip light-emitting element. The light source 55 is configured such that each LED can emit light independently under the control of a control unit (not shown) and emits light to the light guide unit 56. That is, the light source 55 emits light including visible light (visible light) and ultraviolet light (ultraviolet light). The light source 55 may have a single-chip configuration combining an ultraviolet LED and an RGB phosphor, or emit light including invisible light having a shorter wavelength than visible light other than ultraviolet light. Also good. The light guide 56 irradiates the reference plate 51 with the light emitted from the light source 55 by guiding the light emitted from the light source 55 in the main scanning direction (direction of arrow A).

  The reference plate 51 is a white reference plate extending in the main scanning direction in which a fluorescent region 57 in which a fluorescent material is applied to a reading region for reading an object to be read and a non-fluorescent region 58 in which no fluorescent material is applied is provided. The light irradiated by the irradiation unit 50 is reflected. In the reading area, a document (reading object) conveyed on the upper surface side of the reference plate 51 in the sub-scanning direction (direction substantially orthogonal to the main scanning direction) by the above-described front roller pair 41 and rear roller pair 43 is read by the reading unit 42. Is set in the central portion of the reference plate 51.

  When the fluorescent region 57 is irradiated with ultraviolet rays, the fluorescent material absorbs the ultraviolet rays (ultraviolet light) to shift from the ground state to the excited state, and light having a wavelength longer than that of the absorbed ultraviolet rays when returning to the ground state ( Fluorescent by emitting visible light such as blue). The non-fluorescent regions 58 are provided at both ends of the reference plate 51 and reflect the light irradiated by the irradiation unit 50.

  The filter 52 has a length in the main scanning direction that is substantially the same as that of the fluorescent region 57 and is disposed between the fluorescent region 57 and the equal-magnification lens 53 and has a wavelength shorter than that of blue (B) light. Shut off. That is, the filter 52 blocks the ultraviolet light (X) that is irradiated by the irradiation unit 50 and reflected by the reference plate 51 to the equal-magnification lens 53 (sensor 54).

  The equal-magnification lens 53 is a lens array in which a plurality of lenses are arranged in the main scanning direction, and forms an image of reflected light from the reading target (or the reference plate 51) on the sensor 54. The sensor 54 is a line sensor in which a plurality of solid-state imaging devices such as a CCD (Charge Coupled Device) are arranged in the main scanning direction, and reflects reflected light from a reading target (or a reference plate 51) via the equal magnification lens 53. Receives light and converts it into an electrical signal. The sensor 54 outputs the converted electrical signal to the processing unit 59 via an A / D converter (not shown). The processing unit 59 performs a calculation process described later for correcting the light amount of the irradiation unit 50.

  As described above, in the reading unit 42, the lengths of the filter 52 and the fluorescent region 57 in the main scanning direction are shorter than the lengths of the sensor 54 and the equal magnification lens 53 in the main scanning direction.

  Next, white correction of the image reading device 8 will be described. Since the distribution of the ultraviolet region differs depending on the illumination, in order to match the appearance and the color and brightness of the read image, it is necessary to control the light amount of the fluorescence by adjusting the light amount of the LED in the ultraviolet region.

  In general, in an image reading apparatus, variation in the amount of light of a light source (variation between bright and dark elements), change over time of the light source (the LED has a light amount that decreases with a lifetime, and a fluorescent lamp has a low amount of light at a low temperature) and the illuminance that illuminates an original from the light source Variation of the distribution of light (a light guide or a diffusion plate is made as uniform as possible, but cannot be made uniform). The image reading apparatus uses a white reference plate having a uniform density and color to obtain the variation by reading reflected light when the white reference plate is irradiated with light. The image reading apparatus corrects normal read data using the acquired data, thereby realizing image reading that is not affected by variations. In addition, the image reading apparatus also uses correction on the white reference plate to correct variation in sensitivity between reading sensor elements and variation in light quantity due to a lens that forms an image of a document on the reading sensor. In the embodiment, a separate correction process is performed for the sensitivity variation between the elements of the sensor 54 and the light amount variation due to the equal-magnification lens 53 that forms an image of the document on the sensor 54.

  FIG. 3 is a flowchart showing the operation of the image reading apparatus 8 that performs white correction (shading correction). The image reading device 8 performs white level adjustment (white correction) when the power is turned on or before document reading. As shown in FIG. 3, in step 100 (S100), the image reading apparatus 8 performs black level adjustment. In the black level adjustment, the image reading device 8 turns off the light source 55 (LED) and acquires the black level of the sensor 54 in units of sensor pixels (stored as a black level correction value).

  In step 102 (S102), the image reading apparatus 8 performs white level adjustment. In the white level adjustment, the image reading device 8 sequentially turns on each LED of the light source 55 as shown in FIG. 4 and converts the reflected light from the reference plate 51 into an electrical signal by the sensor 54. FIG. 4 is a timing chart showing the irradiation timing of each LED of the light source 55 and the driving timing of the sensor 54. As shown in FIG. 4, the image reading device 8 sequentially switches and irradiates each RGB color and X (ultraviolet light) LED, and causes the sensor 54 to receive RGB reflected light. The sensor 54 outputs the charge accumulated by light reception for each pixel in synchronization with the reference signal (Clock). Then, the image reading device 8 adjusts the lighting time or the like so that the light amount of each LED input through the sensor 54 is lower than the input upper limit of an A / D converter (not shown). The adjusted white level of each (ultraviolet) LED is acquired in units of sensor pixels (saved as a white level correction value).

  In step 104 (S104), the image reading device 8 turns off each LED. The white level adjusted for each LED is used as a correction value by the processing unit 59.

  Next, arithmetic processing performed by the processing unit 59 will be described. Since an area corresponding to the reading area of the reference plate 51 (fluorescence area 57) is coated with a fluorescent material that absorbs ultraviolet light and fluoresces blue, the fluorescent light is turned on by turning on the LED (X) of the light source 55. Region 57 fluoresces blue. Since the ultraviolet light in the reading area is cut by the filter 52, the fluorescent blue light is received by the sensor 54. However, since the fluorescent material is not applied outside the reading area (non-fluorescent area 58) and the area where the filter 52 is not provided for the equal magnification lens 53 does not fluoresce, ultraviolet light is received by the sensor 54. Is done.

  Therefore, the image reading device 8 can acquire the variation in the light amount of the light source 55 (the variation between the bright element and the dark element) and the variation in the distribution of illuminance that illuminates the document from the light source 55 using the fluorescent region 57 of the reference plate 51. it can. In addition, the image reading device 8 reflects the time-dependent change of the light source 55 (the LED has a reduced light amount at the end of life, and the fluorescent lamp has a low light amount at a low temperature) that is reflected by a region not coated with a fluorescent material (non-fluorescent region 58). Can be obtained by light. Then, the image reading device 8 corrects the acquired data of the reading region (fluorescent region 57) using the acquired data outside the reading region (non-fluorescent region 58), thereby obtaining good correction data of the ultraviolet light source. Can do. Note that light (visible light) other than ultraviolet light is received by the sensor 54 regardless of the presence or absence of the fluorescent material and the filter 52. The processing unit 59 performs arithmetic processing for correcting the light amount of the irradiation unit 50 as follows using the correction data of the ultraviolet light source.

  For example, S0 (n, m) is read data (10 bits) acquired by image reading, Sk (m) is a black level correction value acquired by black level adjustment, 0 is dark, and 1023 is bright. Here, n indicates a sub-scanning line number, and m indicates a main scanning pixel number. Here, the image data S1 (n, m) subjected to black correction is calculated by the following equations 1-3. When distinguishing between red, green, blue, and ultraviolet light in each image data, the name of the image data includes either r, g, b, or x. It can be distinguished.

Blue: Sb1 (n, m) = Sb0 (n, m) -Sk (m) (1)
Green: Sg1 (n, m) = Sg0 (n, m) −Sk (m) (2)
Red: Sr1 (n, m) = Sr0 (n, m) -Sk (m) (3)

  In addition, the white level correction value acquired by the white level adjustment is defined as Sw (m). Here, the image data S2 (n, m) subjected to white correction is calculated by the following equations 4-6.

Blue: Sb2 (n, m) = Sb1 (n, m) ÷ 1023 × Sbw (m)
... (4)
Green: Sg2 (n, m) = Sg1 (n, m) ÷ 1023 × Sgw (m)
... (5)
Red: Sr2 (n, m) = Sr1 (n, m) ÷ 1023 × Srw (m)
... (6)

  Further, the white level correction value of the reading region (fluorescent region 57) acquired by adjusting the white level of ultraviolet light is Sxw0 (m). Further, the white level correction value outside the reading area (non-fluorescent area 58) acquired by adjusting the white level of ultraviolet light is set to Sxw (mi). However, mi is a number outside the reading area of the main scanning pixel number.

  Here, using the average value Sxw (mi0) of the plurality of pixels of Sxw (mi) at a certain time point and the average value Sxw (mi1) of the plurality of pixels of Sxw (mi) at the next time point, the reading area The white level correction value of (fluorescent region 57) is corrected by Sxw0 (m) as shown in Equation 7 below. In the following expression 7, the corrected white level correction value is Sxw1 (m). Further, the image data Sx2 (n, m) of the ultraviolet light subjected to white correction is calculated by the following equation 8.

Sxw1 (m) = Sxw0 (m) × Sxw (mia1) ÷ Sxw (mia0)
... (7)
Ultraviolet light: Sx2 (n, m) = Sx1 (n, m) ÷ 1023 × Sxw1 (m)
... (8)

  The reading data of the ultraviolet light is the same as it looks by combining it with the reading data of the blue color that fluoresces. Therefore, the blue black correction and the white correction are further corrected by the following equations 9 and 10.

Sb1 (n, m) = Sb0 (n, m) −Sk (m) (9)
Sb2 (n, m) = Sb1 (n, m) ÷ 1023 × Sbw (m) + Sx2 (n, m)
(10)

  Next, the operation of the image forming apparatus 1 will be described. FIG. 5 is a flowchart illustrating an operation example of the image forming apparatus 1. As shown in FIG. 5, in step 200 (S200), in the image forming apparatus 1, the irradiation unit 50 irradiates the reference plate 51 with light, for example, when the power is turned on or before document reading.

  In step 202 (S202), the sensor 54 converts the reflected light from the reference plate 51 into an electrical signal.

  In step 204 (S204), the processing unit 59 performs the above-described arithmetic processing for correcting the light amount of the irradiation unit 50 in accordance with the electrical signal converted by the sensor 54.

  In step 206 (S206), the image forming apparatus 1 stores the result of the arithmetic processing in S204 in a storage unit (not shown).

  In step 208 (S208), in the image forming apparatus 1, the irradiation unit 50 irradiates the reading target such as a document with light.

  In step 210 (S210), the sensor 54 converts the reflected light from the reading object into an electrical signal.

  In step 212 (S212), the image forming apparatus 1 corrects the image data generated from the electrical signal converted in the process of S210 by using the calculation result stored in the process of S206, whereby the light amount of the irradiation unit 50 is corrected. Image data (image) to which correction is applied is generated.

(First Modification of Reading Unit 42)
Next, a first modification of the reading unit 42 will be described. FIG. 6 is a configuration diagram illustrating a configuration of a first modification of the reading unit 42. In the first modification of the reading unit 42 shown in FIG. 6, components that are substantially the same as the components of the reading unit 42 shown in FIG. 2 are denoted by the same reference numerals. In the first modification of the reading unit 42, the non-fluorescent region 58 is provided only on the counter light source 55 side of the reference plate 51. That is, the non-fluorescent region 58 is provided at a position farther from the light source 55 than the fluorescent region 57.

  That is, in the first modified example of the reading unit 42, the sensor 54 receives reflected light from the non-fluorescent region 58 at a position farther from the light source 55 than the fluorescent region 57 including the reading region, so that it is less than the reading region. An arithmetic process for correcting the light amount of the irradiation unit 50 can be performed in accordance with the reflected light of the irradiated light from the non-fluorescent region 58. Accordingly, it is possible to increase the S / N ratio of the read data and form a high quality image.

(Second Modification of Reading Unit 42)
Next, a second modification of the reading unit 42 will be described. FIG. 7 is a configuration diagram illustrating a configuration of a second modification of the reading unit 42. In the second modification of the reading unit 42 shown in FIG. 7, components that are substantially the same as the components of the reading unit 42 shown in FIG. 2 are denoted by the same reference numerals. In the second modification of the reading unit 42, the non-fluorescent regions 58 are provided so as to be alternately arranged with the fluorescent regions 57 in the main scanning direction also in the reading region.

  In the second modification of the reading unit 42, since the fluorescent regions 57 and the non-fluorescent regions 58 are alternately arranged in the main scanning direction, quenching can be avoided. For example, since the fluorescent region 57 and the non-fluorescent region 58 each have a predetermined width, the white level correction value of ultraviolet rays is divided into a relatively large value and a small value, but each of a bright part and a dark part with a predetermined width The two white level correction values of ultraviolet rays can be obtained from the two straight lines connecting the peak values. Therefore, a good white level correction value can be obtained from the fluorescent region 57 and the non-fluorescent region 58 while avoiding quenching.

(Third Modification of Reading Unit 42)
Next, a third modification of the reading unit 42 will be described. FIG. 8 is a configuration diagram illustrating a configuration of a third modification of the reading unit 42. In the third modification of the reading unit 42 shown in FIG. 8, the same reference numerals are given to the substantially same components as those of the second modification of the reading unit 42 shown in FIG. It is. The third modification of the reading unit 42 is different from the second modification of the reading unit 42 in that the position of the reference plate 51 is shifted from the focal position of the equal-magnification lens 53.

  In the third modified example of the reading unit 42, in addition to the effects of the second modified example of the reading unit 42, fluctuations in the main scanning direction of the white level correction value of the ultraviolet light can be smoothed.

  As described above, the image forming apparatus 1 can acquire the reading data of the white reference plate including the temporal change of the fluorescent material by the fluorescent region 57 and can acquire the temporal change data of the light source 55 by the non-fluorescent region 58. Using this data, it is possible to calculate read data that does not include temporal variation of the fluorescent material.

  In the above embodiment, the image forming apparatus 1 of the present invention has been described as an example in which the image forming apparatus 1 is applied to a multi-function machine having at least two functions among a copy function, a printer function, a scanner function, and a facsimile function. Any image forming apparatus including an image reading apparatus such as a scanner apparatus or a facsimile apparatus can be applied.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body housing | casing 3 Paper feeding part 4 Conveying part 5 Image forming part 6 Fixing part 7 Paper discharge part 8 Image reading apparatus 11 Document base 12 Paper discharge tray 41 Front roller pair 42 Reading part 43 Rear roller pair 50 Irradiation Unit 51 reference plate 52 filter 53 equal magnification lens 54 sensor 55 light source 56 light guide unit 57 fluorescent region 58 non-fluorescent region 59 processing unit

JP 2010-273301 A

Claims (7)

Irradiation unit for irradiating visible light and light including invisible light whose wavelength is shorter than visible light, and
A fluorescent region that absorbs the invisible light and fluoresces, and a non-fluorescent region that reflects the invisible light, and a reference plate that reflects the light;
Sensors that convert the light reflected by the reference plate and the reading object into electrical signals, respectively.
A filter that blocks the invisible light reflected by the reference plate from the sensor;
Computation processing for correcting the light quantity of the irradiation unit based on an electrical signal obtained by the sensor converting the light reflected by the fluorescent region and an electrical signal obtained by the sensor converting the light reflected by the non-fluorescent region. A processing unit to perform,
An image reading apparatus. The fluorescent region and the filter are:
Provided in a reading region for reading the reading object in the main scanning direction;
The non-fluorescent region is
The image reading apparatus according to claim 1, wherein the image reading apparatus is provided outside the reading area extending in a main scanning direction of the reference plate. The irradiation unit is
A light source that is provided on one end side of the reference plate and emits the light;
A light guide that guides the light emitted by the light source so that the light is applied to the reference plate and the reading target;
Have
The non-fluorescent region is
The image reading apparatus according to claim 2, wherein the image reading apparatus is provided on the other end side of the reference plate with respect to the fluorescent region. The fluorescent region and the non-fluorescent region are:
The image reading apparatus according to claim 1, wherein a plurality of the image reading apparatuses are provided so as to be alternately arranged in the main scanning direction. A lens for imaging the light reflected by the reference plate on the sensor;
The reference plate is
The image reading apparatus according to claim 4, wherein the image reading apparatus is disposed at a position shifted from a focal position of the lens. Irradiation unit for irradiating visible light and light including invisible light whose wavelength is shorter than visible light, and
A fluorescent region that absorbs the invisible light and fluoresces, and a non-fluorescent region that reflects the invisible light, and a reference plate that reflects the light;
Sensors that convert the light reflected by the reference plate and the reading object into electrical signals, respectively.
A filter that blocks the invisible light reflected by the reference plate from the sensor;
Computation processing for correcting the light quantity of the irradiation unit based on an electrical signal obtained by the sensor converting the light reflected by the fluorescent region and an electrical signal obtained by the sensor converting the light reflected by the non-fluorescent region. A processing unit to perform,
An image forming unit that forms an image based on an electric signal obtained by the sensor converting the light reflected by the reading target and a calculation processing result of the processing unit;
An image forming apparatus. Visible light and invisible light with respect to a reference plate that is provided with a fluorescent region that absorbs invisible light having a shorter wavelength than visible light and fluoresces, and a non-fluorescent region that reflects the invisible light and corrects the amount of light. Irradiating light containing
Blocking the invisible light reflected by the reference plate and converting the light reflected by the reference plate into an electrical signal;
Based on an electrical signal obtained by converting the light reflected by the fluorescent region and an electrical signal obtained by converting the light reflected by the non-fluorescent region, an arithmetic processing for correcting the light amount of the light irradiated on the reference plate is performed. Process,
A step of generating image data based on the electric signal obtained by converting the light reflected by the reading object and the calculation processing result;
An image reading method comprising:

Images