JP6070932B2 - Image inspection apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image inspection apparatus that reads an image on a recording sheet and inspects an image formed on the recording sheet, and an image forming apparatus including the image inspection apparatus. The present invention relates to an image inspection apparatus and an image forming apparatus capable of reading glossiness of recording paper.

  2. Description of the Related Art In recent years, an image forming apparatus that is provided with an image inspection apparatus that reads an image again from a printed recording sheet and inspects the print state has been widely used because of a demand for high reproducibility in an image after printing. The image inspection apparatus has a configuration similar to that of an image reading apparatus that reads an image of a document, thereby reading an image on a recording sheet after printing. By the way, an image reading apparatus has been proposed that can detect the gloss and color of an image of a document by utilizing a difference in optical path between regular reflection light and diffuse reflection light (Patent Document 1 and Patent Document 2). reference).

  The image reading device (imaging device) disclosed in Patent Document 1 is provided with means for selectively blocking the optical path of specularly reflected light from an original and the light of diffusely reflected light from the original. Only one of the reflected lights is incident on the line sensor (solid-state imaging device). On the other hand, the image reading apparatus disclosed in Patent Document 2 is provided with a mechanism for combining an optical system for forming an optical path of specularly reflected light with an optical system that constitutes an optical path of diffusely reflected light, so that the reading position of the document On the other hand, by sliding the mechanism, only one of the regular reflection light and the diffuse reflection light is made incident on the image sensor (solid-state imaging device).

JP 2006-279228 A JP 2010-245918 A

  As described above, each of the image reading devices disclosed in Patent Document 1 and Patent Document 2 selects one of the optical paths of regular reflection light and diffuse reflection light, and reads the gloss or color of the image. . For this reason, the image reading apparatuses of Patent Document 1 and Patent Document 2 need to provide an optical system suitable for each optical path of regular reflection light and diffuse reflection light, and to provide a mechanism for selecting each optical system. The configuration becomes complicated. Further, since the image reading apparatuses of Patent Document 1 and Patent Document 2 are not configured to read the color and gloss of the image at a time, in order to read the color and gloss of the image, two reading operations are performed on one original. It was necessary to do it once.

  In view of such a problem, an object of the present invention is to provide an image inspection apparatus and an image forming apparatus that can read the color and gloss of an image with a single reading operation and can simplify the structure thereof. And

  In order to achieve the above object, an image inspection apparatus according to the present invention includes a light source for irradiating light on an image formed on a recording paper, and an optical path for allowing specularly reflected light from the light source to pass on the recording paper. In an image inspection apparatus comprising an optical system that configures and a solid-state imaging device that receives light guided by the optical system, the image inspection apparatus is disposed on an optical path from the light source to the recording paper, and emits light emitted from the light source. A first polarizer that transmits light linearly polarized in a predetermined polarization direction toward the recording paper, and a polarization direction of light received by the solid-state imaging device, provided as part of the optical system. A second polarizer that regulates, and a polarization switching control unit that controls whether the optical system transmits light from the optical system to the solid-state imaging device by specularly reflected light from the recording paper. When transmission of reflected light is prohibited While the specularly reflected light is shielded by the second polarizer and the solid-state image sensor receives diffuse reflected light other than the specularly reflected light and operates in a colorimetric mode for outputting color image data, When the transmission of the regular reflection light is permitted by the polarization switching control unit, the solid-state imaging device receives the regular reflection light without the regular reflection light being blocked by the second polarizer, and gloss It operates in the gloss measurement mode for outputting image data, and alternately operates at predetermined time intervals in the color measurement mode and the gloss measurement mode while passing a sheet of recording paper. The color image data and gloss image data of the image are output simultaneously.

  In this image inspection apparatus, the colorimetry mode and the gloss measurement mode may be switched for each predetermined pixel of one pixel or more along the sub-scanning direction of the recording paper. Further, the color measurement mode and the gloss measurement mode may be switched within one pixel along the sub-scanning direction of the recording paper.

  Each of the image inspection apparatuses includes a mechanism that is controlled by the polarization switching control unit and that rotates the second polarizer in a plane that is perpendicular to the optical path connecting the optical system and the solid-state imaging device. Then, the color measurement mode and the gloss measurement mode may be switched by rotating the second polarizer by the mechanism and switching the transmission axis direction of the second polarizer.

  In each of the above image inspection apparatuses, a mechanism that slides the second polarizer on a plane that is controlled by the polarization switching control unit and that is perpendicular to an optical path connecting the optical system and the solid-state imaging device. And switching the colorimetry mode and the gloss measurement mode by sliding the second polarizer in a direction perpendicular to the main scanning direction of the solid-state imaging device. Absent.

  Further, each of the image inspection apparatuses includes a liquid crystal element that is controlled by the polarization switching control unit and disposed on a light incident side of the second polarizer, and depending on whether a voltage is applied to the liquid crystal element. The color measurement mode and the gloss measurement mode may be switched by controlling whether or not the polarization direction of the light transmitted through the liquid crystal element can be rotated.

  In the colorimetry mode, the transmission axis direction of the second polarizer is perpendicular to the polarization direction of the regular reflection light, so that the regular reflection light is shielded and only diffuse reflection light is transmitted. Can be made. In the gloss measurement mode, the specularly reflected light can be transmitted by intersecting the transmission axis direction of the second polarizer with the polarization direction of the specularly reflected light at an angle smaller than 90 °. At this time, the transmission axis direction of the second polarizer in the gloss measurement mode may be the same as the polarization direction of the regular reflection light.

  In each of the image inspection apparatuses described above, the direction of light irradiated from the light source to the recording paper through the first polarizer is 45 ° or less with respect to the normal line of the image inspection surface of the recording paper. It does n’t matter.

  The image forming apparatus according to the present embodiment includes any one of the above-described image inspection apparatuses, and thereby obtains color image data and glossy image data at a time for a printed recording paper image. can do.

  According to the present invention, since the configuration is such that the gloss measurement mode and the color measurement mode are alternately operated during a single pass of the recording paper, in order to measure the color and gloss of the image formed on the recording paper. It is not necessary to perform the reading operation on the recording paper twice. Therefore, unlike the prior art, it is not necessary to install two image inspection devices in the image forming apparatus in order to measure the color and gloss of the image formed on the recording paper, and the image forming apparatus can only be miniaturized. In addition, the time required for measuring each of color and gloss can be shortened, and the conveyance of recording paper can be simplified. Further, since the gloss measurement mode and the color measurement mode are switched depending on whether or not the regular reflection light based on the light linearly polarized by the first polarizer is received, it is necessary to configure a plurality of optical paths for the measurement in each mode. In addition, the number of optical components to be used can be reduced, and the configuration of the optical system can be simplified.

FIG. 1 is a schematic configuration diagram showing an internal configuration of an image forming apparatus which is a basic configuration of the present invention. FIG. 2 is a block diagram illustrating a schematic configuration of an image inspection apparatus in the image forming apparatus illustrated in FIG. 1. These are the figures which show the relationship of the transmission axis direction of each of 1st and 2nd polarizer, Comprising: (a)-(c) is a figure which shows the relationship in glossiness measurement mode, (d) is colorimetry mode. It is a figure which shows the relationship in. FIG. 6 is a diagram for explaining the operation of the image inspection apparatus in the first example of mode switching timing, in which (a) shows the relationship between the timing for switching between the colorimetric mode and the gloss measurement mode and the reading position of the recording paper. In the figure, (b) is a diagram showing the relationship between the switching timing of the colorimetric mode and the gloss measurement mode and the operation of the solid-state imaging device, and (c) is a diagram showing the image data output from the solid-state imaging device. is there. FIG. 10 is a diagram for explaining the operation of the image inspection apparatus in the second example of the mode switching timing, wherein (a) shows the relationship between the switching timing of the colorimetric mode and the gloss measurement mode and the reading position of the recording paper. In the figure, (b) is a diagram showing the relationship between the switching timing of the colorimetric mode and the gloss measurement mode and the operation of the solid-state imaging device, and (c) is a diagram showing image data output from the solid-state imaging device. is there. FIG. 10 is a diagram for explaining the operation of the image inspection apparatus in the third example of the mode switching timing, in which (a) shows the relationship between the switching timing of the color measurement mode and the gloss measurement mode and the reading position of the recording paper. In the figure, (b) is a diagram showing the relationship between the switching timing of the colorimetric mode and the gloss measurement mode and the operation of the solid-state imaging device, and (c) is a diagram showing the image data output from the solid-state imaging device. is there. FIG. 2 is a schematic diagram showing a part of a configuration of a control device in the image forming apparatus of FIG. 1. These are the schematic diagrams which show the structure around the 2nd polarizer of the image inspection apparatus in the image forming apparatus of the 1st Embodiment of this invention. These are the schematic diagrams which show the structure around the 2nd polarizer of the image inspection apparatus in the image forming apparatus of the 2nd Embodiment of this invention. These are the schematic diagrams which show another structure of the 2nd polarizer periphery of the image inspection apparatus in the image forming apparatus of the 2nd Embodiment of this invention. These are the schematic diagrams which show the structure around the 2nd polarizer of the image inspection apparatus in the image forming apparatus of the 3rd Embodiment of this invention.

<Basic Configuration in Embodiment for Implementing the Present Invention>
Hereinafter, a basic configuration in an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are given to the same parts or corresponding parts. In addition, this basic configuration describes a configuration common to the configurations in the following embodiments. The image forming apparatus according to the present invention, including the following embodiments, may be any apparatus provided with both an image reading mechanism and an image inspection mechanism. For example, a copying machine, a printer or a multifunction machine having a copying function is available. It does not matter.

1. Configuration of Image Forming Apparatus The configuration of the image forming apparatus 1 will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an internal configuration of the image forming apparatus 1.

  An image forming apparatus 1 shown in FIG. 1 stores an image reading apparatus 2 that reads an image from a document and a recording paper 10 for printing an image, and feeds the recording paper 10 into the image forming apparatus 1. The mechanism 3, the image forming device 4 that transfers the toner image to the recording paper 10 based on the original image data read by the image reading device 2, and the toner image transferred to the recording paper 10 by the image forming device 4 The fixing device 5 for fixing, the image inspection device 6 for inspecting the printing state of the recording paper 10 on which the toner image is fixed by the fixing device 5, and the recording paper 10 after printing inspected by the image inspection device 6 A paper discharge mechanism 7 for discharging the paper.

  The image reading apparatus 2 forms an image on the solid-state imaging device 22, a light source 21 that irradiates light on the document, a solid-state image sensor 22 that receives reflected light from the document and converts it into an electrical signal, and the reflected light from the document. The imaging lens 23, the original glass plate 24 on which the original is placed, the reflecting mirror 25 that reflects the light from the light source 21 and irradiates the surface of the original, and the reflected light from the original is guided to the imaging lens 23. The reflectors 26A to 26C and a reference plate 27 for generating a correction value for shading correction are provided.

  The imaging lens 23 and the solid-state imaging device 22 each have a plurality of elements in a direction (corresponding to “main scanning direction”) perpendicular to the document reading direction (corresponding to “sub-scanning direction”). It consists of a group of elements arranged for each. Further, in the solid-state imaging device 22, since a primary color or complementary color filter is installed on the light receiving surface of each pixel, the light of the light transmitted through the color filter is received by each pixel device, so Read the image as a color image. Further, the light source 21 and the reflecting mirrors 25 and 26A are provided in the first slider portion 211, and the reflecting mirrors 26B and 26C are provided in the second slider portion 212. The first and second slider parts 211 and 212 are simultaneously moved in the sub-scanning direction by a moving mechanism (not shown) such as a rail and a motor, so that the sub-scanning direction of the original placed on the surface of the original glass plate 24 is increased. Reading to is performed.

  In the image reading apparatus 2 configured as described above, when reading an image of a document, the document is placed on a document glass plate 24 of a document placing table, or an automatic document feeder (ADF: Auto Document Feeder). ) To the original glass plate 24. At this time, when the irradiation light from the light source 21 and the reflected light from the reflecting mirror 25 are irradiated to the reading position of the document, the reflected light from the document with respect to this irradiation light is incident on the reflecting mirror 26A. Then, the reflected light from the reflecting mirror 26A is sequentially reflected by the reflecting mirrors 26B and 26C, guided to the imaging lens 23, and the reflected light from the original is transmitted through the imaging lens 23, and the solid-state imaging device 22 takes an image. The image is formed on the area. The solid-state imaging device 22 outputs an electric signal corresponding to the amount of received light for each line at a constant interval in accordance with the reading width along the sub-scanning direction, so that a two-dimensional original image based on the image on the original is obtained. Data is generated.

  Further, the image reading device 2 moves the first slider portion 211 and the second slider portion 212 to move the first slider portion 211 to a position directly below the reference plate 27 before performing the image reading operation of the document. The reference plate 27 is read. Thereby, the correction value for carrying out the shading correction | amendment of the output value of the electric signal output from the solid-state image sensor 22 to a main scanning direction is generable. Therefore, by performing shading correction based on this correction value for the electrical signal output from the solid-state image pickup device 22, variation in the amount of light in the main scanning direction by the light source 21 can be suppressed in the generated document image data.

  As shown in FIG. 1, the paper feed mechanism 3 includes a paper feed cassette 31 that stores a recording paper 10 on which an image is printed, a paper feed roller pair 32 that takes out the recording paper 10 stored in the paper feed cassette 31, and Is provided. Further, on the downstream side of the paper feed mechanism 3, a transport roller pair 33 for transporting the recording paper 10 fed from the paper feed cassette 31 to the recording paper transport path by the paper feed roller pair 32 to the image transfer mechanism 4 is provided. ing. The recording paper transport path represents a transport path from the paper feed cassette 31 to the paper discharge tray 72 along which the recording paper 10 on which an image is printed by the image forming mechanism is transported. The sheet feeding mechanism 3 configured in this manner takes out the recording sheets 10 stored in the sheet feeding cassette 31 one by one by the rotation of the pair of sheet feeding rollers 32 and supplies the recording sheets 10 to the recording sheet conveyance path. Then, the recording paper 10 discharged from the paper feeding cassette 31 is conveyed to the image forming device 4 by the rotation of the conveying roller 33 installed on the downstream side of the paper feeding mechanism 3 along the conveying direction of the recording paper 10. The

  The image forming device 4 is carried on the photosensitive drums 41 to 44 on which electrostatic latent images of each color of Y (Yellow) M (Magenta) C (Cyan) K (Key tone) are formed, and the photosensitive drums 41 to 44, respectively. Further, an intermediate transfer unit 45 to which toner of each color of YMCK is transferred, and a secondary transfer roller 46 that transfers the toner transferred to the intermediate transfer unit 45 to the recording paper 10 are provided. At this time, although not shown, each of the photosensitive drums 41 to 44 is provided with a charger for charging the photosensitive drums 41 to 44 by corona discharge or the like, and a laser beam or the like to the charged photosensitive drums 41 to 44. An exposure device that forms an electrostatic latent image by irradiation, a developing device that charges the YMCK toners by stirring and adheres them to the photosensitive drums 41 to 44, and the photosensitive drums 41 to 44 after being transferred to the intermediate transfer unit 45. And a cleaning member for removing the toner remaining on the toner.

  The intermediate transfer unit 45 also includes an intermediate transfer belt 451 to which toner of each color of YMCK is transferred from the photosensitive drums 41 to 44, a driving roller 452 and a driven roller 453 for rotating the intermediate transfer belt 451, and photosensitive drums 41 to 44, respectively. Are provided with primary transfer rollers 454 to 457 installed at positions facing each other with the intermediate transfer belt 451 interposed therebetween. Further, the intermediate transfer unit 45 includes a cleaning member (not shown) for removing toner remaining on the intermediate transfer belt 451 without being transferred to the recording paper 10 from the surface of the intermediate transfer belt 451. The secondary transfer roller 46 is installed at a position facing the driving roller 452 with the intermediate transfer belt 451 interposed therebetween.

  In the image forming apparatus 4 configured as described above, the photosensitive drums 41 to 44 have electrostatic latent images of each color of YMCK on the surfaces of the photosensitive drums 41 to 44 based on the document image data acquired by the image reading mechanism 2. Is formed, the charged YMCK color toners are carried on the electrostatic latent images of the photosensitive drums 41 to 44, respectively. In the intermediate transfer unit 45, the intermediate transfer belt 451 is rotated by the driving roller 452, and the toner images of each color of YMCK carried on the photosensitive drums 41 to 44 are primary transfer rollers 454 to 457 to which a predetermined potential is applied. Is transferred to the intermediate transfer belt 451 by the electrostatic force.

  At this time, the intermediate transfer belt 451 sequentially transfers the toner images of the respective colors from the photosensitive drums 41 to 44 in the order of YMCK by the portions where the toner images to be transferred to the recording paper 10 are sequentially contacted with the photosensitive drums 41 to 44. Is done. Further, YMCK toner images on the surfaces of the photosensitive drums 41 to 44 are formed in the order of the photosensitive drums 41 to 44 in accordance with the timing of transferring the toner to the intermediate transfer belt 451.

  The toner image formed by transferring the YMCK color toners onto the surface of the intermediate transfer belt 451 moves to a position where the surface of the intermediate transfer belt 451 on which the toner image is formed is opposed to the secondary transfer roller 46. Then, the image is transferred to the recording paper 10 sandwiched between the intermediate transfer belt 451 and the secondary transfer roller 46. The transfer of the toner image onto the recording paper 10 is realized by the charged toner of each color being attracted to the secondary transfer roller 46 by the voltage applied to the secondary transfer roller 46. The recording paper 10 onto which the toner image is transferred is not only conveyed from the paper feeding mechanism 3 to the secondary transfer roller 46, but also includes a recording paper reversing mechanism (not shown) for reversing the recording paper 10. In the case where it is provided on the downstream side of 5, it is conveyed from the secondary transfer roller 46 by the recording paper reversing mechanism.

  The fixing device 5 includes a heating roller 51 including a halogen lamp for heating to fix the toner on the recording paper 10, and a pressure roller 52 that presses the recording paper 10 while sandwiching the heating roller 51 and the recording paper 10. Is provided. In the fixing device 5, the recording paper 10 onto which the toner image is transferred by the image forming device 4 is transported by guidance by a pair of transport rollers 53 installed between the image forming device 4 and the fixing device 5. The recording paper 10 on which the toner image has been transferred passes between the heating roller 51 and the pressure roller 52, thereby receiving the heating by the heating roller 51 and the pressure by the heating roller 51 and the pressure roller 52. . As a result, the transferred toner image is fixed on the recording paper 10, and an image based on the original image data is printed on the recording paper 10. The heating roller 51 may be one in which the surface of the heating roller 51 is heated by generating an eddy current on the surface by electromagnetic induction.

  The paper discharge mechanism 7 is provided outside the image forming apparatus 1 and the paper discharge roller 71 for discharging the recording paper 10 that has passed through the image inspection apparatus 6 to the outside of the image forming apparatus 1. A paper discharge tray 72 for receiving the printed recording paper 10. The paper discharge mechanism 7 configured as described above guides the recording paper 10 on which the toner image is fixed on the recording surface by the fixing device 5 by the drive of the paper discharge roller 71 from the image inspection device 6. Then, the paper is discharged to a paper discharge tray 72 outside the image forming apparatus 1.

2. Configuration of Image Inspection Apparatus As shown in FIG. 2, the image inspection apparatus 6 receives a light source 61 that irradiates light onto a recording paper 10 on which an image is printed, and receives reflected light from the recording paper 10 and converts it into an electrical signal. The solid-state imaging device 62, the imaging lens 63 that forms an image of the reflected light from the recording paper 10 on the solid-state imaging device 62, and recording that moves in the sub-scanning direction (corresponding to the conveyance direction in the recording paper conveyance path Q). A glass plate 64 with which the image recording surface of the paper 10 abuts, reflecting mirrors 65A to 65C for guiding reflected light from the recording paper 10 to the imaging lens 63, and a reference plate for generating correction values for shading correction 66, a first polarizer 67 that aligns light emitted from the light source 61 with linearly polarized light, and a second polarizer 68 that determines the polarization direction of the light to be imaged on the solid-state imaging device 62.

  The reflecting mirror 65A is disposed on the optical path of specularly reflected light that is reflected at an angle substantially equal to the incident angle of the light from the light source 61. In other words, with reference to the normal line of the recording paper 10 at the reading position P1, the reflection is performed at a position where the straight line connecting the light source 61 and the reading position P1 and the straight line connecting the reflecting mirror 65A and the reading position P1 are symmetric. A mirror 65A is installed. A first polarizer 67 is disposed on the optical path of the light from the light source 61 that connects the light source 61 and the reading position P1. For example, the light source 61 is irradiated with light having directivity, such as a light emitting diode (LED) light source and a light guide member that uniformly emits light from the LED light source. Preferably.

  When reading the image on the recording paper 10, the light from the light source 61 passes through the first polarizer 67, so that the light that is linearly polarized in the polarization direction regulated by the transmission axis of the first polarizer 67 is changed. The reading position P1 is irradiated. When the irradiation light whose polarization direction is aligned by the first polarizer 67 enters the recording paper 10, the regular reflection light and the diffuse reflection light with respect to the irradiation light are reflected at the reading position P1 of the recording paper 10 and reflected by the reflecting mirror. Proceed on the optical path to 65A. The incident direction of the light incident on the recording paper 10 from the light source 61 through the first polarizer 67 is preferably 45 ° or less with respect to the normal line of the paper surface (image inspection surface) of the recording paper 10.

  At this time, since the optical path toward the reflecting mirror 65A coincides with the optical path of the regular reflection light at the reading position P1, only a part of the diffuse reflection light traveling in all directions is reflected unlike the regular reflection light. Incident on the mirror 65A. Therefore, the light intensity of the specularly reflected light incident on the reflecting mirror 65A is stronger than the light intensity of the diffusely reflected light also incident on the reflecting mirror 65A. The regular reflection light is linearly polarized light having the same polarization direction as that regulated by the first polarizer 67, while the diffuse reflection light is non-polarized light whose polarization direction is not fixed. . The regular reflection light and diffuse reflection light reflected by the reflecting mirror 65A are guided to the imaging lens 63 by the reflecting mirrors 65B and 65C, and pass through the imaging lens 63 so as to form an image in the imaging region of the solid-state imaging device 62. . That is, the reflecting mirrors 65A to 65C and the imaging lens 63 constitute an optical system that allows regular reflected light from the recording paper 10 to pass therethrough, and a first polarizer 67 is provided as part of the optical system. .

  On the optical path from the imaging lens 63 to the solid-state imaging device 62, as described above, the second polarizer 68 capable of switching the transmission axis direction is disposed, and the second polarizer 68 is arranged in the transmission axis direction. The light in the polarization direction along the light enters the solid-state image sensor 62. That is, by switching the transmission axis direction of the second polarizer 68, either regular reflection light or diffuse reflection light transmitted through the imaging lens 63 can be selectively incident on the solid-state imaging device 62. Accordingly, when the transmission axis direction of the second polarizer 68 is a direction that blocks the light in the polarization direction of the specularly reflected light, the diffuse reflected light is transmitted through the second polarizer 68 and is incident on the solid-state image sensor 62. The On the other hand, when the transmission axis direction of the second polarizer 68 is not the direction that blocks the light in the polarization direction of the regular reflection light, the regular reflection light mainly passes through the second polarizer 68 and is incident on the solid-state image sensor 62. The

  At this time, when the specularly reflected light is blocked by the second polarizer 68, the transmission axis direction of the second polarizer 68 is relative to the transmission axis direction of the first polarizer 67 as shown in FIG. The second polarizer 68 is disposed so as to be vertical. As a result, the specularly reflected light whose polarization direction is perpendicular to the transmission axis of the second polarizer 68 is shielded by the second polarizer 68, so that only the diffusely reflected light is incident on the solid-state imaging device 62. The Then, the solid-state imaging device 62 performs a photoelectric conversion operation on the incident diffuse reflected light, and outputs image data representing the color component of the image formed on the recording paper 10 to the control device 8 (see FIG. 4). To do. In the following description, the operation mode when the color component image data is output from the solid-state imaging device 62 is referred to as a “colorimetric mode”.

  On the other hand, as shown in FIG. 3A or 3B, the second polarizer 68 is arranged such that the transmission axis direction of the second polarizer 68 is parallel or intersects with the transmission axis direction of the first polarizer 67. 3 or as shown in FIG. 3C, the optical path from the imaging lens 63 to the solid-state image sensor 62 is shifted from the optical path so that all the light transmitted through the imaging lens 63 is incident on the solid-state image sensor 62. The second polarizer 68 is disposed at the position. Thus, by arranging the second polarizer 68, the regular reflected light is incident on the solid-state imaging device 62 without the regular reflected light being blocked by the second polarizer 68. Then, the solid-state imaging device 62 performs a photoelectric conversion operation on the incident regular reflection light, and outputs image data representing the gloss component of the image formed on the recording paper 10 to the control device 8 (see FIG. 7). To do. In the following description, the operation mode when outputting the gloss component image data from the solid-state image sensor 62 is referred to as a “gloss measurement mode”.

  That is, as shown in FIG. 3A, when the transmission axis direction of the second polarizer 68 is matched with the transmission axis direction of the first polarizer 67, the polarization direction of the regular reflection light is the transmission of the second polarizer 68. Since it coincides with the axial direction, the specularly reflected light passes through the second polarizer 68, and a part of the diffusely reflected light (diffuse reflected light whose change direction does not coincide with the transmission axis of the second polarizer 68) is shielded. . Further, as shown in FIG. 3B, when the transmission axis direction of the second polarizer 68 intersects with the transmission axis direction of the first polarizer 67 at a non-perpendicular and non-perpendicular angle, the second polarizer 68 The luminous flux of regular reflection light that passes through 68 is reduced as compared with the case of FIG. 3A, but is sufficiently larger than the luminous flux of diffuse reflection light that passes through the second polarizer 68. By determining the transmission axis direction of the second polarizer 68 as shown in FIG. 3B, the amount of specular light incident on the solid-state image sensor 62 can be reduced. It is possible to prevent the amount of received light from exceeding the dynamic range of the solid-state imaging device. Further, as shown in FIG. 3C, when there is no transmission by the second polarizer 68, the regular reflected light and the diffuse reflected light are incident on the solid-state imaging device 62. The amount of light is larger than that of diffusely reflected light. From the above, by arranging the second polarizer 68 as shown in FIGS. 3A to 3C, the solid-state imaging device 62 can output image data based on the amount of specularly reflected light. .

  As described above, the image inspection apparatus 6 switches between the colorimetric mode and the gloss measurement mode by switching the transmission axis direction of the second polarizer 68, and outputs image data in each mode from the solid-state image sensor 67. . When one sheet of recording paper 10 passes through the image inspection apparatus 6 and the image is read, the color measurement mode and the gloss measurement mode are switched at a predetermined timing. Accordingly, the image inspection apparatus 6 performs image data in the color measurement mode (hereinafter referred to as “color image data”) and an image in the gloss measurement mode by a single read operation on one recording paper 10. Data (hereinafter referred to as “glossy image data”) can be output. The timing for switching between the color measurement mode and the gloss measurement mode in the image inspection apparatus 6 operating in this way will be described below.

3. First Example of Mode Switching Timing In this example, as shown in FIG. 4A, the image inspection apparatus 6 performs color measurement mode and gloss measurement mode for each pixel in the sub-scanning direction of the recording paper 10. Switch. That is, as shown in FIG. 4B, when the recording paper 10 passes the reading position of the image inspection apparatus 6, the color measurement mode is applied to the image on the first line (first pixel in the sub-scanning direction). When the reading operation is performed, color image data for one line is output from the solid-state imaging device 62. When the color image data for one line is output, the image inspection apparatus 6 switches the color measurement mode to the gloss measurement mode. As a result, the image inspection apparatus 6 performs a reading operation in the gloss measurement mode for the image of the next second line, and the gloss image data for one line is output from the solid-state imaging device 62.

  By setting the mode switching timing in this way, for example, when the solid-state imaging device 62 performs the photoelectric conversion operation and the output operation (horizontal scanning) for each line, as shown in FIG. Each time the mode is switched, a photoelectric conversion operation and an output operation are performed. Therefore, as shown in FIG. 4C, the serial data for each pixel output from the solid-state imaging device 62 to the subsequent circuit is one line of color image data D1 and one line of glossy image data D2. It consists of image data that appears alternately.

4). Second Example of Mode Switching Timing In this example, as shown in FIG. 5A, the image inspection apparatus 6 performs a color measurement mode and a gloss measurement mode every two pixels in the sub-scanning direction of the recording paper 10. Switch. That is, as shown in FIG. 5B, when the recording paper 10 passes through the reading position of the image inspection apparatus 6, the first and second lines (first and second pixels in the sub-scanning direction) of the image are processed. When the reading operation is performed in the color measurement mode, the color image data of the first and second lines are sequentially output from the solid-state imaging device 62. When the color image data of the second line is output, the image inspection apparatus 6 switches the color measurement mode to the gloss measurement mode. As a result, the image inspection apparatus 6 performs the reading operation in the gloss measurement mode for the next 3rd and 4th line images, and the 3rd and 4th line gloss image data from the solid-state image sensor 62 in order. Is output.

  By setting the mode switching timing in this manner, as in the first example, for example, when the solid-state imaging device 62 performs the photoelectric conversion operation and the output operation (horizontal scanning) for each line, FIG. ), Photoelectric conversion operation and output operation are alternately performed for two lines during one mode. Therefore, as shown in FIG. 5C, the serial data for each pixel output from the solid-state image sensor 62 to the subsequent circuit is color image data D1 for two lines and glossy image data D2 for two lines. It consists of image data that appears alternately.

5. Third Example of Mode Switching Timing In this example, as shown in FIG. 6A, the image inspection apparatus 6 scans one pixel in the sub-scanning direction of the recording paper 10 (the recording paper 10 is equivalent to one pixel). The color measurement mode and the gloss measurement mode. That is, as shown in FIG. 6B, when the recording paper 10 passes the reading position of the image inspection apparatus 6, the color measurement mode is applied to the image on the first line (first pixel in the sub-scanning direction). When the reading operation is performed, first, color image data for one line is output from the solid-state imaging device 62. When the color image data for one line is output, the image inspection apparatus 6 switches the color measurement mode to the gloss measurement mode in order to acquire gloss image data for the same first line image. As a result, the image inspection apparatus 6 performs a reading operation in the gloss measurement mode on the same image of the first line, and the gloss image data for one line is output from the solid-state imaging device 62.

  By setting the mode switching timing in this way, for example, when the solid-state imaging device 62 performs the photoelectric conversion operation and the output operation (horizontal scanning) for each line, as shown in FIG. A photoelectric conversion operation and an output operation are performed for each mode, and a reading operation for two lines is performed for the same line. Therefore, as shown in FIG. 6C, the serial data for each pixel output from the solid-state imaging device 62 to the subsequent circuit is one line of color image data D1 and one line of gloss image data. D2 and image data appearing alternately.

  When operating in this example by switching between the color measurement mode and the gloss measurement mode, the conveyance speed of the recording paper 10 is reduced to, for example, a speed that is ½ or less compared to the operation in only one mode. Alternatively, the data values of the output color image data and glossy image data may be amplified, for example, twice or more. Further, not only in this example but also in the first example and the second example described above, the conveyance speed of the recording paper 10 may be changed according to the time required for switching between the colorimetric mode and the gloss measurement mode. Absent.

  When the image inspection apparatus 6 performs a reading operation on one sheet of recording paper 10, the color inspection mode and the gloss measurement mode are switched as in the first to third examples described above, so that the recording sheet 10 Color image data and glossy image data can be output simultaneously. The image inspection apparatus 6 performs the reading operation of the reference plate 67 in each of the color measurement mode and the gloss measurement mode before performing the image reading operation on the recording paper 10. Thereby, in the control device 8 (see FIG. 7), the electrical signal output from the solid-state imaging device 62 when the reading operation is performed with respect to the reference plate 67 in each of the colorimetry mode and the gloss measurement mode is used for shading correction in each mode. The data is stored in advance as business data.

  Therefore, the control device 8 (see FIG. 7) uses the shading correction data in the color measurement mode and the gloss measurement mode for the color image data and the gloss image data output from the solid-state image sensor 62, respectively. By performing the shading correction, it is possible to suppress variations in the amount of light in the main scanning direction by the light source 61. The reference plate 67 may be configured such that the white plate and the blackboard are adjacent to each other in the conveyance direction of the recording paper 10 and can be slid in the conveyance direction of the recording paper 10. This generates shading correction data for each of the color measurement mode and the gloss measurement mode for each of the white plate portion and the blackboard portion of the reference plate 67, and for each of the color image data and the gloss image data, shading according to the respective black and white standards. Corrections can be made.

6). Components for Controlling the Operation of the Image Inspection Apparatus The image inspection apparatus 6 that performs the image reading operation of the recording paper 10 by switching between the color measurement mode and the gloss measurement mode as described above is shown in FIG. The operation is controlled by receiving a signal from the control device 8 having the configuration. Further, the image inspection device 6 controlled by the control device 8 outputs the color image data and the gloss image data generated by the solid-state image sensor 62 to the control device 8. A configuration for controlling the operation of the image inspection apparatus 6 will be described with reference to a block diagram shown in FIG. The control device 8 has a configuration for communicating with each device and the mechanisms 2 to 7 including the image inspection device 6 in the image forming apparatus 1 and controlling the operation of each device and the mechanisms 2 to 7. However, in FIG. 7, a configuration related to the image inspection apparatus 6 is shown, and the other configuration and description are omitted.

  The control device 8 includes a CPU (Central Processing Unit) 81 that executes various arithmetic processes and controls, a ROM (Read Only Memory) 82 that stores control programs, and a RAM (Random Access Memory) that temporarily stores arithmetic data. ) 83, an image data generation unit 84 that generates color image data and glossy image data from the electrical signal output from the solid-state imaging device 62, and a shading correction that is a correction value for the shading correction by the image data generation unit 84 A mode for selectively selecting a shading correction value calculation unit 85 for generating data, a “switching mode” for switching between the color measurement mode and the gloss measurement mode, and a “single mode” for operating only in each mode. A selection unit 86, an input / output interface 87 for transmitting / receiving signals to / from the image inspection apparatus 6, and each of the controllers 8 It includes a bus 88 for transmitting and receiving signals in order to establish communication between the lock and.

  On the other hand, the image inspection apparatus 6 includes a light emission control unit 610 configured by a PWM (Pulse Width Modulator) circuit for setting the light emission amount of the light source 61 and an imaging control for controlling an imaging operation in the solid-state imaging device 62. 620, an output amplifier 621 that amplifies the electric signal output from the solid-state imaging device 62, and a polarization switching control unit 680 for controlling the transmission axis switching operation of the second polarizer 68. In addition, when the light source 61 is comprised by LED (light Emitting Device), you may comprise as a PWM circuit etc. which polarize the duty ratio of the pulse current which gives the light emission control part 610 to LED.

  When the control unit 8 configured as described above is operated by an operation unit (not shown) of the image forming apparatus 1 and the “switching mode” is designated by the user, the “input / output interface 87” of the control apparatus 8 The CPU 81 is notified that the “switching mode” has been designated. Therefore, when the CPU 81 gives a command to the mode selection unit 86 to operate the image inspection apparatus 6 in the switching mode, the mode selection unit 86 stores that it operates in the switching mode. The mode selection unit 86 generates a control signal for causing the image inspection apparatus 6 to operate at the mode switching timing of any of the first to third examples described above, and the input / output interface 87 sends the control signal to the image inspection apparatus 6. Output.

  In the image inspection device 6, a control signal from the mode selection unit 86 of the control device 8 is given to each of the imaging control unit 620 and the polarization switching control unit 680. Thereby, the image inspection apparatus 6 switches the colorimetry mode and the gloss measurement mode at the mode switching timing shown in the first to third examples described above, and at the same time, the image pickup operation is performed by the solid-state image pickup device 62. Image data for one frame composed of image data and glossy image data is generated. That is, the color image data and the gloss image data generated by the solid-state image sensor 62 are alternately output to the control device 8 through the output amplifier 621 according to the mode switching timing.

  When the control device 8 receives the image data obtained by reading from the single recording paper 10 by the image inspection device 6 from the input / output interface 87, the control device 8 sends the image data to the image data generation unit 84. The shading correction value calculation unit 85 of the control device 8 has already input image data when the image inspection device 6 has read the reference plate 67 in each of the colorimetry mode and the gloss measurement mode. Shading correction values for each of the color mode and gloss measurement mode are calculated and stored. Then, the image data generation unit 84 processes the image data for one frame given from the image inspection apparatus 6 in synchronization with the input timing of the image data of each line, so that the color image data and the glossy image are processed. Separate data. Each of the color image data and the gloss image data is subjected to shading correction based on the shading correction value acquired in advance by the shading correction value calculation unit 85.

  Further, when the color image data and the gloss image data are output at the mode switching timing based on the first example and the second example, the values of the respective modes that have not been read in the sub-scanning direction are interpolated. Thus, color image data and gloss image data for one frame are generated. That is, when the image inspection apparatus 6 operates at the mode switching timing of the first example, the color image data is image data that does not include image data of even lines represented by the second line. At this time, by using the image data of the odd lines sandwiching the image data of the even lines, the image data of the even lines is generated by, for example, linear interpolation calculation processing, so that the color image data for one frame is obtained. Generate.

  On the contrary, the gloss image data is image data that does not include image data of odd lines represented by the first line. At this time, the image data of the odd line is generated using the image data of the even line sandwiching the image data of the odd line, thereby generating the gloss image data for one frame. Incidentally, when the image inspection apparatus 6 operates at the mode switching timing of the third example, such an interpolation process is not necessary. As described above, each unit of the control device 8 operates to generate color image data and glossy image data based on the image data output when the recording paper 10 is read by the image inspection device 6.

  On the other hand, when the user operates an operation unit (not shown) of the image forming apparatus 1 and “single mode” is designated, “single mode” is designated through the input / output interface 87 of the control device 8. Is notified to the CPU 81. At this time, the operation mode of the image inspection apparatus 6 is designated by receiving an operation from the user and further selecting one of the “color measurement mode” and the “gloss measurement mode”. Therefore, when the CPU 81 gives a command to the mode selection unit 86 to operate the image inspection apparatus 6 independently of either “color measurement mode” or “gloss measurement mode”, the mode selection unit 86 selects “color measurement mode”. ”And“ Glossy measurement mode ”are stored.

  When notified of the operation in the “colorimetry mode”, the control device 8 generates a control signal for operating in the “colorimetry mode” in the mode selection unit 86, and the image inspection apparatus 87 through the input / output interface 87. 6 is output. Thus, the image inspection apparatus 6 gives the control signal received from the control apparatus 8 to the imaging control unit 620 and the polarization switching control unit 680, thereby fixing the second polarizer 68 in the “colorimetry mode” and recording paper. 10 reading operations are performed. Therefore, the imaging control unit 620 controls the imaging operation of the solid-state imaging device 62 to generate color image data for one frame, which is output to the control device 8 through the output amplifier 621. In the control device 8, when the color image data received from the image inspection device 6 by the input / output interface 87 is given to the image data generation unit 84, based on the shading correction value acquired in advance by the shading correction value calculation unit 85. Shading correction is applied.

  Further, when notified that the control device 8 operates in the “gloss measurement mode”, the control device 8 generates a control signal for operating in the “gloss measurement mode” in the mode selection unit 86, and the image is input from the input / output interface 87. Output to the inspection device 6. Thereby, the image inspection apparatus 6 gives the control signal received from the control apparatus 8 to the imaging control unit 620 and the polarization switching control unit 680, thereby fixing the second polarizer 68 in the “gloss measurement mode” and recording paper. 10 reading operations are performed. Accordingly, the imaging control unit 620 controls the imaging operation of the solid-state imaging device 62, generates glossy image data for one frame, and outputs it to the control device 8 through the output amplifier 621. In the control device 8, when the gloss image data received from the image inspection device 6 by the input / output interface 87 is given to the image data generation unit 84, based on the shading correction value acquired in advance by the shading correction value calculation unit 85. Shading correction is applied.

  Thus, when each of the “switching mode” or “single mode” is designated and the image inspection apparatus 6 operates, the image inspection apparatus 6 outputs color image data and the case where gloss image data is output. The amplification factor of the output amplifier 621 may be changed. That is, when the image inspection device 6 outputs color image data, the amplification factor of the output amplifier 621 is increased, while when the image inspection device 6 outputs glossy image data, the amplification factor of the output amplifier 621. Make it smaller. Thereby, each of the color image data and the gloss image data generated by the control device 8 can be processed as data of the same gradation. Note that the amplification of the data values of the color image data and the glossy image data is not performed by the output amplifier 621 but may be performed by the image data generation unit 84 of the control device 8.

  Each of the following embodiments describes an image forming apparatus having the above-described image forming apparatus 1 as a basic configuration. The configuration for the image inspection apparatus to switch between the color measurement mode and the gloss measurement mode will be described in more detail. To do. Therefore, in the following embodiments, details will be described focusing on the configuration of the second polarizer 68 in the image inspection apparatus 6.

<First Embodiment>
An image forming apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 8 is a schematic diagram showing a configuration around the second polarizer 68 of the image inspection apparatus in the image forming apparatus of the present embodiment.

  As shown in FIG. 8, the image inspection apparatus 6 in the image forming apparatus 1 of the present embodiment has a mechanism for rotating the second polarizer 68 whose transmission axis is a fixed direction. Then, the image is rotated on a plane perpendicular to the optical path from the imaging lens 63 to the solid-state imaging device 62. That is, the outer peripheral surface of the second polarizer 68 is meshed with the gear 682 rotated by the motor 681, so that the transmission axis of the second polarizer 68 rotates according to the rotation of the motor 681. The rotation operation of the motor 681 is controlled by the PWM circuit in the polarization switching control unit 680.

  As described above, the image inspection apparatus 6 includes the configuration in which the second polarizer 68 is rotated by the motor 681, so that in the gloss measurement mode, the transmission axis direction of the second polarizer 68 is set as illustrated in FIG. As shown in 3 (b), while allowing the specularly reflected light to be sufficiently transmitted, the transmission axis direction of the second polarizer 68 is set to be parallel or intersecting with the polarization direction of the specularly reflected light, while in the colorimetric mode, As shown in FIG. 3D, the light is perpendicular to the polarization direction of the regular reflection light so that the regular reflection light is blocked. At this time, the rotation of the motor 681 may be rotated in a fixed direction every time the mode is switched, or may be forward and reverse alternately every time the mode is switched.

  When the motor 681 rotates in a certain direction, the motor 681 rotates to set the direction of the vertical axis of the second polarizer 68 immediately before switching the mode, and during the photoelectric conversion operation of the solid-state image sensor 62, the motor 681 The rotation may be stopped. Also, as in the first and third examples of mode switching timing, when mode switching is performed for each line or within one line, the polarization switching control unit 680 continues to rotate the motor 681 in a certain direction, The rotational speed of the motor 681 may be controlled based on the conveyance speed of the recording paper 10. At this time, for example, at the time of photoelectric conversion in the colorimetric mode, the transmission axis direction of the second polarizer 68 is arranged in a range intersecting with the polarization direction of the specularly reflected light at an angle smaller than 45 °, and the gloss measurement mode. During the photoelectric conversion, the rotation speed of the motor 681 is controlled so that the transmission axis direction of the second polarizer 68 is arranged in a range close to 90 ° with respect to the polarization direction of the regular reflection light.

<Second Embodiment>
An image forming apparatus according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 9 is a schematic diagram showing a configuration around the second polarizer 68 of the image inspection apparatus in the image forming apparatus of the present embodiment.

  As shown in FIG. 9, the image inspection apparatus 6 in the image forming apparatus of the present embodiment includes a slide mechanism 683 that slides the second polarizer 68 whose transmission axis is a fixed direction. The slide mechanism 683 slides the second polarizer 68 in a direction perpendicular to the main scanning direction of the solid-state image sensor 62 on a plane perpendicular to the optical path from the imaging lens 63 to the solid-state image sensor 62. Let The slide mechanism 683 includes a rack 684 that meshes with a gear 682 that is rotated by a motor 681, and performs a slide operation by the rotation of the motor 681. Further, the motor 681 is controlled by a PWM circuit in the polarization switching control unit 680 as in the image inspection apparatus 6 of the first embodiment.

  As described above, the image inspection apparatus 6 includes the configuration in which the second polarizer 68 is slid by the slide mechanism 683, so that the optical path from the imaging lens 63 to the solid-state image sensor 62 is connected to the second polarizer 68 in the colorimetric mode. In the gloss measurement mode, the second polarizer 68 is positioned on the optical path from the imaging lens 63 to the solid-state image sensor 62 (broken line position in FIG. 9). To place. Thereby, in the colorimetric mode, as shown in FIG. 3C, both the regular reflection light and the diffuse reflection light are transmitted in the state where the second polarizer 68 is not disposed in front of the solid-state image sensor 62. Is incident on. On the other hand, in the gloss measurement mode, the second polarizer 68 whose transmission axis direction is perpendicular to the polarization direction of the regular reflection light as shown in FIG. In particular, only diffusely reflected light is incident on the solid-state image sensor 62.

  At this time, the rotation of the motor 681 causes the second polarizer 68 to move between the solid line position and the broken line position in FIG. Therefore, after the second polarizer 68 is fixed at the solid line position, the solid-state image sensor 62 performs the photoelectric conversion operation in the colorimetric mode, and after the second polarizer 68 is fixed at the broken line position, the solid-state image sensor 62 performs a photoelectric conversion operation in the gloss measurement mode. In this embodiment, the slide mechanism 683 is configured to slide with the gear 682 rotated by the motor 681 and the rack 684. However, the present invention is not limited to such a configuration, and for example, configured by a belt rotated by the motor 681. Then, other configurations such as a configuration in which the second polarizer 68 is slid and a configuration in which the second polarizer 68 is slid by a small linear motor may be used.

  Further, in the present embodiment, the colorimetry mode and the gloss measurement mode are switched by sliding only the second polarizer 68 whose transmission axis direction is set in the direction in which the regularly reflected light is shielded by the slide mechanism 683. However, as shown in FIG. 10, the second polarizer 68 a that is adjacent to the second polarizer 68 and whose transmission axis direction is set in a direction that transmits only the specularly reflected light is supported by the slide mechanism 683. It does not matter. That is, the second polarizers 68 and 68 a are supported by the slide mechanism 683 in such an arrangement that the second polarizers 68 and 68 a are adjacent to each other in a direction perpendicular to the main scanning direction of the solid-state imaging device 62. Then, each of the second polarizers 68 and 68 a slides on a plane perpendicular to the optical path from the imaging lens 63 to the solid-state imaging device 62 by the slide mechanism 683, so that the solid-state imaging device 62 from the imaging lens 63. One of the second polarizers 68 and 68a is disposed on the optical path to the. Therefore, when the second polarizer 68 is disposed in front of the solid-state image sensor 62, the image inspection apparatus 6 operates in the colorimetric mode, and when the second polarizer 68a is disposed in front of the solid-state image sensor 62, The image inspection device 6 operates in the gloss measurement mode.

<Third Embodiment>
An image forming apparatus according to a third embodiment of the present invention will be described below with reference to the drawings. FIG. 11 is a schematic diagram showing a configuration around the second polarizer 68 of the image inspection apparatus in the image forming apparatus of the present embodiment.

  As shown in FIG. 10, the image inspection apparatus 6 in the image forming apparatus according to the present embodiment has a liquid crystal element 685 arranged on the surface of the second polarizer 68 on the imaging lens 63 side whose transmission axis is a fixed direction. It has a configuration. The liquid crystal element 685 is configured by laminating a transparent electrode layer, an alignment film, a liquid crystal layer, an alignment film, and a transparent electrode layer in this order on the surface of the second polarizer 68 on the imaging lens 63 side. Then, the polarization switching control unit 680 controls application of voltage to the two transparent electrode layers in the liquid crystal element 685. As a result, voltage application to the liquid crystal element 685 is controlled, and the arrangement of liquid crystal molecules in the liquid crystal layer is controlled, whereby the polarization direction of light passing through the liquid crystal element 685 is manipulated, and the colorimetric mode and glossiness are controlled. Switch between measurement modes.

  In this way, the liquid crystal element 685 provided in the image inspection apparatus 6 is arranged such that the liquid crystal molecules of the liquid crystal layer are rotated by 90 ° along the stacking direction by the two alignment films sandwiching the liquid crystal layer. The alignment direction of the alignment film on the imaging lens 63 side is the same as the polarization direction of the regular reflection light. Therefore, when no voltage is applied to the liquid crystal element 685, the specularly reflected light transmitted through the liquid crystal element 685 is guided to the second polarizer 68 with its polarization direction rotated by 90 °. On the other hand, when a voltage is applied to the liquid crystal element 685, the liquid crystal element 685 is aligned without rotation by the application of the voltage, so that each of the regular reflection light and the diffuse reflection light is rotated without rotating its polarization direction. Permeate up to 68.

  The second polarizer 68 has its transmission axis direction perpendicular to the polarization direction of the specularly reflected light as shown in FIG. 3D, and when there is no voltage applied to the liquid crystal element 685, the polarization direction thereof. The regular reflection light rotated by 90 ° is transmitted through the second polarizer 68. Accordingly, since only the regular reflection light is incident on the solid-state image sensor 62, the image inspection apparatus 6 operates in the color measurement mode. On the other hand, when a voltage is applied to the liquid crystal element 685, the polarization direction of each of the regular reflection light and diffuse reflection light passing through the liquid crystal element 685 does not change. Accordingly, the specularly reflected light is blocked by the second polarizer 68 and only the diffusely reflected light is incident on the solid-state imaging device 62, so that the image inspection apparatus 6 operates in the gloss measurement mode.

  In the above-described basic configuration and the first to third embodiments, the second polarizer 68 is disposed between the solid-state imaging device 62 and the imaging lens 63. What is necessary is just to be arrange | positioned on the optical path which regular reflection light advances. That is, the second polarizer 68 is connected to the optical path connecting the reading position P1 of the recording paper 10 and the reflecting mirror 65A, the optical path connecting the reflecting mirrors 65A and 65B, the optical path of the reflecting mirrors 65B and 65C, and the reflecting mirror 65C. It may be arranged on the optical path connecting the image lens 63 or the like. In the basic configuration and the first to third embodiments, the image forming apparatus according to the present invention has been described by taking an electrophotographic image forming apparatus as an example. However, the image inspection apparatus and the control apparatus described above are used. As long as it is provided, the image forming apparatus is not limited to the electrophotographic method, and may be an image forming apparatus including an image forming mechanism of another method such as an ink jet method.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image reading apparatus 3 Paper feed mechanism 4 Image forming apparatus 3 Fixing apparatus 6 Image inspection apparatus 7 Paper discharge mechanism 8 Control apparatus 61 Light source 62 Solid-state image sensor 63 Imaging lens 64 Glass plate 65A-65C Reflective mirror 66 Reference | standard Plate 67 First polarizer 68 Second polarizer 81 CPU
82 ROM
83 RAM
84 Image data generation unit 85 Shading correction value calculation unit 86 Mode selection unit 87 Input / output interface 88 Bus 610 Light emission control unit 620 Imaging control unit 621 Output amplifier 680 Polarization switching control unit

Claims (11)

A light source that irradiates light on an image formed on the recording paper, an optical system that configures an optical path through which the specularly reflected light from the light source passes on the recording paper, and light that is guided by the optical system is received. In an image inspection apparatus comprising:
A first polarizer that is disposed on an optical path from the light source to the recording paper, and that transmits light linearly polarized in a predetermined polarization direction of the irradiation light from the light source toward the recording paper;
A second polarizer that is provided as part of the optical system and regulates the polarization direction of light received by the solid-state imaging device;
A polarization switching control unit that controls whether or not the optical system transmits light from the optical system to the solid-state image sensor with specularly reflected light from the recording paper;
With
When the transmission of the regular reflection light is prohibited by the polarization switching control unit, the regular reflection light is blocked by the second polarizer, and the solid-state imaging device receives diffuse reflection light other than the regular reflection light. While operating in a colorimetric mode that outputs color image data,
When the transmission of the regular reflection light is permitted by the polarization switching control unit, the solid-state imaging device receives the regular reflection light without the regular reflection light being blocked by the second polarizer, and gloss Operates in gloss measurement mode that outputs image data,
By alternately operating the colorimetry mode and the gloss measurement mode at predetermined time intervals while passing a sheet of recording paper, the color image data and the gloss image data of the image on the recording paper are simultaneously obtained. An image inspection apparatus that outputs the image.   The image inspection apparatus according to claim 1, wherein the color measurement mode and the gloss measurement mode are switched for each predetermined pixel of one pixel or more along the sub-scanning direction of the recording paper.   The image inspection apparatus according to claim 1, wherein the colorimetry mode and the gloss measurement mode are switched within one pixel along the sub-scanning direction of the recording paper. A mechanism that is controlled by the polarization switching control unit and rotates the second polarizer in a plane perpendicular to an optical path connecting the optical system and the solid-state imaging device;
4. The colorimetry mode and the gloss measurement mode are switched by rotating the second polarizer by the mechanism and switching the transmission axis direction of the second polarizer. The image inspection apparatus according to any one of claims. A mechanism that is controlled by the polarization switching control unit and that slides the second polarizer in a plane perpendicular to an optical path connecting the optical system and the solid-state imaging device;
2. The colorimetry mode and the gloss measurement mode are switched by the mechanism by sliding the second polarizer in a direction perpendicular to the main scanning direction of the solid-state imaging device. Image inspection apparatus as described in any one of -3. A liquid crystal element controlled by the polarization switching control unit and disposed on a light incident side of the second polarizer;
The colorimetry mode and the gloss measurement mode are switched by controlling whether or not the polarization direction of light transmitted through the liquid crystal element is rotated depending on whether or not a voltage is applied to the liquid crystal element. The image inspection apparatus as described in any one of 1-3.   The image inspection according to claim 1, wherein a transmission axis direction of the second polarizer in the color measurement mode is perpendicular to a polarization direction of the regular reflection light. apparatus.   7. The transmission axis direction of the second polarizer in the gloss measurement mode intersects with the polarization direction of the regular reflection light at an angle smaller than 90 °. Image inspection equipment.   The image inspection apparatus according to claim 8, wherein a transmission axis direction of the second polarizer in the gloss measurement mode is the same direction as a polarization direction of the regular reflection light.   10. The direction of light emitted from the light source to the recording paper through the first polarizer is 45 [deg.] Or less with respect to the normal line of the image inspection surface of the recording paper. The image inspection apparatus according to any one of the above.   An image forming apparatus comprising the image inspection apparatus according to claim 1.

Images