JP2023125597A - Image reading device and image forming apparatus - Google Patents

Abstract

To provide an image reading device that can accelerate an operation to read a reference surface unit.SOLUTION: An image reading device 50 reads an object to be conveyed with an image sensor 51a, and the device has: a reference surface unit 61c that is provided at a portion separate from an image reading unit 52 for the object; and optical path switching means 60 that switches an optical path to the image sensor between the image reading unit and the reference surface unit through change of attitude at a fixed position. The optical path switching means 60 is a polyhedral columnar body including a reflecting surface and switches the optical path through change of attitude by rotation.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image reading device and an image forming device.

2. Description of the Related Art Conventionally, image reading devices that use an image sensor to read a conveyed object are known.

Patent Document 1 and Patent Document 2 disclose such an image reading device in which a white reference portion (reference surface portion) for shading correction is located at a reading position located in an image reading portion of an original (object to be conveyed). A device is described that is movable between a retracted position and a retracted position from the image reading unit. When the white reference section is not being read, the white reference section can be moved to a retracted position to suppress staining of the white reference section.

However, when reading the reference surface section by positioning the reference surface section at the reading position only during the period when objects that are continuously conveyed at predetermined intervals face the image reading section (so-called paper interval), the reference surface section It was difficult to speed up the reading operation. This is due to restrictions on the moving speed of the reference plane between the retracted position and the reading position.

In order to solve the above-mentioned problems, the present invention provides an image reading device that reads a conveyed object with an image sensor, a reference surface part provided at a location different from the image reading section of the object, and a posture at a fixed position. The present invention is characterized in that it includes an optical path switching means for switching an optical path to the image sensor between the image reading section and the reference surface section.

According to the present invention, it is possible to speed up the reading operation of the reference surface portion.

An overall configuration diagram of the printer. FIG. 1 is an explanatory diagram of the basic configuration of an image reading device. FIG. 1 is an explanatory diagram of an image reading device according to the present embodiment. FIG. 3 is an explanatory diagram of the operation of the image reading device. FIG. 4 is an explanatory diagram of a configuration example of a facing unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a printer that is a color-compatible electrophotographic image forming apparatus will be described with reference to the drawings. First, an outline of the printer 300 of this embodiment will be explained. FIG. 1 is an overall configuration diagram of a printer 300. The printer 300 includes an operation/display section 200 at the top of the device body 100. The main body 100 of the printer 300 includes an image forming section as a tandem image forming means including four process units 1Y, C, M, and Bk.

The four process units 1Y, C, M, and Bk have the same configuration except that they contain toners of different colors: yellow (Y), cyan (C), magenta (M), and black (Bk). Each process unit 1 forms an image using an electrophotographic method, and includes a photoreceptor 2, a charging device 3, a developing device 4, a cleaning blade 5, and the like. Other methods such as an inkjet method may be used instead of the electrophotographic method.

The transfer device 7 provided below each process unit 1 has an intermediate transfer belt 10 as an intermediate transfer body. The intermediate transfer belt 10 is stretched around a first tension roller 21 , a second tension roller 22 , and a third tension roller 23 , and is pressed inward by a tension roller 24 .

Four primary transfer rollers 11 are arranged at positions facing the four photoreceptors 2 with an intermediate transfer belt 10 interposed therebetween. Each primary transfer roller 11 is connected to a power source. A secondary transfer roller 12 serving as secondary transfer means is provided at a position facing the third tension roller 23 that stretches the intermediate transfer belt 10 . This secondary transfer roller 12 forms a secondary transfer nip at a location where it contacts the intermediate transfer belt 10 . The secondary transfer roller 12 is connected to a power source and can be supplied with a secondary transfer bias. Note that the secondary transfer means is not limited to a roller, but may be a belt.

At the bottom of the apparatus main body 100, a plurality of paper feed cassettes 13 containing recording materials P such as sheets of paper and OHP are arranged. The paper feed cassette 13 is provided with a paper feed roller 14 that feeds out the stored recording material P. A paper discharge tray 20 is provided on the outer surface of the apparatus main body 100 on the left side in the figure.

The apparatus main body 100 includes a conveyance path 25 for conveying the recording material P from the paper feed cassette 13 to the paper discharge tray 20 through the secondary transfer nip. In this conveyance path 25, a registration roller pair 15 is provided upstream of the position of the secondary transfer roller 12 in the paper conveyance direction. Furthermore, a fixing device 8 , a cooling device 9 , an image reading device 50 , and a pair of ejection rollers 16 are sequentially arranged downstream of the position of the secondary transfer roller 12 in the paper conveyance direction.

The fixing device 8 includes, for example, a fixing roller 17 as a fixing member that has a heater inside, and a pressure roller 18 as a pressure member that presses the fixing roller 17. A fixing nip is formed where the fixing roller 17 and the pressure roller 18 come into contact.

Further, a switching claw 26, which will be described later, is provided between the image reading device 50 and the discharge roller pair 16. This switching pawl 26 rotates when double-sided printing in which images are formed on both sides of the recording material P is selected in the print mode as an image forming mode, and the switching pawl 26 rotates when double-sided printing in which images are formed on both sides of the recording material P is selected. The recording material P is guided to a reversing path 27 provided between the paper feed cassette 13 and the paper feed cassette 13. The recording material P guided to the reversing path 27 is switched back within the reversing path 27 to have its front and back directions reversed, and enters the conveyance path 25 upstream of the registration roller pair 15 in order to form an image on the back surface.

The cooling device 9 has an endless front belt 97a and an endless back belt 97b. A front side cooling plate 91a is disposed on the inner circumferential side of the spreading surface of the front side belt 97a that sandwiches the recording material P, and a back side cooling plate 91a is arranged on the inner circumferential side of the spreading surface of the back side belt 97b that sandwiches the recording material P. A plate 91b is arranged.

The cooling device 9 also includes a pump 92, a tank 93, a radiator 94, a cooling fan 95, piping 96, and the like. The cooling device 9 circulates cooling liquid between a front side cooling plate 91a, a back side cooling plate 91b, a radiator 94, a tank 93, and a pump 92. Arrow A indicates the flow of liquid in the cooling liquid circulation path. A cooling fan 95 and a radiator 94 are located within the duct 28. The duct 28 includes an intake port 28a provided below and an exhaust port 28b provided above.

The basic operation of printer 300 is as follows. A case where single-sided printing is selected as the print mode will be described. When image data is received from an external device such as a personal computer and an image forming operation is started, the image data from the external device is transferred to each charged photoreceptor from the exposure device 6 based on the image information processed by the image processing section. 2 is irradiated with laser light, and an electrostatic latent image is formed on the surface of each photoreceptor 2. The image information exposed on each photoreceptor 2 is monochrome image information obtained by separating a desired full-color image into yellow, cyan, magenta, and black color information. The electrostatic latent image formed on the photoreceptor 2 is converted into a toner image by each developing device 4 . These toner images are sequentially transferred onto the intermediate transfer belt 10 in a superimposed manner. The toner images carried on the intermediate transfer belt 10 are secondarily transferred all at once onto the recording material P carried out from the paper feed cassette 13 .

The recording material P on which the toner image has been secondarily transferred is conveyed to the fixing device 8, where the recording material P is pressed and heated by the fixing roller 17 and the pressure roller 18, and the toner image is fixed onto the recording material P. . After being cooled by the cooling device 9, the recording material P is discharged onto a paper discharge tray 20 by a pair of discharge rollers 16.

FIG. 2 is an explanatory diagram of the basic configuration of the image reading device 50. FIG. 2(a) is a schematic diagram showing a schematic configuration of the image reading device 50, and FIG. 2(b) is a partially enlarged diagram. The image reading device 50 includes a reading device 51, an illumination unit 52, and a facing unit 53, and reads an image on the recording material P that is being conveyed. In the illustrated example, one image reading device 50 can read the entire width of the recording material P perpendicular to the paper surface, but a plurality of image reading devices 50 are arranged at different positions in the width direction, and each image reading device The output image formed on the paper may be obtained (read) by performing image processing such as joining (synthesizing) the read images read in the above steps.

The reading device 51 includes an image sensor 51a, a lens 51b, a third mirror 51c, a second mirror 51d, a first mirror 51e, etc., and reads the recording material P illuminated by the illumination unit 52 or the image on the recording material P. . The image sensor 51a is an in-line sensor. The read data can be used for various corrections described later. In this embodiment, as will be described later, a six-sided polygon mirror 60, which is a polygonal columnar body, is used as the optical path switching means in place of the illustrated first mirror 51e (see FIG. 3).

As shown in FIG. 2(b), the illumination unit 52 includes two illumination light sources 52a and 52b and a contact glass 52c which is a transparent member. As shown in FIG. 2A, the illumination unit 52 directly above the conveyance path (paper conveyance path) of the recording materials P1 and P2 illuminates the recording materials P1 and P2 being conveyed, and diffused light is reflected on the recording materials. The image is read by passing the light through the reading optical axis A21 and focusing it on the image sensor 51a.

The image reading device 50 includes a facing unit 53 at a location facing the contact glass 52c across the conveyance path of the recording material P. The opposing unit 53 includes four opposing rollers 54 as opposing members and a rotating support body 55 as a rotating member that supports these opposing rollers. These four opposing rollers 54 have different diameters and colors of their circumferential surfaces. A specific example will be described later.

The rotating support body 55 rotatably supports each of the four rollers, and by rotating, any one of the rollers can be positioned at the image reading position. The facing unit 53 selects one of the corresponding ones according to information on the recording material P (information for specifying paper thickness, paper color, etc.) and the operation mode of the image forming system (difference in conveyance speed, etc.). The opposing roller 54 is positioned at the image reading position. In paper position detection, in order to detect paper edges, it is preferable that the background has a color different from the color of the paper. From this point of view, the opposing member is sometimes referred to as a background member or a backing member.

Conventionally, in the illumination portion of the illumination unit 52 of the image reading device 50, the amount of light decreases over time, causing the reading level to fluctuate. Furthermore, variations in the main force characteristics in the longitudinal direction of the image sensor 51a of the reading device 51 lead to variations in read data. In order to prevent these problems, shading correction is performed by periodically reading the reference white board and correcting the reading level. For example, when the circumferential surface of the opposing roller at the reading position is black, when reading the reference white plate for periodic shading correction, place the reference white plate between the sheets of paper passing on the reading optical axis A21. Insertion is done instantaneously.

However, the conventional technology has the following problems. As in Patent Document 1, when performing shading correction, a mechanism in which a D-cut roller with a white plate attached thereto is rotated to move the white plate to the document surface and read the document uses the black backing portion of the D-cut roller. In addition to detecting white paper, it is possible to perform reading for shading correction between papers by positioning it on the white plate document surface depending on the rotational phase. As shown in FIG. 36 of the same document, the time required for shading is shortened by providing a plurality of paper passing surfaces and shading surfaces on the circumference. However, in this document, for example, the three paper passing surfaces 45b shown in FIG. 36 must all have the same shape, otherwise it will be necessary to rotate forward and reverse during shading. Normal rotation and reverse rotation are different from simply repeating rotation and stopping in one direction, and there is a restriction that it takes extra time. is difficult. If paper detection is not performed, the white plate can be kept on the document surface during continuous paper feeding, but the white plate will become dirty. In order to avoid such restrictions, there is a layout restriction in that the three paper passing surfaces 45b must all have the same shape.

In this embodiment, in order to solve such a problem, the image sensor is equipped with a reference surface section provided at a location other than the image reading section of the recording material P (object to be conveyed) and by changing the posture at a fixed position. and an optical path switching means for switching the optical path between the image reading section and the reference surface section. FIG. 3 is an explanatory diagram of the image reading device according to this embodiment. 3(a) shows a state in which the reading optical axis A21 faces the image reading section of the illumination unit 52, and FIG. 3(b) shows a state in which the reading optical axis A22 faces the reference plane part.

The basic configuration of the image reading device 50 shown in FIG. 2 is modified as follows. That is, instead of the first mirror 51e, a six-sided polygon mirror 60, which is a polygonal columnar body, is used as the optical path switching means. In addition, a reference plane unit 61 was provided at a location different from the recording material conveyance path. The reference plane unit 61 includes a white reference plate 61d as a reference plane part, illumination light sources 61a and 61b as illumination means for irradiating light onto the white reference plate 61d, and a contact glass 61c. The illustrated example has a structure in which a white reference plate 61d is closely fixed to a contact glass 61c of a unit having the same structure as the illumination unit 52. Although the contact glass 61c may be omitted, it is easier to set the optical path length to the image sensor 51a, which will be described later, if the contact glass 61c has a common structure with the illumination unit 52.

In the state shown in FIG. 3A, the optical path length from the surface of the object to be read in the image reading section of the illumination unit 52 to the image sensor 51a through the reflective surface 60 that the reading optical axis A21 hits is the following optical path length. 60 and a reference plane unit 61 are provided so that they are equal. In other words, the optical path length is equal to the length of the optical path from the irradiated surface of the white reference plate 61d of the reference plane unit 61 to the image sensor 51a via the reflective surface of the polygon mirror 60 on which the reading optical axis A22 hits in the state shown in FIG. 3(b). Provided as follows. According to this, it is possible to read the white reference plate 61d under the same conditions as when reading the recording material and obtain data for shading correction.

For example, the optical path lengths to the image sensor 51a are equal between the reflective surface of the polygon mirror 60 that the reading optical axis A21 hits and the reflective surface of the polygon mirror 60 that the reading optical axis A22 hits, and the object to be read by the image reading unit The optical path length from the surface of the object to the reflective surface of the polygon mirror 60 that is hit by the reading optical axis A21, and from the irradiated surface of the white reference plate 61d of the reference plane unit 61 to the reflective surface of the polygon mirror 60 that is hit by the reading optical axis A22. so that the optical path length of

In addition to making the optical path lengths at each location equal as described above, it is also preferable to make the optical path lengths from the illumination light source to the image sensor 51a equal. It is also possible to make a difference in the optical path length at each of the above locations, and to cancel out the amount of change in the amount of light at the image sensor 51a due to this difference by the difference in the amount of light between the illumination light sources. For example, if the white reference plate 61d of the reference plane unit 61 and the illumination light sources 61a and 61b are optically closer to the image sensor 51a than the illumination unit 52, the amount of light that reaches the image sensor 51a when reading the white reference plate 61d The amount of light will be greater than the amount of light used when reading the original, resulting in poor shading. In order to prevent this, when the plurality of reference white plates and the illumination unit are optically brought closer to the image sensor 51a, only the illumination light sources 61a and 61b are slightly darkened to save space. In the illustrated example, the illumination light source 61 is provided, but if necessary, the light from the illumination light source of the illumination unit 52 may also be used as the light from the illumination light source of the illumination unit 52 by using an optical path switching means for light from the illumination light source.

To switch from the reading optical axis A21 in FIG. 3(a) to the reading optical axis A22 in FIG. 3(b), rotate the polygon mirror 60 counterclockwise in the figure as shown by arrow A3 in FIG. 3(b). . The rotation angle is half of the angle θ between the reading optical axes shown in FIG. 3(b). While maintaining the rotational position shown in FIG. 3(b) (while stopping rotation), the white reference plate 61d is read. Instead of reading the white reference plate 61d in a stopped state as described above, a wider range of the white reference plate 61d may be read while rotating the polygon mirror 60. The former is suitable for adjusting the light amount of the light source, and the latter is suitable for adjusting the output deviation in the longitudinal direction of the image sensor 51a. It is preferable to switch the reading method as necessary. The switching of the reading method of these white reference plates is similar to the switching of the reading method of the conventional white reference plate.

FIG. 4 shows that after shading, the reading optical axis A22 hits the polygon mirror 60 and stops at one surface on the upstream side in the opposite rotational direction (see FIG. 3(b)), and the reading optical axis A21 indicates a state in which the recording material conveyance path is illuminated. Since the polygon mirror 60 is a hexahedron, it has a phase difference of 60 degrees with respect to the reflecting surface used in the state shown in FIG. 3(a).

In the examples shown in FIGS. 3 and 4, the optical path switching means is a hexagonal prism mirror, and the phase moved by one degree of paper shading is 60 degrees. Therefore, as in the configuration of the D-cut roller in Patent Document 1, it is possible to perform inter-sheet shading while rotating in one direction, thereby making it possible to shorten the inter-sheet time. Unlike the reading device of Patent Document 2, there is no need to separate the illumination of the reading surface of the recording material, so the time can be shortened accordingly. Further, by installing the illumination unit 61 separately from the recording material reading surface illumination unit 52, there are no layout restrictions on the illumination of the recording material reading surface. Therefore, it is possible to obtain a degree of freedom such as using the opposing rollers 54 of the opposing unit 53 in different colors and diameters.

FIG. 5 is an explanatory diagram of a configuration example of the opposing unit 53. The opposing unit 53 includes four opposing rollers 54a, 54b, 54c, and 54d, three reference surface members 56a, 56b, and 56c as moving reference surface portions, and a guide member 57. The four opposing rollers 54a, 54b, 54c, and 54d do not interfere with the conveyance of the recording material P when the recording material P is conveyed so that the image can be read at a position with an appropriate focal length of the image reading device 50. It is preferable to rotate it as follows. Alternatively, the recording material may be driven to rotate. The four opposing rollers 54a, 54b, 54c, and 54d are rotatably held by the rotating support 55, and the three reference surface members 56a, 56b, and 56c and the guide member 57 are fixed to the rotating support 55. It is maintained as such.

By rotating the rotation support body 55 of the opposing unit 53, the four opposing rollers 54a, 54b, 54c, and 54d, the three reference surface members 56a, 56b, and 56c, and the guide member 57 rotate integrally. Thereby, the facing unit 53 selects each of the four facing rollers 54a, 54b, 54c, 54d, the reference surface members 56a, 56b, 56c, and the guide member 57 to a predetermined reading position where the image reading device 50 reads the image. It is possible to switch and place them.

In order to suppress the flapping of the recording material P and to read the image at an appropriate focal length that matches the focal length of the optical system of the image reading device 50, the distance from the contact glass 52c to the position of the appropriate focal length (reading position) is adjusted. By making it shorter, the gap through which the recording material P passes is narrowed. Therefore, at the time of image reading to read the image of the recording material P, at least one of the four opposing rollers 54a, 54b, 54c, and 54d is placed at the reading position so that the recording material P is reliably conveyed through the narrow gap. It is preferable to drive the rollers in rotation.

In the example shown in FIG. 5, the appropriate focal length of the image reading device 50 is set to the surface of the recording material P when it comes into contact with the opposing roller 54c (see the outer dot-dashed line circle), and the contact glass 52c and the opposing roller 54c The gap between the two is made as small as possible. When reading an image while conveying the recording material P through this gap, the opposing roller 54c is rotationally driven so that its surface moves in the same direction as the conveyance direction of the recording material P. As a result, the gap between the contact glass 52c and the opposing roller 54c is reduced to suppress flapping of the recording material P due to conveyance, while the opposing roller 54c rotates in contact with the recording material P being conveyed, and the recording material P paper can be transported reliably without causing a paper jam.

On the other hand, during an interval between conveyance of the recording material P, such as before an image reading operation, the rotary support body 55 is rotated to place one of the three reference surface members 56a, 56b, and 56c at the reading position. Each correction operation is performed by the image reading device 50 reading the reference surface member. At this time, the positions of the outer surfaces of the reference plane members 56a, 56b, and 56c were arranged so as to coincide with the position of the appropriate focal length (reading position) (see the dashed-dotted circle indicated by the outer reference numeral 55a). During the period in which the correction operation is performed, the recording material P is not conveyed and the recording material P is not allowed to enter the reading position.

Further, the reference plane members 56a, 56b, and 56c are configured to switch the rotation so that even if a stop angle error occurs in the rotation switching mechanism that rotates the rotation support 55, the position and inclination of the reference plane do not change. It has a curved shape centered around the rotation center of the mechanism.

Note that in a non-image reading operation in which the recording material P is simply conveyed without reading an image of the recording material P, it is not necessary to convey the recording material P while maintaining it at a proper focal position. For this reason, the recording material P is conveyed with the guide member 57 functioning as a guide portion disposed on the opposite side of the reading position so that the clearance is such that it can be conveyed even without the conveying force of the rollers at the reading position.

For example, the reference surface member 56a is a reference surface member having a white uniform white reference surface as a reference surface. When performing shading correction of the image reading device 50, this reference surface member 56a is placed at the reading position. The reference surface member 56a may be a reference surface member having a black reference surface with a uniform black surface. When the image reading device 50 reads an image of the recording material P, the reference surface member 56a having the black reference surface may be placed at the reading position.

For example, the reference surface member 56b is a reference surface member having a reference color patch as a reference surface. When correcting the color output of the image reading device 50, the reference plane member 56b is placed at the reading position.

For example, the reference surface member 56c is a reference surface member having line images at known intervals as a reference surface. When correcting the magnification, registration, etc. of the image reading device 50, the reference plane member 56c is placed at the reading position.

As described above, the read data of the white surface as the moving reference plane portion can be used for shading correction, and the read data of the surfaces of other colors as the moving reference plane portion can be used for color correction. Furthermore, the four opposing rollers 54a, 54b, 54c, and 54d can be used to detect the position or orientation of the recording material P or the image, or to detect the image itself.

A rotary support is required so that the reference surface members 56a, 56b, and 56c of the opposing unit 53 are positioned at the image reading position only between sheets during continuous sheet feeding, and take the retracted position while the recording material passes through the image reading position. If the paper is moved while being rotated in forward and reverse directions according to the rotation speed, the continuous paper passing speed must be slowed down due to restrictions on the speed of forward and reverse rotation. Therefore, the reference surface members 56a, 56b, and 56c are positioned at the reading positions to obtain correction data not during continuous paper passing, but at the following timing. That is, after the printer is powered on, before the first recording material of a print job such as continuous paper feeding reaches the reading position, after the print job ends, or at any other timing other than during continuous paper feeding. During continuous paper feeding, in a mode in which the reading position reads the position of the recording material P and the image on the recording material P, and also reads the white surface for shading correction, an image reading section is added between the sheets. At this timing, the reading optical axis A22 is directed toward the reference surface unit 61 as shown in FIG. 3(b).

Note that the reference surface unit 61 uses a facing roller to read the paper or the image on the paper during the time period when the paper faces the image reading unit before and after reading the reference surface portion between sheets during continuous paper feeding. In this mode, you can effectively utilize the high-speed switching of optical paths due to polygon rotation. Unlike this mode, the reference surface unit 61 may read the reference surface portion during continuous paper feeding in a mode in which paper or an image on the paper is read using opposing rollers. In this case, after first performing a polygon rotation to direct the reading optical axis A22 toward the reference surface unit 61 (a low-speed rotation that matches the timing of the arrival of the first paper is sufficient), the distance between the reference surface unit 61 and the image reading section is No optical path switching required.

As described above, in this embodiment, the image reading device reads the paper that has passed the fixing process, but it may also read the paper that is transported at another location within the image forming apparatus. It can also be applied to devices that read originals. It can also be applied to a single scanner that reads originals. The present invention can also be applied to reading devices other than image forming devices such as banknote reading. Although the facing unit 53 is also provided with a white reference part, the present invention can also be applied to a system in which the facing unit 53 is not provided with a white reference part. The reference surface portion of the reference surface unit 61 is not limited to white, but can also be applied to reference surface portions of other colors for color correction. Although a hexagonal prism-shaped rotating body is used, other shapes having two or more surfaces, for example, a triangular prism-shaped rotating body may be used. It is also possible to use a device having only one surface or two or more surfaces and having a shape other than rotationally symmetrical, and whose posture can be changed by rotation or rocking. In either case, it is preferable that the surface changes its attitude by rotating around the center of rotation.

1: Process unit 2: Photoreceptor 3: Charging device 4: Developing device 5: Cleaning blade 6: Exposure device 7: Transfer device 8: Fixing device 9: Cooling device 10: Intermediate transfer belt 11: Primary transfer roller 12: 2 Next transfer roller 13: Paper feed cassette 14: Paper feed roller 15: Registration roller pair 16: Ejection roller pair 17: Fixing roller 18: Pressure roller 20: Paper ejection tray 21: First tension roller 22: Second tension roller Roller 23: Third tension roller 24: Tension roller 25: Conveyance path 26: Switching claw 27: Reversing path 28: Duct 28a: Intake port 28b: Exhaust port 45b: Paper passing surface 50: Image reading device 51: Reading device 51a: Image sensor 51b: Lens 51c: Third mirror 51d: Second mirror 51e: First mirror 52: Illumination unit 52a: Illumination light source 52b: Illumination light source 52c: Contact glass 53: Opposing unit 54: Opposing roller 55: Rotating support body 56a : Reference surface member 56b : Reference surface member 56c : Reference surface member 57 : Guide member 60 : Polygon mirror 61 : Reference surface unit 61a : Illumination light source 61b : Illumination light source 61c : Contact glass 61d : White reference plate 91a : Front side cooling plate 91b : Back side cooling plate 92 : Pump 93 : Tank 94 : Radiator 95 : Cooling fan 96 : Piping 97a : Front side belt 97b : Back side belt 100 : Device body 200 : Display section 300 : Printer A21 : Reading optical axis A22 : Reading optical axis P :Recording material P1 :Recording material P2 :Recording material

Patent No. 550577 Japanese Patent Application Publication No. 2005-328156

Claims (10)

In an image reading device that uses an image sensor to read a conveyed object,
a reference surface section provided at a location different from the image reading section of the object;
An image reading device comprising: an optical path switching device that switches an optical path to the image sensor between the image reading section and the reference surface section by changing the posture at a fixed position. The image reading device according to claim 1,
The image reading device is characterized in that the optical path switching means is a polygonal columnar body having a reflective surface, and the optical path is switched by changing the orientation by rotation. The image reading device according to claim 1 or 2,
An image reading device characterized in that an illumination means for irradiating light onto the reference plane section is provided separately from an illumination means for irradiating light onto an object in the image reading section. The image reading device according to claim 3,
The image reading device is characterized in that the object surface irradiated with light in the image reading section and the reference surface section have the same optical path length to the image sensor. The image reading device according to claim 3,
The object surface irradiated with light in the image reading section and the reference surface section have different optical path lengths up to the image sensor, and the illumination means of the image reading section and the illumination means of the reference surface section have different optical path lengths. An image reading device characterized in that the difference is canceled out so that illuminances detected by the image sensor on the surface of the object and on the reference surface portion are equal to each other. The image reading device according to any one of claims 1 to 5,
An image reading device comprising: a movable reference surface portion for shading correction that is movable between a reading position located in the image reading unit and a retracted position retracted from the image reading unit. The image reading device according to claim 6,
The image reading device is characterized in that the moving reference surface portion at the reading position and the reference surface portion have the same optical path length to the image sensor. The image reading device according to any one of claims 1 to 7,
an opposing member that faces the object from the opposite side of the image sensor across the conveyance path and is movable between a reading position located in the image reading unit and a retracted position evacuated from the image reading unit; An image reading device comprising: In the image reading device according to claim 8, which cites claim 6 or 7,
An image reading device characterized in that the moving reference surface portion and the opposing member are provided on a rotating member. an image forming unit that forms an image on an object;
an image reading unit that reads the object;
An image forming apparatus including a transport section that transports the object,
An image forming apparatus characterized in that the image reading device according to any one of claims 1 to 9 is used as the image reading section.

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