JP2021060372A - Optical sensor device and image forming apparatus - Google Patents

Abstract

To accurately detect the characteristics of a recording medium without being affected by the distribution of surface characteristics of the recording medium.SOLUTION: An optical sensor device 60 comprises: a light source 62; an optical system 63 that irradiates a surface of a recording medium in an irradiation area with light from the light source 62 at a predetermined angle of incidence; a first light receiving unit 641 that detects the quantity of regularly reflected light that is regularly reflected on the surface of the recording medium in the irradiation area; and at least one second light receiving unit 642 that detects the quantity of diffusely reflected light that is diffusely reflected on the surface of the recording medium in the irradiation area at at least one angle of reflection. The irradiation diameter of the light radiated from the light source in the irradiation area is set to an irradiation diameter at which the influence of nonuniformity of the fiber orientation of the recording medium is reduced.SELECTED DRAWING: Figure 7

Description

The present invention relates to an optical sensor device and an image forming device.

In recent years, in the color printing industry, image forming devices such as electrophotographic printers have been widely used. In the field of PP (production printing) corresponding to the color printing industry, adaptation to various types of paper is required as compared with the case of being used in the office. Then, in order to perform high-quality printing on these various types of paper, the paper characteristics stored in the paper feed tray are set for a plurality of items, and the image is printed under the image forming conditions according to the set items. There is a forming device.

In order to make such various paper settings, there is an image forming apparatus including a sensor that automatically detects the characteristics of the paper used for printing. For example, in Patent Document 1, the surface of a recording medium is irradiated with light from a beam at an incident angle of 70 ° to 88 °, and the intensity of the specularly reflected light received by the light receiving portion determines the intensity of the specularly reflected light of the recording medium. An image forming apparatus in which an optical sensor for calculating smoothness is arranged is disclosed. Further, in Patent Document 1, as a modification, a light receiving portion for receiving diffuse reflected light is further arranged, and the intensity of the received specular reflected light and the intensity of the diffuse reflected light are used to smooth from a predetermined conversion formula. A technique for calculating the degree is disclosed.

Japanese Unexamined Patent Publication No. 2012-194445 (paragraphs 0040 to 0041, 0092, FIG. 16)

However, in Patent Document 1, the irradiation light is emitted from a beam, and the beam has a small diameter and is narrowed down to about Φ1 mm. Depending on the type of paper, the size and length of the pulp fibers of the recording medium are not uniform, and the surface texture distribution varies greatly depending on the position (surface waviness). Therefore, when a beam having a small diameter as in Patent Document 1 is irradiated, the light receiving intensity varies greatly depending on the irradiation position, and the accuracy of determining the smoothness of the paper may decrease.

The present invention has been made in view of the above circumstances, and provides an optical sensor device capable of accurately detecting the characteristics of a recording medium without being affected by the surface distribution of the recording medium, and an image forming device including the same. The purpose is to do.

The above object of the present invention is achieved by the following means.

(1) Light source and
An optical system that irradiates the surface of a recording medium in the irradiation region with light from the light source at a predetermined angle of incidence.
A first light receiving unit that detects the amount of specularly reflected light that is specularly reflected on the surface of the recording medium in the irradiation region, and
A second light receiving portion for detecting the amount of diffusely reflected light diffusely reflected at at least one reflection angle on the surface of the recording medium in the irradiation region is provided.
An optical sensor device in which the irradiation diameter of light emitted from the light source in the irradiation region is set to an irradiation diameter at which the influence of non-uniformity of fiber orientation of the recording medium is reduced.

(2) The optical sensor device according to (1) above, wherein the irradiation diameter in the irradiation region is 6 mm or more.

(3) The optical sensor device according to (1) or (2) above, wherein the optical system includes a collimating lens.

(4) The optical sensor device according to (3) above, wherein the light source is arranged on the optical axis at a distance shorter than the focal length of the collimating lens with respect to the collimating lens.

(5) The optical sensor device according to any one of (1) to (4) above, wherein the emission wavelength of the light source is 445 nm or more and 500 nm or less.

(6) The first and second light receiving units are each provided with a slit provided in the light receiving path and a photodiode that receives incident light that has passed through the slit.
The optical sensor device according to any one of (1) to (5) above, wherein the slit has an inclined surface that is inclined so that the distance from the optical axis increases toward the incident side.

(7) A transport unit that transports the recording medium to a transport path provided with an irradiation region, and a transport unit.
The optical sensor device according to any one of (1) to (6) above, and
At least the detection results of the amount of specularly reflected light and diffusely reflected light from the surface of the recording medium conveyed to the irradiation region, which are detected by the first and second light receiving portions of the optical sensor device, are used at least. An image forming apparatus including a control unit for determining a paper type of the recording medium.

(8) The transport path includes an upper guide and a lower guide, and the irradiation region is an inner region of an opening provided in the upper guide.
Further, a shutter for opening and closing the opening is provided.
When the paper type of the recording medium is not determined, the opening is closed by the shutter.
The paper type of the recording medium is determined by opening the opening with the shutter and using the detection result of the optical sensor device to determine the paper type of the recording medium. Image forming device.

(9) The image forming apparatus according to (8) above, wherein the shutter is a flat plate member, and a calibration member is attached to one surface of the plate member.

(10) The image forming apparatus according to any one of (7) to (9) above, wherein the control unit determines the paper type by using a learned model for determining the paper type obtained by machine learning.

According to the optical sensor device according to the present invention, a light source, an optical system for irradiating the surface of a recording medium in an irradiation region with light from the light source at a predetermined incident angle, and regular reflection on the surface of the recording medium in the irradiation region. A first light receiving unit that detects the amount of positively reflected light, and at least one second light receiving unit that detects the amount of diffusely reflected light that is diffusely reflected at at least one reflection angle on the surface of the recording medium in the irradiation region. The irradiation diameter of the light source irradiated by the optical system in the irradiation region is set to an irradiation diameter that is less affected by the non-uniformity of the fiber orientation of the recording medium. By doing so, it is possible to provide an optical sensor device capable of accurately detecting the characteristics of the recording medium without being affected by the surface distribution of the recording medium, and an image forming device including the optical sensor device.

It is a figure which shows the schematic structure of the image formation system which includes the image formation apparatus which concerns on this embodiment. It is a side view which shows the structure of the media sensor arranged in the transport path. It is a perspective view which shows the structure of the basis weight sensor and the surface sensor. It is sectional drawing of the surface sensor. It is a perspective view which shows the internal structure of the surface sensor. It is sectional drawing of the surface sensor which shows the state which the shutter is open. It is a schematic diagram which shows the arrangement position of a light emitting part and a light receiving part. It is sectional drawing which shows the incident angle of the irradiation light and the arrangement angle of the light receiving part. It is a schematic diagram which shows the state of the pulp fiber on the paper surface. It is a schematic diagram which shows the fluctuation state of the microscopic fiber orientation angle of a paper. It is a schematic diagram which shows the surface distribution of paper and the diffusion state of irradiation light. It is a schematic diagram which shows the irradiation diameter of the irradiation light and the arrangement position of the light emitting part (light source). It is a graph which shows the variation of the detected light amount by the difference of the irradiation diameter when a plurality of points of a paper surface are measured. It is a graph which shows the transition of the detection accuracy when an error is added to the input data. It is a graph which shows the robustness of the mounting accuracy of a light emitting part. It is a graph which shows the robustness of the mounting accuracy of a light emitting part. It is a table which shows the degree of correlation between the wavelength of light of a light emitting part, and Beck smoothness. It is a graph which shows the comparison result of the Beck smoothness with 4 kinds of paper types (gloss paper, matte paper, plain paper, high-quality paper), and the predicted value by a measurement result. It is a block diagram which shows the structure of an image forming apparatus. It is a flowchart which shows the printing process of an image forming apparatus. It is a subroutine flowchart which shows the paper setting process (step S10). It is a control block diagram which shows the determination process (S107). This is an example of an operation screen showing the determination result (paper type / basis weight classification). This is an example of an operation screen showing a judgment result (registration profile).

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios. In the drawings, the vertical direction is the Z direction, the front and back directions of the image forming apparatus are the X directions, and the directions orthogonal to these X and Z directions are the Y directions. The X direction is also referred to as a width direction or a rotation axis direction. Further, in the vicinity of the media sensor (media sensor 15 described later), the transport direction of the recording medium parallel to the plane of the transport path (transport path 143 described later) inclined with respect to the horizontal plane and orthogonal to the X direction is the Y'direction. , The direction orthogonal to this is called the Z'direction (see FIG. 2 etc.). In the present embodiment, the recording medium includes printing paper (hereinafter, simply referred to as paper) and various films. In particular, the paper includes those produced using plant-derived mechanical pulp and / or chemical pulp. The types of recording media include coated paper, gloss-coated paper and matte-coated paper, and non-coated paper, such as plain paper and high-quality paper.

FIG. 1 is a diagram showing a schematic configuration of an image forming system 1 including an image forming apparatus 10 according to the present embodiment. As shown in FIG. 1, the image forming system 1 includes an image forming device 10, a paper feeding device 20, and a post-processing device 30 that are mechanically and electrically connected to each other.

(Image forming apparatus 10)
The image forming apparatus includes a control unit 11, a storage unit 12, an image forming unit 13, a paper feed transport unit 14, a media sensor 15, an operation panel 18, a communication unit (not shown), and the like. These are connected to each other via a signal line such as a bus for exchanging signals. FIG. 2 is a side view showing the configuration of the media sensor 15 arranged in the transport path 143. The media sensor 15 is composed of a paper thickness sensor 40, a basis weight sensor 50, a surface sensor 60, and a paper pressing portion 70, and measures paper characteristics. The surface sensor 60 functions as an "optical sensor device" and detects paper characteristics, particularly paper surface properties. Details of the media sensor 15 including the surface sensor 60 will be described later.

(Control unit 11)
The control unit 11 is composed of a CPU, ROM, RAM, etc., and executes various processes by executing a program stored in the ROM or the storage unit 12 described later, and controls each unit of the device and various types according to the program. Performs arithmetic processing.

(Memory unit 12)
The storage unit 12 includes an auxiliary storage unit such as a ROM for storing various programs and various data in advance, a RAM for temporarily storing programs and data as a work area, and a hard disk for storing various programs and various data. Further, the storage unit 12 stores the paper information stored in each paper feed tray. Paper information includes information on paper brand, size (paper width, paper length), basis weight (weight), and paper type (gloss coated paper, matte coated paper, plain paper, high quality paper, rough paper, etc.). , It is set by the paper type determination process described later. Further, the storage unit 12 may store the paper brand, the learned model used for determining the paper type, and the paper profile (both described later).

(Image forming unit 13)
The image forming unit 13 forms an image by, for example, an electrophotographic method. The image forming unit 13 is composed of a writing unit 131 corresponding to each of the basic colors of Y (yellow), M (magenta), C (cyan), and K (black), a photoconductor drum 132, and toners and carriers of each color. A developer 133, etc., which accommodates a two-component developer, and the like are provided. Further, the image forming unit 13 further includes an intermediate transfer belt 134, a secondary transfer unit 135, and a fixing unit 136. The toner images formed on the photoconductor drum 132 by the developer 133 of each color are superposed on the intermediate transfer belt 134 and transferred to the paper S conveyed by the secondary transfer unit 135. The toner image on the paper S is fixed on the paper S by being heated and pressurized by the fixing portion 136 on the downstream side.

(Paper feed transport unit 14)
The paper feed transport unit 14 includes a plurality of paper feed trays 141, 142, transport paths 143, 144, and the like. The transport paths 143 and 144 include a plurality of transport roller pairs provided along these transport paths and a drive motor (not shown) for driving these transport roller pairs. It is equipped with a delivery roller that feeds out the highest-ranked paper among the plurality of sheets S loaded and placed in the paper feed trays 141 and 142, and feeds the paper S in the paper feed tray one by one to the transport path on the downstream side. .. The media sensor 15 is arranged on the upstream side of the resist roller on the transport path 143. As shown in FIG. 2, in the vicinity of the media sensor 15, the transport path 143 includes an upper guide 1431 and a lower guide 1432 formed of sheet metal, and the paper S passes between these guides facing each other at predetermined intervals.

The paper feed transport unit 14 transports the paper S fed from the paper feed tray 141 or the like. The paper S conveyed through the transport path 143 is ejected onto the output tray 342 via the subsequent post-processing device 30 after the image is formed by the image forming unit 13. When performing double-sided printing in which an image is also formed on the back surface of the paper S, the paper S having an image formed on one side is conveyed to a transport path 144 for forming a double-sided image at the lower part of the main body of the apparatus. The paper S transported to the transport path 144 is inverted on the front and back by the switchback path, then merges with the transport path 143 for one side, and the image forming unit 13 again forms an image on the other side of the paper S. To.

(Operation panel 18)
The operation panel 18 is provided with a touch panel, a numeric keypad, a start button, a stop button, etc., displays the status of the image forming apparatus 10 or the image forming system 1, and is a type of paper placed on the paper feed tray 141 or the like from the user. It is used for setting etc. and inputting instructions.

(Paper Feeding Device 20)
As shown in FIG. 1, the paper feed device 20 includes a paper feed transfer unit 24. Further, the paper feed device 20 includes a control unit, a storage unit, and a communication unit (none of which are shown) in addition to the paper feed transport unit 24, and these include signal lines such as a bus for exchanging signals. They are connected to each other via. The paper feed transport unit 24 includes a plurality of paper feed trays 241, 242, 243, and a transport path 244. The paper S conveyed from each paper feed tray is conveyed to the image forming apparatus 10 on the downstream side, and the paper characteristics are measured by the media sensor 15 and the image is formed by the image forming unit 13.

(Post-processing device 30)
As shown in FIG. 1, the post-processing device 30 includes a post-processing unit 31, a transport path 341, and a paper ejection tray 342. The post-processing unit 31 performs processing such as stapling processing, cutting processing, punching processing (punching holes), and the like on the paper S conveyed from the image forming apparatus 10. Further, the post-processing device 30 includes a control unit, a storage unit, and a communication unit (none of which are shown) in addition to these components, and these include a signal line such as a bus for exchanging signals. To be connected to each other.

(Media sensor 15)
As described above, the media sensor 15 is composed of a paper thickness sensor 40, a basis weight sensor 50, a surface sensor 60, and a paper pressing portion 70. With reference to FIG. 2, among these components, the paper thickness sensor 40 is arranged on the most upstream side in the transport direction. The paper thickness sensor 40 includes a pair of transport rollers 411 and 412, and a pressing mechanism 42 including an actuator, an encoder, and a light emitting / receiving unit. The upper transport roller 411 is urged toward the lower transport roller 412 by the pressing mechanism 42. By transporting the paper S to the nips of the transport rollers 411 and 412, the transport roller 411 moves upward by a height corresponding to the thickness of the paper S. The pressing mechanism 42 detects the paper thickness of the paper S based on the amount of displacement of the transport roller 411 in the height direction (thickness direction).

FIG. 3 is a perspective view showing the configurations of the basis weight sensor 50 and the surface sensor 60. As shown in FIGS. 2 and 3, the basis weight sensor 50 and the surface sensor 60 are arranged side by side in the X direction (width direction) between the transport roller pairs 1433 and 1434.

The basis weight sensor 50 is a sensor that detects the basis weight of the paper, includes a light emitting unit and a light receiving unit, and measures the amount of attenuation of light transmitted through the paper S. For example, the basis weight sensor 50 has a light emitting unit 52 below the transport path 143 and a light receiving unit 51 above, and detects the basis weight of the paper S by the intensity of the light received by the light receiving unit 51.

(Surface sensor 60)
Next, the configuration of the surface sensor 60 will be described with reference to FIGS. 4 to 8 together with FIGS. 2 and 3. FIG. 4 is a cross-sectional view of the surface sensor 60, and FIG. 5 is a perspective view showing the internal configuration of the surface sensor 60. In FIG. 5, the description of the cover (housing 61) that covers the entire surface sensor 60 is omitted.

As shown in these figures, the surface sensor 60 includes a housing 61, a light emitting unit 62, a collimating lens 63, a plurality of light receiving units 64 (light receiving units 641, 642), and an opening / closing mechanism 65. The housing 61 covers other components and shields external light. The housing 61 is not on the bottom surface, and when attached, the upper guide 1431 functions as a member that covers the bottom surface of the surface sensor 60. Details of the light emitting unit 62, the collimating lens 63, and the plurality of light receiving units 64 (light receiving units 641, 642) will be described later. In this embodiment, a collimating lens is used as the optical system arranged between the light source and the irradiation region, but a lens other than the collimating lens may be arranged. For example, when a bullet-shaped LED is used, an optical lens is mounted on the LED. Further, a convex lens or the like may be arranged between the LED and the collimator lens.

The opening / closing mechanism 65 includes a shutter 651, a connection portion 652, a rotating shaft 653, a worm gear 654, and a drive motor 655. The power of the drive motor 655 is transmitted to the shutter 651 through the worm gear 654, the rotating shaft 653, and the connecting portion 652. The shutter 651 moves around the rotation axis 653 in the direction of the arrow. The upper guide 1431 is provided with an opening a1, and the lower guide 1432 is provided with an opening a20. 4 and 5 show a state in which the paper characteristics of the paper S in the normal state are not measured. At this time, the opening a1 is closed by the plate-shaped shutter 651 which is a flat plate member. The opening / closing operation of the opening a1 of the shutter 651 is performed by the control unit 11 controlling the drive motor 655.

FIG. 6 is a schematic cross-sectional view of the surface sensor 60 showing a state in which the shutter is open. FIG. 6 shows the state of the measurement mode for measuring the paper characteristics. In FIG. 6, the description of the configuration of the opening / closing mechanism 65 other than the shutter 651 is omitted. The opening a1 has a substantially rectangular shape, and the hole size is, for example, several tens of mm in the horizontal direction (X direction) and several tens of mm in the vertical direction (Y'direction). A plurality of ribs r1 (see FIG. 6) are provided on the lower surface of the shutter 651 so as not to interfere with the transport of the paper S in the transport path 143. Each rib r1 is inclined along the transport direction so that the lower surface of the upper guide 1431 is retracted on the upstream side in the transport direction and slightly protrudes on the downstream side. With such a rib r1, the paper S can be smoothly conveyed. Further, a reference plate 6501 as a member for calibration is attached to the upper surface of the shutter 651. The reference plate 6501 is, for example, a white plate having a predetermined surface property, and the surface property sensor 60 can be calibrated by measuring the reference plate 6501 of the closed shutter 651 before measuring the paper characteristics. Do.

The opening a20 is wider than the opening a1 and is at substantially the same position in the XY'plane, and the opening a20 includes the opening a1. A paper pressing portion 70 is arranged below the lower guide 1432. The paper pressing portion 70 includes a pressing plate 71 having an upper surface parallel to the XY'plane, and a driving mechanism (not shown) for moving the pressing plate 71 up and down. The drive mechanism is composed of a drive motor, a cam, a spring, and the like. Normally, the shape has a cut portion (inclined surface) in which the corner on the upstream side in the transport direction of the pressing plate 71 is slanted so that the paper S to be conveyed does not get caught in the corner, and the pressing plate 71 (excluding the cut portion) is formed. The upper surface is located at the same height as the paper passing surface of the lower guide 1432, or at a height slightly lower than this. The upper surface of the pressing plate 71 is sufficiently larger than the opening a1. In the measurement mode of FIG. 6, the tip of the paper S is transported to a position beyond the openings a1 and a20 in the transport direction, and then the paper S is temporarily stopped. After that, the pressing plate 71 is lifted by the driving mechanism of the paper pressing portion 70. As a result, the paper S is fixed between the upper surface of the pressing plate 71 and the lower surface (reference surface) of the upper guide 1431 with a predetermined urging force. For example, the upper surface of the pressing plate 71 has a size larger than a dozen mm width or more over the entire circumference of the opening a1, and the paper S is pressed in the width region around the pressing plate 71.

FIG. 7 is a schematic view showing the arrangement positions of the light emitting unit 62 and the plurality of light receiving units 64, and FIG. 8 is a cross section showing the incident angle (irradiation angle) of the irradiation light by the light emitting unit 62 and the arrangement angle of the light receiving unit. It is a schematic diagram. In the present embodiment, the arrangement angle of the light emitting unit 62 is set so that the incident angle of the irradiation light with respect to the reference plane is 75 °. The incident angle of 75 ° is an angle used for measuring the glossiness of blank paper according to JIS, and is an angle that is less affected by the color of the object to be measured. The reference surface is a virtual surface including the lower surface of the upper guide 1431 as described above, and at the time of measurement, the surface of the paper S to be measured is arranged on the reference surface. The light emitting unit 62 is arranged on the substrate b1. The light emitting unit 62 includes a light emitting element as a light source such as an LED that emits light having a predetermined wavelength (for example, an average wavelength of 445 nm or more and 500 nm or less), and the irradiation light emitted from the light source (point light source) is abbreviated by the collimating lens 63. It becomes parallel light and irradiates the irradiation area. The irradiation region is an inner region of the opening a1 when viewed from the Z'direction, and the center (optical axis) of the irradiation region and the reference plane parallel to the XY'plane intersect at the intersection p1. As the light emitting unit 62, a surface light emitting type LED may be used, or a bullet type LED may be used. Further, when a bullet-shaped LED is used, a desired irradiation diameter (also referred to as a beam diameter) can be obtained by designing a lens suitable for the bullet-shaped directivity.

Each of the plurality of light receiving units 64 includes a light receiving element such as a photodiode, a phototransistor, etc., and a first light receiving unit 64 (light receiving unit 641) that receives specularly reflected light from the irradiation region and diffuse reflection from the irradiation region. Includes one or more second light receiving units 64 (light receiving units 642) that receive light. As shown in FIG. 7 (see also FIG. 8 for the angles of incidence and reflection), the first light receiving unit 641 is located at a reflection angle of 75 ° corresponding to the incident angle of 75 ° of the light emitting unit 62. It is placed in and receives specularly reflected light. Further, the second light receiving unit 642 can be arranged at any position of the reflection angle except the position of 75 ° within the range of the reflection angle of 0 ° or more and less than 90 °, and receives diffuse reflected light. The arrangement positions are preferably reflection angles of 60 °, 30 °, and 0 °, and more preferably two locations of 60 ° and 30 °, or one location of 60 °. In the examples of FIGS. 4, 6 and 7, a first light receiving unit 641 for receiving specular reflected light having a reflection angle of 75 ° and a second light receiving unit 642 for receiving diffuse reflected light having a reflection angle of 30 ° are arranged. An example of this is shown. In these figures, the light receiving unit 641 is arranged on the substrate b2, and the light receiving unit 642 is arranged on the substrate b3.

The housing 61 is provided with openings a3 and a4 on the light receiving path of the light receiving portions 641 and 642. Since the openings a3 and a4 have the same structure, the structure of the openings a3 will be described below as a representative. As shown in the partially enlarged view of FIG. 7, the opening a3 is, for example, a circular slit having a diameter of 3 mm when viewed from the intersection p1 side, and an inclined surface 61a is provided on the light incident side. The inclined surface is configured so that the distance from the optical axis increases toward the incident side, and has a mortar-shaped shape as a whole. The inclination angle is about 45 ° with respect to the incident angle of light. By providing such an inclined surface 61a, it is possible to prevent the light reflected by the edge of the opening a3 (slit) from being incident on the light receiving portion 641, and by extension, the characteristics of the recording medium can be detected with high accuracy.

(Irradiation diameter)
FIG. 9 is a schematic view showing a microscopic variation state of fiber orientation of paper, and FIG. 10 is a schematic view showing a state of pulp fibers on the surface of paper. Generally, paper is made by randomly entwining pulp fibers extracted from plants such as wood in all directions (isotropic), so that the surface becomes uneven and the surface surface has uneven distribution. (Also called "formation" in industry terms). This texture depends on the length and thickness of the pulp fibers of the paper. The unevenness is larger in B of FIG. 9 than in A of FIG. Pulp fibers derived from softwood and hardwood are used as the material of the paper, and the pulp fibers have an average length of 3.32 mm to 0.79 mm (maximum of about 5.7 mm) and an average width (thickness). 39 μm to 19 μm (maximum approx. 97 μm) (Reference: Paper “Measurement of Surface Shape of Paper” (Paper Pulp Gikyo Magazine Vol. 18, No. 2, February 1964), Oji Paper Co., Ltd. Central Research Institute Hata By Kotoku). Further, as shown in FIG. 10, the surface properties become non-uniform due to the length of the pulp fibers and the formation of binding fibers (entanglement of fibers) between the pulp fibers.

Therefore, if the irradiation diameter is narrowed down too much from the length of the pulp fiber and the shape of the binding fiber, the detected light amount of the specular reflected light and the diffused light differs depending on the position of the reflected light on the paper, that is, the uneven state on the paper surface, which is the same. It is a sensor that is highly sensitive to the surface condition of the paper even on the paper surface. Therefore, an error occurs in each reflected light amount, and if the paper type is discriminated using the data while the error is included, there is a possibility that the paper type is erroneously discriminated. For example, matte coated paper is misidentified as high-quality paper.

11A and 11B are schematic views showing the surface distribution of the paper and the diffusion state of the irradiation light, and FIGS. 12A and 12B are schematic views showing the irradiation diameter of the irradiation light and the arrangement position of the light emitting portion 62. 12 (a) is a side view, and FIG. 12 (b) is a top view. In the present embodiment, from such a situation, it is better to irradiate a wide area as shown in FIG. 11 (b) than to irradiate a narrow area as shown in FIG. 11 (a). The influence of can be reduced. In other words, by setting the irradiation diameter of the irradiation light to a size that irradiates an area sufficiently wider than the area where the pulp fibers that cause the distribution of the paper surface are entangled, the average of the paper surface including the unevenness of the paper surface is obtained. The amount of reflected light can be reduced, and the influence of the distribution on the paper surface can be reduced. Specifically, the irradiation diameter in the irradiation region is set to 6 mm or more, which is larger than the maximum length of the pulp fiber of 5.7 mm described above. The irradiation diameter referred to here is the diameter of the light (beam) in a plane orthogonal to the optical axis at the intersection p1 where the optical axis intersects the irradiation surface (reference plane). Generally, the focal length of the lens, the size of the light source, and the spread of the irradiation diameter are
(Expansion of irradiation diameter) ≒ (light source size) / (lens focal length) ... It is expressed by equation (1). From this equation, the longer the focal length, the closer to parallel light, but the amount of irradiation light decreases, so it is necessary to brighten the lens. Generally, as an expression expressing the brightness of a lens,
(Brightness of lens) = (Focal length of lens) / (Diameter of lens) ... It is expressed by equation (2). From equation (1), the irradiation diameter can be expanded by having a certain size of the light source. That is, in order to obtain the set irradiation diameter and irradiation light amount, the above-mentioned conditions are obtained from the optical design.

In this embodiment, the irradiation diameter is set to φ13 mm as shown in FIG. 12 (a). In order to obtain such an irradiation diameter, when the lens specifications are used with a focal length of 20.7 mm and a lens diameter of φ7.5 mm from optical design and optical simulation, the distance from the light emitting portion 62 to the intersection p1 is 50 to 70 mm. It is within the range, for example 60 mm. As shown in FIG. 12B, the irradiation diameter when designed in this way is φ13 mm for the minor axis (length in the Y'direction) and the major axis (length in the X direction) in the top view (on the XY'plane). Is 50.2 mm (= 13 / cos 75 °). With such an irradiation area (512.6 mm ² ), it is possible to detect the amount of specularly reflected light or diffused light with low sensitivity to the surface surface distribution of the paper, resulting in non-uniform fiber orientation. Less sexual influence.

FIG. 13 is a graph showing the variation in the amount of detected light due to the difference in the irradiation diameter when the surface of the paper is measured at a plurality of points. The figure shows the sample numbers at two levels, the irradiation diameter of φ13 mm and the irradiation diameter of φ1 mm. 1-NO. Up to 10, the variation in the amount of detected light when measuring the positions of 10 different points on one sheet of plain paper is shown. ± 8% shown in the figure is a threshold value at which false detection of paper discrimination is likely to occur as described below. If the irradiation diameter is small, it is easily affected by the texture of the paper S, and erroneous determination of the paper type is likely to occur. As shown in FIG. 13, the irradiation diameter of φ13 mm has less variation in false positives than the irradiation diameter of φ1 mm, and is within the threshold value of ± 8%.

FIG. 14 is a graph showing the transition of the detection accuracy when an error is added to the input data when the paper is discriminated by using the machine-learned model (FIGS. 18 to 20 described later). The figure shows an example in which a gloss paper “coat ball” is used as the paper type. The "coated ball" was used because it is the paper that is most likely to be erroneously discriminated with respect to the reflection angle of 75 ° among 58 types of paper including this. When an error is artificially input to the value measured by the first light receiving unit 641 for detecting specular reflected light with a reflection angle of 75 °, the first candidate for judgment is from the original (correct judgment) gloss paper. It shows the threshold value that causes a false judgment with different matte paper (minus side of X-axis error). If an error having an absolute value larger than −8% is input, an erroneous determination will occur in the first candidate for determination, so the threshold value of the specularly reflected light detection unit having a reflection angle of 75 ° is set to ± 8%. That is, the sensor detection accuracy of the reflection angle of 75 ° was set within ± 8%. In the above, the reflection angle of 75 ° has been described, but as a result of performing the same verification for each of the reflection angles of 30 ° and 60 ° (not shown), the threshold value at which the first candidate is erroneously determined is larger than ± 8%. From the verification results, ± 15% was adopted as the respective threshold values of the reflection angles of 30 ° and 60 °. That is, the sensor detection accuracy of the reflection angles of 30 ° and 60 ° was set within ± 15%.

(Position of light source with respect to focal length)
With reference to FIG. 12B again, the arrangement position of the light emitting unit 62 as the light source of the surface sensor 60 (optical sensor device) according to the present embodiment will be described. A collimating lens 63 is arranged immediately downstream of the light emitting unit 62. In general, by arranging a point light source at the focal position of a collimating lens, that is, by arranging the light source at the same distance as the focal length with respect to the collimating lens on the optical axis, the irradiation light from the point light source is emitted. Make it parallel light. In the first embodiment, the light source is arranged at the position of the focal length in this way. However, in the second embodiment, the light emitting unit 62 is intentionally arranged on the side closer to the collimating lens 63 at a distance shorter than the focal length. That is, the focal length f> the light source distance t0 is set (where t0 is the distance between the light emitting portion 62 and the center position of the collimating lens 63 on the optical axis, and f is the focal length of the collimating lens 63. is there).

15A and 15B are graphs showing the robustness of the mounting accuracy of the light emitting unit 62. FIG. 15A is a diagram showing the output error sensitivity to the mounting error in the rotation direction, and FIG. 15B is a diagram showing the output error sensitivity to the mounting error in the optical axis direction. Along with Example 2, data when a light source is arranged at a focal length is also shown as Example 1 to be compared. Here, the mounting error in the rotation direction is an angle when the axis perpendicular to the optical axis is rotated as the rotation axis (corresponding to YAW). The mounting error in the optical axis direction is the distance in the front-rear direction along the optical axis. As shown in FIGS. 15A and 15B, as compared with Example 1, Example 2 in which the light source is arranged at a distance shorter than the focal length of the collimating lens has less variation with respect to error, has higher robustness, and is superior. You can see that.

(Wavelength of light from light source)
For the light wavelength of the light emitting unit 62, a light source having a blue wavelength that is not absorbed by the pigment on the surface layer of the coated paper is selected. From the experimental verification of the LED, the following results were obtained.
405 nm (purple): Coated paper can be identified (specular reflection). Diffuse light makes it difficult to identify high-quality, plain paper.
465 nm (blue): Coated paper can be identified (specular reflection). Diffused light can be identified at 30 ° and 60 °.
525 nm (green): Coated paper can be identified (specular reflection). Diffuse light can be identified at 60 °.
680 nm (red): Difficult to distinguish, especially with diffused light.

In addition, as shown below, regarding the correlation with Beck smoothness, the correlation with each wavelength was also verified.

FIG. 16 is a table showing the degree of correlation between the wavelength of light of the light emitting unit 62 and the Beck smoothness, and FIG. 17 shows Beck on 12 types of paper (gloss paper, matte paper, plain paper, woodfree paper). It is a graph which shows the comparison result of the smoothness, and the predicted value by the measurement result. Here, Beck smoothness (sec) is a measurement method specified in JIS. After applying a pressure of 0.1 MPa from above and reducing the pressure to half atm with a vacuum pump, 10 cc of air passes through a distance of 13 mm. Measures the time of inflow from the gap between the sample surface and the glass surface.

The light emitting unit 62 was arranged at a position where the incident angle was 75 °, and three types of LEDs having wavelengths of 405 nm, 465 nm, and 525 nm were used as the light source. Further, the light receiving portions 64 were arranged at three locations having reflection angles of 30, 60, and 75 ° (note that they were arranged at all four locations in the test at a wavelength of 525 nm, and further arranged at 0 °).

As the paper type, four types of paper, gloss paper, matte paper, plain paper, and high-quality paper, were used, and four different brands of paper were used (16 brands in total). On the horizontal axis of FIG. 17, four brands of gloss paper are indicated by G1 to G4, four brands of matte paper are indicated by M1 to M4, four brands of plain paper are indicated by R1 to R4, and four brands of woodfree paper are indicated by F1 to F4. There is.

As shown in FIG. 16, the smoothness predicted value calculated by multiplying the measured value from each light receiving unit 64 by a predetermined coefficient for each of the 16 brands of paper, and the measured value of the Beck smoothness of each paper ( When the correlation with log) was compared, it was found that the value of the multiple correlation R was the highest when the LED having an average wavelength of 465 nm was used (indicated by the broken line frame). From this, the wavelength of the light source is preferably in the range of more than 405 nm and less than 525 nm, more preferably in the range of 445 nm or more and 500 nm or less, and the most preferable wavelength is around 465 nm.

FIG. 17 shows the correspondence between the predicted value when the 465 nm LED is used and the Beck smoothness (log). The predicted value here is
Predicted value = 3.4518 × V75-3.9595 × V60 + 1.5383 × V30-0.4789. Here, V75, V60, and V30 are the output values of the light receiving unit 64 at the positions of the reflection angles 75, 60, and 30 °, respectively. As shown in FIG. 17, it can be seen that there is a high correlation.

(Effect of this embodiment)
In the optical sensor device (surface sensor 60) according to the present embodiment, the irradiation diameter in the irradiation region of the irradiation light by the light emitting unit 62 is the irradiation area in which the influence of the non-uniformity of the fiber orientation of the recording medium is reduced. Is set to. More specifically, the irradiation diameter (minor diameter) in the irradiation region (intersection point p1) is set to 6 mm or more, which is longer than the maximum length of the pulp fibers. This provides an optical sensor device that can accurately detect the characteristics of the recording medium without being affected by the surface distribution of the recording medium.

Further, the collimating lens 63 is arranged immediately downstream of the light emitting unit 62, and the light emitting unit 62 is arranged at a distance shorter than this focal length with respect to the collimating lens 63 on the optical axis. This makes it possible to improve the robustness of the light emitting unit 62 with respect to the mounting accuracy.

Further, by setting the emission wavelength of the light emitting unit 62 to 445 nm or more and 500 nm or less, the surface property can be detected with high accuracy. Specifically, it is possible to obtain detection data having a high correlation with Beck smoothness.

Further, the optical sensor device according to the present embodiment is provided with a shutter 651 that opens and closes the opening a1 constituting the irradiation region. For example, when the optical sensor device is arranged in the paper transport path, the paper dust of the paper S to be transported may adhere to optical parts such as the collimating lens 63 and the light receiving portion 64, and the measurement accuracy may be lowered. When the surface property of the recording medium is not measured, by closing the opening a1 with such a shutter 651, it is possible to prevent the optical components of the optical sensor device from being contaminated by paper dust, and thus to prevent the measurement accuracy from being lowered.

(Paper type judgment processing)
Next, the paper type determination process performed by the image forming apparatus 10 will be described with reference to FIGS. 18 to 21. FIG. 18 is a block diagram showing a configuration of an image forming apparatus. FIG. 19 is a flowchart showing a printing process of the image forming apparatus.

As shown in FIG. 18, the image forming apparatus 10 is connected to the server 80 and other image forming apparatus 10b and 10c through the network 90. In the figure, since the configurations other than the control unit 11 of the image forming apparatus 10 have already been described in FIG. 1 and the like, the description will be omitted by adding the same reference numerals.

The control unit 11 functions as an overall control unit 110, an engine control unit 120, a media sensor control unit 130, a post-processing option control unit 140, a paper feed option control unit 150, and a transport control / image formation control unit 160.

When a print job is input by an instruction sent from an operation panel 18 or an external terminal such as a network-connected PC operated by the user, the overall control unit 110 is based on the input print setting information of the print job. , The engine control unit 120 executes a print job. The overall control unit 110 executes the paper type determination process by using the paper type determination engine (learned model) stored in the storage unit 12 and the paper profile. Here, the "paper profile" is a measured value related to the physical characteristics of the paper obtained from the media sensor 15 of the paper, the calculated value of the positioning value, and the characteristic data, the paper size, and any arbitrary value input by the user. It is registered in advance by associating an identification name (for example, a paper brand), etc. The measured values and calculated values from the media sensor 15 include, for example, the measured values of the reflected light at 75 ° and 30 ° of the surface property sensor 60 of the paper physical properties, and the basis weight based on the measured values of the basis weight sensor 50, which will be described later. There is a calculated value of, / or a calculated value of the basis weight difference, and a calculated value of the paper thickness based on the measured value of the paper thickness sensor 40. In addition, the characteristic data input by the user includes transport system characteristic data (front and back adjustment values, offset correction values, etc.), image formation characteristic data (fixation temperature value, density adjustment value, γ correction value, etc.), Includes various control parameter values such as paper feed system characteristic values (paper feed tray handling fan air volume adjustment value).

The "paper type discrimination engine" is also called a learned model, and a teacher using teacher data with the detection output by the media sensor 15 of the paper S as an input value and the paper type information set by the user of the paper S as a correct label. It is a trained model generated by Yes training. As the teacher data, the data of other image forming devices 10b, 10c, etc. connected to the network 90 may be aggregated by the server 80. The learning machine (not shown) can generate a trained model by a learning method using a neural network constructed by combining perceptrons. The learning method is not limited to this, and various methods can be adopted in the case of supervised learning. For example, a random forest, a support vector machine (SVM), a boosting method, a Bayesian network linear discrimination method, a non-linear discrimination method, and the like can be applied. Further, as a learning machine, it can be performed by using a stand-alone high-performance computer using a CPU and a GPU (Graphics Processing Unit) processor, or a cloud computer.

The engine control unit 120 performs processing related to image formation by controlling the post-processing option control unit 140, the paper feed option control unit 150, and the transport control / image formation control unit 160. The post-processing option control unit 140 controls the post-processing device 30. Specifically, the paper transport timing, post-processing setting information of the paper to be transported, and the like are transmitted to the post-processing device 30. The paper feed option control unit 150 controls the paper feed device 20. Specifically, by communicating with the paper feed device 20, the paper feed tray to be used, the paper transfer timing, and the like are transmitted and received.

The transport control / image formation control unit 160 controls the paper feed transport of the paper S by controlling the paper feed transport unit 14 (including drive motors such as the transport paths 143 and 144 and the fixing unit 136). In addition, the image forming unit 13 is controlled to control the image forming conditions and the image forming timing according to the paper position.

The media sensor control unit 130 controls the paper thickness sensor 40, the basis weight sensor 50, and the surface sensor 60 in response to an execution instruction request from the engine control unit 120 to execute measurement of paper characteristics. Further, the media sensor control unit 130 controls the operation of the paper pressing unit 70.

Next, the paper type determination process will be described with reference to FIG. Steps S10 to S30 are print preparation processes. The user performs this print preparation process before performing the main printing of the print job.

(Step S10)
The user operates the paper setting button on the operation screen (not shown) displayed on the operation panel 18. The control unit 11 starts the paper setting by accepting this operation from the user. The start instruction of the paper setting includes selection information of one or more paper feed trays (paper feed trays 141, 142, 241 to 243) in which the target paper is loaded. Details of this paper setting process will be described later with reference to FIG.

(Step S20)
When the paper setting is completed, the image formation conditions are set according to the set paper characteristics, and test printing (test printing) of the print job is performed.

(Step S30)
When the user is unsatisfied with the result of the test print, or when a plurality of types of paper are used in one print job, the user repeats the process of step S10 or less for another paper (step S30: NO). On the other hand, when the result of the test print is satisfactory and the confirmation regarding all the paper types is completed (YES), the control unit 11 advances the process to step S40 by accepting the operation of the preparation completion by the user. ..

(Step S40)
The control unit 11 controls the image forming unit 13 and the like to execute a print job (main printing), thereby completing the printing process (end).

(Paper setting process)
(Steps S100, S101)
FIG. 20 is a subroutine flowchart showing the paper setting process (step S10). The transport control / image formation control unit 160 of the control unit 11 opens the shutter 651 by the opening / closing mechanism 65, and then the paper feed tray selected by the user (for example, the paper feed tray 141 (hereinafter, simply “selection tray””). )), The paper S is fed and transported to the transport path 143.

(Step S102a)
The media sensor control unit 130 detects the paper thickness of the paper S by the paper thickness sensor 40, and passes the detection data (hereinafter, referred to as “measured value 1”) to the overall control unit 110.

(Steps S102b, S102c)
The media sensor control unit 130 detects the basis weight and surface quality of the paper by the basis weight sensor 50 and the surface surface sensor 60, and controls the detection data (hereinafter referred to as “measured values 2 and 3”, respectively) as a whole. Hand over to unit 110. In this measurement, when the tip of the paper S passes the detection positions of the predetermined amount, the basis weight sensor 50, and the surface sensor 60, the paper transport is stopped at one end, the pressing plate 71 of the paper pressing portion 70 is lifted, and the surface is measured. The paper S located in the irradiation area of the sex sensor 60 is fixed. Before this first measurement, the surface sensor 60 may be calibrated by the reference plate 6501.

(Step S103)
If the measurement has not been performed a predetermined number of N times, the processes of steps S102b and S102c are repeated. Before performing the next measurement, the same paper is obtained by moving the paper pressing portion 70 up and down and transporting the paper S for a predetermined distance (for example, an arbitrary distance of about several mm to 50 mm) each time. Measure another position of S. The N times is, for example, 5 times, and when the measurement for 5 times is completed (YES), the process proceeds to step S104.

(Step S104)
When the rear end of the paper S has passed through the media sensor 15, specifically, when the paper sensor (not shown) detects that the rear end of the paper S has passed through the transport roller 1434 (YES), the process is performed. Proceed to step S105.

(Step S105)
Here, the control unit 11 closes the shutter 651 by the opening / closing mechanism 65 to bring it into a closed state. This prevents the surface sensor 60 from being contaminated by paper dust or the like due to the paper S that is conveyed when the measurement is not performed by the media sensor 15.

(Step S106)
Here, averaging processing is performed on the detection data (measured values 2 and 3) of the basis weight and surface properties of N times acquired in steps S102b and S102c.

(Step S107)
The overall control unit 110 determines the paper type by using the measured values 1 to 3 (or the average data thereof) acquired in steps S102a to S102c, the trained model (paper type determination engine), and the basis weight division probability calculation process. , And the basis weight classification is determined. Further, the candidate of the paper profile having a high degree of approximation is determined from the registered paper profile data by using the measured values 1 to 3 (or the average data thereof) acquired in steps S102a to S102c and the profile selection process.

The paper type determination and the basis weight classification determination process will be described in more detail with reference to FIG. FIG. 21 is a control block diagram showing a determination process (S107). In FIG. 21, in addition to the paper type determination and the basis weight classification determination process, the determination process of the registered profile candidate determined by using the paper profile created for each user (for each device) is also shown.

(S701 to S703)
The overall control unit 110 obtains a basis weight conversion value, a paper thickness conversion value, and a surface property measurement value by using the measurement values 1 to 3 acquired in steps S102a to S102c. Here, the basis weight conversion value is the first basis weight and the first basis weight based on the coefficient and calculation formula determined by the surface property measurement value (S703) of the measurement value 3 and the ambient environment information (temperature, humidity) of the image forming system 1. From the value of 2 tsubo, the tsubo and the difference in tsubo (basis index value) are calculated. Here, the basis weight difference = 1st basis weight − 2nd basis area. The basis weight sensor 50 includes a plurality of LEDs that irradiate irradiation light having different wavelengths. The first basis weight is determined by the amount of transmitted light passing through the paper S of the irradiation light using the first LED that outputs the irradiation light having a wavelength (750 nm to 900 nm). The second basis weight is determined by the amount of transmitted light passing through the paper S of the irradiation light using the second LED that outputs the irradiation light having a wavelength (400 nm to 470 nm). The basis weight is sent to steps S711, S712, S714, and the basis weight difference is sent to steps S713, S714. The paper thickness is sent to steps S712 and S713. The surface quality measurements are sent to steps S701, S713, S714.

(Step S711)
The overall control unit 110 calculates the basis weight classification probability from the basis weight calculated in step S701. Examples of the basis weight classification are the following 12 classifications.
~ 61g / m ²
62-75 g / m ²
76-81 g / m ²
82-92 g / m ²
93-106 g / m ²
107-136 g / m ²
137-177 g / m ²
178-217 g / m ²
218-257 g / m ²
258-301 g / m ²
302-351 g / m ²
352 g / m ² ~
The calculated basis weight is assumed to vary with a predetermined standard deviation according to a normal distribution, and the probability of each division is determined. For example, when it is close to the center of any of the divisions, the division probability is high and is close to 100%. On the other hand, the farther from the center of the division, that is, the closer to the boundary, the lower the probability. The division probability is sent to step S721 as a basis weight division score.

(Step S712)
The overall control unit 110 calculates the density (= basis weight / paper thickness) using the basis weight and the paper thickness. The calculated density is sent to step S713.

(Step S713)
The overall control unit 110 discriminates the paper type by using the paper characteristic data of the measured values of density, paper thickness, and surface property and the trained model. The determination result is sent to step S721 as a paper type score.

(Step S714)
The overall control unit 110 uses the paper characteristic data of the measured values of density, paper thickness, and surface property and the list of paper profiles registered in advance by the user or the like, and selects a registered profile having a high conformance rate from the list. .. This list of paper profiles has data representing the physical characteristics of the paper, which consists of the basis weight value, the paper thickness value, the basis weight difference value, and the surface property measurement value (for example, the measurement value from the light receiving units 641 and 642). Using the measured values 1 to 3 (or these calculation data) acquired in steps S102a to S102c, the overall control unit 110 uses the paper profiles in the order closest to the registered paper physical property data from the registered paper profiles. Select candidates for. The selection result is sent to step S722 as a candidate paper profile list with a matching rate score.

(Step S721)
The overall control unit 110 displays one or a plurality of paper type / basis weight candidates in descending order of probability according to the basis weight classification score and the paper type score, and presents them to the user.

FIG. 22 is an example of the operation screen 181 showing the determination result (paper type / basis weight classification) displayed on the operation panel 18. On the operation screen 181, two paper type / basis weight candidates are displayed in descending order of score. When the user accepts the determination result of the first candidate column 81 (coated paper / basis weight 177 to 216), the user is selected for the tray 1 (paper feed tray 141) by operating the button 84. The determination result in column 81 is applied. When applying the second candidate column 82 (plain paper / basis weight 172 to 216), the user operates the button 84 after selecting the column 82. On the other hand, when it is desired to apply the selected determination result to both trays 1 and 2, the user operates the button 85. Further, by operating the button 83, the determination result can be discarded without being adopted. The determination result selected by the user may be stored in the server 80 or the like as correct answer data, and may be used as teacher data for subsequent machine learning.

(Step S722)
The overall control unit 110 displays one or a plurality of registered profile candidates in descending order of the score according to the precision score, and presents the candidates to the user.

FIG. 23 is an example of the operation screen 182 showing the determination result (registration profile) displayed on the operation panel 18. On the operation screen 182, three registration profile candidates are displayed in descending order of score. The registration profile registers the paper characteristics previously measured by the media sensor 15 or the paper characteristics manually input through the operation panel 18 in association with the media name. If the paper characteristics are the same as those measured in the past, the registered media name is displayed as the first candidate. When accepting the determination result of the column 86 (paper profile data 21) which is the first candidate, the determination result of the selected column 86 is applied to the tray 1 or the like by operating the buttons 84, 85, etc. To.

(Step S108)
See FIG. 20 again. Here, the overall control unit 110 displays the determination result. This process corresponds to FIGS. 22, 24, and steps S721 and S722 described above.

(Step S109)
If the user changes the paper type (YES), the process proceeds to step S110, and if the determination result is accepted without the change (NO), the process proceeds to step S111.

(Step S110)
The overall control unit 110 accepts an input operation from the user through the operation panel 18, and sets the accepted changed paper type as the paper type information of the selection tray.

(Step S111)
When the setting is not changed (for example, when the operation of the button 84 is accepted in FIG. 22), the overall control unit 110 sets the determination result performed in step S107 as the paper type information of the selection tray.

(Step S112)
The print condition of the selected tray is set to the print condition corresponding to the set paper type, and the process returns to the process of FIG. 19 and the process of step S10 or less is performed (return).

As described above, in the image forming apparatus 10 according to the present embodiment, the paper type of the recording medium is determined by using the detection result from the optical sensor apparatus. This makes it possible to accurately determine the paper type.

The configurations of the optical sensor device (surface sensor 60) and the image forming apparatus 10 including the optical sensor device (surface sensor 60) described above are limited to the above configurations, as the main configurations have been described in explaining the features of the above embodiments. However, various modifications can be made within the scope of the claims. Further, the configuration provided in a general optical sensor device or an image forming device is not excluded. For example, the example in which the optical sensor device is arranged on the transport path 143 of the image forming apparatus 10 is shown, but the present invention is not limited to this, and the apparatus may be independent of the image forming apparatus 10. In this case, the user can measure the paper characteristics by arranging the paper in the irradiation area of the optical sensor device.

Further, although the example in which the overall control unit 110 has the trained model is shown, the present invention is not limited to this, and the server 80 may have the trained model and the server 80 may determine the paper type. In this case, the image forming apparatus 10 transmits the measured paper characteristic data to the server 80, and the server 80 that receives the data determines the paper type based on the data and sends the determination result back to the image forming apparatus. .. Further, in FIG. 1 and the like, the image forming apparatus 10 shows a configuration in which the image forming apparatus 10 is connected to the optional paper feeding apparatus 20 and the post-processing apparatus 30, but the image forming apparatus 10 may be a single image forming apparatus 10 without these options.

Further, in the present embodiment, as a result of determining the paper type, as shown in FIG. 22, an example in which the priority (“recommendation”) is displayed in descending order of priority (score) is shown. The display may be omitted. Also, if there is only one candidate (or if there is a dissociation of the difference from the second and subsequent values by a predetermined value or more), it is automatically applied to the selected paper feed tray in order to improve operability. Then, the operation screen on which the operation of the test printing (step S20) can be executed immediately (with one touch) may be displayed.

1 Image formation system 10 Image formation device 11 Control unit 110 Overall control unit 14 Transport unit 141, 142 Paper feed tray 143, 144 Transport path 1431 Upper guide a1 Opening 1432 Lower guide 15 Media sensor 40 Paper thickness sensor 50 Basis weight sensor 60 Surface Sex sensor (optical sensor device)
61 Housing a3, a4 Opening 61a Inclined surface b1, b2, b3 Board 62 Light emitting part 63 Collimating lens 64, 641, 642 Light receiving part 70 Paper pressing part 18 Operation panel 20 Paper feeding device 30 Post-processing device 80 Server

Claims (10)

Light source and
An optical system that irradiates the surface of a recording medium in the irradiation region with light from the light source at a predetermined angle of incidence.
A first light receiving unit that detects the amount of specularly reflected light that is specularly reflected on the surface of the recording medium in the irradiation region, and
A second light receiving portion for detecting the amount of diffusely reflected light diffusely reflected at at least one reflection angle on the surface of the recording medium in the irradiation region is provided.
An optical sensor device in which the irradiation diameter of light emitted from the light source in the irradiation region is set to an irradiation diameter at which the influence of non-uniformity of fiber orientation of the recording medium is reduced. The optical sensor device according to claim 1, wherein the irradiation diameter in the irradiation region is 6 mm or more. The optical sensor device according to claim 1 or 2, wherein the optical system includes a collimating lens. The optical sensor device according to claim 3, wherein the light source is arranged on the optical axis at a distance shorter than the focal length of the collimating lens with respect to the collimating lens. The optical sensor device according to any one of claims 1 to 4, wherein the emission wavelength of the light source is 445 nm or more and 500 nm or less. The first and second light receiving units are each provided with a slit provided in the light receiving path and a photodiode that receives incident light that has passed through the slit.
The optical sensor device according to any one of claims 1 to 5, wherein the slit has an inclined surface that is inclined so that the distance from the optical axis increases toward the incident side. A transport unit that transports the recording medium to a transport path provided with an irradiation area,
The optical sensor device according to any one of claims 1 to 6.
At least the detection results of the amount of specularly reflected light and diffusely reflected light from the surface of the recording medium conveyed to the irradiation region, which are detected by the first and second light receiving portions of the optical sensor device, are used at least. An image forming apparatus including a control unit for determining a paper type of the recording medium. The transport path includes an upper guide and a lower guide, and the irradiation region is an inner region of an opening provided in the upper guide.
Further, a shutter for opening and closing the opening is provided.
When the paper type of the recording medium is not determined, the opening is closed by the shutter.
The image according to claim 7, wherein the paper type of the recording medium is determined by opening the opening with the shutter and using the detection result of the optical sensor device to determine the paper type of the recording medium. Forming device. The image forming apparatus according to claim 8, wherein the shutter is a flat plate member, and a calibration member is attached to one surface of the plate member. The image forming apparatus according to any one of claims 7 to 9, wherein the control unit determines the paper type by using a learned model for determining the paper type obtained by machine learning.

Images