JP2017129466A - Detector and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy in distinguishing between different objects having similar optical characteristics.SOLUTION: A detector 100 comprises: a reflected light measuring part R that detects light reflected on an object; and a thermal conductivity measuring part H that measures the thermal conductivity of the object. The detector 100 further includes a distinguishing part 304 that distinguishes between objects on the basis of an output from the reflected light measuring part R and an output from the thermal conductivity measuring part H. This can improve the accuracy in distinguishing between different objects having similar optical characteristics.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a detection apparatus and an image forming apparatus.

A technique for discriminating the characteristics and types of an object by optical measurement is useful in a wide range of fields. As an example, there is discrimination of recording paper (recording medium) for image formation. Image forming apparatuses such as digital copying machines and laser printers transfer a toner image onto the surface of recording paper represented by printing paper, and fix the image by heating and pressurizing under predetermined conditions to form an image. ing. Conditions such as heating and pressurization during image formation greatly affect image quality. Since these appropriate conditions vary depending on the type of recording paper, it is required to correctly determine the type of recording paper.
For this reason, a light receiver that receives the P-polarized light component contained in the internally diffuse reflected light and a light receiver that is arranged so as to mainly receive the regular specularly reflected light are provided. From the output signal of each light receiver, An optical sensor capable of specifying a brand is disclosed (Patent Document 1).

  However, there is a problem that even if optical measurement is performed on different objects having similar optical characteristics, it is not possible to obtain discrimination accuracy for distinguishing the objects as different ones.

  The present invention includes a light source, a light detection unit that detects reflected light of light emitted from the light source and reflected by the object, a heat transfer characteristic measurement unit that measures the temperature of the object, and the light detection unit. It is a detection apparatus provided with the discrimination | determination part which discriminate | determines the said object based on the reflected light characteristic of the said object obtained from an output, and the heat transfer characteristic of the said object obtained from the output of the said heat transfer characteristic measurement part.

  According to the present invention, it is possible to improve the discrimination accuracy of an object having similar optical characteristics.

1 is an explanatory diagram of a schematic configuration of a color printer according to an embodiment of the present invention. It is a hardware block diagram which shows the control apparatus which concerns on one Embodiment of this invention. It is explanatory drawing of a structure of the detection apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing of a surface emitting laser array. It is explanatory drawing of the incident angle of the incident light to a recording paper. It is explanatory drawing of the arrangement position of two light receivers. It is explanatory drawing of regular reflection light, surface diffuse reflection light, multiple diffuse reflection light, and internal diffuse reflection light. It is a functional block diagram of a control device. (A) is a diagram showing S1 and S2 relationship in a plurality of types of paper (the distribution) is a diagram showing the lambda _paper in (B) is more than one type of paper. (A) is a diagram showing a relationship (distribution) between S1 and λ _paper in a plurality of types of paper, and (B) is a diagram showing a relationship (distribution) between S2 and λ _paper in a plurality of types of paper, (C) is a diagram showing the relationship (distribution) between S2 / S1 and λ _paper in a plurality of types of paper. FIG. 10 is a flowchart for explaining an example of a sheet determination method. It is a figure which shows the correlation of the optical characteristic of a target object, and thermal conductivity. It is explanatory drawing of the structure of the detection apparatus which concerns on other embodiment of this invention. It is explanatory drawing of the arrangement position of four light receivers. It is explanatory drawing of the 1st modification of a detection apparatus. It is explanatory drawing of the pressure dependence of thermal conductivity. It is explanatory drawing of the 2nd modification of a detection apparatus. It is explanatory drawing of a structure of the conventional detection apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

<Image forming apparatus>
FIG. 1 shows a schematic configuration of a color printer 200 as an image forming apparatus according to an embodiment.

  The color printer 200 is a tandem multicolor printer that superimposes four colors (black, cyan, magenta, and yellow) to form a full-color image on a recording paper (recording medium). Two photosensitive drums (220a, 220b, 220c, 220d), four cleaning units (221a, 221b, 221c, 221d), four charging devices (222a, 222b, 222c, 222d), four developing rollers (223a, 223b) 223c, 223d), transfer belt 230, transfer roller 240, fixing device 250, paper feed tray 260, paper feed roller 261, registration roller pair 262, paper discharge roller 271, paper discharge tray 270, communication control device 280, control device. 290, the detection apparatus 100, and the like.

  The communication control device 280 controls bidirectional communication with a host device (for example, a computer) via a network or the like.

  FIG. 2 is a hardware configuration diagram showing the control device 290. The control device 290 includes a CPU (Central Processing Unit) 291, a ROM (Read Only Memory) 292 in which a program described by codes readable by the CPU 291 and various data used when executing the program are stored. A RAM (Random Access Memory) 293 that is a working memory, an AD conversion circuit 294 that converts analog data into digital data, an external connection I for transmitting various types of information to and from the communication control device 280 or the detection device 100 / F295 (Interface) has a bus line 296 such as an address bus and a data bus for electrically connecting the above-described components as shown in FIG. The control device 290 is electrically connected to the communication control device 280 and the detection device 100 via the external connection I / F 295. The control device 290 controls each unit in response to a request from the host device and sends image information from the host device to the optical scanning device 210.

  Returning to FIG. 1, the photosensitive drum 220a, the charging device 222a, the developing roller 223a, and the cleaning unit 221a are used as a set and form a black image (hereinafter also referred to as “K station” for convenience). Configure.

  The photosensitive drum 220b, the charging device 222b, the developing roller 223b, and the cleaning unit 221b are used as a set, and constitute an image forming station (hereinafter also referred to as “C station” for convenience) that forms a cyan image.

  The photosensitive drum 220c, the charging device 222c, the developing roller 223c, and the cleaning unit 221c are used as a set, and constitute an image forming station (hereinafter also referred to as “M station” for convenience) that forms a magenta image.

  The photosensitive drum 220d, the charging device 222d, the developing roller 223d, and the cleaning unit 221d are used as a set, and constitute an image forming station (hereinafter also referred to as “Y station” for convenience) that forms a yellow image.

  The photosensitive drums 220a to 220d, the cleaning units 221a to 221d, the charging devices 222a to 222d, and the developing rollers 223a to 223d described above have the same basic configuration except that the colors of the formed images are different. In the following description, when not distinguishing colors, alphabetic symbols are omitted as appropriate.

  Each of the photosensitive drums 220 has a photosensitive layer formed on the surface thereof. That is, the surface of each photoconductive drum is a surface to be scanned. Each photosensitive drum is rotated in the direction of the arrow in the plane of FIG. 1 by a rotating mechanism.

  Each charging device 222 uniformly charges the surface of the corresponding photosensitive drum.

  Based on the multicolor image information (black image information, cyan image information, magenta image information, yellow image information) from the host device, the optical scanning device 210 converts the light beam modulated for each color into the corresponding charged light beam. Irradiate each of the surfaces of the photosensitive drum 220. As a result, on the surface of each photoconductive drum, the charge disappears only in the portion irradiated with light, and a latent image corresponding to the image information is formed on the surface of each photoconductive drum. The latent image formed here moves in the direction of the corresponding developing roller 223 as the photosensitive drum rotates.

  As each developing roller 223 rotates, the toner from the corresponding toner cartridge is thinly and uniformly applied to the surface thereof. Then, when the toner on the surface of each developing roller comes into contact with the surface of the corresponding photosensitive drum 220, the toner moves only to the portion irradiated with light on the surface and adheres thereto. In other words, each developing roller causes toner to adhere to the latent image formed on the surface of the corresponding photosensitive drum so as to be visualized. Here, the image (toner image) formed by the adhesion of the toner moves in the direction of the transfer belt 230 as the photosensitive drum rotates.

  The yellow, magenta, cyan, and black toner images are sequentially transferred onto the transfer belt 230 at a predetermined timing and are superimposed to form a multicolor image.

  Recording paper is stored in the paper feed tray 260. A paper feed roller 261 is disposed on the downstream side of the paper feed tray 260 in the conveyance direction of the recording paper. The paper feed roller 261 takes out the recording paper one by one from the paper feed tray 260 and registers the pair of registration rollers. It is conveyed to 262. The registration roller pair 262 feeds the recording paper between the transfer belt 230 and the transfer roller 240 at a predetermined timing. As a result, the color image on the transfer belt 230 is transferred to the recording paper. The recording sheet transferred here is sent to the fixing device 250.

  In the fixing device 250, heat and pressure are applied to the recording paper, whereby the toner is fixed on the recording paper. The recording paper fixed here is sent to the paper discharge tray 270 via the paper discharge roller 271 and is sequentially stacked on the paper discharge tray 270.

  Each cleaning unit 221 removes toner (residual toner) remaining on the surface of the corresponding photosensitive drum 220. The surface of the photosensitive drum from which the residual toner is removed returns to the position facing the corresponding charging device 222 again.

  The color printer 200 has a detection device 100. In the present embodiment, the detection apparatus 100 is disposed in the vicinity of the paper feed tray 260 and is used to determine the recording paper stored in the paper feed tray 260. The arrangement of the detection device 100 is not particularly limited. For example, the intensity of reflected light and the temperature of one sheet separated in the sheet feed tray 260 can be detected.

  The detection device 100 performs measurement described later and outputs the detection result to the control device 290.

  The control device 290 as a processing unit determines the brand of the recording paper based on the detection result of the detection device 100 and stores it in the RAM 293 of the control device 290.

  The control device 290 functions as an adjustment device that adjusts the image forming conditions according to the determined brand of recording paper based on the output of the detection device 100. That is, when receiving a print job request from the user, the control device 290 as an adjustment device reads the recording paper brand stored in the RAM 293 and performs an adjustment process. For example, the optimum image forming conditions for the brand of the recording paper are determined from the image forming condition table storing the optimum image forming conditions (development conditions, transfer conditions, etc.) for each brand of the recording paper.

  Then, the control device 290 controls the developing device and the transfer device at each station according to the optimum image forming conditions. For example, the transfer voltage and the toner amount are controlled. Thereby, a high quality image is formed on the recording paper.

<Detection device>
The detection apparatus 100 according to the present embodiment makes it possible to determine an object based on the heat transfer characteristics of the object even when the plurality of objects have similar optical characteristics (for example, reflected light characteristics). As the reflected light characteristics, characteristics related to the light reflected by the object such as the intensity ratio of the reflected light in different directions and the intensity ratio of the reflected light having different polarization directions can be used in addition to the intensity of the reflected light. Moreover, as the heat transfer characteristics, in addition to the thermal conductivity described in the following embodiment, the temperature change rate in a certain period when the object is heated or cooled, the temperature after elapse of a certain time, etc. Properties related to heat transfer can be used. In addition, identification of the object includes not only identifying the brand of the recording paper described below, but also detecting the difference in the characteristics of the object and classifying based on the difference in the characteristics of the object. It is a waste.

  As illustrated in FIG. 3, the detection apparatus 100 includes a dark box 10, a light source 11, a collimator lens 12 (an example of an optical element), a light receiver 13 (an example of a first photodetector), and a polarization filter 14 (a polarized light). An example of an optical element), a light receiver 15 (an example of a second photodetector), two metal members 20 and 21 (an example of a heat conducting member), a heat source 22, a cooling source 23, and temperature detectors 24, 25, and 26. And a thickness detector 27 and the like.

  Here, in the XYZ three-dimensional orthogonal coordinate system, the direction orthogonal to the surface of the recording paper M is described as the Z-axis direction, and the plane parallel to the surface of the recording paper M is described as the XY plane. The dark box 10 is arranged on the + Z side of the recording paper.

  In the following, the light beam irradiated on the recording paper is referred to as “irradiation light”, the area irradiated with the irradiation light is referred to as “irradiation area”, and the center of the “irradiation area” is referred to as “illumination center”.

  Further, when light is incident on the boundary surface of the medium, a surface including the incident light ray and the normal of the boundary surface set at the incident point is referred to as an “incident surface”. When the incident light is composed of a plurality of light beams, there is an incident surface for each light beam. However, in the following, for convenience, the light incident surface incident on the illumination center O is referred to as an incident surface on the recording paper. . That is, the plane including the illumination center O and parallel to the XZ plane is the incident plane on the recording paper.

  In the description, the expressions S-polarized light and P-polarized light are used not only for the incident light on the recording paper M but also for the reflected light. For convenience of explanation, this is the incident surface of the light incident on the recording paper M. The polarization perpendicular to the incident surface is called S-polarized light, and the polarized light parallel to the incident surface is called P-polarized light.

  The dark box 10 is a box member that houses the light source 11, the collimating lens 12, the light receiver 13, the polarization filter 14, and the light receiver 15. An opening 101 is formed on the −Z side surface of the dark box 10. The dark box 10 is made of metal, for example, aluminum, and the surface thereof is subjected to black alumite treatment in order to reduce the influence of disturbance light and stray light.

The light source 11 has a semiconductor laser and emits laser light. In the present embodiment, the semiconductor laser is a vertical cavity surface emitting laser (VCSEL), and more specifically, as shown in FIG. 4, a plurality of light emitting elements formed on the same substrate. A surface emitting laser array (VCSEL array) 111 having a portion 112. As an example, FIG. 4 shows a surface emitting laser array 111 in which nine light emitting portions 112 are two-dimensionally arranged and each light emitting portion 112 is connected to an electrode pad 114 via a wiring member 113.
The light source 11 is turned on and off under the control of the control device 290.

  The light source 11 is arranged to irradiate the recording paper with S-polarized light (linearly polarized light in the first polarization direction).

  The collimating lens 12 is disposed on the optical path of the light beam emitted from the light source 11, and makes the light beam substantially parallel light.

  The light emitted from the light source 11 passes through the opening 101 provided in the dark box 10 and enters the recording paper from an incident angle inclined with respect to the normal direction of the surface of the recording paper M. Here, the incident angle θ (see FIG. 5) of the light incident on the recording paper is 80 °. In addition, illustration of the dark box 10 is abbreviate | omitted in FIG.

  The light receiver 13 and the light receiver 15 are arranged on the + X side of the illumination center O with respect to the X-axis direction. As shown in FIG. 6, the angle φ1 formed by the line connecting the illumination center O and the center of the light receiver 13 and the surface of the recording paper M is 170 °, and the illumination center O and the center of the light receiver 15 are formed. An angle φ2 formed by the connecting line and the surface of the recording paper M is 90 °.

  The polarizing filter 14 is for separating specific linearly polarized light, and is disposed between the illumination center O and the light receiver 15. The polarizing filter 14 is disposed so as to transmit P-polarized light (linearly polarized light in the second polarization direction) and shield S-polarized light. Instead of the polarizing filter 14, a polarizing beam splitter having an equivalent function may be used.

  The center of the light source 11, the illumination center O, and the centers of the light receivers 13 and 15 exist on substantially the same plane. That is, the light source 11, the collimating lens 12, the light receiver 13, the polarizing filter 14, and the light receiver 15 are disposed on the incident surface of the recording paper M. The light receiver 13 is disposed on the optical path of the light that is regularly reflected by the recording paper M. Further, the polarizing filter 14 and the light receiver 15 are arranged on the optical path of light diffusely reflected by the recording paper M.

  By the way, as shown in FIG. 7, the reflected light from the object when the object (recording paper M) is irradiated with light is reflected on the surface of the object and reflected inside the object. It can be divided into reflected light. In addition, the reflected light reflected on the surface of the object is further reflected regularly by the reflected light, reflected light reflected in the diffusion direction by one reflection, and unevenness on the surface of the object and reflected several times. It can be classified into reflected light reflected by. Hereinafter, for convenience, each reflected light is also referred to as “regular reflected light”, “surface diffuse reflected light”, and “multiple diffuse reflected light”. The reflected light reflected inside the object is also referred to as “internal diffuse reflected light”.

  That is, the reflected light from the object can be classified into regular reflected light, surface diffuse reflected light, multiple diffuse reflected light, and internal diffuse reflected light.

  When the object is general printing paper (recording paper M), the light incident on the inside of the object repeats reflection many times at the interface between the fibers and the pores in the object, so that the reflection direction is equal. The intensity distribution can be approximated to a Lambertian distribution.

  The polarization direction of the regular reflection light and the surface diffuse reflection light is the same as the polarization direction of the irradiation light. On the other hand, the multiple diffuse reflection light and the internal diffuse reflection light include a polarization component orthogonal to the polarization direction of the irradiation light. Here, the polarization direction is rotated by reflection on the recording paper when the irradiation light is reflected by a surface inclined in the rotation direction with respect to the traveling direction.

  In the present embodiment, the center of the light source 11, the illumination center O, and the centers of the light receivers 13 and 15 are on substantially the same plane. The polarization direction is rotated by the reflection when the irradiation light is reflected by the surface inclined in the direction of rotation with respect to the traveling direction, and is thus reflected once on the surface of the recording paper and sent to the light receivers 13 and 15. The direction of polarization of the reflected light is the same as the direction of polarization of the irradiation light. On the other hand, multiple diffuse reflected light reflected multiple times on the surface of the recording paper and internal diffuse reflected light reflected multiple times inside the recording paper are separated from the plane by the reflection path and then reflected again multiple times. Light reflected on a plane is also included. The polarization direction of such multiple diffuse reflection light and internal diffuse reflection light is different from the polarization direction of irradiation light. Therefore, the multiple diffuse reflection light and the internal diffuse reflection light directed to the light receivers 13 and 15 include a polarization component orthogonal to the polarization direction of the irradiation light.

  Therefore, the light receiving unit 13 receives reflected light in which regular reflection light, surface diffuse reflection light, multiple diffuse reflection light, and internal diffuse reflection light are mixed. However, at this light receiving position, the light amount of the surface diffuse reflection light, the multiple diffuse reflection light and the internal diffuse reflection light is very small compared to the light amount of the regular reflection light. Can be considered. That is, the light receiver 13 outputs an electrical signal (detection signal) corresponding to the amount of received light of the regular reflection light.

  Further, surface diffuse reflection light, multiple diffuse reflection light, and internal diffuse reflection light are incident on the polarizing filter 14. Here, since the polarization direction of the surface diffuse reflection light is S-polarized light that is the same as the polarization direction of the irradiation light, the surface diffuse reflection light is shielded (shielded) by the polarization filter 14. On the other hand, since the polarization directions of the multiple diffuse reflection light and the internal diffuse reflection light are rotated with respect to the polarization direction of the irradiation light, the multiple diffuse reflection light and the internal diffuse reflection light include S polarization and P polarization. Among them, the P-polarized light component is transmitted through the polarizing filter 14.

  Hereinafter, for the sake of convenience, the P-polarized component included in the multiple diffuse reflected light is also referred to as “P-polarized component of the multiple diffuse reflected light”. The S-polarized component included in the multiple diffuse reflected light is also referred to as “S-polarized component of the multiple diffuse reflected light”. Further, the P-polarized component included in the internal diffuse reflected light is also referred to as “P-polarized component of the internal diffuse reflected light”. Further, the S-polarized component contained in the internally diffuse reflected light is also referred to as “S-polarized component of the internally diffuse reflected light”.

  The light receiver 15 receives the “P-polarized component of the multiple diffuse reflected light” and the “P-polarized component of the internal diffuse reflected light” transmitted through the polarizing filter 14. In other words, the light receiver 13 outputs an electric signal (detection signal) corresponding to the received light amount that is the sum of the P-polarized component of the multiple diffuse reflected light and the P-polarized component of the internal diffuse reflected light.

  In the present embodiment, the light source 11 and the collimating lens 12 are examples of a light irradiation unit, and the light receiver 13, the polarizing filter 14, and the light receiver 15 are examples of a light detection unit. The light irradiation unit and the light detection unit constitute a reflected light measurement unit R.

  The metal member 20 is disposed on the + Z side of the recording paper M, and the metal member 21 is disposed on the −Z side of the recording paper M so as to face the metal member 20. That is, one end of the metal member 20 contacts the recording paper M at the time of measurement. The positions of the metal members 20 and 21 in the XY plane are substantially the same. The material of the metal members 20 and 21 is preferably a metal having high thermal conductivity, for example, copper (Cu).

  A heat source 22 for heating the metal member 20 is disposed in contact with the + Z side of the metal member 20, and a cooling source 23 for cooling the metal member 21 is disposed in contact with the −Z side of the metal member 21. As the heat source 22 and the cooling source 23, for example, a Peltier element that can be used as a heat source or a cooling source can be used. Further, a heat generating element such as a heat ray may be used as the heat source 22, and a heat radiating element such as a heat sink may be used as the cooling source 23.

  The temperature detector 24 is disposed at the + Z side end of the metal member 20, the temperature detector 25 is disposed at the −Z side end of the metal member 20, and the temperature detector 26 is disposed at the + Z side end of the metal member 21. Yes. Here, the temperature detector 24 and the temperature detector 25 are a set of temperature detectors that detect the temperature of the metal member 20 at a plurality of locations (two locations), and function as a first temperature detector. The temperature detector 25 and the temperature detector 26 are a set of temperature detectors that detect the temperature of the recording paper M at a plurality of locations (two locations), and function as a second temperature detector. As the temperature detectors 24, 25, and 26, for example, thermocouples can be used. Each of the temperature detectors 24, 25, and 26 outputs a signal corresponding to the temperature to the control device 290. The signal levels of the outputs from the temperature detectors are T1, T2, and T3, respectively.

  The thickness detector 27 is arranged side by side with the metal member 21 and measures the thickness of the object. As the thickness detector, for example, a displacement sensor that detects a displacement amount can be used. The thickness detector 27 outputs a signal corresponding to the thickness of the object to the control device 290. The signal level of the output from the thickness detector 27 is assumed to be x.

The metal members 20, 21, the heat source 22, the cooling source 23, the temperature detectors 24-26, and the thickness detector 27 operate as a thermal conductivity measuring unit H as an example of a heat transfer characteristic measuring unit. The thermal conductivity measuring unit H outputs the output from each detector to the control device 290, and the control device 290 calculates the thermal conductivity of the recording paper M. Equation (1) shows an equation for calculating the thermal conductivity.
[Formula (1)]

Here, λ _paper is the thermal conductivity of the recording paper M, λ _metal is the thermal conductivity of the metal member 20, ∂θ _metal is the temperature difference between the metal members 20 (temperature difference between the temperature detector 24 and the temperature detector 25), ∂θ _paper is the temperature difference of the recording paper (temperature difference between the temperature detector 25 and the temperature detector 26), ∂X _metal is the length of the metal member 20 (distance between the temperature detector 24 and the temperature detector 25), ∂ X _paper is the _paper thickness (distance between the temperature detector 25 and the temperature detector 26). That is, if the distance between the temperature detectors 24 and 25 (here, the length of the metal member 20) and the thermal conductivity of the metal member 20 are known, the temperatures T1, T2, T3 and the distance x are measured. Thus, the temperature gradient (∂θ _metal / ∂X _metal ) in the metal member 20 and the temperature gradient (∂θ _paper / ∂X _paper ) in the recording paper can be known, and the thermal conductivity of the recording paper can be obtained.

  The light receiver 13 and the light receiver 15 each output an electric signal (detection signal) corresponding to the amount of received light to the control device 290. Hereinafter, when the light source 11 is turned on, the output of the light receiver 13 is referred to as “S1”, and the output of the light receiver 15 is referred to as “S2”.

Moreover, the temperature detectors 24 to 26 output the detected temperatures to the control device 290, respectively. The position sensor outputs the detected position to the control device 290. The control device 290 calculates the equation (1) based on the temperature and position information, and calculates the thermal conductivity λ _paper of the recording paper M. In the detection apparatus 100 of the present embodiment, the optical characteristics and thermal conductivity of the recording paper can be measured simultaneously.

  Next, the functional configuration of the control device 290 will be described with reference to FIG. FIG. 8 is a functional block diagram of the control device 290. The control device 290 includes a reflected light measurement control unit 301, a thermal conductivity measurement control unit 302, a comparison unit 303, and a determination unit 304.

  The reflected light measurement control unit 301 is a module realized by the CPU 291 of the control device 290 executing a program read from the ROM 292. The reflected light measurement control unit 301 controls the light emission of the light source 11 and obtains the values of the outputs S1 and S2 from the electrical signals output from the light receivers 13 and 15.

  The thermal conductivity measurement control unit 302 is a module realized by executing a program read from the ROM 292 by the CPU 291 of the control device 290. The thermal conductivity measurement control unit 302 controls the operation of the heat source 22 and the cooling source 23, and based on the outputs T1, T2, T3 of the temperature detectors 24, 25, and 26 and the output x of the thickness detector 27, the paper The thermal conductivity λ paper is calculated.

The comparison unit 303 functions as a management unit that manages the recording sheet discrimination table. The comparison unit 303 as a management unit is a module realized by the ROM 292 of the control device 290 storing the recording sheet discrimination table and the CPU 291 of the control device 290 executing the program read from the ROM 292. Details of the recording sheet discrimination table will be described later.
The comparison unit 303 functions as means for comparing the input S1, S2, and λpaper with the recording sheet discrimination table. The comparison unit 303 as a comparison unit is a module realized by the CPU 291 of the control device 290 executing a program read from the ROM 292.

  The determination unit 304 is a module realized by the CPU 291 of the control device 290 of the control device 290 executing a program read from the ROM 292. The determination unit 304 reads the recording sheet determination table from the ROM 292 and determines the corresponding brand for the object to be determined based on the comparison result of the comparison unit 303.

  In FIG. 9A, the reflected light characteristics of a group consisting of 18 types of synthetic paper, 21 types of plain paper, and 14 types of gloss coated paper are measured using the detection device 300 having the above-described reflected light measurement unit R. The distribution map of the results is shown. The detection apparatus 300 is obtained by omitting the thermal conductivity measurement unit H from the detection apparatus 100 of the present embodiment as shown in FIG. Moreover, the result of having measured thermal conductivity about said group using the above-mentioned thermal conductivity measurement part H in FIG.9 (B) is shown. FIG. 9B is a one-dimensional graph, and the vertical axis has no meaning.

  In the distribution diagrams described in this specification, different points indicate different paper types even with the same symbol. As can be seen from FIG. 9A, in the synthetic paper, S1 (reflected light characteristic of specularly reflected light) and S2 (reflected light characteristic of P-polarized component of multiple diffuse reflected light and internal diffuse reflected light) are: There are similar ones to S1 and S2 in plain paper and gloss coated paper. In other words, the conventional detection apparatus that identifies the brand of the recording paper based only on the reflected light characteristic may output an incorrect type in the recording paper discrimination. In addition, as can be seen from FIG. 9B, even if only the thermal conductivity is measured, there are a plurality of recording papers showing similar thermal conductivity, so the paper type is determined only by measuring the thermal conductivity. It is difficult.

Therefore, the detection apparatus 100 of the present embodiment is used for a group consisting of five types of synthetic papers that are particularly difficult to discriminate among the 18 types of synthetic papers, 21 types of plain papers, and 14 types of gloss coated papers. Was used to measure the reflected light characteristics and the thermal conductivity characteristics. The results are shown in FIGS. 10 (A), B, and C. 10A is a distribution diagram of reflected light characteristics (S1) and thermal conductivity (λ _paper ), and FIG. 10B is a distribution of reflected light characteristics (S2) and thermal conductivity (λ _paper ). FIG. 10C is a distribution diagram of reflected light characteristics (S2 / S1) and thermal conductivity (λ _paper ). In either case, the measurement results for the synthetic paper can be largely separated from the measurement results for the recording papers of other brands, and it can be seen that the discrimination is facilitated.

The reason why the identification of the brand becomes easy by using the reflected light characteristic and the thermal conductivity characteristic will be discussed. S1 obtained by measuring the regular reflection light is considered to depend mainly on the surface state of the recording paper. Further, S2 obtained by measuring the polarization change component of the surface diffuse reflection light is considered to depend mainly on the density of the recording paper. On the other hand, it is considered that λ _paper obtained by measurement of thermal conductivity mainly depends on the material and density of the recording paper. Therefore, it is difficult to obtain information related to the material of the recording paper with the conventional detection device that identifies the brand of the recording paper based only on the reflected light characteristics. Further, by measuring only the thermal conductivity, not only information related to the surface state of the recording paper can be obtained but also information related to the material and density cannot be obtained individually. In this embodiment, since the reflected light characteristic and the thermal conductivity characteristic are used, information related to the surface state, density, and material of the object can be acquired effectively.

As described above, by combining the reflected light characteristics (here, S2 / S1) and the thermal conductivity (λ _paper ) information, the synthetic paper is separated from the plain paper or gloss coated paper in the distribution diagram. It is possible. Thereby, the possibility that the synthetic paper is mistakenly determined as plain paper or gloss coated paper is greatly reduced, and the discrimination accuracy of the detection apparatus 100 is improved.

  In the above, the improvement in discrimination accuracy between plain paper or gloss coated paper and synthetic paper, which are greatly different from each other, has been described. However, the present invention is not limited to this. For example, even if it is the same plain paper, there are not a few differences in the fibers constituting it, and information that cannot be obtained by optical measurement can be obtained by measuring the thermal conductivity.

  Moreover, in said embodiment, it is comprised so that the heat conductivity of the thickness direction of a target object may be measured. Thereby, the thermal conductivity of the whole thickness direction can be measured about the target object which consists of a several different material in the thickness direction like gloss coat paper, for example. On the other hand, when the thermal conductivity of the surface layer of the object is mainly measured, the thermal conductivity in the surface direction of the object (direction perpendicular to the thickness direction, direction along the surface of the object) is measured. It may be configured.

<Determination method of the object>
Next, an example of a recording sheet determination method based on the detection result of the detection apparatus 100 will be described with reference to FIG. FIG. 11 is a flowchart for explaining an example of a recording sheet discrimination method in the control device 290.

  As described above, the signal level in the output signal of the light receiver 13 is “S1”, and the signal level in the output signal of the light receiver 15 is “S2”.

The ROM of the control device 290 stores a recording sheet discrimination table regarding a plurality of brand recording sheets that the color printer 200 can handle. The recording sheet discrimination table includes S1 (intensity of reflected light), S2 (intensity of reflected light), and λ _paper (heat transfer characteristics) for each brand of a plurality of types of recording sheets measured in advance in the pre-shipment process. Contains a value. S1, S2, and λ _paper are discrimination information for discriminating the recording paper. Each of S1, S2, and λ _paper managed in the recording sheet discrimination table may be an average value when measured a plurality of times, or may include an upper limit value and a lower limit value when measured a plurality of times. FIG. 12 is an example of a graph showing the correlation between S1, S2, and λ _paper for each brand managed in the recording paper discrimination table. In FIG. 12, each area surrounded by a broken-line frame indicates a variation range of measured values for the same brand. Here, the description will be made using the S2 / S1 and λ _paper tables, but the recording paper discrimination table is a table composed of two parameters S1 or S2 and λ _paper , and three parameters S1, S2, and λ _paper. There may be.

The control device 290 performs processing for determining the brand of the recording paper (brand discrimination processing) when the color printer 200 is turned on or when the recording paper is supplied to the paper feed tray 260. In the brand identification process, the following steps are executed.
(1-1) The reflected light measurement control unit 301 causes the light source to emit light (STEP 1).
(1-2) The light receiver 13 and the light receiver 15 output S1 and S2 (electrical signals) (STEP 2).
(1-3) The reflected light measurement control unit 301 obtains values of S1 and S2 (reflected light characteristics), and further calculates S2 / S1 (reflected light characteristics) (STEP 3).
(2-1) The thermal conductivity measurement control unit 302 activates the heat source 22 and the cooling source 23 of the thermal conductivity measurement unit H (STEP 4).
(2-2) The temperature detectors 24, 25, and 26 of the thermal conductivity measuring unit H output temperatures T1, T2, and T3 (STEP 5).
(2-3) The thickness detector 27 of the thermal conductivity measuring unit H outputs the thickness x (STEP 6).
(2-4) The thermal conductivity measurement control unit 302 obtains λ _paper from T1, T2, T3, and t based on Expression (1) (STEP 7).
(3) The comparison unit 303 compares S1, S2, and λ _paper with the recording sheet discrimination table (STEP 8).
(4) The determination unit 304 determines the brand of the recording paper based on the comparison result of the comparison unit 303 (STEP 9).
(5) The determined brand of recording paper is stored in the RAM 293, and the brand discrimination process is terminated.

  Note that the order of (1-1) to (1-3) and (2-1) to (2-4) is not limited, and can be performed in parallel.

In (3) above, for example, if S2 / S1 and λ _paper are both within the range of the brand A as in the measured value “a” shown in FIG. . In addition, when one or both of the values of S2 / S1 and thermal conductivity are out of the range of the brand B as in the measured value “b”, there is no other similar paper type. The object may be determined to be the brand B which is the brand in the region closest to the measured value “b”. In addition, when the measured value spans the range of the brand C and the range of the brand D as in the measurement value “c”, for example, the difference between the average value and the measurement value of the brand C, and the brand D The difference between the average value and the measured value may be calculated, and the brand with the smaller calculation result may be determined. In addition, assuming that it is a stock C, recalculate the dispersion including the obtained measurement value, and assume that it is the stock D, recalculate the dispersion including the obtained measurement value, and re-calculate. You may choose the brand with the smaller calculated variation.

  As described above, in the detection apparatus 100 of the present embodiment, light is irradiated toward the surface of the object at an incident angle inclined with respect to the normal direction of the surface, and light reflected by the object is detected. It has a light detection unit, a thermal conductivity measurement unit that measures the thermal conductivity of the object, and a control device that discriminates the object based on the measurement result in the light detection unit and the measurement result in the thermal conductivity measurement unit. ing. By combining the measurement results of reflected light intensity and thermal conductivity, it is possible to determine with high accuracy even for objects that can obtain similar characteristics only by measuring reflected light or only measuring thermal conductivity. it can.

  In addition, the object discriminated by this embodiment is not limited to only synthetic paper, and the present invention can be used for objects having different thermal conductivities.

  In the above embodiment, the detection device may include another light receiver in addition to the light receivers 13 and 15. FIG. 13 shows a detection apparatus 100 </ b> A that further includes a light receiver 16, a polarization filter 17, and a light receiver 18 in addition to the configuration of the detection apparatus 100. In FIG. 13, wiring to the control device 290 and the control device 290 is omitted.

  The center of the light source 11, the illumination center O, the center of the light receiver 16, the center of the polarizing filter 17, and the center of the light receiver 18 exist on substantially the same plane.

  The light receiver 16 is disposed at a position for receiving surface diffuse reflection light, multiple diffuse reflection, and internal diffuse reflection light. Like the polarizing filter 14, the polarizing filter 17 is arranged to transmit P-polarized light. The light receiver 18 receives the light transmitted through the polarizing filter 17. The light transmitted through the polarizing filter 17 is P-polarized light of multiple diffuse reflection and internal diffuse reflection light.

  Here, the angle φ3 formed between the line connecting the illumination center O and the center of the light receiver 16 and the surface of the recording paper is 120 °, the line connecting the illumination center O and the center of the light receiver 18 and the recording paper The angle φ4 made with the surface is 150 ° (see FIG. 14).

  The light receiver 16 and the light receiver 18 each output an electrical signal (detection signal) corresponding to the amount of received light to the control device 290. Hereinafter, when the light source 11 is turned on, the output of the light receiver 16 is referred to as “S3”, and the output of the light receiver 18 is referred to as “S4”.

Also in this case, the brand determination process can be performed in the same manner as in the above embodiment. When the brand identification process is performed by the control device 290, a table that individually includes the values of S1, S2, S3, S4 and λ _paper may be used as the recording sheet discrimination table, or S3 / S1, S4 / S2, etc. _{Alternatively} , a table including a calculated value such as a ratio of detection values at each light receiver and a value of λ _paper may be used. When using a value obtained by calculating a detection value at each light receiver, the influence of disturbance light, stray light, or the like can be reduced.

  The light detected by the light receiver 16 and the light receiver 18 is reflected in a different direction from the light detected by the light receiver 13 and the light receiver 15, and includes different information. Therefore, the detection apparatus 100 includes at least one of the light receiver 16 and the light receiver 18, thereby improving the accuracy of object discrimination.

  As another method, it is also possible to narrow down the paper type roughly using S1 and S2, and to specify the brand of the recording paper using S3 and S4.

  Modification examples of the detection apparatus 100 described so far will be described below.

<Modification 1 of Detection Device>
A detection device 100B shown in FIG. 15 is obtained by adding a spring 28 to the detection device 100 to pressurize the metal member 20 in the direction of the recording paper M (−Z direction). In FIG. 15, wiring to the control device 290 and the control device 290 is omitted. The spring 28 is an example of a pressure member that applies pressure to the contact portion between the recording paper M and the metal member 20. Here, a spring 28 is connected to the heat source 22, and pressure is applied to the contact surface between the recording paper and the metal members 20, 21 when measuring the thermal conductivity of the recording paper.

The effect of pressurization will be described below. FIG. 16 shows a relationship between the pressure applied to the contact surface between the recording paper and the metal members 20 and 21 and the measured thermal conductivity (λ _paper ) when the thermal conductivity of plain paper is measured. As is clear from FIG. 16, when the pressure is small, the measured thermal conductivity value tends to be small. When the pressure is 500 g / cm ² or more, a constant thermal conductivity value is obtained. That is, it is considered that the heat conductivity value can be obtained more accurately by pressurization. Further, when no pressurization is performed, the pressure applied to the contact surface is different for each measurement, and there is a possibility that the measured value of thermal conductivity may vary. According to this modification, it is possible to reduce the variation in the thermal conductivity value due to the pressure variation at the time of measurement, and thus it is possible to perform a more accurate determination.

  In the above description, the pressure member is provided on the metal member 20 side, but may be provided on the metal member 21 side, or may be provided on both the metal member 20 and the metal member 21. Further, the pressurizing member may be any member that pressurizes the heat conducting member in the direction in which the object is arranged. In addition to a method using an elastic force like a spring, a method using gravity by a weight or the like is also used. be able to.

<Modification 2 of Detection Device>
A detection device 100C shown in FIG. 17 is obtained by adding a rubber sheet 29 as an example of an elastic member to the end portion (one end) of the detection device 100 on the side in contact with the recording paper M of the metal members 20 and 21. . In FIG. 17, wiring to the control device 290 and the control device 290 is omitted. The rubber sheet 29 is made of a material having a smaller elastic modulus than the metal members 20 and 21.

  For example, when the surface of the recording paper has large irregularities, if the adhesion to the metal members 20 and 21 is poor, an air layer is formed in the gap between the recording paper and the metal member, so that the thermal conductivity cannot be measured accurately. There is. According to this modification, the adhesion between the recording paper and the metal member can be improved, and the measurement accuracy of the thermal conductivity of the recording paper can be improved.

  The rubber sheet 29 is preferably a rubber sheet having a low elastic modulus (easily deformed) and having a thermal conductivity as high as possible. Moreover, it is preferable that the rubber sheet 29 is as thin as possible within a range in which adhesion can be maintained from the viewpoint of heat conduction.

In the above embodiment, the method of discriminating the object based on the reflected light measurement result and the thermal conductivity measurement result has been described. However, the discrimination is usually performed based on the reflected light measurement result, and sufficient discrimination accuracy is obtained. If not, the value of λ _paper may be used.

Moreover, in the said embodiment, although the temperature of the one end of the metal member 20 and the other end was measured, it is not limited to this, What is necessary is just to know the temperature difference between two points spaced apart by the predetermined distance in the metal member 20. Further, a temperature detector 24 ′ may be provided between the temperature detector 24 and the temperature detector 25, and λ _metal may be obtained from the temperature difference between the temperature detector 24 and the temperature detector 24 ′.

  Moreover, in the said embodiment, although the temperature of the relatively high temperature metal member was detected, you may detect the temperature of a relatively low temperature metal member. Moreover, in the said embodiment, you may arrange | position the heat source 22 and the cooling source 23 reversely.

  Moreover, in the said embodiment, although it was set as the structure by which a part of thermal conductivity measurement part H is arrange | positioned in the dark box 10, it is good also as a structure by which the thermal conductivity measurement part H is arrange | positioned outside the dark box 10. FIG.

  Although the method for deriving the thermal conductivity by the temperature gradient method has been described above, the method for detecting the thermal conductivity is not limited to the temperature gradient method, and other methods for measuring the thermal conductivity such as the hot wire method and the laser flash method can be used. It may be used.

  Moreover, in the said embodiment, although it was set as the structure provided with the light receiver 13 and the light receiver 15, it should just be provided with at least 1 light receiver.

  Moreover, in the said embodiment, a condensing lens may be provided in front of each light receiver (a light source side rather than each light receiver). In this case, signal level measurement variations can be reduced. If the surface of the recording paper tilts or rises from the normal measurement surface due to deflection of the recording paper or vibration during measurement, the light intensity distribution of the reflected light changes and the amount of received light changes. . Therefore, if the condenser lens is disposed in front of the light receiver, the amount of received light can be stabilized even when the light intensity distribution of the reflected light changes.

  In the above-described embodiment, the case where the control device 290 determines the brand of the recording paper has been described. However, it is not essential to determine the brand. For example, you may comprise so that an adjustment process may be directly performed from a measurement result.

  Moreover, although the said embodiment demonstrated the case where the control apparatus 290 had the function of a process part and an adjustment apparatus, the processing apparatus was provided in the detection apparatus 100, and at least 1 of the process in the control apparatus 290 in the case of brand identification processing is carried out. The unit may be performed by the processing apparatus. Further, at least a part of the processing in the control device 290 during the brand identification processing may be performed by a processing device provided in the host device.

  In the above embodiment, the case where the light irradiated to the object is S-polarized light is described. However, the present invention is not limited to this, and the light irradiated to the recording paper may be P-polarized light. However, in this case, a polarizing filter that transmits S-polarized light is used as the polarizing filter 14, and the light receiver 15 receives the S-polarized component contained in the internally reflected light.

  Moreover, although the said embodiment demonstrated the case where the light source 11 had a several light emission part, it is not limited to this, The light source 11 may have one light emission part.

  In the above embodiment, an edge emitting laser may be used instead of the surface emitting laser array.

  Moreover, although the said embodiment demonstrated the case where the detection apparatus 100 was arrange | positioned in the vicinity of the paper feed tray 260, it is not limited to this. For example, the detection device 100 may be disposed in the vicinity of the recording paper conveyance path. Further, the detection apparatus 100 may be configured separately from the color printer 200.

  In the above embodiment, the case where there is one paper feed tray has been described. However, the present invention is not limited to this, and a plurality of paper feed trays may be provided. A detection device 100 may be provided for each paper feed tray.

  In the above embodiment, the case of the color printer 200 as the image forming apparatus has been described. However, the present invention is not limited to this. For example, an optical plotter or a digital copying apparatus may be used.

  In the above embodiment, the case where the image forming apparatus has four photosensitive drums has been described. However, the present invention is not limited to this.

  The detection apparatus 100 can also be applied to an image forming apparatus that forms an image by spraying ink on recording paper.

  Further, in the above embodiment, the recording paper discrimination by the detection apparatus 100 has been described, but the object is not limited to the recording paper. For example, the present invention can be applied to various objects such as a metal thin film and a resin sheet.

<Summary of Embodiment Examples, Actions, and Effects of the Present Invention>
The present invention can be implemented in the following modes.
<< First Embodiment >>
The detection device 100 includes a light source 11, a light detection unit (a light receiver 13, a polarization filter 14, and a light receiver 15) that detects reflected light of light emitted from the light source and reflected by an object (recording paper M), and a target. Heat transfer characteristic measurement unit (thermal conductivity measurement unit H) that measures the temperature of the object, and reflected light characteristics of the object obtained from the output of the light detection unit and the transfer of the object obtained from the output of the heat transfer characteristic measurement unit And a discriminator 304 that discriminates an object based on the thermal characteristics.
Here, as the reflected light characteristics, characteristics related to the light reflected by the object such as the intensity ratio of the reflected light in different directions and the intensity ratio of the reflected light having different polarization directions can be used in addition to the intensity of the reflected light. . As the heat transfer characteristics, in addition to the thermal conductivity, characteristics related to heat transfer in the object, such as a temperature change rate during a certain period when the object is heated or cooled, a temperature after a certain time has elapsed, and the like can be used. .

Conventionally, a brand of recording paper has been estimated by detecting regular reflection light, surface diffuse reflection light, and internal diffuse reflection light (Patent Document 1). On the other hand, in recent years, there are various types of recording paper such as coated paper, plastic sheet, embossed paper, synthetic paper made from synthetic resin, as well as plain paper, gloss coated paper, matte coated paper, and art coated paper. It has increased. Thereby, in the measurement by the conventional technique, reflected light characteristics similar to those of other recording papers are obtained on some recording papers, and it may be difficult to distinguish these.
As an example of the case where the discrimination is difficult, there is discrimination between plain paper or gloss coated paper and synthetic paper. Synthetic paper is “paper” manufactured using synthetic resin as a main raw material, and has a different material from general paper using wood pulp as a main raw material. On the other hand, the properties of general paper are given to synthetic paper. As will be described in detail later, some synthetic paper has optical properties similar to those of plain paper or gloss coated paper.
Since the raw material of synthetic paper is a resin, there is a possibility that the image quality is deteriorated due to thermal shrinkage due to printing at a high temperature (for example, toner fixing under a high temperature condition). Therefore, it is required to improve the discrimination accuracy between plain paper and gloss coated paper.

  In this embodiment, the object is discriminated based on the reflected light characteristic and the heat transfer characteristic as information related to the surface state, density, and material of the object. Since the heat transfer characteristic is used for the discrimination of the object, it is possible to improve the discrimination accuracy of the object having similar optical characteristics.

<< Second Embodiment >>
The detection apparatus 100 according to the present aspect has a reflected light characteristic (S1, S2, S2 / S1) of the object and a heat transfer characteristic (λ _paper ) of the object for a plurality of types of objects (recording _paper ), respectively. The management part (comparison part 303) which manages the discrimination | determination information to show, and the reflected light characteristic and heat-transfer characteristic measurement part (heat) of the target object obtained from the output of a photon detection part (light receiver 13, polarizing filter 14, and light receiver 15) A comparison unit 303 for comparing the heat transfer characteristics of the object obtained from the output of the conductivity measurement unit H) with the discrimination information, and the discrimination unit 304 discriminates the object based on the comparison result of the comparison unit. .
In this aspect, the discrimination information, which is information related to the surface state, density, and material of the object, is compared with the reflected light characteristics and heat transfer characteristics of the object obtained by measurement, and the object is based on the comparison result. Is determined. Since the heat transfer characteristic is used for the discrimination of the object, it is possible to improve the discrimination accuracy of the object having similar optical characteristics.

<< Third Embodiment >>
In the detection apparatus 100 according to this aspect, the heat transfer characteristic is the thermal conductivity in the thickness direction of the object (recording paper M).
For example, when recording paper made of a plurality of materials different in the thickness direction, such as gloss coated paper, is used as the heat transfer characteristic, heat conductivity considering the plurality of materials included in the object is used. As a result, it is possible to improve the discrimination accuracy of the object.

<< Fourth Embodiment >>
In the detection apparatus 100 according to this aspect, the heat transfer characteristic measurement unit (thermal conductivity measurement unit H) includes a heat conduction member (metal members 20 and 21) whose one end is in contact with the object (recording paper M), and heat conduction. A heat source 22 that heats the member, a first temperature detector (temperature detectors 24 and 25) that detects the temperature of the heat conducting member at a plurality of locations, and a second temperature detection that detects the temperature of the object at a plurality of locations. (Temperature detectors 25 and 26).
For discrimination of an object, thermal conductivity can be used as a heat transfer characteristic. In this aspect, information necessary for calculating the thermal conductivity is obtained by detecting the temperatures of the heat conducting member and the object at a plurality of locations.

<< Fifth Embodiment >>
The detection apparatus 100B according to this aspect includes a pressurizing member (spring 28) for applying pressure to a contact portion between the object (recording paper M) and the heat conducting member (metal members 20, 21).
According to this aspect, since the variation in the heat transfer characteristic value due to the pressure variation at the time of measurement can be reduced, it is possible to perform the determination with higher accuracy.

<< Sixth Embodiment >>
The detection device 100C according to this aspect includes an elastic member (rubber sheet 29) having an elastic modulus smaller than that of the heat conductive member at one end of the heat conductive member (metal members 20, 21).
For example, when there is large unevenness on the surface of the object (recording paper M), an air layer is formed in the gap between the object and the heat conduction member when the adhesion to the heat conduction member is poor. Therefore, there is a possibility that the thermal conductivity that is one cannot be measured accurately. According to this aspect, the adhesion between the object and the heat conducting member can be improved, and the measurement accuracy of the heat conductivity of the object can be improved.

<< Seventh Embodiment >>
The detection apparatus 100 according to this aspect includes a light source 11 and has an incident angle (incident angle θ) inclined with respect to the normal direction of the surface toward the surface of the object (recording paper M) and having a first polarization direction. An irradiation unit (light source 11 and collimating lens 12) that irradiates linearly polarized light (S-polarized light) is provided, and a light detection unit (light receiver 13, polarization filter 14, and light receiver 15) is emitted from the irradiation unit and regularly reflected by an object. A first light detector (light receiver 13) disposed on the optical path of the light to be transmitted, and the first polarized light disposed on the optical path of the light diffusely reflected by the object within the incident surface of the object A polarization optical element (polarization filter 14) that separates linearly polarized light (P-polarized light) in the second polarization direction orthogonal to the direction, and an optical path of light of linearly polarized light in the second polarization direction separated by the polarization optical element A second photodetector (receiver 15) disposed.
The reflected light from the object when the object is irradiated with light should be divided into reflected light reflected from the surface of the object and reflected light reflected from the inside of the object (internal diffuse reflected light). Can do. In addition, the reflected light reflected on the surface of the object is further reflected regularly reflected light (regular reflected light), reflected light reflected in the diffusion direction by one reflection (surface diffuse reflected light), target It can be classified into reflected light (multiple diffuse reflected light) reflected multiple times by the unevenness of the object surface and reflected in the diffusion direction.
The polarization directions of the regular reflection light and the surface diffuse reflection light are the same as the polarization direction (first polarization direction) of the irradiation light irradiated from the irradiation unit. On the other hand, the multiple diffuse reflection light and the internal diffuse reflection light include a polarization component (linear polarization in the second polarization direction) orthogonal to the polarization direction of the irradiation light.
In other words, in the detection device, the regular reflection light is detected by the first photodetector, and the internal diffuse reflection light and the multiple diffuse reflection light are detected by the second photodetector.

<< Eighth Embodiment >>
In the detection apparatus 100 according to this aspect, the object is a recording medium.
According to this aspect, it is possible to improve the discrimination accuracy of recording media having similar optical characteristics.

<< Ninth Embodiment >>
The present embodiment is an image forming apparatus (color printer 200) including the detection apparatus 100.
Some synthetic papers manufactured using synthetic resin as a main raw material have optical properties similar to those of plain paper or gloss coated paper. Since the raw material of synthetic paper is a resin, there is a possibility that the image quality is deteriorated due to thermal shrinkage due to printing at a high temperature (for example, toner fixing under a high temperature condition).
According to this aspect, since the heat transfer characteristic is used for discrimination of the object, it is possible to improve the discrimination accuracy of the object having similar optical characteristics. In addition, it is possible to determine the optimum image forming conditions (development conditions, transfer conditions, etc.) for the identified object and to control the image forming conditions (transfer voltage, toner amount, etc.), so that a high quality image can be obtained. Can be formed.

<< Tenth Embodiment >>
The image forming apparatus (color printer 200) according to this aspect includes an adjusting device (control device 290) that adjusts image forming conditions based on the output of the detection device 100.
Some synthetic papers manufactured using synthetic resin as a main raw material have optical properties similar to those of plain paper or gloss coated paper. Since the raw material of synthetic paper is a resin, there is a possibility that the image quality is deteriorated due to thermal shrinkage due to printing at a high temperature (for example, toner fixing under a high temperature condition).
According to this aspect, since the heat transfer characteristic is used for discrimination of the object, it is possible to improve the discrimination accuracy of the object having similar optical characteristics. In addition, it is possible to determine the optimum image forming conditions (development conditions, transfer conditions, etc.) for the identified object and to control the image forming conditions (transfer voltage, toner amount, etc.), so that a high quality image can be obtained. Can be formed.

<< Eleventh Embodiment >>
In the image forming apparatus (color printer 200) according to this aspect, the adjustment device (control device 290) determines the type of the object (brand of the recording paper M) based on the output of the detection device 100, and the determined type. The image forming conditions are adjusted according to the above.
Some synthetic papers manufactured using synthetic resin as a main raw material have optical properties similar to those of plain paper or gloss coated paper. Since the raw material of synthetic paper is a resin, there is a possibility that the image quality is deteriorated due to thermal shrinkage due to printing at a high temperature (for example, toner fixing under a high temperature condition).
According to this aspect, since the heat transfer characteristic is used for discrimination of the object, it is possible to improve the discrimination accuracy of the object having similar optical characteristics. In addition, it is possible to determine the optimum image forming conditions (development conditions, transfer conditions, etc.) for the identified object and to control the image forming conditions (transfer voltage, toner amount, etc.), so that a high quality image can be obtained. Can be formed.

DESCRIPTION OF SYMBOLS 10 ... Dark box, 11 ... Light source, 12 ... Collimating lens (optical element), 13 ... Light receiver (1st photodetector), 14 ... Polarization filter (polarization optical element), 15 ... Light receiver (2nd light detection) ), 16 ... light receiver, 17 ... polarizing filter, 18 ... light receiver, 20 ... metal member (heat conducting member), 21 ... metal member (heat conducting member), 22 ... heat source, 23 ... cooling source, 24 ... temperature. Detector 25 ... Temperature detector 26 ... Temperature detector 27 ... Thickness detector 28 ... Spring (pressurizing member) 29 ... Rubber sheet (elastic member) 200 ... Color printer 210 ... Light scanning Devices 220a, 220b, 220c, 220d ... photosensitive drums, 221a, 221b, 221c, 221d ... cleaning units, 222a, 222b, 222c, 222d ... charging devices, 223a, 223b, 223c, 22 d: Development roller, 230: Transfer belt, 240: Transfer roller, 250: Fixing device, 290 ... Control device, 301: Reflected light measurement control unit, 302 ... Thermal conductivity measurement control unit, 303 ... Comparison unit (management unit) , 304: discriminating unit, 100: detecting device, M: recording paper, R: reflected light measuring unit, H: thermal conductivity measuring unit.

JP 2012-127937 A

Claims (11)

A light source;
A light detection unit that detects reflected light of light emitted from the light source and reflected by an object;
A heat transfer characteristic measurement unit for measuring the temperature of the object;
A discriminating unit for discriminating the object based on the reflected light characteristic of the object obtained from the output of the light detection unit and the heat transfer characteristic of the object obtained from the output of the heat transfer characteristic measuring unit; Detection device. For a plurality of types of objects, a management unit that manages discrimination information indicating the reflected light characteristics of the objects and the heat transfer characteristics of the objects,
A comparison unit that compares the reflected light characteristic of the object obtained from the output of the light detection unit and the heat transfer characteristic of the object obtained from the output of the heat transfer characteristic measurement unit with the discrimination information; ,
The detection device according to claim 1, wherein the determination unit determines the object based on a comparison result of the comparison unit.   The detection device according to claim 1, wherein the heat transfer characteristic is a thermal conductivity in a thickness direction of the object.   The heat transfer characteristic measurement unit includes a heat conduction member having one end in contact with the object, a heat source that heats the heat conduction member, and a first temperature detection unit that detects temperatures of the heat conduction member at a plurality of locations. And a second temperature detector that detects the temperature of the object at a plurality of locations.   The detection device according to claim 4, further comprising a pressure member for applying pressure to a contact portion between the object and the heat conducting member.   The detection device according to claim 4, wherein an elastic member having an elastic modulus smaller than that of the heat conductive member is provided at the one end of the heat conductive member. An irradiation unit that includes the light source and irradiates the linearly polarized light in the first polarization direction at an incident angle inclined with respect to the normal direction of the surface toward the surface of the object;
The light detection unit is
A first photodetector disposed on an optical path of light emitted from the irradiation unit and regularly reflected by the object;
A polarizing optical element that is disposed on an optical path of light diffusely reflected by the object within the incident surface of the object and separates linearly polarized light in a second polarization direction orthogonal to the first polarization direction;
A detection device according to claim 1, further comprising: a second photodetector arranged on an optical path of linearly polarized light having a second polarization direction separated by the polarization optical element. .   The detection apparatus according to claim 1, wherein the object is a recording medium.   An image forming apparatus comprising the detection device according to claim 1.   The image forming apparatus according to claim 9, further comprising an adjusting device that adjusts an image forming condition based on an output of the detecting device.   The image forming apparatus according to claim 10, wherein the adjustment device determines a type of the object based on an output of the detection device, and adjusts an image forming condition according to the determined type.

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