JP2019095486A - Recording material discriminating apparatus and method for controlling recording material discriminating apparatus - Google Patents

Abstract

To provide a recording material discrimination device and a control method of a recording material discrimination device capable of suppressing the deterioration of the life of a sensor while suppressing the deterioration in the discrimination accuracy of the kind of a recording material and the recording material discrimination device and the control method of the recording material discrimination device capable of shortening the time required for discriminating the kind of recording material while suppressing the deterioration in the discrimination accuracy of the kind of recording material.SOLUTION: The recording material discriminating device includes a recording material conveying part 10 for conveying a recording material, a plurality of sensors for outputting information on physical properties of recording materials detected in different manners, and a control part 40 for discriminating the kind of a first recording material to be conveyed based on outputs of the plurality of sensors when conveying a plurality of recording materials by the recording material conveying part 10 one by one. Based on the discrimination result of the first recording material, the control unit 40 selects a sensor to be used preferentially from among the plurality of sensors in order to discriminate the types of the second and subsequent recording materials to be conveyed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a recording material determination device and a control method of the recording material determination device. More particularly, the present invention relates to a recording material determination apparatus for determining the type of recording material and a control method of the recording material determination apparatus.

  The electrophotographic image forming apparatus includes an MFP (Multi Function Peripheral), a facsimile machine, a copier, a printer, etc. having a scanner function, a facsimile function, a copying function, a function as a printer, a data communication function, and a server function. is there.

  In the conventional image forming apparatus, when the recording material is supplied to the cassette of the image forming apparatus, the user sets the type of recording material based on the basis weight of the recording material through the operation panel or PC (Personal Computer). I needed it. The image forming apparatus forms a high quality image by selecting a transport speed and a fixing temperature that are optimal for the set type of recording material. However, due to the difficulty and annoyance of the method of setting the type of recording material, the type of recording material may not be set accurately, resulting in paper jamming or deterioration of the formed image.

  Therefore, a recording material determination apparatus (media for reducing the burden on the user who sets the type of recording material by automatically detecting the physical properties of the recording material to be printed and determining the type of the recording material based thereon A sensor is proposed in the following Patent Document 1 and the like.

  In Patent Document 1 below, the type of the first recording material is determined, and image formation is performed under the image forming conditions according to the determined type of recording material, and the type of recording material for the second and subsequent sheets is determined. There is disclosed a technique for forming an image without discriminating the image.

U.S. Pat. No. 7,783,211

  In recent years, the types of recording materials used in image forming apparatuses are diverse. In particular, with regard to backing paper and label paper, the type can not be detected using a conventional media sensor. In order to improve the determination accuracy of the type of recording material, the image forming apparatus is a plurality of sensors suitable for detecting each type of recording material, and a plurality of sensors which detect physical properties of the recording material by different methods. Need to be loaded. The image forming apparatus operates a plurality of sensors every time a recording material is fed, or performs a process of determining a sensor to be preferentially used in determining the type of recording material from among the plurality of sensors. There is a need to. For this reason, there has been a problem that the life of the sensor is reduced by operating a plurality of sensors each time a recording material is fed, and a problem is that it takes time to determine the type of recording material.

  Here, according to the technology of Patent Document 1, it is possible to suppress the decrease in the life of the sensor by performing image formation without determining the type of the recording material for the second and subsequent sheets, and the type of the recording material The time of discrimination of However, in the technique of Patent Document 1, since the type of the recording material of the second and subsequent sheets is not determined, when the type of the recording material of the second and subsequent sheets is different from the type of the recording material of the first sheet, This has resulted in a reduction in the type of discrimination accuracy. As a result, the second and subsequent recording materials can not be printed under the optimum printing conditions, and the image quality is degraded.

  The present invention is to solve the above-mentioned problems, and an object thereof is a recording material discriminating apparatus and a recording material capable of suppressing the deterioration of the life of the sensor while suppressing the deterioration of the discrimination accuracy of the type of the recording material. It is providing the control method of a discrimination device.

  Another object of the present invention is to provide a recording material discrimination device and a control method of the recording material discrimination device capable of shortening the time required for discrimination of the type of recording material while suppressing a decrease in the accuracy of discrimination of the type of recording material. It is to provide.

  According to one aspect of the present invention, there is provided a recording material discriminating apparatus comprising: conveying means for conveying a recording material; a plurality of sensors for outputting information on physical properties of the recording material detected by different methods; First discrimination means for discriminating the type of the first recording material transported by the transport means based on the outputs of the plurality of sensors when transporting the recording material one by one, and the first discrimination means Among the plurality of sensors, among the plurality of sensors, a sensor that is preferentially used to determine the type of the second and subsequent recording materials conveyed by the conveyance unit on the basis of the result of the determination of the type of the first recording material according to And selection means for selecting from.

  Preferably, the recording material discriminating apparatus further comprises a printing means for printing on the recording material conveyed by the conveying means, and the conveying means records at the printing position by the printing means according to the timing of printing by the printing means. The detection position of each of the plurality of sensors is on the upstream side of the registration roller along the conveyance path of the recording material.

  In the recording material discriminating apparatus, preferably, the types of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selecting unit and the first recording material discriminated by the first discriminating unit Identity determination means for determining identity with types, and types of recording materials for the second and subsequent sheets determined based on the output of the sensor selected by the selection means, and one sheet determined by the first determination means And a second determination unit configured to determine the types of the second and subsequent recording materials based on the outputs of the plurality of sensors when it is determined by the identity determination unit that the type of recording material is different from that of the eyes. Prepare.

  Preferably, in the recording material discriminating apparatus, the transport means is configured to discriminate the type of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selecting means and the first sheet discriminated by the first discrimination means. The conveyance of the second and subsequent recording materials is performed until the second discrimination unit determines the types of the second and subsequent recording materials when the identity determination unit determines that there is a difference between the types of recording materials. Reduce the speed.

  Preferably, in the recording material discriminating apparatus, the printing unit is a type of the recording material of the second and subsequent sheets discriminated based on the output of the sensor selected by the selecting unit, and the first sheet discriminated by the first discriminating unit If it is determined by the identity determination unit that the type of recording material is different from the type of recording material, printing on the second and subsequent recording materials is performed until the type of the second and subsequent recording materials is determined by the second determination unit. Not start.

  Preferably, in the recording material discriminating apparatus, the plurality of sensors include an optical sensor which outputs information on the transmittance of light passing through the recording material, and the second discriminating means comprises at least two sheets based on the output of the optical sensor. Determine the type of recording material after the eye.

  Preferably, in the recording material discriminating apparatus, the plurality of sensors are an optical sensor that outputs information on the transmittance of light transmitted through the recording material, and an ultrasonic sensor that outputs information on the transmittance of ultrasonic waves transmitted through the recording material. And the first determination unit determines one sheet based on the output of the optical sensor when the transmittance of the first recording material indicated by the information output by the optical sensor is larger than the first threshold. The physical properties of the recording material of the eye are specified, and the transmittance of the first recording material indicated by the information output by the optical sensor is within a range smaller than the first threshold and larger than the second threshold. An identifying unit for identifying the physical properties of the first recording material based on the output of the ultrasonic sensor, and a first recording material based on a state of deviation of the physical properties identified by the identifying unit from the reference value Means for determining the type of No.

  Preferably, in the recording material discriminating apparatus, the plurality of sensors further include a paper thickness sensor for outputting information on the displacement amount of the displacement member when the recording material passes the detection position of the displacement member, and the identification means is an optical sensor If the transmittance of the first recording material indicated by the information output in the above is smaller than the second threshold, the physical properties of the first recording material are specified based on the output of the paper thickness sensor.

  Preferably, in the recording material discriminating apparatus, the selecting means selects, as the sensor to be preferentially used, the sensor used by the specifying means to specify the physical properties of the first recording material.

  Preferably, in the recording material discriminating apparatus, the first discriminating means has two axes indicating the transmittance of the first recording material indicated by the information outputted by the optical sensor and the physical properties specified by the specifying means. The deviation determining means further includes a plotting means for plotting on the coordinates, and the deviation determining means is from the reference curve on the two-axis coordinates showing the change of the reference value according to the change of the transmittance of the recording material of the points plotted by the plotting means. The type of recording material is determined based on the state of deviation.

  Preferably, in the recording material discriminating apparatus, the recording material is accommodated in the storage unit, and the recording material can not be replenished from the outside of the recording material discriminating apparatus. The first recording material is conveyed by the conveyance means after the first recording material is switched from the open state to the closed state. The second and subsequent recording materials are conveyed by the conveyance means until the storage portion is switched to the open state again after the conveyance of the first recording material.

  According to another aspect of the present invention, there is provided a control method of a recording material discriminating apparatus comprising: recording means for conveying a recording material; and recordings each of a plurality of sensors for outputting information on physical properties of the recording material detected by different methods. It is a control method of the material discrimination device, and when the plurality of recording materials are conveyed one by one by the conveyance unit, the type of the first recording material conveyed by the conveyance unit is the output of the plurality of sensors. The type of the second and subsequent recording materials conveyed by the conveyance means is discriminated based on the first discrimination step of discrimination based on the first discrimination step and the discrimination result of the type of the first recording material in the first discrimination step And a selection step of selecting a sensor to be preferentially used in selecting from among a plurality of sensors.

  According to the present invention, it is possible to provide a recording material discrimination device and a control method of the recording material discrimination device capable of suppressing the decrease in the life of the sensor while suppressing the decrease in the accuracy of determination of the type of recording material. Further, it is possible to provide a recording material discrimination device and a control method of the recording material discrimination device capable of shortening the time required for discrimination of the type of recording material while suppressing a decrease in the accuracy of discrimination of the type of recording material.

FIG. 1 is a cross-sectional view schematically showing a configuration of an image forming apparatus 1 according to an embodiment of the present invention. It is a figure which shows the structure of one part of the optical sensor 51 in one embodiment of this invention, the ultrasonic sensor 52, and the paper thickness sensor 53, Comprising: When it cuts in xz plane in the 1st position of y-axis direction FIG. It is a figure which shows the structure of one part of the optical sensor 51 in one embodiment of this invention, the ultrasonic sensor 52, and the paper thickness sensor 53, Comprising: When it cuts in xz plane in the 2nd position of y-axis direction FIG. FIG. 17 is a view showing a configuration of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 in the embodiment of the present invention, in which the vicinity of the substrate 512 is in the direction from the positive to negative of the x axis. It is a figure at the time of seeing. It is a figure which shows the structure of a part of optical sensor 51 in the embodiment of the present invention, ultrasonic sensor 52, and paper thickness sensor 53, and saw near the substrate 512 in the direction from positive to negative of z axis FIG. FIG. 8 is a view showing a configuration of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 in the embodiment of the present invention, and a perspective view of the vicinity of the resist roller 14. FIG. 6 is a view showing a method of detecting the basis weight of the recording material M using the optical sensor 51 according to an embodiment of the present invention. It is a figure which shows various printing patterns of a backing paper typically. FIG. 7 is a view showing a method of detecting the basis weight of the recording material M using the ultrasonic sensor 52 according to an embodiment of the present invention. FIG. 6 is a view showing a method of detecting the basis weight of the recording material M using the paper thickness sensor 53 in the embodiment of the present invention. It is a figure which shows typically the information which the sensor part 54 outputs in one embodiment of this invention. It is a graph which shows the relationship between the transmittance | permeability of the light which permeate | transmits the recording material detected using the optical sensor 51 in one embodiment of this invention, and the actual basis weight of a recording material. It is a figure which shows the relationship between the voltage value which the ultrasonic sensor 52 in one embodiment of this invention outputs, and the actual basis weight of a recording material. 5 is a graph showing a relationship between a basis weight of a recording material detected using a paper thickness sensor 53 according to an embodiment of the present invention and an actual basis weight of the recording material. FIG. 6 is a view showing detection accuracy of each of an optical sensor 51, an ultrasonic sensor 52, and a paper thickness sensor 53 for various recording materials. FIG. 6 is a view showing a combination of the transmittance of the recording material and the sensor used for basis weight detection in the embodiment of the present invention. FIG. 6 is a diagram showing a method of determining the type of recording material in the embodiment of the present invention. It is a figure which shows typically the setting table in one embodiment of this invention. 6 is a first part of a flowchart showing the operation of the image forming apparatus 1 in an embodiment of the present invention. 10 is a second part of a flowchart showing the operation of the image forming apparatus 1 in an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

  In the following embodiments, the case where the recording material determination device is mounted on the image forming apparatus will be described. Examples of the image forming apparatus include an MFP, a printer, a copying machine, and a facsimile. In addition, the recording material determination device may be mounted on an apparatus other than an image forming apparatus such as a recording material storage device or a post-processing device.

  In the drawings, the width direction when the image forming apparatus 1 is viewed from the front is the x-axis direction, the depth direction is the y-axis direction, and the height direction is the z-axis. Each of the x-axis, y-axis and z-axis is orthogonal to one another.

  [Configuration of image forming apparatus]

  FIG. 1 is a cross-sectional view schematically showing a configuration of an image forming apparatus 1 according to an embodiment of the present invention.

  Referring to FIG. 1, the image forming apparatus 1 (an example of a recording material discriminating apparatus) according to the present embodiment discriminates the type of the recording material, and the printing conditions according to the type of the recording material discriminated are: Print on the screen. The image forming apparatus 1 includes a recording material conveyance unit 10 (an example of a conveyance unit), a paper feed tray 11 (an example of a storage unit), a toner image formation unit 20 (an example of a printing unit), a fixing device 21, and a power supply. It mainly comprises a unit 22, an operation input unit 23, a control unit 40, an optical sensor 51, an ultrasonic sensor 52, a paper thickness sensor 53 (an example of a plurality of sensors), an open / close sensor 56 and the like.

  The paper feed tray 11 stacks and accommodates the recording material M for forming an image. The sheet feeding tray 11 can be switched between an open state in which the recording material can be replenished from the outside of the image forming apparatus 1 and a closed state in which the recording material can not be replenished from the outside of the image forming apparatus 1. The paper feed tray 11 may be plural.

  The recording material conveyance unit 10 conveys the recording material M along the conveyance path TR. The recording material conveyance unit 10 includes a sheet feed roller 12, a conveyance roller 13, a registration roller 14, a sheet discharge roller 15, and a sheet discharge tray 16. The paper feed roller 12 is provided between the paper feed tray 11 and the transport path TR. The transport roller 13 and the registration roller 14 are provided along the transport path TR. The resist roller 14 includes a metal roller 141 and a rubber roller 142. The discharge roller 15 is provided at the most downstream part of the transport path TR. The discharge tray 16 is provided at the top of the image forming apparatus main body 1a.

  The toner image forming unit 20 synthesizes four color images of Y (yellow), M (magenta), C (cyan) and K (black) in a so-called tandem system, and at the printing position ST, the recording material conveyance unit 10 Forms a toner image on the recording material M conveyed by The toner image forming unit 20 includes an intermediate transfer belt 20a. The toner image forming unit 20 also includes a photosensitive drum, a charging roller, an exposure device, a developing device, a primary transfer roller, a secondary transfer roller, and the like.

  The fixing device 21 fixes the toner image on the recording material M by conveying the recording material carrying the toner image along the conveyance path TR while gripping the recording material.

  The power supply unit 22 supplies power to each member of the image forming apparatus 1 under the control of the control unit 40.

  The operation input unit 23 receives print settings for the recording material M and an operation input related to the operation of the image forming apparatus 1.

  Control unit 40 controls the overall operation of image forming apparatus 1. The control unit 40 includes a central processing unit (CPU) that executes a control program, a read only memory (ROM) that stores a control program, and a random access memory (RAM) that configures a work area of the CPU. There is.

  Each of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 detects the physical properties of the recording material M in mutually different systems under the control of the control unit 40, and sends information on the detected physical properties to the control unit 40. Output. The physical properties of the recording material detected using the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 are the basis weight of the recording material here, but other physical properties such as the thickness of the recording material may be used. Good. The detection positions of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 are upstream of the registration roller 14 along the transport path TR.

  The open / close sensor 56 detects the open state and the closed state of the paper feed tray 11, and outputs the detection result to the control unit 40.

  The image forming apparatus 1 feeds the recording material M stored in the paper feed tray 11 to the conveyance path TR one by one by the paper feed roller 12 and prints along the conveyance path TR by the conveyance roller 13 and the registration roller 14 Lead to position ST. After temporarily stopping the recording material M using the registration roller 14, the image forming apparatus 1 conveys the recording material M to the printing position ST in accordance with the timing of printing by the toner image forming unit 20.

  On the other hand, in the image forming apparatus 1, the toner image forming unit 20 generates a toner image on the intermediate transfer belt 20a of the toner image forming unit 20 by the known electrophotographic method and tandem method, and rotates the intermediate transfer belt 20a. The image is conveyed toward the printing position ST. The recording material M is fed from the resist roller 14 to the printing position ST, and the toner image is conveyed from the toner image forming unit 20. The image forming apparatus 1 transfers the toner image from the intermediate transfer belt 20 a to the recording material M at the printing position ST.

  The image forming apparatus 1 heats and presses the recording material M on which the toner image is formed by the fixing device 21. Thus, the toner image is fixed to the recording material M. Thereafter, the image forming apparatus 1 discharges the recording material M onto the sheet discharge tray 16 by the sheet discharge roller 15.

  When transporting a plurality of recording materials M stored in the paper feed tray 11 one by one, the image forming apparatus 1 determines the type of each of the plurality of recording materials M by the following method. The image forming apparatus 1 determines the type of the first recording material conveyed by the recording material conveyance unit 10 based on the output of at least one of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53. Determine. The image forming apparatus 1 is a sensor that is preferentially used when determining the types of the second and subsequent recording materials transported by the recording material transport unit 10 based on the determination result of the type of the first recording material. Are selected from the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53.

  FIGS. 2 to 6 are diagrams showing configurations of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 according to the embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the xz plane at a first position in the y-axis direction. FIG. 3 is a cross-sectional view taken along the xz plane at a second position in the y-axis direction. FIG. 4 is a view of the vicinity of the substrate 512 in the direction from the positive direction to the negative direction of the x axis. FIG. 5 is a view of the vicinity of the substrate 512 in the direction from positive to negative of the z-axis. FIG. 6 is a perspective view around the resist roller 14.

  With reference to FIGS. 2 to 6, the image forming apparatus 1 further includes two rollers 61 and a guide 62. The two rollers 61 and the guide 62 face each other across the transport path TR. The two rollers 61 are disposed on the right side of the transport path TR in FIG. The two rollers 61 are arranged in the y-axis direction. The guide 62 is disposed on the left side of the transport route TR in FIG. The recording material M fed by the paper feeding roller 12 is conveyed by the gap between the two rollers 61 and the guide 62 while the displacement of the recording material M in the thickness direction during conveyance is suppressed by the two rollers 61 and the guides 62. It is transported along the route TR.

  The optical sensor 51 is a transmitted light amount that transmits the recording material M, and a voltage value according to the transmitted light amount at a position along the conveyance direction of the recording material M (an example of information related to the transmittance of light transmitted through the recording material M) Output). The optical sensor 51 also outputs a voltage value corresponding to the amount of reflected light that passes through the recording material M. The optical sensor 51 includes substrates 511 and 512, light emitting elements 513 and 514, light receiving elements 515, and light guide plates 516 and 517.

  The substrate 511 is disposed on the right side of the transport path TR in FIG. 2 and between the two rollers 61. A light emitting element 513 is fixed to the surface of the substrate 511 facing the transport path TR. The substrate 512 is disposed on the left side of the transport path TR in FIG. A light emitting element 514 and a light receiving element 515 are fixed to the surface of the substrate 512 facing the transport path TR.

  The light guide plate 516 is provided on the right side of the transport path TR in FIG. The light guide plate 516 extends in the y-axis direction, and guides the light from the light emitting element 513 in the y-axis direction. The light guide plate 517 is provided on the left side of the transport path TR in FIG. The light guide plate 517 extends in the y-axis direction, and guides the light transmitted through the recording material M in the y-axis direction.

  The ultrasonic sensor 52 outputs a voltage value (an example of information related to the transmittance of ultrasonic waves transmitted through the recording material) according to the amount of ultrasonic waves transmitted through the recording material M. The detection position of the ultrasonic sensor 52 is on the downstream side of the conveyance path TR from the detection position of the optical sensor 51 and on the upstream side of the conveyance path TR relative to the registration roller 14. The ultrasonic sensor 52 includes a transmission substrate 521, a reception substrate 522, a transmission sensor 523 and a reception sensor 524. The transmission substrate 521 is disposed on the left side of the transport path TR in FIG. The substrate 512 and the transmission substrate 521 are arranged in the y-axis direction. The receiving substrate 522 is disposed on the right side of the transport path TR in FIG. 2 and obliquely above the transmitting substrate 521. A transmission sensor 523 is fixed to the surface of the transmission substrate 521 facing the transport path TR. A receiving sensor 524 is fixed to the surface of the receiving substrate 522 facing the transport path TR.

  The paper thickness sensor 53 is in contact with the metal roller 141. The metal roller 141 is movable in a direction AR1 perpendicular to the rotation axis of the metal roller 141. When the recording material M passes through the resist roller 14, the metal roller 141 moves in accordance with the thickness of the recording material M. The paper thickness sensor 53 includes an actuator 55 (an example of a displacement member) in contact with the metal roller 141, and outputs information on the displacement amount of the actuator 55 when the recording material M passes through the registration roller 14.

  [Method of detecting basis weight of recording material using each sensor]

  Next, a method of detecting the basis weight of the recording material using each of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 will be described.

  FIG. 7 is a view showing a method of detecting the basis weight of the recording material M using the optical sensor 51 according to an embodiment of the present invention.

  Referring to FIG. 7, control unit 40 includes a transmission source control unit 411, an averaging unit 412, a physical property detection unit 413, a determination unit 414 (a first determination unit, a selection unit, an identity determination unit, a An example of the determination unit 2) and the printing condition setting unit 415 are included. The light emitting element 514 is a light L3 that is light of each color of R (red), G (green), and B (blue) under the control of the transmission source control unit 411, and is a light L3 that becomes reflected light. Irradiate sequentially to M. The light receiving element 515 receives the reflected light L4 reflected by the recording material M, and outputs a voltage value corresponding to the received amount of reflected light to the control unit 40. The physical property detection unit 413 detects the color of the recording material M based on the voltage value corresponding to the amount of reflected light output from the light receiving element 515. In order to increase the amount of reflected light, a white back plate may be provided on the back side of the recording material M at the position where the light L3 is irradiated.

  The light emitting element 513 is light L1 having a characteristic based on the color of the recording material M detected by the physical property detection unit 413 under the control of the transmission source control unit 411, and becomes transmitted light to the recording material M The light L1 is irradiated. The light emitting element 513 emits light L1 at a timing different from the light emission timing of the light emitting element 514. The light receiving element 515 receives the transmitted light L2 (scattered light mainly scattered by the recording material M) transmitted through the recording material M, and is a transmitted light amount which is an amount of the transmitted light L2, and in the conveyance direction of the recording material M A voltage value corresponding to the amount of transmitted light at a position along the line is output to the control unit 40.

  The averaging unit 412 calculates an average value obtained by averaging the voltage values output from the light receiving element 515. The physical property detection unit 413 detects the transmittance and the basis weight of the recording material M based on the average value calculated by the averaging unit 412.

  The determination unit 414 determines the type of the recording material M by a method described later. In the present embodiment, the discrimination unit 414 discriminates the type of the recording material M from among plain paper, label paper, and backing paper. The determination unit 414 may further determine the type of the recording material M from options including the envelope and the OHP sheet.

  The printing condition setting unit 415 sets printing conditions according to the determined type of the recording material M, as described later.

  Plain paper is a sheet generally used in an image forming apparatus, and neither side of the sheet is printed. Label paper is a recording material that includes a material with an adhesive attached to the back and a mount on which the material is attached, and the material can be attached to an object by peeling the material from the mount. The backing paper is printed only on one side of plain paper. The envelope is a stack of paper in the form of a bag. The OHP sheet is a transparent film on which an image that is a basis of an image projected using an OHP (overhead projector) is drawn.

  It is expected that the basis weight can be measured for plain paper, backing paper, and label paper. It is expected that envelopes and OHP sheets can be distinguished from other recording materials.

  In order to suppress a decrease in the detection accuracy of the basis weight of the recording material M, the sheet passing width at the detection position of the optical sensor 51 (the displacement of the recording material M in the thickness direction during conveyance) It is preferable to set so as to be in a range of 1 mm to a range of ± 2 mm. The ratio (d1: d2) of the distance d2 from the light emitting element 514 to the recording material M to the distance d1 from the light emitting element 513 to the recording material M is preferably set to 6: 4. The averaging unit 412 preferably averages voltage values obtained at each of ten or more detection positions provided at a pitch of 5 mm in the recording material M. The optical sensor 51 is required to have the stability of the attitude of the recording material M at the detection position, and is required to secure the accuracy with respect to the light quantity in a wide range. The optical sensor 51 is preferably disposed near the nip of the intermediate roller.

  FIG. 8 is a view schematically showing various printing patterns of the backing sheet. 8 (a) to 8 (c), voltage values output by the optical sensor 51 when the respective back sheets are detected are also shown.

  Referring to FIG. 8, when the light guide plate 516 is provided, the light L1 can be irradiated to the wide range of the recording material M along the width direction (lateral direction in FIG. 8). When the light guide plate 517 is provided, the transmitted light L 2 from a wide range of the recording material M along the width direction is collected and received by the light receiving element 515. As a result, the voltage value output from the optical sensor 51 corresponds to the amount of light transmitted through the entire region in the direction (width direction) perpendicular to the conveyance direction of the recording material M. As a result, as shown in FIGS. 8A and 8B, in addition to the backing paper having the print pattern (the portion marked with “*” or hatching) on the center line P1 in the width direction of the recording material M, A back sheet having a print pattern on a portion other than the center line P1 as shown in 8 (c) can also be detected using the optical sensor 51.

  When the recording material M is a backing sheet, the voltage value of the optical sensor 51 is greatly reduced at the printing portion. As a result, the fluctuation amount ΔV of the voltage value output from the optical sensor 51 in the recording material M becomes larger than the predetermined amount VA. If the variation amount ΔV is larger than the predetermined amount VA, the determination unit 414 may determine that the recording material M is a backing sheet without calculating the average value in the averaging unit 412.

  Further, when the back sheet is stored in the sheet feeding tray 11 before the recording material M is stored in the sheet feeding tray 11, the recording material M is also likely to be the back sheet. When the back sheet is stored in the sheet feeding tray 11 before the recording material M is stored in the sheet feeding tray 11, the determining unit 414 determines that the fluctuation amount ΔV of the voltage value of the optical sensor 51 is a predetermined amount VB When the quantitative amount VB is larger than the predetermined amount VA, the recording material M may be determined as the backing sheet without calculating the average value in the averaging unit 412.

  FIG. 9 is a view showing a method of detecting the basis weight of the recording material M using the ultrasonic sensor 52 according to an embodiment of the present invention.

  Referring to FIG. 9, the transmission sensor 523 irradiates the recording material M with the ultrasonic wave L11 under the control of the transmission source control unit 411. The ultrasonic wave L11 may be an electromagnetic wave having a wavelength different from that of the light L1.

  The ultrasonic wave L11 is divided into an ultrasonic wave L12 transmitting the recording material M and an ultrasonic wave L13 reflected by the recording material M. The reception sensor 524 receives the ultrasonic wave L12 passing through the recording material M, and outputs a voltage value corresponding to the received ultrasonic wave amount to the control unit 40.

  The physical property detection unit 413 detects the basis weight of the recording material M based on the voltage value received from the reception sensor 524. The physical property detection unit 413 detects the recording material based on the ratio (attenuation factor) of the wave height value of the ultrasonic wave amount indicated by the voltage value output from the reception sensor 524 to the wave height value of the ultrasonic wave amount transmitted from the transmission sensor 523. Detect the basis weight of M.

  The envelope is made of overlapping paper, and has the property of being less likely to transmit ultrasonic waves than plain paper. For this reason, when the amount of ultrasonic waves (the amount of ultrasonic waves transmitted through the recording material M) indicated by the voltage value output from the reception sensor 524 is lower than a predetermined supervolume wave amount threshold TH, the determination unit 414 The recording material M may be determined as an envelope regardless of the detection result of the basis weight using the sensor of (1). In particular, it is preferable that an angle θ formed by the transmission direction of the ultrasonic wave L11 by the transmission sensor 523 with respect to the transport path TR be 38 degrees or more and 45 degrees or less. In this angle range, the decrease in the amount of ultrasonic waves in the case where the recording material is an envelope becomes remarkable, and by employing this angle range, it is possible to improve the detection accuracy of the envelope.

  In order to suppress the decrease in the detection accuracy of the basis weight of the recording material M, the sheet passing width at the detection position of the ultrasonic sensor 52 is preferably set within 2.4 mm. This is because the recording material M is required to have the stability of the posture at the detection position of the ultrasonic sensor 52.

  FIG. 10 is a view showing a method of detecting the basis weight of the recording material M using the paper thickness sensor 53 according to the embodiment of the present invention.

  Referring to FIG. 10, paper thickness sensor 53 includes a sensor unit 54 and an actuator 55. The sensor unit 54 detects the amount of movement of the actuator 55, and outputs information indicating the detected amount of movement to the control unit 40. The sensor unit 54 includes two support units 541, a pedestal unit 542, an irradiation unit 543, and a light receiving unit 544. The two supports 541 pivotally support the actuator 55 therebetween. The pedestal portion 542 fixes two support portions 541. The irradiation unit 543 is provided inside the one support unit 541 and irradiates the encoder unit 552 of the actuator 55 with light. The light receiving unit 544 is provided inside the other support unit 541, and receives the light from the irradiation unit 543 transmitted through the encoder unit 552. The light receiving unit 544 outputs information corresponding to the received light amount to the control unit 40.

  The actuator 55 is movable around the rotation axis 554 in both the direction indicated by the arrow SA and the direction indicated by the arrow SB. The actuator 55 includes a contact portion 551, an encoder portion 552, an arm portion 553, and a rotation shaft 554.

  The contact portion 551 is in contact with the metal roller 141. The contact portion 551 has an arc shape.

  The encoder unit 552 includes a plurality of high transmittance portions 552a and a plurality of low transmittance portions 552b. The transmittance of the high transmittance portion 552a is higher than the transmittance of the low transmittance portion 552b. Each of the plurality of high transmittance portions 552 a and each of the plurality of low transmittance portions 552 b are alternately arranged along the swing direction of the actuator 55. Thereby, the transmittance of the portion of the encoder unit 552 to which the light is irradiated from the irradiation unit 543 periodically changes due to the movement of the actuator 55. The arm portion 553 connects the contact portion 551 and the encoder portion 552. Thereby, the contact portion 551 and the encoder portion 552 integrally swing. The rotation shaft 554 is fixed near the boundary between the encoder 552 and the arm 553. The rotation shaft 554 extends in the thickness direction.

  The physical property detection unit 413 detects the basis weight of the recording material M based on the information output from the light receiving unit 544.

  FIG. 11 is a diagram schematically showing information output by the sensor unit 54 in the embodiment of the present invention. FIG. 11A shows an output of the sensor unit 54 when the actuator 55 moves in the positive direction (arrow SA direction). FIG. 11B shows the output of the sensor unit 54 when the actuator 55 moves in the negative direction (arrow SB direction).

  Referring to FIG. 11, light receiving unit 544 outputs two phases of A phase and B phase. Each of the A-phase and the B-phase is a pulse, and the phase of the movement direction (the thickness direction of the recording material M) of the actuator 55 is shifted by 90 degrees. Thereby, the thickness can be measured with resolution (accuracy) corresponding to the distance PE between pulse edges. This resolution is, for example, 5 μm.

  The transmittance of the portion of the encoder unit 552 to which light is emitted from the irradiation unit 543 periodically changes as the amount of movement of the actuator 55 in the positive direction or the negative direction increases. The amount of light received by the light receiving unit 544 of the sensor unit 54 also periodically changes as the movement amount of the actuator 55 increases. As a result, as described above, each of the A-phase and the B-phase has a high (H) state with a period corresponding to twice the distance PE as the amount of movement of the actuator 55 in the positive or negative direction increases. It becomes a pulse which repeats the state of low (L).

  In order to suppress the wear of the contact portion 551, the displacement of the metal roller 141 accompanied by the passage of the recording material M is an actuator 55 while the contact portion 551 indirectly contacts the recording material M in the paper thickness sensor 53. It is required to be arranged so as to be accurately transmitted.

  The optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 may detect physical properties of the recording material M while being conveyed (moving) by the recording material conveyance unit 10, or temporarily stop using the resist roller 14. The physical properties of the recording material M in the set state may be detected.

  [Detection accuracy of physical properties using each sensor]

  FIG. 12 is a graph showing the relationship between the transmittance of light transmitted through the recording material detected using the optical sensor 51 according to an embodiment of the present invention and the actual basis weight of the recording material.

  Referring to FIG. 12, physical property detection unit 413 stores curve LN1. The curve LN1 is a change in the basis weight of the basis weight according to the transmittance of light (transmitted light L2) transmitted through the recording material detected using the optical sensor 51 (hereinafter sometimes referred to as the transmittance of the recording material) Is a reference curve on two-axis coordinates indicating. The curve LN1 is calculated from the relationship obtained when the recording material is plain paper. The physical property detection unit 413 detects the transmittance of the recording material based on the amount of light transmitted through the recording material. The physical property detection unit 413 detects the basis weight of the recording material using the curve LN1 based on the detected transmittance of the recording material.

  When the recording material is plain paper, a point indicating the relationship between the detected transmittance of the recording material and the actual basis weight of the recording material exists substantially on the curve LN1. On the other hand, when the recording material is a backing sheet, an envelope, or a label sheet, the point indicating the relationship between the detected transmittance of the recording material and the actual basis weight of the recording material deviates from the curve LN1.

  Specifically, when the recording material is a backing sheet or an envelope, the basis weight obtained from the curve LN1 based on the detected transmittance of the recording material is larger than the actual basis weight. This is because there is a printed portion on the backing paper, and it becomes difficult to transmit light as compared to plain paper. The envelope is made of overlapping paper, and light is less likely to be transmitted as compared to plain paper. When the recording material is a label sheet, the basis weight obtained from the curve LN1 based on the detected transmittance of the recording material is smaller than the actual basis weight. Label paper has a larger specific gravity than plain paper.

  In addition, when looking at the detection accuracy of the basis weight detected using the curve LN1 based on the transmittance, in the range where the transmittance of light passing through the recording material is larger than 8.0% (range RG1) It can be seen that the deviation from the curve LN1 of the point indicating the relationship between the transmittance and the actual basis weight of the recording material is small, and the detection accuracy of the basis weight detected using the curve LN1 is high. When the transmittance of light passing through the recording material is in the range of 8.0% or less, the deviation from the curve LN1 indicating the relationship between the transmittance and the actual basis weight of the recording material is large, and detection using the curve LN1 It can be seen that the detection accuracy of the basis weight to be measured is low.

  Although not shown in the graph of FIG. 12, the transmissivity of the OHP sheet is extremely high (compared to a predetermined transmissivity threshold value) as compared with plain paper, label paper, backing paper, envelopes, etc. Too expensive). Therefore, the optical sensor 51 can be used to detect that the recording material is an OHP sheet.

  FIG. 13 is a view showing the relationship between the voltage value output from the ultrasonic sensor 52 and the actual basis weight of the recording material in the embodiment of the present invention.

  Referring to FIG. 13, physical property detection unit 413 stores curve LN2. A curve LN2 is a reference curve showing the relationship between the voltage value output from the ultrasonic sensor 52 and the actual basis weight of the recording material. The curve LN2 is a reference curve calculated from the relationship obtained when the recording material is plain paper. The physical property detection unit 413 detects the basis weight of the recording material using the curve LN2 based on the voltage value output from the ultrasonic sensor 52.

  When the recording material is plain paper, label paper, or backing paper, a point indicating the relationship between the voltage value and the actual basis weight of the recording material lies approximately on the curve LN2. In particular, when the recording material is a backing sheet, the print portion has almost no influence on the ultrasonic waves. On the other hand, when the recording material is an envelope, the point indicating the relationship between the voltage value and the actual basis weight of the recording material deviates from the curve LN2. When the recording material is an envelope, the basis weight of the recording material detected using the curve LN2 based on the voltage value is larger than the actual basis weight. The envelope is made of overlapping paper, and is less likely to transmit ultrasonic waves than plain paper.

  When looking at the detection accuracy of basis weight obtained using curve LN2 based on the voltage value, the voltage value and the actual basis weight of the recording material are within the range of 2.8 V or more (range RG2). It can be seen that the deviation from the curve LN2 of the point indicating the relationship with the amount is small, and the detection accuracy of the basis weight detected using the curve LN2 is high. When the voltage value is less than 2.8 V, the deviation from the curve LN2 of the point indicating the relationship between the voltage value and the actual basis weight of the recording material is large, and the detection accuracy of the basis weight detected using the curve LN2 is It is understood that it is low. Here, the range in which the voltage value is 2.8 V or more corresponds to the range (range RG2) in which the light transmittance in the graph of FIG. 12 is 2.8% or more.

  FIG. 14 is a graph showing the relationship between the basis weight of the recording material detected using the paper thickness sensor 53 according to the embodiment of the present invention and the actual basis weight of the recording material.

Referring to FIG. 14, in the range where the detected basis weight of the recording material is larger than 200 g / m ² (range RG3), the deviation of the detected basis weight of the recording material from the actual basis weight of the recording material is small. It can be seen that the detection accuracy of the basis weight detected using the paper thickness sensor 53 is high. When the basis weight of the detected recording material is 200 g / m ² or less, the detected basis weight of the recording material deviates from the actual basis weight of the recording material, and the basis weight detected using the paper thickness sensor 53 It can be seen that the detection accuracy of is low. Here, the range in which the basis weight of the detected recording material is larger than 200 g / m ² corresponds to the range (range RG3) in which the light transmittance in the graph of FIG. 12 is less than 2.8%.

  FIG. 15 is a view showing detection accuracy of each of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 with respect to various recording materials.

Referring to FIG. 15, the optical sensor 51 detects the basis weight of thin plain paper (basis weight: 150 g / m ² or less), and detects the basis weight of thick plain paper (basis weight: 150 g / m ² or more) And high accuracy in the determination of OHP sheets. The ultrasonic sensor 52 has high accuracy in detection of a basis weight of thin backing paper (basis weight: 150 g / m ² or less), discrimination of label paper, and discrimination of an envelope. The paper thickness sensor 53 has high accuracy in detecting the basis weight of thick plain paper (basis weight: 150 g / m ² or more) and the basis weight of thick backing paper (basis weight: 150 g / m ² or more) doing.

  [How to determine the type of first recording material]

  As described above, the types of sensors capable of detecting the basis weight with high accuracy differ depending on the transmittance of the recording material. For this reason, when printing is performed by transporting a plurality of recording materials one by one by the recording material transport unit 10, the determination unit 414 performs the following for the type of the first recording material based on the outputs of the plurality of sensors. Determine by the method of

  The “first sheet of recording material” may be the first sheet of recording material conveyed by the recording material conveyance unit 10 after the sheet feeding tray 11 is switched from the open state to the closed state. The first recording material of the print job may be used.

  FIG. 16 is a diagram showing a combination of the transmittance of the recording material and the sensor used for basis weight detection in the embodiment of the present invention.

  Referring to FIGS. 12 and 16, the determination unit 414 has a transmittance of the recording material detected using the optical sensor 51 (a transmittance of the recording material indicated by the information output by the optical sensor 51) of 8.0%. In the range RG1 larger than (an example of the first threshold), the basis weight of the recording material is determined based on the output of the optical sensor 51 among the optical sensor 51, the ultrasonic sensor 52, and the sheet thickness sensor 53. Identify (detect)

  When the transmittance of the recording material detected using the optical sensor 51 is within the range RG2 of not less than 2.8% (an example of the second threshold) and not more than 8.0%, the determination unit 414 determines the optical sensor 51. The basis weight of the recording material is specified (detected) based on the output of the ultrasonic sensor 52 among the ultrasonic sensor 52 and the paper thickness sensor 53.

  Among the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53, when the transmittance of the recording material detected using the optical sensor 51 is within the range RG3 of less than 2.8%, the determination unit 414 is used. The basis weight of the recording material is specified (detected) based on the output of the paper thickness sensor 53.

  FIG. 17 is a graph showing a method of determining the type of recording material according to the embodiment of the present invention. The vertical axis in the graph is the detected basis weight, and the horizontal axis is the transmittance of the recording material.

  Referring to FIG. 17, next, the discrimination unit 414 discriminates the type of the recording material based on the state of deviation of the specified physical property from the reference value. The determination unit 414 plots points (for example, points PT1 to PT3) indicating the transmittance of the recording material and the detected basis weight on two-axis coordinates. The determination unit 414 determines the type of recording material from among plain paper, label paper, and backing paper based on the state of deviation of the plotted points from the curve LN1.

  Specifically, when the plotted points exist in the area G1 not diverging from the curve LN1 (when the plotted points are, for example, the point PT1), the discrimination unit 414 determines that the type of recording material is plain paper. Determine that there is. When the recording material is plain paper, as shown in FIG. 12, the actual basis weight is approximately the same as the basis weight detected using the optical sensor 51.

  When the plotted points exist in the area G2 separated downward from the curve LN1 (when the plotted points are, for example, the points PT2), the discrimination unit 414 determines that the type of the recording material is the back sheet. To determine. When the recording material is a backing sheet, as shown in FIG. 12, the actual basis weight is smaller than the basis weight detected using the optical sensor 51.

  Furthermore, when the plotted point exists in the area G3 which deviates upward from the curve LN1 (when the plotted point is, for example, the point PT3), the discrimination unit 414 determines that the type of recording material is label paper. To determine. When the recording material is a label sheet, as shown in FIG. 12, the actual basis weight is larger than the basis weight detected using the optical sensor 51.

  [How to determine the type of recording material for the second and subsequent sheets]

  As for the type of recording material for the second and subsequent sheets, the determination unit 414 is a sensor out of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 based on the determination result of the type of the first recording material. Select and determine using the selected sensor preferentially.

  Note that “the second and subsequent recording materials” is a recording material conveyed by the recording material conveyance unit 10 until the sheet feeding tray 11 is switched to the open state again after the conveyance of the first recording material. The recording material may be the second and subsequent sheets of the print job.

  The determination unit 414 is a sensor used to specify the basis weight of the first recording material as a sensor that is preferentially used when determining the type of the second and subsequent recording materials (the transmittance of the recording material) Is within the range RG1: optical sensor 51, recording material transmittance is within the range RG2: ultrasonic sensor 52, recording material transmittance is within the range RG3: paper thickness sensor 53) Do. The determination unit 414 determines the identity between the type of each of the second and subsequent recording materials determined based on the output of the selected sensor and the type of the first recording material. The identity between the type of each of the second and subsequent recording materials and the type of the first recording material is determined by comparing the basis weight of each of the second and subsequent recording materials with the basis weight of the first recording material. It may be determined based on the identity.

  When it is determined that the types of the second and subsequent recording materials are different from the type of the first recording material, the determination unit 414 determines the type of the recording material and the type of the first recording material. Similar to the above, the determination is made based on the outputs of multiple sensors. In this case, preferably, the type of the recording material is determined based on at least the output of the optical sensor 51. Further, in this case, the recording material conveyance unit 10 may decrease the conveyance speed of the recording material until the determination unit 414 determines the type of the recording material, and the toner image forming unit 20 is configured of the recording material. Printing on the recording material may not be started until the discrimination unit 414 discriminates the type.

  [How to determine printing conditions]

  FIG. 18 is a view schematically showing a setting table in the embodiment of the present invention.

  Referring to FIG. 18, printing condition setting unit 415 sets printing conditions according to the determined type of recording material using the setting table.

  The setting table describes printing conditions set when the type of recording material determined is plain paper, label paper, backing paper, envelope, and OHP sheet. The printing conditions include system speed (printing speed), recording material interval, transfer current, fixing temperature, fixing pressure (pressure contact between fixing member and pressing member), FS (finisher) prohibition (prohibition regarding post processing) Each item of double-sided prohibition (double-sided printing prohibition) and printing direction are included.

  If there is a recording material on the back side, double-sided printing is prohibited because there are already printed characters on the back side. When the recording material is label paper, the system speed is set to a different value (slower value) than the system speed when the recording material is plain paper by switching between the medium speed and the low speed. And the fixing heat is efficiently transmitted to the recording material.

  The printing conditions in FIG. 18 are an example, and the printing conditions set according to the type of recording material are arbitrary. The printing condition setting unit 415 determines that the system speed when the recording material is determined to be a label sheet is different from the printing speed when the recording material is determined to be a plain sheet (the printing speed is lower than the printing speed when determined to be a plain sheet) It is preferable to set to the value). Further, it is preferable that the printing condition setting unit 415 prohibits double-sided printing when it is determined that the recording material is a back sheet, and does not receive the setting of double-sided printing through the operation input unit 23.

  The printing condition setting unit 415 may set printing conditions according to the basis weight of the recording material in addition to the type of the recording material.

  [flowchart]

  19 and 20 are flowcharts showing the operation of the image forming apparatus 1 according to the embodiment of the present invention.

  Referring to FIG. 19, control unit 40 determines whether a print request has been received (S1). The control unit 40 repeats the process of step S1 until it determines that the print request has been received.

  In step S1, when it is determined that the print request has been received (YES in S1), the control unit 40 starts feeding the recording material from the paper feed tray 11 (S3), and the registration roller 14 feeds the recording material. Stop (S5). Subsequently, the control unit 40 determines whether the recording material being conveyed is the first recording material after being set (replenished) on the recording material on the paper feed tray 11 (S7).

  In step S7, when it is determined that the recording material being conveyed is the first recording material (YES in S7), the control unit 40 performs type determination processing using a plurality of sensors to determine the type of recording material. To do (S17). Next, the control unit 40 changes the printing conditions in accordance with the determined type of recording material (S19), and resumes conveyance of the recording material in synchronization with the image (S21). Next, the control unit 40 prints on the recording material (S23), discharges the printed recording material (S25), and ends the process.

  In step S7, when it is determined that the recording material being conveyed is the recording material for the second and subsequent sheets (NO in S7), the control unit 40 specifies (detects) the basis weight of the first recording material. The basis weight of the recording material is detected using the sensor used in (S9). Subsequently, the control unit 40 determines whether the detected basis weight is the same as the basis weight of the first recording material (S11).

  In step S11, when it is determined that the detected basis weight is the same as the basis weight of the first recording material (YES in S11), the control unit 40 records the first recording material type being conveyed. It discriminate | determines that it is the same as the kind of material (S13), and progresses to the process of step S21.

  When it is determined in step S11 that the detected basis weight is different from the basis weight of the first recording material (NO in S11), the control unit 40 determines that the type of recording material being conveyed is the first recording material. It is determined that the type is different from the type, and the print timing is delayed (S15). Next, the control unit 40 proceeds to the process of step S17, performs type determination processing using a plurality of sensors, and determines the type of recording material (S17). After that, the control unit 40 performs the process after step S19.

  FIG. 20 is a subroutine of step S17 of FIG.

  Referring to FIG. 20, in the type determination process using a plurality of sensors in step S17, control unit 40 detects the transmittance of the recording material using optical sensor 51 (S101), and the detected transmittance is 8. It is determined whether it is 0% or more (S103).

  In step S103, when it is determined that the detected transmittance is 8.0% or more (YES in S103), the control unit 40 detects the basis weight of the recording material using the optical sensor 51 (S105), and the step The process proceeds to the process of S113.

  If it is determined in step S103 that the detected transmittance is less than 8.0% (NO in S103), the control unit 40 determines whether the detected transmittance is 2.8% or more (S103). S107).

  If it is determined in step S107 that the detected transmittance is 2.8% or more (YES in S107), the control unit 40 detects the basis weight of the recording material using the ultrasonic sensor 52 (S109), The process proceeds to step S113.

  In step S107, when it is determined that the detected transmittance is less than 2.8% (NO in S107), the control unit 40 detects the basis weight of the recording material using the paper thickness sensor 53 (S111), The process proceeds to step S113.

  In step S113, the control unit 40 plots points indicating the transmittance of the recording material and the detected basis weight (S113). Subsequently, the control unit 40 determines whether the position of the point deviates lower than the curve LN1 (S115).

  In step S115, when it is determined that the position of the point deviates lower than the curve LN1 (YES in S115), the control unit 40 determines that the recording material is the back sheet (S117), and returns. .

  If it is determined in step S115 that the position of the point does not deviate downward from the curve LN1 (NO in S115), the control unit 40 determines whether the position of the point deviates upward from the curve LN1. It is determined (S119).

  In step S119, when it is determined that the position of the point deviates upward from the curve LN1 (YES in S119), the control unit 40 determines that the recording material is a label sheet (S121), and returns. .

  In step S119, when it is determined that the position of the point does not deviate upward from the curve LN1 (NO in S119), the control unit 40 determines that the recording material is plain paper (S123), and returns. .

  [Effect of the embodiment]

  In the present embodiment, the type of the second and subsequent recording materials to be conveyed is determined by preferentially using the sensor selected based on the determination result of the type of the first recording material to be conveyed. Ru. As a result, it is possible to suppress the decrease in the determination accuracy of the type of recording material, as compared with the case where the type of recording material of the second and subsequent sheets is not determined. In addition, since it is easy to determine the type of recording material for the second and subsequent sheets, the type of recording material is determined in comparison with the case where the types of all recording materials conveyed are determined using a plurality of sensors 51. The time required for the sensor can be shortened, and the decrease in sensor life can be suppressed.

  [Others]

  The recording material discriminating apparatus of the present invention may discriminate the type of the recording material from the options of at least a part of the plain paper, the label paper, the backing paper, the envelope, and the sheet for OHP. The basis weight of the recording material may be detected without detecting the type.

  The processing in the above embodiment may be performed by software or may be performed using a hardware circuit. In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is provided to the user by being recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card. You may decide to do it. The program is executed by a computer such as a CPU. Also, the program may be downloaded to the device via a communication line such as the Internet.

  The embodiments described above are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

1 Image forming apparatus (an example of a recording material determination apparatus)
1a Image forming apparatus main body 10 Recording material conveyance unit (an example of conveyance means)
11 Paper feed tray (an example of a storage unit)
12 paper feed roller 13 conveyance roller 14 registration roller 15 paper discharge roller 16 paper discharge tray 20 toner image formation section (an example of printing means)
20a Intermediate Transfer Belt 21 Fixing Device 22 Power Supply Unit 23 Operation Input Unit 40 Control Unit 51 Optical Sensor 52 Ultrasonic Sensor 53 Paper Thickness Sensor 54 Sensor Unit 55 Actuator 56 Open / Close Sensor 61 Roller 62 Guide 141 Metal Roller 142 Rubber Roller 411 Source Control Unit 412 averaging unit 413 physical property detection unit 414 determination unit (first determination unit, selection unit, identity determination unit, and example of second determination unit)
415 print condition setting unit 511, 512 substrate 513, 514 light emitting element 515 light receiving element 516, 517 light guide plate 521 transmission substrate 522 reception substrate 523 transmission sensor 524 reception sensor 541 support unit 542 pedestal unit 543 irradiation unit 544 light receiving unit 551 contact unit 552 Encoder 552a High transmittance part 552b Low transmittance part 553 Arm 554 Rotation axis AR1 Movement direction of metal roller G1, G2, G3 Area of two-axis coordinate L1, L3 Light L2 Transmitted light L4 Reflected light L11, L12, L13 Super Sound wave LN1 Reference curve on biaxial coordinates showing change in basis weight according to the transmittance of light (light L1) transmitted by the recording material detected by the first physical property detection means LN2 Ultrasonic sensor outputs Curve M showing the relationship between the voltage value and the actual basis weight of the recording material The distance between the first center line PE pulse edge PT1, PT2, PT3 points on 2-axis coordinate RG1, RG2, RG3 range of the light transmittance SA, moving direction ST printing position TR conveyance path SB actuator

Claims (12)

Transport means for transporting the recording material;
Each of a plurality of sensors that output information on the physical properties of the recording material detected by different methods,
When the plurality of recording materials are conveyed one by one by the conveyance unit, the type of the first recording material conveyed by the conveyance unit is determined based on the outputs of the plurality of sensors. Determining means;
Based on the determination result of the type of the first recording material by the first determination means, the method is preferentially used when determining the types of the second and subsequent recording materials conveyed by the conveyance means. A recording material discrimination device comprising: selection means for selecting a sensor from among the plurality of sensors. The printing apparatus further comprises printing means for printing on the recording material conveyed by the conveying means,
The conveying means includes a resist roller for conveying the recording material to the printing position by the printing means in accordance with the timing of printing by the printing means.
The recording material discrimination device according to claim 1, wherein a detection position of each of the plurality of sensors is upstream of the resist roller along the conveyance path of the recording material. The identity of the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection unit and the type of the first recording material determined by the first determination unit Identity determination means for determining
If the types of the second and subsequent recording materials determined based on the output of the sensor selected by the selection unit are different from the types of the first recording material determined by the first determination unit 2. The image forming apparatus according to claim 1, further comprising: a second determination unit configured to determine the type of the second and subsequent recording materials based on the outputs of the plurality of sensors when determined by the identity determination unit. The recording material discrimination device according to 2.   The transport unit is configured to select the types of the second and subsequent recording materials determined based on the output of the sensor selected by the selection unit, and the first recording material determined by the first determination unit. The conveyance of the second and subsequent sheets of recording material is continued until the type of the second and subsequent sheets of recording material is determined by the second identification means when the identity determination means determines that the type is different. The recording material discriminating apparatus according to claim 3, wherein the speed is reduced.   The printing unit is a type of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selection unit, and the first recording material discriminated by the first discrimination unit. When it is determined by the identity determining unit that the type is different, printing on the second and subsequent recording materials is performed until the type of the second and subsequent recording materials is determined by the second determining unit. The recording material discrimination device according to claim 3 or 4, wherein the recording material discrimination device does not start. The plurality of sensors include an optical sensor that outputs information on the transmittance of light transmitted through the recording material,
The recording material discriminating apparatus according to any one of claims 3 to 5, wherein the second discriminating means discriminates the type of the second and subsequent recording materials based on at least an output of the optical sensor. The plurality of sensors are
An optical sensor that outputs information on the transmittance of light passing through the recording material;
And an ultrasonic sensor for outputting information on the transmittance of ultrasonic waves transmitted through the recording material,
The first determination means is
When the transmittance of the first recording material indicated by the information output by the optical sensor is larger than the first threshold, the physical properties of the first recording material are calculated based on the output of the optical sensor. When the transmittance of the first recording material specified by the information output from the optical sensor is smaller than the first threshold and larger than the second threshold, the ultrasonic wave is detected. Specifying means for specifying the physical properties of the first recording material based on the output of the sensor;
The deviation determining means according to any one of claims 1 to 6, further comprising: a deviation determining means for determining the type of the first recording material based on a state of deviation of the physical property specified by the specifying means from a reference value. Recording material discrimination device. The plurality of sensors further include a paper thickness sensor that outputs information on the displacement amount of the displacement member when the recording material passes the detection position of the displacement member,
When the transmittance of the first recording material indicated by the information output from the optical sensor is smaller than the second threshold, the specifying unit determines the number of sheets based on the output of the sheet thickness sensor. The recording material determination apparatus according to claim 7, wherein physical properties of the recording material of the eye are specified.   9. The recording material discrimination method according to claim 7, wherein the selecting unit selects the sensor used by the specifying unit to specify the physical property of the first recording material as the sensor to be preferentially used. apparatus. The first determination means plots on a two-axis coordinate a point indicating the transmittance of the first recording material indicated by the information output by the optical sensor and the physical property specified by the specifying means. Further including plotting means,
The deviation determining means determines a point plotted by the plotting means based on a state of deviation from the reference curve on the two-axis coordinate that indicates a change in the reference value according to a change in the transmittance of the recording material. The recording material determination device according to any one of claims 7 to 9, wherein the type of the recording material is determined. A storage unit for storing a recording material, and in an open state in which the recording material can be replenished from the outside of the recording material discrimination device and in a closed state in which the recording material can not be replenished from the exterior of the recording material discrimination device The switch further comprises a switchable storage unit,
The first sheet of recording material is the first sheet of recording material conveyed by the conveyance means after the storage portion is switched from the open state to the closed state.
The recording material of the second and subsequent sheets is a recording material which is conveyed by the conveyance unit until the storage portion is switched to the open state again after the conveyance of the first recording material. The recording material determination device according to any one of the above. A control method of a recording material discriminating apparatus, comprising: conveying means for conveying a recording material; and each of a plurality of sensors for outputting information on physical properties of the recording material detected by different methods.
When the plurality of recording materials are conveyed one by one by the conveyance unit, the type of the first recording material conveyed by the conveyance unit is determined based on the outputs of the plurality of sensors. A determination step;
Based on the determination result of the type of the first recording material in the first determination step, prioritizing the type of the second and subsequent recording materials conveyed by the conveyance means And a selection step of selecting a sensor from among the plurality of sensors.

Images