JP7009949B2 - Recording material discrimination device and control method of recording material discrimination device - Google Patents

Description

The present invention relates to a recording material discriminating device and a control method of the recording material discriminating device. More specifically, the present invention relates to a recording material discriminating device for discriminating the type of recording material and a control method for the recording material discriminating device.

The electrophotographic image forming apparatus includes an MFP (Multifunction Peripheral) having a scanner function, a facsimile function, a copying function, a printer function, a data communication function, and a server function, a facsimile machine, a copying machine, a printer, and the like. be.

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

Therefore, a recording material discrimination device (media) that reduces 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 discriminating the type of recording material based on the physical characteristics. The sensor) is proposed in the following Patent Document 1 and the like.

In the following Patent Document 1, the type of the first recording material is discriminated, the image is formed under the image forming conditions according to the type of the discriminated recording material, and the type of the second and subsequent recording materials is formed. A technique for forming an image without discriminating between the two is disclosed.

U.S. Pat. No. 7783211

In recent years, there are a wide variety of recording materials used in image forming apparatus. Especially for backing paper and label paper, it is not possible to detect the type using a conventional media sensor. In order to improve the accuracy of discriminating the type of recording material, the image forming apparatus is a plurality of sensors suitable for detecting each type of recording material, and is a plurality of sensors that detect the physical properties of the recording material by different methods. Need to be installed. Then, the image forming apparatus operates a plurality of sensors each time the recording material is passed, or performs a process of determining a sensor to be preferentially used when determining the type of the recording material from the plurality of sensors. There is a need to. For this reason, there is a problem that the life of the sensor is shortened by operating a plurality of sensors each time the recording material is passed, and there is a problem that it takes time to determine the type of the recording material.

Here, according to the technique of Patent Document 1, it is possible to suppress a decrease in the life of the sensor by forming an image without discriminating the type of the second and subsequent recording materials, and the type of recording material. It is possible to shorten the time for discriminating. However, in the technique of Patent Document 1, since the type of the recording material for the second and subsequent sheets is not discriminated, when the type of the recording material for the second and subsequent sheets is different from the type of the recording material for the first sheet, the recording material is used. This has led to a decrease in the accuracy of type discrimination. As a result, it is not possible to print the second and subsequent recording materials under the optimum printing conditions, and there is a problem that the image quality is deteriorated.

The present invention is for solving the above-mentioned problems, and an object thereof is a recording material discriminating device and a recording material capable of suppressing a decrease in the life of a sensor while suppressing a decrease in the accuracy of discriminating the type of recording material. It is to provide the control method of the discriminator.

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

The recording material discriminating device according to one aspect of the present invention includes a transporting means for transporting the recording material, a plurality of sensors for outputting information on the physical properties of the recording material detected by different methods, and a plurality of transporting means. When transporting the recording materials one by one, the first discriminating means and the first discriminating means for discriminating the type of the first recording material transported by the transporting means based on the outputs of a plurality of sensors. Among a plurality of sensors, the sensor preferentially used when discriminating the type of the second and subsequent recording materials to be conveyed by the conveying means based on the determination result of the type of the first recording material by It is provided with a selection means for selecting from.
In the recording material discriminating device, the types of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means and the first recording material determined by the first discriminating means are preferable. The identity discriminating means for discriminating the identity with the type, the type of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selecting means, and the one discriminated by the first discriminating means. When it is determined by the identity determination means that the type of the recording material of the eye is different, the second determination means for determining the type of the second and subsequent recording materials based on the outputs of a plurality of sensors is further added. Be prepared.
In the recording material discrimination device, preferably, the transport means is the type of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selection means, and the first sheet discriminated by the first discriminating means. When it is determined by the identity determination means that the type of the recording material is different from that of the recording material, the second and subsequent recording materials are conveyed until the type of the second and subsequent recording materials is determined by the second determination means. Slow down.

The recording material discriminating device preferably further includes 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 in accordance with the printing timing by the printing means. The detection position of each of the plurality of sensors including the resist roller for transporting the material is upstream of the resist roller along the transport path of the recording material.

In the recording material discriminating device, the types of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means and the first recording material determined by the first discriminating means are preferable. The identity discriminating means for discriminating the identity with the type, the type of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selecting means, and the one discriminated by the first discriminating means. When it is determined by the identity determination means that the type of the recording material of the eye is different, the second determination means for determining the type of the second and subsequent recording materials based on the outputs of a plurality of sensors is further added. Be prepared.

In the recording material discrimination device, preferably, the transport means is the type of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selection means, and the first sheet discriminated by the first discriminating means. When it is determined by the identity determination means that the type of the recording material is different from that of the recording material, the second and subsequent recording materials are conveyed until the type of the second and subsequent recording materials is determined by the second determination means. Slow down.

In the recording material discrimination device, preferably, the printing means is the type of the second and subsequent recording materials discriminated based on the output of the sensor selected by the selection means, and the first sheet discriminated by the first discriminating means. When it is determined by the identity determination means that the type of the recording material is different from that of the 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 means. Do not start.

In the recording material discriminating device, preferably, the plurality of sensors include an optical sensor that outputs information regarding the transmittance of light transmitted through the recording material, and the second discriminating means is at least two based on the output of the optical sensor. Determine the type of recording material after the eyes.

In the recording material discrimination device, preferably, 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. When the transmittance of the first recording material indicated by the information output by the optical sensor is larger than the first threshold value, the first discriminating means includes one sheet based on the output of the optical sensor. When 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 the range smaller than the first threshold value and larger than the second threshold value. , The first recording material based on the specific means for specifying the physical properties of the first recording material based on the output of the ultrasonic sensor and the state of deviation of the physical properties specified by the specific means from the reference value. Includes a divergence determination means for determining the type of.

In the recording material discriminating device, preferably, 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 through the detection position of the displacement member, and the specific means is an optical sensor. When the transmission rate of the first recording material indicated by the information output in is smaller than the second threshold value, the physical properties of the first recording material are specified based on the output of the paper thickness sensor.

In the recording material discrimination device, the selection means preferably selects the sensor used by the specific means to specify the physical properties of the first recording material as the sensor to be used preferentially.

In the recording material discriminating device, the first discriminating means preferably has two axes of a point indicating the transmittance of the first recording material indicated by the information output by the optical sensor and the physical properties specified by the specific means. The plotting means for plotting on the coordinates is further included, and the deviation discriminating means is from the reference curve on the biaxial coordinates showing the change of the reference value according to the change in the transmittance of the recording material at the points plotted by the plotting means. The type of recording material is determined based on the state of deviation.

In the recording material discriminating device, the accommodating portion for accommodating the recording material is preferably in an open state in which the recording material can be replenished from the outside of the recording material discriminating device, and the recording material cannot be replenished from the outside of the recording material discriminating device. The first recording material is further provided with an accommodating portion that can be switched between the closed state and the accommodating portion, and the first recording material is conveyed by the conveying means after the accommodating portion is switched from the open state to the closed state. The second and subsequent recording materials are recording materials that are conveyed by the conveying means until the accommodating portion is switched to the open state again after the first recording material is conveyed.

A control method for a recording material discriminating device according to another aspect of the present invention includes a transporting means for transporting the recording material and a plurality of sensors for outputting information on the physical properties of the recording material detected by different methods. In the control method of the material discrimination device, when a plurality of recording materials are conveyed one by one by the conveying means, the type of the first recording material conveyed by the conveying means is set to the output of a plurality of sensors. Based on the first discriminating step for discriminating based on the discriminating result and the discriminating result of the type of the first recording material by the first discriminating step, the types of the second and subsequent recording materials transported by the transport means are discriminated. It is provided with a selection step of selecting a sensor to be preferentially used when performing the operation from a plurality of sensors.

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

It is sectional drawing which shows typically the structure of the image forming apparatus 1 in one Embodiment of this invention. It is a figure which shows the structure of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 in one Embodiment of this invention, and is the case where it cuts in the xz plane at the 1st position in the y-axis direction. It is a cross-sectional view. It is a figure which shows the structure of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 in one Embodiment of this invention, and is the case where it cuts in the xz plane at the 2nd position in the y-axis direction. It is a cross-sectional view. It is a figure which shows the structure of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 in one Embodiment of this invention, and is the vicinity of the substrate 512 in the direction from the positive to the negative direction of the x-axis. It is a figure when seen. It is a figure which shows the structure of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 in one Embodiment of this invention, and looked at the vicinity of the substrate 512 in the direction from positive to negative of the z-axis. It is a figure of the case. It is a figure which shows the structure of a part of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 in one Embodiment of this invention, and is the perspective view around the resist roller 14. It is a figure which shows the detection method of the basis weight of the recording material M using the optical sensor 51 in one Embodiment of this invention. It is a figure which shows typically the various printing patterns of the backing paper. It is a figure which shows the detection method of the basis weight of the recording material M using the ultrasonic sensor 52 in one Embodiment of this invention. It is a figure which shows the detection method of the basis weight of the recording material M using the paper thickness sensor 53 in one Embodiment of this invention. It is a figure which shows typically the information output by the sensor part 54 in one Embodiment of this invention. It is a graph which shows the relationship between the transmittance of the light transmitted through the recording material detected by using the optical sensor 51 in one embodiment of the present invention, and the actual basis weight of the recording material. It is a figure which shows the relationship between the voltage value output by the ultrasonic sensor 52 in one Embodiment of this invention, and the actual basis weight of a recording material. It is a graph which shows the relationship between the basis weight of the recording material detected by using the paper thickness sensor 53 in one Embodiment of this invention, and the actual basis weight of the recording material. It is a figure which shows the detection accuracy of each of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 for various recording materials. It is a figure which shows the combination of the transmittance of the recording material in one Embodiment of this invention, and the sensor used for the basis weight detection. It is a figure which shows the method of discriminating the type of the recording material in one Embodiment of this invention. It is a figure which shows typically the setting table in one Embodiment of this invention. It is the first part of the flowchart which shows the operation of the image forming apparatus 1 in one Embodiment of this invention. It is the second part of the flowchart which shows the operation of the image forming apparatus 1 in one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the following embodiment, a case where the recording material discrimination device is mounted on the image forming device will be described. Examples of the image forming apparatus include an MFP, a printer, a copying machine, a facsimile, and the like. Further, the recording material discrimination device may be mounted on a device other than the image forming device such as a recording material accommodating device and 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 each other.

[Structure 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.

With reference to FIG. 1, the image forming apparatus 1 (an example of the recording material discriminating device) in the present embodiment discriminates the type of the recording material, and prints on the recording material under the printing conditions according to the discriminated type of the recording material. On the other hand, printing is performed. The image forming apparatus 1 includes a recording material conveying section 10 (an example of a conveying means), a paper feed tray 11 (an example of an accommodating section), a toner image forming section 20 (an example of a printing means), a fixing device 21, and a power supply. It mainly includes 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 is loaded with and accommodates a recording material M for forming an image. The paper feed 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 cannot be replenished from the outside of the image forming apparatus 1. There may be a plurality of paper feed trays 11.

The recording material transport unit 10 transports the recording material M along the transport path TR. The recording material transport unit 10 includes a paper feed roller 12, a transport roller 13, a resist roller 14, a paper discharge roller 15, and a paper 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 resist roller 14 are provided along the transport path TR. The resist roller 14 includes a metal roller 141 and a rubber roller 142. The paper ejection roller 15 is provided at the most downstream portion of the transport path TR. The paper ejection tray 16 is provided at the uppermost portion 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) by a so-called tandem method, and at the printing position ST, the recording material conveying unit 10 A toner image is formed on the recording material M conveyed by the above. The toner image forming unit 20 includes an intermediate transfer belt 20a. Further, the toner image forming unit 20 includes a photoconductor 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 transporting the recording material carrying the toner image along the transport path TR while grasping the recording material.

The power supply unit 22 supplies electric 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 operation inputs related to the operation of the image forming apparatus 1.

The control unit 40 controls the operation of the entire image forming apparatus 1. The control unit 40 is composed of a CPU (Central Processing Unit) that executes a control program, a ROM (Read Only Memory) that stores a control program, and a RAM (Random Access Memory) that constitutes 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 by different methods under the control of the control unit 40, and the information regarding the detected physical properties is transmitted to the control unit 40. Output. The physical characteristics of the recording material detected by 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 also be used. good. The detection positions of the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53 are on the upstream side of the resist 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 housed in the paper feed tray 11 into the transport path TR one by one by the paper feed roller 12, and prints along the transport path TR by the transport roller 13 and the resist roller 14. Lead to position ST. The image forming apparatus 1 uses the resist roller 14 to temporarily stop the recording material M, and then conveys the recording material M to the printing position ST at 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 a well-known electrophotographic method and a tandem method, and the toner is generated by the rotation of the intermediate transfer belt 20a. The image is conveyed toward the print position ST. The recording material M is sent 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 20a to the recording material M at the printing position ST.

The image forming apparatus 1 heats and pressurizes the recording material M on which the toner image is formed by the fixing apparatus 21. As a result, the toner image is fixed on the recording material M. After that, the image forming apparatus 1 discharges the recording material M to the paper ejection tray 16 by the paper ejection roller 15.

When the image forming apparatus 1 conveys the plurality of recording materials M accommodated in the paper feed tray 11 one by one, the image forming apparatus 1 determines each type 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 conveying 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 preferentially uses a sensor for discriminating 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. Is selected from the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53.

2 to 6 are views showing a partial configuration of an optical sensor 51, an ultrasonic sensor 52, and a paper thickness sensor 53 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the xz plane at the first position in the y-axis direction. FIG. 3 is a cross-sectional view taken along the xz plane at the second position in the y-axis direction. FIG. 4 is a view when the vicinity of the substrate 512 is viewed in the direction from the positive to the negative of the x-axis. FIG. 5 is a view when the vicinity of the substrate 512 is viewed in the direction from positive to negative on the z-axis. FIG. 6 is a perspective view of the vicinity of 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 with the transport path TR interposed therebetween. The two rollers 61 are arranged on the right side of FIG. 2 of the transport path TR. The two rollers 61 are arranged in the y-axis direction. The guide 62 is arranged on the left side of FIG. 2 of the transport path TR. The recording material M fed by the paper feed roller 12 is conveyed in the gap between the two rollers 61 and the guide 62 while the displacement of the recording material M in the thickness direction during transfer is suppressed by the two rollers 61 and the guide 62. It is transported along the route TR.

The optical sensor 51 is an example of a voltage value (an example of information on the transmittance of light transmitted through the recording material M) according to the amount of transmitted light transmitted through the recording material M and at a position along the transport direction of the recording material M. ) Is output. Further, the optical sensor 51 outputs a voltage value according to the amount of reflected light transmitted through the recording material M. The optical sensor 51 includes substrates 511 and 512, light emitting elements 513 and 514, a light receiving element 515, and light guide plates 516 and 517.

The substrate 511 is on the right side of FIG. 2 of the transport path TR, and is arranged between the two rollers 61. The light emitting element 513 is fixed to the surface of the substrate 511 facing the transport path TR side. The substrate 512 is arranged on the left side of FIG. 2 of the transport path TR. 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 side.

The light guide plate 516 is provided on the right side of FIG. 2 of the transport path TR and above the substrate 511. 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. 2 and above the substrate 512. 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 regarding 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 transport path TR from the detection position of the optical sensor 51, and exists on the upstream side of the transport path TR from the resist roller 14. The ultrasonic sensor 52 includes a transmission board 521, a reception board 522, a transmission sensor 523, and a reception sensor 524. The transmission board 521 is arranged on the left side of FIG. 2 of the transport path TR. The substrate 512 and the transmission substrate 521 are arranged in the y-axis direction. The receiving board 522 is on the right side of FIG. 2 of the transport path TR, and is arranged diagonally above the transmitting board 521. The transmission sensor 523 is fixed to the surface of the transmission board 521 facing the transport path TR side. The reception sensor 524 is fixed to the surface of the reception board 522 facing the transport path TR side.

The paper thickness sensor 53 is in contact with the metal roller 141. The metal roller 141 can move in the 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 according to the thickness of the recording material M. The paper thickness sensor 53 includes an actuator 55 (an example of a displacement member) that comes into contact with the metal roller 141, and outputs information regarding the amount of displacement of the actuator 55 when the recording material M passes through the resist roller 14.

[Method of detecting the 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 diagram showing a method of detecting the basis weight of the recording material M using the optical sensor 51 according to the embodiment of the present invention.

With reference to FIG. 7, the control unit 40 includes a source control unit 411, an averaging unit 412, a physical property detection unit 413, and a discrimination unit 414 (first discrimination means, selection means, identity discrimination means, first 2 is included as an example of the discriminating means) and the print condition setting unit 415. The light emitting element 514 records light L3 which is light of each color of R (red), G (green), and B (blue) and becomes reflected light under the control of the source control unit 411. Irradiate M sequentially. 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 reflected light amount 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 by the light receiving element 515. In order to increase the amount of reflected light, a white back plate may be provided on the back surface of the recording material M at the position where the light L3 is irradiated.

The light emitting element 513 is light L1 having characteristics based on the color of the recording material M detected by the physical property detection unit 413 under the control of the source control unit 411, and becomes transmitted light with respect to the recording material M. Irradiate light L1. The light emitting element 513 irradiates the light L1 at a timing different from the light emitting timing of the light emitting element 514. The light receiving element 515 receives the transmitted light L2 (mainly scattered light scattered by the recording material M) transmitted through the recording material M, and is the amount of transmitted light which is the amount of the transmitted light L2 in the transport 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 by 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 discrimination unit 414 discriminates the type of the recording material M by a method described later. In the present embodiment, the discriminating unit 414 discriminates the type of the recording material M from the plain paper, the label paper, and the backing paper. The discriminating unit 414 may discriminate the type of the recording material M from the options including the envelope and the OHP sheet.

As will be described later, the print condition setting unit 415 sets the print conditions according to the type of the discriminated recording material M.

The plain paper is a paper generally used in an image forming apparatus, and neither side of the paper is printed. The label paper is a recording material that includes a material having an adhesive on the back and a mount to 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 on only one side of plain paper. Envelopes are made by stacking paper in a bag shape. The transparency sheet is a transparent film on which an image that is the basis of an image projected by an OHP (overhead projector) is drawn.

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

In order to prevent a decrease in the detection accuracy of the basis weight of the recording material M, the paper passing width (displacement in the thickness direction of the recording material M during transportation) at the detection position of the optical sensor 51 is ± with reference to the position of the transport path TR. It is preferable to set the range from 1 mm to ± 2 mm. Further, the ratio (d1: d2) of the distance d2 from the light emitting element 514 to the recording material M with respect 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 the voltage values obtained at each of the 10 or more detection positions provided at a pitch of 5 mm in the recording material M. The optical sensor 51 is required to have stability in the posture of the recording material M at the detection position, and is required to ensure accuracy for a wide range of light amounts. The optical sensor 51 is preferably arranged near the nip of the intermediate roller.

FIG. 8 is a diagram schematically showing various printing patterns of the backing paper. In addition, in FIGS. 8A to 8C, the voltage value output by the optical sensor 51 when each backing paper is detected is also shown.

With reference to FIG. 8, when the light guide plate 516 is provided, the light L1 can be irradiated over a wide range of the recording material M along the width direction (horizontal direction in FIG. 8). When the light guide plate 517 is provided, the transmitted light L2 from a wide range of the recording material M along the width direction is condensed 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 transmitted light transmitted through the entire region in the direction (width direction) perpendicular to the transport direction of the recording material M. As a result, in addition to the backing paper having a print pattern (“*” mark or hatched portion) on the center line P1 in the width direction of the recording material M as shown in FIGS. 8 (a) and 8 (b), FIG. The backing paper having a print pattern on a portion other than the center line P1 as shown in 8 (c) can also be detected by using the optical sensor 51.

When the recording material M is the backing paper, the voltage value of the optical sensor 51 drops significantly at the printed 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. When the fluctuation amount ΔV is larger than the predetermined amount VA, the discriminating unit 414 may discriminate the recording material M as the backing paper without calculating the average value by the averaging unit 412.

Further, if the backing paper is stored in the paper feed tray 11 before the recording material M is stored in the paper feed tray 11, it is highly possible that the recording material M is also the backing paper. In the discriminating unit 414, when the backing paper is stored in the paper feed tray 11 before the recording material M is stored in the paper feed tray 11, the fluctuation amount ΔV of the voltage value of the optical sensor 51 is a predetermined amount VB (place). When the quantitative VB is larger than the predetermined amount VA), the recording material M may be determined as the backing paper without calculating the mean value by the averaging unit 412.

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

With reference to FIG. 9, the transmission sensor 523 irradiates the recording material M with the ultrasonic wave L11 under the control of the 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 that passes through the recording material M and an ultrasonic wave L13 that is reflected by the recording material M. The reception sensor 524 receives the ultrasonic wave L12 transmitted 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 is a recording material based on the ratio (attenuation rate) of the peak value of the ultrasonic wave amount indicated by the voltage value output from the reception sensor 524 to the peak value of the ultrasonic wave amount transmitted from the transmission sensor 523. Detects the basis weight of M.

The envelope is made of overlapping papers, and has the property that ultrasonic waves are less likely to pass through than plain paper. Therefore, when the ultrasonic wave amount (the ultrasonic wave amount transmitted through the recording material M) indicated by the voltage value output from the receiving sensor 524 is lower than the predetermined super volume wave amount threshold TH, the discriminating unit 414 is used. The recording material M may be discriminated as an envelope regardless of the detection result of the basis weight using the sensor of. In particular, the angle θ formed by the irradiation direction of the ultrasonic wave L11 by the transmission sensor 523 with respect to the transport path TR is preferably 38 degrees or more and 45 degrees or less. In this angle range, the amount of ultrasonic waves decreases remarkably when the recording material is an envelope. Therefore, by adopting this angle range, the detection accuracy of the envelope can be improved.

In order to prevent a decrease in the detection accuracy of the basis weight of the recording material M, it is preferable that the paper passing width at the detection position of the ultrasonic sensor 52 is set to 2.4 mm or less. This is because the recording material M is required to have a stable posture at the detection position of the ultrasonic sensor 52.

FIG. 10 is a diagram 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.

With reference to FIG. 10, the paper thickness sensor 53 includes a sensor unit 54 and an actuator 55. The sensor unit 54 detects the movement amount of the actuator 55, and outputs information indicating the detected movement amount 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 support portions 541 swingably support the actuator 55 between them. The pedestal portion 542 fixes the two support portions 541. The irradiation unit 543 is provided inside one of the support units 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 light from the irradiation unit 543 that has passed through the encoder unit 552. The light receiving unit 544 outputs information according to the amount of received light to the control unit 40.

The actuator 55 can move about 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 that of the low transmittance portion 552b. Each of the plurality of high transmittance portions 552a and each of the plurality of low transmittance portions 552b are alternately arranged along the swing direction of the actuator 55. As a result, the transmittance of the portion of the encoder unit 552 that is irradiated with light from the irradiation unit 543 changes periodically due to the movement of the actuator 55. The arm portion 553 connects the contact portion 551 and the encoder portion 552. As a result, the contact portion 551 and the encoder portion 552 swing integrally. The rotation shaft 554 is fixed near the boundary between the encoder portion 552 and the arm portion 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 one embodiment of the present invention. FIG. 11A is an output of the sensor unit 54 when the actuator 55 moves in the plus direction (arrow SA direction). FIG. 11B is an output of the sensor unit 54 when the actuator 55 moves in the minus direction (arrow SB direction).

With reference to FIG. 11, the light receiving unit 544 outputs two phases, A phase and B phase. Each of the A phase and the B phase is a pulse, and the phase of the actuator 55 in the moving direction (the thickness direction of the recording material M) is shifted by 90 degrees. This makes it possible to measure the thickness with a resolution (accuracy) corresponding to the distance PE between the pulse edges. This resolution is, for example, 5 μm.

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

In order to suppress the wear of the contact portion 551, the contact portion 551 indirectly contacts the recording material M, and the displacement of the metal roller 141 due to the passage of the recording material M is caused by the actuator 55. It is required to be arranged so that it can be accurately transmitted to.

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

[Accuracy of detection 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 by using the optical sensor 51 according to the embodiment of the present invention and the actual basis weight of the recording material.

With reference to FIG. 12, the physical property detection unit 413 stores the curve LN1. The curve LN1 is a change in the reference value of the basis weight according to the transmittance of the light (transmitted light L2) transmitted through the recording material detected by using the optical sensor 51 (hereinafter, may be referred to as the transmittance of the recording material). It is a reference curve on the two-axis coordinates showing. 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 transmitted light transmitted through the recording material. Further, the physical property detection unit 413 detects the basis weight of the recording material by using the curve LN1 based on the transmittance of the detected recording material.

When the recording material is plain paper, the points showing the relationship between the detected transmittance of the recording material and the actual basis weight of the recording material are substantially on the curve LN1. On the other hand, when the recording material is a backing paper, an envelope, or a label paper, the point showing 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 paper 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 the backing paper has a printed portion, which makes it difficult for light to pass through as compared with plain paper. This is because envelopes are made of overlapping paper, which makes it difficult for light to pass through compared to plain paper. When the recording material is label paper, the basis weight obtained from the curve LN1 based on the detected transmittance of the recording material is smaller than the actual basis weight. This is because label paper has a higher specific density than plain paper.

Further, when looking at the detection accuracy of the basis weight detected by using the curve LN1 based on the transmittance, in the range where the transmittance of the light transmitted through the recording material is larger than 8.0% (range RG1). It can be seen that the deviation from the curve LN1 at the point showing 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. In the range where the transmittance of the light transmitted through the recording material is 8.0% or less, the deviation from the curve LN1 at the point indicating the relationship between the transmittance and the actual basis weight of the recording material is large, and it is detected 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 OHP sheet has extremely high light transmittance compared to plain paper, label paper, backing paper, envelopes, etc. (from a predetermined transmittance threshold value). Is also expensive). Therefore, it is possible to detect that the recording material is an OHP sheet by using the optical sensor 51.

FIG. 13 is a diagram showing the relationship between the voltage value output by the ultrasonic sensor 52 according to the embodiment of the present invention and the actual basis weight of the recording material.

With reference to FIG. 13, the physical property detection unit 413 stores the curve LN2. The curve LN2 is a reference curve showing the relationship between the voltage value output by 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 by the ultrasonic sensor 52.

When the recording material is plain paper, label paper, or backing paper, the points indicating the relationship between the voltage value and the actual basis weight of the recording material are substantially on the curve LN2. In particular, when the recording material is a backing paper, the printed portion has almost no effect on ultrasonic waves. On the other hand, when the recording material is an envelope, the point showing 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 by using the curve LN2 based on the voltage value is larger than the actual basis weight. This is because envelopes are made of overlapping paper, which makes it harder for ultrasonic waves to pass through than plain paper.

Further, when looking at the detection accuracy of the basis weight obtained by using the curve LN2 based on the voltage value, in the range where the voltage value is 2.8 V or more (range RG2), the voltage value and the actual basis weight of the recording material are observed. It can be seen that the deviation from the curve LN2 of the point indicating the relationship with the quantity is small, and the detection accuracy of the basis weight detected using the curve LN2 is high. In the range where the voltage value is less than 2.8V, the deviation from the curve LN2 of the point showing 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 high. It turns out to be low. Here, the range where the voltage value is 2.8 V or more corresponds to the range where the light transmittance in the graph of FIG. 12 is 2.8% or more (range RG2).

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

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

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

With reference 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 it has high accuracy in discriminating the OHP sheet. The ultrasonic sensor 52 has high accuracy in detecting the basis weight of thin backing paper (basis weight: 150 g / m ² or less), discriminating label paper, and discriminating envelopes. 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). is doing.

[Method of determining the type of recording material for the first sheet]

As described above, the types of sensors that can detect the basis weight with high accuracy differ depending on the transmittance of the recording material. Therefore, when the discriminating unit 414 conveys a plurality of recording materials one by one by the recording material conveying unit 10 for printing, the type of the first recording material is as follows based on the outputs of the plurality of sensors. It is determined by the method of.

The "first recording material" may be the first recording material transported by the recording material transport unit 10 after the paper feed tray 11 is switched from the open state to the closed state. , It may be the first recording material of the print job.

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

With reference to FIGS. 12 and 16, the transmittance of the recording material detected by the discriminant unit 414 using the optical sensor 51 (transmittance of the recording material indicated by the information output by the optical sensor 51) is 8.0%. When the range is larger than (an example of the first threshold value) RG1, the basis weight of the recording material is calculated based on the output of the optical sensor 51 among the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53. Identify (detect).

When the transmittance of the recording material detected by using the optical sensor 51 is within the range RG2 of 2.8% (an example of the second threshold value) or more and 8.0% or less, the discrimination unit 414 is 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.

When the transmittance of the recording material detected by the optical sensor 51 is within the range RG3 of less than 2.8%, the discrimination unit 414 is among the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53. 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 for discriminating 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.

With reference to FIG. 17, the discriminating unit 414 then discriminates the type of recording material based on the state of deviation of the specified physical properties from the reference value. The discrimination unit 414 plots points (for example, points PT1 to PT3) indicating the transmittance of the recording material and the detected basis weight on the biaxial coordinates. The discriminating unit 414 discriminates the type of recording material from 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 region G1 that does not deviate from the curve LN1 (when the plotted points are, for example, the point PT1), the discriminating unit 414 uses plain paper as the recording material. Determine if there is. This is because when the recording material is plain paper, the actual basis weight is almost the same as the basis weight detected by the optical sensor 51, as shown in FIG.

Further, when the plotted points exist in the region G2 deviating downward from the curve LN1 (when the plotted points are, for example, the point PT2), the discriminating unit 414 has a backing paper as the type of recording material. To determine. This is because when the recording material is a backing paper, the actual basis weight is smaller than the basis weight detected by the optical sensor 51, as shown in FIG.

Further, when the plotted points exist in the region G3 deviated upward from the curve LN1 (when the plotted points are, for example, the point PT3), the discriminating unit 414 uses a label paper as the recording material. To determine. This is because when the recording material is label paper, the actual basis weight is larger than the basis weight detected by the optical sensor 51, as shown in FIG.

[Method of determining the type of recording material for the second and subsequent sheets]

Regarding the types of recording materials for the second and subsequent sheets, the discrimination unit 414 has a sensor among the optical sensor 51, the ultrasonic sensor 52, and the paper thickness sensor 53, based on the discrimination result of the type of the first recording material. Select and preferentially use the selected sensor to determine.

The "second and subsequent recording materials" are recording materials that are conveyed by the recording material conveying unit 10 until the paper feed tray 11 is switched to the open state again after the first recording material is conveyed. It may be the recording material of the second and subsequent sheets of the print job.

The discrimination unit 414 is a sensor used for specifying the basis weight of the first recording material (transmittance of the recording material) as a sensor preferentially used when discriminating the type of the second and subsequent recording materials. Is within the range RG1: optical sensor 51, when the transmittance of the recording material is within the range RG2: ultrasonic sensor 52, when the transmittance of the recording material is within the range RG3: paper thickness sensor 53) is selected. do. The determination unit 414 determines the identity between each type 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 each type of recording material on the second and subsequent sheets and the type of recording material on the first sheet is the basis weight of each of the recording materials on the second and subsequent sheets and the basis weight of the recording material on the first sheet. It may be determined based on the sameness.

When the determination unit 414 determines that the type of the second and subsequent recording materials and the type of the first recording material are different, the determination unit 414 determines the type of the recording material and the type of the first recording material. It is determined based on the outputs of a plurality of sensors in the same manner as in. In this case, it is preferable that the type of the recording material is determined at least based on the output of the optical sensor 51. Further, in this case, the recording material transport unit 10 may reduce the transport speed of the recording material until the discriminating unit 414 determines the type of the recording material, and the toner image forming unit 20 may reduce the transport speed of the recording material. Printing on the recording material may not be started until the type is determined by the discriminating unit 414.

[How to determine printing conditions]

FIG. 18 is a diagram schematically showing a setting table according to an embodiment of the present invention.

With reference to FIG. 18, the print condition setting unit 415 sets the print condition according to the type of the discriminated recording material by using the setting table.

In the setting table, the printing conditions set when the type of the discriminated recording material is plain paper, label paper, backing paper, envelope, and OHP sheet are described. Printing conditions include system speed (printing speed), recording material spacing, transfer current, fixing temperature, fixing pressure separation (press contact state between fixing member and pressure member), FS (Finisher) prohibition (prohibition regarding post-processing). , Double-sided prohibition (prohibition of double-sided printing), and each item of printing direction are included.

If the recording material has a backing paper, double-sided printing is prohibited because there are characters already printed on the back side. If the recording material is label paper, the system speed is switched between medium speed and low speed (a value different from the system speed when the recording material is plain paper (slow value)). By doing so), the fixing heat is efficiently transferred to the recording material.

The printing conditions in FIG. 18 are examples, and the printing conditions set according to the type of recording material are arbitrary. The print condition setting unit 415 sets the system speed when the recording material is determined to be label paper to be different from the printing speed when the recording material is determined to be plain paper (lower than the printing speed when the recording material is determined to be plain paper). Value) is preferably set. Further, it is preferable that the print condition setting unit 415 prohibits double-sided printing when the recording material is determined to be the backing paper, and does not accept the double-sided printing setting 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.

With reference to FIG. 19, the control unit 40 determines whether or not the print request has been accepted (S1). The control unit 40 repeats the process of step S1 until it is determined that the print request has been accepted.

When it is determined in step S1 that the print request has been accepted (YES in S1), the control unit 40 starts feeding the recording material from the paper feed tray 11 (S3), and the resist roller 14 feeds the recording material. Stop (S5). Subsequently, the control unit 40 determines whether or not the recording material being conveyed is the first recording material after being set (replenished) in the recording material in the paper feed tray 11 (S7).

When it is determined in step S7 that the recording material being transported is the first recording material (YES in S7), the control unit 40 performs a type determination process using a plurality of sensors to determine the type of the recording material. (S17). Next, the control unit 40 changes the printing conditions according to the type of the discriminated recording material (S19), and resumes the transport 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 transported is the second and subsequent recording materials (NO in S7), the control unit 40 identifies (detects) the basis weight of the first recording material. The sensor used in the above is used to detect the basis weight of the recording material (S9). Subsequently, the control unit 40 determines whether or not the detected basis weight is the same as the basis weight of the first recording material (S11).

When it is determined in step S11 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 type of the recording material being conveyed for the first sheet. It is determined that the type is the same as that of the material (S13), and the process proceeds to 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 the recording material being conveyed is the first recording material. It is determined that the type is different, and the print timing is delayed (S15). Next, the control unit 40 proceeds to the process of step S17, performs a type discrimination process using a plurality of sensors, and discriminates the type of the recording material (S17). After that, the control unit 40 performs the processing after step S19.

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

With reference to FIG. 20, in the type discrimination process using the plurality of sensors in step S17, the control unit 40 detects the transmittance of the recording material using the optical sensor 51 (S101), and the detected transmittance is 8. It is determined whether or not it is 0% or more (S103).

When it is determined in step S103 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 steps. Proceed to the process of S113.

When it is determined in step S103 that the detected transmittance is less than 8.0% (NO in S103), the control unit 40 determines whether or not the detected transmittance is 2.8% or more (NO). S107).

When 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 by using the ultrasonic sensor 52 (S109). The process proceeds to step S113.

When it is determined in step S107 that the detected transmittance is less than 2.8% (NO in S107), the control unit 40 detects the basis weight of the recording material by 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 or not the position of the point deviates downward from the curve LN1 (S115).

In step S115, when it is determined that the position of the point deviates downward from the curve LN1 (YES in S115), the control unit 40 determines that the recording material is the backing paper (S117), and returns. ..

When 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. (S119).

In step S119, when it is determined that the positions of the points deviate upward from the curve LN1 (YES in S119), the control unit 40 determines that the recording material is the label paper (S121) and returns. ..

In step S119, when it is determined that the positions of the points do 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 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. To. As a result, it is possible to suppress a decrease in the accuracy of discriminating the type of recording material as compared with the case where the type of recording material for the second and subsequent sheets is not discriminated. Further, since it is easy to discriminate the types of recording materials for the second and subsequent sheets, the types of recording materials are discriminated as compared with the case where all the types of recording materials to be transported are discriminated using a plurality of sensors 51. It is possible to shorten the time required for the sensor and prevent the life of the sensor from being shortened.

[others]

The recording material discriminating device of the present invention may discriminate the type of recording material from at least some options of plain paper, label paper, backing paper, envelope, and OHP sheet, or may discriminate the type of recording material. It may be one that detects the basis weight of the recording material without detecting the type.

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

The embodiments described above should be considered exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Image forming device (an example of recording material discrimination device)
1a Image forming apparatus main body 10 Recording material transport unit (example of transport means)
11 Paper tray (example of accommodating unit)
12 Paper feed roller 13 Conveyor roller 14 Resist roller 15 Paper output roller 16 Paper output tray 20 Toner image forming unit (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 Part 412 Averager part 413 Physical property detection part 414 Discrimination part (Example of first discriminating means, selection means, identity discriminating means, second discriminating means)
415 Printing condition setting part 511,512 Board 513,514 Light emitting element 515 Light receiving element 516,517 Light guide plate 521 Transmitting board 522 Receiving board 523 Transmitting sensor 524 Receiving sensor 541 Support part 542 Pedestal part 543 Irradiation part 544 Light receiving part 551 Contact part 552 Encoder part 552a High transmittance part 552b Low transmittance part 555 Arm part 554 Rotation axis AR1 Metal roller movement direction G1, G2, G3 2-axis coordinate area L1, L3 Light L2 Transmitted light L4 Reflected light L11, L12, L13 Super Sound LN1 Reference curve on biaxial coordinates showing the change in the reference value of the basis weight according to the transmittance of the light (light L1) transmitted through the recording material detected by the first physical property detecting means. Output by the LN2 ultrasonic sensor. Reference curve showing the relationship between the voltage value to be applied and the actual basis weight of the recording material M Recording material P1 Center line PE Distance between pulse edges PT1, PT2, PT3 Points on 2-axis coordinates RG1, RG2, RG3 Light transmission Range of rate SA, SB Actuator movement direction ST Printing position TR Transport path

Claims (14)

A transport means for transporting recording materials and
Each of the multiple sensors that output information on the physical characteristics of the recording material detected by different methods,
First, when a plurality of recording materials are transported one by one by the transport means, the type of the first recording material transported by the transport means is determined based on the outputs of the plurality of sensors. Discrimination means and
Based on the determination result of the type of the first recording material by the first determining means, it is preferentially used when determining the type of the second and subsequent recording materials conveyed by the conveying means. A recording material discriminating device including a selection means for selecting a sensor from the plurality of sensors. Identity between the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means and the type of the first recording material determined by the first determination means. Identity determination means to determine
When the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means is different from the type of the first recording material determined by the first determination means. The first aspect of the present invention further comprises a second discriminating means for discriminating the type of the second and subsequent recording materials based on the outputs of the plurality of sensors when discriminating by the identity discriminating means. The recording material discrimination device described. The transport means is the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means, and the first recording material determined by the first determination means. When the identity discriminating means determines that the types are different, the second and subsequent recording materials are conveyed until the type of the second and subsequent recording materials is determined by the second discriminating means. The recording material discrimination device according to claim 2, which reduces the speed. A printing means for printing on the recording material conveyed by the conveying means is further provided.
The transport means includes a resist roller that transports a recording material to a printing position by the printing means in accordance with the timing of printing by the printing means.
The recording material discrimination apparatus according to claim 1, wherein the detection position of each of the plurality of sensors is on the upstream side of the resist roller along the transport path of the recording material. Identity between the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means and the type of the first recording material determined by the first determination means. Identity determination means to determine
When the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means is different from the type of the first recording material determined by the first determination means. 4. The fourth aspect of the present invention further comprises a second discriminating means for discriminating the type of the second and subsequent recording materials based on the outputs of the plurality of sensors when discriminating by the identity discriminating means. The recording material discrimination device described. The transport means is the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means, and the first recording material determined by the first determination means. When the identity discriminating means determines that the types are different, the second and subsequent recording materials are conveyed until the type of the second and subsequent recording materials is determined by the second discriminating means. The recording material discriminating device according to claim 5 , which reduces the speed. The printing means includes the type of the second and subsequent recording materials determined based on the output of the sensor selected by the selection means, and the first recording material determined by the first determination means. When the identity discriminating means determines that the types are 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 discriminating means. The recording material discriminating device according to claim 5 or 6 , which does not start. The plurality of sensors include an optical sensor that outputs information regarding the transmittance of light transmitted through the recording material.
The recording material discriminating device according to any one of claims 5 to 7 , wherein the second discriminating means discriminates the type of the second and subsequent recording materials based on at least the output of the optical sensor. The plurality of sensors
An optical sensor that outputs information about the transmittance of light that passes through the recording material,
Includes an ultrasonic sensor that outputs information about the transmittance of ultrasonic waves that pass through the recording material.
The first discriminating 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 value, the physical properties of the first recording material are determined 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 within the range smaller than the first threshold value and larger than the second threshold value, the ultrasonic wave is specified. Specific means for identifying the physical properties of the first recording material based on the output of the sensor, and
The invention according to any one of claims 1 to 8 , further comprising a deviation determination means for determining the type of the first recording material based on the state of deviation of the physical properties specified by the specific means from the reference value. Recording material discrimination device. The plurality of sensors further include a paper thickness sensor that outputs information regarding the amount of displacement of the displacement member as the recording material passes through the detection position of the displacement member.
When the transmittance of the first recording material indicated by the information output by the optical sensor is smaller than the second threshold value, the specific means is based on the output of the paper thickness sensor. The recording material discriminating device according to claim 9 , which specifies the physical properties of the recording material of the eyes. The recording material discrimination according to claim 9 or 10 , wherein the selection means selects a sensor used by the specific means for specifying the physical properties of the first recording material as the sensor to be preferentially used. Device. The first discriminating means plots points indicating the transmittance of the first recording material indicated by the information output by the optical sensor and the physical properties specified by the specific means on biaxial coordinates. Including more plotting means,
The deviation determining means is based on the state of deviation from the reference curve on the two-axis coordinates indicating the change of the reference value according to the change of the transmittance of the recording material at the points plotted by the plotting means. The recording material discriminating device according to any one of claims 9 to 11 , which discriminates the type of the recording material. Between the open state in which the recording material is accommodated and the recording material can be replenished from the outside of the recording material discriminating device and the closed state in which the recording material cannot be replenished from the outside of the recording material discriminating device. Further equipped with a switchable housing
The first recording material is the first recording material to be conveyed by the conveying means after the accommodating portion is switched from the open state to the closed state.
The second and subsequent recording materials are recording materials that are conveyed by the conveying means until the accommodating portion is switched to the open state again after the first recording material is conveyed . The recording material discriminating device according to any one of. It is a control method of a recording material discriminating device including a transporting means for transporting recording materials and each of a plurality of sensors that output information on the physical properties of recording materials detected by different methods.
First, when a plurality of recording materials are transported one by one by the transport means, the type of the first recording material transported by the transport means is determined based on the outputs of the plurality of sensors. Discrimination step and
Based on the determination result of the type of the first recording material by the first determination step, it is preferentially used when determining the type of the second and subsequent recording materials conveyed by the conveying means. A control method for a recording material discriminating device, comprising a selection step of selecting a sensor from the plurality of sensors.

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