Calibration device

Abstract

To provide a calibration device capable of stabilizing measurement accuracy of a reference value of an optical sensor.SOLUTION: A calibration device for calibrating a reference value of an optical sensor configured to measure characteristics of recording media on a conveying path is provided, the calibration device comprising a rotating unit configured to rotate between a calibration position for calibrating the reference value and a retracted position away from the calibration position using driving force from a drive source, and a switching unit configured to switch the transmission state of the driving force from the drive source to the rotating unit according to a rotation position of the rotating unit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a calibration device. [Background technology]

[0002] In image forming devices, since fixing conditions and the like differ depending on the type of recording medium, settings must be made according to the type of recording medium. In recent years, there have been image forming devices that use sensors to automatically measure the characteristics of the recording medium and change settings accordingly. A known sensor for measuring the characteristics of the recording medium is an optical sensor that irradiates light onto the recording medium, measures the amount of reflected light, and calculates the characteristics of the recording medium (such as moisture content and surface condition).

[0003] The characteristics of a recording medium are calculated using the ratio or difference of the light intensity value from a reference value. The reference value is a measurement value based on a light intensity reference plate that can be placed in the optical path of the optical sensor's light source. If the reference value fluctuates due to factors other than fluctuations in the characteristics of the recording medium, such as changes in electrical components over time or temperature characteristics, it will have a negative impact on the calculation of the characteristics of the recording medium. Therefore, in order to measure the characteristics of the recording medium with high accuracy, it is necessary to calibrate the reference value frequently.

[0004] A light quantity reference plate is known that is configured to be rotatable between a calibration position where it is placed on the optical path of the light source of the optical sensor and a retracted position where it is retracted from the calibration position (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-190420 Summary of the Invention [Problem to be solved by the invention]

[0006] However, because the light quantity reference plate rotates only between the calibration position and the retracted position, the meshing position of the transmission gear that transmits driving force to the light quantity reference plate does not change during the series of rotations required for calibration of the reference value. Therefore, if the reference value is calibrated frequently, the same gear teeth will be used continuously, which makes the transmission gear more susceptible to wear due to long-term and repeated use. Wear on the transmission gear causes variations in the attitude and position of the light quantity reference plate, which can lead to a deterioration in the accuracy of measuring the characteristics of the recording medium.

[0007] An object of the present invention is to provide a calibration device that can stabilize the measurement accuracy of the reference value of an optical sensor. [Means for solving the problem]

[0008] The calibration device according to the present invention comprises: A calibration device for a reference value of an optical sensor that measures characteristics of a recording medium on a conveyance path, comprising: a rotation unit that rotates within a range between a calibration position for calibrating the reference value and a retracted position retracted from the calibration position by a driving force from a driving source; a switching unit that switches a transmission state of a driving force from the driving source to the rotating unit based on a rotation position of the rotating unit; Equipped with. [Effects of the Invention]

[0009] According to the present invention, it is possible to stabilize the measurement accuracy of the reference value of the optical sensor. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an image forming system including a calibration device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of a measuring device. [Figure 3] This is a view of the housing as seen from the + side in the Z direction. [Figure 4] FIG. [Figure 5] FIG. 10 is a view of the calibration unit as seen from the negative side in the Z direction. [Figure 6A] 10A and 10B are diagrams for explaining the restriction of rotation of the rotating member at the calibration position. [Figure 6B] 10A and 10B are diagrams for explaining the restriction of rotation of the rotating member in the retracted position. [Figure 7] 10A and 10B are diagrams illustrating an engagement state of a transmission part in a calibration part. [Figure 8] 1 is a cross-sectional view showing the configuration of a measurement device in which a calibration unit is set as a calibration position. [Figure 9] FIG. 10 is a diagram showing the transition of meshing positions in a transmission unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Fig. 1 is a block diagram showing an image forming system 1 including a calibration device according to an embodiment of the present invention.

[0012] In describing the structure of the calibration device of this embodiment, a Cartesian coordinate system (X, Y, Z) is used. The same Cartesian coordinate system (X, Y, Z) is used in the drawings that will be described later. The X direction indicates the transport direction of the recording medium transported by the calibration device, the Y direction indicates a direction parallel to the recording medium transported by the calibration device and perpendicular to the transport direction (the width direction of the recording medium), and the Z direction indicates the up-down direction of the calibration device.

[0013] 1, image forming system 1 is a system that can measure the characteristics of a recording medium (described later) and change the settings of image forming conditions in accordance with the characteristics of the recording medium to form an image. Image forming system 1 has a paper feed device 10, an image forming device 20, and a measurement device 30.

[0014] The paper feed device 10 has, for example, multiple paper feed units inside, and feeds recording media one by one to the image forming device 20. The paper feed units store recording media identified based on basis weight, size, etc.

[0015] The image forming apparatus 20 is, for example, an intermediate transfer type color image forming apparatus that uses electrophotographic process technology. Specifically, the image forming apparatus 20 primarily transfers toner images of each color (Yellow, M, C, and K) formed on a photosensitive drum onto an intermediate transfer belt, and then superimposes the four color toner images on the intermediate transfer belt, and then secondarily transfers the images onto paper S sent from a paper feed tray unit, thereby forming an image. Note that the image forming apparatus 20 may be an image forming apparatus other than an intermediate transfer type.

[0016] The image forming apparatus 20 includes an image forming section 21, a fixing section 22, a conveying section 23, a control section 24, and the like.

[0017] The control unit 24 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The CPU reads out a program corresponding to the processing content from the ROM, loads it into the RAM, and centrally controls the operations of each block of the image forming apparatus 20 in cooperation with the loaded program.

[0018] The image forming unit 21 forms an image (toner image) on the recording medium fed from the paper feed device 10. The image forming unit 21 has image forming units for forming images using color toners of Y, M, C, and K components, an intermediate transfer unit, and the like.

[0019] The fixing unit 22 fixes the toner image onto the recording medium by applying heat and pressure to the recording medium, onto which the toner image has been transferred, in a fixing nip.

[0020] The conveying unit 23 includes a conveying path, a paper discharge unit, etc. The conveying path includes a plurality of conveying roller pairs such as a registration roller pair, and a normal conveying path that passes the recording medium through the image forming unit 21 and the fixing unit 22 and discharges it outside the image forming apparatus 20.

[0021] The recording media housed in the paper feeder 10 are fed one by one from the top and transported to the image forming device 20 via the measuring device 30. The recording media transported to the image forming device 20 are transported to the image forming unit 21 by a transport path unit. In the image forming unit 21, the toner image on the intermediate transfer belt is secondarily transferred all at once onto one side of the recording media, and a fixing process is carried out in the fixing unit 22. The recording media on which the image has been formed are discharged outside the machine by a paper discharge unit equipped with a paper discharge roller.

[0022] The measuring device 30 is disposed between the paper feed device 10 and the image forming device 20, and has a transport path 30A that connects the recording medium outlet of the paper feed device 10 with the inlet of the transport path section of the image forming device 20. The transport path 30A is provided with two transport rollers 30B aligned in the X direction. The measuring device 30 is configured to be able to measure the characteristics of the recording medium fed from the paper feed device 10 to the transport path 30A.

[0023] The characteristics of the recording medium are, for example, the moisture content (moisture content) of the recording medium and the surface condition of the recording medium. In this embodiment, the characteristics of the recording medium are the moisture content of the recording medium P.

[0024] The measuring device 30 feeds back information about the measured characteristics of the recording medium to the image forming device 20 via a communication unit (not shown). As a result, the image forming device 20 sets process parameters for the image formation conditions (fixing temperature, etc.) in accordance with the information about the characteristics of the recording medium.

[0025] As shown in FIG. 2, the measurement device 30 includes a control unit 31, a housing 32, a measurement unit 33, and a calibration unit .

[0026] The control unit 31 includes a CPU, a ROM, a RAM, etc. The CPU reads out a program corresponding to the processing content from the ROM, loads it into the RAM, and centrally controls the operations of each block of the measurement device 30 in cooperation with the loaded program.

[0027] The housing 32 is made of, for example, resin, and is disposed opposite the transport path 30A in the Z direction. The housing 32 is provided with a measurement unit 33 and a calibration unit .

[0028] The housing 32 is located between the two transport rollers 30B (see FIG. 3). The housing 32 has a first section 321 and a second section 322.

[0029] The first section 321 is a section facing the transport path 30A, and is configured in a box shape that is open on the negative side in the Z direction. Light from the measurement section 33 is emitted toward the recording medium P on the transport path 30A through the opening of the first section 321, and the reflected light from the recording medium P returns to the inside of the housing 32.

[0030] Further, at the upper end of the first section 321, there is provided an arrangement section 321A on which a light receiving section of the measuring section 33, which will be described later, is arranged.

[0031] The second section 322 is arranged on the negative side in the X direction (upstream in the conveying direction) of the arrangement section 321A at the positive end of the Z direction of the first section 321, and extends from the positive end in the Z direction toward the negative side in the X direction and the positive side in the Z direction. The negative end of the second section 322 in the Z direction is provided with an arrangement section 322A on which a light source section 331 of the measurement section 33, which will be described later, is arranged.

[0032] The measuring unit 33 is an optical sensor that measures the characteristics of the recording medium P, and has a light source unit 331 and a light receiving unit 332. The light source unit 331 has a light source board 331A that is arranged in the arrangement unit 322A of the second unit 322. A first light source 331B and a second light source 331C are provided on the light source board 331A. The first light source 331B and the second light source 331C emit light under the control of the control unit 31.

[0033] The first light source 331B is an LED chip that corresponds to a wavelength absorbed by water (for example, 1450 nm), and the second light source 331C is an LED chip that corresponds to a wavelength not absorbed by water (for example, 1300 nm).

[0034] 3, the first light source 331B and the second light source 331C are arranged side by side in the Y direction (the width direction of the recording medium P). In other words, the light sources are arranged side by side in a direction parallel to the conveying surface of the recording medium P on the conveying path 30A and perpendicular to the conveying direction of the recording medium P.

[0035] The light receiving section 332 has a substrate 332A and a light receiving element 332B arranged in the arrangement section 321A of the first section 321. The light receiving element 332B is, for example, a photodiode, and is arranged on the negative surface of the substrate 332A in the Z direction.

[0036] 2, a collimator lens 322B and an aperture 322C are provided in the optical path of light from light source unit 331 of second unit 322 in which light source unit 331 is provided. Also, a light-receiving lens 321B is provided on the negative side in the Z direction of light-receiving unit 332 of first unit 321 in which light-receiving unit 332 is provided.

[0037] Light L1 from light source unit 331 becomes approximately parallel light by collimator lens 322B. Then, the light beam width is restricted by aperture 322C, and light L1 is irradiated onto recording medium P on transport path 30A. Thereafter, scattered reflected light L2 from recording medium P is collected onto light receiving element 332B by light receiving lens 321B. Furthermore, specular reflected light from recording medium P is mainly reflected by the surface of recording medium P, and does not contain information about the moisture content of recording medium P, so it is not received by light receiving unit 332.

[0038] Furthermore, the reflected light corresponding to each of the first light source 331B and the second light source 331C is received by the same light receiving element 332B in a time-division manner. As a result, the moisture content of the recording medium P and its change are measured in real time and fed back to the image forming apparatus 20, and the feedback results are reflected in the image formation conditions, thereby improving the image quality.

[0039] The moisture content of the recording medium P can be calculated based on a reference value measured in advance, for example, in a pre-shipment process of the measuring device 30. The reference value is a value measured by the measuring unit 33 as the amount of light reflected from a light intensity reference plate (made of the same material as the light intensity reference plate described below) placed on the recording medium surface using a jig or the like. The moisture content of the recording medium P is calculated based on the reference value and the amount of light reflected from the recording medium P transported within the measuring device 30. Specifically, the output based on the reference value is set as a moisture content of 0, and the amount of change in the amount of light reflected from the recording medium P from the reference value is calculated as the moisture content of the recording medium P.

[0040] 3, the detection area of ​​the optical sensor on the transport path 30A (the area where the light receiving element 332B is located) is located at a position overlapping with the two transport rollers 30B in the Y direction. Since the position of the recording medium P between the two transport rollers 30B is stable, the position of the recording medium P in the detection area of ​​the optical sensor is stable. As a result, the measurement by the measurement unit 33 can be stabilized.

[0041] Incidentally, the output of the reflected light quantity fluctuates due to changes in electrical components over time, temperature characteristics, etc. When the output of the reflected light quantity fluctuates, the reference value based on the light quantity reference plate also fluctuates. However, if the moisture content of the recording medium P is calculated using a reference value measured in the past, the calculated value will not be accurate due to the fluctuation of the reference value. For this reason, in the measuring device 30, calibration is performed by the calibration unit 34 before the recording medium P reaches the measurement area of ​​the measurement unit 33, such as at the start of a job.

[0042] 4, calibration unit 34 is a part that measures the value of the reflected light amount (reference value) based on a light amount reference plate of the optical sensor in order to calibrate the reference value, and is housed in first part 321 of housing 32. Calibration unit 34 has a drive source 341, a holding part 342, a rotating part 343, a transmission part 344, and a switching part 345. Calibration unit 34, housing 32, and control part 31 correspond to the "calibration device" of the present invention.

[0043] The driving source 341 is a motor having a driving shaft 341A (see FIG. 2). The driving source 341 is fixed on a holding portion 342. The driving source 341 is driven based on a control signal from the control unit 31.

[0044] The holding portion 342 is made of a plate-shaped metal member and holds the rotating portion 343. The holding portion 342 has a main body portion 342A and a pivot support portion 342B.

[0045] The main body 342A is configured in a flat plate shape and is disposed parallel to the XY plane. A hole (not shown) through which the drive shaft 341A of the drive source 341 passes is provided at the end of the main body 342A on the negative side in the X direction. The drive source 341 is fixed onto the main body 342A with the drive shaft 341A passing through this hole.

[0046] Furthermore, the main body 342A is provided with screw holes A1 to A4. The screw holes A1 to A4 are holes through which screws are passed to fix the holding part 342 to the housing 32. Each of the screw holes A1 to A4 fixes the holding part 342 to a fixing part (not shown) of the first part 321 of the housing 32 with a screw.

[0047] The screw hole A1 is located at the end of the body portion 342A on the positive side in the X direction.

[0048] Screw hole A2 is located on the negative side in the X direction of screw hole A1 and on the positive side in the X direction of drive source 341. Screw hole A3 is located at the negative end of main body 342A in the X direction and on the positive side in the Y direction of drive source 341. Screw hole A4 is located at the negative end of main body 342A in the X direction and on the negative end of drive source 341 in the Y direction.

[0049] 5, the screw holes A2, A3, and A4 are positioned so as to surround the driving source 341. In other words, the holding portion 342 is fixed to the housing 32 at multiple points surrounding the driving source 341. Furthermore, the holding portion 342 may be fixed to the housing 32 at at least one of the multiple points so that the housing 32 is sandwiched between the head of the screw and the holding portion 342.

[0050] 4, a rectangular restriction hole A5 is provided in the main body 342A at a position on the positive side in the Y direction of the screw hole A1. The restriction hole A5 is a hole that comes into contact with the rotating part 343 positioned at a calibration position (described later) to restrict rotation of the rotating part 343 toward the negative side in the Z direction. In other words, the restriction hole A5 restricts rotation of the rotating member 343B downstream of the calibration position in the direction from the retracted position toward the calibration position. The restriction hole A5 corresponds to the "first restriction part" of the present invention.

[0051] Furthermore, restricting portions A6 and A7 are provided at the end of the main body portion 342A on the positive side in the Y direction. The restricting portions A6 and A7 protrude from the main body portion 342A on the positive side in the Y direction and are provided at positions corresponding to both ends of the rotating portion 343 in the X direction. The restricting portions A6 and A7 restrict rotation of the rotating portion 343 toward the negative side in the Y direction by coming into contact with the rotating portion 343 positioned in a retracted position described below. In other words, the restricting portions A6 and A7 restrict rotation of the rotating member 343B downstream of the retracted position in the direction from the calibration position toward the retracted position. The restricting portions A6 and A7 correspond to the "second restricting portion" of the present invention.

[0052] The pivot support portion 342B is a portion that pivotally supports the pivot portion 343 so that the pivot portion 343 can pivot, and is formed by bending both ends of the main body portion 342A in the X direction.

[0053] The rotating unit 343 is used to calibrate the reference value of the optical sensor, and has a rotating shaft 343A and a rotating member 343B. The rotating shaft 343A is rotatably supported by the pivot support 342B of the holding unit 342, and is disposed parallel to the X direction.

[0054] The rotating member 343B is a resin member formed in a rectangular plate shape. The rotating member 343B is provided with attachment portions 343C that are attached to the rotating shaft 343A. The attachment portions 343C are formed in a cylindrical shape and are provided at positions corresponding to both ends of the rotating member 343B in the X direction. By being attached to the rotating shaft 343A by the attachment portions 343C, the rotating member 343B rotates around the rotating shaft 343A.

[0055] Of the two mounting portions 343C, the mounting portion 343C on the positive X-direction side is provided at a position corresponding to the above-mentioned restriction hole A5. The mounting portion 343C on the positive X-direction side is provided with a contact portion 343D that protrudes to the positive Z-direction side when the rotating member 343B is arranged parallel to the XY plane.

[0056] 6A, the contact portion 343D comes into contact with the wall surface on the positive side in the Y direction of the restriction hole A5, thereby restricting the rotation of the rotation member 343B toward the negative side in the Z direction when the rotation member 343B is placed in a position parallel to the XY plane (a calibration position described later).

[0057] Furthermore, a metal plate D1 is fixed with a screw to the portion of the contact portion 343D that contacts the wall surface of the restriction hole A5, thereby preventing the contact portion 343D from wearing out even if the contact portion 343D repeatedly contacts the wall surface of the restriction hole A5.

[0058] Furthermore, when the rotating member 343B is arranged parallel to the XY plane, a light quantity reference plate 343E is attached to the surface of the rotating member 343B. The light quantity reference plate 343E is made of the same material as the light quantity reference plate used when measuring a reference value (initial reference value) measured in advance, for example, in a pre-shipment process.

[0059] 6B, when the rotating member 343B is arranged so that its tip faces the positive side in the Z direction, it comes into contact with the restricting portions A6 and A7 of the holding portion 342. As a result, when the rotating member 343B is arranged so that its tip faces the positive side in the Z direction, the rotating member 343B is restricted from rotating toward the negative side in the Y direction.

[0060] The rotating member 343B configured in this manner is configured to rotate within a range between the calibration position and the retracted position, and cannot rotate to positions outside this range.

[0061] The calibration position is a position for calibrating the reference value of the optical sensor, and is a position on the optical path of the light output from the light source unit 331. In this embodiment, the calibration position is a position where the rotating member 343B is arranged so as to be parallel to the XY plane.

[0062] The retracted position is a position retracted from the calibration position and is a position out of the optical path of the light output from the light source unit 331. In this embodiment, the retracted position is a position where the rotating member 343B is arranged so that the tip thereof faces the positive side in the Z direction.

[0063] 5 and 7, transmission unit 344 is a gear mechanism, such as a worm gear, that transmits the driving force of drive source 341 to rotating unit 343. Worm 344A is provided on drive shaft 341A of drive source 341, and worm wheel 344B is provided on rotating shaft 343A. When drive source 341 is driven, the driving force is transmitted to rotating unit 343 via transmission unit 344, causing rotating member 343B to rotate.

[0064] The rotating member 343B is located at the calibration position when calibrating the reference value of the optical sensor, and is located at the retracted position when image formation is performed by the image forming apparatus 20. As shown in FIG. 8, when the rotating member 343B is located at the calibration position, light L1 from the light source unit 331 hits the light quantity reference plate 343E of the rotating member 343B, and the reflected light L4 is received by the light receiving unit 332. The reference value is calibrated based on the amount of reflected light received by the light receiving unit 332. The reference value is stored in a storage device (not shown), and when the reference value is calibrated, the reference value stored in the storage device is updated.

[0065] 2, light L1 from the light source unit 331 strikes the recording medium P on the transport path 30A, and the reflected light L2 is received by the light receiving unit 332. At this time, the moisture content of the recording medium P is calculated using the reference value stored in the storage device.

[0066] 5 and 7, the switching unit 345 is, for example, a torque limiter, and switches between transmitting and not transmitting the driving force by restricting rotation using the restricting hole A5 and the restricting units A6 and A7. The switching unit 345 is provided on the rotating shaft 343A. The rotating shaft 343A is configured so that the portion where the rotating member 343B is disposed and the portion where the worm wheel 344B is disposed can be switched between a connected state and a disconnected state by the switching unit 345. In other words, the switching unit 345 is configured so as to be able to switch between transmitting and not transmitting the driving force of the driving source 341.

[0067] Specifically, the switching unit 345 switches the state of transmission of the driving force from the driving source 341 to the rotating unit 343 based on the rotation position of the rotating member 343B.

[0068] For example, when the rotating member 343B is located within a range between the calibration position and the retracted position, the switching unit 345 transmits the driving force of the driving source 341 to the rotating unit 343. When the rotating member 343B is located at the calibration position or the retracted position, the switching unit 345 cuts off the transmission of the driving force of the driving source 341 to the rotating unit 343.

[0069] In this embodiment, when the rotating member 343B attempts to rotate toward the negative side in the Z direction from the calibration position, the restricting hole A5 and the abutting portion 343D come into contact with each other, causing the torque to become relatively large. As a result, the switching portion 345, which is a torque limiter, blocks the transmission of the driving force of the drive source 341 to the rotating portion 343. Furthermore, when the rotating member 343B attempts to rotate toward the negative side in the Y direction from the retracted position, the restricting portions A6 and A7 come into contact with the rotating member 343B, causing the torque to become relatively large. As a result, the switching portion 345, which is a torque limiter, blocks the transmission of the driving force of the drive source 341 to the rotating portion 343.

[0070] In this embodiment, the control unit 31 controls the drive amount of the drive source 341 so that the rotation amount of the rotating member 343B exceeds the range between the calibration position and the retracted position in a predetermined case. The predetermined case is at least one of the case where the rotating member 343B rotates from the calibration position to the retracted position and the case where the rotating member 343B rotates from the retracted position to the calibration position.

[0071] Specifically, the control unit 31 controls the drive amount of the drive source 341 so that a first drive amount when rotating the rotating member 343B from the retracted position toward the calibration position is different from a second drive amount when rotating the rotating member 343B from the calibration position toward the retracted position.

[0072] For example, the rotation angle between the calibration position and the retracted position is 90 degrees, but control unit 31 controls the drive amount of drive source 341 by setting the rotation angle corresponding to the first drive amount to 150 degrees and the rotation angle corresponding to the second drive amount to 90 degrees. Because the difference between 150 degrees and 90 degrees is 60 degrees, an extra drive force of at least 60 degrees is applied to rotating member 343B during rotation from the retracted position to the calibration position. In this case, the drive force of 60 degrees is restricted by the contact between restriction hole A5 and contact portion 343D.

[0073] For example, as shown in Fig. 9, when the rotating member 343B is located at the retracted position, the meshing position of the worm wheel 344B with the worm 344A is G1 (state of Fig. 9(A)). Here, when the rotating member 343B rotates from the retracted position to the calibration position, the meshing position of the worm wheel 344B with the worm 344A moves from G1 to G2 (state of Fig. 9(B)).

[0074] Here, for example, in a configuration in which the rotation angles corresponding to the first and second drive amounts are both 90 degrees, the meshing position between the worm 344A and the worm wheel 344B does not change through a series of rotation operations performed by calibrating the reference value. In other words, only the portion of the worm wheel 344B between G1 and G2, which corresponds to the range between the retracted position and the calibration position, meshes with the worm 344A. Therefore, each time calibration is performed, the gear teeth in that portion continue to be used, which makes the worm wheel 344B (transmission gear) more susceptible to wear.

[0075] In contrast, in this embodiment, the rotation angle corresponding to the first drive amount is 150 degrees, so that the restriction hole A5 and the abutment portion 343D abut in the state shown in FIG. 9B. At this time, the switching portion 345 cuts off the transmission of the driving force of the driving source 341 to the rotating member 343B, and the worm wheel 344B rotates an additional 60 degrees while the rotating member 343B remains in the calibration position. As a result, the meshing position of the worm wheel 344B with the worm 344A moves from G2 to G3 (the state shown in FIG. 9C).

[0076] Then, when the rotating member 343B rotates from the calibration position to the retracted position again, the angle corresponding to the second drive amount is 90 degrees, so the meshing position of the worm wheel 344B with the worm 344A moves from G3 to G4 (state of (D) in Figure 9).

[0077] As a result, when the worm wheel 344B is in the retracted position, the meshing position between the worm wheel 344B and the worm 344A shifts from G1 to G4. As this rotational movement is repeated, the meshing position gradually shifts.

[0078] As a result, it is possible to prevent the same gear teeth on the worm wheel 344B from being used repeatedly, and therefore it is possible to prevent the transmission gear from becoming easily worn out due to long-term and repeated use.

[0079] 9, the rotation angle corresponding to the first drive amount is set to be larger than the rotation angle corresponding to the second drive amount, but the rotation angle corresponding to the second drive amount may be set to be larger than the angle corresponding to the first drive amount. Also, in the example shown in FIG. 9, the angle corresponding to the second drive amount is set to 90 degrees (the angle of the rotation range of the rotating member 343B), but it may be set to be larger than the angle of the rotation range.

[0080] Furthermore, the absolute value of the difference between the rotation angle of the rotation member 343B based on the first drive amount and the rotation angle of the rotation member 343B based on the second drive amount may be a number other than a divisor of 360 degrees.

[0081] For example, suppose the rotation angle based on the first drive amount is set to 162.6 degrees and the rotation angle based on the second drive amount is set to 156 degrees. In this case, the absolute value of the difference between the rotation angle based on the first drive amount and the rotation angle based on the second drive amount is 6.6 degrees. In other words, the meshing position at the end of a series of rotational movements is shifted by 6.6 degrees from the meshing position at the start of the rotational movements.

[0082] Since 6.6 degrees is a number that is not a divisor of 360 degrees, even if a series of rotational movements is repeated, the transmission gear will not return to the initial meshing position, and the gear teeth of the transmission gear can be used evenly all around.

[0083] Furthermore, since the switching portion 345 is a torque limiter, the rotation of the rotating member 343B is restricted by the holding portion 342, and the transmission of the driving force of the driving source 341 can be easily interrupted.

[0084] In the present embodiment configured as described above, it is possible to prevent the same gear teeth on the worm wheel 344B from being used repeatedly, thereby preventing the worm wheel 344B from becoming easily worn due to long-term and repeated use.

[0085] As a result, variations in the attitude and position of the light quantity reference plate are reduced, making it possible to stabilize the measurement accuracy of the reference value of the optical sensor, and ultimately to stabilize the measurement accuracy of the characteristics of the recording medium P.

[0086] Furthermore, because the transmission unit 344 is configured with a worm gear having a worm 344A and a worm wheel 344B, meshing is smoother than with gears having spur teeth, which makes it possible to smoothly start the movement of the transmission unit 344 and to smoothly switch the drive.

[0087] Furthermore, since the holding portion 342 is fixed to the housing 32 at multiple points surrounding the driving source 341, it is possible to reduce the influence of vibrations in the Z direction caused by the driving of the driving source 341 during rotation.

[0088] Alternatively, the retaining portion 342 may be made of metal and may be fixed to the housing 32 at at least one of the multiple points so that the housing 32 is sandwiched between the head of the screw and the retaining portion 342. This allows the retaining portion 342, which is made of metal, to engage with the screw and be fixed, so that the retaining portion 342 can be firmly fixed even when the housing 32 is made of resin.

[0089] Furthermore, since the metal plate D1 is fixed to the contact portion 343D that contacts the restriction hole A5, the impact and wear caused by contact with the restriction hole A5 can be reduced, and thus the change in posture of the rotating member 343B (light quantity reference plate 343E) can be reduced.

[0090] Furthermore, the rotating member 343B rotates in the X direction, that is, on a rotating shaft 343A parallel to the optical axis. Therefore, when the rotating member 343B is located at the retracted position, the rotating member 343B can be positioned so as not to intersect with the optical axis, which makes it possible to prevent, for example, specularly reflected light or the like from being reflected by the rotating member 343B and received by the light receiving unit 332. As a result, it is possible to prevent a deterioration in the measurement accuracy of the optical sensor.

[0091] The light sources are arranged in a direction parallel to the recording medium P on the transport path 30A and perpendicular to the transport direction of the recording medium P (Y direction). Since the recording medium P is transported sandwiched between two transport rollers 30B lined up in the transport direction, there is a possibility that the recording medium P may experience posture fluctuations such as waving or tilting in the transport direction. In this embodiment, since the two light sources are lined up in the Y direction, the optical path lengths to the light receiving unit 332 between the two light sources can be made approximately the same. As a result, the impact on the output of the light receiving element 332B caused by posture fluctuations of the recording medium P during transport can be reduced.

[0092] Furthermore, because the rotation axis 343A is parallel to the transport direction (X direction) of the recording medium P, it can be easily placed between the two transport rollers 30B, making it possible to make the entire device compact. Also, because it is easy to narrow the distance between the two transport rollers 30B, even small-sized recording media P can be measured while sandwiched between the two transport rollers 30B.

[0093] Furthermore, since the detection area of ​​the optical sensor is positioned so as to overlap with the two transport rollers 30B in the Y direction, the posture of the transported recording medium P on the detection area can be measured in a stable state.

[0094] In the above embodiment, the switching unit 345 is a torque limiter, but the present invention is not limited to this and may be, for example, a clutch such as an electromagnetic clutch. In this case, the control unit 31 may control the switching unit 345 to switch between transmitting and not transmitting the driving force based on the position of the rotating member 343B.

[0095] Furthermore, in the above embodiment, the calibration device has a control unit 31, but the present invention is not limited to this, and for example, the drive source, etc. may be controlled by an external control unit (control unit 24 of the image forming device 20).

[0096] Furthermore, in the above embodiment, the transmission part 344 is a worm gear, but the present invention is not limited to this, and a gear mechanism other than a worm gear may also be used.

[0097] Furthermore, in the above embodiment, the driving source 341 is provided in the calibration unit 34, but the present invention is not limited to this, and the driving force of an external driving source may be transmitted to the rotating unit via an external transmission mechanism or the like.

[0098] Furthermore, in the above embodiment, the metal plate D1 is provided on the contact portion 344D, but the present invention is not limited to this, and the metal plate D1 does not have to be provided.

[0099] Furthermore, in the above embodiment, no metal member is provided at the portion of the rotating member 343B that abuts against the restricting portions A6 and A7, but the present invention is not limited to this, and a metal member may be provided.

[0100] In the above embodiment, the calibration device is provided in the measuring device 30 provided separately from the image forming device 20, but the present invention is not limited to this, and for example, the calibration device (measuring device) may be provided inside the image forming device. In this case, the calibration device may be provided upstream of the image forming unit.

[0101] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be carried out in various forms without departing from the gist or main features thereof. [Explanation of symbols]

[0102] 1. Image forming system 10 Paper feeder 20 Image forming device 21 Image forming unit 22 Fixing section 23 Conveyor 24 Control Unit 30 Measuring Equipment 30A Transport Route 30B Conveyor roller 31 Control Unit 32 Case 33 Measuring part 34 Proofreading Department 321 Part 1 321A Placement 321B Receiving Lens 322 Part 2 322A Placement 322B Collimator Lens 322C Aperture 331 Light source section 331A light source board 331B 1st light source 331C 2nd light source 332 Light receiving part 332A board 332B Photodetector 341 Power Source 341A drive shaft 342 Holding part 342A Main body 342B Axial support 343 Rotating part 343A Rotating shaft 343B Rotating members 343C Mounted part 343D Contact part 343E Light level reference plate 344 Transmission Unit 344A Worm 344B worm wheel 345 Switching section A1 screw hole A2 screw hole A3 screw hole A4 screw hole A5 regulation hole A6 Regulatory Department A7 Regulatory Department D1 Metal plate

Claims

1. A calibration device for a reference value of an optical sensor that measures characteristics of a recording medium on a conveyance path, comprising: a rotation unit that rotates within a range between a calibration position for calibrating the reference value and a retracted position retracted from the calibration position by a driving force from a driving source; a switching unit that switches a transmission state of a driving force from the driving source to the rotating unit based on a rotation position of the rotating unit; A calibration device comprising:

2. The switching unit is When the rotation unit is located within the range, the driving force is transmitted to the rotation unit; When the rotation unit is located at the calibration position or the retracted position, transmission of the driving force to the rotation unit is interrupted. The calibration device of claim 1 .

3. a first restricting portion that restricts rotation of the rotating portion toward a downstream side of the calibration position in a direction from the retracted position toward the calibration position; a second restricting portion that restricts rotation of the rotating portion toward a downstream side of the retracted position in a direction from the calibration position toward the retracted position; Furthermore, the switching unit is a torque limiter that switches between transmission and non-transmission of the driving force by rotation restriction by the first restriction unit and the second restriction unit. The calibration device according to claim 2 .

4. a control unit that controls a drive amount of the drive source so that a rotation amount of the rotation unit exceeds the range when the rotation unit rotates from the calibration position to the retracted position or when the rotation unit rotates from the retracted position to the calibration position, The calibration device according to any one of claims 1 to 3.

5. the control unit controls the drive amount of the drive source so that a first drive amount when the rotation unit is rotated from the retracted position toward the calibration position is different from a second drive amount when the rotation unit is rotated from the calibration position toward the retracted position. The calibration device according to claim 4 .

6. an absolute value of a difference between a rotation angle of the rotation unit based on the first drive amount and a rotation angle of the rotation unit based on the second drive amount is a number other than a divisor of 360 degrees; The calibration device according to claim 5 .

7. the rotating unit has a rotating member on which a light quantity reference plate is arranged, a transmission gear to which a driving force of the driving source is transmitted, and a rotation shaft that rotates the rotating member; the switching unit switches a portion of the rotary shaft where the rotary member is arranged and a portion of the rotary shaft where the transmission gear is arranged between a connected state and a non-connected state. The calibration device of claim 1 .

8. the drive shaft of the drive source has a worm, the transmission gear is a worm wheel that meshes with the worm, The calibration device according to claim 7.

9. a holding portion to which the drive source is fixed and which rotatably holds the rotating portion; a housing to which the holding portion is fixed; Furthermore, the holding portion is fixed to the housing at a plurality of points surrounding the drive source; The calibration device of claim 1 .

10. the retaining portion is made of metal and is fixed to the housing at at least one of the plurality of points so that the housing is sandwiched between a head of a screw and the retaining portion; The calibration device of claim 9.

11. the rotating portion includes a metal member that abuts against at least one of the first restricting portion and the second restricting portion when the rotation of the rotating portion is restricted by the at least one of the first restricting portion and the second restricting portion. The calibration device according to claim 3 .

12. the optical sensor includes a light source and a light receiving unit that receives light from the light source; the rotating unit rotates about a rotation axis parallel to an optical axis of a light source of the optical sensor; The calibration device of claim 1 .

13. a plurality of the light sources are provided side by side in a direction parallel to a conveying surface of the recording medium on the conveying path and perpendicular to the conveying direction of the recording medium; The calibration device of claim 12.

14. the rotating unit rotates about a rotation axis parallel to a transport direction of the recording medium in the transport path; The calibration device of claim 12.

15. the calibration device is disposed at a position between two transport rollers that transport the recording medium in a transport direction of the recording medium on the transport path, a detection area of ​​the optical sensor on the transport path is located at a position overlapping with the two transport rollers in a direction parallel to the recording medium on the transport path and perpendicular to the transport direction of the recording medium; The calibration device of claim 12.

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