JP6171292B2 - Thickness detection apparatus, image forming apparatus, thickness detection method, program, and recording medium - Google Patents

Description

The present invention relates to a thickness detection apparatus , an image forming apparatus, a thickness detection method, a program, and a recording medium .

  Some of the image forming apparatuses and the like that use a recording medium convey the recording medium by rotating the roller with the recording medium sandwiched between two rollers (a pair of rollers). In addition, when using a recording medium such as an image forming apparatus, the thickness of the recording medium is determined when the recording medium is transported in order to determine the type of recording medium or whether a plurality of recording media are transported in an overlapping manner. There is something to detect.

  In Patent Document 1, a conveyance member position variation measuring device (thickness detection device) that detects positional variation of the conveyance member while the conveyance member makes one or more rotations without depending on the rotation period of the conveyance member (roller pair). The technology about is disclosed.

  However, in the technique disclosed in Patent Document 1, when the diameters of the two rollers of the roller pair are different, the thickness of the recording medium may not be detected. That is, in the technique disclosed in Patent Document 1, when the diameters of the two rollers are different, the amount of displacement of the roller that detects the separation distance changes depending on the displacement (or eccentricity) of other rollers. In some cases, the thickness of the recording medium cannot be detected.

  In the technique disclosed in Patent Document 1, there is a case where an error such as noise is included in the detected value of the separation distance (for example, FIG. 3B). That is, in the technique disclosed in Patent Document 1, when the detected value includes an error, the thickness of the recording medium may not be detected.

The present invention detects a separation distance of a roller pair using a period of a displacement amount of the roller pair and a least common multiple of a noise period included in the detection result, and determines the thickness of the recording medium based on the detected separation distance. It is an object to provide a thickness detecting device and a thickness detecting method to be calculated.

According to one aspect of the present invention, the recording medium sandwiched in the gap between the first roller and the second roller is conveyed by rotationally driving the first roller and / or the second roller. A conveying means; a detecting means for detecting a separation distance of the gap; a first period of the first roller; a second period of the second roller; and a period of noise included in a detection result of the detecting means. A calculation unit comprising a cycle calculation unit that calculates a cycle of the least common multiple of the image and a thickness calculation unit that calculates the thickness of the recording medium, and the detection unit is the least common multiple calculated by the cycle calculation unit The detection means detects a plurality of displacements of the separation distance when the recording medium is not sandwiched in the gap and when the recording medium is sandwiched, and the calculation means detects a plurality of displacements detected by the detection means, respectively. Multiple representative points from the amount of displacement And a representative representative point extracting unit that extracts a plurality of corrected representative points, and the representative point and corrected representative point extracting unit divides the amplitudes of the plurality of displacement amounts detected by the detecting unit within a predetermined range. Then, a range having the largest number of feature points extracted in the plurality of divided ranges is selected, the plurality of representative points are extracted in the selected range, and a correction range for enlarging the selected range is designated. Then, the plurality of corrected representative points are extracted in the designated correction range, and the thickness calculating unit is an average value of the plurality of representative points and the plurality of corrected representative points extracted by the representative point and the corrected representative point extracting unit. Is provided, and the calculated average value is used as the thickness of the recording medium.
Further, according to one aspect of the present invention, the first roller and / or the second roller is rotationally driven to be sandwiched between the first roller and the second roller. A detection method for detecting a thickness of a recording medium, the detection step for detecting a separation distance of the gap, the first cycle of the first roller, the second cycle of the second roller, and the detection step. A period calculation step for calculating a period of the least common multiple of the noise period included in the detection result of the above, and a period of the least common multiple calculated in the period calculation step as a detection period when the recording medium is not sandwiched in the gap A reference value detecting step for detecting a plurality of displacement amounts of the separation distance, a displacement amount detection step for detecting a plurality of displacement amounts of the separation distance when the recording medium is sandwiched in the gap, and the reference value The amplitude of a plurality of displacement amounts detected in the output step and the displacement amount detection step is divided into a predetermined range, a range having the largest number of feature points extracted in the plurality of divided ranges is selected, and the selected a representative point extraction step of extracting the representative points of the multiple Te range smell, specify a correction range to expand the scope of the selected correction representative point extraction for extracting the correct representative points of multiple Te correction range odor that the designated Calculating a step, an average value of the plurality of representative points and the plurality of corrected representative points extracted in the representative point extraction step and the corrected representative point extraction step, and calculating the thickness using the calculated average value as the thickness of the recording medium And a thickness detection method characterized by comprising the steps of:

According to the thickness detection apparatus and the thickness detection method of the present invention, the separation distance between the roller pair is detected by using the period of the displacement amount of the roller pair and the least common multiple of the period of the noise included in the detection result. The thickness of the recording medium can be calculated based on the separated distance.

It is a schematic block diagram which shows an example of the thickness detection apparatus which concerns on embodiment of this invention. It is explanatory drawing explaining an example of the detection means of the thickness detection apparatus which concerns on embodiment of this invention. It is explanatory drawing explaining an example of the detection result of the detection means of the thickness detection apparatus which concerns on embodiment of this invention. It is a functional block diagram which shows an example of the function of the thickness detection apparatus which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic external view which shows an example of the thickness detection apparatus which concerns on Example 1 of this invention. It is explanatory drawing explaining an example of the principal part of the detection means of the thickness detection apparatus which concerns on Example 1 of this invention. It is explanatory drawing explaining an example of the detection result of the detection means of the thickness detection apparatus which concerns on Example 1 of this invention. It is a schematic external view which shows an example of the image forming apparatus which concerns on Example 2 of this invention.

  A non-limiting exemplary embodiment of the present invention will be described using a thickness detector that transports a recording medium by a pair of rollers (two rollers). The present invention is not limited to the thickness detection device described below, but includes a medium number detection device, a multifeed detection device, a transport position detection device, an image forming device, an image recording device, a subject machine, a multifunction device, a printer, and a scanner. As long as it uses a plotter, facsimile, fax, or other recording medium (apparatus, equipment, unit, etc.), it can be used. The recording medium from which the thickness detection apparatus according to the present invention can detect the thickness includes plain paper, fine paper, thin paper, cardboard, recording paper and roll paper, as well as an OHP sheet, a synthetic resin film, and a metal. It includes media transported using thin film and other roller pairs.

  In the following description, the same or corresponding members or parts described in all the attached drawings are denoted by the same or corresponding reference numerals, and redundant description is omitted. Also, the drawings are not intended to show the relative ratio between members or parts. Accordingly, specific dimensions can be determined by one skilled in the art in light of the following non-limiting embodiments.

(Configuration of thickness detector)
The configuration of the thickness detection apparatus 100 according to the embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the thickness detection device 100 according to the present embodiment includes a control unit 10 that controls the operation of the thickness detection device 100 and a rotating roller pair (a first roller 21 and a second roller described later). And conveying means 20 for conveying the recording medium sandwiched between the rollers 22). The thickness detection apparatus 100 also includes a detection unit 30 that detects the separation distance of the roller pair, a calculation unit 40 that calculates the thickness of the recording medium based on the detected separation distance, and a recording that is based on the calculated thickness. Determination means 50 for determining the conveyance state of the medium. Further, in this embodiment, the thickness detection apparatus 100 is a storage unit 60 that stores the operation state and operation conditions of the thickness detection apparatus 100, and an I / F that inputs and outputs information to and from the thickness detection apparatus 100 outside. And means 70.

  The thickness detection apparatus 100 according to the present embodiment transports (moves, carries in (carrys out), holds, etc.) the recording medium using the transport unit 20 (a roller pair or the like). Further, the thickness detection apparatus 100 detects the displacement amount of the separation distance of the roller pair of the transport unit 20 using the detection unit 30 and the calculation unit 40, and calculates the thickness of the recording medium based on the detected displacement amount. To do. Furthermore, the thickness detection apparatus 100 uses the determination unit 50 to determine whether or not the recording medium is being conveyed in a double feed state based on the calculated thickness of the recording medium. In the present embodiment, the double feed state refers to a transport state in which a plurality of recording media are transported in an overlapping manner.

  The control means 10 is a means for instructing each component of the thickness detection apparatus 100 to operate and controlling the operation of each component. The control means 10 controls the movement (conveyance etc.) of the recording medium by controlling the operation of the conveyance means 20. Further, the control unit 10 controls the operation of detecting and calculating the thickness of the recording medium by controlling the operation of the detection unit 30 and the calculation unit 40. Further, the control unit 10 controls the operation of determining the recording medium conveyance state by controlling the operation of the determination unit 50.

  Note that the control means 10 may be configured by a calculation processing device including a CPU (Central Processing Unit) of a known technique, a memory, and the like. Further, the control means 10 may control the operation of each component of the thickness detection apparatus 100 using, for example, a program (control program, application, etc.) stored in advance in the storage means 60 described later. Further, the control unit 10 may control the operation of each component of the thickness detection device 100 based on information input from the I / F unit 70 (such as an input unit).

  The conveying unit 20 is a unit that conveys (moves) the recording medium using a roller pair. The conveying means 20 includes a first roller 21 and a second roller 22 as a roller pair. Further, the conveying means 20 uses a first roller 21 and a second roller 22 having different diameters. Further, in the present embodiment, the conveying unit 20 uses the first roller 21 as a driven roller and the second roller 22 as a driving roller.

  Note that the conveyance means that can be used in the present invention may convey the recording medium by rotating either one or both of the first roller and the second roller constituting the roller pair. Here, the rotation shaft (22x) of the drive roller (second roller 22) is fixed at an arbitrary position of the thickness detection device 100. The rotation shaft (21x) of the driven roller (first roller 21) is supported so as to be movable in a direction (movable direction) perpendicular to the conveyance direction of the storage medium. That is, the driven roller is rotated following the rotation of the driving roller, and is displaced in the movable direction according to the thickness of the recording medium being conveyed.

  Specifically, the transport unit 20 according to the present embodiment has a recording medium Ms in the gap between the first roller 21 and the second roller 22 as shown in FIGS. 2A and 2B, for example. The first roller 21 and / or the second roller 22 are rotationally driven in the rotational direction Rb. Thereby, the conveyance means 20 can convey the recording medium Ms in the conveyance direction Ma. The first roller 21 and the second roller 22 may each include a plurality of roller members (for example, 21a to 21c and 22a to 22c in FIG. 5 described later).

  Further, as shown in FIG. 2B, for example, the transport unit 20 according to the present embodiment is perpendicular to the transport direction Ma of the recording medium Ms (FIG. 2A) when transporting the recording medium Ms. The first roller 21 is moved to Mb. Thereby, the thickness detection apparatus 100 can detect the displacement amount (or movement amount) of the first roller 21 when the recording medium Ms is transported using the detection unit 30 described later. The thickness detection device 100 uses the detection unit 30 to detect the displacement (or movement) of the second roller 22 when the first roller 21 is a driving roller and the second roller 22 is a driven roller. Amount) may be detected.

  The detecting unit 30 is a unit that detects the separation distance of the gap between the first roller 21 and the second roller 22 of the conveying unit 20. In the present embodiment, the detection means 30 detects the displacement amount of the first roller 21 (hereinafter referred to as “displacement amount Dm”), thereby separating the first roller 21 and the second roller 22 from each other. Is detected. For example, a lever-type encoder sensor, an optical (optical distance measuring) sensor, a magnetic (linear) sensor, an electrostatic sensor, or a direct-acting (small displacement) sensor can be used as the detecting means 30.

  Here, the lever-type encoder sensor is based on a rotation amount (or an encoder scale to be detected) of a rotation lever arranged on a roller or a roller shaft (hereinafter referred to as “roller etc.” in this paragraph). This is a sensor (detector) of a type that detects the amount of displacement of a roller or the like. An optical sensor is a sensor that irradiates light to a roller or the like, receives light reflected from the roller or the like, and detects the amount of displacement of the roller or the like based on the time required from irradiation (light emission) to light reception. . A magnetic linear sensor is a sensor that detects the amount of displacement of a roller or the like based on the position of the magnet (such as the amount of rotation of the lever) detected using a Hall IC or the like by arranging a lever that includes a magnet on a roller or the like. It is. An electrostatic sensor is a method in which a member whose capacitance varies in the positional relationship with the roller or the like is arranged in the movable direction of the roller or the like, and the amount of displacement of the roller or the like is detected based on the capacitance of the arranged member. Sensor. The direct-acting sensor is a sensor (detector) of a type that directly detects a moving amount (displacement amount) of a roller or the like with a load sensor or a strain cage.

  The detection means 30 according to the present embodiment is connected to a rotation shaft 21x of the first roller 21 as shown in FIG. The detecting unit 30 detects the displacement amount Dm of the separation distance between the first roller 21 and the second roller 22 by detecting the position (movement amount) of the rotation shaft 21 x of the first roller 21. Further, the displacement detection unit 31 does not sandwich the recording medium Ms in the gap between the first roller 21 and the second roller 22 (FIG. 2A), and sandwiches the recording medium Ms in the gap. The position (movement amount) of the rotation shaft 21x of the first roller 21 is detected (FIG. 2B).

  The detection means 30 may be connected to the rotation shaft 22x of the second roller 22. At this time, the detection unit 30 can detect the displacement amount Dm of the separation distance of the gap between the first roller 21 and the second roller 22 by detecting the position of the rotating shaft 22x.

  In addition, the detection unit 30 according to the present embodiment rotates the first roller 21 while rotating a plurality of positions (movement amounts) of the rotation shaft 21x corresponding to a plurality of rotation positions (a plurality of phases) of the first roller 21. ) Can be detected. For example, as shown in FIG. 3B, the detection means 30 rotates the first roller 21 (when the first roller 21 rotates at an arbitrary time (horizontal axis t in the figure) after the rotation of the first roller 21 starts. The position of the axis 21x) (vertical axis Dmc in the figure) is detected in time series. Thereby, the detection means 30 detects the several displacement amount Dm (fluctuation) of the separation distance of the 1st roller 21 and the 2nd roller 22 based on the detected several rotational position of the rotating shaft 21x. Can do.

  As shown in FIG. 3A, when the outer diameter of the first roller 21 and the outer diameter of the second roller 22 are different, the first roller 21 and the second roller 22 respectively. The displacement amounts Dm1 and Dm2 (movement amount) of fluctuate in the first period T1 or the second T2 corresponding to the respective diameters. In addition, the detection result detected by the detection unit 30 may include noise having a period Tn. Further, the displacement amount Dm (detected value) actually detected by the detection means 30 is obtained by combining the displacement amounts Dm1 and Dm2 of the first roller 21 and the second roller 22 and the noise displacement amount Dn of the period Tn. The displacement amount is Dmc (FIG. 3B).

  As shown in FIG. 3B, the detected value (for example, output voltage) actually detected by the detecting means 30 is a combined displacement amount Dmc that fluctuates in a specific period Tc. That is, when the outer diameters of the first roller 21 and the second roller 22 are different from each other and when the first roller 21 and the second roller 22 are decentered, and the detection result of the detection means 30 is periodic. When noise is included, the detection unit 30 detects the displacement amount Dmc of the period Tc. Here, in the present embodiment, the period Tc is the first period T1 of the first roller 21, the second period T2 of the second roller 22, and the period Tn of noise included in the detection result of the detection means 30. The period is the least common multiple period Pd.

  Further, the detection means 30 according to the present embodiment detects a plurality of displacement amounts Dm corresponding to a plurality of periods, using the least common multiple period Pd (the specific period Tc in FIG. 3B) as a detection period. . Here, the detection cycle is a cycle of an operation detected by the detection means 30. That is, the detection cycle is a cycle of the detection value detected by the detection unit 30.

  In this embodiment, the detection means 30 uses the detection cycle (the least common multiple cycle Pd) when the recording medium is not sandwiched in the gap between the first roller 21 and the second roller 22 (FIG. 2A). )) And a plurality of displacement amounts Dm (fluctuations in the displacement amount Dm) when sandwiched (FIG. 2B) are detected. For example, when the first roller 21 or the like is rotated a plurality of times, the detection unit 30 detects the displacement amount Dmc (FIG. 3B) that fluctuates in the least common multiple cycle Pd (detection cycle) in time series.

  Accordingly, the detection unit 30 according to the present embodiment uses the detection cycle (the least common multiple cycle Pd) when the recording medium Ms is not sandwiched in the gap between the first roller 21 and the second roller 22 and The position (movement amount) of the rotating shaft (21x or 22x) when sandwiched can be detected. That is, the detection means 30 according to the present embodiment can detect the periodic displacement amount Dm corresponding to the detection cycle even when the first roller 21 and the second roller 22 are eccentric. In addition, the detection means 30 has a periodicity corresponding to the detection period even when the diameters of the first roller 21 and the second roller 22 are different and the detection value includes periodic noise (error). The displacement amount Dm can be detected. Furthermore, since the detection means 30 (and the calculation means 40 described later) can detect the periodic displacement amount Dm corresponding to the detection cycle, the displacement amount Dm (difference thereof) that is not affected by noise is detected ( Calculation).

  The calculation means 40 is a means for calculating the thickness of the recording medium (hereinafter referred to as “thickness Tm”) based on the separation distance detected by the detection means 30. The calculation unit 40 includes a cycle calculation unit 41 that calculates the detection cycle of the detection unit 30 and a thickness calculation unit 42 that calculates the thickness Tm of the recording medium. In the present embodiment, the calculation unit 40 further includes a representative point extraction unit 43 that extracts a plurality of representative points from the displacement amount Dm detected by the detection unit 30.

  The period calculation unit 41 detects, as the detection period, the least common multiple of the first period T1 of the first roller 21, the second period T2 of the second roller 22, and the period Tn of noise included in the detection result of the detection unit 30. The period Pd is calculated. For example, the period calculation unit 41 may calculate the least common multiple period Pd using information stored in advance in the storage unit 60 (described later).

  The information stored in advance in the storage unit 60 can be information related to the detection cycle corresponding to the specifications of the transport unit 20, the detection unit 30, and other thickness detection devices 100. In addition, information stored in the storage unit 60 in advance can be information determined in advance through experiments or numerical calculations. Furthermore, the thickness detection apparatus 100 can input (store) information relating to a detection cycle predetermined in an experiment or the like to the storage unit 60 using the I / F unit 70 described later.

  The thickness calculation unit 42 calculates the thickness Tm based on the separation distance detected by the detection unit 30. In the present embodiment, the thickness calculator 42 calculates the thickness Tm based on a plurality of displacement amounts Dm detected by the detection means 30 (for example, the displacement amounts Dmc in FIG. 3B). Further, the thickness calculation unit 42 uses the plurality of displacement amounts Dm detected by the detection unit 30 when and when the recording medium is not sandwiched in the gap between the first roller 21 and the second roller 22. It is possible to calculate the average value of the plurality of displacement amounts Dm at the same time. Furthermore, the thickness calculator 42 may calculate the thickness Tm by comparing the calculated average values. For example, the thickness calculating unit 42 can set the difference between the calculated average values as the thickness Tm of the recording medium.

  The representative point extraction unit 43 extracts a plurality of representative points Dr from the displacement amount Dm detected by the detection unit 30. Here, in this embodiment, the representative point Dr is a thickness Tm among a plurality of feature points Df (for example, sampling points) obtained from the displacement amount Dm (Dmc) detected by the detection unit 30 in time series. It is a point (sampling point) extracted for use in calculation.

  Further, the representative point extraction unit 43 divides the amplitude of the displacement amount Dm detected by the detection unit 30 by a predetermined range Rt, selects a range in which the number of feature points Df extracted in the plurality of divided ranges is the largest, A plurality of feature points Df extracted in a selected range may be set as a plurality of representative points Dr.

  The calculation means 40 according to the present embodiment calculates a separation distance (thickness Tm of the recording medium) using the thickness calculation unit 42 based on the plurality of representative points Dr extracted using the representative point extraction unit 43. May be. For example, the calculating unit 40 (thickness calculating unit 42) may calculate an average value of a plurality of extracted representative points Dr, and use the calculated average value as the thickness Tm of the recording medium. Thereby, the calculation means 40 (thickness detection apparatus 100) can reduce the calculation amount which calculates the thickness Tm of a recording medium. That is, the calculation means 40 (thickness detection apparatus 100) can shorten the time for calculating the thickness Tm of the recording medium.

  The determination unit 50 is a unit that determines the conveyance state of the recording medium. In this embodiment, the determination unit 50 determines whether or not the recording medium is being conveyed in a double feed state based on the thickness Tm calculated by the calculation unit 40. The determination unit 50 also calculates the thickness of one recording medium calculated by the calculating unit 40 when the conveying unit 20 conveys one recording medium, and the other calculated by the calculating unit 40 when another recording medium is conveyed. The conveyance state may be determined by comparing the thickness of the recording medium. Further, the determination unit 50 may determine that the recording medium is being conveyed in a double feed state when, for example, the difference between the thickness of one recording medium and the thickness of another recording medium exceeds a predetermined threshold. . Note that the determination unit 40 uses the information input by the I / F unit 70 or the information stored in the storage unit 60 (for example, information on the thickness of the medium, information on other threshold values) to determine the conveyance state (multifeed). It may be determined whether or not it is in a state.

  Here, the predetermined threshold is a value corresponding to the type of the recording medium. Further, the predetermined threshold value can be set to a value corresponding to the specifications of the detection unit 30 and the other thickness detection apparatus 100. Furthermore, the predetermined threshold value can be set to a value determined in advance by experiment or numerical calculation.

  The storage unit 60 is a unit that stores information about the thickness detection apparatus 100 (for example, “information about operation”, “information about state”, or “information about processing”). The storage means 60 can use a known technique (hard disk, memory, ROM, RAM, DVD, etc.). In the present embodiment, the storage unit 60 can store in advance information related to the noise period Tn included in the detection result of the detection unit 30. The storage unit 60 also relates to the first period T1 of the first roller 21, the second period T2 of the second roller 22, and the least common multiple period Pd (for example, the specific period Tc in FIG. 3B). Information may also be stored.

  The I / F unit 70 is a unit that inputs and outputs information (for example, an electric signal) between the thickness detection device 100 and the outside of the thickness detection device 100. The I / F unit 70 can input information related to the operation of the thickness detection device 100 from an external device (such as a PC). Further, the I / F unit 70 can output information related to the operation of the thickness detection device 100 to an external device (such as a PC). The I / F unit 70 can include an input unit (for example, a user interface such as an operation panel) through which information (such as information on a recording medium) is input by the user from the outside of the thickness detection apparatus 100. Further, the I / F unit 70 can include an output unit (for example, a display unit such as a touch panel) that outputs (displays) information to the outside of the thickness detection apparatus 100.

(Function of thickness detector)
FIG. 4 is a functional block diagram illustrating an example of functions of the thickness detection apparatus 100 according to the embodiment of the present invention.

  As shown in FIG. 4, in the present embodiment, the thickness detection apparatus 100 (FIG. 1) is information (hereinafter, referred to as operation) of the thickness detection apparatus 100 acquired (input) using the I / F means 70. "Operation instruction") is output to the control means 10 (B01 in the figure). The thickness detection apparatus 100 according to the embodiment of the present invention corresponds to information regarding an image formation instruction (print request, print job) or the like when the thickness detection apparatus 100 is mounted on an image formation apparatus or the like. An “operation instruction” may be output.

  The control means 10 controls the operation of the thickness detection apparatus 100 based on the inputted “operation instruction” (B02). Specifically, the control unit 10 outputs a “conveyance instruction” to the conveyance unit 20 when the “operation instruction” is “an instruction regarding an operation for detecting the thickness of the recording medium”. Further, the control means 10 outputs a “calculation instruction” to the calculation means 40 when the “operation instruction” is “an instruction relating to an operation for detecting the thickness of the recording medium”. Further, the control means 10 outputs a “detection instruction” to the detection means 30 when the “operation instruction” is “an instruction relating to an operation for detecting the thickness of the recording medium”. Note that the control means 10 or the I / F means 70 (B01) may further output an “operation instruction” or the like to the storage means 60.

  Further, in the present embodiment, the control unit 10 outputs a “determination instruction (not shown)” to the determination unit 50 when the “operation instruction” is “an instruction regarding an operation for determining the conveyance state of the recording medium”. .

  The transport unit 20 transports the recording medium based on the input “transport instruction” (B03). Specifically, the transport unit 20 sandwiches the recording medium between the roller pair (the first roller 21 and the second roller 22) in accordance with the “transport instruction”, and the first roller 21 and / or The recording medium is conveyed by rotationally driving the second roller 22 (FIG. 2).

  Based on the input “calculation instruction”, the calculation means 40 uses the cycle calculation unit 41 and performs the cycle calculation step using the first cycle T 1 of the first roller 21 and the second cycle of the second roller 22. A period Pd (for example, a specific period Tc in FIG. 3B) of the least common multiple of the period T2 and the noise period Tn included in the detection result of the detection means 30 is calculated (B04). Further, the calculation unit 40 outputs information regarding the calculated least common multiple cycle Pd to the detection unit 30 as a detection cycle. Note that the calculation unit 40 may calculate the detection cycle (the least common multiple cycle Pd) by further using a program, a mathematical expression, or the like stored in the storage unit 60.

  The detection means 30 detects the separation distance between the first roller 21 and the second roller 22 based on the input “detection instruction” (B05). Specifically, the detection means 30 uses the least common multiple period Pd (detection period) as the reference value detection step, and does not sandwich the recording medium in the gap between the first roller 21 and the second roller 22. The gap separation distance (reference value) is detected. The detecting means 30 uses the least common multiple period Pd (detection period) as the displacement detection step, and the gap when the recording medium is sandwiched between the first roller 21 and the second roller 22. The separation distance (displacement amount) is detected.

  Next, the detection unit 30 outputs the detected detection result (hereinafter referred to as “detection data”) to the calculation unit 40 (and the storage unit 60). Specifically, the detection unit 30 detects, for example, the combined displacement amount Dmc shown in FIG. 3B, and obtains “detection data” regarding the detected displacement amount Dmc by the thickness calculation unit 42 of the calculation unit 40 and / or Alternatively, it can be output to the representative point extraction unit 43.

  As the thickness calculation step, the calculation means 40 calculates the thickness Tm of the recording medium using the thickness calculation unit 42 based on the input “detection data” (B06). Here, the thickness calculation unit 42 divides the detection results detected in the reference value detection step and the displacement amount detection step (B05) by the detection period (period Pd of the least common multiple), and uses the average value of the divided detection results. Thus, the thickness Tm of the recording medium may be calculated. The thickness calculator 42 can calculate, for example, the reference values of the plurality of separation distances detected in the reference value detection step and the average value of the displacement amounts of the plurality of separation distances detected in the displacement amount detection step. Further, the thickness calculation unit 42 can calculate the thickness Tm of the recording medium based on the calculated average value (for example, by comparing the calculated average value).

  Further, the thickness calculation unit 42 may calculate the thickness Tm of the recording medium using the representative point Dr extracted in the block B07 (described later).

  Furthermore, the thickness calculation unit 42 may further calculate the thickness Tm of the recording medium by further using a program, a mathematical expression, or the like stored in the storage unit 60.

  Next, the calculation unit 40 outputs the calculated calculation result (hereinafter referred to as “calculation data”) to the determination unit 50, the storage unit 60 and / or the control unit 10.

  On the other hand, in the present embodiment, the calculation unit 40 uses the representative point extraction unit 43 to calculate a plurality of representative points from the displacement amount Dm detected by the detection unit 30 based on the input “detection data” in the block B07. It can be extracted into Dr. For example, the representative point extraction unit 43 divides the amplitude of the detected displacement amount Dm (B05) by a predetermined range (division range), selects a range having the largest number of feature points extracted in the plurality of divided ranges, A plurality of representative points Dr can be extracted in the selected range. Next, the calculation unit 40 can output the extracted representative points Dr to the thickness calculation unit 42 (and the storage unit 60).

  Note that the calculation means 40 that can be used in the present invention need not extract a plurality of representative points Dr. Further, the calculation means 40 that can be used in the present invention may not include the representative point extraction unit 43. In other words, the calculating means 40 that can be used in the present invention may calculate the thickness Tm of the recording medium by averaging the detected fluctuation values of the displacement amount (block B06 described above).

  The determination unit 50 determines the conveyance state of the recording medium based on the inputted “calculation data” (B08). The determination unit 50 outputs the determined determination result (hereinafter referred to as “determination data”) to the storage unit 60 and / or the control unit 10. Note that the determination unit 50 may further determine the conveyance state by further using medium information stored in the storage unit 60.

  The storage unit 60 stores information related to the operation of the transport unit 20, “detection data” of the detection unit 30, “calculation data” of the calculation unit 40, “determination data” of the determination unit 50, and the like (B09). In addition, the storage unit 60 can output the stored information using the I / F unit 70.

(Thickness detection method program and recording medium on which the program is recorded)
According to the program Pr of the thickness detection method according to the embodiment of the present invention, the least common multiple of the first cycle of the first roller, the second cycle of the second roller, and the cycle of noise included in the detection result A period calculating step for calculating a period, and a distance of the gap when the recording medium is not sandwiched between the first roller and the second roller, using the calculated least common multiple period as a detection period. A reference value detecting step for detecting, a displacement amount detecting step for detecting the separation distance when the recording medium is sandwiched in the gap, and a detection result detected in the reference value detecting step and the displacement amount detecting step. And a thickness calculating step of calculating a thickness of the recording medium using an average value of the divided detection results. . According to this configuration, an effect equivalent to that of the thickness detection apparatus 100 according to the embodiment of the present invention can be obtained.

  Further, the present invention may be a recording medium Md that can be read by a computer in which the program Pr is recorded. The recording medium Md on which the program Pr is recorded includes a flexible disk (FD), a CD-ROM (Compact Disk-ROM), a CD-R (CD Recordable), a DVD (Digital Versatile Disk), and other computer-readable media, and A semiconductor memory such as a flash memory, a RAM, and a ROM, a memory card, an HDD (Hard Disc Drive), and other computer-readable devices can be used.

  As described above, according to the thickness detection apparatus 100 according to the present embodiment, the first period T1 of the first roller 21, the second period T2 of the second roller 22, and the period Tn of noise included in the detection result. A period Pd (a specific period Tc) of the least common multiple of can be calculated. Further, according to the detection device 100, the separation distance (displacement amount Dm) of the roller pair can be detected by using the calculated least common multiple period Pd as the detection period. Furthermore, the detection apparatus 100 can calculate the thickness Tm of the recording medium based on the detected separation distance.

  Further, according to the thickness detection apparatus 100 according to the present embodiment, the recording medium is sandwiched between the first roller 21 and the second roller 22 by using the calculated least common multiple period Pd as the detection period. It is possible to detect the displacement amount Dm of the separation distance when it is not and when it is sandwiched. That is, the thickness detection apparatus 100 can detect the periodic displacement amount Dm corresponding to the detection period (Pd) even when the detection result of the detection unit 30 includes periodic noise. It is possible to detect (calculate) the displacement Dm that is not affected by noise.

  Furthermore, according to the thickness detection apparatus 100 according to the present embodiment, even when the first roller 21 and the second roller 22 are decentered, the periodic displacement amount corresponding to the detection cycle (the least common multiple cycle Pd). Dm can be detected. Further, according to the thickness detection device 100, even when the diameters of the first roller 21 and the second roller 22 are different, the periodic displacement amount Dm corresponding to the detection cycle (the least common multiple cycle Pd) is detected. can do. That is, according to the thickness detection apparatus 100, the difference between the displacement amount Dm that is not affected by the periodic noise and the eccentricity of the roller pair can be calculated based on the detected periodic displacement amount Dm. The thickness Tm that is not affected by the eccentricity of the roller pair can be calculated.

  The present invention will be described using an embodiment of a thickness detection device and an image forming apparatus including the thickness detection device.

Example 1
The present invention will be described using the thickness detection device 110 according to the first embodiment of the present invention.

(Configuration of thickness detection device) and (Function of thickness detection device)
The configuration and the like of the thickness detection device 110 according to the present embodiment are shown in FIGS. Note that the configuration and the like of the thickness detection device 110 according to the present embodiment are basically the same as the configuration and the like of the thickness detection device 100 according to the embodiment, and thus different parts will be mainly described.

  The detection means 30 according to the present embodiment includes a displacement detection unit 31 that detects a displacement amount Dm of the separation distance of the roll pair, and rotational positions of the first roller 21 and the second roller 22 (hereinafter referred to as “rotational position Dr”). And a rotational position detection unit 32 that detects. In this embodiment, the detection means 30 detects the distance between the first roller 21 and the second roller 22 by detecting the displacement amount Dm of the first roller 21 using the displacement detector 31. . Further, the detecting means 30 detects the rotational position Dr of the first roller 21 and the second roller 22 using the rotational position detector 32, so that the phase between the first roller 21 and the second roller 22 is detected. Identify relationships. Furthermore, the detection means 30 determines the timing at which the displacement detector 31 detects the displacement amount Dm based on the rotational position Dr detected by the rotational position detector 32.

  The displacement detector 31 according to the present embodiment detects a displacement amount Dm of the separation distance between the first roller 21 and the second roller 22. As shown in FIG. 5, the displacement detector 31 is connected to the rotation shaft 21 x of the first roller 21. The displacement detector 31 detects the displacement amount Dm of the separation distance between the first roller 21 and the second roller 22 by detecting the position (movement amount) of the rotation shaft 21 x of the first roller 21. Further, the displacement detection unit 31 sandwiches the recording medium Ms between the first roller 21 and the second roller 22 when the recording medium Ms is not sandwiched (for example, FIG. 2A). The position of the rotating shaft 21x of the first roller 21 is detected when it is moving (for example, FIG. 2B).

  Further, the displacement detection unit 31 can detect the displacement amount Dm at a desired timing (for example, t0, t1, or t2 in FIG. 3) based on the rotation position Dr detected by the rotation position detection unit 32. Thereby, the displacement detection part 31 can detect the displacement amount Dm corresponding to a detection period (period Pd of the least common multiple).

  The displacement detector 31 according to the present embodiment may be connected to the rotation shaft 22x of the second roller 22. At this time, the displacement detector 31 can detect the displacement amount Dm of the separation distance of the gap between the first roller 21 and the second roller 22 by detecting the position of the rotating shaft 22x.

  The rotational position detector 32 according to this embodiment detects the rotational position Dr of the first roller 21 and the second roller 22. As the rotational position detector 32, for example, a photo sensor, a rotary encoder, a rotational phase detector with a built-in motor, or the like can be used.

  The rotational position detector 32 uses a photo sensor in this embodiment. Here, as shown in FIGS. 5 and 6, the rotational position detector 32 is a rotating disk 32p (first shaft) fixed to the rotational shaft 21x of the first roller 21 and the rotational shaft 22x of the second roller 22, respectively. The positions of the rotating disk 32pa and the second rotating disk 32pb) are detected. Thereby, the rotation position detection unit 32 can detect the rotation positions Dr of the first roller 21 and the second roller 22. The rotational position detector 32 (detecting means 30) that can be used in the present invention may be a circular or elliptical or other shape of rotating disk.

  Here, the photosensor detects the position or presence of an object by detecting light. For example, as shown in FIG. 6A, the photosensor 32s can detect (detect) the rotating disk 32p when the rotating disk 32p blocks light. Further, for example, as shown in FIG. 6B, the photo sensor 32s can detect that the rotating disk 32p has moved when the rotating disk 32p does not block light. The rotational position detector 32 may use a known technique for a rotary encoder or a rotational phase detector with a built-in motor.

  The representative point extraction unit 43 of the calculation unit 40 according to the present embodiment divides the amplitude of the displacement amount Dm detected by the detection unit 30 into a predetermined range Rt, and the number of feature points Df extracted respectively in the plurality of divided ranges. Select the range with the largest. In addition, in this embodiment, the representative point extraction unit 43 may further specify a correction range Rr for enlarging the selected range. Next, the representative point extraction unit 43 sets a plurality of feature points Df extracted in the selected range as a plurality of representative points Dr. The representative point extraction unit 43 may use a plurality of feature points Df extracted in the correction range Rr as a plurality of corrected representative points Dra.

  Specifically, as shown in FIG. 7, the representative point extraction unit 43 divides the amplitude RD of the displacement amount Dm detected by the detection unit 30 into a predetermined range, and is extracted in a plurality of divided ranges. A range Rm having the largest number (for example, sampling points) is selected. The representative point extraction unit 43 may further specify a correction range Rr to be added to the selected range Rm. Next, the representative point extraction unit 43 sets a plurality of feature points Df extracted in the selected range Rm as a plurality of representative points Dr. Further, the representative point extraction unit 43 may use a plurality of feature points Df further extracted in the correction range Rr as a plurality of corrected representative points Dra.

  The operation result (extracted or selected information) of the representative point extracting unit 43 may be stored in a memory unit (not shown) or a storage unit 60 built in the representative point extracting unit 43. Thereby, the thickness detection apparatus 110 can perform calculation or the like using the calculation unit 40 or the like by appropriately using the operation result of the representative point extraction unit 43 stored in the memory unit or the like.

  The thickness calculating unit 42 of the calculating unit 40 according to the present embodiment calculates the average value of the plurality of representative points Dr extracted by the representative point extracting unit 43, and sets the calculated average value as the thickness Tm of the recording medium. Note that the thickness calculation unit 42 may further calculate an average value by using the plurality of corrected representative points Dra extracted by the representative point extraction unit 43, and use the calculated average value as the thickness Tm of the recording medium.

  As described above, according to the thickness detection device 110 according to the present embodiment, the rotational position Dr of the first roller 21 and the like can be detected using the rotational position detection unit 32, and therefore based on the detected rotational position Dr. Thus, the timing at which the displacement detector 31 detects the displacement amount Dm can be determined. Further, according to the thickness detection device 110, the representative point extraction unit 43 is used to divide the amplitude RD of the displacement amount Dm detected by the detection means 30 into the predetermined range Rt, and extract the respective divided ranges. A range Rm having the largest number of feature points Df can be selected. Further, according to the thickness detection device 110, the representative point extraction unit 43 is used to set the average value of the plurality of feature points Df (representative points Dr) extracted in the selected range Rm as the thickness Tm of the recording medium. be able to.

  Further, according to the thickness detection apparatus 110 according to the present embodiment, the representative point extraction unit 43 is used to further specify the correction range Rr to be expanded to the selected range Rm, and to extract a plurality of features extracted in the correction range Rr. The point Df can be a plurality of corrected representative points Dra. Further, according to the thickness detection device 110, the thickness calculation unit 42 is used to calculate and calculate an average value of the plurality of representative points Dr (and the plurality of corrected representative points Dra) extracted by the representative point extraction unit 43. The average value obtained can be used as the thickness Tm of the recording medium. Furthermore, according to the thickness detection apparatus 110, the average value of the plurality of representative points Dr (and the plurality of corrected representative points Dra) can be set as the thickness Tm of the recording medium using the thickness calculation unit 42. The accuracy of the calculated thickness Tm can be improved. That is, since the thickness detection device 110 can calculate the thickness Tm of the recording medium based on a plurality of representative points Dr and the like, noise having no periodicity (or unexpected noise) is included in the detection result. Even in this case, it is possible to calculate the thickness Tm from which the influence of the noise is removed.

  Furthermore, according to the thickness detection apparatus 110 according to the present example, the same effect as that of the thickness detection apparatus 100 according to the embodiment can be obtained.

(Example 2)
The present invention will be described using an image forming apparatus 200 according to Embodiment 2 of the present invention. Here, the image forming apparatus is an apparatus (such as an apparatus, a device, or a unit) that forms an image on the surface of a recording medium in this embodiment.

(Configuration of image projection device)
The configuration of the image forming apparatus 200 according to the present embodiment will be described with reference to FIG. Note that the configuration of the image forming apparatus 200 according to the present embodiment includes the configuration of the thickness detection apparatus 100 according to the embodiment, and thus different parts will be mainly described.

  As shown in FIG. 8, an image forming apparatus 200 according to this embodiment includes an image forming unit 80 that forms an image on a recording medium, a paper feeding unit 81 that feeds (loads in) the recording medium, and the like. An image reading unit 82 that reads a (formed) image (image data), a document conveying unit 83 that conveys a document, and the like are included. Here, in this embodiment, the image forming apparatus 200 includes the thickness detection device 100 according to the embodiment (or the thickness detection device 110 according to the first embodiment) in the paper feeding unit 81. For example, the image forming apparatus 200 can include a thickness detection device (100 or the like) on the conveyance roller 247 of the paper supply unit 81.

  The image forming unit 80 is a unit that forms an image on the surface of the recording medium. The image forming unit 80 includes an intermediate transfer belt 210 that is an endless belt, and an image forming unit 220 that generates a toner image to be transferred onto the surface of the intermediate transfer belt 210. Further, the image forming unit 80 includes a secondary transfer unit 222 that transfers the toner image on the surface of the intermediate transfer belt 210 to the surface of the recording medium, a fixing unit 225 that fixes (fixes) the transfer image (toner image) on the surface of the recording medium, and the like. Is provided.

  As the intermediate transfer belt 210, for example, a multilayer belt can be used. The intermediate transfer belt 210 is a multi-layer belt in which an elastic layer (such as a coat layer with good smoothness) is laminated on a base layer that is disposed on a material (such as canvas) that is not easily stretched with a fluororesin having a small elongation or a rubber material having a large elongation. Also good. Here, as the elastic layer, for example, a coating layer in which a fluorine resin is coated on the surface of fluorine-based rubber or acrylonitrile-butadiene copolymer rubber can be used.

  In this embodiment, the intermediate transfer belt 210 is supported by being supported by three support rollers 214 to 216. Further, the intermediate transfer belt 210 is rotated (rotated) in the clockwise direction by rotating the support roller 214 and the like in the clockwise direction.

  In this embodiment, the image forming unit 220 includes a photoreceptor unit (such as a photoreceptor drum) 240 that generates a toner image (electrostatic latent image) corresponding to an image to be formed, and a charging unit 218 that charges the photoreceptor unit 240. And a developing unit 221 for developing the toner image on the photoconductor unit 240. The image forming unit 220 includes a cleaning unit that cleans the photosensitive unit 240.

  In this embodiment, the image forming unit 220 includes a photoreceptor unit 240 corresponding to each color (for example, black (K), yellow (Y), magenta (M), and cyan (C)). The photosensitive unit 240 and the like are disposed at a position facing the intermediate transfer belt 210 along the moving direction of the intermediate transfer belt 210 between the first support roller 214 and the second support roller 215. For example, the image forming unit 220 may include an IC tag or a unit that can be attached to and detached from the image forming apparatus 200.

  The developing unit 221 irradiates each color photoconductor unit 240 (surface of the photoconductor drum) with laser light. As a result, the developing unit 221 can generate an electrostatic latent image corresponding to the image of each color on the photoconductor unit 240 (surface of the photoconductor drum) of each color.

  The secondary transfer unit 222 transfers the toner image (color image) on the intermediate transfer belt 210 onto a recording medium. The secondary transfer unit 222 includes a secondary transfer belt 224 to which a toner image on the intermediate transfer belt 210 is transferred, a cleaning unit 217 for removing residual toner remaining on the intermediate transfer belt 210 after image formation, and the like.

  The toner image on the intermediate transfer belt 210 is transferred to the secondary transfer belt 224. The secondary transfer belt 224 transfers the transferred toner image onto a recording medium. As the secondary transfer belt 224, an endless belt is used in this embodiment. Further, the secondary transfer belt 224 is stretched around two rollers 223. Further, the secondary transfer belt 224 is disposed so as to contact a part of the intermediate transfer belt 210 pushed up by the third support roller 216.

  The cleaning unit 217 removes residual toner remaining on the intermediate transfer belt 210 after the toner image is transferred. In this embodiment, the cleaning unit 217 is disposed on the downstream side with respect to the turning direction of the third support roller 216.

  The fixing unit 225 fixes (fixes) the transfer image (toner image) on the recording medium. In this embodiment, the fixing unit 225 is disposed on the downstream side of the secondary transfer belt 224 (downstream side with respect to the recording medium conveyance direction). Here, the fixing unit 225 includes an endless fixing belt 226 and a movable pressure roller 227. The fixing unit 225 heats the recording medium using the fixing belt 226 and pressurizes the recording medium using the pressure roller 227. As a result, the fixing unit 225 can fix the toner image on the recording medium after melting the toner image.

  The paper feeding means 81 is a means for feeding (loading in) a recording medium on which an image is formed. The paper feed unit 81 includes a paper feed tray 244 that stores a recording medium before image formation, a paper feed roller 245 that carries a recording medium stored in the paper feed tray 244, a paper feed path 246, a transport roller 247, and a registration roller. 249 and the like. The paper feeding means 81 includes a manual feed tray 251 (and a separation roller 250 and the like) on which the user manually places the recording medium, and a reversing unit 228 that inverts the recording medium to form images on both sides of the recording medium. Also have. The sheet feeding means 81 is a conveyance sensor (thickness detection according to the embodiment) that detects whether or not the recording medium is suitably conveyed or whether or not a conveyance jam (paper jam) has occurred. The apparatus 100 or the like may be further arranged in the paper feed path 246 or the like.

  The paper feed tray 244 may be equipped with a medium sensor (for example, a photo sensor). As a result, the image forming apparatus 200 uses the medium sensor to check whether the recording medium stored in the paper feed tray 244 is present, the remaining amount, the size, the orientation, and each tray is correctly mounted on the image forming apparatus 200. It can be detected whether or not.

  The registration roller 249 may be grounded. Further, the image forming apparatus 200 may apply a bias voltage to the recording medium using a registration roller 249 in order to remove paper dust and the like of the recording medium.

  As the registration roller 249, for example, a conductive rubber roller can be used. Further, the registration roller 249 may have a cylindrical shape having a diameter of 18 mm, for example, and the surface thereof may be covered with a conductive NBR rubber having a thickness of 1 mm. Here, the electrical resistance of the registration roller 249 is about 109 Ωcm, which is the volume resistance of the rubber material in the above configuration.

  Further, the surface of the recording medium after passing through the registration roller 249 to which a bias is applied is slightly negatively charged. For this reason, the image forming apparatus 200 may apply a voltage to the toner image transfer side (front side) of the intermediate transfer belt 210 in accordance with the bias voltage applied to the registration roller 249. Further, when a bias voltage is applied to the registration roller 249, the image forming apparatus 200 may apply a voltage to the transfer roller 262 that contacts the back surface of the recording medium. The image forming apparatus 200 may apply a voltage of about −800V to the intermediate transfer belt 210 and a voltage of about + 200V to the transfer roller 262, for example.

  In order to form an image on the back surface of the recording medium, the reversing unit 228 reverses and outputs the recording medium having the image formed on the front surface. The reversing unit 228 can be disposed, for example, below the two transfer unit 222 and the fixing unit 225.

  The image reading unit 82 is a unit that reads (acquires) an image (image data) described on a document. The image reading unit 82 reads a document placed on the contact glass 232.

  Specifically, in this embodiment, the image reading unit 82 uses the first carriage 233 and the second carriage 234 to scan the surface of the document on which the image is formed. At this time, the image reading unit 82 irradiates light (scanning light) in the direction of the contact glass 232 using a light source mounted on the first carriage 233. Further, the image reading unit 82 reflects the reflected light reflected on the surface of the document by the first mirror mounted on the first carriage 233. Next, the image reading unit 82 further reflects the reflected light reflected by the first mirror by the mirror mounted on the second carriage 234. Further, the image reading unit 82 transmits the reflected light reflected by the mirror mounted on the second carriage 234 to the imaging lens 235 and forms an image on the reading sensor 236 (for example, CCD, image sensor).

  Accordingly, the image reading unit 82 (image forming apparatus 200) can acquire image data (image signal, pixel output signal) corresponding to the image formed using the reading sensor 236. The image reading unit 82 generates image data of each color corresponding to each color (for example, black (K), yellow (Y), magenta (M), and cyan (C)) based on the acquired image data. Can do.

  The document conveying unit 83 is a unit that conveys the document placed on the document feeding table 230 onto the contact glass 232. In this embodiment, the document conveying means 83 uses an automatic document feeder (ADF).

(Operation to form an image)
An operation in which the image forming apparatus 200 according to the second embodiment of the present invention forms an image on a recording medium will be described with reference to FIG.

  First, when the start switch of the operation unit (I / F unit 70 in FIG. 1) is pressed, the image forming apparatus 200 according to the present embodiment is placed on the document feeding table 230 using the document transport unit 83. The original is conveyed onto the contact glass 232. Next, the image forming apparatus 200 uses the image reading unit 82 to read the image described on the document conveyed on the contact glass 232. At this time, based on the image data acquired by the reading sensor 236, the image forming apparatus 200 has images of each color corresponding to each color (for example, black (K), yellow (Y), magenta (M), and cyan (C)). Get the data.

  In addition, the image forming apparatus 200 starts turning (rotating drive) of the intermediate transfer belt 210. Further, the image forming apparatus 200 starts preparation for image formation of the image forming unit 220.

  Furthermore, the image forming apparatus 200 starts an image forming sequence for each color, and the exposure laser modulated based on the image data corresponding to each color using the developing unit 221 on each color photosensitive drum (photosensitive unit 240). Irradiate (irradiation light). Next, the image forming apparatus 200 superimposes and transfers toner images corresponding to the respective colors on the intermediate transfer belt 210. Accordingly, the image forming apparatus 200 can form a full-color toner image on the intermediate transfer belt 210.

  On the other hand, the image forming apparatus 200 uses the paper supply unit 81 to convey a recording medium on which an image is to be formed. Specifically, the paper feed unit 81 (image forming apparatus 200) rotates one of the paper feed rollers 242, and takes out the recording medium from one of the paper feed trays 244 held in multiple stages by the paper feed unit 243. . Further, the paper feeding unit 81 separates only one recording medium using the separation roller 245, loads the separated recording medium using the conveyance roller 247, and abuts the loaded recording medium against the registration roller 249. , Stop.

  Note that the image forming apparatus 200 may transport (feed) the recording medium inserted into the manual feed tray 251 in the same manner as the recording medium stored in the paper feeding tray 244 described above. Specifically, the paper feed unit 81 (image forming apparatus 200) separates one of the recording media on the manual tray 251 by rotating the separation roller 250 when the user inserts the recording media into the manual feed tray 251. To do. Next, the paper feeding unit 81 pulls the separated recording medium into the manual paper feeding path 253, abuts against the registration roller 249 and stops.

  Here, the image forming apparatus 200 according to the present embodiment can include the thickness detection apparatus 100 according to the embodiment on the conveyance roller 247 of the paper feeding unit 81. Therefore, the image forming apparatus 200 according to the present embodiment can detect the thickness Tm of the recording medium when the recording medium is sandwiched between the two rollers (roller pairs) of the conveying roller 247. Further, since the image forming apparatus 200 can detect the thickness Tm of the recording medium using the conveyance roller 247 (thickness detection apparatus 100), the conveyance state of the recording medium is determined based on the detected thickness Tm. Judgment can be made. The image forming apparatus 200 can determine, for example, whether the conveyance state is a double feed state or whether a conveyance jam (paper jam) has occurred.

  Thereafter, the image forming apparatus 200 transfers the recording medium stopped on the registration roller 249 to the secondary transfer unit 222 in response to the timing when the leading edge of the toner image on the intermediate transfer belt 210 enters the secondary transfer unit 222. Carry in. Next, the image forming apparatus 200 uses the image forming unit 80 to transfer the toner image on the intermediate transfer belt 210 to the surface of the recording medium. Thereafter, the image forming apparatus 200 carries out the recording medium on which the toner image is transferred to the fixing unit 225. Next, the image forming apparatus 200 uses the fixing unit 225 to melt and fix (fix processing) the toner image on the recording medium.

  After that, the image forming apparatus 200 uses the switching claw 255 to guide the recording medium fixed by the fixing unit 225 to the discharge roller 256 and discharge it to the discharge tray 257. Note that the image forming apparatus 200 may guide the recording medium to the reversing unit 228 using the switching claw 255 and then discharge the recording medium to the paper discharge tray 257 after forming an image on the back surface of the recording medium. .

  As described above, according to the image forming apparatus 200 according to the second exemplary embodiment of the present invention, the recording roller 247 is rotated while the recording medium is sandwiched between the two rollers (roller pair) of the conveyance roller 247, thereby recording. Media can be transported. Further, according to the image forming apparatus 200, since the recording medium can be conveyed while being sandwiched between the two rollers of the conveying roller 247, the thickness Tm of the recording medium can be detected when the recording medium is conveyed. it can. Furthermore, according to the image forming apparatus 200, the thickness Tm of the recording medium being conveyed can be detected, so the conveyance state of the recording medium can be determined based on the detected thickness Tm.

  Moreover, according to the image projection apparatus 200 which concerns on Example 2 of this invention, the effect similar to the thickness detection apparatus 100 which concerns on embodiment can be acquired.

  The preferred embodiments and examples of the thickness detection apparatus and the image forming apparatus according to the present invention have been described above, but the present invention is not limited to the above-described embodiments and examples. The present invention can be variously modified or changed in light of the appended claims.

DESCRIPTION OF SYMBOLS 100,110: Thickness detection apparatus 200: Image forming apparatus 20: Conveyance means 21: 1st roller 22: 2nd roller 30: Detection means 40: Calculation means 41: Period calculation part 42: Thickness calculation part 43: Representative point extraction unit 50: determination unit 80: image forming unit Pr: program Md: recording medium on which program Pr is recorded Pd: detection cycle (cycle of least common multiple)
T1: first period (period of displacement of the first roller)
T2: Second cycle (cycle of displacement of the second roller)
Tn: Noise period (period of noise included in the detection result)
Dm: Displacement amount Tm: Recording medium thickness Df: Feature point Dr: Representative point Dra: Corrected representative point Rt: Division range (predetermined range)
Rr: Correction range

JP 2009-227404 A

Claims (7)

Conveying means for conveying the recording medium sandwiched between the first roller and the second roller by rotationally driving the first roller and / or the second roller;
Detecting means for detecting a separation distance of the gap;
A period calculation unit that calculates a first period of the first roller, a second period of the second roller, and a least common multiple of a period of noise included in the detection result of the detection unit; and the recording medium A calculation means comprising a thickness calculation unit for calculating the thickness of
The detection means detects a plurality of displacement amounts of the separation distance when the recording medium is not sandwiched and when the recording medium is sandwiched, with the least common multiple period calculated by the period calculation unit as a detection period. ,
The calculating means further includes a representative point and a corrected representative point extracting unit for extracting a plurality of representative points and a plurality of corrected representative points from a plurality of displacement amounts respectively detected by the detecting means.
The representative point and the corrected representative point extracting unit divides the amplitudes of the plurality of displacement amounts detected by the detecting unit in a predetermined range, and selects a range having the largest number of feature points extracted in the divided plurality of ranges. Selecting, extracting the plurality of representative points in the selected range, designating a correction range for enlarging the selected range, extracting the plurality of corrected representative points in the designated correction range,
The thickness calculation unit calculates an average value of a plurality of representative points and a plurality of corrected representative points extracted by the representative point and the corrected representative point extraction unit, and uses the calculated average value as a thickness of the recording medium. A thickness detection apparatus characterized by the above.   The thickness detection apparatus according to claim 1, wherein the detection means uses a lever type encoder sensor, an optical sensor, a magnetic sensor, an electrostatic sensor, or a direct acting sensor. Based on the thickness calculated by the calculating means, further comprising determining means for determining whether or not the recording medium is conveyed in a double-feed state;
The determining means calculates the thickness of the one recording medium calculated by the calculating means when the conveying means conveys one recording medium and the calculating means when the conveying means conveys another recording medium. The thickness detection apparatus according to claim 1, wherein it is determined whether or not the sheet is conveyed in the double-feed state by comparing with a thickness of the other recording medium.   An image forming apparatus comprising the thickness detection device according to claim 1. A method of detecting the thickness of a recording medium conveyed by being driven by rotating a first roller and / or a second roller, sandwiched between a gap between the first roller and the second roller. ,
A detection step of detecting a separation distance of the gap;
A cycle calculating step for calculating a cycle of a least common multiple of a first cycle of the first roller, a second cycle of the second roller, and a noise cycle included in the detection result of the detection step;
A reference value detection step of detecting a plurality of displacement amounts of the separation distance when the recording medium is not sandwiched in the gap, with the least common multiple period calculated in the period calculation step as a detection period;
A displacement amount detecting step for detecting a plurality of displacement amounts of the separation distance when the recording medium is sandwiched in the gap;
Dividing the amplitudes of a plurality of displacement amounts detected in the reference value detection step and the displacement amount detection step in a predetermined range, and selecting a range having the largest number of feature points extracted in the plurality of divided ranges; a representative point extraction step of extracting the representative points of the multiple Te range odor that the selected,
Specify the correction range to expand the range of said selected, the correction representative point extracting step of extracting the correction representative points of multiple Te correction range odor that the specified,
Calculating a mean value of a plurality of representative points and a plurality of corrected representative points extracted in the representative point extracting step and the corrected representative point extracting step, and a thickness calculating step using the calculated average value as the thickness of the recording medium; A thickness detection method comprising:   A program for causing a computer to execute the thickness detection method according to claim 5.   A computer-readable recording medium on which the program according to claim 6 is recorded.

Images