JP2012056729A - Paper conveying apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper conveying apparatus capable of carrying out detection in an environment suitable for detection by an ultrasonic method, and an image forming apparatus.SOLUTION: The paper conveying apparatus includes: a transmitting sensor 112 transmitting ultrasonic waves after paper jammed in a paper conveying path 108 is removed or the paper conveying apparatus 100 is started; a receiving sensor 114 located facing the transmitting sensor 112 with the conveying path 108 held in between to receive the ultrasonic waves transmitted from the transmitting sensor 112; and a paper presence determining part 138 determining the presence of remaining paper in the conveying path 108 based on the ultrasonic waves received by the receiving sensor 114.

Description

  The present invention relates to a sheet conveying device and an image forming apparatus.

  2. Description of the Related Art Conventionally, there has been known an ultrasonic detection technique that uses an ultrasonic transmitter and receiver to detect a sheet in a conveyance path such as a double feed of a sheet conveyed in the conveyance path. For example, Patent Literature 1 discloses a technique for detecting double feeding of paper by changing a threshold value according to the thickness of the paper conveyed on the conveyance path and comparing the changed threshold value with attenuated ultrasonic waves. ing. According to the technique disclosed in Patent Document 1, since the threshold value is changed according to the fluctuation of the attenuation amount of the ultrasonic wave, erroneous detection of double feeding can be reduced.

  However, even in the prior art disclosed in Patent Document 1, false detection cannot be reduced unless detection is performed in an environment suitable for ultrasonic detection.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a sheet conveying device and an image forming apparatus capable of performing detection in an environment suitable for ultrasonic detection.

  In order to solve the above-described problems and achieve the object, a paper transport device according to one aspect of the present invention is a paper transport device, and after the paper jammed in a transport path for transporting paper is removed or the above-mentioned A transmission sensor that transmits ultrasonic waves after the paper transport device is activated, a reception sensor that is positioned opposite to the transmission sensor across the transport path, and that receives the ultrasonic waves transmitted from the transmission sensor; Paper presence / absence determining means for determining presence / absence of remaining paper in the conveyance path based on the ultrasonic wave received by the reception sensor.

  An image forming apparatus according to another aspect of the present invention includes the above-described sheet conveying device.

  According to the present invention, it is possible to perform detection in an environment suitable for ultrasonic detection.

FIG. 1 is a side view schematically showing an example of the mechanical configuration of the sheet conveying apparatus of the present embodiment. FIG. 2 is a schematic diagram illustrating an example of a transmission sensor and a reception sensor according to the present embodiment. FIG. 3 is a block diagram showing an example of the electrical configuration of the sheet conveying apparatus of the present embodiment. FIG. 4 is a diagram illustrating an example of ultrasonic waves amplified by the double feed determination amplification unit of the present embodiment. FIG. 5 is a diagram illustrating an example of ultrasonic waves amplified by the paper presence / absence determination amplification unit of the present embodiment. FIG. 6 is a diagram illustrating an example of ultrasonic waves amplified by the abnormality determination amplification unit of the present embodiment. FIG. 7 is a diagram illustrating an example of ultrasonic waves integrated by the double feed determination unit of the present embodiment. FIG. 8 is a diagram illustrating an example of an ultrasonic wave integrated by the double feed determination unit of the present embodiment. FIG. 9 is a diagram illustrating an example of ultrasonic waves integrated by the paper presence / absence determination unit of the present embodiment. FIG. 10 is a diagram illustrating an example of ultrasonic waves integrated by the sheet presence / absence determination unit of the present embodiment. FIG. 11 is a diagram illustrating an example of ultrasonic waves integrated by the abnormality determination unit of the present embodiment. FIG. 12 is a diagram illustrating an example of ultrasonic waves integrated by the abnormality determination unit of the present embodiment. FIG. 13 is a flowchart illustrating an example of double feed detection processing according to the present embodiment. FIG. 14 is a flowchart illustrating an exemplary sheet presence / absence detection process according to the present embodiment. FIG. 15 is a flowchart illustrating an example of abnormality detection processing according to the present embodiment. FIG. 16 is a flowchart illustrating an example of an initial check process performed by the paper conveyance device of the present embodiment. FIG. 17 is a block diagram illustrating a hardware configuration example of an image forming apparatus to which the sheet conveying device of the present embodiment is applied.

  Hereinafter, embodiments of a sheet conveying device and an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings. A sheet conveying apparatus described in the following embodiments is applied to an image forming apparatus such as a multifunction machine, a copier, a printer, a scanner apparatus, and a facsimile apparatus. The multi-function device has at least two functions among a copy function, a printer function, a scanner function, and a facsimile function.

  First, the configuration of the sheet conveying apparatus of this embodiment will be described.

  FIG. 1 is a side view schematically illustrating an example of a mechanical configuration of the sheet conveying apparatus 100 according to the present embodiment. As shown in FIG. 1, the paper transport apparatus 100 includes a paper feed tray 102, a pickup roller 104, paper feed rollers 106a and 106b, a transport path 108, transport rollers 110a and 110b, a transmission sensor 112, and a reception. Sensor 114. The pickup roller 104, the paper feed rollers 106a and 106b, and the transport rollers 110a and 110b are rotationally driven by a driving device (not shown).

  A plurality of sheets are stacked and stored in the sheet feed tray 102. The pickup roller 104 is in contact with the paper P positioned at the uppermost part of the paper feed tray 102, and picks up the paper P in contact with the pickup roller 104 by rotating counterclockwise.

  The feed rollers 106a and 106b rotate counterclockwise and clockwise, respectively, thereby feeding the paper P picked up by the pickup roller 104, and transporting the transport path 108 to the transport rollers 110a and 110b. send.

  The conveyance rollers 110a and 110b rotate in the clockwise direction and the counterclockwise direction, respectively, and further convey the paper P sent from the paper supply rollers 106a and 106b on the conveyance path 108.

  The transmission sensor 112 and the reception sensor 114 are positioned to face each other with the conveyance path 108 interposed therebetween. The transmission sensor 112 is a sensor that transmits ultrasonic waves, and the reception sensor 114 is a sensor that receives ultrasonic waves transmitted by the transmission sensor 112. The ultrasonic wave received by the reception sensor 114 is attenuated as it passes through the air layer or the paper P, and is used for various detections such as detection of double feeding of paper by a detection unit described later. In the present embodiment, the transmission sensor 112 and the reception sensor 114 are movable, and the distance between the transmission sensor 112 and the reception sensor 114 is variable.

  FIG. 2 is a schematic diagram illustrating an example of the transmission sensor 112 and the reception sensor 114 of the present embodiment. As shown in FIG. 2, for example, the transmission sensor 112 transmits ultrasonic waves to the paper P being sent on the conveyance path 108 by the conveyance rollers 110 a and 110 b, and the reception sensor 114 has passed through the paper P. Receive ultrasound. The ultrasonic wave that has passed through the paper P received by the receiving sensor 114 is used for detecting double feeding of paper by a detection unit described later.

  The paper P sent from the transport rollers 110a and 110b passes through the positions of the transmission sensor 112 and the reception sensor 114, and then an image is transferred by an image forming unit (not shown) to form (print) the image.

  Further, the paper transport apparatus 100 does not have to have all of the above-described mechanical configurations as essential configurations, and may have a configuration in which some of them are omitted.

  FIG. 3 is a block diagram illustrating an example of an electrical configuration of the sheet conveying apparatus 100 according to the present embodiment. As shown in FIG. 3, the paper transport apparatus 100 includes a detection unit 120, an operation display unit 150, and a control unit 160.

  The detection unit 120 performs various detections such as detection of double feeding of sheets conveyed through the conveyance path 108, detection of presence / absence of sheets in the conveyance path 108, and detection of occurrence of abnormality in the transmission sensor 112 and the reception sensor 114. The detection unit 120 includes an oscillation unit 122, a burst wave generation unit 124, an amplification unit 126, a transmission sensor 112, a reception sensor 114, an amplification unit 128, a double feed determination unit 136, and a paper presence / absence determination unit 138. The abnormality determination unit 140 is provided.

  The oscillation unit 122 receives a detection request from the control unit 160 and generates a resonance frequency of the transmission sensor 112. The oscillating unit 122 is, for example, a 440 KHz oscillator, and generates a resonance frequency of 220 KHz.

  The burst wave generation unit 124 generates an output burst wave having an arbitrary wave number based on the resonance frequency generated by the oscillation unit 122. For example, the burst wave generating unit 124 generates an output burst wave having 8 oscillation pulses.

  The amplifying unit 126 amplifies the output burst wave generated by the burst wave generating unit 124 and can be realized by an operational amplifier, for example. For example, the amplification unit 126 amplifies the drive voltage of the output burst wave generated by the burst wave generation unit 124 to 24V.

  The transmission sensor 112 converts the output burst wave amplified by the amplification unit 126 into an ultrasonic wave and transmits the ultrasonic wave. For example, the transmission sensor 112 transmits ultrasonic waves under conditions such as a driving frequency of 220 KHz, a driving voltage of 24 V, and the number of oscillation pulses of 8 waves.

  The reception sensor 114 receives the ultrasonic wave transmitted from the transmission sensor 112 and outputs it to the amplification unit 128. For example, the reception sensor 114 outputs an output value obtained by converting the received ultrasonic wave into a potential to the amplification unit 128.

  The amplification unit 128 amplifies the output value from the reception sensor 114 by a predetermined amplification amount, and can be realized by an operational amplifier, for example. The amplification unit 128 includes a double feed determination amplification unit 130, a paper presence / absence determination amplification unit 132, and an abnormality determination amplification unit 134.

  The multifeed determination amplifying unit 130 outputs the ultrasonic wave received by the reception sensor 114, the maximum attenuation ultrasonic wave when passing under the condition that the attenuation amount is maximum and passes through one sheet of paper. Amplify with the amount of amplification for double feed determination that amplifies up to. Specifically, the multifeed determination amplifying unit 130 receives the ultrasonic wave received by the reception sensor 114 (the output value from the reception sensor 114) and the maximum attenuation ultrasonic wave when passing (the maximum attenuation ultrasonic wave when passing). The output value from the reception sensor 114 is amplified by the double feed determination amplification amount that is amplified to the power supply voltage of the operational amplifier, and is output to the double feed determination unit 136.

Here, the maximum attenuation ultrasonic wave when passing is at least one of the following (1) to (4).
(1) Ultrasonic waves received by the receiving sensor 114 after passing through one sheet of the maximum sheet basis weight conveyed through the conveying path 108 (2) Sensitivity characteristics of the receiving sensor 114 passing through one sheet Ultrasonic wave received at the lower limit (3) Ultrasonic wave received by the receiving sensor 114 passing through one sheet and distant from the transmitting sensor 112 (4) Transmitted at the minimum wave drive voltage value of the output burst wave Ultrasonic waves transmitted from the sensor 112 and passed through one sheet of paper and received by the reception sensor 114

  In the present embodiment, the maximum attenuation ultrasonic wave at the time of passing is described as an ultrasonic wave satisfying all of (1) to (4), but is not limited to this, and (1) to (4) It is sufficient that the ultrasonic wave satisfies at least one of the following.

  FIG. 4 is a diagram illustrating an example of the ultrasonic wave amplified by the multifeed determination amplifying unit 130. Specifically, the reception sensor 114 receives the ultrasonic wave that has passed through one sheet P on the conveyance path 108. The pulse output value obtained by amplifying the output value from is multiplied by the double feed determination amplification amount is shown. As shown in FIG. 4, the output value from the reception sensor 114 that has received the ultrasonic wave that has passed through the paper P is amplified to 5 V, which is the power supply voltage of the operational amplifier.

  This is because the attenuation amount of the ultrasonic wave that has passed through the paper P is an attenuation amount that is equal to or less than the maximum attenuation ultrasonic wave during passage, and the double feed determination amplification amount is a condition that the attenuation amount is maximum when passing through one sheet of paper. This is because the amount of amplification that amplifies the passing-through maximum attenuation ultrasonic wave received below to the power supply voltage of the operational amplifier. In other words, since the double feed determination amplification amount is an amplification amount that amplifies the maximum attenuation ultrasonic wave during passage up to the power supply voltage of the operational amplifier, the ultrasonic wave that has passed through the paper P that has an attenuation amount equal to or less than the maximum attenuation ultrasonic wave during passage is used. The received output value from the reception sensor 114 is amplified to the power supply voltage of the operational amplifier. Actually, if the attenuation amount of the ultrasonic wave that has passed through the paper P is smaller than the attenuation amount of the maximum attenuation ultrasonic wave during passage, the pulse output value amplified by the multifeed determination amplification unit 130 will be saturated. However, no change occurs in the pulse output value itself output from the double feed determination amplification unit 130. On the other hand, in the case of multi-feed paper, the ultrasonic wave passes through the paper twice or more, and the attenuation amount of the ultrasonic wave becomes larger than the attenuation amount of the maximum attenuation ultrasonic wave at the time of passage. Even if it is amplified by the amount, the power supply voltage of the operational amplifier is not amplified, and a pulse output value as shown in FIG. 4 cannot be obtained.

  The paper presence / absence determination amplifying unit 132 outputs the ultrasonic wave received by the receiving sensor 114 to the output upper limit value when the non-passing maximum attenuation ultrasonic wave is received under the condition that the paper does not pass through and the attenuation amount is maximum. Amplification is performed with the amplification amount for determining whether or not to amplify paper. Specifically, the paper presence / absence determination amplifying unit 132 converts the ultrasonic wave received by the reception sensor 114 (the output value from the reception sensor 114) into the non-passing maximum attenuation ultrasonic wave (the non-passing maximum attenuation ultrasonic wave). The received output value from the reception sensor 114 is amplified by the amplification amount for determining the presence / absence of paper up to the power supply voltage of the operational amplifier, and is output to the paper presence / absence determination unit 138.

Here, the non-passing maximum attenuation ultrasonic wave is an ultrasonic wave of at least one of the following (5) to (7).
(5) Ultrasonic wave received by the lower limit of the sensitivity characteristic of the reception sensor 114 without passing through the paper (6) Ultrasonic wave received by the receiving sensor 114 not passing through the paper and the maximum distance away from the transmission sensor 112 (7 ) Ultrasonic waves transmitted by the transmission sensor 112 at the minimum wave drive voltage value of the output burst wave and received by the reception sensor 114 without passing through the paper

  In the present embodiment, the non-passing maximum attenuation ultrasonic wave is described as an ultrasonic wave satisfying all of (5) to (7), but is not limited to this, and (5) to ( It is sufficient that the ultrasonic wave satisfies at least one of 7).

  FIG. 5 is a diagram illustrating an example of the ultrasonic wave amplified by the paper presence / absence determination amplifying unit 132. Specifically, the output value from the reception sensor 114 that has received the ultrasonic wave that does not pass through the paper is determined as the paper presence / absence determination. The pulse output value amplified by the amplification amount for use is shown. As shown in FIG. 5, the output value from the reception sensor 114 that has received the ultrasonic waves that do not pass through the paper is amplified to 5 V, which is the power supply voltage of the operational amplifier.

  This is because the amount of attenuation of ultrasonic waves that do not pass through the paper is less than the maximum attenuation ultrasonic wave during non-passage, and the amount of amplification for paper presence / absence determination is the condition that the paper passes through the paper and the amount of attenuation is maximum. This is because the amount of amplification that amplifies the non-passing maximum attenuated ultrasonic wave received at 1 to the power supply voltage of the operational amplifier. In other words, the paper presence / absence determination amplification amount is an amplification amount that amplifies the non-passing maximum attenuation ultrasonic wave up to the power supply voltage of the operational amplifier. The output value from the reception sensor 114 that has received the sound wave is amplified to the power supply voltage of the operational amplifier. Actually, if the attenuation amount of the ultrasonic wave that does not pass through the paper is smaller than the attenuation amount of the maximum attenuation ultrasonic wave when the paper does not pass through, the pulse output value amplified by the paper presence / absence determination amplification unit 132 is saturated. However, the pulse output value itself output from the paper presence / absence determination amplifying unit 132 does not change. On the other hand, when the ultrasonic wave passes through the paper, the attenuation amount of the ultrasonic wave is larger than the attenuation amount of the maximum attenuation ultrasonic wave when it does not pass. Thus, the pulse output value as shown in FIG. 5 cannot be obtained.

  The abnormality determination amplification unit 134 amplifies the ultrasonic wave received by the reception sensor 114 with an abnormality determination amplification amount that amplifies the non-passing maximum attenuated ultrasonic wave to a value that can be determined as abnormal. Specifically, the abnormality determination amplifying unit 134 receives the ultrasonic wave (output value from the reception sensor 114) received by the reception sensor 114, the non-passing maximum attenuation ultrasonic wave (the non-passing maximum attenuation ultrasonic wave). The peak-to-peak value of the output value from the reception sensor 114) is amplified by an abnormality determination amplification amount that amplifies the voltage to a predetermined voltage that can be determined to be abnormal below the power supply voltage of the operational amplifier, and is output to the abnormality determination unit 140.

  FIG. 6 is a diagram illustrating an example of the ultrasonic wave amplified by the abnormality determination amplification unit 134. Specifically, the output value from the reception sensor 114 that has received the ultrasonic wave that does not pass through the paper is amplified for abnormality determination. The pulse output value amplified by the quantity is shown. As shown in FIG. 6, the peak-to-peak value of the output value from the reception sensor 114 that has received the ultrasonic wave that does not pass through the paper is amplified to about 4 V, which is a predetermined voltage that can be determined to be abnormal below the power supply voltage of the operational amplifier. ing.

  This is because the attenuation amount of the ultrasonic wave that does not pass through the paper is equal to or lower than the maximum attenuation ultrasonic wave when the paper does not pass. This is because the amount of amplification that amplifies the received non-passing maximum attenuated ultrasonic wave to a predetermined voltage that can be determined as abnormal below the power supply voltage of the operational amplifier. That is, the abnormality determination amplification amount is an amplification amount that amplifies the non-passing maximum attenuated ultrasonic wave to a predetermined voltage that can be determined to be abnormal below the power supply voltage of the operational amplifier. If no abnormality has occurred, the peak-to-peak value of the output value from the reception sensor 114 that has received the ultrasonic wave that has not passed through the paper whose attenuation is equal to or less than the maximum attenuation ultrasonic wave when not passing is a predetermined value that can be determined as abnormal. It will be amplified to voltage. On the other hand, when an abnormality such as sensitivity deterioration occurs in at least one of the transmission sensor 112 and the reception sensor 114, the attenuation amount of the ultrasonic wave is larger than the attenuation amount of the maximum attenuation ultrasonic wave when not passing, so that the abnormality determination Even if it amplifies by the amplification amount for use, it does not amplify to a predetermined voltage that can be determined to be abnormal below the power supply voltage of the operational amplifier, and a pulse output value as shown in FIG.

  The amplification processing by the double feed determination amplification unit 130, the amplification processing by the paper presence determination amplification unit 132, and the amplification processing by the abnormality determination amplification unit 134 may be performed in parallel, or only one of them. May be performed.

  The double feed determination unit 136 integrates the ultrasonic waves amplified by the double feed determination amplification unit 130, compares the integrated value with the double feed determination threshold value, and the paper P being transported through the transport path 108 is overlapped. It is a circuit that determines whether or not the data is being sent. Specifically, the double feed determination unit 136 integrates the pulse output value output from the double feed determination amplification unit 130, and if the integrated value exceeds the double feed determination threshold, the double feed determination unit 136 is transported through the transport path 108. It is determined that the paper P being fed is not double fed. On the other hand, if the integrated value is equal to or less than the double feed determination threshold, the double feed determination unit 136 determines that the paper P being transported on the transport path 108 is being double transported. Then, the double feed determination unit 136 outputs the double feed determination result to the control unit 160.

  FIG. 7 is a diagram illustrating an example of an ultrasonic wave integrated by the double feed determination unit 136, and specifically shows a level output value obtained by integrating the pulse output value shown in FIG. In the example illustrated in FIG. 7, the level output value integrated by the double feed determination unit 136 exceeds the double feed determination threshold V1 that is the threshold voltage for double feed determination, and the double feed determination unit 136 causes the conveyance path 108 to be used. It is determined that the paper P being conveyed is not double-fed.

  FIG. 8 is a diagram illustrating an example of the ultrasonic wave integrated by the double feed determination unit 136. Specifically, the output from the reception sensor 114 that has received the ultrasonic wave that has passed through a plurality of multi-feed sheets. A level output value obtained by integrating the pulse output value obtained by amplifying the value by the double feed determination amplification amount is shown. In the example illustrated in FIG. 8, the level output value integrated by the double feed determination unit 136 is equal to or less than the double feed determination threshold V1 that is the threshold voltage for double feed determination. It is determined that the sheet P being conveyed is being double-fed.

  As described above, in the present embodiment, the level output value obtained by integrating the pulse output value output from the double feed determination amplifying unit 130 is used for comparison with the double feed determination threshold value. The output value differs greatly at the time of sending, and it can be easily determined whether the feed is double feed or non-double feed.

  In the present embodiment, an example has been described in which the multifeed determination unit 136 performs a multifeed determination by comparing the value obtained by integrating the ultrasonic waves amplified by the multifeed determination amplification unit 130 with a multifeed determination threshold. The multifeed determination method is not limited to this. For example, the double feed determination unit 136 directly compares the ultrasonic wave (pulse output value) amplified by the double feed determination amplification unit 130 with the double feed determination threshold value, and the ultrasonic wave (pulse output value) is used for double feed determination. The double feed determination may be performed by counting the number of times exceeding the threshold.

  The paper presence / absence determination unit 138 determines the presence / absence of paper (remaining paper) in the conveyance path 108 based on the ultrasonic wave received by the reception sensor 114. Specifically, the paper presence / absence determination unit 138 integrates the ultrasonic wave amplified by the paper presence / absence determination amplification unit 132, compares the integrated value with a paper presence / absence determination threshold value, and compares the integrated value with the paper ( This is a circuit for determining the presence or absence of a remaining sheet.

  Specifically, the paper presence / absence determination unit 138 integrates the pulse output value output from the paper presence / absence determination amplifying unit 132, and if the integrated value exceeds the paper presence / absence determination threshold value, the paper is present in the conveyance path. Judge that there is no. On the other hand, the sheet presence / absence determination unit 138 determines that there is a sheet in the conveyance path 108 if the integrated value is equal to or less than the sheet presence / absence determination threshold. Then, the paper presence / absence determination unit 138 outputs the paper presence / absence determination result to the control unit 160.

  FIG. 9 is a diagram illustrating an example of the ultrasonic wave integrated by the paper presence / absence determination unit 138, and specifically shows a level output value obtained by integrating the pulse output value shown in FIG. In the example shown in FIG. 9, the level output value integrated by the paper presence / absence determination unit 138 exceeds the paper presence / absence determination threshold V2 that is the threshold voltage for paper presence / absence determination. It is determined that there is no paper inside.

  FIG. 10 is a diagram illustrating an example of the ultrasonic wave integrated by the paper presence / absence determination unit 138. Specifically, the output value from the reception sensor 114 that has received the ultrasonic wave not passing through the paper is amplified for paper presence / absence determination. The level output value obtained by integrating the pulse output value amplified by the quantity is shown. In the example shown in FIG. 10, the level output value integrated by the paper presence / absence determination unit 138 is equal to or lower than the paper presence / absence determination threshold V2 that is the threshold voltage for paper presence / absence determination. It is determined that there is a sheet.

  As described above, in this embodiment, the level output value obtained by integrating the pulse output value output from the paper presence / absence determination amplification unit 132 is used for comparison with the paper presence / absence determination threshold value. The output value varies greatly depending on the time, and it can be easily determined whether or not there is a sheet in the conveyance path 108.

  In the present embodiment, the paper presence / absence determination unit 138 performs the paper presence / absence determination by comparing the value obtained by integrating the ultrasonic wave amplified by the paper presence / absence determination amplification unit 132 with the threshold for paper presence / absence determination. The paper presence / absence determination method is not limited to this. For example, the paper presence / absence determination unit 138 directly compares the ultrasonic wave (pulse output value) amplified by the paper presence / absence determination amplification unit 132 with a paper presence / absence determination threshold, and the ultrasonic wave (pulse output value) is used for paper presence / absence determination. The presence / absence determination of the sheet may be performed by counting the number of times exceeding the threshold.

  The abnormality determination unit 140 integrates the ultrasonic wave amplified by the abnormality determination amplification unit 134, compares the integrated value with the abnormality determination threshold value, and an abnormality occurs in at least one of the transmission sensor 112 and the reception sensor 114. It is a circuit that determines whether or not

  Specifically, the abnormality determination unit 140 integrates the pulse output value output from the abnormality determination amplification unit 134, and if the integrated value exceeds the abnormality determination threshold value, the transmission sensor 112 and the reception sensor 114 are sensitive. It is determined that no abnormality such as deterioration has occurred. On the other hand, if the integrated value is equal to or less than the abnormality determination threshold value, abnormality determination unit 140 determines that abnormality such as sensitivity degradation has occurred in at least one of transmission sensor 112 and reception sensor 114. Then, abnormality determination unit 140 outputs the abnormality determination result to control unit 160.

  FIG. 11 is a diagram illustrating an example of an ultrasonic wave integrated by the abnormality determination unit 140, and specifically shows a level output value obtained by integrating the pulse output value shown in FIG. In the example shown in FIG. 11, the level output value integrated by the abnormality determination unit 140 exceeds the abnormality determination threshold V3 that is the threshold voltage of the abnormality determination threshold, and the abnormality determination unit 140 transmits the transmission sensor 112 and the reception sensor. It is determined that no abnormality has occurred in 114.

  FIG. 12 is a diagram illustrating an example of the ultrasonic wave integrated by the abnormality determination unit 140. Specifically, the output value from the reception sensor 114 that has received the ultrasonic wave that does not pass through the paper is expressed as an abnormality determination amplification amount. A level output value obtained by integrating the amplified pulse output value is shown. In the example illustrated in FIG. 12, the level output value integrated by the abnormality determination unit 140 is equal to or lower than the abnormality determination threshold V3 that is the threshold voltage of the abnormality determination threshold, and the transmission sensor 112 and the reception sensor 114 are detected by the abnormality determination unit 140. It is determined that an abnormality has occurred in at least one of the above.

  As described above, in this embodiment, the level output value obtained by integrating the pulse output value output from the abnormality determination amplification unit 134 is used for comparison with the abnormality determination threshold value. The output values are greatly different from each other, and it is possible to easily determine whether an abnormality has occurred or not.

  In the present embodiment, an example in which the abnormality determination unit 140 performs abnormality determination by comparing the value obtained by integrating the ultrasonic wave amplified by the abnormality determination amplification unit 134 with the abnormality determination threshold is described. Is not limited to this. For example, the abnormality determination unit 140 compares the ultrasonic wave (pulse output value) amplified by the abnormality determination amplification unit 134 with the abnormality determination threshold value as it is, and the ultrasonic wave (pulse output value) exceeds the abnormality determination threshold value. The abnormality determination may be performed by counting the number of times.

  The operation display unit 150 (an example of a notification unit) is used by a user to input various operations and display various screens, and can be realized by a touch panel display or the like. The operation display unit 150 receives an instruction from the control unit 160 and reports the double feed determination result of the double feed determination unit 136, the paper presence / absence determination result of the paper presence / absence determination unit 138, or the abnormality determination result of the abnormality determination unit 140. For example, the operation display unit 150 displays that when the double feed determination result indicates double feed, or displays that when the paper presence / absence determination result indicates that there is paper (remaining paper). Or when the abnormality determination result indicates an abnormality. In addition, when the control unit 160 confirms that the output from at least one of the transmission sensor 112 and the reception sensor 114 causes abnormal oscillation, the operation display unit 150 receives an instruction from the control unit 160 and notifies that. indicate. In this embodiment, the notification by display has been described as an example. However, the notification mode is not limited to this, and notification by light using a light source or the like or notification by sound using a speaker or the like may be used. Good. In addition, the operation display unit 150 receives a paper transport (printing) start input from the user and notifies the control unit 160 of the input.

  The control unit 160 controls each unit of the paper transport apparatus 100 and can be realized by an existing control device such as a controller having a CPU (Central Processing Unit), a memory, and the like. When the control unit 160 receives a start input of paper conveyance (printing) from the operation display unit 150 and starts a print job, it makes a detection request to the detection unit 120. In addition, the control unit 160 receives an output such as a double feed determination result, a paper presence / absence determination result, or an abnormality determination result from the detection unit 120 and causes the operation display unit 150 to perform the above-described notification.

  In addition, the control unit 160 (an example of a confirmation unit) stops the paper conveyance device 100 and performs the transmission sensor 112 and reception in a state where the transmission sensor 112 does not transmit ultrasonic waves and the reception sensor 114 does not receive ultrasonic waves. It is confirmed whether the output from at least one of the sensors 114 causes abnormal oscillation.

  This is because, in the case of a general paper transport device, the input value to the transmission sensor and the output value from the reception sensor are amplified with a high gain, and shield processing is performed with a shielded cable or the like for noise reduction. This is to prevent the output from the transmission sensor or the reception sensor from causing an abnormal oscillation when the cable is disconnected or the shield clamp is disconnected, and the normal detection cannot be performed. The reason why the sheet conveying apparatus 100 is stopped is because reverberation of the transmission sensor 112 and the reception sensor 114 is taken into consideration.

  In addition, when the control unit 160 confirms that the output from at least one of the transmission sensor 112 and the reception sensor 114 causes abnormal oscillation, the control unit 160 causes the operation display unit 150 to perform the above-described notification.

  Note that the paper transport apparatus 100 does not have to have all the above-described electrical configurations as essential configurations, and may have a configuration in which some of them are omitted.

  Next, the operation of the sheet conveying apparatus of this embodiment will be described.

  FIG. 13 is a flowchart illustrating an example of a flow of a multi-feed detection process performed by the paper transport apparatus 100 according to the present embodiment.

  First, when the conveyance of the paper on the conveyance path 108 is started and a double feed detection request is made from the control unit 160, the transmission sensor 112 is transmitted by the burst wave generation unit 124 based on the resonance frequency generated by the oscillation unit 122. The output burst wave generated and amplified by the amplifying unit 126 is converted into an ultrasonic wave and transmitted (step S100).

  Subsequently, the reception sensor 114 receives the ultrasonic wave transmitted by the transmission sensor 112 and outputs it to the amplification unit 128 (step S102).

  Subsequently, the double feed determination amplifying unit 130 amplifies the ultrasonic wave received by the reception sensor 114 by the double feed determination amplification amount, and outputs it to the double feed determination unit 136 (step S104).

  Subsequently, the double feed determination unit 136 integrates the ultrasonic wave amplified by the double feed determination amplification unit 130, compares the integrated value with the double feed determination threshold value, and transports the paper being transported through the transport path 108. It is determined whether or not multiple feeds are being fed, and the double feed judgment result is output to the control unit 160 (step S106).

  Subsequently, when the double feed determination result output from the double feed determination unit 136 indicates double feed (Yes in step S108), the control unit 160 displays the fact on the operation display unit 150 and prints the sheet. Is informed that double feed is being carried (step S110).

  On the other hand, when the double feed determination result output from the double feed determination unit 136 does not indicate double feed (No in step S108), the control unit 160 does not perform the process of step S110.

  As described above, in this embodiment, the ultrasonic wave received by the reception sensor 114 is passed through one sheet and the maximum attenuation ultrasonic wave at the time of passage received under the condition that the attenuation amount is maximized is the output upper limit value. Amplify with the amount of amplification for double feed determination that amplifies up to. As a result, it is possible to eliminate fluctuations in the amount of attenuation of the ultrasonic waves that are affected by various factors such as the basis weight of the paper and the sensitivity characteristics of the receiver, from the ultrasonic waves amplified by the double feed determination amplification amount. When detecting the transmission, it is not necessary to perform control according to the fluctuation of the attenuation amount of the ultrasonic wave. For this reason, according to the present embodiment, it is possible to improve the detection accuracy of double feeding of paper without requiring complicated control.

  In addition, since data setting for performing control according to fluctuations in the attenuation amount of ultrasonic waves becomes unnecessary, erroneous detection due to human error such as a data setting error can be prevented.

  FIG. 14 is a flowchart illustrating an example of the flow of the procedure of the paper presence / absence detection process performed by the paper transport apparatus 100 according to the present embodiment.

  First, when a sheet presence / absence detection request is made from the control unit 160, the transmission sensor 112 generates an output burst generated by the burst wave generation unit 124 based on the resonance frequency generated by the oscillation unit 122 and amplified by the amplification unit 126. A wave is converted into an ultrasonic wave and transmitted (step S200).

  Subsequently, the reception sensor 114 receives the ultrasonic wave transmitted by the transmission sensor 112 and outputs it to the amplification unit 128 (step S202).

  Subsequently, the paper presence / absence determination amplifying unit 132 amplifies the ultrasonic wave received by the reception sensor 114 by the paper presence / absence determination amplification amount, and outputs the amplified ultrasonic wave to the paper presence / absence determination unit 138 (step S204).

  Subsequently, the paper presence / absence determination unit 138 integrates the ultrasonic wave amplified by the paper presence / absence determination amplification unit 132, compares the integrated value with a paper presence / absence determination threshold value, and determines the presence / absence of paper in the transport path 108. The paper presence / absence determination result is output to the controller 160 (step S206).

  Subsequently, when the sheet presence / absence determination result output from the sheet presence / absence determination unit 138 indicates that there is a sheet (Yes in step S208), the control unit 160 displays the fact on the operation display unit 150 to indicate the sheet. (Step S210).

  On the other hand, when the paper presence / absence determination result output from the paper presence / absence determination unit 138 does not indicate the presence of paper (No in step S208), the control unit 160 does not perform the process of step S210.

  As described above, in the present embodiment, the ultrasonic wave received by the reception sensor 114 is converted from the maximum attenuation ultrasonic wave when not passing through the paper and the amount of attenuation to the maximum to the output upper limit value. Amplification is performed with the amplification amount for determining whether or not to amplify paper. As a result, it is possible to eliminate fluctuations in the attenuation amount of ultrasonic waves affected by various factors such as the sensitivity characteristics of the receiver from the ultrasonic waves amplified by the amplification amount for determining the presence / absence of paper. The control according to the fluctuation | variation of the attenuation amount of an ultrasonic wave becomes unnecessary. For this reason, according to the present embodiment, it is possible to improve the accuracy of detecting the presence or absence of a sheet without requiring complicated control.

  In addition, since the presence or absence of paper can be determined even if the paper has a hole in the paper, such as stock form paper, or the leading or trailing edge of the paper, the paper can be more reliably combined with the above-described double feed detection. It is possible to detect double feed in a certain state.

  FIG. 15 is a flowchart illustrating an example of a flow of an abnormality detection process performed by the paper conveying apparatus 100 according to the present embodiment.

  First, when an abnormality detection request is made from the control unit 160, the transmission sensor 112 generates an output burst wave generated by the burst wave generation unit 124 based on the resonance frequency generated by the oscillation unit 122 and amplified by the amplification unit 126. Is converted into an ultrasonic wave and transmitted (step S300).

  Subsequently, the reception sensor 114 receives the ultrasonic wave transmitted by the transmission sensor 112 and outputs it to the amplification unit 128 (step S302).

  Subsequently, the abnormality determination amplification unit 134 amplifies the ultrasonic wave received by the reception sensor 114 by the abnormality determination amplification amount, and outputs the amplified ultrasonic wave to the abnormality determination unit 140 (step S304).

  Subsequently, the abnormality determination unit 140 integrates the ultrasonic wave amplified by the abnormality determination amplifying unit 134, compares the integrated value with the abnormality determination threshold value, and determines at least one of the transmission sensor 112 and the reception sensor 114. It is determined whether or not an abnormality such as sensitivity deterioration has occurred, and the abnormality determination result is output to the control unit 160 (step S306).

  Subsequently, when the abnormality determination result output from the abnormality determination unit 140 indicates an abnormality (Yes in step S308), the control unit 160 displays the fact on the operation display unit 150 and the transmission sensor 112 and It is notified that an abnormality has occurred in at least one of the reception sensors 114 (step S310).

  On the other hand, when the abnormality determination result output from the abnormality determination unit 140 does not indicate an abnormality (No in step S308), the control unit 160 does not perform the process of step S310.

  As described above, in the present embodiment, the ultrasonic wave received by the reception sensor 114 can be determined to be abnormal when the non-passing maximum attenuated ultrasonic wave is received under conditions that do not pass through the paper and the attenuation amount is maximum. Amplify with the amplification amount for abnormality determination to amplify up to As a result, it is possible to eliminate fluctuations in the attenuation amount of the ultrasonic wave affected by various factors such as the sensitivity characteristic of the receiver from the ultrasonic wave amplified by the amplification amount for abnormality determination. When detecting this, the control according to the fluctuation | variation of the attenuation amount of an ultrasonic wave becomes unnecessary. For this reason, according to the present embodiment, it is possible to increase the accuracy of detecting abnormality of the transmission sensor 112 and the reception sensor 114 without requiring complicated control.

  Further, in the present embodiment, an abnormality such as sensitivity deterioration due to an external factor such as paper dust accumulated on the surfaces of the transmission sensor 112 and the reception sensor 114 can be detected, so that the transmission sensor 112 and the reception sensor 114 are notified by notifying the abnormality. It is possible to prompt the user to replace or clean the device.

  In addition, the control unit 160 stores the detection results of the abnormality of the transmission sensor 112 and the reception sensor 114 as a log and refers to the stored log, so that the user can quickly replace or clean the transmission sensor 112 and the reception sensor 114. It is possible to notify the user, and it is possible to make it possible for the user to respond before an abnormality occurs in the transmission sensor 112 and the reception sensor 114.

  Further, by combining with the above-described sheet presence / absence detection and double feed detection, more reliable double feed detection becomes possible.

  FIG. 16 is a flowchart illustrating an example of a flow of an initial check process performed by the paper conveying apparatus 100 according to the present embodiment. Note that the initial check process shown in FIG. 16 is performed after the paper jammed in the conveyance path 108 is removed or after the paper conveyance device 100 is activated.

  First, the control unit 160 stops the paper conveyance device 100 and at least one of the transmission sensor 112 and the reception sensor 114 in a state where the transmission of the ultrasonic wave by the transmission sensor 112 and the reception of the ultrasonic wave by the reception sensor 114 are not performed. It is confirmed whether or not the output from the head causes abnormal oscillation (step S400).

  Subsequently, when the control unit 160 confirms that the output from at least one of the transmission sensor 112 and the reception sensor 114 causes abnormal oscillation (Yes in step S402), the control display unit 160 notifies the operation display unit 150 to that effect. Is displayed to notify that the output from at least one of the transmission sensor 112 and the reception sensor 114 is causing abnormal oscillation (step S404). In this case, since the execution of the print job performed after the initial check process is stopped, the detection process accompanying the execution of the print job such as the double feed detection process is not performed.

  On the other hand, when the control unit 160 confirms that the outputs from the transmission sensor 112 and the reception sensor 114 do not cause abnormal oscillation (No in step S402), the control unit 160 starts the operation of the sheet conveying device 100, and transmits the transmission sensor. Transmission of the ultrasonic wave from 112 is started (step S406).

  Subsequently, the control unit 160 receives the output of the abnormality determination result from the abnormality determination unit 140, and when the abnormality determination result indicates an abnormality (Yes in step S408), displays that fact on the operation display unit 150. Then, it is notified that an abnormality has occurred in at least one of the transmission sensor 112 and the reception sensor 114 (step S410). Also in this case, since the execution of the print job performed after the initial check process is stopped, the detection process accompanying the execution of the print job such as the double feed detection process is not performed.

  On the other hand, when the abnormality determination result does not indicate abnormality (No in step S408), the control unit 160 receives the output of the sheet presence / absence determination result from the sheet presence / absence determination unit 138, and the sheet presence / absence determination result is the sheet (remaining paper). ) If yes (Yes in Step S412), the fact is displayed on the operation display unit 150 to notify that there is a remaining sheet (Step S414). Also in this case, since the execution of the print job performed after the initial check process is stopped, the detection process accompanying the execution of the print job such as the double feed detection process is not performed.

  On the other hand, when the paper presence / absence determination result indicates that there is no paper (remaining paper) (No in step S412), the control unit 160 ends the initial check process, executes the print job, and detects double feed. Detection processing associated with execution of a print job such as processing is performed.

  As described above, in this embodiment, after the paper jammed in the conveyance path 108 is removed or after the paper conveyance device 100 is activated, the above-described initial check process is performed, and the initial check process is normally completed. In addition to executing a print job, detection processing associated with execution of the print job such as double feed detection processing is performed. Therefore, according to this embodiment, abnormal oscillation caused by cable disconnection or shield clamp disconnection, deterioration of sensitivity characteristics caused by paper dust generated at the time of printing, and occurrence of printing jam, the conveyance path 108 is caused. Double feed detection processing is performed after checking for the presence of remaining paper that may cause paper breakage when removing jammed paper, making it possible to perform double feed detection in an environment suitable for ultrasonic double feed detection. Highly reliable double feed detection is possible.

  In addition, the control part 160 preserve | saves the content (error content) to alert | report as a log, when making the operation display part 150 alert | report.

  FIG. 17 is a block diagram illustrating an example of a hardware configuration of an image forming apparatus 900 to which the sheet conveying apparatus 100 of the present embodiment is applied. As shown in FIG. 17, an image forming apparatus 900 according to the present embodiment has a configuration in which a controller 910 and an engine unit (Engine) 960 are connected by a PCI (Peripheral Component Interconnect) bus. The controller 910 is a controller that controls control of the entire image forming apparatus 900, drawing, communication, and input from the operation display unit 920. The engine unit 960 is a printer engine that can be connected to a PCI bus, and is, for example, a monochrome plotter, a 1-drum color plotter, a 4-drum color plotter, a scanner, or a fax unit. The engine unit 960 includes an image processing part such as error diffusion and gamma conversion in addition to a so-called engine part such as a plotter.

  The controller 910 includes a CPU 911, a north bridge (NB) 913, a system memory (MEM-P) 912, a south bridge (SB) 914, a local memory (MEM-C) 917, and an ASIC (Application Specific Integrated Circuit). 916 and a hard disk drive (HDD) 918, and the North Bridge (NB) 913 and the ASIC 916 are connected by an AGP (Accelerated Graphics Port) bus 915. The MEM-P 912 further includes a ROM 912a and a RAM 912b.

  The CPU 911 controls the entire image forming apparatus 900, has a chip set including the NB 913, the MEM-P 912, and the SB 914, and is connected to other devices via the chip set.

  The NB 913 is a bridge for connecting the CPU 911 to the MEM-P 912, SB 914, and the AGP bus 915, and includes a memory controller that controls reading and writing to the MEM-P 912, a PCI master, and an AGP target.

  The MEM-P 912 is a system memory used as a memory for storing programs and data, a memory for developing programs and data, a memory for drawing printers, and the like, and includes a ROM 912a and a RAM 912b. The ROM 912a is a read-only memory used as a memory for storing programs and data, and the RAM 912b is a writable and readable memory used as a program / data development memory, a printer drawing memory, and the like.

  The SB 914 is a bridge for connecting the NB 913 to a PCI device and a peripheral device. The SB 914 is connected to the NB 913 via a PCI bus, and a network interface (I / F) unit and the like are also connected to the PCI bus.

  The ASIC 916 is an IC (Integrated Circuit) for image processing having hardware elements for image processing, and has a role of a bridge for connecting the AGP bus 915, the PCI bus, the HDD 918, and the MEM-C 917, respectively. The ASIC 916 includes a PCI target and an AGP master, an arbiter (ARB) that forms the core of the ASIC 916, a memory controller that controls the MEM-C 917, and a plurality of DMACs (Direct Memory) that perform image data rotation by hardware logic and the like. Access Controller) and a PCI unit that performs data transfer between the engine unit 960 via the PCI bus. The ASIC 916 is connected to an FCU (Fax Control Unit) 930, a USB (Universal Serial Bus) 940, and an IEEE 1394 (the Institute of Electrical and Electronics Engineers 1394) interface 950 via a PCI bus. The operation display unit 920 is directly connected to the ASIC 916.

  The MEM-C 917 is a local memory used as a copy image buffer and a code buffer, and the HDD 918 is a storage for storing image data, programs, font data, and forms.

  The AGP bus 915 is a bus interface for a graphics accelerator card proposed for speeding up graphics processing. The AGP bus 915 speeds up the graphics accelerator card by directly accessing the MEM-P 912 with high throughput. It is.

DESCRIPTION OF SYMBOLS 100 Paper conveying apparatus 102 Paper feed tray 104 Pickup roller 106a, 106b Paper feed roller 108 Carriage path 110a, 110b Carrying roller 112 Transmission sensor 114 Reception sensor 120 Detection part 122 Oscillation part 124 Burst wave generation part 126 Amplification part 128 Amplification part 130 Duplication Feed determination amplifying unit 132 Paper presence / absence determination amplification unit 134 Abnormality determination amplification unit 136 Double feed determination unit 138 Paper presence / absence determination unit 140 Abnormality determination unit 150 Operation display unit 160 Control unit 900 Image forming apparatus 910 Controller 911 CPU
912 System memory 912a ROM
912b RAM
913 North Bridge 914 South Bridge 915 AGP Bus 916 ASIC
917 Local memory 918 Hard disk drive 920 Operation display unit 930 FCU
940 USB
950 IEEE1394 interface 960 engine part

JP 2006-211892 A

Claims (13)

A paper transport device,
A transmission sensor for transmitting an ultrasonic wave after the paper jammed in the conveyance path for conveying the paper is removed or after the paper conveyance device is activated;
A reception sensor that is positioned opposite to the transmission sensor across the conveyance path and that receives the ultrasonic waves transmitted from the transmission sensor;
Based on the ultrasonic wave received by the reception sensor, a paper presence / absence determination unit that determines the presence / absence of remaining paper in the conveyance path;
A sheet conveying apparatus comprising:   2. The apparatus according to claim 1, further comprising a confirmation unit configured to confirm whether or not an output of at least one of the transmission sensor and the reception sensor does not cause abnormal oscillation before the transmission sensor transmits the ultrasonic wave. Item 2. The paper conveyance device according to Item 1.   The paper conveying apparatus according to claim 2, wherein the transmission sensor transmits the ultrasonic wave when it is confirmed by the confirmation unit that no abnormal oscillation has occurred. Amplification amount for abnormality determination that amplifies the ultrasonic wave received by the reception sensor to a value that can be determined to be abnormal when the non-passage maximum attenuation ultrasonic wave is received under the condition that the attenuation amount is maximum and the sheet does not pass. Amplifying means for abnormality determination to be amplified;
Whether or not an abnormality has occurred in at least one of the transmission sensor and the reception sensor by comparing the ultrasonic wave amplified by the abnormality determination amplification means or a value obtained by integrating the ultrasonic wave with a threshold value for abnormality determination The sheet conveying apparatus according to any one of claims 1 to 3, further comprising abnormality determining means for determining whether or not.   The paper presence / absence determining means determines the presence / absence of remaining paper in the transport path based on the ultrasonic wave received by the reception sensor when the abnormality determining means determines that no abnormality has occurred. The sheet conveying apparatus according to claim 4, wherein: A paper presence / absence determination amplifying unit that amplifies the ultrasonic wave received by the reception sensor by a paper presence / absence determination amplification amount that amplifies the non-passing maximum attenuation ultrasonic wave to an output upper limit;
The paper presence / absence determination means compares the ultrasonic wave amplified by the paper presence / absence determination amplification means or a value obtained by integrating the ultrasonic wave with a paper presence / absence determination threshold value, and determines the presence / absence of remaining paper in the conveyance path. 6. The paper conveying apparatus according to claim 4, wherein the paper conveying device is determined.   7. The non-passing maximum attenuation ultrasonic wave is an ultrasonic wave that has been received at a lower limit value of the sensitivity characteristic of the reception sensor without passing through a sheet. Paper transport device.   8. The non-passing maximum attenuated ultrasonic wave is an ultrasonic wave that is received by the receiving sensor that does not pass through a sheet and is separated from the transmitting sensor by a maximum distance. The paper conveying apparatus as described.   9. The non-passing maximum attenuation ultrasonic wave is an ultrasonic wave that is transmitted at a minimum drive voltage value of the transmission sensor and is received by the reception sensor without passing through a sheet. The sheet conveying apparatus according to item 1. The abnormality determination amplifying means is an operational amplifier,
10. The sheet conveying apparatus according to claim 4, wherein the abnormality determination possible value is a predetermined voltage equal to or lower than a power supply voltage of the operational amplifier. The paper presence / absence judging amplification means is an operational amplifier,
The paper conveying apparatus according to claim 6, wherein the output upper limit value is a power supply voltage of the operational amplifier.   12. The paper conveyance according to claim 1, further comprising a notification unit that notifies that there is a remaining sheet when it is determined by the sheet presence / absence determination unit that there is a remaining sheet. apparatus.   An image forming apparatus comprising the sheet conveying device according to claim 1.

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