JP2016109770A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a generation source of noise to be easily estimated when the noise is generated in potential of a main body frame in an electronic device.SOLUTION: An electronic device 1 comprises: a main body frame; a plurality of units (unit 12a and the like) that are electrically connected to the main body frame; a storage unit 11 that stores an operation time required for an operation of each unit; and a control unit 10 that inputs a potential signal indicative of potential of the main body frame, detects a cycle of noise of the potential signal, compares the detected cycle with the operation time, and estimates that the unit with the operation time corresponding to the cycle is a noise generation source.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic apparatus such as an image forming apparatus.

  2. Description of the Related Art Image forming apparatuses such as copying machines and multi-function machines are equipped with units that require high voltage by an internal booster circuit or high voltage output from a power supply unit, such as a developing unit and a transfer unit. In such a unit, abnormal output such as leakage (abnormal discharge) may occur due to the state of a load (contact failure, etc.) connected to the inside. In addition, when the shaft of the transport roller or the like on the paper transport path is not properly grounded and its potential is unstable, the charge on the paper due to static electricity may be abnormally discharged to the shaft.

  When such abnormal output occurs, noise is generated in the potential of the frame of the main body of the image forming apparatus that is grounded, and malfunctions such as malfunction of various sensors mounted on the image forming apparatus and flickering of the operation panel occur. In some cases, however, the operation of the apparatus must be stopped.

  In the image forming apparatus described in Patent Document 1, a plurality of detection sensors that output a signal of a level corresponding to the presence / absence of a conveyance sheet are arranged on the sheet conveyance path and the signal level is changed to a level at which the sheet is detected. When the time interval until the level returns to the original level is shorter than the time required for the sheet to pass through the detection sensor, it is determined that the detection sensor detects noise due to lightning.

  In the image forming apparatus described in Patent Document 2, a potential of a power supply line to which a voltage from a DC power supply is applied is set to a predetermined value output from a second DC power supply that is electrically independent from the DC power supply. When the former becomes higher than the latter due to the occurrence of leak noise due to poor terminal contact, the operation of the image forming apparatus is stopped or an abnormality is notified.

Japanese Patent Laid-Open No. 11-59963 JP 2000-47531 A

  When a trouble due to noise as described above occurs, a serviceman confirms the phenomenon of the trouble, and the trouble is caused by which component (for example, transfer belt, photosensitive drum, transfer roller, shaft, etc.). It is necessary to identify what to do. However, it is very difficult to specify the source of such noise, and there are many places that depend on the intuition and experience of service personnel.

  Further, in the technique described in Patent Document 1, although the generation of noise can be detected by the detection sensor, when noise is generated in the potential of the frame of the main body of the image forming apparatus, which detection sensor is basically installed. Since the generation of noise is detected in step 1, the source of the noise cannot be specified.

  In the technique described in Patent Document 2, when noise occurs in the potential of the frame of the main body of the image forming apparatus, it is only possible to detect the occurrence, and it is difficult to specify the source of the noise. is there.

  Further, the above-described problem can occur not only in the image forming apparatus but also in other types of electronic devices. In general, other types of electronic devices do not include a conveyance roller. However, even in that case, there is a unit that is supplied with power by the power supply unit. Problems can arise.

  The present invention has been made in view of the above-described actual situation, and an object of the present invention is to make it possible to easily estimate the generation source of noise in the electronic device when noise is generated in the potential of the frame of the main body. Is to make it.

  In order to solve the above-described problem, a first technical means of the present invention is an electronic device including a main body frame and a plurality of units electrically connected to the main body frame. The storage unit that stores the operation time required for the operation and the potential signal indicating the potential of the main body frame are input, the period of noise of the potential signal is detected, the detected period is compared with the operation time, and the period is And a control unit that estimates that the unit having the corresponding operation time is a noise generation source.

  According to a second technical means of the present invention, in the first technical means, the control unit determines the presence or absence of the noise based on whether or not the potential of the main body frame is equal to or higher than a reference potential. It is.

  According to a third technical means of the present invention, in the first or second technical means, a plurality of the operation times of the unit are stored according to the operation content of the electronic device. .

  According to a fourth technical means of the present invention, in the third technical means, the control unit estimates the noise generation source by comparing the period with the operation time corresponding to the operation content being executed. It is characterized by that.

  According to a fifth technical means of the present invention, in any one of the first to fourth technical means, a notification unit that notifies information indicating the noise generation source estimated by the control unit is provided. It is a thing.

  According to a sixth technical means of the present invention, in any one of the first to fifth technical means, the electronic device is an image forming apparatus.

  A seventh technical means of the present invention is the sixth technical means, comprising: a paper transport path having a plurality of transport rollers; and a sensor that detects a paper being transported at a predetermined position in the paper transport path. The storage unit stores a required time, and the required time is a time required from the time when the sheet is detected by the sensor to reach each conveyance roller or to pass through each conveyance roller, Alternatively, the time required for the sensor to detect the paper from the time when the paper reaches or passes through each transport roller, and the control unit detects the paper using the sensor. A time interval from when the potential signal is generated to when the noise of the potential signal is generated is detected, the detected time interval is compared with the required time, and the time before the required time that matches the time interval is detected. Is obtained by the estimating means estimates the conveying roller and the a noise source.

  According to an eighth technical means of the present invention, in the seventh technical means, a plurality of the required times of the transport rollers are stored according to the operation content of the electronic device.

  According to a ninth technical means of the present invention, in the eighth technical means, the control unit estimates the noise generation source by comparing the time interval with the required time corresponding to the operation content being executed. It is characterized by doing.

  According to the present invention, in the electronic device, when noise is generated in the potential of the frame of the main body, the generation source of the noise can be easily estimated.

It is a block diagram which shows one structural example of the electronic device which concerns on the 1st Embodiment of this invention. It is a circuit diagram which shows an example of the principal part in the electronic device of FIG. FIG. 3 is a diagram illustrating a potential of a main body frame and an output potential of an operational amplifier when the electronic apparatus of FIG. 2 is normal. FIG. 3 is a diagram illustrating a potential of a main body frame and an output potential of an operational amplifier when noise occurs in the electronic device of FIG. 2. It is a figure which shows an example of the time information of the memory | storage part in the electronic device of FIG. It is a flowchart for demonstrating an example of the noise generation source estimation process in the electronic device of FIG. FIG. 2 is a cross-sectional view illustrating a configuration example of an image forming apparatus as an example of the electronic apparatus of FIG. 1. It is a figure which shows an example of the time information memorize | stored in the memory | storage part in the image forming apparatus of FIG. FIG. 7 is a diagram schematically illustrating a sheet conveyance path in the image forming apparatus of FIG. 6. FIG. 7 is a diagram schematically illustrating another example of a sheet conveyance path in the image forming apparatus of FIG. 6. It is a figure which shows an example of the time information memorize | stored in the memory | storage part in the image forming apparatus as an electronic device which concerns on the 3rd Embodiment of this invention. It is a figure which shows the other example of the time information memorize | stored in the memory | storage part in the image forming apparatus as an electronic device which concerns on the 3rd Embodiment of this invention.

  An electronic apparatus according to the present invention is an apparatus that includes a frame of a main body and a plurality of units that are frame-connected to the frame. Examples of such electronic devices include various types of electronic devices such as an image forming apparatus, a television device, an air conditioner, an air purifier, a refrigerator, and a washing machine. Hereinafter, various embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a configuration example of an electronic device according to the present embodiment.

  The electronic device 1 according to the present embodiment includes a main body frame (not shown) and a plurality of units (units 12a, 12b, 12c, etc.) electrically connected to the main body frame (frame connection). Of course, the electronic apparatus 1 also includes a power supply unit (not shown), and this power supply unit is also frame-connected to the main body frame. Of course, this body frame is made of metal. In addition, at least a part of the plurality of units is a load unit that operates by supplying power from the power supply unit.

  Moreover, the electronic device 1 includes a control unit 10 that controls the entire electronic device 1 and a storage unit 11 as main features. The storage unit 11 stores the operation time required for the operation of each unit. Here, the information indicating the operation time will be described as time information 11a.

  The control unit 10 inputs a signal (potential signal) indicating the potential of the main body frame. It is preferable that the main body frame can be grounded. In the following description, it is assumed that the electronic device 1 is basically grounded and used during its operation. Therefore, the potential signal will be described as a “ground (GND) level signal”. However, since it is only necessary to be able to detect the noise described later, it is only necessary to handle a potential signal indicating the potential of the main body frame even if it is not grounded.

  If abnormal output such as abnormal discharge (leakage) occurs due to the internal load status (contact failure, etc.) in the unit regardless of the grounding or non-grounding of the main body frame, noise is generated in the potential of the main body frame. . In fact, if a voltage is measured at a certain distance in the main body frame when the leak occurs, noise corresponding to the leak is generated.

  Further, the control unit 10 detects the noise period of the ground level signal, compares the detected period with the operation time, and determines that a unit having an operation time corresponding to (related to) the period is a noise generation source. presume. The operation time corresponding to the cycle is preferably an operation time suitable for the cycle or an operation time close to the cycle, and preferably includes an operation time such that an integral multiple of the operation time matches or is close to the cycle. . In the latter case, the same result can be obtained by storing not only the operation time but also an operation time of an integer multiple (of course, a finite multiple).

  In the following description, the detection unit 10a is responsible for the detection and the estimation unit 10b is responsible for the comparison and estimation. However, the description may be omitted as the processing of the control unit 10 only. Note that the electronic device 1 preferably includes the notification unit 13. The notification unit 13 will be described later.

  In this way, the control unit 10 can detect whether or not noise due to leakage (abnormal discharge) is generated in the main body of the electronic device 1 by the detection unit 10a, and the estimation unit 10b can detect the generation source. Can also be estimated. That is, in the electronic device 1, when noise is generated in the potential of the main body frame, the noise generation source can be easily estimated (that is, noise generation source candidates can be extracted).

  In particular, in the electronic device 1, noise may occur in the main body frame due to abnormal discharge such as leakage at the time of high-voltage output, and thus the source of such noise can be estimated. Therefore, the effect of the invention becomes more prominent when the plurality of units include a unit that requires a high voltage by an internal transformer or a high voltage output from a high-voltage power supply unit.

  When the plurality of units include a unit that is not a load unit that operates by supplying power from the power supply unit, the unit can also be a noise generation source due to generation of static electricity. Therefore, even when a unit that is not a load unit is a noise generation source, the estimation can be performed.

  Moreover, it is preferable that the control part 10 determines the presence or absence of the said noise by whether the electric potential of the main body frame became more than a reference electric potential. One circuit example of such a configuration will be described with reference to FIGS. 2 is a circuit diagram showing an example of the main part of the electronic device 1, FIG. 3A is a diagram showing the potential of the main body frame and the output potential of the operational amplifier in the electronic device of FIG. 2, and FIG. 3B is a diagram of FIG. It is a figure which shows the electric potential of the main body flame | frame at the time of the noise generation in an electronic device, and the output electric potential of an operational amplifier.

  The main part illustrated in FIG. 2 includes a control board 10c as an example of the control part 10 and a high-voltage power supply board 14 as an example of the power supply part. On the control board 10c, a CPU (Central Processing Unit) 10d that actually performs control is provided. The CPU 10d has functions of a detection unit 10a and an estimation unit 10b. The electronic device 1 in this example includes a diode (semiconductor diode) D and an operational amplifier OP and resistors R1 and R2 before the ground level signal is input to the CPU 10d of the control board 10c.

  The diode D clamps a signal indicating the potential when the potential of the main body frame is equal to or higher than the reference potential (5 V in this example). The operational amplifier OP has a non-inverting input terminal for inputting a signal clamped by the diode D, an inverting input terminal for inputting a signal before clamping, and an output signal as the potential signal (in this example, a ground level signal). Output terminal. If the value obtained by subtracting the potential of the inverting input terminal from the potential of the non-inverting input terminal is a positive value, the output signal output as the ground level signal sticks to the voltage value of the positive power supply. The signal sticks to the negative power supply (0V). The output signal is input to a counter (counter port) 10e provided in the CPU 10d. Thus, the operational amplifier OP functions as a comparator.

  The resistor R2 has one end connected to the frame and the other end connected to the resistor R1. A non-inverting input terminal is connected between the resistors R1 and R2. The anode side of the diode D is frame-connected, and the cathode side is connected between the reference voltage and the resistor R1. The voltage value of the positive power source described above is determined by the reference potential and the voltage dividing ratio of the resistors R1 and R2, and an example in which this value is 2V will be described below. In the following, an example in which the voltage value of the negative power supply is 0V is given.

  Further, as described above, both the inverting input terminal and one end of the resistor R2 are frame-connected, but their connection positions are different (here, the side connected to the inverting input terminal is at the ground level). Since the connection positions are different, as described above, when the leak occurs, noise corresponding to the leak may occur.

  The output signal of the operational amplifier OP according to the ground level signal will be described with reference to FIGS. 3A and 3B. As illustrated in FIG. 3A, when there is no noise due to leakage or the like in the ground level signal of the main body frame, the output signal of the operational amplifier OP always remains 2V (High).

  As illustrated in FIG. 3B, when there is a noise 15 of 2 V or more due to leakage or the like in the ground level signal of the main body frame, the output signal of the operational amplifier OP becomes 0 V (part indicated by reference numeral 16) in synchronization with the noise. As described above, when noise is generated, the output of the operational amplifier OP is inverted at the generation timing of the noise, and a portion where the voltage drops to 0V occurs. And noise due to leakage or the like becomes periodic (referred to as period T) if the operation of the source is periodic. Therefore, the counter 10e measures this period T in cooperation with a timer (not shown), and the CPU 10d estimates the noise generation source with reference to the time information 11a stored in advance based on the measurement result.

  The presence or absence of noise is determined by mounting the diode D and the operational amplifier OP as in the example of FIG. Thus, not only the period T necessary for estimating the noise generation source can be easily determined, but also the CPU 10d can be prevented from being damaged by noise due to leakage (abnormal discharge). 2 shows an example in which the operational amplifier OP and the like are provided on the high-voltage power supply board 14, but the present invention is not limited to this. For example, the operational amplifier OP, the diode D, and the resistors R1 and R2 are connected to the control board 10c side. May be installed.

  Next, an example of the time information 11a will be described with reference to FIG. The time information 11a illustrated in FIG. 4 is information in which the operation time is associated (associated) with each unit (unit 12a, 12b, 12c, etc.) provided in the electronic device 1. In the time information 11a, the operation times T1 to Tn are associated with the n units U1 to Un, respectively.

  Next, an example of noise generation source estimation processing based on the time information 11a will be described with reference to the flowchart of FIG. The counter 10e of the CPU 10d can grasp whether or not noise due to leakage has occurred by inputting and monitoring the ground level signal of the main body frame. When noise due to leakage occurs, the counter 10e observes the occurrence (step S1).

  The counter 10e determines whether or not the noise has a period (step S2). If NO, the process returns to step S1. In step S2, when the counter 10e observes the second noise, the interval is measured, compared with the interval from the second to the third noise observation, and when both intervals coincide, it is determined that there is a period. What is necessary is just to pass the space | interval as the period T to the main body side of CPU10d.

  If YES in step S2, the CPU 10d refers to the time information 11a, compares the measured period T with the operation times T1 to Tn included in the time information 11a, and matches the period T (allows some error). It may be determined whether or not there is an operating time (step S3). If NO in step S3, the process returns to step S1. In step S3, it is also determined whether or not there is an operating time that matches 1 / integer of the period T, and YES may be set if any of them exists.

  In the case of YES in step S3, for example, if the operation time Tm matches the cycle T, the CPU 10d estimates the unit Tm associated with the operation time Tm as a noise source, and names the unit Tm on the operation panel. (Step S4). The user of the electronic device 1 or a service person thereof can narrow down units that are considered to be grounded poorly based on the displayed information, and can shorten the work time for repair and maintenance.

  Further, when determining the coincidence with the period T, a unit associated with the operation time closest to the period T among the operation times T1 to Tn may be estimated as a noise generation source. In addition, when it does not apply to any operation time, it may be other factors, such as a lightning strike, for example. Therefore, it may be estimated that noise is generated due to other factors (such as a lightning strike), and in addition, it may be notified. In addition, since a problem caused by noise occurs when the frequency of occurrence of noise is high, notification may be made only when the number of times per unit time is greater than a predetermined number.

  The display in step S4 is performed by the notification unit 13 described above. The alerting | reporting part 13 is a site | part which alert | reports the information which shows the noise generation source estimated by the control part 10, and is comprised by a display part and / or an audio | voice output part. When the electronic device 1 has an operation panel that accepts a user operation, as shown in step S4, the operation panel is used as the notification unit 13, and for example, an estimated unit name (that is, a leak location) is displayed on the operation panel. What should I do?

  By such estimation (and notification), the service person can grasp in advance the unit that seems to be a cause of failure, prepare necessary parts based on the information, and immediately perform the restoration work of the electronic device 1 It becomes possible to take. Therefore, not only can the time required for the work be shortened and the cost can be reduced, but also the labor cost of the service person can be reduced and the stop time of the electronic device 1 can be shortened.

  Moreover, in the electronic device 1, the alerting | reporting part 13 is not an essential structure. For example, the electronic device 1 may be configured such that the noise generation log is stored in the storage unit 11 or the like without providing the notification unit 13 and can be read from the outside later. Such log storage and reading can be used together with notification by the notification unit 13.

  Hereinafter, an example of the electronic apparatus 1 will be described with reference to FIG. FIG. 6 is a cross-sectional view illustrating a configuration example of an image forming apparatus as an example of the electronic apparatus 1. The image forming apparatus applicable to the present invention is not limited to the illustrated multifunction machine, and may be, for example, an image forming apparatus for single color printing, a copying machine or a single function printer apparatus, It may be a facsimile machine or the like. Of course, the present invention is not limited to the image forming apparatus, and can be applied to other types of electronic devices as long as the power supply unit and the frame of the main body are provided.

  An image forming apparatus 100 forms an image on a recording sheet by an electrophotographic method based on image data transmitted from the outside or read by a scanner (image reading apparatus). The apparatus main body 101 and an automatic document processing apparatus 102 It is comprised by.

  The apparatus main body 101 includes an exposure unit 81, a developing device 82, a photosensitive drum 83, a cleaner unit 84, a charger 85, an intermediate transfer belt unit 86, a fixing unit 87, a paper feed cassette 91a, a paper discharge tray 94, and the like. Here, the developing device 82 corresponds to an example of a developing device according to the present invention. Although not shown, the apparatus main body 101 includes the control unit 10 and the storage unit 11 shown in FIG.

  A document placing table 96 made of transparent glass is provided on the upper portion of the apparatus main body 101, and an automatic document processing device 102 that automatically conveys a document to the document placing table 96 is attached on the upper side. A conveyance roller is provided in this conveyance path. The automatic document processing apparatus 102 is configured to be rotatable in the direction of arrow M, and the document can be placed manually by opening the document table 96.

  The apparatus main body 101 has an image reading device 95 housed in a housing. The image reading device 95 is a reduction optical system image reading device including a light source unit 95a holding a light source and a first mirror, a mirror unit 95b holding a second and a third mirror, and a lens and a CCD 95c. . In addition, the apparatus main body 101 is provided with an operation panel (not shown) so that a user can input an operation. This operation panel can be used as the notification unit 13 in FIG. Further, the apparatus main body 101 includes means for inputting image data from an externally connected apparatus, or means for reading image data from a portable recording medium (both not shown).

  The image data handled in the image forming apparatus 100 corresponds to, for example, four color images of black (K), cyan (C), magenta (M), and yellow (Y). Accordingly, four each of the developing device 82, the photosensitive drum (image carrier) 83, the cleaner unit 84, and the charger 85 are provided so as to form four types of latent images corresponding to the respective colors. An image station is configured. Each color developing device 82 is connected to each color toner bottle 90 through a path (not shown) so that each color toner is supplied.

  The exposure unit 81 is configured as a laser scanning unit (LSU) provided with a laser emitting portion, a reflection mirror, and the like. The exposure unit 81 includes a polygon mirror that scans the laser beam and optical elements such as a lens and a mirror for guiding the laser light reflected by the polygon mirror to the photosensitive drum 83. In addition, as the exposure unit 81, a method using a writing head in which light emitting elements are arranged in an array can be employed.

  The exposure unit 81 has a function of forming an electrostatic latent image corresponding to the image data on the surface thereof by exposing the charged photosensitive drum 83 according to the input image data. The developing device 82 visualizes the electrostatic latent images formed on the respective photosensitive drums 83 with toners of four colors (Y, M, C, K). The cleaner unit 84 removes and collects toner remaining on the surface of the photosensitive drum 83 after development and image transfer. The charger 85 is a charging means for uniformly charging the surface of the photosensitive drum 83 to a predetermined potential. In addition to a charger type as shown in FIG. 6, a contact type roller type or brush type charger is used. Sometimes used.

  The intermediate transfer belt unit 86 disposed above the photosensitive drum 83 includes an intermediate transfer belt 86a, an intermediate transfer belt driving roller 86b, an intermediate transfer belt driven roller 86c, an intermediate transfer roller 86d, and an intermediate transfer belt cleaning unit 86e. I have. Four intermediate transfer rollers 86d are provided corresponding to the respective colors Y, M, C, and K. The intermediate transfer belt drive roller 86b, the intermediate transfer belt driven roller 86c, and the intermediate transfer roller 86d are driven to rotate by stretching the intermediate transfer belt 86a. Each intermediate transfer roller 86d gives a transfer bias for transferring the toner image on the photosensitive drum 83 onto the intermediate transfer belt 86a.

  The intermediate transfer belt 86a is provided so as to contact each photosensitive drum 83. Then, the color toner images (multicolor toner images) are formed on the intermediate transfer belt 86a by sequentially superimposing and transferring the respective color toner images formed on the photosensitive drum 83 onto the intermediate transfer belt 86a. The intermediate transfer belt 86a is formed in an endless shape using, for example, a film having a thickness of about 100 μm to 150 μm.

  The transfer of the toner image from the photosensitive drum 83 to the intermediate transfer belt 86a is performed by an intermediate transfer roller 86d that is in contact with the back side of the intermediate transfer belt 86a. A high voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 86d in order to transfer the toner image. The intermediate transfer roller 86d is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). With this conductive elastic material, a high voltage can be uniformly applied to the intermediate transfer belt 86a. In this configuration example, a roller shape is used as the transfer electrode, but a brush or the like can also be used.

  As described above, the electrostatic images visualized on the respective photosensitive drums 83 according to the respective hues are stacked on the intermediate transfer belt 86a. The electrostatic images stacked in this manner are transferred to a transfer roller (secondary transfer counter roller) which is a secondary transfer mechanism unit disposed at a contact position between a sheet described later and the intermediate transfer belt 86a by the rotation of the intermediate transfer belt 86a. 88 is transferred to the recording paper. The secondary transfer mechanism is not limited to a transfer roller, and a corona charger or a transfer belt can also be used.

  At this time, the intermediate transfer belt 86a and the transfer roller 88 are pressed against each other at a predetermined nip, and a voltage for transferring the toner onto the sheet is applied to the transfer roller 88 (the polarity opposite to the toner charging polarity (-)). (+) High voltage). Further, in order to obtain the above nip constantly, the transfer roller 88 uses either the transfer roller 88 or the intermediate transfer belt drive roller 86b as a hard material (metal or the like) and the other as a soft material such as an elastic roller (elastic). Rubber roller, foaming resin roller, etc.).

  Further, in order to facilitate the separation of the sheet from the intermediate transfer belt 86a after the transfer, a potential separation for applying an AC discharge containing a charge opposite to the transfer or a curvature separation for bending and separating the transferred sheet is performed. There is.

  Further, as described above, the toner attached to the intermediate transfer belt 86a by contacting the photosensitive drum 83 or the toner remaining on the intermediate transfer belt 86a without being transferred to the recording paper by the transfer roller 88 is used in the next step. Therefore, the toner is mixed and removed by the intermediate transfer belt cleaning unit 86e. The intermediate transfer belt cleaning unit 86e is provided with a cleaning blade as a cleaning member that comes into contact with the intermediate transfer belt 86a, for example, and the intermediate transfer belt 86a in contact with the cleaning blade is supported from the back side by an intermediate transfer belt driven roller 86c. ing.

  The paper feed cassette 91 a is a tray for storing recording paper (sheets) used for image formation, and is provided below the exposure unit 81 of the apparatus main body 101. In addition, recording paper used for image formation can be placed in the manual paper feed cassette 91b. A paper discharge tray 94 provided above the apparatus main body 101 is a tray for collecting printed recording sheets face down.

  Further, the apparatus main body 101 has a substantially vertical sheet conveyance path S1 for feeding the recording sheets of the sheet feeding cassette 91a and the manual sheet feeding cassette 91b to the sheet discharge tray 94 via the transfer roller 88 and the fixing unit 87. Is provided. In the vicinity of the paper transport path S1 from the paper feed cassette 91a or the manual paper feed cassette 91b to the paper discharge tray 94, pickup rollers 92a and 92b, a plurality of transport rollers 93a to 93d, a registration roller 89, a transfer roller 88, and a fixing unit. 87 etc. are arranged.

  The transport rollers 93a to 93d are small rollers for promoting and assisting the transport of the recording paper, and a plurality of the transport rollers 93a to 93d are provided along the paper transport path S1. The pickup roller 92a is provided in the vicinity of the end of the paper feed cassette 91a, picks up recording paper one by one from the paper feed cassette 91a, and supplies it to the paper transport path S1. Similarly, the pickup roller 92b is provided near the end of the manual paper feed cassette 91b, picks up recording paper one by one from the manual paper feed cassette 91b, and supplies it to the paper transport path S1.

  The registration roller 89 temporarily holds the recording paper that is being transported through the paper transport path S1. The recording paper is transported to the transfer roller 88 at the timing when the leading edge of the toner image on the photosensitive drum 83 is aligned with the leading edge of the recording paper.

  The fixing unit 87 includes a heat roller 87a and a pressure roller 87b. The heat roller 87a and the pressure roller 87b rotate with the recording paper interposed therebetween. The heat roller 87a is controlled to reach a predetermined fixing temperature based on a signal from a temperature detector (not shown), and is transferred onto the recording paper by thermocompression bonding of the toner to the recording paper together with the pressure roller 87b. The resulting multicolor toner image is melted, mixed, and pressed to be thermally fixed to the recording paper. In addition, an external heating belt 87c for heating the heat roller 87a from the outside is provided.

  Next, the recording paper conveyance path will be described more specifically. As described above, the image forming apparatus 100 is provided with the paper feed cassette 91a for storing recording paper and the manual paper feed cassette 91b in advance. Pickup rollers 92a and 92b are arranged to feed recording paper from these paper feeding cassettes 91a and 91b, respectively, and guide the recording paper one by one to the paper transport path S1.

  The recording paper conveyed from each of the paper feeding cassettes 91a and 91b is conveyed to the registration roller 89 by the conveying roller 93a in the paper conveying path S1, and the timing for aligning the leading edge of the recording paper and the leading edge of the image information on the intermediate transfer belt 86a. Is transferred to the transfer roller 88, and image information is written on the recording paper. Thereafter, the recording paper passes through the fixing unit 87, whereby the unfixed toner on the recording paper is melted and fixed by heat, and is then discharged onto the paper discharge tray 94 via the transport roller 93b disposed thereafter.

  The above-mentioned transport path is for a single-sided printing request for recording paper. On the other hand, when a double-sided printing request is made, the single-sided printing is completed and the recording paper after passing through the fixing unit 87 as described above. When the end is gripped by the final transport roller 93b, the transport roller 93b rotates in reverse to guide the recording paper to the transport path S2 in which the transport rollers 93c and 93d are arranged. The conveyance path S2 joins the conveyance path S1, and the recording paper is conveyed from the registration roller 89 to the transfer roller 88. At this time, since the front and back sides of the recording paper are reversed at the stage of joining from the conveyance path S2 to S1, the transfer roller 88 performs printing on the back side of the recording paper. Then, the recording paper printed on the back surface is fixed by the fixing unit 87 and discharged to the paper discharge tray 94.

  In the above-described image forming apparatus 100, as a unit for storing the operation time, leakage (abnormal discharge) is likely to occur due to the state of a load (contact failure, etc.) connected to the inside (that is, the source of noise generation). It is preferable to include a unit with a high voltage output. For example, a photosensitive drum 83 that is a unit related to development and transfer, an intermediate transfer roller 86d that is a primary transfer roller, an intermediate transfer belt drive roller 86b that is a secondary transfer roller, a transfer roller 88 that is a secondary transfer counter roller, and the like. And various units.

  Each unit is a rotating unit, and the operation time required for one round may be stored as the operation time. By storing the operation time in this way, if the operation time corresponds to the noise period T, it can be estimated that the unit corresponding to the operation time is the noise generation source. Note that in an example in which the operation time is compared with an integral multiple of the operation time when compared with the period T, it is basically assumed that the unit is a unit that is continuously operated (rotated or the like). Such a comparison makes it possible to estimate the noise generation source even when noise is generated every five rotations, for example.

  Other units include, for example, a recording paper conveyance path (conveyance path including rollers 89, 93b, 93c, and 93d) and a manuscript paper conveyance path (conveyance path in the automatic document processing apparatus 102). It is done. In this case, if the operation time (the time from the start of conveyance to the end of conveyance) is stored for each sheet of recording paper and original paper, the paper conveyance path can be a noise source as well. Estimation is possible.

(Second Embodiment)
A second embodiment according to the present invention will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of time information stored in the storage unit in the image forming apparatus of FIG. In this embodiment, differences from the first embodiment will be mainly described, and description of other points will be basically omitted, but various applications such as notification described in the first embodiment will be described. Examples can be applied as well.

  The present embodiment is characterized in that the operation time stored in the storage unit 11 is different from that of the first embodiment. In the storage unit 11 in the present embodiment, a plurality of unit operation times are stored according to the operation content of the electronic device 1. Here, the number of operation times stored for each unit may be different, and operation contents having the same operation time may be stored as overlapping values. For example, some units have a fixed operation time regardless of the operation content. For such units, one operation time is stored, or a plurality of duplicate values are stored. Also good.

  In the example of the image forming apparatus 100 in FIG. 6, the operation contents include the operation speed (process speed), the size of the recording paper, the type of recording paper (plain paper / thick paper, etc.), and the fineness (image quality) of the image to be printed. Can be adopted. As the time information stored in the storage unit 11, for example, the time information 11b illustrated in FIG. In the time information 11b, the photosensitive drum (photosensitive drum 83), the primary transfer roller (intermediate transfer roller 86d), the secondary transfer roller (intermediate transfer belt drive roller 86b), and the secondary transfer counter roller (transfer roller 88). , Operating times T11, T21, T31, T41 at the process speed A and operating times T12, T22, T32, T42 at the process speed B are included. Here, the process speed A and the process speed B represent, for example, the speed when printing on plain paper and the speed when printing on thick paper, respectively.

  The operation time T11 to T42 of the photosensitive drum or the like is a time required for an operation that makes one rotation by rotation (one rotation operation), and the reciprocal value of the rotation speed (number of rotations), that is, the distance of one rotation is the peripheral speed. The value divided by. Depending on the operation content as described above, the distance of the one round does not change, but the rotation speed and the peripheral speed may change. It is set as the value converted to.

  As described above, since a plurality of unit operation times are stored for the unit, the control unit 10 in the image forming apparatus 100 searches for a unit that matches the noise cycle T from a large number of operation times. Therefore, it is possible to estimate the noise source more accurately. Also in the present embodiment, a paper transport path for recording paper or original paper can be applied as another unit. In any case, for example, the operation time (time from the start of conveyance to the end of conveyance) necessary for conveyance of one sheet may be stored for the process speeds A and B. For example, when a noise period T that matches the operation time of the recording paper conveyance path is detected, it can be estimated that there is a noise source in the recording paper conveyance path.

  The above is based on the premise that a search is performed regardless of the operation content currently being executed. However, it is preferable that the control unit 10 estimates the noise generation source by comparing the noise period T with the operation time corresponding to the operation content being executed. As a result, it is possible to estimate a unit having an operation time corresponding to the period T as a noise generation source after narrowing down to an operation time corresponding to the operation content that is actually being executed, and more accurate estimation is possible. It becomes.

  For example, even when the operation time T21 at the process speed A and the operation time T42 at the process speed B in the time information 11b are the same or close values, and the cycle T is also the same or close value, the execution is performed. It is possible to eliminate erroneous estimations by focusing on the operation content. More specifically, if processing at the process speed B is being performed when noise is generated, the secondary transfer counter roller corresponding to the operation time T42 can be estimated as the noise generation source.

  The process speed basically varies depending on the performance of the image forming apparatus 100, but may vary depending on the type of recording paper (plain paper / thick paper, etc.) as described above, and may also vary depending on the image quality and the recording paper size. is there. Therefore, when the time information 11b is stored, the operation time of the unit may be related to one or more of process speed, recording paper type, image quality, and recording paper size. This makes it easy to refer to the operation time for the operation content being executed.

(Third embodiment)
A third embodiment according to the present invention will be described mainly with reference to FIGS. 6 and 8A to 9B. 8A and 8B are diagrams for explaining the paper conveyance path in the image forming apparatus as the electronic apparatus according to the present embodiment. FIG. 8A schematically shows the paper conveyance path in the image forming apparatus in FIG. FIG. 8B is a diagram schematically showing another example of the paper transport path. 9A and 9B are diagrams illustrating examples of time information stored in the storage unit in the image forming apparatus as the electronic apparatus according to the present embodiment. In the present embodiment, differences from the second embodiment will be mainly described, and description of other points will be basically omitted. However, notifications and the like described in the first and second embodiments will be omitted. Various applications can be applied as well.

  As illustrated in FIG. 6, the image forming apparatus 100 according to the present embodiment includes a paper transport path having a plurality of transport rollers (rollers 89, 93 b, 93 c, 93 d, and the like) and a predetermined position in the paper transport path. A sensor Sa for detecting the paper being conveyed is provided. Further, the storage unit 11 in the present embodiment stores in advance the time required from the time when the sheet is detected by the sensor Sa until it reaches each transport roller or (/ and) passes.

  Then, the control unit 10 according to the present embodiment detects (calculates) a time interval (a generation time and a generation timing from the detection time) that is required from when the paper is detected by the sensor Sa until noise of the ground level signal is generated. ) Of course, the detected time point is the time point before the occurrence of noise and closest to the time of noise generation. Further, the control unit 10 compares the detected time interval with the required time, and estimates that the conveyance roller having the required time that matches (or is the same as or close to) the time interval is a noise generation source.

  The reason why the required time is defined as the time required from the time when the sheet is detected by the sensor Sa to the time when the sheet reaches each transport roller or (and / or) passes through is as follows. That is, when the shaft of the transport roller or the like is not correctly frame-connected (in this example, shorted to the ground) and its potential is unstable, the electrostatic charge on the paper is abnormally discharged to the shaft. However, such abnormal discharge often occurs particularly when the paper starts to contact the transport roller or when the paper leaves the transport roller (when the contact with the transport roller ends). .

  Further, it is preferable that the predetermined position is a position upstream of the most upstream conveying roller in the sheet conveying path. When a conveyance path having rollers 89, 93b, 93c, and 93d is defined as the sheet conveyance path, the position of the sensor Sa corresponds to the upstream position as shown in the development of the sheet conveyance path in FIG. 8A. The required times to be stored as time information in the storage unit 11 are t1a, t2a, t3a, and t4a. Although the distance from the sensor Sa to each roller is a fixed value, the required time varies depending on conditions such as the process speed of the image forming apparatus 100, and the time period converted into a time period in consideration of these conditions is t1a, t2a, t3a, and t4a.

  Thereby, the control part 10 can estimate the conveyance roller which has the required time according to the said time interval as a noise generation source. In addition, the abnormal discharge, which is a cause of noise, is generated every time a sheet of paper is transported, not every single sheet. Often to do. In the present embodiment, since the required time and the time interval are compared at the generation timing, the noise generation source can be estimated without any problem even if such noise is generated every time a plurality of sheets are conveyed.

  In addition, as a conveyance roller which memorize | stores a required time, you may also include the conveyance roller 93a, the pickup roller 92a, or the pickup roller 92b, for example, In that case, the definition of said predetermined position and required time is changed so that it may mention later. Thus, the conveyance roller 93a and the rollers 92a or 92b can be detected as noise generation sources. In addition, if the intermediate transfer belt drive roller 86b (transfer roller 88 having the same required time) is stored as one of the transport rollers in the transport path, the required time is stored, and the period T in the first and second embodiments is stored. It can be estimated that the noise generation source is the intermediate transfer belt driving roller 86b or the transfer roller 88 not only from the above viewpoint but also from the viewpoint of the generation timing.

  It supplements about the said predetermined position. An arbitrary position in the sheet conveyance path may be set as the predetermined position. Thereby, a sensor used for other purposes (for example, a paper detection sensor used when picking up recording paper) can be used. As an example, a description will be given of a case where noise is generated from the roller 89 when a sensor is provided between the roller 89 and the roller 93b. Even in this case, the required time calculated in reverse may be stored as the required time for the roller 89. The required time calculated in reverse refers to the time required from the time when the paper reaches each conveyance roller or the time when each paper passes through each conveyance roller until the paper is detected by the sensor. When the transport roller is a noise generation source, noise is generated every time the paper is transported. Therefore, considering the processing one sheet before when the noise is generated, the time required for the reverse calculation as described above (the occurrence of noise) The noise generation source can be estimated by comparing the time interval when the previous sheet starts to contact or passes).

  In addition, since the conveyance of the sheet usually differs depending on the process speed (depending on the type and image quality of the recording sheet) and the recording sheet size, a plurality of times required for the conveyance roller are stored according to the operation content of the image forming apparatus 100. It is preferable. For example, a plurality of types of time information stored in the storage unit 11 may be stored depending on a combination of a difference in process speed and a difference in paper size, as in the time information 11c in FIG. 9A. The time information 11c includes a total of four types of required time for each of the process speeds A / B and A4 / B4 sizes for one transport roller. For example, the required time t1a, t1b, t1c, t1d is stored.

  In the first and second embodiments, since the paper conveyance path is estimated as one unit, the noise is generated in the paper conveyance path even when the conveyance roller in the paper conveyance path is a noise generation source. However, in this embodiment, since the conveyance roller that performs the operation in accordance with the noise generation timing is detected instead of the noise period, the paper conveyance path is used as the noise generation source. Can be specified.

  Further, a sensor Sb illustrated by a dotted line may be provided instead of the sensor Sa. Note that the sensors Sa and Sb are the same sensor, and only their arrangement is different. In this case, as shown in the development view of the sheet conveyance path in FIG. 8B, the position of the sensor Sb corresponds to the upstream position. When one required time is stored for one transport roller, the required times are t1a, t2a, t3a, t4a, t5a, and t6a. Here, the required time t1a and the required time t5a correspond to the same conveying roller 89, but the former is the time when the paper first passes and the latter is the time when the paper passes after the paper is reversed. .

  Further, when the sensor Sb is provided and a total of four types of required times are included for each of the process speeds A / B and A4 / B4 sizes for one transport roller, the time information is as time information 11c in FIG. 9B. . The time information 11d includes, for example, the required times t1a, t5a, t1b, t5b, t1c, t5c, t1d, and t5d for the transport roller 89.

  Also in the present embodiment, it is preferable that the control unit 10 estimates the noise generation source by comparing the time interval with the required time corresponding to the operation content being executed. Compared to the case where the comparison is performed regardless of the operation content currently being executed, the search target can be narrowed down, so that the noise source can be estimated more accurately.

  Although not particularly described above, the description has been made on the assumption that the sheets are conveyed one by one to the sheet conveying path. Therefore, even if abnormal discharge, which is a cause of noise, has the property that static electricity that accumulates during transport of paper reaches a limit each time a number of sheets are transported, the time from detection by the sensor to the occurrence of noise If we looked at the interval, we could estimate the noise-generating transport roller.

  However, the image forming apparatus 100 may perform processing in which a plurality of sheets (N sheets) are being simultaneously conveyed on the sheet conveyance path. When the number of sheets simultaneously conveyed is N, it is necessary to estimate which of the N sheets existing in the sheet conveyance path (that is, which conveyance roller) caused the abnormal discharge due to noise. . Therefore, the time interval from the sensor Sa to the noise detection is not only the time interval based on the detection time at the sensor Sa at the time closest to the noise detection, but also the time point detected by the sensor Sa N-1 times before. It is also necessary to consider N time intervals based on the detection points of the sensor Sa in total N times. In addition, although the case where the sensor Sa is employed will be described, the sensor Sb can be applied in the same way.

  The case where N = 3 will be described as an example. In this case, even when noise is detected, the first sheet (first sheet) in the sheet conveyance path (the sheet closest to the sheet conveyance path exit), the second sheet, the third sheet (most sheet conveyance) Paper close to the road entrance). In order to estimate (specify) the noise generation source conveyance roller by comparison with the required time, noise is generated when the number of sheets out of three is at the position of the conveyance roller as the noise generation source. It is necessary to verify whether it occurred. Therefore, it is necessary to obtain the time interval for comparison for each of the three sheets. That is, the first time interval from the time when the first (first) sheet is detected by the sensor Sa until the noise is generated, and the noise is detected from the time when the second sheet is detected by the sensor Sa. A total of three time intervals, the second time interval required until the occurrence of the noise and the third time interval required until the noise is generated after the third sheet is detected by the sensor Sa, are obtained. It is necessary to keep.

  Then, these three time intervals are compared with the required time stored in the storage unit 11, and if any one of the first to third time intervals matches any one of the required times, It is possible to estimate the noise generation source conveying roller (and the number of the sheet at that time).

  However, the control unit 10 may not be able to determine a single noise generation source depending on the arrangement relationship of the conveyance rollers in the sheet conveyance path (the relationship of the required time from the sensor Sa). For example, the second time interval from detection of the second sheet of the three sheets to noise generation matches one of the required times (for example, t3a corresponding to the roller 93c), and noise from the detection of the third sheet is detected. It is also possible that the third time interval until the occurrence and the other one of the required times (for example, t1a corresponding to the roller 89) coincide. In such a case, all the matched conveyance rollers (in this example, the roller 93c and the roller 89) are regarded as noise generation source candidates, and may be used as an estimation result as they are.

  Further, when N sheets are conveyed at the same time, the control unit 10 determines how many sheets the detection by the sensor Sa goes back (that is, how many sheets are simultaneously conveyed in the sheet conveyance path, and the value of N). ) Must be decided. In a simpler example, the maximum number of sheets simultaneously conveyed in the image forming apparatus 100 may be set to N. However, it can be said that it is preferable for narrowing down to determine the value of N according to the operation content being executed. In particular, since the value of N is determined according to the process speed, the paper size, and the like, it is preferable to determine according to them.

  Also in this embodiment, not only the recording paper conveyance path described above but also the paper conveyance path for original paper can be applied as the paper conveyance path. In this case, a document detection sensor or the like can be used as the sensor. For these paper transport paths, it is only necessary to estimate the noise generation source independently. For this reason, a reference sensor is provided for each paper transport path, and the time required for each transport roller is set for each paper transport path. Just remember. In addition, when scanning and printing are not performed in parallel, the search target can be narrowed down according to the operation currently being executed (scanning or printing).

  As described above, the control unit 10 according to the present embodiment starts from the comparison between the noise period and the operation time of the unit and the detection of the paper among the plurality of units (mainly high-pressure units) and the plurality of transport rollers (shafts thereof). The noise generation source is estimated by comparing the noise generation timing and the required time to the conveyance roller.

  However, the present embodiment is not limited to this, and any configuration can be used as long as the control unit 10 can estimate the noise generation source by comparing it with the noise generation timing among the plurality of transport rollers (shafts thereof). Good. That is, the noise generation source estimation method based on the noise generation timing in this embodiment can be implemented regardless of the adoption / non-adoption of the noise generation source estimation method based on the noise period.

  That is, the control unit 10 according to the present embodiment generates noise in the input of the ground level signal, the detection of the time interval, the comparison between the detected time interval and the required time, and the conveyance roller having the required time that matches the time interval. It is only necessary to be able to execute processing to be estimated as a source, and it is configured so that detection of a noise cycle, comparison between a detected cycle and an operation time, and processing for estimating a unit having an operation time corresponding to the cycle as a noise generation source are not performed. be able to. In this case, the storage unit 11 only needs to store the required time, and the storage of the operation time is not necessary.

  Further, as exemplified in the image forming apparatus 100, the present embodiment can be applied when the electronic apparatus is an image forming apparatus. However, it is possible to estimate the noise generation source in the same way even with electronic devices other than the image forming apparatus. For example, the conveyance target may not be paper. As an example of such an electronic device, a manufacturing apparatus that manufactures a certain product is cited. If this manufacturing apparatus includes a plurality of transport rollers for transporting the product or a material necessary for the manufacture and a sensor for detecting the product or material being transported, The noise generation source can be estimated from among the transport rollers.

(Other)
In the first to third embodiments described above, the example in which the control unit 10 that controls the entire electronic device 1 includes the detection unit 10a and the estimation unit 10b has been described. Instead of this, the detection unit 10a and the estimation unit 10b may be included in the external device attached to the electronic device 1 together with the storage unit 11, for example. This external device may be connected to the electronic device 1 at an arbitrary timing such as maintenance to check noise and estimate the source when noise occurs. In this case, the control unit 10 of the electronic device 1 simply controls the entire electronic device 1, and the detection unit 10a of the external device inputs and monitors the ground level signal. (Period or timing) is detected, and the estimation unit 10b of the external device may estimate the noise generation source.

DESCRIPTION OF SYMBOLS 1 ... Electronic device, 10 ... Control part, 10a ... Detection part, 10b ... Estimation part, 10c ... Control board, 10d ... CPU, 10e ... Counter, 11 ... Memory | storage part, 11a, 11b, 11c, 11d ... Time information, 12a , 12b, 12c ... unit, 13 ... notification unit, 14 ... high voltage power supply board, 100 ... image forming apparatus, D ... diode, OP ... op amp, R1, R2 ... resistor.

Claims (9)

An electronic device comprising a main body frame and a plurality of units electrically connected to the main body frame,
A storage unit that stores the operation time required for the operation of each unit;
A potential signal indicating the potential of the main body frame is input, a period of noise of the potential signal is detected, the detected period is compared with the operation time, and the unit having the operation time corresponding to the period is detected as noise. A control unit that estimates that the source is generated;
An electronic device characterized by comprising:   The electronic apparatus according to claim 1, wherein the control unit determines the presence or absence of the noise based on whether or not a potential of the main body frame is equal to or higher than a reference potential.   The electronic device according to claim 1, wherein a plurality of the operation times of the unit are stored according to the operation content of the electronic device.   The electronic apparatus according to claim 3, wherein the control unit estimates the noise generation source by comparing the cycle with the operation time corresponding to the operation content being executed.   The electronic device according to claim 1, further comprising a notification unit that notifies information indicating the noise generation source estimated by the control unit.   The electronic apparatus according to claim 1, wherein the electronic apparatus is an image forming apparatus. A sheet conveying path having a plurality of conveying rollers, and a sensor for detecting a sheet being conveyed at a predetermined position in the sheet conveying path,
The storage unit stores a required time,
The required time is the time required from the time when the paper is detected by the sensor to the time when the paper reaches each conveyance roller or the time when the paper passes through each conveyance roller, or the time when the paper reaches each conveyance roller or It is the time required from when the paper passes through the conveying roller until the paper is detected by the sensor,
The control unit detects a time interval taken from the time when the sheet is detected by the sensor until noise of the potential signal is generated, compares the detected time interval with the required time, and the time interval The electronic apparatus according to claim 6, wherein the conveyance roller having the required time that meets the requirement is estimated to be the noise generation source.   The electronic device according to claim 7, wherein a plurality of the required times of the transport rollers are stored according to the operation content of the electronic device. The electronic device according to claim 8, wherein the control unit estimates the noise generation source by comparing the time interval with the required time corresponding to the operation content being executed.

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