JP5548584B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer, a multifunction machine, a copying machine, and a facsimile machine that detects a remaining amount of paper.

  Image forming apparatuses such as printers, multifunction machines, copiers, and facsimile machines perform printing using paper. Sheets are stacked and stored on a mounting plate in a sheet feeding unit (which has various names such as “sheet feeding cassette”), and are sent out one by one as printing is performed. For example, the remaining amount of paper in the paper feeding unit may be detected for the purpose of notifying the timing of paper supply. An example of an apparatus for detecting such a remaining amount of paper is described in Patent Document 1.

  Specifically, Patent Document 1 includes a lifter that raises the bottom plate of the paper feed tray to a predetermined position, and uses a value corresponding to the amount of rise to the predetermined position when there is no paper in the paper feed tray as a reference. The value is held, the bottom plate is raised to a predetermined position, the remaining amount of paper in the paper feed tray is detected based on the difference between the value corresponding to the raised amount and the reference value, and the presence or absence of paper is detected. Presence / absence detection means, first detection means for raising the bottom plate to a predetermined position when it is detected that there is no paper, and detecting a value corresponding to the rising amount of the bottom plate at this time; There is described a paper remaining amount detection apparatus including a first correction unit that corrects a reference value based on a value detected by a detection unit. More specifically, it is described that the value corresponding to the amount of increase is the time required to raise the bottom plate or the operation amount of the motor. With this configuration, it is possible to reduce the influence of machine differences, changes in parts over time, and the like, and to detect the remaining amount of paper more accurately (see Patent Document 1: claims 1 to 3, paragraph [0026], etc.).

JP 2007-210663 A

  There are various methods for detecting the remaining amount of paper. For example, the remaining amount of paper may be mechanically detected in conjunction with the height of the loaded paper. In some cases, for example, a plurality of photo sensors are arranged side by side to detect the height of the stacked sheets and detect the remaining amount of sheets.

  When the paper feed roller is positioned above the paper, the placement plate may be raised from the lower limit position by a motor so that the paper feed roller contacts the uppermost paper. The amount of movement of the loading plate from the lower limit position to the upper limit position varies depending on the sheet stacking amount. Therefore, the remaining amount of paper may be detected by using the amount of movement of the placement plate (motor operation time, operation amount, rotation angle) until the upper limit position is reached. The invention described in Patent Document 1 also detects the remaining amount of paper based on the amount of movement of the placement plate.

  However, if the remaining amount of paper is detected using the amount of movement of the mounting plate, it is necessary to move the mounting plate (fully operate the motor) until it reaches the upper limit position from the lower limit position. Therefore, there is a problem that it takes time to detect the remaining amount of paper. There is also a problem that noise is generated by operating the motor. In particular, when the amount of rising of the mounting plate is large (when the remaining amount of paper is small or when a large-capacity paper feeding unit is used), it takes time to detect the remaining amount of paper, and noise increases.

  The problem that requires time to detect the remaining amount of paper and the problem of noise are greatly affected in the power saving mode. In general, when a certain condition is satisfied, the image forming apparatus has a power saving mode (there is various names such as “sleep mode”) in which power supply to a part of the image forming apparatus is stopped. Prepare. For example, the image forming apparatus shifts to the power saving mode if it is not used for a predetermined time since the last job execution. In the power saving mode, the power supply to the paper feeding unit, the motor, and the control element that detects ON / OFF of the motor and the remaining amount of paper may be stopped.

  Here, replenishment of paper to the paper feeding unit, paper replacement, and the like are performed as needed by each user even in the power saving mode. On the other hand, regardless of the mode of the image forming apparatus, for example, a computer that is communicably connected to the image forming apparatus (for example, a user computer that uses the image forming apparatus as a printer or a management computer that manages the image forming apparatus). There is a request to check the remaining amount of paper accurately. In order to be able to accurately check the remaining amount of paper at an arbitrary time, it is necessary to detect the remaining amount of paper even in the power saving mode.

  However, since the power supply is stopped in the power saving mode, in order to detect the remaining amount of paper in the power saving mode, it is necessary to temporarily restart the power supply to the paper feeding unit, the motor, the control element, and the like. However, if the remaining amount of paper is detected by paying attention to the operation time and the operation amount of the motor as in the prior art, it takes time for detection. For this reason, the temporary power supply time in the power saving mode becomes long, and a sufficient energy saving effect cannot be obtained. Further, since the image forming apparatus itself is in a resting state, when the mounting plate is raised, noise is felt greatly.

  Note that the image forming apparatus described in Patent Document 1 detects the remaining amount of paper by paying attention to the operation time and the operation amount of the motor. Therefore, it is impossible to solve the above-described problem of detecting the remaining amount of paper and the problem of noise. Note that Patent Document 1 does not describe the power saving mode.

  The present invention has been made in view of the above-described problems of the prior art, and it is an object of the present invention to reduce the time required for detecting the remaining amount of paper and detect the remaining amount of paper without causing noise.

  According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a placing plate on which a plurality of sheets are stacked; a sheet feeding roller that feeds the sheets; and a sheet loaded on the placing plate that is in contact with the sheet feeding roller. As a drive source for moving the mounting plate, a lift motor whose counter electromotive voltage changes according to a load, a voltage output unit whose output voltage changes according to the counter electromotive voltage of the lift motor, and an output of the voltage output unit A detection processing unit that recognizes the voltage value and detects the remaining amount of the paper placed on the mounting plate based on the output voltage value.

  Where the back electromotive force of the motor changes according to the size (weight) of the load, according to this configuration, the detection processing unit can detect the paper placed on the placement plate based on the output voltage value of the voltage output unit. Detect the remaining amount. Accordingly, since the driving time and the operation amount are measured, it is possible to detect the remaining amount of paper in a short time by shortening the time for which the lift motor is turned on compared to the case where the motor is continuously rotated. Further, noise generated by the operation of the lift motor can be eliminated.

Further, in the invention of 請 Motomeko 1, the image forming apparatus performs power supply, when the shift condition to the power saving mode are complete, at least, a power supply unit for stopping power supply to the detection processing unit, the normal mode A monitoring unit that resumes power supply from the power supply unit to the detection processing unit at least when the transition condition is established, and in the power saving mode, the monitoring unit periodically removes power from the power supply unit The power supply to the detection processing unit is temporarily resumed, and when the power supply is temporarily resumed, the detection processing unit operates the lift motor, turns on the lift motor, and then the voltage. After a predetermined time when the output voltage value of the output unit settles, the output voltage value is recognized to detect the remaining amount of paper, and when the output voltage value is recognized, the lift motor is turned off .

  According to this configuration, in the power saving mode, the monitoring unit periodically resumes power supply from the power supply unit to the detection processing unit, and the detection processing unit temporarily resumes power supply. When the lift motor is operated, the remaining amount of paper is detected. Thereby, the remaining amount of paper can be detected even in the power saving mode. In addition, since the time required for detecting the remaining amount of paper is shorter than when the motor is continuously rotated to measure the driving time and the operation amount, the time for supplying power in the power saving mode can be shortened. Therefore, even if the power supply is temporarily performed in the power saving mode, the problem of noise does not occur, the power consumption can be reduced, and the energy saving effect of the power saving mode is not impaired.

According to a second aspect of the present invention, in the first aspect of the present invention, the invention has a storage unit that stores paper remaining amount detection data that defines the remaining amount of paper with respect to the output voltage value. The remaining amount of paper is detected based on the remaining amount detection data.

  According to this configuration, the detection processing unit detects the remaining amount of paper based on the remaining paper amount detection data. Accordingly, the detection processing unit can easily detect the remaining amount of paper by comparing the output voltage value and the remaining amount detection data.

According to a third aspect of the present invention, in the second aspect of the present invention, the storage unit is the first voltage output value when the lift motor is operated in an empty state where no paper is present on the mounting plate. An output value is stored, and the detection processing unit stores the remaining paper amount detection data to be referred to based on a difference between the output voltage value in the empty state in the remaining paper amount detection data and the first output value. I decided to change it.

  Since there are individual differences in the motor characteristics, according to this configuration, the detection processing unit detects the remaining paper based on the difference between the output voltage value in the empty state in the remaining paper amount detection data and the first output value. Change the amount detection data. As a result, even if the motor characteristics vary from individual to individual, the remaining amount of paper can be detected accurately.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the storage unit is the first voltage output value when the lift motor is operated in an empty state where no paper is present on the mounting plate. An output value and a second output value that is the voltage output value when the lift motor is operated in a full state in which the paper is fully loaded on the mounting plate are stored, and the detection processing unit The remaining sheet amount detection data for checking and referring to the range of the output voltage value corresponding to the empty state and the full state and the range of the first output value and the second output value in the remaining sheet amount detection data. It was decided to change.

  According to this configuration, the detection processing unit checks the output voltage value range corresponding to the empty state and the full state in the remaining paper amount detection data, and the first output value range and the second output value range, and refers to the sheet. Change the remaining amount detection data. Even if there are variations in motor characteristics among individuals, the remaining amount of paper can be accurately detected.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, a series circuit of the lift motor and a resistor is connected between a power source and a ground, and the voltage output unit is configured to input voltage to the lift motor. A differential amplifier circuit for comparing a reference voltage generated by dividing the voltage with a resistor and a voltage between the lift motor and the resistor in the series circuit is included.

  According to this configuration, the voltage output unit differentially compares the reference voltage generated by dividing the input voltage to the lift motor with the resistor and the voltage between the lift motor and the resistor in the series circuit. Circuit. By configuring the circuit in this way, the output of the voltage output unit varies depending on the magnitude of the back electromotive voltage of the motor. Therefore, the remaining amount of paper can be detected based on the magnitude of the back electromotive voltage of the motor. In addition, this invention shows one of the suitable examples of a voltage output part.

According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, the communication unit includes a communication unit for communicating with the outside, and the communication unit externally uses the remaining paper amount detected by the detection processing unit as information. To output.

  According to this configuration, the communication unit outputs the remaining amount of paper detected by the detection processing unit as information to the outside. Thereby, whether or not in the power saving mode, an accurate remaining paper amount can be given to the outside as information.

According to a seventh aspect of the present invention, in the first to sixth aspects of the invention, the lift motor is a DC motor whose back electromotive force varies in proportion to torque.

  According to this configuration, the lift motor is a DC motor in which the back electromotive force changes in proportion to the torque. As a result, the larger the back electromotive voltage, the greater the remaining amount of paper, and the smaller the back electromotive voltage, the less the remaining amount of paper. Based on the magnitude of the back electromotive voltage, the remaining amount of paper can be detected proportionally. Can do. In addition, this invention shows one of the suitable examples of a lift motor.

  As described above, according to the present invention, it is possible to provide an image forming apparatus that detects the remaining amount of paper without generating noise and requiring less time for detecting the remaining amount of paper.

1 is a schematic front sectional view illustrating an example of a multifunction peripheral according to an embodiment. 1 is a block diagram illustrating an example of a hardware configuration of a multifunction machine according to an embodiment. It is a block diagram which shows an example of the control system of the paper feed part which concerns on embodiment. It is a block diagram which shows an example of the electric power supply system which concerns on embodiment. It is a block diagram for demonstrating the interrupt which concerns on embodiment. FIG. 6 is a block diagram illustrating an example of a configuration for detecting a remaining amount of paper according to an embodiment. It is a circuit diagram which shows an example of a structure of the voltage output part which concerns on embodiment. It is a graph which shows an example of the output voltage value of the voltage output part which concerns on embodiment. It is explanatory drawing which shows an example of the paper remaining amount detection data which concerns on embodiment. It is explanatory drawing which shows an example of the paper residual amount display screen which concerns on embodiment. 6 is a flowchart illustrating an example of a flow of detecting a remaining amount of paper in a power saving mode in the multifunction peripheral according to the embodiment. It is explanatory drawing which shows an example of the concept of the correction | amendment by the detected paper remaining amount detection which concerns on embodiment. It is explanatory drawing which shows an example of the setting screen for correction | amendment of the detected paper remaining amount detection which concerns on embodiment. It is explanatory drawing which shows the structural example of the image forming apparatus of other embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the present embodiment, a description will be given by taking the MFP 100 (corresponding to an image forming apparatus) as an example. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

(Schematic configuration of MFP 100)
First, an outline of a multifunction peripheral 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic front cross-sectional view illustrating an example of a multifunction peripheral 100 according to an embodiment of the present invention.

  The multifunction peripheral 100 according to the present embodiment is provided with the document conveying device 2 at the top. The document conveying device 2 conveys the stacked documents one by one to the reading position of the image reading unit 3. Further, the document conveying device 2 is provided with a fulcrum (not shown) on the back side of the paper surface, and is opened upward. For example, a document such as a book can be placed on the placement reading contact glass 32 on the upper surface of the image reading unit 3.

  Next, as indicated by a broken line in FIG. 1, an operation panel 4 that functions as an input unit and displays various types of information is provided in the upper front portion to set printing such as copying. The operation panel 4 includes a plurality of keys such as a power key 42, a power saving key 43, a numeric keypad 44, and a start key 45 in addition to the touch panel type liquid crystal display unit 41.

  The liquid crystal display unit 41 displays information related to printing and displays the status of printing, errors, and the like on the multifunction device 100. In addition, the liquid crystal display unit 41 displays, for example, the paper size used for printing, enlargement / reduction, density setting, etc. Displays function setting keys and buttons. The operation panel 4 recognizes that the user has pressed a key or button displayed on the liquid crystal display unit 41 by detecting the pressed position coordinates using the touch panel. Accordingly, the user can set various functions of the multifunction peripheral 100.

  The power key 42 is a key for instructing ON / OFF of the main power supply of the multifunction peripheral 100. The power saving key 43 is a key for instructing the transition to the power saving mode of the multifunction peripheral 100. The power saving key 43 may be used as a key for instructing a return from the power saving mode to the normal mode. The numeric keypad 44 is configured by combining numeric keys of 0 to 9, *, #, and symbols, and is used when inputting numbers such as printing copy number input and FAX number input. The start key 45 is pressed when an operation start is instructed after the setting is completed by the liquid crystal display unit 41, the numeric keypad unit 44, or the like.

  Further, the MFP 100 main body is provided with an image reading unit 3, a paper feeding unit 1, a conveyance path 5, an image forming unit 6, a fixing unit 6B, and the like. The image reading unit 3 reads a document and generates image data. Further, contact glass (two types of 31 and 32) is provided on the upper surface of the image reading unit 3, and a moving frame (exposure lamp, mirror) that moves in the horizontal direction (left-right direction in FIG. 1) is provided therein. Etc.), an optical system member (all not shown) such as a lens and an image sensor (for example, CCD) is provided. For example, when a document conveyed continuously by the document conveying device 2 is read, a moving frame is fixed below the feed reading contact glass 31, and the reflected light of the document is guided to a lens and an image sensor. Further, when reading a document placed on the placement reading contact glass 32, the moving frame is moved in the horizontal direction, and the reflected light of the document is guided to a lens and an image sensor.

  The image reading unit 3 uses these optical system members to irradiate light on the document, A / D-converts the output value of each pixel of the image sensor that receives the reflected light of the document, and generates image data. The multi-function device 100 can print based on the read image data (copy function).

  In the multifunction peripheral 100 of the present embodiment, the paper feed unit 1 includes a cassette 10 that houses and supplies paper for image formation. The cassette 10 is loaded with a plurality of sheets (for example, about 500 to 1000 sheets) of various sizes (for example, plain paper, copy paper, recycled paper, etc.) and various sizes (for example, A4, A3, B4, B5, letter size, etc.). And accommodate. In addition, a plurality of stages of paper feeding units 1 can be attached below the paper feeding unit 1 to increase the paper storage capacity.

  As shown in FIG. 1, the paper feeding unit 1 has a placement plate 11 for placing paper in the cassette 10, and the uppermost of the papers placed above the placement plate 11. A paper feed roller 12 that contacts the paper is provided. The paper feed roller 12 can move (swing) in the vertical direction. The loading plate 11 has an end on the upstream side in the transport direction as a fulcrum, an end on the downstream side in the paper transport direction as a free end, and the free end moves in the vertical direction. Further, a paper out sensor 13 (for example, a reflective or transmissive optical sensor) for detecting the presence or absence of paper on the mounting plate 11 can be provided below the mounting plate 11.

  In order to raise the mounting plate 11, the paper feed unit 1 is provided with a shaft 14, a push-up member 15, a lift motor 16 (see FIG. 3) and the like. The shaft 14 is provided below each placement plate 11 and extends in a direction perpendicular to the paper transport direction. The shaft 14 is attached with a push-up member 15 that is plate-shaped and contacts the lower surface of the mounting plate 11. The lift motor 16 rotates the shaft 14 and changes the angle of the push-up member 15 to raise the mounting plate 11.

  The cassette 10 can be inserted and removed for paper supply. When the cassette 10 is removed from the multifunction device 100, the push-up member 15 falls down. On the other hand, when the cassette 10 is attached to the multifunction peripheral 100, the lift motor 16 rotates and the placement plate 11 is pushed up. In order to detect whether the cassette 10 is attached or removed (drawn), an insertion / removal detection sensor 17 is provided (for example, an interlock switch that contacts one surface of the cassette 10, Reflective light sensor).

  Further, an upper limit detection sensor 18 is provided (for example, a transmission type optical sensor) in order to detect that the mounting plate 11 (which can also be referred to as the paper feed roller 12) has reached the upper limit position. When the protrusion provided on the paper feed roller 12 gets into the recessed portion of the upper limit detection sensor 18 due to the rise of the paper feed roller 12, the output of the upper limit detection sensor 18 changes (upper limit detection). The lift motor 16 rotates and the mounting plate 11 is pushed up until the upper limit detection sensor 18 detects that the upper limit of the paper feed roller 12 has been reached. Further, when the sheet is consumed by printing and the upper limit detection sensor 18 does not detect that the upper limit of the paper feed roller 12 has been reached, the lift motor 16 rotates and the placement plate 11 is pushed up. As a result, the uppermost sheet and the sheet feeding roller 12 are always in contact with each other.

  Next, the transport path 5 is a path for transporting paper in the apparatus. In the conveyance path 5, a plurality of conveyance roller pairs 51 (in FIG. 1, a total of five pairs 51 a to 51 e are illustrated from the upstream side) that rotate and rotate during sheet conveyance, and the sheet to be conveyed are stored in the image forming unit 6. A registration roller pair 52 or the like is provided that waits in front and sends out the toner image formation timing.

  The image forming unit 6 forms an image (toner image) on a sheet fed from the sheet feeding unit 1 based on the image data, and transfers the toner image onto the conveyed sheet. As the image data, document image data acquired by the image reading unit 3 and transmission image data from the computer 200 (see FIG. 3) connected to the multifunction peripheral 100 are used. The image forming unit 6 includes a photosensitive drum 61 that is rotatably supported in the direction of the arrow shown in FIG. 1, a charging device 62, an exposure device 63, a developing device 64, and a transfer roller disposed around the photosensitive drum 61. 65, a cleaning device 66, and the like.

  The toner image formation and transfer process will be described. A photosensitive drum 61 that is rotationally driven in a predetermined direction substantially at the center of the image forming unit 6 is charged to a predetermined potential by a charging device 62 above the photosensitive drum 61 in FIG. Let The exposure device 63 outputs laser light L based on the image data, and scans and exposes the surface of the photosensitive drum 61 from the right side of the charging device 62 in FIG. 1 to form an electrostatic latent image corresponding to the image data.

  In FIG. 1, the developing device 64 on the right side of the photosensitive drum 61 supplies toner to the electrostatic latent image formed on the photosensitive drum 61 and develops it. The transfer roller 65 below the photosensitive drum 61 is pressed against the photosensitive drum 61 to form a nip. Then, the registration roller pair 52 is timed to cause the sheet to enter the nip. When the nip between the paper and the toner image enters, a predetermined voltage is applied to the transfer roller 65, and the toner image on the photosensitive drum 61 is transferred to the paper. The cleaning device 66 removes the toner remaining on the photosensitive drum 61 after the transfer.

  The fixing unit 6B fixes the toner image transferred to the paper. The fixing unit 6B is mainly composed of a heating roller 67 and a pressure roller 68 containing a heating element. The heating roller 67 and the pressure roller 68 are in pressure contact to form a nip. When the sheet passes through the nip, the toner is melted and heated, and the toner image is fixed on the sheet. The sheet after toner fixing is discharged to a discharge tray 69.

(Hardware configuration of MFP 100)
Next, a hardware configuration of the multifunction peripheral 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram illustrating an example of a hardware configuration of the multifunction peripheral 100 according to the embodiment of the present invention.

  As illustrated in FIG. 2, the multifunction peripheral 100 according to the present embodiment includes a main control unit 7 (control board) configured by combining various elements, circuits, and the like. The image reading unit 3, the operation panel 4, the engine control unit 8, the document conveyance device 2, the monitoring unit 9, and the like are connected to the main control unit 7 so as to be communicable. The main control unit 7 communicates with the image reading unit 3, the operation panel 4, the engine control unit 8, the document conveying device 2, and the monitoring unit 9, controls operations, and obtains information.

  The main control unit 7 includes, for example, a main CPU 71, a storage unit 72, an image processing unit 73, and the like. The main CPU 71 is an arithmetic processing unit of the main control unit 7, and performs processing and control based on data and programs stored in the storage unit 72. The storage unit 72 is configured by combining, for example, a nonvolatile storage device (flash ROM or HDD) and a volatile storage device (for example, RAM). The storage unit 72 stores data and programs required for various controls such as copying and transmission.

  The image processing unit 73 performs image processing on the image data generated by the image reading unit 3 and image data input from the outside. For example, the image processing unit 73 includes an ASIC dedicated to image processing and a memory for image processing. The image data after image processing can be sent to the exposure device 63 for printing (copy function, printer function), can be stored in the HDD of the storage unit 72 (scanner function), or the monitoring unit 9 described later. Via the communication unit 95 to the outside (computer 200, FAX apparatus 300, etc.) (scanner function, FAX function). Note that image processing that can be performed by the image processing unit 73 is diverse, such as enlargement / reduction processing, density change, and the like.

  An engine control unit 8 that controls printing is provided in the multifunction peripheral 100. The engine control unit 8 controls the operations of the above-described document conveying device 2, each paper feeding unit 1, the conveyance path 5, the image forming unit 6, and the fixing unit 6B. The engine control unit 8 includes, for example, an engine CPU 81 and a storage unit 82 as control elements. The engine control unit 8 receives instructions from the main control unit 7 and controls the operations of the paper feeding units 1, the conveyance path 5, the image forming unit 6, and the fixing unit 6B. For example, the engine control unit 8 performs control such as paper feeding, conveyance, toner image formation, and temperature control of the fixing unit 6B. The engine control unit 8 is connected to the monitoring unit 9 so as to be communicable.

  In addition, the monitoring unit 9 is provided as a part that performs power management in the multifunction peripheral 100 and communication with the outside. The monitoring unit 9 controls power supply to each unit in the multifunction peripheral 100. For example, the monitoring unit 9 includes, for example, a controller 91 and a memory 92 that stores data and programs for the monitoring unit 9.

  The power supply unit 90 is connected to, for example, a commercial power supply, and includes a rectifier circuit, a booster circuit, a step-down circuit, and the like, and generates a plurality of types of voltages required for the operation of the multifunction peripheral 100 (for example, for driving various motors). DC24V, DC5V for driving various control units, 3.3V, etc.). And the monitoring part 9 has the switch part 93 for turning ON / OFF the power supply to each part (the main control part 7, the engine control part 8, etc.). The monitoring unit 9 uses the switch unit 93 to open and close the power supply line from the power supply unit 90 to each unit, and controls ON / OFF of the power supply to each unit. The interrupt I / F unit 94 receives an interrupt from an interrupt generation unit that detects that an operation or input has been performed on the multifunction peripheral 100 (details will be described later). When the multifunction device 100 is in the power saving mode, the monitoring unit 9 resumes power supply to the main control unit 7 and each unit using an interrupt as a trigger, and enters the normal mode (details will be described later).

  The communication unit 95 is an interface for communicating with an external computer 200 (for example, a personal computer) or the FAX apparatus 300 through a network, a line, a cable, or the like. Therefore, the communication unit 95 includes various connectors, communication circuits, elements, a controller 91, and the like. The main control unit 7 can receive printing data from the external computer 200 or the FAX apparatus 300 through communication via the communication unit 95 and can transmit image data to the external computer 200 or the FAX apparatus 300. When the communication unit 95 receives data from the outside in the power saving mode, the monitoring unit 9 returns the multifunction peripheral 100 to the normal mode.

(Control system of paper feed unit 1)
Next, an example of the control system of the sheet feeding unit 1 according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram illustrating an example of a control system of the paper feeding unit 1 according to the embodiment of the present invention.

  First, the engine control unit 8 controls a motor and a circuit included in the sheet feeding unit 1 and performs detection based on a sensor. For example, the engine control unit 8 receives the output of the paper size sensor 110 and detects the size of the stored paper. Further, the engine control unit 8 receives the output of the paper out sensor 13 and detects the paper out. The engine control unit 8 receives the output of the upper limit detection sensor 18 and detects that the mounting plate 11 (paper feed roller 12) has been lifted to the upper limit. Further, the engine control unit 8 operates the paper feed motor 121 to rotate the paper feed roller 12 to feed paper. Further, the engine control unit 8 raises the placement plate 11 by the lift motor 16 until the placement plate 11 (paper feed roller 12) reaches the upper limit. The engine control unit 8 receives the output of the voltage output unit 19 and detects the remaining amount of paper.

  The main control unit 7 gives an instruction to perform printing to the engine control unit 8, and the engine control unit 8 controls the operation of the paper feeding unit 1 based on the operation instruction. Further, data indicating the state of the paper feed unit 1 (for example, out of paper, accommodated paper size, remaining amount of paper, etc.) can be transmitted from the engine control unit 8 to the main control unit 7 or the monitoring unit 9. Thereby, the main control unit 7 and the monitoring unit 9 can recognize the status of the paper feeding unit 1 and can notify the status to the outside.

(Outline of power supply system)
Next, an example of the power supply system according to the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram illustrating an example of a power supply system according to the embodiment of the present invention. In addition, the solid line arrow in FIG. 4 has shown an example of the electric power supply path | route.

  As described above, the monitoring unit 9 controls power supply to each unit of various voltages generated by the power supply unit 90. For example, the monitoring unit 9 controls the supply of power to the main control unit 7, the image reading unit 3, the operation panel 4, and the engine control unit 8. When the engine control unit 8 is supplied with electric power, the document conveyance device 2, each paper feeding unit 1, the conveyance path 5, the image forming unit 6, and the fixing unit 6B connected to the engine control unit 8 (via the engine control unit 8). ) Receive power supply. Accordingly, when the power supply to the engine control unit 8 is stopped, the power supply to the paper feeding unit 1 and the like is also stopped. Note that the switch unit 93 may be provided on the power supply unit 90 side, and the power supply unit 90 may perform actual power supply control while the monitoring unit 9 gives an instruction to the switch unit 93.

(Transition between normal mode and power saving mode)
Next, an outline of the transition between the normal mode and the power saving mode in the multifunction peripheral 100 according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 5 is a block diagram for explaining interrupts according to the embodiment of the present invention.

  In the MFP 100 according to the present embodiment, for example, the power supply unit 90 and the monitoring unit 9 normally supply power to all parts such as the main control unit 7, the image reading unit 3, the operation panel 4, and the engine control unit 8. Has a mode. In the normal mode, the power supply unit 90 and the monitoring unit 9 supply power to the engine control unit 8 and keep the sheet feeding unit 1 and the like in a controllable state.

  However, even in a standby state where the multifunction peripheral 100 is not used, in the normal mode, the temperature of the fixing unit 6B is maintained, various control units are driven, and a certain amount of power is consumed. On the other hand, from the viewpoint of energy saving, the power consumption (standby power) in the standby state is preferably small. For this reason, the multifunction peripheral 100 according to the present embodiment has a power saving mode in which power consumption is reduced as compared with the normal mode.

  Therefore, the transition from the normal mode to the power saving mode will be described. The normal mode starts when the MFP 100 is activated by turning on the main power or when the power saving mode is shifted to the normal mode. In the normal mode, when the condition is satisfied, the mode shifts to the power saving mode. The transition condition from the normal mode to the power saving mode can be arbitrarily set. For example, pressing of the power saving key 43 on the operation panel 4 can be set as a condition for shifting to the power saving mode. The main control unit 7 communicates with the operation panel 4 to confirm whether or not the power saving key 43 is pressed, and confirms whether the condition is satisfied.

  Further, for example, the fact that the standby state has continued for a predetermined time can also be set as a transition condition from the normal mode to the power saving mode. The main control unit 7 operates from the predetermined starting point (for example, a plurality of types such as a job end time or a warm-up end time) without any operation or input to the multi-function device 100 (without an interrupt described later). It is confirmed whether a certain period of time (for example, several minutes to several tens of minutes, can be set on the operation panel 4. For example, the main control unit 7 measures time). For example, the main control unit 7 communicates with each unit, or receives the output of the sensor of each unit, places the document on the document conveying device 2, opens / closes the document conveying device 2, inputs an operation to the operation panel 4, and communication The operation of the multifunction peripheral 100 such as input of image data from the outside to the unit 95 and the presence / absence of input are confirmed.

  When the transition condition from the normal mode to the power saving mode is satisfied, a transition instruction is issued from the main control unit 7 to the monitoring unit 9 or the power supply unit 90. In response to this, the monitoring unit 9 and the power supply unit 90 stop supplying power to the main control unit 7 and the engine control unit 8. The multifunction device 100 is in the power saving mode. In the power saving mode, for example, the monitoring unit 9 and an interrupt generation unit that detects an operation or input to the multifunction peripheral 100 by a user and generates an interrupt as a trigger for shifting from the power saving mode to the normal mode. Only power is supplied. For example, the engine control unit 8 stops operating, and no power is supplied to the paper feeding unit 1.

  Next, an example of return (transition) from the power saving mode to the normal mode will be described with reference to FIG. When entering the power saving mode, the monitoring unit 9 confirms whether an interrupt from each interrupt generation unit has been received (whether the interrupt I / F unit 94 has received an interrupt). When there is an interrupt, the monitoring unit 9 shifts the state of the multifunction peripheral 100 from the power saving mode to the normal mode.

  The monitoring unit 9 receives, as an interrupt (trigger), an operation, input, or external data input by the user with respect to the multifunction device 100. If there is an interruption, the monitoring unit 9 and the power supply unit 90 resume the power supply to all the parts such as the main control unit 7 and the engine control unit 8, and return the multifunction peripheral 100 from the power saving mode to the normal mode. .

  Various interrupts will be described with reference to FIG. For example, the interrupt generation unit in the monitoring unit 9 includes a communication unit 95. The communication unit 95 generates an interrupt when receiving printing data (image data or print setting data) from the external computer 200 or receiving FAX data (interrupt A in FIG. 5). The operation panel 4 can also be an interrupt generation unit. When touching the touch panel or pressing any key (for example, the power saving key 43), the operation panel 4 generates an interrupt and inputs it to the monitoring unit 9 (interrupt B in FIG. 5).

  Moreover, as an interruption generation | occurrence | production part, there exists the cover opening / closing detection sensor 53 which detects opening / closing of a cover, for example (refer FIG. 1). The output of the cover open / close detection sensor 53 changes depending on the operation (open / close) state of the housing cover for maintenance, consumable replacement, and paper jam processing. When the cover open / close detection sensor 53 detects opening / closing of the cover, the cover open / close detection sensor 53 generates an interrupt and inputs it to the monitoring unit 9 (interrupt C in FIG. 5).

  Further, as an interrupt generation unit in the document conveying device 2, for example, a document placement detection sensor 22 (see FIG. 1, interrupt D in FIG. 5) for detecting document placement on the document placement tray 21, or a document There is an open / close detection sensor 23 (see FIG. 1, interrupt E in FIG. 5) for detecting the raising and lowering of the conveying device 2. The document placement detection sensor 22 is provided on the document placement tray 21 to detect that a document is placed (see FIG. 1). The document placement detection sensor 22 is, for example, an optical sensor, and the output changes between when the document is placed and when no document is placed. An open / close detection sensor 23 (shown by a broken line in FIG. 1) is provided to detect whether the document feeder 2 is open or closed. For example, the open / close detection sensor 23 may be an interlock type switch in contact with the lower surface of the document conveying device 2 or a reflection type optical sensor as long as the open / close state can be detected. When the document placement detection sensor 22 or the open / close detection sensor 23 detects an operation (document placement or raising / lowering) on the document conveying device 2 for copying or the like, an interrupt is generated and input to the monitoring unit 9.

  In the normal mode, the occurrence of interrupts and the contents thereof may be transmitted from the monitoring unit 9 to the main control unit 7, and outputs from various sensors may be input to the main control unit 7. May be.

  In the example shown in FIG. 5, the communication unit 95, the power saving key 43, the cover open / close detection sensor 53, the document placement detection sensor 22, etc. correspond to the interrupt generation unit, but further, another type of interrupt generation unit is provided. May be. Also, in order to detect the user's operation and input even in the power saving mode, even if the power supply to the main control unit 7 or the engine control unit 8 is stopped due to the shift to the power saving mode, each interrupt generation unit In contrast, power supply continues.

(Overview of remaining amount detection)
Next, an outline of detection of the remaining amount of paper in the multifunction peripheral 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram illustrating an example of a configuration for detecting the remaining amount of paper according to the embodiment of the present invention.

  A motor switch 83 is provided to control ON / OFF of power supply from the power supply unit 90 that generates the voltage for the motor to the lift motor 16. The engine control unit 8 controls (ON / OFF) the lift motor 16 by the motor switch 83. When the motor switch 83 is turned on and the lift motor 16 operates, a counter electromotive voltage is generated in the lift motor 16.

  The lift motor 16 of this embodiment is a DC motor (with a brush), for example. In this DC motor, the back electromotive voltage increases in proportion to the load (torque). That is, the lift motor 16 is a DC motor in which the back electromotive voltage changes in proportion to the torque. The voltage output unit 19 outputs different voltages depending on the magnitude of the back electromotive voltage of the lift motor 16. Based on the output voltage value of the voltage output unit 19, the engine control unit 8 detects the remaining amount of paper.

(Configuration of voltage output unit 19)
Next, an example of the configuration of the voltage output unit 19 according to the embodiment of the present invention will be described with reference to FIG. FIG. 7 is a circuit diagram showing an example of the configuration of the voltage output unit 19 according to the embodiment of the present invention.

  First, a motor switch 83 is provided in the middle of a power supply path from a power source (for example, DC 24 V) to the lift motor 16. As shown in FIG. 7, the motor switch 83 is composed of a p-type transistor. The p-type transistor is connected in parallel with a series circuit composed of a resistor R1 and a resistor R2 and a series circuit composed of a lift motor 16 and a resistor R3.

  The voltage output unit 19 includes a differential amplifier circuit 190 including a plurality of resistors and a buffer 191. The differential amplifier circuit 190 includes a buffer 191, a resistor R4 and a resistor R5 (for feedback) connected to one input end of the buffer 191, and a resistor R6 and a resistor R7 connected to the other input end of the buffer 191. Become.

  As one input to the differential amplifier circuit 190, a voltage between the lift motor 16 and the resistor R3 is input. As the other input to the differential amplifier circuit 190, a voltage between the resistors R1 and R2 (almost a voltage obtained by dividing the power supply voltage by the resistors R1 and R2) is input.

  Here, the voltage (emitter voltage of the transistor) between the motor switch 83 and the lift motor 16 is Vb [V], the back electromotive voltage of the lift motor 16 is Ec [V], and the internal resistance of the lift motor 16 is Ra [Ω]. To do. When the voltage between the resistor R1 and the resistor R2 is V1, V1 = R2 / (R1 + R2) × Vb. On the other hand, when the voltage between the lift motor 16 and the resistor R3 is V2, V2 = R3 / (R3 + Ra) × (Vb−Ec).

  Here, in the differential amplifier circuit 190 of the present embodiment, for example, resistance R4 = resistance R5 = resistance R6 = resistance R7. Then, the differential amplifier circuit 190 (voltage output unit 19) outputs the difference between V1 and V2. In other words, the voltage output unit 19 is a circuit that outputs the difference between V1 and V2 to the engine control unit 8.

Specifically, the output Vout (output voltage value) of the voltage output unit 19 is obtained by the following equation.
Vout = V1-V2
= R2 / (R1 + R2) * Vb-R3 / (R3 + Ra) * (Vb-Ec)
= R2 / (R1 + R2) × Vb−R3 / (R3 + Ra) × Vb + R3 / (R3 + Ra) × Ec
Here, in the voltage output unit 19 of the present embodiment, the resistance R1, the resistance R2, and the resistance R3 are adjusted so as to have the following relationship.
Resistor R1: Internal resistance Ra = Resistor R2: Resistor R3

Then, Vout is as follows.
Vout = R3 / (R3 + Ra) × Ec
= R2 / (R1 + R2) × Ec
When the value of each resistor is treated as a constant, the voltage output unit 19 of the present embodiment outputs a voltage proportional to the counter electromotive voltage Ec of the lift motor 16. The engine control unit 8 converts, for example, an analog voltage output from the voltage output unit 19 into digital data using an A / D conversion port of the engine CPU 81 or an A / D converter provided separately, Recognizes the output voltage value. That is, a series circuit of the lift motor 16 and the resistor (R3) is connected between the power source and the ground, and the voltage output unit 19 is generated by dividing the input voltage to the lift motor 16 by the resistors (R1, R2). A differential amplifier circuit 190 is included for comparing the reference voltage (V1) with the voltage (V2) between the lift motor 16 and the resistor (R3) in the series circuit.

(Output voltage value of voltage output unit 19)
Next, an example of an output change according to the remaining amount of paper of the voltage output unit 19 according to the embodiment of the present invention will be described with reference to FIG. FIG. 8 is a graph showing an example of the output voltage value of the voltage output unit 19 according to the embodiment of the present invention.

  The graph of FIG. 8 is a graph indicated by a broken line when there is little paper (a graph indicated by a solid line), and when there is more paper remaining than when there is a small amount of paper (when the remaining amount of paper is greater than in the graph indicated by a solid line). ) Shows an example of the difference in the output voltage value of the voltage output unit 19. In the graph of FIG. 8, the vertical axis indicates the magnitude of the output voltage value of the voltage output unit 19, and the horizontal axis indicates the time after the lift motor 16 is turned on.

  The more sheets in the sheet feeding unit 1, the heavier the sheet bundle. Therefore, the load on the lift motor 16 (the torque of the lift motor 16) becomes larger when the number of sheets in the sheet feeding unit 1 is larger. The lift motor 16 of the present embodiment is a DC motor, and the back electromotive force increases in proportion to the magnitude of torque to be output.

  For example, assume that the lift motor 16 is turned on at the time T1 in the graph of FIG. Incidentally, T2 is a point where it is turned off. As shown in the graph of FIG. 8, the voltage output unit 19 of the present embodiment has a larger output voltage value (Vout) when the load (torque) of the lift motor 16 is larger than when it is smaller ( Difference between solid arrow section and dashed arrow section). Therefore, the engine control unit 8 recognizes the output voltage value after a predetermined time t1 when the output voltage value of the voltage output unit 19 settles after the lift motor 16 is turned on. Depending on the characteristics of the lift motor 16, for example, the predetermined time t1 may be several hundred milliseconds. Therefore, the engine control unit 8 can detect the remaining amount if the lift motor 16 is turned on only for a time that the lift motor 16 does not rotate or slightly rotates.

(Remaining paper detection)
Next, an example of remaining sheet detection in the multifunction peripheral 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 9 is an explanatory diagram showing an example of the remaining paper amount detection data according to the embodiment of the present invention.

  When the engine control unit 8 recognizes the output voltage value of the voltage output unit 19, the engine control unit 8 detects the remaining amount of paper based on the output voltage value. For example, the engine control unit 8 refers to paper remaining amount detection data as illustrated in FIG. 9 to detect the remaining amount of paper. The remaining sheet detection data is table data in which the level of the remaining sheet is determined in stages with respect to the output voltage value of the voltage output unit 19. The remaining paper amount detection data is stored, for example, in the storage unit 82 of the engine control unit 8, and the engine CPU 81 refers to the remaining paper amount detection data to detect the remaining paper amount.

  Specifically, the remaining paper amount detection data determines the remaining amount of paper stepwise with respect to the range of the output voltage value. In this embodiment, the remaining amount of paper is detected in 10 stages (10 levels). Note that out of paper (paper remaining amount 0%) is detected by the paper out sensor 13. Further, the number of levels (number of levels) of the remaining amount of paper may be reduced (for example, 4 levels or 5 levels), or may be detected at a finer level (for example, 20 levels if 5% increments, 1 100 steps in% increments). Further, the remaining paper amount detection data may be a function for obtaining the remaining paper amount instead of the table data.

  In other words, the image forming apparatus (for example, the multifunction peripheral 100) according to the present invention includes a storage unit 72 that stores paper remaining amount detection data that defines the remaining amount of paper with respect to the output voltage value. The engine control unit 8) detects the remaining amount of paper based on the remaining paper amount detection data.

(Remaining paper display)
Next, an example of the remaining sheet display in the multifunction peripheral 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 10 is an explanatory diagram showing an example of the remaining sheet display screen S1 according to the embodiment of the present invention.

  FIG. 10 is an example of the remaining sheet display screen S1 displayed on the display of the computer 200 that is communicably connected to the multifunction peripheral 100 via the communication unit 95 or the liquid crystal display unit 41 of the operation panel 4, for example. . On the remaining paper amount display screen S1, the remaining paper amount is displayed on a scale along with the paper size and the like. In this sheet remaining amount display screen S1, one scale is set for each level. As shown in FIG. 10, the number of scales is displayed up to ten (FIG. 10 illustrates a substantially full state). For example, if there are one or two scales, the user can determine that the sheet needs to be replenished soon. When the paper is out, the scale is not displayed, and characters such as “out of paper” are displayed instead.

(Remaining paper amount detection in power saving mode)
Next, the detection of the remaining amount of paper in the power saving mode in the MFP 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 11 is a flowchart illustrating an example of the flow of detecting the remaining amount of paper in the power saving mode in the multifunction peripheral 100 according to the embodiment of the present invention.

  First, the background of detecting the remaining amount of paper in the power saving mode will be described. In the power saving mode, power is not supplied to the engine control unit 8, the paper feeding unit 1 that receives power supply from the engine control unit 8, and the image forming unit 6. In the power saving mode, power is basically supplied only to the monitoring unit 9 and the interrupt generation unit. Therefore, conventionally, the remaining amount of paper is not detected in the power saving mode.

  Further, conventionally, the remaining amount of paper is determined based on the driving amount (driving time and number of rotations) of the motor from the lower limit state (the state where the mounting plate 11 is tilted) to the state where the paper feed roller 12 is lifted to the upper limit position. It was detected. Therefore, noise at the time of detecting the remaining amount of paper and the problem of power consumption due to the time required for detecting the remaining amount of paper are also reasons for not detecting the remaining amount of paper in the power saving mode.

  However, the computer 200 (management computer or each user's personal computer) that manages the multifunction peripheral 100 determines the necessity of paper replenishment or paper replacement even when the multifunction peripheral 100 is in the power saving mode. There is a request to check the remaining amount. Therefore, the multifunction peripheral 100 according to the present embodiment temporarily resumes power supply to the engine control unit 8 periodically even in the power saving mode, and informs the engine control unit 8 of the sheet information (paper remaining amount) of the sheet feeding unit 1. Amount and size). In other words, the image forming apparatus (for example, the multifunction peripheral 100) of the present invention has a communication unit 95 for communicating with the outside, and the communication unit 95 detects the remaining amount of paper detected by the detection processing unit (engine control unit 8). Is output to the outside as information.

  Information acquired by the engine control unit 8 in the power saving mode is given to the monitoring unit 9, and information such as the remaining amount of paper is given from the monitoring unit 9 to the external computer 200. Thus, accurate information such as the remaining amount of paper can be given to the external computer 200 or the like even in the power saving mode. Even when the power saving mode returns to the normal mode, accurate information such as the remaining amount of paper can be immediately displayed on the liquid crystal display unit 41 of the operation panel 4.

  Thus, an example of the remaining sheet amount detection flow in the power saving mode will be described with reference to FIG. In the MFP 100 according to the present exemplary embodiment, the remaining amount of paper is detected every predetermined time (for example, 15 minutes) after entering the power saving mode. And the start of FIG. 11 is the time of becoming a power saving mode. In the normal mode, power is supplied to the engine control unit 8 and the paper feeding unit 1, so that the remaining amount of paper may be detected in a shorter cycle.

  For example, the monitoring unit 9 (which receives power supply even in the power saving mode) confirms the passage of a certain time (step # 1). A separate timer may be provided. Specifically, whether a certain amount of time has elapsed since entering the power saving mode, a certain amount of time has elapsed since the previous detection of the remaining amount of paper in the power saving mode, or the previous paper in the power saving mode In order to detect the remaining amount, it is confirmed whether or not a predetermined time has elapsed since power was supplied to the engine control unit 8.

  Then, the monitoring unit 9 continues to check whether it is time to detect the remaining amount of paper in the power saving mode (No in Step # 1). When the timing is reached (Yes in Step # 1), the monitoring unit 9 By controlling switch unit 93, power supply unit 90 (temporarily) supplies power to engine control unit 8 (step # 2). Thereby, the setup (activation) of the engine control unit 8 is started (step # 3).

  Then, engine control unit 8 turns on lift motor 16 (step # 4). Then, engine control unit 8 recognizes the output voltage value of voltage output unit 19 (step # 5). Thereafter, the engine control unit 8 detects the remaining amount of paper based on the output voltage value and the remaining paper amount detection data (step # 6). That is, the image forming apparatus (for example, the multifunction peripheral 100) according to the present invention includes a placement plate 11 on which a plurality of sheets are stacked, a paper feed roller 12 that feeds the sheets, and sheets stacked on the placement plate 11. As a drive source for moving the mounting plate 11 so as to be in contact with the paper feed roller 12, the lift motor 16 whose back electromotive voltage changes according to the load, and the output voltage changes according to the back electromotive voltage of the lift motor 16. A voltage output unit 19, a detection processing unit (engine control unit 8) that recognizes the output voltage value of the voltage output unit 19 and detects the remaining amount of the paper placed on the placement plate 11 based on the output voltage value; ,including. More specifically, the image forming apparatus supplies power, and when the conditions for shifting to the power saving mode are satisfied, the power supply unit 90 stops power supply to the detection processing unit (engine control unit 8), and the normal mode. And the monitoring unit 9 that restarts the power supply from the power supply unit 90 to the detection processing unit (engine control unit 8) at least when the transition condition is satisfied. In the power saving mode, the monitoring unit 9 periodically The power supply from the power supply unit 90 to the detection processing unit (engine control unit 8) is temporarily resumed, and the detection processing unit (engine control unit 8) causes the lift motor 16 when the power supply is temporarily resumed. To detect the remaining amount of paper.

  The engine control unit 8 turns off the lift motor 16 (step # 7), and transmits data indicating the remaining amount of paper to the monitoring unit 9 (step # 8). When receiving the data indicating the remaining amount of paper, the monitoring unit 9 stops the power supply to the engine control unit 8 (step # 9). Then, the process returns to step # 1. This control is continued until shifting from the power saving mode to the normal mode.

(Correction of remaining paper detection)
Next, correction in the detected remaining paper amount detection according to the embodiment of the present invention will be described with reference to FIGS. FIG. 12 is an explanatory diagram showing an example of the concept of correction in the detected remaining paper amount detection according to the embodiment of the present invention. FIG. 13 is an explanatory diagram illustrating an example of a correction setting screen S2 for detecting the remaining amount of paper detected according to the embodiment of the present invention.

  The lift motor 16 has individual differences in characteristics. Even in the same load, the counter electromotive voltage generated may be different for each lift motor 16. Then, even if the same amount of sheets is stacked on the loading plate 11 for each sheet feeding unit 1, a difference may occur in the output voltage value of the voltage output unit 19.

  For example, the central vertical line in FIG. 12 indicates the range (range) of the maximum value Vmax1 and the minimum value Vmin1 of the output voltage value in the remaining sheet amount detection data. In other words, it is an ideal voltage range, and shows the range of the maximum value and the minimum value of the output voltage value in the ideal lift motor 16 that is a sample of the remaining paper amount detection data.

  However, depending on the characteristics of the lift motor 16, the maximum value Vmax2 of the output voltage value is the same as Vmax1 in the ideal range, as indicated by the left vertical line in FIG. 12, but the minimum value Vmin2 of the output voltage value. May be larger (may be smaller) than Vmax1 in the ideal range. Range 2 indicated by the left vertical line is narrower than the ideal range 1 (may be wider).

  Further, depending on the characteristics of the lift motor 16, the maximum value Vmax3 of the output voltage value is larger (may be smaller) in the ideal range as shown by the vertical line on the right side in FIG. The minimum value Vmin3 may be smaller (may be larger) than Vmax1 in the ideal range. Range 2 indicated by the vertical line on the right side is wider (may be narrower) than ideal range 1. Then, as the difference between the ideal range and the actual range of the lift motor 16 is larger, the error between the detected remaining amount of paper and the actual remaining amount of paper tends to increase.

  For example, in the multifunction machine 100 of the present embodiment, the output voltage value changes substantially linearly with respect to the magnitude of the load (torque). Further, the remaining amount detection is performed in a predetermined level (10 levels in the present embodiment). Therefore, the engine control unit 8 measures and measures the output voltage value when the lift motor 16 is operated in the absence of paper and the output voltage value when the lift motor 16 is operated in the full state. It is also possible to divide the range into a predetermined number of levels, update the remaining paper amount detection data, and perform correction in the remaining paper amount detection.

  Alternatively, a plurality of types of remaining paper amount detection data having different output voltage value ranges are stored in the storage unit 82, and the remaining amount detection data used by the engine control unit 8 in accordance with the actually measured range. May be selected to correct the remaining paper amount detection.

  An example of a method for measuring the maximum value and the minimum value of the output voltage value will be given. For example, the operation panel 4 is operated to display a sheet remaining amount detection correction setting screen S2 as shown in FIG. Then, according to the procedure displayed on the correction setting screen S2, every time the sheet in the sheet feeding unit 1 is emptied or full and the OK key K1 is pressed, the operation panel 4 passes through the main control unit 7, An instruction for measuring the output voltage value is given to the engine control unit 8. And the engine control part 8 operates the lift motor 16, and measures the output voltage value of an empty state and a full state. Then, for example, the measured range is divided by the total number of levels, a threshold for each level is set, and the remaining paper amount detection data is updated or selected.

  The output voltage value may be measured by an inspection at the time of shipment from the factory. However, filling the paper into a full state leads to an increase in man-hours for the inspection. Therefore, in the inspection at the time of shipment from the factory, the engine control unit 8 operates the lift motor 16 in the empty state, measures the output voltage value, and updates the remaining paper amount detection data based only on the output voltage value in the empty state. You may make a choice.

  That is, the storage unit 72 stores a first output value that is a voltage output value when the lift motor 16 is operated in an empty state where there is no sheet on the mounting plate 11, and the detection processing unit (engine control unit 8) Then, based on the difference between the output voltage value in the empty state in the remaining paper amount detection data and the first output value, the remaining paper amount detection data to be referred to is changed. Alternatively, the storage unit 72 may be a first output value that is a voltage output value when the lift motor 16 is operated in an empty state where there is no paper on the placement plate 11 and a full state where paper is stacked on the placement plate 11 to the full level. And a second output value that is a voltage output value when the lift motor 16 is operated in the state, and the detection processing unit outputs a range of output voltage values corresponding to an empty state and a full state in the remaining paper amount detection data And the remaining paper amount detection data to be referred to after confirming the range of the first output value and the second output value is changed.

  In this way, in the image forming apparatus (for example, the multifunction machine 100) according to the present invention, the detection processing unit (engine control unit 8) changes the back electromotive voltage of the motor according to the size (weight) of the load. Detects the remaining amount of paper placed on the placement plate 11 based on the output voltage value of the voltage output unit 19. Accordingly, since the drive time and the operation amount are measured, it is possible to detect the remaining amount of paper in a short time by shortening the time for which the lift motor 16 is turned on compared to the case where the motor is continuously rotated. . Further, noise generated by the operation of the lift motor 16 can be eliminated.

  In the power saving mode, the monitoring unit 9 periodically resumes power supply from the power supply unit 90 to the detection processing unit (engine control unit 8), and the detection processing unit temporarily supplies power. When the operation is resumed, the lift motor 16 is operated to detect the remaining amount of paper. Thereby, the remaining amount of paper can be detected even in the power saving mode. In addition, since the time required for detecting the remaining amount of paper is shorter than when the motor is continuously rotated to measure the driving time and the operation amount, the time for supplying power in the power saving mode can be shortened. Therefore, even if the power supply is temporarily performed in the power saving mode, the problem of noise does not occur, the power consumption can be reduced, and the energy saving effect of the power saving mode is not impaired.

  The detection processing unit (engine control unit 8) detects the remaining amount of paper based on the remaining paper amount detection data. Accordingly, the detection processing unit can easily detect the remaining amount of paper by comparing the output voltage value and the remaining amount detection data. In addition, since there are individual differences in the motor characteristics, the detection processing unit obtains the remaining paper amount detection data based on the difference between the output voltage value in the empty state in the remaining paper amount detection data and the first output value. change. As a result, even if the motor characteristics vary from individual to individual, the remaining amount of paper can be detected accurately.

  Further, the detection processing unit (engine control unit 8) checks the output voltage value range corresponding to the empty state and the full state, and the first output value range and the second output value range in the remaining paper amount detection data, and refers to them. Change the remaining paper detection data. As a result, the remaining amount of paper can be accurately detected even if the individual motor characteristics vary. The voltage output unit 19 also compares the reference voltage generated by dividing the input voltage to the lift motor 16 with a resistor and the voltage between the lift motor 16 and the resistor in a series circuit. 190. By configuring the circuit in this manner, the output of the voltage output unit 19 varies depending on the magnitude of the back electromotive voltage of the motor. Therefore, the remaining amount of paper can be detected based on the magnitude of the back electromotive voltage of the motor.

  The communication unit 95 outputs the remaining amount of paper detected by the detection processing unit (engine control unit 8) to the outside as information. Thereby, whether or not in the power saving mode, an accurate remaining paper amount can be given to the outside as information. The lift motor 16 is a DC motor in which the back electromotive voltage changes in proportion to the torque. As a result, the larger the back electromotive voltage, the greater the remaining amount of paper, and the smaller the back electromotive voltage, the less the remaining amount of paper. Based on the magnitude of the back electromotive voltage, the remaining amount of paper can be detected proportionally. Can do.

(Other embodiments)
Next, another embodiment will be described with reference to FIG. FIG. 14 is an explanatory diagram illustrating a configuration example of an image forming apparatus according to another embodiment. In the above-described embodiment, the example in which the engine control unit 8 in the multifunction peripheral 100 controls the lift motor 16 of the paper feeding unit 1 to detect the remaining amount has been described. However, as shown in FIG. 14A, the monitoring unit 9 and the paper feeding unit 1 may be connected, and the remaining amount detection may be performed using the CPU of the monitoring unit 9 or the like.

  In the case of FIG. 14A, the monitoring unit 9 supplies power to the sheet feeding unit 1 even in the power saving mode so that the remaining amount of paper can be detected not in the engine control unit 8 but also in the power saving mode. Power supply control is performed. For example, similarly to the engine control unit 8 and the like, the monitoring unit 9 uses the switch unit 93 to control power supply only to the paper feeding unit 1. The monitoring unit 9 temporarily supplies power only to the sheet feeding unit 1, operates the lift motor 16, and checks the output of the voltage output unit 19, thereby detecting the remaining amount even in the power saving mode. Can be done. In this case, the monitoring unit 9 functions as a detection processing unit. As a result, the remaining amount can be detected without activating the engine control unit 8, and less power can be consumed.

  Further, as shown in FIG. 14B, the sheet feeding unit 1 controls the sheet feeding control unit 1A (actually the operation of the sheet feeding unit 1 due to the limitation of the number of input / output ports of the engine control unit 8 or the like. For example, a CPU or a memory) may be provided. In this case, the paper feed control unit 1 </ b> A controls the paper feed unit 1 in response to an instruction from the engine control unit 8. For example, when the paper feeding unit 1 is an optional paper feeding device, a paper feeding control unit 1A may be provided.

  In the case of FIG. 14B, the paper feed control unit 1A may operate the lift motor 16 based on an instruction from the engine control unit 8, confirm the output of the voltage output unit 19, and detect the remaining amount. . Then, the paper feed control unit 1A transmits data indicating the remaining amount of paper to the engine control unit 8. Note that when the remaining amount of paper is detected even in the power saving mode, the power supply to the engine control unit 8 is restarted. Accordingly, the paper supply unit 1 is supplied with power so that the paper supply control unit 1A Performs remaining paper detection. In this case, the paper feed control unit 1A functions as a detection processing unit.

  Further, depending on the model, the main control unit 7 and the engine control unit 8 may be integrated without being divided, or the monitoring unit 9 and the main control unit 7 may be integrated. In any embodiment, if any one of the control units controls the lift motor 16 of the paper feeding unit 1 and the output voltage value of the voltage output unit 19 is input and the paper remaining amount detection data in the memory 92 is referred to. The remaining amount of paper can be detected. At this time, one of the control units functions as a detection processing unit.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in an image forming apparatus that includes a paper feeding unit and detects the remaining amount of paper.

DESCRIPTION OF SYMBOLS 1 Paper feed part 11 Mounting plate 12 Paper feed roller 16 Lift motor 19 Voltage output part 190 Differential amplifier circuit 1A Paper feed control part (detection process part) 8 Engine control part (detection process part)
82 storage unit 9 monitoring unit 90 power supply unit 95 communication unit 100 multifunction peripheral (image forming apparatus)

Claims (7)

A mounting plate on which a plurality of sheets are stacked;
A paper feed roller that feeds paper,
As a drive source for moving the mounting plate so that the paper loaded on the mounting plate is in contact with the paper feed roller, a lift motor whose back electromotive force changes according to the load,
A voltage output unit in which an output voltage changes according to a counter electromotive voltage of the lift motor;
Recognizing the output voltage value of the voltage output unit, and based on the output voltage value, a detection processing unit for detecting the remaining amount of paper placed on the mounting plate ,
A power supply for supplying power;
When the condition for shifting to the power saving mode is established, at least power supply from the power supply unit to the detection processing unit is stopped, and when the condition for shifting to the normal mode is established, at least from the power supply unit to the detection processing unit A monitoring unit for resuming the power supply of
In the power saving mode,
The monitoring unit periodically resumes power supply from the power supply unit to the detection processing unit,
When the power supply is temporarily resumed, the detection processing unit operates the lift motor, turns on the lift motor, and then outputs the output after a predetermined time when the output voltage value of the voltage output unit settles. An image forming apparatus comprising: detecting a remaining amount of paper by recognizing a voltage value; and turning off the lift motor when the output voltage value is recognized . A storage unit for storing paper remaining amount detection data for determining the remaining amount of paper with respect to the output voltage value;
The image forming apparatus according to claim 1 , wherein the detection processing unit detects a remaining amount of paper based on the remaining paper amount detection data. The storage unit stores a first output value that is the voltage output value when the lift motor is operated in an empty state where there is no paper on the mounting plate,
The detection processing unit changes the sheet remaining amount detection data to be referred to based on a difference between the output voltage value in the empty state in the remaining sheet amount detection data and the first output value. The image forming apparatus according to claim 2 . The storage unit includes a first output value that is the voltage output value when the lift motor is operated in an empty state where there is no paper on the mounting plate, and a full state in which the paper is stacked on the mounting plate until it is full. And storing the second output value that is the voltage output value when the lift motor is operated at
The detection processing unit confirms and refers to the range of the output voltage value corresponding to the empty state and the full state, and the range of the first output value and the second output value in the remaining paper amount detection data. The image forming apparatus according to claim 2 , wherein the remaining paper amount detection data to be changed is changed. A series circuit of the lift motor and the resistor is connected between the power source and the ground,
The voltage output unit includes a differential amplifier circuit that compares a reference voltage generated by dividing an input voltage to the lift motor with a resistor and a voltage between the lift motor and the resistor in the series circuit. the image forming apparatus according to any one of claims 1 to 4, characterized in that it comprises. A communication unit for communicating with the outside;
The communication unit image forming apparatus according to any one of claims 1 to 5, characterized in that externally outputs the paper remaining amount which the detection processing unit detects as information. The lift motor is an image forming apparatus according to any one of claims 1 to 6, characterized in that a DC motor which changes back electromotive force proportional to the torque.

Images