JP2009225373A - Image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus for performing medium conveyance by accurately detecting the presence of the medium. <P>SOLUTION: A composite apparatus 1 compares, in paper conveyance, a detection signal of a sensor such as a resist sensor 261 with a threshold stored in a memory such as NVRAM to determine the presence of paper. The apparatus further recalculates the threshold from a detection signal of the sensor when paper does not pass therethrough and that when paper passes therethrough to update the threshold of the memory, and uses the threshold after the updating of the memory for detection of the next paper. The apparatus performs such processing repeatedly. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus that accurately detects the presence / absence of medium conveyance.

  In an image processing apparatus such as an image forming apparatus such as a copying apparatus or a printer apparatus or an image reading apparatus such as a scanner apparatus, paper is conveyed to perform various image processing. For example, in an image forming apparatus such as a printer device, a sheet is conveyed from a paper feeding unit to a printing unit to form an image on the sheet. In an image reading device such as a scanner, an original sheet is placed at a reading position. An image of the conveyed original paper is read while being transported and stopped, ejected after reading the image of the stationary original paper, or transporting the original paper to a reading position.

  In such paper transport, it is necessary to detect whether the paper is transported appropriately, and to perform image processing such as printing processing and reading processing in accordance with the transport of the paper. Accurate detection is an important issue in appropriately performing image processing.

  Conventionally, paper detection is performed using a reflective or transmissive optical sensor. However, the output of such an optical sensor changes due to secular change, and the accuracy of paper detection deteriorates.

  Conventionally, a drive signal level supplied to a sensor that detects passage of a medium is controlled based on an output signal level of the sensor (see Patent Document 1).

JP-A-3-17796

  However, in the above prior art, since the sensor driving signal is only controlled based on the sensor output, it is necessary to improve the detection accuracy of the sensor.

  In other words, in the past, the presence or absence of paper was determined by comparing the sensor output with a fixed threshold in hardware, but the sensor deteriorated due to secular change, the sensor output decreased, and the upper and lower limits of the sensor If the difference between the values becomes small, the detection accuracy decreases with time, which may cause a jam in the paper conveyance path. In order to solve this problem, in the above prior art, the sensor output is detected and the sensor drive signal is controlled, but there is a limit to increasing the change in the sensor output depending on the presence or absence of paper. There is a problem that the sensor detection accuracy cannot be sufficiently coped with.

  SUMMARY An advantage of some aspects of the invention is that it provides an image processing apparatus that accurately detects the presence or absence of a medium such as paper.

  In order to solve the above problems, an image processing apparatus of the present invention includes at least one of a printing unit that transports a medium, prints an image on the transported medium, and an image reading unit that reads an image from the medium. In the image processing apparatus, a medium detection unit that outputs a detection signal having a different signal value depending on the presence or absence of the medium to be conveyed, a detection signal when the medium is not detected by the medium detection unit, and a state where the medium is present Threshold value calculation means for calculating a threshold value for determining the presence / absence of the medium from the detection signal, threshold value storage means for storing the threshold value, and comparison of the detection signal of the medium detection means with the threshold value stored in the threshold value storage means And determining means for determining the presence or absence of the medium.

  The image processing apparatus of the present invention includes a printed medium detection unit that detects whether or not the medium detected by the medium detection unit is a printed medium on which an image has already been printed, and the medium is printed. If the medium is a completed medium, it may be provided with correction means for correcting the threshold value of the threshold value storage means.

  Further, the image processing apparatus of the present invention detects the density of the image of the medium printed by the printing unit, the reverse conveyance path for reversing the medium that has passed through the printing unit, and conveying the medium to the printing unit again. Image density detecting means for detecting the medium on which the image is printed by the printing means, and the correcting means is based on the image density detected by the image density detecting means. The threshold value of the threshold value storage unit may be corrected.

  The image processing apparatus of the present invention further includes a reverse conveyance path that reverses the medium that has passed through the printing means and conveys the medium again to the printing means, and uses the reverse conveyance path at a predetermined timing. The threshold value calculation means calculates the threshold value based on the detection result of the medium detection means, and stores the calculation result in the threshold value storage means.

  Furthermore, the image processing apparatus of the present invention includes a paper type determination unit that determines the paper type, and a correction unit that corrects the threshold value of the threshold storage unit according to the paper type. Yes.

  The image processing apparatus according to the present invention further includes drive control means for controlling a value of a drive power source for driving the medium detection means based on detection signals of the medium detection means in a state where the medium is absent and a state where the medium is absent. It is characterized by being.

  According to the image processing apparatus of the present invention, from the detection signal in the absence of the medium and the detection signal in the presence of the medium by the medium detection means that outputs a detection signal having a different signal value depending on the presence or absence of the conveyed medium. A threshold value for determining the presence / absence of the medium is calculated, the threshold value is stored in the threshold value storage means, and the detection signal of the medium detection means is compared with the threshold value stored in the threshold value storage means. Therefore, even if the medium detection means is deteriorated, the medium presence / absence threshold value can always be corrected by the detection signal of the medium detection means, and the medium detection accuracy can be improved.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The range of this invention is unduly limited by the following description. However, not all of the configurations described in the present embodiment are essential requirements for the configuration of the present invention.

  1 to 8 are diagrams showing an embodiment of an image processing apparatus of the present invention, and FIG. 1 is a block diagram of a composite apparatus 1 to which an embodiment of the image processing apparatus of the present invention is applied.

  In FIG. 1, the multifunction apparatus 1 has a configuration in which a sheet feeding unit 100, a printer unit 200, and a scanner unit 300 are sequentially stacked. On the scanner unit 300, an automatic document feeder (hereinafter referred to as ADF). 400) is mounted.

  The printer unit 200 is an image forming unit including four sets of process cartridges 210Y, 210C, 210M, and 210K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). 210, an optical writing unit 230, an intermediate transfer unit 240, a secondary transfer unit 250, a registration roller pair 260, a belt fixing type fixing unit 270, a sheet reversing unit 280, and the like.

  The optical writing unit 230 includes a light source, a polygon mirror, an fθ lens, a reflection mirror, and the like (not shown). Laser light modulated based on image data of each color is stored in the process cartridges 210Y, 210C, 210M, and 210K of each color. Irradiating the surfaces of the photoconductors 211Y, 211C, 211M, and 211K, an electrostatic latent image of each color image is formed on the photoconductors 211Y, 211C, 211M, and 211K. Each of the process cartridges 210Y, 210C, 210M, and 210K is provided with an IC tag and is detachably mounted on the composite apparatus 1.

  The process cartridges 210Y, 210C, 210M, and 210K are not numbered, but include a charger, a developer, a cleaning device, a static eliminator, and the like around the drum-shaped photoconductors 211Y, 211C, 211M, and 211K. The charging device slidably rubs the charging rollers to which the AC voltage is applied to the photoconductors 211Y, 211C, 211M, and 211K, thereby uniformly charging the surfaces of the photoconductors 211Y, 211C, 211M, and 211K. The charger may be one that contacts another member such as a charging brush in place of the charging roller, and is not limited to a contact charging type, but a non-contact charging type scorotron charger. May be used.

  The surfaces of the photoconductors 211Y, 211C, 211M, and 211K that have been subjected to the charging process are irradiated with laser light L that is modulated and deflected based on the image data of each color by the optical writing unit 230, respectively. Electrostatic latent images for the respective colors are formed on the drum surfaces of 211C, 211M, and 211K, respectively.

  The process cartridges 210Y, 210C, 210M, and 210K supply the respective color toners 211Y, 211C, 211M, and 211K on which the electrostatic latent images are formed from the developing devices to develop the electrostatic latent images. Thus, a toner image of each color is formed. The toner images formed on the photoconductors 211Y, 211C, 211M, and 211K are intermediately transferred to an intermediate transfer belt 241 described later, and the surfaces of the photoconductors 211Y, 211C, 211M, and 211K after the intermediate transfer are left by a cleaning device. Toner is cleaned. The photoconductors 211Y, 211C, 211M, and 211K cleaned by the cleaning device are neutralized by the static eliminator along with the rotation, are uniformly charged by the charger, return to the initial state, and are again used for image formation. .

  The intermediate transfer unit 240 includes an intermediate transfer belt 241 and a first support roller 242, a second support roller 243, a third support roller 244, an intermediate transfer belt cleaning unit 246, and the like across the intermediate transfer belt 241. In addition, four intermediate transfer bias rollers are disposed at positions facing the respective photoreceptors 211Y, 211C, 211M, and 211K with the intermediate transfer belt 241 interposed therebetween. The intermediate transfer belt 241 is rotationally driven in a clockwise direction indicated by an arrow in FIG. 1 by rotating at least one of the first support roller 242, the second support roller 243, and the third support roller 244, and the first transfer roller 241 Along the intermediate transfer belt 241 between the support roller 242 and the second support roller 243, the photosensitive members 211Y, 211C, 211M, and 211K of the process cartridges 210Y, 210C, 210M, and 210K are arranged side by side. . The intermediate transfer belt cleaning unit 246 removes residual toner remaining on the intermediate transfer belt 241 after image transfer at a position downstream of the third support roller 244 in the rotation direction of the intermediate transfer belt 241.

  The intermediate transfer belt 241 is, for example, a multilayer belt in which an elastic layer is superimposed on a base layer made of a material that hardly stretches, such as a fluorine-based resin with a small elongation or a rubber material with a large elongation, such as a canvas. The surface of fluorine rubber or acrylonitrile-butadiene copolymer rubber is coated with, for example, a fluorine resin to form a coat layer with good smoothness.

  A secondary transfer unit 250 is disposed below the intermediate transfer unit 240, and an endless belt-like secondary transfer belt 251 is stretched by two stretching rollers 252 in the secondary transfer unit 250. ing. The secondary transfer belt 251 is rotated endlessly in the counterclockwise direction in FIG. 1 in accordance with the rotational drive of at least one of the stretching rollers 252, and the right side of FIG. The tension roller 252 provided sandwiches the intermediate transfer belt 241 and the secondary transfer belt 251 between the third support roller 244 of the intermediate transfer unit 240, and pushes up the intermediate transfer belt 241 to provide a third support roller. It is in a state of being pressed against 244 (secondary transfer nip).

  A secondary transfer bias having a polarity opposite to that of the toner is applied to the stretching roller 252 on the third support roller 244 side by a power source (not shown), and the application of the secondary transfer bias causes the color on the intermediate transfer belt 241 to be changed. A secondary transfer electric field for electrostatically moving the toner image from the intermediate transfer belt 241 toward the tension roller 252 side on the third support roller 244 side is formed.

  A sheet (recording medium) is fed to the secondary transfer nip so as to be synchronized with the color toner image on the intermediate transfer belt 241 by the registration roller pair 260, and the secondary transfer electric field is fed to the sheet fed to the secondary transfer nip. The color toner image is secondarily transferred from the intermediate transfer belt 241 to the sheet by the nip pressure.

  A registration roller pair 260 is disposed on the upstream side of the secondary transfer nip in the moving direction of the intermediate transfer belt 241. Between the registration roller pair 260, a sheet feeding unit 100, which will be described later, is connected to the printer unit 200. The fed paper is conveyed. In front of the registration roller pair 260 in the sheet conveyance direction, a registration sensor 261 for detecting the sheet conveyed to the registration roller pair 260 is provided. The registration sensor 261 is, for example, a reflection type photosensor including a light emitting element and a light receiving element. The resist sensor 261 emits light having a magnitude corresponding to the drive signal from the light emitting element to the paper conveyance path, and The reflected light is received by the light receiving element, and a detection signal obtained by photoelectrically converting the light received by the light receiving element is output.

  On the other hand, in the intermediate transfer unit 240, the color toner image formed on the intermediate transfer belt 241 enters the secondary transfer nip as the intermediate transfer belt 241 moves endlessly. The registration roller pair 260 adjusts the timing based on the detection result of the registration sensor 261 at a timing when the sheet is sandwiched between the rollers and the sheet sandwiched between the rollers is brought into close contact with the color toner image at the secondary transfer nip. At the secondary transfer nip, the color toner image on the intermediate transfer belt 241 is closely contacted with the sheet that has been fed with the timing adjusted, and is secondarily transferred onto the sheet, so that the full color image is printed on the white sheet. It becomes.

  The sheet on which the full-color image is formed in this way exits the secondary transfer nip as the secondary transfer belt 251 moves endlessly, and then is sent from the secondary transfer belt 251 to the fixing unit 270. In general, the registration roller pair 260 is often used while being grounded, but a bias may be applied to remove paper dust received from the paper. For example, when a bias is applied using a conductive rubber roller as the resist roller pair 260, and the conductive NBR rubber having a diameter of 18 mm and a surface of 1 mm is used, the electrical resistance is about 109 Ωcm in terms of the volume resistance of the rubber material. The paper surface after passing through the registration roller pair 260 to which a bias is applied in this way is slightly charged to the negative side, and a voltage is applied to the registration roller pair 260 in the secondary transfer from the intermediate transfer belt 241 to the paper. There are cases where the transfer conditions are changed and the transfer conditions are changed as compared with the case where the transfer is not performed. A voltage of about −800 V is applied to the intermediate transfer belt 241 to the third support roller 244 that is a toner transfer side (front side), and a voltage of about +200 V is applied to the stretching roller 252 that is the back side of the paper. Apply.

  The fixing unit 270 is configured such that the pressure roller 272 is pressed against the fixing belt 271 that is endlessly rotated while being heated, and the sheet received from the secondary transfer belt 251 is heated by the heating fixing belt 271. Meanwhile, the color image is fixed on the paper by being conveyed while being pressurized with the pressure roller 272.

  In the paper feeding unit 100, paper cassettes 102 are stored in multiple stages in a paper bank 101, and each of the paper feeding cassettes 102 can store a plurality of sheets of different paper types and paper sizes. Each paper feed cassette 102 is provided with a paper feed roller 103 that feeds the paper in the paper feed cassette 102 and a separation roller 104 that feeds the paper fed by the paper feed roller 103 one by one. The paper feed unit 100 is provided with a paper feed path 105 and a transport roller 106 for transporting paper fed from each paper feed cassette 102 to the printer unit 200. The paper feed unit 100 starts the paper feed operation almost simultaneously with the start of the document reading operation, and one of the paper feed rollers 103 is selectively rotated, so that the paper feed cassettes 102 housed in multiple stages in the paper bank 101 are fed. Send out paper from one. The sheet feeding unit 100 separates the fed sheets one by one by the separation roller 104 and enters the sheet feeding path 105, and then feeds the sheet to the sheet feeding path 203 in the printer unit 200 by the transport roller 106.

  In addition, the multifunction device 1 is provided with a manual feed tray 204 on the side surface of the printer unit 200, and a paper feed roller 205 and a separation roller 206 that separate and feed sheets on the manual feed tray 204 one by one. ing.

  When the manual feed tray 204 is selected, the multifunction apparatus 1 rotates the paper feed roller 205 to feed out the paper on the manual feed tray 204 and separates the paper by the separation roller 206 one by one. Paper is fed to the manual paper feed path 207.

  The multi-function apparatus 1 conveys the paper fed to the paper feed path 203 or the manual paper feed path 207 in the printer unit 200 via the registration roller pair 260 and the secondary transfer nip, and generates a color toner image. After the secondary transfer, the toner image is fixed by the fixing unit 270, and then discharged outside the apparatus.

  Although not illustrated, the multifunction apparatus 1 is provided with a conveyance path sensor that detects the presence or absence of the paper on the conveyance path of the paper on which the toner image is transferred at the secondary transfer nip. Controls the operation of the destination unit. Similar to the registration sensor 261, the transport path sensor is a reflection type or transmission type optical sensor in which the magnitude of the detection signal varies depending on the magnitude of the drive signal (drive power supply).

  Then, the sheet that has passed through the fixing unit 270 is discharged out of the apparatus via the pair of discharge rollers 201 in FIG. 1 and stacked on the stack unit 290 or is disposed below the fixing unit 270. Sent to the reversing unit 280.

  The sheet reversing unit 280 reverses the fed sheet upside down, and then again passes through the registration roller pair 260 so that the intermediate transfer belt 241 of the intermediate transfer unit 240 and the secondary transfer belt 251 of the secondary transfer unit 250 come into contact with each other. Then, the toner image is conveyed to the secondary transfer nip, and a color toner image is secondarily transferred to the other surface (back surface), and then discharged to the outside of the apparatus via the fixing unit 270. Whether the paper is sent from the fixing unit 270 to the paper discharge roller pair 201 or the paper reversing unit 280 is determined by switching the paper conveyance path by the switching claw 202.

  The scanner unit 300 includes a contact glass 301, a first traveling body 302 on which a light source and a first mirror are mounted, a second traveling body 303 on which a second mirror and a third mirror are mounted, an imaging lens 304, a reading sensor 305, and the like. The first traveling body 302 and the second traveling body 303 are housed in the main body housing of the composite apparatus 1 below the contact glass 301 and are arranged to be movable in the sub-scanning direction (left-right direction in FIG. 1). Has been. The scanner unit 300 irradiates the original set on the contact glass 301 from the light source on the first traveling body 302 with the reading light while the first traveling body 302 and the second traveling body 303 move in the sub-scanning direction. The reflected light from the original of the reading light is reflected by the first mirror on the first traveling body 302 to the second mirror on the second traveling body 303, and the incident light is reflected on the second traveling body 303 by the second mirror. The light is reflected on the third mirror, and the incident light is reflected in the direction of the imaging lens 304 by the third mirror. The imaging lens 304 condenses incident light on the reading sensor 305, and the reading sensor 305 photoelectrically converts the incident light to read an image on the document.

  The ADF 400 includes a document table 401, a paper feed roller 402, a separation roller 403, a conveyance roller 404, a conveyance belt 405, a paper discharge roller 406, a paper discharge table 407, and the like, and the contact glass 301 can be opened and closed. It is attached to the main unit housing.

  When the ADF 400 is opened, the upper surface of the contact glass 301 is opened, and a book-type document or the like can be set on the contact glass 301. When the ADF 400 is closed with the document set on the contact glass 301, It functions as a pressing plate that presses the document against the contact glass 301.

  When the ADF 400 is closed and a sheet-like document is set on the document table 401 and the start key is pressed by an operation display unit (not shown) to start reading, the document table 401 is guided by the paper feed roller 402. The upper document is fed out, and the fed document is separated one by one by the separation roller 403. The ADF 400 conveys the originals separated and sent one by one to the conveyance belt 405 by the conveyance roller 404, and conveys and conveys the conveyed original document to the reading position on the contact glass 301. When the reading of the original at the reading position on the contact glass 301 by the scanner unit 300 is completed, the ADF 400 conveys the original that has been read to the discharge roller 406 by the conveyance belt 405, and discharges the original by the conveyance roller 406. It is discharged onto the table 407.

  Next, the basic operation of the composite apparatus 1 will be described. When the multifunction apparatus 1 takes a copy of a document, for example, a bundle of sheet-shaped documents is set on a document table 401 of the ADF 400. However, when the original is a single-sided original (book-type original) that is closed in a book shape, the ADF 400 is opened, the contact glass 402 of the scanner 300 is exposed, and the single-sided original is placed on the contact glass 402. After being set, the single-bound original is pressed by the closed ADF 400.

  When the copy start key on the operation display unit (not shown) is pressed after the document is set in this way, the multifunction apparatus 1 starts the document reading operation by the scanner 300. However, when a sheet document is set on the ADF 400, the automatic conveying device 400 automatically conveys the sheet document to a reading position on the contact glass 402 prior to the document reading operation.

  In the document reading operation, first, both the first traveling body 302 and the second traveling body 303 start traveling in the sub-scanning direction, and light is emitted from the light source provided in the first traveling body 302 to the document. The reflected light reflected from the document surface is sequentially reflected by the first mirror on the first traveling body 302, the second mirror on the second traveling body 303, and the third mirror, and enters the imaging lens 304 to form an image. The light is incident on the reading sensor 305 by the lens 304. A reading sensor 305 photoelectrically converts incident light and reads an image of a document.

  In the multi-function apparatus 1, in parallel with the document reading operation, each device in the process cartridges 210Y, 210C, 210M, and 210K, the intermediate transfer unit 240, the secondary transfer unit 250, and the fixing unit 270 start driving, Y, C, M, and K toner images are formed on the photoreceptors 211Y, 211C, 211M, and 211K, and the composite apparatus 1 intermediates the toner images on the photoreceptors 211Y, 211C, 211M, and 211K. The toner images are superimposed and transferred on the transfer belt 241 to form four color toner images on the intermediate transfer belt 241.

  The multi-function apparatus 1 is housed in multiple stages in the paper bank 101 by starting the paper feeding operation of the paper feeding unit 100 and selectively rotating one of the paper feeding rollers 103 almost simultaneously with the start of the document reading operation. Transfer paper is sent out from one of the paper feed cassettes 102. The paper feed unit 100 separates the transfer paper fed from the paper feed roller 103 one by one by the separation roller 104 and enters the paper feed path 105, and feeds the transfer paper to the paper feed path 203 in the printer unit 200 by the transport roller 106. Make paper. The transfer paper may be fed from the manual feed tray 204 as described above as well as conveyed from the paper feed unit 100.

  The multi-function apparatus 1 adjusts the timing of the paper that is fed from the registration roller 260 to the transfer paper fed to the paper feed path 203 or the manual paper feed path 207 in the printer unit 200 based on the detection result of the reading sensor 305. Then, the toner is sent to the secondary transfer nip via the registration roller pair 260, and the four-color toner image on the intermediate transfer belt 241 is secondarily transferred to the transfer paper at the secondary transfer nip, and is fixed by the fixing unit 270. Discharge out of the machine.

  As shown in FIG. 2, the composite apparatus 1 is configured as a block, and includes a controller board 1000, an operation unit control board 1100 connected to the controller board 1000, an HDD (hard disk) 1201, and a LAN (Local Area Network). FCU (Facsimile Control Unit) 1204, engine control board 1300, SBU (scanner board) 1400, LDB (Laser Diode Control Board) 1500 connected to interface board 1202 and controller board 1000 by PCI (Peripheral Component Interconnect) bus 1203, AC control circuit 1600, PSU (Power Supply Unit) 1601, door switch (door SW) 1602, resistor 1603, solenoid (SOL) 1604, clutch (CL) 1605, toner end sensor 16 And a 6 and a main switch 1700 and the like. The PCI bus 1203 connects the controller board 1000, the FCU 1204, and the engine control board 1300, and transfers image data and control commands in a time division manner between them using the image data bus / control command bus.

  The controller board 1000 includes a central processing unit (CPU) 1001, a non-volatile random access memory (NVRAM) 1002, a static random access memory (SRAM) 1003, a read only memory (ROM) 1004, an application specific integrated circuit (ASIC) 1005, a work memory. 1006, a frame memory 1007, and the like.

  The CPU 1001 uses the SRAM 1003 as a working memory based on a program stored in the ROM 1004 to control the overall operation of the multifunction apparatus 1, and each application such as a scanner application, a facsimile application, a printer application, and a copy application Perform the function.

  The NVRAM 1002 is a memory that contains a lithium battery and retains the stored contents even when the power of the image processing apparatus 1 is turned off. The NVRAM 1002 backs up the SRAM 1003 and incorporates a clock mechanism. The clock mechanism built in the NVRAM 1002 counts the crystal reference clocks 32 and 768HZ mounted therein to generate the date and time, and the CPU 1001 stores the date and time input from the operation display unit in the internal register of the NVRAM 1002. After that, each time the power is turned on, it is used to detect the usable period of the device unit. In addition, when a new device unit is attached, the CPU 1001 may transmit a use start date and time for use time calculation.

  The work memory 1006 is a working memory for image development (conversion from document data to image data) used in the printer application, and the frame memory 1007 is a read image that is immediately printed while power is continuously supplied. And a working memory for temporarily storing image data of written images. The ASIC 1005 executes various processing such as control processing for controlling the periphery of the CPU 1001 such as system bus control, frame memory control, and FIFO of the controller board 1000 and various image processing.

  The HDD 1201 is an application database that stores various application programs (copy application program, printer application, facsimile application, scanner application, etc.), process cartridges 210Y, 210C, 210M, and 210K of the multifunction apparatus 1, and read images and write data. It is used as an image database for storing image data of an image, that is, image data and document data, and both a physical interface and an electrical interface are connected to the controller board 1000 through an interface compliant with ATA / ATAPI-4.

  The operation unit control board 1100 includes an LCDC (ASIC) 1101, a CPU 1102, a ROM 1103, a RAM 1104, and the like. An operation control program for controlling input reading and display output of the operation unit control board 1100 is written in the ROM 1103. Based on the operation control program in the ROM 1103, the CPU 1102 communicates with the controller board 1000 while using the RAM 1104 as a working memory, and operates the operation display unit to input a system setting by the user. The display control and input control for displaying the setting contents and status of the system to the user are performed.

  The SBU 1400 is incorporated in the scanner unit 300, and includes RGB analog ASICs 1401 to 1403, an output I / F (interface) 1404, a timing generation / control circuit 1405, and the like. The reading sensor 305 of the scanner unit 300 uses a three-line color CCD, generates EVENch / ODDch R, G, and B image signals and outputs them to the analog ASICs 1401, 1402, and 1403 for RGB, respectively.

  Each of the analog ASICs 1401 to 1403 samples and holds the image signal from the reading sensor 305 by an internal sample and hold circuit based on the timing signal of the timing generation / control circuit 1405, and performs A / D conversion. The image data is converted into image data, shading corrected, and sent to the engine control board 1300 via the output I / F 1404 and the image data bus.

  The engine control board 1300 includes an IPP (Image Processing Processor) 1301, a CPU 1302, an NVRAM 1303, an SRAM 1304, an I / O ASIC 1305, an I / O ASIC 1306, a ROM 1307, and an interface circuit 1308. The main switch 1602, the solenoid 1604, and the clutch 1605 are provided. , A motor 1606, a high-voltage power supply 1607, a registration sensor 261, a toner end sensor 1606, a non-contact communication unit 1607, and the SBU 1400 and LDB 1500 are connected, and the CPU 1001 of the controller board 1000 and an operation unit control board A serial interface for transmitting and receiving signals to and from the CPU 1102 of 1100 is provided.

  The IPP 1301 is a programmable arithmetic processing unit that performs image processing. Separation generation (determination of whether an image is a character area or a photographic area: image area separation), background removal, scanner gamma conversion, filter, color correction, scaling, image Processing, printer gamma conversion, and gradation image processing are performed. The IPP 1301 corrects signal deterioration (scanner system signal deterioration) associated with quantization of the image data transferred from the SBU 1404 into an optical system and a digital signal, and writes the corrected image data into the frame memory 1007.

  The ROM 1307 stores an engine control program, a detection control program for executing the detection control process of the present invention to be described later, and necessary data. The CPU 1302 uses the SRAM 1304 as a working memory based on the program of the ROM 1307, and The engine operation is controlled to control the copy operation, printer operation, and scanner operation. The NVRAM 1303 includes an SRAM and a memory that detects power-off and stores the stored contents of the SRAM in the EEPROM. The I / O ASICs 1305 and 1306 include a solenoid 1604, a clutch 1605, a motor 1606, and the like that control the multifunction device 1. And I / O control of the composite apparatus 1 including analog control such as a registration sensor 261, a toner end sensor 1606, and other toner density sensors (P sensor, T sensor).

  The interface circuit 1308 interfaces with the non-contact communication circuit 1607, and the non-contact communication unit 1607 communicates with the IC tag of each unit of the composite apparatus 1, for example, the units such as the process cartridges 210Y, 210C, 210M, and 210K. Do. Communication between the interface circuit 1308 and the non-contact communication unit 1607 is performed by a two-wire (I2CBUS) serial interface. The PSU 1601 is a unit that supplies power to control the composite apparatus 1, and commercial power is supplied from the main switch 1602. Further, the PSU 1601 confirms the mounting of each unit when the switch 1602 is turned on.

  The door switch 1602 is grounded via a resistor 1603, and detects that the door has been opened or closed due to replacement of the door of the composite apparatus 1, for example, the process cartridges 210Y, 210C, 210M, and 210K or replenishment of paper. Then, the detection result is output to the engine control board 1300. When the door switch 1602 is turned on / off, the engine control board 1300 may confirm that the unit has been replaced.

  The CPU 1302 transmits the number of copies and the copy sheet size to the IC tag of the mounting unit for each copy or after a series of copy jobs, and the IC tag of the mounting unit stores the usage history as a mounting history. Or it is used to detect the life of the parts that make up the mounting unit.

  When the CPU 1302 reads the output of the toner end sensor 1606 and detects that the toner in the process cartridges 210Y, 210C, 210M, and 210K has run out, the IC tags of the process cartridges 210Y, 210C, 210M, and 210K in which the toner has run out. Is written to the effect that the remaining amount of toner is “0”.

  The LDB 1500 includes LDBs 1501 to 1504 for each color of Y, C, M, and K. Under the control of the CPU 1302 of the engine control board 1300, lighting control is performed based on the image signal, and the photoreceptors 211Y, 211C, 211M, An electrostatic latent image is formed on 211K.

  The LAN interface board 1202 is connected to a LAN such as an in-house LAN and performs a communication interface between the LAN and the controller board 1000. The LAN interface board 1202 is equipped with a PHY (physical media interface) chip, and the LAN interface board 1202 and the controller board 1000 are connected by standard communication interfaces of a PHY chip I / F and an I2C bus I / F. ing. The controller board 1000 performs communication with an external device via the LAN interface board 1202.

  A telephone line is connected to the FCU 1204. The FCU 1204 automatically picks up a call from the line by capturing the line, sending a selection signal as a destination telephone number, detecting an incoming call, and the like. Then, the automatic call processing to the line is performed, the facsimile control signal is exchanged with the partner facsimile machine, and the G3 and G4 facsimile communication procedures are executed.

  The composite device 1 includes a ROM, an EEPROM (Electrically Erasable and Programmable Read Only Memory), an EPROM, a flash memory, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), a CD-RW (Compact Disc Rewritable), a DVD ( A detection accuracy adjustment processing program for executing the detection accuracy adjustment processing of the present invention recorded on a recording medium readable by the composite apparatus 1 such as a digital video disk (SD), a secure digital (SD) card, or a magneto-optic disc (MO). Is incorporated into the ROM 1302 and the HDD 1201 of the engine control board 1300, and is constructed as a composite apparatus 1 that executes detection accuracy adjustment processing that improves sensor accuracy, which will be described later. This detection accuracy adjustment processing program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark), an object-oriented programming language, or the like. Can be stored and distributed.

  Next, the operation of this embodiment will be described. The composite apparatus 1 of this embodiment performs image processing while improving the detection accuracy of sensors such as the registration sensor 261 and the conveyance path sensor.

  That is, the composite apparatus 1 detects various operation states of the composite apparatus 1 with various sensors as described above, and controls the operation based on the detection results. For example, the CPU 1302 of the engine control board 1300 The registration sensor 261 controls the driving of the registration roller pair 260 to adjust the position of the toner image on the intermediate transfer belt 241 and the paper, thereby controlling the transfer of the toner image onto the paper. ing.

  The sensors such as the registration sensor 261 and the conveyance path sensor output a detection signal corresponding to the magnitude of a driving signal (driving power source) such as a photo sensor, and the engine control board 1300 uses the detection signal as a predetermined threshold value. By comparison, operation control is performed by determining whether or not a detection target such as paper is detected.

  However, sensors such as the registration sensor 261 are deteriorated due to secular change, and the detection sensitivity is lowered.

  Therefore, the composite apparatus 1 according to the present embodiment performs detection accuracy adjustment processing for detecting the sensitivity of sensors such as the registration sensor 261 and the conveyance path sensor and adjusting the threshold setting at a predetermined timing.

  In the following description, the case of the registration sensor 261 will be described in order to make the description easy to understand. The present invention can be similarly applied to a sensor that outputs a detection signal corresponding to the above.

  In other words, as shown in FIG. 3, when the multifunction apparatus 1 performs a printer operation or a copy operation, the engine control board 1300 conveys the sheet from the sheet feeding unit 100 to the printer unit 200 (step S101), and the registration sensor. When the sheet 261 detects the sheet (step S102), the driving of the registration roller pair 260 is temporarily stopped (step S103), and the timing is adjusted to the timing at which the sheet is brought into close contact with the toner image at the secondary transfer nip, thereby adjusting the registration roller pair 260. (Step S104).

  In the engine control board 1300, the CPU 1302 acquires a detection signal when the sheet is not conveyed from the registration sensor 261, stores it in the NVRAM 1303, and then conveys the sheet from the sheet feeding unit 100 to register the sheet. A detection signal when the sheet is conveyed to the sensor 261 is acquired and stored in the NVRAM 1303 (step S105). Then, the CPU 1302 acquires a detection signal when the paper has not passed and a detection signal when the paper has passed, calculates a threshold for determining the presence of paper (step S106), and stores the calculated threshold in the NVRAM 1303 (step S106). S107).

  In this manner, with the sheet determination threshold value stored in the NVRAM 1303, the CPU 1302 conveys the sheet from the registration roller pair 260, and when the sheet passes through the registration sensor 261 (step S108), the detection accuracy process ends. In printing on the next sheet, when the sheet is transported and passes the registration sensor 261, the threshold value is taken out from the NVRAM 1303 to determine the presence of the sheet, and the detection signal when the sheet has not passed is obtained. Then, the process of acquiring the detection signal when the paper passes and recalculating the threshold value and storing it in the NVRAM 1303 is repeated every time the paper is conveyed (steps S101 to S108).

  As described above, the multifunction apparatus 1 according to the present embodiment can always update the threshold for determining the presence / absence of a sheet while confirming the deterioration state of a sensor such as the registration sensor 261. The presence / absence of the sheet can be determined with high accuracy by correcting the determination threshold.

  In addition, when the multifunction apparatus 1 performs so-called back paper printing in which a sheet is printed on one side and the other side is printed, the engine control board 1300 has a threshold stored in the NVRAM as shown in FIG. After the threshold value is corrected by a method such as multiplying by a correction value set in advance for the backing paper to determine the presence or absence of paper, the presence or absence of paper is determined as in FIG. In the case of the back paper, since printing is performed on the other side, the reflectance decreases, the amount of reflected light from the paper decreases, and the detection signal value decreases. Therefore, the change in the detection signal of the registration sensor 261 due to the passage of the sheet is small, and it is necessary to correct the sheet presence / absence detection threshold accordingly. In FIG. 4, the same processing steps as those in FIG. 3 are given the same step numbers to simplify the description.

  That is, as shown in FIG. 4, in the multifunction apparatus 1, the CPU 1302 checks whether the paper has already been printed on one side (step S201). If the paper is a back paper, the CPU 1302 sets in advance for the back paper from the NVRAM 1303. The corrected correction value is acquired (step S202), and the threshold value of the registration sensor 261 is corrected by a method such as multiplying the threshold value by the correction value (correction data) (step S203). Whether or not this paper is a backing paper is determined by the method of detecting the density of the surface opposite to the printing surface of the paper with an optical sensor, the user's input operation indicating that the paper is the backing paper on the operation display section, and the printing mode is duplex printing. Therefore, it can be determined based on whether the printing is performed on the back side.

  When the CPU 1302 corrects the threshold value of the registration sensor 261 for the back paper, the CPU 1302 performs processing similar to that shown in FIG. 3 and performs sheet detection control that involves recalculation of the threshold value of the registration sensor 261 (steps S101 to S108).

  In step S201, when the paper is not the back paper, the CPU 1302 does not need to perform the correction for the back paper. Therefore, the CPU 1302 proceeds to step S101 and performs the same processing as in FIG. Detection accuracy adjustment processing with threshold recalculation is performed (steps S101 to S108).

  In this way, it is possible to detect a sheet printed on the back surface with high accuracy, and to improve control accuracy.

  Furthermore, in the multi-function apparatus 1, paper feed cassettes 102 are accommodated in multiple stages in the paper feed unit 100, and each paper feed cassette 102 can accommodate a plurality of sheets having different paper sizes. Since the reflectivity varies depending on the type of paper, the CPU 1302 of the engine control board 1300 performs detection with paper type determination that performs appropriate paper presence determination for each paper type, as shown in FIGS. 5 and 6. Perform accuracy adjustment processing. 5 and FIG. 6, the same processing steps as those in FIG. 3 are denoted by the same step numbers, and the description thereof will be simplified.

  That is, as shown in FIG. 5, the CPU 1302 checks whether the type of paper to be fed (medium type) is A type (step S301). If the paper is A type, the CPU 1302 sets it for A type. The corrected correction value (correction data) is acquired (step S302), and the threshold value of the registration sensor 261 is corrected by a method such as multiplying the threshold value by the correction value (step S308).

  If the paper is not type A in step S301, the CPU 1302 checks whether the paper is type B (step S303). If the paper is type B, the correction value (correction) set for the B type from the NVRAM 1303 is checked. Data) is acquired (step S304), and the threshold value of the registration sensor 261 is corrected by a method such as multiplying the threshold value by the correction value (step S308).

  If the paper is not type B in step S303, the CPU 1302 checks whether the paper is type C (step S305). If the paper is type C, the correction value (correction) set for the C type from the NVRAM 1303 is checked. Data) is acquired (step S306), and the threshold value of the registration sensor 261 is corrected by a method such as multiplying the threshold value by the correction value (step S308).

  If it is determined in step S305 that the paper is not type C, the CPU 1302 determines that the paper is type D, acquires a correction value (correction data) set for the type D from the NVRAM 1303 (step S307), and registers. The threshold value of the sensor 261 is corrected by a method such as multiplying the threshold value by the correction value (step S308).

  In this way, when the threshold value of the registration sensor 261 is corrected for the paper type, the process proceeds to the process of FIG. 6, the same process as in FIG. 3 is performed, and the detection accuracy adjustment process with the threshold value recalculation of the registration sensor 261 is performed. (Steps S101 to S108). For example, the paper type of the paper set in the paper feed cassette 102 is input in advance for each paper feed cassette 102 and stored in the NVRAM 1303, and is used for printing on the operation display unit by the user. Based on the selection, the paper type is determined.

  In this way, even when the types of paper are different, the paper can be detected with high accuracy.

  Further, as described above, the multifunction device 1 is provided on the conveyance path of the paper on which the toner image is transferred at the secondary transfer nip of the plotter unit 200 and detects the presence or absence of the paper conveyed on the conveyance path. A sensor is provided, and the CPU 1302 of the engine control board 1300 determines the presence / absence of paper conveyance (paper presence / absence) based on the detection result of the conveyance path sensor, and controls subsequent operations. Since the toner image is transferred to the paper on the conveyance path after the secondary transfer nip, if a reflection type photo sensor is used as the conveyance path sensor, the transfer position of the toner image and the conveyance path sensor Depending on the detection position on the paper, the output level of the conveyance path sensor is lowered.

  Therefore, the CPU 1303 of the engine control board 1300 acquires the detection signal when the paper has not passed and the detection signal when the paper has passed from the conveyance path sensor, stores them in the NVRAM 1303, and detects the detection signal when the paper has not passed and the paper passage time. A threshold for determining the presence of a sheet is calculated from the detected signal and stored in the NVRAM 1303, and the process for determining the presence or absence of the next sheet using the threshold of the NVRAM 1303 is repeated. The image density of the printed image is determined, the threshold value of the NVRAM 1303 is corrected based on the determined image density, and the presence / absence determination of the sheet is performed.

  Note that the image density is determined based on, for example, an image signal that the CPU 1303 receives from the controller board 1000 and outputs to the LDB 1500.

  For example, in the case of the registration sensor 261, as shown in FIG. 7, a detection accuracy adjustment process involving correction of the threshold value of the registration sensor 261 with the toner density value is performed. In FIG. 7, the same processing steps as those in FIG. 3 are given the same step numbers to simplify the description.

  That is, as shown in FIG. 7, when the multifunction apparatus 1 performs a printer operation or a copying operation, the engine control board 1300 conveys the sheet from the sheet feeding unit 100 to the printer unit 200 (step S101), and the registration sensor. When the sheet 261 detects the sheet (step S102), the driving of the registration roller pair 260 is temporarily stopped (step S103), and the timing is adjusted to the timing at which the sheet is brought into close contact with the toner image at the secondary transfer nip, thereby adjusting the registration roller pair 260. (Step S104).

  The CPU 1302 acquires the toner density value (step S401), acquires a detection signal when the sheet is not conveyed from the registration sensor 261, stores the detection signal in the NVRAM 1303, and then transfers the sheet from the sheet feeding unit 100. A detection signal when the sheet is conveyed and conveyed from the registration sensor 261 is acquired and stored in the NVRAM 1303 (step S105).

  Next, the CPU 1302 corrects the threshold value of the registration sensor 261 of the NVRAM 1303 based on the toner density value (step S402). The CPU 1302 acquires the detection signal when the paper has not passed and the detection signal when the paper has passed, calculates a threshold for determining the presence of the paper (step S106), and stores the calculated threshold in the NVRAM 1303 (step S107). .

  In this manner, with the sheet determination threshold value stored in the NVRAM 1303, the CPU 1302 conveys the sheet from the registration roller pair 260, and when the sheet passes through the registration sensor 261 (step S108), the detection accuracy process ends. In printing on the next sheet, when the sheet is transported and passes the registration sensor 261, the threshold value is taken out from the NVRAM 1303 to determine the presence of the sheet, and the detection signal when the sheet has not passed is obtained. Then, the process of acquiring the detection signal when the paper passes and recalculating the threshold value and storing it in the NVRAM 1303 is repeated every time the paper is conveyed (steps S101 to S108).

  In this way, when detecting the presence / absence of an image-formed sheet, the threshold for determining the presence / absence of the sheet can be corrected according to the density of the image, and the presence / absence of the image-formed sheet can be detected with high accuracy. be able to. Although FIG. 7 illustrates the case where the present invention is applied to the registration sensor 261, the present invention can be similarly applied to the case of the conveyance path sensor or the like.

  Further, the CPU 1303 of the engine control board 1300 determines the image density and image position of the image printed by the plotter unit 200 and corrects the threshold value of the NVRAM 1303 based on the image density when determining the presence or absence of paper by the conveyance path sensor. Then, it is determined whether there is an image whose density exceeds the upper and lower limit values for which the threshold correction result is set in advance, for example, the upper and lower limit values of the detection signals of the registration sensor 261 and the conveyance path sensor. When the CPU 1303 determines that there is an image whose threshold correction result exceeds the upper and lower limit values, the CPU 1303 stops acquiring the detection signal from the conveyance path sensor at the image position of the determined image, and the image position where the density is high Only the detection signal from the conveyance path sensor other than the above is acquired, and the threshold value is calculated and the presence / absence of the sheet is determined.

  In this way, when detecting the presence / absence of an image-formed sheet, it is possible to prevent erroneous determination of the presence / absence of the sheet due to the detection signal at a position where the detection signal level is extremely lowered. Presence / absence can be detected with high accuracy.

  The image density and the image position are determined based on, for example, an image signal that the CPU 1303 receives from the controller board 1000 and outputs to the LDB 1500.

  Further, as illustrated in FIG. 8, the multifunction apparatus 1 may adjust the detection accuracy by inputting the threshold value of the NVRAM 1303 from the operation display unit. In FIG. 8, the same processing steps as those in FIG. 3 are given the same step numbers to simplify the description.

  That is, the CPU 1302 recalculates the threshold value of the registration sensor 261 in the case of the registration sensor 261, as shown in the right side of FIG. While improving the detection accuracy, paper detection is performed by the registration sensor 261 to carry the paper (steps S101 to S108).

  On the other hand, as shown on the left side of FIG. 8, when the threshold adjustment mode is selected by the operation display unit and the threshold operation is started (step S501), the operation unit control board 1100 receives the threshold value from the NVRAM 1303 of the engine control board 1300. And the threshold adjustment screen is displayed on the display of the operation display unit. When a threshold correction operation is performed on the threshold adjustment screen (step S502), the CPU 1302 corrects the threshold of the NVRAM 1303 (step S601), and stores the corrected threshold in the NVRAM 1303 of the engine control board 1300 (step S601). S107).

  Thereafter, when the end of the threshold adjustment mode on the operation display unit is operated, the threshold correction processing is ended (step S502).

  Then, in the detection of the sheet conveyance, the registration sensor 261 detects the sheet using the corrected threshold value of the NVRAM 1303 (step S108).

  Although FIG. 8 shows a case where the present invention is applied to the registration sensor 261, the present invention can be similarly applied to a sensor such as a conveyance path sensor.

  In this way, it is possible to cause the sensor such as the registration sensor 261 and the conveyance path sensor to detect the sheet with the detection accuracy intended by the user, and to improve the usability.

  Further, the CPU 1303 of the engine control board 1300 conveys the sheet from the sheet feeding unit 100 or the manual feed tray 204 to the printer unit 200 and conveys it to the printer unit 200 when the multifunction device 1 is not used for a predetermined period. The operation is performed to pass the conveyed paper through the registration sensor 261, the registration roller pair 260, the secondary transfer unit 250, the fixing unit 270, the switching claw 202, and the paper reversing unit 280 to the registration sensor 261 and the registration roller pair 260 again. After a predetermined number of times, detection signals when the paper has not passed and detection signals when the paper has passed are obtained from each sensor such as the registration sensor 261 and the conveyance path sensor, and stored in the NVRAM 1303. NVRAM is calculated by calculating a threshold value for determining the presence of a sheet from a detection signal when the sheet passes. Stores 303, by repeating the detection accuracy adjustment process for determining the presence or absence of the next sheet, reconfirmations process to reaffirm the data to be stored in NVRAM1303 using the threshold of the NVRAM1303.

  In this way, it is possible to prevent erroneous determination of the presence / absence of a sheet due to deterioration of each sensor during the unused period of the multifunction apparatus 1, and to improve the accuracy of determining the presence / absence of a sheet.

  Further, the CPU 1303 of the engine control board 1300 acquires a detection signal when the paper is not passed and a detection signal when the paper is passed from each sensor such as a drive signal (drive power supply) supplied to the registration sensor 161 and the conveyance path sensor. A drive signal (drive power supply) stored in the NVRAM 1303 and supplied to the registration sensor 161 and the conveyance path sensor is adjusted from the detection signal when the paper is not passed and the detection signal when the paper is passed.

  In this way, the signal level of the detection signal can be set to an appropriate level, and the paper presence / absence determination accuracy can be further improved.

  In the above description, the case where the present invention is applied to a sensor such as a registration sensor 261 or a conveyance path sensor that detects the presence or absence of paper has been described. However, the present invention is not limited to a sensor that detects the presence or absence of paper. The present invention can be applied to a sensor whose detection signal changes depending on the magnitude of the drive signal (drive power supply), such as a sensor for detecting the light and other reflective or transmissive optical sensors.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to that described in the above embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

  The present invention relates to a copying apparatus, a facsimile apparatus, a composite apparatus, a scanner apparatus, etc., which detects the presence or absence of a detection target using a detecting means whose detection signal changes according to the magnitude of a driving signal (driving power supply) and controls image processing. It can be used for an image processing apparatus.

1 is a block configuration diagram of a composite apparatus to which an embodiment of the present invention is applied. The block block diagram of the compound apparatus of FIG. The flowchart which shows the detection accuracy adjustment process of the registration sensor by a composite apparatus. The flowchart which shows the detection accuracy adjustment process accompanied by the threshold value correction based on the back paper of the registration sensor by a composite apparatus. 9 is a flowchart showing detection accuracy adjustment processing with threshold correction based on the paper type of a registration sensor by the composite apparatus. 6 is a flowchart showing processing subsequent to the detection accuracy adjustment processing in FIG. 9 is a flowchart illustrating detection accuracy adjustment processing with threshold correction based on toner density of a registration sensor by a composite apparatus. The flowchart which shows the detection accuracy adjustment process accompanied by the threshold value correction | amendment according to correction | amendment operation by a multifunctional device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compound apparatus 100 Paper feed part 101 Paper bank 102 Paper feed cassette 103 Paper feed roller 104 Separation roller 105 Paper feed path 106 Conveyance roller 200 Printer part 201 Paper discharge roller pair 202 Switching claw 203 Paper feed path 204 Manual feed tray 205 Paper feed roller 206 Separating roller 207 Manual paper feed path 210 Image forming units 210Y, 210C, 210M, 210K Process cartridges 211Y, 211C, 211M, 211K Photoconductor 230 Optical writing unit 240 Intermediate transfer unit 241 Intermediate transfer belt 242 First support roller 243 First 2 support roller 244 3rd support roller 246 intermediate transfer belt cleaning unit 250 secondary transfer unit 251 secondary transfer belt 252 stretching roller 260 registration roller pair 261 registration sensor 27 Fixing unit 271 Fixing belt 272 Pressure roller 280 Paper reversing unit 290 Stack unit 300 Scanner unit 301 Contact glass 302 First traveling body 303 Second traveling body 304 Imaging lens 305 Reading sensor 400 Automatic document feeder 401 Document base 402 Paper feed Roller 403 Separating roller 404 Conveying roller 405 Conveying belt 406 Discharging roller 407 Discharging stand 1000 Controller board 1001 CPU
1002 NVRAM
1003 SRAM
1004 ROM
1005 ASIC
1006 Work memory 1007 Frame memory 1100 Operation unit control board 1101 LCDC
1102 CPU
1103 ROM
1104 RAM
1201 HDD (hard disk)
1202 LAN interface board 1203 PCI bus 1204 FCU
1300 Engine control board 1301 IPP
1302 CPU
1303 NVRAM
1304 SRAM
1305, 1306 I / O ASIC
1307 ROM
1308 Interface circuit 1400 SBU
1401 to 1403 Analog ASIC
1404 Output I / F
1405 Timing generation / control circuit 1500 LDB
1600 AC control circuit 1601 PSU
1602 Door switch 1603 Resistance 1604 Solenoid (SOL)
1605 Clutch (CL)
1606 Toner end sensor 1700 Main switch

Claims (6)

  In an image processing apparatus comprising at least one of a printing unit that transports a medium and prints an image on the transported medium and an image reading unit that reads an image from the medium, a signal that varies depending on the presence or absence of the transported medium Medium detection means for outputting a detection signal of a value, threshold calculation for calculating a threshold for judging the presence or absence of the medium from the detection signal in the absence of the medium by the medium detection means and the detection signal in the presence of the medium Means, threshold value storing means for storing the threshold value, and determination means for comparing the detection signal of the medium detecting means with the threshold value stored in the threshold value storing means to determine the presence or absence of the medium. An image processing apparatus.   The image processing apparatus includes: a printed medium detection unit that detects whether the medium detected by the medium detection unit is a printed medium on which an image has already been printed; and the medium is a printed medium. The image processing apparatus according to claim 1, further comprising: a correction unit that corrects the threshold value of the threshold value storage unit.   The image processing apparatus includes a reverse conveyance path that reverses the medium that has passed through the printing unit and conveys the medium again to the printing unit, and an image density detection that detects a density of an image of the medium printed by the printing unit. And the medium detecting means detects the medium on which the image is printed by the printing means, and the correcting means is provided on the basis of the image density detected by the image density detecting means. The image processing apparatus according to claim 1, wherein the threshold value is corrected.   The image processing apparatus includes a reversing conveyance path that reverses the medium that has passed through the printing unit and conveys the medium again to the printing unit, and cyclically conveys the medium using the reversing conveyance path at a predetermined timing. The threshold calculation unit calculates the threshold based on the detection result of the medium detection unit, and stores the calculation result in the threshold storage unit. The image processing apparatus according to 1.   2. The image processing apparatus according to claim 1, further comprising: a sheet type determining unit that determines the sheet type; and a correcting unit that corrects the threshold value of the threshold storage unit according to the sheet type. The image processing apparatus according to claim 4.   The image processing apparatus includes a drive control unit that controls a value of a driving power source that drives the medium detection unit based on detection signals of the medium detection unit in a state where the medium is not present and a state where the medium is present. An image processing apparatus according to any one of claims 1 to 5.

Images