JP2006267682A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus ensuring improved output image quality. <P>SOLUTION: The image forming apparatus includes: an image carrier; an exposure means; a developing means for developing a latent image formed by the exposure means; an intermediate transfer belt for conveying a developed toner image to a transfer position on a recording medium; a primary transfer means for transferring the toner image, developed on the image carrier, to the recording medium; and a secondary transfer means for transferring the toner image, transferred to the intermediate transfer belt, to the recording medium. The image forming apparatus is provided with: one or more fur brushes disposed in contact with the transfer belt in order that toner passed through the secondary transfer means is removed from the intermediate transfer belt; a high voltage generating means for applying a high voltage to each fur brush, thereby electrostatically attracting the toner thereto; a detecting means for detecting an amount of toner passed through the fur brushes; and a control means for performing predetermined control in accordance with the output level of the detecting means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an intermediate transfer belt for conveying a toner image developed on a photoreceptor to a transfer position to a recording medium.

  Cleaning of the intermediate transfer belt made of polyimide having a smooth surface is mainly performed by a blade. Recently, an elastic intermediate transfer belt (elastic ITB) in which a rubber layer or the like is coated on polyimide has been used to improve image quality. The elastic ITB has a rough surface, and the cleaning blade cannot sufficiently scrape the remaining toner. Therefore, cleaning by electrostatic attraction with a fur brush applied with a high pressure is proposed.

JP 2003-066735 A

  However, since the conventional example cannot detect that the cleaning property has deteriorated due to the deterioration of the fur over time, there is a problem that the fur deterioration is not known until the output image deteriorates. Further, since the applied voltage is always constant under the same environment, power may be consumed more than necessary.

  Therefore, in the present invention, the residual toner that has not been completely cleaned is automatically detected, and when the residual toner is generated, the output image quality is improved by controlling the applied voltage of the fur or entering the forced cleaning sequence. It is aimed.

  In order to achieve the above object, the present invention provides one or a plurality of image carriers, an exposure unit for forming a latent image on the image carrier, and a latent image formed by the exposure unit. Developing means, an intermediate transfer belt for conveying the developed toner image to a transfer position to a recording medium, and a primary transfer for transferring the toner image developed on the image carrier to the intermediate transfer belt And an image forming apparatus comprising: a second transfer unit configured to transfer the toner image transferred to the intermediate transfer belt to a recording medium; and for removing toner that has passed through the secondary transfer unit from the intermediate transfer belt. One or a plurality of fur brushes provided in contact with the transfer belt, high voltage generating means for applying a high voltage to the fur brush to electrostatically adsorb toner, and passing through the fur brush. And having a detecting means for detecting the amount of toner, and control means for performing a predetermined control in accordance with the output level of said detection means.

  The present invention also includes one or a plurality of image carriers, an exposure unit for forming a latent image on the image carrier, a developing unit for developing the latent image formed by the exposure unit, An intermediate transfer belt for transporting the developed toner image to a transfer position to a recording medium; a primary transfer means for transferring the toner image developed on the image carrier to the intermediate transfer belt; In an image forming apparatus including a secondary transfer unit for transferring a toner image transferred to a belt to a recording medium, the toner passing through the secondary transfer unit is removed from the intermediate transfer belt so as to come into contact with the transfer belt. One or a plurality of fur brushes provided, a metal roller of the same number as the fur brush provided at a position in contact with the fur brush and not in contact with the transfer belt, and a high voltage is applied to the metal roller. High voltage generating means for electrostatically adsorbing toner by charging the fur brush, detection means for detecting the amount of toner that has passed through the fur brush, and predetermined according to the output level of the detection means And a control means for performing the above control.

  According to the present invention, when a fur brush applied with a high pressure is brought into contact with an elastic ITB having a rough surface and cleaning by electrostatic adsorption is performed, the toner concentration that has not been completely cleaned is detected, and the fur brush or fur brush is detected. By controlling the high voltage applied to the metal roller in contact therewith, it is possible to suppress a decrease in cleaning performance due to the deterioration of fur over time.

  Further, since it is no longer necessary to judge the deterioration of the cleaning fur based on the deterioration of the output image, it is possible to always maintain a high-quality output image.

  Furthermore, since the applied voltage is always reset to the optimum value, power is not consumed more than necessary.

<Embodiment 1>
Hereinafter, a digital copying machine will be described as an example of a preferred embodiment of the present invention.

3 to 6 are drawings showing the configuration of an image forming apparatus according to an embodiment of the present invention. Based on these, a basic configuration will be described.
[Configuration of color reader unit]
FIG. 3 shows the overall configuration of the image forming apparatus, and the upper part of the drawing shows the configuration of the color reader unit.

  Here, 101 is a CCD, 211 is a substrate on which the CCD 101 is mounted, 200 is a control board for controlling the entire image forming apparatus, 201 is a platen glass (platen), 202 is a document feeder (DF) (this (There is also a configuration in which a mirror pressure plate (not shown) is mounted instead of the document feeder 202), 203 and 204 are light sources (halogen lamps or fluorescent lamps) that illuminate the document, and 205 and 206 are light sources 203 and 204 light on the document. A reflecting umbrella for condensing, 207 to 209 are mirrors, 210 is a lens for condensing reflected light or projection light from a document on the CCD 101, and 214 contains halogen lamps 203 and 204, reflecting umbrellas 205 and 206, and a mirror 207. Carriage, 215 is a carriage for accommodating mirrors 208 and 209, 213 is an external interface (I / F) with other devices A.

  The carriage 214 is moved at a speed of V, and the carriage 215 is moved at a speed of V / 2 to mechanically move in the direction perpendicular to the electrical scanning (main scanning) direction of the CCD 101, thereby scanning the entire surface of the document (sub scanning). )

  Further, as shown in FIG. 4, the control board 200 includes a system control unit having an I / F for exchanging information for controlling the digital image processing unit 212, the external I / F 213, and the printer control I / F 253. 301, a memory 303 in the system control unit, and an operation unit 302. The operation unit 302 includes a liquid crystal with a touch panel for inputting processing execution contents by the operator, information about processing for the operator, and notification of warnings and the like.

  The external I / F 213 is an interface for exchanging image information, code information, and the like with the outside of the image processing apparatus. Specifically, as shown in FIG. 5, the facsimile apparatus 401, the LAN interface apparatus 402, and the external A mass storage device 403 or the like can be connected. Note that, for the procedure control of the exchange of image information and code information with the facsimile apparatus 401, the LAN interface apparatus 402, and the external mass storage apparatus 403, the facsimile apparatus 401, the LAN interface apparatus 402, and the external mass storage apparatus that are connection apparatuses. This is performed by mutual communication between the 403 and the system control unit 301 of the control board 200.

  Next, the digital image processing unit 212 will be described in detail. FIG. 6 is a block diagram showing a detailed configuration of the digital image processing unit 212.

  The document on the platen glass reflects light from the light sources 203 and 204, and the reflected light is guided to the CCD 101 and converted into an electrical signal (in the case of a color sensor, the RGB color filter is on one line CCD). It may be in-line in RGB order, or it may be a 3-line CCD with R filters, G filters, and filters arranged for each CCD. The filter is on-chip or the filter is separate from the CCD. Can be used).

  Then, the electric signal (analog image signal) is input to the image processing unit 212, and clamp & Amp. & S / H & A / D unit 102 samples and holds (S / H), clamps the dark level of the analog image signal to the reference potential, and amplifies it to a predetermined amount (the above processing order is not limited to the notation order), and A / D-converted, for example, into RGB 8-bit digital signals. Subsequently, the RGB signal is subjected to shading correction and black correction by the shading unit 103.

  The corrected RGB signal is further connected and MTF corrected & document detection unit 104. When the CCD 101 is a three-line CCD, the connecting process differs in the reading position between lines, so the delay amount for each line is adjusted according to the reading speed. Then, the signal timing correction is performed so that the reading positions of the three lines are the same, and the MTF correction changes the reading MTF depending on the reading speed and the variable magnification. Therefore, the change is corrected, and the document detection unit detects the document on the platen glass. The document size is recognized by scanning.

  The digital signal whose reading position timing is corrected corrects the spectral characteristics of the CCD 101 and the spectral characteristics of the light sources 203 and 204 and the reflectors 205 and 206 by the input masking unit 105. The output of the input masking unit 105 is input to a selector 106 that can be switched to an external I / F signal.

  The signal output from the selector 106 is input to the color space compression & background removal & LOG conversion unit 107 and background removal unit 115. After the background is removed, the signal input to the background removal unit 115 is input to the black character determination unit 116 that determines whether the document is a black character in the document, and generates a black character signal from the document. In the color space compression & background removal & LOG conversion unit 107 to which the output of the other selector 106 is input, the color space compression determines whether or not the read image signal is within a range that can be reproduced by the printer. If not, the image signal is corrected so that it can be reproduced by the printer.

  Then, background removal processing is performed, and RGB signals are converted to CMY signals by LOG conversion. Then, the output signal of the color space compression & background removal & LOG conversion unit 107 is adjusted by the delay 108 in order to correct the signal and timing generated by the black character determination unit 116. The moire removal unit 109 removes moire from these two types of signals, and 110 performs a scaling process in the main scanning direction. Reference numeral 111 denotes a UCR & masking & black character reflecting unit. The CMY signal generated from the magnification processing unit is a CMYK signal generated by the UCR process. The masking processing unit corrects the signal to match the printer output and the black character determination unit. The determination signal generated at 116 is footed back to the CMYK signal.

The signal processed by the UCR & masking & black character reflection unit 111 is subjected to density adjustment by the γ correction unit 112 and then smoothed or edge processed by the filter unit 113. At this time, the correction value of the γ correction unit 112 can be made variable by setting from the system control unit 301, and the density adjustment value can be set for each of CMYK and the density can be set variably. .
[Printer configuration]
Next, the configuration of the printer unit will be described. The lower part of FIG. 3 is a configuration diagram of the main part of a full-color printer which is an example of the image forming apparatus according to the present invention.

  A photosensitive drum (hereinafter simply referred to as “photosensitive member”) 225 as an image carrier is provided so as to be rotated in the direction of arrow A by an image forming motor (not shown). Around the photoconductor 225, a primary charger 221, an exposure device 218, a black development unit 219, a color development unit 223, a primary transfer roller 220, a cleaner device 222, a charge removal device 290, and a potential sensor 291 are arranged.

  The black developing device 219 is a developing device for monochrome development, and develops the latent image on the photoreceptor 225 with K toner. The color developing unit 223 includes three developing devices 223Y, 223M, and 223C for full color development. The developing devices 223Y, 223M, and 223C develop the latent images on the photoreceptor 225 with Y, M, and C toners, respectively. When developing the toner of each color, the developing unit 223 is rotated in the direction of arrow R by a developing device motor (not shown), and the position is adjusted so that the developing device of the color contacts the photoconductor 225.

  The toner images of the respective colors developed on the photosensitive member 225 are sequentially transferred to a belt 226 as an intermediate transfer member by the transfer charger 220, and the four color toner images are superimposed. The belt 226 is stretched around rollers 227, 228 and 229. Among these, the roller 227 is connected to the image forming system motor 023 and functions as a driving roller for driving the belt 226, the roller 228 functions as a tension roller for adjusting the tension of the belt 226, and the roller 229 is a secondary transfer device. Functions as a backup roller for the transfer roller 231.

  The transfer roller attaching / detaching unit 250 is a drive unit for adhering or releasing the transfer roller 231 to / from the belt 226. A belt cleaner 232 is provided at a position facing the roller 227 across the belt 226. The belt cleaner attaching / detaching unit 268 is a drive unit for causing the belt cleaner 232 to adhere to or detach from the belt 226. Residual toner on the belt 226 is cleaned by the belt cleaner detaching unit 268 operating the belt cleaner 232 in the attaching direction.

  The recording media stored in the cassettes 240 and 241 and the manual paper feed unit 253 are illustrated in the nip portion, that is, the contact portion between the secondary transfer device 231 and the belt 226 by the registration roller 255 and the pair of paper feed rollers 235, 236 and 237. The sheet feeding drive motor is used as a drive source. At this time, the secondary transfer device 231 is in contact with the belt 226 by driving the transfer roller attaching / detaching unit 250 in the contact direction. The toner image formed on the belt 226 is transferred onto the recording medium at this nip portion, thermally fixed by the fixing device 234, and discharged outside the device by a fixing drive motor (not shown).

  Note that the cassettes 240 and 241 and the manual sheet feeding unit 253 have sheet-less detection sensors 243, 244, and 245 for detecting the presence or absence of a recording medium, respectively. The cassettes 240 and 241 and the manual paper feed unit 253 have paper feed sensors 247, 248, and 249 for detecting a pickup failure of the recording medium, respectively.

  In the color printer having the above configuration, image formation is performed as follows.

  First, the recording medium conveyance operation in the paper feeding unit will be described.

  The recording media stored in the cassettes 240 and 241 and the manual paper feed unit 253 are conveyed one by one onto the paper feed path by the pickup rollers 238, 239 and 254. When the recording medium on the sheet feeding path is conveyed to the registration roller 255 by the pair of sheet feeding rollers 235, 236, and 237, the registration sensor 256 immediately before that detects the passage of the recording medium.

  In this embodiment, when the registration sensor 256 detects the passage of the recording medium, the conveyance operation is interrupted after an appropriate time has elapsed. As a result, the recording medium abuts on the stopped registration roller 255 and the conveyance is stopped. At this time, the position of the recording medium is fixed so that the traveling direction end of the recording medium is perpendicular to the conveyance path. The paper feed path conveyance direction is corrected when skew occurs due to the deviation of the conveyance direction with respect to the conveyance path. This process is referred to as normal sheet feeding registration. Paper registration is essential for minimizing the inclination of the image forming direction with respect to subsequent recording media. After the paper feed registration is taken, the registration roller 255 is activated to supply the recording medium to the secondary transfer device 231.

  Next, a procedure for forming an image on a recording medium supplied to the secondary transfer device 231 will be described.

  First, a voltage is applied to the charging device 221 to negatively charge the surface of the photoconductor 225 uniformly at a predetermined charging potential. Subsequently, exposure is performed by an exposure device 218 composed of a laser scanner so that the image portion on the charged photoconductor 225 has a predetermined exposure portion potential, and a latent image is formed. The exposure device 218 forms a latent image corresponding to the image by turning on and off based on the image signal.

  A developing bias set in advance for each color is applied to the developing rollers of the black developing device 219 and the color developing device 223, and the latent image is developed with toner when passing through the position of the developing roller to form a toner image. Visualized. The toner image is transferred to the belt 226 by the primary transfer roller 220, further transferred to the recording medium conveyed from the paper feeding unit by the secondary transfer device 231, and then to the fixing device 234 via the fixing conveyance belt 230. It is conveyed.

  First, the fixing device 234 is charged by the pre-fixing chargers 251 and 252 and further the toner image is thermally fixed by the fixing roller 233 in order to compensate for the toner adsorption force and prevent the image disturbance. By 257, the transport path is switched to the paper discharge path 258 side, and the finisher unit 280 is sent. Here, the recording medium which does not require the finishing process of the finisher unit is conveyed as it is in the apparatus and is discharged to the discharge tray 242 as it is.

  In a post-processing step, for example, a mode that requires stapling, the required number of recording media in the finisher unit 280 are stacked and aligned by the aligning unit 281, and the stapling unit 282 performs stapling. After that, it is discharged to the discharge tray 242.

  In full color printing, toners of four colors are superimposed on the belt 226 and then transferred to a recording medium. The toner remaining on the photosensitive member 225 is made to be easily cleaned by a preliminary cleaning device (not shown), removed and collected by the cleaner device 222. Finally, the photosensitive member 225 is uniformly removed by the static eliminator 290. The charge is discharged to around 0 volts to prepare for the next image forming cycle.

  The image forming timing of the color printer is controlled with a predetermined position on the belt 226 as a reference. The belt 226 is wound around rollers including a driving roller 227, a tension roller 228, and a backup roller 229, and a predetermined tension is applied by the tension roller 228.

  Between the driving roller 227 and the roller 228, a reflective sensor 224 that detects the reference position is disposed. The reflective sensor 224 detects a marking such as a reflective tape provided on the inner peripheral surface of the belt 226 and outputs a T-top signal.

  The outer peripheral length of the photosensitive member 225 and the peripheral length of the belt 226 are an integer ratio represented by 1: n (n is an integer). With this setting, the photosensitive member 225 rotates an integer during one rotation of the belt 226 and returns to the same state as before the first rotation of the belt 226. Therefore, four colors are superimposed on the intermediate transfer belt 226. When matching (the belt rotates four times), it is possible to avoid color misregistration due to uneven rotation of the photoconductor 225.

  In the intermediate transfer type image forming apparatus as described above, after detecting the I-top signal, exposure is started by the exposure device 218 including a laser scanner after a predetermined time has elapsed. Further, as described above, the photosensitive member 1 rotates an integer during one revolution of the belt 226 and returns to the same state as before one revolution of the belt, so that a toner image is always formed at the same position on the belt 226. . Although the toner image size changes depending on the paper size, there is a range on the belt 226 where the toner image is never placed.

  Further, in the case of a short paper size image, the belt 226 has a belt length capable of forming a toner image for two images. In particular, two belts 226 are formed to form a color image in which four colors are superimposed. The productivity can be improved by making it possible to form a minute image in a time required for only four belt rotations.

  The operation when an image is formed on the back surface of the recording medium will be described in detail.

  When an image is formed on the back surface of the recording medium, first, image formation on the surface of the recording medium is performed first. Since the image forming operation on the surface has been described in detail above, the description is omitted here. However, in the case of image formation only on the surface, the paper discharge flapper 257 is formed after the toner image is thermally fixed by the fixing device 234 after image formation. As a result, the transport path is switched to the discharge path 258 side, and the sheet is discharged to the discharge tray 235 as it is. Subsequently, when the back side image is formed, the discharge path flapper 257 switches the transport path to the back side path 259 side. The recording medium is once conveyed by a double-sided conveyance motor (not shown) in the double-sided reverse path 261 by the rotational driving of the combined reverse roller 260.

  Thereafter, the recording medium is transported into the duplex reversing path 261 by the width of the recording medium in the feed direction, and then the traveling direction is switched by the duplex reversing path guide 269 by the reverse rotation driving of the reversing roller and the driving of the duplex path transporting roller 262. Then, the image is formed on the surface and conveyed to the duplex path 263 with the image surface facing upward.

  Subsequently, when the recording medium is conveyed on the double-sided path 263 toward the refeed roller 264, the refeed sensor 265 immediately before that detects the passage of the recording medium. In this embodiment, when the passage of the recording medium is detected by the re-feed sensor 265, the transport operation is interrupted after an appropriate time has elapsed. As a result, the recording medium abuts on the stopped re-feed roller 264, and the conveyance is temporarily stopped. At this time, the position of the recording medium is fixed so that the traveling direction end of the recording medium is perpendicular to the conveyance path. Then, the refeed path transport direction correction is performed when skew feeding occurs due to the transport direction of the recording medium deviating from the transport path in the refeed path. This process is generally referred to as re-feed registration.

  The re-feed registration is indispensable for minimizing the inclination of the image forming direction with respect to the back surface of the recording medium thereafter. After re-feeding registration, the re-feed roller 264 is activated to transport the recording medium onto the paper feed path again with the front and back sides reversed. The subsequent image forming operation is the same as the above-described surface image forming operation, and is therefore omitted here. The recording medium on which the image is formed on both the front and back sides is switched as it is by the discharge flapper 257 to the discharge path 258 side, and is discharged to the discharge tray 235 as it is.

  With the operation as described above, in this embodiment, it is possible for the operator to automatically form an image on both sides of the recording medium without resetting the front and back of the recording medium.

  Next, a transfer belt cleaning mechanism using a fur brush characteristic of the present invention will be described.

  FIG. 1 shows a configuration diagram of the transfer belt cleaning mechanism.

  Reference numeral 400 denotes a control unit for controlling the image forming apparatus, 401 denotes an optical reflection type sensor for detecting the residual toner density, and 402 denotes a fur brush for scraping off toner remaining on the transfer belt without being transferred by the secondary transfer. , 403 is a motor for rotating the fur brush, 404 is a high voltage output unit for generating a high voltage potential to apply a high voltage potential to the fur brush, 405 is a desorption motor for detaching the transfer belt cleaner unit from the transfer belt, Reference numeral 406 denotes a display unit for displaying a warning or the like to the user.

  FIG. 2 shows a flow of control performed by the control unit. Start at f101. f102: It is determined whether a predetermined number of sheets (in this embodiment, A4 is equivalent to 50 sheets) has been printed. When 50 sheets are printed, the number counter is reset at f3, and a patch is formed in the non-image area at the next image formation timing: f103. At f104, the residual toner density in the patch portion is sampled. Sampling is performed at 8 points at 8 ms intervals.

  Here, a sampling flow of residual toner density will be described with reference to FIG.

  Control is started at f201. At f202, the LED of the reflective sensor is turned on to prepare for detection. In f203, 0 is substituted for the sampling count value n. In f204, it is determined whether or not the sampling start signal S_ENB that is the output of the control unit 400 is enabled. When S_ENB = '1' and sampling starts, the first sampling is performed at f205 and the data is stored in the predetermined register REG_1. In f206, it is determined whether or not the number of sampling times has reached eight. Since it is still the first time, go to f207 and add 1 to the value of n.

  In f208, it is determined that a predetermined time (8 ms in the present embodiment) has elapsed, and the sampling period is determined. When 8 ms elapses, the process proceeds to f205 and the second sampling is performed. The above operation is repeated 8 times. When n = '7' is determined at f206, the process proceeds to f209, and the maximum and minimum data among the 8 data stored in the register are deleted. This is because erroneous data due to noise or the like is not used. In f210, the remaining 6 data are averaged. In this way, the remaining toner density sampling process is completed.

  Returning to FIG. The average value is used as the residual toner density. f6: It is determined whether the residual toner density is higher than a predetermined level A (a level at which there is residual toner but does not affect the output image). If the residual toner density is lower than level A, the process proceeds to f102. If the residual toner density is higher than level A, it is compared with level B (a level that affects the image) at f106. When the residual toner density is lower than level B, the high pressure set value is increased by one level at f108.

  f108: It is determined whether or not the high pressure set value exceeds a predetermined level. If it exceeds the predetermined level, a message such as “Please replace the transfer cleaning fur brush” is displayed on the display unit 406 at f113. In this case, in order to make it possible to easily replace the fur brush, the desorption motor 405 is driven to be detached from the transfer belt.

  If the high pressure set value does not exceed the predetermined level at f108, it is determined at f109 whether one sheet has been printed. The reason for using one sheet is that when the residual toner exceeds a predetermined amount as described above, the density detection interval is shortened and control is performed so as to eliminate the residual toner as soon as possible. If it is recognized that one sheet has been printed in f109, patch formation is performed in f110, and the process returns to f104. As a result of re-sampling at f104, if there is still residual toner, the high pressure set value is further increased by one level to control to eliminate residual toner.

  When the residual toner density is larger than the predetermined value B at f106, the cleaning sequence is performed at f111. In the cleaning sequence, the transfer belt 226 is continuously rotated and brought into contact with the transfer belt while applying a high pressure to the ITB cleaning fur. Then, when the residual toner density by the residual toner density detection sensor becomes a predetermined value A or less, the process proceeds to f112. At f112, the high pressure level is increased by 2 and the process proceeds to f108.

  By detecting the density of residual toner that has passed through the transfer cleaning fur brush as described above and controlling the voltage applied to the fur brush, even if the fur brush toner recoverability is weakened due to aging, etc. Since it is not necessary to replace the brush, the running cost can be reduced. In addition, image deterioration due to residual toner can be prevented.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIG.

  The transfer cleaning unit 232 includes a first cleaning fur 500, a second cleaning fur 501, a first cleaning roller 502, a second cleaning roller 503, a first cleaning blade 504, and a second cleaning blade 505. ing. The reason why two cleaning furs are used is that, depending on the toner and the device configuration, the polarity of normally positively charged toner may be reversed by secondary transfer, and toner that has both negative and positive polarity must be cleaned. Because it will not be.

  The reason why each of the furs is provided with a metallic cleaning roller is to transfer toner from the fur to the metal roller so that the fur is not soiled. A cleaning blade was installed to scrape off the toner adhering to the metal roller. The output (high polarity is positive) of the high voltage power source 506 is applied to the cleaning roller 502. As a result, the cleaning fur 500 is also positively charged and adsorbs the negative toner. The output (polarity is negative) of the high voltage power supply 404 is applied to the cleaning roller 503. As a result, the cleaning fur 501 is also negatively charged and adsorbs the positive toner. By controlling the cleaning unit configured as described above according to the residual toner level by the residual toner detection sensor 401 as in the first embodiment, the intermediate transfer belt can be cleaned.

1 is a basic configuration diagram of an image forming apparatus according to Embodiment 1 of the present invention. 3 is a basic flowchart of the image forming apparatus according to the first embodiment of the present invention. 1 is a cross-sectional view of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a system configuration diagram of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a configuration diagram of an external interface of an image forming apparatus according to Embodiment 1 of the present invention. 1 is an image processing block diagram of an image forming apparatus according to Embodiment 1 of the present invention. 3 is a sampling flowchart of the image forming apparatus according to the first embodiment of the present invention. It is a basic composition figure of image formation concerning Embodiment 2 of the present invention.

Explanation of symbols

101 CCD
200 Control Board 202 Document Feeder 212 Image Processing Unit 213 External I / F
301 System Control Unit 302 Operation Unit 303 Memory 401 Facsimile Device 402 LAN Interface Device 403 External Mass Storage Device

Claims (20)

One or a plurality of image carriers, an exposure unit for forming a latent image on the image carrier, a developing unit for developing the latent image formed by the exposure unit, and a developed toner image An intermediate transfer belt for conveying the recording medium to a transfer position; a primary transfer means for transferring the toner image developed on the image carrier to the intermediate transfer belt; and a toner transferred to the intermediate transfer belt In an image forming apparatus comprising: a secondary transfer unit for transferring an image to a recording medium;
In order to remove the toner that has passed through the secondary transfer means from the intermediate transfer belt, one or a plurality of fur brushes that are in contact with the transfer belt, and a high voltage is applied to the fur brush to electrostatically attract the toner. A high-pressure generating means for detecting the toner, a detecting means for detecting the amount of toner that has passed through the fur brush, and a control means for performing predetermined control according to the output level of the detecting means. An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein an output voltage of the high voltage generating unit is controlled in accordance with a detection level of the detecting unit.   When it is recognized that the amount of toner that has passed through the fur brush is greater than or equal to a predetermined amount by the detection level of the detection means during normal printing operation, the printing operation is interrupted and the adjustment mode for cleaning the intermediate transfer belt is entered. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus returns to the normal print operation mode when the detection unit recognizes that the amount of toner on the intermediate transfer belt has become a predetermined amount or less.   An adjustment mode for interrupting the printing operation and cleaning the intermediate transfer belt when it is recognized by the detection level of the detection means during the normal printing operation that the amount of toner passing through the fur brush affects the output image. The image forming apparatus according to claim 1, wherein a cleaning sequence is performed for a period corresponding to the detection level to return to a normal print operation mode.   An adjustment mode for interrupting the printing operation and cleaning the intermediate transfer belt when it is recognized by the detection level of the detection means during the normal printing operation that the amount of toner passing through the fur brush affects the output image. , The cleaning sequence is performed, and when the detecting means recognizes that the amount of toner on the intermediate transfer belt has fallen below the predetermined amount, the process returns to the normal printing operation mode, and the subsequent output voltage level of the high voltage generating means is changed. The image forming apparatus according to claim 1.   An adjustment mode for interrupting the printing operation and cleaning the intermediate transfer belt when it is recognized by the detection level of the detection means during the normal printing operation that the amount of toner passing through the fur brush affects the output image. 2. The image forming apparatus according to claim 1, wherein a cleaning sequence is performed in accordance with the detection level, the normal printing operation mode is returned, and the output voltage level of the high-voltage generating unit is changed thereafter.   Display means for conveying information to the user, and a warning is displayed on the display means when the amount of toner passing through the fur brush exceeds a predetermined level according to the detection level of the detection means during a normal printing operation. The image forming apparatus according to claim 1.   It has a display means for conveying information to the user. When the amount of toner passing through the fur brush exceeds a predetermined level according to the detection level of the detection means during a normal printing operation, the fur brush is replaced with the display means. The image forming apparatus according to claim 1, wherein a message to the effect is displayed.   It has a display means for conveying information to the user. When the amount of toner passing through the fur brush exceeds a predetermined level according to the detection level of the detection means during a normal printing operation, the fur brush is replaced with the display means. The image forming apparatus according to claim 1, wherein the attaching / detaching means is controlled so that the fur brush is detached from the intermediate transfer belt for easy replacement.   A patch forming unit for forming a patch image having a predetermined density and a predetermined size outside a normal image forming region. After the cleaning with a fur brush, the detection unit detects a place where the patch is formed on the transfer belt. 10. The image forming apparatus according to claim 1, wherein detection is performed and predetermined control is performed according to the detection level. One or a plurality of image carriers, an exposure unit for forming a latent image on the image carrier, a developing unit for developing the latent image formed by the exposure unit, and a developed toner image An intermediate transfer belt for conveying the recording medium to a transfer position; a primary transfer means for transferring the toner image developed on the image carrier to the intermediate transfer belt; and a toner transferred to the intermediate transfer belt In an image forming apparatus comprising secondary transfer means for transferring an image to a recording medium,
In order to remove the toner that has passed through the secondary transfer means from the intermediate transfer belt, one or more fur brushes that are in contact with the transfer belt and a position that is in contact with the fur brush and not in contact with the transfer belt Further, the same number of metal rollers as the fur brush, high voltage generating means for electrostatically adsorbing the toner by applying a high voltage to the metal roller and charging the fur brush, and the toner passing through the fur brush An image forming apparatus comprising: a detection unit for detecting the amount of the light; and a control unit for performing predetermined control according to an output level of the detection unit.   12. The image forming apparatus according to claim 11, wherein an output voltage of the high voltage generating unit is controlled in accordance with a detection level of the detecting unit.   When it is recognized that the amount of toner that has passed through the fur brush is greater than or equal to a predetermined amount by the detection level of the detection means during normal printing operation, the printing operation is interrupted and the adjustment mode for cleaning the intermediate transfer belt is entered. 12. The image forming apparatus according to claim 11, wherein the image forming apparatus returns to the normal printing operation mode when the detection unit recognizes that the toner on the intermediate transfer belt has become a predetermined amount or less by performing a cleaning sequence.   An adjustment mode for interrupting the printing operation and cleaning the intermediate transfer belt when it is recognized by the detection level of the detection means during the normal printing operation that the amount of toner passing through the fur brush affects the output image. The image forming apparatus according to claim 11, wherein a cleaning sequence is performed in accordance with the detection level, and the normal printing operation mode is restored.   An adjustment mode for interrupting the printing operation and cleaning the intermediate transfer belt when it is recognized by the detection level of the detection means during the normal printing operation that the amount of toner passing through the fur brush affects the output image. , The cleaning sequence is performed, and when the detection unit recognizes that the amount of toner on the intermediate transfer belt has fallen below the predetermined amount, the normal printing operation mode is restored, and the subsequent output voltage level of the high voltage generation unit is changed. The image forming apparatus according to claim 11.   An adjustment mode for interrupting the printing operation and cleaning the intermediate transfer belt when it is recognized by the detection level of the detection means during the normal printing operation that the amount of toner passing through the fur brush affects the output image. The image forming apparatus according to claim 11, wherein a cleaning sequence is performed in accordance with the detection level, the normal printing operation mode is returned, and a subsequent output voltage level of the high voltage generation unit is changed.   Display means for conveying information to the user, and a warning is displayed on the display means when the amount of toner passing through the fur brush exceeds a predetermined level according to the detection level of the detection means during a normal printing operation. The image forming apparatus according to claim 11.   It has a display means for conveying information to the user. When the amount of toner passing through the fur brush exceeds a predetermined level according to the detection level of the detection means during a normal printing operation, the fur brush is replaced with the display means. The image forming apparatus according to claim 11, wherein a message to the effect is displayed.   It has a display means for conveying information to the user. When the amount of toner passing through the fur brush exceeds a predetermined level according to the detection level of the detection means during a normal printing operation, the fur brush is replaced with the display means. The image forming apparatus according to claim 11, wherein the image forming apparatus controls the attaching / detaching means so that the fur brush is detached from the intermediate transfer belt for easy replacement.   A patch forming unit for forming a patch image having a predetermined density and a predetermined size outside a normal image forming region. After the cleaning with a fur brush, the detection unit detects a place where the patch is formed on the transfer belt. The image forming apparatus according to claim 11, wherein detection is performed and predetermined control is performed according to the detection level.

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