JP2006208444A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably output an image of high quality and to realize reduction of power consumption by appropriate collection of scattered toner. <P>SOLUTION: The scattered toner floating inside an apparatus is detected by using a scattered toner detection sensor 60 and a collection fan is controlled according to the amount of the scattered toner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile.

  In image formation by an electrophotographic process, an electrostatic latent image is formed on a photoreceptor, and the electrostatic latent image is developed and visualized with a developer (toner) in a developing device, and the obtained toner image is transferred onto a transfer paper. A desired image is obtained by transferring the image to the image.

However, when a very large number of images are copied by the above-described process, the toner in the developing device may be scattered in the apparatus due to deterioration of the developer or environmental fluctuation. In this case, contamination occurs in a wide range of devices such as optical systems such as mirrors and lenses in the machine, image forming process elements such as various chargers and developing devices, and paper feeding and conveying systems. As a result, deterioration of development characteristics, deterioration of image quality, and erroneous detection and malfunction due to adhesion to the sensor are caused. In order to prevent such a problem, it has been proposed to detect the scattered toner and control the operation of the developing device so that the toner can be prevented from scattering. (See Patent Document 1)
Japanese Patent Registration No. 3140329

  However, in addition to the conventional developer deterioration, environmental fluctuations, and toner scattering due to control system troubles, the deterioration of the developer has rapidly increased due to the smaller toner particles and higher productivity associated with the recent increase in image quality. As a result, the cause of toner scattering in the machine is increasing, and the conventional method for preventing toner scattering in the image forming apparatus cannot sufficiently cope with it.

  Also, in an image forming apparatus that collects scattered toner using a conventional exhaust fan, exhaust is not performed with an air volume corresponding to the floating toner in the machine. There is a problem that wasteful power is consumed because the fan is uniformly driven even when the contamination occurs and the amount of scattered toner is small or no exhaust is required.

  Therefore, an object of the present invention is to solve at least one of such problems and other problems. Other issues can be understood throughout the specification.

  In order to solve the above problems, an image forming apparatus according to claim 1 of the present invention records a toner image formed by developing a latent image on a latent image carrier with a developer on a recording material. In the image forming apparatus for forming the image forming apparatus, the image forming apparatus includes an exhaust unit having a fan for collecting dust generated in the apparatus, and a detection unit for detecting the dust, and according to a detection result of the detection unit. An image forming apparatus comprising control means for controlling the exhaust means.

  In this way, an exhaust fan that exhausts the air inside the machine to the outside of the machine is provided, the scattered toner floating inside the device is detected by the sensor, and the air volume of the exhaust fan is changed, thereby reducing the image quality due to the scattered toner and the sensor It is possible to prevent erroneous detection and malfunction due to toner adhesion on the surface.

  According to the present invention, by exhausting with an air volume corresponding to the toner floating in the machine, it is possible to stably output high-quality images by preventing contamination in the machine due to scattered toner, and optimal fan control The purpose is to save power.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of an image forming apparatus to which the present invention is applied. The image forming apparatus is mounted on a main body image output unit 10 that is a device that outputs a document image on a recording sheet, a main body image input unit 11 that is a device that reads image data from a document, and an upper part of the main body image input unit 11. The automatic document feeder 12 and a sorter 13 for sorting and ejecting copy recording media ejected from the main body image output unit 10 into a plurality of bins.

  This image forming apparatus is a digital copying machine, and is converted into pixels by a CCD of a main body image input unit 11 which is an apparatus for reading image data from a document, read into the apparatus as image data, and after necessary image processing is performed, the image is processed. Stored in memory. The image data is transferred to the main body image output unit 10, and the image is reproduced and copied onto a recording sheet.

  The main body image input unit 11 includes a light source 21 that performs scanning while irradiating a document placed on a document table on the upper surface of the input unit. The light source 21 obtains a driving force from an optical system motor (not shown) and reciprocates in the left-right direction in FIG. The light generated from the light source 21 is reflected by the stacked originals to obtain an optical image. The optical image is transmitted to the CCD 26 via the mirrors 22, 23 and 24 and the lens 25. The mirrors 22, 23, and 24 are driven integrally with the light source 21. The CCD 26 is composed of an element that converts light into an electrical signal. An optical image transmitted by the function of this element is converted into an electrical signal, and further converted into a digital signal (image data). The read image data of the original is subjected to various correction processes and image processes desired by the user, and is stored in an image memory (not shown).

  The main body image output unit 10 reads the image data stored in the image memory, reconverts the digital signal into an analog signal, and further amplifies the output value to an appropriate output value by an exposure control unit (not shown). Converted to a signal.

  FIG. 2 is an enlarged view around the photosensitive drum 31. A primary charger 44, a developing device 45, a transfer charger 46, a separation charger 47, and a cleaning device 48 are arranged around the photosensitive drum 31 in order according to the rotation direction. After the surface of the photosensitive drum 31 is uniformly charged by the primary charger 44, the optical signal propagates through the scanner 28, the lens 29, and the mirror 30, and is irradiated onto the photosensitive drum 31, thereby causing an electrostatic latent image. Is formed. The developed image is developed by the developing unit 45, and the developed image is transferred onto a recording sheet conveyed through the main body by a transfer charging unit 46 to form a document image. The toner remaining on the surface of the photosensitive drum 31 to which the developed image has been transferred is removed by the cleaning device 48. The separation charger 47 separates the recording paper on which the image is transferred from the photosensitive drum 31. The separated recording paper is further conveyed to the fixing roller 32, and the toner is fixed on the recording medium by the fixing roller and is sent to the sorter 13.

  The sorter 13 is a device installed on the left side of the main body image output unit 10, and performs a process of sorting the recording paper output from the main body image output unit 10 into the discharge tray 33 and discharging the recording paper. The paper discharge tray is controlled by the main body control unit (not shown), and the output recording paper is discharged to an arbitrary paper discharge tray instructed by the control unit.

  The paper feed trays 34 and 35 are located at the lower part of the main body, and can store recording paper to some extent. Under the control of the main body control unit, the recording paper accumulated from the paper feed trays 34 and 35 is conveyed to output an image. The paper feed deck 36 is a device installed on the left side of the main body image output unit 10 and can store a large amount of recording paper. As with the paper feed trays 34 and 35, the recording paper accumulated under the control of the main body control unit is conveyed and an image is output.

  A manual feed tray 37 is provided on the left side of the main body image output unit 10 so that an operator can relatively easily feed a small number of arbitrary types of copy recording media. The manual feed tray is also used when a special recording medium such as an OHP sheet, cardboard, or postcard size paper is used.

  The rollers 38, 39, 40, 41, and 42 are paper transport rollers, and each roller plays a role of actually transporting the recording paper when feeding a copy output process. Each paper feed roller is connected to a stepping motor as a drive source via a transmission device such as a gear.

  The dust collection fan 49 is for collecting the toner floating in the apparatus. A dust collection filter (not shown) is attached to the dust collection fan 49, and the dust collection fan 49 is driven to scatter the toner. To collect dust. The scattered toner detection sensor 60 detects the amount of toner floating inside the apparatus. The dust collection fan 49 is driven and controlled according to the detected amount of scattered toner, and the scattered toner is adsorbed to the dust collection filter. To do.

  In this embodiment, the dust collecting fan 49 and the scattered toner detection sensor 60 are arranged on the upper portion of the developing device 45, so that the toner scattered from the developing device 45 is not shown around the optical mirror 30 and the photosensitive drum 31 in the vicinity. The sensor is not contaminated.

  However, the arrangement of the dust collecting fan 49 and the scattered toner detection sensor 60 is not limited to this. For example, the dust collecting fan 49 and the scattered toner detection sensor 60 are arranged near the lower part of the developing unit 45 or in the vicinity of the transfer charging unit 46 and the separation charging unit 47. It is also possible to prevent the recording paper from becoming dirty due to the scattered toner adhering to the conveyance path for conveying the recording paper.

  FIG. 3 is a block diagram of a main control system of the main body image output unit 10. The CPU unit 301 manages the fixing control unit 302, the high voltage control unit 303, the paper conveyance control unit 304, and the laser driving unit 305 based on information from the sensor input unit 306. The fixing control unit 302 controls the fixing device 32. The high voltage control unit 303 controls each of the primary charger 44, the transfer charger 46, and the separation charger 47. The laser drive unit 305 performs light amount control for image formation based on the image data transmitted from the controller. A sensor input unit 306 takes in an input of a sensor provided on a paper conveyance path, a lever, a cover, a cassette, or the like into the CPU unit 301 and determines an image forming state such as an operating state or a paper out state. The paper transport control unit 304 manages the position of the paper transported based on information from the sensor input unit 306 and performs paper transport control. The motor control unit 307 performs drive control of various paper transport rollers according to the paper transport control. Further, the cassette (34, 35 and 36 in FIG. 1) is provided with a sensor for detecting the paper size to be replenished, and these sensor inputs are also taken into the CPU unit 301 to measure the set paper size. . The interface unit 310 is connected to a printer interface of an external controller (not shown), communicates with the controller, and is an input unit of image data from the controller.

  The scattering detection sensor control unit 306 controls the scattering toner detection sensor 60 that is a part of the sensor input unit to detect the scattering toner floating in the apparatus. The dust collection fan control unit 311 controls the dust collection fan 49 to adsorb the scattered toner in the apparatus to the dust collection filter.

  A scattering toner detection method by the scattering detection sensor control unit 506 and a dust collection method of the scattering toner by the dust collection fan control unit 311 according to the detected amount of scattering toner will be described with reference to FIGS. 4, 5, and 6. .

  FIG. 4 is a block diagram of the scattering detection sensor control unit 306 and the dust collection fan control unit 311.

  The timing signal generation circuit 402 in the scattering detection sensor control unit 306 is an LED that turns on the light emitting element 403 of the scattering toner detection sensor 60 using an optical sensor based on the set value of the CPU 301 by the clock input from the transmission circuit 401. A pulse signal 411 is generated. The signal processing circuit 405 detects an output signal corresponding to the amount of scattered toner detected by the light receiving element 404 in synchronization with the LED light emission pulse signal 411 of the light emitting element 403, and compares it with a predetermined threshold value to compare the amount of scattered toner. The sensor output signal 413 corresponding to is processed and output to the CPU 301. The driver 407 generates a drive voltage 414 for controlling the rotational drive of the dust collection fan 49 from the PWM signal 416 that is the drive signal of the dust collection fan 49 from the CPU 301.

  5 and 6 are timing charts of various signals generated by the scattering detection sensor control unit 306 and the dust collection fan control unit 311. FIG.

  FIG. 5 corresponds to a case where the amount of toner scattered in the apparatus is large, and FIG. 6 illustrates a case where the amount of toner is small compared to the state of scattering in FIG.

  As described above, the CPU 301 detects the toner scattering amount by measuring the sensor output signal 413 detected by the scattering detection sensor control unit 306 at a predetermined time interval, and outputs the fan PWM signal 416 according to the value. The dust collecting fan control unit 311 outputs the driving voltage 414 to control the dust collecting fan.

  FIG. 7 is a flowchart of dust collection fan control by toner scattering amount detection using the scattering detection sensor of the present invention.

  First, when dust collection fan control by toner scattering amount detection is started (S701), the scattering detection sensor is controlled, and a sensor output signal 613 corresponding to toner scattering data is passed at a predetermined sampling period for a predetermined time. (S702, S703). Next, after a predetermined time elapses, the measured scattering data is averaged to calculate the amount of scattered toner (S705). When the amount of scattered toner is in the range of 80% to 100% of the assumed amount of scattering, the supply voltage of the dust collecting fan is set to 24V and the fan is driven (S709). In this case, a fan having an air volume that can be sufficiently exhausted at a voltage of 24 V is selected in advance even when toner with an estimated scattering amount of 100% is generated. When the scattering amount is in the range of 41% to 79%, the supply voltage of the dust collecting fan is set to 19V and the fan is driven (S710). Similarly, the scattering amount is in the range of 1% to 40%. Sets the supply voltage of the dust collecting fan to 10 V and drives the fan (S711). If the scattering amount is 0% and there is no scattering, the supply voltage of the dust collecting fan is set to 0 V and the fan is stopped (S712).

  By repeatedly executing the dust collection fan control based on the detection of the amount of scattered toner, the scattered toner in the apparatus can always be exhausted with an optimum air volume.

1 is a configuration diagram of an embodiment to which an image forming apparatus of the present invention is applied. 1 is an enlarged configuration diagram around a photosensitive drum of an embodiment to which an image forming apparatus of the present invention is applied. 3 is a block diagram of a main control system of the image forming apparatus of the present invention. FIG. 2 is a block diagram of a scattering detection sensor control unit 306 and a dust collection fan control unit 311 of the image forming apparatus of the present invention. FIG. 7 is a timing chart when the amount of scattered toner in the generation signals of the scattering detection sensor control unit 306 and the dust collection fan control unit 311 of the present invention is large. 6 is a timing chart when the amount of scattered toner in the generated signals of the scattering detection sensor control unit 306 and the dust collection fan control unit 311 of the present invention is small. 6 is a flowchart of dust collection fan control based on toner scattering amount detection in the image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Main body image output part 49 Dust collection fan 60 Scatter toner detection sensor 306 Sensor input part 311 Dust collection fan control part

Claims (6)

In an image forming apparatus for recording a toner image formed by developing a latent image on a latent image carrier with a developer on a recording material to form an image,
Control means having exhaust means for collecting dust generated in the apparatus and a fan for collecting dust and detection means for detecting the dust, and controlling the exhaust means according to the detection result of the detection means An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the detection unit detects a dust amount, and the control unit controls a rotation speed of the fan according to the detected dust amount.   The image forming apparatus according to claim 2, wherein the control unit can control the fan at a plurality of rotation speeds according to the detected amount of dust.   The image forming apparatus according to claim 2, wherein the control unit controls a supply voltage supplied to the fan in accordance with the detected amount of dust.   The image forming apparatus according to claim 1, wherein the detecting unit includes a light emitting unit that irradiates light to the dust, and a light receiving unit that detects light applied to the dust by a light receiving element and detects a dust amount. . The image forming apparatus according to claim 1, wherein the exhaust unit includes a member for adsorbing dust generated in the apparatus.

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