JP2005148382A - Toner residual amount detection device and image forming apparatus equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct the toner detecting sensitivity of a toner residual amount sensor. <P>SOLUTION: The toner residual amount sensor 53 is corrected in a period t2 (Figure (c)) that an optical path between the light emitting diode and the phototransistor of the sensor 53 temporarily communicates in the space S2 of a cleaning member 43 in the midst of setting the sensor 53 in a new toner cartridge. Therefore, the toner detecting sensitivity of the sensor 53 is corrected for each of toner cartridges 22a to 22d in the midst of setting the sensor 53. Then, the toner detecting sensitivity of the sensors 53 of respective developing devices 21a to 21d is always corrected and matched, and the residual amount of toner in each of the toner cartridges 22a to 22d is accurately detected by each sensor 53. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner remaining amount detecting device that detects the remaining amount of toner in a toner cartridge in an image forming apparatus such as an electrophotographic system or an electrostatic recording system, and an image forming apparatus including the same.

  As well known, image forming apparatuses such as an electrophotographic system or an electrostatic recording system include a copying machine, a printer, and a facsimile machine. In this type of image forming apparatus, an electrostatic latent image is formed on the photosensitive member, toner is supplied from the developing device to the photosensitive member, and the electrostatic latent image on the photosensitive member is developed with the toner. A toner image is formed thereon, the toner image is transferred from the photosensitive member to a recording sheet, and the recording sheet is heated and pressurized to fix the toner image on the recording sheet.

  In such an image forming apparatus, since the toner is consumed, it is necessary to replenish the toner. For example, a hopper is provided on the developing device, a toner cartridge is detachably mounted on the hopper, the toner is dropped from the toner cartridge to the hopper, and the toner is supplied from the hopper to the developing device.

  Further, the remaining amount of toner in the toner cartridge is detected. When the remaining amount of toner is low, this is displayed to prompt the user to replace the toner cartridge, thereby preventing the interruption of toner supply.

  For example, Patent Document 1 discloses a technique for detecting the remaining amount of toner in a toner cartridge using a remaining toner sensor having a light emitting element and a light receiving element. More specifically, a vertical groove is provided near the bottom of the toner cartridge, and two sets of light-emitting elements and light-receiving elements are arranged opposite to each other with the vertical grooves interposed therebetween. When the toner is sufficient, the toner enters the vertical groove, so that the light from each light emitting element is blocked by the toner and is not received by each light receiving element. Further, when the toner runs out and the toner in the vertical groove runs out, the light from each light emitting element is received by each light receiving element. Therefore, the light receiving output level of each light receiving element is different depending on whether or not the toner is present, and it can be determined that the remaining amount of toner has run out based on the light receiving output level of each light receiving element.

  Further, Patent Document 2 forms an optical path that penetrates the toner cartridge, and a light emitting element and a light receiving element are arranged to face each other through the optical path, and the presence or absence of the remaining amount of toner is determined based on the light reception output level of the light receiving element The technique of determining is disclosed. Here, when there is sufficient toner in the toner cartridge, the light path is blocked by the toner, the light of the light emitting element is not received by the light receiving element, and when there is no toner, the light path passes through the light of the light emitting element. Is received by the light receiving element. Therefore, it is possible to determine the presence or absence of the remaining amount of toner based on the light reception output level of each light receiving element.

Further, in Patent Document 2, when the toner cartridge is attached or detached, the light emitting element and the light receiving element are cleaned by sliding the cleaning member fixed to the toner cartridge to the light emitting element and the light receiving element. This prevents erroneous determination of the remaining amount of toner.
Japanese Patent Application Laid-Open No. 07-56431 Japanese Patent Laid-Open No. 02-240666

  However, neither of the above Patent Documents 1 and 2 does not calibrate the toner detection sensitivity by the light emitting element and the light receiving element, and for this reason, misjudgment of the remaining amount of toner due to variations or fluctuations in the toner detection sensitivity. I was invited.

  For example, in a color image forming apparatus, toners of each color such as cyan, magenta, yellow, and black are used, and a photosensitive member, a developing device, a toner cartridge, and the like are provided for each toner color. It is necessary to detect the remaining amount of toner in the cartridge. For this reason, each toner cartridge is provided with a light emitting element and a light receiving element, and for each toner cartridge, the light emitting element is turned on to detect the light receiving output of the light receiving element, and based on this light receiving output, the remaining amount of toner in the toner cartridge Need to be detected.

  However, if the respective toner detection sensitivities of the light emitting element and the light receiving element of each toner cartridge are different, the determination of the remaining amount of toner in each toner cartridge varies, and these determinations cannot be performed accurately.

  Further, when a scratch or the like occurs on the light emitting surface of the light emitting element or the light incident surface of the light receiving element, the light transmission efficiency between the light emitting element and the light receiving element changes, and the toner detection sensitivity varies. Also in this case, it is impossible to accurately determine the remaining amount of toner in the toner cartridge.

  Accordingly, the present invention has been made in view of the above-described conventional problems, and provides a toner remaining amount detecting device capable of calibrating the toner detection sensitivity of a toner remaining amount sensor and an image forming apparatus including the same. For the purpose.

  In order to solve the above problems, the present invention provides a toner cartridge based on a light reception output of a light receiving element when a light emitting element and a light receiving element of a toner remaining amount sensor are detachably set in the toner cartridge and the light emitting element is turned on. In the toner remaining amount detecting device for detecting the remaining amount of toner, a calibration point through which an optical path between the light emitting element and the light receiving element of the toner remaining amount sensor passes during attachment / detachment of the toner remaining amount sensor, and between the light emitting element and the light receiving element. Sensitivity calibration means for calibrating the toner detection sensitivity of the toner remaining amount sensor so that the light reception output of the light receiving element becomes constant at the timing when the optical path of the toner passes through the calibration location.

  Further, in the present invention, the sensitivity calibration means turns on the light emitting element, and identifies the timing at which the optical path between the light emitting element and the light receiving element passes through the calibration location based on the light reception output of the light receiving element.

  Further, in the present invention, during the attachment / detachment of the toner remaining amount sensor, the light emitting surface and the light incident surface are brought into sliding contact with the light emitting surface on the light emitting element side and the light incident surface on the light receiving element side of the toner remaining amount sensor. A cleaning member for cleaning is provided in the toner cartridge.

  In the present invention, the cleaning member is in sliding contact with the light emitting surface on the light emitting element side and the light incident surface on the light receiving element side of the toner remaining amount sensor, and is frictionally charged to a polarity opposite to the charging polarity of the toner.

  Further, in the present invention, the toner remaining amount sensor is a transmissive type in which a light emitting element and a light receiving element are arranged to face each other, and the calibration location includes a space through which an optical path between the light emitting element and the light receiving element passes.

  In the present invention, the toner remaining amount sensor is a reflective type in which a light emitting element and a light receiving element are arranged in parallel, and the calibration portion has a reflecting surface that reflects and guides light from the light emitting element to the light receiving element. Contains.

  On the other hand, the image forming apparatus of the present invention includes the toner remaining amount detecting device of the present invention.

  According to the present invention, the optical path between the light emitting element and the light receiving element of the toner remaining amount sensor passes through the calibration portion during the attachment / detachment of the toner remaining amount sensor, and the light reception output of the light receiving element is constant at the timing of this passage. Thus, the toner detection sensitivity of the toner remaining amount sensor is calibrated. Accordingly, if each toner remaining amount sensor is assigned to each color toner cartridge as in the color image forming apparatus, the toner detection sensitivity of the remaining toner amount sensor is calibrated for each toner remaining amount sensor when it is attached or detached. Will be. Therefore, it is possible to detect the remaining amount of toner of each color with high accuracy after the toner detection sensitivity of each remaining toner sensor is calibrated and matched. Also, even if the light transmission surface between the light emitting element and the light receiving element changes due to scratches on the light emitting surface of the light emitting element and the light incident surface of the light receiving element, the toner detection sensitivity is calibrated and maintained constant. Therefore, it is possible to always accurately determine the remaining amount of toner in the toner cartridge.

  In addition, since the light emitting element is turned on, and the timing at which the optical path between the light emitting element and the light receiving element passes through the calibration location is identified based on the light reception output of the light receiving element, there is a special case for identifying this timing. There is no need to provide a sensor, a limit switch, or the like, and an increase in the number of parts and cost can be suppressed.

  Further, a cleaning member is provided in the toner cartridge, and the cleaning member is slidably brought into contact with the light emitting surface on the light emitting element side and the light incident surface on the light receiving element side of the toner remaining amount sensor in the middle of attaching / detaching the toner remaining amount sensor. Since the exit surface and the light incident surface are cleaned, it is possible to prevent a decrease in toner detection sensitivity due to contamination of the light exit surface and the light incident surface. Further, by combining the cleaning of the light emitting surface and the light incident surface and the calibration of the toner detection sensitivity, it becomes possible to maintain a constant toner detection sensitivity over a long period of time, thereby improving the reliability.

  Further, since the cleaning member is triboelectrically charged to a polarity opposite to the charging polarity of the toner, the toner easily adheres to the cleaning member, and the toner on the light emitting surface and the light incident surface can be removed well.

  Further, if the toner remaining amount sensor is a transmissive type in which the light emitting element and the light receiving element are arranged to face each other, a space for passing an optical path between the light emitting element and the light receiving element is provided at the calibration location. In this case, at the timing when the optical path between the light emitting element and the light receiving element passes through the calibration point, the light from the light emitting element is directly incident on the light receiving element through the space of the calibration point. The toner detection sensitivity of the toner remaining amount sensor is calibrated so that the output becomes constant.

  If the toner remaining amount sensor is of a reflective type in which a light emitting element and a light receiving element are arranged side by side, a reflection surface that reflects and guides light from the light emitting element to the light receiving element is provided at a calibration location. In this case, at the timing when the optical path between the light emitting element and the light receiving element passes through the calibration part, the light of the light emitting element is reflected by the reflecting surface of the calibration part and then enters the light receiving element. The toner detection sensitivity of the remaining toner sensor is calibrated so that the received light output becomes constant.

  Note that the image forming apparatus of the present invention can achieve the same operations and effects as the toner remaining amount detection apparatus of the present invention.

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

  FIG. 1 is a side view showing Embodiment 1 of the image forming apparatus of the present invention. The image forming apparatus of the present embodiment is a color laser printer that records a color image on a recording sheet, and includes an exposure unit 1, image forming stations Pa, Pb, Pc, Pd, an intermediate transfer belt unit 2, a fixing unit 3, and a sheet. A transport device 4, a paper feed tray 5, a paper discharge tray 6, and the like are provided.

  In this image forming apparatus, the recording paper is stacked and accommodated in the paper feed tray 5, pulled out from the paper feed tray 5 one by one by the pick-up roller 7-1, and transferred to the registration roller 8 by the transport roller 4-1. Be transported. Alternatively, the recording paper is placed on the manual feed tray 9, pulled out by the pickup roller 7-2, and conveyed to the registration roller 8 by the respective conveying rollers 4-4 to 4-6. The registration roller 8 temporarily stops the recording paper, aligns the leading edge of the recording paper, and records at the timing when the leading edge of the recording paper overlaps the leading edge of the toner image formed on the intermediate transfer belt 11 of the intermediate transfer belt unit 2. The sheet is conveyed to the secondary transfer roller 12.

  The image forming stations Pa, Pb, Pc, and Pd respectively form black (K), cyan (C), magenta (M), and yellow (Y) toner images, and transfer the toner images of the respective colors to the intermediate transfer belt unit. 2 is transferred to the intermediate transfer belt 11. These image forming stations Pa, Pb, Pc, and Pd include developing units 21a to 21d, toner cartridges 22a to 22d, photosensitive drums 23a to 23d, charging units 24a to 24d, and cleaner units 25a to 25d. Etc.

  Each of the photosensitive drums 23a to 23d is pressed by the primary transfer rollers 26a to 26d via the intermediate transfer belt 11, and has the same peripheral speed as that of the intermediate transfer belt 11 that rotates and moves in the arrow direction B. It is rotated together with the transfer belt 11. The primary transfer rollers 26 a to 26 d also rotate following the intermediate transfer belt 11 at the same peripheral speed as the intermediate transfer belt 11 that rotates and moves in the arrow direction B.

  Each of the chargers 24a to 24d is of a roller type, a brush type, or a charger type that contacts the photosensitive drums 23a to 23d, and uniformly charges the surfaces of the photosensitive drums 23a to 23d.

  The exposure unit 1 includes a laser light source 1a that emits a laser beam to each of the photosensitive drums 23a to 23d, a plurality of mirrors 1b that guide each laser beam to the respective photosensitive drums 23a to 23d, and the like. Each laser beam is irradiated on the surface of each of the photosensitive drums 23a to 23d while modulating each laser beam according to the image data, thereby forming each electrostatic latent image on the surface of each of the photosensitive drums 23a to 23d. .

  The exposure unit 1 may be a writing head in which light emitting elements such as EL and LED are arranged in an array.

  Each of the toner cartridges 22a to 22d contains black, yellow, magenta, and cyan toners. The developing units 21a to 21d are supplied with the respective color toners from the respective toner cartridges 22a to 22d, and attach the respective color toners to the electrostatic latent images on the surfaces of the respective photoconductive drums 23a to 23d, so The toner images of the respective colors are formed on the surfaces of the body drums 23a to 23d. These toner images are transferred from the photosensitive drums 23a to 23d to the intermediate transfer belt 11 and superimposed.

  The intermediate transfer belt unit 2 includes an intermediate transfer belt 11, primary transfer rollers 26 a to 26 d, a drive support roller 31, a driven support roller 32, a secondary transfer roller 33, and the like. The primary transfer rollers 26 a to 26 d and the secondary transfer roller 33 are pressed against the intermediate transfer belt 11 while being supported by the roller 31 and the driven support roller 32 so as to be rotatable.

  The intermediate transfer belt 11 is formed of a synthetic resin film having a thickness of about 100 μm to 150 μm, for example. The secondary transfer roller 33 is supported so as to be movable left and right. When the secondary transfer roller 33 is moved rightward, the intermediate transfer belt 11 is sandwiched between the secondary transfer roller 33 and the drive support roller 31 to form a nip region. The drive support roller 31 functions as a backup roller for the secondary transfer roller 33, and rotates with the respective nip areas between the primary transfer rollers 26a to 26d and the photosensitive drums 23a to 23d downstream. When driven, the intermediate transfer belt 11 is pulled and rotated in the arrow direction B. Thereby, each nip area is stably maintained.

  In order to more stably form the nip areas between the primary transfer rollers 26a to 26d and the photosensitive drums 23a to 23d, the primary transfer rollers 26a to 26d and the photosensitive drums 23a to 23d are formed. Preferably, one of them is made of a hard material and the other is made of an elastic material.

  Each of the primary transfer rollers 26a to 26d is formed, for example, by coating the outer periphery of a metal shaft having a diameter of 8 mm to 10 mm with a conductive elastic material (EPDM, urethane foam, or the like). The primary transfer rollers 26a to 26d are opposite in polarity to the toner charging polarity in a state where the intermediate transfer belt 11 is sandwiched between nip regions between the primary transfer rollers 26a to 26d and the photosensitive drums 23a to 23d. Are applied to the toner on the surfaces of the photosensitive drums 23a to 23d via the intermediate transfer belt 11, and the toner on the surfaces of the photosensitive drums 23a to 23d is attracted to the intermediate transfer belt 11. To transcribe. As a result, the toner images of the respective colors are transferred to the intermediate transfer belt 11 and superimposed.

  In addition, as each primary transfer roller 26a-26d, you may use a brush etc. instead of a roller.

  The cleaning unit 34 is, for example, a cleaning blade that is in sliding contact with the surface of the intermediate transfer belt 11 and removes toner remaining on the surface of the intermediate transfer belt 11 to prevent fogging of an image to be printed next time.

  The toner images of the respective colors transferred and superimposed on the intermediate transfer belt 11 in this way are conveyed to the nip area between the drive support roller 31 and the secondary transfer roller 33 as the intermediate transfer belt 11 rotates. Then, the leading edge of each color toner image on the intermediate transfer belt 11 and the leading edge of the recording sheet conveyed by the registration roller 8 are overlapped, and the toner image of each color and the recording sheet are overlapped to form the toner image of each color. Transferred onto recording paper.

  Subsequently, the recording paper is conveyed to the fixing unit 3, where it is sandwiched between the pressure roller 3a and the heating roller 3b. As a result, the toner of each color on the recording paper is mixed with a heating margin, and the toner image of each color is fixed on the recording paper as a color image.

  Further, the recording paper is transported to the paper discharge tray 6 by the paper transport device 4, and is discharged face down here.

  Note that it is also possible to form a monochrome image using only the image forming station Pa and transfer the monochrome image to the intermediate transfer belt 11 of the intermediate transfer belt unit 2. Similarly to the color image, this monochrome image is also transferred from the intermediate transfer belt 11 to the recording paper and fixed on the recording paper.

  When printing on both sides of the recording paper as well as on the recording paper, the recording paper is conveyed by the conveying roller 4-3 of the paper conveying device 4 after fixing the image on the surface of the recording paper by the fixing unit 3. Then, the conveying roller 4-3 is stopped and then reversely rotated, the recording sheet is passed through the reversing path 4r of the sheet conveying apparatus 4, the recording sheet is reversed, and the recording sheet is guided to the registration roller 8. Similarly to the front surface of the recording paper, an image is recorded and fixed on the back surface of the recording paper, and the recording paper is discharged to the paper discharge tray 6.

  By the way, in the image forming apparatus of the present embodiment, as shown in FIG. 2, the toner cartridges 22a to 22d can be detached from the developing devices 21a to 21d, and the toner cartridges 22a to 22d are replaced with new ones. Thus, toner of each color is replenished.

  Next, each of the toner cartridges 22a to 22d will be described in detail. FIG. 3 shows a state before the toner cartridge 22 (the common symbol of each of the toner cartridges 22a to 22d is 22) is attached to the developing device 21 (the common symbol of each of the developing devices 21a to 21d is 21). FIG. FIG. 4 is a perspective view showing the toner cartridge 22 and the developing device 21 before being mounted as viewed from the back side. Further, FIG. 5 is a perspective view showing the toner cartridge 22 and the developing device 21 after being mounted as viewed from the back side. FIG. 6 is a longitudinal sectional view showing the toner cartridge 22 and the developing device 21 before being installed as viewed from the side, and FIG. 7 is a view showing the toner cartridge 22 and the developing device 21 after being installed as viewed from the side. It is a longitudinal cross-sectional view. 8 is an enlarged sectional view of the mounted toner cartridge 22 and the developing device 21 as viewed from the front side, and FIG. 9 is an enlarged perspective view of the developing device 21 as viewed from the front side. It is.

  Although the depth t of the toner cartridge 22 is sufficiently shorter than the depth T of the developing device 21, the height h is sufficiently increased to secure the volume. Since the depth t of the toner cartridge 22 is shortened, the toner cartridge 22 does not interfere with the components at the back of the image forming apparatus when the toner cartridge 22 is mounted near the front surface of the image forming apparatus.

  As shown in FIG. 8, the toner cartridge 22 has a toner supply port 22f at the bottom and a flange 22g around the toner supply port 22f. Further, the developing device 21 has a toner receiving port 21f on the top plate and guide grooves 21g on both sides of the toner receiving port 21f. As shown in FIG. 9, a guide plate 41 is inserted into each guide groove 21g. The guide plate 41 is urged by a spring (not shown) toward the front of the image forming apparatus (in the arrow direction C) so that one end 41a of the guide plate 41 is brought into contact with the edge of the toner receiving port 21f. Is closed.

  When the toner cartridge 22 is mounted, the toner cartridge 22 is placed on the top plate of the developing device 21, the flange 22 g of the toner cartridge 22 is inserted into the guide groove 21 g of the developing device 21, and the toner cartridge 22 is placed at the back of the image forming apparatus. The guide plate 41 is pushed by the flange 22g of the toner cartridge 22 to open the guide plate 41, and the toner supply port 22f of the toner cartridge 22 and the toner receiving port 21f of the developing device 21 are slid in the direction (arrow D in FIG. 3). Are superimposed. Thereafter, as shown in FIG. 7, the two-fold seal 42 that seals the toner supply port 22f of the toner cartridge 22 is pulled off and removed, and the toner supply port 22f of the toner cartridge 22 and the toner reception of the developing device 21 are received. The toner can be supplied from the toner cartridge 22 to the developing device 21 through the opening 21f.

  When the toner in the toner cartridge 22 runs out, the toner cartridge 22 is slid toward the front of the image forming apparatus and removed.

  Thus, the toner cartridge 22 is mounted and removed, and the replacement is performed.

  Further, an upper recess 22 i and a lower recess 22 j are formed on the side wall of the toner cartridge 22, and a cleaning member 43 protrudes between the upper recess 22 i and the lower recess 22 j. Inside the toner cartridge 22, an upper concave portion 22i and a lower concave portion 22j protrude inward, a transparent plate 44 is attached to the lower surface of the upper concave portion 22i, a transparent plate 45 is attached to the upper surface of the lower concave portion 22j, and each transparent plate 44, 45 are arranged opposite to each other, and a space S <b> 1 is provided between the transparent plates 44 and 45.

  FIGS. 10A and 10B are a plan view and a side view showing the cleaning member 43. As is clear from FIGS. 10A and 10B, the cleaning member 43 has a pair of support pieces 43b protruding from the side wall of the toner cartridge 22 and supports the elastic pieces 43a by the support pieces 43b. A space S <b> 2 is provided between the elastic piece 43 a and the side wall of the toner cartridge 22.

  Further, in the toner cartridge 22, the driven shaft 46 is rotatably supported by a pair of bearings 47, and the stirring member 48 is fixedly supported on the driven shaft 46. One end of the driven shaft 46 protrudes from the side wall of the toner cartridge 22, and a cross groove 46a is formed on the end surface thereof. The agitating member 48 is obtained by combining the rods 48a in a substantially rectangular shape and fixing them together. One of the rods 48a parallel to the driven shaft 46 protrudes to the vicinity of the side wall of the toner cartridge 22, and a flexible film piece 49 is attached to one end of the rod 48a. As shown in an enlarged view in FIG. 11, a slit 48b is formed at one end of the rod body 48a, and a flexible film piece 49 is inserted into the slit 48b and fixed with an adhesive. The flexible film piece 49 is perpendicularly crossed with respect to a certain cylindrical peripheral surface.

  When the driven shaft 46 rotates, the stirring member 48 rotates, and the toner in the toner cartridge 22 is stirred. As the stirring member 48 rotates, the flexible film piece 49 also rotates. At this time, as shown in FIG. 12, the rod 48a protruding to the vicinity of the side wall of the toner cartridge 22 passes through the space S1 between the transparent plates 44 and 45 in the middle of its rotation, and the flexible film piece 49 also has the space S1. Pass through.

  On the other hand, a cartridge driving unit 51 is provided on the developing device 21. In the cartridge drive unit 51, the drive shaft 52 is pivotally supported, and the cross-shaped tip 52a of the drive shaft 52 is projected toward the front side of the image forming apparatus. The drive shaft 52 is rotationally driven by a motor and gear unit (not shown). A toner remaining amount sensor 53 is attached to the side wall of the cartridge drive unit 51.

  The toner remaining amount sensor 53 includes a base portion 54, a light emitting portion 55, and a light receiving portion 56 fixed to the side wall of the cartridge driving portion 51. The light emitting portion 55 and the light receiving portion 56 project from the base portion 54 and face each other. doing. The light emitting unit 55 includes a light emitting diode 57 and emits light from the light emitting diode 57 to the light receiving unit 56. The light receiving unit 56 includes a phototransistor 58, and the light from the light emitting diode 57 is received by the phototransistor 58.

  As described above, the toner cartridge 22 is mounted on the top plate of the developing device 21 by sliding toward the back of the image forming apparatus, and the toner supply port 22f of the toner cartridge 22 and the toner receiving port 21f of the developing device 21 are mounted. Are overlapped with the cross groove 46a of the driven shaft 46 of the toner cartridge 22, and the drive shaft 52 and the driven shaft 46 are connected to each other. In addition, the light emitting portion 55 and the light receiving portion 56 of the toner remaining amount sensor 53 are fitted in the upper concave portion 22 i and the lower concave portion 22 j of the toner cartridge 22.

  When the cruciform tip 52 a of the drive shaft 52 and the cross groove 46 a of the driven shaft 46 are fitted, the drive shaft 52 and the driven shaft 46 are connected, and the rotation of the drive shaft 52 is transmitted to the driven shaft 46. Therefore, when the drive shaft 52 of the cartridge drive unit 51 is driven to rotate, the driven shaft 46 of the toner cartridge 22 rotates and the stirring member 48 also rotates. The toner in the toner cartridge 22 is stirred by the rotation of the stirring member 48, and the flexible film piece 49 is also rotated to periodically pass through the space S1 between the transparent plates 44 and 45.

  When the light emitting portion 55 and the light receiving portion 56 of the toner remaining amount sensor 53 are fitted in the upper concave portion 22 i and the lower concave portion 22 j of the toner cartridge 22, the light emitting diode 57 of the light emitting portion 55 and the phototransistor 58 of the light receiving portion 56 are connected. The transparent plate 44 of the upper concave portion 22i, the transparent plate 45 of the lower concave portion 22j, and the space S1 are opposed to each other.

  As described above, when the toner cartridge 22 is mounted on the top plate of the developing device 21 and is slid toward the back of the image forming apparatus, the remaining amount of toner as shown in FIGS. The light emitting surface of the light emitting unit 55 and the light incident surface of the light receiving unit 56 of the sensor 53 are in sliding contact with the elastic piece 43a of the cleaning member 43, and the dirt on the light emitting surface and the light incident surface is scraped off by the elastic piece 43a. It is. For this reason, the detection of toner by the light emitting unit 55 and the light receiving unit 56 described later is not hindered by the contamination of the light emitting surface of the light emitting unit 55 and the light incident surface of the light receiving unit 56.

  Since the light emitting surface of the light emitting portion 55 of the toner remaining amount sensor 53 and the light incident surface of the light receiving portion 56 are in sliding contact with the elastic piece 43 a of the cleaning member 43, the light emitting surface of the light emitting portion 55 and the light incident surface of the light receiving portion 56. The elastic piece 43a is frictionally charged. If the light emitting surface of the light emitting unit 55 and the light incident surface of the light receiving unit 56 are charged with a polarity opposite to that of the toner, the toner easily adheres to the light emitting surface and the light incident surface. If the light incident surface of the light receiving unit 56 is charged with the same polarity as the toner, the toner is less likely to adhere to the light emitting surface and the light incident surface. Further, if the elastic piece 43a of the cleaning member 43 is charged with a polarity opposite to that of the toner, the toner easily adheres to the elastic piece 43a, and the toner on the light emitting surface and the light incident surface is well removed, and cleaning is performed on the contrary. If the elastic piece 43a of the member 43 is charged with the same polarity as the toner, the toner is difficult to adhere to the elastic piece 43a. For this reason, as the material of the light emitting surface of the light emitting unit 55, the light incident surface of the light receiving unit 56, and the elastic piece 43a, the light emitting surface and the light incident surface are frictionally charged to the same polarity as the toner, and the elastic piece 43a Select one that is triboelectrically charged to the opposite polarity.

  Here, as shown in FIG. 14A, when the toner in the toner cartridge 22 is sufficient and the space S1 between the transparent plates 44 and 45 is filled with toner, the light emitting diode 57 of the light emitting section 55 The light is shielded by the toner in the space S1, and this light is not received by the phototransistor 58 of the light receiving unit 56. Further, the flexible film piece 49 rotates together with the stirring member 48, enters the toner, advances through the toner, bends on both sides of the rod body 48a, and is substantially folded in half. Therefore, the flexible film piece 49 does not come into contact with the transparent plates 44 and 45 when passing through the space S1 between the transparent plates 44 and 45.

  As shown in FIG. 14B, when the toner in the toner cartridge 22 decreases and the toner level is between the transparent plates 44 and 45, the lower transparent plate 44 is covered with the toner. The light of the light emitting diode 57 of the light emitting unit 55 is shielded by the toner in the space S1, and this light is not received by the phototransistor 58 of the light receiving unit 56. Further, when the flexible film piece 49 passes through the space S1 between the transparent plates 44 and 45, the flexible film piece 49 bends on both sides of the rod body 48a, the lower edge leveles the toner, and the upper edge is the upper side. The surface of the transparent plate 44 is slidably contacted and the toner on the surface is scraped off.

  Further, as shown in FIG. 14C, when the toner in the toner cartridge 22 is further reduced and the toner level becomes lower than the transparent plate 45 on the lower side, the toner in the space S1 disappears, and the light emitting unit 55 The light from the light emitting diode 57 passes through the transparent plates 44 and 45, and this light is received by the phototransistor 58 of the light receiving unit 56. Further, when the flexible film piece 49 passes through the space S1 between the transparent plates 44 and 45, the flexible film piece 49 bends on both sides of the rod body 48a, and both side edges thereof are in sliding contact with the surfaces of the transparent plates 44 and 45, respectively. Scratch off the toner on each surface. For this reason, the light of the light emitting diode 57 of the light emitting section 55 is not shielded by the dirt on the surfaces of the transparent plates 44 and 45, and the light of the light emitting diode 57 is reliably received by the phototransistor 58. In addition, although the toner remaining slightly by the rotation of the stirring member 49 is stirred and the toner is splashed upward and falls downward, the toner dropped near the transparent plates 44 and 45 is contained in the toner cartridge 22. The surface of the transparent plates 44 and 45 is not soiled by the dropped toner because it is caught by the upwardly projecting upper concave portion 22i. In other words, the upper recess 22 i serves as a roof that prevents the toner from falling on the transparent plates 44 and 45.

  Since the flexible film piece 49 is in sliding contact with the surfaces of the transparent plates 44 and 45, the flexible film piece 49 and the transparent plates 44 and 45 are frictionally charged. If each of the transparent plates 44 and 45 is charged with a polarity opposite to that of the toner, the toner easily adheres to each of the transparent plates 44 and 45. Conversely, if each of the transparent plates 44 and 45 is charged with the same polarity as that of the toner, The toner hardly adheres to the plates 44 and 45. For this reason, as the material of the flexible film piece 49 and each of the transparent plates 44 and 45, a material such that each of the transparent plates 44 and 45 is frictionally charged to the same polarity as the toner is selected. As a material of the flexible film piece 49, for example, polyethylene terephthalate, polyimide, polyamide or the like is flexible. Therefore, the material of each transparent plate 44, 45 needs to be set according to the material of the flexible film piece 49. Or, conversely, after determining the material of each transparent plate 44, 45, the material of the flexible film piece 49 may be set according to the material of each transparent plate 44, 45.

  As described above, when the toner level in the toner cartridge 22 exceeds the lower transparent plate 45, the light reception level of the phototransistor 58 is extremely low. When the toner level is lower than the lower transparent plate 45, the phototransistor 58 The light reception level increases. Therefore, based on the light reception output level of the phototransistor 58, it can be determined whether or not the remaining amount of toner in the toner cartridge 22 has decreased.

  When the toner level in the toner cartridge 22 is lower than the lower transparent plate 45, the surface of each transparent plate 44, 45 is scraped off by the flexible film piece 49, and the upper recess 22i is formed on each transparent plate. 44 and 45, the toner is prevented from falling on the transparent plates 44 and 45, so that the light from the light-emitting diodes 57 of the light-emitting portion 55 is blocked by dirt on the surfaces of the transparent plates 44 and 45. Therefore, the remaining toner amount can be reliably detected by the remaining toner sensor 53.

  By the way, if the lead wires of the light emitting diode 57 and the phototransistor 58 are provided for each of the toner remaining amount sensors 53 of the developing devices 21a to 21d, the wiring becomes complicated. Therefore, in this embodiment, as shown in FIG. 15, each of the remaining toner amount sensors 53 is connected to suppress complicated wiring.

  FIG. 15 is a block diagram illustrating a toner remaining amount detection device in the image forming apparatus according to the present exemplary embodiment. In this toner remaining amount detecting device, the light emitting diode 57a and the phototransistor 58a, the light emitting diode 57b and the phototransistor 58b, the light emitting diode 57c and the phototransistor 58c, and the light emitting diode 57d and the phototransistor 58d are respectively connected to the toner cartridges 22a, 22b, 22c, Each of the remaining toner sensors 53 detects the remaining toner amount 22d.

  The controller 61 drives and controls each of the light emitting diodes 57a to 57d separately, inputs the light reception output of each phototransistor 58a to 58d via a wired OR, and based on the light reception output level of each phototransistor 58a to 58d, The remaining amount of toner in each of the toner cartridges 22a to 22d is detected. Further, the control unit 61 adjusts the drive current of each of the light emitting diodes 57a to 57d and adjusts the load resistance of each of the phototransistors 58a to 58d, thereby calibrating the toner detection sensitivity of each toner remaining amount sensor 53. Match. This calibration compensates for variations in the characteristics of the light emitting diodes 57a to 57d and the phototransistors 58a to 58d, and light between the light emitting diode and the phototransistor due to scratches on the light emitting surface of the light emitting diode and the light incident surface of the phototransistor. This is performed in order to compensate for a decrease in transmission efficiency and prevent a decrease in detection accuracy of the remaining amount of toner.

  Here, the light emitting diodes 57a to 57d and the transistors 62a to 62d are associated with each other and connected in series. The anodes of the light emitting diodes 57a to 57d are commonly connected by a line 63, the emitters of the transistors 62a to 62d are commonly connected, and the bases of the transistors 62a to 62d are connected to the control unit 61 through the lines 64a to 64d. It is connected to each terminal Sy, Sm, Sc, Sk. The control unit 61 selects and turns on any of the transistors 62a to 62d through the lines 64a to 64d. When any one of the transistors 62a to 62d is selected and turned on, a series circuit of the selected transistor and a light emitting diode corresponding to the transistor is turned on.

  The control unit 61 generates a rectangular wave output having a duty ratio corresponding to a prescribed driving current, and outputs the rectangular wave output from the terminal PWM to the smoothing circuit 65. The smoothing circuit 65 includes resistors, capacitors, and a first operational amplifier 66, smoothes the rectangular wave output, and outputs an average voltage of the rectangular wave output to the second operational amplifier 67. The second operational amplifier 67 inputs the voltage from the smoothing circuit 65 to the non-inverting input terminal, and inputs the current from the series circuit of the selected transistor and the light-emitting diode to the inverting input terminal. The difference between the voltage at the input terminal and the voltage at the inverting input terminal is output. As a result, a specified drive current corresponding to the duty ratio of the rectangular wave output from the terminal PWM of the control unit 61 flows in the series circuit of the selected transistor and the light emitting diode, and the light emitting diode is driven to the specified drive. Light is emitted at a light intensity corresponding to the current. That is, when a rectangular wave output is output from the terminal PWM of the control unit 61, an average voltage of the rectangular wave output is generated by the smoothing circuit 65, and this voltage is subjected to voltage-current conversion by the second operational amplifier 67. A specified drive current corresponding to the duty ratio of the rectangular wave output is generated, the specified drive current flows through the series circuit of the selected transistor and the light emitting diode, and the light emitting diode corresponds to the specified drive current Emits light with the intensity of light. Therefore, the light intensity of the light emitting diode can be controlled by adjusting the duty ratio of the rectangular wave output from the terminal PWM.

  Further, the emitters of the phototransistors 58a to 58d are wired-or connected by a line 68, the resistors 71a to 71d and the transistors 72a to 72d are associated with each other in series, and the resistors 71a to 71d are connected to the line 68. The emitters of the transistors 72a to 72d are grounded, and the bases of the transistors 72a to 72d are connected to the terminals G0, G1, G2, and G3 of the control unit 61 through the lines 73a to 73d.

  The controller 61 selectively turns on 0 to 4 of the transistors 72a to 72d through the lines 73a to 73d. Thereby, 0 to 4 of the resistors 71a to 71d are selectively inserted between the line 68 and the ground, and the resistance value between the line 68 and the ground is adjusted and set, so that each of the phototransistors 58a to 58d is adjusted. A resistive load is set. For example, the ratio of the resistance values R3, R2, R1, and R0 of the resistors 71a to 71d is set to 8: 4: 2: 1, and 0 to 4 of the resistors 71a to 71d are selectively inserted. To adjust the resistance between line 68 and ground.

  In such a circuit configuration, the control unit 61 selects and turns on any of the transistors 62a to 62d while outputting the specified drive current through the smoothing circuit 65 and the second operational amplifier 67 as described above. Then, a driving current is supplied to the series circuit of the selected and turned on transistor and the light emitting diode, and the light emitting diode of one toner remaining amount sensor 53 is caused to emit light. At this time, if there is sufficient toner remaining in the toner cartridge in which the toner remaining amount sensor 53 is set, the phototransistor of the toner remaining amount sensor 53 does not receive light, and there is no remaining toner in the toner cartridge. In this case, the phototransistor of the toner remaining amount sensor 53 receives light. The controller 61 monitors the light reception output by inputting the light reception output of the phototransistor of the toner remaining amount sensor 53 to the terminal A / D via the wired OR of the line 68, and based on the light reception output level. Thus, it is determined whether or not the remaining amount of toner in the toner cartridge has decreased.

  At this time, the control unit 61 calibrates the toner detection sensitivity for each toner remaining amount sensor 53 based on the calibration data table D as shown in FIG. The toner remaining amount is determined. This calibration is the adjustment of the drive currents of the respective light emitting diodes 57a to 57d and the load resistances of the respective phototransistors 58a to 58d as described above, whereby the toner detection sensitivity of each remaining toner sensor 53 is adjusted. Is calibrated to match. More specifically, the control unit 61 obtains a duty ratio corresponding to the drive current of the light emitting diode of the toner remaining amount sensor 53 based on the calibration data table D, and generates and outputs a rectangular wave output of this duty ratio. As a result, the drive current is passed through the light emitting diode through the smoothing circuit 65 and the second operational amplifier 67. At the same time, the control unit 61 selects 0 to 4 of the transistors 72a to 72d based on the calibration data table D, and selects the selected one of the transistors 72a to 72d through the lines 73a to 73d. Turned on and sets the resistance load of the phototransistor of the toner remaining amount sensor 53. As a result, it is possible to accurately determine the remaining toner amount of each of the toner cartridges 22a to 22d by each remaining toner sensor 53 without variation.

  Further, the control unit 61 repeats the detection by the same toner remaining amount sensor 53 a predetermined number of times in a predetermined cycle, obtains each detection result, extracts a plurality of detection results that are the same, and detects different detection results. Based on the plurality of detection results that are the same, it is determined whether or not the remaining amount of toner in the toner cartridge has decreased. For example, as shown in the graph of FIG. 17, when the rotation period of the flexible film 49 that rotates together with the stirring member 48 is T and the detection period by the toner remaining amount sensor 53 is Ts, Ts = 7T / 6 is set. , The detection by the toner remaining amount sensor 53 is repeated 6 times at a fixed period of 7T, and 5 detection results of the same soot are extracted, one different detection result is removed, and the same 5 times are detected. Based on the detection result, it is determined whether or not the remaining amount of toner in the toner cartridge has decreased. Alternatively, Ts = 7T / 8 is set, and the detection by the toner remaining amount sensor 53 is repeated 8 times at a constant period of 7T, and 7 detection results of the same soot are extracted, and one different detection result is obtained. Based on the same seven detection results, it is determined whether or not the remaining amount of toner in the toner cartridge has decreased.

  This is because when the flexible film 49 passes through the space S1 between the transparent plates 44 and 45, the light path between the light emitting diode and the phototransistor of the toner remaining amount sensor 53 is blocked by the flexible film 49, Since it becomes difficult to detect the remaining amount of toner by the remaining amount sensor 53, the rotation period T of the flexible film 49 and the detection period Ts by the remaining toner sensor 53 are slightly shifted so that the flexible film 49 has the space S1. The number of detections of the toner remaining amount sensor 53 performed when the toner does not pass through the toner is increased, and the number of detections of the toner remaining amount sensor 53 performed when the flexible film 49 passes the space S1 is decreased. In the above, by extracting a plurality of detection results that are the same and removing one different detection result, the flexible film 49 has a space S. In order to obtain only the detection result when non passed the. This makes it possible to accurately determine the remaining amount of toner.

  Such a determination is repeatedly performed every time the remaining toner sensors 53 of the developing devices 21a to 21d are sequentially selected. If it is determined that there is no remaining toner in any of the toner cartridges 22a to 22d, the toner cartridge having no remaining toner is displayed on a display unit (not shown), or a voice message is displayed on a speaker (FIG. (Not shown) to prompt replacement of the toner cartridge, thereby preventing interruption of toner supply.

  Next, the calibration data table D in FIG. 16 will be described in detail. First, the calibration data table D is initialized when the image forming apparatus is shipped from the factory. This is to compensate for variations in the characteristics of the light emitting diode and the phototransistor of each toner remaining amount sensor 53.

  For example, the control unit 61 sequentially selects the toner remaining amount sensors 53 of the developing devices 21a to 21d in a state where the toner cartridges 22a to 22d are removed, and selects each time the toner remaining amount sensor 53 is selected. The driving current is supplied to the light emitting diode of the toner remaining amount sensor 53, and the light receiving output of the phototransistor of the toner remaining amount sensor 53 is input, and the driving current is changed by changing the duty ratio of the rectangular wave output. The resistance load of the phototransistor of the toner remaining amount sensor 53 is changed by turning on and off 72a to 72d to adjust the light reception output level of the phototransistor to a specified value. Then, the rectangular wave output duty ratio and the ON / OFF state of each of the transistors 72a to 72d when the light receiving output level reaches a specified value are obtained, and the duty ratio of these rectangular wave output and the ON / OFF state of each of the transistors 72a to 72d are determined. Store in the calibration data table D. Thus, for each toner remaining amount sensor 53 of each developing device 21a to 21d, the duty ratio of the rectangular wave output for calibrating and matching the toner detection sensitivity and the on / off state of each of the transistors 72a to 72d are displayed in the calibration data table D. Remembered.

  Further, the calibration data table D is updated every time the toner cartridge is replaced after being purchased by the user. This compensates for a decrease in light transmission efficiency between the light emitting diode and the phototransistor due to scratches on the light emitting surface of the light emitting diode of the toner remaining amount sensor 53 and the light incident surface of the phototransistor, and decreases the detection accuracy of the remaining amount of toner. It is for preventing.

  For example, if the controller 61 determines that the toner cartridge 22a has no remaining toner based on the light reception output level of the toner remaining amount sensor 53 of the developing device 21a, the controller 61 displays the toner cartridge 22a having no remaining toner as a display unit ( (Not shown) or a voice message is generated by a speaker (not shown) to prompt the user to replace the toner cartridge. At this time, in order to replace the toner cartridge 22a, the user needs to follow the procedure of opening the front door of the image forming apparatus, removing the toner cartridge 22a, and mounting a new toner cartridge 22a on the developing device 21a. Therefore, when the opening of the front door of the image forming apparatus is detected by a limit switch (not shown), the control unit 61 considers that the toner cartridge 22a determined to have no remaining toner is replaced, and the developing device. While continuously emitting the light emitting diode of the toner remaining amount sensor 53 of 21a, the light reception output of the phototransistor of the toner remaining amount sensor 53 is continuously monitored.

  By removing the toner cartridge 22a, the toner remaining amount sensor 53 is also removed from the toner cartridge 22a. At the time of removal, the optical path between the light emitting diode and the phototransistor of the toner remaining amount sensor 53 is a space S1 between the transparent plates 44 and 45 as shown in FIGS. 13D, 13C, 13B, and 13A. , And once blocked by the side wall 22e of the toner cartridge 22a, re-connects in the space S2 of the cleaning member 43, is further blocked by the elastic piece 43a of the cleaning member 43, and continues thereafter outside the image forming apparatus. Accordingly, the light reception output of the phototransistor of the toner remaining amount sensor 53 changes to high level, low level, high level, low level, and high level as shown in FIG. Therefore, when the control unit 61 detects the change pattern in FIG. 18A regarding the light reception output of the phototransistor of the toner remaining amount sensor 53 being monitored, the control unit 61 considers that the toner cartridge 22a has been removed.

  Subsequently, when a new toner cartridge 22a is mounted, the toner remaining amount sensor 53 is set in the toner cartridge 22a. At this time, the optical path between the light emitting diode of the toner remaining amount sensor 53 and the phototransistor communicates outside the image forming apparatus as shown in FIGS. 13A, 13B, 13D, and 13D. It is blocked by the elastic piece 43a, is once passed through the space S2 of the cleaning member 43, is blocked by the side wall 22e of the toner cartridge 22a, and is also blocked by the space S1 between the transparent plates 44 and 45. Accordingly, the light receiving output of the phototransistor of the toner remaining amount sensor 53 changes to high level, low level, high level, and low level as shown in FIG. Therefore, when the control unit 61 detects the first low-level period t1 in FIG. 18B after the toner cartridge 22a is removed, it is assumed that the installation of a new toner cartridge 22a is started. In the next high level period t2, the monitoring of the remaining toner sensor 53 is performed. In this calibration, the duty ratio of the rectangular wave output corresponding to the driving current of the light emitting diode of the toner remaining amount sensor 53 being monitored is changed, and the phototransistors of the toner remaining amount sensor 53 are turned on and off by the transistors 72a to 72d. The resistance load is changed to adjust the light reception output level of the phototransistor to a specified value, and the duty ratio of the rectangular wave output and the on / off states of the transistors 72a to 72d when this light reception output level reaches the specified value are obtained. The duty ratio of these rectangular wave outputs and the on / off states of the transistors 72a to 72d are stored in the calibration data table D.

  Note that not only the toner cartridge 22a but also the other toner cartridges 22b to 22d are detected when the remaining amount of toner in the toner cartridge is detected and the front door of the image forming apparatus is opened. When the toner cartridge is attached or detached, the remaining toner sensor is calibrated.

  Further, although the removal of the toner cartridge is detected based on the change pattern of the light reception output of the toner remaining amount sensor 53 shown in FIG. 18A, a special case for detecting the removal of the toner cartridge for each toner cartridge. A sensor or a limit switch may be provided. In this case, regardless of whether it is determined that there is no toner remaining, the light emitting diode of the toner remaining amount sensor 53 of the developing device in which the toner cartridge is mounted is detected after the removal of the toner cartridge is detected. While continuously emitting light, the light reception output of the phototransistor of the toner remaining amount sensor 53 may be continuously monitored, and the toner remaining amount sensor may be calibrated during the period t2 when the toner cartridge is mounted.

  As described above, in this embodiment, the toner remaining amount sensor 53 is being set in a new toner cartridge, and the light path between the light emitting diode and the phototransistor of the remaining toner amount sensor 53 is temporarily in the space S2 of the cleaning member 43. The remaining toner sensor 53 is calibrated during the communication period t2 (FIG. 13C). Therefore, the toner detection sensitivity of the remaining toner sensor 53 is calibrated while the remaining toner sensor 53 is being set for each of the toner cartridges 22a to 22d. For this reason, the toner detection sensitivities of the toner remaining amount sensors 53 of the developing devices 21a to 21d can always be calibrated and matched, and the toner remaining amounts of the toner cartridges 22a to 22d can be accurately adjusted by the toner remaining amount sensors 53. Can be detected. Also, even if the light emitting surface of the light emitting diode or the light incident surface of the phototransistor is scratched and the light transmission efficiency between the light emitting diode and the phototransistor changes, the toner detection sensitivity is calibrated and maintained constant. Therefore, it is possible to always accurately determine the remaining amount of toner in the toner cartridge.

  Further, immediately after the period t1 (FIG. 13B) in which the optical path between the light emitting diode and the phototransistor of the toner remaining amount sensor 53 is blocked by the elastic piece 43a of the cleaning member 43, accordingly, the toner remaining amount sensor 53 is removed by the cleaning member 43. Immediately after the toner on the light emitting surface of the light emitting portion 55 and the light incident surface of the light receiving portion 56 are scraped off, the remaining toner sensor 53 is calibrated. For this reason, this calibration can be performed accurately without being affected by the contamination of the toner on the light emitting surface and the light incident surface. Further, by combining the cleaning of the light emitting surface and the light incident surface and the calibration of the toner detection sensitivity, it becomes possible to maintain a constant toner detection sensitivity over a long period of time, thereby improving the reliability.

  In addition, this invention is not limited to the said Example, It can deform | transform variously. For example, instead of storing the duty ratio of the rectangular wave output and the ON / OFF states of the transistors 72a to 72d when the light receiving output level of the phototransistor reaches a specified value for each toner remaining amount sensor 53 in the calibration data table D, The light reception output of the phototransistor when the duty ratio of the rectangular wave output is kept constant and the load of the phototransistor is kept constant may be stored in the calibration data table D. In this case, based on the light reception output level of the phototransistor in the calibration data table D, the duty ratio of the rectangular wave output and the load of the phototransistor are set so that the light reception output of the phototransistor becomes a predetermined value. Become.

  Instead of changing the driving current of the light emitting diode of the toner remaining amount sensor 53 and changing the resistance load of the phototransistor of the toner remaining amount sensor 53 to calibrate the toner detection sensitivity of the toner remaining amount sensor 53, For each toner remaining amount sensor 53, the toner detection sensitivity of the remaining toner amount sensor 53 may be calibrated by changing a reference value to be compared with the light receiving output of the phototransistor for determining the remaining toner amount.

  Further, as the toner remaining amount sensor 53, a transmissive type in which the light emitting diode 57 and the phototransistor 58 are arranged to face each other is illustrated, but instead, the light emitting diode 57 as shown in FIGS. 19 (a) and 19 (b). Alternatively, a reflection type in which the light-emitting diode 57 and the phototransistor 58 are arranged in parallel with the white plate 59 via the transparent plates 44 and 45 and the space S1 may be applied.

  In this reflective toner remaining amount sensor 53A, a light beam from the light emitting diode 57 is reflected by the white plate 59, and a reciprocating optical path is formed in which the reflected light enters the phototransistor 58. When the toner is in the space S1, When the reciprocating optical path is blocked and the phototransistor 58 does not receive light and no toner is in the space S1, the reciprocating optical path passes and the phototransistor 58 receives light. Therefore, based on the light reception output level of the phototransistor 58, it can be determined whether or not the remaining amount of toner in the toner cartridge 22 is exhausted.

  In addition, when the reflective toner remaining amount sensor 53A is used, a cleaning member 43A in which a white plate 43c is provided between the support pieces 43b is applied as shown in FIG. In the middle of setting the toner remaining amount sensor 53A in the new toner cartridge, the white plate 43c of the cleaning member 43A faces the light emitting diode 57 and the phototransistor 58 of the toner remaining amount sensor 53A, and the light of the light emitting diode 57 is white plate 43c. A reciprocating optical path is formed in which the reflected light is incident on the phototransistor 58, and the remaining toner sensor 53 is calibrated during the period in which the reciprocating optical path is formed.

1 is a side view showing Embodiment 1 of an image forming apparatus of the present invention. FIG. 2 is a side view showing a state where each toner cartridge is removed from the image forming apparatus of FIG. 1. FIG. 3 is a perspective view showing a state before the toner cartridge is mounted on the developing device as seen from the front side. FIG. 3 is a perspective view showing a toner cartridge and a developing device before being mounted as viewed from the back side. FIG. 3 is a perspective view showing the toner cartridge and the developing device after being mounted as viewed from the back side. FIG. 3 is a vertical cross-sectional view showing a toner cartridge and a developing device before being mounted as viewed from the side. FIG. 3 is a longitudinal sectional view showing the toner cartridge and the developing device after being mounted as viewed from the side. FIG. 3 is an enlarged cross-sectional view of the mounted toner cartridge and the developing device when viewed from the front side. It is a perspective view which expands and shows a developing device seeing from the front side. (A) And (b) is the top view and side view which show the cleaning member of a toner cartridge. FIG. 3 is an enlarged front view showing a flexible film piece attached to a stirring member of a toner cartridge. FIG. 4 is a front view showing a state where a flexible film piece passes through a space between transparent plates as the stirring member of the toner cartridge is stirred. (A)-(d) is a front view which shows a mode that the light emission surface of the light emission part of a toner remaining amount sensor, and the light-incidence surface of a light-receiving part of a toner remaining amount sensor are cleaned by the cleaning member of a toner cartridge, when a toner cartridge is attached or detached. . (A)-(c) is the front view used in order to demonstrate the detection of the toner remaining amount in the toner cartridge by a toner remaining amount sensor. 3 is a block diagram illustrating a toner remaining amount detection device in the image forming apparatus according to the present exemplary embodiment. FIG. FIG. 6 is a conceptual diagram showing a calibration data table D used for calibration of a toner remaining amount sensor. 4 is a graph showing a rotation period T of a flexible film that rotates with a stirring member of a toner cartridge and a detection period Ts by a toner remaining amount sensor. (A) And (b) is a graph which shows the change of the detection output of the toner remaining amount sensor at the time of attachment or detachment of a toner cartridge. (A) And (b) is the front view and side view which show the other example of a toner remaining amount sensor. FIG. 20 is a plan view showing a cleaning member for cleaning the toner remaining amount sensor of FIG. 19.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exposure unit 2 Intermediate transfer belt unit 3 Fixing unit 4 Paper conveyance device 5 Paper feed tray 6 Paper discharge tray 21, 21a-21d Developer 22, 22, 22a-22d Toner cartridge 53 Toner remaining amount sensor 57 Light emitting diode 58 Phototransistor Pa, Pb, Pc, Pd Image forming station

Claims (7)

A toner remaining amount detecting device that sets a light emitting element and a light receiving element of a toner remaining amount sensor detachably in a toner cartridge, and detects a toner remaining amount of the toner cartridge based on a light receiving output of the light receiving element when the light emitting element is turned on. In
A calibration point through which the optical path between the light emitting element and the light receiving element of the toner remaining amount sensor passes in the middle of attachment / detachment of the toner remaining amount sensor,
Sensitivity calibration means for calibrating the toner detection sensitivity of the remaining toner sensor so that the light reception output of the light receiving element is constant at the timing when the optical path between the light emitting element and the light receiving element passes through the calibration point. Toner remaining amount detecting device.   The sensitivity calibration means turns on the light emitting element and identifies the timing at which the optical path between the light emitting element and the light receiving element passes through the calibration location based on the light reception output of the light receiving element. Toner remaining amount detection device.   A toner cartridge that cleans the light emitting surface and the light incident surface by slidingly contacting the light emitting surface on the light emitting element side and the light incident surface on the light receiving element side of the toner remaining amount sensor in the middle of attachment / detachment of the toner remaining amount sensor. The toner remaining amount detecting device according to claim 1, wherein the toner remaining amount detecting device is provided.   4. The cleaning member according to claim 3, wherein the cleaning member is in sliding contact with the light emitting surface on the light emitting element side and the light incident surface on the light receiving element side of the toner remaining amount sensor, and is frictionally charged to a polarity opposite to the charging polarity of the toner. The toner remaining amount detecting device. The toner remaining amount sensor is a transmission type in which a light emitting element and a light receiving element are arranged to face each other.
The toner remaining amount detection apparatus according to claim 1, wherein the calibration portion includes a space through which an optical path between the light emitting element and the light receiving element passes. The toner remaining amount sensor is a reflective type in which a light emitting element and a light receiving element are arranged in parallel.
The residual toner amount detecting device according to claim 1, wherein the calibration portion includes a reflection surface that reflects and guides light from the light emitting element to the light receiving element. An image forming apparatus comprising the toner remaining amount detecting device according to claim 1.

Images