JP2008033171A - Toner storage container, developing device and image forming apparatus having them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately control an amount of toner supplied to the developing tank of a developing device. <P>SOLUTION: The toner storage container 1 that supplies toner to the developing tank 12 has, in its lower surface, a plurality of toner supply ports 26 for use in the supply of toner to the developing tank 12. One to be used for supplying toner to the developing tank 12 is selected from the plurality of toner supply ports 26 for changing according to a rate at which images are printed. Thus, the supply of toner to the developing tank 12 can be finely controlled taking account of the amount of toner consumption determined according as whether the rate at which images are printed is high or low. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner storage container, a developing device, and an image forming apparatus including the same, which are used in an image forming apparatus such as an electrophotographic copying machine, a facsimile machine, or a printer.

  In general, an electrophotographic image forming apparatus forms an electrostatic latent image on an image carrier such as a photosensitive roller in the apparatus. Then, the image forming apparatus develops the electrostatic latent image by flying toner used as a developer from a developing roller or the like to an image carrier, and transfers the image onto a transfer material such as paper and fixes the image on a fixing device. Form.

  The method for developing the electrostatic latent image on the image carrier is specifically as follows. First, the developing device charges the toner by stirring or the like in a developing tank provided in the developing device. Next, the developing roller holds the charged toner on its outer peripheral surface and forms a thin layer of toner. Then, by applying a predetermined voltage to the developing roller, the toner on the developing roller is caused to fly to the image carrier. In this way, the electrostatic latent image is developed.

  The toner consumed for image formation as described above is supplied to the developing tank of the developing device as needed. In general, as a toner replenishing method, a toner container or a toner cartridge called a toner container is provided in a developing device, and toner is replenished from the toner container to the developing tank. This is because the user only needs to replace the toner storage container, which is advantageous in terms of member cost, disposal cost, recyclability, and the like, compared with the case of replacing a process unit in which a so-called image carrier is integrated. Because.

  Here, the amount of toner replenished from the toner container to the developing tank of the developing device affects the quality of the formed image. For example, if the amount of toner replenished to the developing tank is too large, a large amount of toner that is not used for development remains in the developing tank and continues to be stirred in the developing tank, and the toner thin layer on the developing roller is made uniform. Due to the restriction member, it is stressed several times. As a result, the fluidity of the toner is impaired and the toner deteriorates. Since such toner has poor fluidity, it causes toner to adhere to a portion where the toner should not be developed in image formation (so-called fogging).

  Furthermore, the detection accuracy of the detection means for detecting the amount of toner in the developing tank is lowered due to a decrease in toner fluidity. As a result, although the amount of toner in the developing tank is sufficient, the detection unit may erroneously detect that the toner is insufficient. Due to this erroneous detection, the detection means issues a signal to cause the toner to further flow into the developing tank even though the amount of toner in the developing tank is sufficient. That is, the toner is supplied to the developing tank more than necessary.

  Then, the excessively replenished toner is deteriorated without being used for development. Furthermore, a vicious cycle may occur in which the detection unit makes a false detection again and toner is replenished excessively again. On the other hand, if the amount of toner in the developing tank is too small, the toner thin layer formed on the developing roller is thinned, and the density of the formed image is lowered.

Patent Document 1 has been proposed as an invention for controlling toner supply from a toner container to a developing tank. In Patent Document 1, when toner is replenished to a toner receiving port provided in a developing housing from two toner replenishing ports provided in a toner storage container, all of the toner is initially filled at the time of initial filling because the toner is initially charged at high speed. There is described a toner container that replenishes toner using only one toner replenishing port during normal operation in which toner is replenished and image formation is performed.
JP-A-2005-43523

  Thus, controlling the replenishment of toner to the developing tank of the developing device is an important factor in image formation. However, although the timing and amount of toner replenishment are conventionally determined by the detection means provided in the developing tank, as described above, the accuracy of the detection means is reduced due to a decrease in fluidity due to toner deterioration. There is a problem that is not supported.

  Further, in general, the developing device is provided with only one toner receiving port having a predetermined length for allowing toner to flow into the developing tank. When toner is replenished, the toner is allowed to flow all at once. However, such a replenishment method has a problem that it is difficult to appropriately control the toner replenishment amount.

  Note that the invention described in Patent Document 1 is intended to increase the initial filling speed when the image forming apparatus is used for the first time, and cannot solve the above-described problems.

  The present invention has been made in view of the above-described problems of the prior art, and provides and forms a developing device and a toner storage container that can appropriately control the amount and timing of toner supply to the developing tank of the developing device. It is an object of the present invention to provide an image forming apparatus capable of maintaining high image quality.

  In order to achieve the above object, the invention according to claim 1 is a toner storage container for supplying toner to a developing tank for circulating toner provided in the developing device, and supplying toner for supplying toner to the developing tank. A plurality of ports are provided on the lower surface, and among the plurality of toner replenishing ports, the toner replenishing port used for replenishing toner to the developing tank is changed depending on the image printing rate.

  According to a second aspect of the present invention, in the first aspect of the present invention, a toner shutter for controlling the outflow of toner is provided in the toner storage container in the vicinity of the toner replenishing port. A plurality of openings for allowing the toner to flow out are provided in the cylindrical shape, and the toner flows out from the toner supply port when the opening and the toner supply port face each other. The toner supply port through which the toner flows out is changed by rotating the toner shutter in the circumferential direction so that the opening and the toner supply port are opposed to each other.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the toner replenishing port used for replenishing toner to the developing tank is provided in the developing tank as the image printing rate increases. From the detection means for detecting the toner amount in the developer tank, the toner supply port that is farthest upstream in the toner circulation direction in the developing tank is changed from the furthest toner supply port that is closest to the detection means. .

  According to a fourth aspect of the present invention, in the developing device having a developing tank for circulating the toner, the developing tank is provided with a plurality of toner inlets for replenishing toner, and the plurality of toner inlets are provided. The toner receiving port used for supplying toner to the developing tank is changed depending on the image printing rate.

  According to a fifth aspect of the present invention, in the fourth aspect of the invention, the developing tank is provided with detecting means for detecting the amount of toner in the developing tank, and the image printing rate is increased. Accordingly, the toner receiving port used for supplying toner to the developing tank is changed from the farthest toner receiving port on the upstream side in the toner circulation direction to the nearest toner receiving port as viewed from the detecting means. did.

  According to a sixth aspect of the present invention, in the image forming apparatus, the toner container according to the first to third aspects and the developing device according to the fourth or fifth aspect are provided.

  According to the first aspect of the present invention, in the toner storage container for supplying toner to the developing tank for circulating the toner provided in the developing device, a plurality of toner supply ports for supplying toner to the developing tank are provided on the lower surface. Since the toner replenishing port used for replenishing toner to the developing tank among the plurality of toner replenishing ports is changed depending on the image printing rate, the amount of toner consumed due to the level of the image printing rate is taken into consideration. The toner supply to the developing tank can be finely controlled.

  According to a second aspect of the present invention, in the first aspect of the present invention, a toner shutter for controlling the outflow of toner is provided in the toner storage container in the vicinity of the toner supply port, and the toner shutter has a cylindrical shape. A plurality of openings are provided to allow the toner to flow out. The openings are configured such that when the opening and the toner supply port face each other, the toner flows out from the toner supply port. By rotating the toner shutter in the circumferential direction so that the toner replenishing port is opposed to the toner replenishing port, the toner replenishing port from which the toner flows out is changed, so that the toner outflow can be reliably controlled by the toner shutter. Further, it is simpler and more compact than providing a mechanism for selecting a toner supply port to be used outside the toner storage container.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the toner replenishing port used for replenishing toner to the developing tank has a toner in the developing tank provided in the developing tank as the image printing rate increases. In view of the detection means for detecting the amount, since the toner supply port farthest upstream in the toner circulation direction in the developing tank is changed from the toner supply port closest to the detection means, the image printing rate is high. When a large amount of toner is consumed, if the toner flows out from the toner replenishing port close to the detecting means in the developing tank, the detecting means can detect the toner replenishment in a short time, and the toner is more than necessary. The developer tank is not replenished.

  On the other hand, when the image printing rate is low and the amount of toner consumption is small, for example, by letting out the toner little by little from the toner replenishing port far from the detecting means in the developing tank, the detecting means is long until it detects toner replenishment. Although it takes time, the remaining toner in the developing tank and the new toner can be sufficiently mixed, and the quality of image formation is improved.

  According to a fourth aspect of the present invention, in the developing device having a developing tank for circulating the toner, the developing tank is provided with a plurality of toner inlets for replenishing toner, and the plurality of toner inlets are provided. The toner receiving port used for replenishing toner to the developing tank is changed depending on the image printing rate, so that the amount of toner flowing into the developing tank takes into account the amount of toner consumed due to the level of the image printing rate. However, it is finely controlled and does not cause toner deterioration.

  According to a fifth aspect of the present invention, in the fourth aspect of the invention, the developing tank is provided with detecting means for detecting the amount of toner in the developing tank, and the image printing rate is increased. Accordingly, the toner receiving port used for supplying toner to the developing tank is changed from the farthest toner receiving port on the upstream side in the toner circulation direction to the nearest toner receiving port as viewed from the detecting means. Therefore, when the image printing rate is high and a large amount of toner is consumed, the toner flows from the toner receiving port close to the detection means in the developing tank, and the detection means can detect the toner supply in a short time. The toner amount in the developing tank can be prevented from becoming unnecessarily large.

  On the other hand, if the image printing rate is low and the amount of toner consumption is small, for example, if a small amount of toner is allowed to flow in from a toner receiving port far from the detection means in the developing tank, the detection means takes a long time to detect toner replenishment. In other words, the remaining toner in the developing tank and the new toner can be sufficiently mixed.

  According to the sixth aspect of the present invention, since the image forming apparatus includes the toner container according to the first to third aspects and the developing device according to the fourth or fifth aspect, the image forming apparatus is used for developing an electrostatic latent image. Since the toner is not deteriorated, the quality of the formed image is high and stable, and an excellent image forming apparatus is provided.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  First, an outline of an image forming apparatus 3 including a toner container 1 and a developing device 2 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic vertical sectional view showing a schematic structure of an image forming apparatus 3 according to the first embodiment of the present invention. It should be noted that the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention unless otherwise specified, but are merely described. It is just an example.

  As shown in FIG. 1, the image forming apparatus 3 in this embodiment includes a photosensitive drum 4, a charger 5, a drum cleaning member 6, a transfer roller 7, an exposure device 8, a fixing device 9, a data processing means 10, and the like. Each device is provided. Details of the developing device 2, the toner container 1, and the data processing means 10 will be described later.

  First, the photosensitive drum 4 is used as an image carrier. For example, an outer peripheral surface of an aluminum drum has a photoconductive layer made of an amorphous silicon photosensitive member or an OPC photosensitive member, and a driving device (not used). 1) and is rotated in the clockwise direction shown in FIG. 1 at a predetermined process speed.

  The charger 5 as a charging means is provided on the top of the photosensitive drum 4 and uniformly charges the surface of the photosensitive drum 4 to a predetermined potential. The charger 5 is rotationally driven by a driving device (not shown) in the clockwise direction shown in FIG. 1 at a predetermined process speed. The drum cleaning member 6 is provided on the left side of the photosensitive drum 4 when viewed from the front. For example, an elastic body is formed on the blade, and the transfer residual toner on the surface of the photosensitive drum 4 is removed and collected. .

  The transfer roller 7 is provided directly below the photosensitive drum 4 and is formed, for example, by winding a conductive material having a certain elasticity around the outer periphery of an aluminum shaft. The transfer roller 7 forms a nip with the photosensitive drum 4. At the same time that the transfer material P such as paper passes through the nip, a transfer bias current having a polarity opposite to that of the photosensitive drum 4 is applied to the transfer roller 7, and the toner is transferred to the transfer material P. The transfer roller 7 is rotationally driven counterclockwise at a predetermined process speed by a driving device (not shown).

  The exposure device 8 is provided above the photosensitive drum 4 and the developing device 2 and emits laser light modulated in accordance with time-series electric digital pixel signals of image information inputted from a host computer (not shown). By outputting and scanning and exposing the surface of the photosensitive drum 4, an electrostatic latent image based on image information is formed on the surface of the photosensitive drum 4 charged by the charger 5. Data for causing the exposure device 8 to output laser light is created by the data processing means 10.

  The fixing device 9 includes two rollers 9a and 9b. These rollers 9a and 9b are pressed to form a nip. The transfer material P to which the toner has been transferred passes through the nip portion, and at the same time, the fixing device 9 pressurizes and heats, thereby fixing the toner. The fixing device 9 is rotationally driven at a predetermined process speed by a driving device (not shown).

  Here, the image forming operation will be briefly described. First, the photosensitive drum 4 is charged to a predetermined polarity and potential by the charger 5. Next, image data signals such as characters, figures and patterns from a computer (not shown) are processed by the data processing means 10 and transmitted to the exposure apparatus 8. Based on this image data, laser light controlled by the exposure device 8 is irradiated toward the photosensitive drum 4, and an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 4. Next, the toner is ejected from the developing device 2 and the toner image is developed from the electrostatic latent image. Next, the toner image is transferred onto the transfer material P, and then the toner image on the transfer material P is pressurized and heated and fixed by the fixing device 9. The transfer material P discharged from the fixing device 9 is discharged outside the apparatus by a conveying means (not shown). After the toner image is transferred, the toner remaining on the surface of the photosensitive drum 4 is removed by the drum cleaning member 6 by the drum cleaning member 6 to prepare for the next image formation.

  Next, based on FIG. 2, the detailed configuration of the developing device 2 in the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view for explaining the outline of the developing device 2 according to the embodiment of the present invention. In this embodiment, a case where two toner receiving ports 15 are provided will be described.

  As shown in FIG. 2, the developing device 2 in this embodiment includes a developing roller 11, a developing tank 12, a detection unit 13, two stirring spirals 14, two toner receiving ports 15, a frame body 16, and the like. Yes.

  The developing roller 11 is disposed to face the photosensitive drum 4 with a certain gap. The developing roller 11 holds toner on the outer peripheral surface thereof. The toner is supplied to the developing roller 11 from the developing tank 12 (see FIG. 1). By supplying the toner to the developing roller 11, a thin layer of toner is formed on the outer peripheral surface of the developing roller 11.

  Further, the developing roller 11 is provided with a magnet member (not shown) on the roller shaft 11a. The roller shaft 11a is formed by inserting a sleeve 11b made of, for example, aluminum, and is rotationally driven by a driving device (not shown). The The magnet member holds toner. In the case of using nonmagnetic toner, the developing roller 11 for nonmagnetic toner can be used.

  In the developing tank 12, the toner flowing from the toner receiving port 15 is stirred by the stirring spiral 14 and circulated in the developing tank 12. In the case of two-component development, the toner is charged to a predetermined potential by such stirring and circulation (in the case of one-component development, the toner is charged mainly when passing through the toner regulating member 21 instead of stirring. To do). A separation wall 18 is provided in the developing tank 12. The separation wall 18 partitions the inside of the developing tank 12 to form a first transport path 19 and a second transport path 20 for circulating toner. Here, a path closer to the developing roller 11 is referred to as a first transport path 19, and a path farther from the developing roller 11 is referred to as a second transport path 20.

  In the developing tank 12, a first agitation spiral 14 a is provided in the first conveyance path 19, and a second agitation spiral 14 b is provided in the second conveyance path 20. That is, a total of two stirring spirals 14 are provided. The two stirring spirals 14 are rotatably supported by the frame body 16 and are rotationally driven by a driving device (not shown). Each agitation spiral 14 is provided with a fin, and the toner flowing from the toner receiving port 15 is agitated in the direction indicated by an arrow in FIG. 20, and then circulated from the second transport path 20 to the first transport path 19.

  Further, the detecting means 13 for detecting the toner amount is provided in the developing tank 12 at the lower left in FIG. As the detection means 13, a piezoelectric sensor or a light detection sensor can be used. When the detection unit 13 detects that the toner amount in the developing tank 12 is less than a predetermined amount, the toner flows in from the toner receiving port 15 and when the toner in the developing tank 12 reaches the predetermined amount, the toner The inflow of toner from the receiving port 15 is stopped.

  The toner receiving port 15 has a rectangular shape, and two toner receiving ports 15 are provided in this embodiment. The number of toner receiving ports 15 is not limited to two, and may be three or more. Further, the amount of toner flowing into the developing tank 12 can be controlled by changing the number of toner receiving ports 15 to be used according to the amount of toner consumed.

  In the developing device 2 according to the present exemplary embodiment, the first toner receiving port 15a (the left toner receiving port 15 in FIG. 2) is a toner receiving port 15 closer to the upstream side in the toner circulation direction as viewed from the detecting unit 13. ) And the farther second toner receiving port 15b (the right toner receiving port 15 in FIG. 2). Each toner receiving port 15 is also provided on the second transport path 20 on the upper surface of the developing tank 12. The toner flows into the developing tank 12 from the two toner receiving ports 15.

  The frame 16 forms a part of the developing tank 12 and holds the developing roller 11 and each stirring spiral 14. Further, a toner regulating member 21 is provided in the developing device 2 in order to make the thickness of the toner thin layer formed on the outer peripheral surface of the developing roller 11 uniform (see FIG. 1). The toner regulating member 21 is provided substantially vertically above the developing roller 11 (see FIG. 1). The distance between the toner regulating member 21 and the outer peripheral surface of the developing roller 11 is about 0.2 mm to 0.4 mm. Further, as described above, a predetermined voltage is applied to the toner regulating member 21 to promote toner charging in the one-component development.

  Next, based on FIG. 3, the detailed configuration of the toner container 1 used in the first embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view for explaining the toner storage container 1 according to the first embodiment of the present invention.

  The toner container 1 is provided in the developing device 2 (see FIG. 1), and includes a frame 22, a conveying member 23, a toner shutter 24, a conveying screw 25, and the like. As shown in FIG. 3 with reference to the front view in FIG. 1, the frame 22 includes a front wall 22a, a rear wall 22b, a right wall 22c, a left wall 22d, an upper wall 22e (see FIG. 1), and a lower wall 22f (see FIG. 1)). The lower wall 22f is provided with a toner supply port 26 and has two semicircular portions 27 and 28 (see FIG. 1). Of the semicircular portions 27 and 28, the semicircular portion 27 has a radius of the circle smaller than that of the semicircular portion 28.

  The frame body 22 stores toner therein and supports the conveying member 23, the conveying screw 25, and the toner shutter 24 on the front wall 22a and the rear wall 22b, respectively. A toner replenishing port 26 (shown by a dotted line in FIG. 3) is provided in the semicircular portion 27 of the lower surface wall 22f of the frame body 22. The toner replenishing port 26 is provided at a position corresponding to the toner receiving port 15 of the developing tank 12 when the toner storage container 1 is installed in the developing device 2.

  As shown in FIG. 3, the conveying member 23 includes a rotating shaft 23a and a conveying blade 23b fixed to the rotating shaft 23a, and is provided above the semicircular portion 28 (see FIG. 1). The rotating shaft 23a of the conveying member 23 is rotatably supported by the front wall 22a and the rear wall 22b, and protrudes from the rear wall 22b. A gear 29 is fixed to the protruding rotating shaft 23a. A driving force is applied to 29 by driving means (not shown). As a result, the conveying member 23 is rotated (see FIG. 1 and rotated in the direction indicated by the arrow), and conveys the toner in the direction of the toner shutter 24.

  And the conveyance feather | wing 23b has fixed elasticity, for example, consists of a synthetic resin sheet and a film. The transport member 23 rotates while approaching the right wall 22 c and the semicircular portion 28, thereby transporting the toner inside the toner storage container 1 toward the toner shutter 24. Since the conveying blade 23b is provided with a plurality of slits 30 at a predetermined angle, the toner is conveyed so as to be biased toward the front wall 22a of the toner shutter 24.

  As shown in FIG. 3, the toner shutter 24 is provided inside the toner storage container 1 and close to the semicircular portion 27 of the lower wall 22f, and is parallel to the right wall 22c and the left wall 22d. It is provided in the direction (see FIG. 1). The front end (front wall 22 a side) of the shaft portion 24 a protrudes from the front wall 22 a of the toner storage container 1. The front end of the shaft portion 24a is fixedly attached with the gear 31 after being D-cut processed, for example. By applying a drive from the motor M linked to the optical sensor 32 to the gear 31, the toner shutter 24 is rotated in a forward and reverse direction. Note that details of a more specific shape of the toner shutter 24 will be described later.

  The conveying screw 25 is provided so as to pass through the toner shutter 24. The shaft portion 25a protrudes from the front wall 22a and the rear wall 22b, and a gear 33 is fixed to one end of the shaft portion 25a protruding from the rear wall 22b. When a driving force is applied to the gear 33 by a driving means (not shown), the conveying screw 25 is driven to rotate, and the toner in the toner shutter 24 is transferred from the front wall 22a to the rear wall 22b as indicated by arrows in FIG. Transport in the direction. A seal member 25b is provided in the vicinity of both ends of the conveying screw 25 so that toner does not enter the shaft at a portion in contact with the toner shutter 24.

  The toner supply port 26 (shown by a dotted line in FIG. 3) is for supplying toner from the toner container 1 to the developing tank 12 of the developing device 2. In the present embodiment, two are provided in the semicircular portion 27 of the lower wall 22f, the first toner supply port 26a on the front wall 22a side of the toner storage container 1, and the second toner supply port on the rear wall 22b side. 26b is provided.

  The toner supply port 26 is provided at a position corresponding to the toner receiving port 15 provided in the developing device 2 when the toner supplying port 26 is provided in the developing device 2. Accordingly, like the toner receiving port 15, it is formed in a rectangular shape. Specifically, the first toner supply port 26a is provided above the first toner receiving port 15a provided on the second transport path 20 of the developing tank 12 of the developing device 2, and the first toner supply port 15b is provided above the first toner receiving port 15b. The toner supply port 26 is formed so as to correspond to the toner supply port 26b. Then, the toner flows into the developing tank 12 from the toner supply port 26 through the toner receiving port 15.

  Next, based on FIGS. 4 and 5, the detailed configuration of the toner shutter 24 used in the first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a perspective view of the toner shutter 24 according to the first embodiment of the present invention, and FIG. 5 is a schematic diagram showing the position of the replenishment opening 36 of the cylindrical portion 34 of the toner shutter 24 at the time of toner replenishment. FIG.

  As shown in FIG. 4, the toner shutter 24 is formed in a cylindrical shape, and the conveying screw 25 is inserted into the toner shutter 24 as described above. The toner shutter 24 has a shaft portion 24 a at the front end portion (in the direction of the front wall 22 a), and the shaft portion 24 a is supported on the front wall 22 a of the toner storage container 1. FIG. 4 shows a state where the conveying screw 25 is not inserted.

  The toner shutter 24 is provided with a plurality of conveyance openings 35 at both ends of the cylindrical portion 34 along the outer peripheral surface with a certain interval. For example, when the toner enters the toner shutter 24 from the transport opening 35 at the front end portion of the toner shutter 24, the toner is transported toward the transport opening 35 at the rear end portion by the transport screw 25. The toner conveyed to the rear end (partial rear wall 22b side) of the toner shutter 24 is pushed out from the conveyance opening 35. Then, the toner is again conveyed toward the front end of the toner shutter 24 by the conveying member 23. In this way, the toner is stirred and circulated also in the toner container 1.

  In the present embodiment, the first replenishment opening 36a in the direction of the front wall 22a and the second replenishment opening in the direction of the rear wall 22b are in the longitudinal direction of the toner shutter 24 and between the conveyance openings 35. A part 36b is provided. The first supply opening 36a corresponds to the first toner supply port 26a, and the second supply opening 36b corresponds to the second toner supply port 26b in a position, width and length, and is opposed to each other. Provided. That is, if the toner supply port 26 and the supply opening 36 are brought into a state of being opposed to each other by the rotation of the toner shutter 24 in the circumferential direction, the toner flows out from the supply opening 36 through the toner supply port 26. In addition, if the rotation of the toner shutter 24 is controlled so that the replenishment opening 36 is not completely opposed to the toner replenishment port 26 but only a part thereof is opposed, the control of reducing the amount of toner flowing out is also possible. Yes.

  The toner shutter 24 is rotated in the circumferential direction, and this control is performed by a motor M connected to a gear 31a that meshes with a gear 31 fixed to the toner shutter 24 (see FIG. 3). The motor M is freely rotatable forward and backward, and its rotation amount and rotation direction are controlled based on an image printing rate (details will be described later). Further, if a mark such as a notch is provided on the gear 31 and this is detected by the optical sensor 32, the rotational angle in the circumferential direction of the toner shutter 24 is accurately detected. By accurately detecting the toner shutter 24, the amount of rotation and the number of rotations of the motor M can be controlled. As a result, the amount of toner flowing out of the toner shutter 24 can be accurately controlled.

  Here, the rotation angle in the circumferential direction of the toner shutter 24 in the toner container 1 will be described. As shown in FIG. 5A, when the toner does not flow out from the toner storage container 1, the toner shutter 24 is rotated so that the supply opening 36 faces upward. As a result, the toner shutter 24 does not flow out because the portion of the toner shutter 24 having no opening contacts the toner supply port 26.

  As shown in FIG. 5B, when the toner is caused to flow out of the toner storage container 1 by the first supply opening 36a, the toner shutter 24 is set so that the first supply opening 36a faces downward. That is, since the first supply opening 36a of the toner shutter 24 contacts the first toner supply port 26a, the toner flows out from the first supply opening 36a. Accordingly, the toner is supplied to the developing tank 12 through the first supply opening 36a, the first toner supply port 26a, and the first toner receiving port 15a.

  On the other hand, as shown in FIG. 5C, when the toner is caused to flow out of the toner storage container 1 through the second supply opening 36b, the toner shutter 24 is set so that the second supply opening 36b faces downward. That is, since the second supply opening 36b of the toner shutter 24 contacts the second toner supply opening 26b, the toner flows out from the second supply opening 36b. Accordingly, the toner is supplied to the developing tank 12 through the second supply opening 36b, the second toner supply port 26b, and the second toner receiving port 15b.

  In FIG. 6, a developed view of the cylindrical portion 34 of the toner shutter 24 is shown for easy understanding of the replenishment opening 36.

  Thus, by rotating the toner shutter 24, the toner replenishing port 26 through which the toner flows out can be selected. For example, the toner in the developing tank 12 is taken into consideration in view of the distance from the detecting means 13 of the developing tank 12. Fine control such as inflow.

  Here, a specific toner supply operation to the developing tank 12 will be described.

  When the detection unit 13 detects a decrease in the toner amount in the developing tank 12, the toner is supplied to the developing tank 12. In this case, the toner receiving port 15 through which the toner flows into the developing tank 12 is changed depending on the image printing rate. In other words, when the toner shutter 24 is rotated and the replenishment opening 36 to be used is selected, the toner replenishing port 26 through which the toner flows out in the toner storage container 1 is changed, and as a result, the toner receiving port to be used is used. 15 is changed.

  Here, the image printing rate is defined. First, the data that is the basis for calculating the image printing rate is not limited to character data, and any data that is the object of image formation, such as color and black and white images. The image printing rate is a ratio of the number of pixels on which toner is applied to the total number of pixels in one or a plurality of transfer materials P (sometimes referred to as a black and white ratio). Specifically, the image printing rate is a ratio of the number of dots instructing the exposure device 8 to expose the photosensitive drum 4 with respect to the total number of dots of the transfer material P per one or a plurality of transfer materials P. Is calculated by As described above, the image printing rate may be calculated for each sheet or for a plurality of sheets. The calculation of the image printing rate may be performed in the exposure apparatus 8 or by the data processing means 10 for forming data for instructing the exposure apparatus 8 in the image forming apparatus 3 where to expose. You may go.

  The data to be used when calculating the value of the image printing rate may be data of an image formed at the time of toner replenishment, or may be traced back by 10 sheets from the currently formed image. Further, the image data of a unit number such as 100 sheets may be targeted, such as -10, 1-20, 1-30, 1-40, 1-50 sheets. A numerical value obtained by averaging the image printing rates of a plurality of image data can be applied. Note that the image printing rate of the past formed image is generally temporarily stored in the data processing means 10 or the like.

  If the predetermined value of the image printing rate is 6%, for example, if the image printing rate is 6% or more, that is, if the image printing rate is about 6 to 100%, the toner flows from the first toner receiving port 15a. Can be. This is because the average image printing rate when a document consisting only of ordinary characters is printed is often about 6%.

  Further, when the predetermined value of the image printing rate is 3%, the toner flows in from the first toner receiving port 15a even when the image printing rate is 3% or more, that is, when the image printing rate is about 3 to 100%. It may be. This is because, in a color-compatible copying machine, the image printing rate of toner of each color among images to be formed is often about 3% on average. Even in a copying machine for monochrome printing, an image printing rate of 3% may be set to a predetermined value. In short, it can be appropriately set between 1 and 100% according to the purpose of use of the copying machine.

  When the image printing rate is higher than a predetermined value, the amount of toner consumed increases, so that a relatively large amount of toner flows into the developing tank 12. At this time, if the toner shutter 24 is rotated so that the toner flows into the first toner receiving port 15a through the first supply opening and the first toner supply port 26a, the toner shutter 24 can be moved from a location close to the detection means 13. Toner is replenished. As a result, the time required for the detection means 13 to recognize that the toner has been sufficiently supplied is shortened. Therefore, it does not take a long time to detect toner replenishment, and toner replenishment more than necessary is prevented.

  On the other hand, when the image printing rate is lower than the predetermined value, the toner shutter 24 is rotated, and the toner passes through the second supply opening 36b and the second toner supply port 26b, and then from the second toner receiving port 15b to the developing tank 12. Can be allowed to flow into. When image formation with a low image printing rate continues, toner consumption decreases. If this state continues, the toner deteriorates due to stress from the regulating member. The deterioration of the toner causes so-called fogging and causes the quality of the formed image to deteriorate.

  Therefore, if the toner flows in a small amount from the second toner receiving port 15b that is farther from the detection means 13 than the first toner receiving port 15a, the developing tank 12 is replenished with deteriorated or deteriorating toner. The just-made toner mixes moderately. That is, since the toner remaining in the developing tank 12 and the replenishing toner are mixed little by little as compared with the case where a large amount of toner is supplied to the developing tank 12 at a time, the toner in the developing tank 12 is mixed cleanly. Further, since the distance to the detection means 13 is longer than that of the first toner receiving port 15a, the mixing time can be made longer than that of the first toner receiving port 15a.

  Thus, the position of the toner flowing into the developing tank 12 is changed according to the image printing rate, such as the first toner receiving port 15a or the second toner receiving port 15b. This change is performed by rotating the toner shutter 24. The rotation control of the toner shutter 24 is based on a predetermined image printing rate calculated from data stored in the data processing unit 10 or the exposure device 8 or the like. The rotation direction and the rotation amount of the motor M are controlled by the calculated image printing rate.

  Next, 2nd-4th embodiment in this invention is described based on FIGS. The second to fourth embodiments are different in the other way of providing the first embodiment and the supply opening 36. 7 to 9 are development views showing other ways of providing the replenishment opening 36 of the cylindrical portion 34 of the toner shutter 24 in each embodiment.

  The basic configuration of the second to fourth embodiments is the same as that of the first embodiment described with reference to FIGS. 1 to 6. Description and explanation of the drawings are omitted. That is, if the replenishment opening 36 provided is different, the position and number of the corresponding toner replenishing port 26 and toner receiving port 15 differ accordingly, but the same as in the embodiment described with reference to FIGS. You can do it.

  FIG. 7 is a development view when three replenishment openings 36 according to the second embodiment of the present invention are provided. As shown in FIG. 7, in the second embodiment, three supply openings 36 are provided. In this embodiment, for example, the predetermined value of the image printing rate can be set in three stages, and the outflow of toner can be controlled in more detail than in the case where two supply openings 36 are provided. When three supply openings 36 are provided, three toner supply ports 26 and three toner receiving ports 15 are provided. Even when three or more toner receiving ports 15 are provided, as the image printing rate decreases, from the closest toner receiving port 15 to the farther toner receiving port 15 on the upstream side in the toner circulation direction as viewed from the detecting unit 13, If the toner receiving port 15 through which the toner flows into the developing tank 12 is changed, the toner replenishment amount in the developing tank 12 can be controlled in more detail.

  FIG. 8 is a development view in the case where two supply openings 36 according to the third embodiment of the present invention are provided. As shown in FIG. 8, in the third embodiment, two replenishment openings 36 are provided, but one is enlarged and the other is reduced to provide a difference in size. Thus, for example, when the image printing rate is high and the amount of toner consumption is large, the toner can be replenished quickly by using the larger replenishment opening 36. On the other hand, when the image printing rate is low and the toner consumption is small, the toner is replenished little by little by using the smaller replenishment opening 36.

  FIG. 9 is a development view when four supply openings 36 according to the fourth embodiment of the present invention are provided. As shown in FIG. 9, in the fourth embodiment, four supply openings 36 are provided. This is because the supply openings 36 are arranged so that toner flows out from the two supply openings 36 at the same time. Two are added. Thus, for example, when the image forming apparatus 3 is used for the first time or when the toner storage container 1 is replaced, when a large amount of toner is replenished to the developing tank 12, the toner flows out from the two replenishment openings simultaneously. Therefore, the toner is filled at high speed.

  In this manner, in the toner storage container 1 for supplying toner to the developing tank 12, a plurality of toner supply ports 26 for supplying toner to the developing tank 12 are provided on the lower surface. If the toner replenishing port 26 used for replenishing toner to the developing tank 12 is changed according to the image printing rate, the toner replenishing to the developing tank 12 is considered in consideration of the toner consumption due to the level of the image printing rate. Can be finely controlled.

  Further, a toner shutter 24 for controlling the outflow of toner is provided in the toner storage container 1 in the vicinity of the toner supply port 26. The toner shutter 24 has a cylindrical shape and a part of the toner shutter 24 allows the toner to flow out. The toner supply port 26 through which the toner flows out is changed by rotating the toner shutter 24 in the circumferential direction so that the supply opening 36 corresponds to the toner supply port 26. By doing so, the outflow of toner is reliably controlled by the toner shutter 24, which is simpler and more compact than providing a mechanism for selecting the toner supply port 26 to be used outside the toner storage container 1.

  The toner replenishing port 26 used for replenishing toner to the developing tank 12 is viewed from the detecting means 13 for detecting the toner amount in the developing tank 12 provided in the developing tank 12 as the image printing rate increases. By changing from the furthest toner replenishing port 26 upstream of the toner circulation direction in the developing tank 12 to the toner replenishing port 26 closest to the detecting means 13, the image printing rate is high and a lot of toner is consumed. In this case, if the toner flows out from the toner replenishing port 26 close to the detecting means 13 in the developing tank 12, the detecting means 13 can detect the toner replenishment in a short time, and the toner is more than necessary. 12 will not be replenished.

  On the other hand, when the image printing rate is low and the toner consumption is small, the detection means 13 replenishes the toner by causing the toner supply port 26 far from the detection means 13 in the developing tank 12 to flow out, for example, little by little. Although it takes a long time to detect, the remaining toner in the developing tank 12 and the new toner can be sufficiently mixed, and the quality of image formation is improved.

  Further, in the developing device 2 having the developing tank 12 that circulates the toner, the developing tank 12 is provided with a plurality of toner receiving ports 15 for replenishing the toner. If the toner receiving port 15 used for replenishing toner to the developing tank 12 is changed according to the image printing rate, the amount of toner flowing into the developing tank 12 can be finely controlled, leading to toner deterioration. Disappear.

  Further, a detecting means 13 for detecting the amount of toner in the developing tank 12 is provided in the developing tank 12, and when the image printing rate is higher than a predetermined value, the upstream of the toner circulation direction as viewed from the detecting means 13. As toner is supplied to the developing tank 12 from the closest toner receiving port 15 on the side, and the image printing rate increases, the toner receiving port 15 used for supplying toner to the developing tank 12 is viewed from the detection means 13 as a toner circulation. By changing from the farthest toner inlet 15 on the upstream side in the direction to the nearest toner inlet 15, the detection means 13 in the developing tank 12 is used when the image printing rate is high and a large amount of toner is consumed. The toner flows in from the toner receiving port 15 close to, and the detecting means 13 can detect the replenishment of the toner in a short time, and can prevent the toner amount in the developing tank 12 from being increased more than necessary.

  On the other hand, when the image printing rate is low and the toner consumption is small, the detection means 13 detects the replenishment of the toner if, for example, a small amount of toner is allowed to flow into the detection means 13 in the developing tank 12 from the distant toner receiving port 15. Thus, it takes a long time, and the remaining toner containing the deteriorated toner in the developing tank 12 and the new toner can be sufficiently mixed.

  Furthermore, if the image forming apparatus 3 is provided with the toner storage container 1 and the developing device 2, the toner used for developing the electrostatic latent image is not deteriorated. The quality is high and stable, and an excellent image forming apparatus 3 is provided.

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

  For example, as a method of reducing the amount of toner flowing into the developing tank 12 from the second toner receiving port 15b, the toner may be controlled by rotating the toner shutter 24, or the size of the second toner receiving port 15b may be set to the first size. A method of making the size smaller than that of the toner receiving port 15a can be used.

  The present invention can be used in a toner container, a developing device, and an image forming apparatus using the same in an image forming apparatus.

1 is a schematic vertical sectional view showing a schematic structure of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view for explaining an outline of a developing device according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view for explaining the toner storage container according to the embodiment of the present invention. FIG. 3 is a perspective view of a toner shutter according to an embodiment of the present invention. FIG. 6 is a schematic diagram illustrating a position of a replenishment opening of a cylindrical portion of a toner shutter when toner is replenished according to an embodiment of the present invention. FIG. 4 is a development view showing a supply opening of a cylindrical portion of a toner shutter according to an embodiment of the present invention. It is an expanded view at the time of providing three opening parts for supply concerning the 2nd Embodiment of this invention. It is an expanded view at the time of providing two opening parts for supply concerning the 3rd Embodiment of this invention. It is an expanded view at the time of providing four opening parts for supply concerning the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toner storage container 2 Developing apparatus 3 Image forming apparatus 12 Developing tank 13 Detection means 15 Toner receiving port 15a First toner receiving port 15b Second toner receiving port 24 Toner shutter 26 Toner supply port 26a First toner supply port 26b Second toner Replenishment port 36 Replenishment opening 36a First replenishment opening 36b Second replenishment opening

Claims (6)

In a toner storage container for supplying toner to a developing tank for circulating toner provided in the developing device,
A plurality of toner supply ports for supplying toner to the developing tank;
A toner storage container, wherein the toner supply port used for supplying toner to the developing tank among the plurality of toner supply ports is changed according to an image printing rate. A toner shutter for controlling the outflow of toner in the vicinity of the toner supply port is provided in the toner storage container,
The toner shutter is cylindrical and has a plurality of openings for allowing the toner to flow out.
The opening is configured such that when the opening and the toner supply port face each other, toner flows out from the toner supply port.
The toner storage according to claim 1, wherein the toner supply port through which toner flows out is changed by rotating the toner shutter in a circumferential direction so that the opening and the toner supply port are opposed to each other. container.   The toner replenishing port used for replenishing toner to the developing tank is, as viewed from the detecting means for detecting the amount of toner in the developing tank provided in the developing tank as the image printing rate increases, 3. The toner storage container according to claim 1, wherein the toner supply container is changed from the furthest toner supply port on the upstream side in the toner circulation direction to the toner supply port closest to the detection unit. In a developing device having a developing tank for circulating toner,
The developing tank is provided with a plurality of toner receiving ports for supplying toner,
The developing device, wherein among the plurality of toner receiving ports, the toner receiving port used for supplying toner to the developing tank is changed according to an image printing rate. In the developing tank, a detecting means for detecting the amount of toner in the developing tank is provided,
As the image printing rate increases, the toner receiving port used for supplying toner to the developing tank is closer to the toner receiving port closest to the farthest toner receiving port on the upstream side in the toner circulation direction as viewed from the detecting means. 5. The developing device according to claim 4, wherein the developing device is changed to the entrance.   An image forming apparatus comprising: the toner container according to claim 1; and the developing device according to claim 4.

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