JP5593756B2 - Image forming apparatus and toner conveying apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus and a toner conveying apparatus, and more particularly to an image forming apparatus and a toner conveying apparatus suitable for use in a printer, a copying machine, a facsimile, and the like.

  In general, an image forming apparatus includes a developer carrier and a developer (toner) that carry a developer by carrying a developer on the surface up to a development region facing an image carrier (for example, a photoreceptor or an intermediate transfer member). Or toner and carrier), a developer container that supplies toner to the developer carrier, or a developer that supplies toner in the developer container to the developer carried on the developer carrier, and the developer container. And a toner container. In such an image forming apparatus, the greatest purpose of replenishing toner is to replenish and supply the amount of toner conveyed to the image carrier by image output in order to keep the toner density in the developer accommodating portion constant. There is.

  In this replenishment supply of toner, if the amount of toner to be supplied is too large, a high density image is generated due to scattering of toner or an increase in toner density in the developer container. In addition, when toner is excessively replenished, the stirring function of the toner and the carrier performed in the developer accommodating portion may not work and a uniform developer may not be produced. Conversely, if the amount of toner supplied to the image carrier is too small, carrier adhesion may occur during low density image formation or image formation.

  Therefore, the biggest problem of toner replenishment is to reliably replenish the toner amount required by the developer accommodating portion and to keep the toner concentration in the developer accommodating portion constant. As a conventional technique capable of solving such a problem, for example, a technique described in Patent Document 1 is known. This prior art is designed to prevent the toner density from overshooting at the time of initialization of the developing device, and to prevent toner scattering, so that the toner containing portion and the developer containing portion are sealed in the developing device. The member is attached in advance.

  As another conventional technique, for example, a technique described in Patent Document 2 is known. This prior art includes a developer carrying member and a developer containing portion, and includes a developing device that supplies the developer carrying member or the toner carried on the developer carrying member to the toner in the developer containing portion. The process cartridge and the toner container are individually detachable from the main body of the image forming apparatus, and transport the toner from the toner container to the developer container using its own weight. Is provided in the main body of the image forming apparatus.

  Patent Document 2 discloses an image forming apparatus that includes a developing device, a toner container, and a toner conveying device, and the developing device and the toner container are individually detachable from the main body of the image forming apparatus. In the prior art, the toner conveying means uses the weight of the toner, and the toner replenishing portion to the developing means is in the horizontal direction. In the state, in particular, in a state where the fluidity of the toner is good, there is a problem that the toner falls from the end of the toner replenishing port to the developing unit to the developer accommodating portion.

  For this reason, although the above-mentioned conventional technique has a small amount of toner falling for one time, if it is repeated, the toner density in the developer containing portion rises, causing a problem that a high density image or toner scattering occurs, If the toner is excessively replenished, the function of stirring the toner and the carrier carried out in the developer accommodating portion does not work, and a uniform developer may not be produced.

  As a countermeasure against the problems as described above, a path for transporting toner above the lowest point where the toner has fallen by its own weight is formed by the toner transport unit, and a toner dropping port to the developing unit is provided at the end. Such an image forming apparatus is known. However, in this image forming apparatus, when toner is charged into the toner conveyance path from the toner container, if the toner is not filled in the toner conveyance path, the toner flows into the developer accommodating portion. In addition, when an image with a large image area is output, toner replenishment to the developer container increases, so toner replacement in the toner transport path becomes intense and toner fluidity is improved. There is a problem in that toner may flow into the agent container.

  As a countermeasure against the above-described problems, a magnetic field generating unit is provided in the toner transport unit described above, a magnetic carrier is present inside the toner transport path, and the toner transport member constituting the toner transport unit is disposed on the central shaft. There is known an image forming apparatus in which a screw shape is formed around the above. However, this image forming apparatus is used when outputting an image with a large image area and when the screw shape pitch is large or when the length of the above-described toner conveying tube (the region that forms the entire peripheral tube) is small. When an image having a large image area is continuously output, there is a problem that the toner may flow into the developer container.

  As a countermeasure against the above-described problems, an image forming apparatus is known in which the toner conveyance path is 1.5 times or more the screw shape pitch. However, since this image forming apparatus has a long toner conveyance path and a small opening on the upstream side of the toner conveyance path, toner clogging occurs in that portion, and the toner is transferred to the developer container. May not be able to supply. In order to solve this problem, it is possible to suppress the occurrence of toner clogging by providing a toner loosening member at the opening on the upstream side of the toner conveyance path, but the toner is placed on the same rotating body as the piezoelectric sensor scraping member. Since the loosening member is attached, the toner loosening member may adversely affect the piezoelectric sensor. In addition, when the length of the toner loosening member is short, it may be difficult to suppress clogging of the toner when the toner is stirred for a long time and the toner loosening member is curled.

  As countermeasures for this, it is possible to define the order in which the piezoelectric sensor part scraping member and the toner loosening member are attached, or to lengthen the toner loosening member. However, in this case, the provision of the toner loosening member causes a problem that costs such as parts cost and pasting cost increase.

  An object of the present invention is to solve the problems of the prior art as described above, and to effectively loosen the toner from the hopper to the transport path and send it to the developing means so that high-quality development can be performed. Another object is to provide an image forming apparatus and a toner conveying apparatus.

In order to achieve the above-mentioned object, the present invention provides an image carrier, a developing means having a developer container for containing an agent carrier and a developer, and a toner container for supplying toner to the developer container. And a hopper part that is a part of the toner storage means and temporarily stores the toner and supplies the toner to the developing means, and the toner from the hopper part to the developer storage part of the developing means. and a conveying means for transferring said toner conveying means, internally to the toner conveying member of the toner conveying pipe is configured provided, the toner transport pipe, the upper stream portion of the conveying means with an inner diameter greater configured than the inner diameter of the lower flow portion has an opening in the hopper portion, the toner conveying member is configured to have a screw shape of the coil spring around the central axis, wherein Of toner conveying means The outer diameter of the screw shape of the flow section is larger than the outer diameter of the screw shape of the downstream portion, characterized in that the large part is exposed into the hopper through the opening.

  According to the present invention, it is possible to effectively loosen the toner from the hopper portion to the conveyance path and send it to the developing means, so that high-quality development can be performed.

1 is a cross-sectional view showing a basic configuration of a color printer which is an image forming apparatus according to an embodiment of the present invention. It is sectional drawing explaining the detail of a structure of a developing device. 1 is a diagram illustrating a configuration example 1 of a toner conveying device according to an embodiment of the present invention. FIG. FIG. 6 is a diagram illustrating a configuration example 2 of the toner conveying device according to the embodiment of the invention. It is sectional drawing which shows the BB cross section in FIG. FIG. 7 is a diagram for explaining a change with time in a toner supply amount depending on a length of a loosening member. It is a figure explaining the example of the toner scraping operation | movement by the scraping member of a piezoelectric sensor. It is a figure explaining the other example of the toner scraping operation | movement by the scraping member of a piezoelectric sensor. FIG. 10 is a diagram illustrating a configuration example 3 of the toner conveying device according to the embodiment of the invention. FIG. 10 is a diagram illustrating an operation of a configuration example 3 of the toner conveying device. FIG. 10 is a diagram illustrating a detailed configuration example of a conveyance member used in Configuration Example 3 of the toner conveyance device. FIG. 10 is a diagram illustrating another example of a detailed configuration of a conveyance member used in Configuration Example 3 of the toner conveyance device.

  Embodiments of an image forming apparatus, an image forming method, a toner conveying apparatus, and a toner conveying method according to the present invention will be described below in detail with reference to the drawings. In the following description, components having the same functions, shapes, and the like, and constituent elements such as components are denoted by the same reference numerals and will not be described later. In addition, in order to simplify the drawings and the description, even components that are to be represented in the drawings may be omitted as appropriate without being specifically described in the drawings.

  FIG. 1 is a sectional view showing a basic configuration of a color printer which is an image forming apparatus according to an embodiment of the present invention. An image forming apparatus according to an embodiment of the present invention described below is an example of a color printer (hereinafter abbreviated as a printer) that can form a full-color image using a tandem method.

  The printer shown in FIG. 1 basically has the same configuration as the electrophotographic printer disclosed in Patent Document 2, for example. In this printer, a sheet feeding unit 2 for storing a sheet P as a recording material is disposed at a lower portion of the apparatus main body 1, and an image forming unit 3 is disposed above the sheet feeding unit 2. The image forming unit 3 includes, as a plurality of image forming units including an image carrier, an image forming unit 8 including four image forming units 8Y, 8C, 8M, and 8BK, and a plurality of rollers 4, 5, 6 and An intermediate transfer unit 7 having an intermediate transfer belt 7a as an intermediate transfer member constituted by an endless belt having flexibility wound around these rollers 4, 5 and 6, and each of the image carriers described above by light. The optical writing unit 15 is an optical writing unit that performs writing, and a fixing device 19 that fixes a toner image on the paper P.

  The image forming units 8Y, 8C, 8M, 8BK and the intermediate transfer unit 7 are configured to be detachable from the apparatus main body 1. A conveyance path R for conveying the paper P onto which the image formed by the image forming unit 3 is transferred is formed between the paper feeding unit 2 and the fixing device 19. The roller 6 constitutes a secondary transfer device which will be described later, and is disposed facing the conveyance path R of the paper P indicated by a one-dot chain line. An end portion R1 of the transport path R is opened to face a paper discharge tray 22 as a stacking portion constituting the paper discharge portion 20 formed on the upper portion of the apparatus main body 1. The image forming units 8Y, 8C, 8M, and 8BK are also referred to as process cartridge units (PCU) 8Y, 8C, 8M, and 8BK.

  The space between the roller 4 and the roller 5 of the intermediate transfer belt 7a corresponds to the lower side belt running side of the belt 7a. In the intermediate transfer belt 7 a, a secondary transfer roller 16 serving as a secondary transfer device is disposed at a portion facing the roller 6 so as to face the conveyance path R, and a belt for cleaning the belt surface at a portion facing the roller 4. A cleaning device 17 is provided.

  The image forming unit 8 is disposed below the intermediate transfer belt 7a so as to face the lower belt running side of the intermediate transfer belt 7a. In the embodiment of the present invention, the image forming units 8Y, 8C, 8M, and 8BK have basically the same configuration. In FIG. 1, only the configuration of the image forming unit 8BK is represented by the reference numerals of the constituent elements. It is attached. Each of the image forming units 8Y, 8C, 8M, and 8BK includes a photosensitive drum 10 as an image carrier in contact with the intermediate transfer belt 7a. Around each photosensitive drum 10, a charging device 11, a developing device 12 as a developing means, and a cleaning device 13 are arranged. Transfer rollers 14 as transfer means for performing primary transfer are provided inside the intermediate transfer belt 7a at positions where the respective photosensitive drums 10 are in contact with the intermediate transfer belt 7a.

  Each of the image forming units 8Y, 8C, 8M, and 8BK is different only in the color of the toner as the developer stored in each developing device 12, and the other configurations are basically the same. The developing devices 12 of the image forming units 8Y, 8C, 8M, and 8BK contain yellow, cyan, magenta, and black toners, respectively. Each developing device 12 is configured to supply replenishment toner from toner bottles 32Y, 32C, 32M, and 32BK that are mounted and set above the developing device when the amount of toner decreases.

  FIG. 2 is a cross-sectional view illustrating details of the configuration of the developing device 12. In FIG. 2, the reference numeral “Y” representing yellow is added to the end of the reference numeral of the developing device 12, and the detailed configuration of the developing device 12Y of the image forming unit 8Y will be described as a representative. Similarly, the developing device 12C shown in parentheses in FIG. 2 is disposed in correspondence with the image forming unit 8C, the developing device 12M in correspondence with the image forming unit 8M, and the developing device 12BK in correspondence with the image forming unit 8BK, respectively. Represents things.

  The developing device 12Y includes a magnetic field generating means inside, and carries a two-component developer (hereinafter simply referred to as “developer”) including carrier and toner as magnetic particles on the surface, and the outer periphery of the photosensitive drum 10. A developing sleeve 25 as a developer carrying member that is a developer carrying means that conveys to a developing region facing the surface, and a developer regulating member that regulates the layer thickness of the developer carried and carried on the developing sleeve 25 A doctor 26, a developer container 27 that is formed on the upstream side of the doctor 26 in the developer conveyance direction and that is not conveyed to the aforementioned development area and that is regulated by the doctor 26, and is adjacent to the developer container 27 The toner storage unit 28 is configured to store the toner and the toner transporting screw 29 for stirring and transporting the toner.

  The optical writing unit 15 irradiates the surface of each photosensitive drum 10 with the light-modulated laser light L, and forms a latent image for each color on the surface of the photosensitive drum. In the embodiment of the present invention, It is arranged below the image forming unit 8.

  Next, the operation of the above-described printer will be described.

  In the printer shown in FIG. 1 configured as described above, when the image forming operation is started, the photosensitive drums 10 of the image forming units 8Y, 8C, 8M, and 8BK are rotated in the clockwise direction by a driving device (not shown). The surface of each photosensitive drum 10 is uniformly charged to a predetermined polarity by the charging device 11. Laser light L from the optical writing unit 15 is irradiated on the outer peripheral surface of each charged photoconductive drum 10 to form an electrostatic latent image on each surface. At this time, the image information to be exposed to each photosensitive drum 10 is single-color image information obtained by separating a desired full-color image into color information of yellow, cyan, magenta, and black. The electrostatic latent image formed in this way is visualized as a toner image by the toner of each developing device 12 when passing through a position facing the developing device 12 as each photosensitive drum 10 rotates.

  Here, the operation of the developing device 12Y will be described in detail with reference to FIG. In the developing device 12Y, a developer layer is formed on the developing sleeve 25. Further, the toner is taken into the developer from the developer accommodating portion 27 by the movement of the developer layer conveyed by the rotation of the developing sleeve 25. The toner is taken in so that the developer is within a predetermined toner density range. The toner taken into the developer is charged by frictional charging with the carrier. The developer containing charged toner is supplied to the surface of the developing sleeve 25 having a magnetic pole inside and is carried by the magnetic force. The developer layer carried by the developing sleeve 25 is regulated by the doctor 26 during the conveyance of the developing sleeve 25 in the counterclockwise direction indicated by the arrow in FIG. Thereafter, the toner is conveyed to a developing area facing the photosensitive drum 10. Then, development based on the electrostatic latent image formed on the photosensitive drum 10 is performed in the development region. The developer layer remaining on the developing sleeve 25 is conveyed to the upstream portion of the developer accommodating portion 27 in the developer conveying direction as the developing sleeve 25 rotates.

  Referring back to FIG. 1, one of the plurality of rollers 4, 5, 6 around which the intermediate transfer belt 7a is wound is rotationally driven in a counterclockwise direction by a driving device (not shown). When the transfer belt 7a is driven to run in the counterclockwise direction indicated by an arrow in FIG. 2, the other rollers are driven to rotate. The yellow toner image formed by the image forming unit 8Y including the developing device 12Y having yellow toner as described with reference to FIG. 2 is transferred to the intermediate transfer belt 7a traveling in this way by the transfer roller 14. The Thereafter, a cyan toner image, a magenta toner image, and a black toner image formed by the image forming units 8C, 8M, and 8BK are sequentially transferred onto the transferred yellow toner image by the transfer roller 14, and thus the intermediate transfer belt 7a. Carries a full-color toner image on its surface.

  Residual toner adhering to the surface of each photosensitive drum 10 after the toner image is transferred is removed from the surface of the photosensitive drum 10 by each cleaning device 13, and then the surface is neutralized by a neutralizing device (not shown). The surface potential is initialized to prepare for the next image formation.

  On the other hand, the sheet P fed from the sheet feeding unit 2 is sent to the conveyance path R, and a pair of registration rollers disposed on the upstream side (the sheet feeding unit 2 side) of the conveyance path R with respect to the secondary transfer roller 16. The sheet feeding timing is taken by 18, and the roller 6 and the secondary transfer roller 16 are fed to the facing transfer portion. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the surface of the intermediate transfer belt 7 a is applied to the secondary transfer roller 16, whereby the toner image on the surface of the intermediate transfer belt 7 a is applied onto the paper P. Transcribed at once. The sheet P on which the toner image has been transferred is conveyed to the fixing device 19, and when passing through the fixing device 19, heat and pressure are applied to melt and fix the toner image. The sheet P on which the toner image is fixed is conveyed to the discharge unit 21 disposed at the end R1 of the conveyance path R and is discharged to the discharge tray 22. After the toner image is transferred to the paper P, the toner remaining on the belt 7 a is removed from the belt cleaning device 17 by the intermediate transfer belt 7 a.

  In the tandem printer configured as described above, four image forming units 8Y, 8M, 8C, and 8BK are provided facing the intermediate transfer belt 7a, and the toner images of the respective colors are sequentially transferred onto the intermediate transfer belt 7a. Therefore, for example, the image forming time is significantly longer than that of a type in which a single image forming means has a four-color developing device, and a toner image is transferred onto an intermediate transfer belt and then transferred onto a sheet. It can be shortened. In the printer described above, the paper discharge tray 22 as a stacking unit is disposed on the upper portion of the apparatus main body 1, so that it is not necessary to project the paper discharge tray 22 from the apparatus main body 1. This has the advantage that the occupied area can be reduced.

  The image forming operation in the case where a full color image is formed on the paper P has been described above. However, a single color image is formed using any one of the image forming units of the image forming unit 8, or two colors or three colors are formed. A color image can also be formed. Further, when monochrome printing is performed using the printer according to the embodiment of the present invention, an electrostatic latent image is formed only on the photosensitive drum 10 of the image forming unit 8BK, and is developed by the image forming unit 8BK to be developed on the paper P And then fixed by the fixing device 19.

  FIG. 3 is a diagram illustrating a configuration example 1 of the toner conveyance device according to the embodiment of the present invention. Next, a configuration example 1 of the toner conveyance device according to the embodiment of the present invention will be described with reference to FIG.

  In the toner conveying device according to the embodiment of the present invention, taking the toner conveying device 50BK for black toner as an example, as shown in FIG. 3, a hopper unit that drops the toner in the toner bottle 32BK to the lower part of the toner conveying path. 64, a toner transport path that includes a toner transport member 60 that is provided inside the toner transport pipe 63 and the toner transport pipe 63 and has a transport screw mechanism that moves the toner to the downstream side in the transport direction by its rotational movement; A driving motor 55 as a driving means for driving the conveying member 60 and the toner bottle 32BK is provided. In the above description, the toner bottle 32BK and the hopper portion 64 constitute a toner storage unit in the present invention.

  The toner transport tube 63 is formed of a resin mold, and the gap (maximum and minimum dimensions) between the inner peripheral wall of the toner transport tube 63 and the outer periphery of the toner transport member 60 is set to about 0.1 mm to 0.2 mm. Has been.

  As described above, the toner conveying member 60 is installed in the toner conveying tube 63 so as to be substantially inscribed, and the toner is accumulated in the toner conveying tube 63 by applying a force to the toner to move in the conveying direction. Can be prevented. As a result, it is possible to prevent problems caused by the toner accumulated in the toner transport pipe 63 flowing into the developing device 12BK of the image forming unit 8BK at once due to some impact or the like.

  Further, as shown in FIG. 3, the toner transport pipe 63 is disposed so as to have an inclined layout so that the toner is transported upward as it goes downstream. Then, the toner in the toner bottle 32BK passes through the hopper portion 64 to the lowest point 65 of the toner transport pipe 63, and then moves along the screw in the transport pipe 63 by the rotation of the screw of the transport member 60. Then, it is supplied to the developing means from the dropping port 66.

  In the foregoing, toner material in the toner bottle 32BK is made of polyester resin, and toner particles having a particle diameter range of 6.0 μm to 12.5 μm are filled into the toner bottle 32BK. Was set with the toner fluidity improved by shaking up and down several times.

  At this time, in the toner conveying device shown in FIG. 3 as the configuration example 1, the toner in the toner bottle 32BK flows into the lower portion of the toner conveying tube 63 through the hopper 64 and the opening 78 of the toner conveying tube 63. About 10 g of toner flowed into the toner storage portion 28 of the developing device 12 from the dropping port 66. The toner concentration control range of the developer accommodating portion is 4 wt% to 9 wt%. However, when about 10 g of toner flows, the toner concentration increases to 11 wt%, and this amount is not negligible in controlling the toner concentration. Met.

  Therefore, in the toner conveying apparatus of the configuration example 1 shown in FIG. 3, the magnetic field generating means 71 is provided in the entire outer periphery of the conveying pipe 63 and the magnetic carrier 72 is filled in the toner conveying path, whereby the toner from the toner dropping port 66 is filled. The fall amount could be reduced to 0 to 0.5 g. In this case, the toner concentration in the developer accommodating portion hits 7.2 wt% at worst, and it was confirmed by experiment that there is no influence on the toner concentration control at this level.

  Further, in the example shown in FIG. 3, the length (area of the entire circumference tube) a of the toner conveying tube is set to 1.5 times or more (a> 1.5p) of the screw-shaped pitch p. Yes. As a result, even when images having a large image area were continuously formed (100 sheets of all A3 solid sheets), the flow of toner into the developer accommodating portion could be suppressed. This was confirmed by experiments.

  FIG. 4 is a diagram showing a configuration example 2 of the toner conveying device according to the embodiment of the present invention, FIG. 5 is a sectional view showing a section BB in FIG. 4, and FIG. 6 is a change with time of the toner supply amount depending on the length of the loosening member. FIG. 7 is a diagram for explaining an example of the toner scraping operation by the scraping member of the piezoelectric sensor, and FIG. 8 is a diagram for explaining another example of the toner scraping operation by the scraping member of the piezoelectric sensor.

  Hereinafter, a configuration example 2 of the toner conveyance device will be described with reference to FIGS. 4 to 8. The configuration example 2 of the toner conveyance device described here is the same as the configuration example 1 of the toner conveyance device shown in FIG. This is an example in which a loosening member 75 is provided in the hopper portion 64 above the opening 78 of the transport pipe 63, and the other configuration is the same as in the configuration example 1 shown in FIG. The same applies to the configuration examples of other toner conveying apparatuses described later, but the magnetic field generating means 71 may not be provided.

  In the configuration example 2 shown in FIG. 5, a loosening member 75 having a thickness of 0.05 mm to 0.2 mm and using PET as a material is provided above the opening 78 of the toner conveying tube 63, and the piezoelectric sensor 77 is scraped. A member 76 is provided in the hopper portion 64. The aforementioned loosening member 75 has a different structure from the scraping member 76 of the piezoelectric sensor 77, and these are attached to a rotating body 67 different from the toner conveying member 60.

  As the rotating body 67 rotates, the scraping member 76 and the loosening member 75 rotate in the direction of the arrow shown in FIG. 5, thereby scraping off the toner on the piezoelectric sensor 77 and loosening the toner in the opening 78. The toner can be transported to the developer accommodating portion without clogging the toner.

  If the thickness of the loosening member 75 is too thin, the clogging of the toner clogged in the opening 78 cannot be sufficiently eliminated, and if the thickness of the loosening member 75 is too thick, the loosening member 75 is rotated by the rotation of the rotating body 67. By making strong contact with the inner walls 79 (a) and 79 (b) of the hopper portion 64 which is a part of the storage means, a toner agglomerate is generated, and the toner agglomerate is transferred to the developer storage part of the developing device 12. As a result of being transported and clogging the doctor 26, white streaks on the image will be generated. Therefore, in the embodiment of the present invention, the thickness of the loosening member 75 is set to 0.05 mm to 0.2 mm, which can sufficiently eliminate the clogging of the toner and also suppress the generation of slow agglomerates. it can. This was confirmed by experiments.

  As shown in FIG. 5, the toner conveyance device of the configuration example 2 according to the embodiment of the present invention described above has a loosening member 75 first attached to a rotating body 67 different from the toner conveyance member 60. The scraper member 76 of the piezoelectric sensor 77 is provided. Thus, when the toner on the piezoelectric sensor 77 is scraped off, the scraping member 76 of the piezoelectric sensor 77 evenly contacts the contact portion of the piezoelectric sensor 77 prior to the loosening member 75 as shown in FIG. Can be scraped horizontally and horizontally. However, in the reverse configuration, as shown in FIG. 8, when the loosening member 75 passes first, the loosening member 75 is longer than the scraping member 76 of the piezoelectric sensor 77. When the piezoelectric sensor 77 is scraped off, the contact portion is slanted and cannot be scraped evenly, and there is a possibility of erroneous detection.

  Further, since the loosening member 75 is long enough to reach the inside of the toner conveying tube 63, it gradually curls when the toner is stirred for a long time. If the loosening member 75 is shortened to suppress this curling, toner clogging cannot be suppressed, and the toner replenishment amount gradually decreases. However, if the loosening member 75 has a sufficiently long length, it is possible to suppress clogging of toner even if it is curled by long-time operation.

  FIG. 6 shows the change over time in the toner supply amount depending on the length of the loosening member 75, and as can be seen from this figure, the length of the loosening member 75 is long enough to reach the inside of the toner transport pipe 63. Then, even if the apparatus is operated for a long time, the toner replenishment amount does not deviate from the range of the replenishment amount standard value of 0.24 g / s to 0.36 g / s. However, when the length of the loosening member 75 does not reach the inside of the toner conveyance tube 63, the toner replenishment amount deviates from the range of the replenishment amount standard value of 0.24 g / s to 0.36 g / s. End up.

  FIG. 9 is a diagram illustrating a configuration example 3 of the toner conveyance device according to the embodiment of the present invention. FIG. 10 is a diagram illustrating an operation of the configuration example 3 of the toner conveyance device. Next, a configuration example 3 of the toner conveyance device will be described. explain.

  In the above-described configuration example 2 of the toner conveying device according to the embodiment of the present invention, as shown in FIG. 5, the loosening member 75 is provided. Therefore, the parts cost of the loosening member 75 and the application fee are required. This increases costs. In order to avoid this, in the configuration example 3 of the toner conveyance device shown in FIG. The inner diameter is made larger than the downstream part. As a result, the toner in the opening 78 that is likely to be clogged with toner can be loosened due to its conveying effect. In the example shown in FIG. 9, the conveying member 60 is formed by a coil spring. When the conveying member 60 is rotated by the coil spring, the toner conveying member 60 abuts against the lower surface of the inner wall of the toner conveying tube 63 and bounces as shown in FIG. As a result, the toner conveying member 60 is exposed from the opening 78 above the toner conveying tube 63, and the upper toner can be crushed from below.

  FIG. 11 is a diagram illustrating a detailed configuration example of the conveyance member 60 used in the configuration example 3 of the toner conveyance device.

  As described above, the conveyance member 60 used in the configuration example 3 of the toner conveyance device is formed by the coil spring. The upstream part is formed in a conical shape, and the downstream part is formed in a straight line in accordance with the inner diameter of the toner conveying tube 63. At both ends of the conveying member 60 having such a shape, shaft diameter portions having shaft diameters that can be fitted to the slide bearings at both ends of the toner conveying tube 63 are provided, and one end of a spring is provided at the shaft diameter portion. Is inserted and fixed to the shaft diameter portion by brazing solder together with the central axis of the conveying member 60. The shaft diameter portions at both ends of the conveying member 60 are provided with grooves on the outside thereof, and are fixed to the sliding bearings at both ends of the toner conveying tube 63 by an E ring (retaining ring) (not shown).

  FIG. 12 is a diagram illustrating another example of the detailed configuration of the conveyance member 60 used in the configuration example 3 of the toner conveyance device.

  The configuration example of the conveying member 60 shown in FIG. 12 is obtained by decentering the conical portion upstream of the conveying member 60 formed by the coil spring in the example shown and described in FIG. By adopting such a configuration, the eccentric part of the coil spring periodically contacts the lower surface of the toner conveying tube 63 with a strong and weak strength, and the way of exposure from the opening 78 is regularly. Will change. Thereby, the toner loosening effect can be further improved.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed part 3 Image forming part 4, 5, 6 Roller 7 Intermediate transfer unit 7a Intermediate transfer belt 8 Image forming part 8Y, 8C, 8M, 8BK Image forming unit 10 Photosensitive drum 11 Charging device 12 Developing device 13 Cleaning device 14 Transfer roller 15 Optical writing unit 16 Secondary transfer roller 17 Belt cleaning device 18 Registration roller pair 19 Fixing device 20 Paper discharge unit 21 Paper discharge unit 22 Paper discharge tray 25 Developing sleeve 26 Doctor 27 Developer storage unit 28 Toner storage unit DESCRIPTION OF SYMBOLS 29 Toner conveyance screw 50BK Toner conveyance apparatus 32BK Toner bottle 60 Toner conveyance member 63 Toner conveyance pipe 64 Hopper part 66 Drop port 67 Rotating body 71 Magnetic field generating means 72 Magnetic carrier 75 Unraveling member 76 Scraping member 77 Piezoelectric sensor 78 Opening part

JP 2002-268353 A JP 2004-139031 A

Claims (10)

An image carrier;
A developing means comprising a developer carrying means and a developer containing portion for containing the developer;
Toner storage means for supplying toner to the developer storage section;
A hopper unit that is a part of the toner storage unit, temporarily stores the toner, and supplies the toner to the developing unit;
Toner conveying means for conveying toner from the hopper to the developer accommodating portion of the developing means;
Have
The toner conveying means is configured by providing a toner conveying member inside a toner conveying tube,
The toner transport pipe, the inner diameter of the upper stream portion with larger formed than the inner diameter of the lower flow portion of the conveying means has an opening in the hopper portion,
The toner conveying member is configured to have a screw shape by a coil spring around a central axis, and the outer diameter of the screw shape at the upstream portion of the toner conveying means is larger than the outer diameter of the screw shape at the downstream portion, An image forming apparatus, wherein a large portion is exposed in the hopper through the opening.   2. The image forming apparatus according to claim 1, wherein a portion having a large outer diameter of the screw shape of the toner conveying member is configured to repeatedly collide with a lower surface of the toner conveying tube when the toner conveying member is driven. An image forming apparatus.   3. The image forming apparatus according to claim 1, wherein a central portion of the winding is eccentric with respect to a downstream portion of a portion of the toner conveying member having a large screw-shaped outer diameter. apparatus.   4. The image forming apparatus according to claim 1, wherein the toner conveying means has a magnetic field generating means in the middle of the toner conveying tube serving as a toner conveying path, and a magnetic carrier is accommodated in the toner conveying tube. An image forming apparatus.   5. The image forming apparatus according to claim 1, wherein the toner conveying unit has a length of a region in which the toner conveying tube is a full-circumferential tube being 1.5 times the pitch of the screw shape. An image forming apparatus characterized by the above. An image carrier;
A developing means comprising a developer carrying means and a developer containing portion for containing the developer;
Toner storage means for supplying toner to the developer storage section;
A hopper unit that is a part of the toner storage unit, temporarily stores the toner, and supplies the toner to the developing unit;
Toner conveying means for conveying toner from the hopper to the developer accommodating portion of the developing means;
In a toner conveying device in an image forming apparatus configured to include:
The toner conveying means as the toner conveying device is configured by providing a toner conveying member inside a toner conveying tube,
The toner transport pipe, the inner diameter of the upper stream portion with larger formed than the inner diameter of the lower flow portion of the conveying means has an opening in the hopper portion,
The toner conveying member is configured to have a screw shape by a coil spring around a central axis, and the outer diameter of the screw shape at the upstream portion of the toner conveying means is larger than the outer diameter of the screw shape at the downstream portion, A toner conveying device, wherein a large portion is exposed in the hopper through the opening.   7. The toner conveying device according to claim 6, wherein a portion having a large screw-shaped outer diameter of the toner conveying member is configured to repeatedly collide with a lower surface of the toner conveying tube when the toner conveying member is driven. And a toner conveying device.   8. The toner conveying device according to claim 6, wherein a screw-shaped outer diameter portion of the toner conveying member having a large outer diameter is eccentric with respect to a downstream portion. apparatus.   9. The toner conveying device according to claim 6, 7 or 8, wherein a magnetic field generating means is provided in the middle of the toner conveying tube serving as a toner conveying path, and a magnetic carrier is accommodated in the toner conveying tube. Toner transport device.   10. The toner conveying device according to claim 6, wherein the length of the region where the toner conveying tube is a full circumference tube is 1.5 times or more the pitch of the screw shape. 10. A toner conveying device.

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