JP3912072B2 - Toner transport device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner transport device for transporting toner (colored fine particles), and in particular, transports toner used in an image forming apparatus such as a printer, a copying machine, a facsimile machine, and a multi-function machine well without agglomeration. The present invention relates to a toner conveying device that can perform the above-described operation.
[0002]
[Prior art]
In an image forming apparatus such as a printer using an electrophotographic method, generally, toner that adheres excessively to an image bearing member such as a photosensitive member that bears a toner image formed by the electrophotographic process or the like or an intermediate transfer member. Although a cleaning device is provided for removal, there is also a mechanism for transporting and collecting the toner removed by the cleaning device to a toner collection unit such as a collection box.
[0003]
The toner is normally transported from the cleaning device to the toner recovery unit as illustrated in FIG. 11, and the toner transport member rotates in the space of the toner transport path 220 formed in the housing 210 of the cleaning device 200. 230, that is, using a toner conveying device that conveys by a member (a so-called screw auger) in which a spiral blade 232 wound around a rotating shaft 231 rotating in the space is formed at a predetermined spiral pitch. That is, in such a toner conveying device, the toner conveying member 230 is rotationally driven in a predetermined direction (the direction of the arrow m), so that the spiral blade 232 moves as if moving forward in the toner conveying direction. Therefore, the toner in the transport space 117 is fed by the movement of the blades. In the figure, reference numeral 250 denotes a cleaning blade, 260 denotes a seal member, and 270 denotes an image carrier or intermediate transfer member.
[0004]
By the way, in such a toner conveying device, the toner itself may aggregate and harden due to the conveying action of the toner conveying member 230, and as a result, the toner may not be smoothly conveyed.
[0005]
In order to solve such a problem, the present applicant, for example, from a Mylar sheet or the like that is fixedly arranged so that a part of the free end 240a can come into contact with the toner conveying member 230 as shown in FIGS. A measure for attaching the sheet-like elastic member 240 is adopted. The sheet-like elastic member 240 has a protruding tip portion (convex portion) 245 that can be interposed between the spiral blades 232 of the toner conveying member 230 at a pitch β (= α) corresponding to the spiral pitch α of the blades 232. A toner conveying member 230 having a plurality of free ends 240a, the free ends 240a facing each other in parallel with the rotation shaft 231 of the toner conveying member, and the protruding tip 245 of the free end 240a rotating. It is fixedly installed in such a state that it can periodically come into contact with the spiral blade 232.
[0006]
Then, as shown in FIG. 13, when the toner conveying member 230 rotates, the sheet-like elastic member 240 advances or moves the convex portion 245 of the free end 240a toward the toner conveying direction (arrow f direction). Thus, the blades 132 are periodically (and simultaneously) contacted with the moving blades 132 and pushed downward by the blades 132, so that the entire free end 240a is displaced so as to be lowered, and the protruding tip portion 245 thereof. Is moved over the blades 132, the entire free end 240a is displaced so as to rise back to the original position. Therefore, the sheet-like elastic member 240 swings in the vertical direction with its free end 240 a orthogonal to the rotation shaft 231 of the toner conveying member 230. As a result, the toner transported by the toner transport member 230 is shaken, so that the lump of toner that is likely to aggregate is broken. Reference numeral 221 in the drawing indicates a wall surface of the toner transport path 220.
[0007]
[Problems to be solved by the invention]
However, the toner conveying apparatus to which such a sheet-like elastic member 240 is attached has the following problems.
[0008]
That is, when the entire free end 240a of the sheet-like elastic member 240 performs a swinging motion so as to periodically get over by the periodic contact of the protruding tip 245 with the spiral blade 232 as described above, the toner conveying member that rotates. Since 230 receives a reaction force from the sheet-like elastic member 240 due to the swinging motion (strictly, the process in which the protruding tip 245 rides on the spiral blade 232), it is deformed to be bent slightly as illustrated in FIG. There is a problem that an eccentric state occurs, and the outer peripheral portion of the spiral blade 232a in the eccentric portion collides with a portion (for example, the wall surface 221) of the toner conveyance path 220, and noise such as a striking sound is generated. This noise tends to be amplified as the rotational speed of the toner conveying member 230 increases.
[0009]
Incidentally, in order to solve this problem, the present inventors tried to take a measure to reduce the thickness of the sheet-like elastic member 240. However, in such a measure, only the protruding tip portion 245 portion contacts the spiral blade 232. Thus, the swinging motion of the entire free end 240a is reduced to the extent that it swings and deforms, thereby reducing the toner breaking effect of the sheet-like elastic member 240. Therefore, such a countermeasure cannot be an effective solution.
[0010]
The present invention has been made in view of such circumstances, and noise caused by periodic contact between the sheet-like elastic member and the toner conveying member without reducing the toner breaking effect of the sheet-like elastic member. It is a main object of the present invention to provide a toner conveying device capable of preventing the occurrence of the above.
[0011]
[Means for Solving the Problems]
The toner conveying device of the present invention capable of solving the above-mentioned problems is formed with a conveying path portion for conveying toner, and a spiral blade wound around the rotating shaft rotating in the space of the conveying path portion at a predetermined helical pitch. The toner conveying member and the projecting tip of a shape that can be interposed between the spiral blades of the toner conveying member have a plurality of free ends formed at a pitch corresponding to the helical pitch of the spiral blades. The sheet-like elasticity is fixedly installed in such a manner that it faces the rotation axis of the toner conveying member in a substantially parallel state and the protruding tip of its free end can periodically come into contact with the rotating spiral blade of the toner conveying member A part of the pitch of the protruding tip at the free end of the sheet-like elastic member is different from the helical pitch of the spiral blades of the toner conveying member. It is an feature.
[0012]
Here, the toner conveyance path portion may have any shape having a space capable of conveying the toner by rotation of the toner conveyance member, and the overall form thereof is not particularly limited. . The spiral pitch of the spiral blades in the toner conveying member is usually constant, but a part thereof may be different if necessary.
[0013]
In the sheet-like elastic member, the pitch of the protruding tip at the free end is basically the same (same) pitch as the spiral pitch of the spiral blade. Only a part of is different from the spiral pitch by a predetermined ratio. The sheet-like elastic member is not limited to the projecting tip when the projecting tip is in contact with the spiral blade of the toner conveying member. What is necessary is just to have. The sheet-like elastic member is fixed to a predetermined portion (may be a part of the conveyance path portion) by a predetermined fixing means on the end (base end) side located on the side facing the free end. To be installed.
[0014]
According to such a toner conveying device, the protruding tip end portions that are separated on both sides of a portion where the pitch of the plurality of protruding tip end portions formed at the free end of the sheet-like elastic member is different from the spiral pitch are defined as boundaries. Group) come into contact with each other at a timing (period) relatively different from the spiral blades of the toner conveying member. As a result, the load due to the reaction force applied to the toner conveying member when the protruding tip portion at the free end of the sheet-like elastic member comes into contact with the rotating spiral blade of the toner conveying member is affected by the plurality of protruding tip portions at the free end. Compared to the case where all of them are in contact with the spiral blades of the toner conveying member at the same time (prior art), they are dispersed and reduced. As a result, the toner conveying member is deformed so as to be bent and is not easily decentered, and the spiral blade of the toner conveying member is prevented from colliding with a portion of the toner conveying path. Further, in this toner conveying device, since it is not necessary to reduce the thickness of the sheet-like elastic member as in the prior art, there is no possibility of reducing the toner breaking effect by the sheet-like elastic member.
[0015]
Further, in such a toner conveying device, a portion having a pitch different from the helical pitch of the protruding tip portion of the sheet-like elastic member can be present at an arbitrary portion in the width direction of the free end. Preferably, the free end may be configured to be present at least at portions that are both ends of the central region in the width direction. The central region can be, for example, a region corresponding to a ratio of 1/3 to 1/2 in the full width direction of the free end, and further to a ratio of 1/3 to 2/3.
[0016]
In such a configuration, the load caused by the reaction force from the central region in the width direction of the free end, which is the largest of the loads caused by the reaction force of the sheet-like elastic member applied to the rotating toner conveying member, is accurately determined. Can be reduced. For example, it is effective when using a toner conveying member whose both ends are pivotally supported.
[0017]
Further, in each of the toner conveying devices as described above, it is preferable to form a cut portion in a concave portion between the protruding tip portions formed at a pitch different from the helical pitch. In general, the cut portion is preferably a deeper cutout (recess portion) between the protruding tip portions, but it may be simply a cut line if necessary.
[0018]
In such a configuration, the protruding tip portions (groups) that exist separately on both sides of the pitch of the protruding tip portion that are different from the spiral pitch are different timings from the spiral blades of the toner conveying member. The deformation stress generated on the free end region side where one projecting tip (group) exists is reduced or eliminated at the notch, and the other projecting tip (group) adjacent to the other projecting tip (group) It becomes difficult to be transmitted to the existing free end region side. As a result, the swinging motions of the portions of the sheet-like elastic member that are divided on both sides are different in timing and are not interfered with each other and are performed independently. As a result, the load caused by the reaction force of the elastic member applied to the toner conveying member is more accurately dispersed and further reduced.
[0019]
The toner conveying device of the present invention is most effective when applied as a toner conveying device for conveying the toner removed by the cleaning member (blade, rotating brush, etc.) of the cleaning device in the image forming apparatus to the toner recovery unit. However, the present invention is not limited to this, and the present invention can be similarly applied to a toner transport device that is required to transport toner satisfactorily without aggregating and solidifying the toner. For example, the present invention can be applied as a toner transport device in a toner supply device from a toner storage container (such as a hopper or a toner cartridge).
[0020]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
1 and 2 show a color image forming apparatus according to Embodiment 1 of the present invention. FIG. 1 is a schematic diagram showing the overall configuration of the color image forming apparatus, and FIG.
[0021]
This color image forming apparatus includes four image forming units 10Y, 10M, 10C, and 10K that exclusively form toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K). The four color toner images formed in each of the image forming units 10 (Y, M, C, K) are primarily transferred so as to be superimposed on the surface of the intermediate transfer belt 20, and then the intermediate transfer belt. This is a color image forming apparatus capable of forming a so-called full-color image by performing secondary transfer from 20 to a recording paper P as a recording material. In addition, this image forming apparatus operates only a part of the four image forming units 10 (Y, M, C, K), for example, the black image forming unit 10K, so that a black and white image or the like can be obtained. It is also possible to form a single color image or a mixed color image.
[0022]
Each of the image forming units 10 forms each of the four color toner images by an electrophotographic process, and is in a horizontal state at a position on the lower side of the intermediate transfer belt 20 in the substantially central portion of the apparatus main body 1. They are arranged at intervals. Each of the image forming units 10 basically has a photosensitive drum 11 in which an organic photosensitive layer or the like is formed on the outer peripheral surface of a drum base that is rotationally driven in a direction indicated by an arrow at a predetermined speed, and the photosensitive drum 11. A charging roll 12 that uniformly charges the surface of the photosensitive drum 11, an exposure device 13 as a latent image forming device that forms an electrostatic latent image by exposing the surface of the charged photosensitive drum 11 to light according to image information, A developing device 14 that develops the electrostatic latent image with a developer of a predetermined color, a primary transfer roll 15 that electrostatically transfers a toner image formed by the development to the intermediate transfer belt 20, and a photosensitive drum 11. A blade-type drum cleaning device 16 for cleaning the surface is similarly provided.
[0023]
Among these, the exposure device 13 is housed in a housing sealed box 17 disposed on the lower side of the four image forming units 10, and is converted into image signals separated for each color from four semiconductor lasers (not shown). Laser beams LB-Y, LB-M, LB-C, and LB-K emitted in response to the rotary polygon mirror 18 through a predetermined optical system (lens or the like) are deflected and scanned, and then a plurality of unillustrated ones. Scanning exposure is performed obliquely from below on the respective photosensitive drums 11 facing each other through a single reflection mirror. Reference numeral 17a in the figure denotes a light output surface portion provided with a transparent glass surface for transmitting and emitting each laser beam LB from the inside of the housing sealed box 17 toward the photosensitive drum 11 of each image forming unit 10.
[0024]
Each developing device 14 uses a two-component developer containing a negatively charged non-magnetic toner and a magnetic carrier as the developer G. As shown in FIG. The developer G is accommodated in the accommodation / circulation conveyance path 41 and is agitated and conveyed by two developer agitating and conveying members (for example, augers) 42 and 43 that rotate in a parallel state. The toner is supplied to a developing roll 45 that is rotationally driven to an opening 44 that faces the photosensitive drum 11. Further, a primary transfer bias having a polarity opposite to the charging polarity of the toner image on the photosensitive drum 11 is applied to the primary transfer roll 15 from a bias power supply device (not shown).
[0025]
In each of the image forming units 10, after the surface of the photosensitive drum 11 rotating in the direction of the arrow is uniformly charged by the charging roll 12, the image signal is color-separated from the exposure device 13 on the charged surface. The electrostatic latent image is written by scanning and exposing the laser beam LB corresponding to the light through the light exit surface portion 17a, and then the latent image is developed with the toner T of the developer G supplied from the developing device 14. Thus, a toner image of a predetermined color is formed, and finally, the toner image is sequentially primary-transferred onto the surface of the intermediate transfer belt 20 passing between the photosensitive drum 11 and the primary transfer roll 15. The surface of the photosensitive drum 11 after the primary transfer is cleaned by removing residual toner and the like by the blade of the drum cleaning device 16.
[0026]
Next, the intermediate transfer belt 20 has an endless shape having a two-layer structure in which a surface layer such as silicone rubber is laminated on a belt base material such as a polyimide film containing a conductive material and the like and adjusted in volume resistivity. A belt, which is stretched around a drive roll 21, a backup roll 22 of a secondary transfer unit, and a plurality of driven rolls 23, 24,... And the photosensitive of each image forming unit 10 between the driven rolls 23, 24. The drums 11 are arranged so as to be in contact with the drums 11, respectively, and are rotated in the direction of arrow B by the rotational power of the drive roll 21.
[0027]
Around the intermediate transfer belt 20, a secondary transfer roll 25 is disposed that presses the intermediate transfer belt 20 against the backup roll 22 to form a pressure contact area of the secondary transfer portion. A power supply member 27 for supplying a secondary transfer bias having the same polarity as the charging polarity of the toner image on the intermediate transfer belt 20 from a bias power supply device (not shown) to the conductive shaft of the backup roll 22 is provided. It arrange | positions so that it may contact. Further, a blade type belt cleaning device 26 for cleaning the surface of the belt 20 is disposed at a position facing the drive roll 21 of the intermediate transfer belt 20.
[0028]
The toner image (multiple) transferred to the intermediate transfer belt 20 is conveyed to a secondary transfer portion facing the secondary transfer roll 25 arranged to face the backup roll 22 as the belt 20 rotates. Is done. In the secondary transfer unit, the toner image on the intermediate transfer belt 20 is sent out from the paper storage tray 30 disposed below the exposure device 13 in accordance with the image formation of the toner image and the secondary transfer timing. Electrostatic secondary transfer is performed on the recording paper P having a predetermined size that is fed by the mechanism 31 and transported to the secondary transfer section through the paper transport path on which the registration roll 32 and the like are arranged. The surface of the intermediate transfer belt 20 after the secondary transfer is cleaned by removing residual toner and the like by the blade of the belt cleaning device 26. A one-dot chain line in FIG.
[0029]
In addition, the recording paper P on which the toner image is transferred from the intermediate transfer belt 20 is naturally peeled off from the intermediate transfer belt 20 portion when passing through the secondary transfer portion, and then pressed with the heating roll 36 in the fixing device 35. A member (pressure pad, pressure roll, etc.) 37 is sent so as to pass through the pressure contact area of the member 37 and subjected to heat fixing treatment. Is done. Through the above process, a desired full-color image or the like is formed on the recording paper P.
[0030]
In this color image forming apparatus, as shown in FIGS. 2 and 3, the photosensitive drum 11, the charging roll 12, and the drum cleaning device 16 in each image forming unit 10 (Y, M, C, K) are further provided. The drum cartridge 50 is integrated and can be detachably attached to the apparatus main body 1. In the figure, reference numeral 51 denotes a cartridge frame, 51a denotes a frame portion located on the front side of the apparatus, and 51b denotes a frame portion located on the rear side of the apparatus.
[0031]
In this color image forming apparatus, as shown in FIGS. 4 and 5, a toner collection box (not shown) removes the toner removed by the cleaning device 16 from the drum cleaning device 16 incorporated in the drum cartridge 50. A toner conveying device 70 to be described later is mounted.
[0032]
First, the drum cleaning device 16 has a bowl-shaped housing 60 whose side facing the photosensitive drum 11 is opened along the drum rotation axis direction, and a support frame plate 62 on the lower end side of the opening of the housing 60. The cleaning blade 61 attached in this manner and the seal member 63 attached to the upper end side of the housing 60 constitute the main part. Among these, the housing 60 is formed with an internal space (toner accommodating / conveying path portion 71) that accommodates toner surrounded by a substantially U-shaped wall surface. Further, the cleaning blade 61 is made of polyurethane rubber or the like, and is set so that the free tip portion thereof contacts the photosensitive drum 11 with a predetermined amount of biting. In the cleaning device 16, the toner on the photosensitive drum 11 is removed by the cleaning blade 61, and the removed toner is dropped and accommodated in the internal space of the housing 60.
[0033]
The toner conveying device 70 attached to the cleaning device 16 rotates in the space of the toner accommodating / conveying path 71 formed integrally with the housing 60 of the cleaning device and the toner accommodating / conveying path 71. The screw auger 74 including the rotating shaft 72 and the spiral blade 73 installed in this manner, and the toner breaker sheet 75 that periodically contacts the spiral blade 73 of the screw auger 74 are mainly provided.
[0034]
The toner accommodating / conveying path 71 has a substantially U-shaped cross-section surrounded by a semi-cylindrical wall surface 71a constituting a part of the internal space of the housing 60, and communicates with the groove 71b. It is comprised by the cylindrical pipe part 71c (FIG. 3) protrudingly formed from one end part. A discharge port (not shown) for discharging the conveyed toner toward the toner collection box is formed at the lower end of the end portion of the pipe portion 71c.
[0035]
The screw auger 74 forms a spiral blade 73 in a state in which the screw auger 74 is continuously wound in a spiral manner at a predetermined spiral pitch α around a rotation shaft 72 having a length substantially corresponding to the transport path length of the toner containing transport path portion 71. It is a thing. The spiral blade 73 is formed at a certain height from the peripheral surface of the rotating shaft 72. Both ends of the screw auger 74 are pivotally supported so as to be rotated by the groove 71b and the pipe 71c of the toner containing conveyance path 71. At this time, the outer peripheral portion 73a of the spiral blade 73 is supported in a state where it faces the cylindrical wall surface 71a and the like in the toner containing transport path portion 71 with a certain gap. The screw auger 74 has a gear 74a (FIGS. 3 and 7) attached to the end of the rotating shaft 72 opposite to the pipe portion 71c, and meshes the gear 74a with a rotation drive gear (not shown). By this, it rotates in a predetermined direction.
[0036]
The toner breaker sheet 75 is a sheet member (thickness of about 0.1 to 0.3 mm) such as a mylar film having a length substantially the same as the width in the longitudinal direction of the cleaning blade 61. In this example, as shown in FIG. 5 and FIG. 6, the upper end portion of the toner breaker sheet 75 is bent toward the screw auger 74 side, and the bent upper end side sheet portion is used as the free end 75a. The sheet portion on the lower end side is used as the base end portion 75b.
[0037]
At the free end 75a, a protruding tip 76 shaped so as to be interposed between the spiral blades 73 of the screw auger 74 is basically a reference pitch β (= α) corresponding to the spiral pitch α of the spiral blades 73. A plurality are formed. The protruding tip portion 76 is a substantially right triangle having a hypotenuse along the spiral direction (inclination direction) of the spiral blade 73 (the corner of the most distal portion is rounded). Thereby, the front-end | tip part of the free end 75a becomes the form by which the regular unevenness | corrugation which consists of the protrusion front-end | tip part 76 and the recessed part which exists between them was formed continuously.
[0038]
Such a toner breaker sheet 75 has a state in which the free end 75a thereof is substantially parallel to the rotating shaft 72 of the screw auger 74 (not only in the true parallel state but in a range in which a swinging motion described later can normally occur). The base end portion 75b of the housing 60 so that the protruding tip portion 76 of the free end 75a can periodically come into contact with the spiral blade 73 of the rotating screw auger 74. Etc. (in this example, the support frame plate 62) is fixed to a predetermined portion by a fixing means such as a double-sided tape or an adhesive. As a result, the protruding tip 76 of the free end 75a enters the space between the spiral blades 73 of the screw auger 74 (FIGS. 5 and 6).
[0039]
In particular, in the toner breaker sheet 75, as shown in FIG. 7, a part of the reference pitch β of the protruding tip 76 at the free end 75a is different from the spiral pitch α of the spiral blade 73 of the screw auger 74. γ. In this example, the portions having the different pitch γ are set so as to exist in a portion corresponding to approximately ¼ and a portion corresponding to approximately ¾ when the entire width of the toner breaker sheet 75 is divided into four equal parts. The pitch γ is set to a value larger than the helical pitch α (for example, γ = α + α / 2) at any part. As a result, the portion having the different pitch γ serves as a boundary between the central region E1 having a width of about ½ in the width direction (longitudinal direction) of the free end 75a and the end regions E2 and E3 located on both sides thereof. Will exist at least.
[0040]
Further, in the toner breaker sheet 75, preferably, as illustrated in FIGS. 7 to 9, a concave portion (a free end portion) between the projecting tip portions 76a and 76b formed at different pitches γ of the free end 75a. For example, a linear cut portion (line) 78 is formed. Incidentally, in this toner breaker sheet 75, cut portions 79 having a predetermined width and depth are formed in a plurality of concave portions (free end portions thereof) between the protruding tip portions 76 located at both ends thereof. .
[0041]
Hereinafter, the operation of the toner conveying device 70 having such a toner breaker sheet 75 will be described.
[0042]
First, when a series of image forming processes is started, the screw auger 74 rotates in a predetermined direction (arrow m direction). During the image forming process, the toner remaining on the photosensitive drum 11 after the primary transfer is removed by the cleaning blade 61 of the drum cleaning device 16 and is dropped and collected in the internal space of the housing 60 as described above. When the amount of toner is accommodated, the collected toner is also accommodated in the toner accommodating and conveying path 71 and comes into contact with the spiral blade 73 of the screw auger 74. Then, the toner is transported toward the pipe portion 71c side of the toner containing transport path by the transport force of the spiral blade 73 of the rotating screw auger 74.
[0043]
At this time, depending on the setting condition of the pitch γ and the like, the toner breaker sheet 75 rotates at a fixed time when all the protruding leading end portions 76 at the free end 75a rotate as shown in FIG. 10a. Since the screw auger 74 does not come into contact with the spiral blades 73 without being in contact with the blades, the entire sheet is kept flat. Here, the position of the sheet 75 in this flat state is defined as a reference position Q. FIG. 10 is an explanatory view showing each state of the free end 75a of the toner breaker sheet 75 when viewed from the direction of the arrow X shown in FIGS. 6 and 7, and a one-dot chain line 72a in the drawing is a rotating shaft 72 of the screw auger 74. The center line of is shown.
[0044]
Next, when the screw auger 74 is rotated by a predetermined angle in the direction of arrow m, the toner breaker sheet 75, as shown in FIG. 8, for example, has a plurality of protruding tip portions 76 (group) in the central region E1 of the free end 75a. Is in contact with the spiral blade 73 that moves as if moving forward in the toner conveyance direction (arrow f direction), and is pushed downward by the movement of the blade 73 (arrow d direction). The sheet center region E1 is displaced so as to descend. On the other hand, at this time, the plurality of projecting tip portions 76 (group) in the end region E2, 3 of the free end 75a are in a state existing between the blades without contacting the spiral blade 73. Regions E2 and 3 remain at the reference position Q. As a result, as shown in FIG. 10b, the free end 75a of the toner breaker sheet is in a state where only its central region E1 is pushed downward, while its end regions E2, 3 are The state is held at the reference position Q.
[0045]
Subsequently, when the screw auger 74 is further rotated by a predetermined angle in the direction of arrow m from the above state (FIGS. 8 and 10b), the toner breaker sheet 75 has an end region of its free end 75a as shown in FIG. Since a plurality of projecting tip portions 76 (group) in E 2 and 3 come into contact with the spiral blade 73 and are pushed down by the movement of the blade 73 (arrow d direction), the sheet end region E 2 The three parts are displaced so as to descend. On the other hand, at this time, the plurality of projecting tip portions 76 (group) in the central region E1 of the free end 75a are in a state existing between the blades without contacting the spiral blade 73. The three portions remain at the reference position Q. As a result, as shown in FIG. 10C, the free end 75a of the toner breaker sheet is in a state where only its end regions E2 and 3 central region E1 are pushed downward, while its center The region E1 is held at the reference position Q.
[0046]
Thereafter, when the screw auger 74 further rotates in the direction of the arrow m, the above-described processes (states) of the toner breaker sheet 75 are similarly repeated as long as the screw auger 74 rotates.
[0047]
As described above, the free end 75a of the toner breaker sheet 75 is shifted in timing between the central region E1 and the end regions E2 and E3 that are divided by a portion having a pitch γ different from the helical pitch α of the protruding tip 76. Then, the entire seat swings as if it is wavy. In this example, since the pitch γ is set as “γ = α + α / 2”, the lowering timing (phase) of the central region E1 and the end regions E2 and E3 is shifted by about 180 °.
[0048]
Since the toner breaking sheet 75 swings in the vicinity of the screw auger 74 in this way, the toner is swung, so that the toner lump that is likely to aggregate and harden in the toner accommodating and conveying path 71 is broken. Accordingly, the toner is favorably conveyed by the screw auger 74 without being solidified.
[0049]
In addition, as described above, the pitch β of the plurality of protruding tip portions 76 formed on the free end 75a of the toner breaker sheet 75 is divided on both sides with a portion (pitch γ portion) that is different from the spiral pitch α. The existing projecting tip portions (groups) come into contact with the spiral blades 73 of the screw auger 74 at relatively different timings (cycles). As a result, the load caused by the reaction force applied to the auger 74 when the protruding tip 76 of the free end 75a of the toner breaker sheet contacts the spiral blade 73 of the rotating screw auger 74 is dispersed and reduced.
[0050]
In particular, in this example, since the portion of the projecting leading end portion 76 with the pitch γ is set to be present at least at the end portions of the central region E1 in the width direction of the free end 75a of the toner breaking sheet, the rotating screw auger The load caused by the reaction force from the central region E1 in the width direction of the free end 75a, which is the largest among the loads caused by the reaction force of the toner breaker sheet 75 applied to 74, can be effectively reduced.
[0051]
Further, when the linear cut portion 78 is formed in the concave portion having the pitch γ of the protruding tip portion 76 of the toner breaker sheet 75, the central region E1 and the end region E2 at the free end of the sheet 75 are formed. When E3 moves down and swings at different timings, the central region E1 and the end regions E2 and E3 of the free end are divided by the cut portions 78 and are clearly independent without interfering with each other. Oscillates in the state. Specifically, the region E1 (or E2, E3) descending in the direction of the arrow d shown in FIG. 10 (b, c) and the other regions E2, E3 (E1) are the cut portions 7. 8 With the dotted line portion indicated by the pitch γ corresponding to the portion where the is formed as a boundary, the twisted portion is not slack and swings in a more clearly separated state. Further, since the cut portions 79 are formed in the end regions E2 and E3 of the free end 75a of the toner breaker sheet 75, the load applied to both ends in the longitudinal direction of the sheet 75 when the toner breaker sheet 75 swings. Can be reduced.
[0052]
As a result, the screw auger 74 (strictly, the rotating shaft 72) is deformed so as to be bent and is not easily decentered, and the spiral blade 73 of the screw auger 74 is formed on the portion of the toner conveyance path 71, mainly on the wall surface 71a. Collisions can be reliably avoided.
[0053]
Therefore, in the toner conveying device 70, noise due to the screw auger 74 colliding with the wall surface 71 a of the toner conveying path 71 does not occur. In addition, in this case, the toner breaking sheet 75 swings as described above, and it is not necessary to reduce the thickness of the sheet, so that the toner breaking effect by the sheet 75 is not reduced. As a result, the toner removed by the cleaning device 16 is smoothly conveyed from the groove 71b of the toner containing sales channel 71 to the pipe 71c side by the conveying force of the screw auger 74.
[0054]
[Other embodiments]
In the first embodiment, the case where the portion of the pitch γ that is different from the spiral pitch α is set as “γ = α + α / 2” is exemplified, but the present invention is not limited to this. For example, γ = α + α / 4 May be set. In this case, the lowering timing (phase) of the central region E1 and the end regions E2 and E3 at the free end 75a of the toner breaker sheet is shifted by about 90 °. Further, the pitch γ may be set so that the shift of the lowering timing of the center region E1 and the end regions E2 and E3 is random.
[0055]
Further, the portion of the pitch γ that is different from the helical pitch α need not be limited to two in the width direction of the free end 75a of the toner breaking sheet, and may be one or three or more. I do not care. Of course, the toner breaker sheet 75 may be of a form that is not bent.
[0056]
【The invention's effect】
As described above, according to the present invention, noise caused by periodic contact between the sheet-like elastic member and the toner conveying member (spiral blade) can be reduced without reducing the toner breaking effect of the sheet-like elastic member. Occurrence can be prevented. As a result, it is possible to perform smooth toner conveyance without generating noise.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a color image forming apparatus according to a first embodiment.
FIG. 2 is a cross-sectional view of a main part showing a configuration of an image forming unit and its peripheral part.
FIG. 3 is a perspective view showing a drum cartridge.
4 is a partial cross-sectional view taken along the line VI-VI in FIG. 4;
FIG. 5 is a perspective view showing a cleaning device and a toner conveying device.
FIG. 6 is a perspective view showing a usage state of a screw auger and a toner breaking sheet.
FIG. 7 is an explanatory diagram showing a pitch configuration of a protruding tip portion at a free end of a toner breaking sheet.
FIG. 8 is an explanatory diagram showing an operating state of the free end of the toner breaking sheet (when only the central region is lowered).
FIG. 9 is an explanatory diagram showing an operating state of the free end of the toner breaking sheet (when only both end regions are lowered).
FIG. 10 is an explanatory view showing a swinging motion state of a free end of a toner breaking sheet.
FIG. 11 is a schematic cross-sectional view showing a conventional cleaning device and a toner conveying device.
FIGS. 12A and 12B show a configuration of a toner conveying member and a sheet-like elastic member in the toner conveying apparatus of FIG. 12, wherein FIG.
13 is an explanatory diagram illustrating an operation state of a sheet-like elastic member in the toner conveyance device of FIG.
FIG. 14 is a conceptual diagram illustrating a generation mechanism of noise generated in a conventional toner conveying device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 70 ... Toner conveyance apparatus, 71 ... Toner accommodation conveyance path part (conveyance path part), 72 ... Rotating shaft, 73 ... Spiral blade | wing, 75 ... Toner breaking sheet (sheet-like elastic member), 75a ... Free end, E1 ... Center Area, 76 ... projecting tip, 78 ... notch, α ... spiral pitch, β ... reference pitch, γ ... pitch different from spiral pitch.

Claims (4)

A toner conveying member in which a toner conveying member is formed; a toner conveying member formed with a spiral blade wound around a rotating shaft rotating in a space of the conveying channel at a predetermined helical pitch; and a spiral blade of the toner conveying member The projecting tip portion that can be interposed between the two has a free end formed in plural at the same pitch as the spiral pitch of the spiral blade, and the free end faces the rotation axis of the toner conveying member substantially in parallel with the free end. In a toner conveying device comprising a sheet-like elastic member fixedly installed in such a manner that a protruding tip portion of a free end can periodically come into contact with a spiral blade of a rotating toner conveying member,
A part of the pitch of the protruding tip portion at the free end of the sheet-like elastic member is set to a pitch different from the spiral pitch of the spiral blade of the toner conveying member, and the portion of the different pitch is a central region in the width direction of the free end. A toner conveying device characterized in that the toner conveying device is present at least at portions that are both ends of the toner. The toner conveying device according to claim 1, wherein a cut portion is formed in a concave portion formed between protruding tip portions formed at a pitch different from the helical pitch . The toner conveying device according to claim 1 , wherein a cut portion is formed between projecting tip portions formed at the portions to be the both end portions . The sheet-like elastic member is a portion in which the free end is bent toward the toner conveying member, and is attached in a state in which a portion other than the free end is fixed. The toner conveying device according to 1.

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