JP2008046190A - Powder conveying device, process unit, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder conveying device capable of maintaining stable powder conveying ability by preventing powder from being flocculated and stuck on the inner wall surface of a housing while securing a gap between a conveying member which conveys powder by rotation and the inner wall surface of the housing over a long term. <P>SOLUTION: The powder conveying device includes: the conveying member 44 having a plurality of fins 52 fixed to be spaced on a rotary shaft 50, and rotating to convey the powder in a shaft direction by the conveying action of the fin 52; and the housing 42 in which the conveying member 44 is housed, and also is equipped with: a flocculation preventing member 54 laid between the fins 52 proximately to the inner wall surface 46 of the housing 42 on the outer periphery part of the fin 52 of the conveying member 44; and a vibration generating part 58 vibrating the flocculation preventing member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a powder conveying apparatus applied to a copying machine, a printer, a facsimile machine, or a complex machine of these, a process unit using the same, and an image forming apparatus.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus is provided with a powder conveying device for conveying toner that is powder in a developing device and a waste toner collecting device. As the powder conveying device, a conveying member having a plurality of fins fixed in an axial direction on a rotating shaft is provided in the housing, and the toner is pivoted by the conveying action of the fins by rotating the conveying member. Those that are transported in one direction are widely used.

  When the toner is conveyed by rotating the conveying member, a gap is formed between the fin and the inner surface of the housing, and the toner gradually aggregates in the gap, and the toner aggregate eventually rises. The outer periphery of the rotating fin comes into contact. In such a case, the toner conveyance performance deteriorates and the conveyance path is clogged.

  On the other hand, when the gap is not provided between the fin and the inner surface of the housing, the outer peripheral edge of the fin comes into contact with the inner surface of the housing during rotation of the conveying member, so that the rotational load on the conveying member increases. As a result, not only a large torque drive source is required, but also the toner particle shape is destroyed by being sandwiched between the outer periphery of the fin and the inner surface of the housing. It is indispensable to provide a gap between them.

  Therefore, in the toner stirring / supplying member common to the transporting member in the function of transporting or supplying the toner by rotating, an elastic body such as a polyester film is fixed to the outer periphery of the rotating shaft, and the toner stirring / supplying member rotates. A configuration in which the tip of the elastic body is sometimes brought into sliding contact with the inner wall surface of the housing to prevent the toner from adhering to the inner wall surface of the housing facing the toner agitation supply member is disclosed in, for example, Patent Document 1 is disclosed.

Japanese Patent Laid-Open No. 10-20668

  If the inner surface of the housing is slidably contacted with the elastic body as described above, the driving load can be reduced as compared with the case where the outer peripheral portion of the fin of the conveying member is in contact with the inner surface of the housing, but in consideration of the recent environment. From the viewpoint of low torque design, there is a sense of lack of effectiveness, and when low-temperature fixing toner aiming at energy saving or small particle size toner aiming at high image quality is used, sliding contact between the elastic body and the inner surface of the housing It will also cause deterioration of toner performance.

  Therefore, the present invention is stable by preventing agglomeration and adhesion of the powder on the inner wall surface of the housing while ensuring a gap over a long period between the conveying member that conveys the powder by rotation and the inner wall surface of the housing. An object of the present invention is to provide a powder conveying apparatus capable of maintaining the powder conveying property, a process unit and an image forming apparatus using the same.

In order to achieve the above object, the powder conveying device of the present invention has a plurality of fins fixed at intervals on a rotating shaft, and the powder is axially moved by the conveying action of the fins by rotating. In a powder conveying device comprising a conveying member for conveying the toner and a housing for accommodating the conveying member,
The outer peripheral part of the said fin of the said conveyance member is provided with the aggregation prevention member erected between the said fins so that it may adjoin to the inner wall face of the said housing, and the vibration generation part which produces a vibration in the said aggregation prevention member It is characterized by.

  In the powder conveyance device of the present invention, the aggregation preventing member may be an elongated member that is installed between the fins. In this case, the aggregation preventing member may be fixed to all the fins, or may be fixed to every predetermined number of fins.

  Further, in the powder conveying device of the present invention, both ends of the aggregation preventing member are respectively fixed to fixing members provided on the rotating shaft on the end side further than the fins on both ends of the conveying member. May be.

  In the powder conveyance device of the present invention, the aggregation preventing member may be made of an elastic body, and may be temporarily caught by a protrusion provided on the inner wall surface of the housing when the conveyance member rotates. .

  In the powder conveying apparatus of the present invention, when the circumferential length of the conveying member is L, and the total diameter of one or a plurality of the aggregation preventing members is M, L × 0.01 <M ≦ L × It is preferable to satisfy the relationship of 0.5.

  In the powder conveyance device of the present invention, the powder may be replenishment toner replenished to the developing device or recovered toner recovered from the image bearing member by the cleaning device.

  The present invention also provides a process unit including the powder conveying device and detachable from the image forming apparatus.

  The present invention also provides an image forming apparatus including the powder device or the process unit.

  According to the powder conveying device of the present invention, the aggregation preventing member is provided close to the inner wall surface of the housing (that is, in a non-contact state). Preventing powder agglomerates from sticking and growing by pulverizing the agglomeration of powder on the inner wall surface of the housing by the agglomeration prevention member that is not slid on the wall surface and vibrated by the vibration generating portion Can do. As a result, the gap between the conveying member and the inner wall surface of the housing can be prevented from being filled with powder aggregates, and the driving load of the conveying member can be stably maintained in a low torque state and stable. The powder conveyance performance can be stably maintained over a long period of time. Further, since the aggregation preventing member does not slide on the inner wall surface of the housing when the conveying member rotates, the powder performance is not deteriorated due to the sliding contact.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a schematic configuration of an image forming apparatus 10 according to the present invention. The image forming apparatus 10 includes a scanner unit 14 on the upper part of the apparatus main body 12, and in addition to a printer function for performing an image forming operation based on image data input from an external apparatus, a document read by the scanner unit 12 It also has a copy function for copying images.

  An intermediate transfer belt 16 that is stretched over two rollers 15a and 15b and is driven to rotate in the direction of arrow A is disposed at a substantially central portion of the apparatus main body 12. Under the intermediate transfer belt 16, four process units 18 corresponding to yellow, cyan, magenta, and black toners are arranged horizontally in order from the left side.

  Each process unit 18 includes a cylindrical photosensitive member (image carrier) 20 that contacts the intermediate transfer belt 16, a charging device 22 that uniformly charges the surface of the photosensitive member 20, and a surface of the uniformly charged photosensitive member 20. A developing device 26 that develops an electrostatic latent image formed by laser exposure with toner to form a toner image, and collects toner remaining on the photoreceptor 20 after the toner image is primarily transferred onto the intermediate transfer belt 16. And a cleaning device 24. Each process unit 18 is detachable from the apparatus main body 12.

  The secondary transfer roller 26 is disposed in contact with the outer surface of the intermediate transfer belt 16 supported from the inside by the roller 15b, and the contact portion between the intermediate transfer belt 16 and the secondary transfer roller 26 is the secondary. It is a transcription part. A fixing device 28 composed of a pair of rollers is disposed above the intermediate transfer belt 16.

  A sheet feeding unit 30 for stacking and storing sheets is provided at the lower part of the apparatus main body 12. The sheets fed one by one from the sheet feeding unit 30 are conveyed upward by the conveyance roller pair 32, and after passing the toner image when passing through the secondary transfer unit, pass through the nip portion of the fixing device 28. When the toner image is heated and fixed, the toner image is discharged onto the paper discharge tray 34.

  FIG. 2 shows a schematic configuration of a cleaning device 24 including a toner conveying device which is an embodiment of the powder conveying device according to the present invention. The cleaning device 24 has a cleaning blade 40 having one end abutted against the surface of the photoconductor 20 that is rotationally driven in the direction of arrow C, and a housing having an inner space to which the other end of the cleaning blade 40 is fixed. Housing 42, a conveying member 44 disposed in the housing 42 so as to be able to be driven to rotate, and a seal member 45 attached to an upper portion of the housing 42 facing the photosensitive member 20.

  The seal member 45 is made of, for example, a soft resin film, and a tip portion thereof is in contact with the photoconductor 20. The seal member 45 allows the toner on the photoconductor 20 to pass due to its flexibility, but prevents the collected toner that has been scraped off by the cleaning blade 40 and accumulated on the front end portion thereof from leaking out of the cleaning device 24. It is to make.

  The conveying member 44 is provided in the lower part of the housing 42 with a predetermined gap 48 between the conveying member 44 and the inner wall surface 46 of the housing 42. In addition, in the conveying member 44, for example, a plurality of elliptical fins 52 are fixed on a rotating shaft 50 having a round bar shape, for example, at predetermined intervals in the axial direction. As shown in FIG. 3, the fins 52 are provided so as to be inclined in a fixed direction with respect to the rotation shaft 50.

  As shown in FIGS. 2 and 3, at least one piece (in this embodiment, the diameter is extended) between the fins 52 on the outer peripheral portion of the fins 52 in the conveying member 44 in a state of being close to the inner wall surface 46 of the housing 42. Two aggregation preventing members (aggregation preventing members) 54 are provided so as to extend in the axial direction at positions opposite to each other in the direction. The aggregation preventing member 54 is, for example, an elongated rod-like member having a circular cross section, and is preferably made of an elastic body having rubber properties or stretchability. As described above, the aggregation preventing member 54 is provided close to the inner wall surface 46 of the housing 42, so that it does not come into contact with the inner wall surface 46 of the housing 42 when the transport member 44 is driven to rotate in the direction of arrow B. It has become.

  As shown in FIG. 3A, both ends of the aggregation preventing member 54 are, for example, rod-shaped or disk-shaped 2 provided on the rotating shaft 50 on the end side further than the fins 52 on both ends of the conveying member 44. The two fixing members 56 are respectively fixed. In this case, the width of the aggregation preventing member corresponding to the width between the fixing members 56 is substantially equal to the width of the internal space of the housing 42 along the axial direction of the conveying member 44. Over the full width of 42. However, as shown in FIG. 3B, even if both ends of the aggregation preventing member 54 are fixed to the fins 52 on both ends of the conveying member 44, respectively, the same effect as in the case shown in FIG. Thus, there is an advantage that the fixing member 56 can be omitted.

  On the other hand, as shown in FIG. 2, on the inner wall surface of the housing 42, a plurality of protrusions (vibration generating portions) 58 are provided so as to protrude, for example, in a straight line at positions corresponding to the fins 52. The protrusion height of the protrusion 58 is set such that the aggregation preventing member 54 is temporarily caught when the conveying member 44 is rotated. In addition, the protrusion 58 may have flexibility so that the aggregation preventing member 54 may be bent by a force that is temporarily hooked and acts in the lateral direction.

Next, the operation of the cleaning device 24 configured as described above will be described.
In the cleaning device 24, the toner remaining on the surface of the rotationally driven photoconductor 20 is scraped off and collected by the cleaning blade 40. The collected toner falls toward the bottom in the housing 42. At this time, the conveying member 44 is driven to rotate in the direction of arrow B, and is conveyed in one direction along the axial direction by the conveying action of each fin 52 and discharged from the housing 42 through a discharge port (not shown).

  Generally, the collected toner or waste toner collected by the cleaning device 24 is considerably less fluid than the new toner before durability because various fine particles formulated as external additives are peeled off. And has the property of being easily aggregated. For this reason, as the image forming operation is repeated, the toner aggregates and accumulates on the inner wall surface 46 of the housing, particularly in the gap 48 between the conveying member 44 and the inner wall surface 46 of the housing. 48 is filled with toner aggregates. In this case, the toner conveying performance is deteriorated and the conveying path is clogged at worst, or the gap 48 is provided for the purpose of reducing the torque of the driving load of the conveying member 44, but the conveying member 44 The driving load becomes very large compared to the beginning, and the rotation of the photoconductor 20 driven by the same driving source also has an influence on unevenness of speed and the like, causing image noise.

  Therefore, in order to cope with this problem, the cleaning device 24 in the present embodiment is provided with an aggregation preventing member 54. As shown in FIGS. 4A to 4C, the aggregation preventing member 54 is temporarily hooked on the tip of the protrusion 58 protruding from the inner wall surface 46 of the housing when the conveying member 44 is rotated, and is then extended. Deviate from. When it comes off, the aggregation preventing member 44 vibrates, for example, as a wave due to the reaction of the elongation. The vibrating aggregation preventing member 44 pulverizes the toner that aggregates on the inner wall surface 46 of the housing in the gap 48, and can be conveyed by the conveying member 44.

  As described above, according to the cleaning device 24 of the present embodiment, the aggregation preventing member 54 is provided close to the inner wall surface of the housing in a non-contact state. 54 is not in sliding contact with the inner wall surface 46 of the housing, and the aggregation of the toner on the inner wall surface 46 of the housing is pulverized by the vibrating aggregation preventing member 54 so that the powder aggregate is fixed on the inner wall surface 46 of the housing. It can be prevented from growing. Accordingly, the gap 48 between the conveying member 44 and the housing inner wall surface 46 can be prevented from being filled with toner aggregates, and the driving load of the conveying member 44 can be stably maintained in a low torque state. Thus, stable toner conveyance performance can be stably maintained over a long period of time. Further, since the aggregation preventing member 54 does not slide on the housing inner wall surface 46 when the transport member 44 rotates, the toner performance does not deteriorate due to the sliding contact.

  In this embodiment, when the circumferential length of the conveying member 44 is L and the total of the diameters of the aggregation preventing member 54 (or the maximum length substantially along the circumferential direction of the conveying member 44) is M, L × 0. It is preferable that the relationship of 01 <M ≦ L × 0.5 is satisfied. This is because the ratio of the total diameter of the aggregation preventing member 54 to the circumferential length L of the conveying member 44 is changed to evaluate the original toner conveying performance and the stay preventing function of the conveying member 44. When the ratio of M is less than 1%, the retention preventing function cannot be sufficiently achieved. On the other hand, when the ratio exceeds 50%, the original toner transport performance of the transport member 44 is impaired. It is based on. Incidentally, as a specific example of the present embodiment, the circumferential length L of the conveying member 44 is 50 mm, the total diameter M of the two aggregation preventing members 54 (1 mm) is 2 mm, and the ratio is 4%. .

  By the way, in the cleaning device 24 or the powder conveying device and the process unit according to the present invention, various changes and improvements can be made, and specific examples are listed below.

  In the embodiment, the rod-shaped aggregation preventing member 54 having a circular cross section is used. However, the aggregation preventing member 54 may have other cross-sectional shapes or other forms. For example, the anti-aggregation member 54 may have an elliptical cross section as shown in FIG. 5, the anti-coagulation member 54 may have a square cross section as shown in FIG. The aggregation preventing member 54 may be configured by arranging a plurality of thin fibrous members adjacent to each other, or a metal coil spring may be used as the aggregation preventing member 54 as shown in FIG.

  In the above embodiment, the aggregation preventing member 54 made of an elastic body is vibrated by temporarily hooking it on the protrusion. However, as shown in FIG. 9, an AC voltage is generated in the aggregation preventing member 54 having conductivity. You may make it vibrate by applying an alternating voltage from a source (vibration generation part). Further, the aggregation preventing member 54 is made of a magnetic material, or a magnetic body is attached to a part of the aggregation preventing member 54 and a magnet (vibration generating portion) is disposed in place of the protrusion 58, and the aggregation preventing member 54 is magnetically affected. It is also possible to bend and vibrate by the reaction.

  In general, the powder tends to agglomerate at the downstream side in the powder conveyance direction. Therefore, the amplitude and vibration frequency of the aggregation preventing member may be configured to increase toward the downstream side. It is effective in preventing body retention.

  In addition, when the torque of the further conveying member is reduced, even the above-described vibration of the anti-aggregation member is expected to lead to image noise. In such a case, the anti-aggregation member may not be vibrated at the time of image formation, but may be configured or controlled so as to vibrate only during non-image forming operations (for example, between images or before / after processing).

  In order to effectively prevent the powder from adhering to the aggregation preventing member, the surface of the aggregation preventing member may be coated with, for example, PTFE.

  Further, the powder conveyed by the powder conveying device according to the present invention may be not only the recovered toner collected from the image carrier such as the photosensitive member by the cleaning device but also the replenishing toner replenished to the developing device. .

  In the above embodiment, the process unit 18 has been described as including the photosensitive member 20, the charging device 22, the developing device 26, and the cleaning device 24. However, the process unit according to the present invention includes, for example, the photosensitive member 18 and the toner transport. It only needs to include at least a cleaning device or a developing device having the device.

  Further, the image forming apparatus according to the present invention may be any of a monochrome / color copying machine, a printer, a facsimile machine, or a complex machine of these.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram of a cleaning device according to an embodiment of the present invention. (A) is a side view of the conveyance member which fixed the both ends of the aggregation prevention member with the fixing member, (b) is a side view of the conveyance member which fixed the both ends of the aggregation prevention member to the fin, respectively. (A)-(c) is a figure which shows a mode that a vibration generate | occur | produces in an anti-aggregation member when the anti-aggregation member is temporarily caught on a protrusion and then comes off. The figure which shows the modification of an aggregation prevention member. The figure which shows another modification of an aggregation prevention member. The figure which shows another modification of an aggregation prevention member. The figure which shows another modification of the aggregation preventing member. FIG. 2 is a schematic configuration diagram of a cleaning device that vibrates an aggregation preventing member by applying an alternating voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 18 ... Process unit 20 ... Photoconductor (image carrier)
24 ... Cleaning device 26 ... Developing device 40 ... Cleaning blade 42 ... Housing 44 ... Conveying member 46 ... Housing inner wall surface 50 ... Rotating shaft 52 ... Fin 54 ... Aggregation preventing member 58 ... Protrusion (vibration generating portion)

Claims (8)

A plurality of fins fixed at intervals on a rotating shaft, a conveying member for conveying powder in the axial direction by the conveying action of the fins by rotating; and a housing for accommodating the conveying member; In the powder conveying apparatus provided with
The outer peripheral part of the fin of the conveying member is provided with an anti-coagulation member laid between the fins so as to be close to the inner wall surface of the housing, and a vibration generating unit that generates vibration in the anti-aggregation member. A powder conveying device.   The powder conveying apparatus according to claim 1, wherein the aggregation preventing member is an elongated member that is installed between the fins.   The both ends of the anti-aggregation member are respectively fixed to fixing members provided on the rotating shaft on the end side further than the fins on both end sides of the conveying member. The powder conveying apparatus described in 1.   4. The coagulation preventing member is made of an elastic body, and is temporarily caught by a protrusion provided on an inner wall surface of the housing when the transport member is rotated. The powder conveying apparatus described in 1.   When the circumferential length of the conveying member is L and the total diameter of one or a plurality of the aggregation preventing members is M, the relationship of L × 0.01 <M ≦ L × 0.5 is satisfied. The powder conveying apparatus according to any one of claims 1 to 4.   6. The powder transport according to claim 1, wherein the powder is a replenishing toner replenished to the developing device or a collected toner collected from the image carrier by a cleaning device. apparatus.   A process unit comprising the powder conveyance device according to claim 1 and detachable from an image forming apparatus.   An image forming apparatus comprising the powder device according to claim 1 or the process unit according to claim 7.

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