JP2008158170A - Cleaning device and image forming apparatus incorporating it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device and an image forming apparatus incorporating it capable of maintaining the stabilized toner carry capability by effectively preventing the waste toner from coagulating even when increasing the speed in carrying the waste toner. <P>SOLUTION: The device has a scraper sheet 40 disposed in contact with the side of the spiral carrier 23 to prevent the toner from coagulating or caking. Further, many scraper pieces 40a are formed on the free end of the scraper 40 and they are positioned with spacing P1 larger than the pitch P of the spiral fin 23b but not multiples of it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning device that removes untransferred toner remaining on the surface of an image carrier and an image forming apparatus including the same.

  In an image forming apparatus using an electrophotographic system such as a copying machine, a printer, or a FAX, a powder developer (hereinafter referred to as toner) is mainly used, and an electrostatic image formed on an image carrier such as a photosensitive drum. In general, the latent image is visualized with toner in the developing device, and the toner image is transferred onto a recording medium, and then a fixing process is performed. In such an image forming apparatus, a cleaning device for removing residual toner on the surface of the photosensitive drum is mounted.

  FIG. 7 is a plan sectional view showing an example of the configuration of a conventional cleaning device. The cleaning device 7 includes a rubbing roller 21, a cleaning blade 22, and a conveyance spiral 23 that are in line contact with each other in the longitudinal direction of the photosensitive drum 3 by a spring (not shown) in a housing 7 a. The transport spiral 23 has a configuration in which a spiral blade 23b is provided around the rotation shaft 23a, and is rotatably supported in the housing 7a together with the rubbing roller 21. The rubbing roller 21 is directly connected to the motor 24, and the conveying spiral 23 is connected to the motor 24 via gears 25 and 26, and is driven to rotate at a predetermined speed.

  Residual toner scraped from the surface of the photosensitive drum 3 by the rubbing roller 21 or the cleaning blade 22 falls due to gravity and gradually accumulates in the housing 7a as waste toner. Then, when the conveying spiral 23 rotates in the direction of arrow A in the figure, the toner in the housing 7a is sequentially conveyed in the direction of arrow B, and is discharged from the toner discharge port 27 provided on the bottom surface of the housing 7a to the outside of the apparatus. It is stored in the waste bottle 28. When the disposal bottle 28 becomes full after printing a predetermined number of sheets, the user is notified and the disposal bottle 28 is discarded and replaced.

  In such a cleaning device, the waste toner collected from the drum surface becomes uneven in the degree of adhesion and particle size of the external additive due to mechanical stress, and further deteriorates in fluidity by mixing paper powder and the like. It is easy to solidify. For this reason, there is a problem in that the waste toner having lowered fluidity is solidified around the conveyance spiral 23 (for example, between the spiral wings 23b) and becomes a so-called blocking state, which makes conveyance difficult.

  In particular, in a cleaning device used in a vertical conveyance type image forming apparatus as disclosed in Patent Document 1, a cleaning blade, a cleaning roller, or the like is positioned at an upper portion of the photosensitive member and is formed on the photosensitive member side. Therefore, the waste toner scraped off from the surface of the photosensitive drum stays in the vicinity of the opening due to gravity and is likely to aggregate. When the aggregation is promoted and the waste toner is solidified, the waste toner scraped off by the toner removing unit cannot enter the cleaning device, and the toner flows backward from the seal portion to contaminate the sheet or the image forming apparatus. Further, the pressure of the agglomerated toner causes the tip of the cleaning blade to be deformed, creating a gap between the photosensitive drum and defective cleaning (toner slipping).

  Further, in the cleaning device described in Patent Document 1 disposed on the upper portion of the photosensitive member, a problem due to toner retention is particularly likely to occur. Therefore, it is necessary to transport waste toner inside the device to the outside as quickly as possible. Here, the toner conveying speed by the conveying spiral is related to the rotational speed of the conveying spiral and the shape of the conveying spiral. That is, the faster the conveyance spiral is rotated and the greater the distance (pitch) between adjacent spiral wings, the higher the conveyance speed.

  However, with the downsizing of the image forming apparatus, when the drive gear of the conveyance spiral is connected to the drive gear of the photosensitive drum so that the drive source is shared, if the rotation speed of the conveyance spiral is increased, the rotation unevenness of the spiral may occur. This adversely affects the rotation of the drum and causes image pitch unevenness and jitter, leading to a reduction in image quality. Further, even when the transport spiral and the photosensitive drum are driven separately, vibration accompanying the high-speed rotation of the transport spiral is transmitted to the photosensitive drum via the housing or the like, and there is a possibility that the same problem may occur. Therefore, in general, the pitch of the spirals of the transport spiral is set as wide as possible in order to increase the transport speed.

  On the other hand, as a method for preventing solidification of waste toner and improving the transport performance of the transport spiral, for example, in Patent Document 2, a scraping member formed of a flexible material is mounted around the transport spiral, and this scraping is performed. A method is disclosed in which solidification of waste toner below the transport spiral is suppressed by swinging the paying member up and down with the spiral blades of the transport spiral.

In recent years, in order to reduce the cost of the apparatus and improve the separability at the time of recycling, a low- and medium-speed machine has come to use a resin conveyance spiral. However, if the pitch of the spiral wings is increased in order to improve the transport performance, the bending rigidity of the transport spiral is lowered. Furthermore, when the technique of Patent Document 2 is adopted, if the width of the scraping member is increased in accordance with the pitch in order to efficiently prevent toner aggregation, a large force is required for swinging. Therefore, the load applied to the transport spiral is increased, and the resin-made transport spiral is curved, which may cause a problem that smooth rotation is hindered.
JP 2003-98924 A Japanese Unexamined Patent Publication No. 64-7088

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a cleaning device capable of effectively preventing solidification of waste toner and maintaining stable toner transport performance even when the waste toner transport speed is increased, and image formation provided with the same An object is to provide an apparatus.

  In order to achieve the above object, the present invention provides a housing disposed to have an opening on the image carrier side above the image carrier, and a toner that is disposed in the opening and scrapes off residual toner on the surface of the image carrier. In a cleaning apparatus comprising: a removing unit; and a conveying spiral in which a spiral blade for conveying toner scraped off from the surface of the image carrier disposed above the toner removing unit is formed around a rotation shaft. A plurality of scraping pieces formed of an elastic material that abuts on the side surface of the conveying spiral and swings are arranged, and the arrangement interval of each of the scraping pieces is wider than the pitch of the spiral wings and is a multiple of the pitch It is characterized by not.

  According to the present invention, in the cleaning device configured as described above, an interval between the scraping pieces is less than twice the pitch of the spiral wings.

  According to the present invention, in the cleaning device having the above-described configuration, the toner removing unit includes a cleaning blade provided on the downstream side in the rotation direction of the image carrier at the opening, and a cleaning blade provided on the upstream side with respect to the cleaning blade. And the free end of the scraping piece swings between the tip of the cleaning blade and the cleaning roller.

  According to the present invention, in the cleaning device having the above-described configuration, the cleaning roller functions as a rubbing roller by contacting the image carrier with toner.

  The present invention also provides an image forming apparatus equipped with the cleaning device having the above-described configuration.

  According to the first configuration of the present invention, by disposing a plurality of scraping pieces that loosen the waste toner by swinging and suppress aggregation and solidification and are wider than the pitch of the spiral blades and at intervals that are not a multiple of the pitch, The timing at which the spiral wing pushes up the scraping member is shifted and the force for swinging the scraping member is dispersed, and the load on the transport spiral is also reduced. Therefore, even when the pitch of the spiral wings is widened to increase the toner conveyance speed, it is possible to prevent the conveyance spiral from being bent.

  Further, according to the second configuration of the present invention, in the cleaning device of the first configuration, by setting the arrangement interval of each scraping piece to less than twice the pitch of the spiral wing, Since at least a part of the scraping pieces always overlap, the unraveling effect of the waste toner can be made uniform in the axial direction of the conveying spiral.

  According to the third configuration of the present invention, in the cleaning device having the first or second configuration, the toner removing unit is configured by the cleaning blade and a cleaning roller provided on the upstream side with respect to the cleaning blade. In addition, the toner staying between the tip of the cleaning blade and the cleaning roller can be efficiently loosened to suppress aggregation and solidification. As a result, it is possible to effectively prevent the toner removed from the image carrier from entering the cleaning device and leaking from the seal portion, or the solidified toner deforms the tip of the cleaning blade and causes the toner to slip through. can do.

  According to the fourth configuration of the present invention, in the cleaning device of the third configuration, when the cleaning roller functions as a rubbing roller, the toner staying around the rubbing roller using a scraping piece is removed. By preventing aggregation and solidification, the toner used for polishing the drum surface can be replaced efficiently, and the polishing effect is improved.

  Further, according to the fifth configuration of the present invention, by mounting the cleaning device having any one of the first to fourth configurations, the toner discharge efficiency is improved by suppressing the aggregation and solidification of the waste toner. Thus, the image forming apparatus can effectively prevent the occurrence of contamination and image defects inside the apparatus due to toner leakage and cleaning failure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an image forming apparatus equipped with a cleaning device of the present invention. The image forming apparatus (for example, a printer) 100 includes a photosensitive drum 3, a charging unit 4, an exposure unit (laser scanning unit) 5, a developing device 6, a cleaning device 7, a toner container 8, a transfer roller 9, a paper feeding mechanism 10, It includes a transport unit 11, a fixing device 12, a paper discharge unit 13, and the like.

  The photosensitive drum 3 is formed, for example, by laminating a photosensitive layer on an aluminum drum, and the surface is charged by the charging unit 4. Then, an electrostatic latent image in which charging is attenuated is formed on the surface that has received a laser beam from the exposure unit 5 described later. The photosensitive layer is not particularly limited, but for example, an amorphous silicon layer (a-Si) or an organic photosensitive layer (OPC) having excellent durability is preferable.

  The charging unit (charging charger) 4 charges the surface of the photosensitive drum 3 by discharging (for example, corona discharge). The charging unit 4 has, for example, a thin wire or the like, and discharges when a high voltage is applied using this as an electrode. The exposure unit (LSU) 5 irradiates the photosensitive drum 3 with a light beam (for example, a laser beam) based on the image data, and forms an electrostatic latent image on the surface of the photosensitive drum 3. The image data is transmitted from a personal computer (not shown).

  The developing device 6 attaches toner to the electrostatic latent image on the photosensitive drum 3 to form a toner image. Examples of the developer stored in the developing device 6 include a two-component developer composed of a toner component and a carrier and a one-component developer composed only of a toner component.

  The toner container 8 supplies toner to the developing device 6 and stores spare toner when the toner in the developing device 6 becomes insufficient. The transfer roller 9 shifts (transfers) the toner image formed on the surface of the photosensitive drum 3 onto the conveyed sheet without disturbing the toner image.

  The cleaning device 7 removes toner (residual toner) remaining on the surface of the photosensitive drum 3 after the toner image is transferred to the sheet, and is a rubbing roller that makes line contact with the longitudinal direction of the photosensitive drum 3. 21 and a cleaning blade 22 (see FIG. 7). The details of the cleaning device 7 will be described later. The paper feed mechanism 10 accommodates a sheet (paper, OHP, etc.) on which an image (toner image) is printed, and feeds the sheet to the transport unit 11 which is a sheet path from the paper feed mechanism 10 to the paper discharge unit 13. To be sent.

  The fixing device 12 converts the toner image transferred onto the sheet into a stable permanent image. For example, by applying energy such as heat and pressure using a heating roller and a pressure roller, the toner in a powder state A heat roller fixing method for fusing an image is used. The paper discharge unit 13 accommodates a sheet that has passed through the fixing device 12, that is, a sheet on which a permanent image is printed.

  Then, the exposure unit 5 emits a laser beam on the photosensitive drum 3 based on image data inputted in advance, thereby forming an electrostatic latent image based on the image data on the surface of the photosensitive drum 3. Thereafter, toner is attached to the electrostatic latent image by the developing device 6 (a toner image is formed), and the toner image is transferred onto the sheet by the transfer roller 9. Next, heat and pressure are applied to the sheet on which the toner image has been transferred by the fixing device 12 to form a permanent image.

  FIG. 2 is a side sectional view showing a configuration in the vicinity of the cleaning device of the present invention, and FIG. 3 is a partial sectional view as seen from the direction of arrow X in FIG. Portions common to FIG. 7 of the conventional example are denoted by the same reference numerals and description thereof is omitted. The cleaning device 7 removes residual toner on the surface of the photoconductive drum 3 and the housing 7a that forms an exterior having an opening toward the photoconductive drum 3, and slides the surface of the photoconductive drum 3 by rubbing and polishing. Excluding the rubbing roller 21, a cleaning blade 22 for removing residual toner on the surface of the photosensitive member, a conveying spiral 23 as a toner discharging means, and the conveying spiral 23 and the cleaning except for the toner moving space S (inside the broken line circle in the figure). The structure includes a partition wall 30 that seals between the blades 22, a scraper 31 for scraping off toner on the surface of the rubbing roller 21, and a urethane seal 33 for preventing waste toner in the housing 7a from leaking to the outside. .

  The rubbing roller 21 is in contact with the photosensitive drum 3, and is rotatably supported by front and rear side plates (not shown) of the housing 7a. The rubbing roller 21 is rotationally driven in the same direction on the contact surface with the photosensitive drum 3 by a driving means (not shown), but the peripheral speed is controlled to 1.2 times the peripheral speed of the photosensitive drum. . Examples of the rubbing roller 21 include a structure in which a foam layer made of EPDM rubber and having an Asuka C hardness of 55 ° is formed as a roller body around a metal shaft. The material of the roller body is not limited to EPDM rubber, but may be rubber of other materials or foamed rubber body, and those having an Asuka C hardness of 10 to 90 ° are preferably used.

  Further, a scraper 31 is pressed against the rotation direction in the counter direction on the surface of the rubbing roller 21 on the downstream side in the rotation direction from the contact surface with the photosensitive drum 3. The scraper 31 is, for example, an elastic plate made of SUS304 having a thickness of 0.05 mm, and its fixed end is attached to an attachment stay 35 attached to a front and rear side plate (not shown) of the housing 7a. The free end of the scraper 31 pressed against the rubbing roller 21 is located below the fixed end, and the toner scraped off from the rubbing roller 21 by the scraper 31 falls to the conveying spiral 23 side. Yes.

  Some toner also falls in the vicinity of the toner moving space S, but the waste toner scraped off from the surface of the photosensitive drum 3 rises one after another from the lower side of the toner moving space S. It moves to the conveyance spiral 23 side, and is further discharged from the cleaning device 7 by the conveyance spiral 23 while being supported on the partition wall 30 without falling.

  Here, the attachment direction of the scraper 31 is the tangential direction at the pressure contact on the surface of the rubbing roller 21, but the present invention is not limited to this, and the pressure contact may have a predetermined angle with respect to the tangent. Moreover, as the thickness of the scraper 31, a thickness of 0.02 to 2.0 mm can be suitably used in addition to the thickness of 0.05 mm, and the material is not limited to the weak magnetic SUS304, and the nonmagnetic SUS plate Various resin and metal blade plates, rubber blade plates and the like can be used.

The surface of the photosensitive drum 3 is fixed to the housing 7a via the mounting bracket 37 in a state where the cleaning blade 22 is in contact with the photosensitive drum 3 on the downstream side in the rotation direction from the contact surface with the rubbing roller 21. Has been. Here, a cleaning blade 22 made of polyurethane rubber having a JIS hardness of 78 ° and a thickness of 2 mm is used, the free end length of the cleaning blade is 10 mm, and the amount of biting into the photosensitive drum 3 at the contact portion is 1.5 mm. The contact point is attached at an angle of 22 degrees with respect to the tangential direction of the photosensitive member. The pressing force of the cleaning blade 22 on the photosensitive drum 3 side is set to 5 g / mm ² . The material, hardness, dimensions, the amount of biting into the photosensitive drum 3 and the pressure contact force of the cleaning blade 22 are appropriately set according to the specifications of the photosensitive drum 3.

  The residual toner removed from the surface of the photosensitive drum 3 by the cleaning blade 22 stays in the lower portion of the toner moving space S and rises, but further upwards through the toner moving space S with the help of the rotational conveying action of the surface of the rubbing roller 21. And is discharged to the outside of the cleaning device 7 as the conveyance spiral 23 rotates while being supported by the partition wall 30.

  Among the side plates of the housing 7a, the side plate positioned on the downstream side in the rotation direction of the photosensitive drum 3 (the right side in the drawing) is bent inwardly of the housing and extends so as to wrap around a part of the transport spiral 23, thereby forming the partition wall 30. Has been. By extending the end of the partition wall 30 substantially below the rotation shaft 23a of the transport spiral 23, the waste toner rising from the toner movement space S is quickly dropped without dropping again below the toner movement space S. 23 can be conveyed and discharged outside the apparatus.

  Further, a urethane seal 33 is attached to the side plate of the housing 7 a located on the upstream side (left side in the drawing) of the photosensitive drum 3 so as to have an acute angle with respect to the tangent at the contact point with the photosensitive drum 3. Yes.

  In the present embodiment, a sheet-like scraping member 40 is disposed between the housing 7 a of the cleaning device 7 and the conveying spiral 23. As shown in FIG. 2, the scraping member 40 is bent in an L shape in cross section. The short side of the L shape is fixed to the inner wall surface of the housing 7a, and the leading end of the long side becomes a free end to move the toner. It extends to near S.

  The scraping member 40 is lifted by the spiral wings 23b and elastically deformed with the rotation of the conveying spiral 23 (solid line in FIG. 2), and is in contact with the rotating shaft 23a by a restoring force (broken line in FIG. 2). Are repeatedly reciprocated to swing the free end between the tip of the cleaning blade 22 and the rubbing roller 21. The staying toner in the vicinity of the toner moving space S is loosened at the tip of the scraping member 40 and moves to the periphery of the conveying spiral 23 without solidifying, so that the waste toner in the housing 7a is efficiently conveyed to the outside.

  As a result, the toner removed from the photosensitive drum 3 cannot enter the housing 7a through the opening and leaks out of the urethane seal 33, contaminating the peripheral portion of the apparatus and the sheet on which the image is recorded, or solidified toner. As a result, it is possible to effectively prevent a problem that the tip of the cleaning blade 22 is deformed and the toner on the photosensitive drum 3 slips through and causes a cleaning failure.

  Further, the rubbing roller 21 has a function of polishing the surface of the drum by interposing a toner containing an abrasive between the photosensitive drum 3 and the function of cleaning the residual toner on the surface of the photosensitive drum 3. . For this reason, the toner tends to stay in the vicinity of the contact portion between the rubbing roller 21 and the photosensitive drum 3, but the scraping member 40 is used to prevent the toner around the rubbing roller 21 from being aggregated and solidified. By doing so, the toner used for polishing the drum surface can be efficiently replaced, and the polishing effect is also improved.

  As shown in FIG. 3, the scraping member 40 extends over the entire length of the conveying spiral 23. A number of scraping pieces 40a substantially parallel to the spiral feather 23b are formed on the free end side. Here, since the arrangement interval P1 of the scraping pieces 40a is set to 1.5 times the pitch P of the spiral feathers 23b, the spiral feathers 23b are caused by the progress of the phase of the spiral feathers 23b as the transport spiral 23 rotates. Alternately push up every other scraping piece 40a.

  As a result, the force for swinging the scraping member 40 is dispersed and the load on the transport spiral 23 is also reduced. Therefore, even if the transport spiral 23 is made of resin, the curving of the transport spiral 23 can be prevented. . Therefore, even when the pitch P of the conveying spiral 23 is widened to increase the toner conveying speed, the scraping member 40 can be swung without applying an excessive load to the conveying spiral 23, and the waste toner is quickly discharged. However, solidification of the toner can be effectively suppressed.

  The material of the scraping member 40 is not particularly limited as long as it is an elastic material that swings in contact with the spiral wings 23b of the conveying spiral 23. For example, a sheet made of polyethylene terephthalate (PET) (Lumirror sheet), a Teflon sheet, Various synthetic resin sheets such as Kapton that have a low frictional resistance can be used, but a Lumirror sheet is preferred from the standpoint of cost and durability. Further, the length, width, and thickness of the scraping member 40 are not particularly limited, and may be appropriately set depending on the outer diameter, the pitch P, and the like of the transport spiral 23.

  In FIG. 3, the arrangement interval P1 of the scraping pieces 40a is 1.5 times the pitch P of the spiral blades 23b, but the present invention is not limited to this. That is, by setting the arrangement interval P1 to be larger than the pitch P and not in a multiple of P, the timing at which the spiral blade 23b pushes up the scraping piece 40a may be shifted. However, if the arrangement interval P <b> 1 becomes too large, there is a possibility that the toner loosening effect in the axial direction of the transport spiral 23 may vary. Therefore, it is preferable to set the arrangement interval P1 to be less than twice the pitch P so that at least a part of the scraping piece 40a always overlaps each pitch of the spiral feathers 23b.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the base side (fixed end) of the scraping member 40 is connected and the free end side is divided into a plurality of scraping pieces 40a. However, as shown in FIG. The scraping pieces 40a may be arranged individually, or as shown in FIG. 4 (b), the tip of each scraping piece 40a is connected to form a window portion 41 facing the spiral blade 23b. The same effect can be obtained.

  In the above embodiment, only the configuration including the rubbing roller 21 and the cleaning blade 22 as the polishing system of the cleaning device 7 has been described. However, the configuration of the present invention includes, for example, only the rubbing roller 21 or the cleaning blade. Various configurations having the conveying spiral 23, such as a configuration having only the cleaning roller 22, a configuration having a cleaning roller having only a cleaning function instead of the rubbing roller 21, and a configuration having a fur brush instead of the cleaning blade 22. It can be applied to a cleaning device.

  Using the cleaning device of the present invention shown in FIGS. 2 and 3, the waste toner conveyance performance during continuous image printing was investigated. As the cleaning device, a resin conveyance spiral 23 having a spiral diameter of 12 mm and a pitch P of the spiral feathers 23b of 30 mm is used, and the arrangement interval P1 of the scraping pieces 40a having a thickness of 125 μm and a width of 14 mm is set to 35 mm. The fixed end of the scraping member 40 was stuck and fixed to the inner wall surface of the housing 7a with a double-sided tape.

  Further, as shown in FIGS. 5 and 6, the cleaning apparatus in which the scraping member 40 is fixed so that the arrangement interval P <b> 1 of the scraping pieces 40 a and the pitch P of the conveying spiral 23 are equal is the same as Comparative Examples 1 and 2. Investigated. In Comparative Example 1, the conveying spiral 23 having a pitch P1 of the spiral wings 23b of 15 mm was used, and scraping pieces 40a having a thickness of 125 μm and a width of 7 mm were arranged between the pitches so that the arrangement interval P1 was 15 mm.

  In Comparative Example 2, the conveying spiral 23 having the pitch P of the spiral feathers 23b of 30 mm was used, and the scraping pieces 40a having a thickness of 125 μm and a width of 14 mm were arranged between the pitches so that the arrangement interval P1 was 30 mm. In addition, the test was also performed in the case where the width of the scraping piece 40a was set to 7 mm, which was the same as in Comparative Example 1. The other configuration of the cleaning device and the fixing method of the scraping member 40 are the same as those of the present invention.

  As an evaluation method, the cleaning device of the present invention and Comparative Examples 1 and 2 are mounted on a test machine, and a test image having a printing rate of 10% is printed in a high-temperature and high-humidity environment (32.5 ° C., humidity) using a magnetic one-component pulverized toner. 80%) and 5,000 sheets each in a low temperature and low humidity environment (10 ° C, 15% humidity), leakage of toner from the urethane seal, cleaning effect on the drum surface, generation of abnormal noise due to curving of the conveying spiral, The toner loosening effect and the image quality were evaluated.

  As other test conditions, the outer diameter of the photosensitive drum was 30 mm, the rotation speed was 90 rpm, and the rubbing roller diameter was 14 mm. In addition, the spiral rotation speed was set to a normal speed (115 rpm) in the cleaning device of the present invention and Comparative Example 2, and the normal speed and the high speed (180 rpm) in the cleaning device of Comparative Example 1. The results are shown in Table 1.

※１；クリーニング不良による汚染発生
※２；ピッチムラ、ジッター発生

* 1; Contamination occurs due to poor cleaning * 2; Pitch unevenness and jitter occur

  As a result of the test, since the cleaning device of the present invention uses a conveying spiral with a wide pitch, toner leakage from the urethane seal portion and poor cleaning did not occur even when the conveying spiral was rotated at a normal speed. In addition, no abnormal noise was observed due to the curvature of the conveying spiral. This is because the arrangement interval P1 of the scraping pieces is wider than the pitch P of the spiral blades of the conveying spiral, and P1 is not a multiple of P, so the swing timing of each scraping piece is shifted and the load on the conveying spiral is reduced. It is thought that this is because

  On the other hand, in the cleaning device of Comparative Example 1, when the rotation speed was rotated at a normal speed because the pitch of the conveyance spiral was narrow, toner conveyance could not catch up and toner leakage or poor cleaning occurred. On the other hand, when rotating at high speed, vibration due to rotation of the conveying spiral was transmitted to the photosensitive drum, and image defects such as pitch unevenness and jitter occurred.

  On the other hand, in the cleaning apparatus of Comparative Example 2, when the width of the scraping piece was wide, toner leakage and poor cleaning did not occur as in the case of the present invention. However, since the rigidity of the scraping piece increased, the conveyance spiral A large load was applied, abnormal noise was generated due to the curvature of the conveying spiral, and finally it became difficult to rotate. Further, in Comparative Example 2, if the width of the scraping piece is narrowed, the conveyance spiral can be rotated, but there is a problem that the toner loosening effect is not uniform in the longitudinal direction of the spiral.

  The present invention relates to a housing disposed to have an opening on the image carrier side above the image carrier, a toner removing unit disposed in the opening to scrape residual toner on the surface of the image carrier, and the toner removing unit. A cleaning spiral having a spiral blade formed around the rotation shaft for transporting toner scraped off from the surface of the image carrier. A plurality of scraping pieces made of a swinging elastic material are arranged, and the arrangement interval of each scraping piece is wider than the pitch of the spiral wings and is not a multiple of the pitch.

  As a result, the force for swinging the scraping piece is dispersed and the load on the transport spiral is reduced, so that even when the pitch of the spiral blades is widened and the toner transport speed is increased, the transport spiral is prevented from being bent. In addition, it is possible to provide a cleaning device that can stably convey the toner. Further, since the arrangement interval of the scraping pieces is less than twice the pitch of the spiral wings, the toner loosening effect in the axial direction of the conveying spiral becomes more uniform.

  Further, the toner removing means is constituted by a cleaning blade and a cleaning roller, and the free end of the scraping piece is swung between the cleaning blade tip and the cleaning roller. Aggregation and solidification of staying toner can be effectively suppressed. Accordingly, the cleaning device can effectively prevent toner leakage from the seal portion and occurrence of cleaning failure due to deformation of the cleaning blade. Further, when the cleaning roller is used as a rubbing roller, the toner used for polishing can be efficiently replaced, and the polishing effect is improved.

  Also, by installing the cleaning device of the present invention, waste toner aggregation and solidification can be suppressed to improve toner discharge efficiency, and the occurrence of contamination inside the device and image defects due to toner leakage and poor cleaning can be effectively prevented. A preventable image forming apparatus can be realized easily and at low cost.

FIG. 2 is a schematic cross-sectional view showing a configuration of an image forming apparatus including the cleaning device of the present invention. These are side surface sectional drawings which show the structure of the cleaning device vicinity of this invention. These are the elements on larger scale which show the structure of the conveyance spiral periphery in the cleaning apparatus of this invention. These are top views which show the other structural example of a scraping off member. These are top views which show the relationship between the conveyance spiral of the comparative example 1, and a scraping member. These are top views which show the relationship between the conveyance spiral of the comparative example 2, and a scraping member. These are top sectional drawings which show the structure of the conventional cleaning apparatus.

Explanation of symbols

3 Photosensitive drum 7 Cleaning device 7a Housing 21 Rub roller (toner removing means)
22 Cleaning blade (toner removal means)
23 transport spiral 23a rotating shaft 23b spiral blade 30 partition wall 31 scraper 33 urethane seal 40 scraping member 40a scraping piece 100 image forming apparatus P (spiral blade) pitch P1 (scraping piece) arrangement interval

Claims (5)

A housing arranged to have an opening on the image carrier side above the image carrier, and a toner removing means arranged in the opening to scrape residual toner on the surface of the image carrier;
A cleaning spiral including a spiral disposed around the rotation shaft, the spiral blade for transporting the toner scraped off from the surface of the image carrier disposed above the toner removing unit;
A plurality of scraping pieces made of an elastic material that abuts and swings against the side surface of the conveying spiral are arranged, and the arrangement interval of the scraping pieces is wider than the pitch of the spiral wings and is a multiple of the pitch. A cleaning device characterized by not being.   The cleaning apparatus according to claim 1, wherein an interval between the scraping pieces is less than twice the pitch of the spiral wings.   The toner removing means includes a cleaning blade provided on the downstream side in the rotation direction of the image carrier in the opening, and a cleaning roller provided on the upstream side with respect to the cleaning blade. The cleaning apparatus according to claim 1, wherein the free end of the cleaning member swings between a tip of the cleaning blade and the cleaning roller.   The cleaning device according to claim 3, wherein the cleaning roller functions as a rubbing roller by contacting the image carrier with toner.   An image forming apparatus on which the cleaning device according to claim 1 is mounted.

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