Cleaning device, image forming unit and image forming apparatus

A cleaning device for an image forming apparatus includes a cleaning member that removes residual developer that remains on a image carrier, a rotary conveying member that conveys the removed residual developer toward a predetermined direction, and a housing that contains the rotary conveying member. The housing includes a support member that supports the cleaning member; and a protective member that has an inner wall which opposes outer periphery of the rotary conveying member and partially covers the rotary conveying member. The protective member is made of a resin molding material to which a filler is not added.

CROSS REFERENCE TO RELATED APPLICATION

The present application is related to, claims priority from and incorporates by reference Japanese Patent Application No. 2012-249117, filed on Nov. 13, 2012.

TECHNICAL FIELD

The present invention relates to a cleaning device that removes developer from an image carrier carrying a developer image formed by an image forming process of an electrophotographic method, an image forming unit that has the cleaning device, and an image forming apparatus that is provided with the image forming unit.

BACKGROUND

The image forming process of the electrophotographic method is widely used, for example, in an image forming apparatus such as a copier, a facsimile device and a printer. An image forming apparatus that operates using the electrophotographic method executes a series of processes such as a charging process uniformly charging a surface of an image carrier such as a photoreceptor, an exposure process irradiating the surface of the image carrier with light to form an electrostatic latent image, a developing process attaching the charged developer to the electrostatic latent image to form a developer image on the image carrier, a transfer process transferring the developer image to a recording medium such as a sheet, and a fusing process fusing the transferred developer image onto the recording medium.

However, in the transfer process, it is difficult for the entire developer image to be transferred from the image carrier to the recording medium so that it is possible for developer to remain on the image carrier. Therefore, in the image forming apparatus, a cleaning device is incorporated that removes, from the image carrier, the unwanted developer (or residual developer) remained after the transfer process. A cleaning device of this kind is disclosed, for example, in Japanese Patent Laid-Open Publication No. 2006-58729 (Patent Document 1).

For the above-described conventional cleaning device, there is a problem that noise is generated.

In view of the above-described problem, a purpose of the present invention is to provide a cleaning device, an image forming unit and an image forming apparatus that are able to suppress noise generation.

SUMMARY

A cleaning device incorporated in an image forming apparatus is disclosed. The image forming apparatus includes an image carrier and a transfer member, the image carrier carrying a developer image formed by an electrophotographic method, the transfer member transferring the developer image from the image carrier to a medium. The cleaning device includes a cleaning member that removes, from the image carrier, residual developer that remains on the image carrier without being transferred from the image carrier to the medium, a rotary conveying member that has a rotation axis in a predetermined direction, rotates about the rotation axis, and conveys the removed residual developer toward the predetermined direction, and a housing that contains the rotary conveying member. The housing includes a support member that supports the cleaning member, and a protective member that has an inner wall which opposes outer periphery of the rotary conveying member and partially covers the rotary conveying member. The protective member is made of a resin molding material to which a filler is not added. In the invention, the medium includes an intermediate transfer member as well as a recording medium.

According to the present invention, the housing that contains the rotary conveying member includes the support member that supports the cleaning member and the protective member that covers the rotary conveying member. The rigidity of the protective member is lower than the rigidity of the support member. Therefore, even when the rotating rotary conveying member rubs against the protective member, noise generation can be prevented. In addition, the support member has a rigidity higher than that of the protective member and thus can stably support the cleaning member.

DETAILED DESCRIPTION

In the following, various embodiments according to the present invention are described with reference to the drawings.

First Embodiment

FIG. 1schematically illustrates a configuration of an image forming apparatus1of a first embodiment according to the present invention. As illustrated inFIG. 1, the image forming apparatus1includes, in a casing10, image forming units20K,20Y,20M,20C respectively generating developer images of black (K), yellow (Y), magenta (M) and cyan (C); a tray11containing a recording medium Pa that is a transferred material; a roller12retrieving the recording medium Pa from the tray11; a hopping roller13sending out one sheet at a time the recording medium Pa retrieved from the tray11; conveying rollers15A,15B,16A,16B conveying toward the image forming unit20K the recording medium Pa sent out by the hopping roller13; a transfer belt49carrying thereon and conveying the recording medium Pa; transfer rollers40K,40Y,40M,40C transferring the developer images formed by the image forming units20K,20Y,20M,20C to the recording medium Pa; and a fuser unit60.

Further, the image forming apparatus1includes driving rollers47,48driving the transfer belt49. The transfer belt49is an endless elastic belt stretched between outer peripheries of the driving rollers47,48. An example of a constituent material of the transfer belt49is polyurethane rubber. The driving rollers47,48can cyclically move the transfer belt49by rotating counterclockwise.

The tray11has a function of containing a plurality of sheets of the recording medium Pa in a stacked state and is detachably attached to a frame of the image forming apparatus1. Examples of the recording medium Pa include sheet-like media such as sheets, plastic film, synthetic paper or fabric.

The image forming units20K,20Y,20M,20C are arranged in a row above the transfer belt49along a conveying direction of the recording medium Pa (−X-axis direction). Therefore, the recording medium Pa on the transfer belt49passes through immediately below the image forming units20K,20Y,20M,20C in this order. The transfer rollers40K,40Y,40M,40C are respectively arranged at positions opposing the image forming units20K,20Y,20M,20C across the transfer belt49.

The image forming unit20K that forms a black developer image has a developer cartridge21K, a photoreceptor drum24K, a charging roller25K, an LED head26K, a supply roller27K, a developing roller28K and a layer forming blade29K. The developer cartridge21K is detachably attached to a main body part of the image forming unit20K. The developer cartridge21K includes a developer containing part22K containing unused black developer, and a waste developer containing part23K containing residual developer that, as will be described later, is recovered without being transferred to the recording medium Pa. The developer containing part22K can supply developer from a supply port formed in a lower portion thereof to the supply roller27K.

As the developer, for example, pulverized toner manufactured using a pulverization method can be used. A manufacturing process of the pulverized toner includes, for example, a process of generating a melt-kneaded product by melt-kneading and cooling a toner raw material made of a binder resin, a coloring agent, a release agent, a charge control agent and the like; a process of generating toner base particles having an average particle size of a few μm by pulverizing and classifying the melt-kneaded product; and a process of generating a nonmagnetic one-component developer by adding an external additive such as hydrophobic silica to the toner base particles. As the binder resin, for example, a polyester resin having a glass transition temperature of about 40° C. can be used.

The photoreceptor drum24K as an image carrier has a tubular shape with a Y-axis direction inFIG. 1(direction perpendicular to a plane of the drawing) as a longitudinal direction, and is configured, for example, by a metal pipe (conductive substrate) of aluminum and the like and a photoconductive layer of an organic photoreceptor or the like formed around the metal pipe. During operation of the image forming apparatus1, the photoreceptor drum24K rotates clockwise at a predetermined speed about a rotation axis. The charging roller25K is in contact with a surface of the photoreceptor drum24K and uniformly charges the entire surface of the photoreceptor drum24K.

The LED head26K as an exposure part irradiates the surface of the rotating photoreceptor drum24K with pattern light corresponding to a print image and forms an electrostatic latent image. The LED head26K is configured with, for example, a large number of LED elements (light-emitting diode elements) arranged in the Y-axis direction along the surface of the photoreceptor drum24K, an LED drive circuit driving the LED elements, and a lens array guiding the emitting light of the LED elements to the surface of the photoreceptor drum24K.

The supply roller27K as a developer supply member has a tubular shape with the Y-axis direction as a longitudinal direction and rotates about its own central axis. The supply roller27K carries developer supplied from the developer containing part22K on its surface and supplies the developer to the developing roller28K. The developing roller28K has a tubular shape with the Y-axis direction as a longitudinal direction, and rotates counterclockwise about its own central axis and conveys the developer attached to its surface. The layer forming blade29K causes the developer on the developing roller28K to be formed into a thin layer. When a portion of the surface of the photoreceptor drum24K where an electrostatic latent image is formed reaches the developing roller28K, due to a potential difference between the electrostatic latent image and the developing roller28K, developer moves from the developing roller28K to the photoreceptor drum24K and forms a developer image on the photoreceptor drum24K. Thereafter, the transfer roller40K as a transfer member transfers the developer image on the photoreceptor drum24K to the recording medium Pa nipped (sandwiched) between the transfer roller40K and the photoreceptor drum24K. In this case, a transfer bias (voltage) is applied to the transfer roller40K. Therefore, under the action of the electrostatic force, the developer image can be transferred from the photoreceptor drum24K to the recording medium Pa.

The configuration of each of the other image forming units20Y,20M,20C other than the developer is the same as the configuration of the image forming unit20K that forms a black (K) developer image. The image forming unit20Y that forms a yellow (Y) developer image has a developer cartridge21Y, a photoreceptor drum (image carrier)24Y, a charging roller25Y, an LED head (exposure part)26Y, a supply roller27Y, a developing roller (developer carrier)28Y and a layer forming blade29Y. The developer cartridge21Y includes a developer containing part22Y containing unused yellow developer, and a waste developer containing part23Y containing residual developer that is recovered without being transferred to the recording medium Pa. The recording medium Pa supplied from the image forming unit20K on an upstream side is nipped (sandwiched) between the photoreceptor drum24Y and the transfer roller40Y of the image forming unit20Y. The transfer roller (transfer member)40Y transfers a yellow developer image on the photoreceptor drum24Y to the recording medium Pa.

The image forming unit20M that forms a magenta (M) developer image has a developer cartridge21M, a photoreceptor drum (image carrier)24M, a charging roller25M, an LED head (exposure part)26M, a supply roller27M, a developing roller (developer carrier)28M and a layer forming blade29M. The developer cartridge21M includes a developer containing part22M containing unused magenta developer, and a waste developer containing part23M containing residual developer that is recovered without being transferred to the recording medium Pa. The recording medium Pa supplied from the image forming unit20Y on an upstream side is nipped (sandwiched) between the photoreceptor drum24M and the transfer roller40M of the image forming unit20M. The transfer roller (transfer member)40M transfers a magenta developer image on the photoreceptor drum24M to the recording medium Pa.

The image forming unit20C that forms a cyan (C) developer image has a developer cartridge21C, a photoreceptor drum (image carrier)24C, a charging roller25C, an LED head (exposure part)26C, a supply roller27C, a developing roller (developer carrier)28C and a layer forming blade29C. The developer cartridge21C includes a developer containing part22C containing unused cyan developer, and a waste developer containing part23C containing residual developer that is recovered without being transferred to the recording medium Pa. The recording medium Pa supplied from the image forming unit20M on an upstream side is nipped (sandwiched) between the photoreceptor drum24C and the transfer roller40C of the image forming unit20C. The transfer roller (transfer member)40C transfers a cyan developer image on the photoreceptor drum24C to the recording medium Pa.

After a developer image of four colors is transferred to the recording medium Pa in the above image forming units20K,20Y,20M,20C, the recording medium Pa is conveyed to the fuser unit60. The fuser unit60has a function of fusing the developer image and fixing the developer image onto the recording medium Pa by applying pressure and heat to the developer image transferred to the recording medium Pa. As illustrated inFIG. 1, the fuser unit60has a fusing roller62of a circular pipe shape, and a pressing roller61having a surface layer made of an elastic material. A fuser unit heater (heat source)62H such as a halogen lamp is arranged inside the fusing roller62.

The recording medium Pa sent out from the fuser unit60is supplied to a pair of conveying rollers65A,65B. The conveying rollers65A,65B sandwich the recording medium Pa and supply the recording medium Pa to a pair of eject rollers66A,66B. The eject rollers66A,66B sandwich the recording medium Pa conveyed thereto and eject the recording medium Pa outside.

When print image data is input from an external device to the image forming apparatus1, in response to the input of the print image data, a controller (not illustrated in the drawings) starts a printing operation of the image forming apparatus1. Specifically, the controller causes the photoreceptor drums24K,24Y,24M,24C of the above image forming units20K,20Y,20M,20C, the charging rollers25K,25Y,25M,25C, the transfer belt49and the developing rollers28K,28Y,28M,28C to respectively rotate. At the same time, the controller separately applies a bias voltage from a power circuit (not illustrated in the drawings) to each of the charging rollers25K,25Y,25M,25C, the developing rollers28K,28Y,28M,28C, the supply rollers27K,27Y,27M,27C, the layer forming blades29K,29Y,29M,29C and the transfer rollers40K,40Y,40M,40C. Further, the controller causes the pressing roller61and the fusing roller62inside the fuser unit60to rotate, and supplies power to the fuser unit heater62H to adjust temperature of the fusing roller62.

Thereafter, in accordance with the timing at which the recording medium Pa reaches the image forming units20K,20Y,20M,20C, the controller drives the LED heads26K,26Y,26M,26C and respectively irradiates the photoreceptor drums24K,24Y,24M,24C with pattern light corresponding to a print image from the LED heads26K,26Y,26M,26C. As a result, electrostatic latent images are respectively sequentially formed on the surfaces of the photoreceptor drums24K,24Y,24M,24C. As described above, charged K, Y, M and C developers are respectively attached to the electrostatic latent images on the photoreceptor drums24K,24Y,24M,24C by electrostatic forces to form developer images. The developer images of the four colors are transferred to the recording medium Pa and are superimposed. Thereby, a color developer image is formed on the recording medium Pa.

The fuser unit60fixes the color developer image on the recording medium Pa conveyed thereto onto the recording medium Pa. Thereafter, the recording medium Pa is ejected outside the image forming apparatus1by the conveying rollers65A,65B and the eject rollers66A,66B.

Developer attached to a surface of the transfer belt49without being transferred to the recording medium Pa is recovered by a belt cleaning device50illustrated inFIG. 1. The belt cleaning device50includes a cleaning blade51scraping off the developer from the surface of the transfer belt49and a waste developer recovery container52containing the developer scraped off. The cleaning blade51has an edge portion made of an elastic material. By bringing the edge portion into contact with the transfer belt49, the developer can be scraped off from the transfer belt49.

In the image forming units20K,20Y,20M,20C, after the developer images are respectively transferred to the recording medium Pa, there may be developers remaining on surfaces of the photoreceptor drums24K,24Y,24M,24C. Such residual developers respectively reach cleaning parts30K,30Y,30M,30C along with the rotations of the photoreceptor drums24K,24Y,24M,24C and are removed.

Next, configurations and operations of the cleaning parts (cleaning devices)30K,30Y,30M,30C of the present embodiment are described.

FIG. 2illustrates a cross-sectional view of a schematic configuration of the cleaning part30K in the image forming unit20K of the present embodiment. As illustrated inFIG. 2, the cleaning part30K has a cleaning member (blade unit)31removing the residual developer on the photoreceptor drum24K from the photoreceptor drum24, a spiral-shaped rotary conveying member37conveying the removed residual developer to a vicinity of one end of the photoreceptor drum24K in the longitudinal direction, and a housing34containing the rotary conveying member37. The housing34is configured with a support member35and a protective member36that are fixed to each other. InFIG. 2, direction B (negative X direction) in which the recording medium Pa is carried is defined as a medium carrying direction.

FIG. 3illustrates a perspective view of an example of the rotary conveying member37of the present embodiment and peripheral members thereof. As illustrated inFIG. 3, the rotary conveying member37is made of a wire that spirally extends in the Y-axis direction along the surface of the photoreceptor drum24K. When the rotary conveying member37rotates about its own rotation axis, an inclined curved surface of the spiral-shaped wire functions as an action surface pushing the developer toward the −Y-axis direction. Therefore, while rotating about the rotation axis inside the housing34, the rotary conveying member37can convey the removed residual developer to the vicinity of the one end of the photoreceptor drum24K in the longitudinal direction.

As illustrated inFIG. 3, a base end portion of the rotary conveying member37is fixed on a transmission gear57. An end portion of the photoreceptor drum24K is fixed to a drive gear55. The drive gear55rotates in response to a drive force transmitted from a power source (not illustrated in the drawings) such as a motor and thereby causing the photoreceptor drum24K to rotate. An outer peripheral surface of an idle gear56is engaged with both the drive gear55and the transmission gear57. Therefore, the transmission gear57rotates in response to a rotational drive force transmitted from the drive gear55via the idle gear56. Therefore, the rotary conveying member37can rotate in the same circumferential direction as the photoreceptor drum24K at a speed that is synchronized with a rotating speed of the photoreceptor drum24K.

The rotary conveying member37can be prepared, for example, by spirally winding a metal wire around a core and then removing the core. As the wire, a hard steel wire (such as stainless steel) may be used. Further, with regard to dimensions of the rotary conveying member37, for example, an outer diameter (spiral diameter) of the rotary conveying member37may be within a range of 5.4 mm-5.8 mm, and an outer diameter of the wire may be about 0.8 mm.

As illustrated inFIG. 2, the cleaning member31is configured with a cleaning blade32that scrapes off the residual developer from the photoreceptor drum24K while being in slidable contact with the surface of the rotating photoreceptor drum24K, and a metal blade support plate33that is fixed to the housing34. The blade support plate33forms a base end portion of the cleaning member31. The cleaning blade32is attached to the blade support plate33using an adhesive. The cleaning blade32is, for example, an elastic body made of a resin material such as urethane rubber. A front end portion (edge portion)32aof the cleaning blade32needs to be in contact with the surface of the photoreceptor drum24K at a certain angle and at a certain pressure. Further, in order to suppress wear of the surface of the photoreceptor drum24K and efficiently remove the residual developer, it is desirable that variation in contact pressure between the cleaning blade32and the photoreceptor drum24K be suppressed. In view of the above, it is required that the housing34supporting the cleaning member31have a high rigidity.

When the developer scraped off from the surface of the photoreceptor drum24K moves inside the housing34to the rotary conveying member37, as illustrated inFIG. 3, the rotary conveying member37rotates to convey the developer to a developer conveying belt41K. The developer conveying belt41K is a caterpillar-like elastic belt and is stretched around a roller43arranged at an upper position. A rotation drive gear44can cyclically move the developer conveying belt41K in a direction as indicated by an arrow by applying a rotational drive force to the developer conveying belt41K via an action gear45. As a result, the developer conveying belt41K can carry on its surface the developer conveyed thereto by the rotary conveying member37and convey the developer upward. The developer conveyed upward falls down to a surface of a developer recovery member42K and is sent by the developer recovery member42K into the waste developer containing part23K (FIG. 1).

The developer recovery member42K has a tubular shape and projects into interior of the waste developer containing part23K (FIG. 1) from a through hole formed on a side frame (not illustrated in the drawings) of the image forming unit20K. A spiral-shaped concave-convex portion is formed on the surface of the developer recovery member42K. The spiral-shaped concave-convex portion can rotate about a rotation axis of the developer recovery member42K and send the developer into the interior of the waste developer containing part23K.

A projection part35pis disposed on an upper surface of the support member35and at a most downstream side in the medium carrying direction B. The upper surface may be described as a farther surface from a path of the recording medium. The projection part35pprojects toward positive Z direction inFIG. 2. The projection height H2is almost the same as the thickness of the blade support plate33. Alternatively, the height H2may be smaller than the thickness of the blade support plate33. The projection part35pfunctions to prevent the toner from leaking outside through an adhesive area335between the blade support plate33and the support member35. The seal member39is disposed to primarily prevent the toner from entering the adhesive area335. However, in a case where a crack occurs in the adhesive area335, the toner is likely to enter the crack and might come out. The projection part35pis disposed to stop such toner accidentally coming out through the adhesive area335.

There is a space between the projection part35pand the blade support plate33. Specifically, the space with a width W2is defined from the most downstream edge33dof the blade support plate33to the most upstream edge of the projection part35p. In the embodiment, the support member35is made of resin. When the support member35is heated or cooled, warps of the support member35in X or Z direction can be created along Y direction. If there is no space between the projection part35pand the blade support plate33and the warp occurs, they may contact and the arraignment (angle, position, pressure to provide) of the cleaning blade32may become out of order.

As illustrated inFIG. 2, the housing34is configured with the support member35of high rigidity properly supporting the blade support plate33, and the protective member36of low rigidity having an inner wall36sthat opposes outer periphery of the rotary conveying member37and partially covers the rotary conveying member37. An inner wall35sof the support member35does not oppose the rotary conveying member37.

Further, in order to prevent the residual developer removed by the cleaning blade32from falling onto the transfer belt49through a gap between a lower end portion of the protective member36and the surface of the photoreceptor drum24K, a film member38is fixed to the lower end portion of the protective member36using a double-sided adhesive tape. As a result, the transfer belt49and the recording medium Pa can be prevented from being contaminated, and efficiency of conveying the developer can also be improved.

Further, in order to prevent the removed residual developer from leaking out the housing34, an elastic seal member39filling a gap between the inner wall35sof the support member35and the blade support plate33is attached using a double-sided adhesive tape. An attachment position of the seal member39is above a seam365between the support member35and the protective member36and is sufficiently distanced from the rotary conveying member37. Therefore, even when the rotary conveying member37vibrates and is upwardly displaced, the rotary conveying member37can be reliably prevented from coming into contact with the seal member39.

In the embodiment, the support member35is made of resin. The blade support plate33is made of metal. Since thermal expansion rates of these materials are not the same (resin's expansion rate is generally grater than that of metal), warps of the support member35in X or Z direction can be created along Y direction with respect the blade support plate33when the temperature changes. Due to the warp of the support member35, it is practically difficult to completely attach an entire surface of the support member35to an entire surface of the blade support plate33in Y direction. If the seal member39is not present, toner is likely to come out of the unit through a gap created by the warp when the unit lies. Specifically, when the surface of the unit in the negative X direction faces down, the toner will frequently come out through the gap.

Further, as illustrated inFIG. 2, the rotary conveying member37is arranged at a position close to the inner wall36sof the protective member36. When the gap (W1) between the rotary conveying member37and the inner wall36sis too wide, the developer may stay or accumulate in the gap so that the efficiency of conveying the developer deteriorates. From a point of view of preventing this, it is desirable that the gap (W1) between the rotary conveying member37and the inner wall36sbe 0.5 mm or less.

On the other hand, since the gap (W1) between the rotary conveying member37and the protective member36is narrow, outer periphery of the rotating rotary conveying member37may come into contact with the inner wall36sof the protective member36. Conventionally, as disclosed in Patent Document 1, there is a problem that, due to contact with each other between the rotary conveying member and the inner wall of the housing, friction is generated and high frequency noise is generated. The conventional housing is a resin molded product integrally molded using a resin molding material and is required to have high rigidity in order to properly support a cleaning blade fixed to the housing. However, due to the high rigidity of the housing, there is a problem that, when the housing and the rotary conveying member come into contact with each other to generate friction, high frequency noise is generated.

In contrast, the housing34of the present embodiment is configured with two members, that is, the support member35of high rigidity properly supporting the cleaning member31and the protective member36of low rigidity covering the rotary conveying member37. The protective member36has a lower rigidity and a lower dynamic friction coefficient than the support member35. Therefore, even when the rotary conveying member37rubs against the protective member36, generation of high frequency noise can be prevented. In addition, the support member35has a rigidity higher than that of the protective member36and thus can properly support the cleaning member31.

The support member35can be prepared using a resin molding material to which a filler for rigidity reinforcement is added. As the resin molding material of the support member35, for example, a thermosetting resin such as a modified polyphenylene ether (m-PPE) resin may be used. As the filler, for example, an inorganic filler of which glass fiber is a main component may be added. The filler's amount in the support member35is preferably within 10 to 50%. When the support member35is prepared using the m-PPE resin and glass fiber of an additive rate of 20%, as the rigidity of the support member35, a bending strength of about 107 MPa based on a measurement method in accordance with “ASTM D790” can be realized.

On the other hand, it is desirable that the protective member36be prepared using a resin molding material to which a filler is not added. As the resin molding material of the protective member36, for example, a thermoplastic resin such as an ABS resin may be used. When the protective member36is prepared using the ABS resin, as the rigidity of the protective member36, a bending strength of about 75 MPa based on a measurement method in accordance with “ASTM D790” can be realized. The filler reinforces rigidity of a resin molded product. On the other hand, the filler is exposed from a surface of the resin molded product. Therefore, the surface has a rough concave-convex surface. Therefore, when the rotary conveying member37made of metal rubs against the surface of the resin molded product of this kind, high frequency noise unpleasant to hear is generated. The protective member36of the present embodiment does not contain the filler and has low rigidity. Therefore, the generation of this kind high frequency noise can be avoided.

It is preferred that the rigidity of the support member35is more than 100 MPa, and the rigidity of the protective member36is less than 80 MPa based on the measurement method in accordance with ASTM D790. Also, it is noted that the gap between rigidities of the support member35and protective member36is preferably 20 MPa or more. The ASTM is a worldwide standard which is formerly known as the American Society for Testing and Materials.

FIG. 4illustrates a perspective view of a specific example of the housing34containing the rotary conveying member37.FIG. 5Aillustrates a perspective view of the support member35ofFIG. 4in which the cleaning member31is not installed; andFIG. 5Billustrates a perspective view of the support member35in which the cleaning member31is installed. Further,FIG. 6illustrates a perspective view of the protective member36ofFIG. 4alone.

As illustrated inFIG. 5A, the support member35is a resin molded product having a main body part35c, and side plate parts35a,35bthat respectively project from both end portions of the main body part35cin a longitudinal direction. Through holes35ah,35bhare respectively formed on the side plate parts35a,35ballowing two end portions of the photoreceptor drum24K in the longitudinal direction to be respectively inserted thereto. The main body part35chas insertion holes35e,35dthat respectively allow two end portions of the rotary conveying member37in the longitudinal direction to be inserted thereto, and mounting parts35h,35jfor mounting the cleaning member31. Attaching holes35i,35kare respectively formed on the mounting parts35h,35j.

As illustrated inFIG. 5B, the cleaning member31is installed on the support member35using fastening members74,75that are screw members. In the state in which the cleaning member31is installed, two end portions of the cleaning member31are mounted on the mounting parts35h,35jof the support member35. Shaft portions of the fastening members74,75are respectively inserted through the two end portions of the cleaning member31and screwed to attaching holes35i,35kof the support member. Heads of the fastening members74,75respectively cause the cleaning member31to abut on the mounting parts35h,35jof the support member35. In this way, the cleaning member31can be fixed on the support member35using the fastening members74,75.

On the other hand, as illustrated inFIG. 6, the protective member36is a resin molded product having the inner wall36sfor covering the outer periphery of the rotary conveying member37, and insertion holes36j,36kfor allowing the two ends of the rotary conveying member37to be respectively inserted thereto. Attaching holes36h,36iare formed on the protective member36.

The protective member36ofFIG. 6and the support member35ofFIG. 5Bare bonded together by using fastening members72,73(FIG. 4) that are screw members. Specifically, the support member35and the protective member36are superimposed in such a way that the insertion holes36j,36kof the protective member36ofFIG. 6and the insertion holes35e,35dof the support member35ofFIG. 5Bare coaxially arranged. Next, shaft portions of the fastening members72,73are screwed to the attaching holes36h,36iof the protective member36via insertion holes (not illustrated in the drawings) of the support member35, and thereby the housing34ofFIG. 4can be configured. Further, the rotary conveying member37is inserted into the insertion holes36j,36k,35e,35dof the protective member36and the support member35and is supported.

In the above, the cleaning part30K of the image forming unit20K is described. Configurations of cleaning parts30Y,30M,30C of the other image forming units20Y,20M,20C are the same as the configuration of the cleaning part30K of the image forming unit20K and thus their detailed description is omitted.

Further, also in the image forming units20Y,20M,20C, developer conveying belts41Y,41M,41C convey upward used developer recovered by the cleaning parts30Y,30M,30C. Further, developer recovery members42Y,42M,42C can respectively send the used developer conveyed upward by the developer conveying belts41Y,41M,41C into interiors of waste developer containing parts23Y,23M,23C. Configurations of the developer conveying belts41Y,41M,41C and their drive mechanism are the same as the configuration of the above-described developer conveying belt41K and its drive mechanism. Configurations of the developer recovery members42Y,42M,42C are also the same as the configuration of the above-described developer recovery member42K.

As described above, in the cleaning parts30K,30Y,30M,30C of the present embodiment, as illustrated inFIG. 2, the housing34that houses the rotary conveying member37is configured with two members, the support member35of high rigidity and the protective member36of low rigidity. The support member35does not come in contact with the rotary conveying member37. The protective member36that may come in contact with the rotary conveying member37has a rigidity lower than that of the support member35. Therefore, even when the rotary conveying member37rubs against the protective member36, generation of high frequency noise can be prevented. In addition, the support member35has a rigidity higher than that of the protective member36and thus can properly support the cleaning member31. Therefore, it is possible to suppress generation of high frequency noise unpleasant to hear and to realize high cleaning performance.

Further, since the housing34of the present embodiment has the above-described configuration, there is an advantage that the housing34has high durability.

In the above embodiment, the toner images formed on the photoreceptor drums (24K to24C) are directly transferred to the recording medium Pa that is conveyed on the transfer belt49. However, the invention may use an intermediate transfer member (belt or drum). In such an embodiment, a toner image formed on a photoreceptor drum is primarily transferred to the surface of the intermediate transfer member. Secondarily, the transferred toner image on the intermediate transfer member is transferred to a recording medium on a transfer belt. Regarding features and structure of the intermediate transfer member, the application is incorporated with U.S. Pat. No. 8,509,648.

Second Embodiment

Next, a second embodiment according to the present invention is described. A configuration of an image forming apparatus of the second embodiment is the same as the configuration of the image forming apparatus1(FIG. 1) of the first embodiment except a part of a configuration of a housing of a cleaning part that removes residual developer from the photoreceptor drum24K,24Y,24M,24C.

FIG. 7illustrates of cross-sectional view of a schematic configuration of a cleaning part30KB of the second embodiment. The cleaning part30KB can remove residual developer from the photoreceptor drum24K. Configurations of cleaning parts removing residual developer from the photoreceptor drums24Y,24M,24C are also the same as the configuration of the cleaning part30KB ofFIG. 7.

The cleaning part30KB has the cleaning member31removing residual developer on the photoreceptor drum24K from the photoreceptor drum24K, the rotary conveying member37conveying the removed residual developer to the vicinity of one end of the photoreceptor drum24K in the longitudinal direction, and the housing34B housing the rotary conveying member37. The housing34B is configured with a support member35B of high rigidity properly supporting the blade support plate33and the protective member36of low rigidity. The configuration of the protective member36ofFIG. 7is the same as the configuration of the protective member36(FIG. 2) of the above-described first embodiment. Similar to the support member35of the first embodiment, the support member35B is prepared using a resin molding material to which a filler for rigidity reinforcement is added.

The support member35B of the present embodiment has an inner wall35Bs opposing the outer periphery of the rotary conveying member37. The inner wall35Bs covers the outer periphery of the rotary conveying member37. It is in this point that the support member35B is structurally different from the support member35of the first embodiment.

A gap D between the inner wall35Bs of the support member35B and the outer periphery of the rotary conveying member37is larger than a gap d between the inner wall36sof the protective member36and the outer periphery of the rotary conveying member37. Further, it is desirable the gap D be adjusted to a gap (for example, about 1 mm) that does not allow the inner wall35Bs and the rotary conveying member37to easily come into contact with each other. Further, as illustrated inFIG. 7, a diameter A of an opening of the housing34B is smaller than an outer diameter (diameter dimension) of the rotary conveying member37. Therefore, the housing34B has a structure that is easy to take in developer scraped off from the photoreceptor drum24K. Therefore, the efficiency of conveying the developer by the rotary conveying member37can be improved.

Further, a front end portion of the support member35B is interposed between the cleaning blade32and the rotary conveying member37. Therefore, even when the rotary conveying member37vibrates and is displaced toward a cleaning blade32side, the rotary conveying member37and the cleaning blade32can be reliably prevented from coming into contact with each other.

Further, in the above-described first embodiment, in order to prevent the removed residual developer from leaking out the housing34, as illustrated inFIG. 2, the seal member39is attached between the inner wall35sof the support member35and the cleaning member31. In contrast, the front end portion of the support member35B of the present embodiment extends to a vicinity of the cleaning blade32. Therefore, there is an advantage that it is not necessary to provide the seal member39.

In the above, various embodiments according to the present invention are described with reference to the drawings. However, these embodiments are examples of the present invention, and various embodiments other than the above can also be adopted. For example, as illustrated inFIG. 4, the support member35and the protective member36of the above first embodiment are bonded using the fastening members72,73. However, the present invention is not limited to this. The support member35and the protective member36may also be bonded to each other using an adhesive. The same applies to the bonding between the support member35B and the protective member36of the second embodiment.

The present invention can be applied to a printer. However, the present invention is not limited to a printer, but can also be applied to a copier, a facsimile device or a multifunctional peripheral (MFP). The MFP is an image forming apparatus that is combinedly equipped with functions of a plurality of devices including such devices as a copier, a printer, an image scanner and a facsimile device.