JP2009008962A - Cleaning device and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device for forming on a rubbing roller, a toner layer more uniformly than before with a predetermined thickness and preventing defects in image formation such as a streak image, toner drop, image flow and a leak blackspot by suppressing the influence of the charge-up of the toner layer on a photoreceptor drum. <P>SOLUTION: A conveyance spiral 23, a rubbing roller 21 collecting toner and polishing the photoreceptor drum 3 and a scraper 31 are provided in a housing 7a. A coil spring 32 is disposed between the scraper 31 and the photoreceptor drum 3. When the photoreceptor drum 3 is rotated, the toner layer on the rubbing roller 21 is disturbed by the coil spring 32 to form a uniform layer thickness by the scraper 31. <P>COPYRIGHT: (C)2009,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 powdered developer (hereinafter referred to as toner) is mainly used. Then, an electrostatic latent image formed by charging and exposure on an image carrier such as a photosensitive drum is visualized by toner in the developing device, and the toner image is transferred onto a recording medium, followed by fixing processing. An image forming process to be performed is generally performed. In such an image forming apparatus, a cleaning device for removing residual toner on the surface of the photosensitive drum is mounted.

  When a photosensitive drum formed by laminating a surface layer made of α-Si around a cored bar is used, α-Si on the drum surface is oxidized by discharge such as corona discharge during charging. It has been known. Since α-Si becomes highly hydrophilic when oxidized, moisture in the air is easily adsorbed on the drum surface. And when the ion which generate | occur | produced by discharge melt | dissolves in the adsorbed water | moisture content, the electrical resistance of a drum surface will fall. As a result, an electrostatic latent image is not sufficiently formed, and a so-called image flow phenomenon may occur in which a clear image is not formed.

  In order to prevent such image flow, a technique for polishing the surface of a photosensitive drum by using toner as an abrasive and disposing a rubbing roller in a cleaning device is known. In such a technique, when the photosensitive drum rotates by bringing the rubbing roller into contact with the photosensitive drum, the rubbing roller collects and collects toner on the surface of the photosensitive drum, and collects a part of the collected toner. The fine oxide film formed on the drum surface can be scraped off while being supplied onto the surface. Then, the image surface is prevented by polishing the surface of the drum using the rubbing roller in this way.

  At this time, if a large amount of the collected toner adheres to the rubbing roller, the cleaning device may be filled with toner, and the toner may be ejected from a seal portion provided between the cleaning device and the photosensitive drum. For this reason, conventionally, the amount of toner on the surface of the rubbing roller has been regulated by disposing a stainless scraper on the surface of the rubbing roller.

On the other hand, a technique for further suppressing image flow has been proposed. For example, Patent Document 1 includes a toner containing an abrasive and an elastic body that captures the abrasive on the surface of the rubbing roller 21. A cleaning device is disclosed.
Japanese Patent Laid-Open No. 10-63157

  By the way, the technique of Patent Document 1 captures an abrasive material by an elastic body provided on the surface of the rubbing roller 21 and increases the ratio of the abrasive material to the toner, so that polishing is effective even with a relatively small amount of toner. It is intended to make it possible to perform.

  However, for example, when a stainless steel scraper made of SUS304 is provided on the rubbing roller, a portion where the toner layer is partially insufficient in the axial direction may occur or the toner layer may become thin, and polishing is not possible. May be sufficient. Since SUS304 has a relatively small contact angle with water, the toner tends to easily adhere to it, and the toner layer becomes insufficient at the portion where the toner has adhered. In addition, since SUS304 has a relatively large longitudinal elastic modulus, it cannot be sufficiently in close contact with the rubbing roller, and the contact pressure against the rubbing roller becomes high, resulting in unevenness in the toner layer, It tends to be thinner.

  As described above, when the toner layer adheres to the scraper, the photosensitive drum is not polished at the attached portion, so that a portion that is not polished in a streaky shape is generated, and this appears as a streak in the image. May occur. Further, when unevenness occurs in the toner layer or the toner layer becomes thin, the polishing force is reduced in a portion where the toner is insufficient, and a partial image flow may occur.

  On the other hand, for example, when an elastic material having a relatively large contact angle with water, such as polyethylene terephthalate (PET), is used as the scraper, adhesion of toner to the scraper is improved and adhesion to the rubbing roller is also improved. It tends to improve. However, although it can be in close contact with the rubbing roller, the contact pressure on the rubbing roller is lowered, and as a result, the toner layer becomes too thick and toner may be ejected from the housing. In addition, since the toner cannot be sufficiently pressed against the rubbing roller, the toner layer is not uniformly formed, and partial polishing may be insufficient. Furthermore, if the toner layer becomes too thick, the pressure at the contact portion between the rubbing roller and the photosensitive drum is dispersed, so that the polishing force is reduced and image flow may occur.

  Therefore, for example, the scraper has a two-layer structure composed of PET and SUS304, and by bringing the PET layer into contact with the toner, adhesion of the toner is suppressed, adhesion to the rubbing roller is improved, and the toner is slid. Since it can be sufficiently pressed against the rubbing roller, the toner layer can be uniformly formed in a predetermined layer thickness suitable for polishing.

  However, even when the toner layer is formed as described above, black spots may occur in the formed image. Such a black spot is a so-called leak black spot, and the toner layer on the rubbing roller is charged up, and a discharge occurs between the toner and the photosensitive drum. As a result, a leak hole is formed in the charged layer on the surface of the photosensitive drum. A cracked part occurs. And it is guessed that this perforated part appears as a leak black spot in the formed image.

  In addition, the toner layer is charged up by rotating together with the rubbing roller without changing the outermost surface of the uniformly formed toner layer, so that only the outermost surface causes friction with the scraper or the photosensitive drum for a long time. It is thought that it was caused by receiving it.

  In view of the above problems, the present invention can form a toner layer capable of further suppressing the charge-up of the toner layer on the surface of the rubbing roller more uniformly with a predetermined layer thickness. An object of the present invention is to provide a cleaning device capable of suppressing problems in image formation such as streak images, toner dropping, image flow, and leaked black spots, and an image forming apparatus equipped with the same.

  A housing arranged to have an opening on the image carrier side; and a housing arranged in the opening, rotatably contacting the image carrier and collecting a part of residual toner on the surface of the image carrier. A cleaning member that supplies a part of the collected toner to the surface of the image carrier and polishes the surface, and is disposed downstream of the cleaning member in the rotation direction of the surface of the image carrier, and is collected by the cleaning member. A cleaning device comprising: a toner removing unit that scrapes off the residual toner that has not been removed; and a toner conveying unit that conveys the toner collected and scraped off from the surface of the image carrier by the cleaning member and the toner removing unit. In this case, at least the contact portion with the toner is made of an elastic material having a contact angle with water of 70 ° or more, and the toner layer adhering to the surface of the cleaning member is regulated to a predetermined layer thickness. A toner regulating means capable of cleaning the toner, and disposed on the upstream side of the cleaning member in the rotational direction of the cleaning member and on the downstream side of the rotational direction of the image carrier, and scrapes the toner layer adhering to the cleaning member. And a toner disturbing means for disturbing.

  According to the present invention, the toner disturbing means is a coil spring.

  In the invention, it is preferable that the toner regulating means regulates the thickness of the toner layer attached to the surface of the cleaning member to 50 μm or more and 100 μm or less.

  In the invention, it is preferable that the toner regulating unit includes a sheet-like member having a two-layer structure including a first layer on a part in contact with the toner and a second layer on the part on the side opposite to the contact surface. It is formed, and the second layer is made of a material having a larger longitudinal elastic modulus than the first layer.

  Further, the present invention is an image forming apparatus on which any one of the above-described cleaning devices is mounted.

  According to the first configuration of the present invention, the toner layer adhered to the surface of the cleaning member is scraped off by providing the toner scraping means, and the toner located on the outermost surface of the toner layer is separated from the innermost layer from the outermost surface. It can be mixed and mixed with the toner that has been positioned in the toner and the toner collected from the image carrier. For this reason, it is possible to replace the toner located on the outermost surface of the toner layer, which is susceptible to friction, and to suppress the charge up of the toner layer. As a result, the occurrence of leak black spots can be suppressed.

  Further, the toner contact means made of an elastic material having a contact angle with water of 70 ° or more at the contact portion with the toner increases the so-called water repellent effect on the surface of the contact portion with the toner. It becomes difficult to become familiar with the surface. Thereby, adhesion of toner can be suppressed. Further, by using such an elastic material, the toner can be brought into close contact with each other, and a uniform toner layer without unevenness can be obtained.

  Further, by bringing the contact portion into contact with the toner and setting the toner layer to a predetermined layer thickness, the toner layer can have a layer thickness suitable for polishing. Therefore, the polishing force of the cleaning member can be made uniform, and the lack of polishing force due to the toner layer being too thin, the drop of toner due to the toner layer being too thick, and the lack of polishing force can be suppressed.

  Therefore, a toner layer capable of further suppressing the charge-up of the toner layer can be uniformly formed with a predetermined layer thickness, and images such as streak images, toner dropping, image flow, and leaked black spots can be further formed. Problems in formation can be suppressed.

  Further, according to the second configuration of the present invention, in the cleaning device of the first configuration, the toner turbulence means is a coil spring, thereby suppressing charge-up of the toner layer with a simpler configuration. be able to. Therefore, with a simpler configuration, it is possible to further suppress problems in image formation such as streak images, toner drop, image flow, and leaked black spots.

  According to the third configuration of the present invention, in the cleaning device having the first or second configuration, the toner regulating means regulates the layer thickness of the toner layer attached to the cleaning member to 50 μm or more. Insufficient polishing force due to toner shortage can be further suppressed, and the occurrence of image flow can be further suppressed. On the other hand, when the toner regulating means regulates the thickness of the toner layer to 100 μm or less, it is possible to further suppress toner drop and insufficient polishing power due to the toner layer being too thick. Therefore, problems in image formation such as toner drop and image flow can be further suppressed.

  According to the fourth configuration of the present invention, in the cleaning device having any one of the first to third configurations, the toner restricting means includes the first layer on the contact surface side portion of the toner and the contact with the first layer. A sheet member having a two-layer structure composed of a second layer on the side opposite to the surface is formed, and the second layer is made of a material having a longitudinal elastic modulus larger than that of the first layer. That is, the first layer is a low elastic layer having a relatively low longitudinal elastic modulus, and the second layer is a high elastic layer having a relatively large longitudinal elastic modulus, thereby suppressing adhesion to the toner by the first layer. And the second layer sufficiently presses the first layer against the cleaning member, so that the first layer sufficiently absorbs the toner against the cleaning member. Can be pressed.

  As a result, the toner layer can be uniformly formed on the surface of the cleaning member with a layer thickness suitable for polishing. Therefore, a uniform toner layer can be formed more effectively without complicating the structure of the members, and problems in image formation such as streak images, toner dropping, and image flow can be suppressed.

  Further, according to the fifth configuration of the present invention, since the cleaning device having any one of the first to fourth configurations is mounted on the image forming apparatus, the streak image, the toner drop, the image flow, and the leak black spot are further increased. Thus, it is possible to perform image formation in which problems such as.

  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 to form 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 accommodated in the developing device 6 include a one-component developer composed of a magnetic styrene-acrylic one component, and a two-component developer composed of a toner component and a carrier. .

  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. 2). 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 input 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 an enlarged side sectional view showing the cleaning device of the present embodiment.

  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. A rubbing roller 21 (cleaning member), a cleaning blade 22 (toner removing means) for removing residual toner on the surface of the photosensitive drum 3, a conveying spiral 23 (toner conveying means) as a toner discharging means, and a rubbing roller A scraper 31 (toner regulating means) for setting the toner on the surface 21 to a predetermined layer thickness, a coil spring 32 (toner disturbing means) for disturbing the toner layer adhering to the surface of the rubbing roller 21, and a toner housing And a urethane seal 33 for preventing waste toner in 7a from leaking to the outside.

  The layer thickness of toner collected from the photosensitive drum 3 is regulated by a scraper 31 (to be described later) on the surface of the rubbing roller 21 by simultaneously rotating a slide roller 21 (to be described later). The cleaning drum 22 is fixed to the housing 7 a via the mounting bracket 37 in a state where the cleaning blade 22 is in contact with the photosensitive drum 3 on the upstream side of the surface of the photosensitive drum 3 with respect to the contact surface with the rubbing roller 21. ing. Here, a cleaning blade 22 made of polyurethane rubber is used, and the free end of the cleaning blade bites into the photosensitive drum 3 at the contact portion, and a predetermined pressure contact with the tangential direction of the photosensitive drum 3 at the contact point. It is attached at an acute angle with force. 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 transport spiral 23 is connected to the motor via a gear (not shown) and is driven to rotate at a predetermined speed. By rotating the transport spiral 23, the toner in the housing 7a collected by the rubbing roller 21 and the cleaning blade 22 is sequentially transported, and from the toner discharge port (not shown) provided on the bottom surface of the housing 7a to the outside of the apparatus. To be discharged. Further, a urethane seal 33 is in contact with the photosensitive drum 3 on the side plate of the housing 7a located on the upstream side in the rotation direction of the photosensitive drum 3 (upper side in FIG. 3) so that the toner does not leak outside from the housing 7a. It is attached at an acute angle with respect to the tangent line.

  FIG. 4 is an enlarged sectional view around the rubbing roller and the scraper. Portions common to those in FIG. 3 are denoted by the same reference numerals and description thereof is omitted.

  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 connected to a drive motor (not shown) of the photoconductive drum 3, and a photoconductive member on a contact surface with the photoconductive drum 3 on a gear (not shown) that rotates on the same rotation shaft as the drum. It is connected via a gear (not shown) so as to rotate in the same direction as the drum 3.

  Examples of the rubbing roller 21 include a structure in which a foam layer made of an elastic material is formed as a roller body around a metal shaft. The material of the roller body may be ethylene propylene rubber (EPDM) in which a foam layer is formed, rubber of another material, or foam rubber body.

  The scraper 31 is in the form of a sheet, and as shown in FIGS. 3 and 4, the support member 38 having an L-shaped cross section disposed above the rubbing roller 21 is downstream in the rotation direction of the photosensitive drum 3. One end is fixed to the short piece on the side, and the other end is a free end and is in contact with the surface of the rubbing roller 21 with a predetermined contact pressure. Further, the scraper 31 has substantially the same length as the length of the rubbing roller 21 in the axial direction (paper surface direction in the drawing). Further, as shown in FIG. 4, the scraper 31 is formed by bonding a scraper 31a (first layer) and a scraper 31b (second layer). Further, the scraper 31 a is in contact with the rubbing roller 21.

The scraper 31a is formed of an elastic material, and here, polyethylene terephthalate (PET) having a contact angle with water (hereinafter referred to as “contact angle”) of 92 ° and a longitudinal elastic modulus of 0.551 kgf / mm ² is used. And By using the scraper 31a, it is possible to suppress the adhesion of toner and to suppress the generation of streak images. In addition, it is possible to prevent the toner layer from becoming too thin and causing toner shortage.

  The scraper 31a that contacts the toner may be made of an elastic material having a contact angle of 70 ° or more. This is because if the contact angle is smaller than 70 °, the toner adheres to the scraper 31a and a streak image is generated, which causes problems in image formation. Other examples of the elastic material include glass (contact angle: 76 °), polycarbonate (PC, contact angle: 87 °), polyvinylidene fluoride (PVDF, contact angle: 88 °), polyimide amide (PIA, contact angle: 90 °), polyimide (PI, contact angle: 92 °), high molecular weight polyethylene (contact angle: 98 °), polytetrafluoroethylene (PTFE, contact angle: 110 °), and the like can be used. In addition, this contact angle was measured using contact angle meter DM100 (made by Kyowa Interface Science Co., Ltd.).

  Here, the thickness of the toner layer is preferably regulated to 50 μm or more and 100 μm or less by the scraper 31. This is because, by regulating the toner layer thickness to 50 μm or more, the toner layer is too thin, the decrease in polishing force caused by the shortage of toner can be suppressed, and the occurrence of image flow can be suppressed. On the other hand, by regulating the toner layer thickness to 100 μm or less, the toner layer is too thick and the toner drop caused by excessive toner and the reduction of the polishing force due to pressure dispersion are suppressed. This is because it can be suppressed.

  However, since the scraper 31a made of PET used here is a low elastic layer made of a material having a small longitudinal elastic modulus, the toner can be sufficiently pressed to regulate the toner layer to a predetermined layer thickness. Therefore, the toner layer may become too thick.

Therefore, in this embodiment, the scraper 31b is used, and a two-layer structure with the scraper 31a is adopted. Scraper 31b is a sheet-like, longitudinal elastic modulus is made of a material having a large than scraper 31a, to the high elastic layer, wherein the modulus of longitudinal elasticity 21000kgf / mm ² in which stainless steel (SUS304, JIS) We will use it. By sticking the scraper 31b to the scraper 31a, the toner can be further pressed against the rubbing roller 21 against the repulsive force of the toner layer when the scraper 31a comes into contact with the toner. Thereby, it can suppress that the layer thickness of a toner layer becomes thick too much.

  Here, the toner layer can be regulated to a predetermined layer thickness by using PET as the scraper 31a which is a low elastic layer and using SUS304 as the scraper 31b which is a high elastic layer. However, as long as the toner layer can be formed to a predetermined layer thickness, the toner layer can be appropriately designed according to the material and thickness of the scraper, and is not particularly limited. For example, ultrahigh molecular weight polyethylene can be used as the scraper 31a, and SUS can be used as the scraper 31b.

  Further, for example, as the scraper 31, a resin having sufficient elasticity to form a predetermined toner layer thickness among the above exemplified resins is selected, or for example, the layer of the scraper 31 is appropriately set. Thus, the scraper 31 can be formed as a single layer. Moreover, it can also be set as the multilayered structure of 3 layers or more as needed.

  A coil spring 32 for disturbing the toner layer adhering to the rubbing roller 21 is provided upstream of the scraper 31 in the rotation direction of the rubbing roller 21 and downstream of the photosensitive drum 3 in the rotation direction. It has been. The coil spring 32 can scrape the surface of the toner layer on the rubbing roller 21 and mix the toner on the outermost surface with the toner on the innermost layer from the outermost surface and the toner collected from the photosensitive drum. The toner layer scraped off by the coil spring 32 is an amount sufficient for the outermost surface of the toner layer to be replaced with another toner, and an amount capable of forming a toner layer having a uniform predetermined layer thickness by the subsequent scraper 31. For example, the entire surface can be scraped off, or only one layer on the outermost surface can be scraped off. These can be appropriately determined depending on the position of the coil spring 32, the rotational speed of the rubbing roller 21, the type of toner, and the like. Can be set.

  By using the coil spring 32 in this way, it is possible to replace the toner located on the outermost surface of the toner layer, which is susceptible to friction, and to suppress the charge-up of the toner layer. Thereby, generation | occurrence | production of a leak black spot can be suppressed. Here, by using the coil spring 32, the toner remaining on the rubbing roller 21 can be disturbed with a simple configuration. However, other members may be used as long as the toner can be disturbed. It can be designed and used as appropriate, and is not particularly limited.

  Further, the toner disturbed by the coil spring 32 is regulated by the scraper 31 and formed as a uniform toner layer with a predetermined layer thickness on the surface of the rubbing roller 21. Therefore, charge-up can be suppressed, and a uniformly formed toner layer can be formed with a predetermined layer thickness.

  Next, the operation of the cleaning device 7 of this embodiment will be described. When the photosensitive drum 3 rotates, the rubbing roller 21 rotates at the same time. Then, toner is supplied from the developing device (see FIG. 1), and after transfer, a part of the toner remaining on the surface of the photosensitive drum 3 is collected by the rubbing roller 21.

  The toner collected on the surface of the rubbing roller 21 is disturbed by the coil spring 32, and then regulated to a predetermined layer thickness by the scraper 32, and is used for polishing the photosensitive drum 3. At this time, the residual toner on the surface of the photosensitive drum 3 is further collected on the rubbing roller 21 and the toner layer is disturbed by the coil spring 32.

  Due to this disturbance, the toner on the outermost layer of the rubbing roller 21 and the toner newly collected from the photosensitive drum 3 are mixed. Alternatively, the toner on the outermost layer is mixed with the toner that is located on the inner layer among the scraped toner. Thereby, the toner on the outermost surface is replaced, and the charge-up of the toner layer can be suppressed.

  Then, after being disturbed by the coil spring 32, the toner layer on the surface of the rubbing roller 21 is uniformly regulated to a predetermined layer thickness by the scraper 31 and is again used for polishing the photosensitive drum 3. This series of operations is repeated until the rotation of the photosensitive drum 3 is stopped.

  On the other hand, the toner on the photosensitive drum 3 that has not been collected by the rubbing roller 21 is scraped off by the cleaning blade 22. Then, together with the toner not regulated by the scraper 31, the toner is discharged from the housing 7 a by the conveying spiral 23.

  The configuration of the scraper 31 and the presence / absence of the coil spring 32 when an image is formed using the image forming apparatus equipped with the cleaning device of the present invention depends on the toner adhesion to the scraper 31, toner dropping from the housing 7 a, and image flow. , And the effect on the occurrence of leaked sunspots.

Configuration using a contact angle is the 65 °, and SUS304 which longitudinal elastic coefficient to form a highly elastic layer is 21000kgf / mm ^2, the contact angle was 92 °, longitudinal elastic modulus 0.551kgf / mm ² PET, which forms a low-elasticity layer, was used, with a total of four types of three comparative examples and one example of the present invention, depending on the presence or absence of a coil spring (see Table 1). The contact angle was measured with the contact angle meter DM100.

  The main configuration of the comparative example is as follows. A SUS304 single layer having a high elastic layer is used as the scraper 31 without a coil spring (Comparative Example 1). A PET single layer having a low elastic layer is used as the scraper 31 without a coil spring (Comparative Example 2). 31 is a three-layer structure using a two-layer structure composed of PET (scraper 31a) and SUS304 (scraper 31b), and without a coil spring (Comparative Example 3). The main configuration of the example of the present invention is one type in which a two-layer structure composed of PET (scraper 31a) and SUS304 (scraper 31b) is used as the scraper 31, and there is a coil spring.

  Then, using a vertical conveyance type color image forming apparatus as shown in FIG. 1, a photosensitive drum 3 having a diameter of 30 mm and a surface layer of α-Si, and a rubbing roller 21 having an outer diameter of 14 mm (shaft diameter of 11 mm) are provided. The circumferential speed difference of the rubbing roller 21 relative to the photosensitive drum 3 was set to + 20%.

  Also, a toner consisting of styrene acrylic and magnetic one component was used, and magnetic jumping development was adopted as a developing method. Under such conditions, a printing durability test was performed in which 20000 originals with a printing rate of 6% were continuously printed, and an endurance test in which 30000 originals were printed completely in a single shot, and the occurrence of the above problems was investigated. .

  The evaluation method is as follows. Concerning toner adhesion, the surface of the scraper 31 is visually confirmed, and the confirmation result is evaluated in two ranks. “○” indicates that toner adhesion is hardly confirmed, and “×” indicates that toner adhesion is confirmed. "

  Concerning toner drop, the toner ejection from the urethane seal 33 was confirmed visually, and the result of the check was evaluated in two ranks. “○” indicates that toner drop is hardly confirmed, and toner adhesion was confirmed. Was marked “x”.

  Regarding the image flow, after standing for 8 hours in a high-temperature and high-humidity environment (32.5 ° C./80%), it was visually confirmed that the halftone image had no white spots (image flow). Evaluation was made based on the rank of the stage. “◯” indicates that the image flow is hardly confirmed in the image, “Δ” indicates that the image flow is slightly confirmed, and “x” indicates that the image flow is remarkable.

  Concerning the leak black spots, the black spots in the image and the leak traces on the photosensitive drum 3 are visually confirmed, and the confirmation result is evaluated in two ranks. What was confirmed as “×”.

  The results are shown in Table 1. Table 1 shows the influence of the configuration of the scraper and the presence or absence of the coil spring on the toner adhesion, toner dropping, image flow, and leak black spot.

  From Table 1, in the case of Comparative Example 1 using the scraper 31 made of SUS304, the toner drop was not confirmed because the toner layer could be thinned. Further, no leak black spot was observed because the outermost layer of the toner layer was peeled off by the contact force of the SUS304 with respect to the rubbing roller 21 and charge-up of the toner layer was suppressed. However, the image flow was slightly confirmed because the polishing force was reduced due to the thin toner. Furthermore, toner adhesion was remarkable because of the large contact angle with water.

  On the other hand, in Comparative Example 2 using the PET scraper 31, no toner adhesion was observed due to the large contact angle. However, since the pressing force against the toner was small, it was confirmed that the toner layer became thicker, the toner dropping was confirmed, or the toner layer was thickened and the polishing power was lowered, so that the image flow was confirmed. Further, leak black spots were observed because the outermost surface of the toner layer was charged up.

  On the other hand, in the case of Comparative Example 3 in which PET and SUS304 are bonded together, is it possible to suppress the toner layer from becoming too thick by using PET as the contact surface side portion of the toner and supporting the PET with SUS304 from the opposite surface side? Neither toner adhesion, toner dropping nor image flow was confirmed. However, with regard to leaked black spots, there was no problem in the endurance test in which continuous printing of 20000 sheets was performed, but when the complete single-shot test of 30000 sheets was performed, the top surface was charged up, or 3000 sheets from the start leaked to the drum surface. A sunspot has occurred. In the complete single test, it can be considered that the toner layer is charged up because the supply of toner from the developing device 6 is less than continuous printing and the outermost surface of the toner is more susceptible to friction.

  Therefore, when PET and SUS304 were bonded together and the coil spring 32 was disposed as in the example of the present invention, toner adhesion, toner dropping, and image flow were not observed. Further, regarding the leak black spot, by using the coil spring 32, it was not confirmed in the continuous printing test of 20000 sheets or in the durability test of 30000 sheets of complete single shot. This is because, by using the coil spring 32, the toner layer can be disturbed before the toner is regulated to a predetermined layer thickness, and the outermost surface of the toner layer is replaced, thereby suppressing the charge-up on the outermost surface of the toner layer. It is thought that it was because it was done.

  As a result, the contact portion with the toner is made of an elastic material having a contact angle with water of 70 ° or more, and the scraper 31 that can regulate the toner layer to a predetermined layer thickness is used. By disposing the coil spring 32 on the upstream side in the rotation direction and on the downstream side in the rotation direction with respect to the photosensitive drum 3, the toner layer on the rubbing roller 21 can be disturbed and the toner on the outermost surface can be replaced. As a result, it has been found that the toner charge-up can be suppressed, and the toner layer can be regulated to a uniform toner layer thickness suitable for polishing. Accordingly, it has been found that image quality deterioration such as streak image, toner drop, image flow, and leaked black spot in image formation can be further suppressed as compared with the conventional art.

  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-described embodiment, the present invention is applied to an image forming apparatus for monochrome printing, but the present invention can be applied to other image forming apparatuses and is not particularly limited. For example, the present invention can also be applied to color printers such as monochrome copying machines, intermediate transfer tandem image forming apparatuses, and direct transfer tandem image forming apparatuses.

  The present invention provides a housing arranged to have an opening on the image carrier side, a part of residual toner on the surface of the image carrier, which is arranged in the opening and rotatably contacts the image carrier. A cleaning member that supplies a portion of the recovered toner to the surface of the image carrier and polishes the surface, and is disposed downstream of the cleaning member in the rotation direction of the surface of the image carrier. A toner removing unit that scrapes off residual toner that has not been collected by the cleaning member; and a toner conveying unit that conveys the toner collected and scraped off from the surface of the image carrier by the cleaning member and the toner removing unit. In the cleaning device provided, at least the contact portion with the toner is made of an elastic material having a contact angle with respect to water of 70 ° or more, and the toner layer attached to the surface of the cleaning member has a predetermined layer thickness. Toner regulating means that can be controlled, and toner that is disposed on the upstream side in the rotational direction of the cleaning member with respect to the toner regulating means and on the downstream side in the rotational direction with respect to the image carrier, and adheres to the cleaning member And a toner disturbing means for disturbing the layer.

  Accordingly, the toner layer of the cleaning member can be prevented from being charged up, and a uniform toner layer can be formed on the surface of the cleaning member with a predetermined layer thickness. Problems in image formation such as flow and leaked black spots can be further suppressed as compared with the prior art.

  Further, by using a coil spring as the toner disturbing means, it is possible to suppress the above-mentioned problems in image formation with a simpler configuration. Furthermore, by controlling the toner layer thickness to 50 μm or more and 100 μm or less using the toner regulating means, it is possible to further suppress problems in image formation due to the toner layer being too thin or too thick. .

  Further, the toner regulating means has a two-layer structure, and the second layer on the opposite surface side portion is made of a material having a larger longitudinal elastic modulus than the first layer on the toner contact surface side portion. Accordingly, the toner layer can be uniformly regulated to a layer thickness appropriate for polishing without making the member complicated.

  By mounting such a cleaning device on the image forming apparatus, it is possible to perform image formation that further suppresses problems such as streak images, toner drop, image flow, and leaked black spots.

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 around the cleaning apparatus of this invention. These are side surface sectional views which show the structure of the cleaning apparatus of this invention. These are expanded side sectional drawings which show the structure around the rubbing roller, scraper and coil spring of the cleaning device of the present invention.

Explanation of symbols

3 Photosensitive drum 6 Developing device 7 Cleaning device 7a Housing 21 Rub roller (cleaning member)
22 Cleaning blade (toner removal means)
23 Conveying spiral (toner conveying means)
31 Scraper (Toner regulating means)
31a Scraper (toner regulating means, first layer)
31b Scraper (toner regulating means, second layer)
32 Coil spring (toner disturbance means)
33 Urethane seal 100 Image forming device

Claims (5)

A housing arranged to have an opening on the image carrier side; and a housing arranged in the opening, rotatably contacting the image carrier and collecting a part of residual toner on the surface of the image carrier. A cleaning member that supplies a part of the collected toner to the surface of the image carrier and polishes the surface, and is disposed downstream of the cleaning member in the rotation direction of the surface of the image carrier, and is collected by the cleaning member. A cleaning device comprising: a toner removing unit that scrapes off the residual toner that has not been removed; and a toner conveying unit that conveys the toner collected and scraped off from the surface of the image carrier by the cleaning member and the toner removing unit. In
At least a contact portion with the toner is made of an elastic material having a contact angle with water of 70 ° or more, and a toner regulating means capable of regulating the toner layer attached to the surface of the cleaning member to a predetermined layer thickness;
A toner scrambler that is disposed upstream of the cleaning member in the rotational direction of the cleaning member and downstream of the image bearing member in the rotational direction, and turbulently adheres the toner layer adhering to the cleaning member. When,
A cleaning device comprising:   The cleaning device according to claim 1, wherein the toner disturbing unit is a coil spring.   The cleaning device according to claim 1, wherein the toner regulating unit regulates the toner layer attached to the surface of the cleaning member to 50 μm or more and 100 μm or less.   The toner regulating means is formed of a sheet-like member having a two-layer structure comprising a first layer on the side in contact with the toner and a second layer on the side opposite to the contact surface. The cleaning apparatus according to claim 1, wherein the second layer is made of a material having a larger longitudinal elastic modulus than the first layer.   An image forming apparatus on which the cleaning device according to claim 1 is mounted.