JP3945783B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a cleaning device having a brush roller.

  2. Description of the Related Art Conventionally, a cleaning device that cleans an object to be cleaned has been widely used in machines and devices in various technical fields. For example, in an image forming apparatus configured as a copying machine, a printer, a facsimile, or the like, a cleaning device that cleans the surface of the image carrier, a cleaning device that cleans the peripheral surface of the charging roller that charges the image carrier, A cleaning device for cleaning the surface of the transfer body or the transfer belt is used.

  As such a cleaning device, a cleaning device having a brush that contacts the surface of the object to be cleaned, and a brush roller that rotates while the brush contacts the object to be cleaned is widely used (for example, Japanese Patent Laid-Open No. Hei 7). -140763). A conventional brush roller of this type of cleaning apparatus is configured so that the cleaning ability of the brush in the longitudinal direction is uniform, and thereby, the entire surface of the object to be cleaned can be uniformly cleaned. However, depending on the device or machine in which the object to be cleaned is incorporated, the surface of the object to be cleaned in the direction orthogonal to the direction of movement of the surface of the object to be cleaned is not uniform. May be more noticeable than dirt. In such a case, if the cleaning ability in the longitudinal direction of the brush roller is constant, there is a possibility that the surface portion of the object to be cleaned that is heavily soiled cannot be sufficiently cleaned. In view of this, it is conceivable to increase the cleaning ability of the brush roller over the entire length thereof so that the entire surface of the object to be cleaned can be efficiently cleaned. However, when the brush roller is configured in this way, the surface of the object to be cleaned is excessively rubbed, and the surface of the object to be cleaned is worn out early and its life is shortened. I can't escape.

  The present invention has been made on the basis of the above-mentioned novel recognition, and the object of the present invention is to improve the cleaning ability of the surface of the object to be cleaned even when the surface of the object to be cleaned is not constant. An object of the present invention is to provide an image forming apparatus provided with a cleaning device having a brush roller capable of suppressing the problem of shortening the life of an object to be cleaned.

  In order to achieve the above object, the present invention exposes a charging device, an image carrier charged by the charging device, and an image carrier after charging to form an electrostatic latent image on the image carrier. A developing device that visualizes the electrostatic latent image as a toner image, and an intermediate transfer member to which the toner image on the image carrier is transferred. A developer carrying member that carries and conveys the developer having the toner and the carrier, a first developer carrying member that is disposed substantially parallel to the developer carrying member and is driven to rotate; And a second developer conveying member that is disposed substantially parallel to the first developer conveying member and is driven to rotate, and the development conveyed in the first direction by the second developer conveying member. The longitudinal direction of the first developer conveying member from one end side in the longitudinal direction of the second developer conveying member The developer delivered to one end side and delivered to the first developer transport member is transported by the first developer transport member in a second direction opposite to the first direction. The conveyed developer is transferred from the other longitudinal end of the first developer conveying member to the other longitudinal end of the second developer conveying member, and received by the second developer conveying member. The transferred developer is transported in the first direction by the second developer transport member, the developer is circulated and transported, and is transported in the second direction by the first developer transport member. The developer is supplied to the developer carrier, and the supplied developer is carried on the developer carrier and conveyed to a development area between the developer carrier and the image carrier. The conveyed developer is used for visualization of the electrostatic latent image, and the second developer conveying member In the image forming apparatus in which the toner to which the additive is added is replenished in the developer further conveyed, the image forming apparatus has a cleaning device that removes the transfer residual toner adhering to the intermediate transfer member, and the cleaning device includes: The brush includes a brush roller that rotates while contacting the surface of the intermediate transfer member to clean the intermediate transfer member, and corresponds to one end side of the first developer transport member and the second developer transport member. An image forming apparatus is proposed in which the brush roller is configured so that a portion on one end side in the longitudinal direction of the brush roller has a higher cleaning ability than other brush roller portions (claim 1).

  In order to achieve the above object, the present invention exposes a charging device, an image carrier charged by the charging device, and an image carrier after charging to form an electrostatic latent image on the image carrier. An exposure device that performs the development, a developing device that visualizes the electrostatic latent image as a toner image, and a transfer belt that carries and conveys a transfer material onto which the toner image on the image carrier is transferred, The developing device includes a developer carrying member that carries and conveys a developer having a toner and a carrier to which an additive is added, and a rotation support that is disposed substantially parallel to the developer carrying member. 1 developer conveying member, and a second developer conveying member that is arranged substantially parallel to the first developer conveying member and is driven to rotate. The second developer conveying member The developer conveyed in the first direction is moved forward from one end side in the longitudinal direction of the second developer conveying member. The developer transferred to one end side in the longitudinal direction of the first developer transport member, and the developer transferred to the first developer transport member is opposite to the first direction by the first developer transport member. The developer conveyed in the second direction is transferred from the other longitudinal end of the first developer transport member to the other longitudinal end of the second developer transport member, The developer delivered to the second developer transport member is transported in the first direction by the second developer transport member, the developer is circulated and transported, and the first developer transport is performed. The developer conveyed in the second direction by the member is supplied to the developer carrier, and the supplied developer is carried on the developer carrier and the developer carrier, the image carrier, And the developer thus conveyed is used for visualization of the electrostatic latent image. In the image forming apparatus in which the toner added with the additive is replenished in the developer conveyed by the second developer conveying member, the image forming apparatus has a cleaning device for removing the toner adhering to the transfer belt. The cleaning device includes a brush roller for cleaning the transfer belt by rotating while a brush is in contact with the surface of the transfer belt, and one end of the first developer transport member and the second developer transport member. An image forming apparatus is proposed, characterized in that the brush roller is configured such that a portion on one end side in the longitudinal direction of the brush roller corresponding to the side has higher cleaning ability than other brush roller portions ( Claim 2).

  Furthermore, in the image forming apparatus according to claim 1 or 2, the bending rigidity of the brush fiber of the brush roller portion having the high cleaning ability is set higher than the bending rigidity of the brush fiber of the brush roller portion having the low cleaning ability. It is advantageous if it is made (Claim 3).

  Further, in the cleaning device according to any one of claims 1 to 3, when the outer diameter of the brush roller portion having a high cleaning ability is set smaller than the outer diameter of the brush roller portion having a low cleaning ability. It is advantageous (claim 4).

  ADVANTAGE OF THE INVENTION According to this invention, even if the dirt state of the to-be-cleaned body surface is not constant, the cleaning capability with respect to the surface can be improved, and the malfunction by which the lifetime of the to-be-cleaned body is shortened can be suppressed.

  Embodiments in which the present invention is applied to a cleaning device for an image forming apparatus will be described below in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of an image forming apparatus. The image forming apparatus shown here is configured as an electronic copying machine, a printer, a facsimile, or a multifunction machine having at least two of these functions. is there.

  The image forming apparatus shown in FIG. 1 has an image carrier 1 configured as a drum-shaped photoreceptor, and the image carrier 1 is rotationally driven in the direction of arrow A as the image forming operation starts. At this time, the charging roller 2, which is an example of a charging device disposed opposite to the surface of the image carrier, is rotated in the direction of arrow B by a driving device (not shown) or following the movement of the surface of the image carrier 1. . The charging roller 2 includes a cored bar 3 and a resistance layer 4 fixed around the cored bar 3. When the charging roller 2 rotates as described above, a charging voltage having a predetermined polarity is applied to the cored bar 3. The surface of the image carrier 1 is charged with a predetermined polarity.

  The surface of the charged image carrier 1 is irradiated with a light-modulated laser beam LB emitted from a laser writing unit 30 which is an example of an exposure apparatus, whereby an electrostatic latent image is formed on the surface of the image carrier. The This electrostatic latent image is visualized as a toner image by the developing device 5.

  Further, a transfer belt 8 driven in the direction of arrow E is opposed to the image carrier 1, and a transfer sheet P, which is an example of a transfer material fed from a paper supply unit (not shown), 8 is carried and conveyed. When the transfer paper P passes through the transfer region between the image carrier 1 and the transfer belt 8, a transfer voltage is applied to the transfer device 9 disposed opposite to the image carrier 1 with the transfer belt 8 interposed therebetween, whereby the image carrier The toner image formed on the body surface is electrostatically transferred onto the transfer paper P. It is also possible to transfer the toner image formed on the image carrier onto a transfer material made of an intermediate transfer member, and transfer the transferred toner image onto a transfer paper as the final transfer material.

  The untransferred toner adhering to the surface of the image carrier after the toner image is transferred is scraped and removed by a cleaning member composed of a brush roller 10 and a cleaning blade 11 in pressure contact with the surface of the image carrier. On the other hand, the transfer paper P to which the toner image has been transferred passes through a fixing device (not shown), and at this time, the toner image is fixed on the transfer paper by the action of heat and pressure.

  In the image forming apparatus shown in FIG. 1, the image carrier 1, the charging roller 2, the brush roller 10, and a brush roller 12 to be described later are rotatably assembled to the unit case 13, and the base end portion of the cleaning blade 11 is The unit process 13 is fixed to the unit case 13, and an integrated process cartridge 14 is constituted by these elements. The process cartridge 14 can be pulled out along the guide rail 15 fixed to the main body of the image forming apparatus or pushed into the back side to load the process cartridge 14 at a predetermined position. An image carrier cleaning device 17 for cleaning the surface of the image carrier is constituted by the brush roller 10, the cleaning blade 11, and the cleaning case 16 constituted by a part of the unit case 13.

  As described above, the charging roller 2 is used to charge the image carrier 1 while facing the image carrier. As shown in FIG. 1, the roller 2 may be in pressure contact with the surface of the image carrier 1, but a minute gap is formed from the surface of the image carrier 1, and the roller 2 is positioned in a non-contact state with respect to the image carrier. You may do it.

  As described above, the image forming apparatus of this example exposes the charging device, the image carrier charged by the charging device, and the charged image carrier to form an electrostatic latent image on the image carrier. And a developing device that visualizes the electrostatic latent image as a toner image. The developing device is configured as follows.

  2 is a cross-sectional plan view taken along the line II-II in FIG. 1, and as is apparent from FIGS. 1 and 2, the developing device 5 is a dry developer D (not shown in FIG. 2). ) And a developer carrier 7 in which a magnet (not shown) is fixedly arranged. Here, a developer carrier made of a developing roller is used, but a developer carrier made of an endless belt can also be used. The developer D used here is a two-component developer having a toner externally added with an additive and a magnetic carrier. The developer carrier 7 is rotationally driven in the direction indicated by the arrow in FIG. 1, and the developer D supplied to the peripheral surface of the developer carrier 7 is caused by the magnetic force of the magnet to cause the developer carrier. An electrostatic latent image formed on the image carrier 1 is formed on the image carrier 1 by the toner in the developer carried on the peripheral surface of the toner 7 and conveyed in the direction of the arrow, and carried between the developer carrier 7 and the image carrier 1. The latent image is visualized as a toner image. As described above, the developer carrying member is used to carry and carry the developer having the toner and the carrier to which the additive is externally added.

  In addition, the developing device 5 of the present example is arranged substantially parallel to the developer carrier 7 and is driven to rotate, and the first developer transport member 31 is rotated with respect to the first developer transport member 31. And a second developer conveying member 32 which is arranged substantially in parallel and is driven to rotate. In the illustrated example, these developer conveying members 31 and 32 are constituted by conveying screws. As is clear from FIG. 2, the first and second developer transport members 31 and 32 and the developer carrier 7 are axially supported at their respective end portions in the axial direction on the side walls of the developing case 6. It is rotationally driven around its central axis by a driving device (not shown). The first and second developer conveying members 31 and 32 are disposed in the first and second spaces S1 and S2 in the developing case 6 defined by the partition wall 33 disposed therebetween.

  Here, one of the end regions in the longitudinal direction of the first and second developer transport members 31 and 32 is one end side, and the other is the other end side. In the illustrated example, the developer transport member 31 and FIG. Assume that the right end side of 32 is one end side, and the left end side is the other end side. In FIG. 2, reference numerals E1 and E2 are attached to one end side and the other end side thereof. Further, each end region in the axial direction of the image carrier 1 corresponding to one end side E1 and the other end side E2 of the first and second developer transport members 31 and 32, and each end portion in the longitudinal direction of the charging roller 2 The region and each end region in the longitudinal direction of the brush roller 12 are also referred to as one end E1 and the other end E2, respectively. The partition wall 33 does not exist on the one end side E1 and the other end side E2 of the first and second developer transport members 31, 32, and the portions where the partition wall 33 does not exist are the first and second openings 34, 35. The first and second spaces S1, S2 communicate with each other through the openings 34, 35.

  The developer in the second space S2 is transported in the first direction indicated by the arrow J1 in FIG. 2 by the rotation of the second developer transport member 32. In this way, the developer conveyed in the first direction J1 by the second developer conveying member 32 passes through the first opening 34 from the longitudinal direction one end E1 of the second developer conveying member 32. The first developer conveying member 31 is delivered to one end E1 in the longitudinal direction. Then, the developer delivered to the first developer transport member 31 is transported by the first developer transport member 31 in the second direction J2 opposite to the first direction J1, and is transported. The transferred developer is transferred from the other end E2 in the longitudinal direction of the first developer transport member 31 to the other end E2 in the longitudinal direction of the second developer transport member 32 through the second opening 35, and The developer delivered to the second developer transport member 32 is transported in the first direction J1 by the second developer transport member 32. In this way, the developer is stirred while being circulated and the toner and the carrier are triboelectrically charged with opposite polarities.

  The developer conveyed in the second direction J2 by the first developer conveying member 31 is supplied to the peripheral surface of the developer carrier 7, and as described above, the supplied developer is The developer is carried on the developer carrying member 7 and conveyed to a developing area between the developer carrying member 7 and the image carrier 1, and the conveyed developer is used for visualizing the electrostatic latent image. The The developer that has passed through the developing region is separated from the developer carrier 7 and further conveyed in the second direction J2 by the first developer conveying member 31 and circulated.

  When a decrease in the toner concentration of the developer in the developing case 6 is detected by a sensor (not shown), the toner sent from the toner container of the toner supply device (not shown) is moved above the second developer transport member 32. The toner is replenished into the developing case 6 from the toner replenishing port formed in the developing case portion. FIG. 2 shows the position of the toner supply port 36 by a chain line.

  The toner replenished to the developing case 6 as described above first falls on the second developer conveying member 32, and is agitated by the second developer conveying member 32. While mixing with the developer conveyed in the direction J1, the developer moves together with the developer to the first space S1 through the first opening 34. As described above, in the developing device 5 of this example, the toner added with the additive is supplied to the developer conveyed by the second developer conveying member 32 and conveyed.

  By the way, when the image forming operation is performed as described above, the cleaning device 17 removes the transfer residual toner on the image carrier, but it is difficult to remove all the toner, and a small amount of toner is removed from the cleaning blade 11. Slip through. The foreign matter such as the toner slipped through in this way and the toner floating in the image forming apparatus main body adheres to the peripheral surface of the charging roller 2. If this is left unattended, uneven charging or poor charging of the image carrier occurs, and the image quality of the toner image formed on the image carrier deteriorates.

  Therefore, the image forming apparatus of the present example is provided with a charging roller cleaning device 18 including the brush roller 12 described above. The charging device is composed of a charging roller 2 disposed so as to face the image carrier 1, and a cleaning device 18 for cleaning the peripheral surface of the charging roller 2 is provided.

  The brush roller 12 extends in parallel to the charging roller 2, and as shown in FIGS. 3 and 4, a core shaft 19 made of a rigid body such as metal or hard resin, and a base end on the peripheral surface of the core shaft 19. It has the brush 20 which consists of many fibers by which the part was fixed. The brush 20 is provided over the entire circumference of the core shaft 19 in the range indicated by the symbol W in FIG. As shown in FIGS. 1 and 3, the brush roller 12 rotates while contacting the surface of the object to be cleaned, in this example, the charging roller 2, to clean the surface of the charging roller 2.

  The brush roller 12 may be pressed against the peripheral surface of the charging roller 2 by a pressing means such as a compression spring (not shown), or the brush roller 12 may be rotationally driven by a driving device (not shown). The brush roller 12 is rotated in the direction of arrow G by the brush 20 abutting on the surface of the object to be cleaned, that is, the surface of the charging roller 2 by the weight of the brush roller 12, and following the movement of the surface of the object to be cleaned. Are arranged to be.

  Specifically, as shown in FIGS. 1 and 3, bearing members 21 are provided on the side plate 13A on the back side of the unit case 13 and the side plate (not shown) on the near side, as shown by the chain line in FIG. Each of the bearing members 21 is fixed, and a guide slot 22 having an open lower portion is formed in each of the bearing members 21, and each longitudinal end portion of the core shaft 19 of the brush roller 12 is rotatable in each guide slot 22 and the guide slot 22 is rotatable. It fits along the slot 22 so as to be slidable in the direction of arrow F (direction approaching or separating from the surface of the object to be cleaned). The width of each guide slot 22 is set slightly larger than the diameter of each end portion of the core shaft 19, so that each end portion of the core shaft 19 can be fitted into each guide slot 22 without rattling.

  Since the brush roller 12 is located in the upper region of the charging roller 2 and each end portion of the core shaft 19 is slidably fitted in the guide slot 22, the brush roller 12 has the brush 20 The roller 12 comes into contact with the surface of the charging roller 2 due to its own weight. In addition, since each end of the core shaft 19 is rotatably fitted in the guide slot 22, when the charging roller 2 rotates in the arrow B direction, the brush roller 12 is driven by the movement of the surface of the charging roller 2. And can be rotated in the direction of arrow G. The brush roller 12 rotates with the rotation of the charging roller 2, and at this time, the brush 20 in contact with the surface of the charging roller 2 removes the toner adhering to the surface of the charging roller 2 and cleans the surface. is there.

  By the way, as described above, the brush roller of the conventional cleaning device is configured so that the cleaning ability in the longitudinal direction is uniform, which causes the following drawbacks.

  As described above, the fresh toner replenished from the toner replenishing device (not shown) into the developing case 6 of the developing device 5 is transported by the second developer transport member 32, and the first developer transport member 31. Is passed on. The developer containing fresh toner is gradually transferred from one side in the longitudinal direction of the developer carrier 7 to the peripheral surface of the developer carrier 7.

  The problem here is the additive contained in the toner. Various additives are used to increase the fluidity of the toner and improve the image quality, but these additives are more likely to migrate to the surface of the image carrier than the resin constituting the toner particles. There are also things. For this reason, the additive in the fresh toner from which the developer has been transferred from the second developer conveying member 32 to the first developer conveying member 31 is the developer carrier as shown by the broken line arrow I in FIG. 7 immediately attaches to the peripheral surface of the image carrier 7, and the additive moves to the surface of the image carrier 1 at an early stage. In this way, on the peripheral surface of the image carrier, a larger amount of additive adheres to one end side in the axial direction of the image carrier corresponding to one end side of the developer transport members 31 and 32 than the other portions. The additive passes through the cleaning device 17 and adheres to the peripheral surface of the charging roller 2. Therefore, a large amount of additive adheres to one end side portion of the charging roller 2 corresponding to the one end side E1 of the first developer conveying member 31 and the second developer conveying member 32, and one end side of the charging roller 2 The amount of dirt increases, and the amount of dirt decreases as it goes to the other end side of the charging roller 2. Therefore, with a conventional brush roller having a constant cleaning capability in the longitudinal direction, the dirt on one end of the charging roller 2 cannot be removed sufficiently, and the charging capability for the image carrier portion corresponding to the charging roller portion is reduced. As a result, the image carrier cannot be charged uniformly, which may deteriorate the image quality and generate an abnormal image.

  Therefore, the brush roller 12 of the cleaning device 18 of the present example is configured so that the cleaning ability of the brush 20 in the longitudinal direction is different. More specifically, a portion of the brush roller 12 on one end side E1 (FIG. 4) corresponding to one end side E1 of the first developer transport member 31 and the second developer transport member 32 is another brush. The brush roller 12 is configured so that the cleaning ability is higher than that of the roller portion.

  With the above-described configuration, the charging roller 2 having a large amount of dirt locally can be uniformly cleaned over the entire length thereof, and uneven charging of the image carrier 1 can be eliminated, and a high-quality image can be formed. Further, since the cleaning capability is not enhanced over the entire length of the brush roller 12, the brush does not exert an excessively large rubbing force on the charging roller portion with less dirt, and the charging roller portion can be quickly moved. It is possible to prevent the problem of wear.

  Various specific configurations for changing the cleaning ability of the brush roller 12 can be employed. For example, the bending rigidity of the brush fibers on one end E1 in the longitudinal direction of the brush roller 12 shown in FIG. 4 is set to be higher than the bending rigidity of the brush fibers in other portions. Since the brush having a large bending rigidity strongly hits the peripheral surface of the charging roller 2, its cleaning ability is enhanced, and dirt on the peripheral surface of the charging roller can be efficiently removed. In that case, you may comprise so that the bending rigidity of the brush 20 may become low gradually toward the other end side E2 from the one end side E1 of the brush roller 12, or the brush roller 12 may be comprised in several part W1 in the longitudinal direction. , W2, W3, W4, and W5, and the bending rigidity of the brush 20 can be reduced sequentially from the portion W1 to the portion W5. That is, the height of the bending rigidity of the brush is set to W1> W2> W3> W4> W5.

  As described above, by setting the bending rigidity of the brush fiber in the brush roller portion having a high cleaning ability to be higher than the bending rigidity of the brush fiber in the brush roller portion having a low cleaning ability, the brush is cleaned in the longitudinal direction of the brush roller. Different abilities can be used.

  The brush cleaning in the longitudinal direction of the brush roller is performed by setting the outer diameter of the brush roller portion having a high cleaning ability to be smaller than the outer diameter of the brush roller portion having a low cleaning ability instead of or in addition to the above-described configuration. You can also vary abilities. Specifically, as illustrated in FIG. 5, the brush roller 12 is configured such that the outer diameter of the core shaft 19 of the brush roller 12 gradually increases from one end side E1 in the longitudinal direction toward the other end side E2. To do. As a result, the weight of the other end side E2 of the brush roller 12 is greater than that of the one end side E1, and the pressure at which the brush roller 12 contacts the surface of the charging roller 2 is greater on the other end side E2 than on the one end side E1. growing. For this reason, the other end side E <b> 2 of the brush roller 12 rotates with the charging roller 2, and the surface linear velocity of the other end side E <b> 2 of the brush roller 12 becomes substantially equal to the surface linear velocity of the charging roller 2. Therefore, the surface linear velocity of the one end E1 of the brush roller 12 having an outer diameter smaller than that of the other end E2 of the brush roller 12 is slower than the surface linear velocity of the charging roller 2, and there is a linear velocity difference between the two. The brush portion on the one end side E1 of the brush roller 12 is rubbed against the charging roller 2, and its cleaning ability is higher than that on the other end side E2. Thereby, a large amount of dirt adhering to one end side of the charging roller 2, that is, the additive can be efficiently removed.

  Even when the brush roller 12 is not rotated around the charging roller 2 but is actively rotated by a driving device, for example, the surface linear velocity of the other end side E2 of the brush roller 12 is the charging roller. If the brush roller 12 is driven so as to be approximately equal to the surface linear velocity of 2, the same result as described above can be obtained.

  In any of the above-described examples, the rubbing force between the other end side E2 of the brush roller 12 and the other end side of the charging roller 2 with little dirt is kept small, so that the peripheral surface portion of the charging roller 2 with little dirt is placed. An excessively large rubbing force is not exerted, and a problem that the wear is accelerated can be prevented.

  Note that the brush roller 12 of the illustrated cleaning device 18 is not driven to rotate by the driving device, but rotates following the rotation of the charging roller 2, so that a driving device for rotating the brush roller 12 is not required. As a result, the configuration of the cleaning device 18 can be simplified and the cost can be reduced. In addition, since the brush 20 does not hit the surface of the charging roller 2 excessively, wear on the surface of the charging roller 2 can be suppressed.

  Further, the brush roller in a state where the brush roller 12 is in contact with the charging roller 2 from the sum of the radius of the brush roller 12 and the radius of the charging roller 2 in a state where the brush roller 12 is not in contact with the charging roller 2. The value obtained by subtracting the distance between the center of 12 and the center of the charging roller 2 is the amount of biting of the brush 20, but if the amount of biting becomes too large, the fibers of the brush 20 deteriorate early and this is permanent. If the deformation occurs, the brush falls, and the brush bite amount is too small, the cleaning efficiency of the surface of the charging roller 2 is lowered. The amount of biting of the brush can be regulated by adjusting the relative position of the two so that the distance between the center of the brush roller and the center of the charging roller is constant by the regulating means, but if such a regulating means is provided, Accordingly, the cost of the cleaning device increases and the structure becomes complicated.

  On the other hand, in the cleaning device 18 of this example, the brush roller 12 is configured to abut against the surface of the charging roller 2 by its own weight, so that a desired brush can be obtained only by adjusting the weight of the brush roller 12. The amount of biting can be obtained, and the regulation means can be omitted. Thereby, simplification of the structure of the cleaning device 18 and cost reduction can be achieved.

  The length of the fibers of the brush 20 can be set as appropriate, but it is desirable to set the length to 2 mm or less, particularly 0.4 to 0.6 mm. The length of this fiber is the length of the free fiber portion excluding the fiber portion fixed to the core shaft 19. If the length of the fiber is shortened in this way, the bending moment acting on the base end portion of the fiber that is elastically bent and deformed by being pressed against the surface of the charging roller 2 can be reduced. As a result, the occurrence of brush fall (permanent deformation) can be more effectively suppressed over a long period of time, and the life of the brush roller 12 can be extended. When the fiber length of the brush 20 is longer than 2 mm, the distance between the fibers at the tip end of the fiber increases, so that the load applied to each fiber in contact with the surface of the charging roller 2 increases, thereby increasing the brush. However, such a problem can be avoided by setting the fiber length to 2 mm or less.

  In order to remove the toner adhering to the tip of the brush of the brush roller, the brush may be applied to the flicker. However, if the length of the fiber of the brush 20 is shortened as described above, FIG. As shown in FIG. 3, the toner attached to the tip of the brush can be removed without hitting the brush 20 against the flicker. The reason for this is not necessarily clear, but if the fibers are as short as 2 mm or less, the fibers that are elastically deformed by being pressed against the surface of the charging roller 2 are caused by the rotation of the brush roller 12 from the charging roller 2. When it leaves, it is elastically restored to its original form instantly, and this is considered to be because the toner adhering to the tip of the fiber jumps out of the fiber due to the impact at this time.

The thickness and density of the fibers of the brush 20 can be set as appropriate. When the thickness is set to 2 denier or less and the density of the fibers is set to 20000 / cm ² or more, particularly 30000 / cm ² , the charging roller A large number of fibers come into contact with the surface of 2, whereby the load applied to each fiber can be reduced. This also can prevent the brush from falling over a long period of time. Further, when the density of the fibers is increased in this way, the number of fibers contacting the surface of the charging roller increases, so that the surface of the charging roller 2 can be efficiently cleaned and the unevenness of the stain can be eliminated. It is possible to always form a high-quality image on the top.

  In addition, the weight of the brush roller 12 can be set as appropriate. In particular, when the weight is set to 50 g or more and 200 g or less, an appropriate amount of biting of the brush 20 can be ensured and the brush roller 12 can be smoothly rotated. It becomes possible. If the weight of the brush roller 12 is smaller than 50 g, the amount of biting of the brush becomes too small, and the cleaning efficiency of the surface of the charging roller 2 is lowered. If the weight is larger than 200 g, the amount of biting of the brush is excessively large. It becomes easy to promote the fall of the brush.

  The brush 20 can be fixed to the core shaft 19 by an appropriate method. In particular, when the fiber base end portion of the brush 20 is fixed to the peripheral surface of the core shaft 19 of the brush roller by the electrostatic flocking method, the core shaft 19, short fibers can be planted with high density. Thereby, it is possible to prevent the brush from falling over a long period of time and to extend the life of the brush roller 12.

  For example, an adhesive is applied to the range W (FIG. 4) of the core shaft 19, the base end portions of a large number of fibers are electrostatically attached to the adhesive, and the base end portions of the fibers are passed through the adhesive. Can be fixed to the core shaft 19.

  The material of the brush fibers can also be selected as appropriate. However, according to experiments, particularly when the fibers are composed of a resin such as nylon 66 or PET (polyethylene terephthalate), the brush can be effectively prevented from falling and an appropriate amount of biting can be obtained. It has been confirmed.

  Further, if the brush fibers are made of a material capable of electrostatically attracting the toner adhering to the charging roller 2 to the brush, the cleaning efficiency of the surface of the charging roller 2 can be further enhanced.

  When the object to be cleaned is composed of a rotating body formed in a columnar shape like the charging roller 2 shown in FIG. 1, as shown in FIG. 6, a horizontal line H passing through the rotation center O of the rotating body 2A. If the brush roller 12 is brought into contact with the range S of the rotating body circumferential surface above the brush 20, the brush 20 can be brought into contact with the rotating body without any trouble due to its own weight.

  The example of the cleaning device in the case where the member to be cleaned is the charging roller 2 that faces the image carrier 1 and charges the image carrier 1 has been described above, but various members to be cleaned other than the charging roller 2 are cleaned. Therefore, the cleaning devices having the above-described configurations can be used. For example, the image forming apparatus shown in FIG. 1 has a cleaning device 17 that cleans the surface of the image carrier after the toner image formed on the image carrier is transferred to a transfer material. The brush roller 10 is configured in the same manner as the brush roller 12 described above, and each configuration described above can be applied to the cleaning device 17 for the image carrier. In that case, the portion on the one end side in the longitudinal direction of the brush roller 10 corresponding to the one end side E1 of the first developer conveying member 31 and the second developer conveying member 32 is more cleaning ability than the portions of the other brush rollers 10. The brush roller 10 is configured so as to be high.

  In addition, in order to remove the transfer residual toner attached on the intermediate transfer body onto which the toner image on the image carrier is transferred, a cleaning device having the brush roller can be used. The above-described configurations can also be employed in a cleaning device that removes toner adhering to the transfer belt 8 that carries and conveys the transfer material onto which the toner image is transferred.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus. It is sectional drawing of the image development apparatus cut | disconnected along the II-II line | wire of FIG. It is an enlarged view of a brush roller. It is a front view of a brush roller. It is a front view which shows the other example of a brush roller. It is a figure explaining the arrangement position of the brush roller with respect to a to-be-cleaned body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image carrier 5 Developing apparatus 7 Developer carrier 31 1st developer conveyance member 32 2nd developer conveyance member E1 One end side E2 The other end side D Developer J1 1st direction J2 2nd direction

Claims (4)

A charging device; an image carrier charged by the charging device; an exposure device that exposes the charged image carrier to form an electrostatic latent image on the image carrier; and A developing device that visualizes a toner image and an intermediate transfer member to which a toner image on the image carrier is transferred. The developing device includes a developer having a toner and a carrier to which an additive is added. A developer carrying member carried and carried, a first developer carrying member that is arranged substantially parallel to the developer carrying member and driven to rotate, and substantially the first developer carrying member. A second developer conveying member arranged in parallel and driven to rotate, and the developer conveyed in the first direction by the second developer conveying member is the second developer conveying member. From one end in the longitudinal direction to one end in the longitudinal direction of the first developer conveying member. The developer delivered to the transport member is transported in the second direction opposite to the first direction by the first developer transport member, and the transported developer is transported to the first developer transport. The developer delivered from the other longitudinal end of the member to the other longitudinal end of the second developer transport member, and the developer delivered to the second developer transport member is transported to the second developer transport. The developer is conveyed in the first direction by the member, the developer is circulated and conveyed, and the developer conveyed in the second direction by the first developer conveying member is supplied to the developer carrier, The supplied developer is carried on the developer carrying member and conveyed to a development area between the developer carrying member and the image carrying member, and the conveyed developer is capable of transferring the electrostatic latent image. Additives in the developer used for visualization and conveyed by the second developer conveying member In the image forming apparatus added toner is replenished,
A cleaning device that removes transfer residual toner adhering to the intermediate transfer member, and the cleaning device includes a brush roller that rotates while the brush is in contact with the surface of the intermediate transfer member to clean the intermediate transfer member; And a portion on one end side in the longitudinal direction of the brush roller corresponding to one end side of the first developer transport member and the second developer transport member has higher cleaning ability than other brush roller portions. An image forming apparatus comprising the brush roller. A charging device; an image carrier charged by the charging device; an exposure device that exposes the charged image carrier to form an electrostatic latent image on the image carrier; and And a transfer belt that carries and conveys a transfer material onto which the toner image on the image carrier is transferred, and the developing device includes a toner to which an additive has been added. A developer carrying member carrying and carrying a developer having a carrier; a first developer carrying member disposed substantially parallel to the developer carrying member and driven to rotate; and the first development. A second developer conveying member that is arranged substantially parallel to the agent conveying member and is driven to rotate. The developer conveyed in the first direction by the second developer conveying member is From one longitudinal end of the second developer conveying member to one longitudinal end of the first developer conveying member The developer transferred to the first developer conveying member is conveyed in the second direction opposite to the first direction by the first developer conveying member, and is conveyed. The developer is transferred from the other end in the longitudinal direction of the first developer transport member to the other end in the longitudinal direction of the second developer transport member, and is transferred to the second developer transport member. The developer is conveyed in the first direction by the second developer conveying member, the developer is circulated and conveyed, and the developer is conveyed in the second direction by the first developer conveying member. Is supplied to the developer carrier, and the supplied developer is carried on the developer carrier and conveyed to a development region between the developer carrier and the image carrier. The developer is used for visualizing the electrostatic latent image and is conveyed by the second developer conveying member. During developer, an image forming apparatus to which the toner which additives have been added is supplied,
A cleaning device that removes toner adhering to the transfer belt, the cleaning device including a brush roller that rotates while the brush is in contact with the surface of the transfer belt to clean the transfer belt; The brush roller is configured such that the portion of the brush roller in the longitudinal direction corresponding to one end of the developer transport member and the second developer transport member has higher cleaning ability than the other brush roller portions. An image forming apparatus. 3. The image forming apparatus according to claim 1, wherein the bending rigidity of the brush fibers of the brush roller portion having the high cleaning ability is set higher than the bending rigidity of the brush fibers of the brush roller portion having the low cleaning ability. The image forming apparatus according to claim 1, wherein an outer diameter of the brush roller portion having a high cleaning ability is set smaller than an outer diameter of the brush roller portion having a low cleaning ability.

Images