JP4955991B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to image forming apparatuses such as analog and digital copying machines, laser beam printers, facsimiles, etc., regardless of whether they are monochrome or color. In particular, the present invention relates to a cleaning brush for cleaning means for removing toner, paper dust and the like adhering to an image carrier and an image forming apparatus including the same.

  2. Description of the Related Art Conventionally, there is known a method in which a cleaning brush is brought into contact with an upstream side in the image carrier moving direction of a cleaning blade tip contact position to convey transfer residual toner (see Patent Document 1).

In addition, a method is known in which the image carrier is uniformly worn and foreign matters on the image carrier are removed (see Patent Document 2).
JP 58-144875 A Utility Model Registration No.2520078

  However, even if the cleaning brush is pressed against the image carrier in the above-described configuration, discharge products generated from the charger or the like adhere to the image carrier if the rubbing force is not sufficient. For this reason, image defects such as “image flow” in which an image flows when used for the first time in the morning and “toner filming” in which toner or a component in the toner adheres to the image carrier occur. In addition, as the durability progresses, the unevenness of wear generated on the surface of the image bearing member, streaks, scratches, and other discharge products deposited on the grooves, toner, or components in the toner adhere to the image carrier, causing image defects. .

Further, in recent years, an image bearing member (universal hardness value (HU) of 150 N / mm ² or more) which has a hard surface and aims for a long life has been used in an image forming apparatus. For this reason, the frictional force between the image carrier and the cleaning blade is high from the initial state of the image carrier, and the frictional force between the image carrier and the cleaning blade increases as the durability progresses. For this reason, blade defects, chipping, chattering, etc., and other image defects such as toner slipping through the nip of the cleaning blade occur.

  Therefore, as a means for reducing the frictional force between the cleaning blade and the image carrier while maintaining the long life of the image carrier, a large number of streaks are inserted in the circumferential direction of the image carrier to roughen the surface of the image carrier. There is a method of applying surface treatment. In this case as well, discharge products generated from a charger or the like, or deposits such as toner or components in the toner accumulate on the grooves formed by roughening, and streak-like image defects that fit in the grooves Will occur.

  Further, when a roughened image carrier is used, the time until this image defect occurs is much faster than an image carrier that is not roughened.

  The present invention has been made in view of the above problems, such as uneven wear, streaks, scratches, etc. on the image carrier caused by durability, and a roughened image carrier aiming at long life and high image quality. The object is to prevent the occurrence of “image flow” and “toner filling” due to streaks.

A photosensitive drum on which an electrostatic latent image is formed, a blade member that comes into contact with the surface of the photosensitive drum to clean the surface, and is rotatable, contacts the surface of the photosensitive drum, and rubs the surface. An image forming apparatus having a cleaning brush for cleaning,
The photosensitive drum is roughened to have a surface roughness of 0.3 μm or more, and the cleaning brush is formed in a spiral shape with respect to the rotation axis of the cleaning brush, and has a plurality of types with different widths in the rotation axis direction. The plurality of types of hairs are characterized in that the narrow hairs in the direction of the rotation axis are longer than the wide hairs.

  According to the present invention, “image flow caused by wear unevenness, streaks, scratches, etc. on the image carrier caused by durability and streaks of the image carrier etc. roughened for long life and high image quality. And “toner filling” can be prevented.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
1 is a cross-sectional view of an image forming apparatus according to the present invention, FIG. 2 is a schematic cross-sectional view of a cleaning device of the image forming apparatus, FIG. 3 is a partial perspective view of a cleaning brush of the cleaning apparatus, and FIG. It is a cross-sectional view.

  An image reading mechanism for reading image information of a document 30 as an information providing source is arranged on the upper part of the main body of the image forming apparatus shown in FIG.

  That is, the reflected light of the light source 31 that irradiates the original 30 placed on the platen glass (not shown) with the image surface facing downward is reflected by the mirrors 5a, 5b, 5c, and then the image reading element and the control The digital image signal is image-modulated through the CPU.

  Next, the digital image signal is irradiated as a laser beam 35 onto a charged portion on the outer peripheral surface of the image carrier 1, and an electrostatic latent image is formed on the charged portion.

  The image bearing member 1 has an electrostatic latent image formed on the charged portion of the outer peripheral surface by being irradiated with laser light 35 after the outer peripheral surface is uniformly charged by the primary charger 3 disposed above the image carrier 1. The electrostatic latent image is developed as a toner image with toner that is a developer of the developing device 4.

  Next, after the toner image formed on the outer peripheral surface of the image carrier 1 is transferred to the recording medium P by the transfer charger 7, the recording medium P is separated from the outer peripheral surface of the image carrier 1. The recording medium P separated from the outer peripheral surface is conveyed to the fixing device 9 by the conveying belt 45. The recording medium P conveyed to the fixing device 9 is subjected to a fixing process by supplying heat from the fixing device 9 and applying pressure, and then discharged onto the paper discharge tray 46.

  Note that the outer peripheral surface of the image carrier 1 after the transfer process is cleaned by a cleaning device 8 such as removal of residues, and then prepared for the next electrostatic latent image formation.

  On the other hand, a recording medium P made of paper, synthetic resin, or the like (hereinafter, the case where the recording medium P is made of paper will be described in the present embodiment) is conveyed as follows. That is, after the sheet 41 is selectively fed from the cassettes 41 and 41 detachably disposed at the lower part of the main body of the image forming apparatus by the sheet feed roller pair 42 and 42, it is downstream from the sheet feed roller pair 42 and 42 in the recording medium conveyance direction. It is conveyed to the registration roller pair 43 arranged on the side.

  The recording medium P conveyed to the registration roller pair 43 is conveyed to a transfer space formed between the image carrier 1 and the transfer charger 7 in synchronization with the rotation of the image carrier 1, and is subjected to a transfer process and a fixing process. Is applied to the paper discharge tray 46.

  Next, the cleaning device 8 will be described with reference to FIG.

  The cleaning device 8 is disposed adjacent to the image carrier 1 that is rotationally driven in the direction indicated by the arrow X (clockwise). The cleaning device 8 includes toner and talc remaining on the surface of the image carrier 1 in sliding contact with the surface of the image carrier 1 while rotating in the direction indicated by the arrow Y (counterclockwise) at a peripheral speed ratio of 110%. And a cleaning brush 20 for removing foreign substances such as.

  A scraper 21 is provided for contacting the tip of the cleaning brush 20 and scraping off toner adhering to the cleaning brush 20. A cleaning blade 22 is provided for rubbing the surface of the image carrier 1 to remove foreign matters such as toner and talc remaining on the surface of the image carrier 1. In addition, a toner conveying screw 23 and the like are provided for conveying and collecting the toner removed from the surface of the image carrier 1 by the cleaning brush 20 and the cleaning blade 22 to a waste toner storage unit (not shown).

  The image carrier 1 is composed of a photosensitive drum having an outer diameter of φ84 mm. In general, as shown in FIG. 4, the photosensitive drum 1 has a photosensitive layer coated on an aluminum cylinder 1a, and the photosensitive layer has a two-layer structure including a charge generation layer 1b and a charge transport layer 1c thereon. Is formed. In the photosensitive drum 1 according to the present embodiment, a surface release layer 1d is further formed on the charge transport layer 1c. In the outermost surface layer of these photosensitive drums 1, fluororesin particles are usually dispersed for the purpose of reducing the frictional force against the cleaning blade 22.

  In the case of the photosensitive drum 1 aiming at long life and high image quality, the content of the fluororesin particles may be reduced. By reducing the content of the fluororesin particles, the hardness of the photosensitive drum 1 is increased and a long life and high image quality can be achieved, but the frictional force between the photosensitive drum 1 and the cleaning blade 22 is increased.

Therefore, when the photosensitive drum 1 is tested using a Vickers square pyramid diamond indenter and the universal hardness value (HU) of the photosensitive drum 1 when pressed with a load of 6 mN is 150 N / mm ² or more, the photosensitive drum 1 and the cleaning are performed. In order to suppress an increase in frictional force with the blade 22, a large number of streaks are provided in accordance with the circumferential direction of the surface of the photosensitive drum 1. That is, the surface of the photosensitive drum 1 was intentionally roughened, and the surface roughness Rz was set to 0.3 μm or more. FIG. 5 shows the surface profile of the photosensitive drum 1 at this time.

  Here, the universal hardness value (HU) is a square pyramid diamond indenter, and the load when a depression is made on the test surface is obtained from the diagonal length of the permanent depression remaining after the load is removed. It is the value divided by the surface area of the depression. In the present invention, a Vickers indenter was attached to a Fisherscope (R) H100V manufactured by Fischer, and measurement was performed in an environment of 25 ° C. and a humidity of 50% to obtain a value.

  The surface roughness of the photosensitive drum is measured using a surface roughness measuring machine SE3500 manufactured by Kosaka Laboratory under the conditions of Cutoff 0.8 mm, measuring length 2.5 mm, and measuring speed 0.1 mm / s. did.

In this embodiment, an organic photoreceptor is used as the photosensitive drum 1, but an inorganic photoreceptor such as a-Si can also be used as long as the universal hardness value (HU) is 150 N / mm ² or more. .

  Next, the cleaning brush 20 will be described with reference to FIG.

  As shown in FIG. 6, the cleaning brush 20 has a rotary shaft 20b, a cleaning brush hair 24, and an adhesive in which the cleaning brush hair 24 is planted on the base cloth 20c and the rotary shaft 20b and the base cloth 20c are bonded. It is comprised with the agent layer 20d. In the present embodiment, the cleaning brush hair body 24 having a density of 50 kF and a straight hair at the tip is used.

  Next, the cleaning brush 20 according to the present invention will be described with reference to FIGS.

  In the present embodiment, the thickness of the thick hair 24a shown in FIG. 3 is 6D (denier), and the thickness of the thin hair 24b is 3D.

  Examples of the material of the hair 24 of the cleaning brush 20 include conductive materials such as stainless steel and conductive rayon. In this embodiment, nylon is used. The single yarn diameter at this time is calculated to be about 30 μm for 6D and about 20 μm for 3D, respectively. Regarding the thickness of the thin hair body 24b, the thinner the hair, the more effective it is to achieve the object of the present invention.

Here, the ease of deformation of the hair body of the present invention is shown as a value (referred to as “deformation resistivity ρ”) obtained by multiplying the apparent Young's modulus of the hair body by the cross-sectional area (thickness) of the hair body. The hair body of the present invention satisfies the relationship of apparent Young's modulus Y (cN / dtex) of the hair body × thickness of hair body d (dtex) /100≧1.15N. However, the following relationship is satisfied. One denier (D) is the thickness of a yarn having a length of 9000 m and a weight of 1 g. Here, 1 denier is substantially equal to 1 decitex (dtex), and in the present invention, 1 denier = 1 decitex (dtex). In addition, although it is the thickness of a hair body, as a whole brush roller, although thickness does not change, it is an average value when ten pieces are extracted arbitrarily.

  However, the thinner, the lower the deformation resistivity ρ of the hair body 24 of the cleaning brush 20, and the lower the frictional force on the photosensitive drum 1. When the material of the hair body 24 of the cleaning brush 20 is nylon, the relationship between the deformation resistivity ρ and the thickness of the hair body 24 is 60 cN in 3D and 120 cN in 6D.

  Here, for the purpose of effectively removing the adhering matter by increasing the rubbing force of the cleaning brush on the image bearing member, the thickness of the hair of the cleaning brush was set to 6D (denier) or more for durability. . The material of the hair at this time is nylon, and its deformation resistivity ρ is about 1.15N.

  However, as the durability progressed, streaky image defects gradually occurred. This is because, when a cleaning brush composed of a hair having a thickness of 6D or more is used, the cleaning brush rubs the entire surface of the image carrier and discharge products generated from a charger or the like, toner or toner Remove deposits such as components.

  However, since the hair is thick, the tip of the hair of the cleaning brush does not enter a groove formed by uneven wear, streaks, scratches, etc. generated on the surface of the image carrier due to durability. For this reason, discharge products generated from chargers, etc., and deposits such as toner or components in the toner accumulate in this groove, and an image such as a streaky image flow or toner filming that fits in this groove. A defect occurred.

  On the other hand, when a cleaning brush composed of a thin hair having a thickness of 3D or less is used, the deformation resistivity ρ of the hair decreases as the thickness of the hair decreases, and the image carrier Sufficient rubbing force is not obtained. The material of the hair at this time was nylon, and the deformation resistivity ρ was about 60 cN. For this reason, as the durability progressed, image defects such as image flow and toner filming occurred on the entire surface of the obtained image.

  Therefore, as a single cleaning brush, a nylon hair body having a thickness of 6D and a nylon body having a thickness of 3D having the same length and the same deformation resistivity ρ are spirally wound around the rotation axis. I used the following. In this case, the hair end of the hair having a thickness of 3D or less does not enter the groove formed by durability, and the discharge product accumulated in the groove or the adhering matter such as the toner or the component in the toner cannot be removed. . For this reason, image defects such as streak-like image flow and toner filming that fit into the grooves occurred.

  This is because the lengths of the two types of hairs are the same, so that the hair with a thickness of 6D interferes with the intrusion into the groove of the hair with a thickness of 3D. For this reason, the effect that it is possible to remove the discharge product or the like deposited on the discharge generation groove of the thin hair body having a thickness of 3D and the adhering matter such as the toner or the component in the toner cannot be obtained.

  Here, the relationship between the configuration of the cleaning brush and the image flow is shown in Table 1.

From the results shown in Table 1, in order to obtain a sufficient rubbing force to the photosensitive drum 1, the deformation resistivity ρ of the hair 24 of the cleaning brush 20 must be 1.15 N or more.

  Therefore, to set the deformation resistivity ρ of the thin hair body 24b to 1.15N, the material of the hair body 24b is apparently changed to a material having a high Young's modulus, or the carbon content contained in the hair body 24b. And by changing the way of distribution.

  The two types of hairs 24a and 24b having different thicknesses are each formed in a spiral shape with respect to the rotating shaft 20b.

  Further, with respect to the thickness of the hair body 24 of the cleaning brush 20, as shown in FIG. 7A, a predetermined effect can be obtained by changing the thickness of the hair body 24 as a whole. However, the thin bristle body 24b may be broken by a scraper or the like that is in contact with the cleaning brush 20, and may not have durability.

  Therefore, the hairs 24a and 24b as shown in FIG. 7B, in which only the portion in contact with the photosensitive drum 1 is composed of two different thicknesses, are more preferable. Even in this case, it is desirable that the deformation resistivity ρ of the portion of the hair body 24 in contact with the photosensitive drum 1 is 1.15 N or more for all the hair bodies 24 of one cleaning brush 20.

  Next, Table 2 shows the results of studies using the roughened photosensitive drum 1 having the profile shown in FIG. This also assumes a streak or the like on the photosensitive drum 1 caused by durability. This examination was performed with the cleaning brush 20 having only the hair body 24a of which the material is nylon and the thickness is 6D. Further, in the case of the cleaning brush 20 having only the 3D hair body 24b and the cleaning brush 20 formed by mixing and winding the 3D hair body 24b and the 6D hair body 24a. I went. The hairs 24 (24a, 24b) of these cleaning brushes 20 are made of the same material and have the same density.

  In addition to the above brushes, the following three types of cleaning brushes were prepared with respect to the cleaning brush 20 constituted by mixing and winding the 3D hair body 24b and the 6D hair body 24a.

  A cleaning brush having the same length of 5 mm, in which the deformation resistivity ρ of the 3D and 6D hairs 24a and 24b are all 1.15N or more. Further, the deformation resistivity ρ of the 3D and 6D hair bodies 24a and 24b are all 1.15N or more, and the 3D hair body (7 mm length) is 6D hair body (the length is The cleaning brush is longer than 5 mm.

  As a method of changing the thickness by changing the deformation resistivity ρ of the hair body 24 to 1.15 N or more, the material of the hair body 24 is changed, or the content or dispersion of carbon contained in the hair body 24 There is a way to change the way of the.

  These cleaning brushes 20 were each mounted on a cleaner of an idling rotary machine at a setting of 0.7 mm intrusion with respect to the photosensitive drum 1, and were idly rotated for 5 hours and 10 hours, respectively. As the idle rotating machine, a corona charger was used for both primary charging and transfer. After idling 5 hours and 10 hours later, the image was imaged after being left overnight, and the image defect level was judged.

As shown in Table 2, when the thickness of the hair 24 of the cleaning brush 20 is 3D, the rubbing force to the photosensitive drum 1 is not obtained, and the discharge products attached on the surface of the photosensitive drum 1 are removed. As a result, the image after leaving overnight was defective on the entire surface. This phenomenon becomes conspicuous because the deformation resistivity ρ decreases as the thickness of the hair 24 of the cleaning brush 20 decreases, and the rubbing force of the photosensitive drum 1 decreases. Further, when the thickness of the hair 24 of the cleaning brush 20 is 6D, the rubbing force to the photosensitive drum 1 is large.

  However, the hair 24 did not enter the groove on the photosensitive drum 1 as shown in FIG. 4, and the discharge product accumulated only in the groove, and the image after standing overnight became streaky. This phenomenon becomes more prominent as the thickness of the hair 24 of the cleaning brush 20 is increased.

  Finally, a case where hairs 24 having different thicknesses are spirally wound around one cleaning brush 20 will be described.

  In the case of the cleaning brush having the same material thickness of 6D and the same length of 3D hair, the 6D-thick hair 24a rubs the entire photosensitive drum 1 and discharges attached to the photosensitive drum 1. Most of the product is removed. Further, the hair tips of the 3D-thick hairs 24b enter into the grooves that are not contained in the hair tips of the 6D-thick hairs 24a, and discharge products and the like accumulated in the grooves are removed. As a result, a slightly streak-like image was obtained from the image that was left overnight after being idled for 5 hours without causing any image flow on the entire surface.

  In the case of the same material, the thin bristle body 24b has a low deformation resistivity ρ, so that a little rubbing force to the photosensitive drum 1 cannot be obtained, and the discharge products and the like are gradually on the surface of the photosensitive drum 1. This is because it accumulates in the groove. For this reason, as shown in Table 2, the image after 5 hours idling was slightly streaked, and the image after 10 hr idling was clearly defective in stripes. The thinner the hair 24 is, the more prominent the phenomenon is.

  Further, when only a thin hair having a high deformation resistivity ρ and a high rubbing force is used, the area where the hair hits the photosensitive drum is small, resulting in unevenness and scratches. In order to prevent this, when the contact area is increased by increasing the density of the hair of the brush, clogging due to residual toner between the fibers occurs, and the cleaning function is not provided.

  On the other hand, in the case of cleaning brushes having the same deformation resistance ρ of 1.15N or more and the same length, cleaning composed of 3D and 6D hair bodies 24 (24a, 24b) having a deformation resistance ρ of 1.15N or more. In the brush 20, the thin hair body 24 b has the same deformation resistance ρ as the thick hair body 24 a. A sufficient rubbing force can be obtained to refresh the surface of the photosensitive drum 1, but since the two types of hairs have the same length, the hair having a thickness of 6D is inserted into the groove of the hair having a thickness of 3D. The intrusion is obstructed, and the thin hair does not penetrate into the back of the groove. For this reason, the tip of the hair having a thickness of 3D or less does not enter into the groove formed by durability, and discharge products accumulated in the groove and adhered matter such as toner or components in the toner can be removed. In other words, image defects such as streak-like image flow and toner filming that fit into the grooves occurred.

  Further, in the case of a cleaning brush in which the deformation resistivity ρ is all 1.15 N or more and the hair having a thickness of 3D is longer than the hair having a thickness of 6D, the following results were obtained. That is, the thin hair body 24b has the same deformation resistance ρ as that of the thick hair body 24a, and a sufficient rubbing force is obtained to refresh the surface of the photosensitive drum 1, and the 3D thickness hair is 6D. Since it is longer than the hair body, it becomes easy to enter the groove of the hair body having a thickness of 3D. That is, since the 3D-thick hair body penetrates to the back of the groove, the image after performing the idle rotation for 10 hours did not generate an image flow on the entire surface, and an image that was not streak-like was obtained. .

  In the above description, the cleaning brush composed of two different thicknesses has been described. However, the same effect as described above can be obtained with two or more cleaning brushes. The same applies to the case where at least two types of different cleaning brush hairs are implanted in different cleaning brushes.

<Embodiment 2>
Next, a second embodiment of the present invention will be described. The second embodiment is the same as the first embodiment unless otherwise specified, and the same components are denoted by the same reference numerals and the description thereof is omitted.

  In the present embodiment, the material of the hair of the cleaning brush, the carbon content and the manner of dispersion are not changed, and the deformation resistivity ρ of both the thin hair and the thick hair is 1.15 N or more. This will be described with reference to FIG.

  The basic configuration of the apparatus and the cleaning brush 20 used in the present embodiment is the same as that shown in the first embodiment.

  FIG. 8A shows the hair of the cleaning brush used in this embodiment. This hair body is a flat hair body having a wide surface A and a narrow surface B and a deformation resistivity ρ of 1.15 N or more. Further, the width of the hair on the A side is 30 μm or more, the width of the hair on the B side is 20 μm or less, and the thickness of the hair in the first embodiment is equivalent to 6D or more on the A side and 3D or less on the B side. To do. As shown in FIG. 8B, these hairs were planted on the base cloth 20c, and the same effect as in the first embodiment was obtained by winding the hairs around the rotating shaft 20b in a spiral shape.

  FIG. 8A shows the hair of the cleaning brush used in this embodiment. This hair body is a flat hair body having a wide surface A and a narrow surface B and a deformation resistivity ρ of 1.15 N or more. Further, the width of the hair on the A side is 20 μm or less, the width of the hair on the B side is 30 μm or more, and the thickness of the hair in the first embodiment corresponds to 3D or less on the A side and 6D or more on the B side. To do. As shown in FIG. 8B, these hairs were planted on the base cloth 20c, and the same effect as in the first embodiment was obtained by winding the hairs around the rotating shaft 20b in a spiral shape.

  This has a function equivalent to that of the thick hair body of the first embodiment by matching the wide side A of the hair body with the rotation direction of the cleaning brush 20. This is because by aligning the narrow side B of the hair body with the rotation direction of the cleaning brush 20, it has a function equivalent to that of the thin hair body of the first embodiment.

  In the present embodiment, the narrow hair body is longer than the wide hair body with respect to the rotation direction.

  For this reason, the hair body 25a removes discharge products and the like on the entire surface of the photosensitive drum 1, and the hair body 25b removes discharge products and the like that the hair ends enter into the grooves on the surface of the photosensitive drum 1 and accumulates in the grooves. To do.

  In addition, it is not necessary to separately prepare hairs having different thicknesses, and thus the cost can be reduced.

  In FIG. 8, the number of hair bodies 25 of the cleaning brush is described in a relatively small number, but this is for the purpose of explanation, and actually, the hair body 25 is composed of a large number of hair bodies 25.

  In the present embodiment, the cleaning brush 20 composed of two different shapes has been described. However, at least two types of different cleaning brush hairs are implanted in different cleaning brushes. Even if it is, the same effect as described above can be obtained.

<Embodiment 3>
Next, a third embodiment of the present invention will be described. The third embodiment is the same as the first embodiment unless otherwise specified, and the same components are denoted by the same reference numerals and the description thereof is omitted.

  In the present embodiment, the tip of the hair of the cleaning brush 20 has a loop shape, and the shaft side of the loop faces the rotation direction of the cleaning brush 20 at the portion in contact with the photosensitive drum. (Here, the axis side of the loop refers to the side where the troublesome side and the back side where the hair is folded back when the hair forming the loop is viewed. On the other hand, the hair loops. The side on which the surface to be formed can be seen is called the loop surface side.) In other words, the base formed so that the surface formed by the looping of the hair body 26 is substantially parallel to the rotation direction of the cleaning brush 20. The cloth 20c is flocked.

  Further, in the present embodiment, the deformation of the portion of the hair that is composed of two or more different hair thicknesses and that is in contact with the photosensitive drum 1 of the hair comprised in the single cleaning brush 20. A case where the resistivity ρ is all 1.15 N or more will be described with reference to FIG.

  The basic configuration of the apparatus and the cleaning brush 20 used in the present embodiment is the same as that shown in the first embodiment.

  FIG. 9A shows the hair of the cleaning brush used in the present embodiment.

  The hair body 26 has a loop-shaped tip, and its deformation resistivity ρ is 1.15 N or more. As shown in FIG. 9B, the hair body 26 is planted on the base cloth 20 c so that the axial side of the loop at the front end of the hair body faces the rotation direction of the cleaning brush 20. (The surface formed by looping the hair body 26 is implanted in the base fabric 20c so that the surface formed by the hair brush 26 is substantially parallel to the rotation direction of the cleaning brush 20.) By doing so, the rotation shaft 20b is spirally formed. By winding, the same effect as in the first embodiment was obtained.

  This is because the axis side of the loop faces the rotation direction of the cleaning brush 20, and the same idea as when the tip of the hair body 26 is straight hair can be obtained.

  In this Embodiment, the hair formed so that the loop formed by the thin hair body may become longer than the loop formed in the thick hair body. That is, the length in the radial direction of the cleaning brush 20 is longer in the thin hair body than in the thick hair body.

  In this embodiment, the cleaning brush composed of two different thicknesses has been described. However, the same effect as described above can be obtained with two or more types. The same applies to the case where at least two types of different cleaning brush hairs are implanted in different cleaning brushes.

<Embodiment 4>
Next, a fourth embodiment of the present invention will be described.

  In the present embodiment, the tip of the hair is in a loop shape, and the shaft side and the surface side of the loop are configured to face the rotation direction of the cleaning brush, respectively, at the portion in contact with the photosensitive drum. The cleaning brush will be described with reference to FIG.

  The basic configuration of the apparatus and the cleaning brush 20 used in the present embodiment is the same as that shown in the first embodiment.

  FIG. 10A shows the hair of the cleaning brush used in the present embodiment.

  The hair body 27 has a looped tip, and its deformation resistivity ρ is 1.15 N or more. As shown in FIG. 10B, the hair 27 is implanted in the base cloth 20c so that the shaft side and the surface side of the loop at the tip of the hair body face the rotation direction of the cleaning brush 20, respectively. 20 b is spirally wound (the hair body 26 is implanted so that the surface formed by looping is parallel and perpendicular to the rotation direction). By doing so, the same effect as in the first embodiment was obtained.

  This is because the hair body 27b in which the axis side of the loop faces the rotation direction of the cleaning brush 20 (the surface formed by looping is planted in parallel with the rotation direction) is the first embodiment. Has the function of a thin hair body. Further, the bristle body 27b in which the surface side of the loop faces the rotation direction of the cleaning brush 20 (the surface formed by looping is planted perpendicularly to the rotation direction) is thick in the first embodiment. This is because it has the function of a hair body.

  In the present embodiment, as shown in FIG. 10B, the surface formed by the loop of the hair body 27 is perpendicular to the surface of the brush that is parallel to the rotation direction of the cleaning brush 20. It is planted so that the length is long.

  For this reason, the hair 27a removes the discharge products and the like on the entire surface of the photosensitive drum 1, and the hair 27b removes the discharge products and the like that the hair ends enter the grooves on the surface of the photosensitive drum 1 and accumulates in the grooves. To do.

  In the present embodiment, the cleaning brush constituted of two different types of loop directions has been described, but the same effect as described above can be obtained with two or more types. The same applies to the case where at least two types of different cleaning brush hairs are implanted in different cleaning brushes.

  In the above-described embodiment, the case where the cleaning brush is applied to the image forming apparatus has been described as an example. However, the present invention is not limited thereto as long as it is within the scope of the technical idea of the present invention. For example, the present invention can also be applied to a detachable process unit having an image carrier and a cleaning device having at least a cleaning brush.

1 is a cross-sectional view of an image forming apparatus according to the present invention. FIG. 3 is a cross-sectional view of a cleaning device of the image forming apparatus according to the present invention. FIG. 3 is a partial perspective view of a cleaning brush constituting the cleaning device of the image forming apparatus according to the present invention. It is a cross-sectional view of a photosensitive drum. It is a figure which shows the surface profile of a photosensitive drum. It is sectional drawing of the cleaning brush which concerns on this invention. It is the schematic of the cleaning brush which concerns on Embodiment 1 of this invention. It is the schematic of the cleaning brush which concerns on Embodiment 2 of this invention. It is the schematic of the cleaning brush which concerns on Embodiment 3 of this invention. It is the schematic of the cleaning brush which concerns on Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image carrier 1a Aluminum cylinder 1b Charge generation layer 1c Charge transport layer 1d Surface release layer 3 Primary charger 4 Developing device 5a-5c Mirror 7 Transfer charger 8 Cleaning means 9 Fixing device 20 Cleaning brush 20b Rotating shaft 20c Base cloth 20d Adhesive Layer 21 Scraper 22 Cleaning Blade 23 Toner Conveying Screw 24 Hair 24a Thick Hair 24b Thin Hair 25 Flat Hair 25a Wide Hair 25b Small Hair 26 Hair with a loop at the tip 26a Thick hair 26b Thin with a hair 27 Hair with a loop at the tip 27a Hair with the loop side facing the rotation direction of the cleaning brush 27b The shaft side of the loop is the rotation of the cleaning brush Oriented hair 30 Image reading mechanism 31 Light source 35 Laser light 41 cassette 42 sheet feeding roller pair 43 registration roller pair 45 transport belt 46 discharge tray

Claims (4)

A photosensitive drum on which an electrostatic latent image is formed, a blade member that comes into contact with the surface of the photosensitive drum to clean the surface, and is rotatable, contacts the surface of the photosensitive drum, and rubs the surface. An image forming apparatus having a cleaning brush for cleaning,
The photosensitive drum is roughened to have a surface roughness of 0.3 μm or more, and the cleaning brush is formed in a spiral shape with respect to the rotation axis of the cleaning brush, and has a plurality of types with different widths in the rotation axis direction. preparedness hair body, said plurality of kinds of hair body, an image forming apparatus, wherein a narrow bristle body width of the rotation axis direction is longer than wide bristle body width. The narrow Iketai the width is not less 3D less thickness, wide Iketai of the width of the image forming apparatus according to claim 1, characterized in that it is 6D or more thickness. When the apparent Young's modulus of the plurality of types of hair is Y (cN / dtex) and the thickness is d (dtex), the plurality of types of hair is Y × d / 100 ≧ 1.15 (N). The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 1, wherein at least one of the plurality of types of hair is a loop-shaped hair.