JP2006201591A - Process unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein developer adhering to an image carrier in a non-printing area is increased as a process unit is long-lived and adheres to an electrifying means, a transfer means and a developing means, consequently, a process unit and an image forming apparatus are remarkably contaminated inside, thereby bringing the deterioration of printing quality. <P>SOLUTION: The process unit has the image carrier and the developing means arranged to be opposed to the image carrier and supplying the developer to the image carrier so as to develop an image to be visible image, sealing members respectively positioned near both ends of the developing means and coming into contact with the surface of the developing means, so as to prevent the leakage of the developer, and a cleaning means coming into contact with the surface of the image carrier, so as to remove the developer on the image carrier. The cleaning means comes into contact with the area of the image carrier opposed to the surface of the developing means at least coming into contact with the sealing members. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a process unit that develops and visualizes an electrostatic latent image formed on a latent image carrier used in a copying apparatus, printer, facsimile, or the like, which is an image forming apparatus, and an image forming apparatus using the process unit. is there.

  An example of a conventional process unit 17 using an electrophotographic system is shown in FIG. In FIG. 9, the charging roller 4 rotating in the direction of arrow H uniformly charges the surface of the photosensitive drum 1 rotating in the direction of arrow D. The LED head 20 attached to the image forming apparatus selectively irradiates light onto the photosensitive drum 1 whose surface is uniformly charged to form an electrostatic latent image. The developing roller 2 rotating in the direction of arrow E is attached with toner by the toner supply roller 3 rotating in the direction of arrow F, and the toner blade 10 thins the toner layer on the developing roller 2. The electrostatic latent image on the photosensitive drum 1 is developed with toner by the developing roller 2, and the developed toner forms a toner image on the photosensitive drum 1. Thereafter, the toner image on the photosensitive drum 1 is transferred to the printing medium 11 by the transfer roller 5 rotating in the direction of arrow G. On the photosensitive drum 1 after the transfer, toner remaining on the surface of the photosensitive drum 1 without being transferred in the printing region (hereinafter abbreviated as “transfer residual toner”) remains. Cleaning is performed from above the photosensitive drum 1 by using a cleaning roller 19 that rotates at a high speed.

10 is a cross-sectional view taken along the line CC ′ in FIG. In order to prevent the toner from leaking out of the process unit 17 from the vicinity of both ends of the developing roller 2 or from both ends of the toner supply roller 3, a seal member 21 having a certain width such as felt is provided in the vicinity of both ends of the developing roller 2. Is sealed by. In FIG. 10, the cleaning roller 19 width W19, the width between the sealing members 21a and 21b in contact with the vicinity of both ends of the developing roller (= toner supply roller width) W3, and the developing roller 2 width W2 are used. Of the print media, the maximum paper width W11 is the maximum paper width, and the maximum image region width is W30 of the maximum print paper among the used print media. The cleaning roller 19 width W19 is set to be on the maximum image area W30 as shown in FIG.
JP 2000-89637 A

  When the maximum image area width W30 of the paper, which is the maximum width among the print media used, is set as the print area, and the area outside the print area on the photosensitive drum 1 and in contact with the developing roller 2 is set as the non-print area, non-printing is performed. In the region, the toner adheres due to the fog toner due to the reversely charged toner, the background dirty toner due to overcharging, or the toner adhered due to the van der Waals force. Even if the toner that was not cleaned with the non-cleaning width W31 included in the non-printing area remained on the drum, the remaining amount was very small. However, the amount of toner adhering to the photosensitive drum 1 in the non-printing area increases as the life of the process unit increases. As a result, the toner adhering to the photosensitive drum 1 often adheres to the charging roller 4 and the transfer roller 5 in the process unit or returns to the developing roller 2, which causes toner contamination in the process unit and the image forming apparatus. It becomes noticeable and print quality deteriorates.

  The present invention adopts the following configuration in order to solve the above problems. That is, an image carrier and an image carrier that are disposed to face each other, a developer that supplies a developer to the image carrier and visualizes the image carrier, and is positioned in the vicinity of both ends of the developer. In a process unit having a seal member that contacts the surface of the developing unit and prevents leakage of the developer, and a cleaning unit that contacts the surface of the carrier and removes the developer on the image carrier, the cleaning unit includes at least the cleaning unit The process unit is a cleaning unit that is in contact with a region of the image carrier that faces the surface of the developing unit that is in contact with a seal member.

  According to the present invention having the above-described configuration, with respect to the toner remaining on the photosensitive drum 1 after the transfer, the adhered toner in the non-printing area, in particular, the portion where the developing roller and the seal member are in contact with the transfer residual toner in the printing area. By providing a means for cleaning the damaged toner, it is possible to solve the problem of deterioration in print quality.

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

  In the process unit of Example 1, with respect to the toner remaining on the photosensitive drum 1 after the transfer, a means for cleaning the adhering toner in the non-printing area as well as the transfer residual toner in the printing area is provided.

(Constitution)
As shown in FIG. 1, the image forming apparatus 40 includes a paper cassette 41 that stores a print medium 11 such as paper, and a hopping roller 42 that separates and conveys the print medium 11 one by one. Pinch rollers 44, 45, a registration roller 46, and a conveyance roller 47 are provided on the downstream side of the hopping roller 42 in the medium conveyance path 43.

  Further, the medium transport path 43 is provided with a process unit 15, an LED head 20, and a transfer roller 5 disposed to face the process unit 15.

  Furthermore, a fixing device 48 and discharge rollers 49, 50, 51, 52 for discharging the printing medium 11 that has passed through the fixing device 48 are provided on the downstream side of the process unit 15 and the transfer roller 5 on the medium conveyance path 43. It has been.

  2 and 3 show the configuration of the process unit 15 of the first embodiment. The process unit 15 includes a photosensitive drum 1 as an image carrier, a developing roller 2 as a developing unit, a toner 9 as a developer, a toner supply roller 3 that supplies toner to the developing roller 2, and a thin toner layer on the developing roller 2. The toner blade 10 to be formed, the charging roller 4 for charging the surface of the photosensitive drum 1, the toner cartridge 12 containing the toner 9, the seal member 21 for preventing toner leakage, the cleaning blades 22, 23 as cleaning means, and the cleaning blades 22, 23 A toner reservoir 26, a holder 27 for fixing the cleaning blade 22 to the frame of the process unit 15, and a holder 28 for fixing the cleaning blade 23 to the frame of the process unit 15. The cleaning blade 22 and the cleaning blade 23 are made of urethane elastomer as a rubber elastic body. When the photosensitive drum 1 and the charging roller 2 are opposed to each other in the rotation direction D of the photosensitive drum 1, the cleaning blade 22 is the cleaning blade. The cleaning blade 23 contacts the photosensitive drum 1 upstream of the cleaning blade 23 and downstream of the cleaning blade 22. The image forming apparatus includes an LED head 20 serving as an exposure device and a transfer roller 5 that transfers a toner image to the print medium 11. FIG. 4 is an enlarged view of the front end of the cleaning blade 22 according to the first embodiment. The cleaning blade 22 presses the edge portion of the cleaning blade 22 against the photosensitive drum 1, and cleans the toner remaining on the photosensitive drum 1 at the edge portion. As for the cleaning blade 23, the leading edge portion is pressed against the surface of the photosensitive drum 1 in the same manner as the cleaning blade 22.

  The cleaning blade 22 is made of a urethane elastomer having a rebound resilience of 60% at 25 ° C., and is in contact with the photosensitive drum 1 with a load of 3.5 g / mm. The rebound resilience at 25 ° C. of the urethane elastomer constituting the cleaning blade 22 is not limited to the above description, and may be 50% to 70%. The load with which the cleaning blade 22 contacts the photosensitive drum 1 is not limited to the above description, and may be 2 g / mm to 5 g / mm. On the other hand, the cleaning blade 23 is made of a urethane elastomer having a rebound resilience of 50% at 25 ° C., and is in contact with the photosensitive drum 1 with a load of 2 g / mm. The rebound resilience at 25 ° C. of the urethane elastomer constituting the cleaning blade 23 is not limited to the above description, and may be 40% to 60%. The load with which the cleaning blade 23 comes into contact with the photosensitive drum 1 is not limited to the above description, and may be 0.5 g / mm to 3.5 g / mm.

  It is preferable that the cleaning blade 22 that cleans the transfer residual toner in the printing region has a higher pressure contact with the photosensitive drum 1 or has a larger rebound resilience than the cleaning blade 23 that cleans the adhered toner in the non-printing region. Since the transfer residual toner in the printing region has an overwhelmingly larger amount of toner than the adhering toner in the non-printing region, the cleaning blade 22 has a relatively higher cleaning ability than the cleaning blade 23, that is, the pressure contact pressure. Larger or higher rebound resilience is preferred. On the other hand, since the cleaning blade 23 cleans the adhered toner area in the non-printing area where the amount of toner is small, there is little toner acting as a lubricant between the photosensitive drum and the cleaning blade during cleaning. For this reason, if the contact force is the same as that of the cleaning blade 22, the blade may turn over to the rotational direction side of the photosensitive drum or cause abnormal wear of the contact portion between the blade and the photosensitive drum. Therefore, it is preferable that the cleaning blade 23 has a relatively smaller pressure contact pressure or lower resilience than the cleaning blade 22.

  FIG. 5 is a cross-sectional view taken along the line AA ′ in FIG. FIG. 5 shows the photosensitive drum 1, the developing roller 2, the toner supply roller 3, the seal members 21a and 21b, the cleaning blade 22, the cleaning blades 23a and 23b, and their widths. The width of the cleaning blade 22 in contact with the photosensitive drum 1 is W22, the width of the cleaning blades 23a and 23b in contact with the photosensitive drum 1 is W23a and W23b, and at least one of the cleaning blade 22 and the cleaning blade 23 is cleaned. Let the region be WCL. The width between the seal members (= toner supply roller width) W3 sandwiched between the seal members 21a and 21b in contact with both ends of the surface of the developing roller 2 is W3, and the width of the developing roller 2 is W2. Of the printing media to be used, the maximum paper width is defined as the maximum paper width W11. Among the papers having the maximum width among the print media used, when the maximum image area width is W30, the relationship between the lengths is W3 ≧ W22 ≧ W30. The width W23 of the cleaning blade 23 will be described with reference to the left side of FIG. 5 and the width W23a. One end of the cleaning blade 23a is at the same position as or outside of the end E1 on the outer side of the seal member 21a. The other end of the cleaning blade 23a is inside the left end E2 of the cleaning blade 22, and is preferably in a range W40 surrounded by E2 and the left end E3 of the maximum image area. When there is an overlapping portion between the cleaning blade 22 and the cleaning blade 23a, the length of the overlapping portion is L1, and in this embodiment, L1 = 6 mm. The width W23b of the cleaning blade 23b on the right side in FIG. 5 has the same relationship as the width W23a of the cleaning blade 23a.

(Operation)
The print media 11 loaded on the paper cassette 41 are separated one by one by the hopping roller 42 and conveyed downstream. The registration roller 46 and the pinch roller 44 correct the skew of the printing medium 11 and convey it to the downstream side. Further, the transport roller 47 and the pinch roller 45 transport the print medium 11 to the process unit. The conveyed printing medium 11 passes through the process unit 15 and the transfer roller 5 to transfer the toner image. The toner image formation by the process unit 15 and the transfer by the transfer roller 5 will be described later. The print medium 15 to which the toner image has been transferred is sent to the fixing device 48 and heated and pressurized by the fixing device 48 to fix the toner image on the print medium 11. Thereafter, the print medium 11 is discharged to the stacker portion by discharge rollers 49, 50, 51, 52.

  Since the photosensitive drum 1 rotates in the direction of arrow D in FIG. 2, toner image formation, transfer, and cleaning will be described starting from a portion facing the charging roller 4. The charging roller 4 rotates in the direction of arrow H to uniformly charge the surface of the photosensitive drum 1, and the LED head 20 selectively irradiates light to form an electrostatic latent image on the photosensitive drum 1. A toner cartridge 12 for storing toner is provided in the process unit 15. The toner is supplied from the toner cartridge 12 to the process unit 15, and the toner is supplied to the developing roller 2 by the toner supply roller 3 that rotates in the direction of arrow F. Toner adheres to 2. Further, the toner adhering to the developing roller 2 by the toner blade 10 in contact with the developing roller 2 rotating in the direction of arrow E forms a thin toner layer. The electrostatic latent image on the photosensitive drum 1 is developed by the developing roller 2 on which the toner thin layer is formed, and a toner image is formed on the photosensitive drum 1.

  The toner image on the photosensitive drum 1 is transferred to the print medium 11 by the transfer roller 5 that rotates in the direction of arrow G. After transfer onto the printing medium 11, there are residual transfer toner in the printing area and toner adhering in the non-printing area on the photosensitive drum 1, and the former is mostly the toner remaining on the photosensitive drum 1, and the latter is the former. Less than The toner on the photosensitive drum 1 after the transfer is first cleaned by the cleaning blade 22 and then cleaned by the cleaning blade 23. The toner cleaned by the cleaning blades 22 and 23 is accumulated in the toner reservoir 26, and is transported as waste toner to a waste toner storage unit (not shown) as waste toner as necessary.

  Since the cleaning blade 22 is positioned upstream of the cleaning blade 23 in the rotation direction D of the photosensitive drum 1, the cleaning blade 22 first cleans the transfer residual toner in the printing area on the photosensitive drum 1 after the transfer, Next, the cleaning blade 23 cleans the adhered toner in the non-printing area on the photosensitive drum 1 after the transfer. When the cleaning blade 22 is positioned on the downstream side of the cleaning blade 23, the portion where the cleaning region overlaps with the cleaning blade 22, 23 is cleaned by the cleaning blade 23, and the amount of toner reaching the cleaning blade 22 is extremely small. In order to clean the transfer residual toner in the printing region, the cleaning blade 22 has a higher pressure contact pressure than the cleaning blade 23 and a relatively high rebound resilience of the blade. For this reason, if the amount of toner reaching the cleaning blade 22 is very small, there is no toner that acts as a lubricant during cleaning, and the frictional resistance (coefficient) between the cleaning blade 22 and the photosensitive drum 1 is in that portion. As a result, the turn-up occurs on the rotation direction D side of the photosensitive drum 1. Therefore, it is preferable that the cleaning blade 22 is positioned upstream of the cleaning blade 23.

<< Other modifications >>
The cleaning blade 22 and the cleaning blade 23 are not limited to urethane elastomers, and any rubber material, metal material, or metal oxide may be used as long as the toner can be cleaned from the photosensitive drum 1, and the cleaning blade 22 and the cleaning blade 23 are of the same quality. Even blades based on materials may be based on different materials. Further, the pressure of contact between the cleaning blade 22 and the cleaning blade 23 when contacting the photosensitive drum 1 may be the same. Further, the elastic bodies constituting the cleaning blade 22 and the cleaning blade 23 may have the same rebound resilience.

  In the first embodiment, the cleaning region WCL is cleaned by the two cleaning blades of the cleaning blade, but the cleaning region WCL may be cleaned by one cleaning unit. Further, as long as the transfer residual toner can be cleaned from the photosensitive drum 1, the cleaning means A and B indicated by the cleaning blade are not limited to the blade form, and may be a roller form or a brush form.

  The cleaning units A and B indicated by the cleaning blade start from the position where the photosensitive drum 1 and the developing roller 2 face each other as in the embodiment, and the cleaning unit A performs cleaning on the downstream side of the transfer roller 5 in the rotational direction of the photosensitive drum 1. Although it is located on the upstream side of the means B, the positions of the cleaning means A and B may be switched so that the cleaning means B is located on the upstream side of the cleaning means A.

  It is most desirable that the overlapping portion L1 is 0 mm. However, when the component tolerance of the cleaning blades 22 and 23 is taken into consideration, the overlapping portion L1 is 6 mm at the maximum, and when the mounting tolerance is taken into consideration, the overlapping portion L1 of 10 mm at the maximum is required. Therefore, the overlapping portion L1 between the cleaning blade 22 and the cleaning blade 23 may be in a range of 0 mm ≦ L1 ≦ 10 mm, and at least a range of 0 mm ≦ L1 ≦ 6 mm is necessary.

  The toners cleaned by the cleaning means A and B indicated by the cleaning blade are separately cleaned by the same toner reservoir even if the toner reservoirs are separately installed and the toners cleaned in the respective toner reservoirs are accumulated. The toner may be accumulated. Of the toners that have been cleaned and accumulated in the toner reservoir, possible toners may be used again as recycled toners as developers.

(Effect of Example 1)
As described above, according to the first embodiment, the adhesion toner in the non-printing area, in particular, the toner damaged at the contact portion between the developing roller and the seal member is cleaned from the photosensitive drum 1, thereby deteriorating the print quality. And the problem of toner leakage can be solved.

  In the process unit of the second embodiment, for toner remaining on the photosensitive drum 1 after the transfer, a means is provided for cleaning the adhering toner in the non-printing area in the same manner as the transfer residual toner in the printing area, and the transfer residual in the printing area. The toner after cleaning the toner is returned to the developing means using a cleaning roller, a photosensitive drum, and a developing roller so that the toner can be recycled.

(Constitution)
The configuration of the image forming apparatus is almost the same as that of the first embodiment, and the configuration inside the process unit is different. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  6 and 7 show the configuration of the process unit 16 according to the second embodiment. The process unit 16 includes a photosensitive drum 1 that carries an image, a toner 9 that is a developer, a developing roller 2 that supplies the toner 9 to the photosensitive drum 1, a toner supply roller 3 that supplies toner to the developing roller 2, and a developing roller 2. A toner blade 10 for forming a thin toner layer, a charging roller 4 for charging the surface of the photosensitive drum 1, a toner cartridge 12 for containing toner 9, a seal member 21 for preventing toner leakage, a cleaning blade 24 as a cleaning means, and a cleaning roller 25 A toner reservoir 26 and a holder 29 for fixing the cleaning blade 24 to the frame of the process unit 16 are formed below the cleaning blade 24. The cleaning blade 24 is in contact with the photosensitive drum 1 on the upstream side in the rotational direction of the photosensitive drum 1 with respect to the rotational direction D of the photosensitive drum 1 starting from the opposing portion of the photosensitive drum 1 and the charging roller 2. The cleaning roller 25 is in contact with the photosensitive drum 1 on the downstream side of the cleaning blade 24. The image forming apparatus includes an LED head 20 serving as an exposure device and a transfer roller 5 that transfers a toner image to the print medium 11. The cleaning blade 24 has a leading edge pressed against the surface of the photosensitive drum 1 in the same manner as the cleaning blade 22 shown in FIG.

  8 is a cross-sectional view taken along the line BB ′ in FIG. FIG. 8 shows the photosensitive drum 1, the developing roller 2, the toner supply roller 3, the seal members 21a and 21b, the cleaning blades 24a and 24b, the cleaning roller 25, and their widths. The width of the cleaning roller 25 that contacts the photosensitive drum 1 is W25, and the width that the cleaning blades 24a and 24b contact the photosensitive drum 1 is W24a and W24b, respectively, and at least one of the cleaning blade 24 and the cleaning roller 25 is cleaned. Is WCL. The width between the seal members (= toner supply roller width) sandwiched between the seal members 21a and 21b in contact with both ends of the surface of the developing roller 2 is W3, and the width of the developing roller 2 is W2. Of the printing media to be used, the maximum paper width is defined as the maximum paper width W11. Among the print media in use, the maximum image area of the paper having the maximum width is W30, and the relationship between the lengths is W3 ≧ W25 ≧ W30. The width W24 of the cleaning blade 24 will be described with reference to the left side of FIG. 8 and the width W24a. One end of the cleaning blade 24a is outside the end E1 outside the seal member 21a. The other end of the cleaning blade 24a is within a range W40 surrounded by the left end E2 of the cleaning roller 25 and the left end E3 of the maximum image area. If there is an overlapping portion between the cleaning roller 25 and the cleaning blade 24-a, the length of the overlapping portion is L1. The width W24b of the cleaning blade 24b on the right side in FIG. 8 has the same relationship as the width W24a of the cleaning blade 24a.

(Operation)
Since the photosensitive drum 1 rotates in the direction of arrow D in FIG. 6, toner image formation, transfer, and cleaning will be described starting from a portion facing the charging roller 4. The charging roller 4 rotates in the direction of arrow H to uniformly charge the surface of the photosensitive drum 1, and the LED head 20 selectively irradiates light to form an electrostatic latent image on the photosensitive drum 1. A toner cartridge 12 for storing toner is provided in the process unit 16. The toner is supplied from the toner cartridge 12 to the process unit 16, and the toner is supplied to the developing roller 2 by the toner supply roller 3 that rotates in the direction of arrow F. Toner adheres to 2. Further, the toner adhering to the developing roller 2 by the toner blade 10 in contact with the developing roller 2 rotating in the direction of arrow E forms a thin toner layer. The electrostatic latent image on the photosensitive drum 1 is developed by the developing roller 2 on which the toner thin layer is formed, and a toner image is formed on the photosensitive drum 1.

The toner image on the photosensitive drum 1 is transferred to the print medium 11 by the transfer roller 5 that rotates in the direction of arrow G.
After transfer onto the printing medium 11, there are residual transfer toner in the printing area and adhering toner in the non-printing area on the photosensitive drum 1, and the amount of toner remaining on the photosensitive drum 1 is large in the former and the latter is Less than the former. The toner on the photosensitive drum 1 after the transfer is cleaned as follows.

  Since the cleaning blade 24 is positioned upstream of the cleaning roller 25 in the rotation direction of the photosensitive drum 1, the cleaning blade 24 first cleans the toner adhering to the non-printing area on the photosensitive drum 1 after the transfer. The toner cleaned by the cleaning blade 24 is accumulated in the toner reservoir 26 below the cleaning blade, and is conveyed to a waste toner storage unit (not shown) as waste toner as necessary. Next, the transfer residual toner in the printing area remaining on the photosensitive drum 1 is subjected to a Coulomb force by the cleaning roller 25 rotating in the direction of arrow I when a voltage of +400 V is applied from a power source (not shown). Therefore, the transfer residual toner in the negatively charged printing area adheres to the cleaning roller 25, so that the transfer residual toner in the printing area is cleaned from the photosensitive drum 1. The toner cleaned by the cleaning roller 25 is temporarily accumulated on the surface of the cleaning roller 25, moved from the surface of the cleaning roller 25 to the photosensitive drum 1 by a toner recycling operation described later, and returned to the developing roller 2 and recycled.

  The toner recycling operation will be described. As described above, during the printing operation, the cleaning roller 25 cleans the transfer residual toner on the photosensitive drum 1, so that the toner accumulated on the cleaning roller 25 is discharged during non-printing. At this time, even during non-printing, the photosensitive drum 1, the cleaning roller 25, and the developing roller 2 rotate in the arrow D direction as in the printing operation.

  First, the voltage applied to the cleaning roller 25 is switched from +400 V to −1350 V by a power source (not shown), and a Coulomb force is applied to the photosensitive drum 1 side that has become a surface potential of about −50 to −300 V by discharge after the transfer process. The negatively charged toner accumulated on the cleaning roller 25 adheres to the photosensitive drum 1. The surface of the photosensitive drum 1 is charged to −800 V by the cleaning roller 25. The photosensitive drum 1 to which the toner adheres rotates and contacts the charging roller 4. However, since the charging roller 4 is supplied with a negative voltage of −1350 V from a power source (not shown), the toner on the photosensitive drum 1 continues to be photosensitive. The drum 1 receives a Coulomb force and continues to adhere to the photosensitive drum 1.

  The photosensitive drum 1 further rotates and contacts the developing roller 2. At this time, a power source (not shown) that supplies a voltage to the developing roller 2 is switched from a negative voltage supply to a 0 V supply. Therefore, the toner on the photosensitive drum 1 moves to the developing roller 2 side under the Coulomb force, and the developing roller 2 collects the toner. Thus, the toner cleaned by the cleaning roller 25 is returned to the developing roller 2 by the toner recycling operation and recycled.

  Thus, the toner cleaned by the cleaning roller 25 is recycled. For this reason, the toner in the portion where the cleaning region overlaps with the cleaning blade 24 and the cleaning roller 25 includes the toner adhering to the non-printing region, and therefore it is preferable not to collect the toner on the cleaning roller 25. Therefore, in toner cleaning on the photosensitive drum 1 after transfer, the toner is first removed by the cleaning blade 24, and the toner in the overlapping portion does not reach the cleaning roller 25, so the cleaning blade 24 is more sensitive than the cleaning roller 25. It is preferable that the drum 1 is positioned upstream in the rotation direction.

<< Other modifications >>
The cleaning means A indicated by the cleaning roller 25 and the cleaning means B indicated by the cleaning blade 24 start from the opposing position of the photosensitive drum 1 and the developing roller 2 as in the embodiment, and the transfer roller 5 rotates in the rotational direction of the photosensitive drum 1. On the downstream side, the cleaning unit A is positioned downstream of the cleaning unit B. However, the cleaning units A and B may be switched, and the cleaning unit B may be positioned downstream of the cleaning unit A. .

  It is most desirable that the overlapping portion L1 is 0 mm. However, when the component tolerances of the cleaning roller 25 and the cleaning blade 24 are taken into consideration, the overlapping portion L1 is 6 mm at the maximum, and when the mounting tolerance is taken into consideration, the overlapping portion L1 has a maximum of 10 mm. Therefore, the overlapping portion L1 between the cleaning roller 25 and the cleaning blade 24 may be in a range of 0 mm ≦ L1 ≦ 10 mm, and at least a range of 0 mm ≦ L1 ≦ 6 mm is required.

(Effect of Example 2)
As described above, according to the second embodiment, the printing quality is improved by cleaning the toner adhered to the non-printing region, particularly the toner damaged at the contact portion between the developing roller and the seal member, from the photosensitive drum 1. In addition, the toner after the transfer residual toner in the printing area is cleaned is returned to the developing means using a cleaning roller, a photosensitive drum, and a developing roller, and damaged. Only good toner was made available for recycling.

  The present invention can be applied to a printer, a facsimile, a copying machine based on an electrophotographic system, and a process unit of a device having them in combination. Further, the present invention can be applied not only to a process cartridge in which toner can be replenished with a toner cartridge or the like, but also to an integrated process cartridge that has a lifetime by using up the prefilled toner.

1 is a schematic diagram of an image forming apparatus according to a first exemplary embodiment. FIG. 3 is a configuration diagram of a process unit according to the first embodiment. 3 is a perspective view of a main part of a process unit according to Embodiment 1. FIG. 3 is an enlarged view of the tip of the cleaning blade 22 of Example 1. FIG. 1 is a cross-sectional view taken along line AA ′ of Example 1. FIG. FIG. 6 is a configuration diagram of a process unit according to a second embodiment. FIG. 6 is a perspective view of a main part of a process unit according to a second embodiment. 6 is a cross-sectional view taken along the line BB ′ of Example 2. FIG. It is a block diagram of the conventional process unit. It is conventional CC 'sectional drawing.

Explanation of symbols

1: Photosensitive drum 2: Developing roller 3: Toner supply roller 4: Charging roller 5: Transfer roller 9: Toner 10: Toner blade 11: Print medium 12: Toner cartridge 20: LED head 21: Seal member

Claims (12)

An image carrier and a developing unit that is disposed to face the image carrier and supplies a developer to the image carrier to make a visible image;
A seal member located in the vicinity of each end portion of the developing means, in contact with the surface of the developing means, and preventing leakage of the developer;
Cleaning means for contacting the surface of the image carrier and removing the developer on the image carrier;
The cleaning unit is in contact with at least a region of the image carrier facing the surface of the developing unit that is in contact with the seal member.   The cleaning means comprises two cleaning means, the first cleaning means is in contact with at least the area of the image carrier that is in contact with the surface of the developing means that is in contact with the seal member, and the second cleaning means is at least as described above. 2. The process unit according to claim 1, wherein the image bearing member is in contact with the image bearing member within a range of the surface of the developing member facing the region sandwiched between the seal members.   3. The process unit according to claim 2, wherein the first cleaning unit is located downstream of the second cleaning unit in the rotation direction of the image carrier.   3. The process unit according to claim 2, wherein the second cleaning unit is located downstream of the first cleaning unit in the rotation direction of the image carrier.   5. The process unit according to claim 3, wherein an area to be cleaned by the first cleaning unit and an area to be cleaned by the second cleaning unit have an overlapping portion.   The process unit according to claim 5, wherein the overlapping portion is located in a range of 0 mm to 10 mm.   3. A process unit according to claim 2, wherein the second cleaning means is a cleaning roller.   8. The process unit according to claim 7, wherein the developer held on the surface of the cleaning roller is attached to the image carrier and collected by the developing means.   The process unit according to claim 1, further comprising a collecting unit that collects the developer removed by the cleaning unit.   3. The process unit according to claim 2, wherein the first cleaning means has a lower pressure contact with the image carrier than the second cleaning means.   3. The process unit according to claim 2, wherein the first cleaning unit has a lower rebound resilience of an elastic body constituting the cleaning unit than the second cleaning unit.   An image forming apparatus comprising the process unit according to claim 1.

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