Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
  • G03G21/0005—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium
  • G03G21/0011—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium using a blade; Details of cleaning blades, e.g. blade shape, layer forming
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
  • G03G2221/0005—Cleaning of residual toner

Definitions

• the present invention relates to a flexible cleaning member for removing a developer on an image bearing member in contact with the image bearing member.
• a latent image is formed on a photosensitive drum, as the image bearing member which has been uniformly charged, by effecting selective light exposure and the latent image is visualized with toner as the developer to form a toner image, and then the toner image is transferred onto a recording material to effect image recording. After the toner image is transferred, a surface of the photosensitive drum is cleaned by the cleaning member and prepares for subsequent image formation.
• a cleaning means for cleaning the photosensitive drum surface a cleaning device for cleaning the photosensitive drum surface by bringing an elastic blade consisting of a rubber or the like as the cleaning member into contact with the photosensitive drum surface has been known (e.g., Japanese Laid-Open Patent Application (JP-A)
• the cleaning member With respect to setting during mounting of the cleaning member in the cleaning device, the cleaning member is disposed so as to assume a phantom straight shape of the photosensitive drum in an unloaded condition free from the photosensitive drum to obtain a desired contact pressure.
• the toner is liable to pass through the cleaning member and
• principal object of the present invention is to provide a small-sized cleaning member capable of realizing stable cleaning.
• a cleaning member for use in an image forming apparatus in which a developer image formed on an image bearing member is to be transferred onto a developer image receiving member to form an image, for removing a developer remaining on the image bearing member after the transfer, the cleaning member comprising:
• an elastic blade portion having flexibility, for removing the developer remaining on the image bearing member in contact with the image bearing member in a bent state
• the elastic blade portion includes, in a cross section perpendicular to a longitudinal
• cleaning member is used in the image forming apparatus, a first connecting portion for connecting the contact portion and a portion of the supporting portion close to the image bearing member, and a second connecting portion for connecting the contact portion and a portion of the supporting portion remote from the image bearing member, and
• a cleaning member for use in an image forming apparatus in which a developer image formed on an image bearing member is to be transferred onto a developer image receiving member to form an image, for removing a developer remaining on the image bearing member after the transfer, the cleaning member comprising:
• an elastic blade portion having flexibility, for removing the developer remaining on the image bearing member in contact with the image bearing member in a bent state
• the elastic blade portion includes, in a cross section perpendicular to a longitudinal
• cleaning member is used in the image forming apparatus, a first connecting portion for connecting the contact portion and a portion of the supporting portion close to the image bearing member, a second connecting portion for connecting the contact portion and a portion of the supporting portion remote from the image bearing member, and a foam member provided in an area defined by the supporting portion, the contact portion, the first connecting portion, and
• foam member is softer than the image connecting portion and the second connecting portion.
• Figure 1 is a schematic sectional view of a cleaning device in Embodiment 1.
• Figure 2 is a schematic sectional view of an image forming apparatus in Embodiment 1.
• Figure 3 is a schematic view for illustrating a state in which a cleaning member contacts a
• Figures 4 (a) to 4 (d) are schematic sectional views each showing a cleaning member.
• Figure 5(a) is a graph showing a result of measurement of a contact pressure while changing an entering amount (penetration depth)
• Figure 5(b) is a graph showing a result of measurement of a contact angle while changing the entering amount.
• Figures 6(a) to 6(c) are schematic sectional views each showing a cleaning member in Embodiment 2.
• Figure 7 is a graph showing changes in contact pressure with the entering amounts of the cleaning members shown in Figures 6(a) to 6(c).
• Figure 8 is a graph showing changes in contact angle with the entering amounts of the cleaning members shown in Figures.6(a) to 6(c).
• the present invention relates to an image forming apparatus, such as a copying machine or a laser printer, of an electrophotographic type or an electrostatic recording type, in which an image is formed on a recording material.
• the present invention relates to a flexible cleaning member for removing a developer on an image bearing member in contact with the image bearing member.
• Figure 2 is a schematic sectional view showing the image forming apparatus in this embodiment. An image forming operation of the image forming apparatus will be described.
• Laser light modulated depending on an image signal is outputted in a scanning manner from a scanner unit 1 including a laser, a polygon mirror and a lens system, so that a surface of a photosensitive drum 2 as the image bearing member is irradiated with the laser light.
• the photosensitive drum 2 is
• a primary charger 3 including a charging roller so that an electrostatic latent image is formed on the surface of the photosensitive drum 2 by the irradiation with the laser light.
• electrostatic latent image is developed with a toner 41 as the developer in a developing device 4, thus being visualized as a toner image (developer image) .
• a recording material toner
• (developer) image receiving member) 7 accommodated in a cassette 71 is fed and conveyed by a feeding roller 72 to a transfer charger 6 including a transfer roller in synchronism with the latent image formation on the photosensitive drum 2 and then, the toner image is transferred from the photosensitive drum 2 onto the recording material 7 by the transfer charger 6.
• the recording material 7 on which the toner image is transferred is conveyed into a fixing device 8, by which the toner image is permanently fixed on the recording material 7. Thereafter, the recording material 7 is discharged to the outside of the image forming apparatus .
• the toner remaining on the photosensitive drum 2 after the transfer is removed (subjected to
• a cleaning device 5 including an elastic blade portion 58 having flexibility.
• the elastic blade portion 58 contacts the photosensitive drum 2 in a bent state, so that the toner remaining on the photosensitive drum 2 is removed.
• the primary charger 3, the developing device 4 and the transfer charger 6 constitute an image forming portion (image forming means) 10.
• Figure 1 is a schematic sectional view of the cleaning device 5 in this embodiment.
• the cleaning device 5 includes a cleaning member 51 to be contacted to the photosensitive drum 2 counterdirectionally to a rotational develop indicated by an arrow A of the photosensitive drum 2 and
• a residual toner container 56 for containing residual toner removed from the surface of the photosensitive drum 2 by the cleaning member 51.
• the cleaning member 51 includes the elastic blade portion 58 and a supporting portion (supporting member) 55 and is held relative to the photosensitive drum 2 with a predetermined positional relationship.
• the elastic blade portion 58 is constituted by a contact portion (contact member) 52, a first connecting member) 53 and a second connecting portion (connecting member) 54.
• a hollow area 57 is formed and defined by the supporting portion 53, the contact portion 52, the first connecting portion 53 and the second connecting portion 54.
• the cross section is taken at a position in which the developer (toner) image is formed on the photosensitive drum 2 with respect to the longitudinal direction of the elastic blade portion 58.
• the longitudinal direction of the elastic blade portion 58 corresponds to a rotational axis develop of the photosensitive drum 2 and a widthwise develop of the recording material and is perpendicular to a recording material conveyance develop.
• the supporting portion 55 supports the entire cleaning member 58.
• the contact portion 52 is contacted to the photosensitive drum 2 and is formed with an elastic member.
• the image connecting portion 53 connects the supporting portion 55 and the contact portion 52 on a side where the elastic blade portion 58 is close to the photosensitive drum 2, and is formed with an elastic member.
• the first connecting portion 53 connects the supporting portion 55 and the contact portion 52 on a side where the elastic blade portion 58 is close to the photosensitive drum 2, and is formed with an elastic
• connecting portion 53 connects the contact portion 52 and a first surface 55a of the supporting portion 55 as a portion close to the photosensitive drum 2.
• the second connecting portion 54 connects the supporting portion 55 and the contact portion 52 on a side where the elastic blade portion 58 is remote from the photosensitive drum 2, and is formed with the elastic member.
• the second connecting portions 54 connects the contact portion 52 and a second surface 55b of the supporting portion 55 as a portion remote from the photosensitive drum 2.
• Figure 3 is a schematic sectional view for illustrating the contact state of the cleaning member 51 with the photosensitive drum 2.
• the cleaning member 51 is fixed so that a contact edge and the photosensitive drum 2 have a predetermined positional relationship in an unloaded state of the cleaning member 51 (indicated by a broken line in Figure 3), i.e., is fixed at a position determined by an entering amount (penetration depth) ⁇ and a set angle ⁇ .
• the entering amount ⁇ is a length, in the unloaded state of the cleaning member indicated by the broken line in Figure 3, from a point 52c of intersection of the contact portion 52 (broken line) and an outer peripheral surface of the
• the contact edge 52b is an edge of the contact portion 52 in the unloaded state when the cleaning member 51 is virtually caused to enter the photosensitive drum 2.
• the set angle ⁇ is formed between the first connecting portion 53 (solid line) and a tangent line of the outer peripheral surface of the photosensitive drum 2 passing through the point 52c in the unloaded state of the cleaning member 51 indicated by the broken line in Figure 3.
• the contact portion 52 and the first and second connecting portions 53 and 54 of the cleaning member 51 are deformed, so that a contact edge 52a contacts the surface of the photosensitive drum 2 at a contact angle ⁇ with a contact pressure P.
• the contact angle ⁇ is formed between the tangent line of the outer peripheral surface of the photosensitive drum 2 passing through the contact edge 52a contacting the photosensitive drum 2 and the contact portion 52 or the first connecting portion 53 in the neighborhood of the contact edge 52a.
• a contact state of the contact portion 52 determined by the contact pressure P and the contact angle ⁇ may only be required to be in a predetermined range in order to realize stable and good cleaning performance.
• the contact pressure is excessively low, a force for scraping (removing) the toner deposited on the drum surface becomes small, so that there is a possibility that the toner passes through the elastic blade to cause defective cleaning.
• the contact pressure is excessively large, particularly in the case where the contact pressure is increased by increasing the entering amount, the contact angle becomes small and thus a contact area between the photosensitive drum 2 surface and the contact portion 52 is increased.
• the present inventor has found that the predetermined contact condition can be satisfied under a set
• Figure 4 (a) is a schematic sectional view of the cleaning member 51 in this embodiment.
• dimensions of respective portions are indicated in Figure 4(a) (unit: mm).
• the dimensions of the respective portions are determined on the basis of a point 0 and correspond to lengths from the point 0.
• a metal plate is used as the supporting portion 55, and as the contact portion 52, the image connecting portion 53 and the second connecting portion 54, urethane rubber as an
• a cleaning member 151 prepared by using the same
• urethane rubber is shown in Figure 4 (b) together with dimensions of respective portions.
• Figure 4 (C) is a schematic view showing a deformation state when the cleaning member 51 in this embodiment is disposed in contact with the
• the cleaning member 51 principally appears at a position in which the first connecting portion 53 and the second connecting portion 54 are deformed in substantially parallel to each other, and the contact portion 52 contacts the surface of the photosensitive drum 2 in a state n which the contact portion 52 substantially keeps the set angle in the unloaded state (broken line) .
• the second connecting portion 54 functions as a supporting bar to suppress a change in contact angle of the contact portion 52 due to deformation of the first connecting portion 53 and the contact portion 52 in a develop in which the contact angle is decreased.
• the conventional cleaning member 151 is basically formed in a single plate shape, so that the contact portion is deformed in the direction in which the contact angle is decreased as the cleaning member 151 enters the photosensitive drum 2.
• the contact pressure is 47 g/cm or more and 68 g/cm or less and the contact angle is 10 degrees or more and 15 degrees or less.
• the setting condition satisfying this contact condition is such that the set angle is 25 degrees and the entering amount is 0.7 mm or more and 1.0 mm or less, i.e., the range of a difference in entering amount of 0.3 mm in the conventional embodiment ("CONV. EMB . " ) .
• EMB the setting condition is enlarged so that the set angle is 25 degrees and the entering amount is 1.4 or more and 1.9 mm or less, i.e., the range of a difference in entering amount of 0.5 mm.
• a result print test actually conducted is shown in Table 1.
• SA represents the set angle (degrees) .
• EA represents the entering amount (mm) .
• the range in which the good cleaning can be effected is 0.3 mm as the difference in entering amount of 0.7 mm or more and 1.0 mm or less in the conventional embodiment.
• a cross-sectional area of the rubber portion was 23.2 mm2 in the conventional embodiment and was 19.2 mm2 in this embodiment, so that the cleaning member in this embodiment was able to be downsized to about 80 % of the conventional cleaning member.
• the cleaning member in this embodiment it is possible to realize downsizing and good cleaning performance.
• the thickness of the first connecting portion 3 is changed.
• a difference in constitution from Embodiment 1 will be described and the same constitution as Embodiment 1 will be omitted from the description.
• Figures 6(a) to 6(c) are schematic views each showing the cleaning member 51 in this embodiment.
• the thickness tl is increased to 0.6 mm and 0.8 mm, respectively, while keeping the thickness t2 of 0.4 mm.
• dimensions (unit: mm) of the respective portions are indicated similarly as in Figures 4 (a) and 4 (b) .
• Figure 7 is a graph showing a result of measurement of a change in contact pressure with the entering amount of the cleaning members 51 shown in Figures 6(a), 6(b) and 6(c).
• Figure 8 is a graph showing a result of measurement of a change in contact angle with the entering amount of the cleaning members 51 shown in Figures 6(a), 6(b) and 6(c).
• the contact of the cleaning member 51 can be increased by increasing the thickness of the first connecting portion 53. Further, as shown in Figure 8, the contact angle with respect to the entering amount does not so depend on the thickness of the first connecting portion 53. As described in. this embodiment, by adjusting the thicknesses of the first connecting portion 53 and the second connecting portion 54 as desired, it is possible to select the shape of the cleaning member 51 capable of obtaining a desired contact pressure.
• the urethane rubber as the number material (elastic rubber member) integrally formed in the substantially U-shape was used. Therefore, in an area in which the developer image is formed, when the cross section of the elastic blade portion 58 is taken in a develop perpendicular to the longitudinal direction, a hollow area 57 is always present at any develop.
• the present invention is not limited thereto.
• a reinforcing portion for reinforcing the first connecting portion 53 and the second connecting portion 54 may be
• the hollow area 57 is not present in the cross section. However, in view of the effect of the present invention, a state in which the hollow area 57 is provided along the longitudinal direction is preferred.
• the hollow area 57 defined by the supporting portion 55, the contact portion 52, the first connecting portion 53 and the second connecting portion 54 is described but the present invention is not limited thereto.
• a foam(ed) member capable of volume change may be provided in the hollow area 57.
• Softness hardness
• a known rubber hardness meter e.g., an Asker-C hardness meter
• measuring portion is small, e.g., a piece of a sample having a 1 cm-cubic shape may be prepared and
• the cleaning member 51 and the members constituting the cleaning member 51 can be treated during manufacturing since the foam member functions as a back-up member
• the longitudinal end portions of the cleaning member 51, the area 57 defined by the supporting portion 55, the contact portion 52, the first connecting portion 53 and the second connecting portion 54 may preferably be blocked so that the area 57 is configured as a closed space but the present invention is not limited thereto.
• a member for blocking the area 57 may be separately provided on the image forming apparatus main assembly side. As a result, by mounting the cleaning member 51 into the image forming apparatus main assembly, the area 57 is blocked, so that it is possible to suppress the toner to enter the area 57.
• the first connecting portion 53 and the second connecting portion 54 are provided in substantially parallel to each other in the unloaded state but the present invention is not limited thereto.
• the first and second connecting portions 53 and 54 may also be constituted so that a distance (spacing) therebetween on the contact portion 52 side is smaller than that on the supporting portion 55 side.
• the first and second connecting portions 53 and 54 may also be constituted so that the distance therebetween is gradually decreased from the supporting portion 55 toward the contact portion 52. That is, the first and second connecting portions 53 and 54 may be configured so that the deformation of the contact portion 52 in the direction in which the contact angle is decreased as the cleaning member 51 enters the photosensitive drum 2 is suppressed by providing the second
• the image forming apparatus of the type in which the toner image is directly transferred from the photosensitive drum 2onto the recording material 7 is described but the present invention is not limited thereto. It is also possible to form an image on the recording material 7 by employing the image forming apparatus of the type in which the toner image is transferred from the photosensitive drum 2 onto an intermediary transfer member (toner image receiving member) and then is transferred from the intermediary transfer member onto the recording material 7.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Cleaning In Electrography (AREA)

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Citations (4)

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• 2010
  • 2010-12-06 JP JP2010271701A patent/JP5751813B2/ja not_active Expired - Fee Related
  • 2010-12-08 WO PCT/JP2010/072508 patent/WO2011071180A1/en active Application Filing
  • 2010-12-08 US US13/388,175 patent/US8737900B2/en not_active Expired - Fee Related

Patent Citations (4)

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