EP3349066B1 - Unit, process cartridge and image forming apparatus - Google Patents
Unit, process cartridge and image forming apparatus Download PDFInfo
- Publication number
- EP3349066B1 EP3349066B1 EP17200587.8A EP17200587A EP3349066B1 EP 3349066 B1 EP3349066 B1 EP 3349066B1 EP 17200587 A EP17200587 A EP 17200587A EP 3349066 B1 EP3349066 B1 EP 3349066B1
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- European Patent Office
- Prior art keywords
- unit
- opening
- developing
- bearing member
- toner
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Images
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
- G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
- G03G15/0887—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity
- G03G15/0891—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity for conveying or circulating developer, e.g. augers
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
- G03G15/0896—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
- G03G15/0896—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894
- G03G15/0898—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894 for preventing toner scattering during operation, e.g. seals
-
- 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
- G03G21/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements
- G03G21/18—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements using a processing cartridge, whereby the process cartridge comprises at least two image processing means in a single unit
- G03G21/1803—Arrangements or disposition of the complete process cartridge or parts thereof
- G03G21/1814—Details of parts of process cartridge, e.g. for charging, transfer, cleaning, developing
-
- 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
- G03G21/20—Humidity or temperature control also ozone evacuation; Internal apparatus environment control
- G03G21/206—Conducting air through the machine, e.g. for cooling, filtering, removing gases like ozone
-
- 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
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/18—Cartridge systems
- G03G2221/183—Process cartridge
- G03G2221/1853—Process cartridge having a submodular arrangement
- G03G2221/1869—Cartridge holders, e.g. intermediate frames for placing cartridge parts therein
Definitions
- the present invention relates to a unit according to the preamble of claim 1, a process cartridge, and an electrophotographic image forming apparatus.
- a generic unit according to the preamble of claim 1 is shown by WO 2016/136241 A1 .
- This document also shows a process cartridge and an image forming apparatus.
- Another unit, process cartridge and image forming apparatus are shown by US 2011/008068 A1 .
- a process cartridge type image forming apparatus e.g. copier, printer
- a configuration separated into a plurality of units such as a photosensitive member unit which includes a photosensitive drum, a developing unit which includes a developing means, and a toner unit which supplies toner (developer)
- the developing unit (developing apparatus) in the image forming apparatus normally includes a developer container, a developing roller which is a developer bearing member disposed at the developing opening of the developer container, and a developing blade which extends toward the developing roller to control the layer thickness of toner.
- a sheet member which extends toward the developing roller, is installed in order to prevent toner leakage inside the developer container through the developing opening and gaps with the developing roller. Further, on both ends of the developing opening in the longitudinal direction, seal members to fill the gaps with the developing roller, the developing blade and the sheet member are installed.
- the developing unit places importance on first-printout-time (FPOT), whereby the developing chamber, in which the developing roller is installed, is disposed above the toner storing member, and a sheet type toner conveying member is rotatably installed in the toner storing member.
- the toner conveying member may convey air that exists in the toner storing chamber, along with toner, and may increase the internal pressure of the developing chamber considerably.
- printers become faster with a longer life span, supplying more toner to the developing chamber is demanded, and for this, an increase in the rotation speed of the toner conveying member and an increase in the thickness of the conveying unit are required.
- This may further increase the internal pressure of the developing chamber, and cause toner leakage through the sheet member which is in light contact, and the end seal member which has a configuration that easily generates a gap.
- toner may directly contact the filter member when toner is supplied, or toner lifted up by the driving of the developing toner or the toner supplying roller may adhere to the filter member, causing the filter member to clog. This may cause a drop in the ventilation capability of the filter member, and diminish the effect of suppressing the internal pressure of the developing chamber.
- the present invention provides a technique to suppress the rise of the internal pressure of a unit in which the developer is stored.
- the technique is provided by a unit having the features of claim 1, by a process cartridge comprising this unit, and by an image forming apparatus comprising this unit. Further advantageous developments of the invention are set out in the dependent claims.
- the present invention provides a unit as specified in claims 1 to 13.
- the present invention provides a process cartridge as specified in claim 14.
- the present invention provides an image forming apparatus as specified in claim 15.
- the present invention is applicable to an electrophotographic image forming apparatus in which a developing unit, a photosensitive member unit (also called a “cleaning unit”), a process cartridge and the like are detachable from the apparatus main body.
- the electrophotographic image forming apparatus (hereafter also called “image forming apparatus”) forms an image on a recording material (recording medium) using an electrophotographic image forming system.
- the image forming apparatus include: a copier, a printer (e.g. laser beam printer, LED printer), a facsimile machine, a wordprocessor, and an integrated machine thereof (a multifunction printer).
- the apparatus main body refers to a component of the image forming apparatus excluding the above units and cartridges.
- FIG. 1 is a schematic cross-sectional view of a process cartridge 7.
- FIG. 2 is a schematic cross-sectional view of the image forming apparatus 100 according to this example.
- FIG. 3 is a perspective view depicting a state of process cartridges 7 which are installed in the apparatus main body of the image forming apparatus 100.
- the image forming apparatus 100 has a plurality of image forming units, which are a first, second, third and fourth image forming units SY, SM, SC and SK to form images having yellow (Y), magenta (M), cyan (C) and black (K) colors respectively.
- the configuration and operation of the first to fourth image forming units are essentially the same, except that the color of the image to be formed is different. Therefore in the following, the image forming unit is described with omitting Y, M, C and K unless a distinction is necessary.
- the image forming apparatus 100 has four photosensitive drums 1 (1Y, 1M, 1C, 1K) as the image bearing members.
- the photosensitive drum 1 rotates in the arrow A direction, as indicated in FIG. 1 .
- a charging roller 2 and a scanner unit (exposing apparatus) 3 are disposed around the photosensitive drum 1.
- the charging roller 2 here is a charging unit to evenly charge the surface of the photosensitive drum 1.
- the scanner unit 3 is an exposing unit to form an electrostatic image (electrostatic latent image) on the photosensitive drum 1 by irradiating a laser based on the image information.
- a developing apparatus (hereafter called “developing unit”) 4 (4Y, 4M, 4C, 4K) and a cleaning blade 6 (6Y, 6M, 6C, 6K), which is a cleaning unit, are disposed.
- the photosensitive drum 1, a charging roller 2, and a cleaning blade 6 constitute a photosensitive member unit 13 (13Y, 13M, 13C, 13K) having a removed developer storing portion (hereafter called a "waste toner storing portion") 14a (14aY, 14aM, 14aC, 14aK).
- untransferred toner (waste toner)
- the developing unit 4 performs contact development by contacting a developing roller 22, which is a developer bearing member to carry toner (developer), on the photosensitive drum 1. For the toner, a non-magnetic one component developer is stored.
- the developing unit 4 and the photosensitive member unit 13 are integrated to a process cartridge 7.
- the process cartridge 7 is detachable from the main body of the image forming apparatus 100 via an inserting unit, such as an inserting guide and a positioning member (not illustrated), disposed in the main body of the image forming apparatus 100.
- the process cartridge 7 can be inserted into the main body of the image forming apparatus 100 in the arrow G direction in FIG. 3 , which is the axis line direction of the photosensitive drum 1.
- the shape of the process cartridge 7 for each color is identical, and in the process cartridge 7 for each color, toner T (TY, TM, TC, TK) of each yellow (Y), magenta (M), cyan (C) and black (K) color is stored respectively.
- the intermediate transfer belt 5 contacts all the photosensitive drums 1, and rotates in the arrow B direction in FIG. 2 .
- the intermediate transfer belt 5 is wound around a plurality of supporting members (driver roller 26, secondary transfer counter roller 29, and driven roller 28).
- Four primary transfer rollers 8 (8Y, 8M, 8C, 8K), which are primary transfer units, are disposed in parallel on the inner surface side of the intermediate transfer belt 5, so as to face each photosensitive drum 1.
- a secondary transfer roller 9, which is a secondary transfer unit, is disposed on the outer surface side of the intermediate transfer belt 5 at a position facing the secondary transfer counter roller 29.
- the developing unit 4 has a developing frame 18 which supports various composing elements in the developing unit 4.
- yhe developing roller 22 which is a developer bearing member, is disposed so as to contact the photosensitive drum 1, and rotate in the arrow D direction in FIG. 1 (counterclockwise). Both ends of the developing roller 22, in the longitudinal direction (rotation axis line direction), are rotatably supported by the developing frame 18 via bearings.
- the developing frame 18 includes a developer storing chamber (hereafter called “toner storing chamber”) (first chamber) 18a as the developer storing portion, a developing chamber (second chamber) 18b, and a developer supply opening (first opening) (hereafter called “toner supply opening”) 18c.
- the developer supply opening 18c connects the toner storing chamber 18a and the developing chamber 18b.
- the developer supply opening 18c is formed at a partition portion (partition portion 18m in FIG. 1 ), which separates the toner storing chamber 18a and the developing chamber 18b.
- the developing chamber 18b is located above the toner storing chamber 18a.
- a toner supply roller 20, that is, a supply member which contacts the developing roller 22 and rotates in the arrow E direction, and a developing blade 21, that is, a developer controlling member to control the toner layer on the developing roller 22, are disposed.
- the developing blade 21 contacts the surface of the developing roller 22, as illustrated in FIG. 1 .
- the developing roller 22 and the toner supply roller 20 rotate such that the surface of the developing roller 22 and the surface of the toner supply roller 20 move in the same direction at a mutually contacting portion.
- the rotation direction of the developing roller 22 and the rotation direction of the toner supply roller 20 are the opposite from each other.
- a stirring member (conveying member) 23 which stirs the stored toner T, allows the toner to flow into the developing chamber 18b via the toner supply opening 18c, and then conveys the toner to the toner supply roller 20, is disposed.
- the stirring member 23 includes a rotation shaft 23a disposed in parallel with the rotation axis direction of the developing roller 22, and a stirring sheet 23b, which is a flexible sheet member of which one end is installed in the rotation shaft 23a, stirs and conveys the toner.
- the directions of the rotation axis line of the stirring member 23 and the rotation axis line of the stirring sheet 23b are parallel with the direction of the rotation axis line of the developing roller 22, and the center of the rotation shaft 23a is the rotation axis lines of the stirring member 23 and the stirring sheet 23b.
- the photosensitive member unit 13 includes a cleaning frame 14, which is a frame to support various composing elements in the photosensitive member unit 13.
- the photosensitive drum 1 is installed so as to be rotatable in the arrow A direction (clockwise) in FIG. 1 via a bearing member.
- a charging roller bearing 15 is installed along the line passing through the rotation center of the charging roller 2 and the rotation center of the photosensitive drum 1.
- the charging roller bearing 15 is installed to be movable in the arrow C direction in FIG. 1 .
- the charging roller 2 is rotatably installed on the charging roller bearing 15.
- the charging roller bearing 15 is biased by a charging roller pressurizing spring 16, which is a biasing unit, so as to press the charging roller 2 against the photosensitive drum 1.
- the waste toner removed from the surface of the photosensitive drum 1 by the cleaning blade 6 drops into the space formed by the cleaning blade 6 and the cleaning frame 14 in the gravity direction, and is stored in the waste toner storing portion 14a.
- FIG. 4A is a schematic perspective view of the developing unit 4 of this example.
- FIG. 4B is a perspective view of the developing unit 4 in the state when the bearing unit 26 and the developing roller 22 are removed from the state in FIG. 4A.
- FIG. 4C is a perspective view of the developing unit 4 in the state when an elastic sheet 24, a developing blade 21 and an end seal member 25 are removed from the state in FIG. 4B.
- FIG. 4D is a schematic cross-sectional view of the developing unit 4 in the state in FIG. 4B .
- the developing chamber 18b includes: an upper edge portion 18h, a lower edge portion 18j, and both side portions 18k.
- the developing roller 22, which carries toner is rotatably installed via the bearing unit 26, such that a part of the developing roller 22 is exposed outside the developing frame 18 via the developing opening 18d.
- the developing blade 21, which extends toward the surface of the developing roller 22 so as to control the toner layer thickness on the developing roller 22, is installed on the lower edge portion 18j side of the developing opening 18d.
- the elastic sheet 24 (corresponding to the sealing sheet) is installed on the upper edge portion 18h side of the developing opening 18d.
- the upper edge portion 18h is a fixed portion to which the elastic sheet 24 is fixed.
- the base portion of the elastic sheet 24 is installed in the developing frame 18, and the tip portion of the elastic sheet 24 contacts the developing roller 22, so as to prevent developer leakage from the developing unit 4.
- the length of the developing opening 18d in the direction of the rotation axis line of the developing roller 22 is longer than the length of the developing opening 18d in the direction orthogonal to the direction of the rotation axis line of the developing roller 22.
- the longitudinal direction of the developing opening 18d is the same as the direction of the rotation axis line of the developing roller 22.
- the transverse direction of the developing opening 18d is the same as the direction orthogonal to the direction of the rotation axis line of the developing roller 22.
- the upper edge portion 18h and the lower edge portion 18j are edge portions extending along the longitudinal direction of the developing opening 18d.
- Both side edge portions 18k correspond to the end portions of the developing openings 18d in the longitudinal direction.
- both side edge portions 18k are edge portions extending along the transverse direction of the developing opening 18d.
- the end seal member 25 is disposed on both side edge portions 18k of the developing opening 18d respectively, so as to seal each gap with the developing frame 18, the developing roller 22, the developing blade 21, and the elastic sheet 24.
- the end seal member 25 is a flexible member that press-contacts the peripheral surface of the developing roller 22, the rear surface of the developing blade 21, and the rear surface of the elastic sheet 24 when the end seal member 25 is installed in the developing unit 4. Thereby the developing unit 4 is sealed in the axis direction of the developing roller 22. In other words, as illustrated in FIGS.
- the elastic sheet 24 contacts the developing roller 22 in the area between the inner end portion of the end seal member 25 disposed on one end and the inner end portion of the end seal member 25 disposed on the other end.
- the elastic sheet 24 and the end seal member 25 both have a function of a sealing member which prevents developer leakage through an area between the developing frame 18 and the developing roller 22.
- FIGS. 5A to 5E are schematic cross-sectional views of the process cartridge 7.
- the stirring sheet 23b which is a convey unit, contacts the inner wall surface of the toner storing chamber 18a, and the stirring member 23, which is a developer conveying member, rotates at 100 rpm in the state where the stirring sheet 23b is bent.
- the toner storing chamber 18a has a release position 18e where the stirring sheet 23b is released from the bent state.
- the stirring sheet 23b flips up the toner laying on the stirring sheet 23b by the force generated when the stirring sheet 23b is released from the bent state, and conveys the toner to the toner supply roller 20 inside the developing chamber 18b through the toner supply opening 18c.
- the stirring sheet 23b is deformable, and conveys toner by release of this deformation.
- the tip portion of the stirring sheet 23b, the rotation shaft 23a, and the toner supply opening 18c are disposed to satisfy the following relationship in the direction orthogonal to the rotation axis line of the stirring sheet 23b.
- the length of the stirring sheet 23b is set such that even the toner on the bottom 18f of the toner storing chamber 18a can be stirred and conveyed.
- the length W0 from the center of the rotation shaft 23a to the tip portion of the stirring sheet 23b, with respect to the length W1 from the center of the rotation shaft 23a to the bottom 18f of the toner storing chamber 18a satisfies W0 > W1.
- the length W0 is set such that the relationship, with respect to the length W2 from the center of the rotation shaft 23a to the lower end of the toner supply opening 18c, satisfies W0 > W2.
- the distance between the tip of the stirring sheet 23b in the undeformed state and the rotation axis line of the stirring sheet 23b is longer than the shortest distance between the opening 18c and the rotation axis line of the stirring sheet 23b.
- FIG. 5A depicts the state of toner when the stirring sheet 23b is in the phase of starting to push the upper surface (interface) of the deposited toner. Then the stirring sheet 23b rotates in the arrow F direction in FIGS. 5A to 5E . The stirring sheet 23b, which reached the phase in FIG. 5B , lifts up and conveys the toner. Then the stirring sheet 23b rotates in the arrow F direction, and the stirring sheet 23b reaches the phase of the release position 18e, as illustrated in FIG. 5C .
- the toner in-convey is on the stirring sheet 23b, and immediately after the stirring sheet 23b passes the release position 18e, the stirring sheet 23b is released from the bent state, and the toner is flipped up toward the toner supply opening 18c. Then, as illustrated in FIG. 5D , the stirring sheet 23b conveys the toner to the toner supply opening 18c using the force that returns from the bent state to the released state, and collides with the toner supply opening 18c so as to push the toner into the developing chamber 18b. Then the stirring sheet 23b rotates in the arrow F direction, and enters the phase of the stirring sheet 23b in FIG. 5A again.
- the stirring sheet 23b rotates continuously in the arrow F direction, and toner on the stirring sheet 23b is flipped up every time the stirring sheet 23b passes the phase of the release position 18e, whereby toner is successively conveyed to the developing chamber 18b through the toner supply opening 18c.
- the developing opening 18d is an opening which connects the toner storing chamber 18a and the developing chamber 18b, so that the toner in-convey can pass from the toner storing chamber 18a to the developing chamber 18b.
- the toner conveyed from the toner storing chamber 18a passes through the toner supply opening 18c, passes above the toner supply roller 20, and is conveyed toward the developing opening 18d (arrow H direction in FIG. 5D ). Further, the toner conveyed to the developing opening 18d is conveyed to the contact portion between the supply roller 20 and the developing roller 22, and a part of the toner is supplied to the developing roller 22.
- the toner, not supplied to the developing roller 22, is conveyed to a region J, which is surrounded by the developing blade 21, the developing roller 22, the toner supply roller 20, and the lower end of the toner supply opening 18c in the developing chamber 18b, by the rotation of the developing roller 22 and the toner supply roller 20.
- the length W0 from the rotation shaft 23a to the tip of the stirring sheet 23b, with respect to the length W2 from the rotation shaft 23a to the lower end of the toner supply opening 18c is set to be W0 > W2, this means that at this time, the string sheet collides with the portion where the toner supply opening 18c is formed in the portion wall 18m.
- toner leakage caused by an increase in the pressure inside the developing chamber 18b, is effectively suppressed by disposing the ventilation opening (second opening) 18g and the filter member (hereafter called "filter") 27.
- the stirring member 23 rotates at 100 rpm (rotates 100 times per minute). This is because a high-speed processing speed is demanded (conventionally about 75 rpm).
- the pressure inside the frame 18 can be easily increased by the rotation of the stirring member 23, and if the internal pressure is high, toner more easily scatters and toner leakage, as mentioned above, is a concern.
- FIG. 6A is a perspective view of the process cartridge 7
- FIG. 6B is a perspective view of the process cartridge 7 in the state when the filter 27 is removed.
- the ventilation opening 18g is a surface constituting the developing chamber 18b, and is extending in the longitudinal direction of the developing unit 4, so as to connect to outside the developing unit 4.
- the ventilation opening 18g connects inside the developing chamber 18b with outside the developing frame 18 in the cross-sectional direction, which is orthogonal to the rotation axis line of the stirring sheet 23b (orthogonal direction with respect to the direction of the rotation axis line of the stirring sheet 23b).
- the ventilation opening 18g is disposed in a wide rectangular region which is long in the longitudinal direction of the developing unit 4, so as to extend from one end to the other end of the developing roller 22.
- the length of the ventilation opening 18g in the rotation axis line direction of the stirring sheet 23b is longer than the length of the ventilation opening 18g in the direction orthogonal to the rotation axis line direction of the stirring sheet 23b (transverse direction of the developing unit 4).
- the ventilation opening 18g and the opening 18c are configured to intersect with a single cross-section of the stirring member 23 in the orthogonal direction with respect to the rotation axis line of the stirring member 23.
- FIG. 1 and FIG. 4D the ventilation opening 18g and the opening 18c are configured to intersect with a single cross-section of the stirring member 23 in the orthogonal direction with respect to the rotation axis line of the stirring member 23.
- the ventilation opening 18g and the opening 18c face each other so that a rectangular virtual region can be formed by the ventilation opening 18g, the opening 18c, and two virtual lines (L1, L2) connecting the ends of the ventilation opening 18g and the opening 18c when viewing the cross-section orthogonal to the rotation axis line of the stirring member 23.
- L1, L2 virtual lines connecting the ends of the ventilation opening 18g and the opening 18c when viewing the cross-section orthogonal to the rotation axis line of the stirring member 23.
- the range of the ventilation opening 18g and the range of the opening 18c at least partially overlap with each other in the axis line direction of the rotation shaft 23a (longitudinal direction).
- the ventilation opening 18g connects inside the developing chamber 18b and outside the developing frame 18 ( FIG. 1 ).
- the ventilation opening 18g is disposed in at least one location, and as the area of the ventilation opening 18g becomes larger, the effect of releasing pressure improves.
- the ventilation opening 18g is disposed in two locations, in order to obtain a sufficient rigidity in the frame and a high ventilation effect.
- the ventilation opening 18g is disposed on two locations in this example.
- the ventilation opening 18g is not disposed at the center of the developing opening 18d in the longitudinal direction of the developing opening 18d.
- each ventilation opening 18g is disposed in a position that is shifted from the center position of the developing opening 18d respectively.
- the center position of the developing opening 18d overlaps with the position of the connection wall 18n of the ventilation opening 18g.
- connection wall 18n which is the wall surface closest to the developing opening 18d
- pressure can be effectively decreased in an area near the developing opening 18d.
- rigidity of the developing frame 18 especially the connection wall 18n
- the rigidity of the developing frame 18 can be improved at the center area in the longitudinal direction.
- a convex portion 18p is disposed around the ventilation opening 18g.
- the rigidity of the developing frame 18 can be improved in an area around the ventilation opening 18g.
- the convex portion 18p extends along the longitudinal direction and in the transverse direction of the ventilation opening 18g respectively.
- Each convex portion 18p is disposed for both ventilation openings 18g.
- the convex portion 18p may have a portion which extends in the transverse direction at the center of the longer side of the opening 18c, so as to cross the ventilation opening 18g.
- the line connecting one end of the ventilation opening 18g and one end of the opening 18c in the direction orthogonal to the rotation shaft 23c is the first line L1.
- the line connecting the other end of the ventilation opening 18g and the other end of the opening 18c is the second line L2.
- the region between the first line L1 and the second line L2 is a region which includes the shortest path out of the paths for the air that passed through the opening 18c to reach the ventilation opening 18g.
- at least a part of the supply roller 20 is located outside the region between the first line L1 and the second line L2.
- connection wall 18n is connected to the fixed portion (upper edge portion 18h).
- the connection wall 18n extends in the orthogonal direction (direction orthogonal to the direction of the rotation axis line of the developing roller 22, or the rotation axis line of the stirring sheet 23b), so as to cross the extending direction of the elastic sheet 24.
- the connection wall 18n can be regarded as a wall surface which supports the fixed portion (upper edge portion 18h) in the thickness direction of the elastic sheet 24.
- the ventilation opening 18g is disposed on the upper surface (connection wall 18n) of the developing frame 18. In this case, the region J inside the developing chamber 18b is always filled with toner, and the ventilation opening 18g should be disposed on a surface which does not constitute the region J.
- the wall surface on which the ventilation opening 18g is disposed is a wall surface of which one side forms the inner wall of the developing chamber 18b, and the other side forms a part of the outer wall of the developing frame 18.
- the size of the ventilation opening 18g can be increased by disposing the ventilation opening 18g on the largest wall surface among such wall surfaces.
- the ventilation opening 18g is disposed at the upstream side of the developing opening 18d on the toner conveying path (arrow mark H in FIG. 5D ). Therefore the air conveyed from the toner storing chamber 18a is discharged from the ventilation opening 18g before reaching the developing opening 18d, where toner leakage more easily occurs. Thereby the pressure inside the developing chamber 18b can be effectively decreased, and toner leakage can be suppressed. Furthermore, the ventilation opening 18g is disposed in the developing chamber 18b in an area close to both the ends. Thereby the increase in pressure toward the end seal member 25 disposed in the end portion of the developing opening 18d can be effectively suppressed, and toner leakage can be controlled.
- the filter 27 is disposed to cover the ventilation opening 18g, and is constituted by a material which prevents toner leakage inside the developing unit 4 (passing of toner through the ventilation openings 18g), and allows air, inside the developing unit 4, to pass through.
- the filter 27 allows air to pass through the ventilation opening 18g, and stops toner from passing through.
- the filter 27 is larger than the ventilation opening 18g when viewed in the normal line direction of the surface on which the filter 27 is fixed. It is preferable that the material of the filter 27 has high air permeability. The higher the air permeability, the more the ventilation effect improves, and a higher inner pressure reduction effect can be achieved. This means that a greater effect in preventing toner leakage can be obtained.
- the filter 27 is welded to the developing frame 18 from outside the wall surface of the developing frame 18.
- the method for fixing the filter 27 to the developing frame 18 is not limited to welding, but may be double-sided tape, adhesive or the like.
- the filter 27 may be fixed from inside the developing unit 4.
- the filter 27 may also be integrated with the developing frame 18, such as insert-molded in the developing unit.
- the filter 27 can be fixed in any way as long as air can pass, and toner leakage through the ventilation opening 18g can be prevented.
- the number of filters 27 is one or more, and is not limited to a specific number.
- two filters 27 cover the two ventilation openings 18g.
- the number of ventilation openings 18g and the number of filters 27 need not be the same, and, for example, one filter 27 may cover a plurality of ventilation openings 18g.
- the ventilation openings 18g and the filter 27 may be disposed as illustrated in FIGS. 8A to 8C.
- FIGS. 8A to 8C show examples of the positions of the ventilation openings 18g and the filters 27 according to this example.
- FIGS. 8A to 8C show schematic diagrams when the ventilation openings 18g, the filters 27, the opening 18c and the developing opening 18d are viewed in the direction orthogonal to the rotation axis line direction of the stirring sheet 23b.
- the arrow P indicates the rotation axis line direction of the stirring sheet 23b.
- portions other than the ventilation openings 18g, the filters 27, the opening 18c and the developing opening 18d are omitted.
- one region and the other region of the developing opening 18d may have a single ventilation opening 18g respectively (each ventilation opening 18g covers approximately the entire area of each region respectively).
- the shape of the ventilation opening 18g is not limited to a rectangle as illustrated, but may be various different shapes, such as a rectangle with rounded corners, and an ellipse.
- a plurality of ventilation openings 18g may be disposed side by side in the longitudinal direction in the above mentioned one region and the other region respectively (each ventilation opening 18g in FIG. 8A is divided in the longitudinal direction).
- the number of ventilation openings 18g disposed in each region is not limited to the number illustrated in FIG. 8B , but may be two, or more than three respectively.
- the shape and size of each ventilation opening 18g may be the same shape and size as illustrated in FIG. 8B , or may be different from each other.
- each ventilation opening 18g the length in the longitudinal direction (rotation axis line direction of the stirring sheet 23b) may be longer or shorter than the length in the transverse direction (transverse direction of the developing unit 4), which is orthogonal to the longitudinal direction.
- a plurality of ventilation openings 18g may be disposed side by side in the transverse direction for each region of the developing opening 18d.
- the number of ventilation openings 18g disposed in the transverse direction is not limited to the number illustrated in FIG. 8C , but may be three or more.
- the number of ventilation openings 18g of each row disposed in the transverse direction, the shapes and sizes thereof, and the arrangement thereof are not limited to the configuration illustrated in FIG. 8C , where the number of ventilation openings 18g is different between rows, and the shapes and sizes of the ventilation openings 18g are different from one another, and the ventilation openings 18g in the top and bottom rows are disposed alternately.
- the ventilation openings 18g may be disposed in a lattice, where the same number, the same shape and the same size of the ventilation openings 18g are disposed and aligned in each row.
- the material of the filter is a non-woven fabric, of which the average pore diameter is 5 ⁇ m, in order to obtain both collectability and permeability.
- the photosensitive drum 1 ( ⁇ 30 perfect circle) is initially rotating at 300 rpm in the arrow A direction. Then the surface of the photosensitive drum 1 is uniformly charged by the charging roller 2.
- the charging roller 2 is a ⁇ 20 conductive rubber roller, and is driven and rotated by pressing the roller portion against the photosensitive drum 1, and a predetermined DC voltage is applied to the core metal of the charging roller 2 in the charging step for the photosensitive drum 1. Thereby a uniform dark electric potential (Vd) is formed.
- an electrostatic latent image of a predetermined light electric potential (Vl) is formed in the exposed portion of the photosensitive drum 1
- an electrostatic latent image of a predetermined dark electric potential (Vd) is formed in the unexposed portion on the photosensitive drum 1.
- the electrostatic latent image formed on the photosensitive drum 1 contact with toner which the developing unit 4 conveyed to the developing roller 22, is developed, and becomes a toner image.
- Toner that is used in this example has a degree of agglomeration of 5% to 40%, and an average particle diameter of 8 ⁇ m in non-used state. In order to ensure the flowability of toner for its entire lifespan, it is desirable to use toner having this degree of agglomeration.
- the degree of agglomeration of toner was measured as follows.
- a powder tester made by Hosokawa Micro Corporation
- a digital vibration meter Digital Vibration Meter Model 1332, manufactured by Showa Sokki Corporation
- 390 mesh, 200 mesh and 100 mesh sieves were stacked up on a vibration table in the sequence of smaller sieve openings, that is, in the sequence of the 390 mesh, 200 mesh and 100 mesh sieves, with the 100 mesh sieve on top.
- an accurately measured 5 g sample (toner) is placed on the 100 mesh sieve that is set as mentioned above
- the displacement value of the digital vibration meter was adjusted to 0.60 mm (peak-to-peak), and vibration was applied for 15 seconds.
- the mass of the sample remaining on each sieve was measured, and the degree of agglomeration was obtained based on the following expression.
- the toner image formed on the photosensitive drum 1 is transferred onto the intermediate transfer belt 5 (primary transfer) by the function of the primary transfer roller 8.
- the above mentioned processing is sequentially performed by the first to fourth image forming units SY, SM, SC and SK, and a toner image of each color is sequentially superimposed on the intermediate transfer belt 5 as the primary transfer. Then synchronizing with the movement of the intermediate transfer belt 5, the recording material 12 is conveyed to the secondary transfer unit. Then by the function of the secondary transfer roller 9, which is in contact with the intermediate transfer belt 5 via the recording material 12, the four-color toner images on the intermediate transfer belt 5 are transferred onto the recoding material 12 in batch as the secondary transfer.
- the recording material 12, on which the toner image was transferred is conveyed to the fixing apparatus 10, which is a fixing unit.
- the toner image is fixed to the recording material 12 by the fixing apparatus 10 applying heat and pressure to the recording material 12, and the recording material 12 is discharged at about a 60 ppm speed.
- the removed untransferred toner (waste toner) is discharged to a waste toner box (not illustrated) of the image forming apparatus 100.
- the image forming apparatus 100 can also form a single color or a multi-color image using only a desired single or some (not all) image forming units.
- FIG. 7A is a schematic enlarged view of the filter position when an image is formed (developing contact time)
- FIG. 7B is a schematic enlarged view of the filter position when an image is not formed (developing separation time).
- the process cartridge 7 is configured such that the developing roller 22 and the photosensitive drum 1 can be in contact/separated, and the relative position of the developing unit 4 (first unit) and the photosensitive member unit 13 (second unit) can be changeable.
- the developing unit 4 (developing frame 18) rotates around the developing contact/separation support point 17, and changes the position (angle with respect to the photosensitive member unit 13) depending on whether a pressurized unit 18i is pressed by a pressurizing unit 80 of a developing contact/separation mechanism disposed in the image forming apparatus 100.
- the developing unit 4 takes a position with respect to the photosensitive member unit 13: either a contacted state where the photosensitive drum 1 and the developing roller 22 are in contact (corresponding to the contact position or the second position); or a separated state where the photosensitive drum 1 and the developing roller 22 are separated (corresponding to the separated position or the first position). This makes the developing separation of the photosensitive drum 1 and the developing roller 22 possible.
- the developing unit 4 can move between the contact position and the separation position (the contact position can be displaced with respect to the apparatus main body).
- the second position of the developing frame 18 may be a position where the developing roller 22 and the photosensitive drum 1 are in proximity separated by a gap.
- the developing unit 4 of this example is configured such that the distance between the developing roller 22 and the photosensitive drum 1 at the first position of the developing frame 18 is longer than the distance between the developing roller 22 and the photosensitive drum 1 at the second position of the developing frame 18.
- the position of the developing unit 4, with respect to the photosensitive member unit 13 changes (rotates) with the developing contact/separation support point 17 at the predetermined rotation shaft as the support point, and the developing roller 22 separates from the photosensitive drum 1.
- the developing frame 18 rotates around the support point 17.
- the developing separation amount is 10 mm, and the upper surface (corresponding to the filter installation surface) on which the filter 27 is disposed, becomes horizontal in the separation state.
- the exposed surface of the filter 27 (surface of the filter 27 on the developing storing unit side), which is exposed to the inside of the developing frame 18 (developer storing portion), is also horizontal or at an angle close to horizontal.
- the angle between the horizontal surface and the exposed surface is 0° or close to 0°.
- the developing unit 4 rotates around the developing contact/separation support point 17, and is displaced with respect to the photosensitive member unit 13 by the elastic force (biasing force) of a developing contact spring 181 which is an biasing member.
- the biasing force to change the position of the developing frame 18 with respect to the cleaning frame 14 from the separation position to the contact position, is always applied.
- the upper surface becomes 30° with respect to the horizontal direction.
- the surface of the filter 27, exposed to the inside of the developing frame 18, also has a 30° or closer angle.
- the angle between the horizontal surface and the exposed surface is 30° or close to 30°.
- the angle between the horizontal surface and the exposed surface changes between the contact state and the separation state.
- the angle between the horizontal surface and the exposed surface in the separation state is smaller than the angle between the horizontal surface and the exposed surface in the contact state.
- the position of the filter 27 can also be changed as illustrated in FIGS. 7A and 7B .
- toner is gradually collected in the concave portions on the surface of the filter 27 by the supply of toner from the stirring member 23, and by the scattering of toner due to the rotation of the toner supply roller 20 and the developing roller 22.
- toner adheres to the exposed surface of the filter 27, which is exposed to the inside the developing frame 18.
- countless filter holes 27a, which are open in the filter 27, clog, and the ventilation capability drops considerably.
- the filter 27 is located in a position more distant from the rotation support point 17 of the developing unit 4, compared with the developing roller 22 and the toner supply roller 20, and is disposed so that the displacement amount in the contact/separation operation is more than that of the developing roller 22 and the like.
- the filter 27 is disposed such that the distance between the filter 27 and the rotation support point 17 (center of the rotary displacement) (the shortest distance, such as the distance between the right end of the filter 27 and the rotation support point 17 in the portion overlapping with the opening 18g in the cross-section in FIG.
- the distance between the developing roller 22 and the rotation support point 17 is longer than the distance between the developing roller 22 and the rotation support point 17 (the longest distance, such as a distance between the point most distant from the rotation support point 17 on the peripheral surface of the developing roller 22 and the rotation support point 17 in the cross-section in FIG. 1 ). Thereby vibration is more easily generated on the filter 27 by the contact/separation operation, and the adhering toner can be more effectively separated.
- the developing contact operation is performed during prior rotation, before forming the image, and the developing separation operation is performed during the post-rotation, after forming the image.
- the developing unit 4 is in the developing contact state while the image forming operation is performed.
- the developing unit 4 is in the developing separation state while the image forming operation is not performed.
- the filter installation surface and the developer contact surface of the filter 27 maintain the horizontal state, or at an angle close to the horizontal state while the image forming operation is not performed.
- continuous printing is interrupted every 500 prints, and the post-rotation operation is executed to perform the developing contact/separation operation, but the present invention is not limited to this. It is desirable to set the number of prints at which printing is interrupted in accordance with the configuration of the developing apparatus. Further, in this example, continuous printing is forcibly interrupted at every predetermined number of prints, and the post-rotation operation is performed so as to perform the developing contact/separation operation, but the present invention is not limited to this. For example, if the drive instruction to the developing apparatus is interrupted and the developing contact/separation operation is repeated in a state of stopping the supply of toner, a better effect to separate toner is obtained.
- the developing separation amount is zero in Comparative Example 1, and is increased respectively by 5 mm in the sequence of Comparative Example 2, Comparative Example 3 and this example. Except for this difference, the configuration of the process cartridge and the general configuration of the image forming apparatus according to Comparative Example 1, Comparative Example 2 and Comparative Example 3 are the same as this example.
- Table 1 shows the verification result.
- Presence of toner leakage Comparative Example 1 Comparative Example 2 Comparative Example 3 This example Developing contact /separation NO YES YES YES Developing separation amount 0 mm 5 mm 10 mm 15 mm Filter angle 30° 20° 10° 0° 0K prints ⁇ ⁇ ⁇ ⁇ 10K prints ⁇ ⁇ ⁇ ⁇ 20K prints ⁇ ⁇ ⁇ ⁇ 30K prints ⁇ ⁇ ⁇ ⁇ 40K prints ⁇ ⁇ ⁇ ⁇ 50K prints - ⁇ ⁇ ⁇ 60K prints - - ⁇ ⁇ ⁇
- Comparative Example 1 will be described first.
- the photosensitive drum 1 and the developing roller 22 are constantly in contact, and a small amount of toner leakage was observed at 30K prints, and extreme toner leakage was generated at 40K prints. In this state, toner clogged and ventilation performance dropped considerably.
- Comparative Example 2 will be described next.
- Comparative Example 2 a small amount of toner leakage was observed at 40K prints, and extreme toner leakage was generated at 50K prints.
- an improvement was observed by 10K prints. This may be because the developing separation amount was set to 5 mm for the developing separation, whereby the angle of the filter member became closer to horizontal by 10° compared with Comparative Example 1, and more toner, collected in the concave portions of the filter, fell, and a drop in ventilation capability was suppressed.
- the target 60K prints was not implemented.
- Comparative Example 3 will be described next. In the case of Comparative Example 3, a small amount of toner leakage was observed at 50K prints, and extreme toner leakage was generated at 60K prints.
- Comparative Example 4 the developing separation is forcibly performed at every 750 prints
- Comparative Example 5 the developing separation is forcibly performed at every 1000 prints. Except for this difference, the configuration of the process cartridge and the general configuration of the image forming apparatus of Comparative Example 4 and Comparative Example 5 are the same as this example.
- Table 2 shows the presence of toner leakage in this example and in the comparative examples.
- Presence of toner leakage Comparative Example 4 Comparative Example 5 This example Developing contact timing 1000 750 500 0K prints ⁇ ⁇ ⁇ 5K prints ⁇ ⁇ ⁇ 10K prints - ⁇ ⁇ 20K prints - ⁇ ⁇ 30K prints - - ⁇ 40K prints - - ⁇ 50K prints - - ⁇ 60K prints - - ⁇
- Comparative Example 4 First Comparative Example 4 will be described. In the case of Comparative Example 4, the developing separation is executed at every 1000 prints, and extreme toner leakage was generated at 5K prints.
- Comparative Example 5 Next Comparative Example 5 will be described.
- the developing separation is executed at every 750 prints, and a small amount of toner leakage was observed at 10K prints. Then extreme toner leakage was generated at 20K prints. Even performing the developing separation every 750 prints was insufficient to suppress toner clogging.
- the developing separation amount is set to 15 mm, and the developing contact/separation operation is performed every 500 prints, as described above.
- the angle of the filter member becomes closer to horizontal, and toner collected in the concave portions of the filter can easily fall by the contact/separation operation.
- the developing apparatus and the filter member are impacted by the developing contact/separation operation, whereby the toner is more easily separated from the filter member.
- filter clogging can be suppressed, and a drop in ventilation performance can be prevented, as verified in Experiment 1 and Experiment 2.
- an increase in the internal pressure of the developing chamber can be reduced or suppressed, and toner leakage from the developing unit can be prevented.
- an increase in the internal pressure of the unit in which the developer is stored can be suppressed.
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Description
- The present invention relates to a unit according to the preamble of
claim 1, a process cartridge, and an electrophotographic image forming apparatus. - A generic unit according to the preamble of
claim 1 is shown byWO 2016/136241 A1 . This document also shows a process cartridge and an image forming apparatus. Another unit, process cartridge and image forming apparatus are shown byUS 2011/008068 A1 .As a process cartridge type image forming apparatus (e.g. copier, printer), a configuration separated into a plurality of units, such as a photosensitive member unit which includes a photosensitive drum, a developing unit which includes a developing means, and a toner unit which supplies toner (developer), is known. Among these units, the developing unit (developing apparatus) in the image forming apparatus normally includes a developer container, a developing roller which is a developer bearing member disposed at the developing opening of the developer container, and a developing blade which extends toward the developing roller to control the layer thickness of toner. On the other edge of the developing opening in the longitudinal direction, a sheet member, which extends toward the developing roller, is installed in order to prevent toner leakage inside the developer container through the developing opening and gaps with the developing roller. Further, on both ends of the developing opening in the longitudinal direction, seal members to fill the gaps with the developing roller, the developing blade and the sheet member are installed. - In such a developing unit, the internal pressure may rise due to various factors. In this case, toner more easily leaks out through the sheet member and the seal member which seal the toner, and this is because of the pressure difference between the inside and outside of the developing unit. To prevent toner leakage by reducing the pressure inside the developing unit, a configuration of disposing a ventilation opening and a filter member in a developing frame has been proposed (see
JP 57517791 B2 JP 4790676 B2 - In the above mentioned developing unit, an example of a configuration is disclosed that places importance on first-printout-time (FPOT), whereby the developing chamber, in which the developing roller is installed, is disposed above the toner storing member, and a sheet type toner conveying member is rotatably installed in the toner storing member. In such a configuration, the toner conveying member may convey air that exists in the toner storing chamber, along with toner, and may increase the internal pressure of the developing chamber considerably. Furthermore, lately as printers become faster with a longer life span, supplying more toner to the developing chamber is demanded, and for this, an increase in the rotation speed of the toner conveying member and an increase in the thickness of the conveying unit are required. This may further increase the internal pressure of the developing chamber, and cause toner leakage through the sheet member which is in light contact, and the end seal member which has a configuration that easily generates a gap. Moreover, if the printer is used in a certain position for a long time, toner may directly contact the filter member when toner is supplied, or toner lifted up by the driving of the developing toner or the toner supplying roller may adhere to the filter member, causing the filter member to clog. This may cause a drop in the ventilation capability of the filter member, and diminish the effect of suppressing the internal pressure of the developing chamber.
- The present invention provides a technique to suppress the rise of the internal pressure of a unit in which the developer is stored.
The technique is provided by a unit having the features ofclaim 1, by a process cartridge comprising this unit, and by an image forming apparatus comprising this unit. Further advantageous developments of the invention are set out in the dependent claims. - The present invention provides a unit as specified in
claims 1 to 13. - The present invention provides a process cartridge as specified in
claim 14. - The present invention provides an image forming apparatus as specified in
claim 15. - Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
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FIG. 1 is a cross-sectional view of a process cartridge according to this invention; -
FIG. 2 is a schematic cross-sectional view of an image forming apparatus and process cartridges according to this invention; -
FIG. 3 is a perspective view of the image forming apparatus and process cartridges according to this invention; -
FIGS. 4A to 4D show perspective views and a cross-sectional view of a developing unit according to this invention; -
FIGS. 5A to 5E show cross-sectional views of the process cartridge according to this invention; -
FIGS. 6A and 6B show perspective views of the process cartridge according to this invention; -
FIGS. 7A and 7B show cross-sectional views depicting the states of a filter member according to this invention; and -
FIGS. 8A to 8C show diagrams depicting examples of the arrangement of ventilation openings and filters according to this invention. - Hereinafter, a description will be given, with reference to the drawings, of embodiments (examples) of the present invention. However, the sizes, materials, shapes, their relative arrangements, or the like of constituents described in the embodiments may be appropriately changed according to the configurations, various conditions, or the like of apparatuses to which the invention is applied. Therefore, the sizes, materials, shapes, their relative arrangements, or the like of the constituents described in the embodiments do not intend to limit the scope of the invention to the following embodiments.
- The present invention is applicable to an electrophotographic image forming apparatus in which a developing unit, a photosensitive member unit (also called a "cleaning unit"), a process cartridge and the like are detachable from the apparatus main body. Here the electrophotographic image forming apparatus (hereafter also called "image forming apparatus") forms an image on a recording material (recording medium) using an electrophotographic image forming system. Examples of the image forming apparatus include: a copier, a printer (e.g. laser beam printer, LED printer), a facsimile machine, a wordprocessor, and an integrated machine thereof (a multifunction printer). The apparatus main body refers to a component of the image forming apparatus excluding the above units and cartridges.
- A configuration of an electrophotographic image forming apparatus (image forming apparatus) according to an example of the present invention will be described with reference to
FIGS. 1 to 3 .FIG. 1 is a schematic cross-sectional view of aprocess cartridge 7.FIG. 2 is a schematic cross-sectional view of theimage forming apparatus 100 according to this example.FIG. 3 is a perspective view depicting a state ofprocess cartridges 7 which are installed in the apparatus main body of theimage forming apparatus 100. Theimage forming apparatus 100 has a plurality of image forming units, which are a first, second, third and fourth image forming units SY, SM, SC and SK to form images having yellow (Y), magenta (M), cyan (C) and black (K) colors respectively. In this example, the configuration and operation of the first to fourth image forming units are essentially the same, except that the color of the image to be formed is different. Therefore in the following, the image forming unit is described with omitting Y, M, C and K unless a distinction is necessary. - The
image forming apparatus 100 has four photosensitive drums 1 (1Y, 1M, 1C, 1K) as the image bearing members. Thephotosensitive drum 1 rotates in the arrow A direction, as indicated inFIG. 1 . Around thephotosensitive drum 1, acharging roller 2 and a scanner unit (exposing apparatus) 3 are disposed. Thecharging roller 2 here is a charging unit to evenly charge the surface of thephotosensitive drum 1. The scanner unit 3 is an exposing unit to form an electrostatic image (electrostatic latent image) on thephotosensitive drum 1 by irradiating a laser based on the image information. Around thephotosensitive drum 1, a developing apparatus (hereafter called "developing unit") 4 (4Y, 4M, 4C, 4K) and a cleaning blade 6 (6Y, 6M, 6C, 6K), which is a cleaning unit, are disposed. An intermediate transfer belt 5, which is an intermediate transfer member, to transfer a toner image (developer image) on thephotosensitive drum 1 to a recording material 12, is disposed so as to face the fourphotosensitive drums 1. Thephotosensitive drum 1, acharging roller 2, and acleaning blade 6 constitute a photosensitive member unit 13 (13Y, 13M, 13C, 13K) having a removed developer storing portion (hereafter called a "waste toner storing portion") 14a (14aY, 14aM, 14aC, 14aK). In the wastetoner storing portion 14a, untransferred toner (waste toner), which remained on thephotosensitive drum 1 after the toner image is transferred to the recording material 12, and was removed from thephotosensitive drum 1 by thecleaning blade 6, is stored. - The developing
unit 4 performs contact development by contacting a developingroller 22, which is a developer bearing member to carry toner (developer), on thephotosensitive drum 1. For the toner, a non-magnetic one component developer is stored. The developingunit 4 and thephotosensitive member unit 13 are integrated to aprocess cartridge 7. Theprocess cartridge 7 is detachable from the main body of theimage forming apparatus 100 via an inserting unit, such as an inserting guide and a positioning member (not illustrated), disposed in the main body of theimage forming apparatus 100. In this example, theprocess cartridge 7 can be inserted into the main body of theimage forming apparatus 100 in the arrow G direction inFIG. 3 , which is the axis line direction of thephotosensitive drum 1. The shape of theprocess cartridge 7 for each color is identical, and in theprocess cartridge 7 for each color, toner T (TY, TM, TC, TK) of each yellow (Y), magenta (M), cyan (C) and black (K) color is stored respectively. - The intermediate transfer belt 5 contacts all the
photosensitive drums 1, and rotates in the arrow B direction inFIG. 2 . The intermediate transfer belt 5 is wound around a plurality of supporting members (driver roller 26, secondarytransfer counter roller 29, and driven roller 28). Four primary transfer rollers 8 (8Y, 8M, 8C, 8K), which are primary transfer units, are disposed in parallel on the inner surface side of the intermediate transfer belt 5, so as to face eachphotosensitive drum 1. Further, asecondary transfer roller 9, which is a secondary transfer unit, is disposed on the outer surface side of the intermediate transfer belt 5 at a position facing the secondarytransfer counter roller 29. - A general configuration of the
process cartridge 7 of this example will be described with reference toFIG. 1 . The developingunit 4 has a developingframe 18 which supports various composing elements in the developingunit 4. In the developingunit 4, yhe developingroller 22, which is a developer bearing member, is disposed so as to contact thephotosensitive drum 1, and rotate in the arrow D direction inFIG. 1 (counterclockwise). Both ends of the developingroller 22, in the longitudinal direction (rotation axis line direction), are rotatably supported by the developingframe 18 via bearings. The developingframe 18 includes a developer storing chamber (hereafter called "toner storing chamber") (first chamber) 18a as the developer storing portion, a developing chamber (second chamber) 18b, and a developer supply opening (first opening) (hereafter called "toner supply opening") 18c. In the developingchamber 18b, the developingroller 22 is disposed. Thedeveloper supply opening 18c connects thetoner storing chamber 18a and the developingchamber 18b. Thedeveloper supply opening 18c is formed at a partition portion (partition portion 18m inFIG. 1 ), which separates thetoner storing chamber 18a and the developingchamber 18b. In this example, the developingchamber 18b is located above thetoner storing chamber 18a. In the developingchamber 18b, atoner supply roller 20, that is, a supply member which contacts the developingroller 22 and rotates in the arrow E direction, and a developingblade 21, that is, a developer controlling member to control the toner layer on the developingroller 22, are disposed. The developingblade 21 contacts the surface of the developingroller 22, as illustrated inFIG. 1 . - Further, as illustrated in
FIG. 1 , the developingroller 22 and thetoner supply roller 20 rotate such that the surface of the developingroller 22 and the surface of thetoner supply roller 20 move in the same direction at a mutually contacting portion. In other words, when viewing from the direction along the rotation axis line of the developingroller 22 or the rotation axis line of thetoner supply roller 20, the rotation direction of the developingroller 22 and the rotation direction of thetoner supply roller 20 are the opposite from each other. - In the
toner storing chamber 18a of the developingframe 18, a stirring member (conveying member) 23, which stirs the stored toner T, allows the toner to flow into the developingchamber 18b via thetoner supply opening 18c, and then conveys the toner to thetoner supply roller 20, is disposed. The stirringmember 23 includes arotation shaft 23a disposed in parallel with the rotation axis direction of the developingroller 22, and astirring sheet 23b, which is a flexible sheet member of which one end is installed in therotation shaft 23a, stirs and conveys the toner. In other words, the directions of the rotation axis line of the stirringmember 23 and the rotation axis line of the stirringsheet 23b are parallel with the direction of the rotation axis line of the developingroller 22, and the center of therotation shaft 23a is the rotation axis lines of the stirringmember 23 and the stirringsheet 23b. - The
photosensitive member unit 13 includes acleaning frame 14, which is a frame to support various composing elements in thephotosensitive member unit 13. In thecleaning frame 14, thephotosensitive drum 1 is installed so as to be rotatable in the arrow A direction (clockwise) inFIG. 1 via a bearing member. Further, in thecleaning frame 14, a chargingroller bearing 15 is installed along the line passing through the rotation center of the chargingroller 2 and the rotation center of thephotosensitive drum 1. Here the chargingroller bearing 15 is installed to be movable in the arrow C direction inFIG. 1 . The chargingroller 2 is rotatably installed on the chargingroller bearing 15. The chargingroller bearing 15 is biased by a chargingroller pressurizing spring 16, which is a biasing unit, so as to press the chargingroller 2 against thephotosensitive drum 1. Anelastic member 6a to remove the untransferred toner (waste toner) remaining on the surface of thephotosensitive drum 1 after the primary transfer, and asupport member 6b to support the elastic member, are integrated to thecleaning blade 6. The waste toner removed from the surface of thephotosensitive drum 1 by thecleaning blade 6 drops into the space formed by thecleaning blade 6 and thecleaning frame 14 in the gravity direction, and is stored in the wastetoner storing portion 14a. - The configuration of the developing
chamber 18b will be described with reference toFIG. 1 andFIGS. 4A to 4D. FIG. 4A is a schematic perspective view of the developingunit 4 of this example.FIG. 4B is a perspective view of the developingunit 4 in the state when the bearingunit 26 and the developingroller 22 are removed from the state inFIG. 4A. FIG. 4C is a perspective view of the developingunit 4 in the state when anelastic sheet 24, a developingblade 21 and anend seal member 25 are removed from the state inFIG. 4B. FIG. 4D is a schematic cross-sectional view of the developingunit 4 in the state inFIG. 4B . - As illustrated in
FIGS. 4C and 4D , the developingchamber 18b includes: anupper edge portion 18h, alower edge portion 18j, and bothside portions 18k. In the developingopening 18d, the developingroller 22, which carries toner, is rotatably installed via the bearingunit 26, such that a part of the developingroller 22 is exposed outside the developingframe 18 via the developingopening 18d. As illustrated inFIGS. 4A and 4B , the developingblade 21, which extends toward the surface of the developingroller 22 so as to control the toner layer thickness on the developingroller 22, is installed on thelower edge portion 18j side of the developingopening 18d. On the other hand, the elastic sheet 24 (corresponding to the sealing sheet) is installed on theupper edge portion 18h side of the developingopening 18d. In other words, theupper edge portion 18h is a fixed portion to which theelastic sheet 24 is fixed. The base portion of theelastic sheet 24 is installed in the developingframe 18, and the tip portion of theelastic sheet 24 contacts the developingroller 22, so as to prevent developer leakage from the developingunit 4. - Here, as illustrated in
FIG. 4C , the length of the developingopening 18d in the direction of the rotation axis line of the developingroller 22 is longer than the length of the developingopening 18d in the direction orthogonal to the direction of the rotation axis line of the developingroller 22. In other words, the longitudinal direction of the developingopening 18d is the same as the direction of the rotation axis line of the developingroller 22. The transverse direction of the developingopening 18d is the same as the direction orthogonal to the direction of the rotation axis line of the developingroller 22. Theupper edge portion 18h and thelower edge portion 18j are edge portions extending along the longitudinal direction of the developingopening 18d. Bothside edge portions 18k correspond to the end portions of the developingopenings 18d in the longitudinal direction. And bothside edge portions 18k are edge portions extending along the transverse direction of the developingopening 18d. - The
end seal member 25 is disposed on bothside edge portions 18k of the developingopening 18d respectively, so as to seal each gap with the developingframe 18, the developingroller 22, the developingblade 21, and theelastic sheet 24. Theend seal member 25 is a flexible member that press-contacts the peripheral surface of the developingroller 22, the rear surface of the developingblade 21, and the rear surface of theelastic sheet 24 when theend seal member 25 is installed in the developingunit 4. Thereby the developingunit 4 is sealed in the axis direction of the developingroller 22. In other words, as illustrated inFIGS. 4A to 4D , in the longitudinal direction of the developingopening 18d, theelastic sheet 24 contacts the developingroller 22 in the area between the inner end portion of theend seal member 25 disposed on one end and the inner end portion of theend seal member 25 disposed on the other end. Theelastic sheet 24 and theend seal member 25 both have a function of a sealing member which prevents developer leakage through an area between the developingframe 18 and the developingroller 22. - The configuration to convey toner inside the
toner storing chamber 18a to the developingchamber 18b will be described with reference toFIG. 1 andFIGS. 5A to 5E. FIGS. 5A to 5E are schematic cross-sectional views of theprocess cartridge 7. - The stirring
sheet 23b, which is a convey unit, contacts the inner wall surface of thetoner storing chamber 18a, and the stirringmember 23, which is a developer conveying member, rotates at 100 rpm in the state where the stirringsheet 23b is bent. Thetoner storing chamber 18a has arelease position 18e where the stirringsheet 23b is released from the bent state. When the stirringsheet 23b passes through therelease position 18e, the stirringsheet 23b flips up the toner laying on the stirringsheet 23b by the force generated when the stirringsheet 23b is released from the bent state, and conveys the toner to thetoner supply roller 20 inside the developingchamber 18b through thetoner supply opening 18c. In other words, the stirringsheet 23b is deformable, and conveys toner by release of this deformation. - As illustrated in
FIG. 1 , the tip portion of the stirringsheet 23b, therotation shaft 23a, and thetoner supply opening 18c are disposed to satisfy the following relationship in the direction orthogonal to the rotation axis line of the stirringsheet 23b. The length of the stirringsheet 23b is set such that even the toner on the bottom 18f of thetoner storing chamber 18a can be stirred and conveyed. In other words, as illustrated inFIG. 1 , the length W0 from the center of therotation shaft 23a to the tip portion of the stirringsheet 23b, with respect to the length W1 from the center of therotation shaft 23a to the bottom 18f of thetoner storing chamber 18a, satisfies W0 > W1. Furthermore, in order to stably convey the toner to the developingchamber 18b, the length W0 is set such that the relationship, with respect to the length W2 from the center of therotation shaft 23a to the lower end of thetoner supply opening 18c, satisfies W0 > W2. In other words, as illustrated inFIG. 1 , the distance between the tip of the stirringsheet 23b in the undeformed state and the rotation axis line of the stirringsheet 23b is longer than the shortest distance between theopening 18c and the rotation axis line of the stirringsheet 23b. The state of the stirringsheet 23b and toner, while the stirringmember 23 makes a complete cycle, will be described with reference toFIGS. 5A to 5E . -
FIG. 5A depicts the state of toner when the stirringsheet 23b is in the phase of starting to push the upper surface (interface) of the deposited toner. Then the stirringsheet 23b rotates in the arrow F direction inFIGS. 5A to 5E . The stirringsheet 23b, which reached the phase inFIG. 5B , lifts up and conveys the toner. Then the stirringsheet 23b rotates in the arrow F direction, and the stirringsheet 23b reaches the phase of therelease position 18e, as illustrated inFIG. 5C . The toner in-convey is on the stirringsheet 23b, and immediately after the stirringsheet 23b passes therelease position 18e, the stirringsheet 23b is released from the bent state, and the toner is flipped up toward thetoner supply opening 18c. Then, as illustrated inFIG. 5D , the stirringsheet 23b conveys the toner to thetoner supply opening 18c using the force that returns from the bent state to the released state, and collides with thetoner supply opening 18c so as to push the toner into the developingchamber 18b. Then the stirringsheet 23b rotates in the arrow F direction, and enters the phase of the stirringsheet 23b inFIG. 5A again. The stirringsheet 23b rotates continuously in the arrow F direction, and toner on the stirringsheet 23b is flipped up every time the stirringsheet 23b passes the phase of therelease position 18e, whereby toner is successively conveyed to the developingchamber 18b through thetoner supply opening 18c. In other words, the developingopening 18d is an opening which connects thetoner storing chamber 18a and the developingchamber 18b, so that the toner in-convey can pass from thetoner storing chamber 18a to the developingchamber 18b. - At this time, as illustrated in
FIG. 5D , the toner conveyed from thetoner storing chamber 18a passes through thetoner supply opening 18c, passes above thetoner supply roller 20, and is conveyed toward the developingopening 18d (arrow H direction inFIG. 5D ). Further, the toner conveyed to the developingopening 18d is conveyed to the contact portion between thesupply roller 20 and the developingroller 22, and a part of the toner is supplied to the developingroller 22. The toner, not supplied to the developingroller 22, is conveyed to a region J, which is surrounded by the developingblade 21, the developingroller 22, thetoner supply roller 20, and the lower end of thetoner supply opening 18c in the developingchamber 18b, by the rotation of the developingroller 22 and thetoner supply roller 20. When a sufficient amount of toner is supplied to the developingchamber 18b, as illustrated inFIG. 5E , the region J is filled with toner, and excessive toner returns to thetoner storing chamber 18a through thetoner supply opening 18c (arrow K direction inFIG. 5E ) by the rotation of thetoner supply roller 20. - The length W0 from the
rotation shaft 23a to the tip of the stirringsheet 23b, with respect to the length W2 from therotation shaft 23a to the lower end of thetoner supply opening 18c is set to be W0 > W2, this means that at this time, the string sheet collides with the portion where thetoner supply opening 18c is formed in theportion wall 18m. - In this example, toner leakage, caused by an increase in the pressure inside the developing
chamber 18b, is effectively suppressed by disposing the ventilation opening (second opening) 18g and the filter member (hereafter called "filter") 27. As mentioned above, in the configuration of this example, the stirringmember 23 rotates at 100 rpm (rotates 100 times per minute). This is because a high-speed processing speed is demanded (conventionally about 75 rpm). In the case of the configuration in which the stirring speed is faster than prior art, as in this example, the pressure inside theframe 18 can be easily increased by the rotation of the stirringmember 23, and if the internal pressure is high, toner more easily scatters and toner leakage, as mentioned above, is a concern. Therefore the increase in pressure must be suppressed by disposing theventilation opening 18g and thefilter 27. It is known that such a mechanism to suppress the increase in pressure is required when the rotation speed of the stirringmember 23 is 80 rpm or faster. Theventilation opening 18g and thefilter 27 will be described with reference toFIG. 1 andFIGS. 6A and 6B. FIG. 6A is a perspective view of theprocess cartridge 7, andFIG. 6B is a perspective view of theprocess cartridge 7 in the state when thefilter 27 is removed. - As illustrated in
FIG. 1 andFIGS. 6A and 6B , theventilation opening 18g is a surface constituting the developingchamber 18b, and is extending in the longitudinal direction of the developingunit 4, so as to connect to outside the developingunit 4. As illustrated inFIG. 1 , theventilation opening 18g connects inside the developingchamber 18b with outside the developingframe 18 in the cross-sectional direction, which is orthogonal to the rotation axis line of the stirringsheet 23b (orthogonal direction with respect to the direction of the rotation axis line of the stirringsheet 23b). Further, theventilation opening 18g is disposed in a wide rectangular region which is long in the longitudinal direction of the developingunit 4, so as to extend from one end to the other end of the developingroller 22. In other words, the length of theventilation opening 18g in the rotation axis line direction of the stirringsheet 23b is longer than the length of theventilation opening 18g in the direction orthogonal to the rotation axis line direction of the stirringsheet 23b (transverse direction of the developing unit 4). For example, as illustrated inFIG. 1 andFIG. 4D , theventilation opening 18g and theopening 18c are configured to intersect with a single cross-section of the stirringmember 23 in the orthogonal direction with respect to the rotation axis line of the stirringmember 23. For example, as illustrated inFIG. 1 , theventilation opening 18g and theopening 18c face each other so that a rectangular virtual region can be formed by theventilation opening 18g, theopening 18c, and two virtual lines (L1, L2) connecting the ends of theventilation opening 18g and theopening 18c when viewing the cross-section orthogonal to the rotation axis line of the stirringmember 23. In other words, when theventilation opening 18g and theopening 18c are viewed from the direction orthogonal to a virtual surface region including the opening edge of theventilation opening 18g, or the direction orthogonal to a virtual surface region including the opening edge of theopening 18c, at least a part of theventilation opening 18g overlaps with at least a part of theopening 18c. This means that the range of theventilation opening 18g and the range of theopening 18c at least partially overlap with each other in the axis line direction of therotation shaft 23a (longitudinal direction). As mentioned above, in the orthogonal direction with respect to the direction of the rotation axis line of the stirringsheet 23b, theventilation opening 18g connects inside the developingchamber 18b and outside the developing frame 18 (FIG. 1 ). By disposing theventilation opening 18g in this direction, the change in the pressure inside the developingchamber 18b, caused by the stirringsheet 23b, can be effectively reduced. - It is sufficient that the
ventilation opening 18g is disposed in at least one location, and as the area of theventilation opening 18g becomes larger, the effect of releasing pressure improves. In this example, theventilation opening 18g is disposed in two locations, in order to obtain a sufficient rigidity in the frame and a high ventilation effect. - As illustrated in
FIGS. 4A to 4D andFIG. 6A , theventilation opening 18g is disposed on two locations in this example. In this case, theventilation opening 18g is not disposed at the center of the developingopening 18d in the longitudinal direction of the developingopening 18d. In other words, in the longitudinal direction, eachventilation opening 18g is disposed in a position that is shifted from the center position of the developingopening 18d respectively. As a result, in the longitudinal direction of the developingopening 18d, the center position of the developingopening 18d overlaps with the position of the connection wall 18n of theventilation opening 18g. - By disposing the
ventilation opening 18g on the connection wall 18n, which is the wall surface closest to the developingopening 18d, pressure can be effectively decreased in an area near the developingopening 18d. Further, the rigidity of the developing frame 18 (especially the connection wall 18n) can be improved at the center area in the longitudinal direction. - Furthermore, as illustrated in
FIGS. 4A to 4D andFIGS. 5A to 5E , aconvex portion 18p is disposed around theventilation opening 18g. Thereby the rigidity of the developingframe 18 can be improved in an area around theventilation opening 18g. In this example, theconvex portion 18p extends along the longitudinal direction and in the transverse direction of theventilation opening 18g respectively. Eachconvex portion 18p is disposed for bothventilation openings 18g. Theconvex portion 18p may have a portion which extends in the transverse direction at the center of the longer side of theopening 18c, so as to cross theventilation opening 18g. - Moreover, as illustrated in
FIG. 1 , it is assumed that the line connecting one end of theventilation opening 18g and one end of theopening 18c in the direction orthogonal to the rotation shaft 23c is the first line L1. Further, it is assumed that the line connecting the other end of theventilation opening 18g and the other end of theopening 18c is the second line L2. In this case, the region between the first line L1 and the second line L2 is a region which includes the shortest path out of the paths for the air that passed through theopening 18c to reach theventilation opening 18g. In the configuration illustrated inFIG. 1 , at least a part of thesupply roller 20 is located outside the region between the first line L1 and the second line L2. Thereby it can be prevented that the region between the first line L1 and the second line L2 is decreased by thesupply roller 20. In the case of disposing a plurality ofventilation openings 18g, it is not necessary to dispose all theventilation openings 18g, as mentioned above. In other words, only a part of theventilation openings 18g and thesupply roller 20 may satisfy the above mentioned positional relationship. - As illustrated in
FIG. 1 , the connection wall 18n is connected to the fixed portion (upper edge portion 18h). The connection wall 18n extends in the orthogonal direction (direction orthogonal to the direction of the rotation axis line of the developingroller 22, or the rotation axis line of the stirringsheet 23b), so as to cross the extending direction of theelastic sheet 24. The connection wall 18n can be regarded as a wall surface which supports the fixed portion (upper edge portion 18h) in the thickness direction of theelastic sheet 24. In this example, theventilation opening 18g is disposed on the upper surface (connection wall 18n) of the developingframe 18. In this case, the region J inside the developingchamber 18b is always filled with toner, and theventilation opening 18g should be disposed on a surface which does not constitute the region J. - Further, the wall surface on which the
ventilation opening 18g is disposed is a wall surface of which one side forms the inner wall of the developingchamber 18b, and the other side forms a part of the outer wall of the developingframe 18. As illustrated inFIG. 1 , the size of theventilation opening 18g can be increased by disposing theventilation opening 18g on the largest wall surface among such wall surfaces. - The
ventilation opening 18g is disposed at the upstream side of the developingopening 18d on the toner conveying path (arrow mark H inFIG. 5D ). Therefore the air conveyed from thetoner storing chamber 18a is discharged from theventilation opening 18g before reaching the developingopening 18d, where toner leakage more easily occurs. Thereby the pressure inside the developingchamber 18b can be effectively decreased, and toner leakage can be suppressed. Furthermore, theventilation opening 18g is disposed in the developingchamber 18b in an area close to both the ends. Thereby the increase in pressure toward theend seal member 25 disposed in the end portion of the developingopening 18d can be effectively suppressed, and toner leakage can be controlled. - As illustrated in
FIG. 6B , thefilter 27 is disposed to cover theventilation opening 18g, and is constituted by a material which prevents toner leakage inside the developing unit 4 (passing of toner through theventilation openings 18g), and allows air, inside the developingunit 4, to pass through. In other words, thefilter 27 allows air to pass through theventilation opening 18g, and stops toner from passing through. As depicted inFIGS. 6A and 6B , thefilter 27 is larger than theventilation opening 18g when viewed in the normal line direction of the surface on which thefilter 27 is fixed. It is preferable that the material of thefilter 27 has high air permeability. The higher the air permeability, the more the ventilation effect improves, and a higher inner pressure reduction effect can be achieved. This means that a greater effect in preventing toner leakage can be obtained. - In this example, the
filter 27 is welded to the developingframe 18 from outside the wall surface of the developingframe 18. The method for fixing thefilter 27 to the developingframe 18 is not limited to welding, but may be double-sided tape, adhesive or the like. Thefilter 27 may be fixed from inside the developingunit 4. Thefilter 27 may also be integrated with the developingframe 18, such as insert-molded in the developing unit. Thefilter 27 can be fixed in any way as long as air can pass, and toner leakage through theventilation opening 18g can be prevented. - The number of
filters 27 is one or more, and is not limited to a specific number. In this example, twofilters 27 cover the twoventilation openings 18g. Here the number ofventilation openings 18g and the number offilters 27 need not be the same, and, for example, onefilter 27 may cover a plurality ofventilation openings 18g. In other words, theventilation openings 18g and thefilter 27 may be disposed as illustrated inFIGS. 8A to 8C. FIGS. 8A to 8C show examples of the positions of theventilation openings 18g and thefilters 27 according to this example.FIGS. 8A to 8C show schematic diagrams when theventilation openings 18g, thefilters 27, theopening 18c and the developingopening 18d are viewed in the direction orthogonal to the rotation axis line direction of the stirringsheet 23b. The arrow P indicates the rotation axis line direction of the stirringsheet 23b. InFIGS. 8A to 8C , portions other than theventilation openings 18g, thefilters 27, theopening 18c and the developingopening 18d are omitted. - As illustrated in
FIG. 8A , one region and the other region of the developingopening 18d, separated at the center of the developingopening 18d in the longitudinal direction, may have asingle ventilation opening 18g respectively (eachventilation opening 18g covers approximately the entire area of each region respectively). The shape of theventilation opening 18g is not limited to a rectangle as illustrated, but may be various different shapes, such as a rectangle with rounded corners, and an ellipse. - As illustrated in
FIG. 8B , a plurality ofventilation openings 18g may be disposed side by side in the longitudinal direction in the above mentioned one region and the other region respectively (eachventilation opening 18g inFIG. 8A is divided in the longitudinal direction). The number ofventilation openings 18g disposed in each region is not limited to the number illustrated inFIG. 8B , but may be two, or more than three respectively. The shape and size of eachventilation opening 18g may be the same shape and size as illustrated inFIG. 8B , or may be different from each other. Here in eachventilation opening 18g, the length in the longitudinal direction (rotation axis line direction of the stirringsheet 23b) may be longer or shorter than the length in the transverse direction (transverse direction of the developing unit 4), which is orthogonal to the longitudinal direction. In other words, all that is required is that the total length, adding the length of eachventilation opening 18g in each region in the longitudinal direction, is longer than the length of eachventilation opening 18g in the transverse direction. - Further, as illustrated in
FIG. 8C , a plurality ofventilation openings 18g may be disposed side by side in the transverse direction for each region of the developingopening 18d. The number ofventilation openings 18g disposed in the transverse direction is not limited to the number illustrated inFIG. 8C , but may be three or more. The number ofventilation openings 18g of each row disposed in the transverse direction, the shapes and sizes thereof, and the arrangement thereof are not limited to the configuration illustrated inFIG. 8C , where the number ofventilation openings 18g is different between rows, and the shapes and sizes of theventilation openings 18g are different from one another, and theventilation openings 18g in the top and bottom rows are disposed alternately. In other words, theventilation openings 18g may be disposed in a lattice, where the same number, the same shape and the same size of theventilation openings 18g are disposed and aligned in each row. - In this example, the material of the filter is a non-woven fabric, of which the average pore diameter is 5 µm, in order to obtain both collectability and permeability.
- When an image is formed, the photosensitive drum 1 (φ30 perfect circle) is initially rotating at 300 rpm in the arrow A direction. Then the surface of the
photosensitive drum 1 is uniformly charged by the chargingroller 2. The chargingroller 2 is a φ20 conductive rubber roller, and is driven and rotated by pressing the roller portion against thephotosensitive drum 1, and a predetermined DC voltage is applied to the core metal of the chargingroller 2 in the charging step for thephotosensitive drum 1. Thereby a uniform dark electric potential (Vd) is formed. - The spot pattern of the laser light from the scanner unit 3, which is emitted corresponding to the image data, exposes the
photosensitive drum 1, and in the exposed part, charges on the surface dissipate by the carriers from the carrier generation unit, and potential drops. As a result, an electrostatic latent image of a predetermined light electric potential (Vl) is formed in the exposed portion of thephotosensitive drum 1, and an electrostatic latent image of a predetermined dark electric potential (Vd) is formed in the unexposed portion on thephotosensitive drum 1. In this example, it is assumed that Vd = -500 V and Vl = -100 V. - The electrostatic latent image formed on the
photosensitive drum 1 contact with toner which the developingunit 4 conveyed to the developingroller 22, is developed, and becomes a toner image. Here Vdc = -300 V is applied to the developingroller 22, so as to generate ΔV = 200 V of potential difference from the light electric potential, and the toner image is formed as the developingroller 22 rotates in the driven direction with respect to the photosensitive drum at a peripheral speed difference of 150%. - Toner that is used in this example has a degree of agglomeration of 5% to 40%, and an average particle diameter of 8 µm in non-used state. In order to ensure the flowability of toner for its entire lifespan, it is desirable to use toner having this degree of agglomeration. The degree of agglomeration of toner was measured as follows.
- For the measuring device, a powder tester (made by Hosokawa Micro Corporation), including a digital vibration meter (Digital Vibration Meter Model 1332, manufactured by Showa Sokki Corporation) was used. As the measurement method, 390 mesh, 200 mesh and 100 mesh sieves were stacked up on a vibration table in the sequence of smaller sieve openings, that is, in the sequence of the 390 mesh, 200 mesh and 100 mesh sieves, with the 100 mesh sieve on top. Then an accurately measured 5 g sample (toner) is placed on the 100 mesh sieve that is set as mentioned above, the displacement value of the digital vibration meter was adjusted to 0.60 mm (peak-to-peak), and vibration was applied for 15 seconds. Then the mass of the sample remaining on each sieve was measured, and the degree of agglomeration was obtained based on the following expression.
-
- The toner image formed on the
photosensitive drum 1 is transferred onto the intermediate transfer belt 5 (primary transfer) by the function of the primary transfer roller 8. Here the primary transfer roller 8 is set to the transfer voltage Vtr = +1 kV, in order to transfer the negatively charged toner from thephotosensitive drum 1 onto the intermediate transfer belt 5. - When a full color image is formed, the above mentioned processing is sequentially performed by the first to fourth image forming units SY, SM, SC and SK, and a toner image of each color is sequentially superimposed on the intermediate transfer belt 5 as the primary transfer. Then synchronizing with the movement of the intermediate transfer belt 5, the recording material 12 is conveyed to the secondary transfer unit. Then by the function of the
secondary transfer roller 9, which is in contact with the intermediate transfer belt 5 via the recording material 12, the four-color toner images on the intermediate transfer belt 5 are transferred onto the recoding material 12 in batch as the secondary transfer. The recording material 12, on which the toner image was transferred, is conveyed to the fixing apparatus 10, which is a fixing unit. The toner image is fixed to the recording material 12 by the fixing apparatus 10 applying heat and pressure to the recording material 12, and the recording material 12 is discharged at about a 60 ppm speed. - The primary untransferred toner, which remained on the
photosensitive drum 1 after the primary transfer step, is removed by thecleaning blade 6. The secondary untransferred toner, which remained on the intermediate transfer belt 5 after the secondary transfer step, is removed by the intermediate transferbelt cleaning apparatus 11. The removed untransferred toner (waste toner) is discharged to a waste toner box (not illustrated) of theimage forming apparatus 100. Theimage forming apparatus 100 can also form a single color or a multi-color image using only a desired single or some (not all) image forming units. - The features of this example will be described with reference to
FIGS. 7A and 7B. FIG. 7A is a schematic enlarged view of the filter position when an image is formed (developing contact time), andFIG. 7B is a schematic enlarged view of the filter position when an image is not formed (developing separation time). Theprocess cartridge 7 is configured such that the developingroller 22 and thephotosensitive drum 1 can be in contact/separated, and the relative position of the developing unit 4 (first unit) and the photosensitive member unit 13 (second unit) can be changeable. The developing unit 4 (developing frame 18) rotates around the developing contact/separation support point 17, and changes the position (angle with respect to the photosensitive member unit 13) depending on whether apressurized unit 18i is pressed by a pressurizingunit 80 of a developing contact/separation mechanism disposed in theimage forming apparatus 100. Thereby the developingunit 4 takes a position with respect to the photosensitive member unit 13: either a contacted state where thephotosensitive drum 1 and the developingroller 22 are in contact (corresponding to the contact position or the second position); or a separated state where thephotosensitive drum 1 and the developingroller 22 are separated (corresponding to the separated position or the first position). This makes the developing separation of thephotosensitive drum 1 and the developingroller 22 possible. In this way, the developingunit 4 can move between the contact position and the separation position (the contact position can be displaced with respect to the apparatus main body). The second position of the developingframe 18 may be a position where the developingroller 22 and thephotosensitive drum 1 are in proximity separated by a gap. In other words, the developingunit 4 of this example is configured such that the distance between the developingroller 22 and thephotosensitive drum 1 at the first position of the developingframe 18 is longer than the distance between the developingroller 22 and thephotosensitive drum 1 at the second position of the developingframe 18. - When the
pressurized unit 18i is pressurized (pressed) by the pressurizingunit 80, the position of the developingunit 4, with respect to thephotosensitive member unit 13, changes (rotates) with the developing contact/separation support point 17 at the predetermined rotation shaft as the support point, and the developingroller 22 separates from thephotosensitive drum 1. In other words, in this example, the developingframe 18 rotates around thesupport point 17. In this example, the developing separation amount is 10 mm, and the upper surface (corresponding to the filter installation surface) on which thefilter 27 is disposed, becomes horizontal in the separation state. This means that the exposed surface of the filter 27 (surface of thefilter 27 on the developing storing unit side), which is exposed to the inside of the developing frame 18 (developer storing portion), is also horizontal or at an angle close to horizontal. In other words, in the state where the developingroller 22 is separated from thephotosensitive drum 1, the angle between the horizontal surface and the exposed surface (angle on the narrow angle side) is 0° or close to 0°. - When the applied pressure by the developing contact/separation mechanism to the
pressurized unit 18i is reduced or becomes zero, the developingunit 4 rotates around the developing contact/separation support point 17, and is displaced with respect to thephotosensitive member unit 13 by the elastic force (biasing force) of a developing contact spring 181 which is an biasing member. Thereby the developingroller 22 and thephotosensitive drum 1 contact. In other words, in the developingframe 18 of the developingunit 4, the biasing force, to change the position of the developingframe 18 with respect to thecleaning frame 14 from the separation position to the contact position, is always applied. In this case, the upper surface becomes 30° with respect to the horizontal direction. This means that the surface of thefilter 27, exposed to the inside of the developingframe 18, also has a 30° or closer angle. In other words, in the state where the developingroller 22 is in contact with thephotosensitive drum 1, the angle between the horizontal surface and the exposed surface (angle on the narrow angle side) is 30° or close to 30°. - As mentioned above, in the
filter 27, the angle between the horizontal surface and the exposed surface changes between the contact state and the separation state. In this example, the angle between the horizontal surface and the exposed surface in the separation state is smaller than the angle between the horizontal surface and the exposed surface in the contact state. - In this way, by changing the position of the developing
unit 4 using the developing contact/separation mechanism, the position of thefilter 27 can also be changed as illustrated inFIGS. 7A and 7B . In concrete terms, in the developing contact state illustrated inFIG. 7A , toner is gradually collected in the concave portions on the surface of thefilter 27 by the supply of toner from the stirringmember 23, and by the scattering of toner due to the rotation of thetoner supply roller 20 and the developingroller 22. In other words, toner adheres to the exposed surface of thefilter 27, which is exposed to the inside the developingframe 18. In this case,countless filter holes 27a, which are open in thefilter 27, clog, and the ventilation capability drops considerably. In particular, if the stirringmember 23 rotates in the arrow F direction in the developing contact state, air is supplied toward thetoner supply opening 18c of the developingchamber 18b, where theventilation opening 18g and thefilter 27 are disposed on the wall surface, by the movement of the stirringsheet 23b. Because of this configuration, toner is easily collected in the concave portions on the surface of thefilter 27. In the developing separation state illustrated inFIG. 7B , on the other hand, the toner collected in the concave portions easily fall in the vertical direction due to gravity. As a result, the toner around thefilter holes 27a is eliminated, and ventilation can be sufficiently performed. Thereby a drop in ventilation capability can be suppressed, and a pressure increase in the developingchamber 18b can be suppressed, and as a result, toner leakage can be controlled. - The
filter 27 is located in a position more distant from therotation support point 17 of the developingunit 4, compared with the developingroller 22 and thetoner supply roller 20, and is disposed so that the displacement amount in the contact/separation operation is more than that of the developingroller 22 and the like. In other words, thefilter 27 is disposed such that the distance between thefilter 27 and the rotation support point 17 (center of the rotary displacement) (the shortest distance, such as the distance between the right end of thefilter 27 and therotation support point 17 in the portion overlapping with theopening 18g in the cross-section inFIG. 1 ) is longer than the distance between the developingroller 22 and the rotation support point 17 (the longest distance, such as a distance between the point most distant from therotation support point 17 on the peripheral surface of the developingroller 22 and therotation support point 17 in the cross-section inFIG. 1 ). Thereby vibration is more easily generated on thefilter 27 by the contact/separation operation, and the adhering toner can be more effectively separated. - Concerning the timing of the developing contact/separation in this example, the developing contact operation is performed during prior rotation, before forming the image, and the developing separation operation is performed during the post-rotation, after forming the image. In other words, the developing
unit 4 is in the developing contact state while the image forming operation is performed. And the developingunit 4 is in the developing separation state while the image forming operation is not performed. This means that the filter installation surface and the developer contact surface of thefilter 27 maintain the horizontal state, or at an angle close to the horizontal state while the image forming operation is not performed. When the developing contact state is maintained, and the post-rotation operation is not started for a long time, such as in the case of continuous printing, printing is force ended every 500 prints, and the post-rotation is performed. Then, print operation is resumed again. In this example, continuous printing is interrupted every 500 prints, and the post-rotation operation is executed to perform the developing contact/separation operation, but the present invention is not limited to this. It is desirable to set the number of prints at which printing is interrupted in accordance with the configuration of the developing apparatus. Further, in this example, continuous printing is forcibly interrupted at every predetermined number of prints, and the post-rotation operation is performed so as to perform the developing contact/separation operation, but the present invention is not limited to this. For example, if the drive instruction to the developing apparatus is interrupted and the developing contact/separation operation is repeated in a state of stopping the supply of toner, a better effect to separate toner is obtained. - The following experiments were performed to confirm the effect of suppressing toner leakage according to this example. 1. Developing Separation Amount and Optimum Value of Angle of Filter
- The position of the developing unit and the position of the filter member (angle with respect to vertical direction) to suppress toner leakage was verified while changing the developing separation amount by using this example and Comparative Examples 1 to 3. In concrete terms, the developing separation amount is zero in Comparative Example 1, and is increased respectively by 5 mm in the sequence of Comparative Example 2, Comparative Example 3 and this example. Except for this difference, the configuration of the process cartridge and the general configuration of the image forming apparatus according to Comparative Example 1, Comparative Example 2 and Comparative Example 3 are the same as this example.
- Further, in order to evaluate whether toner leakage can be prevented, a continuous printing durability test was performed for 60K prints under a high temperature and high humidity environment (temperature: 30°C; humidity: 80%), in which the degree of agglomeration of toner is low and the filter easily clogs. For this continuous printing durability test, a horizontal line, of which ratio to the image is 1%, is printed as a recording image, and 400 g of toner is filled. At every 10K prints the presence of leaked toner collected on the developer control member was visually checked.
- Table 1 shows the verification result.
[Table 1] Presence of toner leakage Comparative Example 1 Comparative Example 2 Comparative Example 3 This example Developing contact /separation NO YES YES YES Developing separation amount 0 mm 5 mm 10 mm 15 mm Filter angle 30° 20° 10° 0° 0K prints ○ ○ ○ ○ 10K prints ○ ○ ○ ○ 20K prints ○ ○ ○ ○ 30K prints Δ ○ ○ ○ 40K prints × Δ ○ ○ 50K prints - × Δ ○ 60K prints - - × ○ - Comparative Example 1 will be described first. In the case of Comparative Example 1, the
photosensitive drum 1 and the developingroller 22 are constantly in contact, and a small amount of toner leakage was observed at 30K prints, and extreme toner leakage was generated at 40K prints. In this state, toner clogged and ventilation performance dropped considerably. - Comparative Example 2 will be described next. In Comparative Example 2, a small amount of toner leakage was observed at 40K prints, and extreme toner leakage was generated at 50K prints. Compared with Comparative Example 1, an improvement was observed by 10K prints. This may be because the developing separation amount was set to 5 mm for the developing separation, whereby the angle of the filter member became closer to horizontal by 10° compared with Comparative Example 1, and more toner, collected in the concave portions of the filter, fell, and a drop in ventilation capability was suppressed. However, the target 60K prints was not implemented. Further, Comparative Example 3 will be described next. In the case of Comparative Example 3, a small amount of toner leakage was observed at 50K prints, and extreme toner leakage was generated at 60K prints. This is probably because, just like Comparative Example 2, the filter member became more flat due to the increase in the developing separation amount, thereby more toner, collected in the concave portions of the filter, fell, and a drop in ventilation capability was suppressed. However in this configuration as well, the target 60K prints was not implemented.
- This example will now be described. In this example toner leakage was not generated until 60K prints. This is probably because the filter member became flat, thereby more toner, collected in the concave portions of the filter, fell, and a drop in the ventilation capability was suppressed.
- Next the timing to perform the developing separation was confirmed with respect to the number of prints, so that toner leakage is not generated. In Comparative Example 4, the developing separation is forcibly performed at every 750 prints, and in Comparative Example 5, the developing separation is forcibly performed at every 1000 prints. Except for this difference, the configuration of the process cartridge and the general configuration of the image forming apparatus of Comparative Example 4 and Comparative Example 5 are the same as this example.
- Table 2 shows the presence of toner leakage in this example and in the comparative examples.
[Table 2] Presence of toner leakage Comparative Example 4 Comparative Example 5 This example Developing contact timing 1000 750 500 0K prints ○ ○ ○ 5K prints × ○ ○ 10K prints - Δ ○ 20K prints - × ○ 30K prints - - ○ 40K prints - - ○ 50K prints - - ○ 60K prints - - ○ - First Comparative Example 4 will be described. In the case of Comparative Example 4, the developing separation is executed at every 1000 prints, and extreme toner leakage was generated at 5K prints.
- Next Comparative Example 5 will be described. In the case of Comparative Example 5, the developing separation is executed at every 750 prints, and a small amount of toner leakage was observed at 10K prints. Then extreme toner leakage was generated at 20K prints. Even performing the developing separation every 750 prints was insufficient to suppress toner clogging.
- Now this example will be described. In the case of this example, toner leakage was not generated until 60K prints. Based on this result, the developing separation must be executed at least once every 500 prints.
- According to this example, in the image forming apparatus having high speed and long life, the developing separation amount is set to 15 mm, and the developing contact/separation operation is performed every 500 prints, as described above. According to this example, the angle of the filter member (surface of the second chamber thereof) becomes closer to horizontal, and toner collected in the concave portions of the filter can easily fall by the contact/separation operation. In other words, when toner clogs in the filter member due to lengthy operation, the developing apparatus and the filter member are impacted by the developing contact/separation operation, whereby the toner is more easily separated from the filter member. Hence filter clogging can be suppressed, and a drop in ventilation performance can be prevented, as verified in
Experiment 1 andExperiment 2. As a result, an increase in the internal pressure of the developing chamber can be reduced or suppressed, and toner leakage from the developing unit can be prevented. - According to the present invention, an increase in the internal pressure of the unit in which the developer is stored can be suppressed.
- While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications within the scope of the claims.
Claims (15)
- A unit (4) configured to be detachable from an apparatus main body of an image forming apparatus (100),
the unit (4) comprising:a conveying member (23) for conveying developer (T);a frame (18) that stores the developer (T) and including:a first chamber (18a) that stores the conveying member (23),a second chamber (18b), anda first opening (18c) which connects the first chamber (18a) and the second chamber (18b), and through which the developer (T) conveyed from the first chamber (18a) to the second chamber (18b) is passed, characterized in thatthe frame (18) is provided witha second opening (18g) which connects an interior of the second chamber (18b) and an exterior of the frame (18) in an orthogonal direction that is orthogonal to a direction of a rotation axis line of the conveying member (23),the unit (4) comprises a filter (27) that allows passage of air and restricts passage of the developer (T), and the filter (27) being fixed to the frame (18) so as to cover the second opening (18g),the conveying member (23) is deformable such that the developer (T) is conveyed from the first chamber (18a) to the second chamber (18b) via the first opening (18c) by deformation of the conveying member (23) being released, andthe frame (18) is displaceable with respect to the apparatus main body in a state where the unit (4) is attached to the apparatus main body, such thatthe filter (27) is displaced with respect to the apparatus main body. - The unit (4) according to Claim 1, whereinthe frame (18) is displaceable between a first position and a second position, andthe filter (27) has an exposed surface exposed to the interior of the second chamber (18b), and is disposed so that an angle between the exposed surface and a horizontal surface at the first position is smaller than an angle between the exposed surface and the horizontal surface at the second position.
- The unit (4) according to Claim 2, further comprising a developer bearing member (22) that is rotatably supported by the frame (18), wherein
the developer bearing member (22) is displaced with respect to an image bearing member (1) by displacement of the frame (18). - The unit (4) according to Claim 3, wherein
the frame (18) receives a biasing force from a biasing member (181) disposed between the frame (18) and a second frame (14) which supports the image bearing member (1), so as to displace the frame (18) from a separated position, where the developer bearing member (22) is separated from the image bearing member (1), to a contact position, where the developer bearing member (22) contacts the image bearing member (1). - The unit (4) according to Claim 3 or 4, wherein
when the frame (18) is displaced such that the developer bearing member (22) is displaced with respect to the image bearing member (1), an amount of displacement of the filter (27) is greater than an amount of displacement of the developer bearing member (22). - The unit (4) according to any one of Claims 3 to 5, whereinthe displacement of the frame (18) is rotary displacement, andthe filter (27) is disposed so that a distance between the filter (27) and a center of the rotary displacement is longer than a distance between the developer bearing member (22) and the center of the rotary displacement.
- The unit (4) according to any one of Claims 3 to 6, whereinthe developer bearing member (22) is disposed in the second chamber (18b),the frame (18) has a third opening (18d) to expose a part of the developer bearing member (22) to the exterior of the frame (18), andthe second opening (18g) is located at an upstream side of the third opening (18d) on a conveying path of the developer (T) in the second chamber (18b).
- The unit (4) according to Claim 7, wherein
the second opening (18g) is located above the first opening (18c), the developer bearing member (22), and the third opening (18d). - The unit (4) according to Claim 7 or 8, further comprising end seals (25) which are disposed on both edge portions (18k) of the third opening (18d) in a longitudinal direction of the third opening (18d), and a sealing sheet (24) which is fixed to the frame (18), and contacts the developer bearing member (22) between the end seals (25), whereinthe frame (18) includes a fixed portion (18h) to which the sealing sheet (24) is fixed, and a connection wall (18n) which is connected to the fixed portion (18h), and extends in a direction intersecting a direction, in which the sealing sheet (24) extends, andthe second opening (18g) is disposed in the connection wall (18n).
- The unit (4) according to any one of Claims 6 to 9, wherein
the second opening (18g) is disposed so as to extend from one end to the other end of the developer bearing member (22) in the direction of the rotation axis line. - The unit (4) according to any one of Claims 6 to 10, further comprising a supply member (20), which is disposed in the second chamber (18b), and supplies the developer (T) to the developer bearing member (22) by contacting with the developer bearing member (22).
- The unit (4) according to Claim 11, wherein
when a first line (L1), which connects one end of the first opening (18c) and one end of the second opening (18g), and a second line (L2), which connects the other end of the first opening (18c) and the other end of the second opening (18g), are drawn in the orthogonal direction, at least a part of the supply member (20) is located outside a region between the first line (L1) and the second line (L2). - The unit (4) according to any one of Claims 6 to 12, wherein
the second chamber (18b) is located above the first chamber (18a). - A process cartridge (7) configured to be detachable from an apparatus main body of an image forming apparatus (100),
the process cartridge (7) comprising:the unit (4) according to any one of Claims 1 to 13 that includes a developer bearing member (22); anda second unit (13) including an image bearing member (1), whereinrelative positions of the first unit (4) and the second unit (13) can be changed so that the developer bearing member (22) and the image bearing member (1) can be contacted or separated. - An image forming apparatus (100), comprising:an apparatus main body that includes an image bearing member (1);the unit (4) according to any one of Claims 1 to 13 that includes a developer bearing member (22), and is detachable from the apparatus main body; anda contact/separation mechanism that displaces the unit (4) in the interior of the apparatus main body so that the developer bearing member (22) can be in a contact state where the developer bearing member (22) contacts the image bearing member (1), or in a separated state where the developer bearing member (22) is separated from the image bearing member (1).
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JP2016218761 | 2016-11-09 | ||
JP2017193639A JP7009150B2 (en) | 2016-11-09 | 2017-10-03 | Units, process cartridges and image forming equipment |
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EP3349066B1 true EP3349066B1 (en) | 2021-03-31 |
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EP (1) | EP3349066B1 (en) |
JP (1) | JP7009150B2 (en) |
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JP7206614B2 (en) * | 2018-04-04 | 2023-01-18 | 富士フイルムビジネスイノベーション株式会社 | Developing device and image forming device |
JP7200655B2 (en) * | 2018-12-19 | 2023-01-10 | 富士フイルムビジネスイノベーション株式会社 | Developing device, developing unit and image forming apparatus |
CN114430812B (en) | 2019-09-17 | 2024-03-12 | 佳能株式会社 | Cartridge and image forming apparatus |
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JPS5419319A (en) | 1977-07-14 | 1979-02-14 | Fujitsu Ltd | Synchronous protection circuit |
US4583112A (en) * | 1984-10-29 | 1986-04-15 | Xerox Corporation | Venting system for the developer housing of an electrostatic copying machine |
JPH08146745A (en) * | 1994-11-21 | 1996-06-07 | Canon Inc | Developer storing container and process cartridge |
JP2003270939A (en) | 2002-03-18 | 2003-09-25 | Seiko Epson Corp | Developing device, image forming apparatus and computer system |
JP4674798B2 (en) | 2004-05-06 | 2011-04-20 | 株式会社リコー | Developing device, process cartridge, and image forming apparatus |
JP4628856B2 (en) | 2005-04-28 | 2011-02-09 | 株式会社リコー | Image forming apparatus, developing device, process cartridge |
JP4790676B2 (en) | 2007-08-02 | 2011-10-12 | 株式会社リコー | Developing device, process cartridge, and image forming apparatus |
JP5327573B2 (en) | 2007-10-31 | 2013-10-30 | 株式会社リコー | Developing device, process unit, and image forming apparatus |
JP5020109B2 (en) | 2008-01-24 | 2012-09-05 | 株式会社リコー | Developing device, process cartridge, image forming apparatus, color image forming apparatus |
JP5111238B2 (en) * | 2008-05-27 | 2013-01-09 | キヤノン株式会社 | Process cartridge |
JP5418895B2 (en) * | 2009-03-13 | 2014-02-19 | 株式会社リコー | Developing device, and image forming apparatus and process cartridge provided with the same |
JP5317935B2 (en) | 2009-11-26 | 2013-10-16 | キヤノン株式会社 | Developing device and process cartridge |
JP6512864B2 (en) * | 2015-02-27 | 2019-05-15 | キヤノン株式会社 | Cartridge, process cartridge, image forming apparatus |
-
2017
- 2017-10-03 JP JP2017193639A patent/JP7009150B2/en active Active
- 2017-11-01 KR KR1020170144483A patent/KR102285652B1/en active IP Right Grant
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KR20180052092A (en) | 2018-05-17 |
JP7009150B2 (en) | 2022-01-25 |
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