EP3432076B1 - Method of fixing regulating blade and development device - Google Patents
Method of fixing regulating blade and development device Download PDFInfo
- Publication number
- EP3432076B1 EP3432076B1 EP18174443.4A EP18174443A EP3432076B1 EP 3432076 B1 EP3432076 B1 EP 3432076B1 EP 18174443 A EP18174443 A EP 18174443A EP 3432076 B1 EP3432076 B1 EP 3432076B1
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- Prior art keywords
- doctor blade
- gap
- blade
- regulating blade
- frame member
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Images
Classifications
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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
- G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
- G03G15/0812—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller characterised by the developer regulating means, e.g. structure of doctor blade
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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
- G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
- G03G15/081—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller characterised by the developer handling means after the supply and before the regulating, e.g. means for preventing developer blocking
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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
- G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
- G03G15/0865—Arrangements for supplying new developer
Definitions
- the present invention generally relates to a method of fixing a regulating blade made of, for example, resin. It also related to a development device equipped with the regulating blade made of resin, for example.
- a development device is equipped with a regulating blade (a developer regulating member) which has a coated amount regulating surface (a regulating portion) used to regulate the amount (a developer coated amount) of a developer borne (e.g. carried) on the surface of a developer bearing member, which bears (e.g. carries) a developer used to develop an electrostatic latent image formed on an image bearing member.
- the regulating blade is arranged to face the developer bearing member over the longitudinal direction of the developer bearing member via a predetermined gap between the regulating blade and the surface of the developer bearing member (the gap being hereinafter referred to as an "SB gap G").
- the SB gap G is the shortest distance between the surface of the developer bearing member, which is supported by a frame member of a developer container (a development frame member), and the coated amount regulating surface of the regulating blade, which is attached to the frame member of the developer container. Adjusting the size of the SB gap G enables adjusting the amount of a developer to be conveyed to a development region at which the developer bearing member faces the image bearing member.
- a development device discussed in Japanese Patent Application Laid-Open No. 2014-197175 includes a developer regulating member made of resin, which is molded with resin, and a frame member of a developer container made of resin, which is molded with resin.
- the SB gap G tends to become more likely to vary in the longitudinal direction of the developer bearing member. If the SB gap G varies in the longitudinal direction of the developer bearing member, variations in the longitudinal direction of the developer bearing member may occur in the amount of a developer to be borne on the surface of the developer bearing member.
- the SB gap G be within a predetermined range over the longitudinal direction of the developer bearing member in a state that the regulating blade is fixed to a blade attaching portion of the development frame member, irrespective of the straightness of the coated amount regulating surface of the regulating blade.
- aspects of the present invention are preferably directed to providing a method of fixing a regulating blade to a development device, particularly in cases where the regulating blade is made of resin and has a regulating portion which is not straight.
- a gap between a developer bearing member and the regulating portion is formed.
- the gap may be within a predetermined range over the longitudinal direction of the developer bearing member.
- the gap may be formed after the regulating blade is fixed to a blade attaching portion of a development frame member.
- the invention provides a method of fixing a development frame member as specified in any one of claims 1 to 6.
- the invention provides a method of attaching a regulating blade made of resin to an attaching portion of a development frame member made of resin, the attaching portion being used to attach the regulating blade, the regulating blade being (i) arranged in non-contact with a developer bearing member that is arranged to carry a developer for developing an electrostatic latent image formed on an image bearing member, (ii) arranged to face the developer bearing member, and (iii) configured to regulate an amount of the developer to be carried on the developer bearing member, characterized in that the method of attaching the regulating blade comprising:
- a development device as specified in claims 7 to 10.
- a development device comprising:
- the developer bearing member may be a rotatable developing sleeve as described herein (e.g. item 70 in Fig. 2 ).
- the image bearing member may be a photosensitive drum as described herein (e.g. item 1 in Fig. 1 ).
- the regulating blade is deformable and may be a doctor blade as described herein (e.g. item 36 in Fig. 2 ).
- the development device is preferably part of an image forming apparatus. The regulating blade is ideally separated from the developer bearing member by the gap.
- the image forming apparatus 60 includes four image forming units 600 arranged from the upstream side to the downstream side along an endless intermediate transfer belt (ITB) 61, serving as an intermediate transfer member, and along the rotational direction of the intermediate transfer belt 61 (the direction of arrow C in Fig. 1 ).
- the image forming units 600 form images of the respective colors, yellow (Y), magenta (M), cyan (C), and black (Bk).
- Each image forming unit 600 includes a rotatable photosensitive drum 1, which serves as an image bearing member. Moreover, each image forming unit 600 further includes a charging roller 2 serving as a charging unit, a development device 3 serving as a development unit, a primary transfer roller 4 serving as a primary transfer unit, and a photosensitive member cleaner 5 serving as a photosensitive member cleaning unit, which are arranged along the rotational direction of the photosensitive drum 1.
- Each development device 3 is detachably attached to the image forming apparatus 60.
- Each development device 3 includes a developer container 50, which contains a two-component developer (hereinafter referred to simply as a "developer") including non-magnetic toner (hereinafter referred to simply as "toner”) and magnetic carrier.
- developer a two-component developer
- toner non-magnetic toner
- toner cartridges in which toners of respective colors, Y, M, C, and Bk, are respectively contained are detachably attached to the image forming apparatus 60. Toners of respective colors, Y, M, C, and Bk, are supplied to the respective developer containers 50 via toner conveyance paths.
- details of the development device 3 are described below with reference to Fig. 2 to Fig. 4
- details of the developer container 50 are described below with reference to Fig. 5 .
- the intermediate transfer belt 61 is supported by a tension roller 6, a driven roller 7a, a primary transfer roller 4, a driven roller 7b, and a secondary transfer inner roller 66 to extend in a tensioned state, and is driven to be conveyed in the direction of arrow C in Fig. 1 .
- the secondary transfer inner roller 66 also serves as a driving roller used to drive the intermediate transfer belt 61. In conjunction with rotation of the secondary transfer inner roller 66, the intermediate transfer belt 61 rotates in the direction of arrow C in Fig. 1 .
- the intermediate transfer belt 61 is pressed by the primary transfer roller 4 from the back side of the intermediate transfer belt 61. Moreover, the intermediate transfer belt 61 abutting on the photosensitive drum 1 forms a primary transfer nip portion serving as a primary transfer portion between the photosensitive drum 1 and the intermediate transfer belt 61.
- An intermediate transfer member cleaner 8 serving as a belt cleaning unit abuts on a position opposite to the tension roller 6 via the intermediate transfer belt 61.
- a secondary transfer outer roller 67 serving as a secondary transfer unit is arranged at a position opposite to the secondary transfer inner roller 66 via the intermediate transfer belt 61.
- the intermediate transfer belt 61 is sandwiched between the secondary transfer inner roller 66 and the secondary transfer outer roller 67.
- a secondary transfer nip portion serving as a secondary transfer portion is formed between the secondary transfer outer roller 67 and the intermediate transfer belt 61.
- imparting a predetermined pressure and a predetermined transfer bias electrostatic load bias
- Sheets S are stored in the state of being stacked in a sheet storing portion 62 (for example, a feed cassette or a feed deck) .
- a feed unit 63 feeds a sheet S in conformity with image forming timing with use of, for example, a friction separation method using, for example, a feed roller.
- the sheet S fed by the feed unit 63 is conveyed to a registration roller 65, which is located on the way of a conveyance path 64. After being subjected to skew correction and timing correction at the registration roller 65, the sheet S is conveyed to the secondary transfer nip portion. At the secondary transfer nip portion, the sheet S and the toner image coincide in timing with each other, so that secondary transfer is performed.
- a fixing device 9 is arranged at the more downstream side in the conveyance direction of the sheet S than the secondary transfer nip portion. Imparting a predetermined pressure and a predetermined amount of heat from the fixing device 9 to the sheet S conveyed to the fixing device 9 causes the toner image to be fused and fixed onto the surface of the sheet S.
- the sheet S with an image fixed thereto in this way is directly discharged to a discharge tray 601 according to the forward rotation of a discharge roller 69.
- the discharge roller 69 is rotated backward. With this, the leading and trailing edges of the sheet S are switched, so that the sheet S is conveyed to a two-sided conveyance path 603. After that, in conformity with next image forming timing, the sheet S is re-conveyed by a re-feed roller 604 to the conveyance path 64.
- the photosensitive drum 1 is driven to rotate by a motor.
- the charging roller 2 uniformly charges the surface of the photosensitive drum 1, which is being driven to rotate, in advance.
- An exposure device 68 forms an electrostatic latent image on the surface of the photosensitive drum 1 charged by the charging roller 2, based on a signal of image information input to the image forming apparatus 60.
- the photosensitive drum 1 allows a plurality of sizes of electrostatic latent images to be formed thereon.
- the development device 3 includes a rotatable developing sleeve 70, which serves a developer bearing member that bears (e.g. carries) a developer.
- the development device 3 develops an electrostatic latent image formed on the surface of the photosensitive drum 1 with use of a developer borne (e.g. carried) on the surface of the developing sleeve 70. With this, toner adheres to an exposure portion on the surface of the photosensitive drum 1, so that a visible image appears thereon.
- a transfer bias (electrostatic load bias) is imparted to the primary transfer roller 4, so that a toner image formed on the surface of the photosensitive drum 1 is transferred onto the intermediate transfer belt 61. Toner slightly remaining on the surface of the photosensitive drum 1 after primary transfer (transfer residual toner) is recovered by the photosensitive member cleaner 5, and is then re-prepared for a next image formation process.
- Image formation processes for respective colors which are parallelized by the image forming units 600 for respective colors, Y, M, C, and Bk, are performed at timing in which a next toner image is sequentially superposed on a toner image for the upstream color primarily transferred on the intermediate transfer belt 61.
- a full-color toner image is formed on the intermediate transfer belt 61, so that the toner image is conveyed to the secondary transfer nip portion.
- a transfer bias is imparted to the secondary transfer outer roller 67, so that the toner image formed on the intermediate transfer belt 61 is transferred to the sheet S conveyed to the secondary transfer nip portion.
- Toner slightly remaining on the intermediate transfer belt 61 after the sheet S passes through the secondary transfer nip portion (transfer residual toner) is recovered by the intermediate transfer member cleaner 8.
- the fixing device 9 fixes the toner image transferred onto the sheet S.
- the sheet (recording medium) S subjected to fixing processing by the fixing device 9 is discharged to the discharge tray 601.
- Fig. 4 is a sectional view of the development device 3 illustrating a cross-section H in Fig. 2 .
- the development device 3 includes a developer container 50 configured with a development frame member made of resin, which is molded with resin (hereinafter referred to simply as a "development frame member 30"), and a cover frame member made of resin, which is molded with resin (hereinafter referred to simply as a "cover frame member 40"), which is formed separately from the development frame member 30.
- Fig. 2 and Fig. 4 illustrate a state in which the cover frame member 40 is attached to the development frame member 30, and
- Fig. 3 illustrates a state in which the cover frame member 40 is not attached to the development frame member 30. Furthermore, details of the configuration of the development frame member 30 (single body) are described below with reference to Fig. 5 .
- the developer container 50 is provided with an aperture at a position equivalent to a development region in which the developing sleeve 70 faces the photosensitive drum 1.
- the developing sleeve 70 is arranged to be rotatable relative to the developer container 50 in such a manner that a part of the developing sleeve 70 is exposed on the aperture of the developer container 50.
- a bearing 71 serving as a bearing member is provided at each of both end portions of the developing sleeve 70.
- the inside of the developer container 50 is sectioned by a partition wall 38, which extends in vertical direction, into a development chamber 31 serving as a first chamber and an agitation chamber 32 serving as a second chamber.
- the development chamber 31 and the agitation chamber 32 are connected with each other at both ends in the longitudinal direction thereof via communication portions 39 provided at two locations of the partition wall 38. Therefore, a developer is allowed to be transmitted between the development chamber 31 and the agitation chamber 32 via the communication portions 39.
- the development chamber 31 and the agitation chamber 32 are arranged horizontally side by side with respect to the horizontal direction.
- a magnet roll having a plurality of magnetic poles along the rotational direction of the developing sleeve 70 and serving as a magnetic field generation unit that generates a magnetic field for causing the surface of the developing sleeve 70 to bear (e.g. carry) a developer thereon is fixedly arranged inside the developing sleeve 70.
- a developer in the development chamber 31 is drawn up under the influence of a magnetic field caused by the magnetic poles of the magnet roll, and is thus supplied to the developing sleeve 70. Since a developer is supplied from the development chamber 31 to the developing sleeve 70 in this way, the development chamber 31 is also referred to as a "supply chamber".
- a first conveyance screw 33 which serves as a conveyance unit that agitates a developer in the development chamber 31 and conveys the developer, is arranged opposite the developing sleeve 70.
- the first conveyance screw 33 includes a rotation shaft 33a, which serves as a rotatable shaft portion, and a spiral blade portion 33b, which serves as a developer conveyance portion, provided along the outer circumference of the rotation shaft 33a, and is supported in such a way as to be rotatable relative to the developer container 50.
- a bearing member is provided at each of both end portions of the rotation shaft 33a.
- a second conveyance screw 34 which serves as a conveyance unit that agitates a developer in the agitation chamber 32 and conveys the developer in a direction opposite to that of the first conveyance screw 33, is arranged.
- the second conveyance screw 34 includes a rotation shaft 34a, which serves as a rotatable shaft portion, and a spiral blade portion 34b, which serves as a developer conveyance portion, provided along the outer circumference of the rotation shaft 34a, and is supported in such a way as to be rotatable relative to the developer container 50.
- a bearing member is provided at each of both end portions of the rotation shaft 34a. Then, when the first conveyance screw 33 and the second conveyance screw 34 are driven to rotate, a developer is caused to circulate between the development chamber 31 and the agitation chamber 32 via the communication portions 39.
- a regulating blade which serves as a developer regulating member that regulates the amount of a developer borne on the surface of the developing sleeve 70 (also referred to as a "developer coated amount”) (hereinafter referred to as a “doctor blade 36”), is attached to the developer container 50 while being arranged opposite the surface of the developing sleeve 70 in a non-contact manner therewith.
- the doctor blade 36 has a coated amount regulating surface 36r (i.e. regulating portion or regulating surface), which serves as a regulating portion used to regulate the amount of a developer borne on the surface of the developing sleeve 70.
- the doctor blade 36 is a doctor blade made of resin, which is molded with resin. Furthermore, a configuration of the doctor blade 36 (single body) is described below with reference to Fig. 6 .
- the doctor blade 36 is arranged opposite the developing sleeve 70 via a predetermined gap (hereinafter referred to as an "SB gap G") between the doctor blade 36 and the developing sleeve 70 over the longitudinal direction of the developing sleeve 70 (i.e., a direction parallel to the direction of a rotational axis of the developing sleeve 70). That is, for example, the predetermined gap separates the doctor blade 36 and the developing sleeve 70. Preferably, the predetermined gap separates the doctor blade 36 from the developing sleeve 70 by a fixed amount along the length of the doctor blade 36.
- SB gap G a predetermined gap
- the length axis of the doctor blade 36 is preferably parallel with the length of the axis of the developing sleeve 70.
- the developing sleeve 70 is preferably arranged to rotate about its length axis.
- the SB gap G preferably refers to the shortest distance between a region corresponding to a maximum image region which the developing sleeve 70 is able to form on the surface of the photosensitive drum 1 (in other words, a maximum image region of the developing sleeve 70) and a region of the doctor blade 36 corresponding to the maximum image region (in other words, a maximum image region of the doctor blade 36).
- the maximum image region is assumed to refer to an image region corresponding to the largest size (for example, A3 size) among a plurality of sizes of electrostatic latent images able to be formed on the photosensitive drum 1.
- the maximum image region is assumed to instead refer to an image region corresponding to only one size of image able to be formed on the photosensitive drum 1.
- the doctor blade 36 may be arranged approximately/substantially opposite the peak position of a magnetic flux density of magnetic poles of the magnet roll.
- a developer supplied to the developing sleeve 70 is affected by a magnetic field caused by the magnetic poles of the magnet roll.
- a developer regulated and scraped by the doctor blade 36 tends to stagnate (e.g. decay) at the upstream portion of the SB gap G.
- a developer stagnation is formed at the more upstream side in the rotational direction of the developing sleeve 70 than the doctor blade 36.
- the amount of developer at the ends of the development sleeve 70 may be reduced (as compared to the center of the development sleeve 70) as a result of the doctor blade scraping the development sleeve 70.
- the doctor blade scrapes the development sleeve 70 to regulate the amount of developer on it. Consequently, a partial developer of the developer stagnation is conveyed in such a way as to pass through the SB gap G according to the rotation of the developing sleeve 70.
- the layer thickness of a developer passing through the SB gap G is regulated by the coated amount regulating surface 36r of the doctor blade 36. In this way, a thin layer of developer is formed on the surface of the developing sleeve 70.
- a size of the SB gap G targeted to adjust the size of the SB gap G is set to about 300 micrometers ( ⁇ m).
- the developer conveyed to the development region is magnetically lifted at the development region, so that a magnetic brush is formed.
- the magnetic brush contacting the photosensitive drum 1 causes toner contained in the developer to be supplied to the photosensitive drum 1.
- an electrostatic latent image formed on the surface of the photosensitive drum 1 is developed as a toner image.
- a developer on the surface of the developing sleeve 70 remaining after passing the development region and supplying toner to the photosensitive drum 1 (hereinafter referred to as a "developer after development process”) is peeled from the surface of the developing sleeve 70 by a repulsive magnetic field formed between magnetic poles of the same polarity of the magnet roll.
- the developer after development process peeled from the surface of the developing sleeve 70 falls in the development chamber 31, thus being recovered into the development chamber 31.
- the development frame member 30 is provided with a developer guide portion 35 for guiding a developer in such a manner that the developer is conveyed toward the SB gap G.
- the developer guide portion 35 and the development frame member 30 are configured to be integrally formed, and the developer guide portion 35 and the doctor blade 36 are configured to be separately formed.
- the developer guide portion 35 is formed inside the development frame member 30, and is arranged at the more upstream side in the rotational direction (i.e. in the anticlockwise direction as viewed in Fig. 4 ) of the developing sleeve 70 than the coated amount regulating surface 36r of the doctor blade 36.
- the flow of a developer is stabilized by the developer guide portion 35 to make adjustment to obtain a predetermined developer density, so that the weight of a developer at a position in which the coated amount regulating surface 36r of the doctor blade 36 is in most proximity to the surface of the developing sleeve 70 can be defined.
- the cover frame member 40 is formed separately from the development frame member 30 and is attached to the development frame member 30. Additionally, the cover frame member 40 covers a part of the aperture of the development frame member 30 in such a manner that a part of the outer circumferential surface of the developing sleeve 70 is covered over the entirety in the longitudinal direction of the developing sleeve 70. At this time, the cover frame member 40 covers a part of the aperture of the development frame member 30 in such a manner that a development region facing the photosensitive drum 1 of the developing sleeve 70 is exposed.
- the method of fixing the cover frame member 40 to the development frame member 30 can be any method, such as screw fastening, snap fit, adhesion, or welding.
- Fig. 5 illustrates a state in which the cover frame member 40 is not attached to the development frame member 30.
- the development frame member 30 includes the development chamber 31 and the agitation chamber 32, which is separated from the development chamber 31 via the partition wall 38 (see Fig. 4 ).
- the partition wall 38 is molded with resin, and can be configured to be formed separately from the development frame member 30 or can be formed integrally with the development frame member 30.
- the development frame member 30 has sleeve supporting portions 42 configured to support the developing sleeve 70 in such a way as to allow the developing sleeve 70 to rotate by supporting bearings 71 respectively provided at both end portions of the developing sleeve 70 (see Figs. 3 , 4 and 5 ). Moreover, the development frame member 30 has a blade attaching portion 41 (which is formed integrally with the sleeve supporting portions 42) to which the doctor blade 36 is attached. Fig. 5 illustrates a virtual state in which the doctor blade 36 floats above the blade attaching portion 41.
- an adhesive A applied to a blade attaching surface 41s of the blade attaching portion 41 becomes hardened, so that the doctor blade 36 is fixed to the blade attaching portion 41 (See Fig. 4 ). Details of the method of fixing the doctor blade 36 to the blade attaching portion 41 are described below with reference to Fig. 9 and subsequent figures.
- the width of the sheet S on which an image is to be formed for example, the width of the sheet S being A3 size
- the area of a coated amount regulating surface corresponding to the maximum image region able to be formed on the surface of the photosensitive drum 1 becomes larger, so that the length in the longitudinal direction of a doctor blade becomes larger.
- the length of the doctor blade (note the length extends along the longitudinal axis of the doctor blade) is large, and the doctor blade is molded with resin, it is difficult to ensure the straightness/uniformity of the blade with a coated amount regulating surface provided for the doctor blade made of resin, which is molded with resin. This is because, when a doctor blade the length in the longitudinal direction of which is large is molded with resin, variations are likely to occur in ratios in which thermally-expanded resin thermally contracts.
- the straightness of a coated amount regulating surface is represented by the absolute value of a difference between the maximum value and minimum value of the outer shape of a coated amount regulating surface based on a predetermined location on the coated amount regulating surface in the longitudinal direction of the coated amount regulating surface. For example, suppose that a central portion of the coated amount regulating surface in the longitudinal direction of the coated amount regulating surface is set as the origin, a predetermined straight line passing through the origin is set as the X-axis, and a straight line drawn from the origin in a direction perpendicular to the X-axis is set as the Y-axis. In this orthogonal coordinate system, the straightness of a coated amount regulating surface is represented by the absolute value of a difference between the maximum value and minimum value of the Y-coordinate of the outer shape of the coated amount regulating surface.
- the straightness of a coated amount regulating surface is approximately 300 ⁇ m to 500 ⁇ m.
- the straightness of a coated amount regulating surface is approximately 100 ⁇ m to 200 ⁇ m.
- the SB gap is more likely to vary along the longitudinal direction (i.e. along the longitudinal axis) of the developer bearing member due to the straightness of a coated amount regulating surface - e.g. the size of the SB gap separating the doctor blade from the development sleeve may vary along the length (i.e. along the longitudinal axis) of the development sleeve/doctor blade due to variations/non-uniformities in the straightness of the doctor blade.
- unevenness in the straightness of the regulating surface of the doctor blade can cause variations in the size of the SB gap. If the SB gap varies in/along the longitudinal direction/axis of a developer bearing member, unevenness may occur in the amount of a developer to be borne on the surface of the developer bearing member in the longitudinal direction of the developer bearing member.
- the SB gap G is configured to be within a predetermined range over the longitudinal direction/axis of the developing sleeve 70.
- the tolerance of the SB gap G (in other words, a tolerance of the SB gap G relative to a target value) is set to ⁇ 10% or less, so that the SB gap G falls within a predetermined range over the longitudinal direction of the developing sleeve 70.
- a method described as follows is used to determine whether the SB gap G is within a predetermined range over the longitudinal direction of the developing sleeve 70. Furthermore, details of a method of measuring the SB gap G (calculation method) are described below with reference to Fig. 11 .
- an area corresponding to the maximum image region of the doctor blade 36 is divided into four or more locations at even intervals, and the SB gap G is measured at five or more locations in each of the divided locations of the doctor blade 36 (in this regard, including both end portions and a central portion of the area corresponding to the maximum image region of the doctor blade 36). Then, the maximum value of the SB gap G, the minimum value of the SB gap G, and the median value of the SB gap G are extracted from samples of measured values of the SB gap G measured at five or more locations.
- the tolerance of the SB gap G is assumed to be ⁇ 10% or less and the SB gap G is assumed to satisfy being within a predetermined range over the longitudinal direction of the developing sleeve 70.
- the median value of the SB gap G is 300 ⁇ m based on samples of measured values of the SB gap G measured at five or more locations, if the maximum value of the SB gap G is 330 ⁇ m or less and the minimum value of the SB gap G is 270 ⁇ m or more, then it is acceptable. In other words, in this case, it is meant that the adjustment value of the SB gap G is 300 ⁇ m ⁇ 30 ⁇ m and the allowable tolerance of the SB gap G is up to 60 ⁇ m.
- the SB gap G is desired to be within a predetermined range over the longitudinal direction (i.e. over the longitudinal axis or length) of a developer bearing member in a state that the doctor blade is fixed to the blade attaching portion of the development frame member, regardless of the straightness of a coated amount regulating surface.
- the first exemplary embodiment employs a configuration described below in such a manner that, even when a doctor blade made of resin, in which the accuracy of the straightness of a coated amount regulating surface is low, is used, a gap between the developer bearing member and the doctor blade is made to be within a predetermined range over the longitudinal direction (i.e. over the longitudinal axis or length) of the developer bearing member in a state that the doctor blade is fixed to the blade attaching portion of the development frame member. Details thereof are described as follows.
- doctor blade 36 single body
- developer pressure the pressure of a developer (hereinafter referred to as "developer pressure"), which occurs due to the flow of the developer, is imparted to the doctor blade 36.
- developer pressure the pressure of a developer
- the doctor blade 36 is more likely to become deformed, so that the size of the SB gap G is more likely to vary.
- the developer pressure is imparted in the widthwise direction of the doctor blade 36 (i.e. the direction of arrow M in Fig. 6 , which is perpendicular to the length of the doctor blade 36). Therefore, to prevent or reduce variations in the size of the SB gap G in the process of an image forming operation (development operation), it is desirable that the rigidity in the widthwise direction of the doctor blade 36 be increased to strengthen the doctor blade 36 against deformation in the widthwise direction thereof.
- the shape of the doctor blade 36 is made platelike from the viewpoint of mass productivity and cost. Moreover, as illustrated in Fig. 6 , in the first exemplary embodiment, the cross-sectional area of a side surface 36t of the doctor blade 36 is made small, and, additionally, the length t2 in the thickness direction of the doctor blade 36 is made smaller than the length t1 in the widthwise direction of the doctor blade 36 (i.e. the thickness t2 of the doctor blade 36 is made smaller than the width t1 of the doctor blade 36). With this, the doctor blade 36 (single body) is configured to easily deform in a direction (the direction of arrow M in Fig.
- the first exemplary embodiment employs a method of fixing the doctor blade 36 to the blade attaching portion 41 of the development frame member 30 in a state in which at least a part of the doctor blade 36 is warped in/along the direction of arrow M in Fig. 6 . Furthermore, details of the method of fixing the doctor blade 36 to the blade attaching portion 41 of the development frame member 30 (hereinafter referred to as a "fixation method for the doctor blade 36") are described below with reference to Fig. 9 and subsequent figures.
- the rigidity of the doctor blade 36 is described with reference to the schematic view of Fig. 7 .
- the rigidity of the doctor blade 36 is measured in a state in which the doctor blade 36 is not fixed to the blade attaching portion 41 of the development frame member 30.
- a concentrated load F1 is imparted in the widthwise direction of the doctor blade 36 to a central portion 36z of the doctor blade 36 as viewed in the longitudinal direction of the doctor blade 36.
- the rigidity of the doctor blade 36 is measured based on the amount of warp in the widthwise direction of the doctor blade 36 at the central portion 36z of the doctor blade 36.
- a concentrated load F1 of 300 gram-force (gf) is imparted in the widthwise direction of the doctor blade 36 to the central portion 36z of the doctor blade 36 as viewed in the longitudinal direction of the doctor blade 36 (i.e. load F1 is applied to the central portion 36z of the doctor blade 36 and the central portion 36z is located in the middle of the doctor blade's length).
- load F1 is applied to the central portion 36z of the doctor blade 36 and the central portion 36z is located in the middle of the doctor blade's length.
- the amount of warp in the widthwise direction of the doctor blade 36 at the central portion 36z of the doctor blade 36 is 700 ⁇ m or more.
- the amount of deformation of the central portion 36z of the doctor blade 36 on the cross-section is 5 ⁇ m or less. It will be noted that the amount of warp/deformation is preferably determined relative to when no force is applied to the doctor blade 36.
- the rigidity of the development frame member 30 is described with reference to the schematic view of Fig. 8 .
- the rigidity of the development frame member 30 is measured in a state in which the doctor blade 36 is not fixed to the blade attaching portion 41 of the development frame member 30.
- a concentrated load F1 is imparted in the widthwise direction of the blade attaching portion 41 to a central portion 41z of the blade attaching portion 41 as viewed in the longitudinal direction of the blade attaching portion 41.
- the rigidity of the development frame member 30 is measured based on the amount of warp in the widthwise direction of the blade attaching portion 41 at the central portion 41z of the blade attaching portion 41.
- the amount of warp in the widthwise direction of the blade attaching portion 41 at the central portion 41z of the blade attaching portion 41 is 60 ⁇ m or less.
- the concentrated load F1 of the same magnitude is imparted to each of the central portion 36z of the doctor blade 36 and the central portion 41z of the blade attaching portion 41 of the development frame member 30.
- the amount of warp of the central portion 36z of the doctor blade 36 is 10 times or more the amount of warp of the central portion 41z of the blade attaching portion 41.
- the magnitude of the rigidity of the development frame member 30 (single body) is at least 10 times larger than the magnitude of the rigidity of the doctor blade 36 (single body).
- the rigidity of the development frame member 30 becomes more dominant than the rigidity of the doctor blade 36.
- the magnitude of the rigidity of the development frame member 30 (single body) is larger than the magnitude of the rigidity of the cover frame member 40 (single body). Therefore, in a state in which the cover frame member 40 is attached to the development frame member 30 so that the cover frame member 40 is fixed to the development frame member 30, the rigidity of the development frame member 30 becomes more dominant than the rigidity of the cover frame member 40.
- An external apparatus (hereinafter referred to simply as an "apparatus 100") performs each of steps of the fixation method for the doctor blade 36 described as follows.
- the apparatus 100 detects the outer shape of the coated amount regulating surface 36r of the doctor blade 36.
- the apparatus 100 recognizes the straightness of the coated amount regulating surface 36r based on a central portion of the coated amount regulating surface 36r (a front edge portion 36e3 of the doctor blade 36) with regard to the outer shape of the coated amount regulating surface 36r in the longitudinal direction of the coated amount regulating surface 36r.
- a doctor blade made of resin compatible with A3 size manufactured with the accuracy of a general resin product is used. Therefore, the apparatus 100 recognizes that the straightness of the coated amount regulating surface 36r is approximately 300 ⁇ m to 500 ⁇ m.
- the apparatus 100 warps at least a part of the area corresponding to the maximum image region of the doctor blade 36 with a force imparted to the doctor blade 36. Then, the apparatus 100 corrects the straightness of the coated amount regulating surface 36r to 50 ⁇ m or less (hereinafter referred to as a "warping step").
- the apparatus 100 determines a position at which to fix the doctor blade 36, at least a part of the area corresponding to the maximum image region of which has been warped in the warping step, to the blade attaching portion 41 of the development frame member 30 so as to cause the SB gap G to fall within a predetermined range (hereinafter referred to as a "positioning step").
- the apparatus 100 fixes a part of the area corresponding to the maximum image region of the doctor blade 36 at a predetermined position of the blade attaching portion 41 determined in the positioning step (hereinafter referred to as a "fixation step").
- the apparatus 100 includes a placement board 103 on which to place the doctor blade 36 (single body). Moreover, the apparatus 100 further includes fingers 101 (101p1 to 101p5) provided at five locations to grasp the respective grab portions 37 (37P1 to 37p5) provided at five locations in the area corresponding to the maximum image region of the doctor blade 36. Each of the fingers 101 (101p1 to 101p5) is independently movable along the direction J in Fig. 9 , and is able to move forward and move backward with respect to the direction J in Fig. 9 .
- the apparatus 100 further includes cameras 102 (102p1 to 102p5) provided at five locations to measure the respective positions of front edge portions 36e (36e1 to 36e5) provided at five locations included in the coated amount regulating surface 36r of the doctor blade 36.
- Each of the cameras 102 (102p1 to 102p5) is arranged along a direction toward a corresponding one of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36 (the direction of arrow F in Fig. 9 ). Then, the cameras 102 (102p1 to 102p5) detect the outer shape of the coated amount regulating surface 36r of the doctor blade 36 by measuring the positions of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36.
- the apparatus 100 recognizes the straightness of the coated amount regulating surface 36r based on the central portion of the coated amount regulating surface 36r (the front edge portion 36e3 of the doctor blade 36) with regard to the outer shape of the coated amount regulating surface 36r in the longitudinal direction of the coated amount regulating surface 36r. Furthermore, while an example in which the measurement of the positions of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36 is performed by the cameras 102 (102p1 to 102p5) is hereinafter described, a modification example in which the measurement is performed by non-contact sensors can be employed.
- the doctor blade 36 is manufactured with the precision of a general resin product.
- the straightness of a coated amount regulating surface is approximately 300 ⁇ m to 500 ⁇ m.
- the doctor blade 36 is a doctor blade made of resin compatible with A3 size which is manufactured with the precision of a general resin product.
- the doctor blade 36 in a state in which the doctor blade 36 is placed on the placement board 103, when the positions of the front edge portions 36e (36e1 to 36e5) provided at five locations of the doctor blade 36 are measured by the cameras 102 (102p1 to 102p5), a difference of approximately 300 ⁇ m to 500 ⁇ m would be detected.
- the tolerance of the SB gap G is set to ⁇ 10% or less so as to prevent or reduce unevenness in the amount of a developer to be borne on the surface of the developing sleeve 70 in the longitudinal direction of the developing sleeve 70.
- the straightness of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36 (in other words, the straightness of the coated amount regulating surface 36r) is required to be corrected to 50 ⁇ m or less. Furthermore, in view of the fact that the accuracy of the straightness of a doctor blade made of metal manufactured by secondary cutting work is 20 ⁇ m or less, it is more desirable that the straightness of the coated amount regulating surface 36r of the doctor blade 36 made of resin be corrected to 20 ⁇ m or less.
- the apparatus 100 holds the doctor blade 36 by grasping the grab portions 37 (37P1 to 37p5) of the doctor blade 36 with the fingers 101 (101p1 to 101p5).
- the cameras 102 (102p1 to 102p5) measure the positions of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36 with the grab portions 37 (37P1 to 37p5) of the doctor blade 36 grasped with the fingers 101 (101p1 to 101p5).
- the apparatus 100 detects the outer shape of the coated amount regulating surface 36r of the doctor blade 36.
- the apparatus 100 recognizes the straightness of the coated amount regulating surface 36r based on the central portion of the coated amount regulating surface 36r (the front edge portion 36e3 of the doctor blade 36) with regard to the outer shape of the coated amount regulating surface 36r in the longitudinal direction of the coated amount regulating surface 36r.
- the apparatus 100 moves each of the fingers 101 (101p1 to 101p5) in the direction J in Fig. 9 with the grab portions 37 (37P1 to 37p5) of the doctor blade 36 grasped with the fingers 101.
- the apparatus 100 imparts, to the doctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of the doctor blade 36 via the grab portions 37 of the doctor blade 36 grasped with the fingers 101.
- the grab portions 37 of the doctor blade 36 function as a force receiving portion for receiving a force imparted from the apparatus 100 to the doctor blade 36 to warp at least a part of the area corresponding to the maximum image region of the doctor blade 36.
- the doctor blade 36 (single body) has such a shape that the central portion of the coated amount regulating surface 36r of the doctor blade 36 is greatly warped in/along the longitudinal direction of the doctor blade 36 - that is the widthwise profile of the doctor blade 36 varies along the longitudinal axis/length of the doctor blade 36. Therefore, it is necessary to correct the straightness of the coated amount regulating surface 36r of the doctor blade 36 by reducing differences of positions of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36.
- a method of reducing differences of positions of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36 based on a result of detection of the positions of the front edge portions 36e (36e1 to 36e5) of the doctor blade 36 (the detected outer shape of the coated amount regulating surface 36r) is employed.
- the apparatus 100 corrects the straightness of the coated amount regulating surface 36r to 50 ⁇ m or less by imparting, to the doctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of the doctor blade 36 (hereinafter referred to as a "straightness correction force").
- the apparatus 100 grasps the grab portions 37 (37P1 to 37p5) of the doctor blade 36 placed on the placement board 103 with the fingers 101 (101p1 to 101p5). Then, the apparatus 100 independently moves forward or moves backward each of the fingers 101 along the direction of arrow J in Fig. 9 while grasping the grab portions 37 (37P1 to 37p5) of the doctor blade 36 with the fingers 101 (101p1 to 101p5). At this time, the apparatus 100 imparts, to the doctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of the doctor blade 36 via the grab portions 37 of the doctor blade 36.
- the apparatus 100 sets the outer shapes of the front edge portions 36e1 and 36e5 of the doctor blade 36 as a base, and imparts a straightness correction force to the doctor blade 36 in such a way as to adjust the outer shapes of the front edge portions 36e2, 36e3, and 36e4 to the base.
- the doctor blade 36 externally receives a force for warping at least a part of the area corresponding to the maximum image region of the doctor blade 36 via the grab portions 37 (37P2 to 37p4) provided at three locations among five locations.
- a straightness correction force for correcting the straightness of the coated amount regulating surface 36r is imparted to the front edge portions 36e2 to 36e4 of the doctor blade 36 in the direction of arrow I in Fig. 10 .
- the straightness correction force is imparted to the coated amount regulating surface 36r and, thus, a part of the area corresponding to the maximum image region of the doctor blade 36 is warped, so that the straightness of the coated amount regulating surface 36r of the doctor blade 36 is corrected.
- the shape of the coated amount regulating surface 36r of the doctor blade 36 is corrected from a coated amount regulating surface 36r1 to a coated amount regulating surface 36r2.
- the straightness of the coated amount regulating surface 36r of the doctor blade 36 is able to be corrected to 50 ⁇ m or less.
- the base used for the apparatus 100 to adjust the outer shape of the front edge portions 36e of the doctor blade 36 is set to the outer shapes of the front edge portions 36e1 and 36e5 of the doctor blade 36
- a modification example in which the base is set to the outer shape of the front edge portion 36e3 can be employed.
- the apparatus 100 sets the outer shape of the front edge portion 36e3 of the doctor blade 36 as a base, and imparts a straightness correction force to the doctor blade 36 in such a way as to adjust the outer shapes of the front edge portions 36e1, 36e2, 36e4, and 36e5 to the base.
- the widthwise profile of the doctor blade 36 may be adjusted/warped by application of the correction force so as to straighten the widthwise profile of the doctor blade 36.
- the setting value for straightness correction of the coated amount regulating surface 36r of the doctor blade 36 is set to approximately 20 ⁇ m to 50 ⁇ m, and the magnitude of the straightness correction force to be imparted to the front edge portions 36e of the doctor blade 36 is set to about 500 g.
- setting the magnitude of the straightness correction force to be imparted to the front edge portions 36e of the doctor blade 36 smaller enables the apparatus 100 to be inexpensive and to be miniaturized.
- the magnitude of the straightness correction force to be imparted to the front edge portions 36e of the doctor blade 36 is set based on the magnitude of the rigidity of the doctor blade 36.
- the grab portions 37 are provided at five locations of the doctor blade 36.
- the locations at which the grab portions 37 are provided on the doctor blade 36 may be different to the locations illustrated in Fig. 9 .
- the number of grab portions 37 may be fewer or greater than five. In general, the number of grab portions is determined based on the non-uniformity of the widthwise profile of the doctor blade 36 and/or how many grab portions are required to apply the necessary straight correction forces to correct the widthwise profile.
- each of the grab portions 37 of the doctor blade 36 is in a convex shape, the shape of each of the grab portions 37 is not limited to that.
- the fingers 101 grasp the grab portions 37 of the doctor blade 36. Therefore, as long as the fingers 101 are able to grasp the grab portions 37, the shape of each of the grab portions 37 can be, besides a convex shape, for example, a concave shape, a groove shape, a notch shape, or a flat shape, or can be a combination of some of such shapes. Furthermore, of the drawings for the present specification, except for Fig. 9 to Fig. 12 , the figures in which the doctor blade 36 is illustrated omit the grab portions 37 of the doctor blade 36 from illustration.
- the positioning step is performed in a state in which the developing sleeve 70 is supported by the sleeve supporting portions 42 of the development frame member 30.
- the fingers 101 move the doctor blade 36 from the placement board 103 to the blade attaching portion 41 while holding the doctor blade 36 kept in a warped state in the warping step (in other words, in a state in which the straightness of the coated amount regulating surface 36r has been corrected). Furthermore, the amount of movement and the direction of movement of the fingers 101 (101p1 to 101p5) are previously set according to a program. The fingers 101 (101p1 to 101p5) are driven by actuators and operate according to the previously-set program.
- the apparatus 100 moves the doctor blade 36 kept in a warped state to the blade attaching portion 41 of the development frame member 30.
- the apparatus 100 attaches the doctor blade 36 kept in a warped state to the blade attaching portion 41.
- the doctor blade 36 kept in a warped state enters a state of landing on (also referred to as a "state of abutting on") a blade attaching surface 41s (see Fig. 4 and Fig. 5 ) of the development frame member 30.
- Fig. 11 illustrates a state in which the doctor blade 36 has been caused to land on the blade attaching surface 41s while the grab portions 37 (37P1 to 37p5) of the doctor blade 36 kept in a warped state are grasped by the fingers 101 (101p1 to 101p5).
- the range of a tolerance of the SB gap G (in other words, a range allowed as a tolerance with respect to a target value of the SB gap G) is set to approximately 60 ⁇ m. Since the range of a tolerance of the SB gap G is severe in this way, if the doctor blade 36 is only caused to land on the blade attaching surface 41s of the development frame member 30, the SB gap G is unlikely to fall within an adjustment range of the SB gap G with the range of a tolerance of the SB gap G taken into consideration (in this regard, the adjustment range of the SB gap G including a target value of the SB gap G).
- the apparatus 100 includes cameras 104 (104p1 to 104p5) provided at five locations to respectively measure the positions of the front edge portions 36e (36e1 and 36e5) provided at five locations of the doctor blade 36 caused to land on the blade attaching surface 41s of the development frame member 30 by the fingers 101.
- Each of the cameras 104 (104p1 to 104p5) is arranged along a direction toward the front edge portions 36e (36e1 and 36e5) of the doctor blade 36 (the direction of arrow F in Fig. 11 ), and is able to measure each of the positions of the front edge portions 36e (36e1 and 36e5) of the doctor blade 36.
- the method of measuring (a calculation method for) the magnitude of the SB gap G is described.
- the measurement of the magnitude of the SB gap G is performed in a state in which the developing sleeve 70 is supported by the sleeve supporting portions 42 of the development frame member 30, the doctor blade 36 is attached to the blade attaching portion 41 of the development frame member 30, and the cover frame member 40 is fixed to the development frame member 30.
- a light source for example, a light-emitting diode (LED) or a light guide
- the light source inserted into the development chamber 31 radiates light from the inside of the development chamber 31 toward the SB gap G.
- the cameras 104 capture rays of light exiting from the SB gap G to the outside of the development frame member 30.
- the cameras 104 (104p1 to 104p5) read positions 70a (70a1 to 70a5) at which the developing sleeve 70 is closest to the doctor blade 36 on the surface of the developing sleeve 70, and also read the front edge portions 36e (36e1 and 36e5) of the doctor blade 36.
- the apparatus 100 converts pixel values into distances based on image data read and generated by the cameras 104 (104p1 to 104p5), and calculates the magnitude of the SB gap G based on the distances. In a case where the calculated magnitude of the SB gap G is not within a predetermined range, the apparatus 100 makes adjustment to the SB gap G.
- the apparatus 100 moves the fingers 101 (101p1 to 101p5) along the direction of arrow K in Fig. 12 while grasping the grab portions 37 (37P1 to 37p5) of the doctor blade 36 with the fingers 101.
- the direction of arrow K in Fig. 12 is a direction in which the relative position of the doctor blade 36 with respect to the developing sleeve 70 supported by the sleeve supporting portions 42 of the development frame member 30 is adjusted (in other words, a direction to define the SB gap G).
- the SB gap G calculated at an initial position in which the doctor blade 36 has been caused to land on the blade attaching surface 41s of the development frame member 30 is 350 ⁇ m.
- the adjustment range of the SB gap G is 300 ⁇ m ⁇ 30 ⁇ m and the allowable tolerance of the SB gap G is up to 60 ⁇ m.
- the calculated SB gap G is 50 ⁇ m larger than the nominal value 300 ⁇ m of the SB gap G. Therefore, the fingers 101 translate the doctor blade 36 along the direction of arrow K illustrated in Fig. 12 and in a direction to bring the doctor blade 36 close to the surface of the developing sleeve 70 by 50 ⁇ m while grasping the grab portions 37 of the doctor blade 36.
- the cameras 104 read the positions 70a (70a1 to 70a5) at which the developing sleeve 70 is closest to the doctor blade 36 translated by the fingers 101 and the front edge portions 36e (36e1 and 36e5) of the doctor blade 36 translated by the fingers 101.
- the apparatus 100 recalculates the SB gap G with respect to the doctor blade 36 translated by the fingers 101.
- the apparatus 100 When determining that the magnitude of the calculated SB gap G is within the range of adjustment values of the SB gap G (300 ⁇ m ⁇ 30 ⁇ m), the apparatus 100 ends adjustment of the SB gap G. On the other hand, when determining that the magnitude of the calculated SB gap G is not within the range of adjustment values of the SB gap G (300 ⁇ m ⁇ 30 ⁇ m), the apparatus 100 repeats the above-described adjustment of the SB gap G until the magnitude of the calculated SB gap G falls within the adjustment range of the SB gap G (300 ⁇ m ⁇ 30 ⁇ m).
- the doctor blade 36 is fixed to the blade attaching portion 41 of the development frame member 30, so that the magnitude of the SB gap G can be set to within the adjustment range of the SB gap G.
- a sleeve tube constituting the outer shell of the developing sleeve 70 is made of metal, performing secondary cutting work on the sleeve tube enables the straightness of the surface of the developing sleeve 70 to have a high degree of accuracy such as ⁇ 15 ⁇ m or less.
- the straightness of ⁇ 15 ⁇ m of the surface of the developing sleeve 70 is seen as if the outer diameter of the developing sleeve 70 is apparently varying by ⁇ 15 ⁇ m.
- Figs. 13A and 13B illustrate the positions of the front edge portion 36e of the doctor blade 36 in a state in which the developing sleeve 70 is stopped.
- Fig. 13A illustrates a state in which the SB gap G has been adjusted in a state in which the developing sleeve 70 is stopped at a position far from the doctor blade 36.
- Fig. 13B illustrates a state in which the SB gap G has been adjusted in a state in which the developing sleeve 70 is stopped at a position close to the doctor blade 36.
- Fig. 14 illustrates the position of the front edge portion 36e of the doctor blade 36 in a state in which the developing sleeve 70 is rotating.
- the position of the front edge portion 36e of the doctor blade 36 differs between the states illustrated in Figs. 13A and 13B .
- a difference occurs between the phase of the developing sleeve 70 in the state in which the developing sleeve 70 is stopped at a position far from the doctor blade 36 and the phase of the developing sleeve 70 in the state in which the developing sleeve 70 is stopped at a position close to the doctor blade 36.
- a fluctuation which is moving in and out of the outer diameter line of the developing sleeve 70 (hereinafter referred to as a "fluctuation of the outer diameter of the developing sleeve 70") occurs due to the straightness of the surface of the developing sleeve 70.
- the outer diameter line of the developing sleeve 70 is seen as if the outer diameter line is moving in and out between an outer diameter line 73L1 of the developing sleeve 70 and an outer diameter line 73L2 of the developing sleeve 70 around a center line 73L0 of the fluctuation of the outer diameter of the developing sleeve 70.
- measuring the fluctuation of the outer diameter of the developing sleeve 70 enables detecting the center of the fluctuation of the outer diameter of the developing sleeve 70.
- the method of detecting the center line 73L0 of the fluctuation of the outer diameter of the developing sleeve 70 and measuring the magnitude of the SB gap G based on the center line 73L0 of the fluctuation of the outer diameter of the developing sleeve 70 can be employed.
- the method of using the developing sleeve 70 of the same accuracy and the doctor blade 36 of the same accuracy and using the same adjustment value of the SB gap G while rotating the developing sleeve 70 enables reproducing the position of the front edge portion 36e of the doctor blade 36 at the same position. This enables reducing manufacturing unevenness.
- the apparatus 100 performs the following operation in a state in which the fingers 101 cause the doctor blade 36 to land on the blade attaching surface 41s while translating the doctor blade 36 in a direction to bring the doctor blade 36 close to the surface of the developing sleeve 70.
- the apparatus 100 Before causing the doctor blade 36 to land on the blade attaching surface 41s, the apparatus 100 imparts a straightness correction force for correcting the straightness of the coated amount regulating surface 36r to the doctor blade 36 via the grab portions 37 of the doctor blade 36. More specifically, before causing the doctor blade 36 to land on the blade attaching surface 41s, the apparatus 100 previously corrects the straightness of the coated amount regulating surface 36r to 50 ⁇ m or less. Then, the apparatus 100 causes the doctor blade 36 with the straightness of the coated amount regulating surface 36r corrected to 50 ⁇ m or less to land on the blade attaching surface 41s.
- the apparatus 100 imparts, to the doctor blade 36 via the grab portions 37 of the doctor blade 36, an adjustment force for adjusting the relative position of the coated amount regulating surface 36r of the doctor blade 36 with respect to the developing sleeve 70 so as to cause the SB gap G to fall within a predetermined range (in other words, an adjustment range of the SB gap G) in a state that the doctor blade 36 is fixed to the blade attaching portion 41.
- the fingers 101 warp at least a part of the area corresponding to the maximum image region of the doctor blade 36 in such a manner that the SB gap G measured by the cameras 104 falls within the adjustment range of the SB gap G in a state in which the doctor blade 36 has landed on the blade attaching surface 41s.
- the adjustment of the SB gap G with not only the straightness of the coated amount regulating surface 36r of the doctor blade 36 but also the straightness of the surface of the developing sleeve 70 taken into account can be performed with a higher degree of accuracy.
- the relative position of the coated amount regulating surface 36r of the doctor blade 36 with respect to the developing sleeve 70 can also be performed in such a manner that the tolerance of the SB gap G becomes 60 ⁇ m or less over the longitudinal direction of the developing sleeve 70.
- the doctor blade 36 is fixed to the blade attaching portion 41 according to a fixation step described below.
- the adjustment of the SB gap G only needs to be performed in consideration of the straightness of the coated amount regulating surface 36r, but does not necessarily need to be performed further in consideration of the straightness of the surface of the developing sleeve 70.
- the adjustment of the SB gap G is performed in consideration of the straightness of the coated amount regulating surface 36r of the doctor blade 36, but does not necessarily need to be performed further in consideration of the straightness of the surface of the developing sleeve 70.
- the fixation step is performed in a state in which the doctor blade 36 kept in a warp state in the warping step has landed at a predetermined position of the blade attaching portion 41 of the development frame member 30 determined in the positioning step.
- the apparatus 100 before causing the doctor blade 36 to land on the blade attaching surface 41s of the development frame member 30, the apparatus 100 applies an adhesive A to the blade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region. Then, the apparatus 100 bonds (fixes) the doctor blade 36 kept in a warp state in the warping step to the blade attaching portion 41 over the approximate entirety of the area corresponding to the maximum image region. At this time, the doctor blade 36 is bonded (fixed) to the blade attaching portion 41 in a state in which the straightness of the coated amount regulating surface 36r has been corrected to 50 ⁇ m or less.
- the area warped to correct the straightness of the coated amount regulating surface 36r, of the area corresponding to the maximum image region of the doctor blade 36 is fixed to the blade attaching portion 41. This enables preventing or reducing the area warped to correct the straightness of the coated amount regulating surface 36r, of the area corresponding to the maximum image region of the doctor blade 36, from returning from the state of being warped to the original state obtained before being warped.
- the apparatus 100 may apply the adhesive A to the blade attaching surface 41s.
- the adhesive A is assumed not to be required to be applied to a part of the blade attaching surface 41s.
- the adhesive A being applied to the blade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region means satisfying the following condition.
- the condition is that the adhesive A is applied to an area which includes an area warped to correct the straightness of the coated amount regulating surface 36r of the area corresponding to the maximum image region of the doctor blade 36 and which is 95% or more of the area corresponding to the maximum image region in the longitudinal direction of the blade attaching surface 41s.
- the adhesive A is required to have such an adhesive strength that the doctor blade 36 is prevented from coming unglued from the blade attaching surface 41s of the development frame member 30 in the process of an image forming operation (development operation).
- the load which is imparted to the doctor blade 36 in the process of an image forming operation (development operation) is about 2 kilogram-force (kgf) at the time of drop test, and, if the doctor blade 36 receiving such a magnitude of load does not come unglued from the blade attaching surface 41s of the development frame member 30, there is no problem. Therefore, it has been known that a sufficient adhesive strength can be ensured even with a general adhesive A, and, from a viewpoint of ensuring mass productivity, the shorter the hardening time of the adhesive A the better.
- the film thickness of the adhesive A which is applied to the blade attaching surface 41s of the development frame member 30 is described.
- the adhesive A is arranged to intervene between the doctor blade 36 and the blade attaching surface 41s of the development frame member 30.
- the relationship between the film thickness of thee adhesive A and the magnitude of a breaking load of a portion bonded with the adhesive A is such a relationship that the larger the amount of the adhesive A, the larger the adhesive strength caused by the adhesive A becomes.
- the load which is imparted to the doctor blade 36 in the process of an image forming operation (development operation) is about 2 kgf
- the strength required as the adhesive strength of the adhesive A is set to 10 kgf or more. Therefore, to ensure 10 kgf or more as the adhesive strength of the adhesive A, the film thickness of the adhesive A which is applied to the blade attaching surface 41s of the development frame member 30 only needs to be set to 20 ⁇ m or more.
- the relationship between the thickness with which to apply the adhesive A and the magnitude of dimensional variability in the thickness direction of the adhesive A is described.
- the larger the film thickness of the adhesive A the more the dimensional variability in the thickness direction of the adhesive A caused by contraction of the adhesive A at the time of hardening of the adhesive A occurs.
- the magnitude of dimensional variability in the thickness direction of the adhesive A when the film thickness of the adhesive A is 150 ⁇ m is only about 8 ⁇ m larger than the magnitude of dimensional variability in the thickness direction of the adhesive A when the film thickness of the adhesive A is 30 ⁇ m.
- the upper limit of the film thickness of the adhesive A which is applied to the blade attaching surface 41s of the development frame member 30 is not determined based on the influence of contraction of the adhesive A but can be determined based on individual production requirements, such as the hardening time or cost of the adhesive A.
- the adhesive A is applied to the blade attaching portion 41 side
- a modification example in which the adhesive A is applied to the doctor blade 36 side or a modification example in which the adhesive A is applied to both the blade attaching portion 41 side and the doctor blade 36 side can be employed.
- the timing at which to apply the adhesive A to the blade attaching portion 41 side is prior to starting of the positioning step (more desirably, parallel with the warping step)
- the total time required for a series of steps of the fixation method for the doctor blade 36 can be shortened.
- this example means a series of steps of applying the adhesive A to the blade attaching portion 41 of the development frame member 30 while correcting the straightness of the coated amount regulating surface 36r. Therefore, in the first exemplary embodiment, the following description proceeds on the assumption that the step of applying the adhesive A to the blade attaching portion 41 side of the development frame member 30 is performed prior to starting of the positioning step.
- the adjustment of the SB gap G is required to be completed before the adhesive A hardens.
- the time in which the adhesive A hardens is determined based on the material of the adhesive A or the amount of application of the adhesive A. Therefore, the time in which the adhesive A hardens can be predicted to some extent.
- the number of times the adjustment of the SB gap G can be repeatedly performed before the adhesive A hardens is previously determined based on the time required for the adjustment of the SB gap G to be performed once. Therefore, as long as the range of the determined number of times is not exceeded, since the adhesive A has not yet hardened, the adjustment of the SB gap G can be repeatedly performed.
- the apparatus 100 stores, in a memory included in the apparatus 100, information about a position at which to fix the doctor blade 36 to the blade attaching surface 41s of the development frame member 30, which has been determined during the adjustment of the SB gap G. Then, after the positioning step is completed, the apparatus 100 performs a step of applying the adhesive A to the blade attaching portion 41 side of the development frame member 30.
- the apparatus 100 causes the doctor blade 36 kept in a warped state in the warping step to land on the blade attaching surface 41s of the development frame member 30 based on the information about the fixation position for the doctor blade 36 stored in the memory. Then, after the doctor blade 36 kept in a warped state lands on the blade attaching surface 41s, the apparatus 100 can start the above-described fixation step.
- the degree of close contact between the doctor blade 36 and the blade attaching portion 41 is important. This is because, in a case where a gap between the doctor blade 36 and the blade attaching portion 41 is large, even if the adhesive A intervenes in the gap, the adhesive strength becomes weak.
- the apparatus 100 drops a weight having a predetermined weight on the doctor blade 36, thus imparting a load for bringing the doctor blade 36 into close contact with the blade attaching portion 41.
- the fingers 101 have to continue holding the doctor blade 36 until the adhesive A sufficiently hardens. For example, in a case where the hardening time of the adhesive A is 15 seconds, the load for bringing the doctor blade 36 into close contact with the blade attaching portion 41 can be configured to continue being imparted for 20 seconds in view of tolerances.
- the apparatus 100 raises the weight, thus removing the load from the doctor blade 36. Then, the apparatus 100 causes the fingers 101 (101p1 to 101p5) to operate, and, after moving the fingers 101 (101p1 to 101p5) away from the doctor blade 36, moves the fingers 101 (101p1 to 101p5) to a preparatory position for a next operation.
- the apparatus 100 previously corrects the straightness of the coated amount regulating surface 36r to 50 ⁇ m or less has been described.
- the SB gap G can be configured to fall within the adjustment range of the SB gap G in a state that the doctor blade 36 is fixed to the blade attaching portion 41.
- the function of performing the warping step and the function of performing the positioning step are performed by respective separate apparatuses 100. More specifically, the doctor blade 36 (single body) is placed on the placement board 103 of the apparatus 100 for performing the warping step, which is an apparatus different from the apparatus 100 for performing the positioning step. Then, with the doctor blade 36 (single body) placed on the placement board 103, the apparatus 100 for performing the warping step imparts, to the doctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of the doctor blade 36.
- the single apparatus 100 does not previously correct the straightness of the coated amount regulating surface 36r to 50 ⁇ m or less before causing the doctor blade 36 the accuracy of the coated amount regulating surface 36r of which is about 300 ⁇ m to 500 ⁇ m to land on the blade attaching surface 41s. Instead, after causing the doctor blade 36 to land on the blade attaching surface 41s, until the adhesive A hardens, the single apparatus 100 warps at least a part of the area corresponding to the maximum image region of the doctor blade 36 in such a manner that the SB gap G falls within the adjustment range of the SB gap G.
- this modification example means a series of steps of, while fixing the doctor blade 36 to the blade attaching surface 41s, warping at least a part of the area corresponding to the maximum image region of the doctor blade 36 in such a manner that the SB gap G falls within a predetermined range (in other words, the adjustment range of the SB gap G).
- a predetermined range in other words, the adjustment range of the SB gap G.
- the straightness of the coated amount regulating surface is about 300 ⁇ m to 500 ⁇ m. From this, it is desirable that the apparatus 100 previously correct the straightness of the coated amount regulating surface 36r to 50 ⁇ m or less before causing the doctor blade 36 to land on the blade attaching surface 41s. This is because, since the adjustment of the SB gap G is performed with the straightness of the coated amount regulating surface 36r corrected to 50 ⁇ m or less, the required adjustment time becomes shorter as compared with the case of performing the adjustment of the SB gap G with the straightness of the coated amount regulating surface 36r being about 300 ⁇ m to 500 ⁇ m.
- the time required for a step performed with the doctor blade 36 landing on the blade attaching surface 41s becomes shorter, the time required for the adhesive A applied to the blade attaching surface 41s to harden can be set shorter.
- the case where the function for performing the warping step and the function for performing the positioning step are included in the respective separate apparatuses 100 enables generally shortening the takt time as compared with the case where both functions are included in the single apparatus 100, and is, therefore, advantageous in terms of mass productivity.
- Fig. 15 is a sectional view of the development device 3 in a cross-section perpendicular to the rotational axis of the developing sleeve 70 (the cross-section H in Fig. 2 ). Moreover, Fig. 15 illustrates a configuration near the doctor blade 36 fixed to the blade attaching portion 41 of the development frame member 30 with the adhesive A.
- a line connecting a position of the doctor blade 36 closest to the developing sleeve 70 in the coated amount regulating surface 36r to the rotational center of the developing sleeve 70 is set as the X-axis.
- the length in the X-axis direction of the doctor blade 36 is large, and the rigidity thereof in a cross-section in the X-axis direction is also large.
- the ratio of the cross-sectional area T1 of the doctor blade 36 to the cross-sectional area T2 of the wall portion 30a of the development frame member 30 located near the developer guide portion 35 is small.
- the rigidity of the development frame member 30 (single body) is set 10 times or larger than the rigidity of the doctor blade 36 (single body). Accordingly, in a state in which the doctor blade 36 is fixed to the blade attaching portion 41 of the development frame member 30, the rigidity of the development frame member 30 becomes more dominant than the rigidity of the doctor blade 36. As a result, in the process of an image forming operation (development operation), the amount of displacement (the maximum amount of warp) of the coated amount regulating surface 36r of the doctor blade 36 obtained when the doctor blade 36 has received the developer pressure becomes substantially equivalent to the amount of displacement (the maximum amount of warp) of the development frame member 30.
- a developer scooped up by the first conveyance screw 33 passes through the developer guide portion 35 and is then conveyed to the surface of the developing sleeve 70.
- the doctor blade 36 is receiving the developer pressure from various directions. As illustrated in Fig. 15 , when a direction perpendicular to the X-axis direction (a direction to define the SB gap G) is set as the Y-axis, the developer pressure in the Y-axis direction is perpendicular to the blade attaching surface 41s of the development frame member 30.
- the developer pressure in the Y-axis direction becomes a force in a direction to unglue the doctor blade 36 from the blade attaching surface 41s. Therefore, the bonding force caused by the adhesive A is required to be sufficiently large with respect to the developer pressure in the Y-axis direction.
- the adhesion area or application thickness of the adhesive A with respect to the blade attaching surface 41s is optimized in consideration of the force acting in a direction to unglue the doctor blade 36 from the blade attaching surface 41s or the adhesion force of the adhesive A.
- the doctor blade 36 can be prevented or reduced from being deformed by the developer pressure in the process of an image forming operation (development operation).
- the heat generated in the process of a development operation includes, for example, heat generated during rotation of the rotation shaft of the developing sleeve 70 with respect to the bearings 71, heat generated during rotation of the rotation shaft 33a of the first conveyance screw 33 with respect to the bearing members, and heat generated by the developer passing through the SB gap G.
- the temperature around the development device 3 changes due to these types of heat generated in the process of an image forming operation (development operation), so that the temperatures of the doctor blade 36, the development frame member 30, and the cover frame member 40 also change.
- the first exemplary embodiment employs a method of fixing the doctor blade 36 to the blade attaching portion 41 of the development frame member 30 with the adhesive A over the approximate entirety of the area corresponding to the maximum image region.
- the following problem arises when a temperature change has occurred. Specifically, when a temperature change has occurred, the amount of deformation (amount of expansion and contraction) of the doctor blade 36 caused by the temperature change and the amount of deformation (amount of expansion and contraction) of the development frame member 30 caused by the temperature change may become different from each other.
- the doctor blade 36 is fixed to the blade attaching surface 41s at least at a first area, a second area, and a third area in the area corresponding to the maximum image region of the doctor blade 36 (for example, at least at three locations including both end portions and a central portion of the area corresponding to the maximum image region of the doctor blade 36).
- the warp of the doctor blade 36 may become large, so that the doctor blade 36 may be greatly warped.
- the magnitude of the SB gap G may be varied due to a temperature change in the process of an image forming operation (development operation).
- the doctor blade 36 is fixed to the blade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region of the doctor blade 36, it is necessary to prevent or reduce a variation of the magnitude of the SB gap G caused by a temperature change in the process of an image forming operation (development operation).
- the amount of extension of the doctor blade 36 caused by a temperature change is H [ ⁇ m] and the amount of extension of the blade attaching surface 41s of the blade attaching portion 41 of the development frame member 30 caused by a temperature change is I [ ⁇ m].
- the linear expansion coefficient ⁇ 1 of a resin that makes up the doctor blade 36 and the linear expansion coefficient ⁇ 2 of a resin that makes up the development frame member 30 differ from each other.
- a difference of these linear expansion coefficients causes a difference in the amount of deformation caused by a temperature change between the development frame member 30 and the doctor blade 36, so that, to make up for the difference between the amounts of extension H [ ⁇ m] and I [ ⁇ m], the doctor blade 36 would deform along the direction of arrow J in Fig. 16 .
- the deformation of the doctor blade 36 along the direction of arrow J in Fig. 16 is hereinafter referred to as a "deformation in a warp direction of the doctor blade 36". Then, the deformation in a warp direction of the doctor blade 36 would lead to a variation of the magnitude of the SB gap G.
- Each of the linear expansion coefficient ⁇ 2 of a resin that makes up the sleeve supporting portions 42 and the blade attaching portion 41 of the development frame member 30 (single body) and the linear expansion coefficient ⁇ 1 of a resin that makes up the doctor blade 36 (single body) is related to preventing or reducing a variation of the magnitude of the SB gap G caused by heat.
- the difference of the linear expansion coefficient ⁇ 2 of a resin that makes up the development frame member 30, which includes the sleeve supporting portions 42 and the blade attaching portion 41, from the linear expansion coefficient ⁇ 1 of a resin that makes up the doctor blade 36 is hereinafter referred to as a "linear expansion coefficient difference ⁇ 2- ⁇ 1".
- a change of the maximum amount of warp of the doctor blade 36 caused by the linear expansion coefficient difference ⁇ 2- ⁇ 1 is described with use of Table 1.
- the resin that makes up the development frame member 30 and the resin that makes up the doctor blade 36 can be selected in such a manner that the linear expansion coefficient difference ⁇ 2- ⁇ 1 becomes -0.45 ⁇ 10 -5 [m/°C] or more and 0.55 ⁇ 10 -5 [m/°C] or less. Selecting resins in such a manner that the linear expansion coefficient difference ⁇ 2- ⁇ 1 satisfies the relational expression (1) as the resin that makes up the development frame member 30 and the resin that makes up the doctor blade 36 enables limiting the amount of variation of the SB gap G caused by heat to ⁇ 20 ⁇ m or less. It is more desirable that the linear expansion coefficient difference ⁇ 2- ⁇ 1 be set to zero. To set the linear expansion coefficient difference ⁇ 2- ⁇ 1 to zero, the same resin can be selected as the resin that makes up the development frame member 30 and the resin that makes up the doctor blade 36.
- the cover frame member 40 is fixed to the development frame member 30, if the amounts of deformation of the development frame member 30 and the cover frame member 40 caused by heat differ from each other, the deformation of the cover frame member 40 along the warp direction would lead to a variation of the magnitude of the SB gap G. As a result, even if the SB gap G is adjusted with a high degree of accuracy in the positioning step for the doctor blade 36, the magnitude of the SB gap G may be varied due to a temperature change in the process of an image forming operation (development operation).
- Each of the linear expansion coefficient ⁇ 2 of a resin that makes up the sleeve supporting portions 42 and the blade attaching portion 41 of the development frame member 30 (single body) and the linear expansion coefficient ⁇ 3 of a resin that makes up the cover frame member 40 (single body) is related to preventing or reducing a variation of the magnitude of the SB gap G caused by a temperature change. As mentioned above, it is necessary to limit the amount of variation of the SB gap G caused by heat to ⁇ 20 ⁇ m or less.
- the linear expansion coefficient of a resin that makes up the development frame member 30, which includes the sleeve supporting portions 42 and the blade attaching portion 41 is ⁇ 2 [m/°C] and the linear expansion coefficient of a resin that makes up the cover frame member 40 is ⁇ 3 [m/°C].
- the difference of the linear expansion coefficient ⁇ 3 of a resin that makes up the cover frame member 40 from the linear expansion coefficient ⁇ 2 of a resin that makes up the development frame member 30, which includes the sleeve supporting portions 42 and the blade attaching portion 41, is hereinafter referred to as a "linear expansion coefficient difference ⁇ 3- ⁇ 2".
- a linear expansion coefficient difference ⁇ 3- ⁇ 2 As with Table 1, it is necessary to satisfy the following relational expression (2) with regard to the linear expansion coefficient difference ⁇ 3- ⁇ 2. ⁇ 0.45 ⁇ 10 ⁇ 5 m / ° C ⁇ ⁇ 3 ⁇ ⁇ 2 ⁇ 0.55 ⁇ 10 ⁇ 5 m / ° C
- the resin that makes up the development frame member 30 and the resin that makes up the cover frame member 40 can be selected in such a manner that the linear expansion coefficient difference ⁇ 3- ⁇ 2 becomes -0.45 ⁇ 10 -5 [m/°C] or more and 0.55 ⁇ 10 -5 [m/°C] or less. Selecting resins in such a manner that the linear expansion coefficient difference ⁇ 3- ⁇ 2 satisfies the relational expression (2) as the resin that makes up the development frame member 30 and the resin that makes up the cover frame member 40 enables limiting the amount of variation of the SB gap G caused by heat to ⁇ 20 ⁇ m or less. It is more desirable that the linear expansion coefficient difference ⁇ 3- ⁇ 2 be set to zero. To set the linear expansion coefficient difference ⁇ 3- ⁇ 2 to zero, the same resin can be selected as the resin that makes up the development frame member 30 and the resin that makes up the cover frame member 40.
- the linear expansion coefficient of the doctor blade 36 or the development frame member 30 with the adhesive A applied thereto would vary.
- the volume itself of the adhesive A applied to the doctor blade 36 or the development frame member 30 is very small, so that an influence on a change in dimension in the thickness direction of the adhesive A caused by a temperature change is at an ignorable level. Therefore, the deformation of the doctor blade 36 in a warp direction caused by the linear expansion coefficient difference ⁇ 2- ⁇ 1 varying when the adhesive A is applied to the doctor blade 36 or the development frame member 30 is at an ignorable level.
- abrasion resistance of the doctor blade 36 includes a developer pressure to be imparted to the doctor blade 36.
- a resin that makes up the doctor blade 36 it has been known that a resin with a larger surface hardness is more excellent in abrasion resistance.
- a resin having a surface hardness of 100 or more in the scale L of Rockwell hardness JIS K7202-2
- JIS K7202-2 a resin having a surface hardness of 100 or more in the scale L of Rockwell hardness
- the doctor blade 36 made of such a resin has only an abrasion of 10 ⁇ m or less even in an endurance test using the equivalence of about 500,000 sheets of paper. While the larger the surface hardness of the doctor blade 36, the more the abrasion resistance of the doctor blade 36 is improved, the mass productivity of the doctor blade 36 tends to decrease.
- a resin with a large surface hardness generally contains much toughening agent such as glass fiber.
- the toughening agent contained in the resin may damage the mold. Therefore, in a case where more than a given amount of toughening agent is contained in a resin, the mass productivity of the doctor blade 36 becomes unable to be maintained. Therefore, it has been known that selecting a resin having a surface hardness of 100 or less in the scale M of Rockwell hardness (JIS K7202-2) as the resin that makes up the doctor blade 36 enables ensuring the mass productivity of the doctor blade 36.
- the doctor blade 36 is molded with use of a resin having a surface hardness of 100 or more in the scale L of Rockwell hardness and 100 or less in the scale M of Rockwell hardness.
- the resin having a surface hardness of 100 or more in the scale L of Rockwell hardness and 100 or less in the scale M of Rockwell hardness includes the following examples.
- the resin includes a resin having a base material of polyphenylene ether (PPE) and polystyrene (PS) and containing a toughening agent in the range of 30% by weight or more and 35% by weight or less (hereinafter referred to as a "resin X").
- the resin includes a resin having a base material of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) and containing a toughening agent in the range of 20% by weight or more and 30% by weight or less (hereinafter referred to as a "resin Y").
- PC polycarbonate
- ABS acrylonitrile butadiene styrene
- Y a toughening agent in the range of 20% by weight or more and 30% by weight or less
- the "resin X" or the “resin Y” is selected as the resin that makes up the doctor blade 36.
- a resin that makes up the development frame member 30 can be selected in such a manner that the difference of the linear expansion coefficient ⁇ 2 of the development frame member 30 from the linear expansion coefficient ⁇ 1 of the doctor blade 36 (the linear expansion coefficient difference ⁇ 2- ⁇ 1) satisfies the above-mentioned relational expression (1).
- the resin X" or the "resin Y" can be selected as the resin that makes up the cover frame member 40.
- the difference of the linear expansion coefficient ⁇ 2 of the development frame member 30 from the linear expansion coefficient ⁇ 3 of the cover frame member 40 (the linear expansion coefficient difference ⁇ 2- ⁇ 3) satisfies the above-mentioned relational expression (2).
- the linear expansion coefficient difference ⁇ 2- ⁇ 3 satisfies the above-mentioned relational expression (2) .
- a doctor blade 36 in which the accuracy of the straightness of the coated amount regulating surface 36r is the accuracy of a general resin product is used. Then, in a state in which the straightness of the coated amount regulating surface 36r has been corrected by warping a part of the area corresponding to the maximum image region of the doctor blade 36, the doctor blade 36 is configured to be fixed to the blade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region.
- the SB gap G can be configured to fall within the range of about 300 ⁇ m ⁇ 30 ⁇ m (in other words, the adjustment range of the SB gap G).
- the resin that makes up the doctor blade 36 is selected in view of both the abrasion resistance and mass productivity of the doctor blade 36. Then, the resin that makes up the development frame member 30 is selected in such a manner that the difference of the linear expansion coefficient ⁇ 2 of the development frame member 30 from the linear expansion coefficient ⁇ 1 of the doctor blade 36 (the linear expansion coefficient difference ⁇ 2- ⁇ 1) satisfies the above-mentioned relational expression (1).
- the resin that makes up the cover frame member 40 is selected in such a manner that the difference of the linear expansion coefficient ⁇ 2 of the development frame member 30 from the linear expansion coefficient ⁇ 3 of the cover frame member 40 (the linear expansion coefficient difference ⁇ 2- ⁇ 3) satisfies the above-mentioned relational expression (2).
- the linear expansion coefficient difference ⁇ 2- ⁇ 3 satisfies the above-mentioned relational expression (2).
- the doctor blade 36 is configured to be fixed to the blade attaching portion 41 of the development frame member 30 over the approximate entirety of the area corresponding to the maximum image region.
- the rigidity of the doctor blade 36 in a state of being fixed to the development frame member 30 can be made larger as compared with the case of fixing only both end portions (two locations) of the doctor blade 36 in the longitudinal direction of the doctor blade 36 to the blade attaching portion 41.
- a variation of the magnitude of the SB gap G caused by the developer pressure being imparted to the doctor blade 36 in the process of an image forming operation (development operation) can be prevented or reduced.
- the adhesive A is applied to the blade attaching surface 41s of the development frame member 30 over the approximate entirety of the area corresponding to the maximum image region.
- the adhesive A being applied to the blade attaching surface 41s of the development frame member 30 over the approximate entirety of the area corresponding to the maximum image region causes an area warped of the area corresponding to the maximum image region of the doctor blade 36 to be fixed to the blade attaching surface 41s.
- an area warped to correct the straightness of the coated amount regulating surface 36r of the area corresponding to the maximum image region of the doctor blade 36 is prevented or reduced from returning from the warped state to an original state obtained before being warped.
- a second exemplary embodiment of the invention differs from the first exemplary embodiment in that the apparatus 100 applies the adhesive A to the blade attaching surface 41s of the development frame member 30 not over the approximate entirety of the area corresponding to the maximum image region.
- the apparatus 100 stores, in the memory, information about an area warped to correct the straightness of the coated amount regulating surface 36r of the area corresponding to the maximum image region of the doctor blade 36.
- the apparatus 100 determines a given area to which to apply the adhesive A of the area corresponding to the maximum image region of the blade attaching surface 41s of the development frame member 30 based on the information about an area warped of the doctor blade 36 stored in the memory.
- the apparatus 100 applies the adhesive A to the determined given area of the blade attaching surface 41s. Furthermore, the application width or film thickness of the adhesive A to be applied to the blade attaching surface 41s can be determined based on the adhesion strength of the adhesive A or the amount of application of the adhesive A in view of man-hour or cost. With this, the area warped of the area corresponding to the maximum image region of the doctor blade 36 is fixed to the blade attaching surface 41s.
- the apparatus 100 further apply the adhesive A to at least three locations including both end portions and an approximate central portion of the area corresponding to the maximum image region of the blade attaching surface 41s of the development frame member 30 in addition to the determined given area of the blade attaching surface 41s.
- the approximate central portion of the area corresponding to the maximum image region of the blade attaching surface 41s is assumed to cover an area obtained by translating the central portion of the area corresponding to the maximum image region of the blade attaching surface 41s toward one end side or toward the other end side by a length that is 10% or less of the length in the longitudinal direction of the area.
- Fig. 17 is a perspective view illustrating a configuration of a development device 300 in which three locations including both end portions and an approximate central portion of the area corresponding to the maximum image region of the doctor blade 36 are fixed to the blade attaching surface 41s with screws 80.
- Fig. 18 is a sectional view of the development device 300 in a cross-section H in Fig.
- FIG. 17 illustrates a configuration near the doctor blade 36 fixed to the blade attaching portion 41 of the development frame member 30 with the screws 80.
- members assigned with the respective same reference characters as those in Fig. 2 have the respective same configurations.
- members assigned with the respective same reference characters as those in Fig. 15 have the respective same configurations.
- insert nuts are inserted at fixation positions of the blade attaching surface 41s of the development frame member 30. Then, the screws 80 are fastened to the insert nuts, so that the fastening power for fixing the doctor blade 36 to the blade attaching surface 41s is increased. As long as the fastening power can be maintained, instead of the insert nuts, self-tapping screws can be used for fastening in such a manner that the screws 80 can tap their own holes as the screws 80 are driven.
- the doctor blade 36 can be fixed to the blade attaching surface 41s with the screws 80. Furthermore, the grab portions 37 of the doctor blade 36 are located at positions each obtained by shifting a length equivalent to a fixed width per location by the screw 80 with respect to a screw fastening portion provided on the doctor blade 36 for fastening by the screw 80 to the blade attaching surface 41s.
- the fixed width per location by the screw 80 is equivalent to the width occupied by the screw 80 for fastening, and is about 5 mm.
- the invention is not limited to the above-described exemplary embodiments, but can be modified or altered in various manners (including an organic combination of some or all of the exemplary embodiments) based on the gist of the invention, which are not excluded from the scope of the claims.
- the developer guide portion 35 and the development frame member 30 are configured as an integrally formed member and the developer guide portion 35 and the doctor blade 36 are configured as separately formed members
- the exemplary embodiments are not limited to this example.
- the rigidity of the doctor blade 36 (single body) allows the fingers 101 to warp the doctor blade 36 and the flow of a developer or the developer pressure in the process of a development operation is within the range of design values, the developer guide portion 35 and the doctor blade 36 can be configured as an integrally formed member.
- each photosensitive drum 1 constitutes a rotatable image bearing member which bears a toner image.
- the development device 3 having a configuration in which the developing sleeve 70 rotates counterclockwise and the doctor blade 36 is located below the developing sleeve 70 has been described as an example, the exemplary embodiments are not limited to this example.
- the invention can also be applied to a development device 3 having a configuration in which the developing sleeve 70 rotates clockwise and the doctor blade 36 is located above the developing sleeve 70.
- the development device 3 having a configuration in which the development chamber 31 and the agitation chamber 32 are arranged horizontally side by side with respect to the horizontal direction has been described as an example, the exemplary embodiments are not limited to this example.
- the invention can also be applied to a development device 3 having a configuration in which the development chamber 31 and the agitation chamber 32 are arranged vertically side by side with respect to the direction of gravitational force.
- the development device 3 has been described as a single unit, even a configuration formed as a process cartridge, which is obtained by unitizing the image forming unit 600 (see Fig. 1 ) including the development device 3 and is configured to be detachably attached to the image forming apparatus 60, can attain a similar advantageous effect.
- the invention can be applied to any image forming apparatus 60 including such a development device 3 or process cartridge regardless of monochrome image forming apparatuses and color image forming apparatuses.
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Description
- The present invention generally relates to a method of fixing a regulating blade made of, for example, resin. It also related to a development device equipped with the regulating blade made of resin, for example.
- A development device is equipped with a regulating blade (a developer regulating member) which has a coated amount regulating surface (a regulating portion) used to regulate the amount (a developer coated amount) of a developer borne (e.g. carried) on the surface of a developer bearing member, which bears (e.g. carries) a developer used to develop an electrostatic latent image formed on an image bearing member. The regulating blade is arranged to face the developer bearing member over the longitudinal direction of the developer bearing member via a predetermined gap between the regulating blade and the surface of the developer bearing member (the gap being hereinafter referred to as an "SB gap G"). The SB gap G is the shortest distance between the surface of the developer bearing member, which is supported by a frame member of a developer container (a development frame member), and the coated amount regulating surface of the regulating blade, which is attached to the frame member of the developer container. Adjusting the size of the SB gap G enables adjusting the amount of a developer to be conveyed to a development region at which the developer bearing member faces the image bearing member.
- A development device discussed in Japanese Patent Application Laid-Open No.
2014-197175 - In association with an increase in the width of a sheet on which to form an image, the area of a coated amount regulating surface corresponding to an image region able to be formed on an image bearing member becomes larger, so that the length in the longitudinal direction of a regulating blade becomes larger. In a case where a regulating blade the length of which in the longitudinal direction thereof is large is molded with resin, it is difficult to ensure the straightness of the coated amount regulating surface of the regulating blade made of resin, which is molded with resin. This is because, when a regulating blade the length of which in the longitudinal direction thereof is large is molded with resin, variations are likely to occur in ratios in which thermally-expanded resin thermally contracts. Therefore, in the case of a regulating blade made of resin, as the length in the longitudinal direction of the regulating blade becomes larger, due to the straightness of the coated amount regulating surface of the regulating blade, the SB gap G tends to become more likely to vary in the longitudinal direction of the developer bearing member. If the SB gap G varies in the longitudinal direction of the developer bearing member, variations in the longitudinal direction of the developer bearing member may occur in the amount of a developer to be borne on the surface of the developer bearing member.
- Therefore, in a development device equipped with a regulating blade made of resin, it is desirable that the SB gap G be within a predetermined range over the longitudinal direction of the developer bearing member in a state that the regulating blade is fixed to a blade attaching portion of the development frame member, irrespective of the straightness of the coated amount regulating surface of the regulating blade.
- Aspects of the present invention are preferably directed to providing a method of fixing a regulating blade to a development device, particularly in cases where the regulating blade is made of resin and has a regulating portion which is not straight. In some arrangements, a gap between a developer bearing member and the regulating portion is formed. The gap may be within a predetermined range over the longitudinal direction of the developer bearing member. The gap may be formed after the regulating blade is fixed to a blade attaching portion of a development frame member.
- According to a first aspect the invention provides a method of fixing a development frame member as specified in any one of
claims 1 to 6. For example, in some embodiments, the invention provides a method of attaching a regulating blade made of resin to an attaching portion of a development frame member made of resin, the attaching portion being used to attach the regulating blade, the regulating blade being (i) arranged in non-contact with a developer bearing member that is arranged to carry a developer for developing an electrostatic latent image formed on an image bearing member, (ii) arranged to face the developer bearing member, and (iii) configured to regulate an amount of the developer to be carried on the developer bearing member, characterized in that the method of attaching the regulating blade comprising: - a warping step comprising imparting, to the regulating blade, a force for warping the regulating blade in such a manner that a gap between the developer bearing member supported by the development frame member and the regulating blade attached to the attaching portion is adjusted to within a predetermined range along a longitudinal direction of the developer bearing member; and
- an attaching step comprising attaching with an adhesive, the regulating blade to the attaching portion in a state in which the regulating blade is kept warped by the force imparted to the regulating blade in the warping step and the gap is within the predetermined range along the longitudinal direction of the developer bearing member.
- According to a second aspect of the present invention, there is provided a development device as specified in claims 7 to 10. In some embodiments, for example, there is provided a development device comprising:
- a developer bearing member configured to carry a developer for developing an electrostatic latent image formed on an image bearing member;
- a regulating blade made of resin, the regulating blade being (i) arranged in non-contact with the developer bearing member, (ii) arranged to face the developer bearing member and (iii) configured to regulate an amount of the developer to be carried on the developer bearing member; and
- a development frame member made of resin including an attaching portion for attaching the regulating blade,
- characterized in that:
- the regulating blade includes a force receiving portion for receiving a force for warping the regulating blade in such a manner that a gap between the developer bearing member supported by the development frame member and the regulating blade attached to the attaching portion is adjusted to within a predetermined range along a longitudinal direction of the developer bearing member; and
- the regulating blade is fixed to the attaching portion in a state in which the regulating blade is warped.
- The developer bearing member may be a rotatable developing sleeve as described herein (
e.g. item 70 inFig. 2 ). The image bearing member may be a photosensitive drum as described herein (e.g. item 1 inFig. 1 ). The regulating blade is deformable and may be a doctor blade as described herein (e.g. item 36 inFig. 2 ). The development device is preferably part of an image forming apparatus. The regulating blade is ideally separated from the developer bearing member by the gap. - Further features, advantages and aspects of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. It should be understood that any of the features described herein in relation to a particular embodiment or set of embodiments may be combined with the features of one or more other embodiments without any limitations other than those imparted by the broadest aspects of the invention as defined hereinabove. In particular, features from different embodiments can be combined where necessary or where the combination of elements or features from individual embodiments in a single embodiment is beneficial.
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Fig. 1 is a sectional view illustrating a configuration of an image forming apparatus. -
Fig. 2 is a perspective view illustrating a configuration of a development device according to a first exemplary embodiment. -
Fig. 3 is a perspective view illustrating the configuration of the development device according to the first exemplary embodiment. -
Fig. 4 is a sectional view illustrating the configuration of the development device according to the first exemplary embodiment. -
Fig. 5 is a perspective view illustrating a configuration of a development frame member (single body) made of resin. -
Fig. 6 is a perspective view illustrating a configuration of a doctor blade (single body) made of resin. -
Fig. 7 is a schematic diagram used to explain the rigidity of the doctor blade (single body) made of resin. -
Fig. 8 is a schematic diagram used to explain the rigidity of the development frame member (single body) made of resin. -
Fig. 9 is a schematic diagram used to explain steps of a method of fixing the doctor blade made of resin. -
Fig. 10 is a schematic diagram used to explain steps of the method of fixing the doctor blade made of resin. -
Fig. 11 is a schematic diagram used to explain steps of the method of fixing the doctor blade made of resin. -
Fig. 12 is a schematic diagram used to explain steps of the method of fixing the doctor blade made of resin. -
Figs. 13A and 13B are schematic diagrams used to explain steps of the method of fixing the doctor blade made of resin. -
Fig. 14 is a schematic diagram used to explain steps of the method of fixing the doctor blade made of resin. -
Fig. 15 is a sectional view used to explain a deformation of the doctor blade made of resin caused by a developer pressure. -
Fig. 16 is a perspective view used to explain a deformation of the doctor blade made of resin caused by a temperature change. -
Fig. 17 is a perspective view illustrating a configuration of a development device according to a second exemplary embodiment. -
Fig. 18 is a sectional view illustrating the configuration of the development device according to the second exemplary embodiment. - Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings. Furthermore, the following exemplary embodiments should not be construed to limit the invention set forth in claims, and not all of the combinations of features described in a first exemplary embodiment of the invention are necessarily essential for solutions in the invention. The invention can be implemented for various use applications, such as printers, various types of printing machines, copying machines, facsimile apparatuses, and multifunction peripherals.
- First, a configuration of an image forming apparatus according to the first exemplary embodiment of the invention is described with reference to the sectional view of
Fig. 1 . As illustrated inFig. 1 , theimage forming apparatus 60 includes fourimage forming units 600 arranged from the upstream side to the downstream side along an endless intermediate transfer belt (ITB) 61, serving as an intermediate transfer member, and along the rotational direction of the intermediate transfer belt 61 (the direction of arrow C inFig. 1 ). Theimage forming units 600 form images of the respective colors, yellow (Y), magenta (M), cyan (C), and black (Bk). - Each
image forming unit 600 includes a rotatablephotosensitive drum 1, which serves as an image bearing member. Moreover, eachimage forming unit 600 further includes a chargingroller 2 serving as a charging unit, adevelopment device 3 serving as a development unit, aprimary transfer roller 4 serving as a primary transfer unit, and aphotosensitive member cleaner 5 serving as a photosensitive member cleaning unit, which are arranged along the rotational direction of thephotosensitive drum 1. - Each
development device 3 is detachably attached to theimage forming apparatus 60. Eachdevelopment device 3 includes adeveloper container 50, which contains a two-component developer (hereinafter referred to simply as a "developer") including non-magnetic toner (hereinafter referred to simply as "toner") and magnetic carrier. Moreover, toner cartridges in which toners of respective colors, Y, M, C, and Bk, are respectively contained are detachably attached to theimage forming apparatus 60. Toners of respective colors, Y, M, C, and Bk, are supplied to therespective developer containers 50 via toner conveyance paths. Furthermore, details of thedevelopment device 3 are described below with reference toFig. 2 to Fig. 4 , and details of thedeveloper container 50 are described below with reference toFig. 5 . - The
intermediate transfer belt 61 is supported by atension roller 6, a drivenroller 7a, aprimary transfer roller 4, a drivenroller 7b, and a secondary transferinner roller 66 to extend in a tensioned state, and is driven to be conveyed in the direction of arrow C inFig. 1 . The secondary transferinner roller 66 also serves as a driving roller used to drive theintermediate transfer belt 61. In conjunction with rotation of the secondary transferinner roller 66, theintermediate transfer belt 61 rotates in the direction of arrow C inFig. 1 . - The
intermediate transfer belt 61 is pressed by theprimary transfer roller 4 from the back side of theintermediate transfer belt 61. Moreover, theintermediate transfer belt 61 abutting on thephotosensitive drum 1 forms a primary transfer nip portion serving as a primary transfer portion between thephotosensitive drum 1 and theintermediate transfer belt 61. - An intermediate
transfer member cleaner 8 serving as a belt cleaning unit abuts on a position opposite to thetension roller 6 via theintermediate transfer belt 61. Moreover, a secondary transferouter roller 67 serving as a secondary transfer unit is arranged at a position opposite to the secondary transferinner roller 66 via theintermediate transfer belt 61. Theintermediate transfer belt 61 is sandwiched between the secondary transferinner roller 66 and the secondary transferouter roller 67. With this, a secondary transfer nip portion serving as a secondary transfer portion is formed between the secondary transferouter roller 67 and theintermediate transfer belt 61. At the secondary transfer nip portion, imparting a predetermined pressure and a predetermined transfer bias (electrostatic load bias) causes a toner image to adhere to the surface of a sheet S (for example, paper or plastic film). - Sheets S are stored in the state of being stacked in a sheet storing portion 62 (for example, a feed cassette or a feed deck) . A
feed unit 63 feeds a sheet S in conformity with image forming timing with use of, for example, a friction separation method using, for example, a feed roller. The sheet S fed by thefeed unit 63 is conveyed to aregistration roller 65, which is located on the way of aconveyance path 64. After being subjected to skew correction and timing correction at theregistration roller 65, the sheet S is conveyed to the secondary transfer nip portion. At the secondary transfer nip portion, the sheet S and the toner image coincide in timing with each other, so that secondary transfer is performed. - A fixing
device 9 is arranged at the more downstream side in the conveyance direction of the sheet S than the secondary transfer nip portion. Imparting a predetermined pressure and a predetermined amount of heat from the fixingdevice 9 to the sheet S conveyed to thefixing device 9 causes the toner image to be fused and fixed onto the surface of the sheet S. The sheet S with an image fixed thereto in this way is directly discharged to adischarge tray 601 according to the forward rotation of adischarge roller 69. - In the case of performing two-sided image formation, after the sheet S is conveyed until the trailing edge of the sheet S passes through a
diverter 602 according to the forward rotation of thedischarge roller 69, thedischarge roller 69 is rotated backward. With this, the leading and trailing edges of the sheet S are switched, so that the sheet S is conveyed to a two-sided conveyance path 603. After that, in conformity with next image forming timing, the sheet S is re-conveyed by are-feed roller 604 to theconveyance path 64. - During image formation, the
photosensitive drum 1 is driven to rotate by a motor. The chargingroller 2 uniformly charges the surface of thephotosensitive drum 1, which is being driven to rotate, in advance. Anexposure device 68 forms an electrostatic latent image on the surface of thephotosensitive drum 1 charged by the chargingroller 2, based on a signal of image information input to theimage forming apparatus 60. Thephotosensitive drum 1 allows a plurality of sizes of electrostatic latent images to be formed thereon. - The
development device 3 includes a rotatable developingsleeve 70, which serves a developer bearing member that bears (e.g. carries) a developer. Thedevelopment device 3 develops an electrostatic latent image formed on the surface of thephotosensitive drum 1 with use of a developer borne (e.g. carried) on the surface of the developingsleeve 70. With this, toner adheres to an exposure portion on the surface of thephotosensitive drum 1, so that a visible image appears thereon. A transfer bias (electrostatic load bias) is imparted to theprimary transfer roller 4, so that a toner image formed on the surface of thephotosensitive drum 1 is transferred onto theintermediate transfer belt 61. Toner slightly remaining on the surface of thephotosensitive drum 1 after primary transfer (transfer residual toner) is recovered by thephotosensitive member cleaner 5, and is then re-prepared for a next image formation process. - Image formation processes for respective colors, which are parallelized by the
image forming units 600 for respective colors, Y, M, C, and Bk, are performed at timing in which a next toner image is sequentially superposed on a toner image for the upstream color primarily transferred on theintermediate transfer belt 61. As a result, a full-color toner image is formed on theintermediate transfer belt 61, so that the toner image is conveyed to the secondary transfer nip portion. A transfer bias is imparted to the secondary transferouter roller 67, so that the toner image formed on theintermediate transfer belt 61 is transferred to the sheet S conveyed to the secondary transfer nip portion. Toner slightly remaining on theintermediate transfer belt 61 after the sheet S passes through the secondary transfer nip portion (transfer residual toner) is recovered by the intermediatetransfer member cleaner 8. The fixingdevice 9 fixes the toner image transferred onto the sheet S. The sheet (recording medium) S subjected to fixing processing by the fixingdevice 9 is discharged to thedischarge tray 601. - The above-described series of operations of an image forming process ends, and a next image forming operation is prepared.
- Next, a configuration of the
development device 3 according to the first exemplary embodiment of the invention is described with reference to the perspective view ofFig. 2 , the perspective view ofFig. 3 , and the sectional view ofFig. 4. Fig. 4 is a sectional view of thedevelopment device 3 illustrating a cross-section H inFig. 2 . - The
development device 3 includes adeveloper container 50 configured with a development frame member made of resin, which is molded with resin (hereinafter referred to simply as a "development frame member 30"), and a cover frame member made of resin, which is molded with resin (hereinafter referred to simply as a "cover frame member 40"), which is formed separately from thedevelopment frame member 30.Fig. 2 andFig. 4 illustrate a state in which thecover frame member 40 is attached to thedevelopment frame member 30, andFig. 3 illustrates a state in which thecover frame member 40 is not attached to thedevelopment frame member 30. Furthermore, details of the configuration of the development frame member 30 (single body) are described below with reference toFig. 5 . - The
developer container 50 is provided with an aperture at a position equivalent to a development region in which the developingsleeve 70 faces thephotosensitive drum 1. The developingsleeve 70 is arranged to be rotatable relative to thedeveloper container 50 in such a manner that a part of the developingsleeve 70 is exposed on the aperture of thedeveloper container 50. A bearing 71 serving as a bearing member is provided at each of both end portions of the developingsleeve 70. - The inside of the
developer container 50 is sectioned by apartition wall 38, which extends in vertical direction, into adevelopment chamber 31 serving as a first chamber and anagitation chamber 32 serving as a second chamber. Thedevelopment chamber 31 and theagitation chamber 32 are connected with each other at both ends in the longitudinal direction thereof viacommunication portions 39 provided at two locations of thepartition wall 38. Therefore, a developer is allowed to be transmitted between thedevelopment chamber 31 and theagitation chamber 32 via thecommunication portions 39. Thedevelopment chamber 31 and theagitation chamber 32 are arranged horizontally side by side with respect to the horizontal direction. - A magnet roll having a plurality of magnetic poles along the rotational direction of the developing
sleeve 70 and serving as a magnetic field generation unit that generates a magnetic field for causing the surface of the developingsleeve 70 to bear (e.g. carry) a developer thereon is fixedly arranged inside the developingsleeve 70. A developer in thedevelopment chamber 31 is drawn up under the influence of a magnetic field caused by the magnetic poles of the magnet roll, and is thus supplied to the developingsleeve 70. Since a developer is supplied from thedevelopment chamber 31 to the developingsleeve 70 in this way, thedevelopment chamber 31 is also referred to as a "supply chamber". - Inside the
development chamber 31, afirst conveyance screw 33, which serves as a conveyance unit that agitates a developer in thedevelopment chamber 31 and conveys the developer, is arranged opposite the developingsleeve 70. Thefirst conveyance screw 33 includes arotation shaft 33a, which serves as a rotatable shaft portion, and aspiral blade portion 33b, which serves as a developer conveyance portion, provided along the outer circumference of therotation shaft 33a, and is supported in such a way as to be rotatable relative to thedeveloper container 50. A bearing member is provided at each of both end portions of therotation shaft 33a. - Moreover, inside the
agitation chamber 32, asecond conveyance screw 34, which serves as a conveyance unit that agitates a developer in theagitation chamber 32 and conveys the developer in a direction opposite to that of thefirst conveyance screw 33, is arranged. Thesecond conveyance screw 34 includes arotation shaft 34a, which serves as a rotatable shaft portion, and aspiral blade portion 34b, which serves as a developer conveyance portion, provided along the outer circumference of therotation shaft 34a, and is supported in such a way as to be rotatable relative to thedeveloper container 50. A bearing member is provided at each of both end portions of therotation shaft 34a. Then, when thefirst conveyance screw 33 and thesecond conveyance screw 34 are driven to rotate, a developer is caused to circulate between thedevelopment chamber 31 and theagitation chamber 32 via thecommunication portions 39. - A regulating blade, which serves as a developer regulating member that regulates the amount of a developer borne on the surface of the developing sleeve 70 (also referred to as a "developer coated amount") (hereinafter referred to as a "
doctor blade 36"), is attached to thedeveloper container 50 while being arranged opposite the surface of the developingsleeve 70 in a non-contact manner therewith. Thedoctor blade 36 has a coatedamount regulating surface 36r (i.e. regulating portion or regulating surface), which serves as a regulating portion used to regulate the amount of a developer borne on the surface of the developingsleeve 70. Thedoctor blade 36 is a doctor blade made of resin, which is molded with resin. Furthermore, a configuration of the doctor blade 36 (single body) is described below with reference toFig. 6 . - The
doctor blade 36 is arranged opposite the developingsleeve 70 via a predetermined gap (hereinafter referred to as an "SB gap G") between thedoctor blade 36 and the developingsleeve 70 over the longitudinal direction of the developing sleeve 70 (i.e., a direction parallel to the direction of a rotational axis of the developing sleeve 70). That is, for example, the predetermined gap separates thedoctor blade 36 and the developingsleeve 70. Preferably, the predetermined gap separates thedoctor blade 36 from the developingsleeve 70 by a fixed amount along the length of thedoctor blade 36. It will be appreciated that the length axis of thedoctor blade 36 is preferably parallel with the length of the axis of the developingsleeve 70. The developingsleeve 70 is preferably arranged to rotate about its length axis. In the context of the present specification, the SB gap G preferably refers to the shortest distance between a region corresponding to a maximum image region which the developingsleeve 70 is able to form on the surface of the photosensitive drum 1 (in other words, a maximum image region of the developing sleeve 70) and a region of thedoctor blade 36 corresponding to the maximum image region (in other words, a maximum image region of the doctor blade 36). In the first exemplary embodiment, since thephotosensitive drum 1 is allowed to form a plurality of sizes of electrostatic latent images thereon, the maximum image region is assumed to refer to an image region corresponding to the largest size (for example, A3 size) among a plurality of sizes of electrostatic latent images able to be formed on thephotosensitive drum 1. On the other hand, in a modification example in which thephotosensitive drum 1 is allowed to form only one size of electrostatic latent image thereon, the maximum image region is assumed to instead refer to an image region corresponding to only one size of image able to be formed on thephotosensitive drum 1. - The
doctor blade 36 may be arranged approximately/substantially opposite the peak position of a magnetic flux density of magnetic poles of the magnet roll. A developer supplied to the developingsleeve 70 is affected by a magnetic field caused by the magnetic poles of the magnet roll. Moreover, a developer regulated and scraped by thedoctor blade 36 tends to stagnate (e.g. decay) at the upstream portion of the SB gap G. As a result, a developer stagnation is formed at the more upstream side in the rotational direction of the developingsleeve 70 than thedoctor blade 36. That is, the amount of developer at the ends of thedevelopment sleeve 70 may be reduced (as compared to the center of the development sleeve 70) as a result of the doctor blade scraping thedevelopment sleeve 70. The doctor blade scrapes thedevelopment sleeve 70 to regulate the amount of developer on it. Consequently, a partial developer of the developer stagnation is conveyed in such a way as to pass through the SB gap G according to the rotation of the developingsleeve 70. At this time, the layer thickness of a developer passing through the SB gap G is regulated by the coatedamount regulating surface 36r of thedoctor blade 36. In this way, a thin layer of developer is formed on the surface of the developingsleeve 70. - Then, a predetermined amount of developer borne on the surface of the developing
sleeve 70 is conveyed to a development region according to the rotation of the developingsleeve 70. Therefore, adjusting the size of the SB gap G leads to adjusting the amount of a developer to be conveyed to the development region. In the first exemplary embodiment, a size of the SB gap G targeted to adjust the size of the SB gap G (in other words, a target value of the SB gap G) is set to about 300 micrometers (µm). - The developer conveyed to the development region is magnetically lifted at the development region, so that a magnetic brush is formed. The magnetic brush contacting the
photosensitive drum 1 causes toner contained in the developer to be supplied to thephotosensitive drum 1. Then, an electrostatic latent image formed on the surface of thephotosensitive drum 1 is developed as a toner image. A developer on the surface of the developingsleeve 70 remaining after passing the development region and supplying toner to the photosensitive drum 1 (hereinafter referred to as a "developer after development process") is peeled from the surface of the developingsleeve 70 by a repulsive magnetic field formed between magnetic poles of the same polarity of the magnet roll. The developer after development process peeled from the surface of the developingsleeve 70 falls in thedevelopment chamber 31, thus being recovered into thedevelopment chamber 31. - As illustrated in
Fig. 4 , thedevelopment frame member 30 is provided with adeveloper guide portion 35 for guiding a developer in such a manner that the developer is conveyed toward the SB gap G. Thedeveloper guide portion 35 and thedevelopment frame member 30 are configured to be integrally formed, and thedeveloper guide portion 35 and thedoctor blade 36 are configured to be separately formed. Thedeveloper guide portion 35 is formed inside thedevelopment frame member 30, and is arranged at the more upstream side in the rotational direction (i.e. in the anticlockwise direction as viewed inFig. 4 ) of the developingsleeve 70 than the coatedamount regulating surface 36r of thedoctor blade 36. The flow of a developer is stabilized by thedeveloper guide portion 35 to make adjustment to obtain a predetermined developer density, so that the weight of a developer at a position in which the coatedamount regulating surface 36r of thedoctor blade 36 is in most proximity to the surface of the developingsleeve 70 can be defined. - Moreover, as illustrated in
Fig. 4 , thecover frame member 40 is formed separately from thedevelopment frame member 30 and is attached to thedevelopment frame member 30. Additionally, thecover frame member 40 covers a part of the aperture of thedevelopment frame member 30 in such a manner that a part of the outer circumferential surface of the developingsleeve 70 is covered over the entirety in the longitudinal direction of the developingsleeve 70. At this time, thecover frame member 40 covers a part of the aperture of thedevelopment frame member 30 in such a manner that a development region facing thephotosensitive drum 1 of the developingsleeve 70 is exposed. While, in the first exemplary embodiment, thecover frame member 40 is fixed to thedevelopment frame member 30 by ultrasonic adhesion, the method of fixing thecover frame member 40 to thedevelopment frame member 30 can be any method, such as screw fastening, snap fit, adhesion, or welding. - Next, a configuration of the development frame member 30 (single body) is described with reference to the perspective view of
Fig. 5. Fig. 5 illustrates a state in which thecover frame member 40 is not attached to thedevelopment frame member 30. - The
development frame member 30 includes thedevelopment chamber 31 and theagitation chamber 32, which is separated from thedevelopment chamber 31 via the partition wall 38 (seeFig. 4 ). Thepartition wall 38 is molded with resin, and can be configured to be formed separately from thedevelopment frame member 30 or can be formed integrally with thedevelopment frame member 30. - The
development frame member 30 hassleeve supporting portions 42 configured to support the developingsleeve 70 in such a way as to allow the developingsleeve 70 to rotate by supportingbearings 71 respectively provided at both end portions of the developing sleeve 70 (seeFigs. 3 ,4 and5 ). Moreover, thedevelopment frame member 30 has a blade attaching portion 41 (which is formed integrally with the sleeve supporting portions 42) to which thedoctor blade 36 is attached.Fig. 5 illustrates a virtual state in which thedoctor blade 36 floats above theblade attaching portion 41. - In the first exemplary embodiment, with the
doctor blade 36 attached to theblade attaching portion 41, an adhesive A applied to ablade attaching surface 41s of theblade attaching portion 41 becomes hardened, so that thedoctor blade 36 is fixed to the blade attaching portion 41 (SeeFig. 4 ). Details of the method of fixing thedoctor blade 36 to theblade attaching portion 41 are described below with reference toFig. 9 and subsequent figures. - According to an increase in the width of the sheet S on which an image is to be formed, for example, the width of the sheet S being A3 size, the area of a coated amount regulating surface corresponding to the maximum image region able to be formed on the surface of the
photosensitive drum 1 becomes larger, so that the length in the longitudinal direction of a doctor blade becomes larger. - In a case where the length of the doctor blade (note the length extends along the longitudinal axis of the doctor blade) is large, and the doctor blade is molded with resin, it is difficult to ensure the straightness/uniformity of the blade with a coated amount regulating surface provided for the doctor blade made of resin, which is molded with resin. This is because, when a doctor blade the length in the longitudinal direction of which is large is molded with resin, variations are likely to occur in ratios in which thermally-expanded resin thermally contracts. Furthermore, the straightness of a coated amount regulating surface is represented by the absolute value of a difference between the maximum value and minimum value of the outer shape of a coated amount regulating surface based on a predetermined location on the coated amount regulating surface in the longitudinal direction of the coated amount regulating surface. For example, suppose that a central portion of the coated amount regulating surface in the longitudinal direction of the coated amount regulating surface is set as the origin, a predetermined straight line passing through the origin is set as the X-axis, and a straight line drawn from the origin in a direction perpendicular to the X-axis is set as the Y-axis. In this orthogonal coordinate system, the straightness of a coated amount regulating surface is represented by the absolute value of a difference between the maximum value and minimum value of the Y-coordinate of the outer shape of the coated amount regulating surface.
- For example, in a case where a doctor blade made of resin the length in the longitudinal direction of which is a length corresponding to A3 size (hereinafter referred to as a "doctor blade made of resin compatible with A3 size") is manufactured with the accuracy of a general resin product, the straightness of a coated amount regulating surface is approximately 300 µm to 500 µm. Moreover, even if the doctor blade made of resin compatible with A3 size is manufactured with a high degree of accuracy with use of a high-precision resin material, the straightness of a coated amount regulating surface is approximately 100 µm to 200 µm.
- Therefore, in the case of a doctor blade made of resin, as the length in the longitudinal direction of the doctor blade become larger, the SB gap is more likely to vary along the longitudinal direction (i.e. along the longitudinal axis) of the developer bearing member due to the straightness of a coated amount regulating surface - e.g. the size of the SB gap separating the doctor blade from the development sleeve may vary along the length (i.e. along the longitudinal axis) of the development sleeve/doctor blade due to variations/non-uniformities in the straightness of the doctor blade. In particular, unevenness in the straightness of the regulating surface of the doctor blade can cause variations in the size of the SB gap. If the SB gap varies in/along the longitudinal direction/axis of a developer bearing member, unevenness may occur in the amount of a developer to be borne on the surface of the developer bearing member in the longitudinal direction of the developer bearing member.
- Therefore, in the first exemplary embodiment, to prevent or reduce unevenness in the amount of a developer to be borne on the surface of the developing
sleeve 70 in/along the longitudinal direction/axis of the developingsleeve 70, the SB gap G is configured to be within a predetermined range over the longitudinal direction/axis of the developingsleeve 70. Specifically, in the first exemplary embodiment, the tolerance of the SB gap G (in other words, a tolerance of the SB gap G relative to a target value) is set to ±10% or less, so that the SB gap G falls within a predetermined range over the longitudinal direction of the developingsleeve 70. - In the first exemplary embodiment, a method described as follows is used to determine whether the SB gap G is within a predetermined range over the longitudinal direction of the developing
sleeve 70. Furthermore, details of a method of measuring the SB gap G (calculation method) are described below with reference toFig. 11 . - First, an area corresponding to the maximum image region of the
doctor blade 36 is divided into four or more locations at even intervals, and the SB gap G is measured at five or more locations in each of the divided locations of the doctor blade 36 (in this regard, including both end portions and a central portion of the area corresponding to the maximum image region of the doctor blade 36). Then, the maximum value of the SB gap G, the minimum value of the SB gap G, and the median value of the SB gap G are extracted from samples of measured values of the SB gap G measured at five or more locations. If (i) the absolute value of a difference between the maximum value of the SB gap G and the median value of the SB gap G is 10% or less of the median value of the SB gap G, and (ii) the absolute value of a difference between the minimum value of the SB gap G and the median value of the SB gap G is 10% or less of the median value of the SB gap G, then it is acceptable. In this case, the tolerance of the SB gap G is assumed to be ±10% or less and the SB gap G is assumed to satisfy being within a predetermined range over the longitudinal direction of the developingsleeve 70. - For example, in a case where the median value of the SB gap G is 300 µm based on samples of measured values of the SB gap G measured at five or more locations, if the maximum value of the SB gap G is 330 µm or less and the minimum value of the SB gap G is 270 µm or more, then it is acceptable. In other words, in this case, it is meant that the adjustment value of the SB gap G is 300 µm ± 30 µm and the allowable tolerance of the SB gap G is up to 60 µm. Therefore, even if a doctor blade made of resin compatible with A3 size is manufactured with the precision of a general resin product or can be manufactured with a high degree of accuracy with use of a high-precision resin material, the range allowable as the tolerance of the SB gap G would be exceeded only with the precision of the straightness of a coated amount regulating surface.
- Therefore, in the case of a development device equipped with a doctor blade made of resin, the SB gap G is desired to be within a predetermined range over the longitudinal direction (i.e. over the longitudinal axis or length) of a developer bearing member in a state that the doctor blade is fixed to the blade attaching portion of the development frame member, regardless of the straightness of a coated amount regulating surface. The first exemplary embodiment employs a configuration described below in such a manner that, even when a doctor blade made of resin, in which the accuracy of the straightness of a coated amount regulating surface is low, is used, a gap between the developer bearing member and the doctor blade is made to be within a predetermined range over the longitudinal direction (i.e. over the longitudinal axis or length) of the developer bearing member in a state that the doctor blade is fixed to the blade attaching portion of the development frame member. Details thereof are described as follows.
- First, a configuration of the doctor blade 36 (single body) is described with reference to the perspective view of
Fig. 6 . - During an image forming operation (development operation), the pressure of a developer (hereinafter referred to as "developer pressure"), which occurs due to the flow of the developer, is imparted to the
doctor blade 36. As the rigidity of thedoctor blade 36 is smaller, when the developer pressure is imparted to thedoctor blade 36 during an image forming operation (development operation), thedoctor blade 36 is more likely to become deformed, so that the size of the SB gap G is more likely to vary. During an image forming operation (development operation), the developer pressure is imparted in the widthwise direction of the doctor blade 36 (i.e. the direction of arrow M inFig. 6 , which is perpendicular to the length of the doctor blade 36). Therefore, to prevent or reduce variations in the size of the SB gap G in the process of an image forming operation (development operation), it is desirable that the rigidity in the widthwise direction of thedoctor blade 36 be increased to strengthen thedoctor blade 36 against deformation in the widthwise direction thereof. - As illustrated in
Fig. 6 , in the first exemplary embodiment, the shape of thedoctor blade 36 is made platelike from the viewpoint of mass productivity and cost. Moreover, as illustrated inFig. 6 , in the first exemplary embodiment, the cross-sectional area of aside surface 36t of thedoctor blade 36 is made small, and, additionally, the length t2 in the thickness direction of thedoctor blade 36 is made smaller than the length t1 in the widthwise direction of the doctor blade 36 (i.e. the thickness t2 of thedoctor blade 36 is made smaller than the width t1 of the doctor blade 36). With this, the doctor blade 36 (single body) is configured to easily deform in a direction (the direction of arrow M inFig. 6 ) perpendicular to the longitudinal direction of the doctor blade 36 (the direction of arrow N inFig. 6 ) - i.e. the doctor blade is configured to preferably deform along the widthwise axis of the doctor blade 36). Therefore, to correct the straightness of the coatedamount regulating surface 36r, the first exemplary embodiment employs a method of fixing thedoctor blade 36 to theblade attaching portion 41 of thedevelopment frame member 30 in a state in which at least a part of thedoctor blade 36 is warped in/along the direction of arrow M inFig. 6 . Furthermore, details of the method of fixing thedoctor blade 36 to theblade attaching portion 41 of the development frame member 30 (hereinafter referred to as a "fixation method for thedoctor blade 36") are described below with reference toFig. 9 and subsequent figures. - Next, the rigidity of the doctor blade 36 (single body) is described with reference to the schematic view of
Fig. 7 . The rigidity of the doctor blade 36 (single body) is measured in a state in which thedoctor blade 36 is not fixed to theblade attaching portion 41 of thedevelopment frame member 30. - As illustrated in
Fig. 7 , a concentrated load F1 is imparted in the widthwise direction of thedoctor blade 36 to acentral portion 36z of thedoctor blade 36 as viewed in the longitudinal direction of thedoctor blade 36. At this time, the rigidity of the doctor blade 36 (single body) is measured based on the amount of warp in the widthwise direction of thedoctor blade 36 at thecentral portion 36z of thedoctor blade 36. - For example, suppose that a concentrated load F1 of 300 gram-force (gf) is imparted in the widthwise direction of the
doctor blade 36 to thecentral portion 36z of thedoctor blade 36 as viewed in the longitudinal direction of the doctor blade 36 (i.e. load F1 is applied to thecentral portion 36z of thedoctor blade 36 and thecentral portion 36z is located in the middle of the doctor blade's length). At this time, the amount of warp in the widthwise direction of thedoctor blade 36 at thecentral portion 36z of thedoctor blade 36 is 700 µm or more. Furthermore, at this time, the amount of deformation of thecentral portion 36z of thedoctor blade 36 on the cross-section is 5 µm or less. It will be noted that the amount of warp/deformation is preferably determined relative to when no force is applied to thedoctor blade 36. - Next, the rigidity of the development frame member 30 (single body) is described with reference to the schematic view of
Fig. 8 . The rigidity of the development frame member 30 (single body) is measured in a state in which thedoctor blade 36 is not fixed to theblade attaching portion 41 of thedevelopment frame member 30. - As illustrated in
Fig. 8 , a concentrated load F1 is imparted in the widthwise direction of theblade attaching portion 41 to acentral portion 41z of theblade attaching portion 41 as viewed in the longitudinal direction of theblade attaching portion 41. At this time, the rigidity of the development frame member 30 (single body) is measured based on the amount of warp in the widthwise direction of theblade attaching portion 41 at thecentral portion 41z of theblade attaching portion 41. - For example, suppose that a concentrated load F1 of 300 gf is imparted in the widthwise direction of the
blade attaching portion 41 to thecentral portion 41z of theblade attaching portion 41 as viewed in the longitudinal direction of theblade attaching portion 41. At this time, the amount of warp in the widthwise direction of theblade attaching portion 41 at thecentral portion 41z of theblade attaching portion 41 is 60 µm or less. - Suppose that the concentrated load F1 of the same magnitude is imparted to each of the
central portion 36z of thedoctor blade 36 and thecentral portion 41z of theblade attaching portion 41 of thedevelopment frame member 30. At this time, the amount of warp of thecentral portion 36z of thedoctor blade 36 is 10 times or more the amount of warp of thecentral portion 41z of theblade attaching portion 41. Thus, the magnitude of the rigidity of the development frame member 30 (single body) is at least 10 times larger than the magnitude of the rigidity of the doctor blade 36 (single body). Therefore, in a state in which thedoctor blade 36 is attached to theblade attaching portion 41 of thedevelopment frame member 30 so that thedoctor blade 36 is fixed to theblade attaching portion 41 of thedevelopment frame member 30, the rigidity of thedevelopment frame member 30 becomes more dominant than the rigidity of thedoctor blade 36. - Moreover, the magnitude of the rigidity of the development frame member 30 (single body) is larger than the magnitude of the rigidity of the cover frame member 40 (single body). Therefore, in a state in which the
cover frame member 40 is attached to thedevelopment frame member 30 so that thecover frame member 40 is fixed to thedevelopment frame member 30, the rigidity of thedevelopment frame member 30 becomes more dominant than the rigidity of thecover frame member 40. - Each of steps of the fixation method for the
doctor blade 36 is described with reference to the schematic views ofFig. 9 to Fig. 14 . An external apparatus (hereinafter referred to simply as an "apparatus 100") performs each of steps of the fixation method for thedoctor blade 36 described as follows. - First, the
apparatus 100 detects the outer shape of the coatedamount regulating surface 36r of thedoctor blade 36. Next, theapparatus 100 recognizes the straightness of the coatedamount regulating surface 36r based on a central portion of the coatedamount regulating surface 36r (a front edge portion 36e3 of the doctor blade 36) with regard to the outer shape of the coatedamount regulating surface 36r in the longitudinal direction of the coatedamount regulating surface 36r. In the steps of the fixation method for thedoctor blade 36, a doctor blade made of resin compatible with A3 size manufactured with the accuracy of a general resin product is used. Therefore, theapparatus 100 recognizes that the straightness of the coatedamount regulating surface 36r is approximately 300 µm to 500 µm. Then, theapparatus 100 warps at least a part of the area corresponding to the maximum image region of thedoctor blade 36 with a force imparted to thedoctor blade 36. Then, theapparatus 100 corrects the straightness of the coatedamount regulating surface 36r to 50 µm or less (hereinafter referred to as a "warping step"). - Next, the
apparatus 100 determines a position at which to fix thedoctor blade 36, at least a part of the area corresponding to the maximum image region of which has been warped in the warping step, to theblade attaching portion 41 of thedevelopment frame member 30 so as to cause the SB gap G to fall within a predetermined range (hereinafter referred to as a "positioning step"). Next, in a state in which at least a part of the area corresponding to the maximum image region of thedoctor blade 36 has been warped, theapparatus 100 fixes a part of the area corresponding to the maximum image region of thedoctor blade 36 at a predetermined position of theblade attaching portion 41 determined in the positioning step (hereinafter referred to as a "fixation step"). - The
apparatus 100 includes aplacement board 103 on which to place the doctor blade 36 (single body). Moreover, theapparatus 100 further includes fingers 101 (101p1 to 101p5) provided at five locations to grasp the respective grab portions 37 (37P1 to 37p5) provided at five locations in the area corresponding to the maximum image region of thedoctor blade 36. Each of the fingers 101 (101p1 to 101p5) is independently movable along the direction J inFig. 9 , and is able to move forward and move backward with respect to the direction J inFig. 9 . - Moreover, the
apparatus 100 further includes cameras 102 (102p1 to 102p5) provided at five locations to measure the respective positions offront edge portions 36e (36e1 to 36e5) provided at five locations included in the coatedamount regulating surface 36r of thedoctor blade 36. Each of the cameras 102 (102p1 to 102p5) is arranged along a direction toward a corresponding one of thefront edge portions 36e (36e1 to 36e5) of the doctor blade 36 (the direction of arrow F inFig. 9 ). Then, the cameras 102 (102p1 to 102p5) detect the outer shape of the coatedamount regulating surface 36r of thedoctor blade 36 by measuring the positions of thefront edge portions 36e (36e1 to 36e5) of thedoctor blade 36. Next, theapparatus 100 recognizes the straightness of the coatedamount regulating surface 36r based on the central portion of the coatedamount regulating surface 36r (the front edge portion 36e3 of the doctor blade 36) with regard to the outer shape of the coatedamount regulating surface 36r in the longitudinal direction of the coatedamount regulating surface 36r. Furthermore, while an example in which the measurement of the positions of thefront edge portions 36e (36e1 to 36e5) of thedoctor blade 36 is performed by the cameras 102 (102p1 to 102p5) is hereinafter described, a modification example in which the measurement is performed by non-contact sensors can be employed. - The
doctor blade 36 is manufactured with the precision of a general resin product. As mentioned above, in a case where the doctor blade made of resin compatible with A3 size is manufactured with the precision of a general resin product, the straightness of a coated amount regulating surface is approximately 300 µm to 500 µm. Suppose that thedoctor blade 36 is a doctor blade made of resin compatible with A3 size which is manufactured with the precision of a general resin product. In this case, in a state in which thedoctor blade 36 is placed on theplacement board 103, when the positions of thefront edge portions 36e (36e1 to 36e5) provided at five locations of thedoctor blade 36 are measured by the cameras 102 (102p1 to 102p5), a difference of approximately 300 µm to 500 µm would be detected. On the other hand, as mentioned above, the tolerance of the SB gap G is set to ±10% or less so as to prevent or reduce unevenness in the amount of a developer to be borne on the surface of the developingsleeve 70 in the longitudinal direction of the developingsleeve 70. - Therefore, in view of, for example, the allowable value of the tolerance of the SB gap G or the attaching accuracy of the
doctor blade 36 to thedevelopment frame member 30, the straightness of thefront edge portions 36e (36e1 to 36e5) of the doctor blade 36 (in other words, the straightness of the coatedamount regulating surface 36r) is required to be corrected to 50 µm or less. Furthermore, in view of the fact that the accuracy of the straightness of a doctor blade made of metal manufactured by secondary cutting work is 20 µm or less, it is more desirable that the straightness of the coatedamount regulating surface 36r of thedoctor blade 36 made of resin be corrected to 20 µm or less. - Next, details of a series of steps of the fixation method for the doctor blade 36 (a warping step, a positioning step, and a fixation step) are hereinafter described.
- First, details of the warping step are described with reference to the schematic view of
Fig. 9 . Theapparatus 100 holds thedoctor blade 36 by grasping the grab portions 37 (37P1 to 37p5) of thedoctor blade 36 with the fingers 101 (101p1 to 101p5). Next, the cameras 102 (102p1 to 102p5) measure the positions of thefront edge portions 36e (36e1 to 36e5) of thedoctor blade 36 with the grab portions 37 (37P1 to 37p5) of thedoctor blade 36 grasped with the fingers 101 (101p1 to 101p5). With this, theapparatus 100 detects the outer shape of the coatedamount regulating surface 36r of thedoctor blade 36. Next, theapparatus 100 recognizes the straightness of the coatedamount regulating surface 36r based on the central portion of the coatedamount regulating surface 36r (the front edge portion 36e3 of the doctor blade 36) with regard to the outer shape of the coatedamount regulating surface 36r in the longitudinal direction of the coatedamount regulating surface 36r. - Then, the
apparatus 100 moves each of the fingers 101 (101p1 to 101p5) in the direction J inFig. 9 with the grab portions 37 (37P1 to 37p5) of thedoctor blade 36 grasped with thefingers 101. With this, theapparatus 100 imparts, to thedoctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of thedoctor blade 36 via thegrab portions 37 of thedoctor blade 36 grasped with thefingers 101. Thus, thegrab portions 37 of thedoctor blade 36 function as a force receiving portion for receiving a force imparted from theapparatus 100 to thedoctor blade 36 to warp at least a part of the area corresponding to the maximum image region of thedoctor blade 36. - As illustrated in
Fig. 10 , the doctor blade 36 (single body) has such a shape that the central portion of the coatedamount regulating surface 36r of thedoctor blade 36 is greatly warped in/along the longitudinal direction of the doctor blade 36 - that is the widthwise profile of thedoctor blade 36 varies along the longitudinal axis/length of thedoctor blade 36. Therefore, it is necessary to correct the straightness of the coatedamount regulating surface 36r of thedoctor blade 36 by reducing differences of positions of thefront edge portions 36e (36e1 to 36e5) of thedoctor blade 36. Thus, a method of reducing differences of positions of thefront edge portions 36e (36e1 to 36e5) of thedoctor blade 36 based on a result of detection of the positions of thefront edge portions 36e (36e1 to 36e5) of the doctor blade 36 (the detected outer shape of the coatedamount regulating surface 36r) is employed. For that purpose, theapparatus 100 corrects the straightness of the coatedamount regulating surface 36r to 50 µm or less by imparting, to thedoctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of the doctor blade 36 (hereinafter referred to as a "straightness correction force"). - Next, the
apparatus 100 grasps the grab portions 37 (37P1 to 37p5) of thedoctor blade 36 placed on theplacement board 103 with the fingers 101 (101p1 to 101p5). Then, theapparatus 100 independently moves forward or moves backward each of thefingers 101 along the direction of arrow J inFig. 9 while grasping the grab portions 37 (37P1 to 37p5) of thedoctor blade 36 with the fingers 101 (101p1 to 101p5). At this time, theapparatus 100 imparts, to thedoctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of thedoctor blade 36 via thegrab portions 37 of thedoctor blade 36. - In the example illustrated in
Fig. 10 , theapparatus 100 sets the outer shapes of the front edge portions 36e1 and 36e5 of thedoctor blade 36 as a base, and imparts a straightness correction force to thedoctor blade 36 in such a way as to adjust the outer shapes of the front edge portions 36e2, 36e3, and 36e4 to the base. In the example illustrated inFig. 10 , thedoctor blade 36 externally receives a force for warping at least a part of the area corresponding to the maximum image region of thedoctor blade 36 via the grab portions 37 (37P2 to 37p4) provided at three locations among five locations. Then, with the force received by thedoctor blade 36 via the grab portions 37 (37P2 to 37p4) provided at three locations, a straightness correction force for correcting the straightness of the coatedamount regulating surface 36r is imparted to the front edge portions 36e2 to 36e4 of thedoctor blade 36 in the direction of arrow I inFig. 10 . At this time, the straightness correction force is imparted to the coatedamount regulating surface 36r and, thus, a part of the area corresponding to the maximum image region of thedoctor blade 36 is warped, so that the straightness of the coatedamount regulating surface 36r of thedoctor blade 36 is corrected. In the example illustrated inFig. 10 , the shape of the coatedamount regulating surface 36r of thedoctor blade 36 is corrected from a coated amount regulating surface 36r1 to a coated amount regulating surface 36r2. - As a result, the straightness of the coated
amount regulating surface 36r of thedoctor blade 36 is able to be corrected to 50 µm or less. Furthermore, while, in the example illustrated inFig. 10 , the base used for theapparatus 100 to adjust the outer shape of thefront edge portions 36e of thedoctor blade 36 is set to the outer shapes of the front edge portions 36e1 and 36e5 of thedoctor blade 36, a modification example in which the base is set to the outer shape of the front edge portion 36e3 (in other words, a central portion of the coatedamount regulating surface 36r) can be employed. In this modification example, theapparatus 100 sets the outer shape of the front edge portion 36e3 of thedoctor blade 36 as a base, and imparts a straightness correction force to thedoctor blade 36 in such a way as to adjust the outer shapes of the front edge portions 36e1, 36e2, 36e4, and 36e5 to the base. Thus, for example, it will be seen that the widthwise profile of thedoctor blade 36 may be adjusted/warped by application of the correction force so as to straighten the widthwise profile of thedoctor blade 36. - In the first exemplary embodiment, in view of a realistic mass production process, the setting value for straightness correction of the coated
amount regulating surface 36r of thedoctor blade 36 is set to approximately 20 µm to 50 µm, and the magnitude of the straightness correction force to be imparted to thefront edge portions 36e of thedoctor blade 36 is set to about 500 g. Generally, setting the magnitude of the straightness correction force to be imparted to thefront edge portions 36e of thedoctor blade 36 smaller enables theapparatus 100 to be inexpensive and to be miniaturized. However, in a case where the magnitude of the straightness correction force to be imparted to thefront edge portions 36e of thedoctor blade 36 is too small with respect to the magnitude of the rigidity of thedoctor blade 36, it becomes impossible to correct the straightness of the coatedamount regulating surface 36r of thedoctor blade 36. Therefore, the magnitude of the straightness correction force to be imparted to thefront edge portions 36e of thedoctor blade 36 is set based on the magnitude of the rigidity of thedoctor blade 36. - In the examples illustrated in
Fig. 9 , thegrab portions 37 are provided at five locations of thedoctor blade 36. However, it will be appreciated that the locations at which thegrab portions 37 are provided on thedoctor blade 36 may be different to the locations illustrated inFig. 9 . Further, the number ofgrab portions 37 may be fewer or greater than five. In general, the number of grab portions is determined based on the non-uniformity of the widthwise profile of thedoctor blade 36 and/or how many grab portions are required to apply the necessary straight correction forces to correct the widthwise profile. Moreover, while, in the example illustrated inFig. 9 , each of thegrab portions 37 of thedoctor blade 36 is in a convex shape, the shape of each of thegrab portions 37 is not limited to that. As mentioned above, in order for theapparatus 100 to impart, to thedoctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of the doctor blade 36 (straightness correction force), thefingers 101 grasp thegrab portions 37 of thedoctor blade 36. Therefore, as long as thefingers 101 are able to grasp thegrab portions 37, the shape of each of thegrab portions 37 can be, besides a convex shape, for example, a concave shape, a groove shape, a notch shape, or a flat shape, or can be a combination of some of such shapes. Furthermore, of the drawings for the present specification, except forFig. 9 to Fig. 12 , the figures in which thedoctor blade 36 is illustrated omit thegrab portions 37 of thedoctor blade 36 from illustration. - Next, details of the positioning step are described with reference to the schematic diagrams of
Fig. 11 andFig. 12 . As illustrated inFig. 11 andFig. 12 , the positioning step is performed in a state in which the developingsleeve 70 is supported by thesleeve supporting portions 42 of thedevelopment frame member 30. - The fingers 101 (101p1 to 101p5) move the
doctor blade 36 from theplacement board 103 to theblade attaching portion 41 while holding thedoctor blade 36 kept in a warped state in the warping step (in other words, in a state in which the straightness of the coatedamount regulating surface 36r has been corrected). Furthermore, the amount of movement and the direction of movement of the fingers 101 (101p1 to 101p5) are previously set according to a program. The fingers 101 (101p1 to 101p5) are driven by actuators and operate according to the previously-set program. - Then, in a state in which the fingers 101 (101p1 to 101p5) grasp the
grab portions 37 of thedoctor blade 36 kept in a warped state in the warping step, theapparatus 100 moves thedoctor blade 36 kept in a warped state to theblade attaching portion 41 of thedevelopment frame member 30. Next, theapparatus 100 attaches thedoctor blade 36 kept in a warped state to theblade attaching portion 41. At this time, thedoctor blade 36 kept in a warped state enters a state of landing on (also referred to as a "state of abutting on") ablade attaching surface 41s (seeFig. 4 andFig. 5 ) of thedevelopment frame member 30. -
Fig. 11 illustrates a state in which thedoctor blade 36 has been caused to land on theblade attaching surface 41s while the grab portions 37 (37P1 to 37p5) of thedoctor blade 36 kept in a warped state are grasped by the fingers 101 (101p1 to 101p5). - As mentioned above, to prevent or reduce unevenness of the amount of a developer borne on the surface of the developing
sleeve 70 in the longitudinal direction of the developingsleeve 70, the range of a tolerance of the SB gap G (in other words, a range allowed as a tolerance with respect to a target value of the SB gap G) is set to approximately 60 µm. Since the range of a tolerance of the SB gap G is severe in this way, if thedoctor blade 36 is only caused to land on theblade attaching surface 41s of thedevelopment frame member 30, the SB gap G is unlikely to fall within an adjustment range of the SB gap G with the range of a tolerance of the SB gap G taken into consideration (in this regard, the adjustment range of the SB gap G including a target value of the SB gap G). Therefore, it is necessary to make an adjustment such that the SB gap G falls within an adjustment range of the SB gap G, by determining a position at which to fix thedoctor blade 36 to theblade attaching surface 41s of thedevelopment frame member 30 in such a manner that the SB gap G falls within the range of a tolerance. - The
apparatus 100 includes cameras 104 (104p1 to 104p5) provided at five locations to respectively measure the positions of thefront edge portions 36e (36e1 and 36e5) provided at five locations of thedoctor blade 36 caused to land on theblade attaching surface 41s of thedevelopment frame member 30 by thefingers 101. Each of the cameras 104 (104p1 to 104p5) is arranged along a direction toward thefront edge portions 36e (36e1 and 36e5) of the doctor blade 36 (the direction of arrow F inFig. 11 ), and is able to measure each of the positions of thefront edge portions 36e (36e1 and 36e5) of thedoctor blade 36. Furthermore, while, in the first exemplary embodiment, an example in which the measurement of the positions of thefront edge portions 36e (36e1 to 36e5) of thedoctor blade 36 is performed by the cameras 104 (104p1 to 104p5) is hereinafter described, a modification example in which the measurement is performed by non-contact sensors can be employed. - Here, the method of measuring (a calculation method for) the magnitude of the SB gap G is described. The measurement of the magnitude of the SB gap G is performed in a state in which the developing
sleeve 70 is supported by thesleeve supporting portions 42 of thedevelopment frame member 30, thedoctor blade 36 is attached to theblade attaching portion 41 of thedevelopment frame member 30, and thecover frame member 40 is fixed to thedevelopment frame member 30. Moreover, during measurement of the magnitude of the SB gap G, a light source (for example, a light-emitting diode (LED) or a light guide) is inserted into thedevelopment chamber 31 over the longitudinal direction of thedevelopment chamber 31. The light source inserted into thedevelopment chamber 31 radiates light from the inside of thedevelopment chamber 31 toward the SB gap G. Then, the cameras 104 (104p1 to 104p5) capture rays of light exiting from the SB gap G to the outside of thedevelopment frame member 30. At this time, the cameras 104 (104p1 to 104p5) readpositions 70a (70a1 to 70a5) at which the developingsleeve 70 is closest to thedoctor blade 36 on the surface of the developingsleeve 70, and also read thefront edge portions 36e (36e1 and 36e5) of thedoctor blade 36. Next, theapparatus 100 converts pixel values into distances based on image data read and generated by the cameras 104 (104p1 to 104p5), and calculates the magnitude of the SB gap G based on the distances. In a case where the calculated magnitude of the SB gap G is not within a predetermined range, theapparatus 100 makes adjustment to the SB gap G. - Here, details of the method of adjusting the SB gap G are described with reference to the schematic diagram of
Fig. 12 . Theapparatus 100 moves the fingers 101 (101p1 to 101p5) along the direction of arrow K inFig. 12 while grasping the grab portions 37 (37P1 to 37p5) of thedoctor blade 36 with thefingers 101. Furthermore, the direction of arrow K inFig. 12 is a direction in which the relative position of thedoctor blade 36 with respect to the developingsleeve 70 supported by thesleeve supporting portions 42 of thedevelopment frame member 30 is adjusted (in other words, a direction to define the SB gap G). Moreover, the direction of arrow K inFig. 12 represents a direction in which thedoctor blade 36 comes close to or moves away from the developingsleeve 70 supported by thesleeve supporting portions 42 of thedevelopment frame member 30. With this, the relative position of thefront edge portions 36e (36e1 and 36e5) of thedoctor blade 36 with respect to thepositions 70a (70a1 to 70a5) at which the developingsleeve 70 is closest to thedoctor blade 36 on the surface of the developingsleeve 70 is adjusted. - For example, suppose that the SB gap G calculated at an initial position in which the
doctor blade 36 has been caused to land on theblade attaching surface 41s of thedevelopment frame member 30 is 350 µm. On the other hand, suppose that the adjustment range of the SB gap G is 300 µm ± 30 µm and the allowable tolerance of the SB gap G is up to 60 µm. In this case, at the initial position in which thedoctor blade 36 has been caused to land on theblade attaching surface 41s of thedevelopment frame member 30, the calculated SB gap G is 50 µm larger than thenominal value 300 µm of the SB gap G. Therefore, thefingers 101 translate thedoctor blade 36 along the direction of arrow K illustrated inFig. 12 and in a direction to bring thedoctor blade 36 close to the surface of the developingsleeve 70 by 50 µm while grasping thegrab portions 37 of thedoctor blade 36. - Then, the cameras 104 read the
positions 70a (70a1 to 70a5) at which the developingsleeve 70 is closest to thedoctor blade 36 translated by thefingers 101 and thefront edge portions 36e (36e1 and 36e5) of thedoctor blade 36 translated by thefingers 101. Next, theapparatus 100 recalculates the SB gap G with respect to thedoctor blade 36 translated by thefingers 101. - When determining that the magnitude of the calculated SB gap G is within the range of adjustment values of the SB gap G (300 µm ± 30 µm), the
apparatus 100 ends adjustment of the SB gap G. On the other hand, when determining that the magnitude of the calculated SB gap G is not within the range of adjustment values of the SB gap G (300 µm ± 30 µm), theapparatus 100 repeats the above-described adjustment of the SB gap G until the magnitude of the calculated SB gap G falls within the adjustment range of the SB gap G (300 µm ± 30 µm). With the straightness of the coatedamount regulating surface 36r corrected to 50 µm or less in this way, thedoctor blade 36 is fixed to theblade attaching portion 41 of thedevelopment frame member 30, so that the magnitude of the SB gap G can be set to within the adjustment range of the SB gap G. - Here, a desirable configuration example for making adjustment of the SB gap G with a high degree of accuracy is described with reference to the schematic diagrams of
Figs. 13A and 13B andFig. 14 . In this configuration example, not only the straightness of the coatedamount regulating surface 36r of thedoctor blade 36 but also the straightness of the surface of the developingsleeve 70 is taken into consideration, so that the adjustment of the SB gap G is performed with a higher degree of accuracy. - Since a sleeve tube constituting the outer shell of the developing
sleeve 70 is made of metal, performing secondary cutting work on the sleeve tube enables the straightness of the surface of the developingsleeve 70 to have a high degree of accuracy such as ±15 µm or less. However, when the developingsleeve 70 is rotating during actual use, the straightness of ±15 µm of the surface of the developingsleeve 70 is seen as if the outer diameter of the developingsleeve 70 is apparently varying by ±15 µm. To minimize an influence on the SB gap G caused by the accuracy of the straightness of the coatedamount regulating surface 36r of thedoctor blade 36 during the rotation state of the developingsleeve 70, it is effective to measure the SB gap G while rotating the developingsleeve 70. -
Figs. 13A and 13B illustrate the positions of thefront edge portion 36e of thedoctor blade 36 in a state in which the developingsleeve 70 is stopped.Fig. 13A illustrates a state in which the SB gap G has been adjusted in a state in which the developingsleeve 70 is stopped at a position far from thedoctor blade 36. On the other hand,Fig. 13B illustrates a state in which the SB gap G has been adjusted in a state in which the developingsleeve 70 is stopped at a position close to thedoctor blade 36. Moreover,Fig. 14 illustrates the position of thefront edge portion 36e of thedoctor blade 36 in a state in which the developingsleeve 70 is rotating. - As illustrated in
Figs. 13A and 13B , while the magnitude of the SB gap G is the same between the states illustrated inFigs. 13A and 13B , the position of thefront edge portion 36e of thedoctor blade 36 differs between the states illustrated inFigs. 13A and 13B . Moreover, a difference occurs between the phase of the developingsleeve 70 in the state in which the developingsleeve 70 is stopped at a position far from thedoctor blade 36 and the phase of the developingsleeve 70 in the state in which the developingsleeve 70 is stopped at a position close to thedoctor blade 36. As a result, even if the SB gap G is adjusted with the same adjustment value of the SB gap G with use of the developingsleeve 70 of the same accuracy and thedoctor blade 36 of the same accuracy, thedoctor blade 36 would be fixed to theblade attaching portion 41 of thedevelopment frame member 30 in a state in which the position of thefront edge portion 36e differs. This would result in allowing manufacturing unevenness during manufacture of thedevelopment device 3. Therefore, adjusting the SB gap G while rotating the developingsleeve 70 is employed to reduce manufacturing unevenness. - When the developing
sleeve 70 is rotated, a fluctuation which is moving in and out of the outer diameter line of the developing sleeve 70 (hereinafter referred to as a "fluctuation of the outer diameter of the developingsleeve 70") occurs due to the straightness of the surface of the developingsleeve 70. As illustrated inFig. 14 , the outer diameter line of the developingsleeve 70 is seen as if the outer diameter line is moving in and out between an outer diameter line 73L1 of the developingsleeve 70 and an outer diameter line 73L2 of the developingsleeve 70 around a center line 73L0 of the fluctuation of the outer diameter of the developingsleeve 70. Therefore, measuring the fluctuation of the outer diameter of the developingsleeve 70 enables detecting the center of the fluctuation of the outer diameter of the developingsleeve 70. Thus, the method of detecting the center line 73L0 of the fluctuation of the outer diameter of the developingsleeve 70 and measuring the magnitude of the SB gap G based on the center line 73L0 of the fluctuation of the outer diameter of the developingsleeve 70 can be employed. This enables preventing or reducing unevenness of the position of thefront edge portion 36e of thedoctor blade 36, which is caused by a difference between the phase of the developingsleeve 70 in the state in which the developingsleeve 70 is stopped at a position far from thedoctor blade 36 and the phase of the developingsleeve 70 in the state in which the developingsleeve 70 is stopped at a position close to thedoctor blade 36. - Thus, the method of using the developing
sleeve 70 of the same accuracy and thedoctor blade 36 of the same accuracy and using the same adjustment value of the SB gap G while rotating the developingsleeve 70 enables reproducing the position of thefront edge portion 36e of thedoctor blade 36 at the same position. This enables reducing manufacturing unevenness. - While, as mentioned above, the straightness of the surface of the developing
sleeve 70 is ±15 µm or less, to perform adjustment of the SB gap G with a higher degree of accuracy, it is necessary to take not only the straightness of the coatedamount regulating surface 36r of thedoctor blade 36 but also the straightness of the surface of the developingsleeve 70 into account. Therefore, in the positioning step, theapparatus 100 performs the following operation in a state in which thefingers 101 cause thedoctor blade 36 to land on theblade attaching surface 41s while translating thedoctor blade 36 in a direction to bring thedoctor blade 36 close to the surface of the developingsleeve 70. - Before causing the
doctor blade 36 to land on theblade attaching surface 41s, theapparatus 100 imparts a straightness correction force for correcting the straightness of the coatedamount regulating surface 36r to thedoctor blade 36 via thegrab portions 37 of thedoctor blade 36. More specifically, before causing thedoctor blade 36 to land on theblade attaching surface 41s, theapparatus 100 previously corrects the straightness of the coatedamount regulating surface 36r to 50 µm or less. Then, theapparatus 100 causes thedoctor blade 36 with the straightness of the coatedamount regulating surface 36r corrected to 50 µm or less to land on theblade attaching surface 41s. - Next, the
apparatus 100 imparts, to thedoctor blade 36 via thegrab portions 37 of thedoctor blade 36, an adjustment force for adjusting the relative position of the coatedamount regulating surface 36r of thedoctor blade 36 with respect to the developingsleeve 70 so as to cause the SB gap G to fall within a predetermined range (in other words, an adjustment range of the SB gap G) in a state that thedoctor blade 36 is fixed to theblade attaching portion 41. More specifically, thefingers 101 warp at least a part of the area corresponding to the maximum image region of thedoctor blade 36 in such a manner that the SB gap G measured by the cameras 104 falls within the adjustment range of the SB gap G in a state in which thedoctor blade 36 has landed on theblade attaching surface 41s. At this time, at least a part of the area corresponding to the maximum image region of thedoctor blade 36 enters a state of being warped in a direction in which thedoctor blade 36 attached to theblade attaching portion 41 comes close to or moves away from the developingsleeve 70 supported by thesleeve supporting portions 42. - With this, the adjustment of the SB gap G with not only the straightness of the coated
amount regulating surface 36r of thedoctor blade 36 but also the straightness of the surface of the developingsleeve 70 taken into account can be performed with a higher degree of accuracy. Then, the relative position of the coatedamount regulating surface 36r of thedoctor blade 36 with respect to the developingsleeve 70 can also be performed in such a manner that the tolerance of the SB gap G becomes 60 µm or less over the longitudinal direction of the developingsleeve 70. In that case, after the relative position of the coatedamount regulating surface 36r with respect to the developingsleeve 70 is adjusted in such a manner that the tolerance of the SB gap G becomes 60 µm or less over the longitudinal direction of the developingsleeve 70, thedoctor blade 36 is fixed to theblade attaching portion 41 according to a fixation step described below. - Furthermore, in a case where the straightness of the surface of the developing
sleeve 70 has a higher accuracy (for example, ±5 µm or less), the adjustment of the SB gap G only needs to be performed in consideration of the straightness of the coatedamount regulating surface 36r, but does not necessarily need to be performed further in consideration of the straightness of the surface of the developingsleeve 70. Similarly, in a case where the latitude of the SB gap G is large, the adjustment of the SB gap G is performed in consideration of the straightness of the coatedamount regulating surface 36r of thedoctor blade 36, but does not necessarily need to be performed further in consideration of the straightness of the surface of the developingsleeve 70. - Next, details of the fixation step are described with reference to the schematic diagram of
Fig. 12 . In the first exemplary embodiment, as illustrated inFig. 12 , the fixation step is performed in a state in which thedoctor blade 36 kept in a warp state in the warping step has landed at a predetermined position of theblade attaching portion 41 of thedevelopment frame member 30 determined in the positioning step. - In the first exemplary embodiment, before causing the
doctor blade 36 to land on theblade attaching surface 41s of thedevelopment frame member 30, theapparatus 100 applies an adhesive A to theblade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region. Then, theapparatus 100 bonds (fixes) thedoctor blade 36 kept in a warp state in the warping step to theblade attaching portion 41 over the approximate entirety of the area corresponding to the maximum image region. At this time, thedoctor blade 36 is bonded (fixed) to theblade attaching portion 41 in a state in which the straightness of the coatedamount regulating surface 36r has been corrected to 50 µm or less. - Thus, in the first exemplary embodiment, the area warped to correct the straightness of the coated
amount regulating surface 36r, of the area corresponding to the maximum image region of thedoctor blade 36, is fixed to theblade attaching portion 41. This enables preventing or reducing the area warped to correct the straightness of the coatedamount regulating surface 36r, of the area corresponding to the maximum image region of thedoctor blade 36, from returning from the state of being warped to the original state obtained before being warped. - On the other hand, depending on the shape of the
blade attaching portion 41, there may exist an area in which it is difficult for theapparatus 100 to apply the adhesive A to theblade attaching surface 41s. In that case, as long as the area which has received a force for warping at least a part of the area corresponding to the maximum image region of thedoctor blade 36 is fixed to theblade attaching portion 41 with the adhesive A, the adhesive A is assumed not to be required to be applied to a part of theblade attaching surface 41s. - Therefore, the adhesive A being applied to the
blade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region means satisfying the following condition. The condition is that the adhesive A is applied to an area which includes an area warped to correct the straightness of the coatedamount regulating surface 36r of the area corresponding to the maximum image region of thedoctor blade 36 and which is 95% or more of the area corresponding to the maximum image region in the longitudinal direction of theblade attaching surface 41s. - With regard to selection of the adhesive A, the adhesive A is required to have such an adhesive strength that the
doctor blade 36 is prevented from coming unglued from theblade attaching surface 41s of thedevelopment frame member 30 in the process of an image forming operation (development operation). The load which is imparted to thedoctor blade 36 in the process of an image forming operation (development operation) is about 2 kilogram-force (kgf) at the time of drop test, and, if thedoctor blade 36 receiving such a magnitude of load does not come unglued from theblade attaching surface 41s of thedevelopment frame member 30, there is no problem. Therefore, it has been known that a sufficient adhesive strength can be ensured even with a general adhesive A, and, from a viewpoint of ensuring mass productivity, the shorter the hardening time of the adhesive A the better. - Next, the film thickness of the adhesive A which is applied to the
blade attaching surface 41s of thedevelopment frame member 30 is described. To bond thedoctor blade 36 and theblade attaching surface 41s of thedevelopment frame member 30 using the adhesive A, the adhesive A is arranged to intervene between thedoctor blade 36 and theblade attaching surface 41s of thedevelopment frame member 30. In order to prevent the adhesive A intervening between thedoctor blade 36 and theblade attaching surface 41s of thedevelopment frame member 30 from affecting the magnitude of the SB gap G, it is necessary to take the film thickness of the adhesive A which is applied to theblade attaching surface 41s into account. - The relationship between the film thickness of thee adhesive A and the magnitude of a breaking load of a portion bonded with the adhesive A is such a relationship that the larger the amount of the adhesive A, the larger the adhesive strength caused by the adhesive A becomes. As mentioned above, the load which is imparted to the
doctor blade 36 in the process of an image forming operation (development operation) is about 2 kgf, and, in the first exemplary embodiment, in view of tolerances, the strength required as the adhesive strength of the adhesive A is set to 10 kgf or more. Therefore, to ensure 10 kgf or more as the adhesive strength of the adhesive A, the film thickness of the adhesive A which is applied to theblade attaching surface 41s of thedevelopment frame member 30 only needs to be set to 20 µm or more. - Next, the relationship between the thickness with which to apply the adhesive A and the magnitude of dimensional variability in the thickness direction of the adhesive A is described. Generally, the larger the film thickness of the adhesive A, the more the dimensional variability in the thickness direction of the adhesive A caused by contraction of the adhesive A at the time of hardening of the adhesive A occurs. On the other hand, the magnitude of dimensional variability in the thickness direction of the adhesive A when the film thickness of the adhesive A is 150 µm is only about 8 µm larger than the magnitude of dimensional variability in the thickness direction of the adhesive A when the film thickness of the adhesive A is 30 µm. Such a difference of about 8 µm in the magnitude of dimensional variability in the thickness direction of the adhesive A is at a negligible level as the influence of the dimensional variability in a direction perpendicular to the thickness direction of the adhesive A (in other words, in a direction to define the SB gap G). Accordingly, the upper limit of the film thickness of the adhesive A which is applied to the
blade attaching surface 41s of thedevelopment frame member 30 is not determined based on the influence of contraction of the adhesive A but can be determined based on individual production requirements, such as the hardening time or cost of the adhesive A. - Furthermore, while, in the first exemplary embodiment, an example in which the adhesive A is applied to the
blade attaching portion 41 side has been described, a modification example in which the adhesive A is applied to thedoctor blade 36 side or a modification example in which the adhesive A is applied to both theblade attaching portion 41 side and thedoctor blade 36 side can be employed. Moreover, if the timing at which to apply the adhesive A to theblade attaching portion 41 side is prior to starting of the positioning step (more desirably, parallel with the warping step), the total time required for a series of steps of the fixation method for thedoctor blade 36 can be shortened. In other words, this example means a series of steps of applying the adhesive A to theblade attaching portion 41 of thedevelopment frame member 30 while correcting the straightness of the coatedamount regulating surface 36r. Therefore, in the first exemplary embodiment, the following description proceeds on the assumption that the step of applying the adhesive A to theblade attaching portion 41 side of thedevelopment frame member 30 is performed prior to starting of the positioning step. - In a case where the
doctor blade 36 is fixed with the adhesive A, if, in the positioning step, the adhesive A would harden halfway through the adjustment of the SB gap G with respect to thedoctor blade 36 caused to land on theblade attaching surface 41s, after that, the adjustment of the SB gap G becomes unable to be performed. Therefore, the adjustment of the SB gap G is required to be completed before the adhesive A hardens. The time in which the adhesive A hardens is determined based on the material of the adhesive A or the amount of application of the adhesive A. Therefore, the time in which the adhesive A hardens can be predicted to some extent. Thus, the number of times the adjustment of the SB gap G can be repeatedly performed before the adhesive A hardens is previously determined based on the time required for the adjustment of the SB gap G to be performed once. Therefore, as long as the range of the determined number of times is not exceeded, since the adhesive A has not yet hardened, the adjustment of the SB gap G can be repeatedly performed. - Furthermore, in the case of prioritizing repeatedly performing the adjustment of the SB gap G over shortening the total time required for a series of steps of the fixation method for the
doctor blade 36, a modification example in which the adhesive A is applied to theblade attaching portion 41 side after the positioning step is completed can be employed. In the modification example, in the positioning step, theapparatus 100 stores, in a memory included in theapparatus 100, information about a position at which to fix thedoctor blade 36 to theblade attaching surface 41s of thedevelopment frame member 30, which has been determined during the adjustment of the SB gap G. Then, after the positioning step is completed, theapparatus 100 performs a step of applying the adhesive A to theblade attaching portion 41 side of thedevelopment frame member 30. Then, after the adhesive A is applied to theblade attaching portion 41 side, theapparatus 100 causes thedoctor blade 36 kept in a warped state in the warping step to land on theblade attaching surface 41s of thedevelopment frame member 30 based on the information about the fixation position for thedoctor blade 36 stored in the memory. Then, after thedoctor blade 36 kept in a warped state lands on theblade attaching surface 41s, theapparatus 100 can start the above-described fixation step. - After the adjustment of the SB gap G is completed, to bring a space between the
doctor blade 36 and theblade attaching portion 41 of thedevelopment frame member 30 into a state of having an intended adhesive strength, it is necessary to keep thedoctor blade 36 in close contact with theblade attaching portion 41 until the adhesive A hardens. To bond thedoctor blade 36 to theblade attaching portion 41 with a sufficient adhesive strength, the degree of close contact between thedoctor blade 36 and theblade attaching portion 41 is important. This is because, in a case where a gap between thedoctor blade 36 and theblade attaching portion 41 is large, even if the adhesive A intervenes in the gap, the adhesive strength becomes weak. - Therefore, to bring the
doctor blade 36 into close contact with theblade attaching portion 41, it is necessary to impart a given load. Specifically, while keeping thedoctor blade 36 landing on theblade attaching surface 41s of thedevelopment frame member 30, theapparatus 100 drops a weight having a predetermined weight on thedoctor blade 36, thus imparting a load for bringing thedoctor blade 36 into close contact with theblade attaching portion 41. To obtain a sufficient adhesion strength, in a state in which such a load is imparted to keep thedoctor blade 36 in close contact with theblade attaching portion 41, thefingers 101 have to continue holding thedoctor blade 36 until the adhesive A sufficiently hardens. For example, in a case where the hardening time of the adhesive A is 15 seconds, the load for bringing thedoctor blade 36 into close contact with theblade attaching portion 41 can be configured to continue being imparted for 20 seconds in view of tolerances. - Then, after the adhesion of the
doctor blade 36 to theblade attaching portion 41 is completed, theapparatus 100 raises the weight, thus removing the load from thedoctor blade 36. Then, theapparatus 100 causes the fingers 101 (101p1 to 101p5) to operate, and, after moving the fingers 101 (101p1 to 101p5) away from thedoctor blade 36, moves the fingers 101 (101p1 to 101p5) to a preparatory position for a next operation. - The above are the details of steps of the fixation method for the
doctor blade 36. In a series of steps of the fixation method described above, an example in which, before causing thedoctor blade 36 the accuracy of the coatedamount regulating surface 36r of which is about 300 µm to 500 µm to land on theblade attaching surface 41s, theapparatus 100 previously corrects the straightness of the coatedamount regulating surface 36r to 50 µm or less has been described. As a result, even if thedoctor blade 36 made of resin, the accuracy of the coatedamount regulating surface 36r of which is low, is used, the SB gap G can be configured to fall within the adjustment range of the SB gap G in a state that thedoctor blade 36 is fixed to theblade attaching portion 41. In this example, the function of performing the warping step and the function of performing the positioning step are performed by respectiveseparate apparatuses 100. More specifically, the doctor blade 36 (single body) is placed on theplacement board 103 of theapparatus 100 for performing the warping step, which is an apparatus different from theapparatus 100 for performing the positioning step. Then, with the doctor blade 36 (single body) placed on theplacement board 103, theapparatus 100 for performing the warping step imparts, to thedoctor blade 36, a force for warping at least a part of the area corresponding to the maximum image region of thedoctor blade 36. - On the other hand, a modification example in which the function of performing the warping step and the function of performing the positioning step are included in the
single apparatus 100 is conceivable. In that modification example, thesingle apparatus 100 does not previously correct the straightness of the coatedamount regulating surface 36r to 50 µm or less before causing thedoctor blade 36 the accuracy of the coatedamount regulating surface 36r of which is about 300 µm to 500 µm to land on theblade attaching surface 41s. Instead, after causing thedoctor blade 36 to land on theblade attaching surface 41s, until the adhesive A hardens, thesingle apparatus 100 warps at least a part of the area corresponding to the maximum image region of thedoctor blade 36 in such a manner that the SB gap G falls within the adjustment range of the SB gap G. In other words, this modification example means a series of steps of, while fixing thedoctor blade 36 to theblade attaching surface 41s, warping at least a part of the area corresponding to the maximum image region of thedoctor blade 36 in such a manner that the SB gap G falls within a predetermined range (in other words, the adjustment range of the SB gap G). As a result, even if thedoctor blade 36 made of resin, the accuracy of the coatedamount regulating surface 36r of which is low, is used, the SB gap G can be configured to fall within the adjustment range of the SB gap G in a state that thedoctor blade 36 is fixed to theblade attaching portion 41. - However, as mentioned above, in a case where the doctor blade made of resin compatible with A3 size is manufactured with the accuracy of a general resin product, the straightness of the coated amount regulating surface is about 300 µm to 500 µm. From this, it is desirable that the
apparatus 100 previously correct the straightness of the coatedamount regulating surface 36r to 50 µm or less before causing thedoctor blade 36 to land on theblade attaching surface 41s. This is because, since the adjustment of the SB gap G is performed with the straightness of the coatedamount regulating surface 36r corrected to 50 µm or less, the required adjustment time becomes shorter as compared with the case of performing the adjustment of the SB gap G with the straightness of the coatedamount regulating surface 36r being about 300 µm to 500 µm. In other words, since the time required for a step performed with thedoctor blade 36 landing on theblade attaching surface 41s (the adjustment time for the SB gap G) becomes shorter, the time required for the adhesive A applied to theblade attaching surface 41s to harden can be set shorter. Moreover, the case where the function for performing the warping step and the function for performing the positioning step are included in the respectiveseparate apparatuses 100 enables generally shortening the takt time as compared with the case where both functions are included in thesingle apparatus 100, and is, therefore, advantageous in terms of mass productivity. - Next, a deformation of the
doctor blade 36 caused by the developer pressure occurring from the flow of a developer being imparted to thedoctor blade 36 in the process of an image forming operation (development operation) is described with reference to the sectional view ofFig. 15. Fig. 15 is a sectional view of thedevelopment device 3 in a cross-section perpendicular to the rotational axis of the developing sleeve 70 (the cross-section H inFig. 2 ). Moreover,Fig. 15 illustrates a configuration near thedoctor blade 36 fixed to theblade attaching portion 41 of thedevelopment frame member 30 with the adhesive A. - As illustrated in
Fig. 15 , a line connecting a position of thedoctor blade 36 closest to the developingsleeve 70 in the coatedamount regulating surface 36r to the rotational center of the developingsleeve 70 is set as the X-axis. At this time, the length in the X-axis direction of thedoctor blade 36 is large, and the rigidity thereof in a cross-section in the X-axis direction is also large. Moreover, as illustrated inFig. 15 , the ratio of the cross-sectional area T1 of thedoctor blade 36 to the cross-sectional area T2 of thewall portion 30a of thedevelopment frame member 30 located near thedeveloper guide portion 35 is small. As mentioned above, in the first exemplary embodiment, the rigidity of the development frame member 30 (single body) is set 10 times or larger than the rigidity of the doctor blade 36 (single body). Accordingly, in a state in which thedoctor blade 36 is fixed to theblade attaching portion 41 of thedevelopment frame member 30, the rigidity of thedevelopment frame member 30 becomes more dominant than the rigidity of thedoctor blade 36. As a result, in the process of an image forming operation (development operation), the amount of displacement (the maximum amount of warp) of the coatedamount regulating surface 36r of thedoctor blade 36 obtained when thedoctor blade 36 has received the developer pressure becomes substantially equivalent to the amount of displacement (the maximum amount of warp) of thedevelopment frame member 30. - In the process of an image forming operation (development operation), a developer scooped up by the
first conveyance screw 33 passes through thedeveloper guide portion 35 and is then conveyed to the surface of the developingsleeve 70. After that, even when the layer thickness of the developer is defined by thedoctor blade 36 with the magnitude of the SB gap G, thedoctor blade 36 is receiving the developer pressure from various directions. As illustrated inFig. 15 , when a direction perpendicular to the X-axis direction (a direction to define the SB gap G) is set as the Y-axis, the developer pressure in the Y-axis direction is perpendicular to theblade attaching surface 41s of thedevelopment frame member 30. In other words, the developer pressure in the Y-axis direction becomes a force in a direction to unglue thedoctor blade 36 from theblade attaching surface 41s. Therefore, the bonding force caused by the adhesive A is required to be sufficiently large with respect to the developer pressure in the Y-axis direction. Thus, in the first exemplary embodiment, the adhesion area or application thickness of the adhesive A with respect to theblade attaching surface 41s is optimized in consideration of the force acting in a direction to unglue thedoctor blade 36 from theblade attaching surface 41s or the adhesion force of the adhesive A. Moreover, in the first exemplary embodiment, since the cross-sectional area T2 of thewall portion 30a of thedevelopment frame member 30 is set sufficiently large with respect to the developer pressure in the Y-axis direction which thedeveloper guide portion 35 receives, thedoctor blade 36 can be prevented or reduced from being deformed by the developer pressure in the process of an image forming operation (development operation). - Next, a deformation of the
doctor blade 36 caused by the temperature being changed by heat generated in the process of an image forming operation (development operation) is described with reference to the perspective view ofFig. 16 . The heat generated in the process of a development operation includes, for example, heat generated during rotation of the rotation shaft of the developingsleeve 70 with respect to thebearings 71, heat generated during rotation of therotation shaft 33a of thefirst conveyance screw 33 with respect to the bearing members, and heat generated by the developer passing through the SB gap G. The temperature around thedevelopment device 3 changes due to these types of heat generated in the process of an image forming operation (development operation), so that the temperatures of thedoctor blade 36, thedevelopment frame member 30, and thecover frame member 40 also change. - On the other hand, in a case where a linear expansion coefficient α1 of a resin that makes up the
doctor blade 36 and a linear expansion coefficient α2 of a resin that makes up thedevelopment frame member 30 differ from each other, a difference of these linear expansion coefficients may vary the amount of deformation caused by a temperature change. As mentioned above, the first exemplary embodiment employs a method of fixing thedoctor blade 36 to theblade attaching portion 41 of thedevelopment frame member 30 with the adhesive A over the approximate entirety of the area corresponding to the maximum image region. Moreover, in a case where there is a large difference between the linear expansion coefficient α2 of a resin that makes up thedevelopment frame member 30 and the linear expansion coefficient α1 of a resin that makes up thedoctor blade 36, the following problem arises when a temperature change has occurred. Specifically, when a temperature change has occurred, the amount of deformation (amount of expansion and contraction) of thedoctor blade 36 caused by the temperature change and the amount of deformation (amount of expansion and contraction) of thedevelopment frame member 30 caused by the temperature change may become different from each other. - For example, suppose that the
doctor blade 36 is fixed to theblade attaching surface 41s at least at a first area, a second area, and a third area in the area corresponding to the maximum image region of the doctor blade 36 (for example, at least at three locations including both end portions and a central portion of the area corresponding to the maximum image region of the doctor blade 36). In this case, since the amount of thermal expansion differs between both end portions and a central portion of thedoctor blade 36, the warp of thedoctor blade 36 may become large, so that thedoctor blade 36 may be greatly warped. As a result, even if the SB gap G is adjusted with a high degree of accuracy when the position at which to attach thedoctor blade 36 to theblade attaching surface 41s of thedevelopment frame member 30 is determined, the magnitude of the SB gap G may be varied due to a temperature change in the process of an image forming operation (development operation). - Since, in the first exemplary embodiment, the
doctor blade 36 is fixed to theblade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region of thedoctor blade 36, it is necessary to prevent or reduce a variation of the magnitude of the SB gap G caused by a temperature change in the process of an image forming operation (development operation). - As illustrated in
Fig. 16 , suppose that the amount of extension of thedoctor blade 36 caused by a temperature change is H [µm] and the amount of extension of theblade attaching surface 41s of theblade attaching portion 41 of thedevelopment frame member 30 caused by a temperature change is I [µm]. Moreover, suppose that the linear expansion coefficient α1 of a resin that makes up thedoctor blade 36 and the linear expansion coefficient α2 of a resin that makes up thedevelopment frame member 30 differ from each other. In this case, a difference of these linear expansion coefficients causes a difference in the amount of deformation caused by a temperature change between thedevelopment frame member 30 and thedoctor blade 36, so that, to make up for the difference between the amounts of extension H [µm] and I [µm], thedoctor blade 36 would deform along the direction of arrow J inFig. 16 . The deformation of thedoctor blade 36 along the direction of arrow J inFig. 16 is hereinafter referred to as a "deformation in a warp direction of thedoctor blade 36". Then, the deformation in a warp direction of thedoctor blade 36 would lead to a variation of the magnitude of the SB gap G. Each of the linear expansion coefficient α2 of a resin that makes up thesleeve supporting portions 42 and theblade attaching portion 41 of the development frame member 30 (single body) and the linear expansion coefficient α1 of a resin that makes up the doctor blade 36 (single body) is related to preventing or reducing a variation of the magnitude of the SB gap G caused by heat. - Here, the difference of the linear expansion coefficient α2 of a resin that makes up the
development frame member 30, which includes thesleeve supporting portions 42 and theblade attaching portion 41, from the linear expansion coefficient α1 of a resin that makes up thedoctor blade 36 is hereinafter referred to as a "linear expansion coefficient difference α2-α1". A change of the maximum amount of warp of thedoctor blade 36 caused by the linear expansion coefficient difference α2-α1 is described with use of Table 1. In a state in which thedoctor blade 36 was fixed to theblade attaching portion 41 of thedevelopment frame member 30 over the approximate entirety of the area corresponding to the maximum image region, a measurement of the maximum amount of warp of thedoctor blade 36 obtained when a temperature changed from an ordinary temperature (23 °C) to a high temperature (40 °C) was made. - Suppose that the linear expansion coefficient of a resin that makes up the
development frame member 30, which includes thesleeve supporting portions 42 and theblade attaching portion 41, is α2 [m/°C] and the linear expansion coefficient of a resin that makes up thedoctor blade 36 is α1 [m/°C]. Then, a result obtained by measuring the maximum amount of warp of thedoctor blade 36 while varying parameters of the linear expansion coefficient difference α2-α1 is shown in Table 1. - As mentioned above, to prevent or reduce unevenness of the amount of a developer borne on the surface of the developing
sleeve 70 in the longitudinal direction of the developingsleeve 70, it is generally necessary to limit the amount of variation of the SB gap G caused by heat to ±20 µm or less. Thus, in Table 1, in a case where the absolute value of the maximum amount of warp of thedoctor blade 36 is 20 µm or less, the maximum amount of warp is denoted by "o", and, in a case where the absolute value of the maximum amount of warp of thedoctor blade 36 is greater than 20 µm, the maximum amount of warp is denoted by "×".Table 1 Linear expansion coefficient difference α2-α1 [× 10-5 m/°C] Maximum amount of warp of doctor blade 0 ○ +0.20 ○ +0.40 ○ +0.50 ○ +0.54 ○ +0.55 ○ +0.56 × +0.57 × +0.60 × Linear expansion coefficient difference α2-α1 [× 10-5 m/°C] Maximum amount of warp of doctor blade 0 ○ -0.20 ○ -0.40 ○ -0.44 ○ -0.45 ○ -0.46 × -0.47 × -0.50 × -
- Therefore, the resin that makes up the
development frame member 30 and the resin that makes up thedoctor blade 36 can be selected in such a manner that the linear expansion coefficient difference α2-α1 becomes -0.45 × 10-5 [m/°C] or more and 0.55 × 10-5 [m/°C] or less. Selecting resins in such a manner that the linear expansion coefficient difference α2-α1 satisfies the relational expression (1) as the resin that makes up thedevelopment frame member 30 and the resin that makes up thedoctor blade 36 enables limiting the amount of variation of the SB gap G caused by heat to ±20 µm or less. It is more desirable that the linear expansion coefficient difference α2-α1 be set to zero. To set the linear expansion coefficient difference α2-α1 to zero, the same resin can be selected as the resin that makes up thedevelopment frame member 30 and the resin that makes up thedoctor blade 36. - Moreover, since the
cover frame member 40 is fixed to thedevelopment frame member 30, if the amounts of deformation of thedevelopment frame member 30 and thecover frame member 40 caused by heat differ from each other, the deformation of thecover frame member 40 along the warp direction would lead to a variation of the magnitude of the SB gap G. As a result, even if the SB gap G is adjusted with a high degree of accuracy in the positioning step for thedoctor blade 36, the magnitude of the SB gap G may be varied due to a temperature change in the process of an image forming operation (development operation). - Each of the linear expansion coefficient α2 of a resin that makes up the
sleeve supporting portions 42 and theblade attaching portion 41 of the development frame member 30 (single body) and the linear expansion coefficient α3 of a resin that makes up the cover frame member 40 (single body) is related to preventing or reducing a variation of the magnitude of the SB gap G caused by a temperature change. As mentioned above, it is necessary to limit the amount of variation of the SB gap G caused by heat to ±20 µm or less. Suppose that the linear expansion coefficient of a resin that makes up thedevelopment frame member 30, which includes thesleeve supporting portions 42 and theblade attaching portion 41, is α2 [m/°C] and the linear expansion coefficient of a resin that makes up thecover frame member 40 is α3 [m/°C]. - Here, the difference of the linear expansion coefficient α3 of a resin that makes up the
cover frame member 40 from the linear expansion coefficient α2 of a resin that makes up thedevelopment frame member 30, which includes thesleeve supporting portions 42 and theblade attaching portion 41, is hereinafter referred to as a "linear expansion coefficient difference α3-α2". As with Table 1, it is necessary to satisfy the following relational expression (2) with regard to the linear expansion coefficient difference α3-α2. - Therefore, the resin that makes up the
development frame member 30 and the resin that makes up thecover frame member 40 can be selected in such a manner that the linear expansion coefficient difference α3-α2 becomes -0.45 × 10-5 [m/°C] or more and 0.55 × 10-5 [m/°C] or less. Selecting resins in such a manner that the linear expansion coefficient difference α3-α2 satisfies the relational expression (2) as the resin that makes up thedevelopment frame member 30 and the resin that makes up thecover frame member 40 enables limiting the amount of variation of the SB gap G caused by heat to ±20 µm or less. It is more desirable that the linear expansion coefficient difference α3-α2 be set to zero. To set the linear expansion coefficient difference α3-α2 to zero, the same resin can be selected as the resin that makes up thedevelopment frame member 30 and the resin that makes up thecover frame member 40. - Furthermore, when the adhesive A is applied to the
doctor blade 36 or thedevelopment frame member 30, the linear expansion coefficient of thedoctor blade 36 or thedevelopment frame member 30 with the adhesive A applied thereto would vary. However, the volume itself of the adhesive A applied to thedoctor blade 36 or thedevelopment frame member 30 is very small, so that an influence on a change in dimension in the thickness direction of the adhesive A caused by a temperature change is at an ignorable level. Therefore, the deformation of thedoctor blade 36 in a warp direction caused by the linear expansion coefficient difference α2-α1 varying when the adhesive A is applied to thedoctor blade 36 or thedevelopment frame member 30 is at an ignorable level. - Generally, many of resin products are inferior in abrasion resistance to metal products. Factors pertaining to abrasion resistance of the
doctor blade 36 include a developer pressure to be imparted to thedoctor blade 36. In selecting a resin that makes up thedoctor blade 36, it has been known that a resin with a larger surface hardness is more excellent in abrasion resistance. - Thus, in view of abrasion resistance, a resin having a surface hardness of 100 or more in the scale L of Rockwell hardness (JIS K7202-2) can be selected as the resin that makes up the
doctor blade 36. This enables preventing or reducing abrasion of thedoctor blade 36 in the process of an image forming operation (development operation). Thedoctor blade 36 made of such a resin has only an abrasion of 10 µm or less even in an endurance test using the equivalence of about 500,000 sheets of paper. While the larger the surface hardness of thedoctor blade 36, the more the abrasion resistance of thedoctor blade 36 is improved, the mass productivity of thedoctor blade 36 tends to decrease. This is because a resin with a large surface hardness generally contains much toughening agent such as glass fiber. When molding is performed with a mold with use of such a resin having a large surface hardness, the toughening agent contained in the resin may damage the mold. Therefore, in a case where more than a given amount of toughening agent is contained in a resin, the mass productivity of thedoctor blade 36 becomes unable to be maintained. Therefore, it has been known that selecting a resin having a surface hardness of 100 or less in the scale M of Rockwell hardness (JIS K7202-2) as the resin that makes up thedoctor blade 36 enables ensuring the mass productivity of thedoctor blade 36. - In the first exemplary embodiment, in view of both the abrasion resistance and mass productivity of the
doctor blade 36, thedoctor blade 36 is molded with use of a resin having a surface hardness of 100 or more in the scale L of Rockwell hardness and 100 or less in the scale M of Rockwell hardness. The resin having a surface hardness of 100 or more in the scale L of Rockwell hardness and 100 or less in the scale M of Rockwell hardness includes the following examples. For example, the resin includes a resin having a base material of polyphenylene ether (PPE) and polystyrene (PS) and containing a toughening agent in the range of 30% by weight or more and 35% by weight or less (hereinafter referred to as a "resin X"). Moreover, for example, the resin includes a resin having a base material of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) and containing a toughening agent in the range of 20% by weight or more and 30% by weight or less (hereinafter referred to as a "resin Y"). - Thus, suppose that, in view of both the abrasion resistance and mass productivity of the
doctor blade 36, the "resin X" or the "resin Y" is selected as the resin that makes up thedoctor blade 36. In this case, a resin that makes up thedevelopment frame member 30 can be selected in such a manner that the difference of the linear expansion coefficient α2 of thedevelopment frame member 30 from the linear expansion coefficient α1 of the doctor blade 36 (the linear expansion coefficient difference α2-α1) satisfies the above-mentioned relational expression (1). - In a case where the "resin X" is selected as the resin that makes up the
doctor blade 36, if the resin X" or the "resin Y" is selected as the resin that makes up thedevelopment frame member 30, the linear expansion coefficient difference α2-α1 satisfies the above-mentioned relational expression (1). Moreover, in a case where the "resin Y" is selected as the resin that makes up thedoctor blade 36, if the resin X" or the "resin Y" is selected as the resin that makes up thedevelopment frame member 30, the linear expansion coefficient difference α2-α1 satisfies the above-mentioned relational expression (1). - On the other hand, in a case where the "resin X" is selected as the resin that makes up the
development frame member 30, the resin X" or the "resin Y" can be selected as the resin that makes up thecover frame member 40. In this case, the difference of the linear expansion coefficient α2 of thedevelopment frame member 30 from the linear expansion coefficient α3 of the cover frame member 40 (the linear expansion coefficient difference α2-α3) satisfies the above-mentioned relational expression (2). Moreover, in a case where the "resin Y" is selected as the resin that makes up thedevelopment frame member 30, if the resin X" or the "resin Y" is selected as the resin that makes up thecover frame member 40, the linear expansion coefficient difference α2-α3 satisfies the above-mentioned relational expression (2) . - As described above, in the first exemplary embodiment, a
doctor blade 36 in which the accuracy of the straightness of the coatedamount regulating surface 36r is the accuracy of a general resin product is used. Then, in a state in which the straightness of the coatedamount regulating surface 36r has been corrected by warping a part of the area corresponding to the maximum image region of thedoctor blade 36, thedoctor blade 36 is configured to be fixed to theblade attaching surface 41s over the approximate entirety of the area corresponding to the maximum image region. With such a configuration, even if a doctor blade made of resin compatible with A3 size in which the accuracy of the straightness of the coatedamount regulating surface 36r is low is used, the SB gap G can be configured to fall within the range of about 300 µm ± 30 µm (in other words, the adjustment range of the SB gap G). - Moreover, in the first exemplary embodiment, the resin that makes up the
doctor blade 36 is selected in view of both the abrasion resistance and mass productivity of thedoctor blade 36. Then, the resin that makes up thedevelopment frame member 30 is selected in such a manner that the difference of the linear expansion coefficient α2 of thedevelopment frame member 30 from the linear expansion coefficient α1 of the doctor blade 36 (the linear expansion coefficient difference α2-α1) satisfies the above-mentioned relational expression (1). Moreover, the resin that makes up thecover frame member 40 is selected in such a manner that the difference of the linear expansion coefficient α2 of thedevelopment frame member 30 from the linear expansion coefficient α3 of the cover frame member 40 (the linear expansion coefficient difference α2-α3) satisfies the above-mentioned relational expression (2). As a result, a variation of the magnitude of the SB gap G caused by a temperature change in the process of an image forming operation (development operation) can be prevented or reduced. - Moreover, in the first exemplary embodiment, the
doctor blade 36 is configured to be fixed to theblade attaching portion 41 of thedevelopment frame member 30 over the approximate entirety of the area corresponding to the maximum image region. With this, the rigidity of thedoctor blade 36 in a state of being fixed to thedevelopment frame member 30 can be made larger as compared with the case of fixing only both end portions (two locations) of thedoctor blade 36 in the longitudinal direction of thedoctor blade 36 to theblade attaching portion 41. As a result, a variation of the magnitude of the SB gap G caused by the developer pressure being imparted to thedoctor blade 36 in the process of an image forming operation (development operation) can be prevented or reduced. - In the above-described first exemplary embodiment, an example in which the adhesive A is applied to the
blade attaching surface 41s of thedevelopment frame member 30 over the approximate entirety of the area corresponding to the maximum image region has been described. The adhesive A being applied to theblade attaching surface 41s of thedevelopment frame member 30 over the approximate entirety of the area corresponding to the maximum image region causes an area warped of the area corresponding to the maximum image region of thedoctor blade 36 to be fixed to theblade attaching surface 41s. With this, an area warped to correct the straightness of the coatedamount regulating surface 36r of the area corresponding to the maximum image region of thedoctor blade 36 is prevented or reduced from returning from the warped state to an original state obtained before being warped. - On the other hand, a second exemplary embodiment of the invention differs from the first exemplary embodiment in that the
apparatus 100 applies the adhesive A to theblade attaching surface 41s of thedevelopment frame member 30 not over the approximate entirety of the area corresponding to the maximum image region. In the second exemplary embodiment, theapparatus 100 stores, in the memory, information about an area warped to correct the straightness of the coatedamount regulating surface 36r of the area corresponding to the maximum image region of thedoctor blade 36. Next, theapparatus 100 determines a given area to which to apply the adhesive A of the area corresponding to the maximum image region of theblade attaching surface 41s of thedevelopment frame member 30 based on the information about an area warped of thedoctor blade 36 stored in the memory. Then, theapparatus 100 applies the adhesive A to the determined given area of theblade attaching surface 41s. Furthermore, the application width or film thickness of the adhesive A to be applied to theblade attaching surface 41s can be determined based on the adhesion strength of the adhesive A or the amount of application of the adhesive A in view of man-hour or cost. With this, the area warped of the area corresponding to the maximum image region of thedoctor blade 36 is fixed to theblade attaching surface 41s. - Moreover, to prevent or reduce a variation of the magnitude of the SB gap G caused by the developer pressure being imparted to the
doctor blade 36 in the process of an image forming operation (development operation), it is desired to make larger the rigidity of thedoctor blade 36 in a state of being fixed to thedevelopment frame member 30. Therefore, it is desirable that theapparatus 100 further apply the adhesive A to at least three locations including both end portions and an approximate central portion of the area corresponding to the maximum image region of theblade attaching surface 41s of thedevelopment frame member 30 in addition to the determined given area of theblade attaching surface 41s. Furthermore, the approximate central portion of the area corresponding to the maximum image region of theblade attaching surface 41s is assumed to cover an area obtained by translating the central portion of the area corresponding to the maximum image region of theblade attaching surface 41s toward one end side or toward the other end side by a length that is 10% or less of the length in the longitudinal direction of the area. - With this, not only the area warped of the area corresponding to the maximum image region of the
doctor blade 36 but also at least three locations including both end portions and an approximate central portion of the area corresponding to the maximum image region of thedoctor blade 36 are fixed to theblade attaching surface 41s. Therefore, since the rigidity of thedoctor blade 36 in a state of being fixed to thedevelopment frame member 30 can be made larger, a variation of the magnitude of the SB gap G caused by the developer pressure being imparted to thedoctor blade 36 in the process of an image forming operation (development operation) can be prevented or reduced. - Furthermore, the method of fixing at least three locations including both end portions and an approximate central portion of the area corresponding to the maximum image region of the
doctor blade 36 to theblade attaching surface 41s is not limited to a fixation method using the adhesive A, remaining within the scope of the claims, but can be an exemplary fixation method using screws.Fig. 17 is a perspective view illustrating a configuration of adevelopment device 300 in which three locations including both end portions and an approximate central portion of the area corresponding to the maximum image region of thedoctor blade 36 are fixed to theblade attaching surface 41s with screws 80.Fig. 18 is a sectional view of thedevelopment device 300 in a cross-section H inFig. 17 , and illustrates a configuration near thedoctor blade 36 fixed to theblade attaching portion 41 of thedevelopment frame member 30 with thescrews 80. InFig. 17 , members assigned with the respective same reference characters as those inFig. 2 have the respective same configurations. Moreover, inFig. 18 , members assigned with the respective same reference characters as those inFig. 15 have the respective same configurations. - In the example illustrated in
Fig. 17 , insert nuts are inserted at fixation positions of theblade attaching surface 41s of thedevelopment frame member 30. Then, thescrews 80 are fastened to the insert nuts, so that the fastening power for fixing thedoctor blade 36 to theblade attaching surface 41s is increased. As long as the fastening power can be maintained, instead of the insert nuts, self-tapping screws can be used for fastening in such a manner that thescrews 80 can tap their own holes as thescrews 80 are driven. - To fix the
doctor blade 36 to theblade attaching surface 41s with thescrews 80, after the adjustment of the SB gap G is completed in the above-mentioned positioning step, thedoctor blade 36 can be fixed to theblade attaching surface 41s with thescrews 80. Furthermore, thegrab portions 37 of thedoctor blade 36 are located at positions each obtained by shifting a length equivalent to a fixed width per location by thescrew 80 with respect to a screw fastening portion provided on thedoctor blade 36 for fastening by thescrew 80 to theblade attaching surface 41s. In the example illustrated inFig. 17 , the fixed width per location by thescrew 80 is equivalent to the width occupied by thescrew 80 for fastening, and is about 5 mm. - The invention is not limited to the above-described exemplary embodiments, but can be modified or altered in various manners (including an organic combination of some or all of the exemplary embodiments) based on the gist of the invention, which are not excluded from the scope of the claims.
- While, in the above-described exemplary embodiments, as illustrated in
Fig. 4 , an example in which thedeveloper guide portion 35 and thedevelopment frame member 30 are configured as an integrally formed member and thedeveloper guide portion 35 and thedoctor blade 36 are configured as separately formed members has been described, the exemplary embodiments are not limited to this example. As long as the rigidity of the doctor blade 36 (single body) allows thefingers 101 to warp thedoctor blade 36 and the flow of a developer or the developer pressure in the process of a development operation is within the range of design values, thedeveloper guide portion 35 and thedoctor blade 36 can be configured as an integrally formed member. - Furthermore, while, in the above-described exemplary embodiments, as illustrated in
Fig. 1 , theimage forming apparatus 60 having a configuration in which theintermediate transfer belt 61 is used as an image bearing member has been described as an example, the exemplary embodiments are not limited to this example. The invention can also be applied to an image forming apparatus having a configuration in which transfer is performed by sequentially bringing a recording medium into direct contact with thephotosensitive drums 1. In that case, eachphotosensitive drum 1 constitutes a rotatable image bearing member which bears a toner image. - Moreover, while, in the above-described exemplary embodiments, as illustrated in
Fig. 2 , thedevelopment device 3 having a configuration in which the developingsleeve 70 rotates counterclockwise and thedoctor blade 36 is located below the developingsleeve 70 has been described as an example, the exemplary embodiments are not limited to this example. The invention can also be applied to adevelopment device 3 having a configuration in which the developingsleeve 70 rotates clockwise and thedoctor blade 36 is located above the developingsleeve 70. - Besides, while, in the above-described exemplary embodiments, as illustrated in
Fig. 2 , thedevelopment device 3 having a configuration in which thedevelopment chamber 31 and theagitation chamber 32 are arranged horizontally side by side with respect to the horizontal direction has been described as an example, the exemplary embodiments are not limited to this example. The invention can also be applied to adevelopment device 3 having a configuration in which thedevelopment chamber 31 and theagitation chamber 32 are arranged vertically side by side with respect to the direction of gravitational force. - Additionally, while, in the above-described exemplary embodiments, the
development device 3 has been described as a single unit, even a configuration formed as a process cartridge, which is obtained by unitizing the image forming unit 600 (seeFig. 1 ) including thedevelopment device 3 and is configured to be detachably attached to theimage forming apparatus 60, can attain a similar advantageous effect. Moreover, the invention can be applied to anyimage forming apparatus 60 including such adevelopment device 3 or process cartridge regardless of monochrome image forming apparatuses and color image forming apparatuses. - 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, but, it is limited by the following claims.
Claims (10)
- A method of attaching a regulating blade (36) made of resin to an attaching portion (41) of a development frame member (30) made of resin, the attaching portion(41) being used to attach the regulating blade (36), the regulating blade (36) being (i) arranged in non-contact with a developer bearing member (70) that is arranged to carry a developer for developing an electrostatic latent image formed on an image bearing member (1), (ii) arranged to face the developer bearing member (70), and (iii) configured to regulate an amount of the developer to be carried on the developer bearing member (70),
characterized in that
the method of attaching the regulating blade (36) comprising:a warping step comprising imparting, to the regulating blade (36), a force for warping the regulating blade (36) in such a manner that a gap (G) between the developer bearing member(70) supported by the development frame member (30) and the regulating blade (36) attached to the attaching portion (41) is adjusted to within a predetermined range along a longitudinal direction of the developer bearing member (70); andan attaching step comprising attaching, with an adhesive (A), the regulating blade (36) to the attaching portion (41) in a state in which the regulating blade (36) is kept warped by the force imparted to the regulating blade (36) in the warping step and the gap (G) is within the predetermined range along the longitudinal direction of the developer bearing member (70). - The method of attaching the regulating blade (36) according to claim 1,
wherein the warping step imparts the force to the regulating blade (36) along a direction in which a relative position of the regulating blade (36) with respect to the developer bearing member (70) is adjusted. - The method of attaching the regulating blade (36) according to claim 1 or claim 2, wherein the gap (G) is adjusted such that the absolute value of a difference between a maximum value of the gap (G) and a median value of the gap (G) is less than or equal to 10%of the median value of the gap (G), and wherein the absolute value of a difference between a minimum value of the gap (G) and the median value of the gap (G) is less than or equal to 10% of the median value of the gap (G).
- The method of attaching the regulating blade (36) according to any one of claims 1 to 3, wherein the warping step imparts the force to the regulating blade (36) in a state that the regulating blade (36) is attached to the attaching portion (41).
- The method of attaching the regulating blade (36) according to any one of claims 1 to 4, further comprising an application step of applying the adhesive (A) to the attaching portion (41),
wherein the regulating blade (36) is attached to the attaching portion (41) applied with the adhesive (A) in the attaching step . - The method of attaching the regulating blade (36) according to claim 5, wherein the warping step imparts the force to the regulating blade (36) in a state that the regulating blade (36) is attached to the attaching portion (41) with the adhesive (A) applied thereto in the application step.
- A development device (3) comprising:a developer bearing member (70) configured to carry a developer for developing an electrostatic latent image formed on an image bearing member (1);a regulating blade (36) made of resin, the regulating blade (36) being (i) arranged in non-contact with the developer bearing member (70), (ii) arranged to face the developer bearing member (70) and (iii) configured to regulate an amount of the developer to be carried on the developer bearing member (70); anda development frame member (30) made of resin including an attaching portion (41) for attaching the regulating blade (36),characterized in thatthe regulating blade (36) includes a force receiving portion (37) for receiving a force for warping the regulating blade (36) in such a manner that a gap (G) between the developer bearing member (70) supported by the development frame member (30) and the regulating blade (36) attached to the attaching portion (41) is adjusted to within a predetermined range along a longitudinal direction of the developer bearing member (70); andthe regulating blade (36) is fixed to the attaching portion (41) in a state in which the regulating blade (36) is warped by the force received by the force receiving portion (37) and the gap (G) is within the predetermined range over the longitudinal direction of the developer bearing member (70).
- The development device (3) according to claim 7, wherein the regulating blade (36) is fixed to the attaching portion (41) in a state in which the regulating blade (36) is warped in a direction in which a relative position of the regulating blade (36) with respect to the developer bearing member (70) supported by the development frame member (30) is adjusted.
- The development device (3) according to claim 7 or claim 8, wherein (i) the absolute value of a difference between a maximum value of the gap (G) and a median value of the gap (G) is less than or equal to 10% of the median value of the gap (G), and (ii) the absolute value of a difference between a minimum value of the gap (G) and the median value of the gap (G) is less than or equal to 10% of the median value of the gap (G).
- The development device (3) according to any one of claims 7 to 9, wherein the regulating blade (36) is attached to the attaching portion (41) with an adhesive (A).
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JP2017105987 | 2017-05-29 | ||
JP2018077955A JP7118715B2 (en) | 2017-05-29 | 2018-04-13 | Developing device manufacturing method |
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EP (1) | EP3432076B1 (en) |
JP (3) | JP7118715B2 (en) |
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JPS63109960U (en) * | 1987-01-07 | 1988-07-15 | ||
JPH05323230A (en) * | 1992-05-26 | 1993-12-07 | Kyocera Corp | Image device |
JP3103548B1 (en) * | 1999-10-29 | 2000-10-30 | キヤノン株式会社 | Reproduction method of process cartridge |
JP2004077758A (en) * | 2002-08-16 | 2004-03-11 | Canon Inc | Developing device and processing cartridge |
JP2004082467A (en) * | 2002-08-26 | 2004-03-18 | Nippon Sheet Glass Co Ltd | System and method for assembling optical writing head |
JP4819427B2 (en) * | 2005-07-15 | 2011-11-24 | 株式会社リコー | Image forming apparatus, image forming method, and process cartridge |
JP2007241022A (en) * | 2006-03-10 | 2007-09-20 | Seiko Epson Corp | Method for fixing convergence lens array |
US7463854B2 (en) * | 2006-06-23 | 2008-12-09 | Canon Kabushiki Kaisha | Developing apparatus, processing cartridge, and image forming apparatus |
JP2008080758A (en) * | 2006-09-29 | 2008-04-10 | Seiko Epson Corp | Method for manufacturing printer head and printer head manufacturing machine |
JP2009265360A (en) * | 2008-04-25 | 2009-11-12 | Konica Minolta Business Technologies Inc | Developing apparatus and image forming apparatus |
RU2593437C2 (en) * | 2011-11-09 | 2016-08-10 | Кэнон Кабусики Кайся | Cartridge and unit |
JP5817467B2 (en) * | 2011-11-24 | 2015-11-18 | 富士ゼロックス株式会社 | Image forming method |
KR101896052B1 (en) * | 2012-04-19 | 2018-09-06 | 에이치피프린팅코리아 주식회사 | developing device and electrophotographic image forming apparatus using the same |
JP5761579B2 (en) * | 2012-10-29 | 2015-08-12 | コニカミノルタ株式会社 | Mounting structure for plate members |
EP2775355A3 (en) | 2013-03-05 | 2018-01-17 | Canon Kabushiki Kaisha | Developing device |
JP2014215466A (en) * | 2013-04-25 | 2014-11-17 | キヤノン株式会社 | Developing device and image forming apparatus |
JP6253300B2 (en) * | 2013-08-09 | 2017-12-27 | キヤノン株式会社 | Developing device and process cartridge |
-
2018
- 2018-04-13 JP JP2018077955A patent/JP7118715B2/en active Active
- 2018-05-25 EP EP18174443.4A patent/EP3432076B1/en active Active
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JP2018200462A (en) | 2018-12-20 |
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JP2022141974A (en) | 2022-09-29 |
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JP7118715B2 (en) | 2022-08-16 |
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