WO2016036164A1 - Appareil de développement - Google Patents

Appareil de développement Download PDF

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Publication number
WO2016036164A1
WO2016036164A1 PCT/KR2015/009302 KR2015009302W WO2016036164A1 WO 2016036164 A1 WO2016036164 A1 WO 2016036164A1 KR 2015009302 W KR2015009302 W KR 2015009302W WO 2016036164 A1 WO2016036164 A1 WO 2016036164A1
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WO
WIPO (PCT)
Prior art keywords
developer
blade
discharge
magnet
case
Prior art date
Application number
PCT/KR2015/009302
Other languages
English (en)
Korean (ko)
Inventor
이와타나오야
Original Assignee
삼성전자 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2015166599A external-priority patent/JP6385903B2/ja
Application filed by 삼성전자 주식회사 filed Critical 삼성전자 주식회사
Priority to US15/504,949 priority Critical patent/US10012928B2/en
Publication of WO2016036164A1 publication Critical patent/WO2016036164A1/fr

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/06—Developing
    • 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
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge

Definitions

  • the developing apparatus is disclosed.
  • JP2014-115324 describes a developing apparatus for discharging old developer through a developer outlet.
  • the developer scattered in the developer accommodating chamber may unintentionally discharge from the developer outlet through the flow of air due to an increase in the internal pressure. Accordingly, in the technical field, it is required to suppress excessive discharge of the developer from the developing apparatus.
  • an object of the present invention is to provide a developing apparatus capable of suppressing excessive discharge of a developer from a developer discharge port.
  • a developing apparatus includes: first and second case parts; First and second openings configured to communicate the first and second case parts with each other; A developing roller installed in the first case part; A first conveying member installed in the first case part to convey a developer introduced from the second case part through the second opening part toward the first opening part, and supplying a developer to the developing roller; A second conveying member installed in the second case portion to convey the developer introduced through the first opening toward the second opening; And a developer discharge port provided on the first case portion opposite to the second opening portion, wherein the first transport member comprises: a carrying blade for transporting the developer toward the first opening portion, and the first opening portion; A counter blade positioned between the developer outlets and carrying the developer toward the first opening, wherein a gap is provided between the counter blade and an inner wall of the first case portion, and the counter is located within the first case portion.
  • the cross-sectional area of the discharge path of the developer from the blade to the developer discharge port changes as it travels along the discharge path.
  • the cross-sectional area of the discharge path may decrease in stages as it approaches the developer outlet.
  • the discharge path includes a first path part and a second path part adjacent to the first path part and located at the developer discharge port side than the first path part, wherein the first path part of the first carrying member is provided. If the cross-sectional area of the portion located at is A, and the cross-sectional area of the second path portion is B, the relation A> B can be satisfied.
  • the cross-sectional area of the discharge path may be continuously small as it approaches the developer outlet.
  • the difference between the cross-sectional area of the discharge path and the cross-sectional area of the first conveying member may be smaller as it approaches the developer outlet.
  • part which forms the said discharge path among the inner walls of the said 1st case part in the said discharge path is called C, and in the said discharge path, the said 1st conveyance member
  • the gap between the upper end of the upper surface of the first case part and the upper surface of the portion of the inner wall of the first case part forming the discharge path is D, a relationship of C> D may be satisfied.
  • a magnet for attracting the developer is provided inside the developing roller, and the developing apparatus is provided at a position between the counter blade side end of the magnet and the counter blade in an extending direction of the first conveying member. And a developer retention member for retaining the developer.
  • the developer retention member includes a magnetic material and may be mounted in the first case portion.
  • the first conveying member further includes a support shaft on which an outer circumferential surface is provided with the conveying blade, a large diameter portion having a larger outer diameter is provided at a position between the counter blade side end of the magnet of the support shaft and the counter blade.
  • the developer retention member can be implemented by the large diameter portion.
  • the conveying blade may have a small diameter portion having a small outer diameter at a position between the counter blade side end of the magnet and the counter blade, and the developer retention member may be implemented by the small diameter portion.
  • the first conveying member further includes a support shaft on which an outer circumferential surface is provided with the conveying blade, wherein the support shaft is not provided with a conveying blade without the conveying blade installed at a position between the counter blade side end of the magnet and the counter blade.
  • a developer retaining member may be implemented by the carrying blade non-installation portion.
  • the first conveying member further includes a support shaft, and the conveying blade is formed in a spiral shape on an outer circumferential surface of the support shaft along an axial direction of the support shaft, and the conveying blade is formed at the counter blade side end of the magnet and the counter blade. It has a small space
  • the said developer holding member can be implement
  • the developing device may further include a magnet positioned in the discharge path to hold the developer by magnetic force.
  • the developing device may further include a developer retention member positioned at a position opposite to the magnet of the discharge path to retain the developer.
  • the first conveying member further has a supporting shaft on which an outer circumferential surface is provided with the conveying blade, wherein a portion of the supporting shaft facing the magnet is a first portion, and the first opening side is larger than the first portion of the supporting shaft.
  • a portion of is defined as a second portion, a gap between an upper surface of a portion of the inner wall of the first case portion covering the first portion and the first portion is denoted by E, and the second portion of the inner wall of the first case portion is If the gap between the upper surface of the covering portion and the second portion is F, the relationship of E < F is satisfied, and the developer retaining member is a portion covering the first portion of the inner wall of the first case portion; It can be implemented by one site.
  • the first conveying member further includes a support shaft on which a conveying blade is installed in a spiral shape on an outer circumferential surface, and a paddle member installed at a position opposite to the magnet to connect the conveying blade in the axial direction of the support shaft.
  • the developer retention member may be implemented by the paddle member.
  • the first conveying member may have a support shaft on which an outer circumferential surface is provided with the conveying blade, and the magnet may have a region overlapping with the counter blade when viewed in the axial direction of the support shaft.
  • the conveying blade includes an upstream conveying blade and a downstream conveying blade positioned respectively at the second opening, i.e., the developer outlet, with the counter blade interposed therebetween, the upper part of the counter blade and the counter blade.
  • a gap may be provided between an inner wall of the first case part to be covered, and the magnet may be installed between the counter blade and the downstream transport blade.
  • a developing apparatus includes: first and second case parts; First and second openings configured to communicate the first and second case parts with each other; A developing roller installed in the first case part; A first conveying member installed in the first case part to convey a developer introduced from the second case part through the second opening part toward the first opening part, and supplying a developer to the developing roller; A second conveying member installed in the second case portion to convey the developer introduced through the first opening toward the second opening; A developer discharge port provided on the first case part opposite to the second opening part; And a developer retention member for retaining, by magnetic force, the developer conveyed toward the developer outlet by the first transport member.
  • the first carrying member includes a carrying blade for carrying the developer toward the first opening, and a counter blade positioned between the first opening and the developer discharge port and carrying the developer toward the first opening.
  • the cross-sectional area of the discharge path of the developer from the counter blade to the developer discharge port may be smaller in the developer discharge port than in the counter blade.
  • FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the first and second embodiments.
  • FIG. 2 is a cross-sectional view in the vertical direction illustrating the developing unit of FIG. 1.
  • FIG 3 is a cross-sectional view showing a schematic configuration of a developing unit according to the first embodiment.
  • FIG. 4 is a cross-sectional view showing a schematic configuration around a discharge path of a developing unit.
  • 5 is a graph showing a measurement result of the amount of discharge of the developer when the cross-sectional area of the discharge path is changed.
  • FIG. 6 is a graph showing a measurement result of the amount of discharge of the developer when the amount of overlap between the first discharge blade and the second path portion is changed.
  • FIG. 7 is a graph showing a measurement result of the amount of discharge of the developer when the gap between the discharge path and the first conveying member is changed.
  • FIG. 8 is a sectional view showing a schematic configuration of a developing unit according to a modification of the first embodiment.
  • FIG. 9 is a cross-sectional view illustrating a schematic configuration of a developing unit according to a second embodiment.
  • 10 is a graph showing measurement results of developer emissions when the magnets for stay are installed or not.
  • FIG. 11 is a cross-sectional view illustrating a schematic configuration of a developing unit according to a first modification of the second embodiment.
  • 15 is a cross-sectional view illustrating a schematic configuration of a developing unit according to a third embodiment.
  • FIG. 16 is a partially enlarged view showing a schematic configuration around a magnet for staying of a developing unit according to a third embodiment.
  • FIG. 18 is a cross-sectional view illustrating a schematic configuration of a developing unit according to a second modification of the third embodiment.
  • 19 is a partially enlarged view showing a paddle member according to a second modification of the third embodiment.
  • 20 is a graph showing the measurement results of the emission amount of the developer.
  • 21 is a sectional view showing a schematic configuration of a developing unit according to a fourth embodiment.
  • FIG. 22 is a partially enlarged view showing a schematic configuration around a magnet for staying of a developing unit according to a fourth embodiment.
  • 24 is a sectional view showing a schematic configuration around a discharge path of a developing unit according to another modification.
  • the developing apparatus of the present invention includes a first carrying member, a second carrying member, a first case part, and a second case part.
  • the first conveying member stirs and conveys the developer by the conveying blade, and supplies the developer to the developing roller.
  • the second conveying member is disposed parallel to the first conveying member and stir conveys the developer in a direction opposite to the first conveying member.
  • the first case portion receives the first carrying member.
  • the second case portion houses the second carrying member.
  • the first case portion is provided with a first opening portion, a second opening portion, and a developer discharge port. The developer is transferred from the first case portion to the second case portion through the first opening portion.
  • the developer is transferred from the second case portion into the first case portion through the second opening portion.
  • the developer is discharged from the first case through the developer outlet.
  • the developer discharge port is provided at a position on one end side of the first transport member.
  • the 2nd opening part is provided in the position of the other end side of a 1st conveyance member.
  • the first opening is provided at a position between the second opening and the developer outlet.
  • the first conveying member has a counter blade installed at a position between the first opening and the developer outlet.
  • the conveying blade of the first conveying member conveys the developer from the second opening side toward the developer outlet side.
  • the counter blade carries the developer in a direction opposite to the carrying blade of the first carrying member.
  • a gap is provided between the upper portion of the counter blade and the inner wall of the first case portion covering the counter blade.
  • the cross-sectional area of the developer discharge path from the counter blade to the developer discharge port in the first case portion changes as it travels along the discharge path.
  • the carrying blade of the first carrying member carries the developer from the second opening side toward the first opening side.
  • the second carrying member carries the developer from the first opening side toward the second opening side.
  • the counter blade carries the developer from the developer discharge port side toward the first opening side.
  • the cross-sectional area of the discharge path can be reduced in stages as it approaches the developer outlet.
  • the flow direction of the air directed to the developer discharge port is largely changed so that the air flow is inhibited.
  • the developer can be separated from the air flow.
  • the discharge path is narrowed as it approaches the developer discharge port. As a result, the flow of air is impeded as it approaches the developer outlet. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed.
  • the discharge path may include a first path part and a second path part.
  • the second path portion may be adjacent to the first path portion, and may be located at the developer discharge port side than the first path portion.
  • a cross-sectional area of a portion located in the first path portion of the first transport member is referred to as A.
  • the cross-sectional area of the second path portion is referred to as B.
  • the relationship of A> B can be satisfied.
  • the stepped portion between the first path portion and the second path portion functions as a wall that blocks the flow of air.
  • the flow of air toward the developer outlet can be further suppressed. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed.
  • the cross-sectional area of the discharge path can be continuously small as it approaches the developer outlet. In this way, the discharge path is narrowed as it approaches the developer discharge port. As a result, the flow of air is impeded as it approaches the developer outlet. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed.
  • the difference between the cross-sectional area of the discharge path and the cross-sectional area of the first conveying member may be smaller as it approaches the developer outlet.
  • the flow path of air formed between the inner wall of the first case part and the first transport member becomes narrower as it approaches the developer discharge port.
  • the flow of air is impeded as it approaches the developer outlet. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed.
  • the gap between the lower end of the first conveying member and the lower surface of the portion of the inner wall of the first case part that forms the discharge path is referred to as C.
  • a gap between the upper end of the first conveyance member and the upper surface of the portion of the inner wall of the first case part that forms the discharge path is referred to as D.
  • the relationship of C> D can be satisfied.
  • the clearance between the inner wall of a 1st case part and a 1st conveyance member is made small in the upper part in which the developer in a discharge path is not accumulated. Thereby, the flow of air toward the developer outlet can be suppressed while suppressing the generation of aggregates of the developer. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed.
  • a magnet for attracting a developer may be installed inside the developing roller.
  • the developing apparatus may further include a developer retention member at a position between the counter blade side end of the magnet and the counter blade in the extending direction of the first conveying member.
  • the developer retention member can retain the developer. In this case, the developer stays in the position between the counter blade side end of the magnet and the counter blade. By retaining the developer, the flow of air to the developer outlet is suppressed. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed. Further, by providing the developer retention member at a position between the counter blade side end of the magnet and the counter blade, it is possible to suppress the influence on the image formation performed by the developing roller.
  • the developer retention member may be a magnetic body and may also be mounted in the first case portion. In this case, the developer can be easily retained by the developer retention member which is a magnetic body.
  • the first conveying member may further have a support shaft on which the conveying blade is installed.
  • the support shaft may have a large diameter portion whose outer diameter is enlarged at a position between the counter blade side end of the magnet and the counter blade.
  • the developer retention member can be realized by a large diameter portion. In this case, the carrying capacity of a developer falls in the part in which the large diameter part is provided. That is, the developer stays due to the large diameter portion. In this way, the developer can be easily retained by the large diameter portion of the support shaft.
  • the first conveying member may have a small diameter portion having a small outer diameter at a position between the counter blade side end of the magnet and the counter blade.
  • the developer retention member can be realized by the small diameter portion. In this case, the carrying capacity of a developer falls in the part in which the small diameter part is provided. That is, the developer stays by the small diameter portion. In this way, the developer can be easily retained by the small diameter portion of the first conveying member.
  • the first carrying member may further have a support shaft on which an outer circumferential surface is installed.
  • the support shaft may have a carrying blade non-installation portion in which the carrying blade is not installed at a position between the counter blade side end of the magnet and the counter blade.
  • the developer retention member may be implemented by the conveying blade non-installation portion. In this case, the carrying capacity of the developer is reduced in the carrying blade non-installation portion in which the carrying blade is not installed. That is, the developer stays in the non-installation portion of the carrying blade. In this way, the developer can be easily retained by not providing a part of the carrying blade.
  • the first carrying member may further have a support shaft.
  • the carrying blade may be installed in a spiral shape on the outer circumferential surface of the support shaft along the axial direction of the support shaft.
  • the conveying blade may have a small gap at a position between the counter blade side end of the magnet and the counter blade.
  • the small gap can be formed by narrowing the distance between adjacent conveying blades in the axial direction of the support shaft.
  • the developer retention member can be realized by the small space. In this case, the conveyance speed of a developer falls in the small space
  • the developing apparatus of the present invention includes a first carrying member, a second carrying member, a first case part, and a second case part.
  • the first conveying member stirs and conveys the developer by the conveying blade, and supplies the developer to the developing roller.
  • the second conveying member is disposed parallel to the first conveying member and stir conveys the developer in a direction opposite to the first conveying member.
  • the first case portion receives the first carrying member.
  • the second case portion houses the second carrying member.
  • the first case portion is provided with a first opening portion, a second opening portion, and a developer discharge port. The developer is transferred from the first case portion to the second case portion through the first opening portion.
  • the developer is transferred from the second case portion into the first case portion through the second opening portion.
  • the developer is discharged from the first case portion through the developer discharge port.
  • the developer discharge port is provided at a position on one end side of the first transport member.
  • the 2nd opening part is provided in the position of the other end side of a 1st conveyance member.
  • the first opening is provided at a position between the second opening and the developer outlet.
  • the first conveying member has a counter blade installed at a position between the first opening and the developer outlet.
  • the conveying blade of the first conveying member conveys the developer from the second opening side toward the developer outlet side.
  • the counter blade carries the developer in a direction opposite to the carrying blade of the first carrying member.
  • a gap is provided between the upper portion of the counter blade and the inner wall of the first case portion covering the counter blade.
  • a magnet is installed between the counter blade and the developer outlet. The magnet generates a magnetic field in the discharge path of the developer from the counter blade to the developer discharge port.
  • the carrying blade of the first carrying member carries the developer from the second opening side toward the first opening side.
  • the second carrying member carries the developer from the first opening side toward the second opening side.
  • the counter blade carries the developer from the developer discharge port side toward the first opening side.
  • the developer circulates between the first case portion and the second case portion.
  • the developer moves over the counter blade from the first opening side toward the developer discharge port side.
  • the developer that has crossed the counter blade is discharged out of the first case through the developer outlet.
  • a magnet is installed between the counter blade and the developer discharge port. This magnet generates a magnetic field in the discharge path of the developer.
  • the magnet holds the developer by magnetic force and keeps the developer in the discharge path. In this way, by retaining the developer, the path of the developer to the developer outlet is narrowed, and the flow of air toward the developer outlet is suppressed. Therefore, excessive discharge of the developer from the developing apparatus can be suppressed.
  • the magnet installed between the counter blade and the developer outlet may be a multipole magnetized type.
  • the north pole and the south pole of this magnet can be alternately arranged along the discharge direction of the developer in the discharge path.
  • the developer stays in the shape of a band under the influence of the magnetic force lines generated between the adjacent N and S poles.
  • the strip of the developer remaining therein extends in a direction crossing (orthogonal) with respect to the discharge direction of the developer. Since a plurality of N poles and S poles are alternately provided, a plurality of bands of the developer are formed along the discharge direction of the developer. Therefore, the flow of air toward the developer outlet is suppressed by the band of the developer formed in plural. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed.
  • the developing apparatus may further include a developer retention member for retaining the developer at a position facing the magnet in the discharge path.
  • the developer stays at the position facing the magnet by the developer retention member.
  • the first conveying member may further have a support shaft on which the conveying blade is installed on an outer circumferential surface thereof.
  • part which opposes a magnet among the support shafts is called 1st site
  • the part of a 1st opening side rather than a 1st part of a support shaft is called 2nd site
  • part is E.
  • part is called F.
  • the developer retention member may be implemented by a portion covering the first portion of the inner wall of the first case portion and the first portion.
  • the gap between the inner wall of the first case portion and the support shaft is narrowed at the portion facing the magnet.
  • the first carrying member may further have a support shaft and a paddle member.
  • the carrying blade may be installed in a spiral shape on the outer circumferential surface of the support shaft.
  • the paddle member may be installed at a position opposite the magnet.
  • the paddle member may connect between the carrying blades in the axial direction of the support shaft.
  • the developer retention member may be implemented by a paddle member.
  • the developing apparatus includes a first carrying member, a second carrying member, a first case part, and a second case part.
  • the first conveying member stirs and conveys the developer by the conveying blade, and supplies the developer to the developing roller.
  • the second conveying member is disposed parallel to the first conveying member and stir conveys the developer in a direction opposite to the first conveying member.
  • the first case portion receives the first carrying member.
  • the second case portion houses the second carrying member.
  • the first case portion is provided with a first opening portion, a second opening portion, and a developer discharge port. The developer is transferred from the first case portion to the second case portion through the first opening portion.
  • the developer is transferred from the second case portion into the first case portion through the second opening portion.
  • the developer is discharged from the first case part through the developer discharge port.
  • the developer discharge port is provided at a position on one end side of the first transport member.
  • the 2nd opening part is provided in the position of the other end side of a 1st conveyance member.
  • the first opening is provided at a position between the second opening and the developer outlet.
  • the first conveying member further includes a counter blade and a support shaft on which the conveying blade and the counter blade are installed on the outer circumferential surface.
  • the counter blade is installed at a position between the first opening and the developer outlet.
  • the conveying blade of the first conveying member has an upstream conveying blade and a downstream conveying blade.
  • the upstream conveying blade is provided on the second opening side rather than the counter blade.
  • the downstream conveying blade is installed on the developer outlet side rather than the counter blade.
  • the upstream conveying blade and the downstream conveying blade convey the developer from the second opening side toward the developer discharge port side.
  • the counter blade carries the developer in the opposite direction to the upstream conveying blade and the downstream conveying blade.
  • a gap is provided between the upper portion of the counter blade and the inner wall of the first case portion covering the counter blade.
  • a magnet is installed between the counter blade and the downstream conveying blade. The magnet has an area overlapping with the counter blade when viewed along the axial direction of the support shaft of the first carrying member.
  • the carrying blade of the first carrying member carries the developer from the second opening side toward the first opening side.
  • the second carrying member carries the developer from the first opening side toward the second opening side.
  • the counter blade carries the developer from the developer discharge port side toward the first opening side.
  • the developer circulates between the first case portion and the second case portion.
  • the developer moves over the counter blade from the first opening side toward the developer discharge port side.
  • the developer that has crossed the counter blade is discharged out of the first case through the developer outlet.
  • a magnet is provided between the counter blade and the downstream conveying blade. This magnet generates a magnetic field in the discharge path of the developer. The magnet holds the developer by magnetic force and keeps the developer in the discharge path.
  • the magnet installed between the counter blade and the downstream conveying blade may be double sided magnetized.
  • the north pole of this magnet can face the counter blade side and the south pole can face the downstream conveying blade side.
  • the north pole of the magnet may face the downstream conveying blade side and the south pole may face the counter blade side.
  • the developer stays in a band shape under the influence of the magnetic force lines generated between the N pole and the S pole of the magnet.
  • the strip of the developer remaining therein extends in a direction crossing (orthogonal) with respect to the discharge direction of the developer. Therefore, the flow of air toward the developer discharge port is suppressed by the band of the developer remaining. Therefore, excessive discharge of the developer from the developing apparatus can be further suppressed.
  • the image forming apparatus 1 includes a recording medium conveying unit 10, a transfer unit 20, a photosensitive drum 30, four developing units (developing apparatus) 100, and fixing Unit 40.
  • the recording medium carrying unit 10 houses a sheet of paper P as a recording medium on which an image is finally formed. In addition, the recording medium carrying unit 10 carries the paper P onto the recording medium carrying path. The paper P is stacked in the cassette. The recording medium conveying unit 10 makes the paper P reach the secondary transfer area R at the timing when the toner image transferred to the paper P reaches the secondary transfer area R.
  • the transfer unit 20 carries the toner image formed by the developing unit 100 to the secondary transfer area R for secondary transfer onto the paper P.
  • FIG. The transfer unit 20 transfers the transfer belt 21, the suspension rollers 21a, 21b, 21c, 21d which suspend the transfer belt 21, and the primary transfer via the transfer belt 21 together with the photosensitive drum 30.
  • the roller 22 and the secondary transfer roller 24 through the transfer belt 21 with the suspension roller 21d are included.
  • the transfer belt 21 is an endless belt circulated by the suspension rollers 21a, 21b, 21c, and 21d.
  • the primary transfer roller 22 is provided to press the photosensitive drum 30 from the inner circumferential side of the transfer belt 21.
  • the secondary transfer roller 24 is provided to press the suspension roller 21d from the outer circumferential side of the transfer belt 21.
  • the transfer unit 20 may further include a belt cleaning device or the like for removing the toner attached to the transfer belt 21.
  • the photosensitive drum 30 is an electrostatic latent image bearing member having an image formed on its circumferential surface.
  • the photosensitive drum 30 may include, for example, an organic photoconductor (OPC).
  • OPC organic photoconductor
  • the image forming apparatus 1 is a device capable of forming a color image. According to the image forming apparatus 1, for example, four photosensitive drums 30 are provided along the moving direction of the transfer belt 21 corresponding to each color of magenta, yellow, cyan and black. On the periphery of each photosensitive drum 30, as shown in FIG. 1, the charging roller 32, the exposure unit 34, the developing unit 100, and the cleaning unit 38 are provided.
  • the charging roller 32 uniformly charges the surface of the photosensitive drum 30 to a predetermined potential.
  • the exposure unit 34 exposes the surface of the photosensitive drum 30 charged by the charging roller 32 in accordance with an image to be formed on the paper P. FIG. Thereby, the electric potential of the part exposed by the exposure unit 34 among the surfaces of the photosensitive drum 30 is changed, and an electrostatic latent image is formed.
  • Toner is supplied to the four developing units 100 from the toner tanks 36 provided corresponding to the respective developing units 100.
  • the developing unit 100 develops an electrostatic latent image formed on the photosensitive drum 30 by toner to generate a toner image.
  • Each of the four toner tanks 36 is filled with a replenishment developer in which toners of magenta, yellow, cyan and black are mixed with a carrier.
  • the cleaning unit 38 recovers the toner remaining on the photosensitive drum 30 after the toner image formed on the photosensitive drum 30 is first transferred to the transfer belt 21.
  • the cleaning unit 38 for example, a configuration may be employed in which residual toner on the photosensitive drum 30 is removed by contacting the cleaning blade with the peripheral surface of the photosensitive drum 30.
  • the antistatic lamp which resets the electric potential of the photosensitive drum 30 between the cleaning unit 38 and the charging roller 32 in the rotation direction of the photosensitive drum 30 may be arrange
  • the fixing unit 40 attaches and fixes the toner image, which is secondarily transferred from the transfer belt 21 to the paper P, to the paper P.
  • the fixing unit 40 may include, for example, a heating roller 42 and a pressure roller 44.
  • the heating roller 42 is a cylindrical member rotatable about the axis of rotation. Inside the heating roller 42, for example, a heat source such as a halogen lamp is provided.
  • the pressure roller 44 is a cylindrical member rotatable about the axis of rotation. The pressure roller 44 is installed to press the heating roller 42.
  • a heat resistant elastic layer such as silicone rubber is provided on the outer circumferential surfaces of the heating roller 42 and the pressure roller 44. The toner image is melted and fixed to the paper P by passing the paper P through the fixing nip which is a contact area between the heating roller 42 and the pressure roller 44.
  • the image forming apparatus 1 is provided with discharge rollers 52 and 54 for discharging the paper P on which the toner image is fixed by the fixing unit 40 to the outside of the apparatus.
  • the image signal of the image to be recorded is input to the image forming apparatus 1.
  • the control unit of the image forming apparatus 1 uniformly charges the surface of the photosensitive drum 30 to a predetermined potential by the charging roller 32 in accordance with the received image signal.
  • the control part of the image forming apparatus 1 irradiates a laser beam to the surface of the photosensitive drum 30 by the exposure unit 34, and forms an electrostatic latent image.
  • the developing unit 100 adjusts, mixes and stirs the toner and the carrier so as to have a desired mixing ratio. In this way, the developing unit 100 uniformly disperses the toner and adjusts the developer so as to give an optimum charge amount.
  • This developer is supported on the developing roller 110. Then, when the developer is transported to the region facing the photosensitive drum 30 by the rotation of the developing roller 110, toner among the developer supported on the developing roller 110 is formed on the peripheral surface of the photosensitive drum 30.
  • the latent electrostatic image is developed by moving to the latent electrostatic image.
  • the toner image thus formed is first transferred from the photosensitive drum 30 to the transfer belt 21 in a region where the photosensitive drum 30 and the transfer belt 21 face each other.
  • the toner images formed on the four photosensitive drums 30 are sequentially stacked on the transfer belt 21 to form one laminated toner image. Then, the laminated toner image is secondarily transferred onto the paper P carried from the recording medium conveying unit 10 in the secondary transfer region R in which the suspension roller 21d and the secondary transfer roller 24 face each other.
  • the paper P on which the laminated toner image is secondarily transferred is conveyed to the fixing unit 40.
  • the paper P By passing the paper P between the heating roller 42 and the pressure roller 44 while applying heat and pressure, the laminated toner image is melted and fixed to the paper P. Thereafter, the paper P is discharged to the outside of the image forming apparatus 1 by the discharge rollers 52 and 54.
  • the belt cleaning device when the belt cleaning device is provided, the toner remaining on the transfer belt 21 after the laminated toner image is secondarily transferred onto the paper P is removed by the belt cleaning device.
  • the developing unit 100 includes a developing roller 110, a first conveyance member 120, and a second conveyance member 130.
  • the developing roller 110, the first conveying member 120, and the second conveying member 130 are installed in the developer accommodating chamber 160 formed by the case 105 of the developing unit 100.
  • the developing roller 110 is a developer carrying member which supplies toner to an electrostatic latent image formed on the circumferential surface of the photosensitive drum 30.
  • the developing roller 110 includes, for example, a developing sleeve 114 and a magnet 112 disposed inside the developing sleeve 114.
  • the developing sleeve 114 is a cylindrical member formed of a nonmagnetic metal. In the developing roller 110, only the developing sleeve 114 rotates. The magnet 112 disposed in the developing sleeve 114 is fixed to the case 105.
  • Magnet 112 has a plurality of magnetic poles.
  • the magnet 112 may be, for example, a form in which different magnetic poles are alternately disposed in an area facing the photosensitive drum 30.
  • the region facing the photosensitive drum 30 is a position facing the first conveying member 120 from a developing region for developing an electrostatic latent image formed on the photosensitive drum 30, for example.
  • the magnet 112 carries the developer by magnetic force on the developing sleeve 114. Further, in the developing region, a brush of the magnetic brush of the developer is raised to bring the magnetic brush into contact with or close to the electrostatic latent image of the photosensitive drum 30. For this reason, a pole position or a gap is arrange
  • the magnetic pole of the same polarity is disposed adjacent to the circumferential direction. Due to the polarity of the polarity, the magnetic force in the tangential direction and the normal direction with respect to the rotational direction of the developing sleeve 114 becomes small in the gap. Accordingly, the developer is peeled off from the developing sleeve 114 at a position where the developing roller 110 and the first conveying member 120 face each other with the rotation of the developing sleeve 114.
  • the layer thickness regulating member 150 is provided on the upstream side of the developing sleeve 114 in the rotational direction with respect to the position where the developing sleeve 114 and the photosensitive drum 30 of the developing roller 110 face each other.
  • the layer thickness regulating member 150 is a member that uniforms the developer adhered on the circumferential surface of the developing sleeve 114 into a layer having a uniform thickness.
  • a metal blade can be used as the layer thickness regulating member 150.
  • the developing roller 110 rotates, air may flow into the developer accommodating chamber 160.
  • the pressure in the case 105 becomes high.
  • a hole for depressurization may be provided in the case 105.
  • a filter may be installed in the desorption hole so that the developer is not discharged.
  • the first transport member 120 and the second transport member 130 stir the magnetic carrier and the non-magnetic toner constituting the developer in the developer accommodating chamber 160 to frictionally charge the carrier and the toner.
  • the case 105 includes a first case portion 105A and a second case portion 105B.
  • the first case portion 105A accommodates the developing roller 110 and the first carrying member 120.
  • the second case portion 105B accommodates the second carrying member 130.
  • the first conveying member 120 is disposed opposite to the developing roller 110 at a substantially vertical lower side.
  • the first conveying member 120 supplies the mixed stirred developer to the developing roller 110.
  • the first carrying member 120 includes a first support shaft 122 and a first carrying blade (carrying blade) 124.
  • the first support shaft 122 is rotatably supported by the first case portion 105A through a bearing (not shown).
  • the first support shaft 122 extends in a substantially horizontal direction.
  • the first conveying blade 124 is installed on the outer circumferential surface of the first support shaft 122.
  • the first carrying blade 124 has a helical inclined surface disposed along the longitudinal direction of the first support shaft 122.
  • the second conveying member 130 is disposed at a substantially vertical lower side with respect to the first conveying member 120.
  • the second conveyance member 130 plays a role of sufficiently charging the developer by mixing and stirring the developer.
  • the second conveyance member 130 conveys the charged developer to the first conveyance member 120.
  • the second carrying member 130 like the first carrying member 120, includes a second support shaft 132 and a second carrying blade 134.
  • the second support shaft 132 is rotatably supported by the second case portion 105B through a bearing (not shown).
  • the second support shaft 132 extends along the horizontal direction.
  • the second conveying blade 134 is installed on the outer circumferential surface of the second support shaft 132.
  • the second conveying blade 134 has a helical inclined surface disposed along the longitudinal direction of the second support shaft 132.
  • the first carrying member 120 and the second carrying member 130 are arranged side by side such that the first support shaft 122 and the second support shaft 132 are substantially parallel to each other.
  • the first case portion 105A and the second case portion 105B are provided adjacent to each other in the substantially vertical direction.
  • the lower portion of the first case portion 105A and the upper portion of the second case portion 105B are formed of one member (hereinafter referred to as "compartment plate 106"). That is, the partition plate 106 also functions as a part of the first case part 105A and a part of the second case part 105B.
  • the partition plate 106 separates the first conveying member 120 and the second conveying member 130.
  • the partition plate 106 is provided with a first opening portion 106a and a second opening portion 106b.
  • the developer is moved from the first case portion 105A into the second case portion 105B through the first opening 106a.
  • the developer is moved from the second case portion 105B to the first case portion 105A through the second opening 106b.
  • the first conveying member 120 conveys the developer introduced into the first case portion 105A from the second case portion 105B to the first opening portion 106a through the second opening portion 106b.
  • the second carrying member 130 carries the developer introduced into the second case portion 105B through the first opening 106a toward the second opening 106b.
  • the developer conveyed while stirring by the second carrying member 130 in the second case portion 105B is sent into the first case portion 105A through the second opening 106b.
  • the 1st conveyance blade 124 of the 1st conveyance member 120 conveys, stirring a developer toward the 1st opening part 106a side from the 2nd opening part 106b side.
  • some of the developer moves to the circumferential surface of the developing roller 110.
  • the remaining developer that does not move to the circumferential surface of the developing roller 110 is sent into the second case portion 105B through the first opening 106a.
  • the toner replenishing port 108 is provided in the second case portion 105B.
  • a toner concentration sensor (not shown) for detecting the toner concentration in the developer accommodating chamber 160 is provided near the second conveyance member 130.
  • the toner concentration in the developer accommodating chamber 160 is lowered, it is supplied from the toner tank 36 into the second case portion 105B through the developer supply portion 140 (see FIG. 1), and the toner supply opening 108. A solvent developer is supplied.
  • the developer discharge port 107 is provided in the first case portion 105A.
  • the developer deteriorated by the printing operation is discharged through the developer discharge port 107 due to a change in the volume of the developer in the developer accommodating chamber 160.
  • the structure around the developer outlet 107 is demonstrated using FIG.
  • the developer discharge port 107 is provided at a position on one end side of the first transport member 120.
  • the 2nd opening part 106b (refer FIG. 3) is provided in the position of the other end side of the 1st conveyance member 120.
  • FIG. The first opening 106a is provided at a position between the second opening 106b and the developer discharge port 107.
  • the first carrying member 120 may further include a counter blade 126, a first discharge blade 127, and a second discharge blade 128.
  • the counter blade 126 is installed at a position between the first opening portion 106a and the developer discharge port 107.
  • the counter blade 126 is installed on the outer circumferential surface of the first support shaft 122.
  • the counter blade 126 has a spiral inclined surface disposed along the longitudinal direction of the first support shaft 122.
  • the counter blade 126 carries the developer in a direction opposite to the first conveying blade 124. That is, the counter blade 126 returns the developer directed from the first opening 106a to the developer outlet 107 toward the first opening 106A.
  • a gap X is provided between the upper portion of the counter blade 126 and the inner wall 105A-1 of the first case portion 105A covering the counter blade 126.
  • the first discharge blade 127 is installed on the developer discharge port 107 side than the counter blade 126.
  • the first discharge blade 127 is installed on the outer circumferential surface of the first support shaft 122.
  • the first discharge blade 127 has a spiral inclined surface disposed along the longitudinal direction of the first support shaft 122.
  • the first discharge blade 127 carries the developer in the same direction as the first conveying blade 124. That is, the first discharge blade 127 carries the developer from the first opening 106a toward the developer discharge port 107.
  • the second discharge blade 128 is installed at the developer discharge port 107 side than the first discharge blade 127.
  • the second discharge blade 128 is installed on the outer circumferential surface of the first support shaft 122.
  • the second discharge blade 128 has a spiral inclined surface disposed along the longitudinal direction of the first support shaft 122.
  • the second discharge blade 128 carries the developer in the same direction as the first conveying blade 124. That is, the second discharge blade 128 carries the developer from the first opening 106a toward the developer discharge port 107.
  • the discharge path L is formed by the inner walls 105A-2 and 105A-3 of the first case portion 105A covering the first discharge blade 127 and the second discharge blade 128.
  • the cross section of the discharge path L may be circular. However, the discharge path L is not limited to having a circular cross section.
  • the discharge path L may include a first path part L1 and a second path part L2.
  • the second path portion L2 is adjacent to the first path portion L1 and is located closer to the developer discharge port 107 than the first path portion L1.
  • the cross-sectional area of the discharge path L changes as it approaches the developer discharge port 107 from the counter blade 126. Specifically, the cross-sectional area of the discharge path L decreases in stages as it proceeds to the developer discharge port 107.
  • the cross-sectional area of the discharge path is the area of the surface orthogonal to the discharge direction of the developer.
  • the smaller stepwise means that the cross-sectional area is changed as if the stepped portion 105A-4 is formed on the inner walls 105A-2 and 105A-3 of the first case portion 105A. That is, the cross-sectional area of the first path portion L1 is larger than the cross-sectional area of the second path portion L2.
  • the cross-sectional area of the discharge path L was changed only once, it can also be changed twice or more.
  • the first discharge blade 127 is located in the first path portion L1.
  • the second discharge blade 128 is located in the second path portion L2.
  • the outer diameter of the counter blade 126 is larger than the outer diameter of the first discharge blade 127.
  • the outer diameter of the first discharge blade 127 is larger than the outer diameter of the second discharge blade 128.
  • the counter blade 126, the first discharge blade 127, and the second discharge blade 128 are generally circular when viewed along the extending direction of the first support shaft 122.
  • the counter blade 126 or the like is not circular, such as the case where an ellipse or a protrusion is provided.
  • the outer diameter of the counter blade 126 or the like refers to the length of the largest portion, that is, the largest outer diameter, when the counter blade 126 or the like is viewed along the extending direction of the first support shaft 122.
  • a cross-sectional area of the first discharge blade 127 is referred to as A.
  • the cross-sectional area of the second path portion L2 is referred to as B.
  • the cross-sectional area A and the cross-sectional area B may satisfy A> B.
  • the cross-sectional area of the counter blade 126 may be greater than or equal to the cross-sectional area of the first path portion L1.
  • the cross-sectional area of the first discharge blade 127 is a projection area when the first discharge blade 127 is viewed along the extending direction of the first support shaft 122.
  • the cross-sectional area of the counter blade 126 is also a projection area similarly to the first discharge blade 127.
  • the difference between the cross-sectional area of the discharge path L and the cross-sectional area of the first conveying member 120 may become smaller as it approaches the developer discharge port 107.
  • the cross-sectional area of the 1st conveyance member 120 is a projection area when the 1st conveyance member 120 is seen along the extension direction of the 1st support shaft 122. As shown in FIG. That is, the gap between the inner wall 105A-2 of the first case part 105A forming the first path part L1 and the first discharge blade 127 is the first case forming the second path part L2. It is larger than the clearance between the inner wall 105A-3 and the second discharge blade 128 of the portion 105A.
  • the clearance X between the inner wall 105A-1 of the first case portion 105A and the counter blade 126 is 105A-2 of the inner wall of the first case portion 105A forming the first path portion L1.
  • the gap between the first discharge blade 127 is 105A-2 of the inner wall of the first case portion 105A forming the first path portion L1.
  • route which the developer which crossed the counter blade 126 to the developer discharge port 107 was made into discharge path L.
  • the discharge path L may further include a portion in which the counter blade 126 is provided in the first path part L1 and the second path part L2.
  • the cross-sectional area of the discharge path L is changed at the position between the counter blade 126 and the first discharge blade 127, and also the position between the first discharge blade 127 and the second discharge blade 128.
  • the cross-sectional area of the discharge path L is changed at.
  • the counter blade 126 returns the developer to the first conveying blade 124 side so that the developer in the developer accommodating chamber 160 does not move to the developer discharge port 107 side.
  • the developer rides over the counter blade 126.
  • the developer over the counter blade 126 is conveyed toward the developer outlet 107 by the first discharge blade 127 and the second discharge blade 128 in the discharge path L. Then, the developer is discharged out of the case 105 through the developer outlet 107.
  • the developer moves over the counter blade 126 from the first opening 106a toward the developer discharge port 107 side. .
  • the developer that has passed over the counter blade 126 is carried by the first discharge blade 127 and the second discharge blade 128 and discharged to the outside of the case 105 through the developer discharge port 107.
  • the cross-sectional area of the discharge path L of the developer from the counter blade 126 to the developer discharge port 107 changes as it travels along the discharge path L. As shown in FIG. Therefore, in the cross-sectional area change portion, the flow direction of air from the counter blade 126 side toward the developer discharge port 107 is changed, and the flow of air is disturbed.
  • the cross-sectional area of the discharge path L may be reduced in stages as it approaches the developer discharge port 107.
  • the cross-sectional area of the discharge path L is changed step by step at the connection portion between the first path part L1 and the second path part L2.
  • the flow direction of air toward the developer discharge port 107 is greatly changed, and the flow of air is inhibited.
  • the developer can be separated from the air flow by changing the air flow direction.
  • the discharge path L can be narrowed as it approaches the developer discharge port 107. As a result, the air flow is inhibited as the developer outlet 107 approaches. Therefore, excessive discharge of the developer from the developing unit 100 can be further suppressed.
  • the diameter at the first stage of the discharge path L was 19 mm
  • the diameter at the second stage was 15 mm
  • the diameter at the third stage was 11 mm.
  • the clearance between the discharge blade and the discharge path L carrying the developer toward the developer discharge port 107 in the discharge path L was 1.5 mm.
  • the discharge amount of the developer when the developing unit 100 was operated for 3 minutes was measured.
  • emission does not contain the developer discharged
  • the cross-sectional area of the first discharge blade 127 is referred to as A.
  • FIG. The cross-sectional area of the second path portion L2 is referred to as B.
  • A> B is satisfied.
  • the stepped portion 105A-4 between the first path portion L1 and the second path portion L2 functions as a wall that blocks the flow of air. Thereby, the flow of the air toward the developer discharge port 107 can be further suppressed, and excessive discharge of the developer from the developing unit 100 can be further suppressed.
  • the difference between the cross-sectional area of the discharge path L and the cross-sectional area of the first conveying member 120 may become smaller as it approaches the developer discharge port 107.
  • the flow path of air formed between the inner walls 105A-2 and 105A-3 of the first case portion 105A, the first discharge blade 127 and the second discharge blade 128 is a developer discharge port. As it approaches 107, it narrows. As a result, the air flow is inhibited as the developer outlet 107 approaches. Therefore, excessive discharge of the developer from the developing unit 100 can be further suppressed.
  • the discharge amount of the developer is reduced as the gap between the discharge path L and the first conveyance member 120 decreases. In this way, the discharge amount of the developer can be reduced by reducing the difference between the cross-sectional area of the discharge path L and the cross-sectional area of the first conveying member 120.
  • the developing unit 100A according to the present modification is characterized by a gap between the first discharge blade 127 and the inner wall of the first case portion 105A. Specifically, the gap between the lower end of the first discharge blade 127 and the lower surface 105A-2a of the inner wall 105A-2 of the first case portion 105A forming the first path portion L1 is defined as C. It is called.
  • a gap between the upper end of the first discharge blade 127 and the upper surface 105A-2a of the inner wall 105A-2 of the first case portion 105A forming the first path portion L1 is referred to as D.
  • the gap C and the gap D satisfy the relationship of C> D.
  • the gap between the second discharge blade 128 and the inner wall 105A-3 of the first case portion 105A forming the second path portion L2 is the same as that of the first discharge blade 127 side. Can satisfy the relationship.
  • the developing unit 100 In the case where the developing unit 100 is operated, it is conceivable that a developer aggregate occurs when the inner wall 105A-2 of the first case portion 105A and the first discharge blade 127 contact with each other in the presence of the developer. Can be. For this reason, the clearance gap D between the inner wall 105A-2 of the 1st case part 105A and the 1st discharge blade 127 is made small in the upper part in which the developer in the 1st path part L1 does not collect. . Thereby, the flow of air toward the developer outlet 107 can be suppressed while suppressing generation of aggregates of the developer. Therefore, excessive discharge of the developer from the developing unit 100 can be further suppressed.
  • the developing unit 100B according to the present embodiment further includes a staying magnet (developer retaining member) 170 as compared with the developing unit 100 according to the first embodiment.
  • the staying magnet 170 is installed in the installation area S.
  • the installation area S is an area between the counter blade 126 side end part of the magnet 112 provided in the developing roller 110 in the extending direction of the 1st conveyance member 120, and the counter blade 126.
  • the staying magnet 170 is mounted on the surface of the inner wall 105A-1 of the first case portion 105A.
  • the staying magnet 170 is formed of a magnetic body and attracts the developer by magnetic force. That is, the staying magnet 170 retains the developer directed to the counter blade 126 side by magnetic force.
  • the staying magnet 170 in the installation area S, the developer will stay in the installation area S.
  • FIG. By keeping the developer in the first case portion 105A, the flow of air toward the developer discharge port 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100B can be further suppressed. Further, by providing the staying magnet 170 at a position between the counter blade 126 side end of the magnet 112 and the counter blade 126, the staying magnet 170 is performed by the developing roller 110. Influence on image formation can be suppressed.
  • a staying magnet 170 formed of a magnetic material is used.
  • the developer can be easily retained by the staying magnet 170 formed of a magnetic body.
  • the measurement result of the discharge amount of the developer discharged through the flow of air will be described.
  • FIG. 10 the amount of developer discharged when the staying magnet 170 is provided and when it is not provided is shown.
  • the developer discharge amount when the developing unit 100B was operated for 3 minutes was measured.
  • emitted by increasing the amount of the developer in the developer accommodation chamber 160 is not contained in the developer which measured discharge
  • the amount of developer discharge is about 1/20 as compared with the case where the staying magnet 170 is not provided (none). It became. In this way, by providing the staying magnet 170, the amount of the developer discharged from the developer discharge port 107 by the flow of air can be suppressed.
  • the developing unit 100C which concerns on this modification is a large diameter part (developer retention member) 122a instead of the staying magnet 170 of the developing unit 100B which concerns on 2nd Embodiment. ).
  • the large diameter part 122a is provided in the installation area S.
  • the large diameter part 122a is formed by enlarging a part outer diameter of the 1st support shaft (support shaft) 122 in the installation area S. As shown in FIG.
  • the carrying capacity of a developer falls in the part where the large diameter part 122a is provided. That is, the developer stays by the large diameter portion 122a. In this manner, the developer can be easily held by the large diameter portion 122a of the first support shaft 122.
  • the flow of air toward the developer discharge port 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100C can be further suppressed.
  • the developing unit 100D which concerns on this modification is a small diameter part (developer retention member) 124a instead of the staying magnet 170 of the developing unit 100B which concerns on 2nd Embodiment. It is provided.
  • the small diameter part 124a is provided in the installation area S.
  • the small diameter part 124a is formed by making the one outer diameter of the 1st conveying blade 124 small in the installation area S.
  • the carrying capacity of a developer falls in the part where the small diameter part 124a is provided. That is, the developer is retained by the small diameter portion 124a. In this way, the developer can be easily held by the small diameter portion 124a of the first support shaft 122.
  • the flow of air toward the developer discharge port 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100D can be further suppressed.
  • the developing unit 100E which concerns on this modification is a conveyance blade non-installation part (developer retention member) instead of the staying magnet 170 of the developing unit 100B which concerns on 2nd Embodiment. 124b.
  • the conveying blade non-installation part 124b is installed in the installation area S.
  • the carrying blade non-installation part 124b is a part in which the 1st carrying blade 124 is not installed in the outer peripheral surface of the 1st support shaft 122 in the installation area S.
  • the conveyance capacity of the developer decreases. That is, the developer stays by the conveying blade non-installation portion 124b. In this way, the developer can be easily retained by the conveying blade non-installation portion 124b of the first support shaft 122.
  • the flow of air toward the developer discharge port 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100E can be further suppressed.
  • the developing unit 100F which concerns on this modification is a small space
  • the small spacing part 124c is provided in the installation area S.
  • interval part 124c is formed in the installation area S by narrowing the space
  • the conveyance speed of a developer falls in the small space
  • the flow of air toward the developer discharge port 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100F can be further suppressed.
  • the developing unit 100G according to the present embodiment further includes a staying magnet (magnet) 170A as compared with the developing unit 100 according to the first embodiment.
  • the staying magnet 170A is provided between the counter blade 126 and the developer discharge port 107.
  • the staying magnet 170A generates a magnetic field in the discharge path L between the counter blade 126 and the developer discharge port 107. That is, the staying magnet 170A retains the developer directed toward the developer discharge port 107 by magnetic force.
  • the staying magnet 170A is provided on the outer surface of the first case portion 105A at a position facing the first discharge blade 127 via the first case portion 105A.
  • the staying magnet 170A may cover the first discharge blade 127 over the entire circumference of the first support shaft 122 in the radial direction.
  • the staying magnet 170A may cover the circumference of the first discharge blade 127 with respect to the radial direction of the first support shaft 122 by a predetermined angle such as a half wheel.
  • the staying magnet 170A may cover the top of the first discharge blade 127.
  • the axial length of the 1st support shaft 122 in the staying magnet 170A can be made into the length more than 1 pitch of the 1st discharge blade 127.
  • the cross-sectional area of the discharge path L changes as it approaches the developer discharge port 107 from the counter blade 126. Specifically, the cross-sectional area of the first path portion L1 is larger than the cross-sectional area of the second path portion L2. In this embodiment, although the cross-sectional area of the discharge path L was changed only once, it can also be changed twice or more.
  • the staying magnet 170A is a multipole magnetized magnet.
  • the N poles and the S poles are alternately arranged along the discharge direction of the developer in the discharge path L.
  • the staying magnet 170A generates a magnetic field in the discharge path L of the developer.
  • the staying magnet 170A holds the developer by magnetic force, and retains the developer in the discharge path L.
  • FIG. In this manner, by retaining the developer, the path of the developer toward the developer outlet 107 is narrowed, and the flow of air toward the developer outlet 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100G can be suppressed.
  • the north pole and the south pole of the staying magnet 170A are alternately arranged along the discharge direction of the developer in the discharge path L.
  • the developer stays in a band shape under the influence of the magnetic force line M1 (see FIG. 16) generated between the adjacent N pole and S pole.
  • the strip of the developer remaining therein extends in a direction crossing (orthogonal) with respect to the discharge direction of the developer. That is, the strip of the developer which stays extends to surround the outer circumference of the first discharge blade 127. Since a plurality of N and S poles are alternately provided, a plurality of bands of the developer is formed along the discharge direction of the developer. Therefore, the flow of air toward the developer discharge port 107 is suppressed by the band of the developer formed in plural. Therefore, excessive discharge of the developer from the developing unit 100G can be further suppressed.
  • the cross-sectional area of the discharge path L decreases in stages as it approaches the developer discharge port 107.
  • the flow of air toward the developer outlet 107 is inhibited.
  • the developer can be separated from the air flow by changing the air flow direction. Therefore, excessive discharge of the developer from the developing unit 100G can be further suppressed.
  • the developing unit 100H according to the present modification further includes a developer retention member T1 as compared with the developing unit 100G according to the third embodiment.
  • the developer retention member T1 is provided at a position facing the staying magnet 170A in the discharge path L. As shown in FIG.
  • a portion of the first support shaft 122 that faces the staying magnet 170A is referred to as a first portion 122b.
  • the part of the 1st opening part 106a side than the 1st part 122b of the 1st support shaft 122 is called the 2nd part 122c.
  • the second portion 122c is a portion where the counter blade 126 is installed.
  • E The gap between the upper surface of the portion 105a covering the first portion 122b and the first portion 122b of the inner wall 105A-1 of the first case portion 105A is referred to as E.
  • the gap between the upper surface of the portion 105b covering the second portion 122c and the second portion 122c of the inner wall 105A-1 of the first case portion 105A is F.
  • the clearance gap E and the clearance gap F satisfy
  • the developer retention member T1 is realized by a portion 105a covering the first portion 122b of the inner wall 105A-1 of the first case portion 105A and the first portion 122b.
  • the clearance gap between the inner wall 105A-1 of the 1st case part 105A and the 1st support shaft 122 becomes narrow in the site
  • the developing unit 100J according to the present modification further includes a developer retention member T2 as compared with the developing unit 100G according to the third embodiment.
  • the developer retention member T2 is provided at a position facing the staying magnet 170A in the discharge path L. As shown in FIG.
  • the developer retention member T2 is implemented by the paddle member 127A.
  • the first discharge blade 127 is opposed to the staying magnet 170A on the first support shaft 122.
  • Paddle member 127A is a plate-like member. The paddle member 127A connects between the first discharge blades 127 in the axial direction of the first support shaft 122.
  • the paddle member 127A pushes the developer away from the first support shaft 122. That is, the paddle member 127A pushes the developer toward the staying magnet 170A side. As a result, the amount of the developer held in the staying magnet 170A increases, and the flow of air toward the developer discharge port 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100J can be further suppressed.
  • the developer retention member T1 and the developer retention member T2 are illustrated in the first and second modifications of the third embodiment, the developer retention member may be implemented in other forms.
  • the developer retention member is formed of a first discharge blade 127 provided at a position opposed to the retention magnet 170A, and having a narrow pitch (gap of the blade in the axial direction of the first support shaft 122). By making it one discharge blade 127, it may be implemented.
  • the pitch of the first discharge blade 127 is narrow, the pitch of the first discharge blade 127 is narrower than the pitch of the first conveying blade 124 provided upstream than the first discharge blade 127. it means. By narrowing the pitch of the 1st discharge blade 127, the conveyance speed of a developer falls.
  • the amount of the developer to be held in the staying magnet 170A can be increased by slowing down the conveying speed of the developer at the portion facing the staying magnet 170A. Therefore, also in this case, the flow of air toward the developer discharge port 107 is suppressed. And excessive discharge of the developer from the developing unit can be further suppressed.
  • the measurement result of the discharge amount of the developer discharged from the developer discharge port 107 by the flow of air will be described.
  • FIG. 20 when there is no staying magnet 170A, when it is the developing unit 100G in 3rd embodiment, when it is the developing unit 100H in the 1st modification of 3rd embodiment, and 3rd
  • the measurement result in the case of the developing unit 100J in the 2nd modification of embodiment is shown.
  • the measurement result when there is no staying magnet 170A is a result measured for the comparison.
  • the measurement result in the case of absence of this staying magnet 170A is the result of having measured and removed the staying magnet 170A from the developing unit 100G in 3rd Embodiment.
  • the discharge amount of the developer per minute when the developing unit was operated using this developing unit was measured.
  • emitted by increasing the amount of the developer in the developer accommodation chamber 160 is not contained in the developer which measured discharge
  • the developing unit 100G in the third embodiment having the staying magnet 170A was significantly reduced in the amount of the developer than the developing unit not having the staying magnet 170A.
  • the developing unit 100H of the first modification having the developer retaining member T1 had a smaller discharge amount of the developer than the developing unit 100G in the third embodiment.
  • the developing unit 100J of the second modification having the developer retaining member T2 had a smaller discharge amount of the developer than the developing unit 100G in the third embodiment.
  • the developing unit 100K according to the present embodiment further includes a staying magnet (magnet) 170B as compared with the developing unit 100 according to the first embodiment.
  • the first support shaft 122 is provided with a first transport blade (upstream transport blade) 124 upstream than the counter blade 126, and the first discharge blade ( A downstream conveying blade 127 and a second discharge blade (downstream conveying blade) 128 are installed. That is, the upstream conveying blades 124 and the downstream conveying blades 127 and 128 are located on the second opening 106b side and the developer discharge port 107 side with the counter blade 126 interposed therebetween.
  • the staying magnet 170B is installed between the counter blade 126 and the first discharge blade 127. The staying magnet 170B retains the developer directed toward the developer discharge port 107 by magnetic force.
  • the staying magnet 170B is an annular member having a hole 171.
  • the inner diameter G of the portion 105A-1 covering the counter blade 126 is the inner diameter H of the portion 105A-2 covering the first discharge blade 127.
  • the stepped portion 105c is disposed on the inner wall of the first case portion 105A at a boundary portion between the portion 105A-1 covering the counter blade 126 and the portion 150A-2 covering the first discharge blade 127. Is formed.
  • the staying mat 107B is attached to the stepped portion 105c. Thereby, positioning of the staying magnet 170B can be performed easily. In addition, the staying magnet 170B can be easily fixed to the first case portion 105A.
  • the inner diameter H of the portion 105A-2 covering the first discharge blade 127 in the first case portion 105A is larger than the diameter of the hole 171 of the staying magnet 170B. That is, the inner circumferential side edge of the staying magnet 170B is more toward the first support shaft 122 side than the inner wall of the portion 105A-2 covering the first discharge blade 127 in the first case portion 105A. Is extended.
  • the diameter of the hole 171 of the staying magnet 170B is larger than the outer diameter of the first discharge blade 127 and the outer diameter of the second discharge blade 128. Accordingly, the first support shaft 122 can pass through the hole 171 of the staying magnet 170 from the side where the second discharge blade 128 is installed.
  • the diameter of the hole 171 of the staying magnet 170B is smaller than the outer diameter of the counter blade 126. That is, the staying magnet 170B has a region overlapping with the counter blade 126 when viewed along the axial direction of the first support shaft 122. Specifically, the edge portion of the hole 171 of the staying magnet 170B and the outer peripheral edge portion of the counter blade 126 overlap.
  • the area where the counter blade 126 passes when the counter blade 126 is rotated is referred to as the rotation trajectory K.
  • the magnetic field generating region M2 on which the magnetic field of the staying magnet 170B acts and the rotation trajectory K overlap. That is, the distance (axial distance of the 1st support shaft 122) between the counter blade 126 and the staying magnet 170B is set so that the magnetic field generation area
  • the developer held by the staying magnet 170B the developer that has dug into the rotation trajectory K is transported to the first opening portion 106a by the rotating counter blade 126. That is, excessive retention of the developer at the portion of the staying magnet 170B is suppressed.
  • the distance between the counter blade 126 and the staying magnet 170B is set to a distance at which the excess developer held by the staying magnet 170B can be transported to the first opening 106a by the counter blade 126. It can be said.
  • the staying magnet 170B is a double-sided magnetized magnet.
  • the staying magnet 170B may be disposed such that the N pole faces the counter blade 126 side and the S pole faces the first discharge blade 127 side.
  • the staying magnet 170B may be disposed such that the N pole faces the first discharge blade 127 side and the S pole faces the counter blade 126 side.
  • the cross-sectional area of the discharge path L changes as it approaches the developer discharge port 107 from the counter blade 126. Specifically, the cross-sectional area of the first path portion L1 is larger than the cross-sectional area of the second path portion L2. In this embodiment, although the cross-sectional area of the discharge path L was changed only once, it can also be changed twice or more.
  • the measurement result of the discharge amount of the developer discharged through the developer discharge port 107 in the flow of air will be described.
  • the measurement result is shown when there is no staying magnet 170B, and when it is the developing unit 100K (the retention magnet 170B exists) in 4th Embodiment.
  • the measurement result in the case of no staying magnet 170B is the result measured for the comparison.
  • the measurement result in the case of absence of this holding magnet 170B is the result of having measured the removal magnet 170B from the developing unit 100K in 4th Embodiment, and having measured. The discharge amount of the developer per minute when the developing unit was operated using this developing unit was measured.
  • the developer which discharged by increasing the amount of the developer in the developer accommodation chamber 160 is not contained in the developer which measured discharge
  • the developing unit 100K in the fourth embodiment having the staying magnet 170B was significantly reduced in the amount of the developer than the developing unit without the staying magnet 170B.
  • the staying magnet 170B generates a magnetic field in the discharge path L of a developer.
  • the staying magnet 170B holds the developer by magnetic force, and retains the developer in the discharge path L.
  • FIG. In this manner, by retaining the developer, the path of the developer toward the developer outlet 107 is narrowed, and the flow of air toward the developer outlet 107 is suppressed. Therefore, excessive discharge of the developer from the developing unit 100K can be suppressed.
  • the developing unit 100K can retain the developer by the staying magnet 170B while conveying the excess developer retained by the staying magnet 170B toward the first opening portion 106a. have. That is, overholding of the developer by the staying magnet 170B can be suppressed.
  • the staying magnet 170B is a double-sided magnetized magnet.
  • the staying magnet 170B may be disposed such that the N pole faces the counter blade 126 side and the S pole faces the first discharge blade 127 side.
  • the staying magnet 170B may be disposed such that the N pole faces the first discharge blade 127 side and the S pole faces the counter blade 126 side.
  • the developer stays in a band shape under the influence of the magnetic force lines generated between the N pole and the S pole of the staying magnet 170B.
  • the strip of the developer remaining therein extends in a direction crossing (orthogonal) with respect to the discharge direction of the developer. That is, a band of the developer is formed along the inner circumferential surface of the hole 171 of the staying magnet 170B. Therefore, the flow of air toward the developer discharge port 107 is effectively suppressed by the band of the developer remaining. Therefore, excessive discharge of the developer from the developing unit 100K can be further suppressed.
  • the cross-sectional area of the discharge path L decreases in stages as it approaches the developer discharge port 107.
  • the flow of air toward the developer outlet 107 is inhibited.
  • the developer can be separated from the air flow by changing the air flow direction. Therefore, excessive discharge of the developer from the developing unit 100K can be further suppressed.
  • the cross-sectional area of the discharge path L can be continuously reduced as it proceeds to the developer discharge port 107. That is, as the inner circumferential surface of the first case portion 105A forming the discharge path L proceeds to the developer discharge port 107, it may be narrowed to a tapered shape. Also in this case, as described in the first embodiment and the like, the flow of air directed to the developer discharge port 107 is suppressed. Thereby, excessive discharge of the developer from the developing unit 100L can be further suppressed.
  • tandem image forming apparatus 1 shown in FIG. 1 is an example of an image forming apparatus using the developing unit 100 according to the present embodiment, and the like. It can be applied to an image forming apparatus of a system.
  • the structure of the developing unit 100 etc. is not limited to the example shown to the said embodiment, The invention can be applied to the developing unit of the various system which has the developer discharge port 107.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)

Abstract

La présente invention concerne un appareil de développement capable de supprimer une évacuation excessive d'un révélateur depuis un orifice d'évacuation de révélateur. Une première ouverture (106a) de transfert d'un révélateur d'une partie intérieure d'une première partie de boîtier (105A) à une partie intérieure d'une seconde partie de boîtier (105B), et un orifice d'évacuation de révélateur (107) permettant d'évacuer le révélateur sont disposés au niveau de la première partie de boîtier (105A). Une contre-lame (126) est disposée à un emplacement situé entre la première ouverture (106a) et l'orifice d'évacuation de révélateur (107) au niveau d'un premier élément de support (120). La contre-lame (126) transfère le révélateur dans la direction opposée d'une première lame de support (124). Un espace est préparé entre la partie supérieure de la contre-lame (126) et la première partie de boîtier. Une section transversale d'une trajectoire d'évacuation (L) du révélateur de la contre-lame (126) à l'orifice d'évacuation de révélateur (107) à l'intérieur de la première partie de boîtier (105A) est modifiée en fonction de la progression le long de la trajectoire d'évacuation (L).
PCT/KR2015/009302 2014-09-03 2015-09-03 Appareil de développement WO2016036164A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US15/504,949 US10012928B2 (en) 2014-09-03 2015-09-03 Developing apparatus

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2014-179451 2014-09-03
JP2014179451 2014-09-03
JP2015166599A JP6385903B2 (ja) 2014-09-03 2015-08-26 現像装置
JP2015-166599 2015-08-26

Publications (1)

Publication Number Publication Date
WO2016036164A1 true WO2016036164A1 (fr) 2016-03-10

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006293214A (ja) * 2005-04-14 2006-10-26 Sharp Corp 現像装置およびそれを備える画像形成装置
JP2009192701A (ja) * 2008-02-13 2009-08-27 Konica Minolta Business Technologies Inc 現像装置および画像形成装置
JP2010160205A (ja) * 2009-01-06 2010-07-22 Sharp Corp トナーカートリッジ及びこれを用いる画像形成装置
JP2010186099A (ja) * 2009-02-13 2010-08-26 Canon Inc 現像装置及び画像形成装置
JP2013025123A (ja) * 2011-07-22 2013-02-04 Kyocera Document Solutions Inc 現像装置及びそれを備えた画像形成装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006293214A (ja) * 2005-04-14 2006-10-26 Sharp Corp 現像装置およびそれを備える画像形成装置
JP2009192701A (ja) * 2008-02-13 2009-08-27 Konica Minolta Business Technologies Inc 現像装置および画像形成装置
JP2010160205A (ja) * 2009-01-06 2010-07-22 Sharp Corp トナーカートリッジ及びこれを用いる画像形成装置
JP2010186099A (ja) * 2009-02-13 2010-08-26 Canon Inc 現像装置及び画像形成装置
JP2013025123A (ja) * 2011-07-22 2013-02-04 Kyocera Document Solutions Inc 現像装置及びそれを備えた画像形成装置

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