EP0810490A1 - Vorrichtung zum Entwickeln eines latenten elektrostatischen Bildes in einem Bilderzeugungsgerät - Google Patents

Vorrichtung zum Entwickeln eines latenten elektrostatischen Bildes in einem Bilderzeugungsgerät Download PDF

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Publication number
EP0810490A1
EP0810490A1 EP97108825A EP97108825A EP0810490A1 EP 0810490 A1 EP0810490 A1 EP 0810490A1 EP 97108825 A EP97108825 A EP 97108825A EP 97108825 A EP97108825 A EP 97108825A EP 0810490 A1 EP0810490 A1 EP 0810490A1
Authority
EP
European Patent Office
Prior art keywords
roller
developer
developing
developing roller
zone
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP97108825A
Other languages
English (en)
French (fr)
Inventor
Hiroyuki Hazama
Hiroyuki Hamakawa
Masaru Watanabe
Takashi Terada
Hirotsugu Ogawa
Masanobu Maeshima
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyocera Mita Industrial Co Ltd
Original Assignee
Mita Industrial Co Ltd
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
Application filed by Mita Industrial Co Ltd filed Critical Mita Industrial Co Ltd
Publication of EP0810490A1 publication Critical patent/EP0810490A1/de
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0806—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
    • 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
    • G03G15/0808—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 supplying means, e.g. structure of developer supply roller
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements
    • G03G21/1642—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements for connecting the different parts of the apparatus
    • G03G21/1647—Mechanical connection means
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/06—Developing structures, details
    • G03G2215/0634—Developing device
    • G03G2215/0636—Specific type of dry developer device

Definitions

  • the present invention relates to a latent electrostatic image developing device for developing a latent electrostatic image to a toner image in an image farming machine such as an electrostatic copier or a laser printer.
  • a latent electrostatic image developing device of the type which develops a latent electrostatic image, formed on the peripheral surface of a photoconductor drum in an image forming machine, to a toner image by use of a developer comprising a one-component toner.
  • This type of latent electrostatic image developing device is disclosed, for example, in Japanese Laid-Open Patent Publication No. 36277/95.
  • the latent electrostatic image developing device disclosed in this publication has a development housing; a developing roller disposed in the development housing, and adapted to hold a developer on its peripheral surface in a developer holding zone and to convey the held developer to a developing zone opposite a photoconductor drum for applying the developer to a latent electrostatic image; a makeup roller disposed in the development housing, and adapted to supply a developer to the peripheral surface of the developing roller in the developer holding zone; and a developer regulating means for regulating the amount of the developer, held on the peripheral surface of the developing roller, in a developer regulating zone positioned between the developer holding zone and the developing zone.
  • the developing roller is adapted to be rotationally driven from above to below in the developing zone.
  • the developer regulating zone is positioned above the developer holding zone, so that the developer regulating means is disposed above the developing roller.
  • the developing roller is composed of a synthetic rubber material such as urethane rubber.
  • the peripheral surface of the developing roller is shaved in an upper region by the developer regulating means pressed against this surface. Its shavings are conveyed to the developing zone to damage the photosensitive layer of the photoconductor drum.
  • the developer regulating means is composed of a rubber blade, on the other hand, the rubber blade is shaven, and the shavings are carried to the developing zone, similarly damaging the photosensitive layer of the photoconductor drum.
  • a principal technical challenge for the present invention is to provide a latent electrostatic image developing device capable of preventing damage to the photosensitive layer of the photoconductor drum by shavings formed by the friction between the developing roller and the developer regulating means, while preventing the malfunction of the developer regulating means.
  • the present invention provides a latent electrostatic image developing device of an image forming machine, which comprises a development housing; a developing roller disposed in the development housing, and adapted to hold a developer on its peripheral surface in a developer holding zone and to convey the held developer to a developing zone opposite a photoconductor drum for applying the developer to a latent electrostatic image; a makeup roller disposed in the development housing, and adapted to supply a developer to the peripheral surface of the developing roller in the developer holding zone; and a developer regulating means for regulating the amount of the developer, held on the peripheral surface of the developing roller, in a developer regulating zone positioned between the developer holding zone and the developing zone; wherein
  • the present invention also provides a latent electrostatic image developing device of an image forming machine in which the peripheral speed of the makeup roller is set to be higher than the peripheral speed of the developing roller.
  • Fig. 1 schematically shows a printer 2 which has mounted thereon an embodiment of a process unit equipped with the latent electrostatic image developing device constructed in accordance with the invention.
  • the printer 2 is a compact, slow-speed laser printer for use as a printer for a word processor, and has a machine housing 20 molded from a plastic material.
  • This machine housing 20 includes an upwardly open box-shaped housing body 21, and a cover 23 mounted turnably on a shaft 22 disposed at the top of the housing body 21.
  • a process unit 4 is mounted detachably.
  • the process unit 4 has a photoconductor unit 40, and a developing unit 50, as a latent electrostatic image developing device, pivotably supported at an upper part of the photoconductor unit 40 via a support shaft 5.
  • the photoconductor unit 40 has a photoconductor support means 41.
  • the photoconductor support means 41 has a pair of side wall members 411 arranged with spacing in the back-and-forth direction (the direction perpendicular to the sheet face of Fig. 2) (only the rear side wall member is shown in Fig. 2), and a connecting member 412 which connects together lower parts of the pair of side wall members 411.
  • the so constructed photoconductor support means 41 is integrally molded from a plastic material.
  • support portions 413 having mounting holes 414 are provided.
  • the support shaft 5 made of a metal bar material, which is disposed in a development housing (to be described later on) of the developing unit 50 By inserting the support shaft 5 made of a metal bar material, which is disposed in a development housing (to be described later on) of the developing unit 50, into the mounting holes 414 provided in the support portions 413, the photoconductor unit 40 and the developing unit 50 are supported so as to be pivotable relative to each other.
  • the photoconductor unit 40 has a photoconductor drum 42 having a photosensitive layer on its peripheral surface.
  • the photoconductor drum 42 has its rotating shaft 421 rotatably supported by the pair of side wall members 411 constituting the photoconductor support means 41, and rotationally driven by a drive means (not shown) in the direction of an arrow, i.e., from below to above in a developing zone, the site of contact (the site of nip) with a developing roller (to be described later on) of the developing unit 50.
  • a charging corona discharger 43 is disposed opposite the lower peripheral surface of the photoconductor drum 42. Upstream from the charging corona discharger 43 in the direction of rotation of the photoconductor drum 42, a paper dust removing brush 44 is disposed in contact with the peripheral surface of the photoconductor drum 42.
  • a lower guide plate 451 constituting one of a pair of pre-transfer guide plates 45 for guiding a transfer sheet, which is fed from upper left in Fig. 2, toward a transfer zone 422 on the peripheral surface of the photoconductor drum 42.
  • This lower guide plate 451 is molded integrally with the pair of side wall members 411.
  • a plurality of reinforcing ribs 451b are integrally molded with spacing in the longitudinal direction (the direction perpendicular to the sheet face of Fig. 2). These reinforcing ribs 451b are adapted to contact the support shaft 5.
  • the lower guide plate 451 can be prevented from deflecting because of the contact of the reinforcing ribs 451b with the support shaft 5, even when a pressing force acts on the top surface of the lower guide plate 451 in an attempt to cause its deflection.
  • the lower guide plate 451 can also function as a connecting member for connecting together the upper parts of the pair of side wall members 411 constituting the photoconductor support means 41, thereby improving the rigidity and strength of the photoconductor support means 41.
  • the lower guide plate 451 is molded integrally with the pair of side wall members 411, so that it can maintain a highly precise positional relationship with the photoconductor drum 42 supported rotatably on the pair of side wall members 411.
  • a post-transfer guide plate 46 is disposed for guiding the transfer sheet, undergoing transfer in the transfer zone 422, to a fixing means to be described later on.
  • the post-transfer guide plate 46 is molded integrally with the pair of side wall members 411.
  • the post-transfer guide plate 46 can function as a connecting member for connecting together the pair of side wall members 411 constituting the photoconductor support means 41, thereby improving the rigidity and strength of the photoconductor support means 41.
  • the developing unit 50 as a latent electrostatic image developing device will be described.
  • the developing unit 50 in the illustrated embodiment has a development housing 51 accommodating a developer comprising a one-component toner.
  • the development housing 51 is composed of a bottom wall 511, a front side wall 512 and a rear side wall 512 (only the rear side wall is shown in Fig. 2) erected upright from the front and rear ends of the bottom wall 511 (the ends in the direction perpendicular to the sheet face of Fig. 2), and a left side wall 513. These walls are integrally molded from a plastic material, defining an agitation chamber 514 and a development chamber 515.
  • a partition wall 516 provided in the back-and-forth direction (the direction perpendicular to the sheet face in Fig. 2) is integrally molded between the agitation chamber 514 and the development chamber 515.
  • the left and right surfaces of the partition wall 516 are formed as arcuate guide surfaces 516a and 516b.
  • a connecting member 517 disposed in an upper part on the development chamber 515 side is provided integrally with the front and rear side walls 512.
  • a toner supply hole 518 is formed in the rear side wall 512 constituting the development housing 51.
  • the toner supply hole 518 is fitted with a cap 519.
  • the support shaft 5 is disposed so as to pass through the front and rear side walls 512.
  • the photoconductor unit 40 and the developing unit 50 are supported so as to be pivotable relative to each other.
  • coiled springs 52 are interposed as spring means. These coiled springs 52 urge the photoconductor support means 41 and the development housing 51 toward each other about the support shaft 5.
  • the development housing 51 is open upwards and rightwards, i.e., on the photoconductor unit 40 side.
  • a developing roller 53 Inside the development housing 51, a developing roller 53, a makeup roller 54, an agitating means 55 and a developer regulating means 56 are disposed.
  • the developing roller 53 is disposed in the development chamber 515 of the development housing 51, and includes a rotating shaft 531 mounted rotatably on the front and rear side walls 512 constituting the development housing 51, and a solid synthetic rubber roller 532 secured to the outer peripheral surface of the rotating shaft 531.
  • the rotating shaft 531 may be formed of a suitable metallic material such as stainless steel.
  • the solid synthetic rubber roller 532 is composed of a relatively flexible and conductive material, e.g., conductive solid synthetic rubber such as urethane rubber.
  • the surface roughness of the peripheral surface of the solid synthetic rubber roller 532 i.e., the 10-point average roughness Rz defined in JIS B 0601, is set at 5.0 to 12.0.
  • the volume resistivity of the solid synthetic rubber roller 532 is set at about 10 4 to 10 9 ⁇ cm.
  • the roller hardness of the solid synthetic rubber roller 532 is set at an Asker hardness of 60 to 80 in the illustrated embodiment.
  • the so constructed roller 532 of the developing roller 53 is exposed through the right-hand opening formed in the development housing 51, and positioned opposite the photoconductor drum 42.
  • the peripheral surface of the roller 532 constituting the developing roller 53 is pressed against the peripheral surface of the photoconductor drum 42 in the developing zone. At the nip in this pressed condition, the peripheral surface of the roller 532 is compressed slightly elastically.
  • the rotating shaft 531 of the developing roller 53 is rotationally driven by a drive means (not shown) in the direction of an arrow, i.e., from below to above in the developing zone, the site of contact between the roller 532 and the photoconductor drum 42.
  • the roller 532 is also rotationally driven in the direction of the arrow, so that the peripheral surface of the roller 532 is sequentially moved through a developer holding zone 533, a developer regulating zone 534, and a developing zone 535.
  • a constant voltage of 300V is applied to the rotating shaft 531 of the developing roller 53.
  • the makeup roller 54 is disposed parallel to the developing roller 53 inside the development chamber 515 of the development housing 51.
  • the makeup roller 54 includes a rotating shaft 541 mounted rotatably on the front and rear side walls 512 constituting the development housing 51, and a roller 542 secured to the outer peripheral surface of the rotating shaft 541.
  • the rotating shaft 54 like the rotating shaft 531 of the developing roller 53, may be formed of a suitable metallic material, such as stainless steel.
  • the roller 542 is composed of a foam such as silicone foam or urethane foam. The roller 542 is pressed against the roller 532 of the developing roller 53 in the developer holding zone 533, the nip between the roller 542 and the developing roller 53.
  • the hardness of the foam constituting the roller 542 of the makeup roller 54 is much smaller than the hardness of the roller 532 constituting the developing roller 53 (for example, an Asker hardness of about 35), and it is desirable that by being pressed against the roller 532 of the developing roller 53, the roller 542 be elastically compressed in the nip region by about 0.1 to 0.6 mm.
  • the roller 542 also has conductivity, and its volume resistivity is set at about 10 2 to 10 6 ⁇ cm.
  • the rotating shaft 541 of the developing roller 54 is rotationally driven by a drive means (not shown) in the direction of an arrow, i.e., from above to below in the developer holding zone 533, the nip between the roller 542 and the roller 532 of the developing roller 53.
  • the roller 542 is also rotationally driven in the direction of the arrow.
  • a constant voltage of 450V a higher voltage than the voltage applied to the developing roller 53, is applied to the rotating shaft 541 of the makeup roller 54.
  • the peripheral speed V1 of the photoconductor drum 42, the peripheral speed V2 of the developing roller 53, and the peripheral speed V3 of the makeup roller 54 are set in the relationship V1 ⁇ V2 ⁇ V3.
  • the relation between the peripheral speed V1 of the photoconductor drum 42 and the peripheral speed V2 of the developing roller 53 is set to be 1.2V1 ⁇ V2 ⁇ 2.5V1
  • the relation between the peripheral speed V2 of the developing roller 53 and the peripheral speed V3 of the makeup roller 54 is set to be 1.0V2 ⁇ V3 ⁇ 2.0V2. If the peripheral speed V2 of the developing roller 53 is less than 1.2V1, the supply of a developer to the photoconductor drum 42 will be insufficient, and the density of an image may lower.
  • the peripheral speed V2 of the developing roller 53 is less than 1.2V1, moreover, there will be a decline in the scraping action of the developing roller 53 on the non-transferred developer that adheres to the photoconductor drum 42 after transfer. Thus, the non-transferred developer cannot be removed from the photoconductor drum 42, potentially causing a so-called offset fog.
  • the peripheral speed V2 of the developing roller 53 is more than 2.5V1, on the other hand, the drive torque of the developing roller 53 will increase, possibly causing a scatter of the developer by a centrifugal force.
  • the peripheral speed V3 of the makeup roller 54 is less than 1.0V2, the supply of a developer to the developing roller 53 will be insufficient, and image density may lower.
  • peripheral speed V3 of the makeup roller 54 is less than 1.0V2, moreover, there will be a weak scraping action of the makeup roller 54 on the peripheral surface of the developing roller 53. In case the non-transferred developer adhering to the photoconductor drum 42 after transfer adheres to the developing roller 53, therefore, this adherent developer will be difficult to remove. The adherent developer may generate a ghost in a subsequent development. If the peripheral speed V3 of the makeup roller 54 is more than 2.0V2, on the other hand, the drive torque of the makeup roller 54 will increase. Simultaneously, the developer will strongly tend to rest above the nip between the makeup roller 54 and the developing roller 53, possibly causing an insufficient supply of the developer to the developing roller 53.
  • an agitating means 55 is disposed in the agitation chamber 514 of the development housing 51.
  • the agitating means 55 is disposed parallel to the makeup roller 54, and includes a rotating shaft 551 mounted rotatably on the front and rear side walls 512 constituting the development housing 51, an agitating member 552 fixed to the rotating shaft 551, and an elastic agitating sheet member 553 mounted to the agitating member 552.
  • the agitating member 552 is formed of a plastic material, and has a plurality of openings in the longitudinal direction (the direction perpendicular to the sheet face of Fig. 2).
  • the agitating sheet member 553 is formed of a flexible, elastic material, such as polyethylene terephthalate (PETP), and is secured by an adhesive or the like to the front edge of the agitating member 552.
  • PETP polyethylene terephthalate
  • the so constructed agitating means 55 is rotationally driven continuously by a drive means (not shown) in the direction of an arrow in Fig. 2.
  • the developer regulating means 56 has a flexible, elastic blade 561 to be pressed against the peripheral surface of the roller 532 constituting the developing roller 53.
  • the blade 561 is composed of, say, a stainless steel plate or a spring steel plate about 0.1 to 0.2 mm thick, and has nearly the same longitudinal dimension as the length of the roller 532 constituting the developing roller 53.
  • the blade 561 has a base end part mounted on a blade mounting portion 511a provided at the open end, on the photoconductor unit 40 side, of the bottom wall 511 constituting the development housing 51. That is, the base end part of the blade 561 is sandwiched between the blade mounting portion 511a and a press plate 562, and is fixed thereto by means of a machine screw 563. A front end part of the blade 561 is bent, and this bend is pressed against the peripheral surface of the roller 532 constituting the developing roller 53 in the developer regulating zone 534.
  • a closure 57 is mounted which covers the open top of the development housing 51 and constitutes part of the development housing 51.
  • the closure 57 is composed of a plastic material, and is secured by an adhesive to the top surfaces of the front and rear side walls 512, the left side wall 513 and the connecting member 517 that constitute the development housing 51.
  • a regulating portion 571 is integrally molded which extends in the back-and-forth direction (the direction perpendicular to the sheet face of Fig. 2) at a position opposite the makeup roller 54, and which protrudes on the development chamber 515 side.
  • the connecting member 517 constituting the development housing 51 is mounted with a sheet-like seal member 58.
  • the sheet-like seal member 58 is composed of a flexible, elastic sheet member of, say, polyethylene terephthalate (PETP), and has nearly the same length as the axial length of the roller 532 constituting the developing roller 53.
  • the sheet-like seal member 58 has one end part secured to the connecting member 517 by a securing means such as an adhesive, and has the other end part curved and elastically contacted with the peripheral surface of the roller 532 constituting the developing roller 53.
  • the so constructed sheet-like seal member 58 prevents a scatter of the developer from the opening, on the photoconductor unit 40 side, of the development housing 51 in cooperation with the blade 561 of the developer regulating means 56.
  • the so constructed process unit 4 is mounted detachably on the machine housing 20 of the printer 2, as shown in Fig. 1. That is, the cover 23 constituting the machine housing 20 of the printer 2 is turned about the shaft 22 counterclockwise in Fig. 1, whereby the top of the housing body 21 constituting the machine housing 20 is opened. Then, the process unit 4 is mounted inside the housing body 21 from above. Inside the housing body 21, a positioning means (not shown) capable of placing the photoconductor unit 40 of the process unit 4 at a predetermined position is provided. After the process unit 4 is mounted inside the housing body 21 of the machine housing 20, the cover 22 is turned about the shaft 22 clockwise in Fig. 1 to close the top of the housing body 21.
  • a laser unit 24 is disposed in a lower part of the housing body 21 constituting the machine housing 20 of the printer 2.
  • This laser unit 24 throws laser light, corresponding to print data from, say, a word processor connected to the printer 2, upon the photosensitive layer of the photoconductor drum 42 in an exposure zone 423 of the process unit 4, thereby forming a latent electrostatic image.
  • a fixing roller pair 25 is disposed downstream from the post-transfer guide plate 46. Downstream from the fixing roller pair 25, a discharge roller pair 26 is disposed. Furthermore, a copy receiving or discharge tray 27 is disposed downstream from the discharge roller pair 26.
  • a feed tray 28 for bearing a transfer sheet is disposed at an upper left part in Fig. 2. Downstream from the feed tray 28, a feed roller 29 is disposed. This feed roller 29 is rotationally driven by a drive means (not shown) in the direction of an arrow in Fig. 2. Opposite the feed roller 29, a friction pad 30 for sheet separation is disposed.
  • a non-contact transfer roller 31 is disposed opposite the photoconductor drum 42. The transfer roller 31 is formed of a conductive urethane foam, and rotatably supported on the cover 23.
  • the transfer roller 31 has opposite end parts mounted with collars (not shown) which are composed of an insulating material, such as synthetic resin, and each of which has a larger outside diameter than the diameter of the transfer roller 31. These collars are disposed in contact with the peripheral surface of the photoconductor drum 42. Thus, the transfer roller 31 is caused to follow the rotation of the photoconductor drum 42 while slipping.
  • the clearance between the peripheral surface of the transfer roller 31 and the peripheral surface of the photoconductor drum 42 is set at about 0.5 mm.
  • a constant voltage of, say, 10 ⁇ A is applied to the so constructed transfer roller 31.
  • an upper guide plate 452 constituting the other component of the pre-transfer guide plate pair 45 is disposed.
  • the printer 2 in the illustrated embodiment is constructed as described above. Its actions will be described below.
  • the above-described members start operation, and the photosensitive layer on the surface of the photoconductor drum 42 is charged substantially uniformly to a specific polarity by the charging corona discharger 43. Then, the laser unit 24 throws laser light, corresponding to the print data from the word processor or the like, upon the surface of the charged photosensitive layer of the photoconductor drum 42, thereby forming a latent electrostatic image there.
  • the latent electrostatic image formed on the photosensitive layer of the photoconductor drum 42 is developed to a toner image by the developing action of the developing unit 50.
  • the developing action of the developing unit 50 will be described in detail later on.
  • Transfer sheets laid on the feed tray 28 are fed one by one by the action of the feed roller 29 and the friction pad 30.
  • the fed transfer sheet is guided by the pre-transfer guide plate pair 45, and conveyed to the transfer zone 422 where the photoconductor drum 42 and the transfer roller 31 are opposite to each other.
  • the toner image formed on the photoconductor drum 42 is transferred to the surface of the transfer sheet.
  • the transfer sheet, having the toner image transferred thereto in this fashion, is guided by the post-transfer guide plate 46 to be carried to the fixing roller pair 25.
  • the transfer sheet having the toner image heat-fixed by the fixing roller pair 25 is discharged onto the discharge tray 27 by the discharge roller pair 26.
  • the developing action of the developing unit 50 will be described.
  • the developing roller 53, makeup roller 54 and agitating means 55 are rotationally driven by drive means (not shown) in the directions of the arrows.
  • the developer accommodated in the agitation chamber 514 is passed over the partition wall 516 while being agitated, whereafter the developer is fed into the development chamber 515 from above the makeup roller 54.
  • the amount of the developer fed into the development chamber 515 is controlled by the regulating portion 571 formed on the inner surface of the closure 57 so that this amount will not be excessive.
  • the developer so supplied by the agitating means 55 is borne on the roller 542 of the makeup roller 54, and carried to the nip between the roller 542 and the roller 532 of the developing roller 53, which is also the developer holding zone 533.
  • the makeup roller 54 and the developing roller 53 as described above, rotate in the developer holding zone 533, the nip, in the same direction, from above to below.
  • the supply of the developer from the makeup roller 54 to the developing roller 53 is adequate, preventing lack of the developer. Since the makeup roller 54 and the developing roller 53, as described above, rotate in the same direction in the developer holding zone 533, the nip, moreover, they can be driven reliably without requiring a great drive force.
  • the makeup roller 54 and the developing roller 53 rotate in the same direction, from above to below, in the developer holding zone 533, the nip, as described earlier.
  • the developer also passes through the nip, remains held on the developing roller 53, and moves to the developer regulating zone 534 and the developing zone 535.
  • the developer is fully rubbed against the makeup roller 54 and the developing roller 53 and fully charged, thus preventing the occurrence of a fog.
  • the blade 561 of the developer regulating means 56 acts on the developer held on the peripheral surface of the roller 532 of the developing roller 53 to restrict the developer held on the peripheral surface of the roller 532 to a required amount and form it into a thin layer.
  • the developer which has been regulated by the blade 561 of the developer regulating means 56 in the developer regulating zone 534 and scraped off onto the bottom wall 511 of the development housing 51, does not remain stationary, but is conveyed along the guide surface 516b of the partition wall 516, because the makeup roller 54 is rotated in the direction of the arrow.
  • the developer is held on the peripheral surface of the roller 532 constituting the developing roller 53 in the developer holding zone 533, and formed into a thin layer by the action of the blade 561 of the developer regulating means 56 in the developer regulating zone 534. Then, this developer is conveyed to the developing zone 535 in accordance with the rotation in the direction of the arrow.
  • the developer is applied to the latent electrostatic image on the electrostatic photoconductor disposed on the peripheral surface of the photoconductor drum 42, whereby the latent electrostatic image is developed to a toner image.
  • the latent electrostatic image has a non-image area charged to about +600V, and an image area charged to about +120V, and a toner as the developer is caused to adhere to the image area (reversal development).
  • the photoconductor drum 42 and the developing roller 53 are rotationally driven in the directions of the arrows in Fig. 2. In the developing zone 535, therefore, the peripheral surface of the photoconductor drum 42 and the peripheral surface of the roller 532 constituting the developing roller 53 are both moved in the same direction, from below to above.
  • peripheral speed V2 of the roller 532 and the peripheral speed V1 of the photoconductor drum 42 are set in the relationship 1.2V1 ⁇ V2 ⁇ 2.5V1, a sufficient amount of the developer is carried to the developing zone 535 by the roller 532 of the developing roller 53. Also, the rubbing action of the peripheral surface of the roller 532 on the peripheral surface of the photoconductor drum 42 properly peels off the developer that has once adhered to the non-image area of the latent electrostatic image. Hence, a satisfactory image having an appropriate development density and free from fog can be obtained.
  • the peripheral speed of the makeup roller 54 is set to be greater than the peripheral speed of the developing roller 53. Therefore, as the developer is shifted to the makeup roller 54 at the nip, the non-transferred developer adhering to the developing roller 53 during passage through the developing zone 535 cab be decreased in adherence, and recovered. Hence, a ghost ascribed to the non-transferred developer adhering to the developing roller 53 can be prevented.
  • the latent electrostatic image developing device has been described based on the embodiments in which it is applied to a printer.
  • the present invention is in no way limited to the illustrated embodiments.
  • the invention is applicable, for instance, to an electrostatic copier, and various changes or modifications are possible without departing from the scope of the technical concept of the invention.
  • the latent electrostatic image developing device Since the latent electrostatic image developing device according to the present invention is constructed as described above, it exhibits the following actions and effects:
  • the developing roller is rotationally driven from below to above in the developing zone; the developing roller and the makeup roller are both rotationally driven from above to below in the developer holding zone; and the developer regulating means is disposed below the developing roller.
  • the developer scraped off by the developer regulating means may be accumulated on the bottom wall of the development housing.
  • the makeup roller is rotationally driven from above to below in the developer holding zone, so that the scraped developer is not accumulated, but conveyed along the bottom wall of the development housing in accordance with the rotation of the makeup roller.
  • the developer is not stagnant below the nip between the developing roller and the makeup roller. This can prevent the malfunction of the developer regulating means ascribed to the stagnation of the developer below the nip between the developing roller and the makeup roller.
  • the developing roller and the makeup roller rotate in the same direction, from above to below, in the developer holding zone, the nip between the two rollers.
  • this invention permits the developing roller and the makeup roller to rotate in the same direction, from above to below, in the developer holding zone, the nip, as described earlier.
  • the developer also passes through the nip, remains held on the developing roller, and moves to the developer regulating zone and the developing zone.
  • the developer is fully rubbed against the makeup roller and the developing roller and fully charged, thus preventing the occurrence of a fog.
  • the developing roller and the makeup roller rotate in the same direction in the developer holding zone, the nip.
  • they can be driven reliably without requiring a great drive force.
  • the peripheral speed of the makeup roller is set to be greater than the peripheral speed of the developing roller. Therefore, as the developer is shifted to the makeup roller at the nip, the non-transferred developer adhering to the developing roller during passage through the developing zone can be decreased in adherence, and recovered. Hence, a ghost ascribed to the non-transferred developer adhering to the developing roller can be prevented.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
EP97108825A 1996-05-31 1997-06-02 Vorrichtung zum Entwickeln eines latenten elektrostatischen Bildes in einem Bilderzeugungsgerät Withdrawn EP0810490A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP8137307A JPH09319212A (ja) 1996-05-31 1996-05-31 画像形成機の静電潜像現像装置
JP137307/96 1996-05-31

Publications (1)

Publication Number Publication Date
EP0810490A1 true EP0810490A1 (de) 1997-12-03

Family

ID=15195631

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97108825A Withdrawn EP0810490A1 (de) 1996-05-31 1997-06-02 Vorrichtung zum Entwickeln eines latenten elektrostatischen Bildes in einem Bilderzeugungsgerät

Country Status (5)

Country Link
EP (1) EP0810490A1 (de)
JP (1) JPH09319212A (de)
KR (1) KR970076482A (de)
CN (1) CN1172287A (de)
TW (1) TW381192B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1031894A1 (de) * 1999-02-26 2000-08-30 Brother Kogyo Kabushiki Kaisha Kartusche für ein photosensitives Bestandteil
US6330410B1 (en) 1999-02-26 2001-12-11 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
EP2657786A3 (de) * 2012-04-26 2017-10-04 Canon Kabushiki Kaisha Entwicklungsvorrichtung, Prozesskartusche und Bilderzeugungsvorrichtung

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10809661B1 (en) * 2019-06-03 2020-10-20 Lexmark International, Inc. Toner cartridge having positioning features including guides extending outward from sides of the toner cartridge and an engagement member on a rear of the toner cartridge

Citations (4)

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Publication number Priority date Publication date Assignee Title
US4378158A (en) * 1979-07-16 1983-03-29 Canon Kabushiki Kaisha Developing apparatus
EP0451982A2 (de) * 1990-03-29 1991-10-16 Hiraoka H.I. Laboratory Co. Ltd. Entwicklungseinheit
JPH0744011A (ja) * 1993-07-29 1995-02-14 Toshiba Corp 現像装置並びに現像方法並びに画像形成装置
US5451713A (en) * 1989-10-13 1995-09-19 Ricoh Company, Ltd. Developing apparatus using a developer carrier capable of forming microfields

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378158A (en) * 1979-07-16 1983-03-29 Canon Kabushiki Kaisha Developing apparatus
US5451713A (en) * 1989-10-13 1995-09-19 Ricoh Company, Ltd. Developing apparatus using a developer carrier capable of forming microfields
EP0451982A2 (de) * 1990-03-29 1991-10-16 Hiraoka H.I. Laboratory Co. Ltd. Entwicklungseinheit
JPH0744011A (ja) * 1993-07-29 1995-02-14 Toshiba Corp 現像装置並びに現像方法並びに画像形成装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 095, no. 005 30 June 1995 (1995-06-30) *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1031894A1 (de) * 1999-02-26 2000-08-30 Brother Kogyo Kabushiki Kaisha Kartusche für ein photosensitives Bestandteil
US6330410B1 (en) 1999-02-26 2001-12-11 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US6411789B1 (en) 1999-02-26 2002-06-25 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US6546217B2 (en) 1999-02-26 2003-04-08 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US6690903B2 (en) 1999-02-26 2004-02-10 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US6873810B2 (en) 1999-02-26 2005-03-29 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
EP1612615A2 (de) * 1999-02-26 2006-01-04 Brother Kogyo Kabushiki Kaisha Kartusche für ein photosensitives Bestandteil
EP1612615A3 (de) * 1999-02-26 2006-02-08 Brother Kogyo Kabushiki Kaisha Kartusche für ein photosensitives Bestandteil
US7218878B2 (en) 1999-02-26 2007-05-15 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US7224923B2 (en) 1999-02-26 2007-05-29 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US7231167B2 (en) 1999-02-26 2007-06-12 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US7245850B2 (en) 1999-02-26 2007-07-17 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US7457563B2 (en) 1999-02-26 2008-11-25 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US7742720B2 (en) 1999-02-26 2010-06-22 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US7949283B2 (en) 1999-02-26 2011-05-24 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
US8121520B2 (en) 1999-02-26 2012-02-21 Brother Kogyo Kabushiki Kaisha Photosensitive member cartridge
EP2657786A3 (de) * 2012-04-26 2017-10-04 Canon Kabushiki Kaisha Entwicklungsvorrichtung, Prozesskartusche und Bilderzeugungsvorrichtung

Also Published As

Publication number Publication date
TW381192B (en) 2000-02-01
CN1172287A (zh) 1998-02-04
JPH09319212A (ja) 1997-12-12
KR970076482A (ko) 1997-12-12

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