EP2894519A1 - Verfahren zur Herstellung von Magnetrollen und System dafür - Google Patents

Verfahren zur Herstellung von Magnetrollen und System dafür Download PDF

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Publication number
EP2894519A1
EP2894519A1 EP14150471.2A EP14150471A EP2894519A1 EP 2894519 A1 EP2894519 A1 EP 2894519A1 EP 14150471 A EP14150471 A EP 14150471A EP 2894519 A1 EP2894519 A1 EP 2894519A1
Authority
EP
European Patent Office
Prior art keywords
magnetic
magnetic roller
mold
manufacturing
field distribution
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Withdrawn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
EP14150471.2A
Other languages
English (en)
French (fr)
Inventor
Ching Chi Mok
Lai Ping Lo
Zi He Yong
Hai Zhan Lao
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.)
Earth Magnets (Hong Kong) Co Ltd
Original Assignee
Earth Magnets (Hong Kong) 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 Earth Magnets (Hong Kong) Co Ltd filed Critical Earth Magnets (Hong Kong) Co Ltd
Priority to EP14150471.2A priority Critical patent/EP2894519A1/de
Publication of EP2894519A1 publication Critical patent/EP2894519A1/de
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
    • G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration

Definitions

  • the present invention relates to technology for manufacturing magnetic rollers and more particularly pertains to a method for manufacturing magnetic rollers and a system thereof.
  • magnétique rollers are regarded as an indispensable component which plays an important role.
  • the quality of magnetic rollers will directly affect the copying and printing quality.
  • the quality of magnetic rollers is mainly determined by their manufacturing technology and equipment. At present, there are mainly two methods for manufacturing magnetic rollers, namely adhesion and integral molding. To manufacture magnetic rollers by adhesion, a number of permanent magnetic strips are adhered onto a mandrel to form a magnetic roller.
  • a magnetic roller formed by adhesion has the following disadvantages: it has unstable quality and high defective rate because it is formed by adhering independent permanent magnetic strips which have different compositions and are made by different manufacturing methods; besides, it has high production costs and requires long processing time because special clamps and adhesives are required for adhering the permanent magnetic strips and assembly is required after the adhesion process; furthermore, due to the differences in the characteristics of each of the permanent magnetic strips, difficulties are encountered in material selection, shaping and sizing, and repeated trials are often needed to manufacture ideal magnetic rollers, thus resulting in long production time.
  • magnetic rollers are formed by injection molding, and the magnetic rollers formed by injection molding will then undergo demagnetization and magnetization processes to attain specific magnetic pole strength, magnetic angle and so forth.
  • magnetic rollers manufactured by injection molding in the present marketplace have equal strengths and widths for each magnetic pole; it is impossible to manufacture magnetic rollers with different strengths and widths for each magnetic pole according to customers' requirements. Due to the fact that magnetic rollers having equal strengths and widths for each magnetic pole can only be used in printers but not copiers, the application scope of magnetic rollers formed by injection molding is still limited.
  • the present invention provides a method for manufacturing magnetic rollers with the following advantages: simple manufacturing process, short production cycle, high production efficiency, low production costs, energy-saving, capable of magnetizing magnetic rollers according to specific requirements during injection molding, and easy to attain complex magnetic flux density diagrams.
  • Another object of the present invention is to provide a system which can achieve the aforementioned method for manufacturing magnetic rollers.
  • the system of the present invention is simple and reasonable in structure, convenient to operate, easy to control and has lower production costs; magnetic rollers manufactured have the advantages of low production costs and stable quality.
  • the primary object of the present invention is achieved by providing a method for manufacturing a magnetic roller which comprises the following steps: Step 1: determining number and shape of magnets required according to a desired magnetic field distribution diagram, and thereafter mounting the magnets around a cavity of a mold at corresponding positions required for attaining the desired magnetic field distribution diagram;
  • Step 2 injecting materials for manufacturing the magnetic roller into the cavity of the mold for molding to manufacture the magnetic roller; at the same time, magnetizing the magnetic roller inside the mold so that the magnetic roller manufactured has a magnetic field distribution diagram identical to the desired magnetic field distribution diagram mentioned in Step 1.
  • a metallic mandrel is embedded in the magnetic roller formed by injection molding mentioned in Step 2 to enhance mechanical strength of the magnetic roller.
  • the magnetic roller taken out from the mold can be demagnetized and thereafter magnetized again to meet the desired requirements.
  • a groove-cutting operation can be performed at a position of the magnetic roller corresponding to the special wave pattern after the magnetic roller has been taken out from the mold so as to form a special magnetic field distribution wave pattern which meets the special requirements of the special magnetic field distribution requirements. It can be seen that the present invention can manufacture magnetic rollers with extremely complex wave patterns in their magnetic field distribution diagrams.
  • shape of the cavity of the mold can also be configured according to the special magnetic field distribution wave pattern before injection molding, so that the magnetic roller formed by injection molding has a cross-section comprising concave-convex portions.
  • the magnetic roller as mentioned in Step 2 can optionally be disposed with a metallic mandrel at center thereof.
  • Materials used for manufacturing the magnetic roller can be combined particles of PA+Fe.
  • Another object of the present invention is achieved by providing a system used in the method for manufacturing magnetic rollers which comprises a mold, wherein the mold comprises a cavity and magnets; the magnets are distributed around the cavity of the mold according to a desired magnetic field distribution diagram.
  • the magnets can be permanent magnets or electromagnets. Number of the magnets can range from 2 to 10 pieces.
  • the cavity of the mold can be cylindrical in shape, but other shapes are also possible depending on actual production needs.
  • the present invention has the following advantages and effects:
  • the method for manufacturing a magnetic roller comprises the following steps:
  • Neodymium-Iron-Boron can be used as the magnets. Magnetization will be automatically performed by Neodymium-Iron-Boron without the need of temperature control and adjustment of magnetic strength, time and so forth. However, different models of materials are selected according to the magnetic strengths required. In this embodiment, N38SH model of Neodymium-Iron-Boron is selected. Each of the magnets has a length identical to that of the magnetic roller (for example, 210mm or 300mm), a width of 30mm and a height of 8mm. In this embodiment, the magnets are permanent magnets; but in other embodiments, electromagnets can also be used, wherein a magnetic yoke inside an electromagnetic coil is used to adjust voltage and size of electric current to suitable levels to produce magnetic poles.
  • the magnetic roller as mentioned in Step 2 can optionally be disposed with a metallic mandrel at center thereof.
  • Materials used for manufacturing the magnetic roller can be combined particles of PA+Fe.
  • a system for manufacturing magnetic rollers comprises a mold, wherein the mold comprises a cylindrical cavity 11; the mold further comprises four permanent magnets N1, S1, N2 and S2; the magnets are distributed around the cavity 11 of the mold according to a desired magnetic field distribution diagram.
  • Figure 1 is a cross-sectional diagram of the system.
  • the mold has a frame made of iron and a plate made of stainless steel.
  • Embodiment 1 is the same as Embodiment 1:
  • the magnetic flux densities of the six poles N21, S21, N22, S22, 02 and S23 are 90mT, 80mT, 40mT, 50mT, 10mT and 60mT respectively, wherein spacing between positions of the magnetic poles are not equal and differ greatly from each other. Therefore, number and shape of the magnets together with their positions inside the mold have all to be disposed according to the desired magnetic field distribution diagram as illustrated in Figure 5 .
  • six magnets N1a, S1 b, N2c, S2d, 0f and S3e of different sizes are asymmetrically distributed around the cavity 11.
  • the magnets each has a length identical to that of the magnetic roller (for example, 210mm or 300mm), a width of 8mm, 20mm, 10mm, 10mm, 10mm and 10mm respectively, and a height of 30mm, 25mm, 10mm, 15mm, 5mm and 20mm respectively.
  • the desired requirements are as illustrated in Figure 5 , due to errors occurred during the manufacturing process and other reasons, the magnetic flux densities of the six poles N21', S21', N22', S22', 02' and S23' of the magnetic roller taken out from the mold, as illustrated in Figure 4 , are detected to be different from the desired requirements as illustrated in Figure 5 .
  • a magnetizing cabinet can be used for magnetizing the magnetic roller; the magnetizing cabinet comprises a capacitor which can generate 6 sets of power outputs by means of a controller. These 6 sets of power outputs can generate various magnetic strengths by adjusting the voltage in order to magnetize each magnetic pole of the magnetic roller respectively. As such, different magnetic flux densities can be attained at different positions of the magnetic roller.
  • Embodiment 1 is the same as Embodiment 1: As illustrated in Figure 7 , the magnetic flux densities of the six poles N31, S31, N32, S32, 03 and S33 of the desired magnetic field distribution diagrams required are basically the same as those in Embodiment 2, except that there are two values in the pole S31 which are 40 mT and 20mT respectively. Positions of the magnetic poles are all asymmetrical and shape of each pole differs from each other greatly. Therefore, number and shape of the magnets together with their positions in the mold have to be disposed according to the desired magnetic field distribution diagram as illustrated in Figure 7 .
  • the pole S31 as shown in Figure 7 has a very special wave pattern with a recessed portion. Therefore, after the magnetic roller is taken out from the mold, as illustrated in Figure 8 , a groove 1 is cut on the magnetic roller at a position corresponding to the recessed portion of the wave pattern of the pole S31 using a datum plane 2 as the datum plane. After the groove-cutting operation, the magnetic roller can form a special magnetic field distribution wave pattern which meets the desired requirements as illustrated in the magnetic field distribution diagram in Figure 7 , resulting in a magnetic roller which has an extremely complex wave pattern in its magnetic field distribution diagram.
  • this embodiment is the same as Embodiment 1, Embodiment 2 and Embodiment 3.
  • a metallic mandrel 3 is embedded inside the magnetic roller formed by injection molding to overcome the disadvantage regarding the fact that magnetic rollers are easily damaged by external force. This helps enhance the durability of the magnetic rollers.
  • this embodiment is the same as Embodiment 1.
  • the magnetic flux densities of N21", S21", 01", S31" and N11" are 40mT, 50mT, 15mT, 60mT and 90mT respectively.
  • There are two peak values in the pole S11" which are 60mT and 30mT respectively. Positions of these magnetic poles are not the same and differ greatly from each other. Therefore, number and shape of the magnets together with their positions inside the mold have all to be disposed according to the desired magnetic field distribution diagram as illustrated in Figure 10 .
  • magnets S2c", 0f', S3e", N1a", S1b" and N2d" of different sizes are asymmetrically distributed around the cavity 11.
  • the magnets each has a length identical to that of the magnetic roller (for example, 210mm or 300mm), a width of are 8mm, 15mm, 10mm, 8mm, 25mm and 12mm respectively, and a height of 20mm, 10mm, 10mm, 30mm, 25mm and 20mm respectively.
  • the shape of the cavity 11 can be modified correspondingly to meet the requirements of the wave pattern of the pole S11", so that the magnetic roller formed by injection molding has a cross-section comprising concave-convex portions (as illustrated in Figure 12 ).
  • the present embodiment modifies the shape of the cavity of the mold; this has the advantages of material saving and costs reduction.
  • the characteristics of the method for manufacturing magnetic rollers of the present invention lies in the use of a mold which is mounted with a plurality of magnets to magnetize magnetic rollers simultaneously during injection molding.
  • Magnetic rollers with various magnetic poles can be manufactured by integral molding.
  • Different desired magnetic field distribution diagrams can be attained by arranging magnets of different sizes at different positions of the cavity of the mold, performing different groove-cutting operations or carrying out demagnetization and magnetization processes.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
EP14150471.2A 2014-01-08 2014-01-08 Verfahren zur Herstellung von Magnetrollen und System dafür Withdrawn EP2894519A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP14150471.2A EP2894519A1 (de) 2014-01-08 2014-01-08 Verfahren zur Herstellung von Magnetrollen und System dafür

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP14150471.2A EP2894519A1 (de) 2014-01-08 2014-01-08 Verfahren zur Herstellung von Magnetrollen und System dafür

Publications (1)

Publication Number Publication Date
EP2894519A1 true EP2894519A1 (de) 2015-07-15

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EP14150471.2A Withdrawn EP2894519A1 (de) 2014-01-08 2014-01-08 Verfahren zur Herstellung von Magnetrollen und System dafür

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4640808A (en) * 1981-04-20 1987-02-03 Yamauchi Rubber Industry Co., Ltd. Method for making magnetic rolls
EP0548952A2 (de) * 1991-12-25 1993-06-30 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Herstellungsverfahren für eine Magnetrolle
US6422984B1 (en) * 2000-02-15 2002-07-23 Xerox Corporation Magnetic roll for use in xerographic printing
US20130051865A1 (en) * 2010-06-02 2013-02-28 P.M. Giken Inc. Magnet roller
US20130236216A1 (en) * 2012-03-08 2013-09-12 Takashi Innami Magnet roller, developer bearer, development device, process cartridge, and image forming apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4640808A (en) * 1981-04-20 1987-02-03 Yamauchi Rubber Industry Co., Ltd. Method for making magnetic rolls
EP0548952A2 (de) * 1991-12-25 1993-06-30 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Herstellungsverfahren für eine Magnetrolle
US6422984B1 (en) * 2000-02-15 2002-07-23 Xerox Corporation Magnetic roll for use in xerographic printing
US20130051865A1 (en) * 2010-06-02 2013-02-28 P.M. Giken Inc. Magnet roller
US20130236216A1 (en) * 2012-03-08 2013-09-12 Takashi Innami Magnet roller, developer bearer, development device, process cartridge, and image forming apparatus

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