US3707943A - Electrophotographic device - Google Patents

Electrophotographic device Download PDF

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Publication number
US3707943A
US3707943A US00104978A US3707943DA US3707943A US 3707943 A US3707943 A US 3707943A US 00104978 A US00104978 A US 00104978A US 3707943D A US3707943D A US 3707943DA US 3707943 A US3707943 A US 3707943A
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United States
Prior art keywords
sheet
portions
electrode
developing
potential
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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.)
Expired - Lifetime
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US00104978A
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English (en)
Inventor
S Matsumoto
Y Tamai
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Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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Filing date
Publication date
Application filed by Fuji Photo Film Co Ltd filed Critical Fuji Photo Film Co Ltd
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Publication of US3707943A publication Critical patent/US3707943A/en
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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
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer

Definitions

  • An electrophotographw device wh1ch comprises a de- Jan. 9, Japan the entry of a sheet shaped material provided in the path of the sheet-shaped insu- [52] US. Cl ..118/7, 117/37 LE, ll8/DIG. 23, lating material to a development station including a 118/637 355/10 developing electrode divided into smaller portions in [51] Il lt. Cl ..B05c 11/00 the direction perpendicular to the direction in which [58] Field of Search ..118/7, DIG.
  • the sheet is advanced, closing and opening circuits for 117/37 LX; 355/10 14 application of electric potential to the portions of the 0 developing electrode, and a delay circuit which [56] Rekrences C'ted receives the signal from the detector and makes the UNITED STATES PATENTS circuits close so as to apply electric potential only to the port1ons of the electrode confronting the sheet- 3,137,306 6/1964 Cunha et al. ..134/46 shaped insulating material.
  • FIG. 1 is a schematic side sectional view of the ordinary reversal liquid developing device for electrophotography
  • FIG. 2, FIG. 4 and FIG. 5 are schematic diagrams of the important parts of the device for working the present invention and FIG. 3 is a schematic diagram illustrating one embodiment of the control device designed to permit the electric field to act only on a sheet-shaped insulating material.
  • This invention relates to an electrophotographic device for causing more developing particles to be deposited effectively on portions of an insulating material having less electric charge.
  • the toner is deposited on the surface of insulating material in accordance with the electrostatic latent image formed thereon.
  • the insulating material containing the electrostatic latent image is not a long continuous roll but is a comparatively small sheet in shape and such sheet-shaped insulating material is fed intermittently to the developing device to be developed, there can be occasions on which there is no sheet close to the developing electrode.
  • the electric potential being applied to the developing electrode causes the toner to adhere wastefully to the interior of the developing device and toner is extremely wasted. As a consequence, the toner is wasted heavily and the interior of device is smeared.
  • FIG. 1 illustrates one example of the device for working such ordinary reversal developing method.
  • the container 1 is filled with what has toner dispersed in an insulating liquid (hereinafter referred to an liquid developing agent) 10, with a developing electrode 4 and an endless carrier belt 5 disposed in the state immersed in saidliquid developing agent.
  • the developing electrode 4 and the carrier belt 5 are both electroconductive and the electric potential is applied by means of the power source 8 so as to produce an electric field between them.
  • the carrier belt 5 is revolved in the direction indicated by the arrow mark 6 by means of rollers 7 and 7' so as to fulfil the function of carrying the sheet 2 containing therein an electrostatic latent image 3 into the gap 11 between the developing electrode 4 and the carrier belt 5 and then carrying out the sheet along the guide 9.
  • the application of electric potential must be continued until the sheet 2 has departed completely from the opening 11 and, therefore, the electric field develops at the portion of opening 11 in which the sheet 2 is partially absent so far as any portion of the sheet 3 is still in existence in the gap 11.
  • the toner is continuously deposited on the carrier belt.
  • the present invention relates to an electrophotographic device which has a solution to such problem.
  • FIG. 2 illustrates one example of the reversal developing device for electrophotography according to the present invention.
  • the sheet 2 to be developed is forwarded by rollers 30 and 30' along the guide 9 into the gap 11.
  • the means 12 and 12' which serve to detect the entry of the sheet 2 sense the forward end position of the sheet.
  • the detecting means 12 and 12 are, for example, of such principle that infrared ray is transmitted from the means 12 and received (or sensed) by the means 12' and the entry of the sheet can be detected by the fact that the sheet 2 intercepts the infrared ray and consequently prevents it from reaching the infrared ray detecting device 12'.
  • the signal issued upon detection of the forward end of sheet causes electric potential to be applied to the developing electrode, with due time allowance given to the delay which occurs before the sheet 2 arrives at the gap 11.
  • the developing electrode 14 is divided into smaller portions in the direction perpendicular to the direction in which the sheet is advanced. As the sheet 2 enters the gap 11, one of the switches 15 is closed on the division of electrode existing at the leftmost position in the diagram to initiate application of electric potential thereby. As the carrier belt 5 advances the sheet further along the gap 11, the remaining switches of the divided developing electrode are closed one after another in the direction toward right synchronously with the conveying speed of the endless belt 5 to provide gradually extending application of electric potential. In this manner, the electrostatic latent image formed on the sheet 2 is developed. In the device shown in FIG.
  • both liquid developing agent and container are identical with those shown in FIG. 1 and are omitted from the diagram.
  • the tall end thereof is detected by the detecting means 12 and 12' and, when the tail end of the sheet has completely passed the leftmost division of developing electrode with a given delay, the switches 15 are opened in sequence to stop the application of electric potential to the developing electrode gradually.
  • the switch 15 are gradually opened synchronously with the conveying speed. Consequently, the electric potential is removed at portions of gap 11 from which the sheet has been removed, whereby the wasteful consumption of toner within the liquid developing agent can be prevented.
  • this device there may be incorporated a circuit which permits the application of electric potential to be retained for a fixed length of time as from the time of detection of the passage of the forward end of sheet where the conveying speed of sheet is kept constant.
  • the duration of the application of electric potential to the electrode is slightly shorter than the time required for the sheet to pass under the electrode completely, the developing speed is, as a matter of course, decreased though to a small extent. Although this is not desirable, it is still much better than when the duration is excessively long.
  • FIG. 3 illustrates one example of the delay device for controlling the switch which functions to start and stop the application of electric potential to the developing electrode. It functions to cause the output from the sheet detecting device 12 to be amplified by means of the amplifier l6 and to close the switch 18 by means of the relay when the sheet remains at the position of detection.
  • Numeral l7 denotes a means for exciting the magnetic recording ring head 19 with an AC power source of about 1,000 c/s.
  • the magnetic recording head 19 is excited by the closure of the switch 18. Consequently, the magnetic recording tape 22 is magnetized and the signal is recorded thereon.
  • the tape moves as indicated by the arrow mark 23. This movement corresponds to the motion of the sheet.
  • the portion at which the signal has been recorded moves toward right in the diagram and reaches the portion directly below the group of signal reading heads 25.
  • the fact that the portion of the tape at which the signal has been recorded reaches the reading head at the leftmost position corresponds to the fact that the sheet just reaches the left end of the gap 11 in the diagram of FIG. 2.
  • the portion of recorded signal moves to the right and, at
  • the switch 18 is opened and the recording head 10 is deprived of excitation.
  • the signal recorded on the magnetic tape 22 is no longer in existence, because the magnetic tape has already been treated with a permanent magnet 20 to erase the signal.
  • the portion of the tape from which the signal has been erased reaches the group of reading heads 25 and reading of signal no longer occurs. Consequently, the switches 15 in the diagram of FIG. 2 are opened so as to stop the application of electric potential to the developing electrode one after another from the left.
  • electric potential is applied only at portions of the gap 11 illustrated in FIG. 2 where the sheet 2 exists. Since no electric field exists at portions where the sheet is no longer in existence, waste of toner can be prevented.
  • FIG. 4 illustrates an example wherein a multiplicity of electroconductive rollers 26 of a small diameter employed to function as developing electrodes are moved by a motor not shown in the diagram so as to smoothen the passage of sheet along the gap.
  • FIG. 5 is an example of the device adapted to permit the electric potential being applied to the divided developing electrode to be varied so as to prevent possible adverse effect due to such phenomenon as dark decay of electrostatic image on the sheet. It is generally desirable to keep the potential at a higher magnitude on the side the sheet enters the device and at a lower magnitude on the side the sheet departs from the device.
  • Numeral 27 denotes a group of resistors which serves to divide the electric potential of the power source 28. By means of this group of resisters 27, the electric potential being applied to the divided developing electrode can be varied.
  • the description made to this point has covered a reversal developing device.
  • the device of the present invention can also be utilized for permitting the toner to be deposited substantially uniformly throughout the entire surface of a sheet containing no electrostatic latent image. In other words, it can be used as a means for supplying the toner without any wasteful consumption of toner or smearing the device interior. This means that it can be used for the preparation of toner sheet.
  • An electrophotographic device which comprises a detector which detects the entry of a sheet-shaped material provided in the path of the sheet-shaped insulating material to a development station including a developing electrode divided into smaller portions in the direction perpendicular to the direction in which the sheet is advanced, closing and opening circuits for application of electric potential to the portions of the developing electrode, and a delay circuit which receives the signal from said detector and makes s'aid circuits close so as to apply electric potential only to the portions of the electrode confronting the sheetshaped insulating material.
  • An electrophotographic device as claimed in claim 5, wherein said delay circuit comprises a magnetic recording tape carried synchronously with the transportation of the sheet, a magnetic recording head confrontingsa'id recording tape and excited by the signal from the detector, and plurality of heads which read the-signal on the tape and put out the signal to close detecting means for sensing the presence of said sheet along its path of movement; at least one source of potential; and
  • said delay means includes a movable storage medium, the output from said detecting means being recorded thereon
  • said actuating means includes (1) a plurality of switching means connected between said potential source and said plurality of development electrode portions respectively and (2) a plurality of sensing means successively disposed along a portion of said movable storage medium and respectively connected to said plurality of switching means, the first of said sensing means being disposed a predetermined distance from where the output from said detecting means is recorded on said movable storage medium and distance between said sensing means corresponding to the distance between said development electrode portions.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
  • Developing For Electrophotography (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
US00104978A 1970-01-09 1971-01-08 Electrophotographic device Expired - Lifetime US3707943A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45002820A JPS527348B1 (de) 1970-01-09 1970-01-09

Publications (1)

Publication Number Publication Date
US3707943A true US3707943A (en) 1973-01-02

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ID=11540033

Family Applications (1)

Application Number Title Priority Date Filing Date
US00104978A Expired - Lifetime US3707943A (en) 1970-01-09 1971-01-08 Electrophotographic device

Country Status (8)

Country Link
US (1) US3707943A (de)
JP (1) JPS527348B1 (de)
BE (1) BE761331A (de)
CA (1) CA934539A (de)
DE (1) DE2100370C3 (de)
FR (1) FR2075331A5 (de)
GB (1) GB1336024A (de)
NL (1) NL7100157A (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3804510A (en) * 1970-02-04 1974-04-16 Fuji Photo Film Co Ltd Imaging developing system
US3817212A (en) * 1972-01-10 1974-06-18 Xerox Corp Electrostatographic liquid development apparatus
US3951653A (en) * 1973-08-30 1976-04-20 Rank Xerox Ltd. Method of preventing toner build-up on electrodes during liquid development
US3970043A (en) * 1973-06-18 1976-07-20 Xerox Corporation Electrophotographic device for liquid development
FR2301850A1 (fr) * 1975-02-20 1976-09-17 Hoechst Ag Procede et dispositif pou
US4021111A (en) * 1974-06-10 1977-05-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
US4037952A (en) * 1973-08-30 1977-07-26 Rank Xerox Ltd. Apparatus for liquid development of cut sheet electrostatographic copies
US4045217A (en) * 1974-12-24 1977-08-30 Ricoh Company, Ltd. Developing process for electrophotography
US4052127A (en) * 1973-01-24 1977-10-04 Ricoh Co., Ltd. Developing system
US4141643A (en) * 1974-09-13 1979-02-27 Ricoh Company, Ltd. Developing electrode arrangement for electrophotographic apparatus
US4148274A (en) * 1974-10-15 1979-04-10 Agfa-Gevaert N.V. Processing apparatus
USRE31371E (en) * 1973-01-24 1983-09-06 Ricoh Co., Ltd. Developing system
USRE31707E (en) * 1974-05-10 1984-10-16 Ricoh Company, Ltd. Method and apparatus for electrically biasing developing electrode of electrophotographic device
US4558941A (en) * 1983-03-31 1985-12-17 Takefumi Nosaki Developing apparatus
US6029572A (en) * 1995-06-30 2000-02-29 Rodi; Anton Sheet conveying system in a digital printing press

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3137306A (en) * 1963-11-01 1964-06-16 Fairchild Camera Instr Co Pre-wetter
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3345925A (en) * 1963-01-03 1967-10-10 Scm Corp Electrostatic printing and developing apparatus
US3415223A (en) * 1967-04-24 1968-12-10 Pitney Bowes Inc Development apparatus for electrostatic copiers
US3441345A (en) * 1963-05-20 1969-04-29 Addressograph Multigraph Photocopying
US3474019A (en) * 1965-03-19 1969-10-21 Xerox Corp Photoelectrophoretic imaging method including contacting the imaging suspension with a large surface of a flexible electrode
US3547076A (en) * 1967-03-23 1970-12-15 Sherwin Williams Co Apparatus for increasing the contrast in liquid immersion developing of electrostatic image
US3577259A (en) * 1968-09-19 1971-05-04 Xerox Corp Liquid development of electrostatic latent images utilizing a tonerfree zone

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3345925A (en) * 1963-01-03 1967-10-10 Scm Corp Electrostatic printing and developing apparatus
US3441345A (en) * 1963-05-20 1969-04-29 Addressograph Multigraph Photocopying
US3137306A (en) * 1963-11-01 1964-06-16 Fairchild Camera Instr Co Pre-wetter
US3474019A (en) * 1965-03-19 1969-10-21 Xerox Corp Photoelectrophoretic imaging method including contacting the imaging suspension with a large surface of a flexible electrode
US3547076A (en) * 1967-03-23 1970-12-15 Sherwin Williams Co Apparatus for increasing the contrast in liquid immersion developing of electrostatic image
US3415223A (en) * 1967-04-24 1968-12-10 Pitney Bowes Inc Development apparatus for electrostatic copiers
US3577259A (en) * 1968-09-19 1971-05-04 Xerox Corp Liquid development of electrostatic latent images utilizing a tonerfree zone

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3804510A (en) * 1970-02-04 1974-04-16 Fuji Photo Film Co Ltd Imaging developing system
US3817212A (en) * 1972-01-10 1974-06-18 Xerox Corp Electrostatographic liquid development apparatus
USRE31371E (en) * 1973-01-24 1983-09-06 Ricoh Co., Ltd. Developing system
US4052127A (en) * 1973-01-24 1977-10-04 Ricoh Co., Ltd. Developing system
US3970043A (en) * 1973-06-18 1976-07-20 Xerox Corporation Electrophotographic device for liquid development
US3951653A (en) * 1973-08-30 1976-04-20 Rank Xerox Ltd. Method of preventing toner build-up on electrodes during liquid development
US4037952A (en) * 1973-08-30 1977-07-26 Rank Xerox Ltd. Apparatus for liquid development of cut sheet electrostatographic copies
USRE31707E (en) * 1974-05-10 1984-10-16 Ricoh Company, Ltd. Method and apparatus for electrically biasing developing electrode of electrophotographic device
US4021111A (en) * 1974-06-10 1977-05-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
USRE30535E (en) * 1974-06-10 1981-03-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
US4141643A (en) * 1974-09-13 1979-02-27 Ricoh Company, Ltd. Developing electrode arrangement for electrophotographic apparatus
US4148274A (en) * 1974-10-15 1979-04-10 Agfa-Gevaert N.V. Processing apparatus
US4045217A (en) * 1974-12-24 1977-08-30 Ricoh Company, Ltd. Developing process for electrophotography
FR2301850A1 (fr) * 1975-02-20 1976-09-17 Hoechst Ag Procede et dispositif pou
US4558941A (en) * 1983-03-31 1985-12-17 Takefumi Nosaki Developing apparatus
US6029572A (en) * 1995-06-30 2000-02-29 Rodi; Anton Sheet conveying system in a digital printing press

Also Published As

Publication number Publication date
FR2075331A5 (de) 1971-10-08
GB1336024A (en) 1973-11-07
DE2100370B2 (de) 1974-07-18
JPS527348B1 (de) 1977-03-01
NL7100157A (de) 1971-07-13
DE2100370A1 (de) 1971-07-22
DE2100370C3 (de) 1975-03-06
BE761331A (fr) 1971-06-16
CA934539A (en) 1973-10-02

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