US3123501A - Electrophotographic developing apparatus - Google Patents

Electrophotographic developing apparatus Download PDF

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Publication number
US3123501A
US3123501A US3123501DA US3123501A US 3123501 A US3123501 A US 3123501A US 3123501D A US3123501D A US 3123501DA US 3123501 A US3123501 A US 3123501A
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Prior art keywords
electrophotographic
developer
slope
trough
electrophotographic material
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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
    • G03G15/082—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer for immersion

Definitions

  • the developer normally consists of a mixture of what is known as a carrier and a toner.
  • the carrier glass balls of a diameter of a few hundred microns or iron filings may be used.
  • the toners normally consist of a resin powder of a diameter of a few microns.
  • mechanical devices have been used which scatter the developer on the electrophotographic layer; this has the disadvantage that uniform distribution of the toner is very difiicult with such devices unless the material is scattered very thickly to start with. In such case, however, a very large quantity of the toner must be removed and afterwards collected which results in an undesirable whirling about of the toner and, hence, loss thereof coupled with dirtying of the vicinity of the developing apparatus.
  • Electrophotographic developers have been placed in rotating drums having an aperture corresponding to the size of the electrophotographic material.
  • the electrophotographic material is then stretched over this aperture by means of a clamping frame and the container is simultaneously tightly closed.
  • An arrangement of this sort is relatively time-consuming in operation, as the clamping of the sheet is somewhat complicated and, moreover, must be done in a dark room.
  • the development of electrophotographic material having a latent electrostatic image has also been attempted by a process in which the electrophotographic material is caused to pass through an accumulation of developer powder. In this case, however, the movement of the electrophotographic material becomes very diificult and requires special guide members. It is therefore imperative that the electrophotographic material be larger than the master being copied if these guide members are to be used Without damage to the image.
  • a developing device for latent electrostatic images which includes a trough with smooth side walls, an inlet slope with an angle of about 30, an adjoining curved section with a radius that is at least 500 times the thickness of the electrophotographic material being developed, an adjoining upward slope with an angle of approximately 45, which is preferably interrupted by a shoulder preferably at about the same height as the inlet, an upward discharge slope of about 60 adjoining the shoulder, and, preferably, a tank in which the developing device is disposed.
  • FIG. 1 shows a cross section of one embodiment of the device of the present invention.
  • FIG. 2 shows a perspective view of the same embodiment of the device.
  • the developing device consists of a trough the curved surface of which has a radius 1 that is at least approximately 500 times the thickness of the cut electrophotographic material to be developed. It has been found that the radius of this curve must bear a specific relationship to the electrophotographic material being processed so that, under the weight of the developer, the sheet fits the radius of the "ice curve. With electrophotographic material of the usual thickness of 0.1 to 0.15 min, a radius of -100 mm. will be necessary.
  • the inlet 2 to the trough should slope at about 30 to the horizontal and the discharge 3 at about 45. At about the same height as the inlet there is advantageously a shoulder 4 which interrupts the discharge. On the other side of the shoulder the upward discharge slope 5 is advantageously at an angle of about 60 to the horizontal.
  • the electrophotographic material e.g., an electrophotographic printing plate which has an electrophotographic coating on an aluminum support
  • the electrophotographic material is placed With its leading edge on the inlet slope of the trough, which is about one third to half filled with developer, and then the material is pushed under the developer. Because of its rigidity, the electrophotographic material fits the radius of curvature of the trough so well that practically the entire quantity of developer is on top of the electrophotographic material and runs or slides over the coated side. Thus, the entire coating comes into contact with the toner very uniformly without any whirling about of the developer and the latent image becomes visible.
  • the shoulder 4 it has proved particularly advantageous for the shoulder 4 to be incorporated in the discharge; this prevents developer being pushed out of the trough by the electro photographic material or by the mounting holes fitted therein. Such portions of developer then collect on the shoulder and can be easily tipped back into the developing device.
  • the device When the electrophotographic material has been pushed through the developing device far enough to project over the discharge end of the trough it is grasped by the other hand of the operator and pulled through the developing device.
  • the device is set up in a tray or tank 6 so that any additional particles of toner that may fall from the sheet will be collected.
  • a lid 7 serves as cover for the device when it is not in use.
  • the device of the invention enables electrophotographic material, particularly in cut sheets, to be developed in a very simple manner to produce images having excellent uniformity.
  • a device for developing latent electrophotographic images comprising a trough having a downward inlet slope of an angle of about 30", an adjoining curved portion having a radius of at least about 500 times the thickness of electrophotographic material to be developed, an adjoining upward discharge slope having an angle of about 45, and an upward outlet slope having an angle of about 60.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
US3123501D 1961-04-22 Electrophotographic developing apparatus Expired - Lifetime US3123501A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR859581A FR1291105A (fr) 1961-04-22 1961-04-22 Dispositif de développement pour électrophotographie

Publications (1)

Publication Number Publication Date
US3123501A true US3123501A (en) 1964-03-03

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Application Number Title Priority Date Filing Date
US3123501D Expired - Lifetime US3123501A (en) 1961-04-22 Electrophotographic developing apparatus

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US (1) US3123501A (en:Method)
FR (1) FR1291105A (en:Method)
IT (1) IT649607A (en:Method)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR446215A (fr) * 1912-06-29 1912-11-29 Carl Pletsch Bac pour bains de zingage renfermant de l'aluminium, avec dispositif produisant le déplacement mécanique des toles à zinguer
US2508886A (en) * 1947-11-01 1950-05-23 John F Morse Photographic developing tray holder
FR1114965A (fr) * 1954-10-29 1956-04-18 Buerogerate A G Dispositif pour le développement des papiers sensibles
FR1196529A (fr) * 1957-05-31 1959-11-24 Kalle & Co Ag Procédé et appareil pour le développement des images électrostatiques
US2972331A (en) * 1956-06-29 1961-02-21 Zindler Lumoprint Kg Device for developing a latent electrostatic image
US3021817A (en) * 1956-08-29 1962-02-20 Zindler Lumoprint Kg Copying of documents

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR446215A (fr) * 1912-06-29 1912-11-29 Carl Pletsch Bac pour bains de zingage renfermant de l'aluminium, avec dispositif produisant le déplacement mécanique des toles à zinguer
US2508886A (en) * 1947-11-01 1950-05-23 John F Morse Photographic developing tray holder
FR1114965A (fr) * 1954-10-29 1956-04-18 Buerogerate A G Dispositif pour le développement des papiers sensibles
US2972331A (en) * 1956-06-29 1961-02-21 Zindler Lumoprint Kg Device for developing a latent electrostatic image
US3021817A (en) * 1956-08-29 1962-02-20 Zindler Lumoprint Kg Copying of documents
FR1196529A (fr) * 1957-05-31 1959-11-24 Kalle & Co Ag Procédé et appareil pour le développement des images électrostatiques

Also Published As

Publication number Publication date
IT649607A (en:Method)
FR1291105A (fr) 1962-04-20

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