US3834810A - Electrostatic latent image transferring apparatus for use in electrophotography - Google Patents

Electrostatic latent image transferring apparatus for use in electrophotography Download PDF

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Publication number
US3834810A
US3834810A US00416732A US41673273A US3834810A US 3834810 A US3834810 A US 3834810A US 00416732 A US00416732 A US 00416732A US 41673273 A US41673273 A US 41673273A US 3834810 A US3834810 A US 3834810A
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United States
Prior art keywords
conductive
photosensitive drum
photosensitive
feed rollers
layer
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Expired - Lifetime
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US00416732A
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English (en)
Inventor
J Kurokawa
T Watanabe
T Asami
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Ricoh Co Ltd
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Ricoh Co Ltd
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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
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/18—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a charge pattern

Definitions

  • An electrophotographic apparatus for transferring electrostatic latent images comprising a photosensitive drum consisting of a layer of photosensitive material on a conductive body; an insulating roller normally disposed in contact with said photosensitive drum for the purpose of transferring an electrostatic latent image formed on said layer of photosensitive material to an interposable electrostatic transferpaper consisting of a conductive paper support with an image receiving dielectric layer thereon; at least one set of paper feed rollers disposed in front of and one set disposed to the rear of said insulating roller (the rollers disposed on the side of said dielectric layer consisting of an insulating material while the rollers disposed on the side of said paper support consist of a conductive material) for feeding the electrostatic transfer paper in between said insulating roller and photosensitive drum
  • photosensitive drum 1 consists of a photosensitivelayer l1 and a conductive body 12.
  • Conductive roller2' is fortransferring the electrostatic latent image formed on the photosensitive layer 11 to the electrostatic transfer paper '8 which consists of a dielectric layer and a conductive paper support.
  • a low-voltage DC power source of 100- 500V is connected to the roller'2.
  • Two sets of rollers 4 supply the electrostatic transferpaper 8.between the roller ,2 and the photosensitive drum l'for transferring the electrostatic latent image thereto and further sending it to a developing section 7.
  • a corona vdischarger 5 having a high-voltage DC power source 6 of. 6-8KV and an optical system 9 are appropriatelydisposed about .drum 'l.ln -FlG.i2theatransferring section of the apparatus shown in FIG. 1 is shown on-an enlarged scale.
  • the object of the present invention is to make up for the foregoing defects of the prior art and to provide an improved apparatus for transferring electrostatic latent images which comprises a photosensitive layer free of dielectric breakdown and accordingly of permanent durability.
  • the present invention involves an apparatus for transferring electrostatic latent images suited for use in .electrophotography, which comprises a photosensitive .drum consisting of a photosensitive layer on a conductive -body;.an insulating, rather than'conductive, roller normallydisposed in contact with said photosensitive layer for the purpose of transferring an electrostatic latent image formed on said photosensitive layer to an interposable electrostatic transfer paper consisting of a conductive paper support and a dielectric layer; at least one set of paper feed rollers disposed in front of and one set disposed in the rear of said insulating roller (the rollers disposed on the side of said dielectric layer consisting of an insulating material while the rollers disposed on the side of said paper support consist of a conductive material) for feeding the electrostatic transfer paper in between said insulating roller and photosensitive drum; and a low-voltage DC power source having one terminal with the same polarity as that of the electric chargeof the corona discharge to be imparted to the
  • the chassis of the apparatus means a device for supporting the parts necessary for the apparatus, namely, the photosensitive drum, transferring roller, feed rollers, low-voltage DC power source and so on, which may further include the frame, electrifier, optical system, developing device, fixing device, etc.
  • FIG. 1 is a diagrammatic representation of an apparatus for transferring an electrostatic latent image in accordance with the prior art.
  • FIG. 2 is a diagrammatic representation of the transferring section on an enlarged scale of the apparatus shown in FIG 1.
  • FIG. 3 is a diagrammatic representation of an apparatus for transferring electrostatic latent images according to the present invention.
  • FIG. 4 is a curve showing the change of surface potential on the selenium layer in Example 1, and
  • FIG. 5 is a curve showing the change of surface potential on the organic photoconductive layer in Example 2.
  • FIG. 3 is a diagrammatic representation of an apparatus embodying the present invention.
  • the photosensitive drum 1 is insulated relative to the chassis of the apparatus (not shown in the drawing) and this drum is charged with a voltage in the range of l00-500V having the same polarity as that of the electric charge of the corona discharge by means of a lowvoltage DC power source 3a at the time of transferring.
  • the entire transferring roller 2a or at least the surface thereof coming in contact with the photosensitive layer 11 of the photosensitive drum 1 consists of an insulating material such as rubber, resin or the like.
  • roller 2a consists of rubber
  • the closeness of surface contact between the electrostatic transfer paper and photosensitive layer can be furthered.
  • the surface of the roller disposed on the support side of the electrostatic transfer paper 8 consists of a conductive material, such as metal or conductive rubber, and is grounded through the chassis of the apparatus.
  • rollers 4a and 4d on the support side of transfer paper 8 when conductive function as one electrode at the time of image transference to the electrostatic transfer paper and act to impress an external voltage by means of the low-voltage DC power source 30.
  • the rollers 4b and 4d on the side of the dielectric layer are all insulated relative to the chassis of the apparatus, so that they never exert any harmful influence electrically upon the electrostatic transfer paper and the rollers 4a and 4c on the support side.
  • the corona discharger 5 is so devised that, even when the photosensitive layer is in a state of low potential, the discharger is provided with a high-voltage power source 6 having a potential far greater than that of said photosensitive layer, and therefore no influence is exerted upon the corona discharge, thereby permitting proper electrification of the photosensitive layer without hindrance. Further, inasmuch as one of the terminals of the low-voltage DC power source 3a has the same polarity as the polarity of the electrical charge of the corona discharge, such a power source can be taken out of a part of the high-voltage DC power source used for the corona discharge. In this case, inasmuch as the support side of the electrostatic transfer paper is always grounded by means of the conductive feed rollers 4a and 4c, no influence will be exerted thereby at the time of development and a satisfactory image will be obtained.
  • the photosensitive drum 1 employed may consist of a metal drum having a diameter of 70 mm provided with a 25 1:. thick photosensitive layer of selenium.
  • this selenium layer of the drum is imparted with +300V potential by a lowvoltage DC power source 30 and a corona discharge of +7.0 KV is effected by rotating the drum at a velocity of 40 rpm, the apparent surface potential of thephotosensitive drum becomes 1000V as-shown in FIG. 4.
  • the selenium layer is electrified by corona discharge to the extent of a potential of only 700V in effect, and even when it comes in direct contact with an insulating transferring roller 2a, the electric field acting on the selenium layer is trifling, so that the durability of the selenium drum is remarkably improved.
  • EXAMPLE 2 ent surface potential on the organic photoconductive drum on this occasion will be 800V as shown in FIG. 5;
  • the residual potential of this organic photoconductor at the time of light decay is greater than that of selenium, application of a high external electric field at the time of image transference is attended with the transfer of the electric charge of the non-electrostatic latent image area and tends to give rise to a stained ground on the electrostatic transfer paper, but in the case of the present apparatus, application of a low potential of --200V can bring on a satisfactory result.
  • the transferred potential on the electrostatic transfer paper will be 90V and (W for the electrostatic latent image area and the non-electrostatic latent image area, respectively.
  • An electrostatic latent image transferring apparatus for use in electrophotography, comprising: a photosensitive drum consisting of a photosensitive layer and a conductive body; an insulating roller disposed in contact with said photosensitive layer for transferring an electrostatic latent image formed by corona discharge and illumination on said photosensitive layer to an interposable electrostatic transfer paper consisting of a conductive paper support with an image receiving dielectric layer thereon; at least one set of paper feed rollers disposed in front of and one set disposed to the rear of said insulating roller, the feed rollers disposed on the side of said dielectric layer having an insulating surface and at least one of the feed rollers disposed on the side of said paper support having a conductive surface, for feeding the electrostatic transfer paper in between said insulating rollers and said photosensitive drum; and a low-voltage DC power source having one terminal with the same polarity as that of the electric charge of the corona discharge applied to the photosensitive layer and electrically connected with said conductive body of the photosensitive drum and the other terminal having
  • a transferring apparatus according to claim 1, wherein said photosensitive layer of the photosensitive drum consists of selenium.
  • a transferring apparatus according to claim 1, wherein said photosensitive layer of the photosensitive drum consists of poly-N-vinylcarbozole.
  • a transferring apparatus according to claim 1, wherein the voltage of said low-voltage DC power source is in the range of IOU-500V.
  • a transferring apparatus according to claim 1, wherein both of said feed rollers on the side of said paper support are conductive.
  • a transferring apparatus according to claim 1, wherein the surfaces of said insulating feed rollers comprise rubber.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
US00416732A 1972-11-21 1973-11-19 Electrostatic latent image transferring apparatus for use in electrophotography Expired - Lifetime US3834810A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47116212A JPS4975142A (enrdf_load_stackoverflow) 1972-11-21 1972-11-21

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US3834810A true US3834810A (en) 1974-09-10

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US (1) US3834810A (enrdf_load_stackoverflow)
JP (1) JPS4975142A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4045135A (en) * 1973-09-07 1977-08-30 Minolta Camera Kabushiki Kaisha Electrophotographic copying apparatus with retractable image transfer roller means

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3115814A (en) * 1955-12-06 1963-12-31 Edward K Kaprelian Offset electrophotography
US3147679A (en) * 1961-12-18 1964-09-08 Ibm Electrostatic image transfer processes and apparatus therefor
US3666458A (en) * 1968-11-25 1972-05-30 Kalle Ag Process for transferring electrostatic charge images

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3115814A (en) * 1955-12-06 1963-12-31 Edward K Kaprelian Offset electrophotography
US3147679A (en) * 1961-12-18 1964-09-08 Ibm Electrostatic image transfer processes and apparatus therefor
US3666458A (en) * 1968-11-25 1972-05-30 Kalle Ag Process for transferring electrostatic charge images

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4045135A (en) * 1973-09-07 1977-08-30 Minolta Camera Kabushiki Kaisha Electrophotographic copying apparatus with retractable image transfer roller means

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JPS4975142A (enrdf_load_stackoverflow) 1974-07-19

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