US3753419A - Electrophotographic liquid developing apparatus - Google Patents

Electrophotographic liquid developing apparatus Download PDF

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Publication number
US3753419A
US3753419A US00155510A US3753419DA US3753419A US 3753419 A US3753419 A US 3753419A US 00155510 A US00155510 A US 00155510A US 3753419D A US3753419D A US 3753419DA US 3753419 A US3753419 A US 3753419A
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United States
Prior art keywords
rollers
insulating sheet
endless belts
disposed
pair
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.)
Expired - Lifetime
Application number
US00155510A
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English (en)
Inventor
O Fukushima
M Sato
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.)
Fujifilm Holdings Corp
Original Assignee
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 US3753419A publication Critical patent/US3753419A/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
    • G03G15/101—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer for wetting the recording material

Definitions

  • ABSTRACT An electrophotographic developing apparatus employing a liquid developer for developing an electrostatic latent image on an insulating sheet, the apparatus comprising (1) at least two pairs of nip rollers, each pair comprising a first roller disposed on one side of the insulating sheet and a second roller disposed adjacent the first roller and on the opposite side of the insulating sheet where the rollers nip and transport the insulating sheet and where successive pairs of rollers are disposed along the direction of movement of the sheet, (2) at least one pair of endless belts suspended between selected nip'rollers at the end portions thereof, the selected rollers being disposed along the direction of movement of the insulating sheet, (3) a plurality of development electrode rollers disposed between each adjacent pair of first rollers and on the same side of the insulating sheet as each of the first rollers and having smaller diameters than the nip rollers with their end portions disposed on the endless belts, and (4) means for supplying the developer liquid onto the surface of the sheet bearing the electrostatic latent image
  • FIG. 1 is a typical example of such conventional devices which is provided with multiple nip rollers and with a means supply a developer liquid.
  • the important features of such device reside in the fact that the many electrode rollers directly contact with the developed surface and that the upper or lower roller in every nip roller pair if forced to rotate.
  • a developing apparatus in which closely packed small diameter rollers are employed which are rotated in the same circumferential velocity as the advancing velocity of the insulating sheet to be developed.
  • the apparatus of 'the present invention is characterized by that it is provided with nip rollers pairs in a number as small as possible, and smaller rollers placed in a close packing between these nip rollers and held apart from the surface on which the latent image is present with a close spacing and driven in the same circumferential velocity as the advancing velocity of the sheet.
  • FIG. 1 is a longitudinal sectional view of a conventional electrophotographic liquid developing appara-
  • FIG. 2 is a longitudinal sectional view of an embodiment according to the present invention.
  • FIGS. 3 and 4 are front views of the nip rollers used in the embodiment shown in FIG. 2.
  • FIG. 5 is a plane view showing the different arrangement of the rollers and endless belts.
  • FIG. 6 is a schematic sectional view of another embodiment according to the present invention.
  • FIG. 7 is a front view of the nip rollers used in the embodiment shown-in FIG. 7.
  • FIG. 8 is a front view of other nip rollers.
  • FIG. 9 is a front view of the developing electrode.
  • FIG. 10 is a schematic sectional view of the other embodiment according to the present invention.
  • l, 2 and 3 are supporting rollers having a smooth surface and a same diameter. They will be referred to as carrier rollers.
  • rollers 4 to 6 designate suppressing or pressure rollers which are freely movable in the vertical direction having the same diameter as the carrier rollers l to 3.
  • the suppressing rollers are on the carrier rollers.
  • Each of these three pairs of rollers forms a nip construction.
  • the diameter of these rollers should be larger than 10 mm and up to about several hundred mm considering a smooth and constant speed rotation without rate fluctuation.
  • the distances between the carrier rollers are much smaller than the length of the sheet to be developed.
  • the rollers 4 to 6 with a metal or an electrically conductive material, they serve as development electrode. If the insulating layer has a very smooth surface on which an electrostatic latent image is formed, the direct contact with such being a problem, a roller covered with a thin insulating material may be employed.
  • rollers 7 and 8 designate two groups of finer rollers, which are finer than 4 to 6, closely arranged held by bearings. They are also movable in the vertical direction and placed on an endless belt 11 with which the rollers frictionally rotate. These finer rollers 7 and 8 will be called development electrode rollers. When the sheet advance horizontally, the rollers may be held by the bearings and on the belt by their own weight, thus they can shift in the vertical direction.
  • the sheet advances horizontally; however, the advancing direction may be inclined relative to the horizon, and in an extreme case, may be vertical, whereby the rollers may be supported by springs having a suitable strength.
  • the thickness of the endless belt 11 is selected slightly greater than that of the sheet to be processed, while its width is arbitrary.
  • the endless belts 11 are suspended between the carrier roller 1-3 at the both ends of the each roller and carried smoothly by rotation of these carrier rollers, and at the same time drive the electrode rollers 7 and 8 friction.
  • the belts may be of any material which can satisfy the above mentioned functions.
  • the belts 11 must be thicker than the insulating sheet and, in order to drive the sheet by friction, the corresponding edge portions of the suppressing rollers are slightly indented as shown in FIG. 4.
  • the suppressing rollers 4 through 6 are forced to come up by the thickness of the sheet.
  • the finer rollers (electrode rollers) 7 and 8 having a uniform diameter, are rotated on the endless belts which are thicker than the sheet. Thus, they are not in direct contact with the surface of the sheet. In other words, the spacing between the finer rollers and the sheet surface is determined by the difference between thickness of the belt which works as spacer and that of the sheet.
  • the width of the sheet 100 should be smaller than the distance between the two endless belts parallelly suspended as shown in FIG. 3.
  • the belts were suspended between the carrier rollers 1, 2 and 3: they may be suspended on the upper rollers 4 to 6. Such structure is shown in FIG. 6, which will be described more in detail later.
  • Drive of the rollers may be accomplished by rotating the rollers l, 2 or 3 in a constant circumferential speed by means of gear or chain.
  • each two adjacent rollers may be connected as shown in FIG. by endless belts whereby the belts serve as spacer as well as driving means.
  • the developer liquid may be fed from above onto the sheet through nozzles 9, again collected in the tray provided beneath the driving station, and then led to a pump through the discharge exit 10.
  • a concentrated developer may be added or the whole volume of the liquid may be replaced by a fresh volume.
  • the endless belt 11 thicker than the sheet 100 (it is preferable as described above) will prevent the direct contact of the electrode rollers with the latent image bearing surface of the sheet, it is not necessary and sufficient conditions for ensuring perfect elimination of such contact.
  • the endless belt is thinner than the sheet, there are cases where the direct contact does not occur when other suitable conditions are satisfied.
  • the electrode rollers on the belt will lie in a single plane between the carrier rollers l to 3.
  • the sheet when the developer liquid is supplied from above onto the surface of the sheet 100, the sheet will show a slight bend between the carrier rollers.
  • the spacing between the electrode roller and the sheet surface will be determined primarily by their thickness difference.
  • the belt 11 bends more than the sheet 100, the spacing will become smaller than the thickness difference and in some cases the sheet surface will come into contact with the electrode rollers. If the sheet bends to a greater extent than the belt 11 does, the spacing will become larger and even a belt thinner than the sheet will cause no direct contact between the sheet and electrode rollers.
  • the nominal spacing thickness difference between the belt and the sheet in the case the extent of bending is equal for the belt and the sheet
  • the spacing will vary due to the variety of the variety of the thickness of the sheets.
  • FIG. 6 An apparatus is shown in FIG. 6 which is free from such dependence; in this embodiment an endless belt is suspended between suppressing rollers instead of carrier rollers.
  • the edge portions of the suppressing rollers around which the endless belts are wound are made indented as shown in FIG. 7.
  • the difference of the radius between the middle and the edge portions of the suppressing rollers is the nominal spacing.
  • FIG. 7 is illustrated the front view of the apparatus shown in FIG. 6 wherein the sheet is nipped between the carrier roller 81 and the suppressing roller 84.
  • the carrier rollers were driven by an outer means, while the suppressing rollers held movable in the vertical direction were rotated frictionally with the carrier rollers.
  • suppressing rollers may be held rigid by bearings and driven by an outer driving means while the carrier rollers are pushed upwardly by the aid of spring and rotated frictionally by the suppressing rollers.
  • the diameters of carrier and suppressing rollers may be different from each other, and may preferably fall between 10 mm to several 10 mmto realize contact area with the sheet enough to insurestable transport of the sheet.
  • the distance between the axes of the adjacent rollers must be smaller than the length of the sheet to be processed measured alongthe advancing direction.
  • rollers In the illustrated examples, only three carrier rollers were provided, but, more or less numbers of rollers may be used.
  • Suitable material for the carrier roller include metal, plastic, rubber, and many other ones.
  • a smooth surface is desirable to avoid smudging of the back surface of the sheet.
  • the effect of the electrode rollers as development electrode will increase as more number of rollers with smaller diameter are used.
  • Too fine rollers will suffer distortion or fall to rotate smoothly whereby they will slip or scrape the developed toner image on the sheet, and a relative movement will take place between the developer liquid and the sheet surface which will cause streaks in the developed toner image.
  • rollers with l to 10 mm diameter are preferred since they will scarcely show too much distortion and will rotate smoothly by the friction with the endless belts.
  • the mutual distance between the electrode rollers would be as small as possible.
  • the adjacent ones may be in light contact with each other as long as smooth rotation is not hindered.
  • Preferred range may be 0.1 to
  • 1.0 mm They may be made of metal preferably with a smooth surface. Suitable examples include polished stainless steel, carbon steel, brass, duralmin, etc.
  • any structure of the roller may be permitted.
  • a thin insulating surface layer may be provided on a conductive core, or a metal roller may be surface treated to form an oxide surface layer thereon. Such surface layer works to prevent the destruction of an electrostatic latent image by leakage when it comes into contact with the latent image.
  • Five electrode rollers are shown in FIG. 6, while the number may be more or less.
  • the latent image bearing surface is not in contact with fine electrode rollers but only with suppressing rollers.
  • the supressing rollers work as development electrode which con tacting with the surface bearing latent image
  • a negligible small residual potential at background area in the latent image will be sharply detected and attract undesirable toner, as has been described in the first part of the disclosure.
  • the contribution from the finer rollers far surpasses that from small number of the suppressing roller and thus such defect is greatly reduced.
  • FIG. 8 is a front view of such apparatus which has substantially a similar configuration as that shown in FIG. 6.
  • Another pair of narrow endless belts I01 and 102 is suspended on the suppressing rollers 104 and grooves 103 are provided to hold the belts near the both ends of the suppressing rollers.
  • the clearance between the sheet surface and the suppressing roller becomeequal to the thickness of the belt 101 minus the depth of the groove 103.
  • the suppressing roller 104 may preferably be made of conductive material to function as development electrode.
  • FIG. 10 illustrates another embodiment of the invention, in which an endless belt 131 is suspended between a pair of carrier rollers.
  • This belt 131 may be wide enough to support the whole width of a sheet to be processed, or similar to 101 or 102 in FIG. 8 provided at the both edges of the carrier rollers.
  • FIG. 3 to FIG. 10 there were not shown means to supply developer, and reservoir for developer which are essentially necessary and only abbreviated.
  • An electrophotographic developing apparatus employing a liquid developer for developing an electrostatic latent image on an insulating sheet, said apparatus comprising;
  • each pair comprising a first roller disposed on one side of said insulating sheet and a second roller disposed adjacent said first roller and on the opposite side of said insulating sheet where the rollers nip and transport said insulating sheet and where successive pairs of rollers are disposed along the direction of movement of said sheet,
  • each said development electrode roller is electrically conductive and has an electrically insulstive overcoating thereon.
  • each of said nip rollers is greater than about 10 millimeters while the development electrode rollers have a diameter range from about 1 millimeter to 10 millimeters.
  • each pair of nip rollers adjacent along the direction of travel of the insulating sheet have suspended therebetween a pair of said endless belts at the respective ends thereof.
  • nominal distance between said development electrode rollers and said insulating sheet being the difference in the thickness of said endless belts and said insulating sheet.
  • Apparatus as in claim 14 where the diameters of the end portions of said first rollers are smaller than the respective middle portions thereof and said endless belts are suspended between said first rollers, the nominal distance between said development electrode rollers and said insulating sheet being the difference in the radii of the middle and end portions of said first rollers whereby contact between said development electrode rollers and said insulating sheet is minimized and said nominal spacing is independent of the thickness of said insulating sheet.
  • Apparatus as in claim 16 where at least one further endless belt is suspended between said second rollers, the width of said further belt being approximately as wide as said insulating sheet.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
US00155510A 1970-06-22 1971-06-22 Electrophotographic liquid developing apparatus Expired - Lifetime US3753419A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45054208A JPS5117050B1 (ja) 1970-06-22 1970-06-22

Publications (1)

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US3753419A true US3753419A (en) 1973-08-21

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US00155510A Expired - Lifetime US3753419A (en) 1970-06-22 1971-06-22 Electrophotographic liquid developing apparatus

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US (1) US3753419A (ja)
JP (1) JPS5117050B1 (ja)
BE (1) BE768788A (ja)
CA (1) CA934540A (ja)
DE (1) DE2130893C3 (ja)
FR (1) FR2099268A5 (ja)
GB (1) GB1337485A (ja)
NL (1) NL7108565A (ja)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3832975A (en) * 1972-02-14 1974-09-03 Rank Xerox Ltd Electro-photographic apparatus
US3862619A (en) * 1972-03-13 1975-01-28 Rank Xerox Ltd Electro-photographic apparatus
US3965861A (en) * 1974-09-04 1976-06-29 Rank Xerox Ltd. Separated roller liquid development
US4142194A (en) * 1976-02-09 1979-02-27 E. I. Du Pont De Nemours And Company Web processor
US4294533A (en) * 1978-03-23 1981-10-13 E. I. Du Pont De Nemours And Company Apparatus for pre-conditioning film
US4963937A (en) * 1989-03-17 1990-10-16 Xerox Corporation Development apparatus
US20080112728A1 (en) * 2004-07-30 2008-05-15 Cormier Steven O Method for producing a metallic core for use in cylinder sleeves for an electrophotographic process

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1819848A (en) * 1927-12-02 1931-08-18 Luther G Simjian Photographic developing apparatus
US3308737A (en) * 1963-06-18 1967-03-14 Fuji Photo Film Co Ltd Device for applying a treating solution to sensitized copying paper
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3448720A (en) * 1967-07-12 1969-06-10 Wood Industries Inc Apparatus for preparing planographic offset printing plates
US3556050A (en) * 1968-06-24 1971-01-19 Eastman Kodak Co Liquid development apparatus
US3592678A (en) * 1968-03-28 1971-07-13 Xerox Corp Liquid donor development with electrophoretic cleaning

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1819848A (en) * 1927-12-02 1931-08-18 Luther G Simjian Photographic developing apparatus
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3308737A (en) * 1963-06-18 1967-03-14 Fuji Photo Film Co Ltd Device for applying a treating solution to sensitized copying paper
US3448720A (en) * 1967-07-12 1969-06-10 Wood Industries Inc Apparatus for preparing planographic offset printing plates
US3592678A (en) * 1968-03-28 1971-07-13 Xerox Corp Liquid donor development with electrophoretic cleaning
US3556050A (en) * 1968-06-24 1971-01-19 Eastman Kodak Co Liquid development apparatus

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3832975A (en) * 1972-02-14 1974-09-03 Rank Xerox Ltd Electro-photographic apparatus
US3862619A (en) * 1972-03-13 1975-01-28 Rank Xerox Ltd Electro-photographic apparatus
US3965861A (en) * 1974-09-04 1976-06-29 Rank Xerox Ltd. Separated roller liquid development
US4142194A (en) * 1976-02-09 1979-02-27 E. I. Du Pont De Nemours And Company Web processor
US4294533A (en) * 1978-03-23 1981-10-13 E. I. Du Pont De Nemours And Company Apparatus for pre-conditioning film
US4963937A (en) * 1989-03-17 1990-10-16 Xerox Corporation Development apparatus
US20080112728A1 (en) * 2004-07-30 2008-05-15 Cormier Steven O Method for producing a metallic core for use in cylinder sleeves for an electrophotographic process

Also Published As

Publication number Publication date
CA934540A (en) 1973-10-02
DE2130893C3 (de) 1979-08-30
NL7108565A (ja) 1971-12-24
BE768788A (fr) 1971-11-03
DE2130893A1 (de) 1971-12-30
DE2130893B2 (de) 1979-01-04
GB1337485A (en) 1973-11-14
FR2099268A5 (ja) 1972-03-10
JPS5117050B1 (ja) 1976-05-29

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