US3392707A - Apparatus for developing latent electrostatic images - Google Patents

Apparatus for developing latent electrostatic images Download PDF

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Publication number
US3392707A
US3392707A US583918A US58391866A US3392707A US 3392707 A US3392707 A US 3392707A US 583918 A US583918 A US 583918A US 58391866 A US58391866 A US 58391866A US 3392707 A US3392707 A US 3392707A
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Prior art keywords
developer
liquid
nozzle
latent electrostatic
image
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Expired - Lifetime
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US583918A
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English (en)
Inventor
Marx Gerhard
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Azoplate Corp
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Azoplate Corp
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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

  • FIGS 6b 7 INVENTOR GERHARD MARX BY W M ATTORN United States PatCQ --3,392,707- APPARATUS FOR DEVELOPING LATENT ELECTROSTATIC *IMAGES Gerhard Marx, Wiesbaden-Kastel, Germany, assignor, by mesne assignments, to Azoplate Corporation, Murray Hill, NJ.
  • This invention relates to an apparatus for developing latent electrostatic images using a dispersion developer which comprises at least one elongated nozzle means for producing developer spray, the nozzle means being mounted within a slot in one of two opposed hollow bar means having a space between them, each bar means having at least one longitudinal slot and the slots facing each other, and means for establishing a negative pressure within the bar means.
  • This invention relates to an apparatus for rendering latent electrostatic images visible by contacting an electrophotographic material carrying such an image with a so-called dispersion developer.
  • Dispersion developers as used in electrophotography the liquid developers and constitute a dispersion of solid toner particles in a liquid medium which has a high specific resistance and a low dielectric constant.
  • a developer of this kind By contacting a developer of this kind with a surface electrostatically charged image-wise, the toner particles are attracted by the surface in accordance with the charge image, while the highly resistant liquid flows off.
  • a visible image is formed and, depending upon the nature of the charge on the surface of the latent electrostatic image to be developed and the nature of the charge on the dispersed particles, either positive or negative prints of the original are obtained.
  • Spraying devices could be made suitable, but an undesirdraining of the liquid from the higher to the 3,392,707 Patented July 16, 1968 "Ice able effect occurswhenan "attempt is made to develop a vertical image-carrier sheet with perpendicular or slightly inclined slotted nozzle or nozzles having a series of holes.
  • the lower areas of the image are more strongly developed thanthe upper ones and, in addition, lettering shows blurring in the direction of movement. This is due to the lower part of the image.
  • the present invention provides an apparatus for developing latent electrostatic images by means of a dispersion developer, in which apparatus means are provided for continuously supplying developer in spray form and for continuously removing unapplied developer and any excess of applied developer, and means including at least one elongated nozzle for producing developer spray, the nozzle or nozzles being spaced within a slot of one of two opposed hollow section bars each having at least one longitudinal slot with the slots facing one another.
  • the bars are spaced for passage of the material to be developed between them and the arrangement is such that, by establishing a negative pressure within both hollow bars, unapplied developer can be removed through the slot or slots in the bar not containing the nozzle and any excess of applied developer can be removed through the slot or slots in the bar containing the nozzle.
  • spray form is meant any suitable curtain of liquid, as referred to more particularly below.
  • una-pplied developer is meant developer which, during continuous delivery, does not strike material to be developed.
  • excess of applied developer is meant developer which strikes material to be developed and is deflected back therefrom.
  • Elongated nozzles may contain, as nozzle apertures, :a slot or slots or a series of holes.
  • the apparatus may be adapted for passage of the material to be developed in a vertical position.
  • the nozble aperture may be reduced in cross-section in the direction from the top downwardly.
  • means may be provided for collecting any residual liquid from the lower edge of the material being developed.
  • FIGURE 1 is a general perspective view
  • FIGURE 2 is a cross-section through a simple constructional form of developing device
  • FIGURES 3, 4, and 5 are cross-sections through additional constructional forms of this device.
  • FIGURE 1 the hollow section bars 1 and 2 are shown without any top covering in order to reveal the internal arrangement.
  • These hollow section bars instead of being of square section as shown in FIGURE 1, may have other desired crosssection and may, for example, be polygonal, circular or oval. The choice of section will be made according to the particular requirements.
  • Materials from which the hollow section bars are made must be solvent-proof in order to resist the dispersing agents and so as not to become distorted. Accordingly, practically all metals and also a large number of plastics may be employed for producing the hollow section bars.
  • the longitudinal slots 3 and 4 in the hollow section bars preferably are made by machining. Their width depends on various factors, primarily on whether there are one or more slots in each bar and also on what quantities of liquid are to be delivered per unit of width. Furthermore, the flow behavior of the developer liquid must be considered. With more viscous liquids, wider slots must be provided than in the case of those having a lower viscosity. In addition, when the slots are made, consideration must be given to the suction power with which the pump operates. If it produces only a weak negative pressure, the slots must be narrower than in the case of a stronger negative pressure. Moreover, in the case of the hollow section bar in which the spray nozzle is housed (see below), the width of the nozzle at the outer edge must be taken into account. Generally, it will be found that, with slot widths of 1 mm. to 10 mm., and when the other conditions are suitably selected, successful operation of the apparatus according to the invention always can be achieved.
  • both hollow section bars it is not necessary for both hollow section bars to have the same number of slots or for these always to be exactly opposite one another.
  • the hollow section bar 2 receiving unapplied liquid with two slots which are disposed opposite the spray nozzle and to the right and left of the line of outlet of the liquid, as shown in the case of the slots 3a and 3b in FIGURE 4.
  • the hollow section bars 1 and 2 are disposed opposite one another at a small distance apart, so that a gap 5 (FIGURE 2) is formed between them.
  • This gap must be at least of such a width that the thickest image-carrier sheet employed can pass through it without difficulty. With a width of about 0.2 mm., this normally will be the case.
  • a width of about 0.2 mm. this normally will be the case.
  • the nozzles from which the developer liquid is forced may have various forms. As already stated, they may be constructed as broad slotted nozzles or as nozzles with a series of holes. Broad slotted nozzles 6 may consist, for example, of two separate metal jaws pressing one on the other and whose upper inner surfaces, which form the side boundaries of the passage 7 from which the liquid issues, are provided with as high a degree of surface finish as possible. In this constructional form, the passa-ge within the nozzle should be of such length and width that a substantially laminar flow develops therein. The spray jet issuing from the broad slotted nozzle then forms a completely even curtain of liquid with which particularly good prints are obtained.
  • the gap widths in slotted nozzles of this kind should be between 0.1 and 2.0 mm., preferably between 0.2 and 1 mm.
  • Simpler to produce are constructional forms of broad slotted nozzles as shown in FIGURES 4 and 5.
  • two ducts or passages 8 are formed leading into the outlet gap in each case.
  • This form preferably is used with low throughputs of liquid.
  • -Low throughputs of liquid are those in which about 0.1-0.3 liter/min. of liquid is delivered per centimeter of nozzle width. Liquids delivered in this way would not normally be described as being sprayed, but in the present case this term conveniently may be used to include this kind of delivery.
  • Nozzles with a series of holes also may be used. These may consist, for example, of a tube with one or more straight rows of holes. A separate small spray jet issues from each hole. When only one row of spray holes is used, there may be a noticeable effect as regards longitudinal streaking of the print. In order to prevent this undesirable effect when nozzles with a series of holes are employed, it is convenient to arrange at least two rows of holes parallel to one another. The holes in one row are then staggered with respect to those in the adjacent row. Prints of high quality then can be also produced with nozzles having a series of holes. The diameters of the holes in the tubes may be about 0.2-2 mm.
  • FIGURE 5 An example of an arrangement with two spray nozzles 6a and 6b is shown in FIGURE 5.
  • the apparatus of the invention When the apparatus of the invention is arranged vertically, it has proved to be advantageous to cause the throughput of developer liquid per unit of length to decrease in the downward direction. By this means the result is achieved that the prints are completely free from blurring, which might otherwise be caused by developer liquid flowing downwardly.
  • This latter effect already is very much reduced by the arrangement according to the invention, as previously described, but it can be suppressed practically completely by the means referred to.
  • the decrease in the throughput may be effected in various ways. For example, it is possible to reduce the crosssection of the nozzle space 9 towards the lower portion. Furthermore, the gap widths 7 or 8 can be made narrower towards the lower portion. In the case of nozzles with a series of holes, the diameters of the holes can be continously reduced in the downward direction.
  • the supply reservoir and the delivery units for circulating the developer liquid are not shown in the drawings. These may be arranged in a conventional manner. It has proved to be advantageous to select an arrangement in which, on the one hand, developer liquid is forced out of the supply reservoir, through a feed hose 12 into the interior of the spray nozzle 9 and in which, on the other hand, the liquid admixed with air is drawn from outlets 13 and conveyed back to the supply reservoir.
  • the result of the second part of this operation is that a small negative pressure prevails in the spaces 10 and 11, so that even developer liquid which might otherwise escape laterally is drawn into these spaces.
  • This arrangement is very simple to achieve with two separate pumps. For this purpose it is possible to use all types of pumps in which only slight variations of the pressure occur.
  • Piston pumps therefore can be employed only with the interposition of air reservoirs. All types of rotary pumps can be used directly. Gear pumps have proved to be particularly suitable as pressure pumps. It is necessary only to take care when selecting the pumps that any packings contained therein consist of a material resistant against the dispersing agent of the developer, which is as a rule a hydrocarbon or a chlorinated hydrocarbon.
  • the delivery rate to be selected for the pump depends upon the rate of advance of the image carrier, the width of the apparatus and also upon the pressure head of the system.
  • care must be taken that a suction pump is selected in which the developer liquid is not homogenized too greatly with the air drawn off therewith. Otherwise, separation in the supply reservoir takes too long, so that an air-developer liquid mixture may be forced into the nozzles.
  • the conveyance of an image carrier with a latent electrostatic image through the space between the two hollow section bars in which there is a liquid curtain formed from the dispersion developer may, if desired, be effected manually. It is more appropriate, however, to effect the conveyance by means of suitable elements of the apparatus. Conveying rollers arranged in firont of and behind the hollow section bars and parallel thereto have proved to be suitable for this .purpose, such rollers bearing the reference numerals and 16 in FIGURE 1. The rollers may be moved up closer to the hollow section bars than is shown in FIGURE 1.
  • a conveyor belt 17 and two conveyor rollers 21 are shown in FIGURE 1 as a suitable device of this kind.
  • Both image carriers in individual sheet and in web from unwound from rolls can be developed with the apparatus which has been described. Furthermore, it is an advantage of the apparatus according to the invention that both direct prints and reversal .prints can be produced in it. Reversal prints can not be produced in every developing apparatus, since in reversal developing care must be taken that the developer does not reach the back of the image carrier. In the present apparatus, however, this is generally a normal feature.
  • One pole of a suitable source of direct-current voltage may be connected to the nozzle, which in this case must be made of metal, and the other pole to the roller or rollers, which is or are then also made of metal.
  • FIGURE 1 there is shown the projection plane 18 of a re-enlarging apparatus, this plane advantageously taking the form of a suction surface.
  • an inclined supporting strip 19 is mounted below the projection surface.
  • a sheet dispenser, indicated generally at 20, is advantageously combined with a charging device and pushes the charged, and hence light-sensitive, electrophotographic printing material onto the projection plane 18.
  • the conveyor means 17, 15, 16, and 21 are set in motion and move the image carrier through the developing apparatus. Very short developing times can be obtained, since the construction of the apparatus may be very compact.
  • the components can be even more closely associated than is shown in FIGURE 1.
  • An apparatus for developing latent electrostatic images using a dispersion developer which comprises at least one elongated nozzle means for producing developer spray, the nozzle means being mounted within a slot in one of two opposed hollow bar means having a space between them, each bar means having at least one longitudinal slot and the slots facing each other, and means for establishing a negative pressure Within the bar means.
  • An apparatus including conveying means for at least one edge of material to be developed.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
US583918A 1965-10-06 1966-10-03 Apparatus for developing latent electrostatic images Expired - Lifetime US3392707A (en)

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DEK0057318 1965-10-06

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US (1) US3392707A (fi)
AT (1) AT276943B (fi)
BE (1) BE687741A (fi)
ES (1) ES331915A1 (fi)
FR (1) FR1495971A (fi)
GB (1) GB1154543A (fi)
NL (1) NL151192B (fi)
SE (1) SE306882B (fi)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3461843A (en) * 1967-11-21 1969-08-19 Stanford Research Inst Toner application apparatus
US3618567A (en) * 1969-09-15 1971-11-09 Varian Associates Apparatus for developing latent electrographic images with liquid ink
US3643628A (en) * 1967-12-20 1972-02-22 Meyer L Sugarman Compact liquid toner apparatus with straight-through feed
US3656173A (en) * 1969-08-08 1972-04-11 Olivetti & Co Spa Liquid development of electrostatic images
US3662660A (en) * 1970-08-05 1972-05-16 Ronald P Layne Apparatus for processing sensitized material
US3675563A (en) * 1970-01-15 1972-07-11 Ibm Semiconductor processing apparatus
US3844786A (en) * 1972-03-03 1974-10-29 Fuji Photo Film Co Ltd Processing photographic materials
JPS507050U (fi) * 1973-05-17 1975-01-24
US3898957A (en) * 1972-12-28 1975-08-12 Ricoh Kk Developing unit for electrostatic latent image
US3916828A (en) * 1973-04-09 1975-11-04 Scott Paper Co Apparatus for developing an electrostatic latent image on an electrophotographic film
US3927639A (en) * 1974-04-08 1975-12-23 Scott Paper Co Apparatus for developing an electrostatic latent image on an electrophotographic film
US3972611A (en) * 1970-03-18 1976-08-03 Canon Kabushiki Kaisha Apparatus for transferring images produced by liquid developer
US4047950A (en) * 1974-04-08 1977-09-13 A. B. Dick/Scott Method for developing an electrostatic latent image on an electrophotographic film
EP0350875A2 (en) * 1988-07-12 1990-01-17 Kotobuki Sangyo Co., Ltd. Photographic processing unit
US5128721A (en) * 1988-02-12 1992-07-07 Nec Corporation Liquid development apparatus for developing a latent electrostatic image
US5761564A (en) * 1997-02-14 1998-06-02 Eastman Kodak Company Photographic processing apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2519831A1 (de) * 1975-05-03 1976-11-11 Platsch Zerstaeubung Albin Vorrichtung zur puderbestaeubung

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2289753A (en) * 1939-06-17 1942-07-14 Eastman Kodak Co Air squeegee
US2956494A (en) * 1956-01-13 1960-10-18 Kelvin & Hughes Ltd Application of liquid to surfaces
US3027821A (en) * 1958-06-18 1962-04-03 Hycon Mfg Company Film processing applicator
US3038442A (en) * 1958-12-29 1962-06-12 Burroughs Corp Electrostatic developing apparatus
US3168021A (en) * 1961-05-01 1965-02-02 Rca Corp Electrostatic printing
US3196832A (en) * 1963-02-20 1965-07-27 Rca Corp Fluid applicator apparatus
US3238921A (en) * 1963-03-14 1966-03-08 Dick Co Ab Electronic printing apparatus
US3270711A (en) * 1963-07-01 1966-09-06 Glasser Products Corp Electrostatic coating system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2289753A (en) * 1939-06-17 1942-07-14 Eastman Kodak Co Air squeegee
US2956494A (en) * 1956-01-13 1960-10-18 Kelvin & Hughes Ltd Application of liquid to surfaces
US3027821A (en) * 1958-06-18 1962-04-03 Hycon Mfg Company Film processing applicator
US3038442A (en) * 1958-12-29 1962-06-12 Burroughs Corp Electrostatic developing apparatus
US3168021A (en) * 1961-05-01 1965-02-02 Rca Corp Electrostatic printing
US3196832A (en) * 1963-02-20 1965-07-27 Rca Corp Fluid applicator apparatus
US3238921A (en) * 1963-03-14 1966-03-08 Dick Co Ab Electronic printing apparatus
US3270711A (en) * 1963-07-01 1966-09-06 Glasser Products Corp Electrostatic coating system

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3461843A (en) * 1967-11-21 1969-08-19 Stanford Research Inst Toner application apparatus
US3643628A (en) * 1967-12-20 1972-02-22 Meyer L Sugarman Compact liquid toner apparatus with straight-through feed
US3656173A (en) * 1969-08-08 1972-04-11 Olivetti & Co Spa Liquid development of electrostatic images
US3618567A (en) * 1969-09-15 1971-11-09 Varian Associates Apparatus for developing latent electrographic images with liquid ink
US3675563A (en) * 1970-01-15 1972-07-11 Ibm Semiconductor processing apparatus
US3972611A (en) * 1970-03-18 1976-08-03 Canon Kabushiki Kaisha Apparatus for transferring images produced by liquid developer
US3662660A (en) * 1970-08-05 1972-05-16 Ronald P Layne Apparatus for processing sensitized material
US3844786A (en) * 1972-03-03 1974-10-29 Fuji Photo Film Co Ltd Processing photographic materials
US3898957A (en) * 1972-12-28 1975-08-12 Ricoh Kk Developing unit for electrostatic latent image
US3916828A (en) * 1973-04-09 1975-11-04 Scott Paper Co Apparatus for developing an electrostatic latent image on an electrophotographic film
JPS507050U (fi) * 1973-05-17 1975-01-24
JPS5510996Y2 (fi) * 1973-05-17 1980-03-10
US3927639A (en) * 1974-04-08 1975-12-23 Scott Paper Co Apparatus for developing an electrostatic latent image on an electrophotographic film
US4047950A (en) * 1974-04-08 1977-09-13 A. B. Dick/Scott Method for developing an electrostatic latent image on an electrophotographic film
US5128721A (en) * 1988-02-12 1992-07-07 Nec Corporation Liquid development apparatus for developing a latent electrostatic image
EP0350875A2 (en) * 1988-07-12 1990-01-17 Kotobuki Sangyo Co., Ltd. Photographic processing unit
EP0350875A3 (en) * 1988-07-12 1990-10-31 Kotobuki Sangyo Co., Ltd. Photographic processing unit
US5761564A (en) * 1997-02-14 1998-06-02 Eastman Kodak Company Photographic processing apparatus

Also Published As

Publication number Publication date
NL151192B (nl) 1976-10-15
ES331915A1 (es) 1967-07-01
GB1154543A (en) 1969-06-11
DE1497168A1 (de) 1969-05-08
NL6613564A (fi) 1967-04-07
DE1497168B2 (de) 1976-03-25
BE687741A (fi) 1967-04-03
FR1495971A (fr) 1967-09-22
AT276943B (de) 1969-12-10
SE306882B (fi) 1968-12-09

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