US3426354A - Electrostatic charge image recorder - Google Patents

Electrostatic charge image recorder Download PDF

Info

Publication number
US3426354A
US3426354A US371481A US37148164A US3426354A US 3426354 A US3426354 A US 3426354A US 371481 A US371481 A US 371481A US 37148164 A US37148164 A US 37148164A US 3426354 A US3426354 A US 3426354A
Authority
US
United States
Prior art keywords
drum
conductors
light source
insulating layer
scanning
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
US371481A
Other languages
English (en)
Inventor
Robert W Gundlach
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.)
Xerox Corp
Original Assignee
Xerox Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Priority to US371481A priority Critical patent/US3426354A/en
Priority to GB20465/65A priority patent/GB1084494A/en
Priority to NL6506350A priority patent/NL6506350A/xx
Priority to SE06968/65A priority patent/SE338117B/xx
Priority to DK274865AA priority patent/DK115269B/da
Priority to FR18979A priority patent/FR1455131A/fr
Priority to BE664729A priority patent/BE664729A/xx
Priority to CH766465A priority patent/CH444906A/fr
Priority to DER40767A priority patent/DE1280281B/de
Application granted granted Critical
Publication of US3426354A publication Critical patent/US3426354A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/23—Reproducing arrangements
    • H04N1/29—Reproducing arrangements involving production of an electrostatic intermediate picture
    • 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
    • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
    • G03G15/04036—Details of illuminating systems, e.g. lamps, reflectors
    • G03G15/04045—Details of illuminating systems, e.g. lamps, reflectors for exposing image information provided otherwise than by directly projecting the original image onto the photoconductive recording material, e.g. digital copiers
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/32—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head
    • G03G15/321—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head by charge transfer onto the recording material in accordance with the image
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/32—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head
    • G03G15/326—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head by application of light, e.g. using a LED array

Definitions

  • a xerographic recorder having a drum coated with a photoconductive material and having beneath said photoconductive material a plurality of parallel signal conductors separated from a grounded base conductor by a dielectric material, wherein the signal conductors are closely spaced to each other and extend along the width of the drum and terminate at one end thereof at terminals to which an electrical video signal is applied through a brush positioned to contact each of the individual terminals as the drum rotates, wherein latent electrostatic images are formed on the photoconductive material by scanning the surface of the photoconductive material along lines corresponding to the lengths of the signal conductors with a scanning spot of constant intensity and by applying the video signal through the brush to a signal conductor in the vicinity of the scan, wherein development of the latent image is accomplished by cascading triboelectrically charged toner particles over the photoconductive material with the developed image thereafter being transferred and fused onto a copy sheet, and wherein in another embodiment of the drum structure a di
  • Xeography as first described in US. Patent 2,297,691, and as amplified in many later related patents generally comprises uniformly charging a photoconductive insulating member, referred to in the art as a xerographic plate, to sensitize it, and then subjecting it to a light image or other pattern of activating electromagentic radiation which serves to dissipate charge in radiation-struck areas, thus leaving a charge pattern or latent electrostatic image on the photoconductor conforming to the electromagnetic radiation pattern.
  • the whole of the light image would not be exposed to the xerographic plate simultaneously but rather the xerographic plate would be scanned with a light source, the intensity of which is varied according to the input signal amplitude.
  • the image is developed by the deposition of electroscopic or electrostatically attractable, finely divided, colored material, referred to in the art as toner, on the exposed photoconductive insulator, which by virtue of its latent electrostatic image, forms a corresponding toner image on its surface.
  • the toner image thus formed may then optionally be viewed in situ on the photoconductive insulating layer or transferred to a copy sheet such as paper or other material for later use.
  • the toner image may be transferred to a copy sheet and a xerographic plate may immediately be cleaned and reused in the process for many thousands of cycles.
  • the cost of the selenium xerographic plate may be amortized over the many thousands of copies which it is capable of producing, the cost of photosensitive materials per copy is extremely low as compared with silver halide materials and the process is still capable of producing photo-exact reproductions of the facsimile originals transmitted from the source.
  • xerographic photo-facsimile recorder has a number of advantages over ordinary silver halide recorders including low cost, ease of development, fast access time, etc., it is somewhat slower in photographic speed than the fastest silver halide recording materials.
  • Yet another object of the invention is to provide a xerographic photorecording method of greatly increased s eed.
  • FIGURE 1 is a partially diagrammatic isometric view of a facsimile receiver constructed according to this invention, with some of the major system components removed;
  • FIGURE 2 is a view of the right-hand end of the apparatus seen in FIGURE 1 including additional apparatus components not shown in FIGURE 1;
  • FIGURE 3 is a broken partially sectioned end view of the drum illustrated in FIGURES 1 and 2;
  • FIGURE 4 is a top sectional view taken along section lines 44 of FIGURE 3.
  • FIGURE 5 is a broken partially sectioned end view of an alternate embodiment of the drum of FIGURE 3;
  • FIGURE 6 is an isometric view of an alternative high speed scanning mechanism.
  • FIGURE 1 a facsimile receiving system has been illustrated in isometric in FIGURE 1 as an exemplary illustration of the inventive concept.
  • a facsimile signal received through a transmission line from a facsimile transmitter is fed through input lines 10 to a demodulator 11 where it is separated from its carrier frequency prior to being fed into an input amplifier 12.
  • the input amplifier has its output connected to a small brush 13 which is mounted on a stationary support 14.
  • the brush 13 is of such a size and is so positioned that it makes electrical contact with each successive contact 15 on the insulating end face of a cylindrical drum generally designated 17 as the drum is rotated about its longitudinal axis.
  • each of the contacts 15 is electrically connected to one of a great number of mutually parallel conductors which are also parallel to the longitudinal axis of rotation of the drum 17 and imibedded in the drum close to its outer peripheral face, rotation of the drum at a time when an input signal is being received by the system causes the input signal to be switched from one very small longitudinal segment near the face of the drum to the next. This is perhaps best seen by viewing the conductor 5254 in FIGURE 4.
  • the system is constructed so as to cause the electrical input signal to scan around the drum surface, with this signal being applied to sequential line segments of the drum face which are taken along a line parallel to the drum axis.
  • the output signal of a very stable local oscillator 18 is fed into an amplifier 19 which in turn is employed to power a synchronous motor 21 that is used for mechanically driving the moving parts in the system.
  • a pinion 22 is mounted on the shaft of the synchronous motor 21 and is in driving engagement with another gear 23.
  • Gear 23 is mounted on the shaft 24 of drum 17 so that it directly rotates this drum in a direction indicated by the arrow in FIGURE 1.
  • a large gear 26 is also mounted for rotation on shaft 24 and is in driving engagement with a small pinion 27.
  • Pinion 27 is mounted on a shaft 28 in which there has been cut a reversing lead screw and on which there is mounted a carriage 29 for traversal back and forth in front of drum 17 as shaft 28 is rotated.
  • Carriage 29 carries a light source 31 and a lens 32 positioned to image light from source 31 on a very small spot on the surface of drum 17.
  • Light source 31 may consist of any high intensity, constant output light source such as a carbon arc lamp or the like.
  • the ability to use a constant high intensity light source in this system as opposed to the modulated light sources of other photofacsimile systems is a great advantage, especially in xerographic systems which generally employ materials with rela ively slo P graphic speeds since this allows for a great increase in scanning speeds.
  • Carriage 29 also contains a triangular hole which is utilized for mounting the carriage on a triangular guide bar 34 which in turn is mounted on a supporting stand 35. Although they are not illustrated in this figure so as to simplify the description of the invention, all shafts, the motor, and stand 35 are mounted on suitable rigid stationary supports. As described above, the electrical signal input to the system, after demodulation and amplification, is applied along whole line segments of the drum 17.
  • a latent electrostatic image is formed at the point Where a signal activated conductor intersects with the spot of light projected on the drum surface by light source 31 and lens 32, there is, in effect, a scanning across the drum by this light source and since the strength of the latent electrostatic image formed is dependent upon the magnitude of the input signal, the system is perhaps best understood by analogy to a cathode ra tube.
  • light source 31, lens 32, their carriage and traversing mechanism are analogous to the horizontal deflection plates of a cathode ray tube
  • the conductors running through the drum are analogous to the electron gun in a cathode ray tube.
  • This analogy holds because the scanning light determines where on the drum the latent electrostatic image will be formed and the signal on the conductor in the drum determines its strength or intensity.
  • Vertical scanning of the drum is accomplished by its rotation.
  • the transmitter and recorder must be operated in very close synchronism so that an image which closely corresponds to the original is reproduced in the recorder.
  • the original is placed on a transmitting drum of the same size as recording drum 17 and driven with a local oscillator, amplifier, synchronous motor and gear train identical to that employed in the recorder.
  • a light is placed on the original copy on the drum and a carriage carrying the light and a lens or lens system and p'hototube image the light reflected off a spot on the original copy onto the phototube.
  • This carriage is carried by a reversing lead screw similar to, and driven in the same manner as, lead screw 28 in the recording head.
  • the signal from the phototube is then fed to a modulator where it is mixed with a carrier frequency from a carrier signal generator, amplified and transmitted either on a transmission line or by radio propagation.
  • a modulator where it is mixed with a carrier frequency from a carrier signal generator, amplified and transmitted either on a transmission line or by radio propagation.
  • local oscillators of the same frequency in the transmitter and the recorder may be dispensed with and the system may rely for synchronization on the frequency control of the local power lines.
  • Other synchronization techniques Well known in the art such as employing the carrier for synchronization may also be employed.
  • the drive train in the illustrated recording system is continuous in nature.
  • the local oscillator 18, amplifier 19, and synchronous motor 21 are in continuous operation except when manually switched on and off.
  • a phasing system to place the beginning of a received scanning line at the left-hand edge of the recording would also be included.
  • a solenoid actuated clutch is included in the mechanical gear train and is actuated by a phase pulse amplifier operated by the system input,
  • the latent electrostatic image is formed on drum 17 by the combined action of light 31 and the electrical input signals, it is developed or made visible and transferrcd to a sheet of recording paper or other copy material.
  • Apparatus for accomplishing these developing and transfer Steps have not been illustrated in FIG. 1 for simplicity of illustration of other system concepts; however, in addition to many of the system components illustrated in FIG. 1, the additional developing and transfer system components are illustrated in some detail in FIG. 2.
  • FIG. 2 it is seen that once the latent electrostatic image is formed by the combined action of light source 31 and the electrical signal applied to the drum through brush 13, it passes a grounded brush 16, the purpose of which is described hereinafter, and then the drum rotates around so as to move past a developing unit generally designated 37.
  • This developing unit is of the cascade type which includes an outer container or cover 38 with a trough at its bottom containing a supply of developing material 39.
  • the developing material is picked up from the bottom of container 38 and dumped or cascaded over the drum surface by number of buckets 41 on an endless driven conveyor belt 42.
  • This development technique which is more fully described in US. Patent 2,618,552, to Wise and 2,618,551, to Walkup utilizes a two-clement developing mixture including finely divided, colored, marking particles, or toner, and grossly larger carrier beads.
  • the carrier beads serve both to deagglomerate the toner and to charge it by virtue of the relative positions of the toner and carrier material in the triboelectric series.
  • the electrostatic fields from the charge pattern on the drum pull toner particles off the carrier beads serving to develop the image.
  • the carrier beads along with any toner particles not used to develop the image then fall back into the bottom of container 38 and the developed image moves around until it comes into contact with a copy web 42 which is pressed up against the drum surface by two idle rollers 43 so that the web moves at the same speed as the periphery of the drum.
  • a transfer unit 44 is placed behind the web and spaced slightly from it between rollers 43.
  • the transfer unit illustrated contains one or more wire filaments which are connected to a source of high potential 45 and operate on the corona discharge technique as described in US.
  • Patents 2,588,699, to Carlson, and 2,777,957 to Walkup Essentially, this transfer technique which is described in US. Patent 2,576,047, to Schaffert, consists of spacing the filaments slightly from the surface to be charged, placing a grounded conductive base behind this surface and applying a high potential to the filament so that a corona discharge occurs between the filament and the surface, thus serving to deposit charged particles on the surface.
  • the polarity of potential source 45 and consequently the polarity of the charge deposited on the surface is opposite to that of the charge on the toner particles employed to develop the drum so that the charge deposited on copy web 42 serves to attract the toner particles away from the surface of the drum.
  • this deposited charge must be sufiicient to overcome the force of attraction between the particles and the charge of the latent electrostatic image formed on the drum.
  • development may be accomplished by magnetic brush development, as described in US. Patent 3,- 015,305, to Hall, or by powder cloud development, as described in US. Patent 2,918,900, to Carlson, and transfer may be accomplished by employing a roller connected to a high potential source opposite in polarity to the toner particles immediately behind the copy web or the copy web itself may be adhesive to the toner particles.
  • transfer may be accomplished by placing a grounded conductive plate behind the copy web at the point of transfer and applying a pulse of the same polarity as the charge on the toner particles to the conductors in the drum.
  • This transfer technique serves to repel the toner particles making up the developed image off the drum and onto the copy web.
  • the web moves beneath a fixing unit 4 6 which serves to fuse or permanently fix the toner image to web 42.
  • a resistance heating type fixer is illustrated; however, other fixing techniques known in the xerographic art may also be utilized including the subjection of the toner image to a solvent vapor or the spraying of the toner image with an overcoating.
  • the web is rewound on a coil 47 for later use.
  • the drum continues around and moves into a position where it is exposed to a strong light source 25 while its conductors are grounded through a brush 20. This dissipates all charge remaining at the photoconductor dielectric interface.
  • the drum then moves beneath a cleaning brush 48 which prepares it for a new cycle of operation.
  • FIGURE 3 there is illustrated a fragmentary partially sectional end view of one embodiment of the drum structure which my be employed in this invention.
  • This embodiment comprises a dielectric layer 50 on a grounded conductive backing member 51 which may also act as a rigid supporting structure for the drum.
  • Over dielectric layer 50 there are a number of electrically separated conductors 52, 53, 54, etc., which may desirably run in parallel lines in a direction parallel to the axis of rotation of the cylinder as seen in FIG. 1.
  • These conductors are very slender and thin and are uniformly spaced ranging from about 75 to about 350 conductors per inch of drum circumference although less or more conductors per inch may be employed depending upon considerations of image quality to be reproduced, cost and the like.
  • the conductors may cover on the order from about 30 to about 70% of the surface area of the underlying dielectric layer 50. These conductors may be placed on the supporting dielectric layer 50. These conductors may be placed on the supporting dielectric layer by means of photoresist and etch or engraving techniques which are well known in the printed circuit arts. It is also to be noted that if desired, the conductors may be embedded in the face of, or actually buried within dielectric layer 50; however, since the purpose of these conductors is to set up electrical fields through the uniform layer of photoconductive insulating material 56 overlying them, it is preferable that they be placed on the surface of the dielectric layer 50.
  • FIG. 4 is a partial section taken along section lines 4-4 of FIG. 3 which cuts through the drum along the top surface of conductors 52, 53, and 54. This section also cuts through the photoconductive insulating layer 56 in those portions of the drum which are not covered by the conductors 5254. As shown in FIG. 4, the photoconductive insulating layer 56 does not extend the whole width of the drum but only covers a portion of the dielectric base 50.
  • insulating end plate 57 which may be fabricated of the same material as layer 50 and are connected to a number of contacts on the right-hand surface of plate 57 for commutation with brush 13.
  • FIG. 5 there is illustrated a fragmentary partially sectional view of an alternate embodiment of the drum, the illustration of which is similar in nature to that of FIG. 3.
  • a number of electrioally separated parallel conductors 59, 60, 61, 62 and 63 similar to conductors 52-54 of FIGURE 3, are embedded in a dielectric layer 64.
  • This dielectric layer is overcoated with a photoconductive insulating layer 66.
  • the thickness of the dielectric material 64 between the conductors 59-63 and the photoconductive insulating layers 66 is kept quite thin so as to maximize the electrostatic field which will extend up to the photoconductive insulating layer from these conductors upon the application of an electrical potential to them.
  • the electrical input signal from the amplifier is applied across two adjacent conductors to set up the electrical field necessary to form a latent electrostatic image on the drum.
  • One method for accomplishing this result is to ground alternate conductors such as 59, 61, and 63, while connecting the conductors between these alternate conductors such as 60 and 62 to contacts such as 67 on the end face plate 68 of the drum. Then by grounding one output terminal of the input amplifier and connecting the other output terminal of this amplifier to brush 13, the output signal from the amplifier is applied across two adjacent conductors when brush 13 brushes against the contact 67 for one of those conductors.
  • the photoconductive insulating layer in either the FIG. 3 or FIG. 5 embodiment may, for example, consist of amorphous selenium, the xerographic use of which is more fully described in US. Patent 2,970,906, to Bixby.
  • Amorphous selenium is, of course, the preferred material for the photoconductive insulating layer of the drum since it produces excellent copy and is reusable in the process for many thousands of cycles. It is to be noted, however, that any other suitable photoconductive insulator may also be employed even when they are photographically slower than amorphous selenium and not reusable shortly after light exposure.
  • a prime example of this type of material is particulate French process zinc oxide in a film- -forming insulating binder such as a polystyrene or polyvinyl acetate resin.
  • This type of photoconductive insulating layer may, for example, be deposited on a dielectric film backing and the recording drum may be provided with grippers and/ or rollers to hold a cut dielectric sheet with the zinc oxide coating against the drum in close proximity to the conductors during one cycle of operation. After completion of the cycle, a fresh photoconductive insulating layer may be placed in the system either manually or with an automatic feed system in which, for example, the grippers for the photoconductive insulating layer may be cyclically cam actuated.
  • This type of system has the virtue that the transfer step may he eliminated from the overall process and the toner image may be fixed directly on the surface of the photoconductor.
  • FIGURE 6 Such a high speed scanning device is shown in FIGURE 6, and this device includes a light source 74, a lens 76 and an aperture 77, designed to focus a spot of light on a rotating hexagonal mirror 78, mounted on a shaft 79 which is driven by a synchronous motor drive 80.
  • the light After passing through aperture 77, the light is reflected oif whichever face of hexagonal minror 78 happens to be opposite the light source at that particular time, and is reflected through lens 81 to cylindrical recording drum 17 of the same type as described in connection with FIGURE 1 above.
  • 60 of rotation of hexagonal mirror 78 causes each mirror then opposite the light source to cause the light reflected 01f its surface to scan from one end of cylindrical drum 17 to the other end as shown by the arrow moving across the drum.
  • the next mirror face comes opposite the light source, it causes the light to once again scan the drum so that for each rotation of hexagonal mirror 78, the drum is scanned 6 times from right to left as seen in FIGURE 6.
  • the video signal is applied to the drum in the same manner as described above in connection with the FIGURE 1 embodiment of the invention and the rotational speed of cylindrical drum 17 is adjusted to coincide with the scanning rate of the light source.
  • the transmitter scanning head includes a light source, a lens system, and a phototube pickup so positioned and arranged as to cause a spot of light from the light source to be reflected off the transmitting drum to the phototube pickup.
  • the scanning head when the scanning head light strikes a white or lightcolored portion of the original, it reflects a large amount of light back to the phototube, whereas when this light strikes a dark or black portion of the original, most of the light is absorbed and very little is reflected back to the phototube pickup. Consequently, the potential appearing at the phototube output is directly proportional to the lightness or darkness of the particular small elemental area of the original being scanned at any particular time. Since the rate of travel of the scanning head across the drum is high with respect to the speed of rotation of the drum, the whole surface area of the original on the transmitter drum is scanned one elemental area at a time in a line-by-line fashion.
  • the output signal of the phototube is mixed with a carrier frequency and transmitted either over a transmisison line or by radio propagation to the receiver which then demodulates and amplifies this signal prior to applying it to brush 13.
  • This brush makes electrical contact with one of contacts 15 on the end face of the recording drum 17.
  • the ratio between gear 26, which is mounted on the shaft of the drum 17, and gear 27, which is mounted on the shaft carrying the lead screw for carriage 29, is selected so that brush 13 makes electrical connection with one or several of the contacts 15 for a time interval equal to the time required for the scanning spot of light to make one traversal across the full width of the photoconductive insulating layer 33 on the drum surface.
  • This means that the varying electrical input signal is continuously applied to one or several of the conductors in the drum as light source 31 on the carriage 29 scans across the photoconductive insulating layer 33 directly above the activated conductor or conductors.
  • FIG. 3 it is seen that when an electrical signal is applied to one of the conductors such as 52, 53, or 54, an electrical field is set up between the conductor and the grounded conductive backing plate 51 of this drum embodiment. Although some of the field lines proceed directly from the bottom of the conductor to the conductive grounded plate 51, other field lines curve up from the top of these conductors through the photoconductive insulating layer 56 and then down through the photoconductive insulating layer between adjacent conductors through the dielectric layer 50 to the grounded conductive backing layer 51.
  • Whether or not an electrical field is set up in the photoconductive insulating layer 56 is thus dependent upon whether or not a signal is applied to one of the conductors 52-54, and its instantaneous strength is dependent upon the instantaneous amplitude of the electrical signal being applied. If the photoconductive insulating layer 56 is not subjected to exposure by light or other Iactivating electromagnetic radiation, it will, of course, remain in its most insulating condition so that charge carriers within it will have little or no mobility. On the other hand, if any section of the photoconductive insulating layer is exposed to light, the illuminated areas will become relatively more conductive.
  • an electric field when applied to a conductor, causes the charge carriers within it to move in such a way as to make the interior of the conductor a field-free, equi-potential volume.
  • the electric field resulting from the application of the signal between this conductor and the grounded conductive backing plate 51 would cause the free electrons in this conductive area of the photoconductive insulating layer 56 to move toward the grounded plate 51 (assuming that the applied signal had a negative polarity).
  • the polarity of charge trapped at the interface is dependent upon the polarity of the applied signal so that if the signal is negative, negative charge will be trapped at the photoconductordielectric interface while if the signal is positive, positive charge will be trapped at the photoconductor-dielectric interface.
  • Each of the small conductors 52-54 makes up an individual capacitor in conjunction with the dielectric layer 50 and a common second capacitor plate 51 so that some charge may be stored in each of these small capacitors. It is thus seen that the application of a signal across the capacitor plate for the purpose of trapping charge at the photoconductor-dielectric interface will also serve to store some charge in each of these small capacitors.
  • these capacitors are shorted so as to discharge them by connecting them through contacts 15 to a grounded brush 16 once the photoconductive insulating layer above them has passed out of the range of the light source 31 and the required charge has been stored at the photoconductor-dielectric interface by the signal input.
  • the recorder Since the instantaneous value of the signal received by the recorder is the electrical analog of the reflectivity of that portion or elemental area of the original document being scanned by the transmitter, and since the recorders scanning light source 31 is closely synchronized with the transmitters scanning pickup, an electrostatic latent image is formed on the recording drum which exactly corresponds to the image on the original.
  • light source 31 is a traversing optical switch which allows the formation of a latent electrostatic image at the point where it has virtual intersection with one of the conductors in the recording drum providing that conductor is carrying an input signal at that particular time.
  • the latent electrostatic image thus formed is then developed and transferred to a copy web, as described above.
  • the drum shown in the FIGURE embodiment of this invention operates in a manner similar to that of the FIGURE 3 drum, except that, instead of using a plurality of fine separated conductors in the selenium which are separated from a common grounded conductive backing plate by a dielectric layer, all conductors are imbedded in the dielectric layer so that they are mutually insulated from each other with alternate conductors being grounded so as to substitute for the conductive backing layer 51 of the FIGURE 3 embodiment.
  • This alternate conductor grounding may also be used with the FIGURE 3 device.
  • the drum components may be made substantially transparent and scanning light exposure may be made from within the drum.
  • the drum itself may be made in the form of a fiat plate rather than a cylindrical drum and scanned by linear movement of this plate with respect to the scanning light source.
  • a rocking concave mirror may project light from a light source onto the drum surface or a rotating hexagonal mirror may be employed for the same purpose.
  • Other methods of transmission including sampling circuits and pulse and coding techniques, may be employed as well as many other Well-known synchronizing methods. In short, the list of alternatives is virtually endless.
  • a transducer for the conversion of an electrical signal to a latent electrostatic image comprising a photoconductive insulating layer
  • said second conductor being closely spaced to said first conductors and separated therefrom by said dielectric material
  • said first and second conductors being on a first side of said photoconductive insulating layer, a source of high intensity electromagnetic radiation to which said photoconductive layer is sensitive,
  • a transducer according to claim 1 in which said first conductors are close to each other and mutually parallel.
  • a transducer according to claim 1 further including means to electrically connect said first and second conductors after they have been scanned by said electromagnetic radiation source.
  • a recorder for the conversion of electrical signals into visible images comprising a photoconductive insulating layer
  • first electrically separated conductors contiguous to said photoconductive insulating layer, said first conductors being separated from at least one closely spaced second conductor by a dielectric material, said first and second conductors being on a first side of said photoconductive insulating layer, means to scan areas of a second side of said photoconductive insulating layer opposite said first side, said scan covering portions corresponding to the length of successive first conductors, with a high intensity source of electromagnetic radiation to which said photoconductive insulating layer is sensitive,
  • An image recorder further including means to transfer the visible image made up of said deposited electroscopic marking particles from said photoconductive insulating layer to another surface.
  • An image recorder further including means to discharge any residual electrostatic charge remaining on said photoconductive insulating layer after a particulate image has been transferred whereby said recorder is prepared for reuse.
  • discharge means comprises means to ground said first and second conductors and means to simultaneously uniformly expose said photoconductive insulating layer to a source of electromagnetic radiation to which it is sensitive.
  • a transducer for the conversion of an electrical signal to a latent electrostatic image comprising a photoconductive insulating layer
  • said first and second conductors being on a first side of said photoconductive insulating layer
  • a transducer in which said photoconductive insulating layer is in the form of a cylinder, and said means to advance the point of scanning light impingment comprises means to rotate said cylinder about its longitudinal axis and said means to scan said photoconductive insulating layer in a direction parallel to said first conductors comprises means to cause traversal of scanning radiation impingement along the cylinder surface in a direction parallel to the longitudinal axis of said cylinder.
  • An electrical signal to latent electrostatic image transducer comprising a photoconductive insulating layer

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
US371481A 1964-06-01 1964-06-01 Electrostatic charge image recorder Expired - Lifetime US3426354A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US371481A US3426354A (en) 1964-06-01 1964-06-01 Electrostatic charge image recorder
GB20465/65A GB1084494A (en) 1964-06-01 1965-05-14 Video recorder
NL6506350A NL6506350A (fr) 1964-06-01 1965-05-19
SE06968/65A SE338117B (fr) 1964-06-01 1965-05-26
DK274865AA DK115269B (da) 1964-06-01 1965-05-31 Omsætter til ved xerografi at omdanne et indkommende elektrisk signal til et latent elektrostatisk billede.
FR18979A FR1455131A (fr) 1964-06-01 1965-05-31 Enregistreur vidéo
BE664729A BE664729A (fr) 1964-06-01 1965-05-31
CH766465A CH444906A (fr) 1964-06-01 1965-06-01 Procédé et dispositif de conversion d'un signal électrique en image graphique
DER40767A DE1280281B (de) 1964-06-01 1965-06-01 Verfahren und Anordnung zur Umwandlung eines elektrischen Signals in ein graphisches Bild

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US371481A US3426354A (en) 1964-06-01 1964-06-01 Electrostatic charge image recorder

Publications (1)

Publication Number Publication Date
US3426354A true US3426354A (en) 1969-02-04

Family

ID=23464156

Family Applications (1)

Application Number Title Priority Date Filing Date
US371481A Expired - Lifetime US3426354A (en) 1964-06-01 1964-06-01 Electrostatic charge image recorder

Country Status (9)

Country Link
US (1) US3426354A (fr)
BE (1) BE664729A (fr)
CH (1) CH444906A (fr)
DE (1) DE1280281B (fr)
DK (1) DK115269B (fr)
FR (1) FR1455131A (fr)
GB (1) GB1084494A (fr)
NL (1) NL6506350A (fr)
SE (1) SE338117B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4000944A (en) * 1975-02-18 1977-01-04 Xerox Corporation Photoreceptor for electrostatic reproduction machines with built-in electrode
US4103994A (en) * 1977-02-11 1978-08-01 Xerox Corporation Recording plate

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3062956A (en) * 1960-04-04 1962-11-06 Xerox Corp Xerographic charging apparatus
US3090828A (en) * 1960-03-28 1963-05-21 Itt System for large-area display of information
US3199086A (en) * 1960-11-25 1965-08-03 Rahn Corp Devices exhibiting internal polarization and apparatus for and methods of utilizing the same
US3288602A (en) * 1962-04-04 1966-11-29 Xerox Corp Xerographic plate and method
US3301947A (en) * 1963-04-01 1967-01-31 Dick Co Ab Electrostatic image copier having photoconductive element switching
US3308233A (en) * 1963-09-09 1967-03-07 Xerox Corp Xerographic facsimile printer having light beam scanning and electrical charging with transparent conductive belt
US3308234A (en) * 1963-12-30 1967-03-07 Xerox Corp Facsimile recorder using thermoplastic record with photoconductive layer

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2588699A (en) * 1943-08-27 1952-03-11 Chester F Carlson Electrophotographic apparatus
US2618552A (en) * 1947-07-18 1952-11-18 Battelle Development Corp Development of electrophotographic images
US2618551A (en) * 1948-10-20 1952-11-18 Haloid Co Developer for electrostatic images
US2576047A (en) * 1948-10-21 1951-11-20 Battelle Development Corp Method and apparatus for printing electrically
US2777957A (en) * 1950-04-06 1957-01-15 Haloid Co Corona discharge device
US2970906A (en) * 1955-08-05 1961-02-07 Haloid Xerox Inc Xerographic plate and a process of copy-making
US2918900A (en) * 1955-08-30 1959-12-29 Haloid Xerox Inc Apparatus for xerographic development
US3015305A (en) * 1958-05-23 1962-01-02 Xerox Corp Development of electrostatic images

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3090828A (en) * 1960-03-28 1963-05-21 Itt System for large-area display of information
US3062956A (en) * 1960-04-04 1962-11-06 Xerox Corp Xerographic charging apparatus
US3199086A (en) * 1960-11-25 1965-08-03 Rahn Corp Devices exhibiting internal polarization and apparatus for and methods of utilizing the same
US3288602A (en) * 1962-04-04 1966-11-29 Xerox Corp Xerographic plate and method
US3301947A (en) * 1963-04-01 1967-01-31 Dick Co Ab Electrostatic image copier having photoconductive element switching
US3308233A (en) * 1963-09-09 1967-03-07 Xerox Corp Xerographic facsimile printer having light beam scanning and electrical charging with transparent conductive belt
US3308234A (en) * 1963-12-30 1967-03-07 Xerox Corp Facsimile recorder using thermoplastic record with photoconductive layer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4000944A (en) * 1975-02-18 1977-01-04 Xerox Corporation Photoreceptor for electrostatic reproduction machines with built-in electrode
US4103994A (en) * 1977-02-11 1978-08-01 Xerox Corporation Recording plate

Also Published As

Publication number Publication date
BE664729A (fr) 1965-09-16
SE338117B (fr) 1971-08-30
DE1280281B (de) 1968-10-17
NL6506350A (fr) 1965-12-02
FR1455131A (fr) 1966-10-14
DK115269B (da) 1969-09-22
CH444906A (fr) 1967-10-15
GB1084494A (en) 1967-09-20

Similar Documents

Publication Publication Date Title
US2901374A (en) Development of electrostatic image and apparatus therefor
US3782818A (en) System for reducing background developer deposition in an electrostatic copier
US3430254A (en) Tesi printing with flexible electrode on endless belt
US3890929A (en) Xerographic developing apparatus
US3043685A (en) Xerographic and magnetic image recording and reproducing
US2885955A (en) Xerographic machine
US2878120A (en) Intermittent electrophotographic recorder
US2968552A (en) Xerographic apparatus and method
US3752572A (en) Apparatus for making electrographs
US3166418A (en) Image development
US3630608A (en) High-speed copier
US3332396A (en) Xerographic developing apparatus with controlled corona means
US2932690A (en) Apparatus for image reproduction
US3190199A (en) Xerographic copying apparatus
US3308233A (en) Xerographic facsimile printer having light beam scanning and electrical charging with transparent conductive belt
US4509850A (en) Two-color electrophotographic printing machine
US3549251A (en) Electrophotographic method and apparatus
US4675261A (en) Electrophotographic process with a photoconductive screen
US3730709A (en) Method for electrophotography
US3426354A (en) Electrostatic charge image recorder
US3396235A (en) Xerographic facsimile printer having light scanning and electrical charging
US4572647A (en) Hybrid development system
US3241466A (en) Electrostatic photography
US4694310A (en) Method and apparatus of electrophotography
CA1327834C (fr) Imprimante ionographique a laser