US3653758A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressureless non-contact electrostatic printing
Assignee: Frye Ind Inc
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Filing: 1970-07-10
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Granted: 1972-04-04
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Expires: 1990-07-10
Abstract
Abstract A pre-determined, non-random electrostatic image is formed and developed on a thin, flexible plate about 0.0005 to about 0.050 inch thick. A substrate to be printed is positioned facing but spaced apart from this pre-formed image of particles, and an electrostatic field is established therebetween. The field is of insufficient strength to dislodge the image of particles from the thin plate, but of sufficient strength to transfer the image to the substrate once it is dislodged from said thin plate. The additional force required to dislodge the particles is supplied by imparting ultrasonic flexual shock waves to the thin plates. The dislodging effect of the shock waves is enhanced by exciting the vibratory system at a resonance frequency of said system. The electrostatic attraction between the image of particles and the thin plate serves to minimize any tendency for relative lateral movement of the particles upon application of the ultrasonic shock waves, thereby causing the particles to be propelled directly outward from the thin plate in their desired image configuration and permitting the reproduction of the image with superior clarity and sharpness on the spaced-apart substrate. By sweeping the driving frequency through a range including a resonance frequency of the vibratory system, several distinct resonances of the thin plate will be effected, thereby superimposing several nodal patterns on said thin plate so as to minimize variations in the particle intensity of the reproduced image and further enhancing the quality of said image. For continuous operations, the thin plate is conveniently employed in the form of a rotatably mounted continuous belt, with a cleaning station, a charging station, a development station, and an image transfer station positioned along the path of rotation. A metallic belt may be employed with a non-conductive image formed thereon by coating the plate with a light sensitive photo-resist material, exposing the coating to light through a negative of the desired image and developing the thus exposed image by dissolving the unexposed, non-image areas with an organic solvent. The flexual waves may be generated in the thin plate by a piezoelectric crystal system. When the thin plate is used in the form of a continuous belt, the piezoelectric crystal system may conveniently be affixed or otherwise connected to one of the belt-supporting rollers. The piezoelectric crystals may also be incorporated as an integral part of such a roller for greater convenience and control in continuous printing operations. Excitation of the crystal system can occur nearly instantaneously when the printing gap is less than about one-eighth inch. At about three-sixteenth inch or more, the amplitude of the excitation signal may be increased slowly, and the driving frequency may be swept slowly to limit the instantaneous toner current in the gap and avoid mutual repulsion of particles and some distortion of the reproduced image.
Inventors
- 👤 Donald S Trimmer
- 👤 Walter B Bienert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:05
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
378 words
An improved pressureless, non-contact electrostatic printing process for the transfer of a pre-formed image of dielectric particles to an image-receiving substrate comprising: a. forming a predetermined, non-random image of charged dielectric particles in the form desired to be printed at an image-forming zone on a thin, flexible image-forming plate in the form of a rotatably mounted continuous belt capable of being flexed at ultrasonic frequencies; b. rotating said thin plate so that said image of particles thereon is positioned at an image transfer zone; c. positioning said image-receiving substrate facing the image of particles but spaced apart therefrom at said image transfer zone; d. establishing an electrostatic field between said imagereceiving substrate and said image of particles on said thin plate, said field being of insufficient strength to effect by itself the practical dislodgement of the image of particles from said thin plate but of sufficient strength to effect the transfer of said image of particles to the image-receiving substrate in the form desired to be printed thereon once dislodged from said thin plate; and e. exciting at an ultrasonic frequency a piezoelectric crystal positioned in one of the support rollers serving to position the image-bearing section of said thin plate in the image transfer zone, thus imparting mechanical vibratory shock waves in the ultrasonic range through said roller to said thin plate so as to transmit to said image of particles ultrasonic shock waves of sufficient magnitude to assist said electrostatic field in overcoming the forces tending to cause at least a substantial portion of the particles to adhere to their preformed position on the surface of the thin plate, whereby the practical dislodgement of the particles pre-formed in the desired image configuration may be effected, and the image of particles may be transferred to and reproduced on the spacedapart substrate in the form desired to be printed thereon at an electrostatic field intensity less than that required for transfer by means of the electrostatic field alone, the relatively close spacing of the nodal patterns of the ultrasonic vibrational shock waves imparted to said thin plate being flexed and transmitted thereby to said image of particles serving to enhance the clarity and sharpness of the image transferred to and reproduced on the spaced-apart substrate to be printed.
Claim 2
Dependent Claim
378 words
An improved pressureless, non-contact electrostatic printing process for the transfer of a pre-formed image of dielectric particles to an image-receiving substrate comprising: a. forming a predetermined, non-random image of charged dielectric particles in the form desired to be printed at an image-forming zone on a thin, flexible image-forming plate in the form of a rotatably mounted continuous belt capable of being flexed at ultrasonic frequencies; b. rotating said thin plate so that said image of particles thereon is positioned at an image transfer zone; c. positioning said image-receiving substrate facing the image of particles but spaced apart therefrom at said image transfer zone; d. establishing an electrostatic field between said imagereceiving substrate and said image of particles on said thin plate, said field being of insufficient strength to effect by itself the practical dislodgement of the image of particles from said thin plate but of sufficient strength to effect the transfer of said image of particles to the image-receiving substrate in the form desired to be printed thereon once dislodged from said thin plate; and e. exciting at an ultrasonic frequency a piezoelectric crystal positioned in one of the support rollers serving to position the image-bearing section of said thin plate in the image transfer zone, thus imparting mechanical vibratory shock waves in the ultrasonic range through said roller to said thin plate so as to transmit to said image of particles ultrasonic shock waves of sufficient magnitude to assist said electrostatic field in overcoming the forces tending to cause at least a substantial portion of the particles to adhere to their preformed position on the surface of the thin plate, whereby the practical dislodgement of the particles pre-formed in the desired image configuration may be effected, and the image of particles may be transferred to and reproduced on the spacedapart substrate in the form desired to be printed thereon at an electrostatic field intensity less than that required for transfer by means of the electrostatic field alone, the relatively close spacing of the nodal patterns of the ultrasonic vibrational shock waves imparted to said thin plate being flexed and transmitted thereby to said image of particles serving to enhance the clarity and sharpness of the image transferred to and reproduced on the spaced-apart substrate to be printed.
Claim 3
Dependent Claim
28 words
The process of claim 1 in which said thin plate is excited at a driving frequency within the range of from about 20 kHz. to about 100 kHz.
Claim 4
Dependent Claim
63 words
The process of claim 2 in which said driving frequency comprises a resonance frequency of said vibrating system so that a standing vibrational shock wave is created in said thin plate, thereby maximizing the amplitude of the mechanical shock imparted to said image of particles by said ultrasonic vibration transmitted to said thin, flexible plate by said piezoelectric crystal in said support roller.
Claim 5
Dependent Claim
41 words
The process of claim 3 in which the amplitude of the excitation signal is raised from a lower value to full value and the driving frequency is swept through a range incLuding at least one resonance frequency of the vibratory system.
Claim 6
Dependent Claim
53 words
The process of claim 4 in which said driving frequency is swept through a range of about 2 to about 10 kHz including said resonance of the vibrating system, thereby exciting the thin plate at a series of resonances thereof thereby extinguishing any discernible intensity production of the image reproduced on the substrate.
Claim 7
Dependent Claim
86 words
The process of claim 1 in which said thin plate is a metallic plate and the forming of the predetermined image of particles thereon comprises: a. forming an electrostatic image on the surface of said plate in said predetermined, non-random image configuration; and b. developing said electrostatic image by contacting said plate surface with charged dielectric particles of opposite polarity to that of said electrostatic image, said dielectric particles thus being retained preferentially on the surface of said plate by electrostatic forces in the image areas.
Claim 8
Dependent Claim
159 words
The process of claim 6 in which the forming of said electrostatic image on the surface of said thin plate comprises: a. coating at least a portion of said thin plate with a light sensitive, photo-resist insulating material soluble in organic solvents; b. exposing said coating to light through a negative of the desired image to form a light sensitized latent image on said coating, the thus exposed image areas of said coating material being insoluble in said organic solvents; c. developing said latent image by dissolving said coating preferentially in the unexposed, non-image areas thereof with an organic solvent therefor, thus leaving an insulating image of exposed coating material on the surface of said metallic plate; and d. charging said thin plate by means of a corona discharge, said charge being retained by the insulating material in the exposed image areas of the plate and being dissipated to ground in the unexposed, non-image conductive areas of said plate.
Claim 9
Dependent Claim
54 words
The process of claim 6 in which the rotation of said continuous belt is stopped when the image-bearing section thereof is positioned at said image-transfer zone, facing but spaced apart from said image-receiving substrate, and the rotation of said belt is thereafter continued following transfer of said image of particles to the image-receiving substrate.
Claim 10
Dependent Claim
66 words
The process of claim 6 in which the rotation of said continuous belt is continued as the section thereof bearing an image of particles passes through said image transfer zone, facing but spaced apart from said image-receiving substrate, said substrate also being continuously moved so as to maintain proper registry between said image-bearing section of the continuous belt and said substrate during the image transfer operation.
Claim 11
Dependent Claim
43 words
The process of claim 6 and including the cleaning of the image section of said continuous belt after said section leaves the image transfer zone and prior to the forming of the next electrostatic image thereon as said image transfer operations are continued.
Claim 12
Dependent Claim
403 words
An improved pressureless, non-contact electrostatic printing apparatus for the transfer of a pre-formed image of dielectric particles to an image-receiving substrate comprising: a. a thin, flexible image-forming plate adapted to receive the desired image to be printed, said plate being in the form of a rotatably mounted continuous belt capable of being flexed at ultrasonic frequencies; b. means for applying charged dielectric particles to said thin plate; c. means for retaining said particles preferentially in the desired image areas of said thin plate; d. a conductive member positioned in spaced relationship to said thin plate at an image transfer zone; e. electrical means for establishing an electrostatic field operable between said thin plate and the conductive member; f. means for positioning the substrate to be printed within the electrostatic field between said thin plate and said conductive member, said substrate facing said thin platE but spaced apart therefrom; and g. piezoelectric crystal means for applying mechanical vibratory shock waves in the ultrasonic range to the portion of said thin plate positioned at said image transfer zone, said piezoelectric crystal means being positioned in one of the belt-supporting rollers serving to position the image-bearing section of said continuous belt in the image transfer zone, the ultrasonic shock waves generated in said roller serving to create ultrasonic flexual waves in said continuous belt so as to impart to said image of particles thereon ultrasonic shock waves of sufficient magnitude to assist said electrostatic field in overcoming the forces tending to cause at least a substantial portion of the particles to adhere to their pre-formed position on the surface of the thin plate, thus facilitating the practical dislodgement of the particles from the thin plate and the subsequent migration thereof to the substrate at the image transfer zone, whereby the particles pre-formed in the desired image configuration may be dislodged from the thin plate, transferred to and reproduced on the spaced-apart substrate in the form desired to be printed thereon at an electrostatic field intensity less than that required for transfer by means of the electrostatic field alone, the uniformity with which said thin plate can be flexed and the relatively close spacing of the nodal pattern of said ultrasonic vibrational shock waves imparted to said thin plate and transmitted to said image of particles serving to enhance the clarity and sharpness of the image transferred to and reproduced on the spaced-apart substrate to be printed.
Claim 13
Dependent Claim
403 words
An improved pressureless, non-contact electrostatic printing apparatus for the transfer of a pre-formed image of dielectric particles to an image-receiving substrate comprising: a. a thin, flexible image-forming plate adapted to receive the desired image to be printed, said plate being in the form of a rotatably mounted continuous belt capable of being flexed at ultrasonic frequencies; b. means for applying charged dielectric particles to said thin plate; c. means for retaining said particles preferentially in the desired image areas of said thin plate; d. a conductive member positioned in spaced relationship to said thin plate at an image transfer zone; e. electrical means for establishing an electrostatic field operable between said thin plate and the conductive member; f. means for positioning the substrate to be printed within the electrostatic field between said thin plate and said conductive member, said substrate facing said thin platE but spaced apart therefrom; and g. piezoelectric crystal means for applying mechanical vibratory shock waves in the ultrasonic range to the portion of said thin plate positioned at said image transfer zone, said piezoelectric crystal means being positioned in one of the belt-supporting rollers serving to position the image-bearing section of said continuous belt in the image transfer zone, the ultrasonic shock waves generated in said roller serving to create ultrasonic flexual waves in said continuous belt so as to impart to said image of particles thereon ultrasonic shock waves of sufficient magnitude to assist said electrostatic field in overcoming the forces tending to cause at least a substantial portion of the particles to adhere to their pre-formed position on the surface of the thin plate, thus facilitating the practical dislodgement of the particles from the thin plate and the subsequent migration thereof to the substrate at the image transfer zone, whereby the particles pre-formed in the desired image configuration may be dislodged from the thin plate, transferred to and reproduced on the spaced-apart substrate in the form desired to be printed thereon at an electrostatic field intensity less than that required for transfer by means of the electrostatic field alone, the uniformity with which said thin plate can be flexed and the relatively close spacing of the nodal pattern of said ultrasonic vibrational shock waves imparted to said thin plate and transmitted to said image of particles serving to enhance the clarity and sharpness of the image transferred to and reproduced on the spaced-apart substrate to be printed.
Claim 14
Dependent Claim
20 words
The apparatus of claim 11 in which said thin plate is from about 0.005 to about 0.050 inch in thickness.
Claim 15
Dependent Claim
17 words
The apparatus of claim 12 in which said thickness is from about 0.001 to about 0.010 inch.
Claim 16
Dependent Claim
31 words
The apparatus of claim 11 in which said piezoelectric crystal means is capable of activation at a driving frequency within the range of from about 20 kHz to about 100 kHz.
Claim 17
Dependent Claim
24 words
The apparatus of claim 14 and including means to sweep a driving frequency range including at least one resonance frequency of the vibratory system.
Claim 18
Dependent Claim
23 words
The apparatus of claim 11 in which said crystal means comprises at least one piezoelectric disc forming a part of said support roller.
Claim 19
Dependent Claim
24 words
The apparatus of claim 11 in which said crystal means comprises at least one piezoelectric tubular crystal forming a part of said support roller.
Claim 20
Dependent Claim
33 words
The apparatus of claim 11 in which said thin plate is a thin metallic plate having an insulating image in the form desired to be printed positioned on at least a portion thereof.
Claim 21
Dependent Claim
112 words
The apparatus of claim 18 in which said means for applying said particles to the plate and for retaining said particles in the image areas thereof comprises: a. a charging station at which a corona wire is positioned to impart an electrostatic charge to said plate, the charge being retained in the insulating image areas and being dissipated to ground in the metallic non-image areas thereof, said charging station being positioned along the path of rotation of said continuous belt in advance of the development station; and b. a development station positioned along the path of rotation of said continuous belt subsequent to said charging station but prior to said image-transfer zone.
Claim 22
Dependent Claim
47 words
The apparatus of claim 19 and including a cleaning station comprising mechanical means for removing residual particles from said continuous belt, said cleaning station being positioned along the path of rotation of said continuous belt subsequent to said image transfer zone but prior to said charging station.
Claim 23
Dependent Claim
29 words
The apparatus of claim 11 in which said crystal means comprises at least two crystals and means for activating said crystals in unison at frequencies in the ultrasonic range.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-04 | 1975-10-04 | 1976-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-04 | 1979-10-04 | 1980-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-04 | 1983-10-04 | 1984-04-04 | $7700.00 | Window Closed / Lapsed |