US3769628A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for electrostatically recording with a closed loop web drive
Assignee: Varian Medical Systems Inc
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Filing: 1972-04-03
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Granted: 1973-10-30
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Expires: 1992-04-03
Abstract
Abstract A charge image is electrostatically recorded on a web through an array of writing electrodes. A stepping motor moves the web in response to a digital data source which also selects and activates the writing electrodes. The motor stepping and web motion is synchronized with the digital data input to the writing electrodes. The stepping motor is provided with a shaft encoder for detecting each step as it is completed and for feeding back this web change-in-position information to the digital data source. Upon receiving the step completion pulse, the digital data source releases the next raster of digital bits to the writing electrode array. Feedback between the shaft encoder and the digital data source preserves writing integrity on the web during start-up acceleration and subsequent deceleration of the web.
Inventors
- 👤 P Kenny
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:47
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/22; G03G15/32; G03G15/321; G03G15/325; Y; Y10; Y10S; Y10S101/00; Y10S101/37
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
298 words
An electrostatic recording apparatus for forming a charge image on the charge retentive surface of a recording medium in response to input signals, and for maintaining the proper spacing of the charge image regardless of variations in the speed of the recording medium or variations in the pulse rate of the input signals, the combination comprising: a stylus array formed by a plurality of writing electrodes mounted proximate the charge retentive surface of the recording medium; backplate means mounted proximate the other side of the recording medium and spaced from the stylus array to permit passage of the recording medium therebetween; data processing means responsive to the input signals for providing rasters of pulses for addressing and activating the stylus array and the backplate means to cause charge to transfer from selected styli to the charge retentive surface, and also for providing a step command pulse for advancing the recording medium; a motor logic circuit having a plurality of outputs and responsive to the step command pulses for providing winding step command pulses alternatively in the plurality of outputs; a variable speed stepping motor having a plurality of windings corresponding to the plurality of logic circuit outputs, each winding responsive to the winding step command pulses in the corresponding logic circuit output to rotate the stepping motor a defined angular step increment; drive means responsive to the angular steps of the stepping motor to drive the recording medium a corresponding linear step increment to move the recording medium past the stylus array; and detection means responsive to the step increment for generating a step completion pulse which is communicated to the data processing means to effect synchronization between the raster rate and the stepping rate for preserving the proper spacing of the charge image on the recording medium.
Claim 2
Dependent Claim
298 words
An electrostatic recording apparatus for forming a charge image on the charge retentive surface of a recording medium in response to input signals, and for maintaining the proper spacing of the charge image regardless of variations in the speed of the recording medium or variations in the pulse rate of the input signals, the combination comprising: a stylus array formed by a plurality of writing electrodes mounted proximate the charge retentive surface of the recording medium; backplate means mounted proximate the other side of the recording medium and spaced from the stylus array to permit passage of the recording medium therebetween; data processing means responsive to the input signals for providing rasters of pulses for addressing and activating the stylus array and the backplate means to cause charge to transfer from selected styli to the charge retentive surface, and also for providing a step command pulse for advancing the recording medium; a motor logic circuit having a plurality of outputs and responsive to the step command pulses for providing winding step command pulses alternatively in the plurality of outputs; a variable speed stepping motor having a plurality of windings corresponding to the plurality of logic circuit outputs, each winding responsive to the winding step command pulses in the corresponding logic circuit output to rotate the stepping motor a defined angular step increment; drive means responsive to the angular steps of the stepping motor to drive the recording medium a corresponding linear step increment to move the recording medium past the stylus array; and detection means responsive to the step increment for generating a step completion pulse which is communicated to the data processing means to effect synchronization between the raster rate and the stepping rate for preserving the proper spacing of the charge image on the recording medium.
Claim 3
Dependent Claim
81 words
The apparatus of claim 1, wherein the detection means is a shaft encoder responsive to the angular step increments of the stepping motor, the shaft encoder having a plurality of outputs corresponding to the plurality of windings of the stepping motor, and wherein the shaft encoder provides step completion pulses for each winding which are communicated to the motor logic circuit permitting the motor logic circuit to energize the windings sequentially and maintain stepping synchronism unaffected by externally generated noise pulses.
Claim 4
Dependent Claim
26 words
The apparatus of claim 2, wherein the stepping motor has three windings and the motor logic circuit and the shaft encoder have three outputs corresponding thereto.
Claim 5
Dependent Claim
33 words
The apparatus of claim 1, wherein the data processing means consists of a data source, and addressing means for the stylus array and the backplate, and driving means for the styli and backplate.
Claim 6
Dependent Claim
62 words
The apparatus of claim 1, wherein the step command pulse is provided by the data processing means immediately after each raster of pulses is provided to the stylus array and the backplate means by the data processing means, and the step completion pulse is communicated to the data processing means permitting the data processing means to release the next raster of pulses.
Claim 7
Independent Claim
106 words
A method of electrostatically recording a properly positioned charge image on a recording medium in response to input data, regardless of the speed of the recording medium or the rate of input data, the method comprising: providing a raster of pulses to a stylus array and a Backplate for selectively transferring charge to the recording medium positioned therebetween; providing a step command pulse for activating a stepping motor in increments which advances the recording medium in increments past the stylus array; detecting the completion of each increment; and providing a step completion pulse which maintains synchronism between the input rate and the stepping motor stepping rate.
Claim 8
Independent Claim
106 words
A method of electrostatically recording a properly positioned charge image on a recording medium in response to input data, regardless of the speed of the recording medium or the rate of input data, the method comprising: providing a raster of pulses to a stylus array and a Backplate for selectively transferring charge to the recording medium positioned therebetween; providing a step command pulse for activating a stepping motor in increments which advances the recording medium in increments past the stylus array; detecting the completion of each increment; and providing a step completion pulse which maintains synchronism between the input rate and the stepping motor stepping rate.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |