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EP0051393A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Apparatus for making copies at different magnifications

Assignee: Xerox Corp
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Filing: 1981-10-21
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Granted: —
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Expires: 2001-10-21
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Abstract

Abstract A reproduction apparatus for producing copies of a document selectively at one of a plurality of copy image magnification ratios. The apparatus includes a microprocessor for control of the optical components for variable magnification, the control including a bidirectional AC motor (41) a reference potentiometer (42), an analog to digital (A/D) converter (98), and triacs (94, 96) for driving the motor. The potentiometer voltage represents the present position of the optical components in the reproduction machine. The position of the optical components determines the actual magnification ratio of images. Upon selection of a particular magnification ratio, a digital position word from memory (99) corresponding to the selected magnification ratio is compared (102) to the optical component current position voltage converted through the AID converter (98). Depending upon the error signal generated by the compare operation, a run bit is set to activate the motor in the direction to minimize the error signal and position the optical components to achieve the magnification ratio selected. As the optical components near the desired locations, the motor is selectively pulsed to progressively decrease the duty cycle of operation. For example, the duty cycle of operation is decreased from 100 percent to 70 percent, 50 percent, and 30 percent to slowly position the optical components and minimize inertia effects.

Inventors

  • 👤 William G. Miller

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-02 08:33
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/04; G03G15/041

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 117 words
A reproduction apparatus for producing copies of a document selectively at one of a plurality of copy image magnification ratios including a photosensitive surface (12), a magnification selector (103), and an optical arrangement (36, 38, 40) for projecting images onto the photosensitive surface at a selected magnification, the apparatus being characterised by a control (90) with associated memory (100), means for reading a word from memory (99) corresponding to the selected magnification ratio, means (42) manifesting the current magnification ratio position of the optical arrangement, means (102) to compare the selected magnification ratio with the current magnification ratio position manifestation, and means (92) responsive to the comparison to change the optical arrangement to the selected magnification ratio.
Claim 2
Dependent Claim 117 words
A reproduction apparatus for producing copies of a document selectively at one of a plurality of copy image magnification ratios including a photosensitive surface (12), a magnification selector (103), and an optical arrangement (36, 38, 40) for projecting images onto the photosensitive surface at a selected magnification, the apparatus being characterised by a control (90) with associated memory (100), means for reading a word from memory (99) corresponding to the selected magnification ratio, means (42) manifesting the current magnification ratio position of the optical arrangement, means (102) to compare the selected magnification ratio with the current magnification ratio position manifestation, and means (92) responsive to the comparison to change the optical arrangement to the selected magnification ratio.
Claim 3
Dependent Claim 34 words
The apparatus of claim 1 wherein the means (42) manifesting the current magnification ratio position includes a potentiometer, and wherein the apparatus includes means (98) for converting the potentiometer voltage to a digital signal.
Claim 4
Dependent Claim 61 words
The apparatus of claim 1 or claim 2 including a motor (41) mechanically connected to an optical element (36 or 40) of the optical arrangement for changing the magnification ratio, and a forward triac and a reverse triac (94, 96) electrically connected to the motor for activating the motor in either the forward or reverse direction in response to said comparison.
Claim 5
Dependent Claim 26 words
The apparatus of claim 3 including means (90, 92) for selectively pulsing the motor upon detecting that the optical element is near the selected magnification ratio.
Claim 6
Dependent Claim 49 words
The apparatus of claim 4 wherein the means (90, 92) for selectively pulsing the motor includes means for determining that the optical element is a given first distance from a selected location defined by the selected magnification ratio, and means for slowing the motor in response to said determination.
Claim 7
Dependent Claim 84 words
The apparatus of claim 5 wherein the means for slowing the motor comprises means for operating the motor at approximately a 70 percent duty cycle upon determining that the optical element is at said first distance, and for operating the motor at approximately a 50 percent duty cycle upon determining that the optical element is at a second distance from the selected location and repeating the process for progressively closer distances and successively lower duty cycles until the optical element reaches the selected distance.
Claim 8
Dependent Claim 40 words
The apparatus of claim 6 including means for determining that the optical element is at a shut off distance from the selected location, stopping the pulsing of the motor, and allowing the optical element to coast to the selected location.

References Cited (Backward Citations)

US3735686A Cited
US3798517A Cited
GB1544269A Cited
US4097786A Cited
DE2909387A1 Cited
FR2438852A1 Cited

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