Automatic microfilm handling apparatus

Claim 2

In a microfilm handling apparatus for controlling motion of microfilm webs having two parallel tracks of image frames, one track adjacent each edge of the web to position an image frame of said microfilm web in a viewing station, wherein said microfilm web contains optically detectable position markers corresponding to the image frames of each of said two parallel tracks, said apparatus comprising: a. means for controllably driving said web in a given direction of travel along a transport path: b. light detection means for optically detecting said position markers, such that a position signal is produced when a position marker is adjacent said light detection means; and c. web position regulation means controlled by said position signal for stopping the driving means when a said position marker is positioned adjacent said light detection means, the improvement wherein said light detection means comprises two sets of light detectors, a first set for optically detecting position markers corresponding to image frames of a track adjacent one edge of the web and the other set for optically detecting position markers corresponding to image frames of the other track adjacent the opposite edge of the web, each of said sets of light detectors comprising at least three light detectors, two of which are abutting each other and have an effecting sensing diameter at said focal plane which is not greater than one-half the dimension of a position marker parallel to the direction of motion of the web such that two separate detected signals are produced when a position marker is detected, and a third detector for producing a light level reference signal, wherein said web position regulation means further comprises a position signal conditioning network means coupled to the outputs of said detectors of each set detectors for comparing a said light level reference signal and a said detected signal and for producing a position signal only when the difference between said reference signal and said detected signal exceeds a predetermined value to thereby automatically adjust the threshold sensitivity level at which a position signal is produced, and wherein means are provided for sensing the final image frame of one of said two parellel tracks at one end of the web and for providing and end-of-web signal thereupon, means for reversing the direction of travel of said web in response to said end-of-web signal and transverse drive means for shifting the microfilm web transversely with respect to the transport path in response to a said end-of-web signal whereby image frames of either of said two tracks may be positioned in said viewing station.

Claim 3

An apparatus according to claim 1, wherein said position signal conditioning network further comprises variable gain amplifiers coupled to each of said light detectors such that the output of each light detector and amplifier combination may be adjusted to provide optical density selectivity and wherein the outputs from the respective comparing means associated with both light detection means are coupled to provide a single set of compensated position signals.

Claim 4

A microfilm handling apparatus for controlling motion of microfilm webs to position an image frame of said microframe web in a viewing station, wherein said microfilm web contains optically detectable position markers corresponding to the image frames, said apparatus comprising: a. means for positioning and supporting said web in a transport path; b. driving means for controllably driving said web along said transport path; c. viewing station means along said transport path through which light is directed and including a focal plane at which an image frame of said web may be positioned for projection by an optical system; d. light detection means comprising at least one light detector positioned within the viewing station means adjacent said focal plane for optically detecting said position markers, such that a position signal is produced when a position marker is adjacent a light detector; and e. web position regulation means controlled by said position signals which when enabled stops the driving means when a said position marker is positioned over a light detector whereby an image frame is positioned in the viewing station for projection of an image from said frame, the improvement wherein said light detection means comprises an array of three light detectors positioned along a line parallel to said direction of travel, the center detector in said array abutting the other detectors, each light detector having an effective sensing diameter at said focal plane which is not greater than one-half the dimension of a position marker parallel to the direction of travel of said web such that two separate signals are detected by two abutting light detectors and a said light level reference signal is produced by the third light detector when a said position marker is positioned over one of two abutting light detectors and not over the other, and wherein said web position regulation means further comprises a position signal conditioning network means for comparing said light level reference signal with a detected signal from at least one of the other light detetors and for producing a position signal only when the difference between said reference signal and said detected signal exceeds a predetermined value to thereby automatically adjust the threshold sensitivity level at which a position signal is produced, and an automatic centering means for comparing said two position signals and which when enabled produces an automatic centering signal for stopping the driving means when said comparison indicates that a first edge of a said position marker is positioned between said two abutting light detectors, whereby an image frame is centered in the viewing station.

Claim 5

A microfilm handling apparatus for controlling motion of microfilm webs to position an image frame of said microframe web in a viewing station, wherein said microfilm web contains optically detectable position markers corresponding to the image frames, said apparatus comprising: a. means for positioning and supporting said web in a transport path; b. driving means for controllably driving said web along said transport path; c. viewing station means along said transport path through which light is directed and including a focal plane at which an image frame of said web may be positioned for projection by an optical system; d. light detection means comprising at least one light detector positioned within the viewing station means adjacent said focal plane for optically detecting said position markers, such that a position signal is produced when a position marker is adjacent a light detector; and e. web position regulation means controlled by said position signals which when enabled stops the driving means when a said position marker is positioned over a light detector whereby an image frame is positioned in the viewing station for projection of an image from said frame, the improvement wherein said light detection means comprises an array of three light detectors positioned along a line parallel to said direction of travel, the center detector in said array abutting the other detectors, each light detector having an effective sensing diameter at said focal plane which is not greater than one-half the dimension of a position marker parallel to the direction of travel of said web such that two separate signals are detected by two abutting light detectors and a said light level reference signal is produced by the third light detector when a said position marker is positioned over one of two abutting light detectors and not over the other, and wherein said web position regulation means further comprises a position signal conditioning network means for comparing said light level reference signal with a detected signal from at least one of the other light detetors and for producing a position signal only when the difference between said reference signal and said detected signal exceeds a predetermined value to thereby automatically adjust the threshold sensitivity level at which a position signal is produced, and an automatic centering means for comparing said two position signals and which when enabled produces an automatic centering signal for stopping the driving means when said comparison indicates that a first edge of a said position marker is positioned between said two abutting light detectors, whereby an image frame is centered in the viewing station.

Claim 6

An apparatus according to claim 3 wherein sid light detection means comprises an integrated array of three photo diodes formed of a homogeneous slab of a photoconducting semiconductor, a common contact on one side of said slab and three discrete transparent contacts positioned along a line on a side of said homogeneous slab opposite that of the common contact.

Claim 7

A microfilm handling apparatus for controlling motion of microfilm webs to position an image frame of said microfilm web in a viewing station, wherein said microfilm web contains optically detectable position markers corresponding to the image frames, said apparatus comprising: a. means for positioning and supporting said web in a transport path; b. driving means for controllably driving said web in a given direction of travel along said transport path; c. viewing station means along said transport path through which light is directed and including a focal plane at which an image frame of said web may be positioned for projection of an optical system; d. light detection means comprising at least one light detector positioned within the viewing station means adjacent said focal plane for optically detecting said position markers, such that a position signal is produced when a position marker is adjacnt a light detector; and e. web position regulation means controlled by said position signals which when enabled stops the driving means when a said position marker is positioned over a light detector, the improvement wherein said light detection means includes another light detector for producing a light level reference signal when a said position marker is not positioned over said another light detector, all said light detectors being positioned along a line parallel to said direction of travel, said web position regulation means further comprises a position signal conditioning network means for comparing said light level reference signal with a detected signal from said at least one light detector and for producing a position signal only when the difference between said reference signal and said detected signal exceeds a predetermined value to thereby automatically adjust the threshold sensitivity level at which a position signal is produced, control means for providing a control signal corresponding to web position and to a desired web transport speed and direction of travel, sensing means for sensing actual web speed and direction, for providing a web motion signal which varies in accordance with web speed and direction of travel, for detecting the final image at one end of said web and for providing an end-of-web signal thereupon, comparing means coupled to the control means and to the sensing means for receiving said control signal and said web motion signal, and for providing an error signal indicative of the difference therebetween and power supply means controlled by said error signal and electrically connected to the driving means for producing web motion in accordance with said error signal, whereby the speed and direction of said web is controlled to position an image frame at the viewing station for projection of an image from said frame, and wherein the apparatus further comprises means coupled to said driving means for reversing the direction of travel of said web in response to a said end-of-web signal and transverse drive means coupled to said sensing means for shifting the microfilm web transversely with respect to the transport path in response to a said end-of-web signal, whereby microfilm webs having parallel tracks of consecutive image frames may be automatically and controllably positioned to thereby position a given image frame on either track in said viewing station.

Claim 8

A microfilm handling apparatus for controlling motion of microfilm webs to position an image frame of said microfilm web in a viewing station, wherein said microfilm web contains optically detectable position markers corresponding to the image frames, said apparatus comprising: a. means for positioning and supporting said web in a transport path; b. driving means for controllably driving said web in a given direction of travel along said transport path; c. viewing station means along said transport path through which light is directed and including a focal plane at which an image frame of said web may be positioned for projection of an optical system; d. light detection means comprising at least one light detector positioned within the viewing station means adjacent said focal plane for optically detecting said position markers, such that a position signal is produced when a position marker is adjacnt a light detector; and e. web position regulation means controlled by said position signals which when enabled stops the driving means when a said position marker is positioned over a light detector, the improvement wherein said light detection means includes another light detector for producing a light level reference signal when a said position marker is not positioned over said another light detector, all said light detectors being positioned along a line parallel to said direction of travel, said web position regulation means further comprises a position signal conditioning network means for comparing said light level reference signal with a detected signal from said at least one light detector and for producing a position signal only when the difference between said reference signal and said detected signal exceeds a predetermined value to thereby automatically adjust the threshold sensitivity level at which a position signal is produced, control means for providing a control signal corresponding to web position and to a desired web transport speed and direction of travel, sensing means for sensing actual web speed and direction, for providing a web motion signal which varies in accordance with web speed and direction of travel, for detecting the final image at one end of said web and for providing an end-of-web signal thereupon, comparing means coupled to the control means and to the sensing means for receiving said control signal and said web motion signal, and for providing an error signal indicative of the difference therebetween and power supply means controlled by said error signal and electrically connected to the driving means for producing web motion in accordance with said error signal, whereby the speed and direction of said web is controlled to position an image frame at the viewing station for projection of an image from said frame, and wherein the apparatus further comprises means coupled to said driving means for reversing the direction of travel of said web in response to a said end-of-web signal and transverse drive means coupled to said sensing means for shifting the microfilm web transversely with respect to the transport path in response to a said end-of-web signal, whereby microfilm webs having parallel tracks of consecutive image frames may be automatically and controllably positioned to thereby position a given image frame on either track in said viewing station.

Claim 9

An apparatus according to claim 5, further comprising means responsive to a manual input signal for causing said transverse web movement and wherein said control means further comprises means responsive to an input reference signal for redetermining the position of said web following a said transverse web movement to thereby provide a corrected control signal.

Claim 10

A microfilm handling apparatus for controlling motion of microfilm webs to position an image frame of said microfilm web in a viewing station, said apparatus comprising: a. means for positioning and supporting said web in a transport path; b. driving means for controllably driving said web in a given direction of travel along said transport path; c. viewing station means along said transport path through which light is directed and including a focal plane at which an image frame of said web may be positioned for projection by an optical system; d. control means for providing a control signal corresponding to web position and to a desired web transport speed and direction of travel; e. sensing means for sensing actual web speed and direction and for providing a web motion signal which varies in accordance with web position, speed and direction of travel; f. comparing means coupled to the control means and to the sensing means for sensing the difference between said control signal and said web motion signal, and for providing an error signal indicative of said difference; and g. power supply means controlled by said error signal and electrically connected to the driving means to produce web motion in accordance with said error signal, whereby the speed and direction of said web is controlled to position an image frame at the viewing station; wherein the sensing mens further comprises means for detecting the final image frame at one end of said web and for providing an end-of-web signal, and wherein said apparatus further comprises means coupled to said driving means for reversing the direction of travel of said web in response to a said end-of-web signal and transverse drive means coupled to said sensing means for shifting the microfilm web transversely with respect to the transport path in response to a said end-of-web signal, whereby microfilm webs having parallel tracks of consecutive image frames may be automatically and controllably positioned to thereby position a given image frame on either track in said viewing station.

Claim 11

A microfilm handling apparatus for controlling motion of microfilm webs to position an image frame of said microfilm web in a viewing station, said apparatus comprising: a. means for positioning and supporting said web in a transport path; b. driving means for controllably driving said web in a given direction of travel along said transport path; c. viewing station means along said transport path through which light is directed and including a focal plane at which an image frame of said web may be positioned for projection by an optical system; d. control means for providing a control signal corresponding to web position and to a desired web transport speed and direction of travel; e. sensing means for sensing actual web speed and direction and for providing a web motion signal which varies in accordance with web position, speed and direction of travel; f. comparing means coupled to the control means and to the sensing means for sensing the difference between said control signal and said web motion signal, and for providing an error signal indicative of said difference; and g. power supply means controlled by said error signal and electrically connected to the driving means to produce web motion in accordance with said error signal, whereby the speed and direction of said web is controlled to position an image frame at the viewing station; wherein the sensing mens further comprises means for detecting the final image frame at one end of said web and for providing an end-of-web signal, and wherein said apparatus further comprises means coupled to said driving means for reversing the direction of travel of said web in response to a said end-of-web signal and transverse drive means coupled to said sensing means for shifting the microfilm web transversely with respect to the transport path in response to a said end-of-web signal, whereby microfilm webs having parallel tracks of consecutive image frames may be automatically and controllably positioned to thereby position a given image frame on either track in said viewing station.

Claim 12

An apparatus according to claim 7, further comprising means responsive to a manual input signal for causing said transverse web movement and wherein said control means further comprises means responsive to an input reference signal for redetermining the position of said web following a said transverse web movement to thereby provide a corrected control signal.