Roll microfilm retrieving method and device therefor

Claim 2

A roll microfilm having a series of picture frames each having a border therearound for use with a microfilm retrieving device of the type having a light source and a plurality of detecting elements, comprising a group of at least three small size marks having optical detection characteristics which may be simulated by dust particles lying on the microfilm, said marks being located within the border of each frame, spacings on either side of an intermediate mark in the lengthwise direction of the microfilm being disparate and corresponding in number and alignment with said detecting elements, whereby erratic activation of said detecting elements by dust particles on said microfilm is inhibited, the relative positions of said marks being invariable in each frame of said roll microfilm, each said group of marks including three small size round marks with each of said round marks having a diameter of about 0.5 to 1.0 millimeters, the border of said picture frames having a dimension of about 1.5 millimeters to 2.0 millimeters.

Claim 3

A roll microfilm having a series of picture frames each having a border extending to an edge of said microfilm, and a group of first and second small optically detectable marks and a third small optically detectable mark intermediate said first and second marks with respect to the lengthwise direction of said microfilm and located within the border of each of said frames, said marks having diameters from 0.5 to 1.0 mm whereby the optically detectable characteristics of said marks may be simulated by the optical characteristics of dust particles which may accidentally come to rest on said microfilm, the spacing between said first and third marks being different than the spacing between said second and third marks in the lengthwise direction of said film, the relative positions of the marks of each frame with respect to each other and with respect to the respective frames being invariable throughout the length of said roll microfilm, whereby the probability of groupings of dust particles on the film duplicating the grouping of said marks is minimized.

Claim 4

A roll microfilm having a series of picture frames each having a border extending to an edge of said microfilm, and a group of first and second small optically detectable marks and a third small optically detectable mark intermediate said first and second marks with respect to the lengthwise direction of said microfilm and located within the border of each of said frames, said marks having diameters from 0.5 to 1.0 mm whereby the optically detectable characteristics of said marks may be simulated by the optical characteristics of dust particles which may accidentally come to rest on said microfilm, the spacing between said first and third marks being different than the spacing between said second and third marks in the lengthwise direction of said film, the relative positions of the marks of each frame with respect to each other and with respect to the respective frames being invariable throughout the length of said roll microfilm, whereby the probability of groupings of dust particles on the film duplicating the grouping of said marks is minimized.

Claim 5

The roll microfilm of claim 2 wherein the marks of said group have dimensions of 0.5 - 1 mm in the longitudinal and transverse directions of said microfilm, the marks of said group in each frame being the only marks in the border of each frame longitudinally aligned with respect to said first, second and third marks.

Claim 6

The roll microfilm of claim 2 wherein said marks are longitudinally aligned in said border adjacent one side of said microfilm.

Claim 7

The roll microfilm of claim 2 wherein at least one of said marks is displaced from another of said marks in a direction transverse of said microfilm.

Claim 8

The roll microfilm of claim 5 wherein said first mark is in a border of a frame adjacent one edge of said microfilm and said second mark is in a border of said frame adjacent to the opposite edge of said roll microfilm.

Claim 9

The roll microfilm of claim 6 wherein said third mark is in a border of said frame between adjacent frames.

Claim 10

The roll microfilm of claim 2 wherein one of said marks is positioned in a border of the respective frame adjacent one edge of said microfilm, another of said marks of each frame is in the border of the respective frame adjacent the opposite edge of said microfilm, and the marks of said group in each frame constitutes the only marks in the border of the respective frame in longitudinal alignment with any of said first, second and third marks.

Claim 11

The roll microfilm of claim 2, wherein said roll microfilm is 35 mm. microfilm, and the borders of said frames between the edges of said frames and the edges of said microfilm are from 1.5 mm to 2.0 mm. in width.