GB2149268A

GB2149268A - Facsimile apparatus

Info

Publication number: GB2149268A
Application number: GB08426541A
Authority: GB
Inventors: Kestutis E Bliudnikas
Original assignee: Alden Research Foundation
Current assignee: Alden Research Foundation
Priority date: 1983-10-31
Filing date: 1984-10-19
Publication date: 1985-06-05
Also published as: GB8426541D0; JPS60174572A; FR2554297A1; DE3439868A1; CA1206251A

Abstract

Facsimile apparatus for scanning a graphic record R fed along a supporting table T includes a lens system L for projecting an image of the record on a plane. Adjacent the plane is a moving masking belt having crosswise slits 12 and a photobar P with a long narrow, photoresponsive surface 11 at right angles to the mask slits 12. The mask slits 12 and photorespective surface 11 together define successive elemental image areas progressing along the surface stimulating the photobar P to generate a signal series which, when amplified and transmitted reproduce the original record in a recorder. <IMAGE>

Description

SPECIFICATION Improvements in facsimile apparatus The present invention relates to facsimile apparatus.

In facsimile scanning of pictures, alphanumeric text, maps and like graphic records, the record is usually fed lengthwise along a platen or table exposing successive wide transverse linear areas of the record to an optical system for projecting an image of the wide. record area on to a plane. At the plane a narrow line along the wide transverse area is broken up into elemental areas approximately as long in a first elemental dimension along the line as the narrow line is in its second dimension, normal or at right angles to the first dimension. As the record is fed along the table it is thus scanned line by transverse line of elemental width and area by elemental area along each line. The elemental areas are of a size such that electrical signals corresponding to the intensity of light from each area can be used to reproduce the graphic record with fidelity in a facsimile recorder.

There are now available photoelectric devices, known as photobars, which have an elongate photoelectrically responsive surface on which a portion or the whole length of a wide line of the record may be imaged. Such devices have an elongate photoresponsive surface of width narrow enough to define one dimension of an elemental area. It is an object of the present invention to provide improved apparatus for scanning a graphic record.

According to the invention apparatus for scanning successive areas of a graphic record comprises an optical means for projecting an image of the record on a plane; a photoelectric device adjacent the image plane having an elongate photoresponsive surface of width to define one elemental dimension of an elemental area of the image; in combination with a moving mask between the record and the photoelectric device having an elongate aperture effectively at right angles to the elongate photoelectric surface and of width to define the other elemental dimension of an elemental area moving along the surface; whereby the photoelectric device converts the moving elemental image area into an electrical signals series.

The photoelectric device may have an elongate, unitary photodiode surface of width normal to the scanned line to define said one dimension of the elemental area of the image.

In a preferred embodiment the invention provides facsimile apparatus for scanning successive elemental areas of a graphic record line by transverse line and elemental area by area along each line, comprising: a support for the graphic record; means for feeding the record lengthwise along the table; optical means for projecting a transverse image of the record line on an image plane; a photoelectric device beyond the image plane having an elongate, unitary photodiode surface with two output terminals, the surface being of width normal to the scanned line to define the first dimension of an elemental area of the image; and a mask between the table and the image plane for moving along a transverse line of the record image and having an elongate aperture crossing the transverse line of the image, the aperture being of width to define the second dimension of an elemental area lengthwise of the scanned record line; and means to drive the mask and aperture parallel to the line image to define successive elemental image areas along the photoelectric surface, so that the photoelectric device generates corresponding electric signals.

The invention may be understood more readily, and various other features of the invention may become apparent, from consideration of the following description.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing, Fig.

1, which is an exploded, isometric view of facsimile apparatus constructed in accordance with the invention.

Fig. 1 shows schematically a facsimile scanner in which a graphic record R marked with a symbol R" of an arrow is fed along the top of a support table T by opposed feed rolls 1, 2 one of which is turned by a clock motor M1. As it is fed over the table a relatively wide portion of the record R is exposed through an opening 3 in the table to illumination from a conventional light source 4, shown fragmentarily. An optical system represented by the simple lens L projects an image I of the record R on a plane represented by the image, the record R being fed normal to its image. Some light of the image falls on a photobar P, and produces electrical signals at the two output terminals t of the photobar for processing in an amplifier 6 connected to the terminals. The signals are applied through a direct, radio or light transmission line 7 to a facsimile recorder 8.

The photobar may be type RL-1 728H manufactured Reticon Corporation, Sunnyvale, California. It has a substrate 9 supporting an elongate photoresponsive surface 11 of the photodiode type on which a voltage is impressed by the amplifier 6. The width wof the surface 11 is approximately 1 6 microns, and its length is approximately one inch. An image projected on the photodiode surface from a record eight inches wide has one dimension, the width w of an elemental area, defined by the photodiode surface. The second dimension, the length I of the elemental area along the scanned line is defined by one of three apertures or slits 1 2 equally spaced along an endless belt 14 which is orbitted on a path around two guide rolls 1 6 by a drive motor M2.The path of the belt is parallel to the elongate photoelectric surface so that the effective crossing of its moving slit I and the photodiode surface width w defines successive elemental image areas along the surface.

The surface, which is a unitary diode thus converts the light intensity of the successive elemental areas into an electric signal series.

The moving mask aperture 1 2 and the photodiode surface 11 thus cooperate to define a succession of elemental areas progressing along the surface and converting the various light intensities along each elemental line of the record into electrical signals of correspondingly varying amplitude. The mask 14 and photodiode surface 11 should be as close to the plane of the image I as physically practical, the belt mask preferably being before and the photodiode being beyond the image plane.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modification and equivalents which fall within the scope of the appended claims.

Claims

1. Apparatus for scanning successive elemental areas of a graphic record comprising: optical means for projecting an image of the record on a plane; and a photoelectric device adjacent the image plane having an elongate photorespective surface of width to define one elemental dimension of an elemental area of the image; in combination with a moving mask between the record and the photoelectric device having an elongate aperture effectively at right angles to the elongate photoelectric surface and of width to define the other elemental dimension of an elemental area moving along the surface; whereby the photoelectrical device converts the moving elemental image into an electrical signal series.

2. Apparatus according to claim 1 wherein the photoelectric device has an elongate, unitary photodiode surface of width normal to the scanned line to define one dimension of an elemental area of the image.

3. Apparatus according to claim 1 or 2 and further comprising means to drive the mask and aperture past the image plane.

4. Apparatus according to claim 1, 2 or 3 and further comprising means to guide the mask on a path parallel to the elongate photoelectric surface.

5. Apparatus according to any one of claims 1 to 4 wherein the mask is an endless belt having one or more transverse aperture slits.

6. Apparatus according to any one of claims 1 to 5 and further comprising means to support the record, and means to feed the record in a direction normal to the image of the record.

7. Apparatus according to any one of claims 1 to 6 wherein the photoelectric device has output terminals carrying the electrical signals.

8. Apparatus according to claim 7 and further comprising signal amplifying means connected to the terminals.

9. Facsimile apparatus for scanning successive elemental areas of a graphic record line by transverse line and elemental area by area along each line, comprising: a support for the graphic record; means for feeding the record lengthwise along the table; optical; means for projecting a transverse image of the record line on an image plane; a photoelectric device beyond the image plane having an elongate, unitary photodiode surface with two output terminals, the surface being of width normal to the scanned line to define the first dimension of an elemental area of the image; and a mask between the table and the image plane for moving along a transverse line of the record image and having an elongate aperture crossing the transverse line of the image, the aperture being of width to define the second dimension of an elemental area lengthwise of the scanned record line; and means to drive the mask and aperture parallel to the line image to define successive elemental image areas along the photoelectric surface, so that the photoelectric device generates an electric signal series.

1 0. Apparatus substantially as described with reference to, and as illustrated in, the accompanying drawing.