GB2198009A

GB2198009A - Converting data for facsimile transmission

Info

Publication number: GB2198009A
Application number: GB08722041A
Authority: GB
Inventors: Richard Mark Charles
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-09-19
Filing date: 1987-09-18
Publication date: 1988-06-02
Also published as: GB8722041D0; GB8622607D0

Abstract

A facsimile apparatus includes a web carrier 12, a head carrier 14 which, in use, is reciprocated across a web 10 on web carrier 12, and a preferably detachable data conversion assembly 18 including a read head 24 carried by the head carrier 14 so that it can scan the web 10 and provide an output signal representing data on the web 10. A clock signal may be provided, preferably by a fixed scale 28 read by a reading head 26 that moves with the data conversion assembly 18. The signals may be passed through an interface assembly to a computer memory for storage and subsequent high-speed transmission via a modem and a telephone line. The head carrier 14 may also include a print head for printing data via the modem and computer memory and the conversion assembly 18 may be adapted to convert a standard computer printer for document reading. <IMAGE>

Description

CONVERTING DATA FOR FACSIMILE TRANSMISSION The present invention relates to an apparatus usable in converting visibly recorded data (such as print, writing or graphics) to a machine-handleable form, e.g. for facsimile transmission. It particularly relates to apparatus for converting a printer to a data converter, and to facsimile transmission apparatus comprising such a converted printer. In another aspect, it relates to a versatile webhandling system, capable in a first mode of printing on a web, and capable in a second mode of converting data visibly recorded on a web.

A known type of web-handling system comprises a head carrier, a web carrier, and means for effecting relative displacement of the head and web carriers so that a head can scan a web carried by the web carrier. This is exemplified by a computer printer, in which a printing head is moved relative to a web (generally both head and web being moved) so that it scans a pattern of lines of possible print. In one aspect, the present invention provides a data conversion assembly comprising a read head member mountable (preferably detachably) to a head carrier of such a web handling system so that a web is scannable thereby; the read head member having means for detecting visible data moved relative thereto and providing an output signal. The data conversion assembly preferably also includes means for providing a clock signal related to the scanning displacement.If the scanning motion is very accurately controlled, this may be a time signal. But generally it is preferable to employ means for detectinq the displacement. Thus there may be a fixed scale, and a scale reading head displaceable with a head carrier.

The read head member may be connectable to the printing head carrier of a standard computer printer. The output signal or signals from the head member (e.g. comprising a first signal from the head that detects visible data, and a second signal from a scale reading head) may be fed to an interface assembly which converts them to suitable form for feeding to a computer for storage on a disc. Thus data from a web (e.g. a printed sheet) can be converted into electrical signals at a speed determined by the operation of the web handling system (which may be relatively low), and the data can be accumulated in the memory of a computer (and may be checked if desired), and it may subsequently be transmitted at a high speed, e.g. over a telephone line via a modem.

The web carrier may be a standard dot-matrix printer for a computer. The combination of a printer and a computer, particularly when the printer is designed to produce graphics, generally has different modes of operation which differ in the number of scans in the X direction which occur for unit displacement in the Y direction. For use in data conversion, 128 or 256 scans in the X direction per inch, displacement in the Y direction may be suitable. (Of course the Y displacement is stepwise, between scans).

An embodiment of the invention will now be described in greater detail, with reference to the accompanying drawings, in which: Fig. 1 is a schematic view of a read head member mounted to a head carrier of a printer; and Fig. 2 is a schematic block diagram of the electronic circuitry.

The illustrated embodiment is used in conjunction with (or, in another aspect, comprises) a dot-matrix printer (in a specific example, an Amstrad PCW 8256 printer) linked to a computer. The printer includes means for indexing a web of paper 10, here shown schematically as a roller 12. A printing head 14 is mounted adjacent the roller 12, and in use it scans to and fro in the longitudinal direction of the roller 12 (i.e. out of and into the plane of the paper). A lid member 16 is releasably engaged. To adapt this printer for data conversion, a read head member 18 has been releasably mounted on the print head 14, so as to travel with it. The read head member 18 has a lower framework 20 which is adapted to engage over the print head 14 clampingly.An L-shaped arm member 22 is hingedly connected to the rear of the framework 20, and extends outwardly and forwardly beyond the print head 14 so as to overlie the roller 12. Resilient means (not shown) urge it to pivot forwardly and downwardly. At its outer end region, it carriers a data read head 24. This is a well-known item, as used on the light pens used for reading bar codes. That is, it has means for emitting a narrow pencil of radiation, and a means for detecting reflected radiation. In use, it is urged into contact with the paper web 10 on top of the roller 12.

The framework 20 also carries a read head 26. This faces a graticule 28 (a long strip of alternating narrow black and white lines), which in this example is mounted on the inside of the cover 16.

Thus, in use, the printer indexes the web 10 and scans the print head 14 in the normal way, the indexing not being in line width steps, but in the much smaller steps appropriate to drawing graphics. Generally, the print head will not be effecting printing, but will merely be serving as a carrier for the read head member. During each scan, the data read head 24 detects a succession of black and white portions of the web 10 corresponding to data recorded on it at that location (in the Y direction) and, simultaneously, the graticule read head 26 reads the graticule 28 and thereby produces an alternating signal which will be completely regular (assuming the graticule to be regular) if the print head 14 travels with uniform velocity; and which in any case, provides a measure of the travel of the head 14.

The outputs of the two read heads 24,26 are processed by interfacing circuitry. This may take many forms, and one will be described. The signal from the graticule read head 26 is used as a clock signal. Every time a change from black to white or from white to black is detected thereby, the state of the output of the print read head is determined, and stored in a memory. Thus after the print head 14 has made one scan across the web 10, a large number of pieces of data corresponding to the black/white state of the web at all of the sampling positions are recorded in a memory. At the end of the scan, the data may be down-loaded from this memory to a host computer, where they may be stored on a disc and optionally displayed on a screen.

The interface circuitry is shown in schematic terms in Fig. 2. Data from the print read head 24 are fed along line 50 to a "serial in/parallel out" device 52. This also receives a clock signal provided by means of the graticule read head 26, via line 54. The data are thus divided into eight bits, and fed to a memory 56. This also receives clock signals from the graticule read head, firstly via a divider chain 57 and an AND gate 58, and secondly via the divider chain and a counter 60. The effect of this is that each successive group'of eight bits of data are fed to the next location of the memory 56. After a scan has been completed, the computer accesses the memory, gives a reset signal to the interface circuitry, and instructs the print head 14 to perform another scan.

Facsimile data in the computer memory can be transmitted over a telephone line via a modem. Likewise data can be received in the memory via the modem. It can then be displayed on a screen and/or printed out.

In a modified form of embodiment, the read head member has a multiplicity of read head elements thus enabling more data to be scanned as the head is moved across the page and also enabling some of the elements to be assigned to scanning the "clock track" graticule.

Claims

CLAIMS:

1. A web handling system comprising a head carrier; a web carrier; means for effecting relative displacement of the head and web carriers so that a head can scan a web carried by the web carrier; and a data conversion assembly comprising a read head member mounted or mountable to said head carrier so that a web is scannable thereby; the read head member having means for detecting visible data moved relative thereto and providing an output signal.

2. A web handling system according to claim 1 further including a printing head mounted or mountable to the head carrier so that the system is usable as a printer.

3. A web handling system according to claim 1 or claim 2 wherein the data conversion assembly includes means for providing a clock signal related to the scanning displacement.

4. A web handling system according to claim 3 wherein said clock signal is provided by a timer.

5. A web handling system according to claim 3 wherein said clock signal is provided by displacement measuring means.

6. A web handling system according to claim 5 wherein said displacement measuring means comprises a fixed scale, and a scale reading head displaceable with a head carrier.

7. A web handling system according to any preceding claim including an interface assembly for converting an output signal or signals from the head member to suitable form for feeding to a computer for storage on a disc.

8. A web handling system substantially as herein described with reference to and as illustrated in the accompanying drawing.

9. A data conversion assembly adapted to be mounted to a head carrier of a web handling system which also includes a web carrier and means for effecting relative displacement of the head and web carriers so that a head can scan a web carried by the web carrier so as to convert the web handling system to a system according to any of claims 1 to 8.