FR2607073A1 - Method for double-sided printing of documents and printer used for implementation thereof - Google Patents

Abstract

Method for printing documents composed by a computer, a memory typewriter or any similar machine, characterised in that it consists in associating with the said machine, which is fitted conventionally with positioning and advancing means for a printing medium 2, two mechanical assemblies each comprising a printing head 3, 4, a printing roll 5, 6, a first electronic circuit card being provided in order simultaneously to control the advance of the medium, the movement of the two printing heads transversely to this medium, and their point-by-point printing function, and a second electronic circuit card, comprising a microprocessor and a memory containing a program (in machine language) for simultaneously managing the said printing heads as a function of the text to be double-sided printed on the said medium.

Description

 The present invention relates to computer peripherals, electronic memory typewriters and similar machines, and it relates more particularly to the printer part of these machines.

 In machines of this kind existing to date, printing devices connected to a computer, or memory typewriters, exclusively allow printing on one side, namely the front, of a document. When you want to print double-sided, it is necessary to stop typing the document, extract it, and turn it over, so as to resume printing, starting at the top of the back of the document already printed on the front.

In the case of continuous tapes, such a two-sided printing is therefore inconceivable.

 The invention eliminates this limitation and makes it possible to simultaneously print double-sided any previously memorized text, with the advantages which ensue therefrom.

 To this end, the system according to the invention combines, in combination, on the one hand the "notion" of duplex on the level of the computer software, this "notion" in turn managing the programming of the advance of paper and the simultaneous movement of two printheads arranged on either side of said paper, and on the other hand of a mechanical assembly for handling the paper, associated with two groups of printheads opposite the level of hard.

 The invention therefore relates, firstly, to a process for printing documents edited by a computer, a memory typewriter or any similar machine, characterized in that it consists in associating with said machine, usually equipped with means for locating and advancing a print medium, two mechanical assemblies each comprising a print head and a print cylinder, a first electronic card being provided for simultaneously controlling the advance of this medium, the displacement two printheads transversely to this support and their point-to-point printing function, and a second electronic card, comprising a microprocessor and a memory containing a program (in machine language) for the simultaneous management of said printheads , depending on the text to be printed on both sides of said support.

The invention is aimed, secondly, at a device intended to be substituted for the usual printing means associated with a computer, a memory typewriter or any similar machine, with a view to carrying out duplex printing on a medium for texts edited by this machine, this device being characterized in that it is composed
- a mechanical assembly comprising the usual means for taking charge of the support and its advance, a first printing group consisting of a printing head and a printing cylinder situated on one side of the support and a second printing group identical to the first and located on the other side of the support,
a first electronic card carrying the means for controlling said mechanical assembly, by simultaneously controlling the advance of the support, the transverse displacements of the two printheads and the point-by-point printing of each of said heads,
- And a second electronic card with microprocessor and memory, containing the program for the simultaneous management of said heads.

 In practice, such a device will be applicable for example to the simultaneous double-sided printing of individual cards, such as administrative documents, or of continuous strips of paper, such as listings.

The resulting advantage is twofold in all cases: firstly, the document is printed in half the time compared to conventional printers. Secondly, the document is generally half as long, which in particular in the case of listings represents a saving of paper, space saving and ease of operation.

We will now describe the invention in more detail with reference to the accompanying drawing on which
- Figure 1 schematically shows the elements of the set of prints according to the invention, seen from the side.

 - Figure 2 shows the detail of the paper detector at the level of the sheet handling mechanisms.

 If we refer first to Figure 1, we see that the printing device according to the invention comprises a paper gripping mechanism designated by the general reference 1, which routes each sheet of paper 2, to two printing units located on either side of the sheet, and each comprising respectively a printing head (3 and 4), cooperating with a cylinder (5 and 6), thus ensuring simultaneous typing on both sides.

 In FIG. 2 we see the detail of the paper detector, integrated into the gripping device 1, and which comprises several photoelectric cells 7 which make it possible to define the width of the paper 2 in order to inform the soft part of the system thereof.

 This set of two printheads 3 and 4 joined on either side of the sheet is controlled by the software of the computer in which the programmer has integrated the "notion" of double-sided which simultaneously manages the advance of said heads and the advance of the paper when the print heads have completed their respective lines, before advance of the paper is possible.

The device according to the invention, thus schematically described, is implemented in accordance with the following procedure
In the case of the application of the process to the electric typewriter, the device will have the following peculiarities
- the introducer + the PIDI system (Internal position of the inserted document ") (Figure 2).

 The introducer is a mechanical device, allowing the introduction of the paper that will be used for printing the document.

 This paper can be ordinary paper, of conventional format, sheet by sheet, in roll or mounted in the form of continuous listing paper, provided with caroll bands, thus bringing its total width to 240mm.

 To detect the presence of the nature of the paper introduced, the introducer is equipped with 4 photoelectric cells 7a, 7b, 7c, 7d, with a very fine resolution, of the order of mm.

 - cells 7b and 7c will indicate the presence of the sheet-by-sheet paper, 210 mm wide.

 - cells 7a and 7d will detect the presence of paper mounted in caroll strips.

 The paper detection system, the information of which has thus been supplied by the photocells, will be the start of a permanent control of the position of the paper circulating inside the machine.

 This system is permanently controlled by the electronic unit, whose information is designated by "P.I.D.I." (Internal position of the document entered).

Before generating this PIDI information, the system will have referred to its memories, in which the different types of formats to be processed are contained, for example - - A4 format = 210mm x 297mm
- Format in 12 "= 210mm x 307mm.

Interpretation
The PIDI = 1 means that the introducer has brought the document paper in position, in front of the head of the Recto, so that the writing of the first line is possible.

 The P.I.D.I. = 40 means that the introducer has placed the paper in front of the Recto head so that writing is possible at the 40th mm.

 The P.I.D.I. is information resulting from the action of a stepping motor, controlled manually, in the case of electric machines, or electronically, in the case of printers and computer peripherals.

 The choice of the stepping motor, which will cause the internal movement of the document, will be done according to the quality chosen of the typewriter, or the printer.

 This stepping motor will be controllable in the forward and reverse direction.

System code according to the invention
The characteristics of the new system codes according to the invention are generated by the machine keyboard or by the
SoftWare, executed by a computer, in the case of a printer.

The codes indicating the different modes are
- in simplex mode
ESC, + ESC, + r = return to RECTO only
ASCII value: CHR 9 (27) + CHR $ (27) + CHR $ (114)
- in Reverse mode
ESC, + ESC, + v = VERSO only
ASCII value: CHR t (27) + CHR $ (27) + CHR $ (118)
- in simultaneous mode:
ESC, + ESC, + s = send simultaneously
ASCII value: CHR S (27) + CHR $ (27) + CHR $ (115)
Additional codes to modify for use
of the system
- FF = Form Feed (end of page) CHR S (12), will become,
FF + mode indicator either
- FF + ESC + ESC + r
- FF + ESC + ESC + v
- FF + ESC + ESC + s
In the case of the typewriter, the data is entered from the keyboard, along with its type and shape.

 Additional function keys will be provided for operating the system.

Examples
RECTO KEY
for entering the document in RECTO
BACK SIDE
for entering the document in VERSO.

 These two function keys will be controlled by a logical operator who will have the function, OR EXCLUSIVE (selection of entry in Front or Back).

 If you choose to edit the document in its input mode (Front or Back), the machine sequentially edits the data contained in its buffer memories (Buffer), in the order chosen by the operator, when input, (we will keep the usual word processing characteristics).

 If you choose to edit simultaneously in Duplex, this mode will be indicated by machine, by pressing a function key provided for this purpose, which will be that of SIMULTANE.

 In this case, the machine will implement its simultaneous editing program, contained in the system's ROM memory.

Principles of operation of the edition in Duplex, simultaneous
Definition of the elements to be implemented and controlled for the realization of the simultaneous edition
1. A writing head in Recto which functions according to the classic mode and which moves in a horizontal direction, in a bi-directional way.

 This printhead is equipped either with needles which form the characters (impact printing) or with a printing wheel (daisy), which form the characters after striking a hammer.

 2. A printhead on the back which has the same characteristics as those on the front, described in the previous paragraph.

3. A paper advance system, used during line feed (Line Feed), page feed (Form
Feed), and at the different positions, front and back of the document.

 The originality of the invention of the method according to the invention lies in the electronic management of the system common to the two printheads.

 Case of a system with a print head in Recto.

 The data coming from the computer, formatted by the character generator, contained in ROM memory in the machine, requests the needles or the daisy, to form and print the characters.

 An inked ribbon, placed between the needles or the daisy, and the paper pressed on the printing cylinder, allows the transfer of the ink, on the paper, to the formation of the characters.

 The print head writes these characters in a print line, and moves from left to right, or from right to left, and line to line, from the beginning of the document to the end of the document.

 The vertical displacement of line in line can be done thanks to the order generated by the system which sends the data, and which is called LF, that is to say: Line Feed.

 In the case of the system according to the invention, the originality is therefore the management of the line feed, common to the two printheads.

 Electronic management of LF s (Line Feed in simultaneous mode, or line feed in simultaneous printing mode).

An electronic card, controlled by a microprocessor, with its memory system, controls and memorizes all orders
LF s, sent by the computer, in the case of a printer, or by the keyboard, in the case of a typewriter.

 I1 stores these L F s and establishes a preferential list as to their triggering and their execution.

 This preferential list is therefore established, taking into account the number of characters per line, preceding each LF, and concerning the documents in Front and Back separately.

 The system according to the invention allows the execution of the LF s only when the last character of the longest line has been printed.

 The system also takes into account the physical offset between the two printheads, and it is conceivable that the printhead in Front is able to execute 5 lines of text, (5 LF) before the head in Back be operational.

 This taking into account is also valid for the end of the document, namely that the end of page of the document in Front occurs at least 5 lines before the end of the document in Back.

 This figure of 5 lines is an estimate, but may vary depending on technology and manufacturing.

 More generally, the example of implementation above is given by way of illustration without any limiting character, and the invention naturally includes all the variants of the process thus defined and of the devices allowing its application.

Claims (4)

1. A method for printing documents edited by a computer, a memory typewriter or any similar machine, characterized in that it consists in associating with said machine, usually equipped with means for locating and advancing d '' a print medium, two mechanical assemblies each comprising a print head and a print cylinder, a first electronic card being provided to simultaneously control the advance of this medium, the displacement of the two print heads transversely by relative to this support and their point-to-point printing function, and a second electronic card, comprising a microprocessor and a memory containing a program (in machine language) for the simultaneous management of said printheads, according to the text to be printed on the front - reverse on said support. 2. Device intended to be associated with a computer, a memory typewriter or any similar machine with a view to carrying out double-sided printing on a medium of the texts edited by this machine, device characterized in that it consists  - a mechanical assembly comprising the usual means for taking charge of the support and its advance, a first printing group consisting of a printing head and a printing cylinder situated on one side of the support and a second group of identical print to the first one and located on the other side of the support,  a first electronic card carrying the means for controlling said mechanical assembly, by simultaneously controlling the advance of the support, the transverse displacements of the two printheads and the point-by-point printing of each of said heads,  - And a second electronic card with microprocessor and memory, containing the program for the simultaneous management of said heads. 3. Device according to claim 2, characterized in that the support is an individual card, such as an administrative document. 4. Device according to claim 2, characterized in that the support is a continuous strip of paper, such as a listing.