In particular, the invention is related to a method wherein one or more additional processes are performed on the printed image, such as a cutting operation, or a second printing step.

State of the art [0002] After printing, a part of the printed image may need to be cut along a predefined cutting path, or a second printing step may need to be undertaken, superimposed on the previously printed image.

[0003] Current technology allows to enter a sheet or a roll of printed paper into a cutter or a second printer, enter manually information about the cutting or re-printing path, and perform the cutting or second printing operation.

[0004] The inventors of the present invention have published information about a technique for printing and subsequent cutting, in the Press Release entitled Mutoh launches new range of signcutting plotters', September 17, 2002, published in Sign Update Nov/Dec 2002, ESM (European Sign Magazine) Oct/Nov 2002 and Sign Directions Issue 53 Sept/Oct. 2002. According to this technique, a reference frame is used as a registration mark, in order to allow a friction feed cutting plotter to automatically detect the

reference box/frame size & position. The image is printed inside such a reference frame, which is basically a rectangular box with a given line thickness, surrounding the printed image. The cutter, through use of a laser based optical sensor, detects the presence of this frame, and measures the dimensions and position of the frame. An operator then launches the cutting operation on the basis of a source file of printing and cutting data relevant to the image in the detected frame, said data being stored on a computer, which equally calculates the necessary transformation to a given image, to which this image needs to be subjected so that the cutter can perform the cutting operation without errors due to any deformation of the printed image.

[0005] The essential drawback to this system is the need for manual intervention for the identification of the image present inside the detected frame. In the existing system, the cutter will have to be provided manually with a given data file, before the cutting operation can start.

For example, when a random sequence of images has been printed on a roll of paper, the roll is entered into the cutter, and an operator needs to supervise the transmission to the cutter of the right print and cut data, for every image on the roll. Therefore, even though the registration of a printed image takes place automatically through the detection of the reference frame, it is still impossible to print and cut a random series of designs, without supervision.

Aims of the invention [0006] The present invention aims to provide a method and a system which can automatically read the cutting or re-printing information from the inserted media.

Summary of the invention [0007] The present invention is related to a method, a system and a computer program such as described in the appended claims.

Short description of the drawings [0008] Fig. 1 represents a schematic overview of a system for performing the method of the invention.

[0009] Fig. 2 represents a view of one complete image, comprising a reference frame, an image and two barcodes.

[0010] Fig. 3 represents a view of a roll of paper comprising several images, to be treated according to the method of the invention.

[0011] Fig. 4 illustrates the mapping from the theoretical vector space to the printed area.

[0012] Fig. 5 illustrates the embodiment wherein the reference frame is subdivided into a number of segments.

[0013] Fig. 6 illustrates the detection steps of the multiple segments of fig. 5.

[0014] Fig. 7 illustrates the detection of a single reference point.

Detailed description of the invention [0015] The present invention is related to a method for printing an image, followed by one or more further operations, either printing on top of parts of said images, or cutting out a part of said image along a pre-defined cutting path, or other.

The method is performed by a system comprising at least (see fig. 1) : - a printing/plotting device 1,

- a second device 2, for example for printing or cutting, - a computer 3, coupled to both said devices 1 and 2.

[0016] A software tool according to the invention runs on the computer 3, and governs the method of the invention, as described hereafter. In the following, a job'is defined as a sequence of operations, the first of which is the operation of printing an image by device 1.

The initial printing step is performed on the basis of an image file, such as a bitmap, created for example by a known design software.

[0017] According to the invention (see fig. 2 & 3), an image 4 is printed on a carrier 5, for example a roll of paper, and a number of features are added to the image per se : - a reference frame 6, i. e. a preferably rectangular box, drawn around the image, - at least one identifier 7a and/or 7b : this is preferably a bar code, such as a UPC code or a postnet code, readable by a suitable reading device. In the preferred embodiment, two mutually identical identifiers 7a and 7b are printed in the frame, one at the bottom and one at the top, so that the second operation may be performed regardless of the insertion direction of the carrier into the second device 2. The identifiers are preferably equally placed in the corner. The identifying elements are printed in the vicinity of the image 4, preferably in the vicinity of the frame 6, more preferably inside said frame.

[0018] After the initial printing step of one image on a sheet or a series of images on a roll of paper, the carrier is inserted into the second device 2, for example a cutter. Meanwhile, the invention's software has generated a job specific file for every image. This file is uniquely

defined by its name or an ID tag embedded in the data, and by which the file is linked to the identifier 7. This means that reading the identifier, for example scanning the barcode, allows to identify the ID tag and thus the job specific file. This file comprises the data or a link to the source data of the job which is stored on the computer 3 : bitmap data of the printed image, coordinates of the reference frame, information about subsequent operations in the job (e. g. vector path for a cutting operation).

[0019] A communication sequence now starts between the computer 3 and the second device 2. This sequence comprises the following steps : - the second device 2 detects the position of the reference box 6, - the second device detects and reads the identifier 7a or 7b, to obtain the ID tag relevant to the printed image 4, - the second device sends a message to the computer 3, said message comprising the ID tag, - the relevant source data stored in the computer is identified and output data is sent to the second device, - the second device performs the second operation, on the basis of said output data.

[0020] The output data may comprise the source data, supplemented by additional data, for example data relevant to the orientation of the image and/or the transformation which is to be applied to the image due to scaling or a deformation during printing. The transformation matrix may be calculated by the central computer, or by a processing means present in the second device 2.

[0021] The second device may be a second printer/plotter, for example when the first printing operation is a white ink or coating printing onto a non-

white carrier. Then this first printing step may be followed by a normal inkjet printing step on another printer on top of the white layer. Possibly, this second operation may be followed by a third, for example a position-related lamination, performed through the same sequence of steps described above. In between these operations, process steps may be performed which are unrelated to the image or the position of the reference frame, for example a position-unrelated lamination step.

[0022] Preferably, the identifiers 7 are barcodes, which are read by the same laser based sensor already used in the art to detect the reference frame. Alternatively, the barcode may be scanned by a separate scanner, possibly even a hand-held scanner. Whatever the case may be, the scanning of the identifier reveals the ID tag of the relevant source data, comprising the necessary input to the operation which is to be performed by the second device 2.

[0023] The following describes in detail the way in which the above steps are performed in the exemplary case of a method comprising an initial printing step, yielding an image with reference frame and barcodes, as shown in figure 2, followed by cutting out the image by a friction feed cutting plotter.

- First, the position of the lower corners 10 and 11 is determined by the optical sensor present in the cutting head of the cutter. The corners are found by detecting the position of the vertical sides at two points, for example points 12 and 13, and the position of the lower side at two points, for example points 14 and 15. This allows to scan the barcode 7a along a direction parallel to the lower side. These steps are necessary in case the frame is slightly deformed or tilted.

- Then the barcode 7a is scanned and read,

The cutter detects whether or not the barcode has been read in its normal position, or rotated over 180°. This capability of detecting whether the code has been read from left-to-right or vice versa is a known feature of bar code detection systems. If the barcode is rotated, this means that the sheet or roll of paper has been inserted the other way round, i. e. not the code 7a at the bottom has been detected, but the code 7b at the top. This is the reason why according to the preferred embodiment, two barcodes 7a and 7b are present on each image, so that the direction in which a roll of images is inserted in the cutter, is of no importance. The cutting operation will be adapted to the orientation of the image. Of course, the invention equally covers a method wherein only one barcode is used, and which requires the roll to be inserted in one particular direction.

The cutter links the specific barcode to an ID tag, and sends a message to the computer to look up the matching vector file, This file is then sent to the cutter, From this file, the dimensions of the non-deformed frame are read, allowing a measurement of the actual printed box dimensions, taking into account scaling of the box, rotation, skew or other types of deformation. The measurement involves the detection of the corner points P1'to P4'of the frame, see figure 4. The non-deformed frame dimensions are derived from the vector file, defined by points PI and P2.

After that, the mapping from the effective measured printout coordinate system (bottom part of fig. 4) to the theoretical vector space (top part of fig. 4) is calculated, by a transformation calculation, known in

the art. This transformation is applied by the cutter to the theoretical vector data which is stored in the file. According to the preferred embodiment, this calculation is performed by the cutter itself, not by the central computer, - Finally, the transformed path is cut out.

[0024] It is to be noted that several steps of the above described process are known in the art. For example the measurement of the reference frame dimensions and the calculation of the transformation. Parts of the communication between the cutter and the computer may also take place in a way which is known in the art.

Characteristic to the method of the invention is the so- called RADAR'functionality, which is similar to the operation of plug and play'devices, and defined by the following : - In the background, the computer 3 continuously listens to the connected devices ("server"principle).

- Once the ID is scanned and recognized, it is automatically sent to the computer.

- As the computer receives the ID, the software will start searching for the matching data and eventually send it to the second stage device. If matching data is not found, the user is informed.

[0025] In general, the new and inventive concept of the present invention lies in the fact that an identifier is added to the image, and subsequently read by another device, allowing automatic identification of a particular job. The operations taking place after the computer has sent the necessary output data to the cutter, may be performed according to the method already known and documented. The difference is that according to the invention, it is not an operator who manually transmits the

output data to the second device, but it is this device itself which detects the ID of the job, and requests automatic transmittal of the output data.

[0026] In the case of a roll comprising several images, as shown in figure 3, the cutter can move to the next job, detecting automatically the next image, for example by detecting the lower side of the next frame.

This way, the cutter can cut out vector trajectories for all printed images on a roll, until the end of the roll is detected.

[0027] Figure 5 shows a further embodiment of the method of the invention, wherein the reference frame 20 is not a full rectangle but comprises segments 21. The short sides 22 of the frame are still printed in full, as are the top and bottom sections 23 of the side lines, drawn in the feed direction of the printer. These sections 23 need to be sufficiently long for the laser to detect the points 12 and 13 (fig. 2). In between sections 23, the side lines are drawn as dotted lines. In figure 5, the dots are formed by short lines 24, at a given distance from each other. Each pair of corresponding dots on either side of the frame indicates the end of a segment, as well as the borderline between neighbouring segments. According to this embodiment, the second operation, e. g. a cutting operation, is performed in sequence in each of the segments 21.

[0028] When a reference frame as shown in figure 5 is to be used, i. e. with dotted side lines, the position of the dots 24 can be chosen automatically or manually. In the latter case, the segmentation may be adapted to the printed image. The vector file related to the image as a whole is divided into subfiles, which are all linked to a single barcode, but which otherwise have all the characteristics of a vector file described above. The

sequence of steps described above for the full frame are then applied to each segment, wherein of course the step of detecting and reading the bar code 7 takes place only once at the beginning of the job. The measurement of the position and size of each segment is performed separately for every segment, through laser detection of the dots 24, illustrated in figure 6. The numbers 1 through 21 in figure 6 indicate a sequence of detection steps.

[0029] In figure 7 is described how a single reference point is measured. The reference point is the middle point of the rectangle formed by the dot 24 The middle point is determined by 5 scan moves, which deliver 6 points PI to P6. Firstly, points P1 and P2 are measured in one scan move Ml. The middle of PI and P2 is taken (P12) to start scan moves M2 and M3 and measure P3 and P4. The middle of P3 and P12 is calculated to start scan move M4 and M5 and measure P5 and P6. The middle of P3 and P4, P34 is taken, as well as the middle of P5 and P6, P56. Now the middle point of the rectangle, Pref is calculated by the perpendicular projection of P34 on the line defined by P56 and P12.

[0030] Before every segment is cut or printed on by the second device, said device measures the complete segment (P12, P13, P21 and P22, fig. 5) and sets the transformation matrix. Segments are processed (cut or re- printed) one by one.

[0031] The advantage of this segmented approach is that tracking errors can be reduced due to the fact that feed movements over large distances, for example for the detection of the corner points, can be avoided. The second advantage is better control of the print deformation of long print jobs.

[0032] The invention is equally related to any system able to perform the method of the invention. One

embodiment of such a system is shown in figure 1, even though it may take on other forms. For example, more than two devices might be coupled to the computer 3, for performing a series of consecutive operations. The devices might be coupled to several computers linked together in a network. The second and third devices are equipped with a means for reading the identifying elements. As described above, this preferably takes on the form of a laser based sensor, able to detect the frame 6 and to read the barcodes 7. The device 2 needs to be able to communicate with the computer 3 and needs to be equipped with a means for doing this. The same is true for the computer, which is equipped with a means for communicating with the second device.

[0033] The invention is equally related to the software which is to be run on the computer 3, for governing the method of the invention.