Method, control module and system for imaging a mask layer

Abstract

A method for imaging a mask layer is disclosed, comprising the steps of: providing a mask layer; receiving an image file comprising imaging pixels and non-imaging pixels of a first resolution R1; generating, based on the image file, a modified image file comprising reduced resolution imaging pixels and reduced resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, where the second pitch P2 corresponds to the second resolution R2; based on the modified image file, the mask layer is imaged such that the imaged point has a maximum size less than (square root of 2 * P2), preferably less than P2.

Description

Technical Field

[0001] The field of the invention relates to methods, control modules and computer programs for imaging and controlling the imaging of mask layers, in particular of printing plate precursors. The field of the invention further relates to systems for processing relief precursors, in particular printing plate precursors and more in particular flexographic printing plate precursors or letterpress printing plate precursors. Background Art

[0002] Flexographic printing or letterpress printing is a technique commonly used for mass printing. A flexographic or letterpress printing plate is a relief plate with image elements raised above non-image elements in order to produce an image on a recording medium such as paper, paperboard, film, foil, laminate, etc. Also, cylindrical printing plates or sleeves may be used.

[0003] There are various methods for making flexographic or letterpress printing plate precursors. According to the conventional methods, a flexographic or letterpress printing plate precursor is made of a multilayer substrate comprising a backing layer and one or more photocurable layers. These photocurable layers are imaged by exposure to electromagnetic radiation via a mask layer containing the image information, or by direct and selective exposure to light, in order to obtain a relief printing plate.

[0004] In flexographic or letterpress printing, ink is transferred from the plate to the print medium. More specifically, the ink is transferred to the relief portion of the plate, but not to the non-relief portion. During printing, the ink on the relief portion is transferred to the print medium. Grayscale images are usually created using halftones (for example, using a screening pattern). For a plate printed in a specific color, grayscale means the amount of color reproduced. For example, a printing plate can include different halftone dot areas to print with different densities in these areas. In order to increase the amount of ink transferred and increase the so-called ink density on the substrate, additional very fine structures are applied to the surface of the printed area (i.e., to the relief area). This surface screening is usually obtained by adding a fine structure to a raster image file and then transferring it to a corresponding mask for exposure.

[0005] WO2021110831A1 in the name of the applicant is Figure 1 A to Figure 1 An example of a prior art method for manufacturing a relief printing plate is described in E. Figure 1 A shows the content of a raster image file having an image file resolution corresponding to a pixel size p (corresponding to pitch) of, for example, 6.35 microns. The image file resolution may be, for example, 4000 dpi (=25400*1 / p (in microns)). Next, use Figure 1 B. The surface screen pattern is applied to image area 1, thereby producing Figure 1The modified raster image file shown in C. Figure 1 As shown in C, the generated image area 1' contains fewer pixels 4' to be printed, and the pixels 4' to be printed are located at a distance d from each other. Figure 1 C, a mask is prepared. More specifically, for each pixel 4' to be printed, a hole or transparent area 5 is arranged in the mask. This can be done using a beam of electromagnetic radiation. Figure 1 As shown in D, such a beam will generate an aperture 2 which is larger than the size of the pixel 4 ′, here a circular aperture 2 . Figure 1 The image produced on the mask is shown in E. Therefore, according to Figure 1 A to Figure 1 The method illustrated in E calculates surface screening by changing an original raster image file (e.g., a tiff file) using software (typically raster image processing technology), wherein a file with a larger size is typically generated due to the manipulation. WO2021110831A1 also discloses an improved method for processing a raster image file, comprising the following steps: receiving a raster image file including image data for a plurality of pixels; analyzing the image data of the raster image file; determining control data based on the analyzed image data, and optionally determining at least one new raster image file, wherein the control data is data for controlling the settings of an imaging device so as to change the physical properties of the generated imaging features corresponding to one or more of the plurality of pixels; outputting the raster image file and / or the new raster image file together with the control data to an imaging device for imaging a relief precursor. In this way, the image quality can be improved. For example, depending on whether the image data includes text and / or photos and / or barcodes and / or large continuous areas, etc., the imaging can be controlled in different ways. Summary of the invention

[0006] It is an object of embodiments of the present invention to provide a method, a control module and a computer program which can improve the quality of an image in an even more robust and simplified manner, in particular when the image comprises one or more solid areas.

[0007] According to a first aspect, a method for imaging a mask layer is provided. The method comprises the following steps: providing a mask layer; receiving an image file comprising imaging pixels and non-imaging pixels of a first resolution R1; based on the image file, generating a modified image file comprising imaging pixels with a reduced resolution of a second resolution R2 lower than the first resolution R1 and non-imaging pixels with a reduced resolution, wherein a second pitch P2 corresponds to the second resolution R2; based on the modified image file, imaging the mask layer so that the imaged dots have a maximum size smaller than (√2*P2), preferably smaller than P2.

[0008] Embodiments of the present invention are based on the following creative insight: by first reducing the resolution of the image file and then selecting appropriate imaging settings so that the imaged points do not completely overlap, a fine surface structure can be obtained in a simplified manner without the need for complex manipulation of the image file. This will result in good image quality, especially when the image file contains one or more solid areas. In fact, by using a suitable reduced resolution in the solid area, a suitable surface structure can be obtained on the corresponding solid printing relief of the printing plate, and the ink on the solid printing relief will be more evenly distributed. It can be seen from this that the trailing edge gap can be greatly reduced. In fact, a channel will be generated in the upper surface of the solid relief so that when printing, the resulting printing relief does not contact the substrate over too large an area.

[0009] According to a second aspect, a method for imaging a mask layer is provided. The method comprises the following steps: providing a mask layer; receiving an image file comprising imaging pixels and non-imaging pixels of a first resolution R1; based on the image file, generating signals corresponding to imaging pixels and non-imaging pixels with reduced resolution having a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2; based on the signals, imaging the mask layer so that the imaged dots have a maximum size smaller than (√2*P2), preferably smaller than P2.

[0010] The second aspect is similar to the first aspect, but here the reduction in resolution is done in hardware without having to generate a modified image file. Thus, according to the second aspect, an image file, typically a raster image file, can be sent to a control module for controlling imaging without further processing / manipulating the image data in the image file, and the reduction in resolution can be done "on the fly" in hardware.

[0011] Note that the pitch corresponds to the distance between the centers of adjacent pixels of a row, and this distance is generally equal to the pixel size. The first pitch P1 corresponds to a first resolution R1 , and the second pitch P2 corresponds to a second, lower resolution.

[0012] Preferably, the second resolution R2 and the imaging settings for imaging are selected such that after exposing the relief precursor through the imaging mask layer and developing the exposed relief precursor, a surface structure of mountains surrounded by valleys is generated on the printing relief corresponding to the solid areas.

[0013] Preferably, imaging is done so that the maximum size of the imaged spot is less than 1 / 3*P1+2 / 3*P2, preferably less than (P1+P2) / 2 or even less than P1, and / or preferably greater than P1 / 2. In such an embodiment, the image spots will not overlap and a suitable fine surface structure for printing solid areas can be generated.

[0014] Preferably, the second resolution R2 is less than two thirds of the first resolution R1, preferably equal to or less than half of the first resolution R1, and / or preferably no more than three times less than the first resolution R1. The inventors have found that this resolution reduction provides a good compromise between accuracy and ink density.

[0015] In an exemplary embodiment, generating includes: if the reduced-resolution pixels include more or the same number of imaging pixels as non-imaging pixels in the image file, determining that the reduced-resolution pixels of the modified image file are reduced-resolution imaging pixels; and if not, determining that the reduced-resolution pixels are reduced-resolution non-imaging pixels.

[0016] In an exemplary embodiment, a sampling pattern is superimposed on the reduced resolution pixels before or during imaging of the mask layer so that only a portion of the imaged pixels with reduced resolution are imaged. Although this may be preferred for some applications, in many applications, good results can be obtained when no sampling pattern is superimposed on the reduced resolution pixels before or during imaging of the mask layer.

[0017] Also note that the sampling pattern may be applied in some areas of the modified image file and not in other areas. For example, in very large solid areas, the sampling pattern may be added, while in other smaller areas, the sampling pattern is not superimposed.

[0018] Alternatively or in addition, before generating, a sampling pattern is superimposed on the pixels of the image file to obtain a sample image file, in which a portion of the imaging pixels of the image file are changed to non-imaging pixels, and wherein the generation is based on the sampling image file. Therefore, the sampling pattern can be added to the original image file before reducing the resolution. In this case as well, the sampling pattern can be applied in some areas of the original image file and not in other areas. Further, the sampling pattern used in the original image file can be different from the sampling pattern used in the modified image file. Typically, due to the reduced resolution, it will be preferred to use a fairly dense sampling pattern, such as a checkerboard pattern, in the modified image file, while a less dense sampling pattern can be used in the original image file.

[0019] Preferably, the sampling pattern is a repetition of a block in which one or more imaging pixels are combined with one or more non-imaging pixels. Alternating imaging pixels with non-imaging pixels across the entire block results in a regular sampling, i.e. a regular selection of imaging pixels over the entire block. For example, the sampling pattern is any one of the following patterns or a combination thereof: a single pixel pattern, such as a single pixel checkerboard pattern, a pattern in which each imaging pixel is surrounded by eight non-imaging pixels; a multi-pixel pattern, such as a multi-pixel checkerboard pattern, in which, for example, a cluster of four imaging pixels or four non-imaging pixels corresponds to a checkerboard; a line pattern; a dashed line pattern (e.g. a dashed line); a circle pattern, a grid pattern.

[0020] According to an exemplary embodiment, imaging is performed such that all imaged points have approximately the same size and / or shape. According to another exemplary embodiment, imaging is performed such that the size and / or shape of the imaged points varies according to a regular or irregular pattern. Such different sizes and / or shapes can be achieved by controlling imaging settings and in particular by controlling any one or more of the following imaging settings:

[0021] - intensity values ​​to be used for generating imaging features corresponding to reduced-resolution imaging pixels, for example intensity values ​​for controlling a beam for imaging reduced-resolution imaging pixels of a solid area;

[0022] - a time interval for generating an imaging feature corresponding to a reduced-resolution imaging pixel, such as a time-on value for controlling a beam for imaging the reduced-resolution imaging pixel of a solid area;

[0023] - a beam diameter value or a beam shape value for controlling a beam for imaging reduced-resolution imaging pixels;

[0024] - multiple passes for imaging the solid areas with reduced resolution imaging pixels;

[0025] - an indication of an exposure head of the plurality of exposure heads to be used to generate an imaging feature or group of imaging features corresponding to a pixel or group of pixels of the reduced resolution imaging pixels.

[0026] According to an exemplary embodiment, a modified image file is generated such that it has at least two bits for each reduced-resolution pixel, the at least two bits indicating for each reduced-resolution pixel whether the pixel is one of the following: a non-imaging pixel with reduced resolution, an imaging pixel with reduced resolution to be imaged with a first imaging setting, an imaging pixel with reduced resolution to be imaged with a second imaging setting different from the first imaging setting, and optionally an imaging pixel with reduced resolution to be imaged with a third imaging setting different from the first imaging setting and the second imaging setting, wherein imaging is performed based on the modified image file. These features integrate the indication of the imaging setting to be used into a single modified image file. During imaging of the mask layer, then only information needs to be extracted from this modified image file, without having to refer to other files and / or without having multiple raster image files. Therefore, by generating such a modified imaging file, the imager can be instructed in a convenient manner while allowing imaging settings to be changed. In this way, imaging settings can be changed in a convenient manner during imaging.

[0027] According to an exemplary embodiment, the method further comprises detecting at least one solid area and at least one halftone area in the image file, wherein the generation of the modified image file is performed based on pixels of the at least one solid area, and the modified image file is used to image the at least one solid area. If any halftone area exists, such area may be imaged in a different manner, for example, based on the image file of the first resolution, optionally applying a sampling pattern on one or more halftone areas.

[0028] According to another exemplary embodiment, the method further comprises detecting at least one interior region and at least one edge region in the image file, and the generation of the modified image file is completed based on pixels of the at least one interior region, and the modified image file is used to image the at least one interior region. The at least one interior region and the at least one edge region may include interior regions and edge regions of solid regions, and / or interior regions and edge regions of dots of halftone regions. One or more edge regions may be imaged in different ways, for example based on the image file of the first resolution.

[0029] According to another exemplary embodiment, the method further comprises detecting at least one interior region and at least one edge region in the modified image file. Optionally, a sampling pattern may be applied to at least the interior region, wherein no sampling pattern or a different sampling pattern may be applied to at least one edge region. Additionally or alternatively, one or more edge regions may be imaged in a different manner, for example using different imaging settings compared to one or more interior regions. The at least one interior region and the at least one edge region may include interior regions and edge regions of solid regions, and / or interior regions and edge regions of dots of halftone regions.

[0030] Preferably, the image file is a raster image file. A raster image file may be a 1BPP (1 bit per pixel) file or a multi-level image file with multiple bits per pixel (e.g. so that the pixels can have various gray levels). A raster image file may have any of the following file formats: TIFF, LEN, JPEG, JPG, BMP, JDF, PNG, etc.

[0031] In an exemplary embodiment, a raster image processing (RIP) module converts a source image file (e.g., a pdf file or a ps file) into a raster image file corresponding to an image file having the above-mentioned first resolution R1. The RIP module is a component used in image processing, which generates a raster image file also referred to as a bitmap, which is a pixel-based format. The source image file can be a page description of a high-level page description language (e.g., PostScript), a portable document format, XPS, or another bitmap. In the latter case, the RIP applies a smoothing or interpolation algorithm to the input bitmap to generate an output bitmap. Raster image processing is the process of converting, for example, vector digital information (e.g., a PostScript file) into a high-resolution raster image file. Usually the RIP module is implemented as a software component of an operating system or as a firmware program executed on a microprocessor. The RIP module can also have a layout function. When multiple small images need to be printed, these images can be grouped according to the printing pattern. This grouping can also be done by the RIP module.

[0032] Optionally, the raster image file may include raster image processed data (i.e., bitmap data) and vector coordinates corresponding to the image block. Alternatively, the raster image file with raster image processed data may be part of a job file that further includes vector coordinates. The raster image processed data (i.e., bitmap data) and the associated vector coordinates corresponding to the image block may be used as input for processing the raster image processed data to automatically generate one or more raster image processed image blocks. One or more registration marks may be attached to each such image block, and the one or more image blocks with the registration marks and the corresponding vector coordinates of each image block may be stored in a processing file for creating a printing plate. Moreover, installation device information, barcodes, and other information may be associated therewith and saved to the processing file. In one embodiment, the bitmap information may be stored in a first layer of a template file, wherein the vector coordinates of each image block are stored in a second layer of the template file. In another embodiment, the bitmap information may be stored in a first file, and the vector coordinates of each image block may be stored in a second file associated with the first file.

[0033] According to a third aspect, a method for imaging a mask layer is provided, comprising the following steps: providing a mask layer; receiving an image source file; generating, based on the image source file, a first raster image file comprising imaging pixels and non-imaging pixels of a first resolution R1, and a second raster image file comprising imaging pixels and non-imaging pixels of a reduced resolution R2 lower than the first resolution R1; wherein the second pitch P2 corresponds to the second resolution R2; based on the second raster image file, imaging the mask layer such that the imaged dots have a maximum size of less than (√2*P2), preferably less than P2. The mask layer may be further imaged based on the first raster image file, typically in different passes, preferably such that the imaged dots have a maximum size of less than (√2*P1), more preferably less than P1.

[0034] The preferred ranges and values ​​of R2 and R1 disclosed above for the first and second aspects are also applicable to the third and following aspects. Moreover, the sampling pattern may be superimposed on the pixels of the first grating image file and / or the second grating image file. The sampling pattern may be any one of the patterns disclosed above. Moreover, the imaging based on the second grating image file may be performed so that all the imaging points generated have approximately the same size and / or shape; or so that the size and / or shape of the imaging points are changed according to a regular or irregular pattern. Further, the imaging based on the first grating image file may be performed so that all the imaging points have the same size and / or shape (which may be the same or different from the imaging points generated based on the second grating image file), or so that the size and / or shape of the imaging points are changed according to a regular or irregular pattern (which may be the same or different from the pattern used in conjunction with the second grating image file).

[0035] The source image file may be a page description in a high-level page description language (e.g., PostScript), a portable document format, XPS. The first raster image file and / or the second raster image file may be a 1BPP (1 bit per pixel) file or a multi-level image file with multiple bits per pixel (e.g., so that the pixel can have various gray levels). The first raster image file and / or the second raster image file may have any of the following file formats: TIFF, LEN, JPEG, JPG, BMP, JDF, PNG, etc.

[0036] Optionally, the first raster image file and / or the second raster image file is generated such that each pixel thereof has at least two bits, the at least two bits indicating for each pixel whether the pixel is one of the following pixels:

[0037] - non-imaging pixels;

[0038] - imaging pixels to be imaged using the first imaging setup;

[0039] - imaging pixels to be imaged using a second imaging setup different from the first imaging setup;

[0040] - imaging pixels which are optionally to be imaged with a third imaging setup different from the first imaging setup and the second imaging setup,

[0041] - wherein the imaging is done based on the first raster image file and the second raster image file.

[0042] The present invention also relates to a mask layer obtained by the method of any one of the above embodiments.

[0043] Optionally, the mask layer is arranged as an integral part of the relief precursor on the photopolymerizable layer of the relief precursor, and after imaging, the photopolymerizable layer of the relief precursor is exposed through the mask layer, and the relief precursor is developed to obtain a relief structure. The invention also relates to a relief structure obtained by the method. The relief precursor can be a precursor for an element selected from the group consisting of a flexographic printing plate, a relief printing plate, a letterpress, a gravure, a (flexible) printed circuit board, an electronic component, a microfluidic component, a microreactor, a moving cell, a photonic crystal and an optical element, a Fresnel lens.

[0044] The mask layer can be a separate layer which is usually applied to the relief precursor after removal of the protective layer which may be optionally present, or an integral layer of the precursor which is in contact with the relief layer or an optional layer above the relief layer and is covered by the protective layer which may be present. The mask layer can also be a commercially available negative film which can be produced, for example, by means of a photographic process based on silver halide chemistry. The mask layer can be a composite layer material in which a transparent layer is produced in an otherwise opaque layer by means of an image-based exposure, as described, for example, in EP 3 139 210 A1, EP 1 735 664 B1, EP 2 987 030, A1 EP 2 313 270 B1. This can be done by ablating an opaque layer on a transparent support layer (as described, for example, in U.S. Pat. No. 6,916,596, EP 816 920 Bl), or by selectively applying an opaque layer to a transparent support layer (as described, for example, in EP 992 846 Bl), or by writing directly onto the relief-forming layer, for example by printing with an opaque ink by means of an inkjet (as described, for example, in EP 1 195 645 Al).

[0045] Preferably, the mask layer is an integral layer of the relief precursor and is positioned in direct contact with the relief-forming layer or a functional layer arranged on the relief-forming layer, which is preferably a barrier layer. In addition, the integral mask layer can be imaged by ablation and additionally removed with a solvent or by heating and adsorption / absorption. For example, the layer can be heated and liquefied by selective irradiation with the aid of high-energy electromagnetic radiation, which produces an image-based structured mask for transferring the structure to the relief precursor. To this end, the layer can be opaque in the UV range and absorb radiation in the visible IR range, which leads to heating of the layer and its ablation. After ablation, the mask layer also presents a relief, typically with a lower relief height, for example in the range of 0.1 to 5 μm. In an exemplary embodiment, the optical density of the mask layer in the UV range of 330 to 420 nm and / or in the visible IR range of 340 to 660 nm is in the range of 1 to 5, preferably in the range of 1.5 to 4, and particularly preferably in the range of 2 to 4. The layer thickness of the laser-ablatable mask layer is usually 0.1 to 5 μm. Preferably, the layer thickness is 0.3 to 4 μm, particularly preferably 1 μm to 3 μm. The laser sensitivity of the mask layer (measured as the energy required to ablate 1 cm2 of the layer) can be between 0.1 and 10 mJ / cm2, preferably between 0.3 and 5 mJ / cm2, particularly preferably between 0.5 and 5 mJ / cm2.

[0046] According to another aspect, there is provided a computer program or a computer program product or a digital storage device comprising computer executable instructions which control the method of any one of the preceding embodiments when the program is run on a computer.

[0047] According to another aspect, a control module is provided, which is configured to: receive an image file including imaging pixels and non-imaging pixels of a first resolution R1; based on the image file, generate a modified image file including imaging pixels with reduced resolution and non-imaging pixels with reduced resolution of a second resolution R2 lower than the first resolution R1, or generate signals corresponding to the imaging pixels with reduced resolution and non-imaging pixels with reduced resolution of the second resolution R2; wherein the second spacing P2 corresponds to the second resolution R2; based on the modified image file or the generated signal, control the imaging of the mask layer so that the imaged points have a maximum size smaller than (√2*P2), preferably smaller than P2.

[0048] The technical benefits set out above for the embodiments according to the first and second aspects apply mutatis mutandis to the embodiments of the control module.

[0049] Preferably, the control module is configured to: determine that the reduced-resolution pixels of the modified image file are reduced-resolution imaging pixels if the reduced-resolution pixels include more or the same number of imaging pixels as non-imaging pixels in the image file; and if not, determine that the reduced-resolution pixels are reduced-resolution non-imaging pixels.

[0050] Preferably, the control module is configured to superimpose the sampling pattern on the reduced-resolution pixels so that only a portion of the reduced-resolution imaging pixels are imaged. Preferably, the control module is configured to control the imaging so that all imaging points have approximately the same size and / or shape; or so that the size and / or shape of the imaging points changes according to a regular or irregular pattern.

[0051] Preferably, the control module is configured to generate a modified image file based on the image file, the modified image file having at least two bits for each reduced-resolution pixel, the at least two bits indicating for each reduced-resolution pixel whether the pixel is one of: a reduced-resolution non-imaging pixel, a reduced-resolution imaging pixel to be imaged with a first imaging setting, a reduced-resolution imaging pixel to be imaged with a second imaging setting different from the first imaging setting, and optionally a reduced-resolution imaging pixel to be imaged with a third imaging setting different from the first imaging setting and the second imaging setting, and the control module is configured to control imaging based on the modified image file.

[0052] According to another aspect, a control module is provided, which is configured to: receive an image source file; generate, based on the image source file, a first grating image file including imaging pixels and non-imaging pixels of a first resolution R1, and a second grating image file including imaging pixels with a reduced resolution and non-imaging pixels with a second resolution R2 lower than the first resolution R1; wherein the second pitch P2 corresponds to the second resolution R2; and control the imaging of the mask layer based on the second grating image file so that the imaged dots have a maximum size smaller than (√2*P2), preferably smaller than P2.

[0053] The control module may also be configured to control imaging based on the first raster image file, typically in different imaging passes, and preferably such that imaged dots have a maximum size smaller than (√2*P1), more preferably smaller than P1.

[0054] Moreover, the control module may be configured to superimpose a sampling pattern on pixels of the first raster image file and / or the second raster image file. The sampling pattern may be any one of the patterns disclosed above. Moreover, the control module may be configured to control imaging based on the second raster image file so that all imaged points generated have substantially the same size and / or shape; or so that the size and / or shape of the imaged points change according to a regular or irregular pattern. Further, the control module may be configured to control imaging based on the first raster image file so that all imaged points have the same size and / or shape (which may be the same or different from the imaged points generated based on the second raster image file), or so that the size and / or shape of the imaged points change according to a regular or irregular pattern (which may be the same or different from the pattern used in conjunction with the second raster image file).

[0055] Optionally, the control module may be configured to generate the first raster image file and / or the second raster image file so that they have at least two bits for each pixel, the at least two bits indicating for each pixel whether the pixel is one of the following pixels: a non-imaging pixel, an imaging pixel to be imaged with a first imaging setting, an imaging pixel to be imaged with a second imaging setting different from the first imaging setting, and optionally an imaging pixel to be imaged with a third imaging setting different from the first imaging setting and the second imaging setting, wherein the imaging is controlled based on the first raster image file and the second raster image file.

[0056] According to another aspect, a system for processing a relief precursor is provided, comprising: an imager configured to image a mask layer; and a control module according to any of the above embodiments, which controls the imager. The imager can be a device that selectively removes part of the mask layer, changes the transmittance of the mask layer, or selectively adds an opaque material to the substrate layer or the relief precursor. Preferably, the imager removes part of the mask layer or changes the transmittance of the mask layer, which can be achieved by using an electromagnetic radiation beam. Most preferably, the imager removes part of the mask layer by ablation, wherein an electromagnetic radiation beam is used. Preferably, the wavelength of the electromagnetic radiation beam is in the range of 700nm to 12000nm.

[0057] Optionally, the system further comprises any one or more of the following components: at least one transport system configured to transport the relief precursor, a storage device, an exposure device configured to expose the relief precursor through an imaged mask layer, a developing device configured to remove at least a portion of unexposed material from the relief precursor, a drying system, a post-exposure device, a cutting device, an installation station, a heater.

[0058] According to a further aspect of the invention, there is provided a system having a user interface, the user interface providing a user with a choice between different imaging methods, preferably including the imaging methods of the first aspect and / or the second aspect and / or the third aspect. Optionally, the system may be configured to query the imager in order to obtain the capabilities of the imager (e.g. supported imaging methods, supported resolutions, information about possible settings of the imaging beam, etc.), and based on the information obtained, the information presented to the user by the user interface may be adapted. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The accompanying drawings are used to illustrate presently preferred non-limiting exemplary embodiments of the method, control module and system of the present invention. The above and other advantages of the features and objects of the present invention will become more apparent and the present invention will be better understood from the following detailed description when read in conjunction with the accompanying drawings, in which:

[0060] Figure 1 An exemplary embodiment of a method for imaging a mask layer is schematically illustrated.

[0061] FIG. 2A to FIG. 2E Different structures of image points are schematically illustrated.

[0062] Figure 3 and Figure 4 Further exemplary embodiments of methods for imaging a mask layer are schematically illustrated.

[0063] Figure 5A and Figure 5B An image showing the surface structure of a solid area of ​​an exposed and developed printing plate imaged according to an exemplary embodiment of the present method.

[0064] FIG. 6A to FIG. 6E Exemplary embodiments of sampling patterns that may be used in exemplary embodiments are illustrated.

[0065] Figure 7 A schematic diagram of an exemplary embodiment of a system for producing relief printing plates / sleeves is illustrated.

[0066] Figure 8 A schematic diagram illustrating an exemplary embodiment of a control module arranged downstream of a RIP module is illustrated.

[0067] Fig. 9 A schematic diagram of another exemplary embodiment of a control module is illustrated.

[0068] Fig.10 and Fig.11 Further embodiments of methods for imaging a mask layer are schematically illustrated. DETAILED DESCRIPTION

[0069] Figure 1 , Figure 3 and Figure 4 Different exemplary embodiments of a method for imaging a mask layer, in particular regions of the mask layer corresponding to solid regions, are illustrated. Figure 1 , Figure 3 and Figure 4 In the figure, the solid area is a circular area, but the skilled person understands that the area can also have any shape.

[0070] exist Figure 1 , Figure 3 and Figure 4 In the first step of the method, an image file including imaging pixels and non-imaging pixels of a first resolution R1 is received. The imaging pixels are represented as black squares. Figure 1 , Figure 3 and Figure 4 In a second step, a modified image file is generated based on the image file having the first resolution. The modified image file includes reduced-resolution imaging pixels (shown in black) of a second resolution R2 lower than the first resolution R1 and reduced-resolution non-imaging pixels. The first pitch P1 corresponds to the first resolution R1, and the second pitch P2 corresponds to the second resolution R2. The generating may include: if the reduced-resolution pixels include more or the same number of imaging pixels as the non-imaging pixels in the image file, determining that the reduced-resolution pixels of the modified image file are reduced-resolution imaging pixels; and if not, determining that the reduced-resolution pixels are reduced-resolution non-imaging pixels.

[0071] In the example, R1 is, for example, 2540 dpi, corresponding to a pitch of 10 microns, and R2 is 1270 dpi, corresponding to a pitch of 20 microns. However, in other examples, these values ​​may be different. Another example is R1=5080 dpi and R2=2540 dpi or R2=5080 / 3 dpi or R2=1270 dpi. Preferably, the second resolution R2 is less than two thirds of the first resolution R1, more preferably equal to or less than half of the first resolution R1, and / or preferably less than the first resolution R1 by no more than 3 times, unless the first resolution R1 is high enough to allow a further reduction in resolution.

[0072] Optionally, in Figure 3 and Figure 4 In a next step illustrated in , before or during the imaging of the mask layer, a sampling pattern is superimposed on the reduced resolution pixels so that only a portion of the imaged pixels with reduced resolution are imaged. Figure 3 In , the sampling pattern is added to the modified image file before imaging, while in Figure 4 In , sampling patterns are added "on the fly" during imaging. Figure 1In some embodiments, no sampling pattern is superimposed on the pixels with reduced resolution before or during imaging of the mask layer. In other non-illustrated embodiments, a sampling pattern may be superimposed on the pixels of the image file to obtain a sample image file in which a portion of the imaged pixels of the image file are changed to non-imaged pixels, and wherein the generation of the modified image file is based on the sampled image file.

[0073] Preferably, the sampling pattern is a repetition of a block in which one or more imaging pixels are combined with one or more non-imaging pixels. Figure 3 and Figure 4 In the example of FIG. 4 , a checkerboard sampling pattern is used. However, other sampling patterns may also be used. FIG. 6A to FIG. 6E Different sampling patterns that can be used are illustrated. Fig. 6A is a single pixel pattern, here a single pixel checkerboard pattern. Figure 6B is a multi-pixel pattern, here a two-pixel checkerboard pattern. Figure 6C is a two-pixel line pattern. Fig.6D is another line pattern that includes lines aligned with rows or columns of pixels. Fig. 6E is a grid pattern comprising lines aligned with pixel rows and lines aligned with pixel columns. Preferably, the sampling pattern is a fairly dense pattern when applied to the modified lower resolution file. However, when the sampling pattern is applied to the image file having the first resolution, a less dense sampling pattern may also be used, such as a pattern in which each imaging pixel is surrounded by at least eight non-imaging pixels.

[0074] exist Figure 1 , Figure 3 and Figure 4 In the final step of an embodiment of the invention, the mask layer is imaged using the modified image file so that the imaged dots have a maximum size that is less than (√2*P2), preferably less than P2. For example, for the illustrated example, the size of the imaged dots may be less than 28*28 microns, more preferably less than 20*20 microns. More preferably, imaging is performed so that the maximum size of the imaged dots is less than 1 / 3*P1+2 / 3*P2, even more preferably less than (P1+P2) / 2 or even less than P1, and preferably greater than P1 / 2. Imaging may be performed so that all imaged dots have approximately the same size and shape, such as Figure 1 , Figure 3 and Figure 4 shown. FIG. 2A to FIG. 2E Further examples of how the shape and / or size of image points may be controlled are shown. Figure 2A Corresponds to Figure 1 , Figure 3 and Figure 4 The content shown in the figure, in which the diameter D of the point is much lower than P2, and even smaller than P1. Figure 2BIn the example, D is equal to P2, so that the imaged points touch each other, and Figure 2C In the example of , D is greater than P2, so that the imaged points overlap. Figure 2D In the example of , imaging is performed so that the size and / or shape of the imaged spots changes according to a regular or irregular pattern. Figure 2E As shown, the positions of the imaging points can also be changed relative to each other. All pixels of a row and / or column can be FIG. 2A to FIG. 2C or some pixels can be aligned as in Figure 2E shifted away from the center position as in the example above.

[0075] In some exemplary embodiments, a modified image file is generated such that it has at least two bits for each reduced-resolution pixel, the at least two bits indicating for each reduced-resolution pixel whether the pixel is one of the following pixels: a reduced-resolution non-imaging pixel, a reduced-resolution imaging pixel to be imaged with a first imaging setting, a reduced-resolution imaging pixel to be imaged with a second imaging setting different from the first imaging setting, and optionally a reduced-resolution imaging pixel to be imaged with a third imaging setting different from the first imaging setting and the second imaging setting, wherein imaging is performed based on the modified image file. For example, the first image setting may represent a first diameter of an imaging point and / or a first shape of an imaging point and / or a first position of an imaging point, and the second image setting may represent a second diameter of an imaging point and / or a second shape of an imaging point and / or a second position of an imaging point, etc.

[0076] Figure 5A and Figure 5B There is shown a printing plate having a solid relief 36 with a fine surface structure comprising hills 36a and valleys 36b (typically having a depth between 0.5 μm and 20 μm), the printing plate being obtained using an embodiment of the method disclosed above. Figure 5A The printed board is used in conjunction with the above Figure 1 The method described is similar to that obtained by the method described above, where no sampling pattern is added. Figure 5A A circular solid relief 36 is shown surrounded by another solid relief 36. For completeness, note that Figure 1 An example of producing a single annular solid relief is shown, while Figure 4 A illustrates an example with two solid relief plates having Figure 1 The solid relief plates 36 may be complementary to the annular shapes of the solid relief plates 36, but these are only examples and the solid relief plates may have any desired shape. Between the two solid relief plates 36 there is a non-printing area in the form of a valley 37 having a depth (typically between 30 μm and 4 mm) significantly greater than the depth of the valleys 36b of the surface structure on the solid relief plates 36. Figure 5B The printed board is used in conjunction with the above Figure 3 The method described is similar to the method obtained, where the sampling pattern is added. Figure 5B A circular solid relief 36 is shown surrounded by another solid relief 36. Between the two solid reliefs 36 there is a non-printing area in the form of annular valleys 37 having a depth (typically between 30 μm and 4 mm) significantly greater than the depth of the valleys 36b of the surface structure on the solid relief 36 (typically between 0.5 μm and 20 μm).

[0077] According to one embodiment, the depth of the valleys of the surface structure on the solid relief 36 is between 0.5 μm and 20 μm, preferably between 1 μm and 10 μm, more preferably between 3 μm and 10 μm. According to one embodiment, the halftone dots ( Figure 5A and Figure 5B Not shown, but can be used with Figure 5A and Figure 5B The depth of the valleys of the surface structure on the solid relief combination (of the solid relief combination) is between 0.5 μm and 20 μm, preferably between 1 μm and 10 μm, more preferably between 3 μm and 10 μm. The total relief depth (i.e. the maximum relief depth in large areas where no imaging pixels are present) is preferably between 100 μm and 4 mm, more preferably between 100 μm and 2 mm, and most preferably between 100 μm and 1 mm. The intermediate relief depth (i.e. the relief depth in the areas between the halftone dots, if present ( Figure 5A and Figure 5B The depth of the intermediate layer is preferably between 40% and 60% of the total intermediate depth, for example between 30 μm and 2 mm, more preferably between 40 μm and 1 mm. According to one embodiment, after the relief precursor is exposed and developed, a solid printing relief 36 having a first surface structure of mountains surrounded by valleys is generated in the solid area, and a plurality of halftone dots (not shown) having a second surface structure of mountains surrounded by valleys are generated in the halftone area.

[0078] Figure 7 A system for forming a relief printing plate or sleeve from a relief precursor is illustrated. The system includes a control module 100, an imager 110, an exposure device 120, and a developing device 130. After the mask layer on the precursor is imaged by the imager 110 using a modified image file and / or imaging instructions generated by the control module 100, the precursor is exposed to electromagnetic radiation in the exposure device 120 through the imaged mask layer, so that a portion of the photosensitive layer 16 is cured. The electromagnetic radiation may have a wavelength in the range of 200 nm to 2000 nm, preferably, it is ultraviolet (UV) radiation having a wavelength in the range of 200 nm to 450 nm.

[0079] The electromagnetic radiation changes the properties of the exposed portions of the photosensitive layer 16 so that in a subsequent development device, the unexposed portions of the photosensitive layer are removed by the development device 130 and a relief printing plate or sleeve is formed. Preferably, development is achieved by treatment with a liquid (solvent, water or aqueous solution) or by thermal development, wherein liquefied or softened material is removed.

[0080] The treatment with a liquid can be performed by spraying the liquid onto the precursor, brushing or rubbing the precursor in the presence of a liquid. The nature of the liquid used is guided by the nature of the precursor used. If the layer to be removed is soluble, emulsifiable or dispersible in water or an aqueous solution, water or an aqueous solution can be used. If the layer is soluble, emulsifiable or dispersible in an organic solvent or a mixture, an organic solvent or a mixture can be used.

[0081] For thermal development, a thermal development device can be used, wherein the flexographic plate is fixed on a rotating drum. The thermal development device also includes a component for heating at least one additional layer and a component for contacting the outer surface of the heated at least one additional layer with an absorbent material for absorbing the material in a molten state. The component for heating can include a heatable bottom layer for the flexographic plate and / or an IR lamp arranged above the at least one additional layer. The absorbent material can be pressed on the surface of the at least one additional layer by means of, for example, an optional heatable roller. The absorbent material can be continuously moved on the surface of the flexographic plate while the drum rotates, repeatedly removing the material of the at least one additional layer. In this way, the molten material is removed, while the non-molten areas remain and form a relief.

[0082] The relief printing plate or sleeve may be further processed and may finally be used as a printing plate. Optionally, the system may also be a light finisher or any other post-exposure unit. Optionally, a controller may be provided to control the various units of the imaging system. Optionally, one or more pre-processing modules may be provided upstream of the control module 100, such as a raster image processing (RIP) module that converts an image file, such as a pdf file, into a raster image processing file, see also the discussion below. Figure 8 .

[0083] Figure 8An exemplary embodiment of a control module 100 arranged downstream of a raster image processing module 90 is illustrated. The raster image processing (RIP) module 90 converts a source image file (e.g., a pdf or ps or xps file) into a raster image file (also referred to as a bitmap) having a first resolution R1. Raster image processing is the process of converting, for example, vector digital information (e.g., a PostScript file) into a high-resolution raster image file. Typically, the RIP module 90 is implemented as a software component of an operating system or as a firmware program executed on a microprocessor. The RIP module 90 may also have a layout function. When multiple small images need to be printed, the images may be grouped according to a printing pattern. This grouping may also be accomplished by the RIP module 90.

[0084] The control module 100 is configured to: receive an image file including imaging pixels and non-imaging pixels of a first resolution R1; generate, based on the image file, a modified image file including imaging pixels with a reduced resolution of a second resolution R2 lower than the first resolution R1 and non-imaging pixels with a reduced resolution; and control the imager 110, based on the modified image file, so that the imaged points have a maximum size smaller than (√2*P2), preferably smaller than P2.

[0085] Fig. 9 An alternative embodiment of the control module 100 is shown. In this embodiment, a raster image processing module 90 is included in the control module. The image source file is a raster image that is processed to generate a first raster image file having a first resolution R1 (e.g., 5080 dpi or 2540 dpi) for one or more halftone areas to be printed (usually color), and a second raster image processing file having a lower second resolution R2 (corresponding to a second pitch P2) (e.g., 1016 dpi) for one or more solid areas to be printed (e.g., one or more solid white areas). In this example, it is assumed that solid white areas must be printed, but a similar approach can be used when one or more solid areas of a specific color need to be printed. Optionally, a sampling pattern can be superimposed on the first raster image file and / or the second raster image file. The generated raster image file is then sent to the imager 110 so that imaging is performed based on the first raster image file and the second raster image file, typically in two different passes, so that the reduced-resolution imaging pixels of the white solid area produce imaging dots having a maximum size smaller than (√2*P2), preferably smaller than P2, and so that the halftone area produces imaging dots having a maximum size that may be larger or smaller than P1.

[0086] Fig.10A further exemplary embodiment of a method for imaging a mask layer is illustrated. When an image file having a first resolution R1 is received, the image file is first analyzed to detect any solid areas and any halftone areas in the image file. Next, a modified image file is generated, the first modified image file having a second resolution R2 based on pixels of at least one solid area that is lower than the first resolution R1, and the second modified image file having the first resolution R1 based on pixels of at least one halftone area. During a first pass, the second modified image file having the first resolution R1 may be used to image at least one halftone area 34, see Fig.10 , and during a second pass, the at least one solid area 32 may be imaged using a first modified image file having a second lower resolution R2, see Fig.10 34. For illustration purposes, some portions of the halftone regions are shown (10%, 30%, and 70%), but the skilled person understands that any combination of halftone regions may exist. As illustrated, the diameters d1, d2, d3 of the imaged dots 41 may be different depending on the size of the dots of the corresponding halftone regions 34. Typically, the diameter d4 of the imaged dots 40 in the solid region 32 may be larger than the diameter of the imaged dots in the halftone regions.

[0087] For example, for small tonal values ​​(eg between 0% and 10%), a first diameter d1 may be used such that touching or overlapping imaging points 41 are obtained, see Fig.10 The upper left image and Figure 2B and Figure 2C For larger tonal values, for example between 10% and 50%, a second diameter d2 smaller than d1 may be used so that the imaged points 41 do not overlap, and for even larger tonal values, for example between 50% and 99%, an even smaller diameter d3<d2 may be used, see Fig.10 Alternatively, the sampling pattern can be used for even larger tonal values ​​in combination with larger diameters. For the solid area 32 (100%), the sampling pattern can be combined with a diameter d4>d1 but preferably less than P2, see Fig.10 The image point 40 in the right image and also see Figure 2A , Figure 2D or Figure 2E .

[0088] Embodiments of the invention are particularly useful for classical amplitude modulated (AM) screens, where the distance Dd between adjacent dots of a halftone area is the same for halftone areas with different tonal values. The tonal value of the halftone area is then determined by the size of the grouped imaging pixel groups corresponding to the grouped imaging dots 41 (i.e., the size of the dots). However, the skilled person understands that other embodiments of the invention may be used for frequency modulated (FM) screens or both AM and FM screens, where the distance Dd is not constant.

[0089] Fig.11 A further exemplary embodiment of a method for imaging a mask layer is illustrated. When an image file having a first resolution R1 is received, a modified image file having a second resolution R2 lower than R1 is first generated, see Fig.11 The image file is then analyzed to detect at least one interior region and at least one edge region in the image file, and a sampling pattern is applied to the at least one interior region. The at least one interior region is then imaged using a modified image file including the sampling pattern in the at least one interior region. The imaging settings used in the interior region may be the same as or different from the imaging settings used in the edge region. Optionally, the modified image file may have at least two bits for each reduced-resolution pixel, the at least two bits indicating for each reduced-resolution pixel whether the pixel is one of the following pixels: a reduced-resolution non-imaging pixel, a reduced-resolution imaging pixel to be imaged with a first imaging setting, a reduced-resolution imaging pixel to be imaged with a second imaging setting different from the first imaging setting, and optionally a reduced-resolution imaging pixel to be imaged with a third imaging setting different from the first imaging setting and the second imaging setting.

[0090] In another example not shown, at least one internal area and at least one edge area may be detected in the original image file, and a sampling pattern may be applied to the original image file before reducing the resolution. The at least one internal area and at least one edge area may include an internal area and an edge area of ​​a solid area, and / or an internal area and an edge area of ​​dots of a halftone area.

[0091] Those skilled in the art will readily appreciate that the steps of the various above methods can be performed by a programmed computer. In this article, some embodiments are also intended to cover program storage devices, such as digital data storage media, which are machine or computer readable and encode machine-executable or computer-executable instruction programs, wherein the instructions perform some or all of the steps of the above methods. The program storage device can be, for example, a digital memory, a magnetic storage medium such as a disk and a tape, a hard drive, or an optically readable digital data storage medium. Embodiments are also intended to cover computers programmed to perform the steps of the above methods.

[0092] Although the principles of the present invention have been described above in conjunction with specific embodiments, it should be understood that this description is intended only as an example and not as a limitation on the scope of protection determined by the appended claims.

Claims

1. A method for imaging a mask layer, comprising the steps of: - providing a masking layer; - receiving an image file including imaging pixels and non-imaging pixels of a first resolution R1; - based on the image file, generating a modified image file, the modified image file comprising reduced-resolution imaging pixels and reduced-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein the second pitch P2 corresponds to the second resolution R2; - Based on said modified image file, imaging said mask layer such that the imaged spots have a maximum size smaller than (√2*P2), preferably smaller than P2.

2. A method for imaging a mask layer, comprising the steps of: - providing a masking layer; - receiving an image file including imaging pixels and non-imaging pixels of a first resolution R1; - based on the image file, generating signals corresponding to reduced-resolution imaging pixels and reduced-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2; - Based on the signal, imaging the mask layer such that the imaged spots have a maximum size smaller than (√2*P2), preferably smaller than P2.

3. A method according to any one of the preceding claims, wherein: The image file is a raster image file.

4. The method according to claim 1 or 3, wherein: The modified image file is generated such that the modified image file has at least two bits for each reduced-resolution pixel, the at least two bits indicating for each reduced-resolution pixel whether the pixel is one of: - non-imaging pixels with reduced resolution; - reduced-resolution imaging pixels to be imaged using the first imaging setup; - reduced-resolution imaging pixels to be imaged with a second imaging setup different from said first imaging setup; - reduced-resolution imaging pixels to be imaged, optionally, with a third imaging setup different from said first imaging setup and said second imaging setup, Wherein, the imaging is performed based on the modified image file.

5. The method according to claim 1 or 3, further comprising: - detecting at least one solid area and at least one halftone area in the image file, wherein generating the modified image file is performed based on the pixels of the at least one solid area and the modified image file is used to image the at least one solid area; or - detecting at least one interior region and at least one edge region in said image file, wherein generating said modified image file is done based on said pixels of said at least one interior region and said modified image file is used for imaging said at least one interior region.

6. A method according to any one of the preceding claims, wherein: The generating includes determining that the reduced-resolution pixels of the modified image file are reduced-resolution imaging pixels if the reduced-resolution pixels include more or the same number of imaging pixels as non-imaging pixels in the image file; and if not, determining that the reduced-resolution pixels are reduced-resolution non-imaging pixels.

7. A method according to any one of the preceding claims, wherein: Prior to the generating, a sampling pattern is superimposed on pixels of the image file to obtain a sample image file in which a portion of the imaging pixels of the image file are changed to non-imaging pixels, and wherein the generating is based on the sampled image file.

8. A method for imaging a mask layer, comprising the steps of: - providing a masking layer; -Receive image source file; - based on the image source file, generating a first raster image file and a second raster image file, wherein the first raster image file comprises imaging pixels and non-imaging pixels of a first resolution R1, and the second raster image file comprises imaging pixels and non-imaging pixels with reduced resolution of a second resolution R2 lower than the first resolution R1; wherein the second pitch P2 corresponds to the second resolution R2; - Based on said second grating image file, imaging said mask layer such that the imaged dots have a maximum size smaller than (√2*P2), preferably smaller than P2.

9. The method according to claim 8, wherein: The first raster image file and / or the second raster image file is generated such that it has at least two bits for each pixel, the at least two bits indicating for each pixel whether the pixel is one of the following pixels: - non-imaging pixels; - imaging pixels to be imaged using the first imaging setup; - imaging pixels to be imaged using a second imaging setup different from said first imaging setup; - imaging pixels which are optionally to be imaged with a third imaging setup different from said first imaging setup and said second imaging setup, - wherein said imaging is performed based on said first raster image file and said second raster image file.

10. A method according to any one of the preceding claims, wherein: The first pitch P1 corresponds to the first resolution R1, and wherein the imaging is performed such that the maximum size of the imaging point is smaller than 1 / 3*P1+2 / 3*P2, preferably smaller than (P1+P2) / 2 or even smaller than P1, and preferably larger than P1 / 2.

11. A method according to any one of the preceding claims, wherein: The second resolution R2 is smaller than two thirds of the first resolution R1 , preferably equal to or smaller than half of the first resolution R1 , and / or preferably smaller than the first resolution R1 by no more than three times.

12. A method according to any one of the preceding claims, wherein: Prior to or during said imaging of said mask layer, a sampling pattern is superimposed on said reduced-resolution pixels such that only a portion of said reduced-resolution imaged pixels are imaged.

13. The method according to any one of claims 1 to 7, wherein: Prior to or during said imaging of said mask layer, no sampling pattern is superimposed on said reduced resolution pixels.

14. The method according to claim 7 or 12, wherein: The sampling pattern is a repetition of blocks in which one or more imaging pixels are combined with one or more non-imaging pixels.

15. The method according to claim 7 or 12, wherein: The sampling pattern is any one of the following patterns or a combination thereof: a single-pixel pattern, such as a single-pixel checkerboard pattern, a pattern in which each imaging pixel is surrounded by eight non-imaging pixels; Multi-pixel patterns, such as multi-pixel checkerboard patterns; line patterns; dotted pattern; Circle pattern; grid pattern.

16. A method according to any one of the preceding claims, wherein: The imaging is performed such that all imaging points have substantially the same size and / or shape; or such that the size and / or shape of the imaging points vary according to a regular or irregular pattern.

17. A mask layer obtainable by a method according to any one of the preceding claims.

18. The method according to any one of claims 1 to 16, wherein: The mask layer is disposed on a photopolymerizable layer of a relief precursor, and wherein, after the imaging, the photopolymerizable layer of the relief precursor is exposed through the mask layer and the relief precursor is developed to obtain a relief structure.

19. A relief structure obtainable by a method according to the preceding claim.

20. A computer program or computer program product or digital storage device comprising computer executable instructions for controlling a method according to any preceding claim when said program is run on a computer.

21. A control module configured to: - receiving an image file including imaging pixels and non-imaging pixels of a first resolution R1; - based on the image file, generating a modified image file or generating a signal, the modified image file comprising reduced-resolution imaging pixels and reduced-resolution non-imaging pixels of a second resolution R2 lower than the first resolution R1, the signal corresponding to the reduced-resolution imaging pixels and reduced-resolution non-imaging pixels of the second resolution R2; wherein, The second spacing P2 corresponds to the second resolution R2; - Based on said modified image file or said generated signal, controlling the imaging of the mask layer such that the imaged spots have a maximum size smaller than (√2*P2), preferably smaller than P2.

22. The control module according to claim 21, wherein: The generating includes determining that the reduced-resolution pixels of the modified image file are reduced-resolution imaging pixels if the reduced-resolution pixels include more or the same number of imaging pixels as non-imaging pixels in the image file; and if not, determining that the reduced-resolution pixels are reduced-resolution non-imaging pixels.

23. The control module according to claim 21 or 22, wherein: The control module is configured to generate, based on the image file, a modified image file having at least two bits per reduced-resolution pixel, the at least two bits indicating, for each reduced-resolution pixel, whether the pixel is one of: - non-imaging pixels with reduced resolution; - reduced-resolution imaging pixels to be imaged using the first imaging setup; - reduced-resolution imaging pixels to be imaged with a second imaging setup different from said first imaging setup; - reduced-resolution imaging pixels to be imaged, optionally, with a third imaging setup different from said first imaging setup and said second imaging setup, And the control module is configured to control the imaging based on the modified image file.

24. A control module configured to: -Receive image source file; - based on the image source file, generating a first raster image file and a second raster image file, wherein the first raster image file comprises imaging pixels and non-imaging pixels of a first resolution R1, and the second raster image file comprises imaging pixels and non-imaging pixels with a reduced resolution of a second resolution R2 lower than the first resolution R1; wherein, The second spacing P2 corresponds to the second resolution R2; - Based on said second grating image file, controlling the imaging of the mask layer such that the imaged dots have a maximum size smaller than (√2*P2), preferably smaller than P2.

25. The control module of claim 24, wherein: The control module is configured to generate the first raster image file and / or the second raster image file such that it has at least two bits for each pixel, the at least two bits indicating for each pixel whether the pixel is one of the following pixels: - non-imaging pixels; - imaging pixels to be imaged using the first imaging setup; - imaging pixels to be imaged using a second imaging setup different from said first imaging setup; - imaging pixels which are optionally to be imaged with a third imaging setup different from said first imaging setup and said second imaging setup, Wherein, the imaging is controlled based on the first raster image file and the second raster image file.

26. A control module according to any one of claims 21 to 25, wherein: The first pitch P1 corresponds to the first resolution R1, and wherein the imaging is performed such that the maximum size of the imaging point is smaller than 1 / 3*P1+2 / 3*P2, preferably smaller than (P1+P2) / 2 or even smaller than P1, and preferably larger than P1 / 2.

27. A control module according to any one of claims 21 to 26, wherein: The second resolution R2 is smaller than two thirds of the first resolution R1 , preferably equal to or smaller than half of the first resolution R1 , and / or preferably smaller than the first resolution R1 by no more than three times.

28. A control module according to any one of claims 21 to 27, wherein: The control module is configured to superimpose a sampling pattern on the reduced-resolution pixels such that only a portion of the reduced-resolution imaged pixels are imaged.

29. A control module according to any one of claims 21 to 28, wherein: The control module is configured to control the imaging so that all imaging points have substantially the same size and / or shape; or so that the size and / or shape of the imaging points change according to a regular or irregular pattern.

30. A system for processing a relief precursor, comprising: - an imager configured to image the mask layer; - A control module according to any one of claims 21 to 29, which controls the imager.

31. A system according to the preceding claim, comprising any one or more of the following items: at least one transport system configured to transport the relief precursor, a storage device, an exposure device configured to expose the relief precursor through an imaged mask layer, a developing device configured to remove at least a portion of unexposed material from the relief precursor, a drying system, a post-exposure device, a cutting device, a mounting station, and a heater.

Images