METHOD FOR PRINTING A SUBSTRATE USING INKJET PRINTING

Description

[0001] The invention relates to a method for printing a substrate using inkjet printing.

[0002] Methods for printing a substrate using inkjet printing are known in a wide variety of forms from the prior art and are used for numerous applications, for example, for printing both rigid and flexible substrates. The inkjet printing method is particularly suitable for specific applications that require the placement of a precise amount of a functional fluid into several, precisely defined surface areas of the substrate, the respective landing zones. Such applications include, for example, technical or medical sensor surfaces, reaction surfaces for medical applications, or pixel surfaces of displays such as LCDs, TFTs, OLED displays, or e-paper.

[0003] WO 2018 / 099583 A1 discloses a method for printing a substrate with a varying pattern of landing zones using inkjet printing. This method enables precise printing with little effort on a landing point grid that is shifted, rotated, or distorted, in particular non-linearly distorted, relative to an ideally orthogonal landing point grid. The lateral resolution is selected to be large enough so that the smallest distance between the nozzle lines is smaller than the minimum distance between the landing zone rows. Given a substrate-specified variation in the distance between adjacent landing zone rows between different landing zone rows (distortion), the position of the landing zones of a landing zone row relative to the nozzle lines is determined, and from this, only the printhead nozzles whose nozzle line intersects a landing zone are controlled according to a nozzle control scheme and a corresponding landing zone type.

[0004] WO 2013 / 145801 A1 discloses a method for easily setting a specific inkjet head rotation angle. An image forming apparatus includes an inkjet head on which a plurality of ejection orifices are formed, a rotation mechanism for causing the inkjet head to rotate about a rotation axis extending in a direction intersecting a sheet of printing paper, a landing position specifying part for specifying the landing position of ink drops ejected from two or more ejection orifices selected from the plurality of ejection orifices, and a rotation angle specifying part for specifying the inkjet head rotation angle based on the distance along the perpendicular direction between the landing positions specified by the landing position specifying part.The two or more ejection ports are ejection ports that do not have mutually adjacent landing positions with respect to the perpendicular direction that is perpendicular to the moving direction of the printing paper.

[0005] From CN 108 602 346 A, a method for producing a layer with a specific thickness using a printer that applies a liquid is known. The method comprises automatically adjusting printing parameters based on specifically measured or estimated ink or substrate properties. In one embodiment, the spreading properties of the ink are used to select the drop size used to produce a specific layer and / or to select a specific initial volume / area or drop density, which is then scaled and / or adjusted to ensure layer homogeneity. In a second embodiment, the expected information per drop is used to nest the drops to carefully control the merging of the deposited drops, thus aiding layer homogeneity.The liquid layer is then cured or baked to create a permanent structure.

[0006] Particularly when printing RGB patterns as color filters on e-paper displays, numerous landing zones are typically printed, whereby the size of each individual pattern to be printed can be very different and can be both very small, for example 40 x 40 µm, and also large, such as 200 x 1000 µm. A typical size of the individual patterns, however, is around 60 x 200 µm. In order to enable a color representation using e-paper, a printed color layer, in particular individual red (R), green (G), and blue (B) pixel areas as filters, is visible in the regions where the underlying e-paper is driven white. In contrast, the e-paper pixels that are driven black absorb the light, so that the printed RGB color filter is only very faintly visible and thus the e-paper pixels appear almost without any color impression. Colored e-paper usually consists of three colored subpixels (RGB) and possiblyAdditionally, a white subpixel represents a pixel of a high-resolution pixel array. Each (colored) subpixel represents a landing zone, and each color represents a separate landing zone type for printing.

[0007] To achieve high-quality print results, especially on the surface of e-paper, it is necessary that the individual subpixels are formed evenly across the entire surface of the substrate. Both the positioning and size of the pixels, as well as the amount of color filter applied to each subpixel as the print's landing zone, are of great importance within narrow limits.

[0008] In order to achieve a reproducible and trouble-free printing result, it is common practice in inkjet printing applications for dosing in the state of the art that the exact same amount of ink or the exact same number of inkjet drops are placed in each landing zone of a landing zone type, i.e. in all landing zones of the same function, color, shape and / or size.

[0009] The eye of an observer is very sensitive in detecting differences in intensity in the printed substrate, especially in the case of color filters of e-paper, especially when several printed individual samples next to and / or below each other have similar defective properties that are at the same time slightly different from the other individual samples in a neighboring region.

[0010] In practice, such slight differences often arise from inherent printhead nozzle variations, whereby the visual impression of one subpixel differs significantly from the other subpixels when the printed areas are different sizes, even though the exact same amount of ink was printed. Conversely, the impression is also significantly different when the area is the same but the amount of ink is slightly different. Thus, positional variations of the printhead nozzles, which lead to area variations, and / or actual volumetric fluctuations in the ink quantity can lead to such undesirable effects.

[0011] Even a different timing of the drops of an individual pattern hitting the substrate can lead to a different optical impression of several individual patterns, since the printing medium on the substrate may not be absorbed immediately and surface tension effects of the drop just printed can lead to a systematic flow of the printing medium towards previously printed drops.

[0012] The invention is therefore based on the object of providing a method for printing a substrate by means of inkjet printing, which enables printing of a substrate efficiently and in a simple manner, wherein the printing result is particularly uniform and free from interference and wherein, in particular, the occurrence of visually conspicuously different zones is avoided.

[0013] The object is achieved according to the invention by a method according to claim 1. Advantageous developments of the invention are specified in the dependent claims.

[0014] In the method according to the invention for printing a substrate using inkjet printing, landing zones are predefined on the substrate, in particular in a landing zone grid consisting of landing zone rows and landing zone rows. The landing zones are each printed with an individual pattern consisting of at least two drops using print head nozzles of at least one print head. For this purpose, the print head nozzles and the surface of the substrate are moved relative to one another during printing, in particular along a fictitious nozzle path. The printing of the drops takes place within at least some of the individual patterns, preferably within each of the individual patterns, in such a way that any mutual influence of the drops within an individual pattern on the substrate is counteracted.

[0015] The method according to the invention advantageously allows for a particularly uniform and interference-free printing result, since the influences of the individual drops of a single pattern on each other are minimized as much as possible, and accordingly, each drop contributes individually and equally to the overall optical result. This is particularly relevant for printing individual patterns consisting of significantly more than one drop on the surface of the substrate, since the adjacent arrangement of at least two identical drops can easily lead to severe and frequent interference with the printed image.

[0016] Printing is fundamentally understood as a process in which a liquid or flowable printing medium is applied to a surface, whereby this occurs in a targeted manner according to a template, a predefined pattern, and / or at a predefined position. According to the invention, the printing process is inkjet printing, i.e., matrix printing, in which the printing medium to be applied is applied to the medium to be printed in drops or as a jet. Accordingly, printing is preferably carried out contactless, i.e., without direct contact between the printing device and the substrate.

[0017] Printing is carried out using one or more print heads, whereby the print head can be moved relative to the substrate to be printed during printing so that different positions on the substrate can be printed. The print head can be stationary and the substrate moved, or the substrate can be stationary and the print head moved. In principle, the print head has at least one print head nozzle for ejecting drops or a jet of the printing medium, whereby preferably numerous print head nozzles are arranged on the print head in a row and particularly preferably equidistant from one another. In addition, the print head nozzles can also be arranged in several rows on the print head, in particular one behind the other in a printing direction and / or laterally offset from one another.Most preferably, the individual print head nozzle rows are laterally offset from one another in such a way that all nozzle paths of the print head have the same distance from one another, thereby achieving a uniform lateral resolution.

[0018] The substrate surface beneath the printhead nozzle area during printing, and preferably during a single printhead pass relative to the substrate surface, is referred to as the printhead trajectory, while the perpendicular projection of each individual printhead nozzle onto the substrate surface along a trajectory completed during printing is referred to as the nozzle trajectory. Accordingly, the nozzle trajectory is not necessarily physically mapped onto the substrate, but is initially a fictitious trajectory. However, if a printhead nozzle were to continuously discharge print media during a linear movement across the maximum print area or along a landing zone line, the nozzle trajectory would be reproduced on the substrate surface by the print media.In principle, the nozzle path can be linear or have any other non-linear profile and / or any angle to the landing zone lines or rows. Particularly preferred is an embodiment of the method that is alignment-free, i.e., without any alignment of the substrate relative to the print nozzle path prior to printing, in particular based on alignment features. A print head with multiple print head nozzles arranged in a row generates multiple fictitious nozzle paths over the substrate surface during a single pass over the substrate, wherein the distance between the nozzle paths corresponds to the native lateral resolution of the print head.

[0019] The printing medium, which is applied to the substrate as drops during printing, can in principle be any liquid and serve any purpose. The printing medium can, for example, be based on an aqueous or non-aqueous solvent and also contain any other functional components, such as dyes and pigments, but also chemically and / or biochemically active substances. Particularly preferably, the printing medium is an ink or a filter dye solution for printing a subpixel of a display.

[0020] The substrate can basically be made from any desired material and have any desired shape, with the substrate preferably having a planar, printable surface and particularly preferably being generally flat, in particular in the form of a plate or film. The substrate can be either rigid or flexible. An example of a flexible substrate is a flexible EPD (electronic paper display), which, as an unprinted substrate, has an original black / white resolution of 150 ppi with a TFT pixel size of 170 µm. To create a color display based on such an EPD, an RGB filter is printed on top of each black / white TFT pixel, with each color pixel usually being somewhat smaller than the TFT pixel size, e.g., only 150 µm. The resulting color display resolution is then, for example, 75 ppi.Preferably, several, for example, four, landing zone grids are arranged offset from one another on the surface of the substrate, with one grid being printed with a red color filter, one grid with a green color filter, one grid with a blue color filter, and the fourth grid remaining unprinted. Furthermore, at least one landing zone of one landing zone type, for example, one color, is preferably arranged in each TFT pixel.

[0021] A key criterion for high quality is the precise placement of color pixels in the designated positions of each TFT pixel. These target positions are typically defined by the substrate, for example, in the form of recesses in the substrate or a TFT grid, as landing zones. While other criteria may also apply, it is usually an essential requirement that the color pixel or a subpixel within the TFT pixel must not overlap into neighboring TFT pixels, but must be located within the TFT pixel area for all pixels via an active matrix display.

[0022] Accordingly, a landing zone is an underlying structure within the display, e.g. a TFT-driven pixel of a display, wherein the landing zones are preferably each intended to be printed with exactly one individual pattern. In principle, the landing zones can be physically predetermined on the substrate or simply represent certain positions on the overall surface that are not directly visible on the substrate itself. A substrate can have one or more different types of landing zones. Different types of landing zones can, for example, be printed with different print media, hold a different amount of print medium, or have different geometries. The landing zone types are preferably arranged systematically on the substrate or are arranged periodically repeating in at least one, preferably two, spatial directions or form repeating, higher-level patterns.Particularly preferably, an e-paper or an EPD has at least three landing zone types in the colors red, green, and blue. Furthermore, it is conceivable that landing zone types of different shapes and / or sizes are provided for one or more of these colors, so that the total number of landing zone types to be printed on the substrate increases accordingly. Thus, several landing zone grids can be arranged offset from one another on a substrate surface, with several landing zone grids preferably being arranged in the space between the other landing zone grids, in particular such that the individual landing zones of the various landing zone grids are repeated periodically along the substrate surface. Very particularly preferably, several landing zone grids are provided with slightly offset origins, with the landing zone grids particularly preferably being formed identically to one another.

[0023] The individual landing zones of the substrate are preferably arranged in a landing zone grid consisting of landing zone rows and landing zone rows, wherein the landing zone rows and the landing zone rows are particularly preferably positioned at a fixed angle and / or in a consistent arrangement to one another over the entire substrate surface. Most preferably, the landing zone rows and the landing zone rows are aligned perpendicular to one another and / or in a rectangular matrix. Although it is preferred that the individual landing zone rows and landing zone rows are formed identically to one another, they can also differ from one another in their size and / or arrangement, up to and including a random placement of the individual landing zones in the landing zone grid, which is then a pseudo-random grid. For the alignment of the substrate relative to the printing device orFor nozzle control, the substrate can also have alignment features that can preferably be detected optically or by other sensors.

[0024] A single pattern is a single printed area, with each individual pattern consisting of at least two print medium droplets or ink droplets printed using one or more print head nozzles. Preferably, each individual pattern is printed in exactly one landing zone, or each landing zone contains exactly one individual pattern. Particularly preferably, all individual patterns for a landing zone type are identical to one another and, most preferably, are printed from an identical arrangement and / or number of print medium droplets.

[0025] To avoid optical disturbances and abnormalities in the print result, the method according to the invention provides that the printing of the drops takes place within at least some of the individual patterns, preferably within each of the individual patterns, in such a way that any mutual influence of the drops within an individual pattern on the substrate is counteracted. Mutual influence of the drops is generally understood to mean that the behavior of a drop impinging on the substrate is changed by a previously placed and / or simultaneously impinging drop compared to the behavior of an isolated impinging drop, at least to such an extent that the optical impression of the print result changes.

[0026] An example of such an influence is the convergence of two drops on the substrate, which typically reduces the size of the covered area and simultaneously increases its intensity. An influence can also arise if an area of ​​the substrate to be printed is already wetted by a drop that has previously landed in a neighboring area with a part of the impacted drop or a component of the impacted drop, such as its solvent. Avoiding mutual influence, however, does not fundamentally rule out the possibility of the drops touching each other on the substrate; rather, a contact-free or spaced-apart placement of the drops is only one possible implementation. Mutual influence can also be avoided if the interaction between the drops is symmetrical, i.e.that all drops of an individual pattern influence each other to the same extent and, for example, the drops are printed at the same distance from each other and / or at the same time on the substrate.

[0027] Mutual interference can be reduced or even prevented, in particular, by spatially and / or temporally controlling at least one print head and, in particular, the individual print head nozzles for printing the droplets within at least some of the individual patterns, preferably within each of the individual patterns. This control is particularly preferably carried out in such a way that droplet placement within an individual pattern on the substrate is achieved with the least possible interactions and, in particular, interaction-free droplet placement. Within the scope of such spatial and / or temporal control, the order, temporal sequence, and / or spatial position of the droplet placement can be varied or adapted.

[0028] In order to achieve particularly fast printing and particularly precise positioning of the drops at the same time, a preferred embodiment of the method according to the invention for printing a substrate provides that the printing of all drops of an individual pattern and / or all drops of the area below the print head takes place during exactly one relative movement of the print head and the substrate, in particular in exactly one pass.

[0029] In an advantageous development of the method according to the invention for printing a substrate, the printing of all the drops of an individual pattern takes place within a time interval of less than 100 ms, preferably less than 50 ms, more preferably less than 10 ms, and most preferably less than 1 ms, thereby preventing, in a particularly simple manner, mutual influence caused by a droplet running into the area of ​​a subsequently impacting drop on the substrate. Because all the drops impact the substrate almost simultaneously, the condition of the substrate is identical for all the drops, and moreover, the interaction between two adjacent drops printed in an individual pattern, to the extent that such an interaction occurs, occurs for each of the drops through the respective other drop to the same extent, so that both drops ultimately lead to an identical optical impression of the printed substrate.Furthermore, it is preferred that the printing from all adjacent print head nozzles into a single landing zone takes place simultaneously and / or the printing of all drops of an individual pattern takes place one after the other and / or in this order in the direction of movement of the print head relative to the substrate.

[0030] A particularly preferred embodiment of the method according to the invention provides that all drops of an individual pattern are placed on the substrate in such a way that the ink of the individual drops does not come into contact with the ink of all other drops, in particular of the respective individual pattern, on the substrate, in order to prevent multiple drops from merging. The volume of a drop and / or the spacing of adjacent printed drops is preferably selected such that the spacing of the drops on the substrate is as small as possible, thus achieving good ink coverage. With such non-contact placement, the drops can then be applied in any desired order and / or in any desired temporal sequence.

[0031] In order to particularly effectively counteract mutual influences between the drops, a preferred embodiment of the method according to the invention provides that all drops of all individual patterns of a single landing zone type below the print head are printed in a single pass and / or during exactly one relative movement of the print head and the substrate, in particular in exactly one pass, exclusively individual patterns of a single landing zone type are printed with the one print head or with a single one of several print heads, wherein preferably each of the individual patterns is printed completely or all drops of the respective individual pattern are printed at the same time. It is very particularly preferred that only one pass is made per landing zone type or that exclusively all individual patterns of a specific landing zone type are printed during exactly one pass.Furthermore, it is preferred that no drops are printed in individual patterns of a different landing zone type below the print head during a specific pass.

[0032] To increase the position resolution beyond the native position resolution of the print head, the printing of each individual pattern and / or each movement path of the print head relative to the substrate is preferably carried out in k Interlacing passes, whereby the print head and the surface of the substrate are moved relative to each other by a lateral interlacing distance x = j × a k be transferred, whereby a the smallest distance between two nozzle paths, especially the native print resolution, or the distance a two adjacent print head nozzles of the print head. Particularly preferred is j< k chosen. j preferably chosen from the set of all natural numbers including zero. The integer jcan vary from pass to pass or be the same for several passes or the entire print. Thus, the number of interlaces k used to increase the print resolution, so that with a native print resolution of 600 ppi and a k = 4 an effective print resolution of 2400 ppi can be achieved on the substrate.

[0033] In order to further minimize or even completely eliminate an undesired or asymmetric interaction of the drops of an individual pattern, in an advantageous development of the method according to the invention, the printing of all drops into each individual pattern during an interlacing pass takes place in less than 100 ms, preferably in less than 50 ms, particularly preferably in less than 10 ms and most particularly preferably in less than 1 ms.

[0034] Although the substrate can in principle be any surface, the substrate is preferably a display surface and particularly preferably the surface of an e-paper, so that a corresponding development of the method according to the invention for producing colored e-paper is provided. The particular challenge compared to conventional inkjet printing, for example the printing of a graphic on paper, is that a periodic pattern of repeating color pixels is to be printed, on which local optical errors and irregularities are particularly easily noticeable, so that a particularly precise and trouble-free print result over the entire printed area is necessary. Accordingly, it is also particularly preferred that the individual patterns and / or the individual pattern types are filter surfaces of a display, in particular of an e-paper.

[0035] Several embodiments of the method according to the invention are explained in more detail below: A flexible e-paper display as an example of a flexible substrate with a black / white resolution of 150 ppi and a TFT pixel size of 170 µm each is to be printed with a single filter color. Each color pixel is to be slightly smaller than the TFT pixel size, i.e. approximately 150 µm. Accordingly, landing zones for receiving the filter color are provided on the substrate in a rectangular grid consisting of landing zone lines and landing zone rows. The landing zone lines run approximately in a printing direction in which the substrate can be moved beneath a print head with sixteen print head nozzles arranged in a row in order to be able to print on the substrate. However, in principle there is no need for the landing zone lines to be precisely aligned parallel to the printing direction.

[0036] In practice, and in contrast to this highly simplified example, it is typically not a single landing zone grid that is printed, but rather several offset landing zone grids, with the individual landing zones of a landing zone type being arranged in a repeating pattern on the substrate. Typically, at least one landing zone of a landing zone type, for example, a color filter area, is printed into a color pixel.

[0037] For technical reasons, however, it is not always possible to manufacture the substrate surface to be printed in such a way that drops hitting the substrate surface are immediately and completely absorbed by the substrate at the point of impact. In particular, it can happen that drops within an individual pattern are arranged in such a way that the printed drops touch each other on the substrate. In this case, surface tension effects of the still "wet" ink and the substrate could cause several drops of an individual pattern to merge. However, the exact resulting geometry of the merged drops is significantly influenced by the spatial and temporal sequence of the applied drops.

[0038] This results in various possibilities for printing a substrate for e-paper using inkjet printing according to an embodiment of the method according to the invention, wherein the landing zones on the flexible substrate of the e-paper are each printed with an individual pattern consisting of at least two droplets using the print head nozzles of at least one print head. The method is generally operated, and in particular the at least one print head is controlled, such that the printing of the droplets within each individual pattern occurs with the smallest possible mutual influence of the droplets within each individual pattern on the substrate.

[0039] A preferred embodiment of the method, with minimal possible mutual influence between the droplets, initially provides for the selection of a number of individual patterns, each of which is then printed completely in a single pass of the print head or during a single relative movement of the print head to the substrate. All droplets of an individual pattern are printed within a maximum of 2 ms.

[0040] In a special embodiment of the process with the smallest possible mutual influence of the drops, the printing of all drops of each individual pattern or of each individual pattern of a specific individual pattern type, for example the red pixels, takes place during exactly one relative movement of the print head relative to the substrate, whereby on the one hand all drops of an individual pattern are printed in very rapid temporal sequence and on the other hand in a fixed sequence that is repeated for all individual patterns.

[0041] Furthermore, the drops of an individual pattern are preferably positioned such that, at least at the moment of impact on a surface of the substrate, they do not come into direct contact with another drop. In particular, it is preferred to position the drops such that they do not come into contact with each other at all or only very late, shortly before complete drying, on the substrate.

[0042] Largely uniform printed individual patterns, in particular of the same landing zone type, for example a respective filter area of ​​a color, can be achieved within the scope of a possible embodiment of the printing method with the smallest possible mutual influence of the droplets everywhere on the substrate if all droplets of all printed individual patterns are completely printed during the same travel or relative movement. For this purpose, it is advantageous if the spacing of the print head nozzles corresponds to the desired spacing of the droplets on the substrate surface, i.e. the desired print resolution in the lateral direction. Alternatively, it is also conceivable to use a print head with several rows of print head nozzles arranged one behind the other and laterally shifted to one another in order to achieve a higher print resolution than the native resolution of a single row of print head nozzles.

[0043] Alternatively or additionally, the lateral resolution of the print head can be increased by moving the print head laterally over a landing zone after an initial relative movement. A further relative movement then prints additional drops into the spaces between previously printed drops. However, to prevent unwanted interaction between the drops, all drops deposited during the first relative movement of the print head to the substrate are deposited in the individual pattern almost simultaneously (typically < 1 - 2 ms), while the next relative movement, and accordingly the next drop deposition in this individual pattern, typically occurs approximately 0.5 s to 2 s later.

[0044] For example, an e-paper display might consist of 84.5 micrometer square black / white pixels, and it might be desired to print with red, green, and blue color filter inks. In the simplest case, therefore, three landing zone types are required: one for red, one for blue, and one for green pixels. To increase placement accuracy, it might be desired to cover the substrate surface with n =3 movements, ie relative movements, so that the native resolution of the print head is increased from, for example, 1200 dpi to 3 x 1200 = 3600 dpi.

Claims

1. A method for printing on a substrate by means of inkjet printing, in which method - landing zones are specified on the substrate and - the landing zones are each printed with an individual pattern consisting of at least two droplets by means of print head nozzles of at least one print head, wherein - the print head nozzles and the surface of the substrate are moved relative to one another during printing, characterized in that - the printing of the droplets within at least a part of the individual patterns, preferably within each of the individual patterns, is performed such that mutual influence of the droplets within an individual pattern on the substrate is counteracted.

2. The method for printing on a substrate according to claim 1, characterized in that the spatial and / or the temporal control of the at least one print head for printing the droplets within at least a part of the individual pattern, preferably within each of the individual patterns, is performed such that an interaction-free drop placement within an individual pattern on the substrate is achieved.

3. The method for printing on a substrate according to claim 1 or 2, characterized in that the printing of all droplets of an individual pattern and / or of all droplets of the area below the print head is performed during exactly one relative movement of the print head and the substrate, in particular in exactly one pass.

4. The method for printing on a substrate according to at least one of the preceding claims, characterized in that the printing of all droplets of an individual pattern is performed within a time interval of less than 100 ms, preferably of less than 50 ms, more preferably of less than 10 ms, and most preferably of less than 1 ms.

5. The method for printing on a substrate according to at least one of the preceding claims, characterized in that all droplets of an individual pattern are placed on the substrate in such a way that the ink of the individual droplets does not come into contact with the ink of all other droplets, in particular of the respective individual pattern, on the substrate, in order to prevent the multiple droplets from coalescing.

6. The method for printing on a substrate according to at least one of the preceding claims, characterized in that - all droplets of all individual patterns of a single landing zone type are printed below the print head in a single pass and / or - during exactly one relative movement of the print head and the substrate, in particular in exactly one pass, exclusively individual patterns of a single landing zone type are printed using the one print head or using a single one of a plurality of print heads, wherein - preferably, each of the individual patterns is printed completely or all droplets of the respective individual pattern are printed at the same time.

7. The method for printing on a substrate according to at least one of the preceding claims, characterized in that, in order to increase the positional resolution beyond the native positional resolution of the print head, the printing of each individual pattern and / or each trajectory of the print head relative to the substrate is performed in k interlacing passes, wherein the print head and the surface of the substrate are offset relative to one another by a lateral interlacing distance x = j × a k during each of the passes, wherein a is the smallest distance between two nozzle paths and is preferably j < k.

8. The method for printing on a substrate according to at least one of the preceding claims, characterized in that the printing of all droplets in each individual pattern during an interlacing pass is performed in less than 100 ms, preferably in less than 50 ms, more preferably in less than 10 ms, and most preferably in less than 1 ms.

9. The method for printing on a substrate according to at least one of the preceding claims, characterized in that the substrate is a display surface and in particular the surface of an e-paper.

10. The method for printing on a substrate according to at least one of the preceding claims, characterized in that the individual patterns and / or the individual pattern types are filter surfaces of a display, in particular an e-paper.