Method for printing features on a page of a passport and respective device for printing features on a page of a passport

Abstract

The present invention provides a method for printing features on a page (205) of a passport, the method comprising the following steps: - applying a first ink (211) to the page (205) of the passport on a first area (221) in the form of a first feature (111), - allowing the first ink (211) to sink into the page (205) of the passport to a first depth (231), - applying a second ink (212) to the page (205) of the passport on a second area (222) in the form of a second feature (112) at a second depth (232) including a depth of 0 - fixing the first feature (111) in the first area (221) at the first depth (231) and fixing the second feature in the second area (222) at the second depth (231). Further it is provided a device for printing features on a page (205) of a passport.

Description

[0001] The present invention provides a method for printing features on a page of a passport and a respective device for doing so.

[0002] Passports of most of the countries have the form of a booklet comprising between a front cover and a back cover at least one or more pages which are made of paper or at least a fiber-based sheet material. In the last time, there were made some efforts to put information also on said pages and to protect the information on said pages. Often the paper or a fiber-based sheet material then is further laminated with a polymer sheet cover layer in order to protect the information.

[0003] According to the present invention, the inventors have found a method and device which make it easier to incorporate information on these respective pages of the passport which may be made of paper or at least a fiber-based sheet material and which make it tamper-proof. The above-mentioned problem is solved by a method having the features defined in claim 1.

[0004] In particular, a first ink is applied to a respective page of the passport on a first area and forms a first feature. This first ink is allowed to sink into the page to a first depth.

[0005] Further, it is applied a second ink to the page on a second area. The second ink applied on the second area forms a second feature at a second depth. This depth may be a depth within the page or on the surface of the page such that the depth includes a depth of 0.

[0006] The page may be a paper sheet or at least a fiber-based material sheet. In the broadest sense, a fiber-based material may be used or a material, which allows at least the first ink to sink into the page in the depth direction thereof. It is preferred that this page is provided by one single layer. It may also be provided by a plurality of layers, however, it is beneficial that the page is unlaminated, at least not laminated with a top layer, for example a top layer made by a polymer or plastic material, such that the first ink is not able to sink into the page.

[0007] The second ink may be also provided such that it is either on top of the surface of the page at a depth 0 or, alternatively, also may sink into the page to a second depth.

[0008] The first and second depths may be different depths or the same depths.

[0009] Generally, in the broadest sense, for the first and second inks, the same material may be used. However, it is beneficial to use for the first ink a different material from the material used for the second ink and / or to use for the first ink a different color from the color used for the second ink.

[0010] Any of the first and / or second ink may be applied to the page by inkjet printing. That means droplets of said inks are applied to the surface of the page.

[0011] It is beneficial that for the first ink, which should sink into the page, the respective print head used is configured so that the droplets of the first ink applied to the page are comparably big in relation to the droplets of the second ink. The bigger the droplets of the ink used are, the better the respective ink may sink into the surface and into the page. As long as it is intended that the second ink is maintained on the surface in a depth of 0, the respective print head used for the second ink is configured so that the droplets of the second ink applied to the page are comparably small in relation to the droplets of the first ink.

[0012] Further, the first feature and the second feature are fixed in a respective fixing step at their respective locations in the first depth or, respectively, the second depth. The fixing step may be any process to make the ink to be fixed to the respective page. In the broadest sense, the fixing may be done just by leaving the ink to dry in the surrounding room temperature. There may also be applied a heating step. In particular, such a fixing step may be the step of curing the respective ink for a certain time period by light, in particular UV light or IR light. This curing may in particular initiate an ink polymerization and not only a drying of the ink, such that the ink droplets are polymerized and react to the final structure forming the respective feature.

[0013] In order to let the first and / or second ink to sink into the page to the respective depths, this may be done by waiting a certain time to allow the respective ink to sink into the page and, additionally or alternatively, also a pressure gradient may be applied in order to in a certain way suck the respective ink into the page, which is explained for the further embodiment in one of the subsequent sections of the present disclosure.

[0014] The respective first or second area on which the first or respective second feature is applied correspond to a specific position, in particular in the lateral direction of the page. The first and second area may be also at the same location or may be in different locations in lateral and / or horizontal direction. The features may overlap fully, partially or may not overlap.

[0015] The method steps in claim 1 are preferably applied in the order: 1. applying the first ink, 2. allowing the first ink to sink into the page, 3. fixing the first feature, 4. applying the second ink to the page, optionally 5. allowing the second ink to sink into the page, and 6. fixing the second feature.

[0016] Nevertheless, the respective sequence of the steps in claim 1 is not necessarily the sequence of the features as are given in claim 1. At least for the fixing step, for the first ink and the second ink, different fixing procedures may be provided.

[0017] So, for instance, for the first ink, a UV-curing may be used while the second ink simply dryes in the surrounding environment to fix it on the surface of the page. However, also for the second ink such an UV-curing step may be applied, e.g. with the same UV-curing equipment, e.g. only the time for starting the irradiation of the UV-light may be after the application of the second ink shorter compared to the starting time of UV-irradiation after the application of the first ink. However, when there are provided two features in respective two areas, for example, at specific different depths, this may make the printed page more tamper proof as it is explained in the following.

[0018] Although it is preferably put the information to a page being a part of a passport, the method is not delimited to be applied to the page or pages of the passport but it can be used also for other pages, e.g. a sheet used for and ID card or the like where the substrate shows absorbing capabilities of the different inks.

[0019] According to a further variant, the first ink may be selected from the group of: transparent ink, UV-fluorescence ink, IR ink, UV curable ink, non-colored ink.

[0020] The respective abilities (ink features) transparent, UV fluorescence, IR, UV curable and non-colored describe features of the respective ink itself. The respective ink itself may have any of the features also alone or in combination thereof. As long as in the following "transparent" or "non-colored" is used as further determination of the ink, it is meant that this ink is transparent and or non-colored under the irradiation of light in the visible spectrum. This may not exclude that under UV or IR irradiation, this ink has a colored appearance and / or is opaque.

[0021] IR inks (infrared ink) can be identified only with a specific infrared detector. In opposite to UV (ultraviolet) inspection this is more specific.

[0022] UV fluorescence ink means that when irradiated under UV light, the ink is visible and it is given a certain picture of the first feature. A UV curable ink means that under irradiation with UV light, this ink itself is cured while being polymerized or partially polymerized and, thus, the fixing can be done under UV light.

[0023] Therefore, as long as the first ink is a UV curable ink in the fixing step, it is beneficial to apply UV irradiation to cure this ink in the fixing step.

[0024] Generally, the second ink may be any ink and may also have the same features as the first ink. It is however beneficial that the second ink has different characteristics (e.g. different composition) from the first ink that may make the first ink distinguishing from the second ink under irradiation of light in the visible spectrum and / or UV light and / or IR light. In particular, it is beneficial that the second ink is a colored ink. Colored is meant in the sense that the ink under irradiation with visible light has a certain color.

[0025] In particular, it is beneficial that the second ink has a certain color and / or it may be provided on the top of the page or at least at a lower depth seen from the top compared to the first ink being e.g. an UV fluorescent ink, which may be provided from the top surface seen in a deeper depth as the second ink.

[0026] With this configuration, where the first and second inks have different characteristics and are provided in different layers, the document is made more temper proof, e.g. without the need to laminate the paper.

[0027] According to a further variant, the first feature and the second feature, which are generated by the respective first or respective second ink, may represent the same information. Alternatively, the first and second feature may represent different information.

[0028] Information in this context may be, for example, a date of birth, a specific text containing certain information, a picture of a person or any other content giving a certain information to a user (proprietor of the document and / or third party e.g. governmental Officer). However, the information derivable is then for the first and second feature the same or different. These alternatives may each be combined with the configuration to place the first feature in the first area and the second feature in the second area, such that said areas are completely overlapping, not overlapping or partially overlapping.

[0029] However, the information may be in the delimited special sense an identical shape, for example, of a photo of a person, which shall be identified via the passport. For example, when the first feature and the second feature is representing the same information, this may be the same photo of the face of the person which shall be identified by the passport. This face may be then printed with the first ink and the second ink in different layers. In particular, this face photo may be printed with the first ink to generate a certain watermark within the page and, with the second ink at the same area, in a fully overlapping relationship, this face photo is printed as a colored image e.g. on top of the page. E.g. as two identical photos are used to be printed with the first and second ink, full overlapping means that the two photos printed on top of each other with the first and second ink are fully matching in the depth direction.

[0030] In particular, for printing the aforementioned surface image or images, smaller droplets are used in the respective inkjet print head compared to the case when the ink shall sink into the page.

[0031] According to a further variant of the invention, the first and second area are not overlapping in a direction perpendicular to the surface of the page. Alternatively, the first and the second area are at least partially or fully overlapping in a direction perpendicular to the surface of the page.

[0032] With the combination of the first and second features with the first and second ink at the first and second depth representing the same or different information in overlapping and not overlapping relationship, different aspects concerning improved temper proofness can be provided.

[0033] According to a further embodiment, in the step of allowing the first ink to sink into the page of the passport to the first depth, there is applied a gradient of pressure on the page of the passport. This may either be done by providing from the side at which the ink is provided with a high pressure compared to the back side, such that the pressure gradient is provided from high pressure to low pressure in the direction the first ink sinks into the page.

[0034] Alternatively, or additionally, there may be provided a suction pressure on the back side, that is, the opposite side from the side of the page where the first ink is printed. This pressure gradient thus may be a negative pressure gradient which helps the diffusion of the first ink to sink into the page.

[0035] Such a pressure gradient may also be provided for sucking the second ink to the page to the second depth as long as it is not required that the second ink shall be provided at the depth of 0, that means it shall be provided at the surface of the page.

[0036] By adjusting the pressure gradient and / or the time after application and before starting of fixation and / or the surrounding temperature, the speed of sinking of the respective ink into the page can be controlled. Thus, the ink can sink to a predetermined depth.

[0037] The depth of sinking of the ink can also be visually controlled, such that the fixing of the respective ink is executed as soon as it is observed that the respective ink has sunk to the predetermined depth.

[0038] According to a further development, the first depth to which the first ink sinks and where it is fixed is about halfway the thickness of the page and the second depth of which the second ink is fixed is at the surface, namely at a depth of 0.

[0039] In this case, the size of used droplets for the second ink is smaller compared to the size of used droplets for the first ink. The first ink, when it sinks to halfway of the thickness of the page can then undergo an UV curing for fixing in order to polymerize this first ink.

[0040] When the first feature is thus provided basically halfway the thickness of the page, it is visible from both sides of the page when viewed in transmission or reflection.

[0041] In particular, the thickness of the paper or material used for the page is between 10 g per square meter until 800 g per square meter, preferably between 50 g per square meter and 150 g per square meter.

[0042] According to a further development, the first feature may be composed of more than one UV fluorescent ink, so that the first ink comprises at least the first type of ink and the second type of ink. This first type of ink and the second type of ink may have the constitution (features) defined in claim 2.

[0043] However, the characteristics of the first type of ink and the second type of ink shall be different. This characteristics of the ink may be further different from the second ink.

[0044] However, also for the second ink, there may be provided a first and second type of ink.

[0045] There may also be provided further types of inks so that each of the first and second feature can be set up from a plurality of inks.

[0046] As a specific example for the first ink there may be used a first type ink being an UV-fluorescence ink and a second ink type being transparent and / or UV-fluorescence ink, printed as a greyscale image.

[0047] As alternative a specific example for the first ink there may be used a first type ink being an UV-fluorescence ink and a second ink type being a colored ink.

[0048] For the second ink there may be used a first type ink having one specific color and a second ink having a different specific color. However, for any of the first and second and further types of inks which may be present in the first and second ink, the features of claim 2 may be chosen. It may be the case that the features for and of those inks is different or that only the features for a part of the used inks are different.

[0049] With this configuration, there may be provided in the same layer at the first depths and, respectively, the second depths different information printed by different types of inks.

[0050] This provides a further improved security feature of the page.

[0051] According to a coordinated aspect of the invention, it is also provided a device for printing features on a page of a passport.

[0052] The device comprises a first inkjet printing means. With this inkjet printing means, there is a first ink applied to the page of the passport.

[0053] There is provided a second inkjet printing means for applying a second ink to the page of the passport.

[0054] Additionally, there may be provided a fixing means.

[0055] Further, there may be provided a controller for controlling the time between the operation of the first and / or second inkjet printing means and the operation of the fixing means.

[0056] The controller may be configured to allow the applied first ink to sink into the page to the first depth.

[0057] In particular, an example of this first and second printing means may be the printing heads, in which the respective first and second inks are provided.

[0058] As long as for the first ink, inks of a first or second type or multiple ink types are used, multiple first inkjet printing means may be used. As long as for the second ink, inks of a first or second type or multiple ink types are used, multiple second inkjet printing means may be used.

[0059] Further, the fixing means may be an UV lamp or another light source and / or a heater to apply or any means for applying a respective fixing agent, UV light or heat to the page.

[0060] In particular, in the present case, the fixing means is beneficially used to fix the first ink in the respective first depths. For fixing the second ink, there may not be provided any specific fixing means as the surrounding temperature allows the drying of the second ink on the surface. Thus, in the broadest sense, this fixing means claimed in the claims may be adapted to fix at least one of the first and or second ink.

[0061] As long as the specific device is described, the features of the method described in the foregoing section may also be provided as a configuration of the controller. The controller may be e.g. configured to execute the respective method steps described for the method.

[0062] In particular, the controller may determine a specific waiting time for letting the first and or second ink to sink to the respective depths and then apply and instruct the fixing means to fix the respective ink.

[0063] According to a further development, there is comprised a pressure gradient application means which is configured to apply a gradient of pressure on the page allowing the first ink to sink into the page to the first depths.

[0064] Additionally, as described for the method, there may also this pressure gradient application means which may apply a suction or a pressure from the respective side.

[0065] Further preferred embodiments of the present invention are described in the following with respect to the Figures in which Figure 1 shows a specific example of the different steps to apply a first and second ink at respective depths onto a page of a passport, Figure 2 shows the appearance under different conditions, separately for the image inside the page and the image on top of the page, Figure 3 shows different ways to combine the first and second features to form a tamper-proof page, Figures 4 and 5 show different situations of attack attempts how it would be visible on the page, Figure 6 shows the further variant, where for the first ink two types of inks are used. Figure 7 shows a variant of the example shown in figure 1, where for the first and second ink two types of inks are used, wherein additionally to the sketches corresponding to fig, 1a to e) a visualization under UV-light is shown in Fig. 7 f.

[0066] Figure 1 shows an example of the different steps of a method for printing features (a first feature 111, and a second feature 112) on a page 205 of a passport.

[0067] The upper sketches of Figures 1a to 1e show always a schematic top view of the page 205 and the respective lower sketches of Figures 1a to 1e show a cross-sectional view of the page 205.

[0068] This page 205 may be provided within a passport which may be configured as a book-like shape having a hard front cover and a hard back cover.

[0069] This page may be made of paper or a fiber-based material. At least, the material should be adapted so that the later described used inks (at least the respective first ink) is / are able to sink into the page to form a first feature 111.

[0070] Figure 1b shows a first step in which a first ink 211 is printed on a front surface of the page 205. In the particular case, this ink is printed on in the form of an image showing a face of a person, for example, the face of the passport holder. It is derivable from the cross section in Figure 1b, that the first ink 211 is applied onto the surface and then in a second step, this ink is left to sink into the page 205.

[0071] In the present example, the first ink 211 is sunk approximately halfway in the thickness direction of the page 205 to a first depth 231 (see Fig. 1c).

[0072] Thereafter, as shown in Figure 1d, it is applied an UV irradiation step, such that the first ink 211 is polymerized or partially polymerized at the first depth 231, such that a fixation of the first ink 211 to form a first feature 111 is provided. The first feature 111 in the present case is the image of the face of the person.

[0073] Due to the amount of the used first ink 211 and the droplet configuration, the image may have a certain grayscale appearance within the page.

[0074] Thereafter, it is printed (e.g. step 4 shown in Fig. 1e) a second ink 212 on the surface of the page 205 and this second ink 212 is also fixed by immediate UV irradiation after printing.

[0075] In the present case, there are provided two different inks (first ink 211, second ink 212) having different characteristics, which inks are provided in different layers.

[0076] The first ink 211 is provided within the page 205 at the first depth 231 while the second ink 212 is provided on the surface of the page at a depth 0 (see ref. 232 in fig. 1e).

[0077] However, the present invention is not delimited to provide the second ink 212 at a depth of 0.

[0078] The second ink 212 may be provided at the second depth 232 also within the page 205. It is nevertheless not necessary that the first and second depths 231, 232 are different. However, at least, the first ink 211 provides a first feature 111 and the second ink 212 provides a second feature 112.

[0079] The first and second inks 211, 212 may have as described here the different characteristics or may also be the same ink. Nevertheless, in the present case, the second ink 212 is a colored ink which is UV curable and the first ink 211 is a transparent ink which has UV fluorescence and is UV curable.

[0080] The respective ink used for the first and / or second ink 211, 212 may have one or in combination more, or all of the following features: transparent, UV fluorescence, IR visible, UV curable, non-colored, colored.

[0081] As long as in the present case the ink is described as colored ink, it is meant that the color is visible when the page 205 is irradiated with light in the visible spectrum. The same understanding is applied for the utilization of the term "transparent ink". The ink is transparent after curing, at least under the irradiation of light in the visible spectrum.

[0082] However, UV fluorescence is an ability that when irradiated with UV, as shown in further examples of Figures 2 to 6, there is the image visible or the feature visible, which is not visible when the irradiation is executed with light in the visible spectrum.

[0083] In the present case, the respective first feature 111 and second feature 112 are superimposed in the cross-sectional direction of the page and thus the first area 221, in which the first feature 111 is provided and the second area 222, in which the second feature 112 is provided, are fully overlapping each other (see Fig. 1e).

[0084] However, it is not necessary that the respective first and second areas 221, 222 fully overlap each other, they may also overlap partially or even do not overlap each other at all.

[0085] It is in particular preferred that the ink which is used to be sunk into the page 205 is printed with a larger droplet size than the ink which is used for printing just on the surface, thus, the respective higher droplet size can better diffuse into the paper.

[0086] Nevertheless, also here in the present case, both inks are inks which are UV curable.

[0087] However, it is not necessary to apply this UV-curing step, at least for the second ink, which is provided on the top surface.

[0088] There may be also provided a heat curing or just a curing under room temperature.

[0089] It is also not necessary to have during this curing a polymerization, at least, a certain fixation must be provided to make the respective first and second features 111, 112 permanent.

[0090] Although in the present case, there is described a specific sequence of steps, the respective step sequence can also be changed, there may be printed the first ink 211 and the second ink 212 and thereafter, a common fixation step may be applied simultaneously to both features 111, 112.

[0091] Figures 2a to e show an example of the appearance of the page 205 in a reflectance condition (Figs. 2a and d) under visible light, transmission condition (Figs. 2b and e) under visible light and UV light (Figs. 2c and e). For printing here for any of the examples the ink used is a transparent but UV florescent ink.

[0092] Herein, Figures 2a, b, c show a respective configuration after step 3 (see Fig. 1 e) of polymerizing the first ink (fixing step) to generate the first feature 111, such that the second feature 112 is not provided yet.

[0093] Figures 2d, e and g show a respective configuration, where only the second feature 112 is provided on the surface as it is done in step 4, but where the first feature 111 is left out.

[0094] In the respective Figures, there is always given a view of the front and back sides of the page 205.

[0095] As derivable from Figure 2b compared to Figure 2e, in transmission view, the respective image which is just printed on the front surface (second feature 112) is not visible, while the first feature 111 provided within the page 205 is visible from both sides, and has approximately the same appearance as in the present case the first feature 112 which is provided approximately halfway in the thickness direction of the page 205.

[0096] Nevertheless, as the paper thickness is changed and / or also the respective first feature is not provided halfway but provided more shifted to one of both sides from the center of the page in the thickness direction, then the transmission view from front and back may be slightly different.

[0097] In Figure 2c, the respective first feature 112 is made visible under UV light. As it is provided approximately halfway in the thickness direction of the page 205, it can be seen from the front and back side of the page 205.

[0098] However, if the respective ink is just printed on the front surface and not sunk into the page 205, the respective UV image shown in Figure 2f is only visible on the front side.

[0099] In the reflectance image, as shown in Figures 2a and 2d, there is presently, as a transparent UV fluorescent ink is used, only slightly visible the respective distortion within the page 205 or on top of the page 205, which derives from the respective feature.

[0100] However, for the ink which is used to sink into the page 205, there are preferably used relatively huge-sized ink droplets and / or it is applied a certain predetermined time before the polymerization is started by irradiation, for example with an UV lamp.

[0101] When the respective ink should be maintained on the front surface e.g. at a depth 0, smaller ink droplets compared to the aforementioned huge-sized ink droplets, are used and basically immediately after printing, there is applied the fixation, e.g. with the UV light.

[0102] Figures 2g and h show the position of the first and second feature 111 and 112 made by polymerization of the ink in the thickness direction of the page 205.

[0103] Figures 3a, b, c, d show different situations what the printed features 111, 112 are about and in which areas the respective features are printed.

[0104] In said Figures from top to bottom, there is also here provided the appearance of the page 205 in a reflectance condition under visible light (sketch on the bottom side), transmission condition under visible light (sketch in the middle) and UV light (sketch on the top side).

[0105] Figure 3a shows the situation, wherein as first ink 211, there it is used a transparent ink which is UV fluorescent. This is embedded within the page 205. Under UV light, there is now seen in the sketch on top in Figure 3a the date of birth, May 23rd 1995.

[0106] This is basically not seen in the reflectance view (sketch on the bottom side) and a bit visible seen in transmission view (sketch on the bottom side).

[0107] However, superimposed to this first feature 111, there is generated by the second ink 212 and provided on the top surface, a colored image as well as further details concerning the person which is Petra. For the second ink in this case, multiple types of inks are provided so that each of the second feature is set up from a plurality of inks in order to constitute the colored image.

[0108] In any case, both features protecting each other so as to modify the data in any of them must be counterfeit both.

[0109] Nevertheless, the information contained in the first feature 111 is in the case of Figure 3a different from the information in the second feature 112, which is the picture of the face and related information about the person (e.g. inter alia the signature of Petra).

[0110] However, the areas or portions at which the respective features are provided are overlapping in Figure 3a.

[0111] In Figure 3d, there is provided a situation, wherein on the left side, the respective face image is contained in the first feature and in the second feature and both face images are overlapping each other completely. Additionally, as derivable from Figure 3d, sketch on top thereof, the signature, which is part of the first feature 111, is only provided on the right side. The signature and the image may also be understood as to provide separate features within one layer. In this case, the features corresponding to the image of the face in both layers completely overlap each other.

[0112] In the variant shown in Figure 3c on the surface, there is printed on the left side the image of the face and on the right side a text. Thus, the configuration of the feature or features on the surface is the same as for the variant in Fig. 3d.

[0113] As first feature within the page 205, there is just printed the corresponding feature of the face in the region where the text is provided in the top layer. As the text is seen as second feature and as the image within the page is seen as the first feature, both features contain different information.

[0114] In the variant in Figure 3b, under the image of the face as second feature printed on the surface of the page 205, as first feature and embedded into the paper, the date of birth is provided.

[0115] In all variants in Figures 3, the feature or features printed on the surface are colored features and have no fluorescence, while for the embedded feature, a fluorescent ink is used.

[0116] Figure 4 shows different examples of an attack attempt removing a respective image which constitutes the first feature. In said Figures from top to bottom, there is also here provided the appearance of the page 205 in a reflectance condition under visible light (sketch on the bottom side), transmission condition under visible light (sketch in the middle) and UV light (sketch on the top side).

[0117] In the sequence from left to right in Figure 4, there are given the cycles 0, 1, 2, 3, 4 with which the top image is tried to be remove. After cycle 2, the top picture forming the first feature 111 is completely removed.

[0118] However, also after said removal, at least under UV-radiation, as for the second ink a fluorescent ink is used, the date of birth is still visible in the page 205. Said feature cannot be removed, without destroying the page 205.

[0119] Figure 5 shows a further attack for replacing a top image on the page of the passport.

[0120] On the left hand upper side of Figure 5, the respective appearance of the face image of the person in a reflectance condition under visible light (sketch on the bottom side), transmission condition under visible light (sketch in the middle) and UV light (sketch on the top side) can be derived.

[0121] On the lower left side of Figure 5, there is the shown image inside the page 205 and next to it on the right side is shown the image on the top surface of this page. For the image inside the page 205 the UV-fluorescent ink is used. For the image on the top surface, the colored ink is used.

[0122] In Fig 5, the two sketches denoted with A and B show the image inside the page 205 and the image on the top surface of this page. In this case, the image on the top surface of this page has been replaced by a look alike person's face of the image inside the page 205. On the right side of figure 5 in the top row, the appearance of the appearance in a reflectance condition under visible light (sketch on the left side), transmission condition under visible light (sketch in the middle) and UV light (two sketches on the right side, one from the front side and one form the back side of the page 205) can be derived.

[0123] It can be determined by applying at least one of the respective three radiation conditions whether there has been made a counterfeit attack or not.

[0124] In Fig 5, the two sketches denoted with C and D show the image inside the page 205 and the image on the top surface of this page. In this case, the image on the top surface of this page has been replaced by a face picture of a different person's face compared to the image inside the page 205. On the right side of Figure 5 in the top row, the appearance of the appearance in a reflectance condition under visible light (sketch on the left side), transmission condition under visible light (sketch in the middle) and UV light (two sketches on the right side, one from the front side and one form the back side of the page 205) can be derived.

[0125] Also here it can be determined by applying at least one of the respective three radiation conditions whether there has been made a counterfeit attack or not.

[0126] Figure 6 shows a further example in which the transparent but UV fluorescent ink is used inside the page, however, in this specific case, two types of ink are used for this first ink. In said Figure from left to right, there is also here provided the appearance of the page 205 in a reflectance condition under visible light (sketch on the left side), transmission condition under visible light (sketch in the middle) and UV light (sketch on the right side).

[0127] In transmission and reflectance view, the birth date May 23 rd< 1995 is visible, but with a light appearance.

[0128] Nevertheless, under UV light, in the birth date, there is further the name Petra with the second type of ink 211b printed. This provides a further improved security features. In said Figure, reference numeral 211a denotes a first type of ink. Thus, the first ink is here composed of the first and second type of ink 211a, 211b.

[0129] Figure 7 shows a variant of the example shown in figure 1, where for the first and second ink two types of inks are used, wherein additionally to the sketches corresponding to fig, 1a to e) a visualization under UV-light is shown in Fig. 7 f.

[0130] Namely for the first ink 211, as second type ink 211b an UV-fluorescent ink is used, and as first type ink 211a an transparent ink printed in a greyscale fashion are used. Namely for the second ink 212, a third type ink 212a and as fourth type ink 212b is used. The second type ink 211a may also be an UV-fluorescent ink

[0131] In this case the two ink types of the second ink 212 are named third and fourth type ink as any of the ink types in said example are different from each other. Generally, in the following it is described that the first and second ink each can comprise a first and second type ink or more than two types of inks.

[0132] As a specific example for the first ink there may be used a first type ink being an UV-fluorescence ink and a second ink type being transparent and / or also UV-fluorescence, printed as a greyscale image. For the second ink there may be used a first type ink having one specific color and a second ink having a different specific color. However, for any of the first and second and further types of inks which may be present in the first and second ink, the features of claim 2 may be chosen. It may be the case that the features for and of those inks are different or that only the features for a part of the used inks are different.

[0133] In figure 7 a to e, the same steps are shown as in figure 1, thus for the specific description it is referred to the above section where figure 1 is described. In the case of figure 7, for the first ink 211, as second type ink 211b an UV-fluorescent ink is used, and as second type ink 211a is printed in a greyscale fashion. Namely for the second ink 212, a third type ink 212a and as fourth type ink 212b is used.

[0134] At the right side in Fig. 7f it is visualized how the appearance under UV-light is, namely one can see the birth date in the layer of the first ink with a fluorescent color as for the second type ink 211b an UV-fluorescent ink is used.

[0135] Although in the aforementioned examples, very specific details are described, in the broadest sense, the invention covers the situation described in the general description.

[0136] It is not necessary that the second ink is provided on the top surface, but the second ink can also be provided at a certain depth within the page and sink within the sheet. There may be used the same or different materials for the respective inks.

[0137] Also in the foregoing, a method is described. This method is executed by a respective system which is also derived from the claim and the general description.List of Reference Signs

[0138] 111first feature 112second feature 205page 211first ink 211afirst type ink 211bsecond type ink 212second ink 212athird type ink 212bfourth type ink 221first area 222second area 231first depth of the first feature 232second depth of the second feature

Claims

1. Method for printing features on a page (205) of a passport comprising the following steps: - applying a first ink (211) to the page (205) of the passport on a first area (221) in the form of a first feature (111), - allowing the first ink (211) to sink into the page (205) of the passport to a first depth (231), - applying a second ink (212) to the page (205) of the passport on a second area (222) in the form of a second feature (112) at a second depth (232) including a depth of 0 - fixing the first feature (111) in the first area (221) at the first depth (231) and fixing the second feature in the second area (222) at the second depth (231).

2. Method according to claim 1, wherein the first ink (211) is selected from the group of: a transparent ink, a UV-fluorescence ink, IR-ink a UV curable ink, a non-colored ink, or an ink with a combination of these ink features.

3. Method according to claim 1 or 2, wherein the second ink (212) is a color ink and / or a UV-fluorescence ink and / or an ink having different characteristics from the first ink.

4. Method according to any of the preceding claims, wherein the first feature (111) and the second feature (112) are representing the same information, or the first feature (111) and the second feature (112) are representing different information.

5. Method according to any of the preceding claims, wherein the first area (221) and the second area (222) are not overlapping in a direction perpendicular to the surface of the page (205), or wherein the first area (221) and the second area (222) are at least partially or fully overlapping in the direction perpendicular to the surface of the page (120).

6. Method according to any of the preceding claims, wherein the step of allowing the first ink (211) to sink into the page (205) to the first depth (231) is supported by a gradient of pressure on the page (205).

7. Method according to any of the preceding claims, wherein the first depth (231) is about halfway the thickness of the page (205) and the second depth (232) is at the surface of the page (205) at a depth of 0.

8. Method according to any of the preceding claims, wherein the first feature (111) is composed of more than one UV-fluorescence ink, so that the first ink (211) comprises at least a first type ink (211a) and a second type ink (211b).

9. Device for printing features on a page (205) of a passport comprising - a first inkjet printing means for applying a first ink (211) to the page (205), - at least one fixing means, - a second inkjet printing means for applying a second ink (212) to the page (205), - and a controller for controlling the time between the operation of the first and / or second inkjet printing means and the operation of the fixing means, wherein the controller is configured up to allow the applied first ink to sink into the page to a first depth (231).

10. Device according to the preceding device claim, further comprising pressure gradient application means configured to apply a gradient of pressure on the page (205) allowing the first ink (111) to sink into the page (205) to the first depth (231).

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