Patent Application
20180088506
In a liquid electrophotography (LEP) image printing process, a negatively charged print material (such as ink) is electrostatically provided onto a photoconductive sheet (known as a Photo Imaging Plate, PIP) mounted onto an imaging cylinder to create a print material image. The print material image is transferred from the photoconductive sheet onto a positively charged blanket cylinder, on which it is heated to create a final image in the form of a thin tacky film. The final image film is then transferred from the blanket cylinder onto a print substrate (or print media) moving between the blanket cylinder and a grounded impression cylinder on which it is held.
For a more complete understanding, various examples will now be described below with reference to the accompanying drawings in which:
Some examples described herein provide a method and apparatus for preparing a print substrate (or print media) prior to an image printing process. There is also provided a print substrate and method comprising printing an image using the print substrate.
The present subject-matter is further described with reference to
The conductive top layer 104 of the print substrate 100 may comprise a conductive material. In some examples, the conductive material may be a metal (such as aluminium or any other metallic material). In some examples, the conductive material may be a material such as carbon, Indium Tin Oxide (ITO), or the like. The edges of the conductive top layer 104 may be free or encapsulated.
The conductive top layer 104 may be formed on a base layer 106. The base layer 106 may comprise, for example, a synthetic based material or a paper based material (e.g. paperboard) or any other type of synthetic based material. The surface of the base layer 106 may be coated or uncoated. In one example, the base layer 106 may comprise an uncoated 300 gsm paper board.
The layers of the print substrate 100 shown in
The conductive top layer 104 of the print substrate 100 is able to conduct electric current. In this example, the print substrate 100 may have a low surface resistivity (i.e. surface resistance). For example, the surface resistivity of the print substrate 100 may be of the order of a few Ω/sq (i.e. Ω/□) to a few hundred kΩ/□. In one example, the surface resistivity of the print substrate 100 may be less than 2 MΩ/□.
The resistive top layer 204 of the print substrate 200 may be in the form of a film and may comprise, for example, a plastic such as polyethylene terephthalate (PET), polypropylene, polymethylemetacrylate (PMMA) or any other resistive layer. The resistive top layer 204 may be transparent, mechanically stable, and/or resistive to scratches. The resistive top layer 204 may have a thickness in the range of 4 to 32 microns. However, it will be understood that other thicknesses are possible. The resistive top layer 204 may be a fully resistive plastic film. The resistive top layer 204 of the substrate 200 illustrated in
The resistive top layer 204 may be formed on a conductive layer (for example, a metallic layer) 206. In other words, according to this example, the print substrate 200 comprises a conductive internal layer 206 covered by a resistive top layer 204. The conductive internal layer 206 may comprise, for example, a conductive material. In some examples, the conductive material may be a metal (such as aluminium or any other metallic material). In some examples, the conductive material may be a material such as carbon, Indium Tin Oxide (ITO), or the like. The edges of the conductive internal layer 206 may be free or encapsulated.
The conductive layer 206 may be formed on a base layer 208. The base layer 208 may comprise, for example, a synthetic based material such as a paper based material (e.g. paperboard) or any other type of synthetic based material. The surface of the base layer 208 may be coated or uncoated. In one example, the base layer 208 may comprise an uncoated 300 gsm paper board.
The resistive top layer is able to oppose the flow of electric current. In this example, the print substrate 100 may have a high surface resistivity (i.e. surface resistance). For example, the surface resistivity of the print substrate may be of the order of a few GΩ/□. In one example, the surface resistivity of the print substrate 200 may be greater than 2 GΩ/□.
With reference to
At block 502, 510, 518, 526, the processing module 604 compares the determined surface resistivity of the print substrate 100, 200 to a print range having a lower threshold value for the surface resistivity of the print substrate 100, 200 and an upper threshold value for the surface resistivity of the print substrate 100, 200.
As illustrated in
In the example illustrated in
The surface modification 102, 202 may comprise any modification to the surface of the print substrate 100, 200 (including any material or technique applied to the surface) that can adjust the determined surface resistivity of the print substrate 100, 200 to fall within the print range. Where the surface modification comprises a material that can adjust the determined surface resistivity of the print substrate 100, 200, the material may have other functionalities aside from adjusting the determined surface resistivity of the print substrate 100, 200.
In the example illustrated in
In some examples, the coating material may be in the form of a film forming coating (i.e. a coating material that forms a polymeric film on the surface after curing). In some examples, the coating material may be a polyethyleneimine (PEI) based material such as Michelman Sapphire®, Michelman Digiprime®060, Michelman Digiprime®050 or the like. In some examples, the coating material may be an ethylene acrylic acid (EAA) based material such as Michelman Digiprime® 4431, Michem® In-Line Primer 030 or the like.
The coating material may include an anti-static agent and, where there are different levels of coating material provided, the coating material may include different proportions of anti-static agent at each level. In some examples, the antistatic agent may be, for example, an ionic liquid mixed into the coating material. The ionic liquid may consist of, for example, imidazolium or ammonium cations. In some examples, the antistatic agent may be a solid state salt (i.e. powder or crystals that can dissolve in water) added to the coating material. The solid state salts may be, for example, NaCl, KCl, Na2SO4 or any other solid state salt. The anti-static agent may be selected by the processing module 604 using weight relation calculations.
In some examples, the processing module 604 may select a concentration for the coating material. For example, the coating material may be formed by adding an imidazolium ionic liquid in 10% (w/w) concentration to a polyethylene imine resin dispersion. In other examples, the concentrations may be 3%, 9%, 15%, etc. However, it will be understood that other coating materials and concentrations are also possible.
The processing module 604 may select a coating material to have a certain weight to obtain a desired surface resistivity. In some examples, the coating material may be selected to have a weight in the range of 0.8 and 4 gsm when wet. The processing module 604 may select a thickness in which the coating material is to be applied by the application module 606. The processing module 604 may select a number of layers of coating material to be applied by the application module 606 (such as one layer, two layers, three layers, etc).
In the example illustrated in
With reference to
In the example illustrated in
In some examples, the application module 606 may apply the selected coating material by coating the top layer 104, 204 of the print substrate 100, 200 with one or more layers of the coating material. The coating of the top layer 104, 204 may be performed using any suitable coating technique (for example, gravure). In some examples, applying the surface modification 102, 202 to a top layer 104, 204 of the print substrate 100, 200 may comprise the application module 606 coating a top layer 104, 204 of the print substrate 100, 200 with the selected coating material having a weight and in a thickness selected by the processing module 604. In other words, a layer of coating material may be formed to a selected thickness. In some examples, a layer of coating material may have a thickness of approximately 1 μm. In other examples, a layer of coating material may have a thickness of approximately 2 μm. In some examples, a layer of coating material may have a thickness in the range of approximately 1-2 μm.
The application module 606 may apply the coating material to the print substrate 100 using any appropriate technique. For example, the application module 606 may apply the coating material to the top layer 104, 204 of the print substrate 100, 200 using an applicator such as a roller (for example, a 1.2 BCM anilox roller) or a rod (for example, a RDS2 or RDS3 rod).
In the example illustrated in
In the example shown in
In an example, the application module 606 may apply the selected resistive agent to the conductive top layer 104 of the print substrate 100 by coating the conductive top layer 104 with one or more layers of the selected resistive agent. In one example, the application module 606 may apply the selected resistive agent to the conductive top layer 104 by coating the conductive top layer 104 with two layers of the selected resistive agent with each layer of resistive agent having a thickness of approximately 1 pm. In some examples, a layer of resistive agent may be in the form of a solid ink layer. In some examples, the layer of resistive agent may be a plastic. The application module 606 may apply the resistive agent to the conductive top layer 104 as a thin top coating to control the surface conductivity. Other examples of the resistive agent for coating may be any of those described earlier with respect to the coating material or any other resistive agent to promote or increase the resistivity of the print substrate 100.
The application module 606 may apply the resistive agent to the print substrate 100 using any appropriate technique. For example, the application module 606 may apply the resistive agent to the conductive top layer 104 of the print substrate 100 using an applicator such as a roller (for example, a 1.2 BCM anilox roller) or a rod (for example, a RDS2 or RDS3 rod).
In another example, the application module 606 may apply the selected resistive agent to the conductive top layer 104 of the print substrate 100 by doping the conductive top layer 104 with the selected resistive agent. Examples of the resistive agent for doping may be any of those described earlier with respect to the coating material or any other resistive agent to promote or increase the resistivity of the print substrate 100.
In the example shown in
In an example, the application module 606 may apply the selected conductive agent to the resistive top layer 204 of the print substrate 200 by coating the resistive top layer 204 with one or more layers of the selected conductive agent. In one example, the conductive agent may be in the form of an aqueous polymeric solution. For example, the conductive agent may be in the form of an ionic liquid and may comprise conductive salts (such as cations of ammonium or imidazolium). In some examples, the conductive agent may be in the form of an antistatic agent. The application module 606 may apply the conductive agent to the resistive top layer 204 as a layer of plastic film and the surface conductivity of the resistive top layer 204 may be raised by the addition of a resin having conductive characteristics. Other examples of the conductive agent for coating may be any of those described earlier with respect to the coating material or any other conductive agent to promote or increase the conductivity of the print substrate 200.
The application module 606 may apply the conductive agent to the print substrate 200 using any appropriate technique. For example, the application module 606 may apply the conductive agent 202 to the resistive top layer 204 of the print substrate 200 using an applicator such as a roller (for example, a 1.2 BCM anilox roller) or a rod (for example, a RDS2 or RDS3 rod).
In another example, the application module 606 may apply the selected conductive agent to the resistive top layer 204 of the print substrate 200 by doping the resistive top layer 204 with the selected conductive agent. Examples of the conductive agent for doping may be any of those described earlier with respect to the coating material or any other conductive agent to promote or increase the conductivity of the print substrate 100.
As described above, the surface modification 102, 202 is selected to adjust the surface resistivity of the print substrate 100, 200 to fall within a print range having a lower threshold value for the surface resistivity of the print substrate 100, 200 and an upper threshold value for the surface resistivity of the print substrate 100, 200.
The lower threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 1 MΩ/□, 1.2 MΩ/□, 1.3 MΩ/□, 1.4 MΩ/□, 1.5 MΩ/□, 1.6 MΩ/□, 1.7 MΩ/□, 1.8 MΩ/□, 1.9 MΩ/□, 2 MΩ/□, 2.1 MΩ/□, 2.2 MΩ/□, 2.3 MΩ/□m 2.4 MΩ/□, or 2.5 MΩ/□. In one example, the lower threshold value for the surface resistivity of the print substrate 100, 200 may be at least 1.5 MΩ/□. In another example, the lower threshold value for the surface resistivity of the print substrate 100, 200 may be at least 2 MΩ/□.
The upper threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 50 MΩ/□, 60 MΩ/□, 70 MΩ/□, 80 MΩ/□, 90 MΩ/□, 100 MΩ/□, 110 MΩ/□, 120 MΩ/□, 130 MΩ/□, 140 MΩ/□, 150 MΩ/□, 160 MΩ/□, 170 MΩ/□, 180 MΩ/□, 190 MΩ/□, or 200 MΩ/58 . In one example, the upper threshold value for the surface resistivity of the print substrate 100, 200 may be less than or equal to 150 MΩ/□. In another example, the upper threshold value for the surface resistivity of the print substrate 100, 200 may be less than or equal to 100 MΩ/□.
In a specific example, the lower threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 1.5 MΩ/□ and the upper threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 150 MΩ/□. In other words, the print range may include a surface resistivity of the print substrate 100, 200 from 1.5 MΩ/□ to 150 MΩ/□.
In another specific example, the lower threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 2 MΩ/□ and the upper threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 150 MΩ/□. In other words, the print range may include a surface resistivity of the print substrate 100, 200 from 2 MΩ/□ to 150 MΩ/□.
In another specific example, the lower threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 1.5 MΩ/□ and the upper threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 100 MΩ/□. In other words, the print range may include a surface resistivity of the print substrate 100, 200 from 1.5 MΩ/to 100 MΩ/□.
In another specific example, the lower threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 2 MΩ/□ and the upper threshold value for the surface resistivity of the print substrate 100, 200 may be a value of 100 MΩ/□. In other words, the print range may include a surface resistivity of the print substrate 100, 200 from 2 MΩ/□ to 100 MΩ/□.
The example print ranges with the lower and upper threshold values for the surface resistivity of the print substrate 100, 200 apply to each of the examples described above. It will be understood that other print ranges are possible.
As discussed above, according to the present disclosure, there is provided a print substrate (or print media) 100, 200 comprising a conductive layer 104, 206 and a top layer 104, 204 with an applied surface modification 102, 202. The surface resistivity of the print substrate 100, 200 according to the present disclosure is within a print range having a lower threshold value for the surface resistivity of the substrate 100, 200 and an upper threshold value for the surface resistivity of the substrate 100, 200 due to the surface modification 102, 202 applied to the top layer 104, 204 of the print substrate 100, 200.
The print substrate 100, 200 of the present disclosure may be used in a method of printing an image. For example, the print substrate 100, 200 may be for use in electrophotographic printing.
The following examples are to be understood as being illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative compositions and methods may be devised without departing from the spirit and scope of the present disclosure. Thus, these examples should not be considered as limitations of the present disclosure, but are merely in place to teach how to make and use compositions of the present disclosure.
An example relates to a print substrate (also referred to as a media or sheet) with a conductive top layer. The print substrate with a conductive top layer was observed with a scope connected to a test point and spikes were observed in an ITM power supply. The print substrate was observed as solid ink layers were printed on top of the print substrate. Each ink layer was approximately 1 m thick.
The spikes that appeared during the printing of the first layer were greatly reduced during the laying of the second layer and were completely eliminated during the laying of the third layer and onwards. The surface resistivity of the print substrate with two layers was measured at approximately 1.5 MΩ/ . For a 600V blanket, the expected current is 600V/1.5 MΩ=0.4 mA, which is a low current. Maximal current of the power supply of the press in test was 20 mA.
Another example relates to a print substrate (also referred to as a media or sheet) with a resistive top layer. The print substrate showed strong cling to other print sheets. When measured with an electrometer, the sheets displayed a surface potential of a few 10 s and up to 200 volts. The sheets were coated with a primer containing a conductive salt. The conductive salt included ionic liquids comprising cations of ammonium or imidazolium types, or any other conductivity promoters for aqueous polymeric solutions.
BASF EFKA®IO 6785 (imidazolium ionic liquid) was added in 15% (w/w) concentration to Michelman Digiprime® 060 primer (polyethylene imine resin) and was applied with a 1.2 BCM anilox roller on resistive top substrate. The coating resulted in a surface resistivity of 20-30 MΩ/ .
Other concentrations of 10%, 9% and 3% (w/w) were tested with the same primer, conditions and substrate, and resistivity measurements showed a surface resistivity of approximately 100 MΩ/ , 230M kΩ/ and 800 MΩ/ Under a surface resistivity of 100 MΩ/ , there was no measureable cling and no measurable potential on the sheets after printing. At 230 Mohm, a cling of very few Newton was observed, which did not impede any finishing, and a few 10 s of volts charging was recorded. At about 800 Mohm, a cling of a few Newton was observed and a high charging of up to 200 volts.
The above described method may apply at various levels in a printing process. For example, the method may be programmed internally in a printer. In another example, a non-transitory machine-readable storage medium may be encoded with instructions executable by a processor to perform the method. The method may be used in conjunction with any other programs for processing a three-dimensional object (for example, programs that process three-dimensional models with texture maps).
Examples in the present disclosure can be provided as methods, systems or machine-readable instructions, such as any combination of software, hardware, firmware or the like. Such machine-readable instructions may be included on a machine-readable storage medium (including but is not limited to disc storage, CD-ROM, optical storage, Random Access Memory (RAM), an Electrically-Erasable Programmable Read-Only Memory (EEPROM), a storage drive, etc.) having machine-readable program code therein or thereon. In some examples, the machine-readable storage medium may be non-transitory.
The present disclosure is described with reference to flow charts and/or block diagrams of the method, apparatus and systems according to examples of the present disclosure. Although the flow diagrams described above show a specific order of execution, the order of execution may differ from that which is depicted. Blocks described in relation to one flow chart may be combined with those of another flow chart. It shall be understood that each flow and/or block in the flow charts and/or block diagrams, as well as combinations of the flows and/or diagrams in the flow charts and/or block diagrams can be realised by machine-readable instructions.
The machine-readable instructions may, for example, be executed by a general purpose computer, a special purpose computer, an embedded processor or processors of other programmable data processing devices to realise the functions described in the description and figures. For example, a processing apparatus or processor may execute the machine-readable instructions. Thus, functional modules (such as the measurement module 602, processing module 604, and application module 606 described herein) of the apparatus and devices may be implemented by a processor executing machine-readable instructions stored in a memory, or a processor operating in accordance with instructions embedded in logic circuitry. Generally, modules may be any combination of hardware and programming to implement the functionalities of the respective modules. In some examples, the combinations of hardware and programming may be implemented by a processor and executable instructions stored on a non-transitory machine-readable storage medium. The term “processor” is to be interpreted broadly to include a processing unit, central processing unit (CPU), application-specific integrated circuit (ASIC), logic unit, programmable gate array, etc. The methods and functional modules may all be performed by a single processor or divided amongst several processors.
Such machine-readable instructions may also be stored in a machine-readable storage that can guide the computer or other programmable data processing devices to operate in a specific mode.
Such machine-readable instructions may also be loaded onto a computer or other programmable data processing devices, so that the computer or other programmable data processing devices perform a series of operations to produce computer-implemented processing, thus the instructions executed on the computer or other programmable devices provide a means for realising functions specified by flow(s) in the flow charts and/or block(s) in the block diagrams.
Further, the teachings herein may be implemented in the form of a computer software product, the computer software product being stored in a storage medium and comprising a plurality of instructions for making a computer device implement the methods recited in the examples of the present disclosure.
While the method, apparatus and related aspects have been described with reference to certain examples, various modifications, changes, omissions, and substitutions can be made without departing from the spirit and scope of the present disclosure. It should be noted that the above-mentioned examples illustrate rather than limit what is described herein, and that many alternative implementations may be designed without departing from the scope of the appended claims. For example, a feature or block from one example may be combined with or substituted by a feature/block of another example.
The word “comprising” does not exclude the presence of elements other than those listed in a claim, “a” or “an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims.
The features of any dependent claim may be combined with the features of any of the independent claims or other dependent claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/067650 | 7/31/2015 | WO | 00 |
