Orifice surface, print head comprising an orifice surface and method for forming the orifice surface

Abstract

An orifice surface is provided with a coating. A molecule for forming the coating is bonded to the orifice surface through a silicon-carbon bond. The molecule constituting the coating comprises exactly one fluoro-atom. A print head is provided with such orifice surface. In addition, a methods of manufacturing such orifice surface and a method of printing using a print head provided with such orifice surface are disclosed.

Claims

1. An orifice surface comprising: silicon; at least one orifice, said at least one orifice being arranged in the orifice surface for ejecting droplets of a fluid; and a coating, wherein a molecule constituting the coating is bonded to the orifice surface through a silicon-carbon bond, wherein the molecule constituting the coating comprises exactly one fluoro-atom, wherein the molecule constituting the coating has a bonding end and a repellent end, wherein the bonding end comprises a carbon atom that is bonded to a silicon atom of the orifice surface through the silicon-carbon bond, and wherein the fluoro atom is positioned at a terminal carbon atom of the molecule, different from the carbon atom at the bonding end.

2. The orifice surface according to claim 1, wherein the repellent end is an alkyl group comprising exactly one fluoro atom.

3. A print head comprising: the orifice surface according to claim 1.

4. A method for forming the orifice surface according to claim 1, the method comprising the steps of: providing an orifice surface comprising silicon; providing said at least one molecule, the molecule comprising exactly one fluoro atom and a carbon atom for forming a silicon-carbon bond; and bonding the molecule to the orifice surface, wherein the molecule is bonded to the orifice surface through a silicon-carbon bond, wherein the molecule has a bonding end and a repellent end, wherein the bonding end comprises a carbon atom that is bonded to a silicon atom of the orifice surface through the silicon-carbon bond, and wherein the fluoro atom is positioned at a terminal carbon atom of the molecule, different from the carbon atom at the bonding end.

5. The orifice surface according to claim 1, wherein the molecule comprises 8-20 carbon atoms.

6. The orifice surface according to claim 1, wherein the molecule comprises 10-16 carbon atoms.

7. The orifice surface according to claim 1, wherein the molecule comprises 6-25 carbon atoms.

8. The print head according to claim 3, wherein the print head is configured to eject droplets of an ink comprising a water-dispersed resin.

9. A printer comprising: the print head according to claim 3.

10. A method for ejecting droplets onto a recording medium, the method comprising the steps of: providing the print head according to claim 3; providing an ink composition comprising a water-dispersed resin; and ejecting droplets of the ink composition onto the recording medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

(2) FIG. 1A is a schematic representation of an image forming apparatus; and

(3) FIG. 1B is a schematic representation of an ink jet printing assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) The present invention will now be described with reference to the accompanying drawings.

(5) FIG. 1A illustrates an image forming apparatus 36, wherein printing is achieved using a wide format inkjet printer. The wide-format image forming apparatus 36 comprises a housing 26, wherein the printing assembly, for example the ink jet printing assembly shown in FIG. 1B is placed. The image forming apparatus 36 also comprises a storage area configured to store image receiving members 28, 30, a delivery station to collect the image receiving members 28, 30 after printing and a storage area for marking material 20. In FIG. 1A, the delivery station is embodied as a delivery tray 32. Optionally, the delivery station may comprise a processing mechanism configured to process the image receiving members 28, 30 after printing, e.g. a folder or a puncher. The wide-format image forming apparatus 36 further comprises a device that is configured to receiving print jobs and optionally a device that is configured to manipulate print jobs. These devices may include a local user interface unit 24 and/or a control unit 34, for example a computer with a processor.

(6) Images are printed on an image receiving member, for example paper, supplied by a roll 28, 30. The roll 28 is supported on the roll support R1, while the roll 30 is supported on the roll support R2. Alternatively, cut sheet image receiving members may be used instead of rolls 28, 30 of image receiving member. Printed sheets of the image receiving member, cut off from the roll 28, 30, are deposited in the delivery tray 32.

(7) Each one of the marking materials for use in the printing assembly are stored in four containers 20 arranged in fluid connection with the respective print heads for supplying marking material to said print heads.

(8) The local user interface unit 24 is integrated with the print engine and may comprise a display unit and a control panel. Alternatively, the control panel may be integrated with the display unit, for example in the form of a touch-screen control panel. The local user interface unit 24 is connected to a control unit 34 placed inside the printing apparatus 36. The control unit 34, for example a computer, comprises a processor adapted to issue commands to the print engine, for example for controlling the print process. The image forming apparatus 36 may optionally be connected to a network N. The connection to the network N is diagrammatically shown in the form of a cable 22, but nevertheless, the connection could be wireless. The image forming apparatus 36 may receive print jobs via the network. Further, optionally, the controller of the printer may be provided with a USB port, so print jobs may be sent to the printer via this USB port.

(9) FIG. 1B illustrates an ink jet printing assembly 3. The ink jet printing assembly 3 comprises a support that is configured to support an image receiving member 2. The support is shown in FIG. 1B as a platen 1, but alternatively, the support may be a flat surface. The platen 1, as depicted in FIG. 1B, is a rotatable drum, which is rotatable about its axis as indicated by arrow A. The support may be optionally provided with suction holes for holding the image receiving member in a fixed position with respect to the support. The ink jet printing assembly 3 comprises print heads 4a-4d, mounted on a scanning print carriage 5. The scanning print carriage 5 is guided by suitable guides 6, 7 to reciprocate in the main scanning direction B. Each print head 4a-4d comprises an orifice surface 9, which is provided with at least one orifice 8. The print heads 4a-4d are configured to eject droplets of marking material onto the image receiving member 2. The platen 1, the carriage 5 and the print heads 4a-4d are controlled by suitable controls 10a, 10b and 10c, respectively.

(10) The image receiving member 2 may be a medium in web or in sheet form and may be composed of e.g. paper, cardboard, label stock, coated paper, plastic or textile. Alternatively, the image receiving member 2 may also be an intermediate member, endless or not. Examples of endless members, which may be moved cyclically, are a belt or a drum. The image receiving member 2 is moved in the sub-scanning direction A by the platen 1 along four print heads 4a-4d provided with a fluid marking material.

(11) A scanning print carriage 5 carries the four print heads 4a-4d and may be reciprocated in the main scanning direction B parallel to the platen 1, such as to enable scanning of the image receiving member 2 in the main scanning direction B. Only four print heads 4a-4d are depicted for demonstrating the present invention. However, in practice, an arbitrary number of print heads may be employed. In any case, at least one print head 4a-4d per color of marking material is placed on the scanning print carriage 5. For example, for a black-and-white printer, at least one print head 4a-4d, usually containing black marking material is present. Alternatively, a black-and-white printer may comprise a white marking material, which is to be applied on a black image-receiving member 2. For a full-color printer, containing multiple colors, at least one print head 4a-4d for each of the colors, usually black, cyan, magenta and yellow is present. Often, in a full-color printer, black marking material is used more frequently in comparison to differently colored marking material. Therefore, more print heads 4a-4d containing black marking material may be provided on the scanning print carriage 5 compared to print heads 4a-4d containing marking material in any of the other colors. Alternatively, the print head 4a-4d containing black marking material may be larger than any of the print heads 4a-4d, containing a differently colored marking material.

(12) The carriage 5 is guided by guides 6, 7. The guides 6, 7 may be rods as depicted in FIG. 1B. The rods may be driven by suitable drives (not shown). Alternatively, the carriage 5 may be guided by other guides, such as an arm being able to move the carriage 5. Another alternative is to move the image receiving material 2 in the main scanning direction B.

(13) Each print head 4a-4d comprises an orifice surface 9 having at least one orifice 8, in fluid communication with a pressure chamber containing fluid marking material provided in the print heads 4a-4d. On the orifice surface 9, a number of orifices 8 is arranged in a single linear array parallel to the sub-scanning direction A. Eight orifices 8 per print head 4a-4d are depicted in FIG. 1B, however obviously in a practical embodiment several hundreds of orifices 8 may be provided per print head 4a-4d, optionally arranged in multiple arrays. As depicted in FIG. 1B, the respective print heads 4a-4d are placed parallel to each other such that corresponding orifices 8 of the respective print heads 4a-4d are positioned in-line in the main scanning direction B. This means that a line of image dots in the main scanning direction B may be formed by selectively activating up to four orifices 8, each of them being part of a different print head 4a-4d. This parallel positioning of the print heads 4a-4d with corresponding in-line placement of the orifices 8 is advantageous to increase productivity and/or improve print quality. Alternatively, multiple print heads 4a-4d may be placed on the print carriage adjacent to each other such that the orifices 8 of the respective print heads 4a-4d are positioned in a staggered configuration instead of in-line. For instance, this may be done to increase the print resolution or to enlarge the effective print area, which may be addressed in a single scan in the main scanning direction. The image dots are formed by ejecting droplets of marking material from the orifices 8.

(14) Upon ejection of the marking material, some marking material may be spilled and stay on the orifice surface 9 of the print heads 4a-4d. The ink present on the orifice surface 9 may negatively influence the ejection of droplets and the placement of these droplets on the image receiving member 2. Therefore, it may be advantageous to remove excess ink from the orifice surface 9. The excess of ink may be removed, for example, by wiping with a wiper and/or by application of a suitable anti-wetting property of the surface, e.g. provided by a coating.

EXPERIMENTS AND EXAMPLES

(15) Materials

(16) Three different hexynes (hexadec-1-yne (F0), 16-fluorohexadec-1-yne (F1) and 9,9,10,10,11,11,12,12,13,13,14,14,15,15,16,16,16-heptadecafluoro-hexadec-1-yne (F17)) were synthesized according to the method described in: Pujari, S. P.; Spruijt, E.; Stuart, M. A. C.; Rijn, C. J. M.; Paulusse, J. M. J.; Zuilhof, H. Ultralow Adhesion and Friction of Fluoro-Hydro Alkyne-Derived Self-Assembled Monolayers on H-Terminated Si(111) Langmuir, 2012, 28, 17690-17700, and corresponding supporting information.

(17) Silicon wafers, with a 0.2? miscut angle along the (112) plane, were (111)-oriented, n-type, phosphorus-doped and with a specific resistance of 1-10 ?cm.sup.?1, were purchased from Siltronix (France).

(18) Poly (acrylic acid) (PAA, Mn=5000, PDI=1.2), poly(4-chloro styrene) (P4CS, Mn=5000, PDI=1.3), Poly(adipic anhydride) (PAAD, Mn=5000) and Poly(hydroxyl propyl methacrylate) (PHPMA, Mn=5000, PDI=2.20) were provided by Polymer Source. Inc. Polystyrene (PS, Mn=5000, PDI<1.1) and Poly (N-isopropyl acrylamide) (PNIPAM, Mn=5000), were received from Sigma-Aldrich.

(19) All chemicals were used as received unless stated otherwise.

(20) Methods

(21) Fouling Experiment

(22) Clean and well-characterized alkyne modified silicon surfaces were used for the fouling study. The silicon surfaces were submerged in polymer solutions. For all of the experiments, the concentration of the polymer solutions was 10 mg/mL and the experiment was kept for 12 h. All of the surfaces were cleaned and dried with the same procedure (dip the surface into the solvent and shake it for 2 min at 50 rpm, take it out and repeat the above procedure three times and then dried in an 80? C. oven for 2 h). The absorption amount and morphology of polymer on these monolayers were characterized by Ellipsometry. Bare silicon was used as a reference in this polymer absorption survey.

(23) The ellipsometric thickness of the modified surfaces was measured using a rotating Sentech Instruments (Type SE-400) ellipsometer, operating at 632.8 nm (HeNe laser), and an angle of incidence of 70?. The optical constants of a freshly etched H-terminated Si(111) surface were taken as n=3.850 and k=0.057. The thicknesses of the monolayers were determined with a planar three layer (ambient, monolayer, substrate) isotropic model, with assumed refractive indices of 1.00 and 1.46, 1.44, 1.36 for ambient and the F0, F1 and F17 monolayers, respectively. The reported values are the average of at least 5 measurements and the error is less than 0.1 nm.

(24) Static Contact Angle Measurements

(25) The static contact angle (SCA) measurements were conducted using a Kr?ss DSA 100 contact angle goniometer having an automated drop dispenser and image/video capture system. The static contact angles were measured at three different places on a modified surface by dispensing three small droplets (3.0 ?L volume of deionized water) with the help of an automated drop dispenser. The tangent 1 fitting model was implemented for contact angle measurements with an accuracy of ?2.

EXAMPLES

Production Example (General Description)

(26) A three-necked flask was charged with 2 mL alkyne and purged with argon under reduced pressure for 30 min, while being heated to 80? C. Si(111) wafers were cut into 1?1 cm.sup.2 pieces. The surfaces were sonicated for 5 min in pure acetone and subsequently cleaned using air plasma (Harrick Scientific Products, Inc. Pleasantville, N.Y.) for 5 min and quickly transferred to freshly prepared, argon-saturated 40% aqueous ammonium fluoride solution for 15 min. The surfaces were again rinsed with water and dried with a stream of argon. These samples were then immediately transferred into the flask, which was immediately depressurized again. The reaction mixture was kept at 80? C. for 16 h. The sample was then removed from the flask and immediately extensively rinsed with CH.sub.2Cl.sub.2, sonicated for 5 min in CH.sub.2Cl.sub.2 to remove physisorbed molecules, and blown dry with a stream of dry argon. The surfaces were directly used for surface characterization or stored in the glovebox until fouling experiment.

Production Example 1

(27) F1 (16-fluorohexadec-1-yne) was used as alkyne. Modification of a Si (111) surface using this alkyne resulted in the formation of a modified Si surface (Ex 1).

Comparative Example 1

(28) F0 (hexadec-1-yne) was used as alkyne. Modification of a Si (111) surface using this alkyne resulted in the formation of a modified Si surface (CE 1).

Comparative Example 2

(29) F17 (9,9,10,10,11,11,12,12,13,13,14,14,15,15,16,16,16-heptadecafluoro-hexadec-1-yne) was used as alkyne. Modification of a Si (111) surface using this alkyne resulted in the formation of a modified Si surface (CE 2).

(30) Comparison Experiment 1

(31) The anti-fouling property of the modified Si surfaces was investigated using ellipsometry. Using ellipsometry, the thickness increase of the different monolayers after dipping into polymer solutions was measured. The thickness increase is a measure for fouling. The smaller the thickness-increase of a monolayer is, the better the anti-fouling property of that monolayer. The results are summarized in table 1.

(32) TABLE-US-00001 TABLE 1 Thickness increase of different monolayers. Polymer Ex 1 (thickness CE 1 (thickness CE 2 (thickness solution: (nm)) (nm)) (nm)) PAAD 0.03 0.20 4.02 PHPMA 0.04 1.00 1.50 PNIPAM 0.01 0.36 0.52 P4CS 0.01 2.12 0.08 PS 0.03 0.52 0.07 PAA 0.02 0.12 0.02

(33) The thickness of the monolayer according to the present invention (Ex 1) hardly increased for any of the polymer solutions tested. Hence, the modified Si surface according to the present invention has an excellent anti-fouling property.

(34) The Si surface modified with the non-fluorinated alkyne (CE 1) showed a thickness increase for 5 of the polymer solutions tested. Hence, CE 1 has a poorer anti-fouling property compared to the surface according to the present invention. The other silicon surface not according to the present invention (CE 2) showed a thickness increase for all polymer solutions tested. Hence, the modified silicon surface according to the present invention has a better anti-fouling property than the modified silicon surfaces not according to the present invention (CE 1 and CE 2).

(35) Comparison Experiment 2

(36) Static contact angle measurements were performed for the three different modified Si surfaces (Ex 1, CE 1 and CE 2). The results are summarized in table 2.

(37) TABLE-US-00002 TABLE 2 SCA measurements for different monolayers. Sample Ex 1 CE 1 CE 2 SCA(Water) (?) 94 ? 2 110 ? 1 117 ? 2

(38) The SCA for Ex 1 is smaller than the SCA for CE 1 and CE 2. Consequently, the modified Si surface according to the present invention (Ex 1) is a little more wettable than the modified Si surfaces not according to the present invention (CE 1, CE 2). However, the value of the SCA for Ex 1 is such that the modified Si surface according to the present invention still provides sufficient anti-wetting property.

CONCLUSION

(39) The modified silicon surface according to the present invention has an improved anti-fouling property compared to the modified silicon surfaces not according to the present invention, while having an acceptable anti-wetting property.

(40) Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually and appropriately detailed structure. In particular, features presented and described in separate dependent claims may be applied in combination and any combination of such claims are herewith disclosed.

(41) Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. The terms a or an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly.

(42) The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.