Ink-jet Technique Research Articles

Calibration of a radioactive ink-based stack phantom and its applications in nuclear medicine.

This paper describes a stack phantom useful for imaging complex activity distributions. It is based on images printed with radioactive ink using a commercial ink-jet printer. The application for the phantom is in the evaluation of planar and SPECT scintillation camera images and for validation of Monte Carlo simulated images. The accuracy in generating the activity distributions on paper sheets is especially important. Here we describe the calibration procedure for the ink-jet printer. The goal of the printer calibration is to find the relationship between the digital image count (voxel grey level) and its corresponding activity on the paper sheets (radioactivity). The relationship between the voxel grey level and the radioactivity on the paper sheets (measured by scanning technique and well counter) was found to be logarithmic, and a 3rd degree polynomial was found to fit the relationship. The distribution of radioactivity in the ink cartridge was investigated by pinhole SPECT. The distribution of (99m)Tc solution was found to be homogeneous in the ink solution. Experimental studies were done directly on Monte Carlo simulated heart images from the NCAT phantom. The result showed that the simulated images are similar to the images measured using the ink-jet technique. This stack phantom could be a promising solution with an advantage that the exact geometry generated in Monte Carlo could be imitated in the phantom. The phantom is a very flexible device and clearly much more versatile than conventional phantoms which have a fixed geometry and spatial limitation.

Catalytic growth of carbon nanotubes and their patterning based on ink-jet and lithographic techniques

We report the catalytic synthesis of carbon nanotubes and two approaches to the catalyst patterning. Aligned multi-wall carbon nanotube (MWNT) arrays were synthesized in the presence of Co nanoparticles that were prepared by a reverse micelle method. By taking advantage of the fact that the Co nanoparticles are dispersible in organic solvent, an ink-jet technique has been applied to the Co nanoparticle dispersion for MWNT patterning. Single-wall carbon nanotubes (SWNTs) were synthesized by using Fe and Mo supported catalysts and the catalyst preparation process was combined with lithographic techniques, leading to formation of nanotubes bridging or crossing the catalyst patterns. These catalyst-patterning techniques, together with recent development of nanotube synthetic methods, may find applications in electronic and electrochemical applications, such as field-emission displays, nanodevices, and fuel cells.

A Reliable Method for Fabricating sub-10 nm Gap Junctions Without Using Electron Beam Lithography

We demonstrate a high yield production scheme to fabricate sub-10 nm co-planar metal-insulator-metal junctions without using electron beam lithography. The fabricating procedure contains two photolithographys followed by shadow evaporation. Ultrasmall gaps were formed in the crossing region of the two metal layers during the evaporation of the second layer. The sizes of the gaps were estimated using scanning electron microscopy images. Poly (3-hexylthiophene-2,5-diyl) layers were deposited on the junctions using a special ink-jet technique. The results of the conductivity measurement of the molecular layer indicate that these junctions can be used in the study of molecular sensors.

A tuneable and highly-parallel picolitre-dispenser based on direct liquid displacement

We present a new method for the highly-parallel and simultaneous delivery of a multitude of reagents in the picolitre range. This method is based on direct displacement of the liquids using an elastomer-stamp, which simultaneously actuates up to 96 dosing channels, at a pitch of 500 μm. We were able to tune droplet volume from 100 to 700 pl and droplet speed from 0.3 to 4 m/s using printheads with 50 μm diameter nozzles. In contrast to all other inkjet techniques the new direct displacement method enables the precise control of dispensing quantity in the picolitre range regardless of reagent viscosity.

19.5 L: Late‐News Paper: Inkjet‐Printed Bus and Address Electrodes for Plasma Display

AbstractA novel inkjet technique for forming bus and address electrodes has been developed. Silver nano‐particles dispersed into organic solvent were employed as a special ink for inkjet printing. Bus electrodes of 50‐μm‐width and 2‐μm‐thickness have been inkjet printed using the nano‐particle ink. The resistivity of the bus electrodes was 2 μΩcm after baking at 300°C for 30 minutes. We have fabricated a PDP test panel using inkjet bus electrodes to study its feasibility.

Inkjet Printed Via-Hole Interconnections and Resistors for All-Polymer Transistor Circuits

All-polymer thin film transistor (TFT) circuits with via-holes and resistors have been fabricated by an inkjet-printing technique. Solvent drops deposited onto an insulating polymer by the inkjet technique are found to form a crater-like hole (see Figure), and the hole can act as a via-hole for a vertical interconnection. With this technique simple integrated circuits, such as inverters, can be created.

Covalent strategy for immobilization of DNA-microspots suitable for microarrays with label-free and time-resolved optical detection of hybridization.

Sequence-specific detection and quantification of nucleic acids are central steps in many molecular biology procedures which have also been transferred to chip-based procedures. Hybridization-based assays can be used to quantify and discriminate between DNA target sequences down to the level of single base mismatches. Arrays of DNA probes immobilized on a support enable simultaneous testing of multiple sequences of a single sample. DNA arrays can be produced either by in-situ synthesis of oligonucleotides or by immobilization of pre-assembled DNA probes. Covalent and directed immobilization improves the reproducibility and stability of DNA arrays. This is especially interesting with repeated use of transducers or chips. Procedures are described for effective covalent immobilization of pre-assembled amino-linked oligonucleotides, by use of ink-jet techniques, on a modified and heated glass surface, with addressable surface areas ranging from 0.01 mm2 to a few mm2. Almost immediate evaporation of the spotted droplets on the heated surfaces leads to very high surface hybridization capacities. The surfaces are suitable for use with a label-free detection method - reflectometric interference spectroscopy (RIfS). It is shown that hybridization capacity and non-specific interaction at these DNA-surfaces can be characterized by use of RIfS. With a consumption of less than 80 ng mm(-2) oligonucleotide and a specific hybridization capacity of more than 300 fmol mm(-2), the activated aminodextran procedure was usually suitable for setting up a DNA array with label-free detection. Non-specific interactions with random oligomers or protein (ovalbumin) were low. Up to 150 repeated regenerations (stripping) of the surfaces by acid treatment and denaturing agents, and 50 days of storage, have been possible without significant loss of hybridization capacity.

Photo Printing by Dye Thermal and Inkjet Techniques – Status and Prospects

Recent progress in inkjet printing has increased quality to near photographic levels so that it is now comparable with that achieved from thermal dye transfer. This Paper compares the technologies, especially with regard to print speed, durability and the versatility of the printing system.At present, there appears to be a need for both inkjet and D2T2, because of the significant differences in performance and end use.

Microfabrication of conducting polymer devices by ink-jet stereolithography

An ink-jet stereolithographic technique for polymer device microfabrication is described. It exploits the simple working principle of an ink-jet printing head in order to build conjugated polymer devices for electronic, sensing, or actuating applications. The polymer, dissolved in a volatile solvent, is ejected drop by drop onto the substrate. This mechanism allows the deposition of polymeric patterns onto different surfaces without the drawbacks, in terms of time, cost, and process flexibility, that could derive from other classical techniques (spin-coating and photolithography). In addition, three-dimensional structures can be fabricated by means of this technique, by simply depositing different layers of polymer, one on top of the other.

Evaluation of the image quality of ink-jet printed paper copies of digital chest radiographs as compared with film: A receiver operating characteristic study

Paper copies of digital radiographs printed with the continuous ink-jet technique have proved to be of a high enough quality for demonstration purposes. We present a study on the image quality of ink-jet printed paper copies of digital chest radiographs, based on receiver operating characteristic (ROC) analysis. Eighty-three digital radiographs of a chest phantom with simulated tumors in the mediastinum and right lung, derived from a computed radiography (CR) system were presented in two series of hard copies as ink-jet printed paper copies and as laser recorded film. The images, with a matrix of 1,760 x 2,140 pixels, were printed with a spatial resolution of 10 pixels/mm in the CR film recorder as well as in the ink-jet printer. On film, every image was recorded in two versions, one optimized for the mediastinum and one for the lungs. On paper, only one image was printed; this constituted an effort to optimize both the mediastinum and the lungs. The ink-jet printed images, printed on a matt coated paper, were viewed as on-sight images with reflected light. The examinations were reviewed by six radiologists, and ROC curves were constructed. No significant difference was found between the performance of film and that of ink-jet paper prints. Because the cost for a paper copy is only a tenth of that of film, remarkable cost reductions can be achieved by using the ink jet technique instead. Our results show that further quality studies of ink-jet printed images are worthwhile.

Demonstration of digital radiographs by means of ink jet-printed paper copies: pilot study.

Different digital medical images have been printed on paper with a continuous ink jet printer, and the quality has been evaluated. The emphasis has been on digital chest radiographs from a computed radiography system. The ink jet printing technique is described as well as the handling of the image data from image source to printer. Different versions of paper prints and viewing conditions were compared to find the optimum alternative. The evaluation has been performed to maximize the quality of the paper images to make them conform with the corresponding film prints and monitor images as much as possible. The continuous ink jet technique offers high-quality prints on paper at a considerably lower cost per copy compared with the cost of a film print. With a future switch-over from diagnosing of digital images on film to diagnosing them on monitors, hard copies for demonstration purposes will occasionally be needed. This need can be filled by ink jet-printed paper copies.

Mechanism of ultrasonic atomization using a multipinhole plate.

Modifying ink-jet techniques used for character displays, an atomizer with a multipinhole plate is trial-made. The pinhole plate with seven pinholes of 80μm in diameter is piezoelectrically driven at 34.4 kHz by a bimorph structure. Due to the intrinsic nature of the technique, important merits such as the uniform diameter of the atomized droplets, easiness of changing the diameter and of control of the atomizing rate may be expected. Employing the trial-made atomizer, the principle and physical properties of the ultrasonic atomization are experimentally studied. The displacement amplitude distribution of the plate, threshold pressure of atomization, phase of ejection, diameter and amount of droplets as a function of applied voltage are measured to make clear the physical properties of the technique. As a result of experiments, it is made clear that the surface tension of the liquid acts as a valve and that the atomizer has a self-acting liquid supply itself and does not need any pumping apparatus.