Thermal Transfer Printing Research Articles

The effect of transfer printing on pentacene thin-film crystal structure

The thermal deposition and transfer printing method had been used to produce pentacene thin films on SiO2∕Si and plastic substrates poly(methyl methacrylate) (PMMA) and poly(vinyl pyridine), respectively. X-ray diffraction patterns of pentacene thin films showed reflections associated with highly ordered polycrystalline films and a coexistence of two polymorph phases classified by their d spacing, d(001): 14.4 and 15.4Å. The dependence of the c-axis correlation length and the phase fraction on the film thickness and printing temperature were measured. A transition from the 15.4Å phase towards 14.4Å phase was also observed with increasing film thickness. An increase in the c-axis correlation length of approximately 12%–16% was observed for pentacene (Pn) films transfer printed onto a PMMA coated poly(ethylene terephthalate) substrate at 100–120°C as compared to as-grown Pn films on SiO2∕Si substrates. The transfer printing method is shown to be attractive for the fabrication of pentacene thin-film transistors on flexible substrates partly because of the resulting persistence in the quality of the pentacene film.

Color Properties of Specular Reflections

A study has been carried out on the effect of the optical density of inks on the specular reflectance of a printed surface. Samples of cyan, magenta, and yellow ink were printed with a liquid electrophotographic, an offset lithographic, and a thermal transfer printer. Specular reflectance was measured using a goniophotometric instrument to produce the bidirectional reflectance distribution function. The results clearly demonstrated that the amount of specular light reflected from a printed surface depends strongly on the optical density of the ink. A linear correlation was observed between the total amount of specular light reflected from the surface and the square of the transmittance of the ink layer. A highly transparent ink (e.g., yellow ink measured with red light) reflected approximately twice as much specular light than a highly absorbing ink (e.g., yellow with blue or cyan with red). It is suggested that specular reflections from surfaces below the ink layer can contribute significantly to overall specular reflectance of a printed image.

Evaluation of Printing Papers for Thermal Transfer Printers Based on Real Contact Area Using a Contact Microscope

The thermal transfer print method is to print ink on the surface of paper by pressurizing ink and paper directly with a thermal head, and heating the places to print. A principle of the thermal transfer printing is similar to that of the offset printing. A tribological contact problem occurs in the offset printing. Thus the thermal transfer printers are suffering from the similar contact problem between the ink and the paper since the surface of the plain paper has roughness and it is very difficult to make the contact situation constant at all time. It is necessary to deeply understand the contact between paper and the solid ink to achieve the high-resolution printing on even the rough plain paper. So far the stylus type and the laser type profilometers were used to evaluate the printing quality for various papers. However there is no attempt to examine the printing quality, optical density, from the view point of real contact area. Then, the relationship between the optical density and the real contact area on the paper side was experimentally obtained in this paper with a contact microscope. As a result, the correlation could be found between the optical density and the real contact area.

Study on a Thin Film Thermal Print Head for High Definition Multi-Level-Tone Color Imaging Use

We studied a 600 dpi high definition thermal print head. Fast thermal response, thermal resistance, uniform contact pressure on print media, and micro process are necessary to achieve 600 dpi high definition thermal transfer print. Therefore, we examined a new structure of a low thermal diffusivity layer on a high thermal diffusivity substrate, and optimum new design of the head shape. As a result, we could drive a 600 dpi thermal print head at high speed and high duty. We studied thermal print head to achieve multi-level tone in thermal transfer printing, which required appropriate heat control of heating elements on the head and varying the amount of resin ink melted by the energized head edge, that is, varying dot diameter as needed. After a series of examination, we came to the conclusion that head form especially the part between a heating elements and head edge is deeply related to the property of the tone. This meant that optimization of the head form was the key to the solution. Thus we have attained multi-level-tone printing by varying dot diameter in 16 levels with the enhanced print head.

A Coupled Thermal-Structural Nip Analysis of Thermal Dye Transfer Printing

A coupled two-dimensional thermal-structural nip analysis using a commercially available finite element package, i.e., ABAQUS, has been developed to simulate the thermal dye transfer (TDT) printing process. Incorporating all key components in the thermal printing process, this simulation model includes a simplified printhead, the layered structure of a thermal media pair, i.e., dye donor ribbon and receiver, and the elastomer-covered platen roller. The unique feature in this simulation is its capability of simultaneously solving the structural and contact mechanism of the approaching surfaces during thermal printing and calculating the heat transfer through these interfacial contacts.During the simulation, the model mimics the movement of the dye donor ribbon and receiver, which are brought into intimate contact between the printhead and the platen roller. Thermal energy or heat generated by pulsing the heating elements in the printhead flows through the media and across interfacial contact pairs, e.g., printhead and dye donor ribbon, and dye donor ribbon and receiver (where the dye diffusion occurs). The contact area and contact pressure at the interfaces, temperature distribution, thermal history, and stress-strain state are all calculated for each component. The model has been successfully implemented to investigate the effects of platen rollers, to study the media and equipment interactions, and to help identify essential material properties for media design.

D<sub>2</sub>T<sub>2</sub> Printing after Two Decades

Dye diffusion thermal transfer printing has been in the marketplace for 20 years. During that time, the technology has evolved from a special purpose curiosity to an everyday product that consumers use in their homes and drug stores. What has changed over this time to bring about this revolution? This paper will discuss the evolution of the technology over time, and the technology enablers that were key elements in the evolution.

Design of a color card printer robot

This paper presents the development of color card printer robot. The color card printer robot utilizes dye-sublimation/resin thermal transfer printing technology to achieve its direct-to-card photo-quality output. The design includes the printer robot mechanisms, control circuits system, control firmware, communication interface, and color image processing algorithms. The card used here is a standard CR-80 PVC card with a size of 54 mm /spl times/ 86 mm and the printing resolution is 300 dpi. The control circuits system is based on a digital signal processor (DSP) and a FPGA, which is a programmable logic device to contain embedded arrays, offering up to 100,000 gates. The digital logic modules implemented in FPGA include DRAM access module, data and I/O control module, communication control unit, LCD display module, keypad, sensors module, thermal printing head (TPH) control module, and motors control module. The specifications of the color card printer robot are also listed.

Spectral reflection and dot surface prediction models for color halftone prints

The proposed new spectral reflection model enhances the classical Clapper-Yule model by taking into account the fact that proportionally more incident light through a given colorant surface is reflected back onto the same colorant surface than onto other colorant surfaces. It comprises a weighted mean between a component specifying the part of the incident light that exits through the same colorant as the colorant from which it enters (Saunderson corrected Neugebauer component) and a component specifying the part of the incident light whose emerging light components exit from all colorants (Clapper-Yule component). We also propose models for taking into account ink spreading, a phenomenon that occurs when printing an ink halftone in superposition with one or several solid inks. The ink-spreading model incorporates nominal-to-effective surface coverage functions for each of the different ink superposition conditions. A system of equations yields the effective ink surface coverages of a color halftone as a weighted mean of the ink surface coverages specific to the different superposition conditions. The new spectral reflection prediction model combined with the ink-spreading model yields excellent spectral reflection predictions for clustered-dot color halftones printed on an offset press or on thermal transfer printers.

Design of a Thermal Print Head by Contact Pressure Analysis

The printing method of the thermal transfer printer is to push an ink ribbon that is heated and melted by a thermal head to a printing paper, and transfer the ink to desired positions on the paper. Thus it is important to place the heater of the thermal head at the position where the contact pressure becomes most high. The visco elastic properties of the ink, PET and platen rubber were measured with a rheometer. The contact pressures on the thermal head were calculated by FEM. The contact pressures under consideration of visco elasticity were different from those calculated by elastic analysis. We designed the thermal print head by using this analytical result, and confirmed the print characteristic.

On-Demand Direct Printing of Conductive Circuit Pattern by Thermal Transfer Technology

In our R&D study, we found that antenna patterns printed on the film by thermal transfer ribbon bear the basic frequency characteristics as film antenna, which are used for inlet of IC tags, car navigation systems, etc. We are convinced that the manufacturing of film antennas can be more simple process and lower cost by using thermal transfer printing technology.

Effects of copolyester/polycarbonate blend composition on the thermal diffusivity of dye transfer printing

AbstractThe effect of the blend composition on the thermal diffusivity for blends of a poly(ethylene‐co‐cyclohexane 1,4‐dimethanol terephthalate) (PETG) and a bisphenol‐A polycarbonate (PC) that have been used as base films for a thermal dye transfer (TDT) printing system was examined. The inflection point in the thermal diffusivity measured by temperature wave analysis almost matched the inflection point of storage modulus measured by dynamic mechanical analysis. This result implied that the temperature dependence of thermal diffusivity related to the change in the microstructure of the PETG/PC blend. Furthermore, the correlation between the printing sensitivity and the thermal diffusivity at the actual thermal head temperature of TDT printing was found. The thermal diffusivity increased with increasing PC content, while the printing sensitivity decreased. The PETG/PC blend film suitable for the TDT printing base film could be obtained by adjusting the PC content in the blend. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 72–76, 2004

Evaluation of Thermal Conductivities of Printing Papers Using a Thermal Transfer Printer

The printing method of the thermal transfer printer is to push an ink ribbon that is heated and melted by a thermal head to a printing paper, and transfer the ink to desired positions on the paper. If the heating by the thermal head is not sufficient, the ink cannot be melted and cannot be transferred to the paper. Moreover, even if the heating is excessive, a high quality print cannot be done, because an excess amount of ink will be transferred to the paper. The heat generated by the thermal head is transmitted to the printing paper through the ink ribbon. Thus the thermal conductivity of the printing paper affects the temperature rise of the ribbon and as a result printing quality. The thermal conductivity of the paper is commonly measured with a quick thermal conductivity meter. However the printing paper is too thin for the measurement. A new method of evaluating the thermal conductivity of the printing paper using the thermal transfer printer was proposed.

熱転写プリンタにおける圧力の解析(紙送りに関する解析的アプローチ,IIP2004 情報・知能・精密機器部門講演会)

熱転写プリンタにおける圧力の解析(紙送りに関する解析的アプローチ,IIP2004 情報・知能・精密機器部門講演会)

熱転写型プリンタ用ゴム材料のFEM解析(材料力学I-2)

熱転写型プリンタ用ゴム材料のFEM解析(材料力学I-2)

Urethane Acrylates for D2T2 Printing System

The D2T2 (Dye Diffusion Thermal Transfer) printing system, which is famous in video printers, is used widely because of its gradation sequence and instancy. In this printing system, sublimation dye on the ink ribbon is transferred and spread into the receptive layer resin by heat from the thermal head. Since optical density depends on the glass transition temperature (Tg) of receptive layer resin, for high optical density we have to use low Tg resin for the receptive layer. However, when the resin with low Tg is used as the receptive layer resin, the stick-slip behavior becomes worse because the frictional coefficient is high. So, adjustment of the optical density and stick-slip behavior is important.We have found that UV/EB curable urethane acrylates that consist of the low molecular weight diols (glycols) are useful material to resolve these opposite properties. And we have studied the relationship between the kind of glycols and the properties of the receptive layer resin.

Analysis of Contact Pressure Acting on a Thermal Print Head of a Thermal Transfer Printer

The printing method of the thermal transfer printer is to push an ink ribbon that is heated and melted by a thermal print head to a printing paper, and transfer the ink desired positions on the paper. Thus it is important to place the heater of the thermal print head at the position where the contact pressure is most high. The visco elastic properties of the ink, PET and platen rubber were measured with a rheometer. The contact pressures on the thermal print head were calculated by FEM. The contact pressures under consideration of visco elasticity were different from those calculated by elastic analysis. The effect of sliding speed of the thermal print head on the contact pressures was also examined. To examine the effect of the contact pressure on the print quality the optical densities were measured with the heater positions of the thermal print head changed. The optical densities were changed with the heater positions. It can be found that the optical densities decreased with the calculated contact pressure.

The Forensic Analysis of Thermal Transfer Printing

Thermal transfer printing refers to printing processes that utilize heat to produce an image by either physical or chemical means or by a combination of both. As the technology has improved and the supplies have become less expensive, the use of thermal printing in the personal and business markets has increased significantly. Specifically, dye diffusion thermal transfer and thermal mass transfer have become predominant in the production of counterfeit credit cards, drivers' licenses, and other types of documents produced on plastic media. Chemical analysis by means of thin layer chromatography (TLC) has proven to be useful in characterizing various types of inks (e.g., writing and inkjet inks). In this study, the authors examined 81 different samples that included a total of 54 printer samples (43 photographic prints on paper and eleven plastic card samples) and 27 printer ribbons. A new TLC method was developed and tested utilizing a solvent system (80% n-hexane, 3% methyl ethyl ketone, and 17% ethyl acetate) that is capable of producing excellent resolution.

Study of High Definition Full Color Imaging to Plain Paper by Thermal Transfer Printing

We have analyzed the thermal transfer printing process and 600 dpi high definition thermal transfer ink ribbons. The results of our analysis revealed that four factors would play an important role in high definition thermal transfer ink ribbons: (1) the rupture strength of the ink under printing pressure and temperature, (2) the adhesive strength between the ink and paper, (3) thickness of the ink layer and (4) the adhesive strength between the heated ink and the base film. We have used a quantitative model for the printing process to design an improved ink ribbon, and we describe measurements of the viscoelastic characteristics which were used to optimize the ink materials. The improved 600 dpi high definition full color thermal transfer ink ribbon has a base of 2.5 μm polyethylene terephthalate (PET). The ink comprises two layers; a 1.3 μm ethylene-vinyl acetate copolymer thermoplastic resin and a release layer of 0.9 μm wax.

Print-head actuator used in product identification systems

In this paper, various factors affecting the operation of an electromagnetic actuator used in thermal transfer printers are being investigated. The magnetic and electromechanical performance of these devices were optimised. New improved actuator geometries were implemented, and compared with the commercially available design to improve it. The need for using laminated cores to enable fast operation is discussed and such a core is built and tested. It is also shown how the print speed can be increased from 2400 to 3540 labels/min, by changing the geometry of the actuator, as well as by choosing the most suitable magnetic material. It is demonstrated how the best geometry of the actuator can be achieved with the aid of finite element computer packages. Three print-head actuators are compared to a commercial design and conclusions are drawn for the best geometry and magnetic material.

1.0 W High-Power Small-Sized Nd: Yttrium Aluminum Garnet (YAG) Laser Optical Head for a Laser-induced Printing System

A high-power small-sized optical head which adopts a laser diode (LD) pumped Nd: yttrium aluminum garnet (YAG) laser (maximum power: 16 W) for a laser-induced thermal-transfer printing system was developed. The size of the developed optical head is 10 cm (width) × 15 cm (depth) × 3 cm (height); the maximum power of an optical spot that can be obtained is 1.2 W. Stable characteristics of pulse width modulation and rise-time using the acousto/optic modulator (AOM) are confirmed experimentally. Digital high-definition image printing was evaluated at the 3 µs laser pulse by the developed head. The system achieved a more than 10-fold speed increase over our previous system which adopted a 100 mW laser diode. In addition, a good high-definition digital image was confirmed. In this paper, we describe the optical design and optical characteristics of the high-power small-sized optical head, which adopts a laser diode pumped Nd:YAG laser; we also present experimental results of the digital high-definition image.