Search results
1 – 10 of 36Ashok V. Kumar, Anirban Dutta and James E. Fay
A solid freeform fabrication (SFF) technique is described where powder is deposited layer‐by‐layer using electrophotographic printing. In the electrophotography process, powder is…
Abstract
A solid freeform fabrication (SFF) technique is described where powder is deposited layer‐by‐layer using electrophotographic printing. In the electrophotography process, powder is picked up and deposited using an electrostatically charged surface. A test bed was designed and constructed to study the application of electrophotography to SFF. It can precisely deposit powder in the desired shape on each layer. A polymer toner powder was used to build small components by thermally fusing each layer of printed powder using a hot compaction plate. The feasibility of 3D printing using this approach was also studied by printing a binder powder using electrophotography on to a part powder bed.
Details
Keywords
Ashok V. Kumar and Anirban Dutta
A method for rapid prototyping based on electrophotographic powder deposition was investigated to study its potentials and to identify design and implementation challenges. This…
Abstract
A method for rapid prototyping based on electrophotographic powder deposition was investigated to study its potentials and to identify design and implementation challenges. This technique is referred to here as the electrophotographic rapid prototyping (ERP). In this technique, powder is printed layer‐by‐layer in the shape of the cross‐sections of the part using electrophotography a very widely used non‐impact printing method. Each layer of powder is consolidated by fusing before the next layer of powder is printed. A fully automated test bed was constructed that consists of a printing system, fusing/heating plate, build platform that has two‐degrees of freedom as well as software that drives the system.
Details
Keywords
P. ELLIS, G. HEPBURN and C. OPPENHEIN
Work is described on patent citation networks, a novel technique for displaying the history of technological subjects and their key turning points. The method accurately…
Abstract
Work is described on patent citation networks, a novel technique for displaying the history of technological subjects and their key turning points. The method accurately identifies the key patents in a subject field, and if a subject docs not have a definite starting point, this is reflected in the patent network. The networks are less satisfactory if the key patent took a long time to appear in print. Subjects studied were: semi‐synthetic penicillins, tobacco substitutes, electrophotography, Ziegler‐Natta catalysis, and hovercraft. Possible uses of the technique are examined.
Matthew James Benning and Kenny Dalgarno
This paper aims to develop and then evaluate a novel consolidation and powder transfer mechanism for electrophotographic 3D printing, designed to overcome two longstanding…
Abstract
Purpose
This paper aims to develop and then evaluate a novel consolidation and powder transfer mechanism for electrophotographic 3D printing, designed to overcome two longstanding limitations of electrophotographic 3D printing: fringing and a build height limitation.
Design/methodology/approach
Analysis of the electric field generated within electrophotographic printing was used to identify the underlying causes of the fringing and build height limitations. A prototype machine was then designed and manufactured to overcome these limitations, and a number of print runs were carried out as proof of concept studies.
Findings
The analysis suggested that a machine design which separated the electrostatic powder deposition of the print engine from the layer transfer and consolidation steps is required to overcome fringing and build height limitations. A machine with this build architecture was developed and proof of concept studies showed that the build height and fringing effects were no longer evident.
Research limitations/implications
Electrophotography (EP) was initially seen as a promising technology for 3D printing, largely because the potential for multi-material printing at high speed. As these limitations can now be overcome, there is still potential for EP to deliver a high-speed 3D printing system which can build parts consisting of multiple materials.
Originality/value
The analysis of EP, the new method for the transfer and consolidation of layers and the proof of concept study are all original and provide new information on how EP can be adopted for 3D printing.
Details
Keywords
Zahra Bazrafshan, Maryam Ataeefard and Farahnaz Nourmohammadian
This paper aims to report on production of the colour digital printing toners cyan, magenta and yellow. Colour digital electrophotographic printing is currently in high demand…
Abstract
Purpose
This paper aims to report on production of the colour digital printing toners cyan, magenta and yellow. Colour digital electrophotographic printing is currently in high demand. The provision of a large colour gamut depends on appropriate selection of precise colourants to produce toner capable of producing a thin layer on paper.
Design/methodology/approach
Printing toners were synthesised by the emulsion aggregation method, and then evaluated for chemical constitution and effects of the colourant substituents.
Findings
Results demonstrated that increasing the polarity of a pigment produced better dispersion and lower particle size with narrower distribution and even better colour reproduction. While, changing a pigment’s characteristics did not affect the toner shape or its thermal properties.
Practical implications
The developed method provides a simple way to synthesise colour printing toner.
Social implications
Emulsion aggregation toners provide less hazardous materials during printing.
Originality/value
Evaluations of the influence of solid-state parameters and physicochemical properties of the pigments on printing toner characteristics were done for the first time.
Details
Keywords
Yayue Pan, Abhishek Patil, Ping Guo and Chi Zhou
Polymer-particle composites, which have demonstrated wide applications ranging from energy harvesting and storage, biomedical applications, electronics and environmental sensing…
Abstract
Purpose
Polymer-particle composites, which have demonstrated wide applications ranging from energy harvesting and storage, biomedical applications, electronics and environmental sensing to aerospace applications, have been investigated for decades. However, fabricating polymer-particle composites with controlled distribution of particles in polymer continues to be a fundamental challenge. As to date, a few additive manufacturing (AM) technologies can fabricate composites, however, with a limited choice of materials or limited dispersion control. Against this background, this research investigated a hybrid polymer-particle composite manufacturing process, projection electro-stereolithography (PES) process, which integrates electrostatic deposition and projection based stereolithography (SL) technologies.
Design/methodology/approach
In PES process, a photoconductive film collects charged particles in the regions illuminated by light. Then, collected particles are transferred from the film to a polymer layer with defined patterns. Lastly, a digital mask is used to pattern the light irradiation of the digital micromirror device chip, selectively curing the photopolymer liquid resin and particles of that layer. By transferring particles from the photoconductive film to the photopolymer in a projection-based SL system, multi-material composites with locally controlled dispersions could be produced. A proof-of-concept PES testbed was developed. Various test cases have been performed to verify the feasibility and effectiveness of the developed approach.
Findings
Challenges in this novel AM process, including process design, particle patterning and transferring, are addressed in this paper. It is found that particles can be transferred to a layer of partially cured resin completely and accurately, by using the stamping approach. The transferring rate is related to stamping force and degree of conversion of the recipient layer. The developed hybrid process can fabricate polymer-particle composites with arbitrary dispersion pattern, unlimited printable height and complicated geometries.
Originality/value
Although an electrostatic deposition process has been investigated as a 3D printing technology for many years, it is the first attempt to integrate it with projection SL for fabricating multi-material polymer composite components. The novel hybrid process offers unique benefits including local dispersion control, arbitrary filling patterns, wide range of materials, unlimited printable height and arbitrary complicated geometries.
Details
Keywords
Wesley L. Harris and Jarunee Wonglimpiyarat
This study aims to explore the strategies of Xerox Corporation (Xerox) in the copier industry, as its inception to date. In particular, it examines the process of Xerox’s creating…
Abstract
Purpose
This study aims to explore the strategies of Xerox Corporation (Xerox) in the copier industry, as its inception to date. In particular, it examines the process of Xerox’s creating platform advantage (the capability to engender an increasing future and continuing success of new innovations or businesses). The study provides insights on Xerox’s pursuit of specific strategies in managing technological innovations in the midst of fierce market competition.
Design/methodology/approach
The research study uses a case study methodology to explore the strategic foresight of Xerox servitization. The study develops the new methodological tool to analyse the process of technology platform and business platform creation. The model can be applied to any industry to understand the pursuit of strategies in high-tech based market competition.
Findings
The analyses of Xerox’s strategies, as its inception to date, have revealed the process of platform creation (technology platform and business platform), which enabled Xerox to enjoy a continuing advantage. The results have shown that the pursuit of specific strategy is motivated by risk considerations as much as by a search for profit. Xerox has continually upgraded its platforms to get ready for the competition under the digital transformation of servitization.
Originality/value
The main contribution of this research study is the development of a new methodological framework, which can be used to analyse the process of platform creation in any industry. The new framework introduces a dynamic concept (rather than a static concept generally found in the previous literature) of technology and business platforms. This research study contributes to the body of knowledge in the areas of strategic management of innovation.
Details
Keywords
Shenmeng Xu, Xianwen Wang, Zeyuan Liu and Chunjuan Luan
– The purpose of this paper is to analyze the network structure of technology in and between different fields, as well as the evolution of their relations.
Abstract
Purpose
The purpose of this paper is to analyze the network structure of technology in and between different fields, as well as the evolution of their relations.
Design/methodology/approach
Using the patent data in Derwent Innovation Index (DII) from 1991 to 2010, this paper analyzes the co-classification of Derwent Manual Code (DMC) of patents in all technology fields. Large-scaled co-classification matrices are employed to generate the DMC co-classification networks. In addition, analyses are pursued at different levels of aggregation in four five-year windows: 1991-1995, 1996-2000, 2001-2005 and 2006-2010. Using Girvan-Newman algorithm in the clustering process, the structure transformations over time are detected.
Findings
The paper identifies the key technological knowledge in certain fields and finds out how different technological fields are connected and integrated. What is more, the dynamic evolution between networks in different time periods reveals the trend of generic technology development in the macroscopic level.
Originality/value
The paper investigates a large quantity of data – all the patent data in DII from 1991 to 2010 in this paper. The paper applies Girvan-Newman algorithm in the co-classification analysis and uses co-classification networks to reveal technology network structures. Evolution coincident with the realistic technological shifts can be observed.
Details
Keywords
This paper aims to investigate the effect of paper properties (whiteness, gloss and roughness) on colour laser printing quality. Paper characteristics have a significant influence…
Abstract
Purpose
This paper aims to investigate the effect of paper properties (whiteness, gloss and roughness) on colour laser printing quality. Paper characteristics have a significant influence on print quality and are crucial variables for predicting and reproducing colour.
Design/methodology/approach
Six kinds of paper with different properties were selected and the effects of the paper characteristics on the printed paper were studied. Samples were printed with cyan, magenta and yellow toner with a laser printer under identical conditions. The papers and printed papers were evaluated with atomic force microscope, scanning electron microscope, gloss-meter, spectrophotometer and densitometer.
Findings
Results showed that print quality is statistically dependent on paper type, and the average optical density of printed paper varied for different papers. Furthermore, the increase in the roughness and gloss of the papers in comparison to whiteness more significantly affected the optical density of paper by reducing it.
Practical implications
To achieve high-quality print, laser printing paper and toner require controlled characteristics.
Originality/value
For the first time, the present study evaluated the influence of paper properties on the quality of colour laser printing.
Details
Keywords
Fatemeh Andami, Maryam Ataeefard, Farhood Najafi and Mohammad Reza Saeb
Printing toners are polymer composites accountable for transmission of digital images onto target substrates. Bearing in mind the ever increasing demand for high quality digital…
Abstract
Purpose
Printing toners are polymer composites accountable for transmission of digital images onto target substrates. Bearing in mind the ever increasing demand for high quality digital printing, modification and/or integration of existing techniques for manufacturing toners with favourable morphological and colour characteristics appears of vital importance. The present study aims to uncover the significance of in-situ polymerisation method, i.e. suspension, emulsion and mini-emulsion to control the microstructure of toner particles (particle size, particle size distribution and sphereness) while keeping the energy required for polymerisation along with reaction conversion at a reasonable level.
Design/methodology/approach
Assessment of particle size, particle size distribution and reaction conversion visualised the potential of suspension, emulsion and mini-emulsion polymerisation techniques to control microstructure, and colour characteristics of synthesized toners as well.
Findings
The results provided support for the fact that either the emulsion or mini-emulsion polymerisation routes will result in toners having an acceptable particle size and particle size distribution in the presence of a redox precursor. The higher monomer conversion at low temperature, as compared to the suspension polymerisation, was noticeable.
Practical implications
Analysing the glass transition temperature and colour characteristics of the resulting toners elucidated the superiority of mini-emulsion with respect to the other two cases which ranks this method on account of application.
Originality/value
For the first time, mini-emulsion route was put into practice and toners with acceptable colour and microstructure features were synthesised. In spite of lower polymerisation temperature and higher conversion of mini-emulsion compared to suspension and emulsion polymerisation techniques, further investigations are required to fine-tuning the properties of toners produced through this method.
Details