PhD

PhD

Revisions made by tamc up to 02:26 Fri 16 Nov 2007

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02:26 Fri 16 Nov 2007

  1. 0. I've finished my PhD. It was supervised by [[ Julian
  2. 1. Allwood => http://www.ifm.eng.cam.ac.uk/people/jma42]] and my thesis was titled:
  3. 0. I've finished my PhD. It was supervised by [[ Julian Allwood => http://www.ifm.eng.cam.ac.uk/people/jma42]] and my thesis was titled:

02:25 Fri 16 Nov 2007

  1. 0. I've finished my PhD. It was titled:
  2. 0. I've finished my PhD. It was supervised by [[ Julian
  3. 1. Allwood => http://www.ifm.eng.cam.ac.uk/people/jma42]] and my thesis was titled:

02:22 Fri 16 Nov 2007

  1. 55. # A high resolution (70MB) copy will be uploaded soon.

02:16 Fri 16 Nov 2007

  1. 0. I've finished my PhD. It was on:
  2. 0. I've finished my PhD. It was titled:
  3. 52.
  4. 53. You can download a pdf:
  5. 54. # [[ Low resolution (5MB) => http://www.counsell.org/tamc-removetonerreusepaper-small.pdf ]]

02:15 Fri 16 Nov 2007

  1. 0. My PhD topic is ...
  2. 0. I've finished my PhD. It was on:
  3. 2. h1. Can we build a Desktop Paper Recycling Machine?
  4. 2. h1. Remove toner: Reuse paper
  5. 4. Many products are consumed or destroyed in use. Office paper is not. In use it gains a surface coat of print and is only occasionally torn or holed. This raises some interesting recycling possibilities. The one considered here is whether we can build a machine that could recycle paper on the desktop.
  6. 4. _Thomas A. M. Counsell_
  7. 6. Office paper has three major environmental impacts: methane emissions when it is land-filled, carbon-dioxide emissions from the energy needed to evaporate water in the manufacturing process and water pollution from the chemicals used in manufacturing.
  8. 6. h2. Abstract
  9. 8. Recycling office paper is preferable to virgin production but not ideal. It uses half the energy, and produces between half and three quarters of the water and air pollution. However the first step in paper recycling is to place the waste paper in water and mash it until the paper is reduced to a mass of tiny cellulose fibres. This step has three implications:
  10. 9. # Around forty percent of the original waste paper is rejected in the ink removal process because of the difficulty of distinguishing unwanted ink from the wanted paper additives and small cellulose fibres when the three are mixed in suspension.
  11. 10. # The subsequent re-forming and drying of the paper is energy intensive and
  12. 11. # Re-forming and drying damages the cellulose fibres, limiting their life.
  13. 12. These drawbacks, combined with the difficulty in collecting paper to be recycled from a large number of widely distributed and low volume uses, means that less than a fifth of Office Paper in Europe is recycled, and that that is tends to be turned into lower value papers such as newsprint and packaging where there is less need for perfect removal of ink.
  14. 8. This thesis reports on experiments into whether abra-
  15. 9. sives, lasers or solvents can remove ordinary black toner-
  16. 10. print from ordinary white office paper in a way that leaves
  17. 11. the paper reusable. If it could be ‘un-printed’ then waste
  18. 12. office-paper could be reused immediately, without the need
  19. 13. for recycling.
  20. 14. The hypothesis of this project is that it may be possible to overcome these problems by using a different approach to removing ink that does not damage the paper and could be operated within and office. A machine suitable for an office of about 70 people would need to be able to clean the print off about 1.5 tonnes of paper a year, at a rate of one sheet every minute and a half, at a total cost of less than �1400 a year (implying a maximum capital cost of around �7000).
  21. 15. Paper and board consumption causes approximately
  22. 16. 1% of man-made climate change gas emissions. Estimates
  23. 17. in the first chapter suggest that un-printing could reduce
  24. 18. emissions per tonne of office paper by up to 95% – greater
  25. 19. than the potential from incineration, localisation, annual
  26. 20. fibre, fibre recycling, un-printing or electronic paper.
  27. 16. Most office paper is laser printed or photocopied, which means that the print consists of between 10 million and a billion 0.005 to 0.025mm polyester spheres that have been impregnated with flecks of carbon black. These spheres have been heated and pressed onto the surface of the paper. The size and surface nature of toner print is likely to make it easier to remove than Ink jet and other print types that deposit tiny particles of pigment or dye deep in the paper fibres using a solvent (often water) that then evaporates away.
  28. 22. There has been no academic work on un-printing, but
  29. 23. some relevant patents have been filed. The second chapter
  30. 24. reviews these patents according to whether they remove,
  31. 25. obscure or de-colour the original print. It is not clear from
  32. 26. the patents whether toner-print can be removed by abra-
  33. 27. sives, lasers, or solvents without rendering the paper un-
  34. 28. usable. These three approaches are tested experimentally
  35. 29. and the results reported in chapters 3, 4 & 5.
  36. 18. The initial focus of the project is to remove toner print without damaging the paper. The removal of other print types and the repair of tears holes and folds in paper will be subsequent projects. There has been no published work in this area, although there have been around a hundred patent filings, particularly by Japanese photocopier manufacturers. There are two alternative approaches that achieve the same aim of recycling office paper but do not involve removing print; the print can be obscured (much like correction fluid) or the print could be made to become invisible (a product that does this has been launched by Toshiba in Japan). Obscuring print is not being considered because of the likely cost and impact of supplying the obscuring material and because of the build up of obscuring material is likely to limit the number of times the paper can be re-used. Making the print invisible is not being considered because it is also likely to lead to a build up in material limiting re-use and because it would require firms to change the type of toner they use.
  37. 31. Abrasives can remove toner-print with limited dam-
  38. 32. age to the underlying paper by operating in an adhesive
  39. 33. wear regime. This involves making ten passes with a fine
  40. 34. P800 abrasive rubbing at high speeds (6 m/s) and low loads
  41. 35. (0.3 N). Longer wavelength lasers are able to remove the
  42. 36. toner-print and leave blank paper undamaged by operating
  43. 37. at 1 W and 10 kHz in the 1064 nm wavelength and scanning
  44. 38. across the surface eight times at 400 mm/s. Unfortunately
  45. 39. the paper beneath the print is yellowed during removal.
  46. 40. A 40:60 mixture chloroform and dimethylsulfoxide effec-
  47. 41. tively dissolves toner without dissolving paper if agitated
  48. 42. with ultrasound for four minutes.
  49. 20. Four main methods are being considered to remove the print; abrading it, ablating it, peeling it using a sticky surface and dissolving it. The next year will be spent constructing experiments that allow the performance of these methods to be tested individually and in combination and to generate a greater public understanding of how the bond between print and paper might be broken.
  50. 44. Chapter 6 outlines the research required to make the
  51. 45. approaches feasible replacements for conventional paper re-
  52. 46. cycling. The abrasive approach requires research into ex-
  53. 47. tending abrasive life. The laser approach requires research
  54. 48. into avoiding paper yellowing. The solvent approach re-
  55. 49. quires research into benign solvents and solvent recycling.
  56. 50. All three approaches would need to be tested on a wider
  57. 51. range of prints and papers.
  58. 22. The work is funded by the Engineering and Physical Sciences Research Councill (EPSRC). Further information may be obtained from Tom Counsell (tamc2@cam.ac.uk) or in my publications.

07:34 Mon 03 Apr 2006

  1. 24. [[ insert my publications ]]
  2. 24. [[ insert publications ]]

07:34 Mon 03 Apr 2006

  1. 23.
  2. 24. [[ insert my publications ]]

09:42 Fri 03 Feb 2006

  1. 14. The hypothesis of this project is that it may be possible to overcome these problems by using a different approach to removing ink that does not damage the paper and could be operated within and office. A machine suitable for an office of about 70 people would need to be able to clean the print off about 1.5 tonnes of paper a year, at a rate of one sheet every minute and a half, at a total cost of less than 1400 a year (implying a maximum capital cost of around 7000).
  2. 14. The hypothesis of this project is that it may be possible to overcome these problems by using a different approach to removing ink that does not damage the paper and could be operated within and office. A machine suitable for an office of about 70 people would need to be able to clean the print off about 1.5 tonnes of paper a year, at a rate of one sheet every minute and a half, at a total cost of less than �1400 a year (implying a maximum capital cost of around �7000).
  3. 22. The work is funded by the Engineering and Physical Sciences Research Councill (EPSRC). Further information may be obtained from Tom Counsell (tamc2@cam.ac.uk) or in:
  4. 23. * Counsell and Allwood 2004,A Review of Technology Options for Reducing the Environmental Impact of Office Paper, Submitted to Resources, Conservation and Recycling.
  5. 22. The work is funded by the Engineering and Physical Sciences Research Councill (EPSRC). Further information may be obtained from Tom Counsell (tamc2@cam.ac.uk) or in my publications.
  6. 24. * Counsell and Allwood 2004, Desktop Paper Recycling: A survey of novel technologies that might recycle office paper within the office, Submitted to the Journal of Materials Processing Technology.
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