Exploring The Inspection Technique In The Sequence Of Uncrossed Laser Printed And Handwriting Words

Laser printers are the most commonly used printers in modern offices.In the field of Document Identification,the number of cases involving the sequence identification of laser printed and handwriting words has also increased rapidly,including the sequence of uncrossed laser printed and handwriting words.At present,there is no effective testing method for such cases.The sequence identification of uncrossed laser printed and handwriting words has become one of the most difficult problems in the field of Document Identification.There is very little research on this issue at home and abroad.Existing researches haven't explored effective testing methods or stable and unambiguous features to distinguish the uncrossed sequence of laser printed and handwriting words.The research on this issue is difficult and incomplete,with few research achievements.This thesis takes new approaches to explore the the sequence of uncrossed laser printed and handwriting words,which can be divided into five parts:The first chapter is the theoretical basis of the sequence identification of uncrossed laser printed and handwriting words.The first section analyzed the working principle of laser printers,divided sign pens into gel ink pens,oil-based ink pens,carbon ink pens and fountain pens,and analyzed the ink composition of each kind of pens.The second section described the theory of sequence identification of uncrossed laser printed and handwriting words.Then systematically enumerated the inspection methods,including traditional methods and methods used in this thesis.Chapter 2 uses stereo microscope to observe microscopic morphology of writing strokes and the relationship between toners and handwriting ink.Found:(1)Through the change of ink gloss and three-dimensional degree of writing strokes can distinguish the sequence of uncrossed laser printed words and strokes written with gel ink and oil-based ink pens,but can not distinguish the sequence of uncrossed laser printed words and strokes written with carbon ink and fountain pens.(2)When there is more ink in strokes,it can be easier to identify the sequence of uncrossed laser printed and handwriting words by changes in the sense of ink stacking and gradation.(3)At different sequences,the intersections of laser printed strokes and strokes written with gel ink and oil-based ink pens are very different,but similar when strokes are written with fountain pens.(4)It is more difficult to find a single toner in strokes written after printing,some toners are fused and some are semi-fused with stronger reflection.In samples printing after written,it is easier to find toners on the strokes in a semi-fused state and the color of toners is darker.(7)Different laser printers,pens,writing strength,writing backing,writing postures,etc.will affect the results of inspection.Chapter 3 uses microspectrophotometer to detect the chromatic aberration between writing strokes and paper,to identify the the sequence of uncrossed laser printed and handwriting words by changes of chromatic aberrations.Found through experiments:(1)The chromaticity of the paper will change after it passing the laser printer.(2)The chromatic aberration between strokes written with gel ink and oil-based ink pens and paper has decreased after passing the laser printer,and the change is smaller when use some special ink,such as MIKUNI and UNI.The chromatic aberration between strokes written with carbon ink pens and paper has no change after passing the laser printer.After passing the laser printer.As for chromatic aberration between blue-black ink pens and paper,no firm conclusion can be drawn due to the limited number of sample in this experiment.(3)The use of microspectrophotometry will be influenced by uneven distributed ink and paper fiber.Choose proper sampling points and sampling area can reduce the impact of these two factors.Chapter 4 is the research of application of experimental results,analyzed through a typical case,then summarized the main points and precautions of the sequence identification of uncrossed laser printed and handwriting words.The fifth chapter is summary and prospect.The inspection techniques used in this thesis are feasible for the identification of the sequence of uncrossed laser printed andhandwriting words.To some extent,the experimental results have filled theoretical gaps in this field,provide new research directions and also have positive guidance and promotion functions in Document Identification practice.In the future,we can do more in-depth research on this subject and study how to put the experimental results into solve real cases.