| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 34.69 MB | Adobe PDF |
Advisor(s)
Abstract(s)
Apesar da impressão inkjet ser ainda um processo de impressão relativamente
recente, actualmente já domina sobre todos os outros processos de impressão digital,
quer nos escritórios, quer nos lares de todo o mundo. O papel é o material mais
utilizado na impressão. Associado ao crescimento e desenvolvimento tecnológico da
impressão inkjet, surgiu também o aumento das exigências relativamente às
características do papel. Em termos de relação qualidade / custo, existe uma grande
diferença entre o papel para impressão comum, o qual é relativamente barato mas não
oferece elevada qualidade de impressão, e o papel com qualidade fotográfica que
permite impressões com elevada qualidade, mas apresenta custos bastante elevados.
Deste modo, a modificação da superfície do papel com o objectivo de optimizar a
relação qualidade de impressão / custo é uma área de investigação com especial
interesse para a indústria de papel.
O presente trabalho tem como objectivo estudar a modificação da superfície do
papel ao nível físico-químico e avaliar o desempenho do papel modificado no processo
de impressão inkjet.
A modificação da superfície do papel consistiu no processo de colagem
superficial, aplicando diferentes formulações produzidas a partir de vários produtos
comerciais, sendo estes divididos em três categorias: colas, aditivos e pigmentos.
A caracterização do papel modificado ao nível da permeabilidade ao ar,
topografia de superfície e das propriedades ópticas, mostrou que estas propriedades
são determinadas principalmente pelo papel base. A energia de superfície dos papéis
e as respectivas componentes polar e dispersiva, dependem da composição da
formulação, ou seja, do tipo de cola utilizada, dos aditivos e dos pigmentos.
Os vários papéis produzidos foram impressos na impressora HP Deskjet F370
com um padrão de impressão. Posteriormente, avaliaram-se os seguintes parâmetros
técnicos de qualidade de impressão: capacidade de reprodução de cor (área gamut e
densidades ópticas de impressão), qualidade de impressão das linhas (largura,
raggedness, blur e inter color bleed) e dos pontos preto e magenta (circularidade e
ganho).
Although inkjet printing process is relatively new, nowadays it is the dominant digital printing process in offices and homes around the world. Paper is the most used material for printing. Demand for inkjet paper has increased sharply as inkjet printing technology advanced. Concerning the quality/cost relationship, a gap exists between plain paper, which has a low cost but doesn’t produce a high printing quality, and photo paper, which offers high quality inkjet printing but has a high cost. So, paper surface modification for printing quality/cost ratio optimization is a research area with special interest to the paper industry. The purpose of this work is to study paper surface modification at a physicalchemistry level and to evaluate the performance of the modified paper on the inkjet printing process. The surface modification consists of the surface sizing process with application of different formulations made from a wide range of commercial chemicals which are divided in three classes: adhesives, additives and pigments. The characterization of the modified paper in terms of air permeability, surface topography and optical properties showed that these properties are mainly determined by base paper. Paper surface energy and their polar and dispersive components depend on the formulation composition, i.e., type of applied adhesive, additives and pigments. The different produced papers were printed in the HP DeskJet F370 printer with a printing pattern. Subsequently, the following technical printing quality parameters were evaluated: color performance (gamut area and printing density), lines print quality (width, blur, raggedness and inter color bleed) and black and magenta dots print quality (circularity and gain). A paper with good printing quality must provide both high color performance and low values for line and dot printing quality parameters. In general terms, it can be said that the papers which best meet these requirements are those surface sized with formulations containing PVA or additive 1. At the end of this work, aiming the visualization of differences amongst samples and establishing relationships between physical / physical-chemistry parameters and printing quality technical parameters, the principal component analysis was made. Additionally, the multivariable regression permitted the obtaining of models relating variables. Several correlations between printing quality technical parameters and physical / physical-chemistry parameters were established. It was found that black printing density depends of surface energy and air permeability, while magenta printing density depends primarily on the air permeability and the presence or absence of high peaks and deep valleys abnormally distributed on the surface. The line width depends on surface energy and surface roughness.
Although inkjet printing process is relatively new, nowadays it is the dominant digital printing process in offices and homes around the world. Paper is the most used material for printing. Demand for inkjet paper has increased sharply as inkjet printing technology advanced. Concerning the quality/cost relationship, a gap exists between plain paper, which has a low cost but doesn’t produce a high printing quality, and photo paper, which offers high quality inkjet printing but has a high cost. So, paper surface modification for printing quality/cost ratio optimization is a research area with special interest to the paper industry. The purpose of this work is to study paper surface modification at a physicalchemistry level and to evaluate the performance of the modified paper on the inkjet printing process. The surface modification consists of the surface sizing process with application of different formulations made from a wide range of commercial chemicals which are divided in three classes: adhesives, additives and pigments. The characterization of the modified paper in terms of air permeability, surface topography and optical properties showed that these properties are mainly determined by base paper. Paper surface energy and their polar and dispersive components depend on the formulation composition, i.e., type of applied adhesive, additives and pigments. The different produced papers were printed in the HP DeskJet F370 printer with a printing pattern. Subsequently, the following technical printing quality parameters were evaluated: color performance (gamut area and printing density), lines print quality (width, blur, raggedness and inter color bleed) and black and magenta dots print quality (circularity and gain). A paper with good printing quality must provide both high color performance and low values for line and dot printing quality parameters. In general terms, it can be said that the papers which best meet these requirements are those surface sized with formulations containing PVA or additive 1. At the end of this work, aiming the visualization of differences amongst samples and establishing relationships between physical / physical-chemistry parameters and printing quality technical parameters, the principal component analysis was made. Additionally, the multivariable regression permitted the obtaining of models relating variables. Several correlations between printing quality technical parameters and physical / physical-chemistry parameters were established. It was found that black printing density depends of surface energy and air permeability, while magenta printing density depends primarily on the air permeability and the presence or absence of high peaks and deep valleys abnormally distributed on the surface. The line width depends on surface energy and surface roughness.
Description
Keywords
Impressão inkjet - Papel Impressão inkjet - Tinta