Research of influencing factors on the change of geometric parameters of Braille elements on self-adhesive labels/Lipniose etiketese suformuoto brailio rasto geometriniu parametru dydzius itakojanciu faktoriu tyrimai.
Havenko, S. ; Labetska, M. ; Stepien, K. 等
1. Introduction
The adaptation of blind people in their daily lives --it is an
important socio-humanitarian and economic problem, the relevance of
which requires the search for new technologies to improve the process of
printing information in Braille on labels and packaging used by blind
people. Therefore, in this document main attention is focused on the
study of the influence of technological factors and regime of digital
printing to form Braille relief-dot elements.
The main purpose of Braille--is creating a comfortable environment
for people with weak or completely absent vision in communication in
commerce, social networks and more. According to international
requirements (Directive of the European Parliament and of the Council
2004/27/ES from 31.03.2004) in the pharmaceutical industry for drugs
along with the usual text is mandatory description of the product in
Braille [1, 2]. Obviously, labeling in Braille in the future will be
mandatory for manufacturers of food and chemical industries.
The Braille can be formed on self-adhesive labels which are widely
used for various purposes and types packages. Self-adhesive label
consists of a surface coating paper or synthetic base layer of adhesive
and substrate (Fig. 1). The choice of material and technology of causing
the image on the stick depends on the destination and its area of use
[3].
The high-quality tactile images for the blind people can be made
with regard to the relevant assessment criteria in Braille, in
particular: the relief height, profile characteristic element, adhesion
of relief items to the base material, abrasion resistance and peel under
the fingers, durability, and tactile sensations [4].
[FIGURE 1 OMITTED]
The relief images designed for "scanning" by fingers of
blind persons can be made by using different technological variants. It
should be taking into account length runs, the mechanization of
manufacturing operations, production costs, the time required to print
one copy, when choosing the technology of creating relief-dot elements.
Analytical review of scientific publications and patent searches
conducted technical solutions [5-9] allowed us to develop a detailed
classification of methods of applying image labeling for the blind
people. For printed relief images are used:
Contact methods:
* stamping on cardboard (corrugated board), special types of paper
and films by stamps;
* screen printing on special paper with thick layers of paint that
does not flow, or composition, creating relief on the plane due to
thermal imprint;
Non-contact methods (digital printing):
* ink-jet printing with special varnish composition;
* methods of getting relief images using polymer and other thermo
chemical materials on laser printers.
The choice of a reproduction technology depends on the scope,
purpose, categories of users and available resources. However,
experience shows that the need for significant investment is the first
and perhaps the most important problem in implementing inscriptions in
Braille.
The analysis shows that today's printing market is dominated
by two methods of reproduction of information for blind people. The
first is the formation of relief items by stamping and is more common in
European countries through a number of advantages with regard to the
cost of the order and speed of its implementation. But despite its
popularity, this technology has significant disadvantages, namely:
restrictions in height of Braille relief-dot elements, not always
satisfactory requirements for mechanical strength, which leads to a
decrease bump in the operation of such texts by blind people. Widespread
technology of reproduction of information for blind people is a screen
printing method, which can be implemented on a variety of
materials--paper, cardboard, film and more. Moreover, the use of this
method provides significant resistance relief items to mechanical
influence during transport and reading by blind people.
Becoming popular digital printing thus relief-dot images can be
implemented on a self-adhesive label. One of the most innovative and
flexible solution is digital inkjet printing when the Braille dots are
printed using high viscosity transparent UV dried varnish on various
materials. Quality of items Braille printed on self-adhesive label
depends on technological (physical and mechanical properties of the
substrate and varnish) and operating conditions (temperature and
pressure of varnish, substrate feed rate) factors that require detailed
studies for getting quality tactile images. Printing Braille with
ink-jet, varnish viscosity and printing material surface stresses have
effect to Braille dot size [10-12].
The Braille printing on self-adhesive labels using digital print
still lack studies. Thus the aim of this paper is to determine optimal
values of printing speed and varnish temperature and the dot peel force
when Braille is formed under different technological regimes on various
materials.
2. Experiment equipment and method
The objects of research were images in Braille, created by digital
ink-jet printing machine Braillemaker One Convertec with special
transparent varnish Braille Maker Varnish 1.0 A. (see Table 1).
Transparent and clear Braille dots can be printed on various materials
(Top-coated PE, PA, PET, Alu., Paper, Carton, Silicone free varnished
substrates) using this printing machine. The Braille dots of
1.40-2.00x[10.sup.-3] m diameter and 0.20-0.40 x[10.sup.-3] m height
Braille dots This printing machine ensures the accuracy of printing of
Braille elements (tolerance with in the Braille dots [+ or -] 0,10 mm,
tolerance between blocks [+ or -] 0,15 mm) [13, 14].
The samples were printed with variable printing modes (temperature
(from 51 to 59[degrees]C) and pressure of varnish (from 2.0x[10.sup.5]
to 3.0x[10.sup.5] Pa), substrate feed rate (from 0.25 to 0.75 m/s) on 2
different self-adhesive labels (substrates), a width of 76.00
x[10.sup.-3] m: a) paper PrimeCoat MC S2000 (a white, one side machine
coated, wood free printing paper with semi-gloss appearance with basis
weight 80 g/[m.sup.2]); b) polyethylene film FASSON PE85 WHITE
S692N-BG40WH (a blown, corona-treated white polyethylene film with
medium gloss appearance with basis weight 82 g/[m.sup.2]).
For estimation of geometric parameters, obtained relief-dot
elements when changing technological conditions of deposition was used
metering devices FlexoCam (Fig. 2) [15] and a digital microscope
IntelPlay QX3 [16]. The FlexoCAM solution consists of the 24-bit RGB
camera with a resolution of 640x480 pixels which assistance takes a 3D
view of dot structures and halftone dot readings. Detailed color images
are viewed on a PC screen with the device linking directly via a USB
interface. The FlexoCAM is equipped with a coaxial light and a
three-array radial light source consisting of 16 LEDs which can be
switched on or off individually or in groups to achieve the optimum
illumination of the area to be measured.
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
To determine the resistance to peel of Braille characters using a
specially designed device (Fig. 3) that works as follows: the moving
plate with fixed scraper set in motion by the mechanism of tension,
which includes motors, reducers and switches; scraper element moves on
the surface of the device with prior fixed test sample; in the moment of
contact of scraper with the Braille element it is peel from the base of
surface (self-adhesive paper and film); the value of the pulling force
is fixing and transmitting by strain to personal computer.
3. Results and discussion
The analysis of the photomicrographs and topographies of Braille
dots surfaces (Fig. 4) has allowed to build graphical dependence (Fig.
5-6), which shows the relationship between geometric parameters
(diameter and height) relief-dot elements and technological modes of
printing:
* an increase the substrate feed rate from 0.25 to 0.75 m/s leads
to reduce dot's diameter from 1.62 x [10.sup.-3] m to 1.54 x
[10.sup.-3] m (on paper base), from 1.64 x [10.sup.-3] m to 1.56 x
[10.sup.-3] m (on polyethylene film) and to an increase its height from
0.19 x [10.sup.-3] m to 0.23 x [10.sup.-3] m (on paper base), from 0.20
to 0.23 x [10.sup.-3] m (on polyethylene film) ([t.sub.opt] =
59[degrees]C, [P.sub.opt] = 2.5x105 Pa);
* an increase varnish temperature from 51 to 59[degrees]C
accompanied by a decrease of its viscosity, causing a drop spreading and
increasing the dot's diameter from 1.56 to 1.58 x [10.sup.-3] m on
paper base and from 1.58 to 1.60 x [10.sup.-3] m on polyethylene film
and to an increase its height from 0.19 to 0.22 x [10.sup.-3] m (on
paper base), from 0.20 to 0.23 x [10.sup.3] m (on polyethylene film)
([V.sub.opt] = 0.58 m/s, [P.sub.opt] = 2.5 x [10.sup.5] Pa);
* the increase of pressure in the nozzle of varnish digital device
from 2.0 to 2.5 x [10.sup.5] Pa leads to reduce of Braille dots diameter
from 1.6 to 1.58 x [10.sup.-3] m (on paper base), from 1.62 to 1.60 x
[10.sup.-3] m (on polyethylene film) and to an increase its height from
0.18 to 0.22 x [10.sup.-3] m (on paper base), from 0.19 to 0.23 x 10-3 m
(on polyethylene film) ([t.sub.opt] = 59[degrees]C, [V.sub.opt] = 0.58
m/s). Further increasing the pressure to 3.0 x [10.sup.5] Pa does not
change geometrical parameters of Braille point.
[FIGURE 4 OMITTED]
Table 2 presents geometrical parameters of Braille obtained under
various technological regimes which are easy read by the blinds. Thus we
believe that are optimal. The optimal geometrical parameters were
determined carrying out mathematical-statistical analysis of obtained
data. It is determined that the findings of the experimental researches
meet the normal distribution law. The research data meet the equation of
this law:
[MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], (1)
where [sigma] is root-mean-square deviation; [x.sub.i] is the value
of separate finding; x is center of distribution (general average).
The analysis of experimental results, the estimated coefficient of
variation:
v=s/[bar.x]100, % (2)
where: s is standard deviation, x is the arithmetic average.
The coefficient of variation is 5% thus it can be stated that the
scattering of experimental findings is low.
As a result of investigation, the optimal values of geometrical
sizes of Braille dot are detected with the following technological
conditions: the substrate feed rate V = 0.58 m/s, the varnish
temperature t = 59[degrees]C, the pressure in the nozzle P = 2.5 x
[10.sup.5] Pa (Table 2). The results of experimental studies have shown
the influence of the material base for resistance to peel Braille dots
(the resistance to peel of dots on film base is 35 N, on paper base--32
N).
According to the researches of stability of images (Fig. 7),
recorded by digital microscopy, on samples with paper base, the peel of
the dots comes from the destruction of the structure of the surface
layers of self-adhesive paper and the peel of relief elements deposited
on the film base comes without damage to its structure (difference in
the peel strength is 3 N) (Table 3).
[FIGURE 7 OMITTED]
4. Conclusions
1. Conducted experimental researches of relief-dot elements,
digitally printed on self-adhesive label, allowed establishing the value
of their adhesion to the substrate and the dependence of geometric
parameters of Braille characters from technological and regime factors
of the printing process.
2. Investigated, that speed increase in the formation of relief-dot
image by digital printing leads to decrease in diameter and increase in
the height of the dot.
3. Braille parameters best read by the blinds were printed under
following regimes: substrate feed rate V = 0.58 m/s, the varnish
temperature t = 59[degrees]C, the pressure in the nozzle P = 2.5 x
[10.sup.5] Pa.
4. Optimal geometrical parameters of Braille printed on paper-based
self-adhesive labels are as follows: d = 1.58 x [10.sup.-3] m, h = 0.22
x [10.sup.-3] m, and polyethylene-based: d = 1.60 x [10.sup.-3] m, h =
0.23 x [10.sup.-3] m.
crossref http://dx.doi.org/10.5755/j01.mech.19.6.6016
Received January 15, 2013
Accepted December 10, 2013
References
[1.] Standard LST EN 15823:2010 Packaging--Braille on packaging for
medicinal products.
[2.] GOST R 50918-96 Brailles displays. General specifications.
[3.] Jakucewicz, S. 2004. Adhesive Materials, Warsawa, 136 p.
[4.] Douglas, G.; Weston, A.; Whittaker, J. 2008. Braille dot
height research: Investigation of Braille Dot Elevation on
Pharmaceutical Products, Final report 2008, University of Birmingham,
UK. http://www.education2.bham.ac.uk/documents/research
/VICTAR/Braille_Height.pdf.
[5.] Labetska, M.T. 2012. Analytical research of technological
features of thermographic printing, Book quality 1(21): 123-128.
[6.] Kibirkstis, E.; Venyte, I.; Lydekaityte, J. 2012. Resistance
to mechanical effect of Braille dot surface, formed on different
materials, VII International Scientific-Practical Conference Book
quality, June 6-8, 2012, Ukrainian Academy of Printing, Lviv, Ukraine:
144150.
[7.] Labetska, M.T.; Havenko, S.F. 2012. Research of performance
indicators of Braille relief-dot elements on packaging, I International
Scientific-Practical Conference Packaging industry: modern tendencies of
development and specialists training, Ukrainian Academy of Printing,
Lviv, Ukraine: 111-114.
[8.] Patent WO 96/41320 Touch-readable product and associated
process, 1996.
[9.] United States Patent 6 241 405 B1 Printer head for a Braille
printer and a method of manufacturing the same, 2001.
[10.] McCallum, D.; Ungar, S. 2003. An introduction to the use of
inkjet for tactile diagram production, The British Journal of Visual
Impairment 21(2): 73-77. http://dx.doi.org/10.1177/026461960302100206.
[11.] Creagh, L.T.; McDonald, M. 2003. Design and performance of
ink-jet printheads for non-graphics-arts applications, MRS Bull 11:
807-811. http://dx.doi.org/10.1557/mrs2003.229.
[12.] McCallum, D.; Ahmed, K.; Jehoel, S.; Dinar, S.; Sheldon, D.
2005. The design and manufacture of tactile maps using an inkjet
process, Journal of Engineering Design 16(6): 525-544.
http://dx.doi.org/10.1080/09544820500273946.
[13.] Braille Maker Varnish 1,0A for digital braille printing
<http://www.flintgrp.com/en/documents/Packagingand-Narrowweb/Narrowweb/I_07_05.pdf> Accessed 2013 Nov 19.
[14.] Braillemaker One specifications <http://www.matset.
com.tr/dosyalar/abg/braille/brosur/Braillemaker_One_2 009.pdfl>
Accessed 2013 Nov 19.
[15.] BrailleCAM for Braille dot inspection <http://www.
troika-systems.com/English/frames_FlexoCAM.html> Accessed 2012 Dec
10.
[16.] Intel Play QX3 microscope <http://micro.magnet.fsu.
edu/optics/intelplay/index.html> Accessed 2012 Dec 9.
S. Havenko, Ukrainian Academy of Printing, Pidholosko 19, 79020
Lviv, Ukraine, E-mail: havenko@point.lviv.ua
M. Labetska, Ukrainian Academy of Printing, Pidholosko 19, 79020
Lviv, Ukraine, E-mail: marta_motyka@mail.ru
K. Stepien, Technical University of Lodz, Skorupki 10/12, r. 105,
90-924 Lodz, Poland, E-mail: krzysztof.stepien@p.lodz.pl
E. Kibirkstis, Kaunas University of Technology, Studenty 56, 51424
Kaunas, Lithuania, E-mail: edmundas.kibirkstis@ktu.lt
I. Venyte, Kaunas University of Technology, Studenty 56, 51424
Kaunas, Lithuania, E-mail: ingrida.venyte@ktu.lt
Table 1
Physical and chemical properties of
Braille Maker Varnish 1.0 A
General information
Aggregate state liquid
Colour yellow
Odor characteristic
Specifications
Freezing Not Specified
Boiling point / range >100 [degrees]C
Ignition temperature 101 [degrees]C
Danger of explosion It is not explosive
Density at 20 [degrees]C 1.08 g/[cm.sup.3]
Stickiness at 23 [degrees]C 600-800 MPas
Solubility in water insoluble or sparingly soluble
Stability Stable under normal conditions
Table 2
Optimal Braille geometrical parameter values and the
printing technological regimes
Technological regimes Paper
Dots Dots
diameter, height,
d, x h, x
[10.sup.3] [10.sup.3]
m m
Substrate feed 0.58 1.58 0.22
rate V, m/s
Pressure in the 2.5 x
nozzle P, Pa [10.sup.5]
Varnish 59
temperature t,
[degrees]C
Technological regimes Polyethylene film
Dots Dots
diameter, height,
d, x d, x
[10.sup.3] [10.sup.3]
m m
Substrate feed 0.58 1.60 0.23
rate V, m/s
Pressure in the 2.5 x
nozzle P, Pa [10.sup.5]
Varnish 59
temperature t,
[degrees]C
Table 3
Braille dots resistance to peel at the optimal printing
technological regimes
Technological regimes Peel strength, [P.sub.st], N
Paper Polyethylene
film
Substrate feed rate V, 0.58
m/s
Pressure in the nozzle 2.5 x
P, Pa [10.sup.5] 32 35
Varnish temperature t, 59
[degrees]C
Fig. 5 Dependence of the Braille dot's diameter d from printing
technological regimes: a - from substrate feed rate V, when varnish
temperature t = 59[degrees]C, pressure in the nozzle P = 2.5 x
[10.sup.5] Pa; b - from varnish temperature t, when substrate feed
rate V = 0.58 m/s, pressure in the nozzle P = 2.5 x [10.sup.5]
Pa; c - from pressure in the nozzle P, when varnish temperature
t = 59[degrees]C, substrate feed rate V = 0.58 m/s
a
d, x [10.sup.-3] m
V, m/s paper base polyethylene film
0,25 1,62 1,64
0,42 1,60 1,62
0,58 1,58 1,60
0,75 1,54 1,56
b
d, x 10-3 m
t, [degrees]C paper base polyethylene film
51 1,56 1,58
59 1,58 1,60
c
d, x [10.sup.-3] m
P, x [10.sup.5] Pa paper base polyethylene film
2,0 1,60 1,62
2,5 1,58 1,60
3,0 1,58 1,60
Note: Table made from bar graph.
Fig. 6 Dependence of the Braille dot's height h from printing
technological regimes: a - from substrate feed rate V, when
varnish temperature t = 59[degrees]C, pressure in the
nozzle P = 2.5 x [10.sup.5] Pa; b - from varnish temperature
t, when substrate feed rate V = 0.58 m/s, pressure in the
nozzle P = 2.5 x [10.sup.5] Pa; c - from pressure in the
nozzle P, when varnish temperature t = 59[degrees]C, substrate
feed rate V = 0.58 m/s
a
h, x 10-3 m
V, m/s paper base polyethylene film
0,25 0,19 0,20
0,42 0,20 0,21
0,58 0,22 0,23
0,75 0,23 0,23
b
h, x 10-3 m
t, [degrees]C paper base polyethylene film
51 0,19 0,20
59 0,22 0,23
c
h, x [10.sup.-3] m
P, x [10.sup.5] Pa paper base polyethylene film
2,0 0,18 0,19
2,5 0,22 0,23
3,0 0,22 0,23
Note: Table made from bar graph.
