U.S. patent application number 10/944762 was filed with the patent office on 2005-04-28 for recycled plastic material, electronic apparatus having the recycled plastic material method of manufacturing plastic part, method of manufacturing the recycled plastic material, and method of reusing plastic material.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Akino, Shoji, Asakura, Osamu, Bungo, Takeshi, Iwasaki, Takeshi, Koike, Yasushi, Matsuhisa, Hirohide, Matsumoto, Mizuko, Uraki, Izumi.
Application Number | 20050090567 10/944762 |
Document ID | / |
Family ID | 26468851 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050090567 |
Kind Code |
A1 |
Koike, Yasushi ; et
al. |
April 28, 2005 |
Recycled plastic material, electronic apparatus having the recycled
plastic material method of manufacturing plastic part, method of
manufacturing the recycled plastic material, and method of reusing
plastic material
Abstract
A recycled plastic material is made from laser-engraved
thermoplastic, metal-containing thermoplastic, thermoplastic used
in an inkjet apparatus, or thermoplastic to which an ink or its
composition have stuck. This recycled plastic material is
manufactured by pulverizing any of these thermoplastics, cleaning
the pulverized thermoplastic, removing a cleaning solution from the
cleaned thermoplastic to dry it, and removing the dried
thermoplastic solid matter other than the thermoplastic.
Inventors: |
Koike, Yasushi;
(Kanagawa-ken, JP) ; Akino, Shoji; (Kanagawa-ken,
JP) ; Asakura, Osamu; (Kanagawa-ken, JP) ;
Matsumoto, Mizuko; (Kanagawa-ken, JP) ; Bungo,
Takeshi; (Tokyo, JP) ; Matsuhisa, Hirohide;
(Kanagawa-ken, JP) ; Iwasaki, Takeshi;
(Kanagawa-ken, JP) ; Uraki, Izumi; (Tokyo,
JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
CANON KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
26468851 |
Appl. No.: |
10/944762 |
Filed: |
September 21, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10944762 |
Sep 21, 2004 |
|
|
|
09564501 |
May 4, 2000 |
|
|
|
Current U.S.
Class: |
521/40 ; 521/41;
521/47 |
Current CPC
Class: |
B29B 2017/0203 20130101;
B29K 2071/12 20130101; B41J 29/02 20130101; B29K 2105/065 20130101;
Y02W 30/524 20150501; B29K 2025/00 20130101; B29B 17/0404 20130101;
B41M 5/24 20130101; B29K 2055/02 20130101; B29B 2017/0268 20130101;
Y02W 30/526 20150501; B29B 17/00 20130101; B29K 2023/12 20130101;
B29K 2705/00 20130101; B29B 2017/0224 20130101; Y02W 30/62
20150501; B41J 2/17503 20130101; B41J 2/17559 20130101; Y02W 30/52
20150501; B29B 2017/0241 20130101; B29K 2105/04 20130101; B29L
2031/767 20130101; B29B 2017/0289 20130101; Y02W 30/523 20150501;
B29B 2017/0244 20130101; B29B 17/02 20130101; B29B 2017/0272
20130101; Y02W 30/622 20150501; Y02W 30/625 20150501; Y02W 30/525
20150501; B29K 2075/00 20130101 |
Class at
Publication: |
521/040 ;
521/041; 521/047 |
International
Class: |
C08J 011/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 14, 1999 |
JP |
11-134867 |
Apr 18, 2000 |
JP |
2000-116965 |
Claims
1. (canceled)
2. A recycled plastic material manufactured by pulverizing
laser-engraved thermoplastic, cleaning the pulverized
thermoplastic, removing a cleaning solution from the cleaned
thermoplastic to dry the thermoplastic, and removing from the dried
thermoplastic solid matter other than the thermoplastic, wherein
letting I.sub.R and M.sub.R denote an Izod impact value and a melt
flow rate. respectively, of the recycled plastic material and
I.sub.V and M.sub.V denote an Izod impact value and a melt flow
rate of a virgin material of the thermoplastic before molding,
(I.sub.R/I.sub.V)>0.8 and (M.sub.R/M.sub.V)<1.2 are met.
wherein the cleaning solution is water, and water used in cleaning
is filtered and reused and a filter for filtering the water has a
mesh within the range of 25 to 200 .mu.m, and wherein a weight
ratio of the cleaning solution to the pulverized thermoplastic is
not less than 10 times.
3. (canceled)
4. A recycled plastic material manufactured by pulverizing
thermoplastic containing a metal, cleaning the pulverized
thermoplastic, removing a cleaning solution from the cleaned
thermoplastic to dry the thermoplastic, and removing from the dried
thermoplastic solid matter other than the thermoplastic, wherein
letting I.sub.R and M.sub.R denote an Izod impact value and a melt
flow rate, respectively, of the recycled plastic material and
I.sub.V and M.sub.V denote an Izod impact value and a melt flow
rate of a virgin material of the thermoplastic before molding,
(I.sub.R/I.sub.V)>0.8 and (M.sub.R/M.sub.V)<1.2 are met,
wherein the cleaning solution is water, and water used in cleaning
is filtered and reused, and a filter for filtering the water has a
mesh within the range of 25 to 200 .mu.m, and wherein a weight
ratio of the cleaning solution to the pulverized thermoplastic is
not less than 10 times.
5-20. (canceled)
21. A recycled plastic material manufactured by pulverizing
thermoplastic to which ink and components thereof have stuck,
cleaning the pulverized thermoplastic, removing a cleaning solution
from the cleaned thermoplastic to dry the thermoplastic, and
removing from the dried thermoplastic solid matter other than
thermoplastic, wherein letting I.sub.R and M.sub.R denote an Izod
impact value and a melt flow rate, respectively, of the recycled
plastic material and I.sub.V and M.sub.V denote an Izod impact
value and a melt flow rate of a virgin material of the
thermoplastic before molding, (I.sub.R/I.sub.V)>0.8 and
(M.sub.R/M.sub.V)<1.2 are met, wherein the cleaning solution is
water, and water used in cleaning is filtered and reused, and a
filter for filtering the water has a mesh within the range of 25 to
200 .mu.m, wherein a weight ratio of the cleaning solution to the
pulverized thermoplastic is not less than 10 times, and wherein an
amount of ink and components thereof sticking to the thermoplastic
after the solid matter is removed is less than 300 ppm.
22-26. (canceled)
27. The material according to claim 21, wherein the cleaning
solution used in cleaning is reused by a distillation
apparatus.
28-32. (canceled)
33. A recycled plastic material made from the material according to
claim 2, and a virgin material of thermoplastic before molding.
34. The material according to claim 2, wherein the thermoplastic is
one of an ABS resin, a PS resin, and a PS-modified PPE resin.
35-56. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a recycled plastic material
made from a thermoplastic product, an electronic apparatus using
this recycled plastic material a method of manufacturing a plastic
part, a method of manufacturing the recycled plastic material, and
a method of reusing a plastic material.
BACKGROUND OF THE INVENTION
[0002] Recently, with increasing consciousness of environmental
protection, the movement of recycling and reusing petrochemicals,
in addition to conventionally recycled metal materials, has become
active. Only in Japan territory, "Waste Disposal Law" (Law No. 137,
1970), "Law for Promotion of Sorted Collection and Recycling of
Containers and Packaging" (Law No. 112, 1995), and "Law for
Recycling of Specific Household Appliances" (Law No. 97, 1998) have
been enforced. As these laws and regulations have been enacted,
recycling of thermoplastics of some large household appliances and
automobiles has been accelerated.
[0003] Many of these recycling activities, however, are thermal
recycling using thermoplastics as a heat source and recycling for
cascade use in which a lowering of the physical properties of
recycled thermoplastics is of little problem. Therefore, little
care is taken of sorting of thermoplastics contained in electronic
apparatuses, such as copying machines, facsimile machines, personal
computers and their peripheral devices (printers, keyboards, and
displays), and in expendables (e.g., toner cartridges and ink
cartridges) of these electronic apparatuses. As a consequence,
thermoplastics to be recycled contain various contaminants, so it
is impossible to obtain thermoplastics which can be reused as the
same products or parts.
[0004] Also, even when electronic apparatuses and their components
(to be collectively referred to as electronic apparatuses
hereinafter) are manufactured using recycled thermoplastics, these
thermoplastics are in most cases used as packaging containers and
packing materials. That is, recycled plastic materials are not used
to manufacture the original electronic apparatuses. In particular,
labels, seals, and decals (to be collectively referred to as labels
hereinafter) on which explanation of operation of an electronic
apparatus is printed are pasted on external parts of electronic
apparatuses. The base material or adhesive of such a label pasted
on an external part cannot be removed only by cleaning. At present,
the adhesive sticking to the part must be cut away using a cutter
or the like, and this increases the recycling cost.
[0005] Analogously, an electronic apparatus incorporating an ink
holding member for holding ink, represented by an inkjet apparatus
for printing desired character information and image information
(to be collectively referred to as image information hereinafter)
by discharging ink droplets from discharge orifices onto an
arbitrary printing medium, such as paper, cloth, plastic, or metal,
or a cartridge containing ink, has a part to which ink and its
components have stuck. When this part is directly recycled, the
residual ink and its components deteriorate the physical properties
and change the hue of the part. This makes recycling of such parts
very difficult. Furthermore, these inkjet apparatuses contain not
only inks but also pollutants such as a lubricating agent (e.g.,
grease) for mechanical driving portions. Hence, these inkjet
apparatuses require a more complicated process and a higher
recycling cost than those of plastic material recycling that can be
commonly thought of. For this reason, no recycling using components
of inkjet apparatuses as materials have been performed.
[0006] As methods of recycling in this field, some techniques have
been disclosed in Japanese Patent Laid-Open Nos. 5-301222 and
7-323560 and U.S. Pat. No. 2,513,106. The technique disclosed in
Japanese Patent Laid-Open No. 7-323560 has disclosed only a method
of directly reusing parts to be recycled by cleaning.
[0007] The technique disclosed in Japanese Patent Laid-Open No.
5-301222 compensates for a lowering of the physical property values
of recycled plastic materials by additives. The technique disclosed
in U.S. Pat. No. 2,513,106 compensates for a lowering of the
physical property values of recycled plastic materials by polymer
selection.
[0008] On the other hand, a so-called laser engraving technique is
known as a method of displaying desired image information by
changing the color of the surface of a plastic part. This technique
can print operation instructions of an apparatus directly on a
part, so the cost and the number of steps necessary to remove a
pasted label can be reduced. Details of this laser engraving
technique are described in Japanese Patent Publication Nos.
61-11711 and 62-59663. However, these patent publications have
disclosed only the basic techniques of laser engraving and do not
exhibit any practical method pertaining to recycling of
laser-engraved plastics.
[0009] When the physical properties of a material are taken into
consideration, the range of use of a recycled material greatly
widens if physical property values equivalent to those of its
original virgin material are guaranteed. To guarantee physical
property values, however, if the addition of additives or the
selection of polymers is performed in the recycling process as in
the aforementioned prior art, the cost of control of input amounts
of additives or the cost of selection of polymers increases the
total cost of recycling. This can postpone switching from virgin
materials to recycled materials.
[0010] Also, as one characteristic of thermoplastics, linear
patterns such as black streaks or silver streaks sometimes form on
the surface of a molded product owing to the influence of heat
applied during molding. These patterns are primarily caused by the
molding conditions. However, if foreign matter is mixed in a
material itself, a black dot often appears on the surface.
[0011] When laser engraving which discolors or carbonizes the
surface of an object to be processed is performed, the engraved
portion itself can become foreign matter if the object is
thermoplastic. Not only in laser engraving but also during use,
collection, and disassembly of products, rubbish, dust, and foreign
matter adhere to the surfaces of parts to be recycled. If these
parts are not sufficiently cleaned and foreign matter is not well
removed, larger amounts of foreign matter than when virgin
materials are used are produced when these parts are used as
recycled materials. This can impair the product value of especially
external parts of electronic apparatuses.
SUMMARY OF THE INVENTION
[0012] The present invention, therefore, has been made in
consideration of the above situation, and has as its object to
provide a high-quality recycled plastic material of thermoplastic
whose physical property values lower little from those of a virgin
material, without adding any step to commonly performed recycling
steps of pulverizing, cleaning, removable of a cleaner, drying, and
removal of metals and foreign matter and, more particularly, to
provide a recycled plastic material made from thermoplastic used in
an inkjet apparatus including ink and ink components.
[0013] It is another object of the present invention to provide an
electronic apparatus using the above recycled plastic material.
[0014] It is still another object of the present invention to
provide a method of manufacturing a plastic part using the recycled
plastic material.
[0015] It is still another object of the present invention to
provide a method of manufacturing the recycled plastic
material.
[0016] It is still another object of the present invention to
provide a method of reusing a plastic material.
[0017] To solve the above problems and achieve the objects, the
present invention is constituted as follows.
[0018] The first mode of the present invention is a recycled
plastic material made from laser-engraved thermoplastic.
[0019] The second mode of the present invention is a recycled
plastic material manufactured by pulverizing laser-engraved
thermoplastic, cleaning the pulverized thermoplastic, removing a
cleaning solution from the cleaned thermoplastic to dry the
thermoplastic, and removing from the dried thermoplastic solid
matter other than the thermoplastic.
[0020] In the first and second modes of the present invention, the
recycling process of the recycled plastic material does not require
any label peeling step. Also, since no paint such as used in silk
screen printing sticks to the material, the recycling process can
be simplified, and deterioration of the hue of the obtained
recycled plastic material can be prevented.
[0021] The third mode of the present invention is a recycled
plastic material made from thermoplastic containing a metal.
[0022] The fourth mode of the present invention is a recycled
plastic material manufactured by pulverizing thermoplastic
containing a metal, cleaning the pulverized thermoplastic, removing
a cleaning solution from the cleaned thermoplastic to dry the
thermoplastic, and removing from the dried thermoplastic solid
matter other than the thermoplastic.
[0023] In the present invention, not only metals (including metal
particles) contained in thermoplastic as a raw material but also
most metal pieces which can be mixed when the raw material is
pulverized during the recycling process can be easily removed. This
enhances the effect of finally removing solid matter other than the
thermoplastic. Therefore, contamination is very little, so recycled
plastic having high external appearance quality can be
obtained.
[0024] The fifth mode of the present invention is a recycled
plastic material made from thermoplastic used in an inkjet
apparatus.
[0025] The sixth mode of the present invention is a recycled
plastic material manufactured by pulverizing thermoplastic used in
an inkjet apparatus, cleaning the pulverized thermoplastic,
removing a cleaning solution from the cleaned thermoplastic to dry
the thermoplastic, and removing from the dried thermoplastic solid
matter other than the thermoplastic.
[0026] The seventh mode of the present invention is a recycled
plastic material made from thermoplastic to which ink and
components thereof are sticking.
[0027] The eighth mode of the present invention is a recycled
plastic material manufactured by pulverizing thermoplastic to which
ink and components thereof have stuck, cleaning the pulverized
thermoplastic, removing a cleaning solution from the cleaned
thermoplastic to dry the thermoplastic, and removing from the dried
thermoplastic solid matter other than the thermoplastic.
[0028] When a product, such as an ink cartridge, which contains ink
and an ink holding member impregnated with the ink is to be
recycled, an external member of the product must be separated from
the ink holding member. If this external member is cut by a cutter
or the like, a portion of the ink holding member, such as foamed
polyurethane, is often welded to the cut surface. This welded
foamed polyurethane cannot be washed away by cleaning operation
alone. Processes such as cleaning solution removal and drying allow
easy separation of the foamed urethane from the external member.
The state of adhesion of rubbish, dust, and foreign matter to the
product to be recycled cannot be specified. Hence, by executing the
processing following the aforementioned procedure, effective
foreign matter removal is performed with a minimum necessary
load.
[0029] The ninth mode of the present invention is an electronic
apparatus comprising the recycled plastic material according to any
one of the first to eighth modes described above.
[0030] When the recycled plastic material of the present invention
is used in electronic apparatuses rapidly increasing in product
shipment quantity recently, the use and spread of this recycled
plastic material are promoted.
[0031] The 10th mode of the present invention is a method of
manufacturing a plastic part, comprising the steps of disassembling
an electronic apparatus having a laser-engraved thermoplastic part,
separating the thermoplastic part from the disassembled electronic
apparatus and pulverizing the thermoplastic part, cleaning the
pulverized thermoplastic, removing a cleaning solution from the
cleaned thermoplastic to dry the thermoplastic, removing from the
dried thermoplastic solid matter other than the thermoplastic, and
molding a thermoplastic part of the electronic apparatus by using
the thermoplastic, from which the solid matter is removed, as a raw
material.
[0032] The 11th mode of the present invention is a method of
manufacturing a plastic part, comprising the steps of disassembling
an ink container used in an inkjet apparatus, separating a
thermoplastic part from the disassembled ink container and
pulverizing the thermoplastic part, cleaning the pulverized
thermoplastic, removing a cleaning solution from the cleaned
thermoplastic to dry the thermoplastic, removing from the dried
thermoplastic solid matter other than the thermoplastic, and
molding a thermoplastic part of the inkjet apparatus by using the
thermoplastic, from which the solid matter is removed, as a raw
material.
[0033] The 12th mode of the present invention is a recycled plastic
material manufactured by recycling a part molded from a
thermoplastic material, characterized in that an impact strength of
the recycled plastic material is 80% or more of a virgin plastic
material, and a melt flow rate (MFR), indicating the flowability of
a plastic material, of the recycled plastic material is 90 to 120%
of the virgin plastic material.
[0034] The 13th mode of the present invention is a method of
manufacturing a recycled plastic material, characterized in that in
order to recycle a part molded from a thermoplastic material,
plastic is repelletized through steps of pulverization, cleaning,
drying, and foreign matter removal of the molded part, and an
impact strength and a melt flow rate (MFR) of the plastic pellets
are adjusted within the ranges of predetermined values.
[0035] The 14th mode of the present invention is a method of
reusing a plastic material, characterized in that a part is molded
from a plastic material, the molded part is used as a part after a
laser engraving display is formed on the molded part, a recycled
plastic material is formed through steps of pulverization,
cleaning, drying, and foreign matter removal of the part, and an
impact strength of the recycled plastic material falls within a
predetermined range of an impact strength of a virgin plastic
material.
[0036] The 15th mode of the present invention is a method of
reusing a plastic material, characterized in that a plastic
material is molded into an ink container and used as a part, a
recycled plastic material is formed through steps of pulverization,
cleaning, drying, and foreign matter removal of the part, and
physical property values of the recycled plastic material fall
within predetermined ranges of physical property values of a virgin
plastic material.
[0037] The 16th mode of the present invention is a method of
manufacturing a recycled plastic material, characterized in that a
recycling raw material is obtained by successively performing, in
the order named, the pulverizing step of pulverizing a part molded
from a thermoplastic material by using a mesh screen of 4 to 10 mm,
the cleaning step of cleaning a pulverized material obtained in the
pulverizing step by using 10 parts by weight of water as a cleaning
solution with respect to 1 part by weight of the pulverized
material, the dehydrating step of dehydrating the pulverized
material cleaned in the cleaning step by centrifugal. dehydration
to set a moisture content to not more than 0.30 wt %, the foamed
body removing step of removing, by air classification, a foamed
body having a bulk density difference of not less than 0.5 from the
pulverized material dehydrated in the dehydrating step, the first
metal removing step of removing a metal from the pulverized
material by using a magnet having a residual magnetic flux density
of not less than 1 tesla, and the second metal removing step of
removing a metal by using a metal detecting/removing device, and
recycled plastic pellets are obtained by successively performing,
in the order named, the mixing step of sufficiently mixing the
recycling raw material the recycling step of melting, kneading, and
recycling the recycling raw material by an extruder, and the
pelletizing step of pelletizing the material recycled in the
recycling step.
[0038] Other objects and advantages besides those discussed above
shall be apparent to those skilled in the art from the description
of a preferred embodiment of the invention which follows. In the
description, reference is made to accompanying drawings, which form
a part thereof, and which illustrate an example of the invention.
Such example, however, is not exhaustive of the various embodiments
of the invention, and therefore reference is made to the claims
which follow the description for determining the scope of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a perspective view showing the external appearance
of an inkjet printer as an object of the present invention;
[0040] FIG. 2 is a perspective view showing the state in which an
operation cover of the inkjet printer shown in FIG. 1 is
opened;
[0041] FIG. 3 is an enlarged front view of the operation cover
shown in FIG. 2;
[0042] FIG. 4 is a view showing the concept of an example of a
recycled plastic material manufacturing system according to the
present invention;
[0043] FIG. 5 is a sectional view showing the structure of a
cleaning tank incorporated into the manufacturing system shown in
FIG. 4;
[0044] FIG. 6 is a perspective view showing the external appearance
of another inkjet printer as an object of the present
invention;
[0045] FIG. 7 is an enlarged front view of an operation cover of
the inkjet printer shown in FIG. 6;
[0046] FIG. 8 is a perspective view showing the external appearance
of an example of a cartridge used in the inkjet printer;
[0047] FIG. 9 is an exploded perspective view of the cartridge
shown in FIG. 8;
[0048] FIG. 10 is a view showing, together with FIG. 11, the
concept of the work of recycling the cartridge shown in FIG. 8, in
which the state wherein a printed circuit board and a cover plate
are detached is depicted;
[0049] FIG. 11 is a view showing, together with FIG. 10, the
concept of the work of recycling the cartridge shown in FIG. 8, in
which the state wherein an ink tank is cut to remove an ink holding
member is depicted;
[0050] FIG. 12 is a view showing the concept of the work of
conducting a breaking strength test on the cover plate shown in
FIGS. 8 and 9 by using a push-pull gauge;
[0051] FIG. 13 is a view showing the physical property values of
plastic materials of the Example 1 and comparative examples;
[0052] FIG. 14 is a view showing Example 2 and its comparative
examples, and the physical property values of plastic materials of
Example 3;
[0053] FIG. 15 is a view showing the physical property values of
plastic materials of the Examples 2 and 3;
[0054] FIG. 16 is a view showing the physical property values of
plastic materials of the Example 4 and comparative examples;
and
[0055] FIG. 17 is a view showing the physical property values of
plastic materials of the Example 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0056] In the recycled plastic material according to the first or
second mode of the present invention, it is preferable that the
area of laser engraving be 2% or less of the surface area of a
plastic part to be recycled, the width of one scanning line of
laser engraving be 0.15 mm or less, or the depth of laser engraving
be 0.05 mm or less.
[0057] This restricts the discolored matter and carbonization
amount of thermoplastic by a laser and enhances the cleaning effect
during recycling, thereby minimizing the production of foreign
matter on the surface of a molded product. Also, since the amount
of foreign matter is small, a lowering of the physical property
values is suppressed, so the quality of the recycled plastic
material can be held substantially the same as the virgin
material.
[0058] In the recycled plastic material according to the fourth
mode of the present invention, pulverized thermoplastic can also be
separated from metals before being cleaned.
[0059] Also, the step of removing solid matter other than
thermoplastic can have at least one of gravity separation which
uses the true density difference between the thermoplastic and the
foreign matter, magnetic separation which uses magnetic force, and
metal separation which uses an eddy current. Metal separation using
an eddy current is employed for metals, except for ferroelectric
substances, which cannot be separated by magnetic force.
[0060] In the recycled plastic material according to the fourth,
sixth, or eighth mode of the present invention, thermoplastic can
be pulverized by a high-speed pulverizer by using a mesh screen
within the range of 4 to 10 mm, and fine plastic particles of 2 mm
or less, metal particles, and dust particles can be removed using a
shaking screen.
[0061] If the mesh screen for pulverization is less tan 4 mm, the
amount of fine particles increases to increase losses during
cleaning and drying steps, thereby decreasing the yield. In
contrast, if the mesh screen is larger than 10 mm, the size of a
pulverized product becomes too large. This readily causes clogging
and the like in the subsequent processing and lowers the
workability.
[0062] Consequently, most of metals which cannot be removed by
selection before pulverization and metal pieces mixed during
pulverization can be removed. This enhances the effect of removing
final solid matter other than thermoplastic. So, recycled plastic
having very little contamination and having excellent external
appearance quality can be obtained.
[0063] In the recycled plastic material according to the sixth mode
of the present invention, ink and its components, paper dust, and
dust particles sticking to thermoplastic can be removed by cleaning
this thermoplastic. Also, pulverized thermoplastic can be separated
from foreign matter before being cleaned. Furthermore, a cleaning
solution used in cleaning can be filtered through a filter having a
mesh within the range of 25 to 200 .mu.m to reuse the filtered
cleaning solution.
[0064] Most preferably, a cleaning solution used in cleaning is
directly reused. However, a cleaning solution used in cleaning is
colored by coloring agents contained in ink, so it is basically
difficult to directly reuse this cleaning solution owing to
suspended fine particles and the problem of color. In particular,
particulate contamination has adverse effect on the physical
properties of a recycled plastic material and therefore must be
removed. The smaller the mesh size (filtering accuracy) of the
filter used, the more the physical properties of the recycled
plastic material improve, but the more easily filter clogging takes
place. The use of a filter having a mesh within the range of 25 to
200 .mu.m can improve the physical properties of a recycled plastic
material obtained and solve the problem of filter clogging at the
same time.
[0065] A cleaning solution can contain at least one of an additive
for adjusting the pH concentration and a surfactant.
[0066] The pH concentration of ink must be measured from the ink
itself. For example, even if a dye contained in ink is acidic, the
ink itself is alkaline in some cases.
[0067] For instance, when the ink is acidic, a cleaning solution
dissolved in the ink also becomes acidic, and this cleaning
solution becomes an environmental load because its acidic
concentration rises during the process of reuse. Additionally,
cleaning using only water is unsatisfactory depending on the type
of ink, so a large amount of water must be used for long time
periods in order to enhance the cleaning effect. By the addition of
an additive for adjusting the pH concentration and a surfactant,
these inconveniences are solved, and the cleaning process is
completed within a short time.
[0068] Similarly, when the ink is alkaline, the alkali
concentration of a cleaning solution rises during the process of
reuse, and this cleaning solution becomes an environmental
load.
[0069] When the ink is neutral, a cleaning solution is filtered to
remove foreign matter, and the resultant cleaning solution is
directly reused.
[0070] Tap water (pH.apprxeq.7.6, weakly alkaline) can also be used
as a cleaning solution. It is also effective to consider the pH
concentration of this cleaning solution on the basis of tap water.
In the recycled plastic material according to the seventh or eighth
mode of the present invention, ink and its components can be an ink
used in an inkjet apparatus.
[0071] In the recycled plastic material according to the eighth
mode of the present invention, a cleaning solution can be water,
and this water used in cleaning can be reused after being filtered.
If this is the case, a filter for filtering the water preferably
has a mesh within the range of 25 to 200 .mu.m.
[0072] Since the cleaning solution is water, the economical
efficiency and the safety of work improve compared to a case in
which an aqueous cleaning containing an organic solvent, a
surfactant, a builder, and the like is used. In addition, the load
on the environment can be minimized by repetitively reusing the
cleaning solution.
[0073] In the recycled plastic material according to the sixth or
eighth mode of the present invention, the step of removing solid
matter other than thermoplastic can include at least one of gravity
separation using the true density difference between the
thermoplastic and the solid matter, air classification using the
bulk density difference between the thermoplastic and the solid
matter, magnetic separation using magnetic force, and metal
separation using an eddy current. In the air classification, the
bulk density difference between the thermoplastic and the solid
matter to be separated is preferably 0.5 or more.
[0074] The bulk density is the density of pores communicating with
the outside air and internally confined pores in a polycrystalline
substance, powdery layer, or molded product. The true density is
the density of a solid itself, which does not include pores.
[0075] The air classification cannot achieve its effect before the
cleaning step because a bulk density difference is not easily
produced owing to the influence of residual ink, or before the
drying step because a bulk density difference is similarly not
easily produced. To readily produce a bulk density difference, the
air classification step is performed after pulverization, cleaning,
or drying. If the bulk density difference is less than 0.5, not
only the accuracy of precision separation decreases, but also the
yield of the recycling step lowers. Paper dust not completely
removed in the cleaning step can be separated and removed by this
air classification.
[0076] Furthermore, a cleaning solution used in cleaning can be
reused by using a distillation apparatus.
[0077] To reuse a cleaning solution used in cleaning, not only
removal of foreign matter by a filter but also adjustment of the pH
concentration described above are combined into one system. This
improves the cleanness of the cleaning solution when it is reused
and reduce the environmental load.
[0078] The weight ratio of the cleaning solution to the pulverized
thermoplastic can be 10 times or more.
[0079] If the supply ratio of the cleaning solution to the
thermoplastic is less than the above value, the probability of the
thermoplastic parts to be cleaned overlapping each other increases.
This may lower the cleaning effect or make it impossible to
reliably remove the cleaning solution in the subsequent step.
[0080] Inks for printing image information on printing media such
as paper sheets have various compositions for, e.g., writing tools,
stamps, recorders, and inkjet printing. Of these inks, inkjet
printing ink will be explained as an example.
[0081] As representative ink, ink containing a plurality of dyes,
glycerin, urea, IPA (isopropylalcohol), and pure water will be
taken as an example.
[0082] All the dyes are water-soluble, and their balance is
designed by taking account of the clearness upon printing, the
concentration, and the water resistance.
[0083] Glycerin is a high-boiling solvent and has high surface
tension. Hence, glycerin is used to prevent clogging of ink
channels in an inkjet head, particularly clogging at discharge
orifices. Urea is used to further enhance this clogging preventing
effect and further increase the dye concentration of the ink.
Clogging readily occurs especially when the amount of dyes in the
ink increases, and urea has a function of preventing this clogging.
IPA has a function of promoting ink penetration into a printing
medium and moisture evaporation during fixing. This accomplishes
both prevention of deterioration of a recorded image and promotion
of fixation. These components are dissolved in pure water to
prepare inkjet printing ink.
[0084] When ink having the above composition adheres to a plastic
part, moisture evaporates with time, and some of the ink components
such as dyes keep sticking to this plastic part. When the sticking
amount of these ink components is limited to less than 300 ppm, no
visual difference is found between the color of the recycled
plastic material and that of the virgin material.
[0085] If the sticking amount of the ink or the ink components is
large, the hue of the final form is influenced.
[0086] In the recycled plastic material according to the fourth or
eighth mode of the present invention, gravity separation is
preferably performed underwater, and the true density difference
between thermoplastic to be separated and solid matter other than
the thermoplastic is preferably 0.5 or more. Ceramics and metal
oxides having larger true densities than that of thermoplastic are
separated by settling in a cleaning solution such as water. If the
true density difference is less than 0.5, the efficiency of
separation of these substances lowers, and this degrades the yield
of the recycling process.
[0087] Magnetic separation preferably uses a magnet having a
residual magnetic flux density of 1 tesla or more. Thermoplastic
and solid matter other than the thermoplastic are preferably
brought into contact with the magnetic pole of this magnet.
[0088] Magnetic separation is suitable for ferromagnetic metals.
The capture ratio of such ferromagnetic substances lowers if a
magnet having a residual magnetic flux density of less than 1 tesla
is used.
[0089] In the recycled plastic material according to the first to
eighth mode of the present invention, letting I.sub.R and M.sub.R
be the Izod impact value and the melt flow rate, respectively, of
the recycled plastic material, and I.sub.V and M.sub.V be the Izod
impact value and the melt flow rate, respectively, of the virgin
material of thermoplastic before molding, (I.sub.R/I.sub.V)>0.8
and (M.sub.R/M.sub.V)<1.2 are preferably met.
[0090] Of the physical property values of thermoplastic, the Izod
impact value indicates the impact strength of the material and is
used to evaluate characteristics such as impact resistance,
fragility, and toughness. When the material deteriorates and
embrittles, the Izod impact value decreases. The melt flow rate (to
be abbreviated as MFR hereinafter) is a measure indicating the
flowability of thermoplastic in a molten state. The larger the
value, the higher the flowability, and the smaller the molecular
weight of the thermoplastic. When the material deteriorates, its
molecular weight tends to decrease, so the MFR increases.
[0091] The individual physical property values have variations in
virgin materials. Variations of the Izod impact value and the MFR
are said to be about .+-.30%. This is a value at one grade of a
certain material, and for the color of the material a plurality of
colors are taken into consideration. A coloring agent used for
coloration contains pigments, dyes, dispersants, and stabilizers.
The grade and blending ratio of these components change from one
color to another. Therefore, for a color of a certain specific hue,
variations of the Izod impact value and the MFR are small; they can
be thought of as about .+-.25%.
[0092] Also, the physical property values of a recycled plastic
material are highly likely to vary from one lot to another,
depending on the states of collected products as a raw material.
Variations in one lot are expected to be slightly larger than those
of a virgin material.
[0093] Accordingly, in order for a recycled plastic material to
have performance equivalent to that of a virgin material, the
physical property values must be more severely controlled;
variations of the Izod impact value and the MFR are preferably
decreased to .+-.20% or less. As described above, when a material
deteriorates the Izod impact value decreases and the MFR increases.
That is, the Izod impact value and the MFR of a recycled plastic
material must be decreased to -20% or less and +20% or less,
respectively.
[0094] When the Izod impact value and the MFR which significantly
lower during the recycling process fall within the above ranges,
the quality of the recycled plastic material is held substantially
equal to that of the virgin material.
[0095] In addition to the recycled plastic material according to
one of the first to eighth modes of the present invention, the
virgin material of the thermoplastic before molding can also be
used as a raw material.
[0096] Since the basic physical property values are kept in the
range of variations of a virgin material, even when the amount of a
recycled plastic material or the recovery amount of thermoplastic
as a raw material varies, the recycled plastic material can be
stably supplied by changing the mixing ratio.
[0097] In the recycled plastic material according to one of the
first to eighth modes of the present invention, a thermoplastic
material can be an ABS resin (Acrylonitrile Butadiene Styrene
RESIN), a PS resin, or a PS-modified PPE resin (Polyphenylene ether
RESIN modified by Polystyrene).
[0098] ABS and PS resins are so-called styrene-based polymers. An
ABS resin is a copolymer of styrene
(CH.sub.2.dbd.CHC.sub.6H.sub.5), acrylonitrile (CH.sub.3.dbd.CHCN),
and butadiene (CH.sub.3.dbd.CHCH.dbd.C- H.sub.2). A PS resin is a
homopolymer of styrene (CH.sub.2.dbd.CHC.sub.6H.- sub.5). An AS
resin as a copolymer of styrene and acrylonitrile is also a
styrene-based resin.
[0099] A PS resin has relatively low mechanical strength and is
particularly inferior in impact resistance. High-impact polystyrene
(HIPS) is formed by blending an elastic substance such as butadiene
rubber in order to improve this impact resistance. On the other
hand, a PS resin has very high electrical insulating quality and
also has good molding characteristics since it is superior in
thermal stability and flowability in a molten state.
[0100] Acrylonitrile is added to an ABS resin to improve the
chemical resistance and the heat resistance without losing the
characteristics of a PS resin. Butadiene is added to an ABS resin
to improve the impact resistance.
[0101] Since both PS and ABS resins are styrene-based polymers and
they have similar polymer configurations, they are recycled by the
same processing.
[0102] When the present invention is applied to a copolymer of a
different material such as an alloy resin, the recycling conditions
when a virgin alloy resin and a single recycled plastic material
are mixed must be different from the recycling conditions when a
virgin material of single plastic and a single recycled plastic
material are copolymerized. Especially when a virgin alloy resin
and a single recycled plastic material are mixed, a material far
from the physical property values of the virgin alloy resin is
sometimes formed. As an example, when a recycled plastic material
of an ABS resin is mixed in virgin alloy resins of a PC and ABS,
the physical property values depend upon the mixing ratio of this
recycled plastic material of the ABS resin. More particularly, in
mixing an ABS resin in the PC and ABS alloy resin in a stable
polymer alloy state, an excessive amount of the ABS resin to be
mixed indicates that incompatible matter with the PC and ABS alloy
resin is mixed to influence the physical properties. When a
recycled plastic material is used as a raw material for an alloy
resin, an alloy resin must be prepared using a control value
different from that for the virgin material.
[0103] An ABS virgin resin is used for the same ABS material. In
this manner, the use of the same recycled plastic material obviates
the need to control fine variations of the physical property values
during polymerization and thereby simplifies the control of the
physical property values of the recycled plastic material.
[0104] A cleaning solution is preferably removed from cleaned
thermoplastic by the centrifugal removing method, and the moisture
content of the final recycled plastic is preferably 0.30 wt % or
less. If the moisture content is 0.30 wt % or more, the possibility
of the flaky thermoplastic parts sticking to each other increases,
and this produces adverse effect on thermoplastic which readily
hydrolyzes. Also, the cleaning solution removal time is shortened
compared to a filtering method using a filter, and this prevents
deterioration of the color of the final recycled plastic
material.
[0105] In the electronic apparatus according to the ninth mode of
the present invention, a recycled plastic material can also include
external parts of the electronic apparatus.
[0106] Since the present invention is applicable to external parts
whose workmanship is severely evaluated, the physical property
values of the materials can be maintained. In addition, the product
value of the external appearance does not degrade even when the
recycled plastic material is used. This greatly widens the range of
applications of the recycled material. Also, the basis of material
recycling is ideally recycling to a product or a part as a raw
material. Therefore, recycling to an inkjet apparatus (including
its parts) is desirable in this respect.
[0107] In the method of manufacturing a plastic part according to
the 10th mode of the present invention, an electronic apparatus can
be an inkjet apparatus, and thermoplastic parts can be external
members of this inkjet apparatus.
[0108] In the method of manufacturing a plastic part according to
the 11th mode of the present invention, a molded thermoplastic part
can be a cover plate of an ink container.
[0109] [Embodiments]
[0110] Embodiments in which a recycled plastic material and an
electronic apparatus according to the present invention are applied
to an inkjet printer will be described in detail below with
reference to FIGS. 1 to 17. However, the present invention is not
limited to these embodiments and is similarly applicable to other
techniques to be included in the concept of the present invention
described in the scope of claims of this specification.
[0111] An inkjet printer as an object of the present invention
prints by discharging ink from a printing head onto a printing
medium. This inkjet printer has the advantages that the printing
means can be made compact, high-definition images can be printed at
high speed, images can be printed on plain paper sheets without any
specific processing, the running cost is low, noise is little
because the printer is of non-impact type, and color images can be
readily printed by using inks of multiple colors.
[0112] The external appearance of this inkjet printer is shown in
FIG. 1. That is, an inkjet printer 11 of this embodiment includes
an openable operation cover 14 between an upper case 12 and a lower
case 13. As shown in FIG. 2, the operation cover 14 can be held
open. On the inner surface of this operation cover 14, as shown in
FIG. 3 which is an enlarged view of this portion, an illustration
15 depicting operation instructions of this inkjet printer 11 is
laser-engraved. The operation cover 14 including this
laser-engraved portion is used as the raw material of a recycled
plastic material of this embodiment.
[0113] FIG. 4 shows an outline of the configuration of a recycling
system of this embodiment. That is, a pulverizer 101 pulverizes the
raw material of a recycled plastic material into a predetermined
size. A conveyor apparatus 102 conveys the pulverized raw material
in units of predetermined amounts to a shaking screen 103. Fine
particles which cause clogging or the like in the later work are
discharged to a waste tank 104. The raw material which is not
sufficiently pulverized is collected in a collecting tank 105 and
returned to the pulverizer 101. The raw material which is
pulverized into the predetermined size is passed through a magnetic
separator 106 to capture ferromagnetic metals contained in the raw
material. The resultant raw material is supplied to a hopper 108 of
a screw feeder 107. This screw feeder 107 is driven by a motor 109
to supply the raw material in units of predetermined amounts into a
cleaning solution tank 110.
[0114] FIG. 5 shows an outline of the structure of the cleaning
solution tank 110 of this embodiment. That is, the cleaning
solution tank 110 of this embodiment is partitioned into a
plurality of baths to separate plastic as a recycling raw material
by using the specific gravity difference between this plastic and
foreign matter such as metals. The raw material flowing into the
final bath is dehydrated by a cleaning/dehydrating apparatus 113,
which is driven by a motor 112, and supplied to a cyclone 115 by an
air blower 114.
[0115] A cleaning solution W overflowing from an overflow weir 116
of the cleaning solution tank 110 is supplied from a buffer tank
117 to a distillation concentrator 118. This distillation
concentrator 118 supplies a purified cleaning solution to a
condensate tank 119, and the cleaning solution is returned to the
cleaning solution tank 110. The distillation concentrator 118 also
discharges the residual solution colored by concentrated ink or the
like to a concentrated solution tank 120.
[0116] A portion of the cleaning solution W overflowing from the
overflow weir 116 is supplied little by little into the screw
feeder 107 through a filter 121. The supplied cleaning solution is
used as a lubricating agent to move the raw material in this screw
feeder 107.
[0117] The raw material supplied to the cyclone 115 described above
is air-classified in this cyclone 115 and dropped in units of
predetermined amounts into an aspirator 123 by a rotary valve 122.
A foamed polyurethane resin (which is contained in a cartridge to
be described later and functions as an ink holding member) having a
smaller bulk specific gravity than that of the raw material of a
recycled plastic material is discharged to a collecting tank 125 by
a blower 124.
[0118] The raw material flowing down from the aspirator 123 with
metal particles and the like sticking to it is again passed through
a magnetic separator 126 to capture and separate ferromagnetic
metal particles sticking to its surface. The resultant raw material
is supplied to a stock tank 129 of a screw feeder 128 by an air
blower 127. The screw feeder 128 supplies this raw material in
units of predetermined amounts to a metal separator 131 for
separating metals from the raw material by using an eddy current or
the like. This metal separator 131 separates metal particles
contained in the raw material and discharges the metal particles to
a collecting tank 132.
[0119] The raw material separated by the metal separator 131 is
supplied into a hopper 134 by a blower 133 and collected as a final
recycled plastic material by a collecting vessel 135.
EXAMPLE 1
[0120] About 40 kg of a raw material were manufactured by
laser-engraving an illustration 20 of operation instructions as
shown in FIG. 7 on an operation cover 19 (material: ABS resin,
average thickness 2.5 mm, true density 1.05) of an inkjet printer
(BJC-430J: manufactured by CANNON INC.) as shown in FIG. 6. This
ABS resin does not contain any filler or reinforcer for imparting
characteristics such as strength, slidability, and flame
retardency. A different material such as a nameplate is not adhered
to the ABS resin, either.
[0121] A laser engraving machine used in this embodiment is
SMU65DT10DK (manufactured by BAASEL LASERTECH, Germany). It has a
Nd:YAG laser as a laser source, a wavelength of 1.064.mu.m, an
output of 65 W, a turntable diameter of 1,000 mm, and a lens focal
length of 254 mm. This laser engraving machine also includes two
engraving heads whose maximum engraving region diameter is 230 mm.
It also includes an exhaust pump with filter in order to remove
fume generated during laser engraving.
[0122] The nozzle of this exhaust pump is set as close as possible
to the laser irradiation position so that the generated fume does
not again adhere to the engraved surface of the operation cover 19
to degrade the quality of the engraved portion.
[0123] The line width of one scanning of a laser is an element
determined from visibility. For example, the line width need only
be 0.3 mm when characters laser-engraved on a white plastic
material are to be viewed from a position 30 cm away. However, when
the engraving contents such as operation instructions of
particularly an electronic apparatus contain the illustration 20 as
shown in FIG. 7, if an image portion in which repetitive scanning
lines are densely formed and a character portion are engraved under
the same conditions, the image portion is deeply engraved.
Additionally, the protuberance of the resin around the engraved
portion increases in size to break the contour. This consequently
lowers the visibility. Accordingly, it is necessary to keep the
balance of molten portions by engraving a plurality of times at the
same depth while gradually shifting the position.
[0124] If the line width is large, the energy of laser increases
the amount of discolored matter or carbide which can be foreign
matter with respect to a recycled plastic material. Therefore, a
system based on the balance between the amount of discolored matter
or carbide and the visibility must be considered.
[0125] On the other hand, the deeper the engraved portion, the
higher the contrast between this engraved portion and the surface,
so the visibility improves. However, during recycling a deeper
engraved portion is more difficult to clean. This increases the
possibility of foreign matter remaining. To sufficiently supply a
cleaning solution to an engraved portion, the section of a scanning
line is preferably set to be semicircular. That is, the ratio of
the engraving depth to the line width is preferably held 1/2 or
less.
[0126] In many laser engraving machines, the scanning rate of an
engraving head is variable. The line width and depth of engraving
can be adjusted to optimum values by the energy amount of laser and
the scanning rate of the engraving head. Consequently, the
visibility of engraving of an image portion and that of a character
portion can be held equivalent to each other.
[0127] The scanning rate depends upon the energy amount of a laser
engraving machine used. However, the present inventors examined by
taking the above elements into consideration and have found that to
ensure visibility and prevent the production of discolored matter
or carbide, it is preferable to set the line width and depth of one
scanning of laser to 0.2 mm or less and 0.1 mm or less,
respectively.
[0128] Compatibility with a different material is evaluated as
follows. For example, a certain substance B is mixed at a weight
ratio of C % in a substance A as a reference to measure physical
property values. If the physical property values are equivalent to
those of the substance A, the substance B is evaluated to have
compatibility with the substance A. In the evaluation of
compatibility label placed on the market, C=1% is generally
used.
[0129] Since engraving by a laser is superficial, the weight ratio
described above must be replaced with the surface area ratio by
taking account of the thickness of a material to be engraved.
[0130] Of thermoplastics, those said to be suited to recycling do
not contain any reinforcers or fillers. In the case of an ABS
resin, PS resin, and PS-modified PPE resin, the thickness of a
product is preferably 3.0 mm or less, except for special molding
such as gas-assisted molding, when the transfer properties from a
metal mold during injection molding are taken into consideration.
Also, when the load resistance (strength) as a product of an
electric/electronic apparatus is taken into account, the thickness
must be approximately 2.0 mm or more if there is no reinforcement
by other members.
[0131] Accordingly, the area of laser engraving is preferably t %
or less of the surface area in accordance with a thickness t mm of
a plastic part to be engraved, and is preferably 3.0% or less in
electric/electronic apparatuses.
[0132] Alternatively, the line width of one scanning of laser
engraving is set to 0.2 mm or less, or the depth of laser engraving
is set to 0.1 mm or less. This is desirable to use this plastic
part as a recycled plastic material.
[0133] When the thickness of product, the energy amount of laser,
the visibility including a protuberance around the engraved
portion, and the productivity (the tact time required for laser
engraving, i.e., the irradiation time) are taken into
consideration, laser engraving is optimally done if the laser
engraving area is 3% or less of the surface area, the line width of
one scanning is 0.15 mm or less, and the engraving depth is 0.05 mm
or less.
[0134] In this embodiment, the thickness on the irradiated surface
of one line engraved by the emitted laser was 0.12 mm, the depth
from the irradiated surface was 0.05 mm, and the engraved area was
about 920 mm. The surface area of the operation cover 19 described
above was 686 cm, and the area ratio occupied by the laser engraved
portion was 1.34%. The protuberance of a carbide formed by heat of
the laser was not included in the measurements of the thickness and
depth of the line.
[0135] To further improve the visibility of the engraved portion,
processing data used in the laser engraving of this embodiment is
obtained by partially changing a printing plate commonly used for
an operation cover. For example, in a portion where two lines
overlap, one line is cut to keep the balance of a portion melted by
a laser uniform as a whole.
[0136] This operation cover was pulverized by attaching a 6-mm mesh
screen to the pulverizer 101 (JC-10: manufactured by Morita Seiki
K.K.) shown in FIG. 4.
[0137] The pulverized product was cleaned and the cleaning solution
was removed by using a cleaning.cndot.cleaning solution removing
apparatus (HIGHCHIP CLEANER CFP-500: manufactured by Toyo Seiki
K.K., corresponding to 110 and 113 in FIG. 4). The plastic charge
rate was 2.5 kg/min., and the flow rate of the cleaning solution W
(tap water) was 80 liters/min. This cleaning solution W was
received by the cleaning solution tank 110 having a capacity of
2,000 liters as shown in FIG. 5. To circulate and reuse the
cleaning solution W by using a pump (not shown), the cleaning
solution W was filtered by a filter housing (EBF112S6M:
manufactured by Loffler K.K.) containing a nylon monofilament
(R100NMO12M bug filter: manufactured by Loffler K.K., filtering
accuracy 100 .mu.m)
[0138] The cleaned pulverized product from which the cleaning
solution was removed was supplied to an air-classification
aspirator system (KF-12: manufactured by Horai K.K., corresponding
to 123 in FIG. 4) by the air blower 114 (DF-5: manufactured by
Horai K.K.) and classified into low-bulk-density foreign matter and
the other pulverized product.
[0139] The pulverized product passed through the air-classification
aspirator system was dropped onto the magnetic separator 126 (MAGIC
CATCH: manufactured by JMI K.K., residual magnetic flux density 1.3
tesla) to separate ferromagnetic components.
[0140] Subsequently, the pulverized product was conveyed to the
stock tank 129 by the air blower 127 (DF-1: manufactured by Horai
K.K.) This pulverized product was conveyed at a ratio of about 3
kg/min. from the stock tank 129 to an eddy current type metal
detecting/removing apparatus (MDS-30A: manufactured by Sensor
Technology K. K., corresponding to 131 in FIG. 4), thereby removing
metal components. The finally obtained cleaned pulverized material
weighed 38 kg.
[0141] The amount of moisture sticking to the obtained cleaned
pulverized material was measured by the gravimetric method and
found to be 0.11 wt %. Also, residual metal components were
visually zero.
[0142] This cleaned pulverized material was pelletized. The
obtained pellets were used to form five sample pieces (based on
ASTM-D256: with 1/4-inch notch) for Izod impact testing, and the
Izod impact strength was measured.
[0143] The pelletization process was performed by attaching a
60-mesh filter to an extruder (DMG-40: manufactured by Nippon
Purakon) and melting, kneading, and extruding the material at a
cylinder temperature of 210.degree. C. Izod impact testing sample
pieces were formed using the pelletized pulverized material
described above by setting an ASTM testing sample piece family mold
in an injection molding machine (IS-80G: manufactured by Toshiba
Machine Co., Ltd.) and injection-molding the material at a cylinder
temperature of 200.degree. C.
[0144] Color difference measurement (based on JIS-Z8722 condition
D) was performed using Izod impact testing sample pieces formed
from virgin pellets as a color difference standard with respect to
the above sample pieces. Analogously, the MFR (based on JIS-K7210:
220.degree. C., load 98.07N) was measured five times. The results
are indicated by S.sub.1 in FIG. 13.
[0145] A color difference .DELTA.Eab* in FIG. 13 is calculated as
per JIS-K7105 by:
.DELTA.Eab*=[(.DELTA.L*)+(.DELTA.a*)+(.DELTA.b*)]
[0146] The MFR (Melt Flow Rate) described above was measured in
accordance with JIS-K7210B. This method measures the extrusion rate
when molten thermoplastic is extruded at a prescribed temperature
and pressure through a die (a metal block with a shaping
mouthpiece) having a prescribed length and diameter. The method B
is an automatic time measurement method applied to a material whose
MFR is 0.50 to 300 g per 10 min.
[0147] A Techno Seven Full-Automatic Melt Indexer (#270) was used
as the testing apparatus. The die (extruding portion) had a length
of 8.0173+0.025 mm and an inside diameter of 2.092+0.002 mm.
[0148] This testing apparatus was filled with 7 g of a sample
(resin) dried at 80.degree. C. for 2 hr at a time. After being
preheated at 220.degree. C. for 6 min., the sample was extruded at
the same testing temperature of 220.degree. C. and a testing load
of 98.07N (10 kgf). A time t (sec.) during which the piston moved
25.0 mm (L) was measured, and the MFR was calculated by: 1 MFR (
220 , 98.07 , B ) = 42.6 .times. L .times. / t = 42.6 .times. 25.0
.times. 0.953 / t
[0149] Note that a melt density .rho. of the resin at the testing
temperature was 0.953 g/cm.sup.3.
[0150] Before the above recycling process was carried out, the
physical property values in virgin pellet state of the material
used were measured. The results are indicated by R.sub.V in FIG.
13. Also, to confirm changes in the physical property values due to
injection molding, the above recycling process was performed using
a comparative sample formed without laser-engraving the operation
cover 19. The results are indicated by R.sub.1 in FIG. 13.
[0151] As shown in FIG. 13, the Izod impact value and the MFR
reduced 6.3% and 2.9%, respectively, from R.sub.V to R.sub.. From
R.sub.V to S.sub.1, the Izod impact value reduced 12.5% (6.7% with
respect to R.sub.1), whereas the MFR increased 0.6% (3.6% with
respect to R.sub.1). To give a recycled plastic material a
performance equivalent to that of a virgin material, the Izod
impact strength R.sub.V must be 0.8 times or less, and the MFR must
be less than 1.2 times. From this viewpoint, the change rates of
the physical property values described above well satisfy the
characteristics of a recycled plastic material.
[0152] The color difference was evaluated by taking account of
color difference variations in the virgin pellet state. In the case
of an ABS resin, variations of color having influence on
particularly .DELTA.b are large, so complement is possible in the
same process as a virgin material if .DELTA.b*.ltoreq.1.0.
Therefore, since .DELTA.Eab*=0.88 is mostly composed of
.DELTA.b*=0.79, the recycled plastic material can be used in the
same manner as the virgin material.
[0153] The residual moisture was also 0.11 wt %, indicating that
adverse effect on plastic caused by hydrolytic properties could be
prevented.
[0154] The inkjet printer 11 (BJF-600: available from CANNON INC.)
shown in FIGS. 1 to 3 is currently produced and sold by forming all
of its plastic parts by using virgin materials. This inkjet printer
11 was manufactured using the cleaned pulverized material obtained
through the above recycling process. More specifically, the cleaned
pulverized material was applied to an upper case 12 (average
thickness 2 mm, weight 389 g), a lower case 13 (average thickness 2
mm, weight 545 g), and an operation cover 14 (average thickness 2.3
mm, weight 159 g). FIG. 3 shows the state in which the illustration
15 for explaining operation was laser-engraved on the operation
cover 14.
[0155] No difference was visually found between the external
appearance and color (hue, saturation, and lightness) of each of
these three parts and a corresponding part manufactured using the
virgin material.
[0156] The external surface area of BJF-600 including this
operation cover 14 is 4,920 cm.sup.2, and the surface area of the
laser-engraved portion is 920 mm.sup.3. The ratio of the area of
the laser-engraved portion to the external surface area is 0.187%.
Compared to the aforementioned experiment, the area ratio of the
laser-engraved portion reduces from 1.34% to 0.187%. In addition, a
tray 21 for holding printed sheets is also formed using the same
plastic material. Also, the operation cover 14 alone need not be
recycled in a separate step in the recycling process. It is
unlikely to recycle only the operation cover 14 in consideration of
the number of steps.
[0157] Accordingly, the physical property values of the recycled
plastic material manufactured using the external parts 12 to 14 of
this inkjet printer 11 are expected to be closer to those of the
virgin material than the physical property values obtained in the
recycling process described above.
COMPARATIVE EXAMPLE OF EXAMPLE 1
[0158] Thermoplastic was recycled following the same procedures as
in the Example 1 except that the contents of laser engraving were
printed on a PS resin label (thickness 150 .mu.m) and this label
was pasted on the operation cover 19. The area of the pasted label
was 186.2 cm.sup.3, and its weight ratio to the operation cover 19
was about 3%.
[0159] The physical property values of this cleaned pulverized
material, measured under the same conditions as virgin pellets,
were that the Izod impact value was 97.1 J/m, the MFR was 53.7 g/10
min., and the color difference .DELTA.E was 1.03. The measured
physical property values are indicated by C.sub.in FIG. 13.
[0160] As shown in FIG. 13, from R.sub.V to C.sub.1, the Izod
impact value decreased 38.1%, and the MFR increased 10.0%. As
described above, to obtain the performance equivalent to the virgin
material, it is necessary to make the Izod impact strength 0.8
times or less and the MFR less than 1.2 times. Therefore, the
recycled plastic material obtained from the operation cover 19 on
which the PS resin label having the illustration formed by
printing, instead of laser engraving, was pasted did not satisfy
the. required characteristics. Also, the color difference was
larger than 1.0, indicating inferior quality to that of the virgin
material.
[0161] In the above Example, external members of an inkjet printer
are used to form a recycled plastic material. A modification in
which the present invention is applied to a cartridge of the
aforementioned inkjet printer will be described below.
[0162] FIG. 8 shows the external appearance of the cartridge as an
object of this modification. FIG. 9 shows the exploded state of the
cartridge. That is, a cartridge 31 of this modification is formed
by integrating an inkjet printing head 32 for discharging ink by
using thermal energy and an ink tank 33. This cartridge 31 is
mounted to be replaceable in an inkjet printer of the above
type.
[0163] The printing head 32 of this cartridge 31 has electrothermal
transducers, formed on a substrate through the semiconductor
fabrication processes such as etching, vapor deposition, and
sputtering, electrodes, liquid channel walls, and a top plate.
[0164] A heater board 34 has a structure in which electrothermal
transducer elements and aluminum lines for supplying power to these
electrothermal transducer elements are formed by the film formation
technology. Reference numeral 35 denotes a printed circuit board
corresponding to the heater board 34, and corresponding lines are
connected by, e.g., wire bonding. A top plate 36 has partitions for
limiting ink flow channels and a common ink compartment. In this
modification, this top plate 36 is formed using thermoplastic
having an integrated discharge port plate.
[0165] Reference numeral 37 denotes a metal base plate; and 38, an
SUS press spring. The base plate 37 and the press spring 38 are
combined with the heater board 34 and the top plate 36 sandwiched
between them. Consequently, the heater board 34 and the top plate
36 are fixed by pressure. The printed circuit board 35 is fixed by
adhesion or the like to the base plate 37. This printed circuit
board 35 also functions as a member for radiating heat, generated
when ink is discharged, from the heater board 34.
[0166] A sub-tank 39 receives ink supplied from the ink tank 33 as
an ink supply source and guides the ink to a common liquid
compartment, formed by junction of the heater board 34 and the top
plate 36, via a supply pipe 40 molded from plastic. An SUS filter
41 is placed in a portion of the sub-tank 39 close to a port for
supplying ink to the common liquid compartment. This SUS filter 41
is attached by a filter fixing member 42 which is a plastic molded
product. Reference numeral 43 denotes a cover plate whose pawl 43a
is welded to a boss 39a formed on the sub-tank 39. This cover plate
43 is a plastic molded product. An ink holding member 44 to be
impregnated with ink is made of a foamed polyurethane resin and
placed in the ink tank 33. A supply port 45 supplies ink to a
discharge unit including the components 34 to 43 described above.
In the step before this discharge unit is placed in the ink tank
33, the ink holding member 44 can be impregnated with ink by
injecting it from the supply port 45. Reference numeral 46 denotes
a cover member of the ink tank 33; and 47, an air communicating
port which allows the interior of the cartridge 35 to communicate
with the air.
[0167] Ink as disclosed in Japanese Patent Publication No. 7-119378
is known as ink contained in the ink tank 33 of this cartridge 31.
Ink containing pigments is also well known as well as ink
containing dyes as coloring agents.
EXAMPLE 2
[0168] 2,000 used cartridges 31 (BC-02: available from CANNON INC.)
shown in FIGS. 8 and 9 were collected. As shown in FIG. 10, a cover
plate 43, a printing head 32, a printed circuit board, and a base
plate 37 were removed from an ink tank 33, and the ink tank 33 was
cut from a cut line L indicated by the alternate long and two short
dashed line. As shown in FIG. 11, an ink holding member 44
accommodated in the ink tank 33 was extracted. Consequently, about
30 kg of external members (material: PS-modified PPE, true density
1.08) of the ink tanks 33 were obtained as a recycling raw
material. All of these plastic parts were manufactured by the same
lot. The physical property values in the virgin pellet state before
use were an Izod impact test value (based on ASTM-D256: sample size
2.5.times.0.5.times.0.25 (inch), with mold notch) of 90.2 J/m, and
an MFR (based on ASTM-D1238: 250.degree. C., load 98.07N) of 44
g/10 min. The measured physical property values are indicated by
R.sub.2 in FIG. 14.
[0169] Note that the color difference was calculated by a color
difference expression based on JIS-K7105 from tristimulus values
obtained in accordance with JIS-Z8722 condition D.
[0170] Of the materials constructing this cartridge 31, materials
other than the external members are stainless steel for a filter 41
for preventing clogging of ink discharge ports, PP, PTFE, and
glass; and various rubber materials and metals as sealing
materials, a foamed urethane resin and a porous molded product as
the ink holding member 44, and ink. Furthermore, materials
constructing the printing head 32 are a glass epoxy substrate, an
aluminum substrate, gold and copper as wiring materials, and super
engineering plastic as a discharge port plate (not shown).
[0171] These used external members were pulverized by attaching an
8-mm mesh screen to the pulverizer 101 (VC-210: manufactured by
Horai K.K.) shown in FIG. 4. Ink and its components adhered in an
amount of 1,200 ppm on the average to this plastic pulverized
product. Also, about 200 ppm of metals such as the SUS filters 41
and steel spheres (true density 7.9) constructing the cartridges
31, which were not completely separated out, and about 400 ppm of
the ink holding members 44 (bulk density 0.041) as cut scraps were
mixed (both were visually separated out and measured by the
gravimetric method).
[0172] This pulverized product was cleaned and the cleaning
solution was removed by using a cleaning.cndot.cleaning solution
removing apparatus (HIGHCHIP CLEANER CFP-500: manufactured by Toyo
Seiki K.K.) The plastic supply rate was 2.5 kg/min., and the flow
rate of the cleaning solution W (in this embodiment, tap water) was
80 liters/min. The weight ratio of the supply amount of the
cleaning solution to the supply amount of the raw material per unit
time was 32/1. The cleaning solution was received by the cleaning
solution tank 110 having a capacity of 2,000 liters as shown in
FIG. 5. Before being pumped up and reused, the cleaning solution
was filtered by a filter housing (EBF112S6M: manufactured by
Loffler K.K.) containing a nylon monofilament (R100NMO12M:
manufactured by Loffler K.K.)
[0173] The cleaned pulverized product from which the cleaning
solution was removed was supplied to an air-classification
aspirator system (KF-12: manufactured by Horai K.K.) by the air
blower 114 (DF-5: manufactured by Horai K.K.) and classified into
the low-bulk-density ink holding members 44 and the other
pulverized product.
[0174] The pulverized product passed through the air-classification
aspirator system was dropped onto the magnetic separator 126 (MAGIC
CATCH: manufactured by JMI K.K., residual magnetic flux density 1.3
tesla) to separate ferromagnetic components.
[0175] Subsequently, the pulverized product was conveyed to the
stock tank 129 by the air blower 127 (DF-1: manufactured by Horai
K.K.). This pulverized product was conveyed at a ratio of about 3
kg/min. from the stock tank 129 to an eddy current type metal
detecting/removing apparatus (MDS-30A: manufactured by Sensor
Technology K.K.), thereby removing metal components. The finally
obtained cleaned pulverized material weighed 28 kg.
[0176] The amounts of moisture and ink sticking to the obtained
cleaned pulverized material were measured by the gravimetric method
and the calorimetric spectroscopy and found to be 0.1 wt % and 90
ppm, respectively. Also, residual metal components and foamed
urethane resin were visually zero. This cleaned pulverized material
alone was used to form five Izod impact testing samples (based on
ASTM-D256: sample size 2.5.times.0.5.times.0.25 (inch), with mold
notch). The average value of the Izod impact strengths measured was
89.2 J/m.
[0177] Color difference measurement was performed using Izod impact
testing sample pieces molded from virgin pellets as a color
difference standard with respect to the above sample pieces. The
.DELTA.E was found to be 0.43. Analogously, the MFR (based on
ASTM-D1238: 250.degree. C., load 98.07N) was measured three times,
and the average value was 42 g/10 min. The measured physical
property values are indicated by S.sub.2 in FIG. 14.
[0178] As shown in FIG. 14, the Izod impact value and the MFR
reduced 1.1% and 4.5%, respectively, from R.sub.2 to S.sub.2. To
give a recycled plastic material a performance equivalent to that
of a virgin material, it is necessary to make the Izod impact
strength 0.8 times or less and the MFR less than 1.2 times. The
change rates of the above physical property values well satisfy the
characteristics of a recycled plastic material.
[0179] The color difference was evaluated by taking account of
color difference variations in the virgin pellet state. In the case
of a PS-modified PPE resin, .DELTA.E .ltoreq.1.0 was a target.
Since .DELTA.E was 0.43, this material can be used in the same
manner as the virgin material.
[0180] The residual moisture was also 0.10 wt %, indicating that
adverse effect on plastic caused by hydrolytic properties could be
prevented. The residual ink amount was 90 ppm. From these results,
the recycled plastic material manufactured by this embodiment is
considered to be usable in the same manner as the virgin
material.
[0181] To further confirm the characteristics, this cleaned
pulverized material alone was used to mold 100 cover plates 43 of
the cartridge 31. Separately, 100 identical comparative samples
were molded from virgin pellets. 10 plates selected at random from
each group were attached to a dedicated jig 201 shown in FIG. 12,
and the breaking strength of a pawl 43a of the cover plate 43 was
measured using a push-pull gauge 202. The results are indicated by
S.sub.2 in FIG. 15.
[0182] The breaking strength of the pawl 43a indicated by S.sub.1
in FIG. 15 increased 3.1%. This demonstrates that both the bending
strength and the toughness were equivalent to those of the virgin
material.
COMPARATIVE EXAMPLE OF EXAMPLE 2
[0183] To confirm the effect of separation of solid matter (to be
also referred to as foreign matter hereinafter) such as metals
other than thermoplastic performed after cleaning, a raw material
was recycled by the same recycling process as in the Example 2
except that neither air classification using the bulk density
difference nor metal separation using eddy current were performed
by turning off the air-classification aspirator system (KF-12:
manufactured by Horai K.K.) and the eddy current type metal
detecting/removing apparatus (MDS-30A: manufactured by Sensor
Technology K.K.)
[0184] The weight of external members of the ink tanks 33 of the
cartridges 31 supplied was about 30 kg, and the weight of a cleaned
pulverized material obtained was 28 kg. The amount of metal
components contained was 100 ppm (measured by the gravimetric
method). The physical property values of this cleaned pulverized
material were an Izod impact test value of 66.6 J/m, an MFR of 56
g/10 min., and a color difference .DELTA.E of 0.60. The measured
physical property values are indicated by C.sub.2 in FIG. 14.
[0185] As shown in FIG. 14, from R.sub.2 to C.sub.2, the Izod
impact value decreased 26.2%, and the MFR increased 27.3%; the Izod
impact value exceeded 0.8 times, and the MFR was 1.2 times or more.
The residual moisture was 0.25 wt %. Although this value is less
than 0.30 wt %, the residual metal amount was as large as 100 ppm.
Consequently, it was possible to confirm the effects of air
classification and metal separation for a recycled plastic material
having a performance equivalent to that of a virgin material.
EXAMPLE 3
[0186] Cleaning, cleaning solution removal, drying, and precision
separation were performed following the same procedures as in the
Example 2 except that a 6-mm mesh screen was used in pulverization
and the plastic supply rate and the cleaning solution flow rate
were set to 8 kg/min. and 80 liters/min., respectively, during
cleaning. As a consequence, the cleaned pulverized material
obtained weighed 27 kg.
[0187] The physical property values of this cleaned pulverized
material were an Izod impact test value of 87.2 J/m, an MFR of 43
g/10 min., and a color difference .DELTA.E of 0.49. These measured
physical property values plus the residual moisture and the like
are indicated by S.sub.3 in FIG. 14.
[0188] As shown in FIG. 14, from R.sub.3 to S.sub.3, the Izod
impact value decreased 3.3%, and the MFR increased 2.2%. As
described previously, to give a recycled plastic material a
performance equivalent to that of a virgin material, it is
necessary to make the Izod impact strength 0.8 times or less and
the MFR less than 1.2 times. The change rates of the above physical
property values well satisfy the characteristics of a recycled
plastic material.
[0189] The color difference .DELTA.E was 0.49, and the residual
moisture was 0.15 wt %; both values were satisfactory to obtain the
performance equivalent to the virgin material. The residual ink
amount was 150 ppm. However, when the other physical property
values and color difference measured are taken into consideration,
the quality of this material is considered to be equivalent to the
virgin material.
[0190] To further confirm the characteristics, this cleaned
pulverized material alone was used to mold 100 cover plates 43 of
the cartridge 31. 10 plates selected at random from these 100
plates were attached to the dedicated jig 201, and the breaking
strength of the pawl 43a of the cover plate 43 was measured using
the push-pull gauge 202. The results are indicated by S.sub.3 in
FIG. 15.
[0191] The breaking strength of the pawl indicated in FIG. 15
increased 1.2%. This demonstrates that both the bending strength
and the toughness were equivalent to those of the virgin
material.
EXAMPLE 4
[0192] 40 used inkjet printers (BJC-430: manufactured by CANNON
INC.) shown in FIG. 6 were collected to obtain about 40 kg of
external members (all made from an ABS resin: true density 1.05)
including front covers 17, rear covers 18, and operation covers 19.
A nameplate adhered to the front surface of each operation cover 19
and rubber legs projecting from the bottom surface of each rear
cover 18 were removed in advance.
[0193] The physical property values in the virgin pellet state of
the ABS resin used were an Izod impact test value (based on
ASTM-D256: with 1/8-inch notch) of 157.8 J/m, and an MFR (based on
JIS-K7210: 220.degree. C., load 98.07N) of 40.7 g/10 min. A maximum
of about 700 ppm of ink and its components adhered to this plastic
pulverized product (the amount of the adhered ink and its
components was measured by the colorimetric spectroscopy). Also,
metals or ink holding members not completely separated were not
found by visual checking. The measured physical property values are
indicated by R.sub.4 in FIG. 16.
[0194] Note that the color difference was calculated by a color
difference expression based on JIS-K7105 from tristimulus values
obtained in accordance with JIS-Z8722 condition D.
[0195] These used external members were pulverized by attaching a
6-mm mesh screen to the pulverizer 101 (JC-10: manufactured by
Morita Seiki K.K.) shown in FIG. 4.
[0196] This pulverized product was cleaned and the cleaning
solution was removed by using a cleaning.cndot.cleaning solution
removing apparatus (HIGHCHIP CLEANER CFP-500: manufactured by Toyo
Seiki K.K.) The plastic supply rate was 2.5 kg/min., and the flow
rate of the cleaning solution W (in this embodiment, tap water) was
80 liters/min. The cleaning solution was received by the cleaning
solution tank 110 having a capacity of 2,000 liters as shown in
FIG. 5. Before being pumped up and reused, the cleaning solution
was filtered by a filter housing (EBF112S6M: manufactured by
Loffler K.K.) containing a nylon monofilament (R100NMO12M bug
filter: manufactured by Loffler K.K., filtering accuracy 100
.mu.m)
[0197] The cleaned pulverized product from which the cleaning
solution was removed was supplied to an air-classification
aspirator system (KF-12: manufactured by Horai K.K.) by the air
blower 114 (DF-5: manufactured by Horai K.K.) and classified into
low-bulk-density foreign matter such as foamed urethane resin and
the other pulverized product.
[0198] The pulverized product passed through the air-classification
aspirator system was dropped onto the magnetic separator 126 (MAGIC
CATCH: manufactured by JMI K.K., residual magnetic flux density 1.3
tesla) to separate ferromagnetic metals.
[0199] Subsequently, the pulverized product was conveyed to the
stock tank 129 by the air blower 127 (DF-1: manufactured by Horai
K.K.). This pulverized product was conveyed at a ratio of about 3
kg/min. from the stock tank 129 to an eddy current type metal
detecting/removing apparatus (MDS-30A: manufactured by Sensor
Technology K.K.), thereby removing metal components. The finally
obtained cleaned pulverized material weighed 38 kg.
[0200] The amounts of moisture and ink sticking to the obtained
cleaned pulverized material were measured by the gravimetric method
and the colorimetric spectroscopy and found to be 0.11 wt % and 10
ppm, respectively. Also, residual metal components were visually
zero.
[0201] The physical property values of this cleaned pulverized
material measured under the same conditions as virgin pellets were
an Izod impact value of 145.0 J/m, an MFR of 42.0 g/10 min., and a
color difference .DELTA.E of 0.35. These physical property values
measured are indicated by S.sub.4 in FIG. 16.
[0202] As shown in FIG. 16, from R.sub.4 to S.sub.4, the Izod
impact value decreased 8.1%, and the MFR increased 3.2%. To give a
recycled plastic material a performance equivalent to that of a
virgin material, it is necessary to make the Izod impact strength
0.8 times or less and the MFR less than 1.2 times. From this
viewpoint, the change rates of the above physical property values
well satisfy the characteristics of a recycled plastic
material.
[0203] The color difference was evaluated by taking account of
color difference variations in the virgin pellet state. In the case
of an ABS resin, .DELTA.E.ltoreq.1.0 was a target. Since the color
difference .DELTA.E obtained was 0.35, this material was found to
be usable in the same manner as the virgin material.
[0204] The residual moisture was also 0.11 wt %, indicating that
adverse effect on plastic caused by hydrolytic properties could be
prevented. The residual ink amount was 10 ppm. From these results,
the recycled plastic material manufactured by this embodiment was
found to have quality equivalent to that of the virgin
material.
[0205] An inkjet printer 11 (BJF-600: available from CANNON INC.)
shown in FIGS. 1 and 2 is currently produced and sold by forming
all of its plastic parts by using virgin materials. This inkjet
printer 11 was manufactured using the cleaned pulverized material
obtained through the above recycling process. More specifically,
the cleaned pulverized material was applied to an upper case 12
(average thickness 2 mm, weight 389 g), a lower case 13 (average
thickness 2 mm, weight 545 g), and an operation cover 14 (average
thickness 2.3 mm, weight 159 g). Consequently, no visual difference
was found between the external appearance and color (hue,
saturation, and lightness) of each of these three parts 12 to 14
and a corresponding part manufactured using the virgin
material.
COMPARATIVE EXAMPLE OF EXAMPLE 4
[0206] A material was recycled following the same procedures as in
the Example 4 except that the plastic supply rate and the cleaning
solution flow rate of the cleaning-cleaning solution removing
apparatus (corresponding to 110 and 113 in FIG. 4) were changed to
2 kg and 10 liters/min., respectively. The obtained cleaned
pulverized material weighed 27 kg.
[0207] The physical property values of this cleaned pulverized
material measured under the same conditions as virgin pellets were
an Izod impact value of 121.5 J/m, an MFR of 45 g/10 min., and a
color difference .DELTA.E of 1.03. These measured physical property
values plus the residual moisture content and the like are
indicated by C.sub.in FIG. 16.
[0208] As shown in FIG. 16, from R.sub.to C.sub., the Izod impact
value decreased 23.0%, and the MFR increased 10.6%. As described
previously, to give a recycled plastic material a performance
equivalent to that of a virgin material, it is necessary to make
the Izod impact strength 0.8 times or less and the MFR less than
1.2 times. The recycled plastic material obtained by changing the
weight ratio of the cleaning solution to the pulverized material
did not satisfy the necessary characteristics.
[0209] Also, the color difference .DELTA.E was 1.03, larger than
the critical value of 1.0, the residual moisture content was 0.55
wt %, and the residual ink amount was 340 ppm. These values and the
other characteristic values measured indicate that the quality
degraded compared to the virgin material.
COMPARATIVE EXAMPLE 2 OF EXAMPLE 4
[0210] A material was recycled following the same procedures as in
the Example 4 except that the filtration accuracy of a filter for a
cleaning solution was changed to 250 .mu.m.
[0211] The physical property values of this cleaned pulverized
material measured under the same conditions as virgin pellets were
an Izod impact value of 117.7 J/m, an MFR of 52 g/10 min., and a
color difference .DELTA.E of 1.16. These measured physical property
values are indicated by C.sub.in FIG. 16.
[0212] As shown in FIG. 16, from R.sub.to C.sub., the Izod impact
value decreased 25.4%, and the MFR increased 27.7%. As described
previously, to give a recycled plastic material a performance
equivalent to that of a virgin material, it is necessary to make
the Izod impact strength 0.8 times or less and the MFR less than
1.2 times. The recycled plastic material obtained by changing the
filtration accuracy of the filter to 250 .mu.m did not satisfy the
necessary characteristics.
[0213] Also, the color difference .DELTA.E was 1.16, larger than
the critical value of 1.0. This indicates that the quality degraded
compared to the virgin material.
EXAMPLE 5
[0214] In each of the above embodiments, the recycled plastic
material obtained by performing the recycling process of a plastic
material according to the embodiment once had physical property
values equivalent to those of the virgin material. In this Example
5, physical properties when the recycling process was performed a
plurality of times will be explained.
[0215] Thermoplastic (ABS resin, true density: 1.05) was recycled
by the same process as in the Example 4. The physical property
values of virgin pellets are indicated by R.sub.in FIG. 17. Also,
the physical property values of a recycled plastic material (to be
referred to as a "one-time recycled material" hereinafter) formed
by repelletizing the cleaned pulverized material obtained by
performing the same recycling process as in the Example 4 one time
are indicated by S.sub.in FIG. 17.
[0216] The physical property values of a recycled plastic material
(to be referred to as a "two-time recycled material" hereinafter)
obtained by repelletizing the one-time recycled material thus
obtained are indicated by S.sub.in FIG. 17. Also, the physical
property values of a three-time recycled material and a five-time
recycled material obtained by similarly repeating the recycling
process are indicated by S.sub.and S.sub., respectively, in FIG.
17.
[0217] As shown in FIG. 17, both the Izod impact value and the MFR
of the one-time recycled material obtained by performing the
recycling process according to the present invention decreased 2.3%
compared to the virgin material (R.sub.). Also, the color
difference was 0.22. These values can be regarded as equivalent to
those in the Example 4. That is, the one-time recycled material was
found to be usable in the same manner as the virgin material.
[0218] Likewise, lowering (deterioration) of the physical property
values of the two-, three-, and five-time recycled materials with
respect to the virgin material (R.sub.) was most significant in
S.sub.; the Izod impact value decreased 7.2%, the MFR increased
2.3%, and the lowering of the color difference was 0.51.
[0219] In the present invention, the definition of a recycled
plastic material having a performance equivalent to a virgin
material is that the Izod impact strength is 0.8 times or less, the
MFR value is less than 1.2 times, and the color difference is 1.0
or less. When this definition is taken into consideration, each
physical property value shows that this recycled plastic material
can be used in the same manner as the virgin material.
[0220] The Rockwell hardness of each recycled material was
substantially the same value as the virgin material. This physical
property value also indicates that the physical property values of
these recycled plastic materials fell in the ranges of prescribed
values.
[0221] That is, the present invention is effective even when the
recycling process is performed a plurality of times.
[0222] In the present invention, laser-engraved thermoplastic is
used as the raw material of a recycled plastic material. Therefore,
the recycling process of this recycled plastic material does not
require any label peeling step. Also, since no paint such as used
in silk screen printing sticks to the material, the recycling
process can be simplified, and deterioration of the hue of the
obtained recycled plastic material can be prevented.
[0223] Furthermore, an electronic apparatus having laser-engraved
thermoplastic parts is disassembled, and thermoplastic parts of an
identical electronic apparatus are molded using thermoplastic
obtained from the thermoplastic parts of the disassembled
electronic apparatus as a raw material. This allows ideal recycling
to be performed.
[0224] Since thermoplastic containing metals is used as the raw
material of a recycled plastic material, not only the metals
contained in the thermoplastic as the raw material but also most
metal pieces which can be mixed when the raw material is pulverized
during the recycling process can be easily removed. Therefore,
contamination is very little, so recycled plastic having high
external appearance quality can be obtained.
[0225] When thermoplastic used in an inkjet apparatus or
thermoplastic to which an ink or its composition adheres is used as
the raw material of a recycled plastic material, this thermoplastic
can be directly reused as thermoplastic parts of the original
inkjet apparatus.
[0226] Since an electronic apparatus is constituted by using the
recycled plastic material described above, the use and spread of
this recycled plastic material can be further promoted.
[0227] When a cleaning solution after thermoplastic is cleaned is
filtered through a filter having a mesh within the range of 25 to
200 .mu.m and the filtered cleaning solution is reused, the problem
of the physical properties of the obtained recycled plastic
material and the problem of clogging of the filter can be solved at
the same time.
[0228] When a cleaning solution contains at least one of an
additive for adjusting the pH concentration and a surfactant, the
cleaning effect can be obtained within a short time.
[0229] When water is used as a cleaning solution and this water
used in cleaning is filtered and reused, the economical efficiency
and the safety of work can be increased compared to the case in
which an aqueous cleaner containing an organic solvent, surfactant,
and builder is used. Additionally, the load on environment can be
minimized by repetitively reusing the cleaning solution.
[0230] When a cleaning solution after cleaning is to be reused, not
only foreign matter removal using a filter but also pH
concentration adjustment are combined into one system. This
improves the cleanness of the cleaning solution when it is reused
and reduces the environmental load.
[0231] By limiting the amount of adhesion of an ink or an ink
components to a recycled plastic material to less than 300 ppm, the
color of the recycled plastic material can be made equal to that
when a virgin material is used.
[0232] Letting I.sub.R and M.sub.R be the Izod impact value and the
melt flow rate, respectively, of a recycled plastic material and
I.sub.V and M.sub.V be the Izod impact value and the melt flow
rate, respectively, of a thermoplastic virgin material before
molding, the quality of this recycled plastic material can be kept
substantially equal to that of the virgin material if
(I.sub.R/I.sub.V)>0.8 and (M.sub.R/M.sub.V)<1.2.
[0233] When external parts of an electronic apparatus are formed by
a recycled plastic material, the product value of the external
appearance does not degrade even with the use of the recycled
plastic material, as well as the physical property values of the
material are maintained. This greatly widens the application of the
recycled material unlike in conventional thermal recycle or cascade
recycle.
[0234] Furthermore, ideal recycling can be performed because
thermoplastic obtained from thermoplastic parts of an ink container
used in an inkjet apparatus is used as a raw material and
thermoplastic parts of an identical inkjet apparatus are molded
using this raw material.
[0235] The present invention is not limited to the above
embodiments and various changes and modifications can be made
within the spirit and scope of the present invention. Therefore, to
apprise the public of the scope of the present invention the
following claims are made.
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