Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-12-10
2004-02-24
Brooke, Michael S. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06695424
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to printing device like a printer and printing method. More specifically, this invention relates to a printing device for ejecting ink onto paper for printing, said device being able to carry out adequate printing according to type of the paper used, a printing method used in said device, and an intermediate holding mechanism having holders to be used for charging paper roll of paper used onto said printing device.
In general, said printing device comprises a plurality of ink flow paths provided in ink jet head and having each nozzle at its front end, ejecting elements for ejecting outwards ink contained in said respective ink flow paths, and electrical controller for electrically controlling said ejection elements.
When using electrostrictive vibrator as said ejecting element, at least a part of walls of said ink flow paths is formed by flexible materials, and said electrostrictive vibrator is mounted on said walls. Said vibrator is electrically controlled by a controller at a predetermined timing, thereby to decrease the cross section of said ink paths to eject outwards ink contained therein, thus printing on paper.
When using thermal head as said ejecting element, a thermal head is provided on walls of said ink flow paths. Particular heating elements of said thermal head are electrically activated at a predetermined printing timing controlled by electrically controlling means, thereby to cause thermal expansion of ink contained in ink flow paths and to eject ink therein onto paper for printing thereof.
Heretofore known type of said printing device having electrostrictive vibrator is described herein below with reference to FIG.
1
and FIG.
2
.
With reference to
FIG. 1
, in front of a cylindrical platen
1
, a pair of carriage shafts
2
,
2
are provided in a direction parallel to the axis of said platen
1
, and a carriage
3
is provided on said carriage shafts
2
in a reciprocating manner. Said carriage
3
has an ink jet unit
4
for full color printing mounted thereon.
As shown in
FIG. 2
, said ink jet unit
4
has thereon
4
ink jet heads
5
corresponding respectively to four colors for full color printing and located each against said platen
1
. Each ink jet head
5
has corresponding nozzle
6
, these nozzles
6
being arranged in parallel manner to each other and opposing to said platen
1
as shown in FIG.
2
. Said ink jet heads
5
are fixed on a head mounting member
7
which is in turn supported by said carriage
3
.
A plurality of inlets
9
containing each auxiliary tanks
8
as buffer tanks for communicating with said respective nozzles
6
provided in said ink jet heads
5
are mounted on said carriage
3
behind said respective ink jet heads
5
. Said respective inlets
9
are communicating with respective ink cartridges
10
of corresponding colors mounted detachably on said carriage
3
.
On the outer side of one end of said platen
10
, there is provided a pump unit
11
which is used for covering said nozzles
6
when not used to prevent ink therein from evaporating and for removing air bubbles or foreign substances stacked in said nozzles
6
. Said pump unit
11
has a casing
13
having an opening
12
on the side of said carriage
3
, said opening
12
having herein a cap body
14
which is reciprocally movable in the direction of said ink jet unit
4
. Said cap body
14
has a plurality of openings
15
formed in a vertical oblong form so as to cover corresponding ink jet heads
5
. Said each opening
15
has therein a gum liner
16
, said liner
16
projecting outside from inside of circumference of said opening
15
to be pressed onto the circumference of corresponding ink jet head
5
in a airtight manner.
Said ink jet heads
5
comprises a plurality of ink flow paths
17
arranged in parallel and communicating with respective nozzles
6
, each of said ink flow paths
17
having thereon corresponding piezo electric elements
18
as electrostrictive vibrators for ejecting ink from the front end of respective nozzles
6
.
On the one hand, said cap body
134
of pump unit
11
has an approximately semispherical protrusion
19
provided on the front upper side thereof, and an air pressure channel
20
is formed from the summit of said protrusion
19
up to the rear side surface of said cap body
14
, a pressurizing means such as pump (not shown) being connected to said air pressure channel
20
. Said respective openings
15
of said cap body
14
is communicated with venting valves (not-shown) through communicating channels
22
. Further, said respective openings
15
are provided with fluid exhausting pipes
23
. These exhausting pipes
23
are connected to corresponding absorbing means such as pumps (not-shown) which absorb remaining portion of ink from respective opening
15
to be stored in a waste ink tank (not-shown).
On the other hand, an air pressure channel
25
is provided on the upper portion of side surface of said head mounting member
7
opposing to said pump unit
11
, said air pressure channel
25
being used for receiving said protrusion
19
in a nozzle touch manner therein to communicating with said pressure air channel
20
when said pump unit
11
covers said ink jet unit
4
. Said air pressure channel
25
is further branched into four branch channels
26
corresponding in number to said ink cartridges
10
. The end portion of said respective branch channels
26
is connected to air pipes
27
communicating respectively with the upper portion of respective ink cartridges
10
.
In the construction as described above of heretofore known printing device, said cap body
14
of said pump unit
11
is first put aside when printing, and said carriage
3
mounting said ink jet unit
4
is run along said platen
1
, while at the same time said piezo electric elements
18
of said nozzles
6
for printing use are driven by feeding electricity thereto on the basis of predetermined printing signals, thereby feeding ink from said ink cartridges
10
through said inlets
9
into said ink flow paths
17
and ejecting through said nozzles
6
onto printing paper on said platen.
In general, the coloring materials used in ink for printing devices are divided into two types, that is dyestuff and pigment. The dyestuff type is superior to said pigment type in the freshness of colors while rather weak when exposed to water and light. On the other hand, said pigment type is inferior to said dyestuff type in freshness of colors while strong against water and light.
With respect to printing paper, there are two types of papers, one type being easier to absorb or receive ink and the other type being rather hard to receive ink. In the former type of paper, absorbed ink is more rapidly diffused, so that the total amount of ink used is less than that of the latter type of paper which is more hard to absorb ink. However, the former type of paper which absorbs more easily ink has inferior to the latter type due to said ink diffusion phenomenon.
Since ink and paper have different physical characteristic as described above, it must be advantageous to use different types of ink and paper in a single printing apparatus thereby to settle different printing conditions for obtaining a wide variety of printing.
However, only one type of ink could be used in the heretofore known printing devices.
This is because the upper limits of electricity feeding conditions such as voltage and frequency for driving ink jet head are different for different types of coloring agent used in an ink even when physical characteristics such as viscosity and surface tension of ink are held constant, so that, if driving pressure and frequency corresponding to the type of coloring agent are not used for driving ink jet head, a constant direction of ink ejection can not be obtained, resulting in a poor printing quality.
Further, with respect to the type of paper used, only a particular type of paper can be used for a particular ink used due to variations of printing quality caused by the absorbing capacity of ink used.
Table 1 show
Aratsu Shuichi
Hakkaku Kunio
Sato Hiroyuki
Sugawara Tatsuo
Sugiyama Koichi
Brooke Michael S.
Quinn, Esq. Charles N.
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