Title: Image recording apparatus and method for recording an image on a recording medium
Abstract: An image recording apparatus records an image on a recording medium by causing a recording head having an arrangement of a plurality of recording elements to conduct its main scanning for the recording medium interrelatedly in the direction opposite to the arrangement of the recording elements. The apparatus comprises a setting device to set the number of main scannings by the recording head; a main scanning device to perform recording by plural numbers of main scannings with respect to one pixel by causing the recording head to conduct its main scannings for the same recording area of the recording medium in accordance with the number set by the setting device; and a sub-scanning device to cause the recording head and the recording medium to be sub-scanned interrelatedly per main scanning in an amount smaller than the width of the arrangement of the recording elements of the recording head. Hence, even if a disabled ejection occurs in one scanning at the time of recording by a multi-scanning, the missing dot is complemented by the following scan to make it possible to obtain an image having no image defects at all times.
Patent Number: 6,932,454 Issued on 08/23/2005 to Suzuki, et al.
| Inventors:
|
Suzuki; Akio (Kanagawa-ken, JP);
Tanaka; Kiyoharu (Tokyo, JP);
Takada; Yoshihiro (Kanagawa-ken, JP);
Miura; Yasushi (Kanagawa-ken, JP);
Ogata; Nobuhiko (Tokyo, JP)
|
| Assignee:
|
Canon Kabushiki Kaisha (Tokyo, JP)
|
| Appl. No.:
|
303827 |
| Filed:
|
November 26, 2002 |
Foreign Application Priority Data
| Feb 26, 1992[JP] | 4-039165 |
| Feb 26, 1992[JP] | 4-039169 |
| Feb 18, 1993[JP] | 5-028915 |
| Feb 18,
1993[JP] | 5-028916 |
| Current U.S. Class: |
347/12; 347/41 |
| Intern'l Class: |
B41J 029/38 |
| Field of Search: |
347/12,15,41,43,37,14
|
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| |
Primary Examiner: Nguyen; Thinh
Assistant Examiner: Huffman; Julian D
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This is a divisional application of application Ser. No. 09/489,910 filed Jan.
24, 2000, now U.S. Pat. No. 6,547, 361, which is a divisional application of application
Ser. No. 08/021,102 filed Feb. 23, 1993, now U.S. Pat. No. 6,036,300, issued Mar.
14, 2000.
Claims
1. An ink jet image recording apparatus for recording an image on a recording
medium using a recording head having a plurality of recording elements arranged
in a predetermined direction, said apparatus comprising:
a main-scan means for relatively main scanning the recording head with respect
to the recording medium in a direction different from the predetermined direction;
and
a shift means for relatively shifting the recording head and the recording medium
by an amount smaller than the width of the recording element arrangement in the
predetermined direction for each main scanning;
a recording control means for controlling the recording head in such a manner
that a region on the recording medium recordable by a single scanning is completed
by a plural number of main scannings, said recording control means dividing image
data into image data corresponding to each of the plural number of main scannings,
and recording being executed by using different recording elements with respect
to each of the plural number of main scannings for the region recordable by a single
recording element in the main-scanning direction; and
a setting means for setting any one of a plurality of different numbers as the
number of main scannings with respect to the area controlled by said recording
control means,
wherein an amount of recording data to be recorded by a single main scanning
becomes smaller and the amount of recording data recorded by each of printing elements
by the single main scanning becomes smaller as a number of main scannings set by
said setting means increases.
2. The image recording apparatus according to claim 1,
wherein said setting means is arranged to set the number of main scannings by
the recording head in accordance with the image data to be recorded.
3. The image recording apparatus according to claim 1, further comprising:
a reading means for reading an image recorded by the recording head,
wherein said setting means is arranged to set the number of the main scans by
the recording head in accordance with the image data read by said reading means.
4. The image recording apparatus according to claim 1,
wherein said main scanning means is arranged to cause recording to be performed
by changing the recording elements to be used for recording for each of the recording
main scans.
5. The image recording apparatus according to claim 1,
wherein said setting means is arranged to set the number of main scans in accordance
with the number of edges detected by an edge detecting means in the image data.
6. The image recording apparatus according to claim 1, further comprising a recording
head having thermal energy transducers for generating thermal energy to cause ink ejection.
7. The image recording apparatus according to claim 6,
wherein said recording control means is arranged to cause one picture element
to be formed by a plurality of inks discharged from the different recording elements
in the plurality of numbers of main scannings.
8. The method of recording an image on a recording medium using a recording head
having a plurality of recording elements arranged in a predetermined direction,
said method comprising:
a main-scanning step for relatively main scanning the recording head with respect
to the recording medium in a direction different from the predetermined direction;
a shifting step for relatively shifting the recording head and the recording
medium by an amount smaller than the width of the recording element arrangement
in the predetermined direction for each main scanning;
a recording control step for controlling the recording head in such a manner
that a region on the recording medium recordable by a single scanning is completed
by a plural number of main scannings, wherein said recording control step includes
dividing image data into image data corresponding to each of the plural number
of main scannings, and recording being executed by using different recording elements
with respect to each of the plural number of main scannings for the region recordable
by a single recording element in the main-scanning direction; and
a setting step for setting any one of a plurality of different numbers as the
number of the main scannings with respect to the area for which said recording
control step is being carried out,
wherein an amount of recording data to be recorded by a single main scanning
becomes smaller and the amount of recording data recorded by each of printing elements
by the single main scanning becomes smaller as the number of main scannings set
in said setting step increases.
9. The method according to claim 8, further comprising the step of:
fixing ink supplied to the recording medium on the recording medium.
10. The method according to claim 9, further comprising the step of:
cleaning the fixed image on the recording medium.
11. The method according to claim 8, further comprising the step of:
applying a preparatory agent to the recording medium before effecting recording
thereon.
12. The method according to claim 8, further comprising the step of dividing
a recording medium on which an image has been recorded into pieces, each of the
pieces having a desired size, and applying a final treatment to the pieces.
13. The method according to claim 12, wherein said setting step is carried out
by setting the number of main scans by the recording head in accordance with the
image data to be recorded.
14. The method according to claim 12, further comprising the steps of:
using a reading means to read an image recorded by the recording head, and
carrying out said setting step by setting the number of the main scans by the
recording head in accordance with the image data read by the reading means.
15. The method according to claim 12, wherein said main scanning step is carried
out so as to cause the recording to be performed by changing the recording elements
to be used for recording for each of the recording main scans.
16. The method according to claim 12, wherein said setting step is carried out
by setting the number of main scans in accordance with the number of edges detected
by an edge detecting means in the image data.
17. The method according to claim 8, wherein said controlling step is carried
out so as to cause one picture element to be formed by a plurality of inks discharged
from the different recording elements in the plurality of numbers of the main scanning.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for recording image and an apparatus
therefor, and a medium recorded by such an apparatus. More particularly, the invention
relates to an image recording method to record an image on a recording medium by
enabling a recording head to scan, and an apparatus therefor, and a medium recorded
by such an apparatus.
2. Related Background Art
There is well known an image recording apparatus of the so-called serial scanning
type wherein a recording head provided with a plurality of recording elements (exothermic
resistive members, nozzles, and the like) is caused to scan for recording. FIG.
2 is a view illustrating a recording method of such a serial scanning type as this,
in which a reference numeral
201 designates an ink jet head with an arrangement
of plural nozzles
202. An image recording is performed per recording width
d corresponding to the arrangement of the nozzles
202 of this ink jet head
201 while the ink jet head
201 is being scanned on a recording sheet
203 in the direction A. Thus, when a recording of the recording width d
is terminated, the recording sheet
203 is shifted in the direction B for
a length corresponding to the recording width d. Then, the ink jet head
201
is again caused to scan in the direction A to perform another image recording for
the recording width d. The recording by such a serial scanning method as this has
an advantage that an image data having a large image surface can be recorded by
a small head. On the other hand, there is a disadvantage that should there be any
nozzles that may be disabled to eject ink or may cause the positions of recorded
dots to be displaced among the nozzles of the head
201, such a portion appears
continuously in the direction A, which tends to create continuous white streaks.
In order to compensate for a disadvantage of the kind, there is proposed a recording
method by multi-scanning which will be described later.
FIG. 3A is a view illustrating such a multi-scanning as this.
An ink jet head
301 has twelve nozzles as designated by reference numerals
1-
1 to
1-
12. These nozzles can be divided into two
portions indicated by reference marks X and Y. Here, the nozzles corresponding
to the X portion are represented by
1-
1 to
1-
6 while
the nozzles corresponding to the Y portion are represented by
1-
7
to
1-
12. At first, a recording by the X portion of the ink jet head
301 is performed with the initial scanning for recording on the portion
of a recording sheet
203 at X′ (the recorded dots by this recording
are represented by X
1 to X
6). Then, in continuation, the recording
sheet
203 is shifted in the direction B in the sub-scanning direction by
an amount d in order to record dots Y
1 to Y
6 (represented by Y′)
using the Y portion of the head
301. By recording in this way, the dots
recorded by the use of the same nozzles are not continuous in the direction A.
Therefore, even if there are nozzles causing the positions of the recording dots
to be displaced, the dots thus recorded do not appear continuously in the direction
A; hence resulting in an advantage that the white streaks in the direction A are
not remarkably noticeable.
Also, the recording density unevenness due to the irregularity of ink ejection
amounts per nozzle is offset by the recording thus performed, and such unevenness
is not remarkably noticeable, either. Also, if the recording duty of the ink jet
head is high, the ink mist is accumulated in the vicinity of the orifice to hinder
the ink ejection in some cases, but when the multi-scanning is performed, dots
are thinned out to enable the number of ink ejections per unit period of time to
be reduced; hence suppressing the generation of the mist. An advantage is brought
about that the disabled ejection due to mist is reduced.
Nevertheless, there are still the images for which the ink ejection
defects causing the white streaks, density unevenness, and mist cannot be prevented
only by the foregoing two-time multi-scanning. For example, if a uniform pattern
should be recorded, the white streaks and density unevenness become extremely conspicuous,
and in some cases, not only the foregoing two-time multi-scanning, three- or four-time
multi-scanning is also required.
Also, for an image requiring a high recording duty, it is insufficient to make
the recording duty a half by the two-time multi-scanning. There are some cases
where it is better to reduce the recording duty to a ⅓ or ¼ by the
three- or four-time multi-scanning.
On the other hand, however, there is a problem that if the number of multi-scannings
is increased, the recording period of time is prolonged that much.
FIG. 3B is a view illustrating another example of such a multi-scanning as this.
The nozzles
302 of the ink jet head
301 can be divided into three
portions designated by reference marks X, Y, and Z. The portions include the nozzles
X-
1 to X-
4, Y-
1 to Y-
4, and Z-
1 to Z-
4,
respectively. At first, with the initial scanning, a recording is performed by
the portion X of the ink jet head
301 for the portion of the recording sheet
203 at X′ (the dots formed by this recording are represented by X-
1
to X-
4). Then, the recording sheet
203 is shifted in the direction
B by d in the sub-scanning direction, and dots Y-
1 to Y-
4 (represented
by Y′) are recorded using the portion Y of the head
301. However,
at this juncture, the portion X of the ink jet head
301 performs its recording
in a position at X. Then, continuously, the recording sheet
203 is again
shifted in the direction B by d for recording by the use of the portion Z of the
ink jet head
301. At this juncture, as shown in FIG. 3B, the recording is
performed in such a manner that the dots recorded by the use of the same nozzle
are not continuous in the direction A. Therefore, even if there are the nozzles
causing the displacement of the recording dots, the dots thus recorded do not appear
continuously in the direction A. The advantage is that the white streaks in the
direction A are not remarkably noticeable.
However, if there are any nozzles performing incomplete ejection, a problem
is still encountered that the white streaks remain as clear image defects, although
the white streaks are less conspicuous by the multi-scanning than by the usual
serial scanning. Particularly when the recording duty is high, the ink mist is
apt to be generated. This type of ink mist is accumulated on the head surface to
cover the nozzles; thus disabling the ink ejection in some cases. A disabled ink
ejection of the kind is different from the genuine nozzle clogging or the like,
and is dependent on the degree of the density of an image. As a result, it occurs
at random in an image or it is often recovered itself; thus making its countermeasure difficult.
Also, in FIG. 3B, when the head is scanned in the direction A to record an
image, the head temperature is increased due to the accumulation of the ejection
driving energy. Thus, the viscosity of ink is lowered and the ejecting amount of
ink is also increased. As a result, the image density is in general higher toward
the termination of recording than at the time of initiating the recording at each
scan. This phenomenon generally presents a problem in any image, but particularly
when output images are joined together to form one image, that is, when the so-called
enlarged continuous copying mode is used, the difference in densities will become
more conspicuous. If a multi-scanning is performed, the number of ink droplets
ejected per unit time per nozzle is reduced as is clear from FIG.
3B. In
the case represented in FIG. 3B, it is reduced to a ⅓ approximately. Therefore,
the head temperature rise is suppressed as compared to the case of using the usual
serial scanning. However, the above-mentioned problem still remains unsolved. Also,
the seriousness of this problem differs depending on the image pattern to be recorded.
In other words, when a pattern having a large image ratio is recorded, this becomes
a serious problem, but when a pattern having a small image ratio is recorded, it
is not so serious a problem.
SUMMARY OF THE INVENTION
The present invention is designed in consideration of the problems related to
the prior art as described above with attention given to a new aspect which has
never been predicted.
It is a first object of the present invention to provide a method for recording
image capable of obtaining a recorded image of a high image quality without lowering
its recording speed unnecessarily by setting the number of multi-scannings in accordance
with the image data to be recorded, and an apparatus therefor, and a medium recorded
by such an apparatus.
Also, it is another object of the first invention to provide an image recording
apparatus, in which a recording head having the arrangement of plural recording
elements is caused to perform its main scanning relatively with respect to a recording
medium in the direction different from the foregoing arrangement to record the
image on the recording medium, comprising the following:
setting means to set up a number of the main scannings by the aforesaid recording head;
main scanning means to cause the aforesaid recording head to perform its main
scannings for a same recording area in accordance with the main scanning number
set up by the aforesaid setting means in order to perform recording by the number
of plural main scannings per pixel; and
sub-scanning means to cause the aforesaid recording head and the aforesaid
recording medium to be relatively sub-scanned per the aforesaid main scanning for
an amount smaller than the width of the area where the recording elements of the
recording head are arranged.
Also, it is a second object of the present invention to provide a method for
recording image capable of obtaining a recorded image having a high image quality
without any image defects, and an apparatus therefor, and a medium recorded by
such an apparatus.
Further, it is another object of the second invention to provide an image
recording apparatus to record image on a recording medium by causing a recording
head having a plurality of recording elements to relatively scan the recording
medium, comprising the following:
recording means to perform recording by causing the aforesaid recording
head to relatively scan the recording area of the aforesaid recording medium for
plural numbers;
reading means to read a recorded image which is recorded on the aforesaid
recording medium by relatively scanning the recording area of the aforesaid recording
medium together with the aforesaid recording head at the time of the execution
of recording by the aforesaid recording means;
determining means to determine an area having a defective recording by
comparing the recorded image read by the aforesaid reading means with the information
of the image to be recorded essentially; and
complementary recording means to perform a complementary recording
in the subsequent scanning by the aforesaid recording head for the area having
the defective recording determined by the aforesaid determining means.
Also, it is other objects of the present invention to provide a method for
recording image on a recording medium using these image recording apparatuses,
and a medium recorded as a result thereof.
It should be noted that the term "recording" used in the present specification
and claims includes a meaning of "printing" and signifies in a broad sense providing
an image on a recording medium such as cloths made of cotton or silk, etc. and
paper. It should be also noted that the language "recording" does not limit the
scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram schematically showing the structure of the principal
part of a printing apparatus according to a first embodiment of the first invention.
FIG. 2 is a view illustrating a recording state of a conventional recording
head of a serial recording type.
FIGS. 3A and 3B are views illustrating multi-scanning recording methods.
FIG. 4 is a flowchart showing the control process in a printing apparatus according
to the first embodiment of the first invention.
FIG. 5 is a flowchart showing the process according to a second embodiment of
the first invention.
FIG. 6 is a block diagram schematically illustrating the structure of an image
determining unit according to a third embodiment of the first invention.
FIG. 7 is a view illustrating a multi-scanning according to another embodiment
of the first invention.
FIG. 8 is a block diagram showing a structural example of the system of a recording
apparatus according to the present invention.
FIG. 9 is a view schematically showing a mode of a recording apparatus provided
with a two-staged head preferably suitable for the present invention.
FIG. 10 is a partially cut off perspective view showing a structural example
of the principal part of an ink jet recording apparatus according to the present invention.
FIG. 11 is an enlarged perspective view showing the structure of the vicinity
of the head unit of the recording apparatus shown in FIG. 9.
FIG. 12 is a block diagram illustrating an embodiment of an ink jet recording method.
FIG. 13 is a view illustrating the recording operation of a fourth embodiment
of the second invention.
FIG. 14 is a block diagram schematically showing the structure of a printing
apparatus according to the fourth embodiment of the second invention.
FIG. 15 and FIG. 16 are flowcharts showing the recording process in the
printing apparatus according to the fourth embodiment of the second invention.
FIG. 17 is a view illustrating the recording operation of a fifth embodiment
of the second invention.
FIG. 18 is a view illustrating the recording operation of a sixth embodiment
of the second invention.
FIG. 19 is a block diagram schematically showing the structure of a printing
apparatus according to the sixth embodiment of the second invention.
FIG. 20 and FIG. 21 are flowcharts showing the recording process in a
printing apparatus according to the seventh embodiment of the second invention.
FIG. 22 is a view illustrating the recording operation of a printing apparatus
according to an eighth embodiment of the second invention.
FIG. 23 is a block diagram showing the structure of the principal part of a
printing apparatus according to a ninth embodiment of the second invention.
FIG. 24 is a view showing the y correction characteristics in the y control
unit of a printing apparatus according to the ninth embodiment of the second invention.
FIG. 25 is a block diagram showing the structure of the principal part of a
printing apparatus according to a tenth embodiment of the second invention.
FIG. 26 is a cross sectional view showing a recording apparatus according to
an eleventh embodiment.
FIG. 27 is a perspective view illustrating the recording unit of a recording
apparatus according to the eleventh embodiment.
FIG. 28 is a perspective view illustrating the monitor unit of an recording
apparatus according to the eleventh embodiment.
FIG. 29 is a cross sectional view showing the recording head and ink supply
system shown in FIG. 27.
FIG. 30 is a block diagram schematically showing the structure of a recording
apparatus according to the eleventh embodiment.
FIG. 31 is a view showing an example of the image defect due to the defective
ejection of a nozzle.
FIG. 32 is a flowchart showing the recording process in a printing apparatus
according to the eleventh embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, with reference to the accompanying drawings, the detailed
description will be made of the preferable embodiments according to the present invention.
FIG. 8 is a block diagram showing an example of the fundamental structure which
is applied to an ink jet recording apparatus exemplified as an image recording
apparatus according to the present invention. This ink jet recording apparatus
is structured as a system roughly comprising:
an image reading device
1 to read an original image produced by a designer
and others and convert this original image into the original image data which represent
the original image by electric signals;
an image processing unit
2 to receive the original image data from the
image reading device
1 for processing and output them as the image data; and
an image recording unit
3 to perform recording on cotton, silk, and other
recording media in accordance with the image data produced by the image processing
unit
2. In the image reading device
1, the original image is read
by a CCD image sensor. In the image processing unit
2, the data are produced
from the inputted original image data in order to drive the ink jet recording unit
A-
2 (FIG. 9) which ejects four color ink materials, magenta (abbreviated
as M), cyanogen (abbreviated as C), yellow (abbreviated as Y), and black (abbreviated
as Bk), which will be described later. When the data are produced, there are performed
an image processing for the reproduction of the original image with ink dots; the
distribution of colors to determine the color tone; the modification of the layout;
and the rearrangement of the sizes for and the selection of the patterns by enlargement,
contraction, or the like. In the image recording unit
3, recording is performed
by the ink Jet recording unit A-
2. The ink jet recording unit A-
2
causes fine ink droplets to fly toward the recording medium for recording by the
adhesion of these ink droplets to the recording medium.
FIG. 10 is a perspective view showing an example of an ink jet recording apparatus
to be used for the present invention.
At first, an ink jet recording unit
100 is structured by a frame
6,
two guide rails
7 and
8, an ink jet head
9 and a carriage
10 to carry the head, an ink supply device
11 and a carriage
12
to carry it, and a head recovery device
13 and an electric power supply
system
5 according to the broad classification of the constituents. The
ink jet head
9 (hereinafter simply referred to as head) includes a plurality
of nozzle arrays and transducers to transduce electric signals into the ink ejection
energy, and has a mechanism to selectively eject ink from the nozzle arrays in
accordance with the image signals transmitted from an image processing unit (not shown).
The foregoing head is a recording head which ejects ink by the utilization of
thermal energy, and is provided with the thermal energy transducers which generate
thermal energy given to ink. It is preferable to use a head wherein the ink is
caused to change its state by the thermal energy given thereto by the foregoing
thermal energy transducers to eject it from the discharging ports on the basis
of the foregoing change of state thus generated.
The ink supply device
11 stores ink and supplies it to the head as required,
and has an ink tank, an ink pump, and the like which are not shown. The supply
device
11 and the head
9 are connected by ink supply tubes
15,
and usually, the ink is automatically supplied to the head
9 by a capillary
phenomenon by the amount to be ejected. Also, in operating a head recovery which
will be described later, the ink is forcibly supplied to the head
9 using
the ink pump.
The above-mentioned head
9 and ink supply device
11 are respectively
mounted on a carriage
10 and a carriage
12, and are structured to
reciprocate along the guide rails
7 and
8 by a driving device which
is not shown.
The head recovery device
13 is provided at a position opposite to the
head
9 in the home position (standby position) of the head
9 in order
to maintain the ink ejection stability of the head, and is able to advance or retract
in the direction indicated by an arrow A. More specifically, it will operate as
given below.
At first, the capping of the head
9 (capping operation) is performed in
the home position in order to prevent ink in the nozzles of the head
9 from
being evaporated when the head is at rest, or to execute a function to collect
the exhausted ink when an operation (pressurized recovery operation) is performed
to cause ink to be exhausted forcibly from the nozzles by giving pressure to the
ink passage in the head by the use of a pump in order to remove bubbles and dust
particles in the nozzles before starting an image recording, or an operation (suction
recovery operation) is performed to suck and exhaust ink forcibly from the nozzles.
The electric power supply system
5 includes a control unit to control
the overall sequence of the power unit and ink jet recording unit. A cloth
16
is fed for a given amount in the sub-scanning direction (direction indicated by
an arrow B) by a feeding device which is not shown for each time a recording is
performed for a given length with the shifting of the head
9 along the carriage
7 in the main scanning direction. Thus, the image formation is carried out.
In FIG. 10, the portion
17 indicated by slanted lines represents the portion
where the recording has been made.
In this respect, it may be possible for the recording head
9 to use an
ink jet recording head for a monochrome recording, the plural recording heads to
perform recording in ink of different colors for a color recording, or plural recording
heads to perform recording in a variable density ink of a same color among others.
Also, irrespective of the recording means and the structures of the ink tank,
it is possible to apply various types of heads such as a cartridge type wherein
a recording head and an ink tank are formed integrally, or a type which is structured
by connecting the separately formed recording head and ink tank by the ink supply tubes.
Furthermore, it is possible to obtain images of a high quality on a
recording medium having an extremely low water absorption by implementing the present
invention in a recording apparatus of a mode set forth below. FIG. 9 is a view
schematically showing a recording apparatus particularly preferable for a method
of the present invention. This recording apparatus roughly comprises a cloth supply
unit B to feed a rolled cotton cloth, silk, or other recording media which are
preliminarily processed for printing; a main unit A to precisely feed the cloth
thus carried line by line for printing by the ink jet head; and a winding unit
C to dry and wind the printed cloth. The main unit A further comprises a precision
feed unit A-
1 for cloth including a platen, and a printing unit A-
2.
FIG. 11 is a perspective view showing the structure of the printing unit A-
2
in detail.
Hereinafter, taking as an example a case of printing a preliminarily
processed cloth as a recording medium, the operation of this apparatus will be described.
A rolled cloth
36 which is preliminarily processed is fed to the cloth
supply
unit and then to the main unit A. In the main unit, a thin endless belt
37
is tensioned around a driving roller
47 and a winding roller
49,
which is step driven precisely. The driving roller
47 is step driven directly
by a high resolution stepping motor (not shown) to step feed the belt by such a
stepping amount thereof. The cloth
36 thus fed is pressed and tensioned
by a pressing roller
40 to the surface of the belt
37 which is backed
up by the winding roller
49.
The cloth
36 thus step fed by the belt is positioned by the platen
32
arranged behind the belt in the first printing unit
31; thus being printed
by the ink jet head
9 from its surface side. Each time one line of printing
is terminated, the cloth is step fed for a predetermined amount. Then, it is dried
from its surface by the heated draft produced by a hot plate
34 from the
behind the belt and supplied or exhausted through a hot air duct
35. Subsequently,
superposed printing is performed in the second printing unit
31′
in the same method as in the first printing unit. The cloth printed completely
is drawn apart and guided to a post drying unit
46 comprising the hot plate
and hot air duct as in the foregoing drying unit where it is again dried; thus
being guided by a guide roller
41 to the winding roller
48 for winding.
The wound cloth is removed from the apparatus and processed as a finished product
through a batch processing of coloring, cleaning, drying, and the like.
In accordance with FIG. 1, the details of the printing unit A-
2 will be described.
A preferable mode here is such that by the head in the first recording unit,
the
information is recorded while thinning the dot numbers, and then, after the drying
process, the ink droplets are ejected by the head in the second printing unit to
complement the information which has been thinned in the first printing unit.
In FIG. 11, the cloth
36 which is a recording medium is mounted on the
belt
37 under tension and is being step fed in the upper direction in FIG.
11. For the first printing unit
31 located in the lower part of FIG.
11, a first carriage
44 is provided with a mounted ink jet head for Y, M,
C, Bk, and special colors S
1 to S
4. The ink jet head (recording head)
used for this embodiment is a head having the elements which generate the thermal
energy to give the film boiling utilized as energy to ink to cause it to be ejected,
and in such a head, 128 discharging ports are arranged with a density of 400 DPI (dot/inch).
On the downstream side of the first printing unit, there are arranged a hot plate
34 to apply heat from the back side of the belt, and a drying unit
45
comprising a hot air duct
35 to effect drying from the surface side. The
thermal conductive surface of the hot plate
34 is pressed to the heavily
tensioned endless belt
37 to heat the feeding belt
37 strongly from
its behind by a high pressure steam running at a high temperature in the hollow
inside thereof. The conveyer belt
37 heats the mounted cloth
36 by
the thermal conductivity directly and effectively. On the inner side of the hot
plate, fins
34′ are arranged to collect heat to converge it to the
back side of the belt efficiently. The side which is not in contact with the belt
is covered with a heat shielding member
43 in order to prevent any loss
due to heat radiation.
On the surface side, a drying hot air is blown from a supply duct
30 on
the downstream side to supply lower moisture air to the cloth being dried for the
enhancement of its effect. Then, the air containing a sufficient amount of moisture
running in the direction opposite to the conveying direction of the cloth is drawn
into a suction duct
33 by the suction which is far greater than the drafting
to prevent any leakage of the evaporated water so as not to form dews on the surrounding
mechanical devices. The supply source of the heated air is provided on the rear
side in FIG. 10, and the suction is conducted from the front side. The difference
in pressure between the drafting outlet
38 and the suction inlet
39
against the cloth is arranged to be even all over the area in the longitudinal
direction. The air drafting and suction units are offset to the downstream side
from the center of the hot plate arranged on the back sides thereof so that the
air can be applied to the location which is sufficiently heated. Hence, in the
first printing unit
31, a great quantity of water contained in ink received
by the cloth including the thinning agent is dried intensively.
On the downstream side (upward), the second printing unit
31′ is
arranged. The second printing unit is formed with a second carriage
44′
of the same structure as the first carriage.
Now, the description will be made of a preferable example of a recording method
for the ink jet printing. FIG. 12 is a block diagram illustrating the printing
method. As shown in FIG. 12, a cloth is dried (including natural drying) after
the ink jet printing process. Then, continuously, the dyestuffs on the clothing
fiber are dispersed, and a processing is effected to fix the dyestuffs to the fiber
by reaction. By this processing, it is possible to obtain a sufficient coloring
capability and durability by the fixation of the dyestuffs.
These processes of the diffusion and reactive fixation can be executed by a
conventional method. A steaming method can be executed, for example. Here, in this
case, it may be possible to provide an alkaline treatment to the cloth in advance
before the printing process.
Then, in the post treatment process, the dyestuffs that have not shown any
reaction and the substances that have been used in the preparatory process are
removed. Lastly, the defect correction, iron finishing, and other finishing adjustment
treatments are effected before the completion of the recording.
As recording media that can be used for the recording by an image recording apparatus
according to the present invention, it is possible to use cotton, silk, wall papers,
papers, OHP film, and others. Particularly, for a recording medium having a low
water absorption, such as cotton, silk, and wall papers, the present invention
is preferably suitable.
Here, in the present specification, the cotton and silk are meant to include
every woven fabric, non-woven fabric, and other cloths irrespective of the raw
materials, the methods for weaving and knitting.
Also, in the present specification, the wall papers include the adhesive materials
for wallpapers which use papers, cloths, or polychloride vinyl and other synthetic
resin sheets as its raw materials.
Particularly, for the ink jet printing, the cloths are to meet the
following requirements:
(1) Colors should come out on ink in a sufficient density.
(2) Dye fixation factor is high for ink.
(3) Ink must be dried quickly on the cloth.
(4) The generation of irregular ink spread on the cloth is insignificant.
(5) The cloth should have an excellent capability of being fed in an apparatus.
In order to satisfy these capability requirements, it may be possible to give
a preparatory treatment as required to the cloth to be used for printing. For example,
in Japanese Patent Laid-Open Application No. 62-53492, the cloths having an ink
receptacle layer are disclosed. Also, in Japanese Patent Publication No. 3-46589,
there are proposed the cloths which contain reduction preventive agents or alkaline
substances. As an example of such preparatory treatment as this, it is also possible
to name a process to allow the cloth to contain a substance selected from an alkaline
substance, water soluble polymer, water soluble metallic salt, or urea and thiourea.
As an alkaline substance, there can be named, for example, hydroxide alkali metals
such as sodium hydroxide, potassium hydroxide; mono-, di-, and tori-ethanol amine,
and other amine; and carbonate or hydrogen carbonate alkali metallic salt such
as sodium carbonate, potassium carbonate, and sodium hydrogen carbonate. Furthermore,
there are organic acid metallic salt such as calcium carbonate, barium carbonate
or ammonia and ammonia compounds. Also, the sodium trichloroacetic acid and the
like which become an alkaline substance by steaming and hot air treatment can be
used. The alkaline substance which is particularly suitable for the purpose can
be the sodium carbonate and sodium hydrogen carbonate which are used for dye coloring
of the reactive dye stuffs.
As water soluble polymer, there can be named starchy substances such as corn
and
wheat; cellulose substances such as carboxyl methyl cellulose, methyl cellulose,
hydroxy ethel cellulose; polysaccharide such as sodium alginic acid, gum arabic,
locasweet bean gum, tragacanth gum, guar gum, and tamarind seed; protein substances
such as gelatin and casein; and natural water soluble polymer such tannin and lignin.
Also, as synthetic polymer, there can be named, for example, polyvinyl alcoholic
compounds, polyethylene oxide compounds, acrylic acid water soluble polymer, maleic
anhydride water soluble polymer, and the like. Among them, polysaccharide polymer
and cellulose polymer should be preferable.
As water soluble metallic salt, there can be named the pH4 to 10 compounds which
produce typical ionic crystals, namely, halogenide compounds of alkaline metals
or alkaline earth metals, for example. As a typical example of these compounds,
NaCl, Na
2SO
4, KCl and CH
3COONa and the like can
be named for the alkaline metals, for example. Also, CaCl
2, MgCl
2,
and the like can be named for the alkaline earth metals. Salt such as Na, K and
Ca should particularly be preferable.
In the preparatory process, a method is not necessarily confined in order to
enable
the above-mentioned substances and others to be contained in a cloth, but usually,
a dipping method, padding method, coating method, spraying method, and others can
be used.
Moreover, the printing ink given to the ink let printing cloth merely adheres
to it when printed on the cloth. Therefore, it is preferable to perform a subsequent
reactive fixation process (dye fixation process) for the dye stuffs to be fixed
on the cloth. A reactive fixation process such as this can be a method publicly
known in the art. There can be named a steaming method, HT steaming method, thermofixing
method, for example. Also, alkaline pad steaming method, alkaline blotch steaming
method, alkaline shock method, alkaline cold fixing method, and the like can be
named when a cloth is used without any alkaline process being given in advance.
Further, the removal of the dye stuffs which have not reacted and the substance
used in the preparatory process can be performed by cleaning by the publicly known
method in the art subsequent to the above-mentioned reactive fixation process.
In this respect, it is preferable to conduct a conventional fixing treatment at
the time of this cleaning.
The above-mentioned structure of the ink jet recording apparatus, and the preparatory
and post processes for the cloth are preferably applicable to first and second
inventive concepts set forth below.
Now, the description will be made of the first inventive concept in detail.
FIG. 1 is a block diagram schematically showing the structure of the principal
part of a printing apparatus according to the present embodiment. FIG. 4 is a flowchart
showing the control process by a control unit
101 of this apparatus.
In FIG. 1, a reference numeral
101 designates a control unit which performs
the overall control of the printing apparatus. This control unit comprises a CPU
110 such as a microprocessor; a ROM
111 storing the control program
for the CPU
110 as represented in the flowchart shown in FIG.
4 and
various data; a RAM
112 used as a work area for the CPU
110 to store
various data provisionally, and others.
A reference numeral
102 designates a head driver to drive the recording
head (ink jet head)
301;
103 and
104, motor drivers which
drive a carriage motor
105 and a feed motor
106 to be rotated, respectively,
in accordance with instructions from the control unit
101; and
107,
a setting switch operated by a user to set the number of multi-scannings.
The user observes the designed patterns to be printed through the monitor screen
(not shown) or in the form of its original. If it is determined that this image
to be printed tends to create conspicuous unevenness and streaks due to the uneven
patterns thereof, or it tends to cause defective ejection from the nozzles of the
recording head due to ink mist resulting from the highly densified portion in the
image, the user operates the setting switch
107 to make the number of the
multi-scanning to be increased. A case where the multi-scanning is set for two
or three times will be described, for example.
Now, with reference to a flowchart shown in FIG. 4, the description will be
made of the recording process by a printing apparatus according to the present embodiment.
At first, in step S
1, the number of the multi-scannings set by the setting
switch
107 is read, and in step S
2, it is determined whether such
a number is 2 or 3. Here, in this respect, a case where the number of multi-scannings
is 2 or 3 for the sake of convenience, but the process can be achieved in the same
manner even when the numeral values are other than the numbers mentioned as a matter
of course.
When the set number is 3, the sequence will proceed to step S
3 to divide
the nozzles of the recording head
301 shown in FIG. 3 into three. When the
three-time multi-scanning is performed, for example, the twelve nozzles of the
ink jet head
301 are divided into three groups of
1-
1 to
1-
4,
1-
5 to
1-
8, and
1-
9 to
1-
12.
Then, in step S
4, using the nozzles
1-
1 to
1-
4,
the first, fourth, and seventh images of the image data in the direction A are
recorded at intervals of two data. This process is repeated until the recording
for one scanning portion is terminated. Then, when the recording for one scanning
is terminated, the sequence will proceed to step S
6 in which the recording
sheet
203 is shifted in the direction B for an amount of 2d/3, and the carriage
is returned to the home position for a carriage return.
Subsequently, the sequence will proceed to step S
7 to record
the second, fifth, and eighth images of the image data in the direction A at intervals
of two data usin
