EP0816109A1 - Ink jet recording apparatus and head gap retaining mechanism for use therein - Google Patents
Ink jet recording apparatus and head gap retaining mechanism for use therein Download PDFInfo
- Publication number
- EP0816109A1 EP0816109A1 EP97304272A EP97304272A EP0816109A1 EP 0816109 A1 EP0816109 A1 EP 0816109A1 EP 97304272 A EP97304272 A EP 97304272A EP 97304272 A EP97304272 A EP 97304272A EP 0816109 A1 EP0816109 A1 EP 0816109A1
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- EP
- European Patent Office
- Prior art keywords
- ink jet
- printing medium
- ink
- recording apparatus
- jet recording
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J25/00—Actions or mechanisms not otherwise provided for
- B41J25/304—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface
- B41J25/308—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface with print gap adjustment mechanisms
- B41J25/3082—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface with print gap adjustment mechanisms with print gap adjustment means on the print head carriage, e.g. for rotation around a guide bar or using a rotatable eccentric bearing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J25/00—Actions or mechanisms not otherwise provided for
- B41J25/304—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface
- B41J25/308—Bodily-movable mechanisms for print heads or carriages movable towards or from paper surface with print gap adjustment mechanisms
Definitions
- the present invention relates to an ink jet recording apparatus that is equipped with an ink jet cartridge for jetting a recording liquid onto a printing medium and thereby causing it onto the printing medium to thereby perform recording and a gap retaining mechanism for retaining the gap between the ink jet cartridge and the printing medium, which gap retaining mechanism is used in the ink jet recording apparatus.
- An ink jet recording method is one which generates droplets of ink and makes flight thereof and causes attachment of a part or the whole thereof onto a printing medium such as a sheet of paper to thereby perform recording, by the use of various recording liquid jetting systems such as a system wherein ink is attracted and jetted by electrostatic force, a system wherein mechanical vibration or displacement is imparted to recording liquid with the use of a piezoelectric element, or a system wherein recording liquid is heated and bubbled whereby the resulting pressure is utilized.
- various recording liquid jetting systems such as a system wherein ink is attracted and jetted by electrostatic force, a system wherein mechanical vibration or displacement is imparted to recording liquid with the use of a piezoelectric element, or a system wherein recording liquid is heated and bubbled whereby the resulting pressure is utilized.
- an ink jet cartridge 201 is disposed with a necessary gap (g) being kept between itself and a platen 202.
- the platen 202 is made rotatable by being made using a rubber roller or is formed using a highly slidable resin into a somewhat curved convex configuration and this platen is in a positional relation wherein a printing medium 203 is in contact with the apex of the convex portion of the platen.
- the printing medium 203 is conveyed up to a printing zone that is composed of the ink jet cartridge 201 and the platen 202 by being clamped between a capstan 204 and a pinch roller 205.
- the capstan 204 is made using a material of high rigidity such as stainless steel and the pinch roller 205 is made using an elastic material such as rubber.
- the recording apparatus operates in such a way as to receive, according to the instructions from the controller 305, the image data input from an external device 301 such as a personal computer, perform data conversion such as color conversion and edge emphasis in the image processing circuit 304, and cause ink to be jetted from an ink jet head unit 306 in correspondence with the converted data to thereby cause an image to be formed on the printing medium 307.
- the image that is formed is generally two-dimensional and the ink jet openings of the ink jet head unit 306 are disposed one-dimensionally, in order to perform printing over a relevant entire region it becomes necessary to use paper feeding means and ink jet head carrying means (not illustrated) which are for the purpose of sequentially feeding both of the head unit 306 and printing medium 307 in directions perpendicular to each other to thereby repeat the printing operation.
- paper feeding means and ink jet head carrying means (not illustrated) which are for the purpose of sequentially feeding both of the head unit 306 and printing medium 307 in directions perpendicular to each other to thereby repeat the printing operation.
- this end has hitherto been accomplished by mounting a guide roller 211 onto a head carrier 209 having mounted thereon an ink jet cartridge 201 and sliding the guide roller 211 on a guide rail 208.
- the guide rail 208 is fixed to a frame member by being fastened thereto by means of screws or the like.
- a gap distance (g) has the same degree of variation as that of (l).
- assembling tolerances such as the mounting tolerance of the guide rail 208
- the degree of variation of the gap (g) becomes inconveniently a relatively large value of, for example, 0. 1 to 0. 2 mm or so.
- the force that acts on the ink droplet 505 is proportional to the field intensity between the ink jet cartridge 501 and the opposing electrode 505. Accordingly, the variation in the gap distance (g) is in direct correspondence with the variation in the force that acts on the ink droplet 505, which results in the deterioration of the image quality due to the variation in the printing conditions.
- an ink jet recording apparatus comprising ink jetting means for jetting a recording liquid onto a printing medium in correspondence with input image data, characterised by gap retaining means for maintaining a distance between the printing medium and the ink jetting means to be at a predetermined value, paper feeding means for for feeding the printing medium and head carrying means for carrying the ink jetting means in a direction that is substantially perpendicular to feeding direction of the printing medium.
- a gap retaining mechanism of an ink jet recording apparatus comprising ink jetting means for jetting a recording liquid onto a printing medium in correspondence with input image data, paper feeding means for carrying the ink jetting means in a direction in which the printing medium is fed, characterised by a roller member rotatably mounted on the ink jet means or head carrying means and moveable in such a way as to rotate on the printing medium to maintain a distance between the printing medium and the ink jetting means to be at a fixed value.
- a guide roller is mounted on an ink jet cartridge or head carrier for carrying the ink jet cartridge and this guide roller is disposed such that its mounting position is situated on a surface of the ink jet cartridge or head carrier which is upstream in the paper feeding direction, whereby the guide roller runs on the surface of the printing medium but not runs on the guide rail as in the prior art.
- the ink jet cartridge follows, while being in contact with, the surface of the printing medium, with the result that only if the dimensions are strictly determined with regard to only the circularity of the guide roller and the eccentricity thereof at the time of mounting thereof, even when the machining precision of the remaining constituent parts is decreased, the variation degree of the gap distance can be maintained to be at an appreciably small value.
- the guide roller runs on the printing surface on a side that is upstream in the paper feeding direction, the guide roller does not touch the ink after printing has been performed and therefore does not stain the printed surface.
- Fig. 1 is a side view illustrating an embodiment wherein in an ink jet recording apparatus according to the present invention a guide roller has been provided on a head carrier.
- Fig. 2 is a side view illustrating a printing portion in particular of a conventional ink jet recording apparatus.
- Fig. 3 is a block diagram illustrating the operation of the ink jet recording apparatus.
- Fig. 4 is a schematic diagram illustrating the relationship of the distance between the sliding surface of the guide rail and a base and the distance between the printing surface and the base, with the head position as viewed in the main scanning direction.
- Fig. 5 is a schematic diagram illustrating the operation that is performed when applying an electric field to an electrically charged ink droplet.
- Fig. 6 is an upper surface view illustrating the operation of the ink jet recording apparatus according to the present invention.
- Fig. 7 is a schematic diagram illustrating that the gap distance can be maintained to be fixed in the ink jet recording apparatus according to the present invention.
- Fig. 8 is a schematic diagram illustrating an embodiment of cleaning means for cleaning the guide roller of the ink jet recording apparatus according to the present invention.
- Fig. 9 is a schematic diagram illustrating another embodiment of the cleaning means for cleaning the guide roller of the ink jet recording apparatus according to the present invention.
- Fig. 10 is a side view illustrating an embodiment wherein in the ink jet recording apparatus according to the present invention the guide roller has been provided on the ink jet cartridge. And,
- Fig. 11 is a side view illustrating an embodiment wherein in the ink jet recording apparatus according to the present invention the guide roller and cleaning means have been provided on the ink jet cartridge.
- the guide roller is provided to the ink jet cartridge or head carrier and this guide roller is made to run on the surface of the printing medium and, in addition, this guide roller is disposed on a side that is upstream in the printing direction. Further, means for cleaning the outer-peripheral surface of the guide roller has been mounted on the ink jet cartridge or head carrier.
- an ink jet cartridge 101 is structured such that the ink jet cartridge 101 is removably mounted on a head carrier 109, whereby when the ink has been used up, the ink jet cartridge as a whole is replaced by a new cartridge or otherwise is demounted once and, after ink is supplemented, is mounted again.
- the head carrier 109 is arranged to be able to make its reciprocating movements in directions perpendicular to the paper surface and make its rocking movements about a guide shaft.
- This reciprocating movement is performed with a pulse motor (not illustrated) or the like in order to be synchronized with transfer of data to the ink jet cartridge 101. Also, since the center of gravity of the entire head carrier is located on the left side of the guide shaft 110, the moment acts on the entire head carrier due to the gravitational force in the counterclockwise direction, which results in that a guide roller 111 runs on the surface of a printing medium 103 in such a way as to follow this surface while being in contact therewith.
- an opposing electrode 113 which is formed to have a size that can cover not only a region permitting it to oppose the ink jet surface of the ink jet cartridge 101 but also a region permitting it to oppose even a position at which it opposes the guide roller 111.
- Fig. 6 is an illustration wherein the printing portion that is constructed in Fig. 1 has been viewed from above.
- the right side of a printing medium 603 as viewed from the head carrier 609 is in a state where print images are already formed.
- the head carrier 609 is designed so that the home position thereof is located at a point (E).
- the printing medium 603 is fed from a pinch roller 605 side and is conveyed in a direction (C).
- an ink jet cartridge 601 and the head carrier 609 are so arranged as to be able to make their reciprocating movements in directions (A) and (B).
- the rolling direction of the guide roller 611 (the directions (A) and (B)) and the feeding direction of the printing medium (the direction (C)) intersect each other at right angles, unless when the printing medium 603 is fed the head carrier 609 is retracted to the home position (E), the conveying operation of the printing medium 603 ceases to be performed smoothly, with the result that according to cases, the paper feeding precision is inconveniently decreased.
- Fig. 7 The illustration that is made of Fig. 6 from the side of the pinch roller 605 is presented in Fig. 7.
- the configuration of the opposing electrode 713 is not always completely flat and has more or less an undulation or inclination.
- the opposing electrode has an undulation of ⁇ at maximum, and this value is considered to be from approximately 0. 3 to 0. 6 mm or so with respect to the printing of an A3 paper having a printing width/short side of 210 mm. Since as explained in connection with Fig.
- the head carrier is given a clearance that permits it to rotate about the guide shaft, if the vertical variation of the head carrier is to an extent of from approximately 0. 3 to 0. 6 mm or so, the head carrier 709 can run on the surface of the printing medium 703 while being rocked about the guide shaft 710 and following this surface configuration thereof. Since the ink jet cartridge 701 is mounted on the head carrier 709, the distance between the ink jet surface of the head and the opposing electrode 713 is always maintained to be fixed for the above-mentioned reasons.
- the gap roller such as the guide roller for maintaining the gap is arranged to run on the surface of the printing medium as mentioned above, there is supposed also a case where as the number of printed sheets of paper increases the outer-peripheral surface of the gap roller becomes stained due to the paper dust powder. In such a case, it is effective for the gap roller to have a cleaning mechanism such as that which is illustrated in Fig. 8.
- the ink jet recording apparatus of Fig. 8 differs from the preceding one in the respect of being structured such that as illustrated in Fig. 8(b) an arm 812 is extended from an ink jet cartridge 801 and, as illustrated in Fig.
- a plate spring 814 and rubber blades 815 and 816 are mounted on a forward end of this arm 812.
- the printing is performed while the head carrier 809 is being moved in the direction of (A)
- the guide roller 811 is rotated in the direction of (C)
- the stains that have attached onto the outer-peripheral surface of the guide roller 811 are scratched away by the rubber blades 815.
- the cleaning is performed by the rubber blade 816 that is opposite to that which has been mentioned above.
- the cleaning blades are also replaced simultaneously, defective cleaning is prevented due to the wear of the rubber blades.
- FIGs. 9(a) and 9(b) Another embodiment of this cleaning mechanism is illustrated in Figs. 9(a) and 9(b).
- This embodiment differs from Fig. 8 in that scratching-away of the stains is performed not by the rubber blades but by pressing a cleaning roller 914 such as that which has been formed using a foamable sponge or the like against the outer-peripheral surface of a guide roller 911 and sliding the cleaning roller with respect to this outer-peripheral surface.
- a cleaning roller 914 such as that which has been formed using a foamable sponge or the like
- the cleaning roller 914 and the guide roller 911 are made to differ from each other whereby the guide roller 911 is slid at the surface of contact therebetween, scratching-away of the stains is performed more effectively.
- the cleaning roller is simultaneously replaced by the ink jet cartridge being replaced, the cleaning function is maintained to be performed almost permanently.
- a guide roller 1011 is incorporated in an ink jet cartridge 1001 and this guide roller 1011 is made rotatable about a rotating shaft 1114.
- This ink jet cartridge 1001 is removably mounted to a head carrier 1009 and this ink jet cartridge is structured such that when the ink therein has been used up, it is replaced by a new cartridge or is demounted once whereby ink is supplemented and then the resulting cartridge is mounted again.
- the gap distance can be maintained to be fixed without being influenced by the tolerance of mounting between the ink jet cartridge 1001 and the head carrier 1009, the variation in the gap distance can be suppressed to be smaller than in the above-mentioned case (First Embodiment).
- a guide roller 1111 for maintenance of the gap is not only incorporated but there maybe also incorporated a cleaning sponge 1115 as the cleaning means for cleaning the outer-peripheral surface of the guide roller 1111.
- Fig. 11(a) is a sectional view taken along a line A-A, illustration is made of a structure wherein the cleaning sponge 1111 is slid on the outer-peripheral surface of the guide roller 1111 to thereby wipe off the stains such as paper dust powder from this outer-peripheral surface.
- the ink jet recording apparatus has been structured such that on the ink jet cartridge or head carrier there is mounted the guide roller for regulating the gap distance between it and the printing medium whereby the guide roller is caused to run on the surface of the printing medium, the ink jet cartridge or head carrier follows the surface configuration of the printing surface while being in contact therewith, with the result that the gap distance between the jet surface of ink and the printing surface is maintained always to be fixed.
- the jetted state of ink becomes uniform over an entire region of printing, whereby the printed images become stable with the result that the thickness unevenness, positional displacement, color drift, etc. become difficult to occur. This effect is great particularly when electrically charging the ink droplets and accelerating them by the electrostatic force.
- the guide roller is located upstream in the feeding direction of paper and, when feeding the printing medium, the ink jet cartridge or head carrier having the guide roller mounted thereon is retracted to outside the printing medium, the printing medium can be conveyed without influencing the paper feeding precision. Since the ink jet recording apparatus is structured such that the guide roller is kept out of contact with the ink surface after printing, it is also possible to avoid the fear of staining the images.
- the rubber blades or sponge roller since in order to clean the outer-peripheral surface of the guide roller the rubber blades or sponge roller has been constructed integrally with the ink cartridge, it results that the stains or the like which cause the variation of the gap distance are always eliminated. Also, when the ink cartridge is replaced, the above-mentioned cleaning means are also replaced simultaneously, with the result that it does not happen that the cleaning performance deteriorates.
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- Ink Jet (AREA)
- Common Mechanisms (AREA)
Abstract
It is the object to convey a printing medium while ensuring a fixed gap distance
between an ink jet head and the printing medium even when the constituent parts are not
required to have a high machining precision and high assembling precision, and to
maintain this state as it is for a long period of time. On a main body of a ink jet
cartridge 101 or on a surface of a head carrier 109 for carrying the ink jet cartridge 101,
which is located upstream in the feeding direction of paper, there is mounted a guide
roller 111, whereby it is arranged that the guide roller 111 runs on the surface of a
printing medium 103. Also, it is arranged that blades , sponge roller or the like for
cleaning the outer-peripheral surface of the guide roller 111 is mounted on the ink jet
cartridge. Further, when feeding the printing medium, the ink jet cartridge has been
retracted to outside the printing medium.
Description
The present invention relates to an ink jet recording
apparatus that is equipped with an ink jet cartridge for jetting
a recording liquid onto a printing medium and thereby causing
it onto the printing medium to thereby perform recording and
a gap retaining mechanism for retaining the gap between the
ink jet cartridge and the printing medium, which gap retaining
mechanism is used in the ink jet recording apparatus.
An ink jet recording method is one which generates
droplets of ink and makes flight thereof and causes attachment
of a part or the whole thereof onto a printing medium such as
a sheet of paper to thereby perform recording, by the use of
various recording liquid jetting systems such as a system
wherein ink is attracted and jetted by electrostatic force,
a system wherein mechanical vibration or displacement is
imparted to recording liquid with the use of a piezoelectric
element, or a system wherein recording liquid is heated and
bubbled whereby the resulting pressure is utilized.
A paper conveying mechanism that is used in a
conventional ink jet recording mechanism will now be explained
with reference to the drawings. In Fig. 2, an ink jet cartridge
201 is disposed with a necessary gap (g) being kept between
itself and a platen 202. The platen 202 is made rotatable by
being made using a rubber roller or is formed using a highly
slidable resin into a somewhat curved convex configuration and
this platen is in a positional relation wherein a printing
medium 203 is in contact with the apex of the convex portion
of the platen. The printing medium 203 is conveyed up to a
printing zone that is composed of the ink jet cartridge 201
and the platen 202 by being clamped between a capstan 204 and
a pinch roller 205. At this time, in many cases, in order to
ensure the paper feeding precision, the capstan 204 is made
using a material of high rigidity such as stainless steel and
the pinch roller 205 is made using an elastic material such
as rubber.
Explaining briefly the operation of the ink jet
recording apparatus, as illustrated in Fig. 3, with a recording
apparatus 302 being composed of a power-supply unit 303 for
supplying a power to each element, an image processing circuit
304 for performing data conversion as the necessity arises with
respect to input image data, a controller 305 for performing
data transmission and data reception between the units and
controlling the operational sequence between the units, etc.,
the recording apparatus operates in such a way as to receive,
according to the instructions from the controller 305, the
image data input from an external device 301 such as a personal
computer, perform data conversion such as color conversion and
edge emphasis in the image processing circuit 304, and cause
ink to be jetted from an ink jet head unit 306 in correspondence
with the converted data to thereby cause an image to be formed
on the printing medium 307.
By the way, since the image that is formed is
generally two-dimensional and the ink jet openings of the ink
jet head unit 306 are disposed one-dimensionally, in order to
perform printing over a relevant entire region it becomes
necessary to use paper feeding means and ink jet head carrying
means (not illustrated) which are for the purpose of
sequentially feeding both of the head unit 306 and printing
medium 307 in directions perpendicular to each other to thereby
repeat the printing operation. In addition, when performing
the printing by moving the both elements, it is necessary to
maintain the gap distance between the ink jet head and the
printing medium to be at a fixed value. In the prior art, as
illustrated in Fig. 2, this end has hitherto been accomplished
by mounting a guide roller 211 onto a head carrier 209 having
mounted thereon an ink jet cartridge 201 and sliding the guide
roller 211 on a guide rail 208. It is to be noted that the guide
rail 208 is fixed to a frame member by being fastened thereto
by means of screws or the like.
However, in the conventional ink jet recording
apparatus having the above-mentioned construction, a certain
range of tolerance is needed to be provided for the degree of
parallelization between a sliding surface 212 of the guide rail
208 and a printing surface 213 and the flatness of the sliding
surface 212 itself of the guide rail 208, etc. Assuming that
the distances as measured from a base 211 to the sliding surface
212 and from the base 211 to the printing surface 213 be
represented by (a) and (b) respectively, since each of these
distances is not always a fixed value as illustrated in, for
example, Fig. 4, (l) which is the difference between (a) and
(b) is not a fixed value. Accordingly, it results that a gap
distance (g) has the same degree of variation as that of (l).
Actually, to the configuration tolerances of the above-mentioned
parts as single items of parts there are added
assembling tolerances such as the mounting tolerance of the
guide rail 208, with the result that the degree of variation
of the gap (g) becomes inconveniently a relatively large value
of, for example, 0. 1 to 0. 2 mm or so. Although in order to
make the variation degree of the gap distance lower it is
sufficient to enhance the machining precision and assembling
precision of the constituent parts such as the guide rail 208,
such enhancement has relevancy to the cost and therefore is
not advisable.
Also, as illustrated in Fig. 5, in a case of providing
an ink jet cartridge 501 and an opposing electrode 503 and
applying an electric field therebetween with the use of a d.c.
power source 502 to thereby fly an electrically charged ink
droplet 505, the force that acts on the ink droplet 505 is proportional to the field
intensity between the ink jet cartridge 501 and the opposing electrode 505. Accordingly,
the variation in the gap distance (g) is in direct correspondence with the variation in the
force that acts on the ink droplet 505, which results in the deterioration of the image
quality due to the variation in the printing conditions.
In a first aspect, there is provided an ink jet recording apparatus comprising ink
jetting means for jetting a recording liquid onto a printing medium in correspondence
with input image data, characterised by gap retaining means for maintaining a distance
between the printing medium and the ink jetting means to be at a predetermined value,
paper feeding means for for feeding the printing medium and head carrying means for
carrying the ink jetting means in a direction that is substantially perpendicular to feeding
direction of the printing medium.
In a second aspect, there is provided a gap retaining mechanism of an ink jet
recording apparatus comprising ink jetting means for jetting a recording liquid onto a
printing medium in correspondence with input image data, paper feeding means for
carrying the ink jetting means in a direction in which the printing medium is fed,
characterised by a roller member rotatably mounted on the ink jet means or head
carrying means and moveable in such a way as to rotate on the printing medium to
maintain a distance between the printing medium and the ink jetting means to be at a
fixed value.
On this account, in the present invention, there has been provided a mechanism
wherein a guide roller is mounted on an ink jet cartridge or head carrier for carrying the
ink jet cartridge and this guide roller is disposed such that its mounting position is
situated on a surface of the ink jet cartridge or head carrier which is upstream in the
paper feeding direction, whereby the guide roller runs on the surface of the printing
medium but not runs on the guide rail as in the prior art. By using this mechanism it
results that the ink jet cartridge follows, while being in contact with, the surface of the
printing medium, with the result that only if the dimensions are strictly determined with
regard to only the circularity of the guide roller and the eccentricity thereof at the time of
mounting thereof, even when the machining precision of the remaining constituent parts
is decreased, the variation degree of the gap distance can be maintained to be at an
appreciably small value. In addition, since the guide roller runs on the
printing surface on a side that is upstream in the paper feeding
direction, the guide roller does not touch the ink after
printing has been performed and therefore does not stain the
printed surface.
Also, there has been made a structure of mounting
onto a head carrier or ink cartridge cleaning means such as
blades and roller for cleaning the outer-peripheral surface
of the guide roller. By using this structure, since the
outer-peripheral surface of the guide roller is always kept
cleaned by the scratching action of the blade or sliding
movement of the roller, it does not happen that the variation
in the gap distance occurs with the lapse of time. Especially,
since when having mounted the cleaner with respect to the ink
cartridge the replacement of the ink cartridge being now used
results in simultaneous replacement of the cleaning means such
as the blades or roller, a fixed gap distance is maintained
almost permanently.
Fig. 1 is a side view illustrating an embodiment
wherein in an ink jet recording apparatus according to the
present invention a guide roller has been provided on a head
carrier.
Fig. 2 is a side view illustrating a printing portion
in particular of a conventional ink jet recording apparatus.
Fig. 3 is a block diagram illustrating the operation
of the ink jet recording apparatus.
Fig. 4 is a schematic diagram illustrating the
relationship of the distance between the sliding surface of
the guide rail and a base and the distance between the printing
surface and the base, with the head position as viewed in the
main scanning direction.
Fig. 5 is a schematic diagram illustrating the
operation that is performed when applying an electric field
to an electrically charged ink droplet.
Fig. 6 is an upper surface view illustrating the
operation of the ink jet recording apparatus according to the
present invention.
Fig. 7 is a schematic diagram illustrating that the
gap distance can be maintained to be fixed in the ink jet
recording apparatus according to the present invention.
Fig. 8 is a schematic diagram illustrating an
embodiment of cleaning means for cleaning the guide roller of
the ink jet recording apparatus according to the present
invention.
Fig. 9 is a schematic diagram illustrating another
embodiment of the cleaning means for cleaning the guide roller
of the ink jet recording apparatus according to the present
invention.
Fig. 10 is a side view illustrating an embodiment
wherein in the ink jet recording apparatus according to the
present invention the guide roller has been provided on the
ink jet cartridge. And,
Fig. 11 is a side view illustrating an embodiment
wherein in the ink jet recording apparatus according to the
present invention the guide roller and cleaning means have been
provided on the ink jet cartridge.
In the ink jet recording apparatus of the present
invention, there has been provided a mechanism wherein in order
to maintain the gap distance between the ink jet cartridge and
the printing medium the guide roller is provided to the ink
jet cartridge or head carrier and this guide roller is made
to run on the surface of the printing medium and, in addition,
this guide roller is disposed on a side that is upstream in
the printing direction. Further, means for cleaning the
outer-peripheral surface of the guide roller has been mounted
on the ink jet cartridge or head carrier.
An embodiment of the present invention will now be
explained by taking as an example a case of applying an electric
field to an electrically charged ink droplet and thereby
causing it to fly (a case such as that which is illustrated
in Fig. 5) . In Fig. 1, an ink jet cartridge 101 is structured
such that the ink jet cartridge 101 is removably mounted on
a head carrier 109, whereby when the ink has been used up, the
ink jet cartridge as a whole is replaced by a new cartridge
or otherwise is demounted once and, after ink is supplemented,
is mounted again. The head carrier 109 is arranged to be able
to make its reciprocating movements in directions
perpendicular to the paper surface and make its rocking
movements about a guide shaft. This reciprocating movement
is performed with a pulse motor (not illustrated) or the like
in order to be synchronized with transfer of data to the ink
jet cartridge 101. Also, since the center of gravity of the
entire head carrier is located on the left side of the guide
shaft 110, the moment acts on the entire head carrier due to
the gravitational force in the counterclockwise direction,
which results in that a guide roller 111 runs on the surface
of a printing medium 103 in such a way as to follow this surface
while being in contact therewith.
On a rear side of the printing medium 103 there is
provided an opposing electrode 113, which is formed to have
a size that can cover not only a region permitting it to oppose
the ink jet surface of the ink jet cartridge 101 but also a
region permitting it to oppose even a position at which it
opposes the guide roller 111.
Fig. 6 is an illustration wherein the printing
portion that is constructed in Fig. 1 has been viewed from above.
The right side of a printing medium 603 as viewed from the head
carrier 609 is in a state where print images are already formed.
The head carrier 609 is designed so that the home position
thereof is located at a point (E). The printing medium 603
is fed from a pinch roller 605 side and is conveyed in a direction
(C). Also, an ink jet cartridge 601 and the head carrier 609
are so arranged as to be able to make their reciprocating
movements in directions (A) and (B).
Actual printing operations are performed in units
of a single line, or simultaneously in units of several lines,
according to the number of ink jet openings of the ink jet head
601, while the head carrier 609 is moving in the direction of
(A). At this time, the printing medium 603 is in stoppage.
Upon completion of one line or several lines printing, the head
carrier is retracted once to the home position E, during which
the printing medium 603 is sequentially fed by a distance that
corresponds to the printed line or lines number in the direction
of (C). Thereafter, the head carrier 609 is returned in the
direction of (B) and then, while being moved in the direction
of (A), performs the next one line or several lines printing.
Here, since the rolling direction of the guide roller 611 (the
directions (A) and (B)) and the feeding direction of the
printing medium (the direction (C)) intersect each other at
right angles, unless when the printing medium 603 is fed the
head carrier 609 is retracted to the home position (E), the
conveying operation of the printing medium 603 ceases to be
performed smoothly, with the result that according to cases,
the paper feeding precision is inconveniently decreased.
Next, the reason why the gap distance is maintained
to be fixed will be explained. The illustration that is made
of Fig. 6 from the side of the pinch roller 605 is presented
in Fig. 7. Although the same thing has been stated also in
connection with the prior art, it is general that the
configuration of the opposing electrode 713 is not always
completely flat and has more or less an undulation or
inclination. As illustrated in, for example, Fig. 7, the
opposing electrode has an undulation of δ at maximum, and this
value is considered to be from approximately 0. 3 to 0. 6 mm
or so with respect to the printing of an A3 paper having a
printing width/short side of 210 mm. Since as explained in
connection with Fig. 1 the head carrier is given a clearance
that permits it to rotate about the guide shaft, if the vertical
variation of the head carrier is to an extent of from
approximately 0. 3 to 0. 6 mm or so, the head carrier 709 can
run on the surface of the printing medium 703 while being rocked
about the guide shaft 710 and following this surface
configuration thereof. Since the ink jet cartridge 701 is
mounted on the head carrier 709, the distance between the ink
jet surface of the head and the opposing electrode 713 is always
maintained to be fixed for the above-mentioned reasons.
Although in this embodiment illustration has been
made of the construction using a single roller as the gap
retaining means for maintaining the distance between the ink
jet cartridge constituting the ink jetting means and the
printing medium to be fixed, such gap retaining means can be
constructed by using even a plurality of roller members.
Meanwhile, since the gap roller such as the guide
roller for maintaining the gap is arranged to run on the surface
of the printing medium as mentioned above, there is supposed
also a case where as the number of printed sheets of paper
increases the outer-peripheral surface of the gap roller
becomes stained due to the paper dust powder. In such a case,
it is effective for the gap roller to have a cleaning mechanism
such as that which is illustrated in Fig. 8. In the ink jet
recording apparatus of Fig. 8, although almost all of the
constituent parts are the same as those which have been
hereinbefore stated, the ink jet recording apparatus of Fig.
8 differs from the preceding one in the respect of being
structured such that as illustrated in Fig. 8(b) an arm 812
is extended from an ink jet cartridge 801 and, as illustrated
in Fig. 8(a), a plate spring 814 and rubber blades 815 and 816
are mounted on a forward end of this arm 812. When the printing
is performed while the head carrier 809 is being moved in the
direction of (A), since the guide roller 811 is rotated in the
direction of (C), the stains that have attached onto the
outer-peripheral surface of the guide roller 811 are scratched
away by the rubber blades 815. Also, when one-time scanning
is completed whereby the head carrier 809 is moved in the
direction of (B) in order to return again to the position at
which the printing is started, the cleaning is performed by
the rubber blade 816 that is opposite to that which has been
mentioned above. In the case of this embodiment, when the ink
within the ink jet cartridge is used up and this ink jet
cartridge is replaced by a new ink jet cartridge, since the
cleaning blades are also replaced simultaneously, defective
cleaning is prevented due to the wear of the rubber blades.
Another embodiment of this cleaning mechanism is
illustrated in Figs. 9(a) and 9(b). This embodiment differs
from Fig. 8 in that scratching-away of the stains is performed
not by the rubber blades but by pressing a cleaning roller 914
such as that which has been formed using a foamable sponge or
the like against the outer-peripheral surface of a guide roller
911 and sliding the cleaning roller with respect to this
outer-peripheral surface. Especially, if the peripheral
velocities of the cleaning roller 914 and the guide roller 911
are made to differ from each other whereby the guide roller
911 is slid at the surface of contact therebetween,
scratching-away of the stains is performed more effectively.
In this case, also, since the cleaning roller is simultaneously
replaced by the ink jet cartridge being replaced, the cleaning
function is maintained to be performed almost permanently.
It is to be noted that in this embodiment there has
been shown the cleaning system that uses the rubber blades or
cleaning roller, the invention is not limited thereto and
permits other cleaning systems to be of course used with the
same effect being brought about.
A case where the gap retaining means is contained
in the ink jet cartridge will now be explained by way of example
as a second embodiment of the present invention with reference
to the drawings. As illustrated in Fig. 10, a guide roller 1011
is incorporated in an ink jet cartridge 1001 and this guide
roller 1011 is made rotatable about a rotating shaft 1114. This
ink jet cartridge 1001 is removably mounted to a head carrier
1009 and this ink jet cartridge is structured such that when
the ink therein has been used up, it is replaced by a new
cartridge or is demounted once whereby ink is supplemented and
then the resulting cartridge is mounted again. In the case
of the structure illustrated in this embodiment by way of
example, since the gap distance can be maintained to be fixed
without being influenced by the tolerance of mounting between
the ink jet cartridge 1001 and the head carrier 1009, the
variation in the gap distance can be suppressed to be smaller
than in the above-mentioned case (First Embodiment).
Also, as illustrated in Fig. 11, a guide roller 1111
for maintenance of the gap is not only incorporated but there
maybe also incorporated a cleaning sponge 1115 as the cleaning
means for cleaning the outer-peripheral surface of the guide
roller 1111. While Fig. 11(a) is a sectional view taken along
a line A-A, illustration is made of a structure wherein the
cleaning sponge 1111 is slid on the outer-peripheral surface
of the guide roller 1111 to thereby wipe off the stains such
as paper dust powder from this outer-peripheral surface.
Incidentally, since the operation, the reason why
the gap distance is maintained to be fixed, etc. have been
explained in the preceding embodiment, their re-explanation
is omitted.
Although in this embodiment illustration has been
made of the cleaning system that uses the cleaning sponge, the
invention is not limited thereto and permits even other
cleaning systems to be also used such as the cleaning systems
illustrated in the preceding embodiment.
The present invention is worked out in the
above-mentioned forms of embodiments and brings about the
effects that are described as follows.
Since the ink jet recording apparatus has been
structured such that on the ink jet cartridge or head carrier
there is mounted the guide roller for regulating the gap
distance between it and the printing medium whereby the guide
roller is caused to run on the surface of the printing medium,
the ink jet cartridge or head carrier follows the surface
configuration of the printing surface while being in contact
therewith, with the result that the gap distance between the
jet surface of ink and the printing surface is maintained always
to be fixed. In consequence, the jetted state of ink becomes
uniform over an entire region of printing, whereby the printed
images become stable with the result that the thickness
unevenness, positional displacement, color drift, etc. become
difficult to occur. This effect is great particularly when
electrically charging the ink droplets and accelerating them
by the electrostatic force.
Also, since the guide roller is located upstream in
the feeding direction of paper and, when feeding the printing
medium, the ink jet cartridge or head carrier having the guide
roller mounted thereon is retracted to outside the printing
medium, the printing medium can be conveyed without influencing
the paper feeding precision. Since the ink jet recording
apparatus is structured such that the guide roller is kept out
of contact with the ink surface after printing, it is also
possible to avoid the fear of staining the images.
Further, since in order to clean the outer-peripheral
surface of the guide roller the rubber blades or
sponge roller has been constructed integrally with the ink
cartridge, it results that the stains or the like which cause
the variation of the gap distance are always eliminated. Also,
when the ink cartridge is replaced, the above-mentioned
cleaning means are also replaced simultaneously, with the
result that it does not happen that the cleaning performance deteriorates.
In addition, since if the clearances are made somewhat severe with respect to only
the machining precision of the guide roller and the mounting thereof a desired value of
gap distance can be ensured even when the tolerance is eased with respect to the
remaining constituent parts and assembling thereof, there can be decreased the parts cost
and assembling cost as viewed from the apparatus as a whole.
Claims (8)
- An ink jet recording apparatus comprising ink jetting means (101, 801, 901, 1001) for jetting a recording liquid onto a printing medium (103, 803, 903, 1003) in correspondence with input image data, characterised by gap retaining means (111, 811, 911, 1011) for maintaining a distance between the printing medium and the ink jetting means to be at a predetermined value, paper feeding means for (104, 105, 107; 1004, 1005) for feeding the printing medium and head carrying means (109, 809, 909, 1009) for carrying the ink jetting means in a direction that is substantially perpendicular to feeding direction of the printing medium.
- An ink jet recording apparatus as set forth in claim 1, wherein the gap retaining means has a construction of having one or a plurality of roller members and being mounted to a surface of the ink jetting means or head carrying means which is situated upstream in the paper feeding direction.
- An ink jet recording apparatus as set forth in claim 2, wherein the roller member of the gap retaining means is arranged for running on a printing surface of the printing medium.
- An ink jet recording apparatus as set forth in claim 2 or 3, wherein the roller member is mounted (114) on the ink jetting means.
- An ink jet recording apparatus as set forth in claim 2 or 3, wherein the roller member is mounted (114) on the head carrying means.
- An ink jet recording apparatus as set forth in any of claims 2 to 5, wherein the gap retaining means includes cleaning means (814-816; 914) for cleaning an outer-peripheral surface of the roller member.
- An ink jet recording apparatus as set forth in any of claims 1 to 6, wherein the head carrying means causes the ink jetting means to be retracted to outside the printing medium (E) when the printing medium is fed.
- A gap retaining mechanism of an ink jet recording apparatus comprising ink jetting means (101, 801, 901, 1001) for jetting a recording liquid onto a printing medium in correspondence with input image data, paper feeding means (104-107; 1004, 1005) for feeding the printing medium and head carrying means (109, 809, 909, 1009) for carrying the ink jetting means in a direction that is substantially perpendicular to a direction in which the printing medium is fed, characterised by a roller member (111, 811, 911, 1011) rotatably mounted on the jetting means or head carrying means and moveable in such a way as to rotate on the printing medium to maintain a distance between the printing medium and the ink jetting means to be at a fixed value.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16634596A JPH106491A (en) | 1996-06-26 | 1996-06-26 | Ink jet recorder and head gap holding mechanism used therefor |
JP166345/96 | 1996-06-26 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0816109A1 true EP0816109A1 (en) | 1998-01-07 |
Family
ID=15829663
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97304272A Withdrawn EP0816109A1 (en) | 1996-06-26 | 1997-06-18 | Ink jet recording apparatus and head gap retaining mechanism for use therein |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0816109A1 (en) |
JP (1) | JPH106491A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2881374A1 (en) * | 2005-01-31 | 2006-08-04 | Neopost Ind Sa | Franking machine for use in courier processing field, has printing head that is moved along direction perpendicular to courier transportation path by lifting end of driving arm when rolled at end contacts printing surface of courier article |
WO2014003719A1 (en) * | 2012-06-26 | 2014-01-03 | Hewlett-Packard Development Company, L.P. | Media guide |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006297852A (en) | 2005-04-25 | 2006-11-02 | Funai Electric Co Ltd | Cleaning member for printing head section |
JP5321437B2 (en) * | 2009-12-14 | 2013-10-23 | 沖電気工業株式会社 | Impact printer |
JP5434878B2 (en) * | 2010-10-04 | 2014-03-05 | ブラザー工業株式会社 | Ink jet recording apparatus and method for cleaning protective member provided on the same |
JP5842450B2 (en) * | 2011-08-08 | 2016-01-13 | ブラザー工業株式会社 | Inkjet recording device |
JP7059532B2 (en) * | 2017-07-26 | 2022-04-26 | セイコーエプソン株式会社 | Liquid discharge device |
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DE2902037A1 (en) * | 1979-01-19 | 1980-07-24 | Olympia Werke Ag | Ink jet printing head of laminated construction - has lugs on outer laminates to provide retention for contact ball roller |
US5065169A (en) * | 1988-03-21 | 1991-11-12 | Hewlett-Packard Company | Device to assure paper flatness and pen-to-paper spacing during printing |
JPH0439076A (en) * | 1990-06-05 | 1992-02-10 | Seiko Epson Corp | Ink jet printer |
JPH0444853A (en) * | 1990-06-12 | 1992-02-14 | Canon Inc | Ink jet recording apparatus |
JPH04247975A (en) * | 1991-01-25 | 1992-09-03 | Tokyo Electric Co Ltd | Head gap adjustment device |
EP0529606A2 (en) * | 1991-08-27 | 1993-03-03 | Canon Kabushiki Kaisha | Recording apparatus |
-
1996
- 1996-06-26 JP JP16634596A patent/JPH106491A/en active Pending
-
1997
- 1997-06-18 EP EP97304272A patent/EP0816109A1/en not_active Withdrawn
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2902037A1 (en) * | 1979-01-19 | 1980-07-24 | Olympia Werke Ag | Ink jet printing head of laminated construction - has lugs on outer laminates to provide retention for contact ball roller |
US5065169A (en) * | 1988-03-21 | 1991-11-12 | Hewlett-Packard Company | Device to assure paper flatness and pen-to-paper spacing during printing |
JPH0439076A (en) * | 1990-06-05 | 1992-02-10 | Seiko Epson Corp | Ink jet printer |
JPH0444853A (en) * | 1990-06-12 | 1992-02-14 | Canon Inc | Ink jet recording apparatus |
JPH04247975A (en) * | 1991-01-25 | 1992-09-03 | Tokyo Electric Co Ltd | Head gap adjustment device |
EP0529606A2 (en) * | 1991-08-27 | 1993-03-03 | Canon Kabushiki Kaisha | Recording apparatus |
Non-Patent Citations (3)
Title |
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PATENT ABSTRACTS OF JAPAN vol. 016, no. 214 (M - 1251) 20 May 1992 (1992-05-20) * |
PATENT ABSTRACTS OF JAPAN vol. 016, no. 226 (M - 1254) 26 May 1992 (1992-05-26) * |
PATENT ABSTRACTS OF JAPAN vol. 017, no. 021 (M - 1353) 14 January 1993 (1993-01-14) * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2881374A1 (en) * | 2005-01-31 | 2006-08-04 | Neopost Ind Sa | Franking machine for use in courier processing field, has printing head that is moved along direction perpendicular to courier transportation path by lifting end of driving arm when rolled at end contacts printing surface of courier article |
WO2014003719A1 (en) * | 2012-06-26 | 2014-01-03 | Hewlett-Packard Development Company, L.P. | Media guide |
GB2517849A (en) * | 2012-06-26 | 2015-03-04 | Hewlett Packard Development Co | Media guide |
US9162488B2 (en) | 2012-06-26 | 2015-10-20 | Hewlett-Packard Development Company, L.P. | Media guide |
GB2517849B (en) * | 2012-06-26 | 2020-03-25 | Hewlett Packard Development Co | Media guide |
Also Published As
Publication number | Publication date |
---|---|
JPH106491A (en) | 1998-01-13 |
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