JP2002337354A - Ink jet recording unit and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ink from leaking from nozzle holes of an ink jet head when an ink jet recording unit having the ink jet head and an ink holding part integrated is carried or the like. SOLUTION: The ink jet recording unit 10 has at least the ink jet head 11 for discharging ink from nozzle holes 14, thereby printing to a recording medium 4 such as a recording paper; and the ink holding part 13 for holding ink to be supplied to the ink jet head. The nozzle holes are arranged in a longitudinal direction of the ink jet head. When the ink jet head stands vertically to a horizontal face while the longitudinal direction of the ink jet head is made an up-down direction, the ink jet head and the ink holding part are connected to each other so that a head pressure of the nozzle hole 14y at a most leading part in the longitudinal direction of the ink jet head and close to the horizontal face becomes negative.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel ink jet recording unit and a new printer. In detail, an ink jet head that ejects ink from nozzle holes to print on a recording medium such as recording paper, and an ink holding unit that holds ink to be supplied to the ink jet head are integrally combined and exchanged for a printer. The present invention relates to a technology for preventing ink from leaking from nozzle holes, and relates to an ink jet recording unit configured to be capable of and a printer using the ink jet recording unit.

[0002]

2. Description of the Related Art A method of performing printing or drawing, that is, printing by discharging fine ink droplets toward a recording medium such as recording paper or cloth, that is, an ink jet printer (hereinafter, referred to as an "ink jet printer"). ).

An ink jet printer includes a nozzle hole for discharging ink, pressure chambers provided corresponding to each nozzle hole, a discharge means provided for each pressure chamber, and an ink flow path for supplying ink to each pressure chamber. And an ink holding unit for supplying ink to the ink jet head. In a conventional ink jet printer, the ink holding unit is a cartridge (ink cartridge) detachable from the ink jet head. ) Format, and when the ink is used up,
The ink cartridge had to be replaced.

[0004]

By the way, when an ink jet head and an ink holding unit are integrated into a cartridge as an ink jet recording unit, the ink jet recording unit can be inserted into and removed from the printer, and the ink jet recording unit can be detached from the printer and carried. The following problems occur.

That is, when the ink jet recording unit is detached from the printer, such as when carrying the cartridge, there is a problem that the ink leaks from the nozzle holes of the ink jet head.

[0006] In addition, when the ink jet recording unit moves while being attached to the printer, or when it receives an impact due to an earthquake or the like, ink may leak from the nozzle holes.

[0007] The above problems become remarkable in an ink jet recording unit for a line printer described later.

On the other hand, an ink jet recording unit for performing color printing requires inks of a plurality of colors, for example, four colors of cyan, magenta, yellow, and black. Of course, these four colors of ink leak out. We need to make sure they don't get stuck.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording unit having an ink jet head and an ink holding unit integrated so as to prevent ink from leaking from nozzle holes of the ink jet head when being carried. I do.

[0010]

In order to solve the above-mentioned problems, the ink jet recording unit according to the present invention is characterized in that when the ink jet head is set up vertically with respect to a horizontal plane with the longitudinal direction of the ink jet head up and down. The inkjet head and the ink holding unit are connected such that the head pressure of the nozzle hole near the horizontal plane at the end of the inkjet head in the longitudinal direction becomes negative.

Therefore, in the ink jet head of the present invention, the head pressure caused by the ink applied to the nozzle hole near the horizontal plane at the extreme end in the longitudinal direction of the ink jet head is negative pressure regardless of the posture. Thus, leakage of the ink can be prevented.

Further, in order to solve the above-described problems, the printer of the present invention is arranged such that when the ink-jet head is set upright with respect to a horizontal plane with the longitudinal direction of the ink-jet head up and down, The ink jet recording unit connecting the ink jet head and the ink holding unit is detachably mounted so that the head pressure of the nozzle hole at the end and near the horizontal plane becomes a negative pressure.

Therefore, in the printer of the present invention, the head pressure due to the ink applied to the nozzle hole near the horizontal plane at the extreme end in the longitudinal direction of the ink jet head becomes negative regardless of the posture of the ink jet head. In addition, leakage of ink can be prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of an ink jet recording unit and a printer according to the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 schematically show an example of a printer to which an ink jet recording unit according to the present invention is mounted.

The printer 1 is a line printer that prints the recording paper in the horizontal direction at a time. A cartridge frame 3 is fixedly provided substantially at the center of the printer body 2 so as to cross the recording paper conveyance direction (see the arrow A in the figure).

The recording paper 4 is stored in a state where a large number of recording papers 4 are stacked on a paper tray 5 which is detachably attached to one end of the printer main body 2. 2 is attached. And recording paper 4
Is transported in the direction of arrow A in the figure by recording paper transporting means (not shown), and is discharged by a paper discharge roller 6 to a paper discharge receiving unit (not shown).

The ink jet head 7 and the ink holding portion (ink tank) 8 are connected at a connection position which is a feature of the present invention, which will be described later, and are integrated into a cartridge as an ink jet recording unit 9 (see FIG. 1). ). The ink jet recording unit 7 is configured to be detachable from the printer 1. Then, the ink jet recording unit 9 is mounted on the cartridge frame 3 of the printer 1 and the preparation for printing is completed (see FIG. 2).

When printing is started, the recording paper 4 is conveyed in the direction of arrow A as described above, and is ejected by the ink jet recording unit 9 mounted on the printer main body 2 until the recording paper 4 is discharged to the paper discharge receiving section. The head 7 passes under the portion where the nozzle hole is located, and at the time of the passing, printing is performed in the entire lateral direction, that is, over the entire width.

FIGS. 3 and 4 conceptually show the ink jet recording head of the present invention.

The ink jet recording unit 10 is formed by integrally connecting an ink jet head 11 and an ink tank 12. The ink tank 12 is formed by integrally forming four ink holding units 13B, 13C, 13M, and 13Y, and each ink holding unit 13 stores ink of a different color. That is, black ink is stored in the ink holding unit 13B, cyan ink is stored in the ink holding unit 13C, magenta ink is stored in the ink holding unit 13M, and yellow ink is stored in the ink holding unit 13Y.

Four ink jet heads are integrally formed corresponding to the four color inks.
1 shows an example in which three inkjet heads are integrated.

The ink-jet head 11 has a head chip formed with a concave portion serving as an ink flow path and a pressure chamber on a semiconductor chip and provided with a discharge means in the pressure chamber, and nozzle holes 14, 14,... A plurality of pressure chambers and discharge means corresponding to each of the pressure chambers are formed on one head chip. There can be various discharge means, and for example, an electro-thermal conversion element such as a heater or an electro-mechanical conversion element such as a piezo element can be applied.

Each of the ink holding portions 13 is in the form of a closed container, and has an ink storage chamber 15 and a porous material filling chamber 16. These two chambers 15 and 16 are provided with communication holes 1 provided at the lower end.
7 (see FIG. 4). The ink storage chamber 15 is provided with an ink filling hole for filling ink and a valve for opening and closing the ink filling hole, but is not shown.

The porous material filling chamber 16 is provided at the upper end of the air communication hole 1.
8 communicates with the outside. This atmosphere communication hole 18
Thereby, the porous material filling chamber 16 receives the back pressure of the atmospheric pressure. A filter 19 is provided in the atmosphere communication hole 18 so that dust and the like do not enter the porous material filling chamber 16 from outside (see FIG. 4). Although not shown, it is desirable that the air communication hole 18 be closed by a suitable sealing member when not in use or when not in use.

The porous material filling chamber 16 is filled with an appropriate porous material 20 such as a sponge as an ink absorber (see FIG. 4). The porous material 20 sucks and holds the ink in the ink storage chamber 15 by its capillary force. Further, an appropriate negative pressure is generated on the inkjet head 11 side. Therefore, the ink is not supplied to the inkjet head 11 more than necessary.

The porous material filling chamber 16 of the ink holding section 13 and the ink flow path of the ink jet head 11 are connected by an ink supply path (ink supply section) 21. The ink supplied from 13 is filled in each pressure chamber through the ink flow path.

When electric energy is supplied to the ejection means in accordance with the ejection signal from the printer body,
The ejection means generates a rapid pressure change (due to the generation of bubbles in the ink due to the rapid heat generation of the ejection means, the rapid deformation of the ejection means, etc.), and using this as ejection energy, the nozzle holes 14, 14,. The ink is ejected from the predetermined one. After the ejection, the ink flows into the nozzle holes 14, 14,.
···························································································································································································· 次 ·

In the present invention, when the water head pressure applied to the nozzle hole 14 at the end of the ink jet head 11 in the longitudinal direction is set up vertically so that the longitudinal direction of the ink jet head 11 is A connection position between the ink jet head 11 and the ink holding unit 13 is provided at a position.

In this embodiment, in the ink jet recording unit 10, the longitudinal direction of the ink jet head 11 (the direction indicated by arrow B in FIG. 4).
Is connected to the ink holding unit 13 at the center of the. That is, the ink supply path (ink supply section) 21 is provided at the center of the inkjet head 11 in the longitudinal direction.

The meaning of providing the ink supply path 21 at the center in the longitudinal direction of the ink jet head 11 as described above will be described with reference to FIGS.

First, in FIG. 5, when the ink head jet head 11 is set up vertically, if the negative pressure on the ink holding unit 13 side is assumed to be 0, a portion above the connection position with the ink holding unit 13 is assumed. In this case, a negative pressure is applied to the nozzle hole 14a, and the head pressure applied to the nozzle hole 14b at the connection position becomes zero. A positive pressure is applied to the nozzle hole 14c below the connection position, and the head pressure applied to the nozzle hole 14c located at the lowermost end (L1 (mm) below the connection position) is L1 (mmH ₂ O). Become. The head pressure applied to the nozzle hole 14d located below the connection position and above L2 (mm) from the lowermost end is (L
A 1-L2) mmH ₂ O.

Here, the nozzle hole 14 can withstand a negative pressure, that is, a force sucked from the inside, up to several KPa (kilopascal) by a capillary force. The state filled with ink is not broken. On the other hand, the nozzle hole 14
Can hardly resist the positive pressure, that is, the force for pushing out. That is, below the nozzle hole 14b at the connection position,
Since there is a negative pressure Pp (mmH ₂ O) (primarily due to the capillary force of the porous material 16) generated in the ink holding unit 13, the water head pressure PN applied to the nozzle holes 14c and 14d
Is PN = L1−L2 + Pp (each unit is mmH ₂ O)
And when PN> 0, the corresponding nozzle holes 14c and 14d
Will leak from the ink.

Therefore, if the ink jet head 11 is a line head that prints at a time in the horizontal direction on A4 size recording paper, the distance from the nozzle hole 14x at one end to the nozzle hole 14y at the other end is considered. Is 220 mm. Therefore, if it is assumed that the ink jet head 11 is connected to the ink holding portion 13 at a portion other than the center in the longitudinal direction, the nozzle hole at one end, for example, from the connection position with the ink holding portion 13 at 14y. The distance becomes 110 mm or more. Therefore, when the ink jet head 11 is placed in a vertical position with the nozzle hole 14y facing downward, the head pressure applied to the nozzle hole 14y is 110 mm.
H ₂ O or more. This means that if the absolute value of the negative pressure Pp generated in the ink holding unit 13 is smaller than 110 mmH ₂ O, the nozzle hole 1
4y leaks ink.

On the other hand, as in the ink jet recording unit 10 according to the present invention shown in FIG. 6, if the ink jet head 11 is connected to the ink holding portion 13 at the center in the longitudinal direction, the ink jet recording is performed with either end down. Even when the unit 10 is in the vertical position, the head pressure applied to the nozzle hole 14x or 14y located at the lowermost end is 11
Since at 0 mm H ₂ O, the absolute value of the negative pressure Pp occurring in the ink holding portion 13 is equal greater than 110mmH ₂ O, never leak out the ink.

Here, the negative pressure in the ink holding unit 13 is increased, and the ink jet head 11 and the ink holding unit 1 are increased.
The position of connection with the nozzle hole 3a may be shifted from the center to the end as shown in FIG. 5, but as described above, the negative pressure at the nozzle hole 14a in FIG. There is a possibility that bubbles will flow in from 14a. Further, such a phenomenon becomes more conspicuous as the length of the ink jet head 11 in the longitudinal direction is longer. In the above example, the A4 size is described as an example, but it is more severe when applied to the A3 size. Needless to say. That is, the present invention can obtain a greater effect when the long inkjet head 11 is used.

In the above-described embodiment, the connection position between the ink jet head 11 and the ink holding unit 13 has been described as the center in the longitudinal direction of the ink jet head 11, but as will be understood from the gist of the present invention, It is not limited to this. In other words, the connection position may be provided at the end of the inkjet head 11 in the longitudinal direction and at a position where the head pressure of the nozzle hole (14y in FIG. 5) close to the horizontal plane becomes negative.

Next, the arrangement of the ink holding unit 13 in the ink tank 12 will be considered with reference to FIGS.

The ink jet recording unit 1 shown in FIG.
At 0A, the ink tank 12A moves the four ink holding portions 13B, 13M, 13C, and 13Y in the direction (indicated by arrow Y in FIG. 7) orthogonal to the longitudinal direction of the inkjet head 11 (indicated by arrow X in FIG. 7). It consists of side by side,
In each of the ink holding portions 13B, 13M, 13C, and 13Y, a porous material filling chamber 16, 16,... Is disposed at the center, and one of the porous material filling chambers 16, 16,. , And empty chambers (empty chambers not filled with ink) 22, 2 on the other side.
2,... Are arranged.

With the above-described structure of the ink tank 12A, the ink supply section (connection section to the ink jet head 11) communicating with the porous material filling chambers 16, 16,. Arrow X
(See FIG. 2) can be arranged side by side in the direction perpendicular to the longitudinal direction.

However, in the ink jet recording unit 10A shown in FIG.
.. Are located on one side in the longitudinal direction of the inkjet head 11, so that the center of gravity of the inkjet recording unit 10A is
.. Are shifted to the side where they are located, resulting in a problem that the overall balance is deteriorated. And
If the balance of the entire ink jet recording unit 10A is poor, a portion supporting the ink jet head recording unit 10A of the printer (see the cartridge frame 3 in FIG. 1).
However, there are many inconveniences, such as the necessity of an asymmetrical structure (meaning both ends in the longitudinal direction of the ink jet head 11), and inconvenience in carrying.

FIG. 8 shows an example in which the arrangement is balanced in the right and left directions in consideration of the above-described circumstances.

The ink jet recording unit 10B shown in FIG. 8 has four ink holding portions 13B, 13M, 13
C and 13Y are arranged side by side in the direction (indicated by arrow Y in FIG. 8) orthogonal to the longitudinal direction of the ink jet head 11 (indicated by arrow X in FIG. 8), and the ink holding portions 13B, 13M,
In 13C and 13Y, the porous material filling chamber 1 is provided at the center.
, 16 are arranged in the ink tank 12A of the ink jet recording unit 10A shown in FIG.
Is the same as However, in the ink tank 12B, each of the ink holding units 13B, 13M, 13C, 13C
, And the porous material filling chambers 16, 16,... Are alternately provided in Y, that is, the ink holding portions 13 are provided on one side in the longitudinal direction (see the arrow X).
B ink storage chamber 15 and empty chamber 2 of ink holding unit 13C
2. The ink storage chamber 15 of the ink holding section 13M and the empty chamber 22 of the ink holding section 13Y are arranged in this order in the orthogonal direction (see arrow Y), and the ink holding section 13B is arranged on the other side in the longitudinal direction (see arrow X). Empty space 22, ink holding unit 1
3C ink chamber 15, empty chamber 2 of ink holding unit 13M
2. The ink storage chambers 15 of the ink holding section 13Y are arranged in the orthogonal direction (see arrow Y) in this order.

Therefore, in the ink tank 12B, the ink storage chambers 15 filled with ink are provided.
Are arranged separately on the left and right (refer to both ends in the longitudinal direction of the ink jet head 11) about the porous material filling chambers 16, 16,. The inconvenience caused by the left and right imbalance is eliminated.

Incidentally, The configuration shown in FIG. 8 is merely an example of a configuration for achieving a right-left balance, and the point is that any configuration may be used as long as the portion to be filled with ink is not unevenly distributed on either the left or right.

FIGS. 9 to 15 show an embodiment of the ink jet recording unit of the present invention.

The ink jet recording unit 100 has an ink tank 110 and an ink jet head 120 integrally connected via a frame 130. In addition, the inkjet recording unit 100 requires members such as a flexible printed circuit board provided with an electrode and a conductor for supplying electric energy to the ejection means in addition to the above-described members. And description is omitted.

The ink jet recording unit 100 according to the illustrated embodiment is applied to a full-color line printer.

FIGS. 11 and 12 show the housing 111 of the ink tank 110. FIG.

The housing 111 has an outer peripheral wall 111 a and a partition wall 1.
11b, 111b,..., Four ink storage chambers 112B, 112M, 112C, 112Y
And four porous material filling chambers 113B, 113M, 1
13C and 113Y are formed. Each of the ink storage chambers 112 and the porous material charging chambers 113 has 112B and 113B, 112M and 113M, and 112C and 1C.
13C, 112Y and 113Y are respectively communicated with each other by communication holes 114, 114,. Each of the ink storage chambers 112B, 112M, 11
2C, 112Y and porous material filling chambers 113B, 113M,
The ink holding units 115B, 115M, 115C, and 115 correspond to each other corresponding to 113C and 113Y.
Y is configured. And each porous material filling chamber 113B,
Are formed at the bottoms of 113M, 113C and 113Y.

The ink supply section 116 includes a fitting recess 116a opened on the lower surface and an ink supply path 117 communicating between the fitting recess 116a and the porous material filling chamber 113. A cylindrical bushing 117a made of an elastic material is provided in an inner fitting manner. Are formed side by side in the width direction at the center in the longitudinal direction of the ink tank 110 (see FIGS. 11 and 12). Further, the ink storage chambers 112B, 112M, 112C, 112Y of the respective ink holding units 115B, 115M, 115C, 115Y.
Means that 112B and 112Y are porous material filling chambers 113B,
13Y is disposed on one side in the longitudinal direction across the 13Y,
112M and 112C are porous material filling chambers 113M and 113M.
It is arranged on the other side in the longitudinal direction with 3C interposed therebetween, and is designed so that when ink is filled, the center of gravity of the ink tank 110 is near the center in the longitudinal direction.

The porous material filling chambers 113B, 113M, 113C and 113Y of the ink tank 110 are filled with a porous material (not shown), and the upper surface of the housing 111 is closed by a cover (not shown). The ink storage chambers 112B, 112M, 112C, 1
An ink filling hole is formed corresponding to 12Y, and an air communication hole is formed corresponding to each of the porous material filling chambers 113B, 113M, 113C, and 113Y. Then, black ink is stored in the ink storage chamber 112B and the porous material filling chamber 113B.
M is filled with magenta ink, ink storage chamber 112C and porous material filling chamber 113C are filled with cyan ink, and ink storage chamber 112Y and porous material filling chamber 113Y are filled with yellow ink.

The ink jet head 120 has a nozzle sheet 121 and a number of head chips 122, 122,.
, And channel plates 123, 123,... (FIG. 10,
See FIG. 13).

The nozzle sheet 121 has a large number of nozzle holes 1 formed in a metal sheet by electroforming a metal such as nickel.
21a, 121a,... (See the drawing circle in FIG. 13).

The head chip 122 includes the semiconductor chip 12
2a are formed as pressure chambers 122b, 122b,... And discharge means 122c, 122c,.
And each pressure chamber is a nozzle sheet 1
The nozzle holes 121a, 121a,.
Are attached to the nozzle sheet 121 so as to correspond one-to-one to the nozzle sheet 121.

Although only one channel plate 123 is shown in the drawing, four channel plates 123 corresponding to the four color inks are provided.
123 are used. These flow path plates 123, 1
23 are the head chips 122, 122,...
・ Head chips 122, 12
, And the ink flow paths 124, 124,... The flow path plate 1
23, 123,..., Ink receiving units 125, 125,
Are formed, and the ink receiving portions 125 and 12 are formed.
5, ... are fitting recesses 125a, 12 opened upward.
5a,... And the fitting recesses 125a, 125a,.
Are formed (see FIG. 13). The ink receiving paths 126, 126,...

The ink supply unit 1 of the ink tank 110
, And the ink receiving units 125, 125,... Of the inkjet head 120 are separately connected via ink supply path connection units 140, 140,. reference).

The ink supply path connection unit 140 has a substantially columnar overall shape. A fitting groove 141 extending over the entire circumference is formed on an outer peripheral surface of a substantially intermediate portion in the axial direction of the ink supply path connection unit 140, and a press-fitting portion 142 having a smaller outer diameter than the other portion protrudes at one end. The other end is provided with a connecting portion 143 having a smaller outer diameter than the other portions. The tip 142 of the press-fit portion 142
a is formed in a tapered shape. The ink supply path connection unit 140 has a unit flow path 144 formed through the center thereof.

First, the ink supply path connection unit 140,
Are fitted into the fitting grooves 141, 141,... Such as O-rings (see FIGS. 9 and 10).

Then, the ink supply path connection unit 1
40, 140,...
The lower part from 41,...
Are fitted and fixed to fitting recesses 125a, 125a,... Of the 20 ink receiving portions 125, 125,. Then, the ink supply path connection units 140, 140,...
Are fitted in the ink receiving paths 126, 126,... Of the ink jet head 120, and as a result, the unit flow paths 144, 144,. , ... are connected.

As described above, the ink jet head 120 to which the ink supply path connection units 140, 140,... Are attached is fixed to the lower surface of the frame 130 (FIG. 9).
), Ink supply path connection units 140, 140,.
.. through holes 131, 13 formed in the bottom surface of the frame 130 with portions above fitting grooves 141, 141,.
Project upward from 1, ... (see FIG. 17).

Then, the ink supply path connection unit 14
The ink supply unit 116 of the ink tank 110, which includes fitting grooves 141, 141,... Of 0, 140,. 116, fitting recesses 116a, 11
6a,... At this time, the press-fitting portions 142, 142,.
, 117,...
, 117a,. Therefore, the press-fit portion 1
42, 142,... Are bushings 117a, 117
a,... via the ink supply paths 117, 117,.
・ It is in close contact with the inner peripheral surface of the sealing member 145, 145,
Are pressed against the inner peripheral surfaces of the fitting concave portions 116a, 116a,..., And the outer peripheral surfaces of the ink supply path connecting units 140, 140,. The space is tightly sealed (see FIG. 9).

In the above embodiments and examples, the present invention is applied to an ink jet recording unit used for a line printer. However, the present invention is applied to an ink jet recording unit for a line printer. The present invention is not limited to this, and it goes without saying that the present invention can be applied to other types of printers, for example, an ink jet recording unit used in a serial printer.

Further, the shapes and structures of the respective parts shown in the above-described embodiments and examples are merely examples of the embodiment to be carried out when carrying out the present invention. The technical scope should not be interpreted in a limited manner.

[0065]

As is apparent from the above description, the ink jet recording unit of the present invention comprises: an ink jet head for discharging ink from at least nozzle holes to print on a recording medium such as recording paper; And an ink holding portion for holding ink for performing the operation, the nozzle holes are arranged in the longitudinal direction of the inkjet head, the inkjet head is set up and down, and the inkjet head is set upright with respect to a horizontal plane. At the end of the longitudinal direction of the inkjet head, and the inkjet head and the ink holding unit are connected such that the head pressure of the nozzle hole near the horizontal plane is negative. I do.

Therefore, in the ink jet recording unit of the present invention, the head pressure of the ink applied to the nozzle hole at the end portion in the longitudinal direction of the ink jet head and near the horizontal plane is negative regardless of the posture. Pressure, which can prevent ink from leaking.

According to the second aspect of the present invention, since the ink jet head and the ink holding portion are connected at the central portion in the longitudinal direction of the ink jet head, the ink jet head can be mounted in any posture. The head pressure due to the ink applied to the nozzle holes located at both ends in the longitudinal direction becomes the same, and the head pressure applied when the position of the ink supply unit is deviated from the central part in the longitudinal direction of the inkjet head can be made smaller. By doing so, it is possible to prevent the leakage of ink by applying a smaller negative pressure to the nozzle hole, preferably a minimum negative pressure.

According to the third aspect of the present invention, each of the ink holding units has a plurality of ink holding units for holding a plurality of color inks separately and a nozzle hole group for individually discharging the inks of the respective colors. Since the connection portions with the inkjet head are arranged in a direction orthogonal to the longitudinal direction of the inkjet head, the inkjet recording unit for a color printer also has an ink supply unit at the center in the longitudinal direction with respect to the inkjet head of each color. It becomes possible to arrange.

In the invention described in claim 4, the plurality of ink holding portions are arranged side by side in a direction perpendicular to the longitudinal direction of the ink jet head, and the ink holding portions are arranged at different positions in the longitudinal direction of the ink jet head. Since the ink supply units are arranged uniformly around the center, the overall weight balance can be improved.

According to the fifth aspect of the present invention, the plurality of ink holding sections are arranged in a direction orthogonal to the longitudinal direction of the ink jet head and alternately arranged at different positions in the longitudinal direction of the ink jet head. , The overall weight balance can be improved.

According to the inventions described in claims 6 and 7, since the ink jet head is a line head that prints the width direction of the recording medium at a time, the ink jet head stands up so that the longitudinal direction is along the vertical direction. In such a case, the water head pressure applied to the nozzle hole located below the ink supply unit increases, so that the effect of disposing the ink supply unit at the center in the longitudinal direction is large.

The printer of the present invention has an ink jet head for discharging ink from at least nozzle holes to print on a recording medium such as recording paper, and an ink holding unit for holding ink to be supplied to the ink jet head.
The nozzle holes are arranged in the longitudinal direction of the inkjet head, the longitudinal direction of the inkjet head is up and down, and when the inkjet head is set up perpendicular to the horizontal plane, at the extreme end of the inkjet head in the longitudinal direction. In addition, an ink jet recording unit formed by connecting the ink jet head and the ink holding unit is detachably mounted so that the head pressure of the nozzle hole near the horizontal plane becomes a negative pressure.

Therefore, in the printer according to the present invention, the head pressure of the ink applied to the nozzle hole near the horizontal plane at the end in the longitudinal direction of the ink jet head becomes negative pressure regardless of the posture. In addition, leakage of ink can be prevented.

According to the ninth aspect of the present invention, since the ink jet head and the ink holding portion are connected at the central portion in the longitudinal direction of the ink jet head, the ink jet head can be mounted in any posture. The head pressure due to the ink applied to the nozzle holes located at both ends in the longitudinal direction becomes the same, and the head pressure applied when the position of the ink supply unit is deviated from the central part in the longitudinal direction of the inkjet head can be made smaller. By doing so, it is possible to prevent the leakage of ink by applying a smaller negative pressure to the nozzle hole, preferably a minimum negative pressure.

According to the tenth aspect of the present invention, each of the ink holding units has a plurality of ink holding units for holding a plurality of color inks separately and a group of nozzle holes for discharging the respective color inks separately. Since the connection portions with the inkjet head are arranged in a direction orthogonal to the longitudinal direction of the inkjet head, the inkjet recording unit for a color printer also has an ink supply unit at the center in the longitudinal direction with respect to the inkjet head of each color. It becomes possible to arrange.

According to the eleventh aspect of the present invention, the plurality of ink holding portions are arranged side by side in a direction perpendicular to the longitudinal direction of the ink jet head, and the ink holding portions are arranged at different positions in the longitudinal direction of the ink jet head. Since the ink supply units are arranged uniformly around the center, the overall weight balance can be improved.

According to the twelfth aspect of the present invention, the plurality of ink holding portions are arranged side by side in a direction perpendicular to the longitudinal direction of the ink jet head, and are alternately arranged at different positions in the longitudinal direction of the ink jet head. , The overall weight balance can be improved.

In the invention described in claim 13 and claim 14, since the ink jet head is a line head that prints the width direction of the recording medium at a time, the ink jet head stands up so that the longitudinal direction is along the vertical direction. In such a case, the water head pressure applied to the nozzle hole located below the ink supply unit increases, so that the effect of disposing the ink supply unit at the center in the longitudinal direction is large.

[Brief description of the drawings]

FIG. 1 shows a printer according to an embodiment of the present invention together with FIG. 2, and FIG. 1 is a schematic perspective view showing a state in which an ink jet recording unit according to the embodiment of the present invention is removed together with an ink jet head. is there.

FIG. 2 is a schematic perspective view showing a state where an ink jet recording unit is mounted.

FIG. 3 conceptually shows the ink jet recording unit of the present invention together with FIG. 4, and FIG. 3 is a perspective view.

FIG. 4 is a sectional view illustrating the concept of an ink jet recording unit.

FIG. 5 is an explanatory diagram for explaining the principle of ink leaking from the nozzle holes together with FIG. 6, and FIG. 5 shows a case where the present invention is not employed.

FIG. 6 shows a case where the present invention is adopted.

FIG. 7 is a schematic perspective view showing a comparative example in which the arrangement of the ink holding unit in the ink tank is considered together with FIG. 8;

FIG. 8 is a schematic perspective view showing an improved example.

9 shows an embodiment of the ink jet recording unit of the present invention together with FIGS. 10 to 15, and is a cross-sectional view of the ink jet recording unit. FIG.

FIG. 10 is an exploded cross-sectional view of a main part showing connection parts of an ink tank, an inkjet head, and a frame.

11 shows a housing of the ink tank together with FIG. 12, and FIG. 11 is a plan view.

FIG. 12 is a sectional view taken along the line XII-XII in FIG. 11;

FIG. 13 is a longitudinal sectional view of the inkjet head.

14 shows a frame together with FIG. 15, and FIG. 14 is a plan view.

FIG. 15 is a longitudinal sectional view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Printer, 4 ... Recording paper (recording medium), 7 ... Inkjet head, 8 ... Ink holding part, 9 ... Inkjet recording unit, 10 ... Inkjet recording unit
11 ... inkjet head, 13B, 13M, 13
C, 13Y: ink holding unit, 14: nozzle hole, 14y ...
When the ink jet head is set up vertically with respect to the horizontal plane, the nozzle hole at the end of the ink jet head in the longitudinal direction and close to the horizontal plane, 21... Direction, 10A: inkjet recording unit, 10B: inkjet recording unit, 100: inkjet recording unit, 115B, 115M, 115C, 115Y
... Ink holding unit, 120 ... Inkjet head, 12
1a: Nozzle hole, 125: Ink receiving unit (ink supply unit)

Claims (14)

[Claims] 1. An ink jet head, comprising: an ink jet head that discharges ink from at least nozzle holes to print on a recording medium such as a recording paper; and an ink holding unit that holds ink to be supplied to the ink jet head. The nozzle holes are arranged in the longitudinal direction of the inkjet head, the longitudinal direction of the inkjet head is up and down, when the inkjet head is set up perpendicular to a horizontal plane, at the end of the inkjet head in the longitudinal direction, and An ink jet recording unit, wherein the ink jet head and the ink holding unit are connected such that a water head pressure of a nozzle hole near a horizontal plane becomes a negative pressure. 2. The ink jet recording unit according to claim 1, wherein the ink jet head and the ink holding section are connected at a central portion in a longitudinal direction of the ink jet head. 3. An ink jet head comprising: a plurality of ink holding units for separately holding a plurality of color inks; and a group of nozzle holes for discharging the respective color inks separately. 2. The ink jet recording unit according to claim 1, wherein the ink jet recording units are arranged in a direction perpendicular to a longitudinal direction of the ink jet recording apparatus. 4. The ink holding sections are arranged in a direction perpendicular to the longitudinal direction of the ink jet head, and are arranged at different positions in the longitudinal direction of the ink jet head evenly around the ink supply section. The inkjet recording unit according to claim 3, wherein: 5. The ink-jet printing apparatus according to claim 1, wherein the plurality of ink holding units are arranged in a direction orthogonal to the longitudinal direction of the inkjet head, and are alternately arranged at different positions in the longitudinal direction of the inkjet head. 4. The ink jet recording unit according to 3. 6. The ink jet recording unit according to claim 1, wherein the ink jet head is a line head that prints at once in a width direction of a recording medium. 7. The ink jet recording unit according to claim 3, wherein the ink jet head is a line head that prints at once in a width direction of a recording medium. 8. An ink-jet head, comprising: an ink-jet head that discharges ink from at least nozzle holes to print on a recording medium such as recording paper; and an ink holding unit that holds ink to be supplied to the ink-jet head. The nozzle holes are arranged in the longitudinal direction of the inkjet head, the longitudinal direction of the inkjet head is up and down, and when the inkjet head is set up perpendicular to a horizontal plane, at the end of the inkjet head in the longitudinal direction, and A printer, wherein an ink jet recording unit formed by connecting the ink jet head and the ink holding unit is detachably mounted such that a water head pressure of a nozzle hole close to a horizontal plane becomes a negative pressure. 9. The printer according to claim 8, wherein the ink jet head and the ink holding unit are connected at a central portion in a longitudinal direction of the ink jet head. 10. An ink jet head comprising a plurality of ink holding portions for holding inks of a plurality of colors, respectively, and a group of nozzle holes for discharging inks of the respective colors, wherein a connection portion of each ink holding portion with an ink jet head is an ink jet head. 9. The printer according to claim 8, wherein the printers are arranged in a direction orthogonal to a longitudinal direction of the printer. 11. The ink holding units are arranged in a direction orthogonal to the longitudinal direction of the ink jet head, and are arranged at different positions in the longitudinal direction of the ink jet head evenly around the ink supply unit. The printer according to claim 10, wherein: 12. The ink-jet printing apparatus according to claim 1, wherein the plurality of ink holding units are arranged side by side in a direction orthogonal to the longitudinal direction of the inkjet head, and are alternately arranged at different positions in the longitudinal direction of the inkjet head. The printer according to 10. 13. The printer according to claim 8, wherein the ink-jet head is a line head that prints at once in a width direction of a recording medium. 14. The printer according to claim 10, wherein the ink jet head is a line head that prints at once in a width direction of a recording medium.