JP2003154679A - Damper device for inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide damper devices for an inkjet printer which surely prevents air bubbles accumulated in the damper chambers from entering an inkjet head through filters. SOLUTION: The damper devices 14 and 15 are incorporated with a head unit 4 of the inkjet printer. The damper devices 14 and 15 are equipped with flat rectangular parallelepiped shape damper chambers 27 and 28. One of the confronted internal end surfaces having wider areas is restricted by damper films 25 and 26, and the other is restricted by a recess 63 for forming the damper chambers. The damper chambers 27 and 28 communicate with an ink chamber 58 of a small capacity through a communicating port which is formed on the internal side surface 65 on the front sides of the damper chambers 27 and 28. Then, the filters 18 and 19 are attached to an area on the front side of a front side communicating port 59 of the ink chamber 58. Air bubbles 71 accumulated in the damper chambers 27 and 28 are prevented from coming into contact with the filters 18 and 19. Therefore, the air bubbles 71 are surely prevented from entering the head tip 12 side through the filters 18 and 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial type ink jet printer in which ink is supplied from an ink tank arranged at a fixed position. More specifically, the present invention relates to a serial type ink jet printer. The present invention relates to a damper device for absorbing pressure fluctuations.

[0002]

2. Description of the Related Art In a serial type ink jet printer in which a flexible ink tube is connected between an ink tank arranged at a fixed position and a head unit mounted on a carriage, the head unit is moved by the carriage. Then, pressure acts on the ink supplied to the head unit. This pressure is proportional to the acceleration of the head unit, the length of the ink flow path from the ink tank to the head unit, and the specific gravity of the ink. When this pressure acts on the ink nozzles of the head unit, it becomes impossible to properly eject ink droplets, which causes printing defects such as ink droplet scattering and dot dropouts.

Therefore, the head unit is provided with a damper device for absorbing the pressure acting on the ink flow path as the head unit moves. For example, Japanese Patent Application Laid-Open No. 11-192721 discloses an ink jet printer provided with such a damper.

As disclosed in this publication,
The damper device includes a flat damper chamber in which a flexible damper film is attached to a wide-area end surface, and the damper film bends in an out-of-plane direction in response to a change in ink pressure, thereby reducing the pressure. Absorbing. Further, a filter is attached to the damper chamber in order to remove foreign matter from the ink supplied from the damper chamber to the inkjet head.

The damper chamber is generally in the shape of a flat rectangular parallelepiped, and the damper film is attached to one of a pair of large inner end faces facing each other on the inner face of the damper so that the damper characteristics are best exhibited. . Further, the filter is generally attached to the other inner end surface facing the inner end surface to which the damper film is attached. Alternatively, as disclosed in the above-mentioned publication, it is arranged in a damper chamber between a pair of inner end faces having a large area so as to be parallel to them.

[0006]

Here, as shown in FIG. 9, when a bubble 101 enters the damper chamber 100, the bubble 101 accumulates above the damper chamber. A pair of narrow inner surface 1
02 and 103 are in contact with each other, and bubbles 101
Is increased, the inner side surfaces 104 and 105 having a small area connecting the inner end surfaces 102 and 103 to each other are also in contact with each other.

A filter 106 is arranged on the inner end surface 103, and when the bubble 101 is in contact with the filter 106, ink is sucked from a nozzle of an ink jet head by an ink suction pump as shown in FIG. 9B, for example. When the operation is performed, an ink suction force larger than that in the normal printing state shown in FIG. 9A acts, so that the bubbles 101 in contact with the filter pass through the filter 106 and enter the inkjet head side. There is a risk of If air bubbles enter the inkjet head, ink ejection failure will occur in the ink nozzles, and in some cases ink ejection failure such as dot omission will occur, resulting in deterioration of print quality, which is not preferable.

Therefore, an object of the present invention is to propose a damper device for an ink jet printer which is constructed so that bubbles in the damper chamber do not enter the ink jet head side.

[0009]

In order to solve the above problems, the present invention relates to a damper device for an ink jet printer which absorbs pressure fluctuations of ink supplied to an ink jet head. And a filter for removing foreign matter contained in ink supplied to the inkjet head, wherein the damper chamber has a pair of inner end surfaces facing each other and a plurality of inner surfaces connecting the inner end surfaces. The inner end surface has a larger area than the inner side surface, and the filter is attached to a communication port formed in one of the inner side surfaces.

Here, it is desirable that one of the inner end surfaces is formed of a flexible damper film.

The distance between the pair of inner end surfaces is
It is desirable that the distance between the inner side surfaces is narrower.

In general, the damper chamber may have a flat rectangular parallelepiped shape or a polygonal prism shape.

In the damper device of the present invention, the filter is not attached to the pair of inner end surfaces having a large area, but the filter is attached to one of the other inner side surfaces having a small area. The bubbles accumulated in the damper chamber are likely to come into contact with the inner end surface having a large area, but are less likely to come into contact with the inner side surfaces having a small area and separated from each other. Therefore, according to the present invention, since it is difficult for the residual air bubbles in the damper chamber to contact the filter, it is possible to prevent or suppress the invasion of the air bubbles into the inkjet head from the damper chamber through the filter.

Next, according to the present invention, in a damper device of an ink jet printer that absorbs pressure fluctuations of ink supplied to an ink jet head, a damper chamber, an ink chamber having a smaller volume than the damper chamber, and the ink chamber The damper chamber has a filter for removing foreign matter contained in the ink supplied to the inkjet head, and the damper chamber has a pair of inner end surfaces facing each other and a plurality of inner surfaces connecting the inner surfaces. And a side surface, the inner end surface has a larger area than the inner side surface,
The damper chamber is characterized by communicating with the ink chamber through a communication port formed on one of the inner side surfaces.

Here, it is desirable that one of the inner end surfaces is formed of a flexible damper film.

The distance between the pair of inner end surfaces is
It is desirable that the distance between the inner side surfaces is narrower.

Further, the damper chamber may have a flat rectangular parallelepiped shape or a polygonal prism shape.

In the damper device of the present invention, a communication port is formed on the side of the inner side surface where the area of the damper chamber is small, and an ink chamber is formed through this, which communicates with the damper chamber, and a filter is arranged therein. There is. Therefore, the filter is in a position retracted from the inner side surface of the damper chamber. Therefore, it is possible to prevent the bubbles accumulated in the damper chamber from coming into contact with the filter, so that it is possible to reliably prevent the bubbles from entering the inkjet head through the filter.

Next, the present invention relates to an ink jet printer, which is characterized in that it is provided with the damper device having the above construction in order to absorb the pressure fluctuation of the ink supplied to the ink jet head.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a head unit of an ink jet printer equipped with a damper device to which the present invention is applied will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a main part of an ink jet printer in which the head unit of this example can be mounted. The inkjet printer 1 is a serial type, and a head unit 4 is mounted on a carriage 3 that can reciprocate along a guide shaft 2. Ink is supplied to the head unit 4 from an ink tank 5 arranged at a fixed position via a flexible ink tube 6. In this example, color ink and black ink are supplied from the ink tanks 5-1 and 5-2 to the head unit 4 via the two ink tubes 6-1 and 6-2.

FIG. 2 is a perspective view of the head unit 4 of this embodiment as viewed from the front side, FIG. 3 is a perspective view of the head unit 4 as viewed from the rear side, and FIG. 4 is a line IV-IV in FIG. FIG. 5 is a cross-sectional view showing a cut portion, and FIG. 5 is a vertical cross-sectional view showing a portion cut along the line VV of FIG. 4. Further, FIG. 6 is an exploded perspective view thereof.

Explaining with reference to these figures, the head unit 4 of this example is provided with a unit cover 11 having an opening on the rear side, and each component of the head unit is housed in this unit cover 11. Has been done. That is, in the unit cover 11, a head chip (ink jet head) 12, a unit substrate 13, a pair of left and right damper devices 14 and 15, and a relay substrate 16 are stacked in this order from the front side. A slip-off prevention plate 17 is arranged between the left and right damper devices 14 and 15. Further, the damper devices 14 and 15 of this example include filters 18 and 19 between the damper devices 14 and 15 for removing foreign matters from the ink supplied to the head chip 12. A cover head 20 is laminated on the front surface of the unit cover 11.

The damper devices 14 and 15 have a symmetrical shape, and the damper cases 21 and 22 attached to the unit cover 11 and the damper cases 2 are provided, respectively.
1 and 22, and flexible damper films 25 and 26 that seal the recesses 23 and 24 for the damper chambers formed in the parts 1 and 22, respectively. By the recess 23 and the damper film 25, the recess 24 and the damper film 26, respectively. The damper chambers 27 and 28 are partitioned and formed.

Ink tubes 6-1 and 6-2 are connected to the damper chambers 27 and 28, respectively.
Each ink is supplied from -1, 5-2. Each damper room 2
The ink supplied to Nos. 7 and 38 is supplied to the head chip 12 via the filters 18 and 19.

The unit cover 11, the unit substrate 13, the damper cases 21 and 22, the slip-off prevention plate 17, and the cover head 18 can be formed of, for example, resin molded products.
Further, the damper films 25 and 26 of this example are rubber films.

Next, the structure of each part will be described. First, the head chip 12 has a flat rectangular parallelepiped shape, and a front surface 12a thereof is an ink nozzle surface, and two ink nozzle rows (not shown) for ejecting ink of each color are formed here. . The ink nozzle surface 12a is exposed from the front opening 11a of the unit cover 11 and the front opening 20a of the head cover 20. In addition, from each side surface of the head chip 12, a flexible wiring board 31 for power supply is provided.
-1, 31-2 are pulled out, and are pulled out to the rear along the inside of each side surface of the unit cover 11, and the relay board 1
6 is connected to the front surface. Each flexible wiring board 3
The head chip driving IC 32-1 is provided in a portion of each of 1-1 and 31-2 facing each side surface of the unit substrate 13.
32-2 is attached.

The unit substrate 13 to which the head chip 12 is attached has a front plate portion 41 (chip mounting portion) to which the head chip 12 is adhered and fixed to the front surface 41a, and the front plate portion 41 from the top to the rear. An upper plate portion 42 and a lower plate portion 43 extending at right angles are provided. The rear surface 41b of the front plate portion 41 and the upper plate portion 42 and the lower plate portion 43
The dampers 14 and 15 are assembled between them.

Here, on the front surface 41a of the front plate portion 41,
An adhesive groove 44 for filling an adhesive for fixing the head chip 12 by adhesion is formed here. An insertion groove 45 extending vertically is formed at the center of the rear surface 41b of the front plate portion 41, and the removal prevention plate 17 is provided there.
Can be inserted. In addition, a slide groove 46 of a constant width that horizontally extends inward from the left and right side surfaces of the upper plate portion 42,
47 is formed. These slide grooves 46, 47
It is possible to assemble the damper devices 14 and 15 to the unit board 13 from the left and right sides along the line.

In addition, inside the front plate portion 41, an ink supply path 4 for supplying each ink to each two ink intake ports 33 and 34 formed in the head chip 12.
8 and 49 are formed, and these ink supply paths 48,
The damper-side communication ports 48a and 49a of the front plate portion 49 are the rear surface 4
It is exposed to 1b. The communication ports 48a, 49 on the damper side
The filters 18 and 1 of the damper devices 14 and 15 respectively.
Each 9 is attached by heat fusion or an adhesive.

Next, FIG. 7 is a sectional view showing one damper device 14 taken out. The damper devices 14 and 15 and the slip-out prevention plate 17 will be described with reference to this drawing as well. Since each of the damper devices 14 and 15 has a bilaterally symmetrical structure, only one damper device 14 will be described, and the corresponding parts in the other damper device 15 are given the same numbers,
The description thereof will be omitted.

As described above, the damper device 14 includes the damper case 21, the recess 23 for forming the damper chamber formed therein, and the damper film 25 sealing the recess 23. A damper chamber 27 is defined by the damper film 25. More specifically, the damper case 21 is formed with a rectangular recess 23 having a constant depth, and the rectangular opening 51 of the recess 23 faces the side of the slip-out prevention plate 17 and has a rectangular frame shape. Opening edge surface 52
Is a rear surface 41b of the front plate portion 41 of the unit substrate 13.
Vertical to. A rectangular frame-shaped press-fitting groove 53 having a constant width is formed in the opening edge surface 52. The opening-side portion of the press-fitting groove 53 is expanded in a tapered shape. On the other hand, the damper film 25 is a rubber film having a constant thickness as a whole, and a rectangular frame-shaped press-fitting protrusion 54 is formed on one surface thereof along the outer peripheral edge portion. The height dimension of the press-fitting protrusion 54 is smaller than the depth dimension of the press-fitting groove 53, but the width dimension thereof is larger than the width of the press-fitting groove 53 by the press-fitting margin. Therefore, when the press-fitting projection 54 of the damper film 25 is forcibly pushed into the press-fitting groove 53, the press-fitting projection 54 can be elastically deformed and press-fitted and fixed in the press-fitting groove 53 on the damper case side.
In the state of being press-fitted and fixed, the side surface of the press-fitting protrusion 54 is in close contact with the side surface of the press-fitting groove 53, so that the damper chamber 27 in a sealed state is formed.

An ink supply passage 55 is communicated with a portion of the concave portion 23 on the bottom side of the side surface on the rear side of the head unit. The ink supply passage 55 horizontally projects rearward from the rear end surface of the damper case 21.
Is in communication with. One side of the ink tubes 6-1 and 6-2 is connected to the ink supply pipe 56, and ink is supplied to the damper chamber via the one side.

Further, in the damper 14 of this embodiment, a rectangular communication port 57 is opened in the bottom surface portion of the recess 23 on the front side of the head unit, and an ink chamber 58 having a smaller volume than the recess 23 is formed on the front side. Has been done. A front end opening 59 of the ink chamber 58 is exposed from the front end surface of the damper case 21, and the front end opening 59 is located in the unit substrate 13.
Damper side communication port 48a formed in the front plate portion 41 of the
Is in communication with.

That is, the damper chamber 27 of the present embodiment is a flat rectangular parallelepiped chamber extending in the front-rear direction of the head unit, and of the six inner planes defining the inner peripheral surface of the damper chamber 27, the pair of left and right sides has the largest area. The inner end surface is defined by the damper film 25 and the recess bottom surface 63, the ink supply path 55 is formed in the rear inner side surface 64, and the ink is supplied to the head chip side in the front inner side surface 65 and the front portion of the bottom surface 63. The ink chambers 58 that communicate with each other communicate with each other, and ink is supplied to the head chip 12 side through the ink chambers 58. Also,
The front end opening 59 in the ink chamber 58 is separated from the inner side surface of the damper chamber 27 toward the front of the head unit, and the filter 18 is attached to the damper side communication port 48a on the unit substrate 13 side so as to communicate with the front end opening 59. .

On the other hand, as shown in FIG. 6, the damper case 2
A slide protrusion 60 that can be horizontally inserted into a slide groove 46 formed in the upper plate portion 42 of the unit substrate 13 is formed on the upper surface portion of 1.

Next, the slip-off prevention plate 17 is arranged between the pair of left and right dampers 14 and 15, and is almost a damper film 25.
A rectangular frame portion 71 having a size corresponding to the rectangular frame-shaped press-fitting projection 54 formed on the upper surface and a positioning projection 7 formed on the upper end surface and the lower end surface of the rectangular frame portion 71 and protruding vertically.
2, 73 and an insertion portion 74 extending forward from the front end of the rectangular frame portion 71. The insertion portion 74 can be vertically inserted from the rear side into the insertion groove 45 formed in the rear surface 41b of the front plate portion 41 of the unit substrate 13. Further, the upper and lower positioning projections 72 and 73 are also provided with positioning grooves 75 and 76 (positioning groove 75 in the figure) formed in the upper plate part and the lower plate part of the unit board 13 as well.
Show only. ) Can be inserted from the rear side.

In the damper devices 14 and 15 of the head unit 4 of the present embodiment thus configured, the damper chambers 27 and 28 have a flat rectangular parallelepiped shape, and one of the pair of inner end faces having a large area has one of them. The filters 18, 19 are defined by the damper films 25, 26, and the filter chambers 27, 28
Is disposed in a portion communicating with the front end opening 59 of the ink chamber 58 having a small volume communicating with the.

Therefore, even when bubbles are accumulated in the damper chambers 27 and 28, the bubbles are directly absorbed by the filters 18 and 1.
I never touch 9. That is, as schematically shown in FIG. 8, air bubbles 71 accumulated in the upper portions of the damper chambers 27 and 28 are collected.
Is the inner end surface having a wide area (the damper films 25, 2) facing each other.
Although it is in a state of contact between the surface of 6 and the bottom surface 63) of the recess, it does not contact the filters 18, 19 on the side of the ink chamber 58 which is distant from the damper chambers 27, 28. Therefore, FIG.
Even in the printing state as shown in FIG.
Even in the ink suction state where the ink suction pressure is high as shown in (b), the bubbles 71 do not come into contact with the filters 18 and 19, so that the bubbles can be prevented from entering the head chip 12 side.

(Other Embodiments) In the damper devices 14 and 15 described above, the filters 18 and 19 are arranged on the side of the small volume ink chamber 58 communicating with the damper chambers 27 and 28. The ink chamber 58 is omitted, and the filters 18 and 19 are not formed on the one inner end surface having a large opposing area (in the above example, the concave bottom surface 63 facing the damper films 25 and 26). Alternatively, it is possible to adopt a configuration in which it is attached to the inner side surface having a small area. In the above example, it may be attached to the inner side surface 65.

Even when this structure is adopted, the bubbles in the damper chamber come into contact with the pair of opposing inner end faces, but are less likely to come into contact with the inner side faces having a small area and wide intervals. Therefore, it is possible to prevent or suppress the bubbles in the damper chamber from entering the inkjet head side.

Although the damper chamber has a flat rectangular parallelepiped shape in the above example, it may have a flat polygonal column shape. In any case, it is preferable that the distance between the inner end surfaces having a large area facing each other is wider than the distance between the inner side surfaces having a small area, because bubbles are less likely to contact the inner side surfaces.

[0043]

As described above, in the damper device of the ink jet printer of the present invention, a filter is not arranged on a pair of inner end surfaces having a wide area facing each other among the inner surfaces forming the damper chamber. In addition, the filter is placed on the inner side surface with a small area. Therefore, as compared with the case where the filter is arranged on the inner end surface facing the damper film as in the related art, the bubbles remaining in the damper chamber are less likely to come into contact with the filter, so that the bubbles pass through the filter to the side of the inkjet head. Can be prevented or suppressed. Further, since it is possible to prevent or suppress the area of the filter that is in contact with the ink (filter effective area) from being reduced by bubbles, it is possible to always ensure a sufficient effective area of the filter.

Furthermore, since the damper film is attached to the inner surface of the damper chamber having a large area, the damper characteristics can be set appropriately.

Furthermore, since the distance between the inner end surfaces having a large area is set to be narrower than the distance between the inner side surfaces having a small area, it is possible to reliably prevent bubbles from coming into contact with the inner side surfaces having a large distance. Therefore, it is possible to reliably prevent the bubbles from entering the inkjet head from the damper chamber.

Next, in the damper device of the present invention, since the ink chamber having a small volume communicating with the damper chamber is formed and the filter is arranged in this ink chamber, the bubbles accumulated in the damper chamber come into contact with the filter. It can be surely avoided. Further, since it is possible to prevent or suppress the area of the filter that is in contact with the ink (filter effective area) from being reduced by bubbles, it is possible to always ensure a sufficient effective area of the filter.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a main part of a serial type inkjet printer to which the present invention is applied.

FIG. 2 is a perspective view of the head unit of FIG. 1 when viewed from the front side.

FIG. 3 is a perspective view of the head unit of FIG. 1 when viewed from the rear side.

FIG. 4 is a transverse cross-sectional view showing a portion cut along line IV-IV in FIG.

5 is a vertical cross-sectional view showing a portion cut along line VV in FIG.

FIG. 6 is an exploded perspective view of the head unit of FIG.

7 is a cross-sectional view showing a damper incorporated in the head unit of FIG.

8A and 8B are explanatory diagrams showing a function and effect of the damper device of the head unit of FIG.

FIG. 9 is an explanatory diagram showing a problem of the conventional damper device.

[Explanation of symbols]

1 inkjet printer 2 Guide shaft 3 carriage 4 head unit 5 ink tank 6 ink tubes 11 unit cover 11a Front opening 12 head chips 12a Ink nozzle surface 13 unit board 14, 15 Damper device 16 Relay board 17 Prevention plate 18, 19 filters 20 head cover 21, 22 damper case 23, 24 recess 25, 26 Damper film 27, 28 damper room 33, 34 ink intake 41 Front plate part (chip mounting part) 41a front 41b rear 45 slot 51 Opening of recess 55 ink supply path 58 ink chamber 63 Inner end face of large area of damper chamber (bottom of recess) 64,65 Inside surface of damper chamber with small area 59 communication port 71 air bubbles

Claims (9)

[Claims] 1. A damper device for an inkjet printer that absorbs pressure fluctuations of ink supplied to an inkjet head, wherein a damper chamber and foreign matter contained in the ink supplied to the inkjet head from the damper chamber are removed. The damper chamber is defined by a pair of inner end surfaces facing each other and a plurality of inner side surfaces connecting between the inner end surfaces, and the inner end surface is wider than the inner side surface. A damper device for an inkjet printer, wherein the damper is an area and the filter is attached to the inner side surface. 2. The damper device for an inkjet printer according to claim 1, wherein one of the inner end surfaces is formed of a flexible damper film. 3. The damper device for an inkjet printer according to claim 1, wherein a distance between the pair of inner end surfaces is smaller than a distance between the inner side surfaces. 4. The damper device for an ink jet printer according to claim 3, wherein the damper chamber has a flat rectangular parallelepiped shape or a polygonal prism shape. 5. A damper device for an inkjet printer, which absorbs pressure fluctuations of ink supplied to an inkjet head, a damper chamber, an ink chamber having a volume smaller than that of the damper chamber, and the ink chamber supplied to the inkjet head. And a filter for removing foreign matter contained in the ink, wherein the damper chamber is formed by a pair of inner end surfaces facing each other and a plurality of inner side surfaces connecting the inner surfaces. The inner end surface has a larger area than the inner side surface, and the damper chamber communicates with the ink chamber through a communication port formed on the inner side surface side. Damper device. 6. The damper device for an ink jet printer according to claim 5, wherein one of the inner end surfaces is formed of a flexible damper film. 7. The damper device for an inkjet printer according to claim 5, wherein a distance between the pair of inner end surfaces is smaller than a distance between the inner side surfaces. 8. The damper device for an ink jet printer according to claim 7, wherein the damper chamber has a flat rectangular parallelepiped shape or a polygonal prism shape. 9. An ink jet printer comprising the damper device according to any one of claims 1 to 8.