JP2003305867A - Ink jet head unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of the ink ejection failure derived from the bubble stationary point in the ink channel, stagnating the bubbles even after discharging the bubbles, which are moved to the ink jet head side by disturbance such as vibration and environment change in a conventional filter fusion method with the risk of generating a bubble stationary point by deformation of an ink channel due to heat or pressure at the time of fusing the filter, or introduction of the fused part to the ink channel. <P>SOLUTION: In the ink jet head unit comprising an ink jet head for ejecting an ink onto a recording paper for executing a recording operation, an ink channel for supporting the ink jet head and supplying the ink to the ink jet head, and a base having a filter installing part, the filter installing part comprises a fusion surface surrounding the ink channel, a fusion projection and a groove such that the filter is fused and fixed onto the fusion surface via the fusion projection. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head unit in which an ink jet head and an ink tank are integrated or separable, and more particularly to an ink jet head unit having a filter in an ink flow path to the ink jet head. .

[0002]

2. Description of the Related Art Heretofore, there has been known an ink jet head unit for fusing a filter in an ink flow path as disclosed in JP-A-8-80616 and FIG.

[0003]

However, in the conventional method, there is a possibility that air bubbles may be stopped due to heating at the time of fusion of the filter, deformation of the ink flow passage due to pressing, or entry of the fusion portion into the ink flow passage. there were.

Generally, in an ink jet printer, suction is performed by a pump from the nozzle side of the ink jet head to discharge air bubbles in the head unit. However, if there is a bubble stop point in the ink flow path, the bubble will remain even after discharging the bubble, and the trapped bubble will move to the inkjet head side due to disturbances such as vibration and environmental changes, causing ink ejection failure. Not preferable.

Therefore, an object of the present invention is to propose an ink jet head unit which has a high bubble discharge property without bubble stop points due to deformation of the ink flow path or penetration of the fused portion into the ink flow path.

[0006]

In order to solve the above problems, the present invention provides an ink jet head for ejecting ink onto a recording paper for recording, and an ink jet head for holding the ink jet head and supplying the ink to the ink jet head. In an inkjet head unit including a base having an ink flow path and a filter installation section, the filter installation section is composed of a fusion surface, a fusion projection and a groove surrounding the ink flow channel, and the filter is a fusion projection. It is characterized in that it is fusion-bonded and fixed to the fusion-bonding surface via.

Here, the fusion-bonding protrusion has a substantially triangular shape, and an angle formed by the ink-flow-side slope and the fusion-bonding surface is smaller than an angle formed by the groove-side slope and the fusion-bonding surface. Is desirable.

Further, the fusing protrusion has a substantially triangular shape, and an angle formed between the ink flow path side inclined surface and the fusing surface is smaller than an angle formed between the groove side inclined surface and the fusing surface. desirable.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an inkjet head unit (hereinafter referred to as a head unit) of an inkjet printer 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.

2 is a perspective view of the head unit 4 of this embodiment as seen from the front side, FIG. 3 is a perspective view of the head unit 4 as seen 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 whose rear side is open, and inside this unit cover 11, each component of the head unit is housed. 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 respectively include the damper cases 21 and 22 attached to the unit cover 11 and the damper cases 2 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 attachment 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.

Further, inside the front plate portion 41, an ink supply passage 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 19 of the damper devices 14 and 15 are attached to a by thermal fusion.

Next, FIG. 7 is a sectional view showing one of the damper devices 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 uniform 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 surface side of 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 example 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 left and right pair of chambers 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, 73 are also inserted from the rear side into positioning grooves 75, 76 (only the positioning groove 75 is shown in the figure) formed in the upper plate portion and the lower plate portion of the unit board 13 as well. Can be included.

In the damper devices 14 and 15 of the head unit 4 of the present embodiment thus constructed, the damper chambers 27 and 28 are formed into a flat rectangular parallelepiped shape, and one of the pair of inner end faces having a large area is formed. The filters 18, 19 are defined by the damper films 25, 26, and the filters 18, 19 are arranged in the damper 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.

Next, FIG. 8 shows a filter fusion bonding portion 80 of the base 13.
Fig. 9 shows a cross-sectional view of Fig. 9, and Fig. 9 shows a top view of the filter fusion-bonded portion. Since the filter fusing part 80 has a bilaterally symmetrical shape, only one of the filter fusing parts 80 will be described.
A filter fusing part 80 for fusing the filter 18 is formed on the upper portion of the ink flow path 48. The filter fusion bonding portion 80 is formed of a material that melts at a constant temperature as described above, for example, a polymer material such as a thermoplastic resin. The filter 18 is made of metal such as stainless steel and has a mesh shape or a fiber shape and is formed so as to allow ink to pass through but block passage of foreign matter.

The ink channel 48 on the head chip 12 side of the filter 18 has a shape narrowed toward the head chip 12 side. The filter fusing part 80 is the fusing surface 4
1c and a positioning wall 41f for a filter that stands upright on the fusion surface 41c. Further, a fusion-bonding protrusion 41d and a groove 41e are formed on the fusion-bonding surface 41c. Fusing protrusion 41
The d and the groove 41e are formed so as to surround the ink flow path, and the cross-sectional shape of the fusion-bonding protrusion 41d is trapezoidal.

Next, a method for fusion-bonding and fixing the filter will be described. FIG. 10 is an explanatory view of the fusing operation, and FIG. 11 is a filter fusing unit 80.
FIG. 4 is a cross-sectional view after the filter is fused.

(1) Pressing stroke of the filter 18 The filter 18 is fitted into the filter fusion portion 80 of the base 13 and placed on the fusion protrusion 41d. At this time, the positioning wall 41f of the filter fusing part 80 serves as a guide wall of the filter 18 and can be placed on the fusing protrusion 41d without displacement. The fusing jig 90, which has been heated to a predetermined temperature in advance, is lowered from above and brought into contact with the filter 18.

(2) Filter fusion process The heat of the fusion jig 90 is transmitted to the fusion protrusion 41d of the fusion surface 41c of the filter fusion portion 80 through the filter 18.
The fusion-bonding protrusion 41d is heated and melted. At this time, if the fusing jig 90 is lowered by the height H of the fusing protrusion 41d, the molten material enters the fine holes of the filter 18 by the pressing force of the fusing jig 90. After that, when the fusing jig 90 is raised, the melted material is entangled with the mesh of the filter 18 to be cooled and solidified, and the filter 18 is fused to the fusion surface 41c.
Fixed to.

During the fusion process, the fusion surface 41c is also heated and may be deformed by the pressing force of the fusion jig 90. In this embodiment, the groove 41e is provided outside the fusion protrusion 41d. The attachment protrusion 41d is easily deformed outward from the ink flow path 48. As a result, the deformation of the ink flow path 48 can be reduced, and the fused fusion protrusion 41 can be formed.
The d does not enter the ink flow path 48 to create a bubble stopping point.

(Other Embodiments) FIG. 12 shows a second embodiment according to the present invention, in which the same parts as those in the first embodiment are designated by the same reference numerals and their description is omitted. In this example,
The fusing protrusion 41d has an asymmetrical trapezoidal cross-sectional shape, and the angle θ1 formed by the slant surface 41d-1 on the ink flow path 48 side and the fusing surface 41c is the same as the slant surface 41d-2 on the groove 41e side and the fusing surface 41c.
Is smaller than the angle θ2 formed by. As a result, the deformation of the ink flow path 48 can be further reduced, and the fused fusion protrusion 41d does not enter the ink flow path 48 to create a bubble retention point.

(Other Embodiments) FIG. 13 shows a third embodiment according to the present invention, in which the same parts as those in the first embodiment are designated by the same reference numerals and their description is omitted. In this embodiment, the cross-sectional shape of the fusion-bonding protrusion 41d is an asymmetrical triangular shape, and the slope 41d-1 on the ink flow path 48 side and the fusion-bonding surface 41c are formed.
Is smaller than the angle θ2 formed between the inclined surface 41d-2 on the groove 41e side and the fusion-bonded surface 41c. As a result, the deformation of the ink flow path 48 can be further reduced, and the fused fusion protrusion 41d does not enter the ink flow path 48 to create a bubble retention point.

[0038]

As described above, in the head unit of the present invention, the deformation of the ink flow passage is suppressed when the filter is fused to the base, and the fusion protrusion does not enter the ink flow passage. There is no stopping point. Therefore, it is possible to obtain a highly reliable head unit in which there is no ink ejection failure due to the remaining bubbles.

Further, if the shape of the fusion-bonding protrusion of the base is substantially triangular, the angle formed by the slope on the ink flow path side and the fusion-bonding surface is smaller than the angle formed by the slope on the groove side and the fusion-bonding surface. , A more reliable head unit can be obtained.

Furthermore, the shape of the fusion-bonding protrusion of the base is substantially trapezoidal, and the angle formed by the slope on the ink flow path side and the fusion-bonding surface is smaller than the angle formed by the slope on the groove side and the fusion-bonding surface. If so, a more reliable head unit can be obtained.

[Brief description of drawings]

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

FIG. 2 is a perspective view of the head unit of the first embodiment as viewed from the front side.

FIG. 3 is a perspective view of the head unit of the first embodiment as 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 according to the first embodiment.

FIG. 7 is a sectional view showing a damper incorporated in the head unit of the first embodiment.

FIG. 8 is a cross-sectional view showing a filter fusion bonding portion of the first embodiment.

FIG. 9 is a top view showing a filter fusion-bonding portion of the first embodiment.

FIG. 10 is an explanatory diagram of a filter fusing operation according to the first embodiment.

FIG. 11 is a cross-sectional view after fusion of the filter according to the first embodiment.

FIG. 12 is a sectional view for explaining a second embodiment according to the present invention.

FIG. 13 is a sectional view for explaining a third embodiment according to the present invention.

[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 base 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 80 Filter fusion part 90 Fusing jig

Claims (3)

[Claims] 1. An ink jet head unit comprising an ink jet head for ejecting ink onto a recording paper for recording, and a base having an ink flow path and a filter installation portion for holding the ink jet head and supplying ink to the ink jet head. In the above, the filter installation portion is configured by a fusion surface surrounding the ink flow path, a fusion protrusion and a groove, and the filter is fused and fixed to the fusion surface via the fusion protrusion. Inkjet head unit to do. 2. The fusion protrusion according to claim 1, wherein the fusion protrusion has a substantially trapezoidal shape, and an angle formed by the ink flow passage side slope and the fusion face is greater than an angle formed by the groove side slope and the fusion face. Inkjet head unit that is also small. 3. The fusion protrusion according to claim 1, wherein the fusion protrusion has a substantially triangular shape, and an angle formed by the slope on the ink flow path side and the fusion surface is greater than an angle formed by the slope on the groove side and the fusion surface. Inkjet head unit that is also small.