JP2001328281A - Recording head unit, and its recovery mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head unit 70 which can prevent useless discharge of ink during recovery operation. SOLUTION: Fluid resistance of each ink channel is arranged by increasing the cross-sectional area of an ink supply passage in the widthwise direction as the length of a series of ink channels extending from the inlet of an ink supply needle 76 being connected with an ink cartridge 25 to a nozzle opening 20 increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head unit having an ink jet recording head capable of discharging ink from a nozzle opening, and a discharge function of the recording head by forcibly discharging ink from the recording head. And a recovery mechanism for recovering.

[0002]

2. Description of the Related Art The prior art will be described with reference to a printer having an ink jet recording head as an example. This type of printer includes a head unit having a recording head,
Some include an ink cartridge storing ink, and an ink supply path communicating between the ink cartridge and the recording head. The leading end of the ink supply path is constituted by an ink supply needle, and the stored ink is introduced into the ink supply flow path by inserting the ink supply needle into the ink cartridge. The ink cartridge has, for example, four ink chambers, and each ink chamber stores black ink, yellow ink, magenta ink, and cyan ink separately. The ink supply path is a flow path having a substantially circular cross section in the flow path width direction, and four ink supply paths are provided corresponding to the black, yellow, magenta, and cyan inks. The inner diameters of the ink supply paths are substantially the same.

[0003] In this type of printer, there is a risk that the ink near the nozzle opening will thicken due to being left for a long period of time. Since this thickened ink causes a deterioration in functions such as ejection failure and clogging, the printer is provided with a recovery mechanism for forcibly discharging the thickened ink. The recovery mechanism includes, for example, a cap member having a concave portion formed on the surface thereof, and a suction pump communicating with the concave portion through the ink discharge path. In the recovery operation, the cap member is brought into contact with the nozzle surface. Is closed, the suction pump is operated to make the inside of the depression a negative pressure, and the ink is discharged from the nozzle opening to the depression.

[0004]

Since the ink chambers of the ink cartridge are formed separately for each type of ink, the length of each ink supply path varies according to the positional relationship between the communicating ink chamber and the recording head. . Since the inner diameter of each ink supply path is equal, the flow path resistance of each ink supply path also varies according to the length of the ink supply path. Furthermore, in the above-described recovery operation, all nozzle openings are sucked under the same conditions, and thus the amount of discharged ink also varies. For this reason, the suction condition in the recovery operation is set in accordance with the supply path that discharges the least amount of ink. Therefore,
As for the other supply paths, an amount of ink larger than that required for the function recovery is discharged, and the ink is wasted. This causes a problem that the amount of ink used for recording characters and images is reduced.

In recent years, ink cartridges have tended to increase in size so that one cartridge can perform more recordings. On the other hand, recording heads tend to be miniaturized so that the moving range in the main scanning direction can be shortened to achieve high-speed recording. For this reason, the difference between the lengths of the ink supply paths becomes more remarkable, and the amount of wastefully discharged ink is further increased. Further, in a recording head in which the number of nozzle openings is different for each type of ink, the flow resistance of the ink flow path also differs depending on the number of nozzle openings, so that the amount of wastefully discharged ink increases. There is a possibility that it will be.

The present invention has been made in view of such circumstances, and has as its object to provide a recording head unit capable of preventing wasteful discharge of ink during a recovery operation;
An object of the present invention is to provide a recovery mechanism for a recording head unit.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object, and the present invention is directed to a method for controlling the distance from an ink outlet of an ink storage section to an ink inlet of a recording head. A recording apparatus comprising a communication ink supply path, wherein a plurality of types of ink individually stored in an ink storage section are supplied to a recording head through the ink supply path and ejected from a nozzle opening formed on a nozzle surface. In the head unit, a plurality of series of ink flow paths from the inlet of the ink supply path connected to the ink storage section to the nozzle opening are provided in accordance with the type of ink, and the cross-sectional area of the ink supply path is determined by the ink flow path. The recording head unit is characterized in that the longer the length, the greater the fluid resistance of each ink flow path.

According to a second aspect of the present invention, the ink supply path communicates with an inlet-side connecting portion connected to the ink storing portion and a downstream side of the inlet-side connecting portion and converges toward the recording head. The recording head unit according to claim 1, wherein the recording head unit includes a converging flow path portion, and the converging flow path portion is formed in a plate-shaped member.

According to a third aspect of the present invention, the recording head is provided corresponding to the type of ink and has a common ink chamber for storing ink from an ink supply path and a space between the common ink chamber and the nozzle opening. And a plurality of individual ink flow paths communicating the common ink chamber, wherein the cross-sectional area of the ink supply path increases as the number of nozzle openings communicating with the common ink chamber decreases. Recording head unit.

According to a fourth aspect of the present invention, there is provided a recovery mechanism for discharging ink from the recording head unit according to any one of the first to third aspects, wherein the closing member includes a negative pressure air space; A suction mechanism communicating with the compressed air portion, the nozzle opening is made to face the negative pressure air portion, the nozzle surface is sealed by a closing member, and the negative pressure inside the negative pressure air portion is reduced to a negative pressure by the operation of the suction mechanism, so that a plurality of ink flow paths are formed. This is a recovery mechanism for the recording head unit, which collectively sucks the ink.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the illustrated ink jet printer 1 (hereinafter simply referred to as printer 1) has a carriage 3 having a recording head unit 2 (hereinafter simply referred to as head unit 2). . The carriage 3 is reciprocated by the head scanning mechanism in the main scanning direction.

The head scanning mechanism includes a guide member 5 extending in the left-right direction of the housing 4, a drive pulley 7 connected to a rotation shaft of a pulse motor 6 and driven to rotate by the pulse motor 6, and a free-wheel pulley. 8, a timing belt 9 laid between the drive pulley 7 and the idler pulley 8 and connected to the carriage 3, and a control unit (not shown) for controlling the rotation of the pulse motor 6. is there. Further, the printer 1 has a paper feed mechanism for feeding the recording paper 12 in the paper feed direction (sub-scanning direction). The paper feed mechanism includes a paper feed motor 10, a paper feed roller 11, and the like, and sequentially feeds the recording paper 12 in conjunction with a recording operation.

A home position is set in an end area within the moving range of the carriage 3 and outside the recording area. The home position is set to the recording head 13 when the power is turned off or when recording is not performed for a long time.
When the recording head 13 of the head unit 2 is located, the cap member 14 is moved to the surface of the nozzle plate 15 (corresponding to the nozzle surface of the present invention, see FIG. 2).
And sealed. The cap member 14 functions as a closing member that constitutes a part of the recovery mechanism, and is configured by a member formed by molding an elastic material such as rubber into a tray shape. Then, as shown in FIG. 3, the concave portion 16 of the cap member 14 functions as a negative pressure air portion of the present invention, and communicates with the suction pump 18 through the ink discharge path 17. The suction pump 18 functions as a suction mechanism that forms a part of the recovery mechanism. Further, a moisturizing material 19 such as felt is fitted into the concave portion 16. Then, in the sealed state by the cap member 14, the nozzle opening 20 formed in the nozzle plate 15 faces the inside of the concave portion 16. Therefore, when the suction pump 18 is operated in this sealed state, the inside of the recess 16 becomes a negative pressure, and the ink in the recording head 13 is discharged from the nozzle opening 20 into the recess 16.

Next, the head unit 2 will be described. As shown in FIG. 2, the illustrated head unit 2 includes a resin frame 23, and an ink cartridge 25 is provided on an upper surface of a base plate portion 24 of the frame 23.
A cartridge holder 26 to which the (ink storage unit of the present invention) can be attached is formed.

The ink cartridge 25 is a hollow box-shaped member having an interior partitioned into a plurality of ink chambers. In each ink chamber, ink is stored while being held by an ink absorbing material (not shown). Have been. As shown in FIG. 4, the ink cartridge 25 in the present embodiment includes a black cartridge 25A and a color cartridge 25B. The black cartridge 25A has a single ink chamber 25a for storing black ink. Reference numeral 25B includes three ink chambers 25b, 25c, and 25d for separately storing yellow ink, magenta ink, and cyan ink. Further, at the bottom of each of the ink chambers 25a to 25d, a needle connection portion 29 (2) into which a corresponding ink supply needle 27 (27a to 27d) is inserted.
9a to 29d) are provided. The needle connection part 29 functions as an ink outlet of the ink storage part.

On the other hand, the recording head 13 is mounted on the lower surface of the base plate 24 opposite to the cartridge holder 26 from below. The recording head 13 and each of the ink chambers 25a to 25d are communicated with the corresponding ink supply path (the ink supply needle 27 and the converging flow path section 60, which will be described later), and the four colors stored in the ink cartridge 25. Are supplied to the recording head 13. As shown in FIGS. 5 and 6, the recording head 13
The actuator unit 31 and the flow path unit 32 are formed, and the actuator unit 31 and the flow path unit 32 are integrated in a state of being overlapped. The actuator unit 31 is configured by stacking a pressure chamber plate 33, a pressure chamber substrate 34, and a vibration plate 35, and integrating them by firing or the like. Channel unit 32
Is provided with a supply port plate 36, a reservoir plate 37, and a nozzle plate 15, and is integrally joined by an adhesive film 38 interposed between the plates. Further, the actuator unit 31 and the flow path unit 32 are provided with an adhesive film 39 interposed between the actuator unit 31 and the flow path unit 32.
Are joined together.

The nozzle plate 15 is a thin plate-like member made of a metal material such as stainless steel. A plurality of nozzle openings 20 penetrating in the plate thickness direction are formed in the nozzle plate 15 in rows, and two rows of the nozzle rows are formed side by side. Then, one nozzle row is used as a single nozzle row 41 and the other nozzle row is used as a divided nozzle row 42. The single nozzle row 41 is a nozzle row capable of ejecting the same ink, and includes, for example, 48 nozzle openings 20. In the present embodiment, black ink is ejected from the single nozzle row 41. The divided nozzle row 42 is a nozzle row in which a plurality of nozzle openings 20 are divided into blocks in the nozzle row direction. The divided nozzle row 42 is composed of three nozzle blocks, and one nozzle block includes, for example, 1
It is constituted by five nozzle openings 20. In this embodiment, a yellow block BY that can discharge yellow ink, a magenta block BM that can discharge magenta ink, and a cyan block BC that can discharge cyan ink are used in order from the upper side in FIG.

The reservoir plate 37 is, like the nozzle plate 15, a thin plate-like member made of a metal material such as stainless steel. The reservoir plate 37 has a first reservoir 43 corresponding to the single nozzle row 41 and a second reservoir 4 corresponding to the divided nozzle row 42.
Fourth, a third reservoir 45 and a fourth reservoir 46 are formed. These reservoirs are common ink chambers in the present invention and are constituted by openings penetrating in the thickness direction. The first reservoir 43 functions as a black reservoir for storing black ink. The second reservoir 44 is a cyan reservoir in which cyan ink is stored, and corresponds to the cyan block BC. The third reservoir 45 is a magenta reservoir in which magenta ink is stored, and corresponds to the magenta block BM. The fourth reservoir 46 is a yellow reservoir that stores yellow ink, and corresponds to the yellow block BY. The end of each reservoir extends to one end of the reservoir plate 37 in the nozzle row direction, and the one end communicates with the ink introduction port 47 (47a to 47d, described later). I have. The nozzle opening 2 of the reservoir plate 37
At a position corresponding to 0, a plurality of first nozzle communication ports 50 are provided so as to penetrate in the thickness direction.

The supply port plate 36 is also a thin plate-like member made of a metal material such as stainless steel.
An ink supply port 51 communicating with the reservoirs 43 to 46;
A plurality of nozzle openings 20 are formed at the same pitch, and a plurality of second nozzle communication ports 52 penetrating in the plate thickness direction are formed corresponding to the first nozzle communication ports 50. The ink supply port 51 is a portion that gives fluid resistance (flow resistance) to the ink in the individual ink flow path described later. An ink inlet 47 is provided at one end of the supply port plate 36 in the direction in which the communication ports are arranged. The ink inlet 47 communicates with the outlet of the ink supply path, and functions as an ink inlet for the recording head 13. Four ink inlets 47 are provided in accordance with the types of ink that can be ejected. In other words, in order from the left side of FIG.
a, an ink inlet 47b for cyan ink, an ink inlet 47c for magenta ink, and an ink inlet 47d for yellow ink are opened.

The pressure chamber plate 33 is formed of a ceramic thin plate having a thickness suitable for forming the pressure chamber 54, for example, a thin plate of alumina, zirconia, or the like.
A plurality of openings serving as pressure chambers 54 are formed in a state penetrating in the thickness direction of the plate. This pressure chamber 54
Are elongated holes formed in a row at a constant pitch equal to the pitch of the nozzle openings 20 and elongated in the left-right direction perpendicular to the row direction. In the present embodiment, two rows of the pressure chambers 54 are formed side by side on the left and right, and one pressure chamber row (the pressure chamber row on the right side in the figure) serves as the pressure chamber 54 for the divided nozzle row 42, The pressure chamber row on the other side (the pressure chamber row on the left side in the figure) becomes the pressure chamber 54 for the single nozzle row 41.

The pressure chamber substrate 34 is made of the same ceramic material as the pressure chamber plate 33 and has a third nozzle communication port 55.
And a supply-side communication port 56. The third nozzle communication port 55 is connected to the second nozzle communication port 5.
2 is a hole formed in the thickness direction corresponding to 2,
It communicates with the end of the pressure chamber 54 on the nozzle opening side. The supply-side communication port 56 is a hole formed in the thickness direction corresponding to the ink supply port 51, and communicates with the end of the pressure chamber on the side opposite to the third nozzle communication port 55.

The vibration plate 35 is a thin plate made of a ceramic material having elasticity. Diaphragm 3 opposite to pressure chamber 54
A plurality of piezoelectric vibrators 57 are arranged on the outer surface of the piezoelectric element 5 so as to correspond to the respective pressure chambers 54. The illustrated piezoelectric vibrator 57 is a vibrator in a bending vibration mode, and is bent by a drive signal supplied from a signal supply cable (not shown).
The volume of the pressure chamber 54 is changed.

In the recording head 13 having the above structure,
The ink introduction ports 47a to 47d communicate with the reservoirs 43 to 46, and the reservoirs 43 to 46 communicate with the pressure chambers 54 through the ink supply port 51 and the supply side communication port 56. Further, the pressure chamber 54 and the nozzle opening 20 communicate with each other through the nozzle communication ports 50, 52, and 55. Therefore, a series of head-side ink flow paths from the ink inlet 47 to the nozzle openings 20 through the reservoirs 43 to 46 and the pressure chambers 54 are formed in the recording head 13. Further, a series of individual ink flow paths from the ink supply port 51 to the nozzle opening 20 via the pressure chamber 54 are formed between the reservoirs 43 to 46 and the nozzle opening 20.

Next, an ink supply path communicating between the needle connection portion 29 of each ink chamber and the ink inlet 47 of the recording head 13 will be described. As shown in FIGS. 3 and 4, the ink supply path includes an ink supply needle 27 (27 a to 27 d) inserted into the needle connection portion 29 and an ink supply needle 2
7, and the convergent flow path portion 60 whose outlet communicates with the ink introduction ports 47 (47 a to 47 d) of the recording head 13.
(60a to 60d).

The ink supply needle 27 is a resin member comprising a hollow shaft portion having an inflow hole 61 at a sharp end, and a tapered portion formed by expanding a side wall downwardly from the hollow shaft portion. . A flange is formed at the lower end of the tapered portion, and a filter 62 is provided below the flange.

The convergence flow path section 60 is a flow path that communicates between the ink supply needle 27 and the ink introduction port 47 as described above, and extends downward from the outlet of the ink supply needle 27. The cross section in the width direction is a substantially circular channel. In the present embodiment, the arrangement order of the ink chambers 25a to 25d and the arrangement order of the ink introduction ports 47a to 47d are aligned. That is, in FIG. 4, in order from the left side, an ink chamber 25a and an ink inlet 47a for black ink, an ink chamber 25b and an ink inlet 47b for cyan ink, an ink chamber 25c and an ink inlet 47c for magenta ink.
And an ink chamber 25d for yellow ink and an ink introduction port 47d.

Since the width of the ink cartridge 25 is sufficiently larger than the width of the recording head 13, the interval between the ink supply needles 27 and the pitch of the ink introduction ports 47 are compared. The setting interval is wider. Therefore, each of the converging flow path portions 60a to 60d extends obliquely downward so as to converge on the recording head 13 side. The recording head 13 has an ink supply needle 27b for the cyan ink chamber and an ink supply needle 27c for the magenta ink chamber.
, The distance in the horizontal direction from the ink supply needle 27a for black ink to the ink introduction port 47a, and the distance from the ink supply needle 27d for yellow ink to the ink introduction port 47d. Is the distance from the ink supply needle 27 for cyan ink to the ink introduction port 47 and the ink supply needle 2 for magenta ink.
7 is longer than the distance from the ink inlet 47. Therefore, the lengths of the converging flow paths 60a to 60d are longer for the converging flow path 60a for black ink and the converging flow path 60d for yellow ink, and for the converging flow path 60b for cyan ink and magenta ink. The converging flow path 60c is short.

By the ink supply path and the above-described head-side ink flow path, a series of ink flow paths from the inflow hole 61, which is the entrance of the ink supply path, to the nozzle orifice 20 correspond to the ink type. One is formed.

Incidentally, the flow path resistance (flow resistance) of each ink flow path changes according to the length and cross-sectional area of the ink flow path. Here, the length of the ink flow path is a distance from the inflow hole 61 which is an inlet of the ink supply path to the nozzle opening 20. In the recording head 13 having the plurality of nozzle openings 20 as in this embodiment, the distance from the inflow hole 61 to the center of the nozzle group in the column direction (that is, the average distance) is the length of the ink flow path. For example, regarding the ink flow path for black ink, the 24th nozzle opening 20 and the 25th nozzle opening 2 from the end of the single nozzle row 41
The distance to 0 is the length of the ink flow path. Also,
With respect to the ink flow path for yellow ink, the distance from the end of the nozzle openings 20 forming the yellow block BY to the eighth nozzle opening 20 is the distance of the ink flow path. Similarly, for the ink flow paths for the magenta ink and the cyan ink, the distance from the end to the eighth nozzle opening 20 is the distance of the ink flow path.

The length of the head-side ink flow path from the ink introduction port 47 to the end of the ink flow path is the longest for the yellow ink flow path, and the second for the black ink and magenta ink flow paths. It is long and the length of the cyan ink channel is the shortest. Therefore, when viewed as a whole of the ink flow path, the ink flow path for yellow ink is the longest, and the ink flow path for black ink is the second longest. The ink flow path for the cyan ink and the ink flow path for the magenta ink are the shortest and have substantially the same length.

Here, if the inner diameters of the ink supply paths are made uniform in all the ink flow paths, the flow path resistance of the ink flow paths is substantially determined by the length of the ink flow paths. The flow path resistance is larger than a short ink flow path. As a result, when the ink in the recording head 13 is forcibly discharged by the recovery mechanism (the cap member 14 and the suction pump 18), the amount of discharged ink varies for each type of ink. That is, the discharge amount from the ink flow path having a small flow path resistance is larger than the discharge amount from the ink flow path having a large flow path resistance. Therefore, the discharge amount of the magenta ink and the cyan ink is larger than the discharge amount of the black ink and the yellow ink.

In view of this point, in the present embodiment, the cross-sectional area in the width direction of the ink supply path is changed according to the length of the ink flow path. That is, the longer the length of the ink flow path, the larger the cross-sectional area of the ink supply path in the width direction. In particular,
Regarding the ink flow paths for the black ink and the yellow ink, the diameters of the converging flow paths 60a and 60d are 1.4 mm.
I have to. The diameters of the converging flow paths 60b and 60c are set to 1.2 mm for the ink flow paths for the magenta ink and the cyan ink. Note that this numerical value is merely an example, and the present invention is not limited to this. For example, the diameter of the converging flow path 60d for yellow ink is set to 1.
4 mm, the diameter of the converging flow channel portion 60a for black ink is 1.3 mm, and the converging flow channel portions 60b and 60c for magenta ink and cyan ink are 1.2 mm. A unit 60 may be provided.

As described above, by changing the diameter of the converging flow path portions 60a to 60d according to the length of the ink flow paths, the flow path resistance of the ink flow paths having different lengths can be made uniform. Accordingly, even if the ink in each ink flow path is collectively suctioned under the same conditions by the above-described recovery mechanism, the amount of ink discharged from each ink flow path can be made uniform. Therefore, at the time of the recovery operation, it is possible to discharge a sufficient amount of ink necessary for the function recovery from each ink flow path, and it is possible to prevent a problem that the ink is wasted. As a result, the ink stored in the ink cartridge 25 can be efficiently used for recording characters and images, and the frequency of cartridge replacement can be reduced.

Incidentally, the flow path resistance in the ink flow path also changes depending on the number of individual ink flow paths from the reservoirs 43 to 46 to the nozzle openings 20, that is, the number of nozzle openings 20 communicating with the reservoir.

That is, the flow path resistance Rt of the ink flow path can be expressed by the following equation (1).

Rt = (Rn + Rc) / N + Rp (1) where Rn: resistance of the nozzle opening 20, Rc: pressure chamber 5
4, resistance Rp: flow path resistance, N: number of nozzles

According to the equation (1), the reservoirs 43 to 46
It can be seen that the greater the number of nozzle openings 20 (individual ink channels) communicating with the nozzles, the lower the channel resistance. Therefore, when the ink is discharged from the plurality of ink flow paths by the above recovery mechanism, under the conditions that the applied pressure is constant, the viscosity of the ink is constant, and the flow path resistance of the individual ink flow path is constant, Is proportional to the number of nozzle openings 20 communicating with the reservoir.

The single nozzle row 41 for discharging black ink is constituted by 48 nozzle openings 20. Each of the yellow, magenta and cyan nozzle blocks is constituted by 15 nozzle openings 20. ing. Accordingly, the flow path resistance Rtb in the ink flow path for black ink can be expressed by the following equation (2), and the flow path resistance Rtc per color in the yellow, magenta, and cyan color inks is expressed by the following equation (3). Can be represented.

Rtb = (Rn + Rc) / 48 + Rpb (2) Rtc = (Rn + Rc) / 15 + Rpc (3) where Rpb is the resistance of the flow path for black ink, Rp
c: resistance of the flow path for the color ink

By determining the flow path resistance for the black ink and the flow path resistance for each color ink such that the relationship of Rtb = Rtc is established, the amount of ink discharged during the operation of the recovery mechanism can be reduced. Can be aligned at a high level. That is, the diameters of the converging flow path portions 60a to 60d determined based on the lengths of the ink flow paths are set to the respective reservoirs 43 to
By determining the number of the nozzle openings 20 communicating with 46 in consideration of the number, the discharge amounts of the respective inks can be aligned with high accuracy. For example, with respect to the color ink flow path having a small number of communicating nozzle openings 20, the converging flow path sections 60b to 60b
The correction is made in the direction of increasing the diameter of 0d, and the ink flow path for black ink having a large number of communicating nozzle openings 20 is corrected in the direction of reducing the diameter of the converging flow path section 60a.

By the way, in the first embodiment described above, the head unit 2 having the converging flow path portion 60 inclined obliquely downward from the ink supply needle 27 to the ink introduction port 47 is exemplified. It is not limited to the configuration. For example, the converging flow path may be formed in a plate-shaped member. Hereinafter, a second embodiment configured as described above will be described.

As shown in FIG. 7, the head unit 70
Is a frame 71 provided at the uppermost portion, and a plate-shaped converging flow path substrate 72 joined to the lower surface of the frame 71.
, A plate-shaped filter portion 73 joined to the lower surface of the converging flow path substrate 72, and a recording head 74 disposed on the lower surface side of the filter portion 73.

On the upper surface of the base plate portion 75 of the frame 71, six bottomed ring-shaped pedestals 77 for joining ink supply needles 76 (corresponding to the entrance side connection portion of the present invention) are formed. A through hole 78 is formed at the center of the base 77 so as to penetrate the base plate 75 in the thickness direction. The converging flow path substrate 72 is a resin plate material in which a plurality of converging flow path portions 79 are formed. The converging flow path portion 79 is a groove having a bottom with an open upper surface, and is formed in a number corresponding to the type of ink stored in the ink cartridge 25. In the present embodiment, six converging flow passage portions 79... Corresponding to the six types of inks are formed above the ink inlets 81. Is formed in a straight line up to the outlet side end located at. A through hole (not shown) is formed at the outlet end of each of the converging flow paths 79.

The filter portion 73 is a member provided between the head case of the recording head 74 and the converging flow path substrate 72, and includes a filter mounting plate 82 made of synthetic resin and a filter formed by a fine mesh. 83. The filter mounting plate 82 is provided with six filter mounting holes corresponding to the ink types, penetrating in the plate thickness direction. The filter mounting hole is a portion where the filter 83 is mounted, and constitutes a part of a series of ink supply paths leading to the ink inlet 81.

These frames 71 (base plate portion 7)
5) The converging flow path substrate 72 and the filter unit 73 are joined in a stacked state, and in this joined state, the ink supply needle 7
A plurality of ink supply paths corresponding to the types of ink are formed from a series of ink supply paths 6 to the ink introduction port 81 of the recording head 74 through the focusing channel and the filter 83 in order.

In this embodiment, with respect to the converging flow path portion 79 which is a part of the ink supply path, the longer the ink flow path from the inflow hole 84 of the ink supply needle 76 to the nozzle opening, the longer the flow path. The cross-sectional area of the converging channel portion 79 is increased by increasing the width. With this configuration, the first
As in the embodiment, the fluid resistance between the ink flow paths having different lengths can be made uniform. Accordingly, even if the ink in each ink flow path is collectively suctioned under the same conditions by the above-described recovery mechanism (cap member 14, suction pump 18, see FIG. 3), the ink is discharged from each ink flow path. The amount of ink used can be made uniform. Therefore, during the recovery operation,
It is possible to discharge a sufficient amount of ink necessary for the function recovery from each ink flow path, and it is possible to prevent a problem that the ink is wastefully consumed. Further, in the present embodiment, the converging flow path portion 79 is connected to the converging flow path substrate 7 of the plate-like member.
2, the converging flow path 79 having a desired width can be easily formed. For this reason, the flow path resistance of the ink flow path can be determined with high accuracy, and the manufacturing is easy.

The present invention is not limited to the above embodiments, and various modifications can be made based on the claims. For example, the present invention may be applied to a recording head using a piezoelectric vibrator in a longitudinal vibration mode. Similarly, the present invention may be applied to a recording head that generates bubbles by generating heat from a heating element and discharges ink droplets by the bubbles.

[0048]

According to the present invention as described above, the following effects can be obtained. That is, a plurality of series of ink flow paths from the inlet of the ink supply path connected to the ink storage section to the nozzle opening are provided in accordance with the type of ink, and the cross-sectional area of the ink supply path in the width direction is determined by the ink flow path. Is determined according to the length of the ink flow path, and the fluid resistance of each ink flow path is equalized. Therefore, even if the ink in each ink flow path is collectively suctioned under the same conditions, the ink discharged from each ink flow path Can be equalized. Therefore, at the time of the recovery operation, it is possible to discharge a sufficient amount of ink necessary for the function recovery from each ink flow path, and it is possible to prevent a problem that the ink is wasted. As a result, the ink stored in the ink storage unit can be used more for recording characters and images.

The ink supply path includes an inlet-side connecting part connected to the ink storage part, and a converging flow path part communicating with the downstream side of the inlet-side connecting part and converging toward the recording head. In a case where the converging flow path is formed in a plate-like member, a converging flow path having a desired width can be easily formed. For this reason, the flow path resistance of the ink flow path can be determined with high accuracy, and the production efficiency can be improved.

The sectional area of the ink supply path in the width direction is
When the number of nozzle openings communicating with the common ink chamber is determined in consideration of the number of nozzle openings, the amount of ink discharged from each ink flow path can be aligned with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the structure of an ink jet printer.

FIG. 2 is a perspective view of the recording head unit as viewed from the recording head side.

FIG. 3 is a cross-sectional view of the head unit on which the ink cartridge is mounted, which is cut in the front-rear direction.

FIG. 4 is a cross-sectional view of the ink cartridge and the head unit cut in the left-right direction.

FIG. 5 is a plan view of a recording head.

6 is a sectional view taken along line AA of FIG.

FIG. 7 is an exploded perspective view illustrating a head unit according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink-jet printer 2 Recording head unit 3 Carriage 4 Housing 5 Guide member 6 Pulse motor 7 Drive pulley 8 Idle pulley 9 Timing belt 10 Paper feed motor 11 Paper feed roller 12 Recording paper 13 Recording head 14 Cap member 15 Nozzle plate 16 Depressed portion of cap member 17 Ink discharge path 18 Suction pump 19 Moisturizer 23 Frame 24 Base plate 25 Ink cartridge 26 Cartridge holder 27 Ink supply needle 29 Needle connection 31 Actuator unit 32 Flow path unit 33 Pressure chamber plate 34 Pressure chamber Substrate 35 Vibration plate 36 Supply port plate 37 Reservoir plate 38 Adhesive film 39 Adhesive film 41 Single nozzle row 42 Split nozzle row 43 First reservoir (black reservoir) 4 2nd reservoir (cyan reservoir) 45 3rd reservoir (magenta reservoir) 46 4th reservoir (yellow reservoir) 47 ink introduction port 50 first nozzle communication port 51 ink supply port 52 second nozzle communication port 54 pressure chamber 55 third nozzle Communication port 56 Supply-side communication port 57 Piezoelectric vibrator 60 Convergent flow path section 61 Inlet hole for ink supply needle 62 Filter 70 Recording head unit 71 Frame 72 Convergent flow path substrate 73 Filter section 74 Recording head 75 Base plate section 76 Ink supply needle 77 Pedestal 78 Through-hole 79 Converging flow path 81 Ink inlet 82 Filter mounting plate 83 Filter 84 Inflow hole of ink supply needle

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Katakura 3-3-5 Yamato, Suwa-shi, Nagano F-term in Seiko Epson Corporation (reference) 2C056 EA25 EA27 JA13 JA17 JC20 KB13 KC05 KC13 KC22

Claims (4)

[Claims] 1. An ink supply path communicating from an ink outlet of an ink storage section to an ink inlet of a print head, and a plurality of types of ink individually stored in the ink storage section are supplied to the print head through the ink supply path. In a recording head unit configured to supply and discharge from a nozzle opening formed on a nozzle surface, a series of ink flow paths from an inlet of an ink supply path connected to an ink storage unit to the nozzle opening are formed by a type of ink. A recording head unit, wherein a plurality of ink supply paths are provided, and the cross-sectional area of the ink supply path is increased as the length of the ink flow path is increased, and the fluid resistance of each ink flow path is made uniform. 2. An ink supply path comprising: an inlet-side connection portion connected to an ink storage portion; and a converging flow passage portion communicating with the downstream side of the inlet-side connection portion and converging toward the recording head. The recording head unit according to claim 1, wherein the converging flow path portion is formed in a plate-shaped member. 3. The recording head according to claim 1, wherein said recording head includes a common ink chamber for storing ink from an ink supply path, and a plurality of individual inks communicating between said common ink chamber and a nozzle opening. 3. The recording head unit according to claim 1, further comprising a flow path, wherein a cross-sectional area of the ink supply path increases as the number of nozzle openings communicating with the common ink chamber decreases. 4. 4. A recovery mechanism for discharging ink from the recording head unit according to claim 1, wherein the closing member includes a negative-pressure air portion, and a suction mechanism that communicates with the negative-pressure air portion. With the nozzle opening facing the negative pressure air space, the nozzle surface is sealed with a blocking member, and the suction mechanism is operated to make the inside of the negative pressure air space a negative pressure and collectively suction the ink in the plurality of ink flow paths. A recovery mechanism for the recording head unit.