JP2000015811A - Liquid discharge recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain an adhesion between a liquid discharge part and a discharge pressure formation substrate well by urging a liquid discharge opening formation member towards a coupling member. SOLUTION: Both end parts of a leaf spring member 60 are adapted to shift in a direction nearly orthogonal to an arrangement direction of ink discharge openings 64a and held in touch with an inner peripheral face of a recessed part 58. The leaf spring member 60 is therefore pressed into the recessed part 58 and fixed with an elastic force. An urging force along the direction nearly orthogonal to the arrangement direction of the ink discharge openings 64a at the leaf spring member 60 acts in a direction to expand an interval between an ink discharge part 52A and an ink discharge part 52B. A diaphragm partitioning an ink branch passage of each of the ink discharge parts 52A and 52B and a peripheral edge part of a common liquid chamber are pressed towards a heater board 66A by the urging force of the leaf spring member 60. Even when a partition wall warps, a favorable adhesion is obtained between the diaphragm partitioning the ink branch passage and peripheral edge part of the common liquid chamber, and the heater board 66A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid discharge recording head which performs a recording operation by discharging a liquid onto a recording surface of a recording medium.

[0002]

2. Description of the Related Art An ink jet recording apparatus generally has an ink jet recording head as a liquid discharge recording head. The inkjet recording head performs a recording operation by discharging ink onto a recording surface of a recording medium.

For example, as shown in FIG. 6, there has been known an ink jet recording head having ink ejection portions 8A and 8B for ejecting inks having different densities, respectively, due to a demand for high image quality and high speed printing.

In FIG. 6, an ink jet recording head includes a base 2 fixed to the bottom of an ink tank holder TKH connected to an ink tank (not shown).
And ink ejection portions 8A and 8B respectively formed integrally with the base portion 2 so as to protrude from the bottom portion of the ink tank holder TKH and having ink ejection port forming portions 14 for ejecting ink, and the ink ejection portions 8A and 8B Discharge unit 8B
And leaf spring members 6A and 6B as connecting members for connecting a heater board 4a to be described later as a discharge pressure forming substrate, and one end of which is electrically connected to the heater boat 4a, and supplies a drive control signal group supplied by ink. A printed wiring board 4A to be supplied to the heater boat 4a on the discharge unit 8A side,
One end is electrically connected to the heater boat 4a, and includes a printed wiring board 4B for supplying a supplied drive control signal group to the heater boat 4a on the ink ejection section 8B side.

[0005] A so-called top plate of an ink jet recording head is formed by integrally molding the base portion 2 and the ink discharge portions 8A and 8B. A concave portion 10 is provided between the ink ejection portions 8A and 8B arranged substantially in parallel with each other so as to prevent the inks from being mixed during ink ejection. A plurality of ribs 12 are formed in the concave portion 10 so as to connect the ink discharge portions 8A and 8B.

Since the ink discharge units 8A and 8B have the same structure, only the ink discharge unit 8A will be described, and the description of the ink discharge unit 8B will be omitted.

[0007] In the ink discharge section 8A, an ink discharge port forming section 14 is formed on the upper surface along the longitudinal direction. In the ink discharge port forming section 14, a plurality of ink discharge ports 14a are formed at predetermined intervals, and each of the ink discharge ports 14a of the ink discharge port forming section 14 has a structure shown in FIG.
(A), it communicates with a plurality of ink branch channels 16a provided on the end face side facing the heater board 4a. Adjacent ink branch channels 16a are separated by each partition 16b. Each ink branch channel 16a
Is a common liquid chamber 1 in which ink is stored, for example.
8A and 18B. Also, the common liquid chamber 18
A and the common liquid chamber 18B are separated by a partition wall 20. As shown in FIG. 7B, the common liquid chamber 18A and the common liquid chamber 18B
a communicates with an ink tank (not shown).

On the surface of the heater board 4a facing each of the ink branch channels 16a, a heater as an electrothermal converter is provided correspondingly. Each heater is controlled based on a drive control signal group supplied through the printed wiring board 4A. By controlling the driving of each heater, the ink stored in each of the common liquid chambers 18A and 18B is supplied to each ink branch flow path 16a in the direction indicated by the arrow in FIG. The ink introduced into the flow path 16a is heated, and is
The ink droplet ID is ejected from a.

At this time, the ink board 16a and the common liquid chambers 18A and 18B are connected to the heater board 4a by the urging force of the pressing portion 6a of the leaf spring member 6A, as shown in FIG. 7B. By being pressed toward the respective ink branch channels 16a and bringing the surfaces into close contact with each other, the ink is sealed.

Therefore, the surfaces of the partition 16b and the partition wall 20 that are in contact with the heater board 4a are required to have a relatively high degree of flatness.

[0011]

However, when the ink discharge portions 8A and 8B are formed of a resin material by injection molding, the dimensional difference is caused by the thickness of the portion where the common liquid chambers 18A and 18B are formed and the partition wall 20. In the vicinity of the partition wall 20, warpage of about several μm may be generated toward the heater board 4 a side due to the presence of the gap between the wall and the wall of the heater board 4 a.

When the vicinity of the partition wall 20 is warped as described above,
The adhesion between the partition 16b and the partition wall 20 and the heater board 4a is deteriorated, which causes uneven printing.

In such a case, it is conceivable that the urging force of the pressing portion 6a of the leaf spring member 6A is increased to forcibly bring the partition 16b and the partition wall 20 into close contact with the heater board 4a. There is a possibility that the ink ejection portions 8A and 8B may be bowed in a bow due to the increase in the height. That is, since the mutual interval between the ink ejection ports is different between the both end portions and the central portion, the position of the ink ejection ports is shifted from a predetermined reference position.

In view of the above problems, the present invention relates to a liquid discharge recording head which performs a recording operation by discharging a liquid to a recording surface of a recording medium, wherein a heater board is brought into close contact with a liquid discharging portion. Provided is a liquid discharge recording head that can maintain good adhesion between a liquid discharge portion and a discharge pressure forming substrate without increasing the urging force of a coupling member even when the liquid discharge recording head is formed in a warped state. The purpose is to:

[0015]

In order to achieve the above object, a liquid discharge recording head according to the present invention comprises a liquid discharge port forming member having an arrangement of a plurality of liquid discharge ports, a liquid discharge port forming member, A discharge pressure forming substrate for forming a liquid flow path in close contact with each of the plurality of liquid discharge ports and discharging the liquid supplied to the liquid flow path through the plurality of liquid discharge ports; A connecting member for pressing the member against the member and connecting the discharge pressure forming substrate to the liquid discharge port forming member; A biasing member for biasing the outlet forming member toward the coupling member.

[0016]

FIG. 4 shows the appearance of an example of a liquid discharge recording head according to the present invention, together with an ink jet recording apparatus to which it is applied.

The ink jet recording apparatus shown in FIG. 4 has two ink tank holders 4 detachably mounted.
6, a carriage member 32 supporting each of the
And a guide shaft 30 supported at both ends of the carriage member 32 for reciprocatingly supporting the bottom of the carriage member 32, and reciprocating on the bottom of the carriage member 32 supported on both ends of the housing 28 substantially parallel to the guide shaft 30. Guide shaft 31 for supporting and carriage member 3
A motor 40 for transmitting a driving force to a belt 36 connected to the belt 2 via a pulley 38B, and a recovery process for ink ejection units 52A and 52B, which will be described later, are provided at one end inside the housing 28. And a recovery processing device 42 to be performed.

The belt 36 is attached to the housing 2 at a predetermined interval.
Pulleys 38 rotatably supported on the back surface of the pulley 8
A and 38B. The pulley 38B is connected to an output shaft of the motor 40. The motor 40 is controlled based on a drive control signal from a control unit (not shown), and its output shaft is rotated in the forward or reverse direction. As a result, the carriage member 32 reciprocates within a predetermined distance from a position directly above the recovery processing device 42 while being guided by the guide shafts 30 and 31 at a predetermined timing with the two ink tank holders 46. I'm sullen.

A connector of the carriage member 32 is electrically connected to one end of a flexible cable 34 for supplying a drive control signal group to a recording head unit described later.

In addition, a sheet P as a recording medium is provided inside the housing 28 on the side of the recovery processing device 42.
A sheet conveyance path for intermittently conveying a in the direction indicated by arrow F in FIG. 4 is provided below the carriage member 32.

A color ink tank 44 and a black ink tank 48 are mounted on the two ink tank holders 46, respectively. Color ink tank 4
4 and the black ink tank 48 are respectively
The color ink tank 44 has the same structure except for the color of the stored ink. Therefore, the color ink tank 44 will be described, and the description of the black ink tank 48 will be omitted.

The inside of the color ink tank 44 is a so-called
A room in which dark yellow ink, dark magenta ink, and dark cyan ink having a predetermined relatively high density are stored, respectively, and light yellow ink and light yellow having a relatively low density compared to the density of the dark yellow ink The magenta ink and the light cyan ink are each divided into six rooms where they are stored. Each room is provided with urethane foam as an ink absorber. As shown in FIG. 5, an ink supply port 44 communicating with each room is provided.
Y, 44M, and 44C are respectively formed corresponding to ink flow paths 46Y to 46C of an ink tank holder 46 described later.

Each ink tank holder 4 made of resin
6 has a tank accommodating portion 46A for detachably accommodating the black ink tank 48 or the color ink tank 44, respectively. In the tank accommodating portion 46A, ink flow paths 46Y, 46M, and 46, which respectively supply ink of each color or black ink to ink supply passages 52ar in ink ejection portions 52A and 52B described later.
C is provided inside. Ink flow paths 46Y to 46C
Are the respective ink supply paths 5 of the ink ejection section 52A.
It communicates with 2ar.

Although not shown in FIG. 5, each ink supply path 52ar of the ink discharge section 52B is not shown.
The ink flow path communicating with is also formed in the same manner.

The portion of the ink tank holder 46 where the ink flow paths 46Y to 46C are formed corresponds to the ink flow path 46
The ink flowing through Y, 46M, and 46C is formed of a highly transparent material so that the ink can be viewed from the outside.

As shown in FIG. 5, each of the two ink tank holders 46 is provided with ink ejection portions 52A and 52B on a base 50 at the bottom facing the paper Pa. When the paper Pa is stopped, the ink ejecting units 52A and 52B eject ink to the recording surface of the paper Pa through the opening 28a of the housing 28 with the movement of the carriage member 32 to perform a recording operation.

The recording head unit including the ink ejection sections 52A and 52B is, for example, of a bubble jet type, and is fixed to the outer peripheral surface at the bottom of the ink tank holder 46 as shown in FIGS. Base part 5 molded of resin integrally with ejection parts 52A and 52B
0 and each common liquid chamber 5 of the ink ejection sections 52A and 52B.
2as and each ink flow path are formed by closely adhering the ink ejection sections 52A and 52B to each other, and a heater board 66A is provided at one end.
Printed circuit boards 54A and 54B electrically connected to ink discharge sections 52A and 52B, respectively, and heater boards 66A and 66B respectively.
Of each common liquid chamber 52as and each ink flow path,
Heater boards 66A and 66B and ink ejection section 52A
Spring members 56A and 56B as coupling members for coupling the ink ejection portions 52A and 52B, and a leaf spring member 60 as an urging member press-fitted into a concave portion 58 formed between the ink ejection portions 52A and 52B. It is comprised including.

The leaf spring members 56A and 56B are opposed to both side surfaces of the ink ejection portions 52A and 52B, respectively, and a pair of engaging portions 56ak engaged with a pair of engaged portions 52a and 52b, respectively. And 56b
k.

The engaging portion 56ak of the leaf spring member 56A is formed on a side surface portion bent in the left and right direction so as to be continuous with a base end surface portion 56as abutting on the outer peripheral portion of the ink discharge port forming portion 64A of the ink discharge portion 52A. Have been. Also,
As shown in FIG. 2, the pressing surface portion 56ap that presses the heater board 66A toward the ink ejection portion 52A is formed to be curved toward the printed wiring board 54A so as to be continuous with the base end surface portion 56as.

The engaging portion 56bk of the leaf spring member 56B is formed on a side surface portion bent in the left and right direction so as to be continuous with a base end surface portion 56bs abutting on the outer peripheral portion of the ink discharge port forming portion 64B of the ink discharge portion 52B. Have been. Also,
The pressing surface portion 56bp that presses the heater board 66B toward the ink ejection portion 52B is formed to be continuous with the base end surface portion 56bs and curved toward the printed wiring board 54B.

Each of the heater boards 66A and 66B has a plurality of heaters as electrothermal converters arranged in a straight line at predetermined intervals.

Printed circuit boards 54A and 54 having one ends connected to heater boards 66A and 66B, respectively.
B are electrically connected to the heater boards 66A and 66B, respectively, by a tape carrier system (TAB).

Thus, drive control signals supplied through the connector of the carriage member 32 and the connector of the ink tank holder 46 are supplied to the heaters of the heater boards 66A and 66B via the printed wiring boards 54A and 54B, respectively. It will be.

The base unit 50 and the ink ejection units 52A and 52
2B is integrally molded with, for example, polysulfone to form a so-called top plate of a recording head unit.

An ink discharge port 52A and an ink discharge port 52B, which are arranged so that an ink discharge port forming section 64A and an ink discharge port forming section 64B, which will be described later, are substantially parallel to each other, are connected to each other when ink is discharged. A concave portion 58 is provided in order to block the ink from mixing. A pair of ribs 62 are formed in the concave portion 58 so as to connect the ink ejection portion 52A and the ink ejection portion 52B.

Since the ink discharging units 52A and 52B have the same structure, only the ink discharging unit 52A will be described, and the description of the ink discharging unit 52B will be omitted. The ink ejection section 52A ejects ink having a density lower than that of the ink ejected from the ink ejection section 52B.

As shown in FIG. 1, the ink discharge section 52A has an ink discharge port forming section 64A in which a plurality of ink discharge ports 64a are formed at predetermined intervals along the transport direction of the paper Pa. Along the upper surface. Each ink ejection port 64a of the ink ejection port forming unit 64A
Are respectively similar to the case shown in FIG.
It communicates with each ink branch channel provided on the end face side of the heater board 66A facing each heater. Adjacent ink branch channels are isolated by each partition. Each of the ink branch channels communicates with, for example, each of the common liquid chambers 52as in which each color of ink is stored. The common liquid chambers 52as are separated from each other by partition walls. At that time, each ink branch flow path and each common liquid chamber 50as
By the urging force of the pressing surface portion 56ap of the leaf spring member 56A, the heater board 66A is pressed toward the respective ink branch flow paths, and the surfaces thereof are brought into close contact with each other, whereby the heater board 66A is sealed. The contact surface between the heater board 66A and the periphery of each common liquid chamber 52as and each partition is:
It is sealed by a sealing material not shown.

As shown in FIG. 2, the common liquid chambers 52as are respectively connected to the ink supply ports 44C to 44C of the color ink tank 44 through the respective ink supply paths 52ar.
4Y.

Therefore, when each ink stored in each common liquid chamber 52as is supplied to each ink branch flow path, when each heater of the heater board 66A is driven and controlled, it is introduced into the ink branch flow path. The ink is heated, and the ink is ejected from the ink ejection port 64a as an ink droplet onto the recording surface of the paper Pa.

Further, the leaf spring member 60 press-fitted into the recess 58 is made of, for example, a relatively thin stainless steel plate.
It is bent and formed to have a curved, for example, V-shaped cross section toward two sides. In the leaf spring member 60, both end portions connected to the bent portion can be displaced in a direction substantially orthogonal to the arrangement direction of the ink ejection ports 64a,
It is in contact with the inner peripheral surface of the recess 58. Therefore, the leaf spring member 60 is pressed into the recess 58 and is fixed by the elastic force. Thereby, the urging force along the direction substantially perpendicular to the direction in which the ink ejection ports 64a are arranged in the leaf spring member 60 is applied to the ink ejection section 52A and the ink ejection section 52.
B is acted in a direction to increase the distance from B.

The order of assembling the leaf spring members 60 is as follows.
Heater boards 66A and 66B and ink ejection section 52A
And before and after the connection work with each partition of 52B and 52B.

The length of the plate spring member 60 in the longitudinal direction is set to be longer than, for example, the length of the ink discharge port forming portion 64A along the direction in which the ink discharge ports are arranged. When the undesired warpage of the partition wall between the common liquid chambers 52as is limited to a part of the ink discharge port forming portion 64A, the length of the leaf spring member 60 may be reduced. The length in the direction may be set to a length corresponding to a part of the region. Further, the cross-sectional shape of the leaf spring member 60 as the elastic member is not limited to the V-shape, and may be formed in a U-shape. Further, the material of the elastic leaf spring member 60 is as follows.
The material is not limited to a stainless steel plate, and may be, for example, an elastomer.

Accordingly, the ink discharge units 52A and 52B
The partition walls partitioning the respective ink branch flow paths and the peripheral portion of the common liquid chamber are pressed toward the heater board 66A by the urging force of the leaf spring member 60, so that the partition wall between the common liquid chambers 52as is undesired. Even if a warp occurs,
Good adhesion between the partition walls separating the ink branch flow paths and the peripheral portion of the common liquid chamber and the heater board 66A can be obtained without increasing the elastic coefficients of the leaf spring members 56A and 56B.

In the above-described example, the recording head unit ejects ink. However, the present invention is not limited to this example. For example, the recording head unit ejects a so-called processing liquid that insolubilizes a predetermined ink dye. May be used.

[0045]

As is apparent from the above description, according to the liquid discharge recording head of the present invention, the connecting member
With the ejection pressure forming substrate coupled to the liquid ejection port forming member, the urging member is additionally disposed to face the coupling member with the arrangement of the plurality of liquid ejection ports of the liquid ejection port forming member interposed therebetween. Since the liquid discharge port forming member is urged toward the connecting member, even when the liquid discharge portion is formed in a state where the portion where the heater board is in close contact with the liquid discharge portion is warped, the liquid discharging portion does not increase the urging force of the connecting member. And good contact with the discharge pressure forming substrate can be maintained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an example of a liquid discharge recording head according to the present invention.

FIG. 2 is a partial sectional view of the example shown in FIG.

FIG. 3 is an exploded perspective view showing components of an example of a liquid discharge recording head according to the present invention in an exploded manner.

FIG. 4 is a perspective view schematically showing an external appearance of an example of a liquid ejection recording head according to the present invention, together with a recording apparatus to which the liquid ejection recording head is applied.

FIG. 5 is a perspective view showing an external appearance of an example of a liquid discharge recording head according to the present invention, together with an ink tank to which the head is applied.

FIG. 6 is a perspective view showing a main part of a conventional liquid discharge recording head.

7A is a partial perspective view showing each common liquid chamber in the example shown in FIG. 6, and FIG. 7B is a partial cross-sectional view in the example shown in FIG.

[Explanation of symbols]

 44 color ink tank 46 black ink tank 52A, 52B ink discharge section 56A, 56B, 60 leaf spring member 58 recess 64A, 64B ink discharge port forming section 66A heater board

Claims (10)

[Claims] A liquid discharge port forming member having an arrangement of a plurality of liquid discharge ports; a liquid flow path communicating with each of the plurality of liquid discharge ports in close contact with the liquid discharge port forming member; A discharge pressure forming substrate for discharging the liquid supplied to the passage through the plurality of liquid discharge ports; and pressing the discharge pressure forming substrate against the liquid discharge port forming member to press the discharge pressure forming substrate to the liquid discharge port. A coupling member coupled to the forming member; and a liquid ejection port forming member disposed opposite to the coupling member with the arrangement of the plurality of liquid ejection ports of the liquid ejection port forming member interposed therebetween and urging the liquid ejection port forming member toward the coupling member. And a biasing member. 2. A first liquid discharge port forming member having an arrangement of a plurality of liquid discharge ports, and a first liquid discharge port forming member having an arrangement of a plurality of liquid discharge ports is disposed so as to face the first liquid discharge port forming member. A second liquid discharge port forming member, and a liquid flow path communicating with each of the plurality of liquid discharge ports, respectively, in close contact with the first liquid discharge port forming member and the second liquid discharge port forming member. A discharge pressure forming substrate for discharging the liquid supplied to the liquid flow path through the plurality of liquid discharge ports, and the discharge pressure forming substrate to the first liquid discharge port forming member and the second liquid discharge port forming member. A coupling member that presses against each of the first and second liquid ejection port forming members to couple the ejection pressure forming substrate to the first liquid ejection port forming member and the second liquid ejection port forming member; The arrangement of the discharge ports and the second An urging member disposed between the body ejection port forming member and the arrangement of the plurality of liquid ejection ports to urge the first liquid ejection port forming member and the second liquid ejection port forming member toward the coupling member; And a member. 3. The liquid discharge recording head according to claim 1, wherein the coupling member is a leaf spring member. 4. The liquid discharge recording head according to claim 1, wherein the urging member is an elastic member. 5. The liquid discharge recording head according to claim 4, wherein said elastic member has a curved cross-sectional shape. 6. The liquid discharge recording head according to claim 4, wherein the length of the elastic member is set longer than the length of the arrangement of the plurality of liquid discharge ports. 7. The liquid discharge recording head according to claim 1, wherein the discharge pressure forming substrate discharges the ink supplied to the ink flow path through the plurality of ink discharge ports. 8. The liquid discharge recording head according to claim 1, wherein the liquid discharge port forming member is formed integrally with a liquid storing portion. 9. The density of the liquid discharged from the plurality of liquid discharge ports of the first liquid discharge port forming member is the concentration of the liquid discharged from the plurality of liquid discharge ports of the second liquid discharge port forming member. 3. The liquid discharge recording head according to claim 2, wherein the density is different from the density. 10. The liquid discharge recording head according to claim 1, wherein the discharge pressure forming substrate has an electrothermal transducer corresponding to each of the plurality of liquid discharge ports.