JP2000040865A - Flexible board bending method and bending device, and liquid injection recording head incorporating flexible board with heater board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable bending of a flexible board to a required angle or shape without causing defects such as cracks of the board, copper foil, etc. SOLUTION: A flexible board (TAB film) 1 comprising a base material such as a polyimide resin, etc., copper foil and resist material having a glass transition point as cover coat material is fixed after fixing means 110 positions one end thereof. The flexible board 1 is adhesively rolled on to a rod 102 disposed at a bending position on the base material side by a pressure roller 122 of rotary bending means 120. The resist material surface of the adhesive rolled flexible board 1 is heated for a certain period of time by a heater block 131 controlled to a predetermined temperature below the glass transition point of the resist material. Consequently, occurrence of cracks, etc., is minimized while the flexible board l can be bent to a predetermined angle at a predetermined position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending method and a bending apparatus for forming and processing a flexible substrate used as an electric circuit board, and a flexible substrate with a heater board bent by the bending method. The present invention relates to a liquid jet recording head.

[0002]

2. Description of the Related Art Conventionally, in a liquid jet recording head such as a bubble jet printer and an ink jet printer,
As described in Japanese Patent Application Laid-Open No. 5-138887, a plurality of electrothermal transducers (heaters) as ejection energy generating elements for generating ink ejection energy and a drive circuit for driving these electrothermal transducers are provided. A heater board, which is a bare chip IC formed, is joined to a grooved top plate having a plurality of ejection holes and ink channels, and a signal corresponding to an image signal input from the outside is converted to an electrothermal conversion element ( An electric wiring board for applying a voltage to the heater is connected to a heater board which is a bare chip IC,
As the electric wiring board, an electric wiring PCB board made of glass epoxy is used.

As a method of manufacturing this type of liquid jet recording head, an electric wiring PCB substrate is bonded on an aluminum plate, and in the next step, a heater board as a bare chip IC is die-bonded to the same surface of the aluminum plate. The PCB board and the electric terminals of the heater board are connected and wired by wire bonding. After that, the ejection holes of the top plate are aligned with the positions of the electrothermal transducers (heaters) on the heater board with high accuracy, and then the top plate is attached. It was fixed and manufactured.

However, when using a PCB board,
It is difficult to reduce the size and density of products such as liquid jet recording heads, and furthermore, expensive equipment such as high-precision die bonding and wire bonding is required in the final assembly device with a slow production cycle.

In recent years, TAB mounting has been used as a means for connecting a bare chip IC to an external device. According to this TAB mounting, a device such as a wire bonding is not required, and an expensive TAB mounting device can be separated from a final assembly line with a slow production tact, so that TAB mounting can be performed at a high speed, and the product cost is greatly reduced. It becomes possible. In addition, the electric wiring board used for the TAB mounting can be flexibly bent with a flexible board and can be three-dimensionally arranged, so that products such as a liquid jet recording head can be reduced in size and density.

[0006]

The material of a flexible substrate (hereinafter, also simply referred to as a flexible substrate) used for a TAB film generally includes a polyimide resin as a base film (base material), It is composed of a conductor pattern such as a formed copper foil, a polyimide resin or a thin film resist material as a cover coat material, and an adhesive material thereof, and is very thin, flexible and highly flexible, but simple mechanical bending. Sharp bending cannot be performed by processing.

Although the flexible substrate used for the TAB film can be bent freely, as described in Japanese Patent Application Laid-Open No. H6-152077, it is necessary to add another member to maintain a certain shape. Was.

Further, when a heater board (bare chip IC) mounted on a flexible substrate such as a liquid jet recording head is positioned with high accuracy, if the flexible substrate is bent and incorporated without being bent, the bending resistance is reduced. A large frictional force acts due to the force, and the positioning accuracy deteriorates. In addition, there is a danger that the bonded heater board will be cut by the reaction force.

That is, in order to develop a TAB film (flexible substrate) in a product such as a liquid jet recording head so as to take advantage of the TAB mounting technology, there are the following problems in the prior art.

(1) In the case where a flexible substrate is formed by adding another member to the flexible substrate, new components and laminating man-hours are required, the cost is required, and the product becomes expensive.

(2) A sharp bending cannot be performed on the flexible substrate alone, and if the angle of the bending portion is forcibly sharpened and mechanically bent, minute cracks may be generated in the carver coating material of the flexible substrate, This will cause cracks in the copper foil.

In view of the foregoing, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and it is desirable to provide a flexible substrate without generating defects such as cracks and copper foil cracks in the flexible substrate. To provide a bending method and a bending apparatus for a flexible substrate capable of being bent at an angle and a shape, and a liquid jet recording head incorporating a flexible substrate with a heater board bent by the bending method. It is the purpose.

[0013]

In order to achieve the above object, a method for bending a flexible substrate according to the present invention comprises a substrate such as a polyimide resin, a copper foil, and a resist material having a glass transition point as a cover coating material. A step of positioning and fixing one end of the flexible substrate, a step of closely winding the flexible substrate around a reference rod disposed at a bending position on the substrate side, and the resist material of the tightly wound flexible substrate. A heating step of heating the surface with a heat source having a constant temperature lower than the glass transition point for a fixed time.

In the method of bending a flexible substrate according to the present invention, while the flexible substrate is positioned and fixed at one end, the relative position between the flexible substrate and the reference rod is changed to perform the close winding step and the heating step. You can do more than one.

In the method of bending a flexible substrate according to the present invention, the flexible substrate is preferably a TAB film on which a bare chip IC is mounted.

The flexible substrate bending apparatus of the present invention fixes a flexible substrate made of a base material such as a polyimide resin, a copper foil, and a resist material having a glass transition point as a cover coat material by positioning one end thereof. A fixing means, a reference rod having the flexible substrate disposed at a bending position on the base material side, a rotary bending means for closely winding the flexible substrate around the reference rod, and the flexible rod being closely wound around the reference rod by the rotating means. It is characterized by comprising heating means for heating the resist material surface of the flexible substrate with a heat source having a constant temperature lower than the glass transition point for a fixed time, and control means for controlling the temperature of the heat source and the operation of each of the means.

In the flexible substrate bending apparatus of the present invention, the flexible substrate is preferably a TAB film on which a bare chip IC is mounted.

Further, the liquid jet recording head according to the present invention comprises:
A flexible board with a heater board, which is bent by the method for bending a flexible board according to any one of claims 1 to 3, is incorporated.

[0019]

According to the method and apparatus for bending a flexible substrate of the present invention, the flexible substrate is mechanically bent and the cover coat material is heated to thereby obtain a reference rod (lot rod) having a predetermined reference diameter. By minimizing cracks in the bent part and deforming the resist material as a cover coating material by heating without cracking, the shape can be memorized by subsequent cooling, and the flexible substrate can be fixed at a predetermined position. It is possible to bend at an angle, and further, a separate member is not required unlike the related art.

Further, as in the case of the liquid jet recording head, the flexible substrate is formed by bending before being incorporated into the top plate.
The bending reaction force of the flexible board between the heater board and the top board can be significantly reduced, the breakage of the TAB mounted IC without strength can be prevented, and the top board and the heater board that require high-precision alignment The frictional force that increases due to the bending reaction force of the flexible substrate during the positioning can be reduced, and the positioning can be performed with high accuracy. Further, since the bending shape of the flexible substrate can be made constant, the sealing step between the top plate and the heater board after fixing the flexible substrate can be stably performed.

[0021]

Embodiments of the present invention will be described with reference to the drawings.

First, the structure of a flexible substrate (TAB film) incorporated in a liquid jet recording head, which is an example of the present invention, will be described with reference to FIG.

FIG. 3A is a schematic sectional view of the structure of a flexible board (TAB film) on which a heater board as a bare chip IC is mounted, and FIG. 3B is a perspective view showing the flexible board on which the heater board is mounted. It is an explanatory view explaining a mode which mounts a heater board on a TAB tape.

As shown in FIGS. 3A and 3B, a TAB film constituting a flexible substrate (flexible substrate) 1 incorporated in a liquid jet recording head includes a base film 11 as a base material and a conductor pattern. The base film 11 is generally formed of a polyimide resin sheet, and the cover film 13 is generally formed of a polyimide resin. Alternatively, a thin film resist material such as a solder resist is used. As described above, the TAB film is a very thin and flexible substrate which is very flexible and highly flexible as an electric wiring substrate. On the heater board 2, which is a bare chip IC mounted on the TAB film by TAB, an electrothermal conversion element (heater) 2a as an ejection energy generating element for applying ejection energy to ink is provided in a liquid flow path array of a grooved top plate. Are formed at intervals corresponding to. The connection between the bare chip IC (heater board) 2 and the flexible substrate 1
The bonding portion 2c of the heater pattern surface 2b formed in C is bonded with a gold-plated copper foil 14, and a plurality of contact pads on the base film 11 side of the flexible substrate 1 for electrical connection with external electrical device contacts. (Contact) 1
5 are formed in a predetermined pattern shape, and the through holes 16 are formed.
Through the copper foil 12.

Note that T to which the bending method of the present invention is applied is used.
In the AB film, it is important to use a resin having a glass transition point, that is, a resin having a property of softening at a certain temperature, such as an epoxy resin, as a cover coat material.

Also, a bare chip IC (heater board) 2
Is mounted on a TAB film as shown in FIG. T with perforations 18 drilled along both sides of the tape
A plurality of electric wiring boards 1 are provided on the AB tape 17, and a bare chip IC (heater board) 2 is sequentially and continuously bonded to these electric wiring boards 1 at high speed and with high accuracy, and can be TAB mounted. .

When the flexible substrate 1 on which the bare chip IC (heater board) 2 is mounted as described above is incorporated into the liquid jet recording head of this embodiment, it is preferable that the flexible substrate 1 be bent at an angle of about 110 °. This is because, in the liquid jet recording head, the position of the heater board mounted on the flexible substrate and the contact position of the other end of the flexible substrate with the outside are determined by the shape of the top plate of the recording head. This is because the gap between the curved portion of the section and the top plate also requires a work space for applying the sealing material (a nozzle space of the sealing material applying machine), which is a process after assembling the flexible substrate.
In addition, the precision of the shape is required also in the bending of the flexible substrate.

As a method of satisfying these, a method of sequentially bending two predetermined positions of a flexible substrate (TAB film) can realize a bent shape satisfying the above requirements. In FIG. 2 (f), two positions L1 and L2 are bending positions, and a bending device to be described later performs bending processing from a far side to the bare chip IC side.

Next, the configuration of the flexible substrate bending apparatus of the present invention will be described with reference to FIG.

In FIG. 1, a flexible substrate bending apparatus 100 generally includes a fixing means 110 for positioning and fixing the flexible substrate 1, and a reference diameter disposed at a bending position of the flexible substrate 1 on the base material 11 side. Lot bar (reference bar) 1 with
02, a rotary bending unit 120 for tightly winding the flexible substrate 1 around the lot bar 102, a heating unit 130 for heating the flexible substrate 1 closely wound to the lot bar 102, and a control unit for controlling the operations of these units. (Not shown).

The lot rod 102 is fixed to a pair of columns (not shown) erected on a base 105 and serves as a reference for the curvature in bending the flexible substrate 1. The cross section was 2 mm in circular shape. In addition, the part which does not contact the flexible substrate 1 can be cut off.

In the fixing means 110 for positioning and fixing the flexible substrate 1, a mounting table 111 on which the flexible substrate 1 is mounted
Are provided with a plurality of suction holes 112 for vacuum-suctioning and temporarily fixing the flexible substrate 1, and a pair of positioning reference members 115 for abutting the ends of the flexible substrate 1 to position the flexible substrate 1. Further, a pair of fixing members 116 for pressing and fixing both side edges of the flexible substrate 1 are provided. The mounting table 111 is used for the lot bar 10.
The air slide table 114 is supported by an air cylinder or the like, which is movable in the horizontal direction so as to be capable of moving toward and away from the table 2. The air slide table 114 is driven by an air cylinder or the like. By a driving member (not shown) that moves up and down arranged in
The flexible substrate 1 placed on the mounting table 111 is configured to be pressed directly on both side edges to fix the flexible substrate 1 on the mounting table 111.

In the fixing means 110 configured as described above, the flexible substrate 1 is placed on the mounting table 111, vacuum-adsorbed through the suction holes 112, and temporarily fixed.
The positioning member 115 is abutted against the positioning reference member 115 to be positioned. Thereafter, the fixing member 116 is lowered by the operation of a driving member (not shown) and is fixed to the mounting table 111. Then, the air slide table 114 is driven by an air cylinder to move the mounting table 111 so that the flexible substrate 1 fixed to the mounting table 111 is moved to the lot rod 102.
Can be relatively moved with respect to.

The rotary bending means 120 includes a rotary frame 121 rotatably supported by a pair of columns (not shown) erected on the base 105, and air provided in the rotary frame 12. An air slide table 123 with a guide driven by a cylinder and a pressing roller 122 provided so as to be able to approach and separate from the lot bar 102 by the air slide table 123, and the pressing roller 122 moves the air slide table 123. Is moved in the radial direction of the lot bar 102 and pressed against the lot bar 102 in line contact. The pressing load on the lot bar 102 is changed by the movement of the air slide table 123 by driving the air cylinder. The pressure is adjusted, and in this example, it is configured to be pressed with a load of about 1 kgf. The rotary frame 121 is driven to rotate by a rotary cylinder (not shown), and its rotation center is arranged on the same line as the axis O of the lot rod 102.

The rotary bending means 120 constructed as described above
In FIG. 1, the rotary frame 121 is driven to rotate by the operation of a rotary cylinder (not shown), and is adjusted so as to be able to rotate counterclockwise from the initial position shown in FIG.
In this example, the rotation is about 180 °. At the same time as the rotation of the rotary frame 121, the pressing roller 122 and the air slide table 123 also rotate about the axis O of the lot rod 102. In particular, when the flexible substrate 1 is positioned under the lot bar 102, the pressing roller 122
When the air cylinder of the air slide table 123 is driven, it is pressed against the surface of the cover coating material 13 of the flexible substrate 1, and further, the rotary cylinder is driven to rotate about the axis O of the lot rod 102, and the flexible substrate is rotated. 1 is closely wound around the lot bar 102.

The heating means 130 is disposed on the right side of the lot rod 102 in FIG. 1 and is driven by the guide 105 to move horizontally on the base 105 in the horizontal direction. An air slide table with a guide arranged so as to be able to adjust a load for pressing the heater block 131 against the flexible substrate 1 wound closely on the lot bar 102 and a heater block 131 disposed thereon, and driven by an air cylinder. 13
And 2. The heater block 131 is configured to be heated to and maintained at a constant temperature by a cartridge heater (not shown), a thermocouple, and a temperature controller, and is mounted on the air slide table 132 via a heat insulating member 133. Also, the lot bar 102 and the flexible substrate 1 tightly wound therearound are pressed against the left side surface of the heater block 131 so as to be heated.
An arc-shaped concave portion 131a is formed by performing a radius process with a radius of curvature slightly larger than the length obtained by adding the thickness of the flexible substrate 1 to the radius of the lot rod 102.

The heating means 130 thus configured is
In a state where the flexible substrate 1 is closely wound around the lot rod 102, the horizontal moving slider 134 is driven to move leftward in the drawing, and the concave portion 131 a of the heater block 131 is tightly wound around the lot rod 102. The air slide table 13 is brought into contact with the coating material 13.
A constant load is applied by the operation of the second air cylinder, and the flexible substrate 1 is heated in this state. At this time, the air slide table 13 is driven by driving the air cylinder.
The load applied by 2 is set so as to be adjustable, and in this example, it is adjusted so as to add a load of about 1 kgf.

A control means (not shown) controls each means in accordance with a sequence for controlling the bending operation.

Next, the procedure of bending a flexible substrate by the flexible substrate bending apparatus 100 of the present invention will be described with reference to FIG.
Description will be made along (e). FIG. 2 (f) shows two bending positions L1 on the flexible substrate 1.
And L2, and the shape after the first bending process at the bending position L1 is indicated by a dashed line, and the bending position L
2 shows the shape after the second bending process by a solid line, and finally shows the shape formed by bending at about 110 °.

Step 1 (FIG. 2 (a)): The flexible substrate 1 is fixed with its cover coat material 13 down.
10 and temporarily fixed by vacuum suction through the suction hole 112, and in this state, the flexible substrate 1 is slightly moved to abut against the positioning reference member 115 for positioning. Operate the flexible board 1
Is fixed to the mounting table 111.

Step 2 ((b) of FIG. 2): The air slide table 114 and the mounting table 111 are moved by driving the air cylinder, and the initial bending position L1 of the flexible substrate 1 is moved below the lot bar 102. Let me
The air slide table 123 is operated by the air cylinder of the rotary bending means 120, and the flexible substrate 1 is pressed against the lot rod 102 by the pressing roller 122. In this state, the rotary cylinder (not shown) is operated to
2 is rotated counterclockwise in the figure. As a result, while the tension is generated in the flexible substrate 1 between the end portion of the flexible substrate 1 fixed by the fixing member 116 and the portion sandwiched between the pressing roller 122 and the lot bar 102, the flexible substrate 1 is 1 can be tightly wound. At this time, the rotary cylinder (and the rotary frame 12)
The rotation angle of 1) needs to be larger than the required bending angle of the flexible substrate 1. In this example, the required bending angle of the flexible substrate 1 is about 45 °, and the rotation angle of the rotary cylinder is 180 °.
°.

Step 3 (FIG. 2C): heating means 1
Activating the 30 horizontal movement sliders 134 to perform step 2
The heater block 131 is moved to press the heater block 131 against the side of the cover coating material 13 of the flexible substrate 1 which is bent in step (1). The heater block 131 is previously controlled to be heated to a constant temperature by a cartridge heater (not shown), a thermocouple, and a temperature controller.
Air slide table 132 driven by air cylinder
Thereby, the surface of the cover coat material 13 of the flexible substrate 1 tightly wound around the lot bar 102 is pressed and heated with a constant load, and is pressed and heated for a fixed time. In this example, the heating temperature of the heater block 131 was set to 85 ° C. This temperature is a temperature set according to the resist material used as the cover coat material 13 of the flexible substrate 1. In a resist material having a glass transition point (that is, having a property of softening at a certain temperature), the glass transition point is used. It is desirable to set a lower constant temperature.

As described above, the pressing pressure is kept constant by the heater block 131 which is controlled to be kept at a constant temperature, and the flexible substrate 1 is heated for a fixed time to bend.

Thereafter, the horizontal movement slider 134 is operated to separate the heater block 131 from the flexible substrate 1,
The heating means 130 is retracted to the original position. Thereafter, the pressing roller 122 is rotated and returned to its initial position by a rotary cylinder, and the air slide table 123 is lowered by an air cylinder to separate the pressing roller 122 from the flexible substrate 1. Then, the flexible substrate 1 is cooled at room temperature.

Step 4 ((d) in FIG. 2): Next, in order to perform bending at another portion of the flexible substrate 1, the bending position L 2 of the flexible substrate 1 is positioned on the lower surface of the lot bar 102. Then, the air slide table 114 is moved by the operation of the air cylinder to move the flexible substrate 1 together with the mounting table 111. Then, in the same procedure as in step 2, the portion of the flexible substrate 1 at the bending position L2 is closely wound around the lot bar 102 and mechanically bent.

Step 5 (FIG. 2E): Then, the flexible substrate 1 is heated and bent in the same procedure as in Step 3. Thereafter, the heating unit 130 is moved backward, and the pressing roller 122 is returned to the initial position and separated from the flexible substrate 1. The flexible substrate 1 is cooled at room temperature.

Step 6: Finally, the fixing member 116 of the mounting table 111 is released to complete the bent and formed flexible substrate (see FIG. 2 (f)).

As described above, by mechanically bending the flexible substrate and heating the cover coating material, a lot rod having a predetermined reference diameter is used to minimize cracks in the bent portion and heat the cover coating material. The resist material as a material can be deformed without cracks, and the shape can be memorized by subsequent cooling, and the shape can be memorized by bending the flexible substrate at a predetermined position at a predetermined angle. Also,
In particular, when a resist material such as an epoxy resin having a glass transition point is used as a resist material as a cover coat material of the flexible substrate, the flexible substrate is mechanically bent, and the cover coat material of the flexible substrate is moved to the glass transition point. By heating with a heater block controlled to a lower constant temperature, the flexibility of bending a flexible substrate is further increased.

The above-mentioned bending angle includes the temperature of the heater, the heating time, the diameter of the lot bar, the thickness of each material of the flexible substrate, the number of bending points, and the mechanical bending angle (rotation of the rotary cylinder). The angle can be arbitrarily set to a desired angle.

In this embodiment, in order to heat the flexible substrate, the heater block is pressed against the flexible substrate. However, other materials capable of heating (cooling) the cover coat material of the flexible substrate such as an atmosphere furnace. Then, it can be realized by other means.

Next, the flexible substrate 1 (T) with the bare chip IC (heater board) bent as described above is used.
An assembling method of the liquid jet recording head using the (AB film) will be described with reference to FIG.

FIG. 4A shows an embodiment in which a bent flexible substrate (TAB film) is incorporated, and FIG. 4B shows the position of the heater board of the incorporated flexible substrate and the groove of the top plate in the nozzle row direction. FIG. 3C is a partially enlarged view showing an adjustment state, and FIG. 4D is a perspective view illustrating a schematic configuration of a liquid jet recording head.

(1) Nozzle hole row 30a and this nozzle hole row 3
The top plate 30 provided with the liquid flow path row corresponding to Oa is positioned and fixed.

(2) A predetermined angle (for example, about 110
The flexible board 1 with a heater board which is bent in (°) is assembled into the top plate 30. Before the flexible substrate 1 is incorporated into the liquid jet recording head, a hot melt sheet 33 is temporarily fixed to the back side of the contact pad 15 on the TAB tape as an adhesive for bonding a top plate. Each of the heater boards is cut into a predetermined shape one by one from a tape-shaped state and used.

(3) In a state where the heater surface 2b of the heater board 2 on which the heater 2a is formed and the liquid passage 30b row surface of the top plate 30 are in contact with each other, the heater is placed on the nozzle hole row surface (orifice surface) of the top plate 30. The board 2 is pressed with a constant force.

(4) The heater board 2 is arranged such that the center of each heater 2a in the heater row direction on the heater surface 2b of the heater board 2 coincides with the center of each liquid flow path 30b in the liquid flow row array direction of the top plate 30. Is moved with high precision and each center is adjusted.

(5) The heater board 2 is fixed to the top plate 30 by applying a leaf spring 31 without shifting the relative positions of the top plate 30 and the heater board 2.

(6) The contact pads 25 on the other end of the flexible board 1 on which the heater board 2 is mounted are connected to the top plate positioning holes 1c and the positioning holes 30 provided respectively.
Using c, the hot melt sheet 33 temporarily fixed in advance to the back surface side of the contact pad 25 is welded by heating to fix the contact pad 25 of the flexible substrate 1 to the top plate 30. .

(7) A fixed amount of sealing resin is poured into the gap between the top plate 30 and the heater board 2 to prevent ink from leaking from between the top plate 30 and the heater board 2. Further, the sealing resin is also poured into the flexible board 1 on the side of the heater board 2 to increase the fixing strength of the flexible board 1 to the top plate 30.

Through the above steps, the mounting of the flexible board 1 with the heater board on one side of the top plate 30 is completed.
By performing the same process on the other side of the top plate 30, the flexible substrates 1 with the heater boards 2 can be incorporated on both sides of the top plate 30, respectively.

(8) The top plate 30 in which the flexible board 1 with the heater board is incorporated on both sides is attached to the ink sealing material 34.
And assembled to the ink tank 32 via a connecting screw or the like.

In the liquid jet recording head finally assembled in this manner, the nozzle hole array 30a and the liquid flow channel array 30b of the top plate 30 and the heater array 2a of the heater board 2
Are positioned with high precision.
Contact pattern (contact pad) 25 is also accurately positioned with respect to the top plate for contact with the outside.
The sealing resin seals around the heater board 2 to prevent ink from leaking from portions other than the nozzle holes for ink ejection.

Further, a flexible substrate 1 with a heater board
Is bent at a predetermined position at a predetermined angle before being assembled into the top plate 30, so that even when the angle at the time of assembling the top plate is large, the bending reaction force of the flexible substrate applied to the top plate and the heater board can be reduced. It can be kept to a minimum. Further, it is possible to accurately reproduce the end position and the bending position where the contact with the outside of the flexible substrate is provided.

[0064]

As described above, according to the present invention,
By mechanically bending the flexible substrate and heating the cover coat material, the crack at the bent portion is minimized with a lot rod having a predetermined reference diameter and the resist material as the cover coat material is cracked by heating. It can be deformed without causing it, and the shape can be memorized by subsequent cooling, and the flexible substrate can be bent at a predetermined position and at a predetermined angle, and does not require a separate member as in the conventional case.

Further, by bending the flexible substrate before assembling it on the top plate as in the example of the liquid jet recording head,
Since the bending reaction force of the flexible board between the heater board and the top plate can be significantly reduced, (1) disconnection of the TAB mounted IC without strength can be prevented, and (2) high-precision alignment is required. The frictional force that increases due to the bending reaction force of the flexible substrate when the top plate and the heater board are aligned can be reduced, and highly accurate alignment can be performed. Furthermore, since the bending shape of the flexible substrate can be made constant, (3)
The sealing step between the top plate and the heater board after fixing the flexible substrate can also be performed stably.

As described above, according to the present invention, a product such as a small liquid jet recording head utilizing TAB mounting can be provided, and the cost of the manufacturing apparatus can be reduced. Since the number of manufacturing steps can be reduced, it is possible to manufacture a less expensive product such as a liquid jet recording head.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a configuration of a flexible substrate bending apparatus according to the present invention, which is partially cut away.

FIG. 2 is a process diagram showing a bending process of a flexible substrate according to the present invention.

3A and 3B are diagrams illustrating a configuration of a flexible substrate (TAB film) incorporated in a liquid jet recording head, which is a target example of the present invention. FIG. 3A is a schematic diagram illustrating a configuration of a flexible substrate on which a heater board as a bare chip IC is mounted. Is a typical sectional view,
(B) is a schematic perspective view of a flexible board on which a heater board as a bare chip IC is mounted, and (c) is an explanatory diagram for explaining a mode of mounting the heater board as a bare chip IC on a TAB tape.

FIG. 4 is a schematic diagram illustrating a method of assembling a liquid jet recording head which is an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible board (TAB film) 2 Heater board (bare chip IC) 2a Heater (row) 11 Base film (base material) 12 Copper foil 13 Cover coat material (resist material) 15 Contact pad 17 TAB tape 30 Top plate 30a Nozzle hole ( Row) 30b liquid flow path (row) 31 leaf spring 32 ink tank 33 hot melt sheet 100 bending apparatus 102 lot bar (reference bar) 110 fixing means 111 mounting table 112 suction hole 114 air slide table 115 positioning reference member 116 fixing member Reference Signs List 120 Rotating bending means 121 Rotating frame body 122 Press roller 123 Air slide table 130 Heating means 131 Heater block 131a Depression 132 Air slide table 133 Heat insulating member 134 Horizontal movement slider

Claims (6)

[Claims] 1. A step of positioning and fixing one end of a flexible substrate composed of a substrate such as a polyimide resin, a copper foil and a resist material having a glass transition point as a cover coating material, and fixing the flexible substrate to the substrate side. And a heating step of heating the resist material surface of the tightly wound flexible substrate with a heat source at a constant temperature lower than a glass transition point for a fixed time. A method for bending a flexible substrate. 2. The method according to claim 1, further comprising: performing a plurality of close winding steps and a plurality of heating steps by changing a relative position between the flexible substrate and a reference rod while the flexible substrate is positioned and fixed at one end thereof. A method for bending a flexible substrate according to the above. 3. The method for bending a flexible substrate according to claim 1, wherein the flexible substrate is a TAB film on which a bare chip IC is mounted. 4. A fixing means for positioning and fixing one end of a flexible substrate made of a base material such as a polyimide resin, a copper foil and a resist material having a glass transition point as a cover coating material, and fixing the flexible substrate to the base material. A reference rod disposed at a bending position on the side, a rotary bending means for closely winding the flexible substrate around the reference rod, and the glass transition point of the resist material surface of the flexible substrate tightly wound around the reference rod by the rotating means. An apparatus for bending a flexible substrate, comprising: a heating means for heating for a fixed time with a heat source having a lower constant temperature; and a control means for controlling the temperature of the heat source and the operation of each of the means. 5. The bending apparatus according to claim 4, wherein the flexible substrate is a TAB film on which a bare chip IC is mounted. 6. A liquid jet recording head incorporating a flexible board with a heater board bent by the method for bending a flexible board according to any one of claims 1 to 3.