JPH07132626A - Current supply recording head - Google Patents

Abstract

PURPOSE:To provide a current supply recording head capable of printing a stable image of high resolving power uniform in the lateral direction of the head, easily increased in length, easy to mass-produce and having a small-sized and simple structure as a current supply recording head bringing a return passage electrode and a recording electrode into contact with a printing recording medium to supply a current thereto to form an image on recording paper. CONSTITUTION:A recording electrode 2, a drive circuit 3 and a connector electrode 4 are integrally arranged on a flexible insulating film 1 to constitute a head principal part 5 and the cut gap parts formed to the wiring pattern parts 2a of the recording electrode in the head principal part 5 are filled with a resistor material to provide a stabilizing resistor 12. The head principal part 5 is laminated on a rigid support 7 through an elastic member 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric recording head used in an electric recording system and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, image formation by the electric recording method is performed as follows. That is, a print recording medium provided with a heat generating layer that generates heat when energized and a hot-melt ink layer that melts due to heat generation of the heat generating layer is used, and a plurality of independent recording electrodes are arranged in parallel on the heat generating layer side of the print recording medium. The provided recording head is brought into contact with the recording head, and the recording electrodes of the recording head supply electricity corresponding to the image information to heat the heating layer in the energized portion, and the heat-melt ink layer corresponding to that area is melted for recording. An image is formed by transferring the image onto a sheet. At this time, the return electrodes are simultaneously in contact with the print recording medium.

Generally, in an electric recording head used in such an electric recording system, recording electrodes are provided in parallel on a rigid support, and image information is transferred to a recording electrode on a substrate separate from the rigid support. A drive circuit for applying an electric signal according to the above, and a connector electrode for connecting and inputting an image information signal or the like from the image forming apparatus main body to the drive circuit, and the recording electrode, the drive circuit and the connector. A current-carrying recording head having a structure in which electrodes are electrically connected is known. However, in the conventional energization recording head, since the recording electrode is provided on a rigid support such as ceramic, and the head itself has no flexibility,
For example, if there is unevenness on the contact surface of the print recording medium, the recording electrodes do not come into uniform contact with each other, which causes print defects in the print dots, variations in dot shape, and the like, resulting in image defects.

In order to prevent the contact failure of the recording electrodes,
The present applicant has previously proposed a recording head in which a recording electrode is provided on a rigid support via an elastic layer (Japanese Patent Laid-Open No. 63-63).
47151 publication). However, according to this recording head, although the contact failure of the recording electrode is improved by the elastic action of the elastic layer as compared with the conventional product, the contact stability of the recording electrode in the width direction of the head is insufficient. . Therefore, it is difficult to make the head longer (wider).
That is, as the length increases, the contact of the recording electrodes in the width direction tends to become more uneven, which easily causes image defects.

On the other hand, all the conventional energization recording heads are
Since the recording electrode and the drive circuit for the recording electrode are provided on separate supports (substrates), the connecting portions between the two are very complicated, and as a result, the entire recording head has a large and complicated structure. There is also a problem that it becomes difficult to replace the head. Further, with the structure as described above, it is more difficult to lengthen the head, or the connecting portion thereof is easily broken or short-circuited due to vibration or the like.
There is a problem that the overall size becomes relatively large. Further, in the conventional recording head, when the drive circuit is driven at a constant voltage, the current value of the image signal sent to each recording electrode is unstable due to the instability of the contact resistance value of the electrode tip, the change of the contact state, etc. And it becomes difficult to print stable and good images. This problem tends to be exacerbated by the unevenness of current flow caused by non-uniform contact of the recording head with the print medium.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art as described above, and an object of the present invention is to provide uniform, high resolution and stable in the width direction of the head. An object of the present invention is to provide a small-sized and simple structure of an electric recording head capable of printing an image, easily lengthened, and easily mass-produced.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that recording electrodes, drive circuits and connector electrodes are integrally arranged on a flexible insulating film. However, in this case, even if an ordinary resistor is connected and wired to the connector electrode portion etc. as is generally done in order to obtain stable image printing, a solution to the problem is found. It has been found that since the main part of the head is made compact by an integral structure, a sufficient space for connecting and connecting the head is lost, which is almost impossible.

Therefore, as a result of further research based on the above findings, it was found that all the above objects can be achieved by providing a new stable resistor in the wiring pattern portion of the recording electrode, and the present invention is completed. I arrived.

That is, the electrically conductive recording head of the present invention is an electrically conductive recording head for forming an image by bringing a return electrode and a recording electrode into contact with a print recording medium to energize the recording electrode, and the recording electrode is formed on a flexible insulating film. The drive circuit and the connector electrode are integrally arranged to form a main part of the head, and the cutting gap formed in the wiring pattern part of each recording electrode in the main part of the head is filled with a resistor material. It is characterized in that a stabilizing resistor is provided.

Further, in the energization recording head of the present invention, in the above-mentioned technical means, the stabilizing resistor is formed in an integral shape continuous between the wiring pattern portions of the recording electrode, or the head main portion is rigidly supported. It is characterized by being laminated on the body via an elastic member, or integrally provided with a return path electrode capable of coming into contact with the print recording medium.

The present invention will be described below with reference to the drawings.

As shown in FIG. 1, the energization recording head of the present invention has a recording electrode 2, a driving circuit 3 and a connector electrode 4 which are integrally provided on a flexible insulating film 1 so that a head main portion 5 is formed. A stabilizing resistor 12 for each electrode portion is provided at a predetermined portion of the wiring pattern portion 2a of each recording electrode 2. Further, in this electric recording head, the head main part 5 is laminated on the rigid support 7 via the elastic member 6. Reference numeral 13 shown by a chain double-dashed line in the figure is a return electrode. Further, in the figure, 8 is a bump portion formed on the tip of the recording electrode 2, 9 is a wire connection, 10 is an insulating protective layer,
Reference numerals 11 respectively indicate coating films.

Examples of the flexible insulating film 1 include synthetic resin films made of polyimide, polyethylene terephthalate, polyaramid, polysulfone and the like, preferably 10 to 150 μm in thickness, more preferably 10 to 40 μm in thickness. The heat resistant film of is used. If the thickness of the film 1 is thinner than 10 μm, it becomes difficult to handle at the time of manufacturing a head or to mount an IC chip or the like. This is an obstacle to obtaining the pressure contact property of the head (recording electrode). And the thickness is 40 μm
When the amount is in the following range, a better elastic action can be efficiently obtained. Further, since this film 1 is required to withstand heat generation during printing and high temperature environment during manufacturing so as not to be deteriorated, the temperature is 200 ° C. or higher, more preferably 25 ° C.
It is desirable to have a heat resistance of 0 ° C or higher.

More specifically, the recording electrode 2 is composed of a wiring pattern portion 2a having a predetermined width and pitch, for example, a striped fine line pattern, and a bump portion 8 formed at the tip of the pattern portion. The print width of the recording head is set by the number of recording electrodes (wiring pattern portions). The bump portion 8 of the recording electrode 2 is a protrusion for efficiently and reliably bringing the recording electrode into contact with the surface of the recording medium when the recording head is pressed against the print recording medium. It is preferable that the bump portion 8 has a convex shape such that the height of the top surface from the surface of the insulating protective layer 10 is 11 μm or more and 60 μm or less. If the height of the top surface of the bump portion 8 is less than 11 μm, the above function of the bump portion is not exerted. On the contrary, if it exceeds 60 μm, it is difficult to obtain a uniform pressure contact pressure between the bumps, and the manufacturing itself becomes difficult. There is a problem such as becoming.

The wiring pattern portion 2 of the recording electrode 2
a and the bump portion 8 are made of copper, nickel, molybdenum, tungsten, rhodium, titanium, ruthenium, nickel,
Mainly composed of metal such as chrome or its alloy material.
The wiring pattern portion 2a and the bump portion 8 are preferably formed of a hard alloy having a Vickus hardness of 100 or more,
In order to further improve the abrasion resistance, it is more preferable to form a composite metal material in which ceramic powder, carbon powder and lubricant powder are dispersed in the above metal or its alloy material. In particular,
It is even more preferable to form them by electroplating, electroless plating, or composite plating, because the effect of using the above materials can be more easily obtained.

The stabilizing resistor 12 is formed by forming a cutting gap portion for completely cutting and dividing the wiring pattern portion 2a of each recording electrode 2 at a predetermined position, and then forming a predetermined resistor material. It is formed by filling a predetermined amount. The stabilizing resistor 12 has a wiring pattern portion 2a.
Of the recording electrodes are formed independently of each other, or as shown in FIG. 1A, they are formed in a continuous integral shape so as to traverse between the wiring pattern portions 2a of the recording electrodes. In the case of forming in the latter case, the same function as in the case of forming in the former case can be obtained, and the forming work becomes easy, leading to improvement in production efficiency.

The stabilizing resistor 12 functions as a protective resistor, and the current value of the image signal (instantaneous).
It has the effect of suppressing the change and preventing the flow of a large current due to a short circuit of the bump portion of the recording electrode, which greatly contributes to the stabilization of image printing. Therefore, the resistance value of the stabilizing resistor is within the range of 0.5 to 100%, preferably 2 to 50% of the resistance value of the heat generating layer in the print recording medium. If this resistance value is smaller than 0.5% of the resistance value of the heat generating layer, the effect of stabilizing the current becomes small. On the contrary, if it exceeds 100%, the main heat generation in the recording circuit system occurs. There is a problem in terms of energy efficiency because the portion becomes the stabilizing resistor portion instead of the heat generating layer portion.

As the resistor material forming the stabilizing resistor 12, any material can be used so long as it has the above-mentioned predetermined resistance value, for example, a polymer material in which a conductive material such as carbon-dispersed polyimide is dispersed, or a polymer material in which conductive material is dispersed. Thin film metal materials such as titanium, nickel, tungsten, gold, platinum, molybdenum,
A conductive ceramic material such as tantalum pentoxide, ruthenium oxide, silicon nitride, or boron nitride, or a composite material including a conductive material such as titanium / silica oxide dispersion material and an insulating material is used. Therefore, the stabilizing resistor 12 is filled with such a resistor material in the cutting gap formed in the recording electrode wiring pattern portion by means such as a screen printing method, a vacuum deposition method, a sputtering method, a solvent coating method, It is formed by performing post-treatment such as heat treatment as necessary.

The drive circuit 3 formed integrally with the flexible insulating film 1 is constructed by mounting a pulse signal driving IC chip or the like. As a method of connecting the recording electrode wiring pattern portion 2a and the contact electrode 4 of the drive circuit, a flip chip mounting connection method, an anisotropic conductive film connection method, or the like may be adopted in addition to the wire bonding method. The wire bonding method is most preferable because it has good current resistance and connection reliability.

In the case where the above wire connection is performed by the wire bonding method, the following work can be performed before the wire connection so that the bonding work to each wire connection portion can be performed reliably and stably. Further, it is possible to make a connection with higher yield. For example, a hard metal portion is provided on each of the wire connecting portions of the recording electrode wiring pattern portion 2a and the connector electrode 4 by various plating methods, and the wire connecting work is performed using the hard metal portion. In this case, since the bonding strength of both connection portions is excellent, there is an advantage that disconnection or the like is less likely to occur. Moreover, if the electrodes are made of hard metal,
Even if the electrode thickness is thinner than 50 μm, wire bonding connection with sufficient connection reliability is possible.

Further, in order to improve the reliability of the connection and the reliability of the mounting of the drive circuit 3, at least between the flexible insulating film of the main part of the head and the elastic member, and at least the rear end of the recording electrode. You may arrange | position a hard thin plate in the site | part from a part side to a connector electrode side. The hard thin plate may be one that can impart rigidity to the connection work area particularly so that the connection part does not sink due to the contact pressure at the time of wire bonding, and specifically, from stainless steel, phosphor-bronze, aluminum or the like. Thickness is 100 μm or less, preferably 20
It is a thin plate of ˜50 μm. When the hard thin plate is provided in this way, for example, since the connection portion is indirectly reinforced by the hard thin plate, unnecessary deformation of the connection portion is suppressed and disconnection is prevented, or the hard thin plate is a drive circuit. IC
There are advantages such as acting as a heat sink for the chip.

As the elastic member 6, rubbers such as silicone rubber and urethane rubber, porous substances, foaming substances and the like are used. This elastic member has, for example, a rubber hardness of 10 to 10.
It is in the range of 60, preferably 20-50. If the rubber hardness is less than 10, the pressure contact pressure of the recording head cannot be sufficiently applied, and it becomes difficult to perform elastic pressure contact with the print recording medium. On the contrary, if it exceeds 60, an appropriate elastic action cannot be obtained. However, there is a possibility that the contact failure of the recording electrode is likely to occur. Moreover, the thickness of the elastic member 6 is 0.5 to 60 m.
m, preferably 3 to 20 mm. If this thickness is less than 0.5 mm, it is difficult to obtain sufficient elasticity as an elastic material. On the other hand, if it exceeds 60 mm, the size of the entire head becomes large and the contact state of the head tip becomes unstable. There are problems such as being easy.

The material, thickness, etc. of the rigid support 7 are not particularly limited as long as they have the rigidity with which the recording head can be brought into pressure contact with a desired pressure, and can be appropriately selected. Specifically, a glass epoxy material, a metal plate such as aluminum, or the like is used.

In the energization recording head of the present invention, first, the head main part 5 having the above-mentioned structure is prepared, and then the head main part 5 is mounted on the rigid support 7 via the elastic member 6.
It can be manufactured by stacking and integrating them on top.

The main part 5 of the head can be manufactured, for example, as follows, but the method is not necessarily limited to this method. That is, as shown in FIGS. 2A to 2E, first, the metal thin film 14 is formed on the flexible insulating film 1.
(FIG. 7A), and thereafter, the metal thin film 12 is etched by a photolithography method or the like to form cutting gaps 15 in the wiring patterns 2a and 4a for the recording electrodes and the connector electrodes and the recording electrode wiring pattern 2a. It is formed (the same figure b). In FIG. A, 16 is a pad portion for mounting an IC chip or the like which constitutes the drive circuit 3. Next, after the insulating protective layer 10 is formed only on a predetermined portion except on the cutting gap portion 15 (FIG. 7C), the cutting gap portion 15 is filled with a resistor material by an appropriate method to obtain a predetermined amount. Post-processing is performed to provide the stabilizing resistor 12 (FIG. 11D).

Next, the tip portion of the recording electrode wiring pattern 2a, the pad portion 11 and the like are coated with a predetermined metal such as nickel by plating to form the bump portion 8 and the wire bonding portion 17, and then the pad portion 16 is formed. The IC chip 3 for the drive circuit and the like are die-bonded onto the wire bonding portion 1 (FIG. 2d). Finally, the connection 9 between the recording electrode 2 and the drive circuit 3 and between the drive circuit 3 and the connector electrode 4 is performed,
The coating film 1 so as to cover the drive circuit 2 and its peripheral portion.
By forming 8, the head main part 5 as illustrated in FIG. 2 (e) is obtained.

For laminating the head main part 5, the elastic member 6 and the rigid support 7, an adhesion method using an adhesive such as a silicone adhesive or an epoxy adhesive is usually applied. This lamination can be performed by an appropriate method other than the above-mentioned bonding method, such as stacking them via the rubber material of the elastic member 6 and mechanically pressure-bonding them from both sides.

The return electrode 13 provided integrally with the energizing recording head is in contact with the print recording medium (the energizing layer is actually in contact with the return electrode) together with the recording electrode 2 (bumps 8) during recording. It is possible. The position and form of the return electrode are not particularly limited, but it is preferable that the return electrode is provided so as to come into contact with the print recording medium at a position as close as possible to the bump portion. The return electrode can be formed, for example, by pressing and fixing a blade-shaped blade-shaped, arc-shaped, or roll-shaped electrode member and then removing an unnecessary conductive portion. In this way, when the return path electrode is provided integrally with the energization recording head, there are advantages such as prevention of energy loss during printing and recording, and miniaturization of the energization recording apparatus.

The print recording medium 20 used for recording by the energizing recording head of the present invention is shown in FIGS.
As shown in FIG. 7, it is sufficient that the heat-generating layer 21 and the conductive layer 22 that generate heat when energized according to the image formed from the recording electrode 2 that is pressed are provided, and the hot-melt ink layer 23 that melts due to the heat generation.

Electrostatic recording by the electric recording head of the present invention is performed as shown in FIG. 3 or 4. 2 in the figure
Reference numeral 4 denotes a recording sheet, and 25 denotes a back surface pressure contact material (pressure contact roll or the like) having excellent surface smoothness.

That is, when an energizing recording head which is not integrally provided with a return electrode is used, as shown in FIG. 3, the recording electrode 2 of the energizing recording head is used.
The (bump portion 8) is formed on the surface of the print recording medium 20 (heating layer 2).
1) and at the same time the separate return electrode 26 is in contact with the conductive layer 22 of the print recording medium 20.

The return electrode 1 is used as an energizing recording head.
3 is integrally provided, as shown in FIG. 4, the recording electrode 2 (bump portion 8) of the energization recording head and the return electrode 13 are simultaneously brought into contact with the print recording medium 20. Do it in the open state. Actually, the recording electrode 2 is replaced by the heating layer 2
1, the return path electrode 13 is brought into direct contact with the conductive layer 22, but when a recording electrode having a large contact area is used, it may be brought into contact with the medium surface as shown (in this case, Can also secure a sufficient return current path).

[0033]

The current-carrying recording head of the present invention is used in a current-carrying recording system, and in recording the current-carrying recording head, the current-carrying recording head is brought into pressure contact with the print recording medium so that a plurality of recording electrodes (bumps) at the edge of the head cause the recording medium surface to come into contact. Make sliding contact. Then, the image information signal input from the contact electrode is distributed and applied as electric signals to predetermined recording electrodes by the drive circuit, the heat generating layer portion corresponding to the applied recording electrode generates heat, and the heat generating layer portion that generates heat is applied to the heat generating layer portion. The corresponding hot-melt ink layer is melted and transferred to the recording paper, whereby an image is recorded.

At this time, in the recording head of the present invention, the image signal from the drive circuit driven by a constant voltage passes through the stabilizing resistor provided in the middle of the wiring pattern of the recording electrode, and the image signal current Instantaneous changes can be reduced, and as a result, heat generation in the print recording medium can be performed accurately and in a stable state, which in turn enables reliable and stable image printing. This stabilizing resistor can be easily provided during the process of forming the main part of the head, and this effect is remarkable when the stabilizing resistor is formed into a continuous integral shape between the wiring pattern portions of the recording electrodes. can get.

When the main part of the head is provided on the rigid support through the elastic member, the elastic deformation of the elastic member absorbs the unevenness of the print recording medium, the unevenness of the back roll and the like, and the flexure. Always contacts the print recording medium uniformly and stably over the entire area.

[0036]

The present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples.

Example 1 As shown in FIG. 2a, a 12 μm thick copper foil 14 was adhered and laminated on a 25 μm thick polyimide film 1 with a silicone adhesive. Next, a resist is applied on the copper foil 12, and the resist is patterned by pattern exposure and development, and then the copper foil is etched to form the basic wiring patterns 2a and 4a and the stabilizing resistor characteristic cutting gap portion 1.
5 was formed on a polyimide film (Fig. 2b). The gap width of the cutting gap portion 15 at this time is about 300 μm.

Next, nickel plating is applied to the entire surface of the wiring pattern except the cutting gap 15 so as to have a thickness of 1.5 μm to form an anticorrosion film, and then a photosensitive amic acid is applied to the entire surface, followed by photolithography. Application at positions of the bump forming portion and the cutting gap portion forming portion of the recording electrode wiring pattern, the wire bonding pad portion of the drive circuit and the connecting portion of the connector electrode, and the connection forming portion of the cutting gap portion between the wiring pattern portions 2a The film was removed, and thereafter, heat treatment was performed to heat and cure the coating film on the remaining portion to form an insulating protective layer 10 having a thickness of 5 μm (FIG. 2C).

Next, a low temperature processing type thermal head resistor (RuO ₂ and Si) is formed in the cut gap portion 15 between the wiring pattern portion 2a and the cut gap portion connection forming portion between the wiring pattern portion 2a.
A mixed material of O ₂ ) was applied and filled by a screen printing method, and then heat treatment was performed at 280 ° C. to provide a stabilizing resistor 12 (resistance value: 15 Ω / piece) having a thickness of 30 μm. The stabilizing resistor 12 has a wiring pattern portion 2a of the recording electrode.
It is an integral shape that is continuous between.

Next, the bump forming portion formed at the tip of the recording electrode wiring pattern portion 2a was plated with a phosphorus-nickel material having a thickness of 25 μm by the nickel plating method to form the bump portion 8. Then, after plating the wire bonding pad portion 13 and the contact electrode portion 4 with a thickness of 8 μm, the signal pulse driving IC (thermal head driver IC) 3 was die-bonded onto the wire bonding pad portion 13 on the film 1. (Fig. 2d).

Next, using a gold wire of 25 μmφ, I
Bonding pad on C chip and bonding pad (wiring part) on wiring pattern of recording electrode and connector electrode
After connecting 9 and 9, the peripheral area on the IC chip is covered with a silicone resin to form a coating film 11, and finally, a polyimide film that has been subjected to these various processing steps has a predetermined size corresponding to a head unit. It was cut into pieces and divided into head units to form a head main part 5 (FIG. 2e).

Then, the head main portion 5 is adhered onto a silicone rubber support 6 having a rubber hardness of 40 and a thickness of 4 mm, and then the back surface side of the rubber support 6 has a thickness of 30 m.
It is adhered on the aluminum base material 7 of m and the printing width is 50 m.
An electric recording head having m and a resolution of 12 dots / mm was prepared (FIG. 2f). The bump portion 8 in the recording electrode of this recording head had a planar size of 60 μm × 45 μm, and the top of the bump portion had a convex shape protruding 18 μm from the surface of the insulating protective layer 10.

Using the recording head thus obtained, as shown in FIG. 3, the recording head is brought into pressure contact with the ink ribbon 20 for electric transfer at a linear pressure of 300 g / cm, and at the same time, a separate return path electrode is brought into contact with the recording head to apply an applied voltage of 8 V, Printing and recording were performed under image (dot) signal conditions with a pulse width of 300 μsec. Then, with respect to the print image on the recording paper obtained at that time, print density, dot shape, dot size uniformity, and print rate (at the initial stage) were measured and evaluated. The results are shown in Table 1. At this time, there were few print omissions and dot variations in the head width direction, and they were not at a level that would cause a problem in image quality by visual evaluation.

The print density is measured by an optical reflection densitometer,
Regarding the results, excellent (greater than the measured density value of 1.3), good (1.3 to 1.0 for the same), acceptable (1.0 to 0.8 for the same), poor (0.8 to 0.5 for the same). ) And no (less than 0.5). Regarding the dot shape, the shape of the printed dots was visually observed, and the results were evaluated in 5 grades: excellent, good, good, bad, and bad. The dot size uniformity is excellent (dot variation width: R <10%), good (10 <R <20
%), Acceptable (20 <R <30%), defective (30 <R <50
%) And impermissible (R> 50%). The printing rate indicates the rate of actual printing with respect to the image input signal at the initial stage.

The size and shape of the print dot at each point (print position) in the head width direction shown in Table 1 were measured,
I observed. The results are shown in Table 1. In addition, the printing rate with respect to the image input signal at this time was 100%, and no print omission occurred in the head width direction.

Example 2 Example 1 was repeated except that the silicone rubber member 6 was not used and the head main portion 5 was directly bonded onto the aluminum member 7.
An energization recording head was prepared in the same manner as in. Using the energization recording head, the same printing and recording as in Example 1 and each measurement were performed, and the results are also shown in Table 1.

Comparative Example 1 An electric recording head was prepared in the same manner as in Example 1 except that the stabilizing resistor 12 was not provided. Using the energization recording head, the same printing and recording as in Example 1 and each measurement were performed, and the results are also shown in Table 1.

Comparative Example 2 The plating thickness of the bump portion 8 of the recording electrode in Example 1 (2
An electric recording head was prepared in the same manner as in Example 1 except that the thickness (5 μm) was changed to 15 μm. The bump portion 8 of the formed recording electrode has an average height from the surface of the insulating protective layer 10 of 3 μm.
Met. Using this recording head, a abrasion resistance test of the recording electrodes (bumps) was carried out by running for 2 km on a pseudo ink medium, and then the same print recording and each measurement as in Example 1 were carried out, and the results are shown in Table 1. It is shown together with. Note that the parenthesized writing in the table is the result when the same print recording and each measurement as in Example 1 were performed (in the initial state) without performing the abrasion resistance test.

Example 3 A 20 μm thick copper foil was coated with a polyimide precursor in a thickness of 20 μm and dried, and then a copper foil was coated with a photoresist and dried by heating. The wiring pattern was exposed, developed, and etched. Then, each wiring pattern (the wiring pattern portion of the recording electrode has a width of 45 μm and a pitch of 64 μm) and the cutting gap portion for forming the stabilizing resistor (gap width: about 500 μm) were formed.

Then, a portion of 20 μm inside the tip of the wiring pattern portion of the recording electrode is applied to the polyimide front layer to form a hole portion of 40 μm square by photoresist means, and then,
In the nickel plating step, plating was grown in this hole and nickel plating having a thickness of 25 μm was applied to form bumps in the recording electrode.

Next, tantalum pentoxide was deposited to a thickness of 0.2 μm by a mask RF sputtering method in the cut gap portion formed in the wiring pattern portion of the recording electrode, and a stabilizing resistor (resistance value: 60 Ω / piece) was formed. Was set up.

After the above vapor deposition is completed, the temperature is 380 ° C. and the temperature is 30 ° C.
The polyimide precursor was imidized by performing heat treatment for 1 minute to form a polyimide film layer (flexible insulating film) having a thickness of 12 μm. At the same time, the nickel plating film was hardened.

Next, in the nickel plating step, an IC is formed simultaneously by thickening the film by nickel plating.
After die-bonding the driving IC chip on the mounting pad portion, wire bonding the IC chip and the connector electrode portion with a 20 μmφ gold wire, and then covering the peripheral region on the IC chip with a silicone resin, The flexible printed circuit (FPC) was completed.

This FPC was adhered and laminated on the same silicone rubber member and aluminum support as in Example 1 in the same order to obtain a print width of 200 mm and a resolution of 16 dots / m.
An m recording head was manufactured. The bump portion of the recording electrode in this recording head has a plane size of 30 μm × 35.
The protrusion height from the polyimide film layer surface is 8μ in μm
It had a convex shape of m.

Using this recording head, after printing and recording were carried out in the same manner as in Example 1 except that the image signal conditions were an applied voltage of 19 V and a pulse width of 500 μsec, the same various measurements as in Example 1 were carried out. The results are shown in Table 1.

Example 4 A 13 μm copper foil was coated with a polyimide precursor to a thickness of 15 μm and dried, and then a photoresist was applied to the copper foil surface and dried by heating. The wiring pattern was exposed, developed and etched. Wiring pattern (wiring pattern part of recording electrode: width 4
5 [mu] m, pitch 64 [mu] m) and stabilizing resistor forming cutting gaps (gap width: about 2 mm) were formed.

Next, a hole of 23 .mu.m.quadrature. Is formed by a photoresist means by covering the portion of the wiring pattern portion of the recording electrode, which is 20 .mu.m inside from the tip, with the polyimide front layer, and
By the nickel plating process, plating is grown in this hole portion and nickel plating with a thickness of 12 μm is performed, and rhodium is plated with a thickness of 3 μm on the nickel plating layer.
The bump portion of the recording electrode was formed.

Next, carbon-dispersed polyimide was applied to the cut gap portion of the wiring pattern portion of the recording electrode by a screen printing method, and was heated and dried at 190 ° C. for 30 minutes to give a thickness of 5.
A μm stabilizing resistor was provided.

After forming the above-mentioned stabilizing resistor, 300 °
The polyimide precursor was imidized by performing a heat treatment for 30 minutes at C to form a polyimide film layer having a thickness of 7 μm.

Next, the driving IC chip is die-bonded onto the IC mounting pad portion which is formed at the same time by thickening the film to about 5 μm by nickel plating in the nickel plating step, and then a gold wire of 20 μmφ is used. The IC chip and the connector electrode portion were wire-bonded, and then the peripheral area on the IC chip was covered with a silicone resin to complete a flexible printed circuit (FPC).

This FPC was adhered and laminated on the same silicone rubber member and aluminum support as in Example 1 in the same order to produce an electrically conductive recording head having a print width of 50 mm and 16 dots / mm. The bump portion of the recording electrode of this recording head had a convex shape with a planar size of 46 μm × 39 μm and a protrusion height of 12 μm from the surface of the polyimide layer.

Using this recording head, after printing and recording were carried out in the same manner as in Example 1 except that the image signal conditions were an applied voltage of 16 V and a pulse width of 0.8 msec, various measurements were carried out and the results are shown. Shown in 1. Using this recording head, a recording electrode (bump portion) was run for 1 km on a pseudo ink medium for an abrasion resistance test, and the same print recording as above was performed. The print ratio was 98.4%. The print dots were almost evenly printed.

Example 5 A 15 μm-thick copper foil was adhered and laminated on a 30 μm-thick polyimide film with a silicone adhesive. Next, a resist is applied on the copper foil, and the resist film is patterned by pattern exposure and development, and then the copper foil is etched to form a basic wiring pattern and a gap portion for forming a stabilizing resistor (gap width: 100 μm ) Is a polyimide film 1
Formed on.

Next, after nickel plating is applied to the entire surface of the wiring pattern so as to have a thickness of 1.5 μm to form a corrosion resistant film, a photosensitive amic acid is applied and a bump of the wiring pattern for the recording electrode is formed by photolithography. The forming portion and the cutting gap portion forming portion, the wire bonding pad portion of the drive circuit and the connecting portion of the connector electrode, and the coating film at the position which becomes the connection forming portion of the cutting gap portion between the wiring pattern portions are removed,
Then, heat treatment was performed to heat-cure the coating film on the other remaining portions to form an insulating protective layer having a thickness of 5 μm.

Next, a screen printing paste containing ruthenium as a main component is applied to the cutting gap of the wiring pattern portion of the recording electrode by a screen printing method and heat-cured,
A stabilizing resistor having a thickness of 25 μm was provided.

Next, a bump portion having a thickness of 25 μm was formed on the bump forming portion formed at the tip of the wiring pattern portion of the recording electrode by a composite plating method using nickel in which SiC fine particles were dispersed. Then, a gold plating having a thickness of 8 μm was applied on the wire bonding pad portion and the connection portions of the recording electrode and the contact electrode portion.

Then, a signal pulse driving IC (driver IC for thermal head) is die-bonded on the wire bonding pad portion on the film, and then 100 μm is formed on the back surface of the film at a portion immediately below the pad portion.
A m-thick stainless plate was placed and subjected to a lining treatment.

Next, using a gold wire of 25 μmφ, I
After connecting the bonding pad on the C chip and the connecting portion between the recording electrode and the connector electrode, the area around the IC chip is covered with a silicone resin to form a coating film,
Finally, the polyimide film which has undergone these various processing steps was cut into a predetermined size corresponding to one unit of the head and divided into each unit to obtain a head main part. The yield in wire bonding at this time was 100%, and reliable wire connection could be performed.

Then, the head main part 5 is adhered to a silicone rubber support 6 having a rubber hardness of 30 and a thickness of 4 mm by a silicone adhesive, and then the back side of the rubber support 6 is thickened. Adhesion on an aluminum base material 7 having a size of 30 mm, a print width of 80 mm, and a resolution of 12 dots / m
A m recording head was prepared. The bump portion of the recording electrode of this recording head has a plane size of 56 μm × 52.
The protrusion height was 20 μm from the surface of the insulating protective layer, and the protrusion shape was 20 μm.

Using the recording head thus obtained, printing and recording were carried out under the same conditions as in Example 1 except that the ink ribbon for current transfer was brought into pressure contact at a linear pressure of 300 g / cm, the applied voltage was 8 V and the pulse width was 1.0 msec. Then, the same various measurements as in Example 1 were performed. The results are shown in Table 1. Using this recording head, a recording electrode (bump portion) was run for 4 km on a pseudo ink medium for an abrasion resistance test, and the same print recording as above was carried out. The print ratio was 98%. It was high and the printing condition was good.

Comparative Example 3 An electric recording head was prepared in the same manner as in Example 1 except that the wire bonding step in Example 1 was performed after the step of bonding and laminating the head main portion and the elastic member. Printing recording and measurement were performed, and the results are shown in Table 1. In this case, the yield in wire bonding is 6
3%, and the connection reliability decreases, and
The printing rate at that time was 42%. In order to investigate the cause of this low printing rate, the current recording head was projected and observed by X-ray, and it was confirmed that the defective connection between the connection portion and the wire in wire bonding was mainly involved.

Example 6 A polyimide precursor was applied to a 20 μm copper foil in a thickness of 15 μm and dried, and then a photoresist was applied to the copper foil surface and dried by heating, and a wiring pattern was exposed and developed and etched. Wiring pattern (wiring pattern of recording electrode: width 85μ
m, pitch 125 μm) and a stabilizing resistor forming gap (gap width: 200 μm) were formed.

Next, masking 2 of a composite material of tantalum and silicon oxide is applied to the cut gap portion of the wiring pattern portion of the recording electrode.
Originally deposited by RF sputtering method, thickness 0.2μm
A stabilizing resistor is provided.

Next, a hole of 60 μm square is formed by a photoresist means by covering a portion 40 μm inside the tip of the wiring pattern portion of the recording electrode with the polyimide front layer, and then plating is grown in this hole portion by a nickel plating step. Then, nickel plating with a thickness of 18 μm is performed, and the connection portion of the recording electrode and the connection portion of the contact electrode are also plated with nickel. Further, tungsten is plated with a thickness of 25 μm on the nickel plating to form the bump portion of the recording electrode. . Next, heat treatment was performed at 300 ° C. for 30 minutes to imidize the polyimide precursor to form a polyimide film layer having a thickness of 7 μm.

Next, in the nickel plating step, the driving IC chip is die-bonded onto the IC mounting pad portion which is thickly formed to a thickness of about 5 μm by nickel plating and is formed at the same time.
The C chip is wire-bonded to the connection part of the recording electrode and the connector electrode part where the hard metal part 15 is provided by stacking and plating tungsten, and then the peripheral area on the IC chip is covered with a silicone resin to perform flexible printing. Completed the circuit (FPC).

This FPC was adhered and laminated on the same silicone rubber member and aluminum support as in Example 1 in the same order, and the printing width as shown in FIG.
An electric recording head of DPI was manufactured. The bump portion of the recording electrode of this recording head has a plane size of 90 μm ×
70 μm, the protrusion height from the polyimide layer surface is 30 μm
It had a convex shape.

Using this recording head, print recording and various measurements were carried out in the same manner as in Example 1 except that the image signal conditions were an applied voltage of 20 V and a pulse width of 0.5 msec. The results are shown in Table 1. Further, using this recording head, after running for 4 km on the pseudo ink medium for the abrasion resistance test of the recording electrodes (bumps), the same print recording as the above was carried out, The printing rate was 98.1%, and most of the printed dots were printed almost uniformly.

[0078]

[Table 1]

[0079]

As described above, in the electric recording head of the present invention, the recording electrodes, the driving circuit and the connector electrodes are integrally provided on the same film base material, and the stabilizing resistor is provided for each recording electrode. Since the cutting gaps formed in the respective wiring patterns are filled with the resistor material, the structure is small and simple. Further, the stabilizing resistor can be easily provided during the process of forming the main part of the head, and is particularly simpler if the stabilizing resistor is not an integral shape continuous between the wiring pattern portions of the recording electrodes. Will be possible.

Further, since the stabilizing resistor as described above is provided in the main part of the head, even if the image signal current from the drive circuit driven by a constant voltage changes instantaneously for some reason, the change is reduced. As a result, an accurate and stable energization (heat generation) state with the print recording medium is secured, and uniform and stable high-resolution image printing is possible over the entire area in the head width direction. This effect is more remarkable in the case of the structure in which the main part of the head is laminated on the rigid support via the elastic member, the contact stability of the recording electrode with respect to the surface of the print recording medium is excellent, and the printing dot omission does not occur. Become.

Further, by the respective constitutions of the main part of the head and the stabilizing resistor which are integrally formed as described above and the combination thereof, it is easy to increase the length, and disconnection or short circuit due to vibration or the like may occur. It is easy to mass produce. As a result, it is possible to provide an inexpensive recording head having a wide printing width and excellent printing characteristics and durability.

[Brief description of drawings]

1A and 1B show an embodiment of an electric recording head according to the present invention, in which FIG. 1A is a plan view thereof, and FIG.
It is a -b line sectional view.

FIG. 2 is a process drawing showing an example of the manufacturing method of the present invention.

FIG. 3 is a schematic cross-sectional view showing a state of electric recording by the electric recording head of the present invention (without integrally formed return path electrode).

FIG. 4 is a schematic cross-sectional view showing an energized recording state by an energized recording head provided with an integrally formed return path electrode according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flexible insulating film, 2 ... Recording electrode, 2a ... Wiring pattern part, 3 ... Drive circuit, 4 ... Connector electrode, 5 ... Head main part, 6 ... Elastic member, 7 ... Rigid support body, 12 ... Stable Resistor, 13 ... Return electrode, 15 ... Cutting gap.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B41J 3/20 113 B

Claims (4)

[Claims] 1. A current-carrying recording head for forming an image on a recording paper by bringing a return electrode and a recording electrode into contact with a print recording medium and energizing the recording electrode, a driving circuit and a connector on a flexible insulating film. A stabilizing resistor is formed by integrally arranging the electrodes to form the main part of the head, and filling a cutting gap formed in the wiring pattern part of each recording electrode in the main part of the head with a resistor material. An electric recording head characterized by being provided. 2. The current-carrying recording head according to claim 1, wherein the stabilizing resistor has an integral shape continuous between the wiring pattern portions of the recording electrodes. 3. The electric recording head according to claim 1 or 2, wherein a main part of the head is laminated on a rigid support through an elastic member. 4. The current-carrying recording head according to claim 1, wherein a return path electrode capable of contacting the print recording medium is integrally provided.