JPH0243059A - Protective structure for electronic parts of printing head - Google Patents

Abstract

PURPOSE:To certainly protect electronic parts, to facilitate the control of a seal material and to also suitably avoid the deformation of a substrate or lead wire by indivisually covering the respective electronic parts provided on the substrate of a printing head is parallel with a seal material. CONSTITUTION:Resistance heating parts 5 consisting of a large number of heating resistors are provided to the upper end part of an alumina substrate 2 in the vicinity of the free end part thereof so as to extend in a left-and-right direction and driver ICs 6 for selectively driving a large number of heating resistors to generate heat are provided in the vicinity of the close contact part 9 with the resin substrate 3 on the alumina substrate 2 so as to extend in parallel to the extending direction of the resistance heating parts 5. Indivisual electrodes 7 are arranged between the respective resistance heating parts 5 and the respective corresponding driver ICs 6 and connected to the driver ICs 6 by lead wires 10 and one terminal parts of the wirings 18 connected to an external circuit are also connected to said ICs 6 by lead wires 11. The respective driver ICs 6 are indivisually covered with a seal material 12 composed of an epoxy resin.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is for sealing electronic components such as a driver IC mounted on a substrate of a printer head such as a thermal head or an LED array head with a sealing material. The present invention relates to a structure for protecting electronic components of a printer head.

<Prior Art> Conventionally, thermal line technology has been used to perform desired printing by sliding a resistance heating section of a thermal head extending in the width direction of paper supported by a platen onto the paper surface via a thermal transfer ink ribbon. Printers are known. The above-mentioned thermal head has multiple electronic components such as driver ICs that selectively generate heat in the resistive heating section mounted in parallel on its substrate, and these electronic components are sealed with silicone resin to protect them from external disturbances. I tried to cover it comprehensively with wood. Furthermore, since silicone resin is relatively soft, a metal cover is provided above the sealing material to physically protect the electronic components.

On the other hand, an LED in which multiple LED arrays are arranged in parallel on a substrate
The LED array head of a line printer is also equipped with multiple driver ICs in parallel that selectively light up the LED elements of each array, and is equipped with a sealing material made of silicone resin and a metal cover, similar to the thermal head described above. I was trying to set up a .

However, in order to comprehensively cover multiple electronic components mounted in parallel with silicone resin, first form the outer shell with high-viscosity silicone resin, and then pour low-viscosity silicone resin inside. However, the management of these two types of sealing materials has become complicated and the number of man-hours for sealing work has tended to increase.

Therefore, by using an epoxy resin as the sealing material, it is possible to use only one type of sealing material, which facilitates its management and reduces the number of steps required for sealing work.

Furthermore, since the epoxy resin becomes relatively hard after curing, there is no need to provide a separate metal cover.

However, because the lead wires extending from the board or electronic components and the encapsulant made of the epoxy resin have different coefficients of thermal expansion, the board may deform or the lead wire may Problems may arise in terms of durability, etc.

<Problems to be Solved by the Invention> In view of the problems of the prior art as described above, the main object of the present invention is to provide a method that can suitably protect electronic components provided on a substrate of a printer head and also improve the ease of handling. An object of the present invention is to provide a simple protection structure for electronic components of a printer head.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, such an object includes a plurality of heat-generating electric elements arranged in parallel on a substrate of a printer head, and a method for selectively exciting the elements. 1. An electronic component protection structure for a printer head having a plurality of electronic components mounted in parallel on a substrate in order to protect the electronic components, wherein each of the electronic components is individually covered with a sealing material. This is achieved by providing a protective structure for electronic components. The heating electric element may be a resistive heating element film of a thermal head or an LED element of an LED array head.

<Function> In this way, it is possible to reliably protect the multiple electronic components mounted in parallel on the substrate of the printer head, it is also easy to manage the sealing material, and deformation of the substrate and lead wires can be suitably avoided. can do.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a first embodiment according to the invention. Thermal line head 1, which faces the printed surface of paper (not shown) via a thermal transfer ink ribbon, has an alumina substrate 2 provided on its free end side, that is, the upper side in FIG. It has a resin substrate 3 provided on its lower side, and a heat sink 4 that is in close contact with the bottom of these substrates 2.3, as shown in FIG. Near the free end of the alumina substrate 2, that is, at the upper end in FIG. 1, a resistance heating section 5 consisting of a large number of resistance heating elements extends in the left-right direction. Further, in the vicinity of the close contact portion 9 with the resin substrate 3 on the alumina substrate 2, a driver IC 6 for selectively generating heat from the plurality of resistance heating elements is provided extending parallel to the extending direction of the resistance heating portion 5. has been done. Individual electrodes 7 are disposed between each resistance heating section 5 and the corresponding driver IC 6. These individual electrodes 7 and driver IC 6 are
As shown in the figure, they are connected by lead wires 10. Each driver IC 6 is also connected to one end of a wiring 8 connected to an external circuit using a lead wire 11. Note that a common electrode (not shown) is provided in the resistance heating section 5.

Each driver IC 6 is individually covered with a sealing material 12 made of epoxy resin applied by a coating device (not shown), so as to be protected from external disturbances.

Therefore, unlike the case where a plurality of driver ICs 6 are comprehensively covered with resin, the side substrate 2.3 and the lead wires 10.
11 and the sealing material 12 due to the difference in coefficient of thermal expansion.
3 and both lead wires 10.11 can be avoided.

Here, as clearly shown in FIG. 2, since the driver IC 6 is provided near the abutting part 9 between the alumina substrate 2 and the resin substrate 3, the sealing is performed so as to cover this abutting part 9 as well. Since the resin material 12 is applied, air may enter the sealing material 12 from the butt part 9, but by separately filling the butt part 9 with a resin material, airtightness is ensured and the seal is sealed. The inside of the material 12 can be suitably sealed.

3 and 4 are views similar to FIGS. 1 and 2, showing a second embodiment based on the present invention.

According to this embodiment, the sealing materials 15a and 16a made of epoxy resin are applied to the lead wires 1 of the driver IC 6 using the pair of application nozzles 14a and 14b shown by phantom lines in FIG.
It is applied only to the area where 0.11 is placed. Therefore, compared to the first embodiment, the thermal expansion coefficients of the side substrate 2.3 and lead wires 10.11 and the sealing materials 15a, 15b are
It is possible to more preferably avoid the influence on the side substrate 2.3 and both lead wires 10.11 due to the difference in coefficient of thermal expansion between the two lead wires 10.11 and the amount of epoxy resin used.

5 and 6 are diagrams similar to FIGS. 1 and 2 showing a third embodiment based on the present invention.

In this embodiment, a driver IC 6 is mounted on the middle part of the alumina substrate 2, and the IC has lead wires 10 and 11 attached to individual electrodes 7 disposed on the alumina substrate 2.
and is connected to one end of the wiring 16. The other end of the wiring 16 is connected to the flexible cable 1 connected to an external circuit.
7 and is pressed from above through a silicone rubber 18 by a pressing plate 19 screwed to the heat sink 4 through a collar. These driver IC 6 and lead wires 10 and 11 are individually covered with a sealant 21 made of epoxy resin. Incidentally, reference numeral 20 is a spacer for preventing deformation of the flexible cable 17. The rest of the configuration is the same as the first embodiment.

According to this embodiment, since the driver IC 6 is mounted in the middle part of the alumina substrate 2, air does not enter the part covered by the sealing material 21 from the outside.

7 and 8 show a fourth embodiment based on the present invention. In this embodiment, a protection structure based on the present invention is applied to an LED array head of an LED line printer.

The LED array head 31 includes a heat sink 32 made of metal and an alumina substrate 33 mounted on top of the heat sink 32. Mounted on the alumina substrate 33 are an LED array chip 34 and a driver IC 35 whose corresponding parts are connected to each other by lead wires. Also,
The driver IC 35 is also connected by a lead wire to one end of a wiring 36 formed on the proximal end side of the alumina substrate 33, that is, on the lower side in FIG. The other end of the wiring 36 is
A pressure contact plate 39 is in contact with one end of a flexible cable 37 connected to an external circuit and screwed onto the heat sink 32 from above through a spacer 38.
It is pressed through silicone rubber 40. Furthermore, L
A common electrode 41 provided at the bottom of the ED array chip 34
is connected to a flexible cable 37 via both left and right end portions shown in FIG. Note that the free end portion of the alumina substrate 33 is fixed to the heat sink 32 via a pressure contact plate 45 screwed to the heat sink 32 via a spacer 43 via a silicon rubber 44 around which copper foil is wrapped.

Each of these driver ICs 35, the lead wires extending from the ICs, and the portions of the LED array chips 34 corresponding to the driver ICs 35 excluding the light emitting windows 34a are individually covered with a sealing material 46 made of epoxy resin.

9 to 12 show fifth to eighth embodiments based on the present invention, and are plan views schematically showing the arrangement of a driver IC and a sealing material in a thermal head or an LED array head. It is.

In FIG. 9 showing the fifth embodiment, in a line head with a high resolution of, for example, 240 DPI or more, drivers 1c47 are arranged in a staggered manner in two rows, each with a sealing material 4 made of epoxy resin.
It is sealed at 8.

In FIG. 10 showing the sixth embodiment, a plurality of line head driver ICs 49 are mounted vertically so that their longitudinal directions are perpendicular to the longitudinal direction of the printer head, and each is sealed with an epoxy resin. It is sealed with a material 50.

In FIG. 11 showing the seventh embodiment, for example, in a thermal serial head, two driver ICs 51 are arranged in parallel and each is sealed with a sealant 52 made of epoxy resin.

In FIG. 12 showing the eighth embodiment, in a serial head similar to the seventh embodiment, two driver ICs 53 are arranged diagonally in parallel, and each is sealed with a sealant 54 made of epoxy resin. are doing.

In addition, in the above example, epoxy resin was used as the sealing material, but
It goes without saying that the material is not limited to this, and for example, phenol resin, polyimide resin, etc. may be used.

[Effects of the Invention] As described above, according to the present invention, by individually sealing each of the plurality of electronic components provided in parallel on the substrate of the printer head, it is possible to seal the electronic components without impairing the protection effect of the electronic components. In addition, problems such as deformation of the substrate of the thermal head or LED array head due to the difference in thermal expansion coefficient between the sealing material and the substrate or the sealing material and the lead wire, resulting in deterioration of printing performance, are no longer caused. For example, since a relatively hard resin can be used as a sealing material for the head, there is no need to use a separate metal cover, and the number of parts can be reduced.
Sealing work efficiency improves. Furthermore, attachment and detachment work, such as when replacing mounted and sealed electronic components, becomes easier. From the above, the effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the main parts of a thermal line head to which a protection structure according to the present invention is applied. FIG. 2 is an enlarged sectional view taken along the line ■--■ in FIG. 3 and 4 are views similar to FIGS. 1 and 2, showing a second embodiment based on the present invention. FIGS. 5 and 6 are views similar to FIGS. 1 and 2, showing a third embodiment based on the present invention. FIG. 7 is a plan view showing a main part of an LED array line head to which a protection structure according to the present invention is applied. FIG. 8 is an enlarged sectional view taken along the line ■--■ in FIG. 7. 9 to 12 show fifth to eighth embodiments based on the present invention, and are schematic plan views showing only a driver IC and a sealing material of a thermal head or an LED array head. 1...Thermal line head 2...Alumina board 3...Resin board 4...Heat sink 5...
・Resistance heating part 6...Driver IC7...Individual electrode 8...Wiring 9...Butt part 1
0.11... Lead wire 12... Sealing material 14a, 14b... Application nozzle 15a, 15 b... Sealing material 16... Wiring 17... Flexible cable 18... Silicon rubber 19...pressure plate 20...
Spacer 21... Sealing material 1... LED array head 2... Heat sink 33... Alumina substrate 4...
・LED array chip 4a...window 35...driver IC6...
・Wiring 7...Flexible cable 8...Spacer 39...Pressure plate 0...Silicon rubber 41...Common electrode 3...Spacer
44... Silicone rubber 5... Pressure contact plate 46
... Sealing material 7.49.51.53 ... Driver IC
8, 50, 52, 54... Sealing material

Claims (3)

[Claims] (1) Electronic components for a printer head that include a plurality of heat generating electric elements arranged in parallel on the substrate of the printer head and a plurality of electronic components mounted in parallel on the substrate to selectively excite the elements. 1. A protective structure for protecting electronic components of a printer head, wherein each of the electronic components is individually covered with a sealing material. (2) The electronic component protection structure for a printer head according to claim 1, wherein the heat generating electric element is made of a resistive heating element film. (3) The electronic component protection structure for a printer head according to claim 1, wherein the heat generating electric element is an LED element.