JPH06171092A - Thermal ink jet head - Google Patents

Abstract

PURPOSE:To provide a thermal ink jet head capable of performing stable injection even in the case of having dust entered into the head. CONSTITUTION:On a heater wafer 2 having a plurality of heat resistors 6 formed thereon, a polyamide layer is laminated, and a common bypass bit 9 is formed for connecting a plurality of bits 7 defining bubble forming areas on the polyimide layer 3, a plurality of individual bypass bits 8, and nozzles. A head is constructed by sticking a plurality of the nozzles 4 and a channel wafer 1 formed with an ink reservoir through ODE thereon. As dust is trapped in the individual bypass bits 8, ink is supplied from adjacent nozzles via the common bypass bits 9 for connecting interstices between the nozzles, thereby replenishing ink to the nozzles contaminated by dust in ink flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ink flow path of a thermal ink jet head.

[0002]

2. Description of the Related Art Conventionally, a heater substrate having a bubble generating resistor, a plurality of nozzle channels, an ink reservoir,
A thermal inkjet head composed of a channel substrate having a supply port is used. In such a conventional thermal ink jet head, as a method for forming an ink flow path, for example, as disclosed in JP-A-61-230954, a nozzle is formed by using anisotropic etching on a Si substrate. , Methods of forming ink reservoirs are known. In this example, after the nozzle and the ink reservoir are formed, they are connected by a groove formed by dicing. However, since the length of the nozzle cannot be accurately controlled by dicing, for example, in Japanese Unexamined Patent Publication No. 1-148560, the nozzle portion and the ink reservoir are formed as independent grooves, respectively, and polyimide is provided between them. A means for connecting by a concave portion (bypass portion) provided on the side is used.

FIG. 4 is an exploded perspective view showing the structure of a conventional thermal ink jet head, and FIG. 5 is a sectional view of the same. In the figure, 1 is a channel wafer, 2 is a heater wafer, 3
Is a polyimide layer, 4 is a nozzle, 5 is an ink reservoir, 6
Is a heating resistor, 7 is a pit, 8 is an individual bypass pit,
Reference numeral 11 is a filter, and 12 is an ink supply pipe. A plurality of nozzles 4 and one ink reservoir 5 are formed on the channel wafer 1. The ink reservoir 5 penetrates the channel wafer 1, and an ink supply pipe 12 is connected to an opening on the upper surface of the channel wafer 1 as shown in FIG. 5, and ink is supplied via a filter 11. The heater wafer 2 has a plurality of heating resistors 6 corresponding to each nozzle.
Are formed. Further, the polyimide layer 3 is laminated on the heater wafer 2. In the polyimide layer 3, a pit 7 is formed on the heater wafer 2 above the heating resistor 6. Further, individual bypass pits 8 for connecting the respective nozzles 4 formed in the channel wafer 1 and the ink reservoir 5 are formed. The channel wafer 1 and the heater wafer 2 on which the polyimide layer 3 is laminated are adhered to each other to form an integrated thermal inkjet head. A cross-sectional view of the thermal inkjet head thus produced is shown in FIG. The ink supplied from the ink supply pipe 12 is removed of dust in the ink by the filter 11 and enters the ink reservoir 5. The ink in the ink reservoir 5 is supplied to the nozzle 4 via the individual bypass pit 8. Bubbles are generated in the pits 7 due to the heat generated by the heat generating resistor 6, and the generated bubbles cause ink in the nozzles to be ejected from the openings of the nozzles for recording.

In such a conventional thermal ink jet head, in the individual bypass pits 8 formed in the thin polyimide layer 3, the ink flow path is narrow and bent, so that dust in the ink is collected in this portion. Cheap. In the conventional thermal ink jet head as described above, since one nozzle corresponds to one bypass flow path, if the dust is clogged, the ink supply to the nozzle is hindered, and the repeated ejection characteristic of the nozzle is deteriorated. As a result, an injection failure occurs such that the injection drop becomes small or the injection cannot be performed at all.

As shown in FIG. 4, a method of forming a filter 11 upstream of an ink flow path is also used, but the filter is expensive, dust generated during assembly, and dust existing in the flow path from the beginning. Since there is no effect on, the sufficient effect was not obtained. On the other hand, it is extremely difficult to eliminate dust that is mixed in the head in the ink or in the manufacturing process, and some dust is stochastically mixed.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a thermal ink jet head capable of performing stable ejection even if dust is mixed in the head. It is what

[0007]

The present invention provides a thermal ink jet head comprising a heater substrate having a bubble generating resistor and a channel substrate having a plurality of nozzle channels, ink reservoirs, and supply ports. A resin layer is provided on the resin layer, and a plurality of individual bypass sections that individually connect the ink reservoir and the nozzle flow path to the resin layer are provided between the plurality of individual bypass sections and the bubble generating resistor. It is characterized in that one or a plurality of common bypass parts for connecting a plurality of nozzle channels are provided.

[0008]

According to the present invention, even if dust is accumulated in the individual bypass portion corresponding to the original nozzle and obstructs the ink flow, the ink is removed from the surrounding nozzles through the common bypass portion provided in the resin layer. The ink can be supplied, the deterioration of the ejection characteristics can be suppressed, and stable ink ejection can be performed.

[0009]

1 is an exploded perspective view showing an embodiment of a thermal ink jet head of the present invention, and FIG. 2 is a sectional view of the same. In the figure, the same parts as those in FIGS. 9 is a common bypass pit and 10 is garbage.

Similar to the conventional thermal ink jet head, a polyimide layer 3 as a resin layer is laminated on a heater wafer 2 made of a Si substrate on which a plurality of heating resistors 6 are formed, and a bubble forming region is formed on the polyimide layer 3. A plurality of prescribed pits 7 and a plurality of individual bypass pits 8 are formed. At this time, a groove is formed so as to connect the nozzles to each other to form the common bypass pit 9. A plurality of nozzles 4 and an ink reservoir 5 are bonded to a channel wafer 1 made of a Si substrate formed by anisotropic etching.

As shown in FIG. 2, the ink flow reaches the nozzle 4 from the ink reservoir 5 through the individual bypass pit 8. Here, as described above, the individual bypass pit 8 is bent and has a narrow cross-sectional area, and when the dust 10 is trapped, the ink flow becomes poor, the ink supply to the nozzle becomes insufficient, and small dots are formed. This may cause ejection failure such as misjet. In such a case, adjacent nozzles or, via the common bypass pit 9 connecting the nozzles, or
By supplying ink from nearby nozzles, dust 1
When 0, it is possible to supplement the ink supply to the nozzle where the ink flow has deteriorated, and it is possible to suppress the ink supply shortage to a minor level that cannot be perceived as the actual image quality.
On the contrary, since the dust 10 can be wrapped with the individual bypass pits 8, it is possible to prevent the dust 10 from being clogged with the nozzles 4 and causing an ejection failure.

In FIG. 1, the common bypass pit 9 is constructed so that all nozzles are connected by one groove. However, if it is constructed so as to connect a plurality of nozzles, it will be possible to connect a plurality of nozzles to each nozzle. The common bypass pit 9 can be configured by the plurality of grooves provided. For example, when a driving method in which several adjacent nozzles are not driven at the same time is adopted, it is possible to drive several nozzles that are not driven simultaneously by connecting them with a common bypass pit 9. It is possible to reduce the crosstalk that occurs between the generated nozzles. However, since it is possible that dust 10 may accumulate in the individual bypass pits 8 corresponding to a plurality of nozzles, it is desirable to connect as many nozzles as possible with the common bypass pit 9. Crosstalk can be reduced to some extent by increasing the distance between the pit 7 and the common bypass pit 9 as much as possible.

It is also possible to provide a plurality of common bypass pits 9. FIG. 3 is an exploded perspective view showing another embodiment of the thermal inkjet head of the present invention. In FIG. 3, as described above, all nozzles are connected by a plurality of common bypass pits 9 and a plurality of rows of common bypass pits are provided. For example, as described above, several nozzles that are not driven at the same time may be connected by a common bypass pit on the pit 7 side, and these sets may be connected by a common bypass pit on the ink reservoir side. With the configuration of the common bypass pit 9 as shown in FIG. 3, all the nozzles are connected by the two rows of the common bypass pit 9, and even if the individual bypass pit 8 is clogged with dust, the ink is supplied from the nearby nozzles. Can be received. Of course, it is also possible to form the common bypass pit by two grooves that connect all the nozzles. Further, in the above-mentioned configuration, the common bypass pit 9 is provided orthogonally to the nozzle 4, but it may be provided, for example, obliquely, and the common bypass pit 9 may be formed by other shapes, arrangements, and grooves of different numbers. Can be formed.

[0014]

As is apparent from the above description, according to the present invention, even if dust is retained in the individual bypass portion corresponding to the original nozzle and obstructs the ink flow, the common bypass provided in the polyimide is provided. Ink can be supplied from the surrounding nozzles through the section, deterioration of ejection characteristics can be suppressed, and stable ink ejection can be achieved. Further, the individual bypass section functions as a filter, and it is possible to prevent the nozzle from being clogged even with dust generated during head production, and to obtain stable characteristics regardless of the processing environment. The effect is that you can. At this time, since it is not necessary to separately provide a filter, there is an effect that an inexpensive recording device can be manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a thermal inkjet head of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of the thermal inkjet head of the present invention.

FIG. 3 is a perspective view showing another embodiment of the thermal inkjet head of the present invention.

FIG. 4 is a perspective view showing a configuration of a conventional thermal inkjet head.

FIG. 5 is a sectional view showing a configuration of a conventional thermal inkjet head.

[Explanation of symbols]

1 channel wafer, 2 heater wafer, 3 polyimide layer, 4 nozzles, 5 ink reservoir, 6 heating resistor, 7 pit, 8 individual bypass pit, 9 common bypass pit, 10 dust, 11 filter, 12 ink supply pipe.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kozo Hosogai, 2274 Hongo, Ebina, Ebina, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor, Yutaka Mori, 2274, Hongo, Ebina, Ebina, Kanagawa (72) Inventor Masahiko Fujii 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (1)

[Claims] 1. A thermal ink jet head comprising a heater substrate having a bubble generating resistor and a channel substrate having a plurality of nozzle channels, ink reservoirs, and supply ports, wherein a resin layer is provided on the heater substrate. A plurality of individual bypass parts that individually connect the ink reservoir and the nozzle flow path to the resin layer, and connect a plurality of nozzle flow paths that are provided between the plurality of individual bypass parts and the bubble generating resistor A thermal ink jet head, characterized in that it is provided with one or more common bypass sections.