AU720417B2

AU720417B2 - Ink jet recording head and apparatus

Info

Publication number: AU720417B2
Application number: AU51088/98A
Authority: AU
Inventors: Eiichiro Shimizu
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1994-08-24
Filing date: 1998-01-09
Publication date: 2000-06-01
Anticipated expiration: 2015-08-23
Also published as: AU5108898A

Description

S F Ref: 311403D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Canon Kabushiki Kaisha 30-2, Shimomaruko 3-chome Ohta-ku Tokyo 146

JAPAN

Actual Inventor(s): Address for Service: Invention Title: Eiichiro Shimizu Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Ink Jet Recording Head and Apparatus The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845 A INK JET RECORDING HEAD AND APPARATUS FIELD OF THE INVENTION AND RELATED ART The present invention relates to an ink jet recording head which records images by means of ejecting ink onto a piece of recording medium, and also to an ink jet recording apparatus comprising such an ink jet recording head. In this case, the terminology "record" means to "apply" the ink or the like to any ink receptive medium which includes fabric, yarn, paper, sheet material of various types, and the "recording apparatus" means an information processing apparatus itself inclusive of printer, or the printer itself as the output device, to which the 15 present invention is applicable.

Among various types of presently known recording systems, the ink jet recording system has been recognized as an extremely effective recording .*.system, since it is a non-impact recording system 20 which generates little noise during recording; it is capable of recording at a high speed; and in addition, it is capable of recording on plain paper without requiring a special fixing process.

Figures 15 and 16 illustrate the essential portions of a typical ink jet recording head employed in such an ink jet recording system. Figure 15 is a schematic perspective view thereof, and Figure 16 is '3 -2an exploded perspective view thereof. Figure 17 is a schematic sectional view of the internal structure of the ink jet recording head, at sectional plane X-X.

Reference numeral 100 designates a base plate, on which various components (which will be described later) are constructed. On this base plate 100, a piece of substrate 200 (hereinafter, a heater board) is disposed, which comprises a plurality of electrothermal transducers (heaters) 201 as elements for ejection energy. On this heater board 200, an ink path (not illustrated) leading to a plurality of ink ejecting orifices 301 is located, and also, to a predetermined point thereof, a top plate 300 is joined. The top plate 300 comprises: an orifice plate 304 with the ink ejection orifices 301; a common liquid chamber 302 for storing the ink to be supplied eoooo through the aforementioned ink path; and a cylindrical ink inlet pipe for supplying the ink to this common liquid chamber 302. The top plate 300 is joined with the heater board 200 in the following manner. First, the top plate 300 is temporarily glued onto the heater board 200, in such a manner that the plurality of heaters 201 of the heater board 200 become aligned with the correspondent ink ejection orifices 301 of the top plate 300, and then, a mechanical pressure is applied, from above, to the top plate 300, with the use of a spring (unillustrated), so that two -3components can be satisfactorily joined in an airtight manner. Thereafter, the peripheries of the top plate 300 and heater board 200 are sealed with sealant 400 as shown in Figure 17, whereby the ink path and common liquid chamber 302 are airtightly sealed.

It is well-known that liquid chamber partitioning walls 303 are disposed on the heater board 200 so as to form the common liquid chamber 302 on the inward facing surface of the heater board 200 (Japanese Laid-Open Patent Application No.

101,958/1991, or the like).

Recently, however, the size of the heater board has been progressively reduced in order to reduce the size of the ink jet recording head as well as the heater board cost. As the results of this size reduction, there have been cases in which it is difficult, in terms of space, to form the liquid chamber walls on the inward facing surface of the .*.heater board in a conventional manner. In addition, S 20 the reduced size of the heater board results in a reduced distance between the heater board edge and the eeeee :::outermost ink ejection orifice, and as a result, the sealant for sealing the common liquid chamber is liable to flow sometimes into the ink ejection orifices, creating thereby such a problem that the ink cannot be ejected.

Summary of the Invention In accordance with one aspect of the present invention, there is provided an ink jet recording head comprising: a top plate having recesses for forming laterally adjacent ink paths connected to a plurality of ejection outlets from which ink is ejected; a substrate for forming the ink paths by joining it with said top plate, with the recesses facing inward; 6 6 .6 [R:\LIBE]02745.docavc wherein said top plate comprises lateral overhanging portions which overhang from an edge of said substrate in the direction of a thickness of said substrate, the joint between said top plate and said substrate being sealed with a sealant, and the lateral overhanging portions of said top plate are provided with an opening.

6 o **o o

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S o ••o [R:\LIBE]02745 docavc Brief Description of the Drawings Figure 1 is a schematic perspective view of the essential portions of the first embodiment of the ink jet recording head in accordance with the present invention.

Figure 2 is an exploded perspective view of Figure 1.

Figure 3 is a schematic perspective view of the internal structure of the top plate of the first S* a.

[n:\libE]01139:VXF

V

-7embodiment of the ink jet recording head in accordance with the present invention.

Figure 4 is the sectional view of Figure 1, at sectional plane X-X.

Figure 5 is a schematic perspective view of the essential portions of the second embodiment of the ink jet recording apparatus in accordance with the present invention.

Figure 6 is an exploded perspective view of Figure Figure 7 is a schematic perspective view of the internal structure of the top plate in the second embodiment of the ink jet recording apparatus in accordance with the present invention.

.9 15 Figure 8 is a sectional view of Figure 5, at 9999 sectional plane X-X.

:Figure 9 is a schematic perspective view of the essential portions of the third embodiment of the "ink jet recording apparatus in accordance with the 9*° present invention.

Figure 10 is a schematic perspective view of "the internal structure of the top plate in the third embodiment of the ink jet recording head in accordance with the present invention.

Figure 11 is a sectional view of Figure 9, at sectional plane X-X.

Figure 12 is a schematic perspective view of -8the essential portions of the fourth embodiment of the ink jet recording head in accordance with the present invention.

Figure 13 is a schematic perspective view of the internal structure of the top plate in the fourth embodiment of the ink jet recording head in accordance with the present invention.

Figure 14 is a schematic perspective view of an embodiment of the ink jet recording apparatus in accordance with the present invention.

Figure 15 is a schematic perspective view of the essential portions of a typical, conventional ink jet recording head.

Figure 16 is an exploded perspective view of 15 the essential portions of the typical, conventional ink jet recording head.

SFigure 17 is a schematic sectional view of the internal structure of the ink jet recording head of Figure 15, at sectional plane X-X.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the embodiments of the present invention will be described in detail referring to the .drawings.

Embodiment 1 Figures 1 4 depict the first embodiment of the ink jet recording apparatus in accordance with the -9present invention, wherein Figure 1 is a schematic perspective view of the essential portions thereof,; Figure 2, an exploded perspective view of Figure 1; Figure 3, a schematic perspective view of the internal structure of the top plate; and Figure 4 is a sectional view of Figure i, at sectional plane X-X.

Among the structural components in this embodiment, those common to the conventional ink jet recording head illustrated in Figures 15 17 will be designated with the same references, and their descriptions will be omitted.

This embodiment is characterized in that the common liquid chamber wall 303 overhangs from the heater board 200, at both edges in the direction in 15 which the plurality of heaters 201 are aligned on the 0e •go• heater board 200 as the element substrate, that is, in *0000S 0oo S the direction in which the ejection orifices are aligned. This arrangement makes it possible to *"minimize the space occupied on the upward facing surface of the heater board 200 by the liquid chamber wall 303, that is, the portions involved to join the *000 &fe liquid chamber wall 303 and heater board 200; therefore, it is possible to reduce the heater board 0060 .200 size. Referring to Figure 4, it is preferable that the relationship between width m, which is the width of the heater board 200 in the direction in which the plurality of heaters 201 are aligned, and width i, which is the width of the common liquid chamber 302 in the same direction, satisfies the following formula: m i. More specifically, the difference between m and 1 in this embodiment was set at 0.1 mm. Parenthetically, when the head was constructed with the relationship being: m i, there was a problem in that the sealant flowed onto the upward facing surface of the heater board, and also into the ink ejection orifices 301.

Also, this embodiment is characterized in that projection 306 is provided on the top plate 300, behind the common liquid chamber 302, relative to the ejection orifice plate 304, as shown in Figure 3. The common liquid chamber 302 is constituted of a recess 15 formed in a surface of the top plate 300. In one of the lateral walls of the common liquid chamber 302, a plurality of ink passages 308 are formed in such a manner that each passage is correspondent to one of the plurality of ink ejection orifices 301 formed in -the orifice plate 304, connecting thereby the common liquid chamber 302 and the ink ejection orifices 301.

The aforementioned projection 306 is at the center portion of the opposite common chamber wall of this same common liquid chamber wall, in which the ink passages 308 are formed. The upward facing surfaces of the walls 303 of the common liquid chamber 302 constitute the surfaces to be joined with the heater -11board 200 of the top plate 300, but since the projection 306 is on one of these upward facing surfaces, the joint is actually constituted of the top surface of this projection 306, and the top surfaces of the plurality of the ink passage walls 307 that form the aforementioned plurality of ink passages 308.

Therefore, the mechanical pressure applied to the top plate 300 by the leaf spring 401 is concentrated toward the ink passage walls 307. After the spring 401 is fitted, the peripheries of the top plate 300 and heater board 200 are sealed with the sealant 400 as shown in Figure 4, and at this time, the sealant .*.400 invades into slight gaps formed by the projection 306, between the heater board 200 and common liquid 15 chamber walls 303, and seals them airtightly. Since no gap is formed between the ink passage walls 307 and heater board 200, the sealant 400 externally seals the joint between the top plate 300 and heater board 200.

In this embodiment, the height of the projection 306 from the top surface of the common liquid chamber wall 303 is within a range of 5 pm. When it is no more than 5 pm, the satisfactory adhesion cannot be effected between the heater board 200 and ink passage walls 307, and when it is no less than 20 pm, the gap between the liquid chamber wall 303 and heater board 200 becomes excessively large, creating thereby a problem occasionally in that the

I

-12sealant 400 flows onto the top surface of the heater board 200, and also into the ink ejection orifices.

Embodiment 2 Figures 5 7 illustrate the second embodiment of the ink jet recording head in accordance with the present invention. Figure 5 is a schematic perspective view of the essential portions thereof; Figure 6, a schematic perspective view of the internal structure of the top plate; and Figure 7 is a sectional view of Figure 5, at sectional plane X-X.

Also in this embodiment, the structural components common to the conventional ink jet recording head illustrated in Figures 15 17, and also to preceding ".embodiment, are designated with the same references, 15 and their descriptions will be omitted.

This embodiment is characterized in that the heater board 200 is disposed between the opposing two walls 303a of the common liquid chamber 303 of the top plate 300, which extend in the direction perpendicular to the alignment direction of the plurality of ink ejection orifices 301 of the orifice plate 304. The ::liquid chamber walls 303a extend far beyond the top surfaces of the liquid chamber walls 303 as shown in Figure 7, and function, like a dam, to prevent the invasion of the sealant 400 used to seal externally the common liquid chamber 302 of the top plate 300.

As for the amount of the projection of the liquid

I

-13chamber wall 303a in this embodiment, it is set to be less than the thickness of the heater board 200. This is because, if the amount of the projection is set to be more than the thickness of the heater board 200, the sealant 400 cannot be successfully prevented from flowing into the common liquid chamber 302, and also, in some cases, the interface between the ink passage walls 307 and heater board 200 cannot be satisfactorily sealed.

Thus, this embodiment enjoys the following effects in addition.to those of the preceding embodiment. That is, the sealant 400 is reliably .*.prevented from flowing into the common liquid chamber 302, so that the ink ejection orifices 301 do not S• 15 become plugged up with the sealant 400; therefore, the ink can be reliably ejected to record high quality C-C*images.

Embodiment 3 Figures 9 11 depict the third embodiment of 20 the ink jet recording apparatus in accordance with the present invention, wherein Figure 9 is a schematic perspective view of the essential portions thereof; Figure 10, a schematic perspective view of the internal structure of the top plate; and Figure 11 is a sectional view of Figure 9, at sectional plane X-X.

Also in this embodiment, the structural components common to the conventional ink jet recording head -14illustrated in Figures 15 17, and also to the preceding embodiments, are designated with the same references, and their description will be omitted.

This embodiment is characterized in that not only the projection 306 described in the preceding first embodiment is provided, but also, the heater board 200 is disposed between the opposing two walls 303a of the common liquid chamber 303 of the top plate 300, which extend in the direction perpendicular to the alignment direction of the plurality of ink ejection orifices 301 of the orifice plate 304. The liquid chamber walls 303a extends far beyond the top surfaces of the other liquid chamber walls 303 as "".shown in Figure 11, and function, like a dam, to ol 15 prevent the invasion of the sealant 400 used to seal externally the common liquid chamber 302 of the top plate 300. As for the amount of the projection of the liquid chamber wall 303a in this embodiment, it is set to be less than the thickness of the heater board 200.

This is because, if the amount of the projection is set to be more than the thickness of the heater board 200, the sealant 400 cannot be successfully prevented from flowing into the common liquid chamber 302, and also, in some cases, the interface between the ink passage walls 307 and heater board 200 cannot be satisfactorily sealed.

Thus, this embodiment enjoys the following effects in addition to those of the preceding embodiments.

That is, the sealant 400 is reliably prevented from flowing into the common liquid chamber 302, so that the ink ejection orifices 301 do not become plugged up with the sealant 400; therefore, the ink can be reliably ejected to record high quality images.

Embodiment 4 Figures 12 and 13 depict the fourth embodiment of the ink jet recording apparatus in accordance with the present invention, wherein Figure 12 is a schematic perspective view of the essential portions thereof, and Figure 13 is a schematic perspective view of the internal structure of the top plate. Also in this embodiment, the structural *e [n:\libE]01139:VXF -16components common to the conventional ink jet recording head illustrated in Figures 15 17, and also to the preceding embodiments, are designated with the same alphanumeric references, and their descriptions will be omitted.

This embodiment is characterized in that a pair of notches 309, and opening 310 (cutaway portion), are cut into both of the liquid chamber walls 303a described in the preceding embodiment 3.

The notched portion 309 is positioned away from the orifice plate 304, that is, closer to the liquid chamber wall 303 opposing the ink ejection orifices 301. This notched portion 309 functions to fix temporarily the positional relationship between the 15 heater board 200 and top plate 300, when the two components are joined with adhesive (normally, UVcuring adhesive). The provision of this type of notched portion 309 increases the area of adhesion; therefore, adhesive strength is increased. As for the S. 20 cutaway portion 310, it is formed by means of cutting away a portion of the liquid chamber wall 303a from the top surface of the liquid chamber wall 303a to the top surface of the liquid chamber wall 303. The purpose of this type of cutaway portion 310 is to prevent effectively the adhesive applied to the notched portion 309 for the temporary fixation, from flowing toward the ink ejection orifices 301, and -17plugging them, while the adhesive hardens. Therefore, it is important that this cutaway portion 310 is positioned at the end portion of ink path 308, that is, at the end portion away from the ink ejection orifices 301.

Thus, this embodiment enjoys the following effects in addition to those of the preceding embodiments. That is, not only can the temporary fixation between the heater board 200 and top plate 300 reliably occur with the presence of the notched portion 309 that is cut, as a barrier for preventing the sealant 400 from flowing into the common liquid chamber 302, in the liquid chamber wall 303a, but ***also, the adhesive used for the temporary fixation can S 15 be prevented from flowing into the area of ink 0 ejection orifices 301, by the cutaway portion 310; therefore, the ink ejection orifice 301 is prevented from being plugged up with the adhesive, allowing thereby the ink to be reliably ejected to record high oooeo S20 quality images.

Those ink jet recording heads described in the preceding embodiments of the present invention are mountable in such an ink let recording apparatus as the one illustrated in Figure 14. Figure 14 is a schematic perspective view of an embodiment of the ink jet recording apparatus in accordance with the present invention.

I' i -18- Referring to Figure 14, reference numeral designates a cartridge, which is fixed on carriage with the use of retaining member 81. These are reciprocative in the longitudinal direction of shaft 21 (primary scanning direction). The position of the cartridge 80 on the carriage 15 is fixed by a hole provided in the lid, and a dowel or the like provided on the carriage 15. As for the electrical connection, it is established when a contact pad provided on a wiring substrate is placed in contact with a connector provided on the carriage Recording medium 18 is put through a minute **gap between the recording head and platen 19, and its recording surface is regulated by the platen 19. The oo 15 ink ejected from a recording head reaches the surface of the recording medium 18, where it forms an image.

S To the recording head, ejection signals reflecting image data are sent from an appropriate data source through cable 16 and a terminal connected 20 thereto. The number of cartridge 80 may be one, or two or more, depending on the number of inks, or the colors of the image (two in this drawing).

.ee Also referring to Figure 14, reference numeral 17 designates a carriage motor, which moves the carriage 15 along the shaft 21; 22, a wire for transmitting the driving force of the motor 17 to the carriage 15; and 20 designates a feeder motor, which -19is connected to the platen 19 to feed the recording medium 18.

As for the form of the ink jet recording apparatus to which the present invention is applicable, it may be in the form of an image outputting peripheral device of an information processing apparatus such as a computer. Also, it may be in the form of a copying machine that integrally comprises a reader or the like, and also in the form of a facsimile with both the transmitting and receiving capacities.

While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this Dfe. 15 application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

Claims

1. An ink jet recording head comprising: a top plate having recesses for forming laterally adjacent ink paths connected to a plurality of ejection outlets from which ink is ejected; a substrate for forming the ink paths by joining it with said top plate, with the recesses facing inward; wherein said top plate comprises lateral overhanging portions which overhang from an edge of said substrate in the direction of a thickness of said substrate, the joint between said top plate and said substrate being sealed with a sealant, and the lateral overhanging portions of said top plate are provided with an opening. An ink jet recording apparatus according to Claim 1, wherein said top plate has two such overhanging portions extended in the thickness direction of said 15 substrate, and said substrate is disposed between the lateral overhanging portions. o o

3. An ink jet recording apparatus according to Claim 1, wherein the ink paths comprise a plurality of ink passages connected between said ink ejection outlets and Sa common ink chamber for storing the ink to be supplied to the plurality of ink passages. oooo S4. An ink jet recording head according to Claim 3, wherein a projection is provided at said top plate on a portion of the walls forming the common ink chamber ooeo o: opposite to said plurality of ejection outlets. a.

5. An ink jet recording head according to Claim 1, wherein said top plate integrally comprises an orifice plate in which said plurality of ejection outlets are aligned.

6. An ink jet recording head according to Claim 3, wherein energy generating means for generating the energy to be used for ejecting the ink from said plurality of ejection outlets are disposed along said ink passages.

7. An ink jet recording head according to Claim 6, wherein said energy generating means comprise thermal energy generating members for generating thermal Senergy to create film-boiling of the ink. (R:LIBE]02745.doc:avc 1 ;A, -21

8. An ink jet recording head according to Claim 7, wherein said thermal energy generating members include electrothermal transducers.

9. An ink jet recording head according to Claim 1, wherein said top plate and said substrate are joined with a mechanical pressure before the sealant is applied. An ink jet recording head according to Claim 1, further comprising a base plate for mounting said substrate.

11. An ink jet recording apparatus comprising: an ink jet recording head according to any one of the preceding claims; and a mounting member for mounting said ink jet recording head.

12. An ink jet recording head substantially as described herein with reference to Figs. 1 to 4, or Figs. 5 to 7, or Figs. 9 to 11 or Figs. 12 and 13 of the drawings. S. S. *P 0 S. S 0 S 0 20 0 S q 0 S q S 0*' DATED this Twentieth Day of March, 2000 Canon Kabushiki Kaisha Patent Attorneys for the Applicant SPRUSON FERGUSON IR.\LIBE]02745.doc:avc