Multi-Layer Ink Jet Apparatus

This invention relates to ink jet arrays including a plurality of ink jet channels where each channel includes a chamber, an inlet to the chamber, an orifice from the chamber and transducer means coupled to the chamber for ejecting droplets of ink from the chamber as a function of the state of energization of the transducer.

Layered or laminated ink jet structures are utilized to facilitate fabrication of ink jets which necessarily require a high degree of precision. Even higher degrees of precision are required in densely packed multi-channel impulse ink jet arrays.

However, there are certain limitations on high density packing of ink jet arrays. The most important limitation involves cross talk between channels. Of course, cross talk is undesirable and it is, therefore, necessary to provide a certain structural spacing between channels. This is sometimes achieved by using a fan-in technique such as that disclosed in U.S. Pat. No. 3,988,745--Sultan. As also shown herein, the ink jet chambers and transducers associated therewith are staggered with respect to one another. There are, however, limitations as to the amount of fanning in which may be done and this necessarily imposes limitations on the number of channels which may be utilized in such an array. Moreover, when attempts are made to add channels by adding layers to the device, the spacing or resolution of the channels within the device is increased, i.e., the clarity is reduced.

It is an object of this invention to achieve a multi-channel, high-density array of ink jets.

It is a more specific object of this invention to achieve a multi-channel, high-density array of ink jets which may be readily fabricated.

It is a further specific object of this invention to achieve a multi-channel, high-density ink jet array which is unlimited in the number of channels which may be employed.

In accordance with these and other objects of the invention, a preferred embodiment of the invention comprises an ink jet apparatus including a plurality of channels wherein each of the channels includes a chamber, an inlet opening to the chamber and an ink droplet ejection orifice. In accordance with this invention, the apparatus comprises a plurality of layers having at least one layer wherein different functions for more than one channel are performed.

In one embodiment of the invention, the chamber of one channel and the transducer of another channel are located in the same layer. In this embodiment, both a portion of the chamber and a restrictor for one channel may be formed in that same layer.

In the same or another embodiment of the invention, a deformable wall of one channel between the transducer and the chamber thereof and another nondeformable wall of another channel may be located in the same layer.

In accordance with another important aspect of the invention, a first plurality of the channels may be nonaligned with respect to a plane extending transverse to the layers.

In accordance with another important aspect of the invention, a second plurality of the channels including at least one channel from the first plurality may be aligned with respect to a plane extending transverse to the layers. The second plurality of channels may be supplied by a single supply channel extending transverse to the layers.

FIG. 1 is a perspective view of a laminated structure representing one preferred embodiment of the invention in an ink jet apparatus;

FIG. 2 is a sectional view of the apparatus of FIG. 1 displaying the various ink jet orifices;

FIG. 3 is a front elevational view of apparatus shown in FIG. 1;

FIGS. 4(a-j) are plan views of the various layers of the embodiment shown in FIGS. 1 and 2;

FIG. 5 is a perspective view of another embodiment of the invention;

FIG. 6 is a sectional view of the structure shown in FIG. 5;

FIG. 7 is a front elevational view of the embodiment shown in FIG. 5; and

FIGS. 8(a-n) are plan views of the various layers of the embodiment shown in FIGS. 5-7.

Referring to FIGS. 1-3, a laminated structure 10 includes a plurality of channels 12(a-f) including orifices 14 for ejecting droplets of ink.

In accordance with one important aspect of this invention, each of the orifices 14 is located in a different lamination or layer 16. This may be appreciated by reference to FIGS. 1 and 3 wherein the orifices 14 are shown as located at different depths within the structure 10. This achieves an array of orifices 14 which are slanted with respect to the planes of the layers 16.

In accordance with another important aspect of the invention, the same layer or lamination in the structure 10 serves different functions with respect to different channels. Referring to FIG. 2, the channel 12a is formed by a plurality of laminations including the lamination 16oa which forms the orifice of the the channel 12a, the lamination 16ra which serves as a restrictor and a portion of the chamber in the channel 12a, and the lamination 16da which serves as a diaphragm associated with a transducer 22 of the channel 12a. These laminations in combination with a cover lamination 16c form the channel 12a which includes a compression chamber 24 which is communicated with by the transducer 22 through the diaphragm lamination 16da.

In order to accommodate the transducer 22 and the associated electrical contact 26, it is necessary to provide openings in the adjacent laminations 16. However, these laminations 16 must, in accordance with this invention, serve functions for the other channels which lie at least in part at the same depth in the laminated structure. Accordingly, it is necessary to provide room for the transducer 22 and the contact 26 and laminations which also serve different functions in adjacent channels. Referring to FIG. 2, the necessary space or opening for the transducer 22 is, therefore, provided in a lamination 16ob which also serves as an orifice lamination for the channel 12b and a lamination 16rb which also serves as a restrictor in the channel 12b. A necessary space or opening for the contact 26 is provided in a lamination 16db which serves as the diaphragm for channel 12b and a lamination 16oc which forms an orifice for the channel 12c. These laminations complete the channel 12a except for the addition of some insulation 28 surrounding the transducer 22 and the contact 26 and a supply conduit 30 which is fed transversely through the various laminations 16. The conduit 30 is, of course, formed by aligned openings in the various laminations 16.

Referring still to FIG. 2, the channel 12d is located immediately above the channel 12a and comprises a series of laminations substantially identical to the laminations which form the channel 12a. Accordingly, the various laminations which form the channel 12d perform other functions for other channels. For example, the bottom of the chamber 24d of the channel 12d is formed by the lamination 16rc and the lamination 16dc which serve as a restrictor and a diaphragm respectively for the channel 12c. The chamber 24 as well as the orifice 14 for the channel 12d are formed by lamination 16od. The remainder of the channel 12d is formed by laminations 16rc, 16dc, 16rd, 16dd, 16oe, 16re, 16de, 16of, 16rf and 16df. As clearly suggested by the letters associated with the various laminations, these laminations also serve orifice, restrictor and diaphragm functions of adjacent channels in accordance with this invention.

The laminated structure 10 includes a reservior plate or lamination 16r at opposite extremities of the structure 10 as shown in FIGS. 1-3. The reservoir plates 16r include reservior chambers 32 which are coupled to the conduit 30 and suitable tubing 34 adapted to couple the structure 10 to a suitable source of ink. As shown in FIG. 1, the entire laminated structure 10 may be maintained as a unit by the use of screws 36. Holes 38 which are also shown in FIG. 1 provide convenient means for aligning the various laminations 16 during the assembly process.

Reference is now made to FIGS. 4(a-k) for a further discussion of the various laminations 16 and the portions of the various channels formed thereby.

FIG. 4a depicts the bottom cover 16c. As shown therein, the cover includes a plurality of holes 40 located at the four corners thereof for purposes of fastening the various laminations 16 together. Holes 38 are also shown which are utilized in aligning the various laminations 16. In addition, openings are shown which form the conduit 30. It will be appreciated that the cover 16c shown in FIG. 4a serves only a single function except for the conduit function provided by the openings 30, namely, the lower wall of the chamber 24 of the channel 12a.

FIG. 4b depicts the lamination of 16oa which includes an opening forming the chamber 24 as well as the orifice 14 for the channel 12a. In addition, the lamination 16oa includes openings 42 which are adapted to accommodate transducers 22 and contacts 26 for adjacent channels. However, since the lamination 16oa is used at the bottom of the laminated structure 10, the openings 42 are not required. However, their presence does permit the same lamination 16oa to be utilized in other positions in the laminated structure 10. More specifically, the lamination 16oa may be utilized to form the chamber 24 and the orifice 14 of the channel 12d. Accordingly, the lamination 16od shown in FIG. 2 may be identical with the lamination 16oa. This, of course, reduces the cost of fabrication since interchangeable parts may be utilized.

Referring now to FIG. 4c, the restrictor lamination 16ra is shown. The lamination 16ra includes an area 44 which is connected to the conduit 30 by means of a channel 46. Once again, an opening 42 is provided in the lamination 16ra so as to provide room for the transducer 22 and/or the contact 26 of an adjacent channel to provide the lamination interchangeability discussed in the foregoing. In other words, the lamination 16ra may be interchanged with the lamination 16rd shown in FIG. 2.

FIG. 4d illustrates the lamination 16da which forms the diaphragm between the chamber 24 and the transducer 22 in the channel 12a. As shown in FIG. 4d, the transducer 22 will contact the lamination 16da in the area enclosed within dotted lines. Since the lamination 16rd does provide for electrical connection with the transducer 22, a tab 48 is provided for facilitating electrical connection. In this regard, it will be understood that the lamination l6da may comprise a conductive material. FIG. 4d also shows the opening or area 42 which is adapted to receive the transducer 22 and/or contact 26 of an adjacent channel. Once again, it will be appreciated that the lamination 16da may be substituted or interchanged with a lamination for another channel, in particular, the lamination 16dd shown in FIG. 2.

The lamination 16ob as shown in FIG. 4e includes the chamber 24 and the orifice 14 for the channel 12b. Openings 42 are provided but only the opening 42 at the left of the chamber 24 is utilized to provide space for an actual transducer, i.e., the transducer 22 associated with the channel 12a. However, the lamination 16ob is interchangeable with the lamination 16oe used in forming the channel 12e and in that channel both of the openings 42 would be required to provide room for the transducers associated with channel 12d as well as channel 12c.

Referring to FIG. 4f, a chamber opening 24 and a passageway 46 back to the opening 30 is provided to serve as a restrictor for the chamber 24 and the channel 12b.

FIG. 4g represents the lamination 16db including an opening 42 to receive the transducer 22 and the contact 26 for the channel 12a. The transducer 22 for the channel 12b is adapted to rest on the lamination 16db in a position shown in dotted lines so as to provide a ground connection for the transducer 22 through a tab 48. It will be appreciated that the lamination 16rb and 16db as well as the lamination 16ob are interchangeable for lamination 16re, 16de and 16oe for the channel 12e as shown in FIG. 2.

FIG. 4h shows the lamination 16oc including the chamber 24 and the orifice 14 for the channel 12c. In addition to the conduit openings 30, openings 42 are provided to accommodate the transducers for the channels 12a and 12b respectively.

FIG. 4i represents the lamination 16rc which provides the restrictor for the channel 12c. For this purpose, the lamination 16rc comprises opening 44 and a passageway 46 connected back to the conduit opening 30. In addition, an opening 42 is provided to accommodate the transducer 22 and the contact 26 for the channel 12b.

FIG. 4j depicts the lamination 16dc which serves as the diaphragm for the chamber 12c on which the transducer 22 rests as shown by the dotted lines. An opening 42 is provided to accommodate the transducer 22 and the contact 26 for the channel 12b. A tab 48 again provides the ground connection for the transducer which is bonded to the lamination 16dc. It will be appreciated that the lamination 16oc, 16rc and 16dc may be interchanged for the laminations associated with the channel 12f in the laminated structure 10.

Finally, a top cover 16c is shown in FIG. 4k. The cover 16 as well as other laminations in FIGS. 4(b-j) includes the holes 38 and 40 as well as the conduit openings 30 which are also shown in the bottom cover in FIG. 4a. However, it will be understood that the top cover 16c is not placed on top of the lamination 16dc. Rather, it is placed on top of the entire six-channel array, just below the reservior plate 16r. It will be understood that additional laminations may be added before applying the top cover 16c so as to provide a virtually unlimited number of channels in a high density array.

With reference to FIGS. 4(a-k), it will be appreciated that the individual laminations 16 provide different functions for different channels. For example, FIG. 4b shows the lamination 16oa which, when used in place of the lamination 16od, forms the chamber 24 for the channel 12d as well as areas provided by the openings 42 for accommodating the transducers 22 for the channels 12e and f. This permits the chamber 24 for one channel and the transducer 22 for another channel to be located in the same layer or lamination, i.e., at the same depth in the laminated structure 10.

From FIG. 4c, it may be seen that the lamination 16ra when used in place of the lamination 16rd serves as a restrictor for the channel 12d of virtue of the opening 46 and an area 42 accommodates the transducer 22 for the channel 12f. In other words, the restrictor for one channel is located on the same layer as the transducer for another channel, i.e., both the restrictor and the transducer are located at the same depth in the laminated structure 10.

Referring to FIG. 4d, the lamination 16da when utilized as the lamination 16dd in FIG. 2 provides the deformable conductive wall for the transducer 22 and the channel 12d while also providing the nondeformable lowermost wall of the chamber 24 in the channel 12e.

Other dual functions are performed by the various laminations shown in FIG. 4. For example, the lamination 16ob provides the chamber 24 for the channel 12b while also providing openings 42 to accommodate transducers of other channels.

As stated previously, the orifices 14 are located in different laminations at different depths in the laminated structure 10. In the case of the laminated structure of FIG. 3, no two orifices 14 are located in the same layer and pluralities of orifices are aligned in planes perpendicular to the layer. However, this is not necessary where a particularly compact ink jet array is desired. As shown in the laminated structure 10 of FIGS. 1-4, certain pluralities (i.e. pairs) of orifices 14 are aligned in planes transverse to the various laminations 16. However, this may be modified so as to stagger (i.e., maintain nonaligned) a plurality of orifices 14 through the various layers of the laminated structure 10 as well as through planes perpendicular or transverse to the laminations 16 of the structure 10.

Referring to FIGS. 5 and 6, another ink jet apparatus is formed in a laminated structure 110. The laminated structure 110 includes a plurality of orifices 114. A total of eight orifices 114, for example, are provided with each orifice being located in a different layer or lamination with two sets of four orifices 114 which are aligned in planes substantially transverse or perpendicular to the laminations 116.

Referring to FIG. 6, the various laminations are shown which are associated with the channels 12a and 12g. Channel 12a is formed by the lamination 116c which forms a lowermost portion of an inlet passageway 150 which may include a restriction coupled to a chamber 124 formed in lamination 116oa. The top of the chamber 124 is formed by lamination 116ob in which the orifice 114 for the channel 112b is located and the lamination 116ob also provides communication between a transducer 122 and the chamber 124 where the transducer 122 is located in openings of the laminations 116oc and 116od. As shown in FIG. 7, the lamination s 116oc and 116od include the orifices for channels 112c and 112d.

The channel 112g is formed by laminations 116oe, 116of, 116og, 116oh and laminations 116s which serve as spacers to accommodate the transducer 122 of the channel 112g. As shown in FIG. 7, the laminations 116oe, 116of, 116og and 116oh form the orifices for the channels 112e, 112f, 112g and 112h respectively.

From the foregoing, it will be appreciated that adjacent laminations include orifices 114 and chambers 124. In order to accommodate this extremely dense array of orifices 114, it becomes necessary to avoid alignment of adjacent chambers 124 even though adjacent orifices 114 are aligned. In this connection, reference will now be made to FIG. 8.

The various laminations 116 are shown in FIG. 8. FIG. 8a illustrates the cover lamination 116c while FIG. 8b illustrates the restrictor lamination 116r including a passageway or opening 150. The passageway or opening 150 communicates with the chamber 124 in the lamination 116oa which fans into the orifices 114. The lamination 116oa also includes an inlet opening or passageway 150 which is adapted to serve the channel 112b.

The lamination 116ob includes the chamber 124 for the channel 12b and an electrical contact layer 152 which communicates with a transducer position shown in dotted lines. Another restrictor passageway 150 is also located in the lamination 116ob which supplies the channel 12c.

Although the various other laminations shown in FIG. 8 will not be discussed in detail, it will be appreciated by the reference characters utilized that similar functions herein described apply. It will be noted that there is no repetition in the chamber position 124 except for laminations which are substantially spaced from one another as depicted in FIG. 6. In this connection, it will be noted that the chambers 124 and both the lamination 116oa and the lamination 116og substantially correspond. The same is true with respect to the chambers 124 and the laminations 116ob and 116oh. Note also the uses of holes or openings 154 adapted to accommodate transducers as well as a conductive tab 156 which provides an electrical connection to the transducer.

As in the embodiment of FIGS. 1-4, the embodiment of FIGS. 5-8 also employs laminations where the single lamination serves different functions in different channels. Indeed, the various laminations 116 shown in FIG. 8 make it clear that a multiplicity of functions is served by a single lamination. For example, the laminations 116od, 116oe, 116of, 116og and 116oh provide five different functions for five different channels each.

It will be appreciated that various bonding techniques may be employed to fabricate the various structures disclosed herein. For example, it is desirable to employ an epoxy to form the bond between the laminations. Suitable epoxies such as #MA 115K Epoxy manufactured by McCann Manufacturing Company could be used. In the alternative, diffusion bonding between the laminations may be employed. In order to bond the transducer in place, a conductive epoxy may be used such as Ablebond #789-3 copper conductive epoxy.

Various lamination materials may be utilized although a photoetchable material is preferred. For example, AISI type 304 stainless steel is particularly well-suited.

Although particular embodiments of the invention have been shown and described, it will be appreciated that other modifications may be made which occurs to those of ordinary skill in the art and such modifications will fall within the true spirit and scope of the invention as set forth in the appended claims.