EP0639458B1 - Improved mounting arrangement for resonator - Google Patents
Improved mounting arrangement for resonator Download PDFInfo
- Publication number
- EP0639458B1 EP0639458B1 EP19940305467 EP94305467A EP0639458B1 EP 0639458 B1 EP0639458 B1 EP 0639458B1 EP 19940305467 EP19940305467 EP 19940305467 EP 94305467 A EP94305467 A EP 94305467A EP 0639458 B1 EP0639458 B1 EP 0639458B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- mounting
- resonator
- slots
- mounting arrangement
- tubes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/02—Ink jet characterised by the jet generation process generating a continuous ink jet
- B41J2/025—Ink jet characterised by the jet generation process generating a continuous ink jet by vibration
Definitions
- the present invention relates to continuous ink jet printing systems and, more particularly, to an improved means for constructing a resonant body to provide a synchronous break up of jets in an array in such printing systems.
- ink is supplied under pressure to a manifold region that distributes the ink to a plurality of orifices, typically arranged in a linear array(s).
- the ink discharges from the orifices in filaments which break into droplet streams.
- the approach for printing with these droplet streams is to selectively charge and deflect certain drops from their normal trajectories.
- U.S. Patent No. 4,999,647 discloses a system for achieving synchronous stimulation across a long array at a low frequency, approximately 50 KHz.
- the system of that patent uses a rectangular solid printhead body of high acoustic Q material, stainless steel, with vertical slots perpendicular to the array to provide a plurality of approximately identical resonant bodies.
- the slots are spaced equidistant from each other to provide for uniform vibrational amplitude across the major surface.
- the slots divide the drop generator into segments so that segment height, in the predominant vibration direction, is greater than the other dimensions of each segment.
- an ink manifold and orifice plate are located at one of the longitudinal ends parallel to the overall greatest length of the resonant body.
- the orifice plate provides for a continuous stream of jets to form drops at a frequency equivalent to the resonance of the body.
- the resonant body is excited by piezoelectric strip pairs mechanically attached to the sides so as to expand and contract in the desired direction.
- the resonator is mounted at the nodal plane by means of solid pins that are pressed into holes in the resonator body.
- the invention provides a mounting arrangement for a drop generator of an ink jet printing device, the generator having a resonator body and an orifice array having a common longitudinal axis with said body, the generator capable of producing continuous streams of ink drops from at least one said orifice, the mounting arrangement comprising, slots located in the resonant body perpendicular to the longitudinal axis of the array and body; and characterised by, a retaining portion, associated with a nodal plane of the resonator body, located in at least one of the slots; and at least one mounting member insertable into the retaining portion and said mounting member is at least partially hollow.
- Fig. 1 illustrates a droplet generator 10 which is used to create streams of ink, thus producing droplets used for printing in a continuous ink jet printer.
- Devices used for controlling these drops in a printer are aligned with the droplet generator 10 in a print head device to cooperate for printing purposes.
- the droplet generator 10 is typically constructed of a high acoustic Q material, such as stainless steel, in predetermined dimensions for length, height, and width.
- a through bore means 12 provides an inlet and an outlet for fluid flow into the drop generator 10.
- Piezoelectric strips 14 are affixed to the drop generator 10 with the longest length of the strips being perpendicular to the longitudinal axis of the drop generator, to encourage vibration, i.e., expansion and contraction, in the vertical direction.
- the droplet generator 10 is designed to provide a synchronous array of droplets for printers.
- the droplet generator includes a resonator/manifold body 16, the plurality of piezoelectric strips 14, an orifice plate (not shown), and a mounting arrangement means including mounting tubes 18.
- the mounting tubes 18 are used to mount the resonator 16 on a frame (not shown), to provide a means for mechanically aligning the resonator or drop generator to charge electrodes, and also to rigidly maintain that alignment. Consequently, the mounting arrangement of the present invention not only provides for isolating the drop generator from the frame to allow the drop generator to resonate properly, but also allows for a rigid mount to provide secure alignment.
- the mounting tubes 18, typically constructed of a steel material have a diameter of 1.65 to 1.98 mm (0.065 to 0.078 inches), and are hollow.
- the hollow tubes 18 typically have a wall thickness of 0.25 to 0.38 mm (0.010 inches to 0.015 inches). If the diameter of the mounting tubes is too small, there is less contact area between the tubes and the resonator, so the tubes are more likely to slide. Larger mounting tubes with a diameter of 2.29 mm (0.090 inches) or greater, were found to adversely affect stimulation uniformity. Consequently, the tubes preferably have a diameter of 1.98 mm (0.078 inches) to give sufficient contact area for reasonable resistance to sliding.
- the tubes are mounted in a tube receiving means, such as slots already existing in the resonator body, or additional apertures located along the resonator body added for the tube receiving purpose.
- the tubes 18 are insertable into vertical slots 20, located perpendicular to the longitudinal axis of the array and body.
- the width of each slot 20 is typically 1.57 mm (0.062 inches).
- One or more of the slots 20 may include a widened retaining portion 22, as illustrated at end slots 20a and 20b.
- the widened retaining portion 22 is located along or near the nodal plane of the resonator, for receiving the tubes 18.
- the diameter of the retaining portion 22 is typically 1.98 mm (0.078 inches) to provide for a tight press fit between the tubes 18 and the retaining portion 22 of the slots 20.
- the vertical slots 20, with retaining portions 22, provide a radius, then, for the mounting tubes 18.
- interior segments 24a, 24b, and 24c, located between each adjacent pair of slots 20, actually have a larger width dimension than a height dimension.
- End segments 26a and 26b, located between end slot 20a and one end of the resonator body 16 and end slot 20b and the other end of the resonator body 16, are narrower than the centrally situated interior segments 24a, 24b, and 24c, in order to improve vibrational uniformity across the array.
- the width of each slot 20 is typically 1.57 mm (0.062 inches).
- the tubes 18 should be tightly press fit into the retaining portion 22 of the slot 20.
- the tight fit of the tubing provides electrical contact between the droplet generator 10 and the tubes 18.
- the droplet generator 10 may therefore be grounded by means of a grounding point on the frame. Additional rigidity may be achieved by also using a bonding agent such as cyanoacrylate.
- hollow mounting tubes eliminates the undesirable high frequency resonances introduced by solid tubes. Additionally, mounting the tubes in the slots 20 results in only negligible changes in the resonant characteristics of the droplet generator 10, as opposed to the more noticeable and less desirable effects resulting from the use of separate holes for receiving mounting tubes 18. Of course, it will be obvious to those skilled in the art that the concept of the hollow tubes can reduce adverse effects, even when the hollow tubes are mounted in additional holes, rather than in the slots.
- the tubes 18 have been described as being hollow, it is occasionally desirable to secure the tubes into the frame by means of a clamp.
- the clamping force may distort the tube, which, unfortunately, relieves the clamping force.
- the end portion of the tube at the clamp point may be filled with a solid material, such as a dowel pin, to avoid the tube distortion while allowing for sufficient clamping force, without adverse effects.
- the present invention is useful in the field of ink jet printing, and has the advantage of improving the mounting of a resonator by eliminating adverse resonant characteristics.
Description
- The present invention relates to continuous ink jet printing systems and, more particularly, to an improved means for constructing a resonant body to provide a synchronous break up of jets in an array in such printing systems.
- In continuous ink jet printing, ink is supplied under pressure to a manifold region that distributes the ink to a plurality of orifices, typically arranged in a linear array(s). The ink discharges from the orifices in filaments which break into droplet streams. The approach for printing with these droplet streams is to selectively charge and deflect certain drops from their normal trajectories.
- In such continuous ink jet printing systems, graphic reproduction is accomplished by selectively charging and deflecting drops from the drop streams and depositing at least some of the drops on a print receiving medium while other of the drops strike a drop catcher device. In order to provide precise charging and deflecting of the drops, it is important that the drop break-up process produce uniformly sized and timed drops. Drop generators for such printers produce the required drop formation by vibrating the orifices from which the ink emerges.
- In the field of ink jet printers, it is desirable from the standpoint of throughput to utilize long arrays of ink jets. For example, U.S. Patent No. 4,999,647 discloses a system for achieving synchronous stimulation across a long array at a low frequency, approximately 50 KHz. The system of that patent uses a rectangular solid printhead body of high acoustic Q material, stainless steel, with vertical slots perpendicular to the array to provide a plurality of approximately identical resonant bodies. The slots are spaced equidistant from each other to provide for uniform vibrational amplitude across the major surface. The slots divide the drop generator into segments so that segment height, in the predominant vibration direction, is greater than the other dimensions of each segment.
- As described in the '647 patent, an ink manifold and orifice plate are located at one of the longitudinal ends parallel to the overall greatest length of the resonant body. The orifice plate provides for a continuous stream of jets to form drops at a frequency equivalent to the resonance of the body. The resonant body is excited by piezoelectric strip pairs mechanically attached to the sides so as to expand and contract in the desired direction. The resonator is mounted at the nodal plane by means of solid pins that are pressed into holes in the resonator body.
- It has been found that this mounting system works well for a drop generator having a 114.3 mm (4½ inch) array with a resonant frequency near 50 KHz. However, for higher frequencies, on the order of 100 KHz, it is seen that the solid pins induce undesirable resonant modes. These resonant modes can produce unacceptably large variations in break-off phase across the array. Additionally, the holes in which the pins are mounted can further adversely affect the resonance.
- It is seen then that there is a need for an improved mounting arrangement for the resonator, which overcomes the problems associated with the prior art.
- This need is met by the resonator mounting arrangement of the present invention, wherein hollow tubes are mounted in slots, eliminating the adverse resonant effects of solid pins and pin retaining holes.
- The invention provides a mounting arrangement for a drop generator of an ink jet printing device, the generator having a resonator body and an orifice array having a common longitudinal axis with said body, the generator capable of producing continuous streams of ink drops from at least one said orifice, the mounting arrangement comprising, slots located in the resonant body perpendicular to the longitudinal axis of the array and body; and characterised by, a retaining portion, associated with a nodal plane of the resonator body, located in at least one of the slots; and
at least one mounting member insertable into the retaining portion and said mounting member is at least partially hollow. - Other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.
- The invention will now be described by way of example only with reference to the accompanying drawing, in which:
- Fig. 1 is a perspective view of a droplet generator assembly illustrating the mounting arrangement of the present invention.
- Referring to the drawing, Fig. 1 illustrates a
droplet generator 10 which is used to create streams of ink, thus producing droplets used for printing in a continuous ink jet printer. Devices used for controlling these drops in a printer (not shown) are aligned with thedroplet generator 10 in a print head device to cooperate for printing purposes. - The
droplet generator 10 is typically constructed of a high acoustic Q material, such as stainless steel, in predetermined dimensions for length, height, and width. A through bore means 12 provides an inlet and an outlet for fluid flow into thedrop generator 10.Piezoelectric strips 14 are affixed to thedrop generator 10 with the longest length of the strips being perpendicular to the longitudinal axis of the drop generator, to encourage vibration, i.e., expansion and contraction, in the vertical direction. - The
droplet generator 10 is designed to provide a synchronous array of droplets for printers. The droplet generator includes a resonator/manifold body 16, the plurality ofpiezoelectric strips 14, an orifice plate (not shown), and a mounting arrangement means includingmounting tubes 18. Themounting tubes 18 are used to mount theresonator 16 on a frame (not shown), to provide a means for mechanically aligning the resonator or drop generator to charge electrodes, and also to rigidly maintain that alignment.
Consequently, the mounting arrangement of the present invention not only provides for isolating the drop generator from the frame to allow the drop generator to resonate properly, but also allows for a rigid mount to provide secure alignment. - In accordance with the present invention, the
mounting tubes 18, typically constructed of a steel material, have a diameter of 1.65 to 1.98 mm (0.065 to 0.078 inches), and are hollow. Thehollow tubes 18 typically have a wall thickness of 0.25 to 0.38 mm (0.010 inches to 0.015 inches). If the diameter of the mounting tubes is too small, there is less contact area between the tubes and the resonator, so the tubes are more likely to slide. Larger mounting tubes with a diameter of 2.29 mm (0.090 inches) or greater, were found to adversely affect stimulation uniformity. Consequently, the tubes preferably have a diameter of 1.98 mm (0.078 inches) to give sufficient contact area for reasonable resistance to sliding. - The tubes are mounted in a tube receiving means, such as slots already existing in the resonator body, or additional apertures located along the resonator body added for the tube receiving purpose. In a preferred embodiment, the
tubes 18 are insertable intovertical slots 20, located perpendicular to the longitudinal axis of the array and body. The width of eachslot 20 is typically 1.57 mm (0.062 inches). One or more of theslots 20 may include a widenedretaining portion 22, as illustrated atend slots portion 22 is located along or near the nodal plane of the resonator, for receiving thetubes 18. The diameter of theretaining portion 22 is typically 1.98 mm (0.078 inches) to provide for a tight press fit between thetubes 18 and theretaining portion 22 of theslots 20. Thevertical slots 20, withretaining portions 22, provide a radius, then, for themounting tubes 18. - In the present invention,
interior segments 24a, 24b, and 24c, located between each adjacent pair ofslots 20, actually have a larger width dimension than a height dimension.End segments 26a and 26b, located betweenend slot 20a and one end of theresonator body 16 andend slot 20b and the other end of theresonator body 16, are narrower than the centrally situatedinterior segments 24a, 24b, and 24c, in order to improve vibrational uniformity across the array. The width of eachslot 20 is typically 1.57 mm (0.062 inches). With the narrower slots of the present invention, as compared to slots of the prior art, vibrational uniformity and separation from undesirable resonant modes is improved by increasing the width of the interior segments beyond that of their height. This clearly counters the teachings of the prior art, which required that the width of each segment be less than the height of each segment. - The
tubes 18 should be tightly press fit into theretaining portion 22 of theslot 20. The tight fit of the tubing provides electrical contact between thedroplet generator 10 and thetubes 18. Thedroplet generator 10 may therefore be grounded by means of a grounding point on the frame. Additional rigidity may be achieved by also using a bonding agent such as cyanoacrylate. - Providing hollow mounting tubes eliminates the undesirable high frequency resonances introduced by solid tubes. Additionally, mounting the tubes in the
slots 20 results in only negligible changes in the resonant characteristics of thedroplet generator 10, as opposed to the more noticeable and less desirable effects resulting from the use of separate holes for receivingmounting tubes 18. Of course, it will be obvious to those skilled in the art that the concept of the hollow tubes can reduce adverse effects, even when the hollow tubes are mounted in additional holes, rather than in the slots. - Although the
tubes 18 have been described as being hollow, it is occasionally desirable to secure the tubes into the frame by means of a clamp. With the hollow tubes of the present invention, the clamping force may distort the tube, which, unfortunately, relieves the clamping force. To prevent this, the end portion of the tube at the clamp point may be filled with a solid material, such as a dowel pin, to avoid the tube distortion while allowing for sufficient clamping force, without adverse effects. - The present invention is useful in the field of ink jet printing, and has the advantage of improving the mounting of a resonator by eliminating adverse resonant characteristics.
- The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that modifications and variations can be effected within the scope of the appended claims.
Claims (3)
- A mounting arrangement for a drop generator (10) of an ink jet printing device, the generator having a resonator body (16) and an orifice array having a common longitudinal axis with said body, the generator capable of producing continuous streams of ink drops from at least one said orifice, the mounting arrangement comprising:slots (20) located in the resonant body perpendicular to the longitudinal axis of the array and body; and characterised by,a retaining portion (22), associated with a nodal plane of the resonator body, located in at least one of the slots (20); andat least one mounting member (18) insertable into the retaining portion and said mounting member is at least partially hollow.
- A mounting arrangement as claimed in claim 1, wherein the at least one mounting member (18) comprises a mounting tube, and a solid material is provided in an end portion of the at least one mounting tube at a clamp point to prevent distortion of the tube during clamping.
- A mounting arrangement as claimed in any one preceding claim, wherein the resonator body (16) has at least one interior segment (24a, b, c) defined by adjacent pairs of slots (20), and end segments (26a, b) between each end slot (20a, b) and each end of the resonator body, each interior segment having a greater width, measured parallel to the longitudinal axis of the resonator body, dimension than a height dimension, and each end segment being narrower in width than each interior segment.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10793593A | 1993-08-17 | 1993-08-17 | |
US107935 | 1993-08-17 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0639458A2 EP0639458A2 (en) | 1995-02-22 |
EP0639458A3 EP0639458A3 (en) | 1995-07-12 |
EP0639458B1 true EP0639458B1 (en) | 1997-11-12 |
Family
ID=22319273
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19940305467 Expired - Lifetime EP0639458B1 (en) | 1993-08-17 | 1994-07-25 | Improved mounting arrangement for resonator |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0639458B1 (en) |
DE (1) | DE69406734T2 (en) |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4188635A (en) * | 1977-10-03 | 1980-02-12 | International Business Machines Corporation | Ink jet printing head |
DE3364155D1 (en) * | 1982-06-21 | 1986-07-24 | Eastman Kodak Co | A fluid jet print head, and a method of stimulating the break up of a fluid stream emanating therefrom |
CA1215577A (en) * | 1982-12-27 | 1986-12-23 | Hilarion Braun | Fluid jet print head and stimulator therefor |
US4999647A (en) * | 1989-12-28 | 1991-03-12 | Eastman Kodak Company | Synchronous stimulation for long array continuous ink jet printer |
-
1994
- 1994-07-25 DE DE1994606734 patent/DE69406734T2/en not_active Expired - Lifetime
- 1994-07-25 EP EP19940305467 patent/EP0639458B1/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
EP0639458A3 (en) | 1995-07-12 |
DE69406734D1 (en) | 1997-12-18 |
EP0639458A2 (en) | 1995-02-22 |
DE69406734T2 (en) | 1998-03-12 |
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