Method and apparatus for controlling the formation and shape of droplets in an ink jet stream
AssigneeInternational Business Machines Corporation
InventorHoward Hyman Taub
Life of this patent
Estimating the term…
Abstract
Method and apparatus is described for controlling the formation and shape droplets in an ink jet stream. The continuous portion of the stream is illuminated with a radiant energy source such as a laser. The surface wave profile produced by illuminating the stream is sensed to provide the fundamental and harmonic frequency components thereof. A perturbation drive signal, the amplitude and relative phase of which is a function of the sensed frequency components, is provided for controlling the formation and shape of the droplets.
Claims10
In an ink jet printing system, a method of controlling the formation of droplets in an ink jet stream, said method comprising the steps of:
- illuminating said ink jet stream in a region where the stream has yet to break up to form droplets;
- sensing the surface wave profile of the illuminated ink jet stream;
- responding to the sensed surface wave profile for providing a first signal at a frequency F;
- responding to the sensed surface wave profile for providing at least a second signal at a freuqency nF, where n is an integer .gtoreq.2;
- and
- combining said first and second signals to provide a control signal which is used to excite said ink jet stream, which excitation controls the formation of droplets.
In an ink jet printing system, a method of controlling the formation of droplets in an ink jet stream, said method comprising the steps of:
- illuminating the continuous portion of said ink jet stream with a source of radiant energy;
- sensing the surface wave profile of the illuminated ink jet stream;
- responding to the sensed surface wave profile for providing a first signal at the fundamental frequency F of the ink jet stream;
- responding to the sensed surface wave profile for providing at least a second signal at a frequency nF, where n is an integer .gtoreq.2;
- and summing said first and second signals to provide a control signal which is used to excite said ink jet stream for controlling the formation of droplets.
In an ink jet printing system, apparatus for controlling the shape of droplets at break-off in an ink jet stream, said apparatus comprising:
- means for illuminating said ink jet stream in a region where the stream has yet to break up to form droplets;
- means for sensing the surface wave profile of the illuminated ink jet stream;
- means responsive to the sensed surface wave profile for providing a first signal at a frequency F, the amplitude of which is a function of the sensed surface wave profile;
- means responsive to the sensed surface wave profile for providing at least a second signal at a frequency nF, where n is an integer .gtoreq.2, with the amplitude and phase of said second signal being a function of the sensed surface wave profile;
- and
- means for combining said first and second signals to provide a control signal which is used to excite said ink jet stream, for controlling the shape of droplets at break-off from said ink jet stream.
In an ink jet printing system apparatus for controlling the shape of the droplets at break-off in an ink jet stream, said apparatus comprising:
- means for illuminating the continuous portion of said ink jet stream with a source of radiant energy;
- means for sensing the surface wave profile of the illuminated ink jet stream;
- means responsive to the sensed surface wave profile for providing a first signal at the fundamental frequency F of the ink jet stream, the amplitude of which is a function of the sensed surface wave profile;
- means responsive to the sensed surface wave profile for providing at least a second signal at a frequency nF, where n is an integer .gtoreq.2, with the amplitude and phase of said second signal being a function of the sensed surface wave profile;
- and
- means for summing said first and second signals to provide a control signal which is used to excite said ink jet stream for controlling the shape of droplets at break-off from said ink jet stream.
In an ink jet printing system, apparatus for controlling the shape of droplets at the point of break-off in an ink jet stream, said apparatus comprising:
- a source of ink which emits an ink jet stream;
- perturbation means for perturbing said source of ink for causing the formation droplets;
- means for illuminating the continuous portion of said ink jet stream with a source of radiant energy;
- means for sensing the surface wave profile of the illuminated ink jet stream, and for converting same to an electrical signal containing the frequency components of the sensed radiant energy;
- a first means responsive to said electrical signal for providing a first signal at the fundamental frequency F of the ink jet stream, the amplitude of which is a function of the sensed fundamental frequency component of the sensed surface wave profile;
- a second means responsive to said electrical signal for providing at least a second signal at a frequency nF, where n is .gtoreq.2, with the amplitude and phase of said second signal being a function of the sensed fundamental and nth frequency of the sensed surface wave profile;
- and
- means for summing said first and second signals to provide a control signal which is applied to said perturbation means for controlling the perturbation of said ink jet stream and the shape of droplets at the point of break-off from said ink jet stream.
Dependencies are inferred from the claim text.