Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-04-30
2003-06-03
Vo, Anh T. N. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06572210
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a liquid jetting apparatus having a head capable of jetting a drop of liquid from a nozzle. In particular, this invention is related to a liquid jetting apparatus having a head of jetting a plurality of drops of liquid from a nozzle wherein respective volumes of the plurality of drops of liquid may be different.
BACKGROUND OF THE INVENTION
In a ink-jetting recording apparatus such as an ink-jetting printer or an ink-jetting plotter (a kind of liquid jetting apparatus), a recording head (head) can move in a main scanning direction, and a recording paper (a kind of recording medium) can move in a sub-scanning direction perpendicular to the main scanning direction. While the recording head moves in the main scanning direction, a drop of ink can be jetted from a nozzle of the recording head onto the recording paper. Thus, an image including a character or the like can be recorded on the recording paper. For example, the drop of ink can be jetted by causing a pressure chamber communicating with the nozzle to expand and/or contract.
The pressure chamber may be caused to expand and/or contract, for example by utilizing deformation of a piezoelectric vibrating member. In such a recording head, the piezoelectric vibrating member can be deformed based on a supplied driving-pulse in order to change a volume of the pressure chamber. When the volume of the pressure chamber is changed, a pressure of the ink in the pressure chamber may be changed. Then, the drop of ink is jetted from the nozzle.
In such a recording apparatus, a driving signal consisting of a series of a plurality of driving-pulses is generated. On the other hand, printing data including level data (gradation data) can be transmitted to the recording head. Then, based on the transmitted printing data, only necessary one or more driving-pulses are selected from the driving signal and supplied to the piezoelectric vibrating member. Thus, a volume of the ink jetted from the nozzle may be changed based on the level data.
In detail, for example, a ink-jetting printer may be used with four level data including: a level data 00 for no dot, a level data 01 for a small dot, a level data 10 for a middle dot and a level data 11 for a large dot. In the case, respective volumes of the ink corresponding to the respective level data may be jetted.
However, recently, it is requested to satisfy user's various demands with only one ink-jetting recording apparatus. That is, it is requested that one ink-jetting recording apparatus can achieve a plurality of detailed demands, for example recording with high quality, recording at a high speed with not low quality or the like.
Some conventional ink-jetting recording apparatuses can achieve to improve quality of printed images by changing volumes of jetted ink based on a plurality of level data. However, in the conventional ink-jetting recording apparatuses, the number of the plurality of level data is too small to satisfy various detailed demands.
The number of bits of level data may be uniformly increased in order to set the volumes of jetted ink in detail. However, when printing data include the increased number of bits of level data, it needs a longer time to transmit the printing data to the recording head, which results in a low recording speed.
A clock for transmitting the printing data may be one for a higher speed in order to shorten the time for transmitting the data. However, the clock for the higher speed needs to use devices operable with a higher frequency, which results in larger consumed power and/or a more cost.
SUMMARY OF THE INVENTION
The object of this invention is to solve the above problems, that is, to provide a liquid jetting apparatus such as an ink-jet recording apparatus that can satisfy user's various demands by effectively using a plurality of level data, even when the number of the plurality of level data is small.
In order to achieve the object, a liquid jetting apparatus includes: a head having a nozzle; a pressure-changing unit for causing pressure of liquid in the nozzle to change in such a manner that the liquid is jetted from the nozzle; a jetting-mode setting unit for setting a selected jetting mode from a plurality of jetting modes; a level-data setting unit for setting a selected level data from a plurality of level data, based on a jetting data; a driving-signal generator for generating a driving signal, based on the selected jetting mode; a driving-pulse generator for generating a driving pulse based on the selected level data and the driving signal; and a main controller for causing the pressure-changing unit to operate, based on the driving pulse; wherein driving pulses generated based on a selected jetting mode and respective selected level data are different from driving pulses generated based on another selected jetting mode and the respective selected level data.
According to the feature, the driving signal is generated based on the selected jetting mode, and the driving pulse is generated based on the driving signal and the selected level data based on the jetting data. Thus, a manner of jetting the liquid by the driving pulse may be controlled by two factors of the jetting mode and the level data, which may enable to satisfy the user's various demands.
Preferably, volumes of the liquid jetted from the nozzle based on respective driving pulses are different according to respective jetting modes with respect to a same level data and different according to respective level data with respect to a same jetting mode.
According to the feature, since the volumes of the liquid jetted from the nozzle are different, a jetting speed and/or jetting quality may be controlled more effectively.
In detail, for example, the driving signal may be a periodical signal including a plurality of pulse-waves; and the driving pulse generator is adapted to generate a rectangular-pulse row corresponding to a period of the driving signal based on the selected level data, and generate an AND signal of the rectangular-pulse row and the driving signal as the driving pulse. In the case, quick signal processing can be achieved.
Preferably, the plurality of jetting modes may include a first jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the first jetting mode is a periodical signal including n separated small-drop pulse-waves, each of which is for jetting a small drop of the liquid from the nozzle, n being not less than three, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the first jetting mode:
a driving-pulse including only p small-drop pulse-waves when the selected level data is the small-dot data, p being one or more,
a driving-pulse including only q small-drop pulse-waves when the selected level data is the middle-dot data, q being more than p, and
a driving-pulse including r small-drop pulse-waves when the selected level data is the large-dot data, r being more than q and not more than n.
Alternatively, the plurality of jetting modes may include a first jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the first jetting mode is a periodical signal including three separated small-dot pulse-waves, each of which is for jetting a small-dot drop of the liquid from the nozzle, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the first jetting mode:
a driving-pulse including only one small-dot pulse-wave when the selected level data is the small-dot data,
a driving-pulse including only two small-dot pulse-waves when the selected level data is the middle-dot data, and
a driving-pulse including all the three small-dot pulse-waves when the selected level data is the large-dot data.
These first jetting modes are suitable for jetting at a high speed.
Preferably, the plurality of jetting modes may include a second jetting mode,
Dudding Alfred E
Vo Anh T. N.
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