Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-10-17
2004-03-30
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S009000, C347S010000, C347S011000, C347S015000
Reexamination Certificate
active
06712445
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a liquid jetting apparatus having a head member capable of jetting drops of liquid from nozzles. In particular, this invention relates to a liquid jetting apparatus that can suitably control a full-jetting state, which is called “fully-covering”.
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 member) 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.
The above recording apparatus can be used for jetting a plurality of kinds of ink. In the case, it is preferable that a driving signal is generated for each of the plurality of kinds of ink. However, in order to avoid problems such as cost in forming a circuit for generating the respective driving signals, a common driving signal may be used for all the plurality of kinds of ink.
In the latter case, it is usual that a controlling state for “fully-covering (fully-painting)” wherein level data of the highest density are continuous is adjusted for a kind of ink difficult to achieve the “fully-covering”, that is, a kind of ink having a low ink-expansion characteristic (for example, a black ink).
However, if the “fully-covering” control is adjusted for the kind of ink having a low ink-expansion characteristic, regarding a kind of ink having a high ink-expansion characteristic (for example, a color ink), an amount of ink more than necessary to achieve the “fully-covering” is jetted, which tends to generate some oozy ink, which may cause a deterioration of recording quality.
In order to avoid the above problem, the inventor studied to adopt a “DUTY limit”. However, if the “DUTY limit” is adopted, the resolution and the level steps are also reduced, that is, it becomes difficult to maintain the high recording quality.
In addition, in the above recording head, in order to improve the recording speed or the like, a plurality of nozzles may be formed in the recording head. In the case, the characteristic of jetting an ink drop in each nozzle may be different from each other, because of a reason regarding manufacture of the recording head or the like.
In conventional recording heads, there is no attempt to precisely adjust the volume (weight) of an ink drop jetted from each nozzle for one pixel according to the same level datum. However, if the volume (weight) of an ink drop jetted from a nozzle for one pixel according to the same level datum is different from that from another nozzle, a problem about the recording quality may be generated in particular in a full-jetting (fully-covering) control.
The inventor studied to generate a driving signal for each nozzle in order to jet a proper volume (weight) of ink drop always. However, in the view of cost in forming a circuit for generating the driving signals or the like, the inventor judged that the concept is not practical at least for the present.
SUMMARY OF THE INVENTION
The object of this invention is to provide a liquid jetting apparatus such as a ink-jet recording apparatus that can suitably control a full-jetting state called “fully-covering”, even if a common driving signal is used for respective kinds of liquid.
In order to achieve the object, the invention is a liquid jetting apparatus comprising: a head member having a nozzle; a pressure-changing unit that can cause 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 that can set a selected jetting mode from a plurality of jetting modes; a driving-signal generator that can generate a common jetting-driving signal; a driving-pulse generator that can generate a full-jetting driving pulse, based on the selected jetting mode and the common jetting-driving signal; and a full-jetting main controller that can cause the pressure-changing unit to operate, based on the full-jetting driving pulse.
According to the above feature, since the full-jetting driving pulse is generated based on the selected jetting mode and the common jetting-driving signal, even if the common jetting-driving signal is used for a plurality of kinds of liquid, the full-jetting state can be controlled suitably for each of the plurality of kinds of liquid.
Preferably, weights of the liquid jetted from the nozzle based on respective full-jetting driving pulses are different according to respective jetting modes. That is, by making actual weights of the jetted liquid different, a uniform “fully-covering” can be easily achieved even although the respective kinds of liquid have respective liquid-expansion characteristics.
Preferably, the common jetting-driving signal is a periodical signal including a plurality of (separated) the same pulse-waves within a period thereof, and the driving-pulse generator is adapted to generate a rectangular-pulse row corresponding to the period of the common jetting-driving signal based on the selected jetting mode, and generate an AND signal of the rectangular-pulse row and the common jetting-driving signal as the full-jetting driving pulse.
If the above manner is adopted, a process of generating the full-jetting driving pulse can be easily materialized.
In a concrete example, if the plurality of jetting modes include a first jetting mode and a second jetting mode, and the common jetting-driving signal is a periodical signal including n the same pulse-waves within a period thereof, the driving-pulse generator can generate a full-jetting driving-pulse including only p pulse-waves when the selected jetting mode is the first jetting mode, p being one or more, and another full-jetting driving-pulse including only q pulse-waves when the selected jetting mode is the second jetting mode, q being more than p and not more than n, based on the common jetting-driving signal.
In the case, for example, a weight of the liquid jetted from the nozzle based on the one pulse-wave is 7 ng.
In addition, for example, n=7, p=5 or 6, and q=7.
In addition, preferably, the jetting-mode setting unit has: an input part into which desired dense-thin information is inputted by a user, and a jetting-mode setting main part that is adapted to set a selected jetting mode based on the desired dense-thin information inputted into the input part. In the case, a “fully-covering” control based on dense-thin desire of the user can be achieved.
In detail, for example, the jetting-mode setting main part can change at least one of p and q, based on the desired dense-thin information inputted into the input part.
In addition, it is preferable that the jetting-mode setting unit sets
Dudding Alfred E
Meier Stephen D.
Seiko Epson Corporation
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