Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1998-08-24
2001-09-04
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S011000, C347S015000, C347S014000, C347S019000, C347S023000, C347S043000
Reexamination Certificate
active
06283568
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet printer for ejecting ink droplets through a droplet outlet orifice (a nozzle) and recording on paper and an apparatus and a method of driving a recording head for an ink-jet printer.
2. Description of the Related Art
Ink-jet printers for ejecting ink droplets through a droplet outlet orifice communicating with an ink chamber and recording on paper have been widely used. Ink droplet ejection has been controlled as follows in such ink-jet printers of related-art.
FIG. 1
is a schematic diagram of a recording head and a drive circuit thereof in a related-art ink-jet printer. As shown, a recording head
500
includes a nozzle
501
and a piezoelectric element
502
provided in correspondence with the nozzle
501
. The piezoelectric element
502
is fixed to a wall of an ink chamber (not shown) to which ink is supplied through an ink duct (not shown). A drive signal
504
of a specific waveform is selectively inputted to the piezoelectric element
502
through an on/ off switch
503
. That is, the drive signal
504
is only inputted to the piezoelectric element
502
when the switch
503
is turned on. On the application of the drive signal
504
, the piezoelectric element
502
is bent in such a direction that the ink chamber volume is reduced. An ink droplet is thereby ejected through the nozzle
501
.
For such printers, one of the methods for producing halftone images is varying a droplet size dot by dot. In the drive circuit of the recording head of related art shown in
FIG. 1
, however, only one type of drive signal is inputted to the piezoelectric element
502
so that whether to perform ejection or not is only controlled. Consequently, it is impossible to perform control for varying a size of ejected droplet from droplet to droplet although the interval between recorded dots is controlled. It is therefore difficult to faithfully achieve various image representations such as more natural halftone images.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an ink-jet printer and an apparatus and a method of driving a recording head for an ink-jet printer for faithfully performing various image representations through ink droplet ejection by means of drive signals of different waveforms.
An ink-jet printer of the invention comprises: a droplet outlet orifice through which an ink droplet is ejected; a means for generating energy for having the ink droplet ejected through the outlet orifice; a means for generating a plurality of drive signals; and a means for selecting any of the drive signals in a time-division manner and supplying the signal to the means for generating energy.
Another ink-jet printer of the invention comprises: a droplet outlet orifice through which an ink droplet is ejected; a means for generating energy for having the ink droplet ejected through the outlet orifice; a means for generating a plurality of drive signals including a drive signal having a varying voltage waveform that disables ink droplet ejection in isolation from another waveform; and a means for selecting any of the drive signals in a time-division manner and supplying the signal to the means for generating energy.
An apparatus of the invention is provided for driving a recording head for an ink-jet printer including a droplet outlet orifice through which an ink droplet is ejected and a means for generating energy for having the ink droplet ejected through the outlet orifice. The apparatus comprises: a means for generating a plurality of drive signals and a means for selecting any of the drive signals in a time-division manner and supplying the signal to the means for generating energy.
Another apparatus of the invention is provided for driving a recording head for an ink-jet printer including a droplet outlet orifice through which an ink droplet is ejected and a means for generating energy for having the ink droplet ejected through the outlet orifice. The apparatus comprises: a means for generating a plurality of drive signals including a drive signal having a varying voltage waveform that disables ink droplet ejection in isolation from another waveform and a means for selecting any of the drive signals in a time-division manner and supplying the signal to the means for generating energy.
A method of the invention is provided for driving a recording head for an ink-jet printer including a droplet outlet orifice through which an ink droplet is ejected and a means for generating energy for having the ink droplet ejected through the outlet orifice. The method comprises the steps of: generating a plurality of drive signals and selecting any of the drive signals in a time-division manner and supplying the signal to the means for generating energy.
Another method of the invention is provided for driving a recording head for an ink-jet printer including a droplet outlet orifice through which an ink droplet is ejected and a means for generating energy for having the ink droplet ejected through the outlet orifice. The method comprises the steps of: generating a plurality of drive signals including a drive signal having a varying voltage waveform that disables ink droplet ejection in isolation from another waveform and selecting any of the drive signals in a time-division manner and supplying the signal to the means for generating energy.
According to the ink-jet printer and the apparatus and the method of driving a recording head for an ink-jet printer, the selection of the drive signal may be switched to another at a point between a cycle in which the ink droplet is ejected and the next cycle. The selection of the drive signal may be switched to another at any point including a point during a cycle in which the ink droplet is ejected.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
REFERENCES:
patent: 4471363 (1984-09-01), Hanaoka
patent: 4897667 (1990-01-01), Uchiyama et al.
patent: 5130720 (1992-07-01), Lopez et al.
patent: 406 031 932 (1994-02-01), None
Horii Shinichi
Ikemoto Yuichiro
Kishimoto Masaki
Tanikawa Tooru
Tokunaga Hiroshi
Barlow John
Maioli Jay H.
Sony Corporation
Stewart Jr. Charles W.
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