Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-01-25
2004-04-27
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06726299
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus, and more particularly, to an ink jet recording apparatus capable of switching between different levels of resolution in a main scanning direction and having a simple configuration.
In a related ink jet recording apparatus, a recording head is moved in the main scanning direction (e.g., the widthwise direction of paper), and ink droplets are jetted from the recording head in synchronism with movement of the recording head. A recording apparatus of this type forms a basic unit pixel by a plurality of ink droplets (e.g. three or four) arranged in the main scanning direction. In this recording apparatus, a drive signal is cyclically and repeatedly generated on a per-print-cycle-basis, wherein a plurality of drive pulses, each pulse having the same waveform pattern, are spaced at constant intervals (meaning that an ink droplet jetted from the actuator as a result of a single waveform being applied to the actuator assumes a substantially constant volume). The drive pulses are arranged in a train and spaced at constant intervals. When a basic unit pixel image is recorded on a recording medium, the drive pulses are selectively supplied to pressure generating elements of the recording head, whereby ink droplets are jetted from the recording head. The recording head employed in the recording apparatus has a row of nozzles formed by arranging a plurality of nozzle orifices in a subscanning direction (e.g., a direction in which paper is to be fed).
In such a recording apparatus, when an attempt is made to perform a recording operation through use of fewer ink droplets required to form an unit pixel, there can be performed a high-resolution recording operation, in which the resolution of an image or character is enhanced with reference to the main scanning direction. In other words, there can be effected switching between a basic mode for effecting recording operation through use of basic unit pixels and a high-resolution mode for effecting recording operation through use of fine unit pixels that are of higher resolution than the basic unit pixels. For instance, in a case where a basic unit pixel to be used in a basic mode consists of four ink droplets, a forward fine unit pixel is formed by combination of the first and second ink droplets, and a rear fine unit pixel is formed by combination of the third and fourth ink droplets. Accordingly, recording can be effected in a high-resolution mode with the level of resolution with respect to the main scanning direction being enhanced to twice that in the basic mode.
However, a recent recording apparatus tends to shorten a single print cycle, in order to improve type speed. Moreover, the number of nozzle orifices constituting the row of nozzles; that is, the number of jetting data sets to be recorded by a single row of nozzles, tends to increase. On one hand, the number of jetting data sets to be recorded within a print cycle increases. On the other hand, setting of the jetting data sets must be performed within a shorter time period. If one dot is recorded in the high-resolution mode; that is, if recording is effected by means of sending data for each fine unit pixel, jetting data must be set within a considerably short time period, thus rendering control of recording operation difficult. Consequently, there must be taken measures to prolong a print cycle within a high-resolution mode or to decrease scanning speed of a carriage, or like measures, thus decreasing the print speed.
SUMMARY OF THE INVENTION
The present invention has been conceived under the circumstances set forth and is aimed at providing an ink jet recording apparatus enabling recording without involvement of a decrease in print speed even in the high-resolution mode.
In order to achieve the above object, according to the present invention, there is provided An ink jet recording apparatus comprising:
a recording head provided with a pressure generating element;
a scanning mechanism for moving the recording head in a main scanning direction;
a data developer for developing print data into jetting data;
a drive signal generator for generating a drive signal including a plurality of drive pulses, on every unit print cycle;
a translator for translating the jetting data into pulse select information associated with the respective drive pulses;
a drive pulse supplier for selectively supplying at least one of the drive pulses to the pressure generating element in accordance with the pulse select information to drive the pressure generating element;
a basic recording mode for recording through use of a basic unit pixel which is associated with a unit recording area corresponding to the unit print cycle;
a high-resolution recording mode for recording through use of a fine unit pixel, a plurality of fine unit pixels being arranged within the unit recording area in the main scanning direction; and
a mode selector for selecting one of plural recording modes including the basic recording mode and the high-resolution recording mode,
wherein the data developer develops the print data into the jetting data such that each bit therein indicates whether the recording is conducted or not in each associated fine unit pixel, when the mode selector selects the high-resolution recording mode.
Here, the expression “print data” means data transmitted from a host computer or a like device to the recording apparatus, and the expression “jetting data” means data to be transmitted to the recording head.
Preferably, the data developer develops the print data into the jetting data such that bits therein indicate gradation recorded in the unit recording area, when the mode selector selects the basic recording mode.
Preferably, the translator is provided with waveform select tables associated with the respective recording modes. Each of the waveform select table defines a correspondence between the jetting data and the pulse select information in the associated recording mode. The translator translates the jetting data into the pulse select information with reference to the waveform select table of the recording mode selected by the mode selector. More preferably, the waveform select table is rewritable. In this configuration, rewriting of data suitable for a recording mode can implemented more flexibly.
Preferably, the mode selector selects the recording mode in accordance with the print data. In this configuration, a recording mode suitable for the print data can be set up.
Preferably, the plural drive pulses are of an identical profile. More preferably, the plural drive pulses are spaced at constant intervals within the unit print cycle.
Preferably, an initial trigger for starting the unit print cycle is derived from the scanning mechanism.
Preferably, the jetting data of plurality of bits are parallel-transmitted from the data developer to the recording head.
According to the present invention, there is also provided an ink jet recording apparatus comprising:
a recording head provided with a pressure generating element;
a scanning mechanism for moving the recording head in a main scanning direction;
a drive signal generator for generating a drive signal including a plurality of drive pulses, on every unit print cycle;
a drive pulse supplier for selectively supplying at least one of the drive pulses to the pressure generating element in accordance with print data, to drive the pressure generating element; and
a high-resolution recording mode for recording through use of a fine unit pixel, a plurality of fine unit pixels being arranged in the main scanning direction within a unit recording area corresponding to the unit print cycle,
wherein the drive pulse supplier divides the drive pulses in the drive signal into a plurality of groups each including a same number of the drive pulses such that the last drive pulse included in a group used for a fine unit pixel to be recorded previously is also included in a group used for a fine unit pixel to be recorded subsequently, and supplies the drive pulses included in at least
Takahashi Tomoaki
Tamura Noboru
Huffman Julian D.
Meier Stephen D.
Seiko Epson Corporation
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