Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-04-17
2004-07-06
Pham, Hai (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S010000, C347S011000
Reexamination Certificate
active
06758544
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to an ink jet printer capable of jetting ink droplets having different sizes from the same nozzle. More specifically, the present invention is directed to such an ink jet printer capable of jetting a plurality of ink droplets during a single printing time period.
As output apparatus of computers, color ink jet printers have been popularized in which several colors of ink are jetted from printing heads. To print out images processed by computers and the like in multi-color multi-gradation modes, these color ink jet printers have been widely employed.
An ink jet printer contains a printing head equipped with a large number of nozzles arranged in a sub-scanning direction (namely, paper feeding direction). While this printing head is moved by a carriage mechanism along a main scanning direction, a predetermined paper feeding operation is carried out along the above-described sub-scanning direction, so that a desirable print result is obtained. Based upon dot pattern data generated by converting printing data supplied from a host computer, ink droplets are jetted from the respective nozzles of the printing head at preselected timing. Then, the respective ink droplets are impacted onto a recording medium such as recording paper, and are adhered thereon, so that a printing operation is carried out. As previously described, since the ink jet printer determines as to whether or not the ink droplets are jetted, namely executes ON/OFF controls of dots, this ink jet printer cannot directly print out half-tone gradation such as a gray color.
Under such a circumstance, there have been utilized ink jet printers capable of controlling variably diameters of recording dots in such a manner that a plurality of ink droplets having different ink weights are jetted from the same nozzle. For instance, in such an ink jet printer described in Japanese Patent Publication No. 10-81013A, while a drive signal which is outputted every one printing time period is constituted by a plurality of drive pulses, at least one of drive pulses is selected based upon such printing data containing pulse selection signals corresponding to the respective drive pulses. In other words, in the related ink jet printer described in the publication, for example, the drive signal outputted every one printing time period is constituted by four drive pulses made of a first pulse (middle dot), a second pulse (small dot), a third pulse (middle dot), and a fourth pulse (meniscus vibration). While 1-bit data is allocated with respect to each of these drive pulses, jetting data is constructed. Then, in the case that a gradation value “1” of non-dot is realized, “0” is applied to a switcher for a time period during which the first to third pulses are generated. On the other hand, “1” is applied to the switcher in synchronism with the generation of the fourth pulse in order that only the fourth pulse for vibrating a meniscus of ink in the nozzle is applied to a piezoelectric vibrator. As a result, the gradation value “1” of the non-dot may be realized in which an ink droplet is not jetted. To this end, after the 2-bit data (00) indicative of the gradation value 1 has been decoded into the 4-bit data (0001) by a decoder, the decoded 4-bit data is applied to the above-described switcher.
Similarly, in the case that the gradation value 2 of the small dot is realized, “0” is applied to the switcher for a time period during which the first pulse, the third pulse, and the fourth pulse are generated. On the other hand, when “1” is applied to the switcher in synchronism with the generation of the second pulse, only the second pulse is applied to the piezoelectric vibrator, so that the gradation value 2 can be realized by which the ink droplets equivalent to the small dot are jetted. In this case, after 2-bit data (01) indicative of the gradation value 2 is decoded into 4-bit data (0100) by the decoder, the decoded 4-bit data is applied to the above-explained switcher.
Similarly, in the case that the gradation value 3 of one middle dot is realized, “0” is applied to the switcher for a time period during which the second pulse, the third pulse, and the fourth pulse are generated. On the other hand, when “1” is applied to the switcher in synchronism with the generation of the first pulse, only the first pulse is applied to the piezoelectric vibrator, so that the gradation value 3 can be realized by which the ink droplets equivalent to the middle dot are jetted. In this case, after 2-bit data (10) indicative of the gradation value 3 is decoded into 4-bit data (1000) by the decoder, the decoded 4-bit data is applied to the above-explained switcher.
Similarly, in the case that the gradation value 4 of two middle dots is realized, “0” is applied to the switcher for a time period during which the second pulse, and the fourth pulse are generated. On the other hand, when “1” is applied to the switcher in synchronism with the generations of the first and third pulses, only the first and third pulses are applied to the piezoelectric vibrator, so that the gradation value 4 can be realized by which the ink droplets equivalent to the middle dot are jetted two times. In this case, these ink droplets are continuously impacted onto the recording paper, and these ink droplets are mixed with each other, so that actually one large dot may be formed. Accordingly, the gradation value 4 can be realized. In this case, after 2-bit data (11) indicative of the gradation value 4 is decoded into 4-bit data (1010) by the decoder, the decoded 4-bit data is applied to the above-explained switcher.
On the other hand, in a head drive circuit mounted in the printing head of the ink jet printer, transmission gates (will be referred to as “TG” hereinafter) are provided in correspondence with every nozzle row used to jet each of the color ink droplets, while these TGs are constructed of switchers used to supply drive signals to the piezoelectric vibrators.
In order to execute the above-described dot gradation, for example, 2-bit gradation (multi-gradation) data (00, 01, 10, 11) SI is required to be decoded into such a pulse selection signal which is made of 4-bit data (0001, 0100, 1000, 1010). Thus, both this 2-bit gradation data (jetting data) SI and program data (pattern data) SP for executing this decoding must be supplied to the switcher (TG) incorporated in the printing head.
In the related ink jet printer, the jetting data (00, 01, 10, 11) SI is supplied from a control unit incorporated in a printer main body into the switcher (TG) incorporated in the printing head with respect to each of the color nozzle rows (each of color TGs). On the other hand, as to the program data (pattern data) SP, commonly-used patterns are supplied to all of the color nozzle rows (each of color TGs).
In the related ink jet printer, since the jetting data SI for each of these color nozzle rows (namely, respective color TGs) is supplied to the switcher (TG) incorporated in the printing head from the control unit of the printer main body, signal lines for the jetting data SI for each of these color nozzle rows (respective color TGs) are required within an FFC (Flexible Flat Cable) which electrically connects the printer main body to the printing head. Furthermore, at least one signal line for the pattern data SP is required in this FFC.
To achieve higher printing speeds and also higher image qualities in ink jet printers, the following measure may be conceived. That is, nozzle rows (TGs) for the respective colors incorporated in printing heads are increased. As explained above, when a plurality of ICs (TGs) are mounted on the printing heads, a plurality of signal lines are furthermore required in correspondence with these plural ICs.
However, a plurality of such signal lines are required within the FFC, so that the width of this FFC would be widened, and thus, wire routing works would become difficult. In addition, since such signal lines are provided with respect to each of these TGs, if a total number of TGs is increased, then manu
Nguyen Lam
Pham Hai
Seiko Epson Corporation
LandOfFree
Ink jet printer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet printer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet printer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3234682