Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-01-29
2001-08-07
Nguyen, Thinh (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S044000, C347S009000
Reexamination Certificate
active
06270188
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet printer and its control method, particularly to an ink jet printer and its control method in which when one dot is recorded with a plurality of colors of ink overlapping, ink blur is prevented from being generated in a recording sheet.
2. Description of the Related Art
In general, an ink jet printer is used as an output device of a computer, a word processor, or the like.
In a conventional ink jet printer, a carriage shaft is disposed in a direction parallel with a platen, and a reciprocatable carriage is disposed along the carriage shaft. Moreover, an ink jet recording head is mounted on the carriage to oppose the platen in such a manner that a head nozzle of the ink jet faces a printing face of the platen.
According to the above conventional ink jet printer, a recording sheet is conveyed between the platen and the ink jet head. While the carriage having the ink jet head mounted thereon moves along the platen, the nozzle of the ink jet head is operated on the basis of a predetermined printing signal, so that the desired ink is ejected or discharged from the nozzle toward the recording sheet on the platen. Thus, a desired image is recorded or printed on the recording sheet.
In such conventional ink jet printer, for example, yellow, magenta, cyan and black inks are used to perform full-color recording. In this case, when the yellow, magenta, cyan and black inks are all ejected from the respective nozzles to record a certain dot, the amount of ink ejected for one dot becomes remarkably large as a result. This causes a problem that the recorded dot blurs and becomes hazy or indistinct, resulting in the deterioration of the recording quality.
SUMMARY OF THE INVENTION
The present invention has been accomplished in consideration of the aforementioned circumstances, and a first object thereof is to provide an ink jet printer control method in which when a plurality of colors of ink are overlapped to record a dot, ink blur can be prevented from being generated in a recording sheet.
A second object of the present invention is to provide an ink jet printer which prevents occurrence of ink blur when a plurality of colors of ink are overlapped to record a dot on a recording sheet.
The first object of the present invention is attained by the provision of a control method of an ink jet printer having an ink jet head which ejects an ink droplet to record a dot on a recording sheet, the ink jet head being mounted on a carriage reciprocating in a direction substantially orthogonal to the conveying direction of the recording sheet. In the control method, when a plurality of colors of ink are overlapped to record a dot, each color ink ejection time period is set shorter as compared with when a single-color dot is recorded.
The first object of the invention is also attained by the provision of a control method of an ink jet printer having an ink jet head which ejects an ink droplet to record a dot on a recording sheet, the ink jet head being mounted on a carriage reciprocating in a direction substantially orthogonal to the conveying direction of the recording sheet, comprising the steps of:
dividing an ejection time width for recording one dot of ink ejected from said ink jet head into a plurality of pitches;
associating each pitch with an address of a timing data memory;
preparing timing data by storing data indicating plural ejection time lengths of said ink jet head in the address corresponding to ejection timing;
providing selection information for selecting any one of said plural ejection time lengths, said selection information being included in record data for each dot;
determining the ejection timing for each dot from said timing data on the basis of the ejection time length selected by the selection information of said record data; and
controlling each dot ink ejection time length by the determined ejection timing.
The timing data may include a plurality of ejection start signals stored in different addresses and one ejection end signal. The record data may include the selection information for selecting any one from the ejection start signals. With such construction, ink ejection can be started from the address of the ejection start signal selected by the selection information and completed at the address of the ejection end signal.
RAM (Random Access Memory) for recording the record data for one scanning operation may also be used as the timing data memory. Moreover, while the record data for one dot is read and written into a shift register, the timing data is read in the address order to obtain the ejection start timing, and the amount or color of ink corresponding to the record data is controlled to be ejected at the obtained ejection start timing. The record data may include information for setting different ink ejection time lengths for one dot, while the timing data may include a plurality of ejection timings different in the ejection time length.
For example, the record data may include long record data indicative of a long ejection time and short record data indicative of a short ejection time. The timing data may include long ejection start data for starting ejection early when performing the ink ejection in the long ejection time, short ejection start data for starting ejection late when performing the ink ejection in the short ejection time, and ejection end data indicating the end of the long or short ejection time.
When a plurality of ink jet heads are provided, the data indicative of the ejection timing for each ink jet head can be used for independently changing the address in the timing data memory to independently change the ejection timing for each ink jet head. Therefore, when the address for storing the data indicative of the ejection timing can be changed for each ink jet head, the ejection timing of each ink jet head can independently and easily be controlled, which is convenient.
According to the present invention, the second object is attained by the provision of an ink jet printer in which an ink jet head is mounted on a carriage reciprocating in a direction substantially orthogonal to the conveying direction of a recording sheet, comprising:
CPU for outputting record data including data indicating ink ejection time length for each dot;
a record data memory for sequentially storing a predetermined volume of record data while said ink jet head is moving along a recording path;
a timing data memory for dividing an ejection time length for recording one dot of ink ejected from said ink jet head into a plurality of pitches, associating each pitch with an address position, and storing data indicating plural ejection time lengths in an address corresponding to ejection timing;
a timing signal generating circuit for reading and outputting the record data for one dot from said record data memory, and for reading the ejection timing corresponding to the ejection time length indicated by said record data from said timing data memory to output an ejection signal at a predetermined ejection timing; and
a head driver for operating the ink jet head based on said record data for one dot and said ejection signal to eject the ink corresponding to said record data at said predetermined ejection timing.
The record data memory and the timing data memory may be shared for use by dividing the common memory (RAM or the like) into different storage areas for use. The record data of the ink jet head for one scanning operation is stored in the memory, and the record data is rewritten every time recording of one scanning operation is finished. Additionally, once the timing data is set, the same timing data is constantly used thereafter. When a plurality of, e.g., two memories are provided, the record data can be alternately rewritten corresponding to repetition of the scanning operation. In this case, while recording is performed by the ink jet head using one of the memories, next new record data can be written into the other memory. Therefore, data processing is smoothly performed, and pro
Hakkaku Kunio
Tandou Katsuyoshi
Fuji Photo Film Co. , Ltd.
Nguyen Thinh
Sughrue Mion Zinn Macpeak & Seas, PLLC
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