Utility Patent
1996-12-13
2001-01-02
Boudreau, Leo H. (Department: 2721)
C347S001000, C347S020000, C347S040000, C347S041000
Utility Patent
active
06168320
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a printing apparatus and method and, more particularly, to a printing apparatus for performing printing by scanning a region having a predetermined width once or a plurality of number of times using a printing head having a printing element array having the predetermined width in the feed direction of a printing medium, and a facsimile apparatus comprising the apparatus.
As a conventional printing apparatus, an ink-jet printing apparatus that performs printing by ejecting ink onto a printing medium to form an image is known. In general, in this printing method, a printing head constituted by arranging a plurality of nozzles, serving as a printing element array, in the feed direction of a printing medium to have a predetermined width is scanned in a direction (main scanning direction) perpendicular to the nozzle array, and the printing medium is fed in a direction (sub-scanning direction) perpendicular to the main scanning direction, thus performing printing on the printing medium. As described above, this printing method for completing printing corresponding to the printing width of the printing head by one scan without dividing the nozzle array of the printing head into a plurality of blocks will be referred to as a one-pass printing method.
As an application of this printing method, multipass printing is known. In this printing method, the nozzle array is divided into n nozzle regions (n is an integer equal to or larger than 2), and printing corresponding to the printing width of the printing head is completed by n scans using n different nozzle regions with respect to an identical printing region. More specifically, in the first scan, printing is performed by ejecting ink from the nozzles of the printing head and scanning the printing head in the main scanning direction. In the next scan, the printing medium is fed by a width 1
the nozzle array in the sub-scanning direction, and thereafter, printing is performed by further performing ink ejection onto the 1
region that has been subjected to the ink ejection in the previous scan, and similarly scanning the printing head. Furthermore, in the next scan, the printing medium is fed by a width 1
the nozzle array in the sub-scanning direction, and thereafter, printing is performed by further performing ink ejection onto the 1
region that has been subjected to the ink ejection in the two previous scans, and similarly scanning the printing head. By repeating the above-mentioned operation n times, printing corresponding to the printing width to be printed in one scan in one-pass printing is completed. At this time, image data obtained by processing (e.g., masking specific information of) the same image data to be used in printing in one-pass printing for multi-pass printing is used. With multi-pass printing, for example, the image quality of a gradation image can be improved.
However, in the case of, e.g., the conventional multi-pass recording in one recording apparatus, some nozzles are not used in actual printing on the first portion (the portion to be printed in the first scan) and the last portion (the portion to be printed in the last scan), resulting in an idle scanning region. For example, when n-pass printing (n is an integer equal to or larger than 2) is to be performed, each of the first and last scans upon printing the first and last portions of the printing region uses only a region corresponding to 1
nozzles of the printing head, and the remaining (n−1)
nozzle region scans a blank printing region that becomes an idle scanning region. Furthermore, the n-pass printing method requires a printing time n times that required for one-pass printing.
On the other hand, the scans for the first and last portions of the printing region often correspond to the leading and trailing end portions of a cut printing paper sheet, and the blank printing regions require extra margins on the printing start and end portions on the printing medium, resulting in a narrow printable range. Especially, as the printing head has a larger printing width, and the printing range for one scan increases, the blank printing region becomes broader, and consequently, the printable range is further narrowed.
In order to assure a broad printable range, a method of adjusting the position of the printing medium with respect to the printing head may be used. However, with this method, the printing medium must be moved and held by, e.g., rollers so that the leading end of the printing medium is located at the middle of the printing head on the leading end portion of the printing medium, and the trailing end of the printing medium is stopped at the middle of the printing head on the trailing end portion of the printing medium. With such apparatus arrangement, since the printing medium must be firmly held while assuring the moving space of the printing head, the mechanism is complicated considerably. When the mechanism for holding the printing medium is arranged in the apparatus, a large space is required in the apparatus (especially, in the holding portion of the printing medium), and consequently, the distance between the printing medium and the printing head undesirably becomes large.
In particular, when the printing head is an ink-jet printing head, if the distance between the printing medium and the printing head is large, the ink ejected from the printing head cannot land at desired positions on the printing medium, or the ink lands on the printing medium while being sprayed consequently, largely influencing on the image quality.
Also, it is mechanically difficult to hold the leading and trailing end portions of the printing medium, and the printing head may contact the leading or trailing end of a printing paper sheet, thus causing ink contamination or stains on the printing medium.
Furthermore, in the case of the printing apparatus used in printing of a facsimile apparatus, the leading end portion of the printing medium often has a margin or header information such as the transmission date, page, ID, and the like as a binary image to be added by the transmitting side, and the necessity of multi-pass printing such data from the leading end of the printing medium is low. Moreover, the trailing end portion of the printing medium often also has a footer mark or footer information such as time as a binary image, and the necessity of multi-pass printing is low in that portion.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above-mentioned problems, and has as its object to provide a printing apparatus and method, which can decrease the printing time loss, and a facsimile apparatus comprising the printing apparatus.
It is another object of the present invention to provide a printing apparatus and method, which can broaden the effective printing region to be printed by a printing head, and execute optimal printing corresponding to input image data, and a facsimile apparatus comprising the printing apparatus.
In order to achieve the above objects, a printing apparatus according to the present invention comprises the following arrangement.
That is, there is provided a printing apparatus for printing an image on a printing medium using a printing head having a printing element array with a predetermined width in a feed direction of the printing medium, comprising:
printing means for performing printing by scanning a region having the predetermined width on the printing medium a predetermined number of times (n≧2) using the printing head; and
control means for controlling the printing means so that the scanned region includes a printing region in which printing is completed by a smaller number of scans of the printing head than the predetermined number of times, upon printing in at least a first or last scan of the printing head.
In order to achieve the above object, a facsimile apparatus according to the present invention comprises the following arrangement.
That is, there is provided a facsimile apparatus which comprises a printing apparatus of clai
Kobayashi Makoto
Ono Takeshi
Boudreau Leo H.
Canon Kabushiki Kaisha
Desire Gregory
Fitzpatrick ,Cella, Harper & Scinto
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