Facsimile and static presentation processing – Static presentation processing – Dot matrix array
Reexamination Certificate
1998-01-30
2001-05-01
Evans, Arthur G. (Department: 2722)
Facsimile and static presentation processing
Static presentation processing
Dot matrix array
C358S001180
Reexamination Certificate
active
06226100
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a data conversion apparatus, a data conversion method, a printing apparatus using the data conversion apparatus and print control method and, more particularly, to a data conversion apparatus for converting vertical and horizontal orientation of inputted data, a printing apparatus and print control method for performing printing by converting vertical and horizontal orientation of inputted image data.
A serial-scan-type printing apparatus forms an image on a print medium e.g., a print sheet, by scanning a printhead, having plural printing elements arranged in a direction parallel to a conveyance direction of the print medium, in a direction perpendicular to the conveyance direction of the print medium.
Image data, transferred by a host computer (hereinafter referred to as a host) connected to the printing apparatus, consists of pixels arrayed in line in the scanning direction of a printhead. The data having such arrays of pixels is called raster data. In order to transfer image data having such arrays to a printhead, the printing apparatus needs to convert the orientation (arrays) of pixels so as to be adapted to an array of printing elements of the printhead.
Conventionally, such raster-column conversion (hereinafter referred to as H-V conversion) is executed by a processing program which reads plural lines of image data out of a buffer memory and writes converted data back to the buffer while shifting the read data.
However, it has become a trend to perform the H-V conversion by DMA (direct memory access) processing along with demands for high-speed data processing performed by a high-speed printing apparatus. Moreover, to increase the print operation speed, a minimum track printing method has been suggested. According to the minimum track printing method, the current position and the next print occurrence position of a carriage incorporating a printhead are detected and the carriage is moved in the most efficient manner to reduce wasteful operation time.
However, in order to perform the minimum track printing, a buffer storing image data must be scanned to detect positions where printing operations occur and positions where printing operations do not occur within a carriage movable range. Conventionally, such detection required considerable time, interfering with the primary object, i.e. the high-speed printing operation.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above situation, and has as its object to provide a printing apparatus and print control method capable of performing H-V conversion at high speed and performing minimum track printing at high speed.
According to the present invention, the foregoing object is attained by providing a printing apparatus for performing printing on a print medium by reciprocally scanning a printhead, comprising: input means for externally inputting image data; converting means for converting vertical and horizontal orientation of the image data inputted by the input means by DMA processing while considering a print width of the printhead; detecting means for consecutively processing an output result of the DMA processing and detecting a left end and a right end, where actual print operation is to be generated by the image data, within a scan area of the printhead; and control means for controlling the scan area of the printhead based on a detection result detected by the detecting means.
Furthermore, it is preferable that the apparatus includes storage means for storing the image data inputted by the input means and image data converted by the converting means.
Herein, each pixel of the image data is arrayed in a scanning direction of the printhead, and the image data converted by the converting means is arrayed along an array of printing elements of the printhead.
Moreover, it is preferable that the converting means executes conversion in units of a pixel length corresponding to the print width of the printhead.
It is preferable that the control means controls the printhead such that the printhead scans only between the left end and the right end where actual print operation is generated by the image data.
In addition, it is preferable that the detecting means initializes a detection value detected by said detecting means such that an initialized value can be discriminated from a value which may actually be detected, each time the left end and right end are detected for image data corresponding to a single scan of the printhead. Furthermore, values of the left end and the right end detected by the detecting means may represent storage addresses of image data which generate print operation at the left end and the right end of the scan area by the printhead, among the image data, corresponding to a single scan of the printhead, converted by the converting means and stored in the storage means.
Still further, it is preferable that the apparatus includes count means for counting an amount of the image data which generates actual print operation by the printhead, based on the image data, corresponding to a single scan of the printhead, converted by the converting means.
Note that the printhead may be an ink-jet printhead which performs printing by discharging ink, or may be a printhead for discharging ink by utilizing heat energy, and includes heat energy transducers for generating heat energy to be applied to the ink.
According to another aspect of the present invention, the foregoing object is attained by providing a print control method of a printing apparatus for performing printing on a print medium by reciprocally scanning a printhead, comprising: an input step of externally inputting image data; a converting step of converting vertical and horizontal orientation of the image data inputted in the input step by DMA processing while considering a print width of the printhead; a detecting step of consecutively processing an output result of the DMA processing and detecting a left end and a right end, where actual print operation is to be generated by the image data, within a scan area of the printhead; and a control step of controlling the scan area of the printhead based on a detection result detected in the detecting step.
According to the present invention as described above, at the time of printing an image on a print medium by reciprocally scanning a printhead, image data is externally inputted; vertical and horizontal orientation (arrays) of the inputted image data is converted by DMA processing, with considering a print width of the printhead; the output result of the DMA processing is continuously processed; a left end and a right end of image data in which actual print operation occur are detected within the scan area of the printhead; and on the basis of the detection result, the scan area of the printhead is controlled.
The present invention is particularly advantageous since the minimum track printing can be performed at high speed.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.
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Murata Takayuki
Omo Shinichi
Umezawa Masahiko
Canon Kabushiki Kaisha
Evans Arthur G.
Fitzpatrick ,Cella, Harper & Scinto
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