Image processing apparatus

• US 5,586,227 A
• Filed: 03/20/1992
• Issued: 12/17/1996
• Est. Priority Date: 03/28/1991
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yamada, Hiromichi, Saito, Tetsuo, Mano, Hiroshi, Kashihara, Atsushi, Seto, Kaoru, Kawana, Takashi
• Primary Examiner(s): Bayerl, Raymond J.
• Assistant Examiner(s): Sax, Steven P.
• Application Number:
  US07/855,083
• Time in Patent Office: 1,733 Days
• Field of Search: 395/132, 395/109, 395/128, 395/100, 395/112, 395/117, 395/111, 395/114, 364/519
• US Class Current: 358/1.13
• CPC Class Codes: G06K 15/00 Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printersprinting or plotting combined with another operation, e.g. with conveying, G06K17/00
• CPC Class Codes: G06K 2215/006 Anti-aliasing raster data
• CPC Class Codes: G06K 2215/0077 Raster outputting to the print element(s)

Abstract

An image processing apparatus which generates an output image based on inputted print data, includes a resolution converting device which converts image data corresponding to the inputted print data at a first resolution into image data having a second resolution. The image conversion device includes a plurality of arithmetic processing units each of which performs computations which differ from the others, with one of the plurality of arithmetic processing unit being selected in dependence upon a recording density set for recording the output image. In other aspects, the resolution conversion computation can be input into the device from an external device. In situations where the generated output image is recorded on a pulse-width-modulated device, such as a laser beam printer, it is possible to control the pulse-width based on the density set for recording.

Claims

1. An image processing apparatus for generating an output image based upon inputted print data and delivering the output image to a prescribed recording device, comprising:

density setting means for setting a dark level of recording density;

input means for inputting binary print data intended to be printed at a first resolution;

resolution converting means for generating binary image data having a second resolution by splitting each pixel in image data, which is based upon the binary print data inputted by said input means, into a plurality of partial pixels and then applying a correction; and

output means for outputting the binary image data converted by said resolution converting means to the prescribed recording device;

said resolution converting means including;

a plurality of arithmetic means for computing the state of each individual partial pixel at the second resolution, wherein computations performed by individual arithmetic means differ from one another; and

selecting means for selecting one of said plurality of arithmetic means in dependence upon the dark level of recording density set by said density setting means.

2. The apparatus according to claim 1, wherein when said plurality of arithmetic means are such that when the state of each partial pixel of the second resolution corresponding to a pixel of interest is computed, the contents of processing of the states of a group of pixels at the first resolution in the vicinity of the pixel of interest are different.

3. The apparatus according to claim 1, wherein said plurality of arithmetic means are such that the higher the density set by said density setting means, the lower the probability that the individual partial pixels generated will be black.

4. The apparatus according to claim 1, wherein said prescribed recording device is a laser-beam printer, and said plurality of arithmetic means are such that the higher the density set by said density setting means, the shorter the ON time of laser emission for the individual partial pixels.

5. An image processing apparatus for generating an output image based upon inputting print data and printing the output image on a prescribed recording medium, comprising:

density setting means for setting a dark level of recording density;

input means for inputting binary print data intended to be printed at a first resolution;

resolution converting means for generating binary image data having a second resolution by splitting each pixel in image data, which is based upon the binary print data inputted by said input means, into a plurality of partial pixels and then applying a correction; and

printing means for printing the binary image data converted by said resolution converting means;

said resolution converting means including;

a plurality of arithmetic means for computing the state of each individual partial pixel at the second resolution, wherein computations performed by individual arithmetic means differ from one another; and

selecting means for selecting one of said plurality of arithmetic means in dependence upon the dark level of recording density set by said density setting means.

6. The apparatus according to claim 5, wherein when said plurality of arithmetic means are such that when the state of each partial pixel of the second resolution corresponding to a pixel of interest is computed, the contents of processing of the states of a group of pixels at the first resolution in the vicinity of the pixel of interest are different.

7. The apparatus according to claim 5, wherein said plurality of arithmetic means are such that the higher the density set by said density setting means, the lower the probability that the individual partial pixels generated will be black.

8. The apparatus according to claim 5, wherein said prescribed recording device is a laser-beam printer, and said plurality of arithmetic means are such that the higher the density set by said density setting means, the shorter the ON time of laser emission for the individual partial pixels.

9. An image processing apparatus comprising:

density setting means for setting a dark level of recording density;

generating means for generating a synchronizing clock signal in a main scanning direction;

input means for inputting binary image data, which has a first printing density, in synchronization with the synchronizing clock signal generated by said generating means;

memory means for storing a plurality of lines of the binary image data, inputted by said input means, in main-scanning units;

referring means for referring to the state of a pixel of interest and the states of pixels peripheral to the pixel of interest based upon the binary image data stored in said memory means;

a plurality of converting means for converting binary image data which corresponds to the pixel of interest to a plurality of binary image data of a second printing density higher than the first printing density based upon the results of reference performed by said referring means;

selecting means for selecting one item of binary image data, from among the plurality of binary image data converted by said plurality of converting means, based upon the dark level of recording density set by said density setting means; and

output means for outputting the binary image data of the second printing density selected by said selecting means.

10. The apparatus according to claim 9, wherein said output means includes pulse-width control means for controlling pulse widths of individual pixels, which constitute the image data of the second printing density selected by said selecting means, based upon the density set by said density setting means.

11. An image processing apparatus comprising:

density setting means for setting a dark level of recording density;

generating means for generating a synchronizing clock signal in a main scanning direction;

input means for inputting binary image data, which has a first printing density, in synchronization with the synchronizing clock signal generated by said generating means;

memory means for storing a plurality of lines of the binary image data, inputted by said input means, in main-scanning units;

referring means for referring to the state of a pixel of interest and to the states of pixels peripheral to the pixel of interest based upon the binary image data stored in said memory means;

converting means for converting binary image data which corresponds to the pixel of interest to a binary image data of a second printing density higher than the first printing density based upon the results of reference performed by said referring means;

pulse-width control means for controlling pulse width of each pixel, which is contained in the binary image data converted by said converting means, based upon the dark level of recording density set by said density setting means; and

output means for outputting the binary image data controlled by said pulse-width control means.

12. The apparatus according to claim 11, wherein said output means is a laser-beam printer which records the image by turning laser-beam irradiation on and off based upon a pulse-width signal controlled by said pulse-width control means.

13. An image processing apparatus for generating an output image based upon inputted print data and delivering the output image to a prescribed recording device, comprising:

input means for inputting binary image data;

memory means for storing a plurality of pixels located within a predetermined area of the binary image data inputted by said input means;

output-pixel generating means for generating an output pixel upon processing status information indicative of said plurality of pixels stored in said memory means;

wherein said output-pixel generating means generates an output pixel by converting one binary pixel data inputted by said input means into a plurality of binary pixel data;

output means for delivering the output pixel generated by said output-pixel generating means to the prescribed recording device;

second input means for externally inputting data of an algorithm of said processing in said output-pixel generating means; and

control means for performing control in accordance with the processing algorithm inputted by said second input means in such a manner that said output-pixel generating means generates an output pixel.

14. The apparatus according to claim 13, further comprising second memory means for storing a plurality of items of processing algorithm data inputted by said second input means;

said control means including selecting means for selecting one of the plurality of items of processing algorithm data stored in said second memory means, said control means performing control in such a manner that said output-pixel generating means generates an output pixel in accordance with the processing algorithm data selected by said selecting means.