Multiple-color image output apparatus and method which prevents a toner image on a photosensitive drum from being narrowed in the horizontal direction

A multiple-color image output method for forming a color image by forming a latent image on a surface of an image bearing body by distributing an electric potential on the surface and successively superimposing visible developed images, which correspond to the latent image, of a plurality of color elements on a transfer member, comprising:

• an image generating step of generating a bitmap image in each color;
• a latent-image forming step of forming a latent image on said image bearing body by referring to a pixel of interest in the bitmap image and a group of pixels neighboring the pixel of interest and, if the pixel of interest is a white pixel and the group of pixels neighboring the pixel of interest includes a non-white pixel, forming the latent image corresponding to the pixel of interest on the image bearing body at a potential for which there is a prescribed difference relative to a potential corresponding to the white pixel and at which the latent image will not be rendered visible;
• and
• a developing step of developing the latent image on the image bearing body into a visible image.

A multiple-color image processing apparatus comprising:

• means for referring to data of a pixel of interest and of pixels neighboring the pixel of interest on a per color-component basis;
• means for determining, based upon the data referred to and on a per color-component basis, whether the pixel of interest includes a non-recording pixel and the neighboring pixels include recording pixels;
• and
• means for converting data of the pixel of interest to data of a third level between a first level corresponding to the non-recording pixel and a second level corresponding to a recording pixel in a case where the determination made by said determining means is affirmative.

A multiple-color image processing method comprising the step of:

• referring to data of a pixel of interest and of pixels neighboring the pixel of interest on a per color component basis;
• determining, based upon the data referred to and on a per color-component basis, whether the pixel of interest includes a non-recording pixel and the neighboring pixels include recording pixels;
• and
• converting data of the pixel of interest to data of a third level between a first level corresponding to the non-recording pixel and a second level corresponding to a recording pixel in a case where the determination made at said determining step is affirmative.

A multiple-color image forming apparatus for forming an image using a light-emitting element, comprising:

• first control means for causing the light-emitting element to emit light at a first light-emission quantity in regard to non-recording pixels, and each neighboring area of the non-recording pixels does not include any recording pixel;
• second control means for causing the light-emitting element to emit light at a second light-emission quantity greater than the first light-emission quantity in regard to recording pixels;
• and
• third control means for causing the light-emitting element to emit light at a third light-emission quantity between the first and second light-emission quantities in regard to non-recording pixels, and each neighboring area of the non-recording pixels includes a recording pixel.

A multiple-color image forming method for forming an image using a light-emitting element, comprising:

• a first control step of causing the light-emitting element to emit light at a first light-emission quantity in regard to non-recording pixels in a neighboring area;
• a second control step of causing the light-emitting element to emit light at a second light-emission quantity greater than the first light-emission quantity in regard to recording pixels;
• and
• a third control step of causing the light-emitting element to emit light at a third light-emission quantity between the first and second light-emission quantities in regard to non-recording pixels which include a recording pixel in the neighboring area.

A color image forming apparatus for forming a color image by overlaying a plurality of mono-color images which are formed by different color materials, comprising:

• a photosensitive drum;
• a light source for emitting light to expose said photosensitive drum;
• and
• converting means for converting image data representing an image to be formed into a modulation signal for modulating the light emitted from said light source,
• wherein, in a case that the image data represents an image in which a first area having a color of a first color material in a first density and a second area having a color of a second color material in a second density are closely arranged, said converting means converts the image data into the modulation signal so that, even if the first density or the second density is not a maximum density, an area, where neither the first nor the second color materials exists, is not formed in a boundary between the first and the second area.

A color image forming method of forming a color image by overlaying a plurality of mono-color images which are formed by different color materials, comprising the steps of:

• converting image data representing an image to be formed into a modulation signal for modulating light emitted from a light emitting source;
• and
• forming an image on a photosensitive drum by emitting light from the light source based upon the modulation signal,
• wherein, in a case that the image data represents an image in which a first area having a color of a first color material in a first density and a second area having a color of a second color material in a second density are closely arranged, then the image data is converted, in said conversion step, into the modulation signal so that, even if the first density or the second density is not a maximum density, an area, where neither the first nor the second color materials exists, is not formed in a boundary between the first and the second area.