A liquid discharge apparatus, a method of discharging liquid, and a recording medium storing a program for causing a computer to execute the method. The liquid discharge apparatus and the method includes obtaining image data to be printed, performing dithering to achieve masking and halftone processing on the image data to generate print data, and controlling movement of a discharge head and discharge of ink based on the print data. The controlling includes increasing a ratio of a number of ink dots continuously discharged onto a recording medium in a grayscale on a shadow side to a total number of ink dots discharged onto the recording medium in one-time scanning by the discharge head in one line to be greater than a ratio of a number of ink dots continuously discharged onto the recording medium in a grayscale on a highlight side to the total number of ink dots.

Multiple first gradation values corresponding respectively to the multiple inks are quantized to generate multiple first quantized values indicating printing or non-printing of dots with the respective inks. In this case, multiple second gradation values corresponding respectively to multiple multinary colors expressible by combinations of overlapping of the multiple inks are generated based on the first gradation values. Next, the multiple second gradation values are quantized to generate multiple second quantized values indicating printing or non-printing of dots of the respective multinary colors. Then, the first quantized values corresponding to the inks to be overlapped one on top of another to express the multinary colors are generated based on the second quantized values corresponding respectively to the multiple multinary colors.

A liquid discharge apparatus, a method of discharging liquid, and a recording medium storing a program for causing a computer to execute the method. The liquid discharge apparatus and the method includes obtaining image data to be printed, performing dithering to achieve masking and halftone processing on the image data to generate print data, and controlling movement of a discharge head and discharge of ink based on the print data. The controlling includes increasing a ratio of a number of ink dots continuously discharged onto a recording medium in a grayscale on a shadow side to a total number of ink dots discharged onto the recording medium in one-time scanning by the discharge head in one line to be greater than a ratio of a number of ink dots continuously discharged onto the recording medium in a grayscale on a highlight side to the total number of ink dots.

An object is to save a user's trouble in a case of printing correction charts and stabilization charts and performing automatic tone correction with the correction charts among the printed charts. An image processing apparatus performs: control for printing correction chart images along with identification images for respectively identifying the correction chart images on print media in a one-to-one correspondence; and control for printing a stabilization chart image on a print medium before the control for printing the correction chart images. Then, from among scan images obtained by reading correction charts and one or more stabilization charts, the apparatus identifies the scan images respectively corresponding to the correction charts based on the identification images appearing in the scan images, the correction charts each being obtained by printing a correction chart image along with the corresponding identification image, the stabilization charts each being obtained by printing the stabilization chart image.

Multiple first gradation values corresponding respectively to the multiple inks are quantized to generate multiple first quantized values indicating printing or non-printing of dots with the respective inks. In this case, multiple second gradation values corresponding respectively to multiple multinary colors expressible by combinations of overlapping of the multiple inks are generated based on the first gradation values. Next, the multiple second gradation values are quantized to generate multiple second quantized values indicating printing or non-printing of dots of the respective multinary colors. Then, the first quantized values corresponding to the inks to be overlapped one on top of another to express the multinary colors are generated based on the second quantized values corresponding respectively to the multiple multinary colors.

A method of printing an image using a printing system having first and second printheads supplied with a same ink. The method includes the steps of: allocating first lines of the image to the first printhead; allocating second lines of the image to the second printhead; dithering the first lines of the image using a selected first dither mask; dithering the second lines of the image using a selected second dither mask; printing the dithered first lines of the image using the first printhead; and printing the dithered second lines of the image using the second printhead. The first and second dither masks are selected based on a relative alignment of the first and second printheads.

An image forming apparatus receive light from an intermediate transfer member or correction pattern. The pattern includes an overlapping pattern on which a first monochromatic toner image is formed as a lower layer and a second monochromatic toner image having a smaller area than the first monochromatic toner image is formed as an upper layer. The image forming apparatus controls a plurality of image forming units to form the overlapping pattern such that a dynamic range becomes less than 1.0 and larger than 0.5.

A method of single-pass printing uses a printing system having first and second aligned printheads supplied with a same ink. The method includes the steps of: receiving first and second halftone images at the first and second printheads, respectively; printing the first halftone image from the first printhead; and printing the second halftone image from the second printhead. The first halftone image is based on a first dither pattern and the second halftone image is based on a second dither pattern, the first dither pattern being different than the second dither pattern.

A method of screening a continuous-tone image is configured to produce an output image to be printed on a surface. The continuous-tone image comprises a plurality of pixels having respective corresponding intended print locations. The method includes selecting a first sequence comprising a subset of the plurality of intended print locations, the first sequence being selected based on properties of the plurality of intended print locations. For each intended print location in the first sequence, the method also includes identifying the corresponding pixel in the continuous-tone image to obtain a second sequence for an error diffusion process comprising the identified corresponding pixels in the continuous-tone image.

Formed is a dither pattern that makes it possible to output an image with excellent dot dispersibility and reduced graininess regardless of controls after quantization processing. To this end, an extended pattern in which multiple divided pixels correspond to each of multiple pixels included in quantization data and one or more of the multiple divided pixels are determined as dot-arrangeable-pixels in which dots can be printed is generated. Thereafter, the thresholds of the dither pattern are set based on the extended pattern in which the dots are arranged to obtain predetermined dispersibility.