US 6,188,489 B1Granted

Image forming apparatus

AssigneeKabushiki Kaisha Toshiba

InventorKeiko Kanamori

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Abstract

In order to reduce the storage capacity of a memory for a density adjusting table and change the density adjustment range with a relatively high degree of freedom, a density characteristic adjusting table section corresponding to set density based on reference data of light, center and dark for density characteristic adjustment previously stored in a correction data table section is created in a table forming section, a density characteristic adjustment value corresponding to an input image signal from a scanner section is derived by effecting the linear interpolation according to neighboring density characteristic adjustment values based on the input image signal in a density characteristic adjustment value calculating section, and the input image signal is corrected by use of the derived density characteristic adjustment value in a density characteristic adjusting section and then output to a printer section as an output image signal.

Claims18

Dependent claims

An image forming apparatus comprising:

generation means for generating an input image signal;
setting means for setting output density of an output image signal to be formed in accordance with the input image signal;
storage means for storing first density curve data representing a first relation between density of the input image signal and first density of the output image signal, second density curve data representing a second relation between the density of the input image signal and second density of the output image signal, a third density curve data representing a third relation between density of the input image signal and third density of the output image signal, the second density being higher than the first density and the third density being higher than the second density;
creation means for creating fourth density curve data representing a fourth relation between the density of the input image signal and a fourth density of the output image signal, based on given two density curve data among the first, second, and third density curve data in accordance with the output density set by said setting means;
conversion means for converting the input image signal generated by said generating means into the output image signal having a density determined by the fourth density curve data;
and
image forming means for forming an output image on an image recording medium based on the output image signal converted by said conversion means,
wherein said creation means includes means for forming a density characteristic adjusting table for correcting the input image signal in said conversion means, said density characteristic adjusting table being formed by use of said first to third density curve data in which density characteristic adjustment values correspond to reference densities of the input image signal obtained by equally dividing a range of the input image signal.

5 more elements

An image forming apparatus comprising:

generation means for generating an input image signal;
setting means for setting output density of an output image signal to be formed in accordance with the input image signal;
storage means for storing first density curve data representing a first relation between density of the input image signal and first density of the output image signal, second density curve data representing a second relation between the density of the input image signal and second density of the output image signal, and third density curve data representing a third relation between density of the input image signal and third density of the output image signal, the second density being higher than the first density and the third density being higher than the second density;
creation means for creating fourth density curve data representing a fourth relation between the density of the input image signal and a fourth density of the output image signal, based on given two density curve data among the first, second, and third density curve data in accordance with the output density set by said setting means;
conversion means for converting the input image signal generated by said generating means into the output image signal having a density determined by the fourth density curve data;
and
image forming means for forming an output image on an image recording medium based on the output image signal converted by said conversion means,
wherein said creation means includes means for forming a density characteristic adjusting table for correcting the input image signal in said conversion means, said density characteristic adjusting table being formed by use of said first to third density curve data in which density characteristic adjustment values correspond to reference densities obtained by equally dividing a range of the density characteristic adjustment values.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/400,916Filed 22 Sep 1999 · continuation
Priority: JP 8-17044628 Jun 1996
Granted: 13 Feb 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G03G 15/5025
Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode…: by…
H04N 1/407
Picture signal circuits: control or modification of tonal gradation or of extreme levels, e.g. background level
G03G
Electrography
H04N
Pictorial communication