Image forming apparatus and recording medium
An image forming apparatus includes, an image former that forms an image in a plurality of colors on a sheet by an intermediate transfer method; and a hardware processor that acquires sheet attribute information indicating an attribute of the sheet, wherein, the hardware processor measures a color misregistration amount at a predetermined position in a surface of the sheet on which the image is formed by the image former; and the hardware processor performs control for correcting at least the color misregistration on the surface of the sheet, based on the acquired sheet attribute information and the measured color misregistration amount.
1 . An image forming apparatus comprising:
an image former that forms an image in a plurality of colors on a sheet by an intermediate transfer method, the image including a chart for measuring a color misregistration amount during image formation by the image forming apparatus;
a hardware processor that acquires sheet attribute information indicating one selected from the group consisting of basis weight of the sheet, size of the sheet, paper type of the sheet, stiffness of the sheet, moisture content of the sheet, surface smoothness of the sheet, surface evenness of the sheet, specific gravity of the sheet, and conductivity of the sheet; and
a detector located on a downstream side of the image former in a sheet conveyance direction, the detector being configured to detect the image formed on the sheet,
wherein,
the hardware processor measures the color misregistration amount at a predetermined position in a surface of the sheet on which the chart is formed by the image former, the measurement of the color misregistration amount being performed based on the chart formed on the sheet by the image former and detected by the detector;
the hardware processor performs control for correcting at least the color misregistration on the surface of the sheet, based on the acquired sheet attribute information and the measured color misregistration amount; and
the hardware processor determines, based on the acquired sheet attribute information, a number of patch or patches included in the chart, an arrangement positions of the patch or patches and a shape of a pattern included in the patch or patches corresponding to a maximum color misregistration amount assumed from the sheet attribute information.
2 . The image forming apparatus according to claim 1 , wherein,
the image former includes,
a registration part that conveys the sheet to a transferer that transfers an image onto the sheet, and
a fixer that fixes the image to the sheet, and
the hardware processor corrects the color misregistration by adjusting a conveyance speed in the registration part and a conveyance speed in the fixer.
3 . The image forming apparatus according to claim 2 , wherein the hardware processor measures the color misregistration amount after adjustment of the conveyance speed in the registration part and the conveyance speed in the fixer.
4 . The image forming apparatus according to claim 3 , wherein the hardware processor corrects, by image deformation processing, the color misregistration amount after the adjustment of the conveyance speed in the registration part and the conveyance speed in the fixer.
5 . The image forming apparatus according to claim 1 , wherein the hardware processor performs image deformation processing to correct color misregistration.
6 . The image forming apparatus according to claim 1 , wherein the hardware processor measures an integral value of the color misregistration amount among the plurality of colors as the color misregistration amount.
7 . The image forming apparatus according to claim 1 , wherein the hardware processor measures a maximum value of the color misregistration amount among the plurality of colors as the color misregistration amount.
8 . The image forming apparatus according to claim 1 , further comprising a storage that stores a correction value to correct the color misregistration for each attribute of the sheet.
9 . The image forming apparatus according to claim 1 , wherein the hardware processor acquires the sheet attribute information from a sensor.
10 . The image forming apparatus according to claim 1 , wherein,
the image former includes,
a registration part that conveys the sheet to a transferer that transfers an image onto the sheet, and
a fixer that fixes the image to the sheet, and
the hardware processor corrects the color misregistration by adjusting a conveyance speed in the registration part.
11 . The image forming apparatus according to claim 10 , wherein the hardware processor measures the color misregistration amount after adjustment of the conveyance speed in the registration part.
12 . The image forming apparatus according to claim 11 , wherein the hardware processor corrects, by image deformation processing, the color misregistration amount after the adjustment of the conveyance speed in the registration part.
13 . The image forming apparatus according to claim 1 , wherein,
the image former includes,
a registration part that conveys the sheet to a transferer that transfers an image onto the sheet, and
a fixer that fixes the image to the sheet, and
the hardware processor corrects the color misregistration by adjusting a conveyance speed in the fixer.
14 . The image forming apparatus according to claim 13 , wherein the hardware processor measures the color misregistration amount after adjustment of the conveyance speed in the fixer.
15 . The image forming apparatus according to claim 14 , wherein the hardware processor corrects, by image deformation processing, the color misregistration amount after the adjustment of the conveyance speed in the fixer.
16 . The image forming apparatus according to claim 1 , wherein the detector is at least one of:
a color information detection device configured to detect color information of the sheet conveyed from the image former and output the obtained detection result to the hardware processor, and
an image reading device configured to read the sheet conveyed from the image former and output the obtained read image to the hardware processor.
17 . The image forming apparatus according to claim 1 , wherein
the patch is at least one of:
a first patch in which rectangular patterns formed of black or white at both ends and
single toners of at least two of yellow, magenta and cyan between the both ends are arranged in a line;
a second patch including two of the first patches orthogonal to each other;
a third patch including rectangular patterns each formed with single toners of yellow, magenta, and cyan surrounded by black;
a fourth patch including halftone rectangular patterns formed with single toners of yellow, magenta, cyan, and black, wherein the halftone rectangular patterns overlap each other without deviation in an original image data of the fourth patch, and the halftone rectangular patterns overlap each other while being shifted by the color misregistration amount when a color misregistration occurs at the time of forming the fourth patch;
a fifth patch including a plurality of first units each including a first pattern formed with one of yellow, magenta or cyan toner located on a downstream side in the sheet conveyance direction, and having an upwardly convex shape when the sheet conveyance direction is defined as an upward direction, a second pattern formed with another one of yellow, magenta or cyan toner located on a upstream side in the sheet conveyance direction, and having a downwardly convex shape when the sheet conveyance direction is defined as the upward direction, and a third pattern formed of a concealing color toner, and superimposed on the first pattern and the second pattern so as to cover the first pattern and the second pattern;
a sixth patch including a plurality of second units each including a fourth pattern formed with one of yellow, magenta or cyan toner located on the downstream side in the sheet conveyance direction, and having the downwardly convex shape, a fifth pattern formed with another one of yellow, magenta or cyan toner located on the upstream side in the sheet conveyance direction, and having the upwardly convex shape, and a sixth pattern formed of the concealing color toner, and superimposed on the fourth pattern and the fifth pattern so as to cover the fourth pattern and the fifth pattern; or
a seventh patch including a plurality of third units each including a seventh pattern formed with one of yellow, magenta or cyan toner located on the downstream side in the sheet conveyance direction, and having a rectangular shape, an eighth pattern formed with another one of yellow, magenta or cyan toner located on the upstream side in the sheet conveyance direction, and having a rectangular shape, and a ninth pattern formed of the concealing color toner, and superimposed on the seventh pattern and the eighth pattern so as to cover the seventh pattern and the eighth pattern.
18 . A non-transitory recording medium including a program that controls a computer of an image forming apparatus comprising an image former for forming images in a plurality of colors on a sheet by an intermediate transfer method to functions as:
a hardware processor that acquires sheet attribute information indicating one selected from the group consisting of basis weight of the sheet, size of the sheet, paper type of the sheet, stiffness of the sheet, moisture content of the sheet, surface smoothness of the sheet, surface evenness of the sheet, specific gravity of the sheet, and conductivity of the sheet,
wherein,
the image includes a chart for measuring a color misregistration amount during image formation by the image forming apparatus,
the hardware processor measures the color misregistration amount at a predetermined position in a surface of the sheet on which the chart is formed by the image former, the measurement of the color misregistration amount being performed based on the chart formed on the sheet by the image former and detected by a detector;
the hardware processor performs control to correct at least the color misregistration on the surface of the sheet based on the acquired sheet attribute information and the measured color misregistration amount; and
the hardware processor determines, based on the acquired sheet attribute information, a number of patch or patches included in the chart, an arrangement positions of the patch or patches and a shape of a pattern included in the patch or patches corresponding to a maximum color misregistration amount assumed from the sheet attribute information.