Image forming apparatus that adjusts relative positions of images by detecting test pattern

Patent metadata

Field	Value
Publication number	US-2017038718-A1
Application number	US-201615222246-A
Country	US
Kind code	A1
Filing date	Jul 28, 2016
Priority date	Aug 3, 2015
Publication date	Feb 9, 2017
Grant date	—

Abstract

An image forming apparatus includes: a detection unit configured to detect a test pattern formed on an image carrier by image forming units; and an adjustment unit configured to control the image forming units to form the test pattern, and adjust relative positions of images based on a detection result of the test pattern. The adjustment unit is further configured to control the image forming units to form the test pattern after the image forming units has formed on the image carrier an image to be transferred to a sheet with a basis weight smaller than a threshold, and before the image forming units form on the image carrier an image to be transferred to a sheet with a basis weight larger than the threshold.

First claim

What is claimed is:

1 . An image forming apparatus, comprising:
an image forming unit configured to form an image by overlapping a first image and a second image, the image forming unit including a first image forming unit configured to form the first image using toner of a first color, and a second image forming unit configured to form the second image using toner of a second color that is different from the first color; an image carrier configured to carry the image formed by the image forming unit; a transfer unit configured to transfer the image carried by the image carrier to a sheet; a detection unit configured to detect a test pattern including a first detection image and a second detection image that have been formed on the image carrier by the first image forming unit and the second image forming unit, respectively; and an adjustment unit configured to control the first image forming unit and the second image forming unit to form the test pattern, and adjust relative positions of the first image and the second image based on a detection result of the test pattern by the detection unit, wherein the adjustment unit is further configured to control the image forming unit to form the test pattern after the image forming unit has formed on the image carrier an image to be transferred to a sheet with a basis weight smaller than a threshold, and before the image forming unit forms on the image carrier an image to be transferred to a sheet with a basis weight larger than the threshold.

2 . The image forming apparatus according to claim 1 , wherein
the adjustment unit is further configured to, when the image forming unit continuously forms a plurality of images, control the image forming unit to form the test pattern after at least one of the plurality of images that is to be transferred to a sheet with a basis weight smaller than the threshold has been formed on the image carrier, and before at least one of the plurality of images that is to be transferred to a sheet with a basis weight larger than the threshold is formed on the image carrier.

3 . The image forming apparatus according to claim 1 , further comprising
a driving unit that is driven to move the image carrier, wherein the driving unit is controlled in such a manner that a moving speed of the image carrier matches a predetermined moving speed in a state where the image to be transferred to the sheet with the basis weight larger than the threshold is carried by the image carrier, and the driving unit is controlled in such a manner that the moving speed of the image carrier matches the predetermined moving speed in a state where the image to be transferred to the sheet with the basis weight smaller than the threshold is carried by the image carrier.

4 . The image forming apparatus according to claim 1 , wherein
the adjustment unit is further configured to control the image forming unit to form another test pattern in a region between images that neighbor each other in a direction of movement of the image carrier while the image forming unit is forming a plurality of images to be transferred to sheets with basis weights smaller than the threshold.

5 . The image forming apparatus according to claim 4 , wherein
a length of a region in which the test pattern is formed in the direction of movement of the image carrier is larger than a length of the region in which the other test pattern is formed in the direction of movement.

6 . The image forming apparatus according to claim 1 , wherein
the adjustment unit is further configured to, along with the formation of the test pattern by the first image forming unit and the second image forming unit, control the image forming unit to suspend formation of an image to be transferred to a sheet on the image carrier until the adjustment of the relative positions of the first image and the second image is completed.

7 . The image forming apparatus according to claim 1 , further comprising
a second detection unit configured to detect a sheet at a position that is upstream, along a sheet conveyance path, relative to a transfer position at which the transfer unit performs transfer to the sheet, wherein the basis weight of the sheet is determined from a detection result by the second detection unit.

8 . An image forming apparatus, comprising:
a plurality of image forming units configured to form images, each having a different color; an intermediate transfer member to which the images formed by the plurality of image forming units are transferred; a detection unit configured to detect a color pattern formed on the transfer member, the color pattern being used for detecting color misregistration; a controller configured to:
control the plurality of image forming units to form a first plurality of color patterns, each having a difference color, on the intermediate transfer member,
control the detection unit to detect a first amount of color misregistration, related to a relative position of a color pattern having a reference color among the first plurality of color patterns and a color pattern having another color among the first plurality of color patterns, and
determine a correction value for adjusting an image write start timing of the other color different from the reference color based on the first amount of color misregistration detected by the detection unit; and
an obtaining unit configured to obtain information related to the sheet, wherein the controller is further configured to, in a case where the plurality of image forming units continuously form a first image and a second image that are to be transferred respectively to a first sheet and a second sheet based on a print job, control the plurality of image forming units to form a second plurality of color patterns, each having a different color, wherein the second plurality of color patterns are formed in between the first image and the second image on the intermediate transfer member, wherein the controller further configured to control the detection unit to detect a second amount of color misregistration, related to a relative position of a color pattern having a reference color among the second plurality of color patterns and a color pattern having another color among the second plurality of color patterns, and determine the correction value based on the second amount of color misregistration detected by the detection unit wherein a basis weight of the first sheet is smaller than a predetermined basis weight, and wherein a basis weight of the second sheet is larger than the predetermined basis weight.

9 . The image forming apparatus according to claim 8 , wherein
the intermediate transfer member conveys the images, and a length of the second plurality of color patterns formed on the intermediate transfer member in a direction of the conveyance of the images by the intermediate transfer member is larger than a length of the first plurality of color patterns formed on the intermediate transfer member in the direction of the conveyance.

10 . The image forming apparatus according to claim 8 , wherein
the controller is further configured to control the plurality of image forming units to form the first plurality of color patterns in a case where an amount of change in an internal temperature of the image forming apparatus reaches a predetermined amount.

11 . The image forming apparatus according to claim 8 , wherein
the controller is further configured to control the plurality of image forming units to form the first plurality of color patterns in a case where a number of printed sheets reaches a predetermined number while the plurality of image forming units are continuously forming image

Assignees

• Canon Kk

Inventors

• Tajiri Tsuyoshi
• Kishi Takehiro
• Tajima Hirotoshi

Classifications

• G03G15/0131 Primary

  for transferring a pattern to a second base · CPC title

• G03G15/0189

  primary transfer to an intermediate transfer belt (G03G15/0184 takes precedence) · CPC title

• G03G15/5058

  using a test patch · CPC title

• G03G15/6591

  characterised by the recording material, e.g. plastic material, OHP, ceramics, tiles, textiles (details transferring the toner pattern onto particular materials G03G15/1625) · CPC title

• G03G15/50 Primary

  Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control (sequencing control G03G21/14) · CPC title