Image forming apparatus having function for automatically adjusting image forming condition

A method for adjusting image forming conditions in an image forming apparatus, the image forming apparatus including a plurality of image forming units that are provided along a transfer medium, a plurality of sensors that each correspond to a different image forming unit and detect a density of an image that has been formed by a corresponding image forming unit and transferred onto the transfer medium, an adjustment unit for adjusting the image forming conditions of each image forming unit according to detection values produced by the sensors, the image forming method comprising steps of:

• having an image forming unit positioned furthest upstream with respect to a movement direction of the transfer medium form a standard image and transfer the standard image onto to transfer medium;
• having each sensor read the standard image on the transfer medium;
• and
• correcting, according to detection values produced when the sensors read the standard image, the detection values produced by the sensors that are used by the adjustment unit to adjust the image forming conditions.

A method for adjusting image forming conditions in an image forming apparatus, the image forming apparatus including a plurality of image forming units that arc provided along a transfer medium, a plurality of sensors that each correspond to a different image forming unit and detect a density of an image that has been formed by a corresponding image forming unit and transferred onto the transfer medium, an adjustment unit for adjusting the image forming conditions of each image forming unit according to detection values produced by the sensors, the image forming method comprising steps of:

• having a standard image formed by an image forming unit, out of the plurality of images forming units, positioned furthest upstream in a movement direction of the transfer medium;
• transferring the formed standard image onto the transfer medium;
• having the transferred standard image read by each sensor to produce a detection value for each sensor;
• correcting values outputted by each sensor based on the detection value produced by the sensor;
• and
• setting the image forming conditions of each image forming unit based on the corrected values outputted by the sensor corresponding to the image forming unit.

An image forming apparatus, comprising:

• a plurality of image forming units, each of which has an image holder and forms an image on the image holder according to set image forming conditions;
• a transfer unit for transferring images formed by each image forming unit onto a transfer medium or a recording medium carried by the transfer medium;
• a control unit for having the transfer unit transfer a standard image formed by each image forming unit onto the transfer medium so that the standard images do not overlap each other, and then transfer each of the standard images onto the recording medium so that the standard images do not overlap each other;
• a plurality of sensors, each of which is located near a different image forming unit and detects a density of the standard image transferred from a proximate image forming unit onto the transfer medium;
• an adjustment unit for adjusting the image forming conditions of each image forming unit according to a detection value produced by each sensor;
• an image reading unit for reading the standard images formed on the recording medium and detecting density of each of the standard images;
• and
• a sensitivity adjustment unit for adjusting sensitivity of each of the plurality of sensors based on a difference between the density of each of the standard images formed on the recording medium and detected by the image reading unit, and the density of each of the standard images formed on the transfer medium and detected by each of the plurality of sensors.

A method for adjusting image forming conditions in an image forming apparatus, the image forming apparatus including a plurality of image forming units that are provided along a transfer medium, a plurality of sensors that each corresponds to a different image forming unit and detects a density of an image that has been formed by a corresponding image forming unit and transferred onto the transfer medium, an adjustment unit for adjusting the image forming conditions of each image forming unit according to detection values produced by the sensors, and an image reading unit for reading images formed by each image forming unit and transferred onto a recording medium carried on the transfer medium and detecting density of each of the images, the image forming method comprising steps of:

• having each image forming unit form a standard image and transfer the standard image onto to transfer medium, the standard images on the transfer medium not overlapping each other;
• having each sensor read the standard image on the transfer medium;
• having each image forming unit form the standard images and transfer the standard images onto to the recording medium carried on the transfer medium, the standard images on the recording medium not overlapping each other;
• having the image reading unit read the standard images formed on the recording medium and detect density of each of the standard images;
• and
• adjust the sensitivity of each sensor based on a difference between the density of each of the standard images formed on the recording medium and detected by the image reading unit, and the density of each of the standard images formed on the transfer medium and detected by each sensor.