Image forming device and method capable of high quality duplex printing

An image forming method comprising:

• setting an image forming order and image forming intervals when double-sided printing is carried out in which images are formed on first sides and second sides of a plurality of recording sheets;
• placing first images to be formed on the first sides of the recording sheets at positions in the order of image formation onto the recording sheets, and second images to be formed on the second sides of the recording sheets at positions determined in accordance with the positions where the images of the first sides are placed;
• judging whether or not a predetermined interval or more is needed between the respective placed first and second images and images which have already been placed and are adjacent to the placed first and second images, wherein it is judged that a predetermined interval or more is needed between one of the placed first and second images and an image that has already been placed and is adjacent to the one of the placed first and second images when a configuration of at least one of a plurality of developing sections is changed from a configuration for multi-color image formation to a configuration for single-color image formation or from a configuration for single-color image formation to a configuration for multi-color image formation during the time period between the time of formation of the one of the placed first and second images and the time of formation of the image that has already been placed and is adjacent to the one of the placed first and second images;
• if it is judged that the predetermined interval or more is needed, confirming whether or not the predetermined interval or more is maintained;
• if it is judged that the predetermined interval or more is not maintained, placing again a first image of the first side and a second image of the second side at positions where the predetermined interval is maintained;
• and
• carrying out image formation in the set image forming order while conveying the recording sheets on the basis of the set image forming intervals.

An image forming device comprising:

• an image forming section that forms an image on a recording sheet, the image forming section comprising a plurality of developing sections corresponding to a plurality of colors;
• and
• a setting section that sets an image forming order and image forming intervals when double-sided printing is carried out in which images are formed on first sides and second sides of a plurality of recording sheets, the image forming section carrying out image formation in the set image forming order while conveying the recording sheets on the basis of the image forming intervals set by the setting section,
• wherein, the setting section is adapted to
• form first images on the first sides of the recording sheets at positions in the order of image formation onto the recording sheets, the positions, where the first images to be formed on the first sides of the recording sheets can be placed, being set in advance, and
• form second images on the second sides of the recording sheets at positions determined in accordance with the positions where the second images of the first sides are placed,
• the setting section is further adapted to
• temporarily place a first image of the first side;
• temporarily place a second image of the second side at a position determined in accordance with the position of the first image of the first side;
• judge whether or not a predetermined interval or more is needed between the respective temporarily placed first and second images and images which have already been placed and are adjacent to the temporarily placed first and second images;
• the setting section judging that a predetermined interval or more is needed between one of the temporarily placed first and second images and an image that has already been temporarily placed and is adjacent to the one of the temporarily placed images when a configuration of at least one of the developing sections is changed from a configuration for multi-color image formation to a configuration for single-color image formation or from a configuration for single-color image formation to a configuration for multi-color image formation during the time period between the time of formation of the one of the temporarily placed first and second images and the time of formation of the image that has already been temporarily placed and is adjacent to the one of the temporarily placed first and second images;
• confirm whether or not the predetermined interval or more is maintained if it is judged that the predetermined interval or more is needed;
• temporarily place again a first image of the first side and a second image of the second side if it is judged that the predetermined interval or more is not maintained;
• and
• set the temporary placement positions as placement positions of the first image of the first side and the second image of the second side if it is judged that the predetermined interval or more is not needed or if it is judged that the predetermined interval or more is maintained.

An image forming method comprising:

• setting an image forming order and image forming intervals when double-sided printing is carried out in which images are formed on first sides and second sides of a plurality of recording sheets;
• and
• carrying out image formation in the set image forming order while conveying the recording sheets on the basis of the set image forming intervals,
• wherein, when placing first images to be formed on the first sides of the recording sheets at positions in the order of image formation onto the recording sheets, the positions, where the first images to be formed on the first sides of the recording sheets can be placed, being set in advance, and second images to be formed on the second sides of the recording sheets at positions determined in accordance with the positions where the first images of the first sides are placed,
• temporarily placing a first image of the first side;
• temporarily placing a second image of the second side at a position determined in accordance with the position of the image of the first side;
• judging whether or not a predetermined interval or more is needed between the respective temporarily placed first and second images and images which have already been placed and are adjacent to the temporarily placed first and second images, wherein it is judged that a predetermined interval or more is needed between one of the temporarily placed first and second images and an image that has already been temporarily placed and is adjacent to the one of the temporarily placed first and second images when a configuration of at least one of a plurality of developing sections is changed from a configuration for multi-color image formation to a configuration for single-color image formation or from a configuration for single-color image formation to a configuration for multi-color image formation during the time period between the time of formation of the one of the temporarily placed first and second images and the time of formation of the image that has already been temporarily placed and is adjacent to the one of the placed first and second images;
• if it is judged that the predetermined interval or more is needed, confirming whether or not the predetermined interval or more is maintained;
• if it is judged that the predetermined interval or more is not maintained, temporarily placing again the first image of the first side and the second image of the second side;
• and
• if it is judged that the predetermined interval or more is not needed or if it is judged that the predetermined interval or more is maintained, setting the temporary placement positions as placement positions of the first image of the first side and the second image of the second side, are carried out.