Image forming apparatus and image forming method

An image forming method in an image forming apparatus, which includes:

• a conveyance unit configured to convey a recording medium in a sub scanning direction;
• a recording head configured to reciprocatingly scan in a main scanning direction perpendicular to the sub scanning direction, to form an image on the recording medium conveyed by the conveyance unit;
• and
• a reversing unit configured to reverse front and back sides of the recording medium and convey the reversed recording medium to the conveyance unit, wherein
• in a case of performing a double-sided printing, while the conveyance unit reciprocatingly conveys the recording medium, the recording head is configured to form a first image on a first side of the recording medium, and while the conveyance unit conveys and ejects the reversed recording medium, front and back sides of which are reversed by the reversing unit, the recording head is configured to form a second image on a second side of the recording medium,
• the method comprising controlling a first conveyance speed V1 at which the conveyance unit conveys the recording medium upon forming the first image on the first side of the recording medium and a second conveyance speed V2 at which the conveyance unit conveys the reversed recording medium upon forming the second image on the second side of the recording medium to satisfy a relation
• V2≦W/t<V1≦(W/t)×2
• where t is a scanning time required for one reciprocation of the recording head in the main scanning direction, and W is an image formation width of the recording head in the sub scanning direction.