Image forming apparatus with developing unit separable from photosensitive member

An image forming apparatus comprising:

• a photosensitive member;
• a scanning unit including a light source, and configured to scan the photosensitive member with light from the light source and to form an electrostatic latent image;
• a developing unit configured to develop the electrostatic latent image to a developer image by contacting with the photosensitive member;
• a driving unit configured to drive the developing unit and to cause the developing unit to come into contact with the photosensitive member or to be separated from the photosensitive member;
• and
• a control unit configured to let the scanning unit perform a preparation operation for the scanning unit to form the electrostatic latent image based on image data, and to control, before the preparation operation of the scanning unit is completed, the driving unit for a predetermined preceding control time period so as to move the developing unit separated from the photosensitive member toward the photosensitive member to an extent in which the developing unit and the photosensitive member are not brought into contact with each other,
• wherein the control unit is further configured to determine the preceding control time period by starting, before the preparation operation of the scanning unit is completed, controlling the driving unit to bring the developing unit into contact with the photosensitive member, forming the electrostatic latent image on the photosensitive member before the developing unit is brought into contact with the photosensitive member, forming the developer image on the photosensitive member by developing the electrostatic latent image formed on the photosensitive member by the developing unit contacted with the photosensitive member, and measuring a time period until the developer image formed on the photosensitive member reaches a predetermined position.

An image forming apparatus comprising:

• a photosensitive member;
• a scanning unit including a light source, and configured to scan the photosensitive member with light from the light source and to form an electrostatic latent image;
• a developing unit configured to develop the electrostatic latent image by contacting with the photosensitive member;
• a driving unit configured to drive the developing unit and to cause the developing unit to come into contact with the photosensitive member or to be separated from the photosensitive member;
• and
• a control unit configured to let the scanning unit perform a preparation operation for the scanning unit to form the electrostatic latent image based on image data, and to control, before the preparation operation of the scanning unit is completed, the driving unit for a predetermined preceding control time period so as to move the developing unit toward the photosensitive member to an extent in which the developing unit and the photosensitive member are not brought into contact with each other,
• wherein the developing unit is configured to be driven to rotate at a predetermined position before being brought into contact with the photosensitive member, and
• the control unit is further configured to determine the preceding control time period by detecting when the developing unit is driven to rotate.