Image forming apparatus for maintaining a constant beam scanning state

An image forming apparatus capable of switching a color image formation mode and a monochrome image formation mode and storing a control state in each mode, the apparatus comprising:

• a first light beam generator to generate a first light beams;
• a second light beam generator to generate a second light beams;
• a scanner to control the first and the second light beams generated by the first and the second light beam generators, respectively, for scanning;
• a first scanning state changer to change a scanning state of the first light beam;
• a second scanning state changer to change a scanning state of the second light beam;
• a first member to be exposed, scanned with the first light beam or both the first and the second light beams while the first member transferring in a perpendicular direction with respect to a beam scanning direction;
• a second member to be exposed, scanned with the second light beam while the second member transferring in the perpendicular direction with respect to the beam scanning direction;
• a first mode image generator to scan the first member to be exposed with the first and the second light beams, thus-generating a monochrome image in a first image formation mode;
• a second mode image generator to scan the first member to be exposed with the first light beam and scan the second member to be exposed with the second light beam, thus generating a color image in a second image formation mode;
• a first light beam detector to detect a scanning state of the first light beam or the first and the second light beams to the first member to be exposed;
• a second light beam detector to detect a scanning state of the second light beam to the second member to be exposed;
• a selector to select either the first image formation mode or the second image formation mode;
• a first memory to store the scanning state of the first light beam to the first member to be exposed in the first image formation mode;
• a second memory to store the scanning state of the first light beam to the first member to be exposed and the scanning state of the second light beam to the second member to be exposed in the second image formation mode;
• and
• a controller to control the first and the second scanning state changers in accordance with information stored in the first or the second memory when the selector performs selection of image formation mode.

An image forming apparatus capable of switching a color image formation mode and a monochrome image formation mode and outputting a test pattern, the apparatus comprising:

• a first light beam generator to generate a first light beams;
• a second light beam generator to generate a second light beams;
• a scanner to control the first and the second light beams generated by the first and the second light beam generators, respectively, for scanning;
• a first scanning state changer to change a scanning state of the first light beam;
• a second scanning state changer to change a scanning state of the second light beam;
• a first member to be exposed, scanned with the first light beam or both the first and the second light beams while the first member transferring in a perpendicular direction with respect to a beam scanning direction;
• a second member to be exposed, scanned with the second light beam while the second member transferring in the perpendicular direction with respect to the beam scanning direction;
• a first mode image generator to scan the first member to be exposed with the first and the second light beams, thus generating a monochrome image in a first image formation mode;
• a second mode image generator to scan the first member to be exposed with the first light beam and scan the second member to be exposed with the second light beam, thus generating a color image in a second image formation mode;
• a first light beam detector to detect a scanning state of the first light beam or the first and the second light beams to the first member to be exposed;
• a second light beam detector to detect a scanning state of the second light beam to the second member to be exposed;
• a selector to select either the first image formation mode or the second image formation mode;
• a image positional relationship detector to determine whether a position of an image formed by the first light beam and another image formed by the second light beam lie in a predetermined positional relationship in the second image formation mode;
• a memory to store the scanning states of the first and the second light beams when the first and the second scanning state changers are controlled so that the image formed by the first light beam and the other image formed by the second light beam lie in the predetermined positional relationship in the second image formation mode;
• and
• a controller, in the first image formation mode, to detect the scanning states of the first and the second light beams to the first member to be exposed through the first detector, thus controlling the first and the second scanning state changers so that each light beam is set in a certain scanning state, in the second image formation mode, to control the first and the second scanning state changers in accordance with information stored in the memory.

An image forming apparatus capable of switching a color image formation mode and a monochrome image formation mode, outputting a test pattern and storing a control state in each mode, the apparatus comprising:

• a first light beam generator to generate a first light beams;
• a second light beam generator to generate a second light beams;
• a scanner to control the first and the second light beams generated by the first and the second light beam generators, respectively, for scanning;
• a first scanning state changer to change a scanning state of the first light beam;
• a second scanning state changer to change a scanning state of the second light beam;
• a first member to be exposed, scanned with the first light beam or both the first and the second light beams while the first member transferring in a perpendicular direction with respect to a beam scanning direction;
• a second member to be exposed, scanned with the second light beam while the second member transferring in the perpendicular direction with respect to the beam scanning direction;
• a first mode image generator to scan the first member to be exposed with the first and the second light beams, thus generating a monochrome image in a first image formation mode;
• a second mode image generator to scan the first member to be exposed with the first light beam and scan the second member to be exposed with the second light beam, thus generating a color image in a second image formation mode;
• a first light beam detector to detect a scanning state of the first light beam or the first and the second light beams to the first member to be exposed;
• a second light beam detector to detect a scanning state of the second light beam to the second member to be exposed;
• a selector to select either the first image formation mode or the second image formation mode;
• a first memory to store the scanning states of at least the first and the second light beams to the first member to be exposed or control states of the first and the second scanning state changers in the first image formation mode;
• an image positional relationship detector to detect a positional relationship of an image formed by the first light beam and another image formed by the second light beam in the second image formation mode;
• a memory to store the scanning states of the first and the second light beams when the first and the second scanning state changers are controlled so that the image formed by the first light beam and the other image formed by the second light beam lie in the predetermined positional relationship in the second image formation mode;
• and
• a controller, when the selector selects the first image formation mode, to control the first and the second scanning state changers in accordance with information stored in the first memory, whereas when the selector selects the image formation mode, to control the first and the second scanning state changers in accordance with information stored in the second memory.