Method for calculating the output characteristic of an optical tip array and image forming apparatus

An optical write device which individually drives a plurality of optical elements arranged in a main scanning direction, in accordance with data about three primary colors to expose a recording medium with light signals of three different colors to form a color image thereon, each of said plurality of optical elements being capable of outputting the light signals of the three different colors, the device comprising:

• a light-quantity measuring device having a photosensor for measuring a quantity of each of the three different colors of light outputted from each of the optical elements;
• and
• an adjusting unit which makes up a difference in spectral sensitivity characteristic between the photosensor and the recording medium, wherein
• said adjusting unit alternates an exposure condition between a first condition and a second condition, the first condition being for measuring the quantity of light outputted from each of the optical elements by said photosensor, the second condition being for exposing the recording medium by the optical elements.

An image forming apparatus capable of forming an image having at most p tone levels, p being a natural number, said image forming apparatus comprising:

• at least one light signal emitter;
• a driver which is connected to said light signal emitter so as to drive said light signal emitter in accordance with driving image data;
• a light-quantity detector which detects quantities of light emitted from the light signal emitter, the light-quantity detector separately detecting a plurality of quantities of light emitted from the light signal emitter which is driven for reproduction of q tone levels, q being a natural number larger than 2 but smaller than p;
• and
• a controller comprising:
• a first control section which calculates an output characteristic of the light signal emitter based on the quantities of light of the q tone levels detected by the light-quantity detector and which stores the output characteristic in a memory;
• and
• a second control section which inputs image data and generates the driving image data based on the inputted image data and the output characteristic stored in the memory.

An image forming apparatus capable of forming an image having at most p tone levels, p being a natural number, said image forming apparatus comprising:

• at least one light signal emitter;
• a driver which is connected to said light signal emitter so as to drive said light signal emitter in accordance with driving image data;
• a memory which stores an output characteristic of the light signal emitter which is calculated based on a plurality of quantities of light separately emitted from the light signal emitter for reproduction of q tone levels, q being a natural number larger than 2 but smaller than p;
• and
• a controller which inputs image data and generates the driving image data based on the inputted image data and the output characteristic stored in the memory.

An apparatus for determining an output characteristic of an optical write device which drives a plurality of optical elements arranged in a main scanning direction individually in accordance with image data, the apparatus comprising:

• a driver which drives the plurality optical elements for providing at least three different tone levels;
• a measuring device which measures quantities of light outputted from each of the optical elements at each of the tone levels;
• and
• a processor which calculates an expression which indicates an output characteristic of each of the optical elements from measured values.