Abstract: There is a need to improve estimation accuracy of a failure estimation method or its failure estimation apparatus that performs failure estimation on a targeted instrument based on history information about several instruments mounted with the same type of semiconductor device as an instrument targeted at failure estimation. A failure estimation apparatus that includes a history information database storing history information about a plurality of instruments mounted with the same type of semiconductor device and performs failure estimation on a targeted instrument mounted with a semiconductor device whose type equals the type, wherein the history information contains operation information and failure information; wherein the operation information indicates a chronological operating state of the semiconductor device mounted on the instruments; wherein the failure information indicates a failure cause of a failed instrument; and wherein the operating state is categorized into a plurality of classifications.

Abstract: There is a need to improve estimation accuracy of a failure estimation method or its failure estimation apparatus that performs failure estimation on a targeted instrument based on history information about several instruments mounted with the same type of semiconductor device as an instrument targeted at failure estimation. A failure estimation apparatus that includes a history information database storing history information about a plurality of instruments mounted with the same type of semiconductor device and performs failure estimation on a targeted instrument mounted with a semiconductor device whose type equals the type, wherein the history information contains operation information and failure information; wherein the operation information indicates a chronological operating state of the semiconductor device mounted on the instruments; wherein the failure information indicates a failure cause of a failed instrument; and wherein the operating state is categorized into a plurality of classifications.

Abstract: ElectrophotographLc image formation by an LED array consisting of a plurality of LED chips arranged in a row and a driver having a plurality of drive ICs each connected in parallel to each of m units of LED array chips within each of n groups obtained by partition of the entire LED array. To execute a scanning of the LED array chip emitting in response to drive signals from said drive IC by scanning means to provide repetitious m-divisional scans for each n-partitioned group of chips simultaneously, a control device controls each drive IC, upon leaving a scan in a finest group of chips, to start scanning LED array chips in an adjacent succeeding group with respect to the scanning direction, while another drive IC starts scanning in the first group of chips, the array and the driver thereby scanning in waves to achieve faster printing speed with reduced electronic consumption.