Abstract: In a toner kit having i) a non-magnetic black toner having at least carbon black and ii) color toners, the black toner has a weight-average particle diameter represented by D4b and a one-point method BET specific surface area represented by Sb, and the color toners, other than the black toner, each have a weight-average particle diameter represented by D4c and a one-point method BET specific surface area represented by Sc, where the black toner and color toners satisfy the following relations (1) and (2):

Abstract: The present invention provides a silica fine particle capable of preventing a charging member or an image bearing member from being contaminated with toner when the toner contains the particle and also capable of providing the toner with a stable developing property. The silica fine particle of the present invention has been hydrophobic treated. Furthermore, the particle has a peak in a range of 0.04 &mgr;m to 1 &mgr;m and a peak in the range of 1 &mgr;m to 100 &mgr;m in a volume-basis particle diameter distribution. The particle has a frequency ratio of 10 to 80% for the particles with a particle diameter of 0.04 &mgr;m to 1 &mgr;m to a total of all the peaks, and the particles has the frequency ratio of less than 16% for the particles with a particle diameters of 20 &mgr;m to 2000 &mgr;m to the total of all the peaks.

Abstract: A discharge exciting excimer laser device comprises a pair of main discharge electrodes, a dielectric and an auxiliary electrode. The dielectric is in a cylindrical form and has a side opposed to one of the main discharge electrodes, which side is formed into a flat plate-like portion. The auxiliary electrode is embraced within the dielectric leaving a space and is opposed to one of the main discharge electrodes with the flat plate-like portion of the dielectric sandwiched therebetween. Such a construction increases laser output and improves insulating performance.