Image forming device

An image forming device, comprising:

• an image holding member;
• means for charging a surface of the image holding member by making contact therewith;
• means for forming an electrostatic latent image by exposing the surface of the image holding member charged by the charging means according to image information;
• means for developing the electrostatic latent image via a spherical toner so as to provide a toner image;
• and
• means for electrostatically transferring the toner image from the surface of the image holding member to a transfer material;
• wherein a toner shape change ratio (Tt) of deformed toner particles passed between the contacting portions of the image holding member and the charging means, represented by the following formula (1), is within a range of 50 to 100 percent,
• Tt(%)=(h/x)×100 Formula (1)
• and in the formula (1), x denotes a maximum length (μm) of a deformed toner particle projected image, h denotes a maximum length (μm) of the deformed toner particle projected image formed on a surface perpendicular to an axis in the maximum length direction of the deformed toner particle projected image, and x≧h.