| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus which is allowed to use a consumable drum unit till the expiration of its life without wasting the unit.SOLUTION: Two developing units of a developing unit 12a with a regular width, which is used for printing on A4 size sheet in lateral form, and a spare developing unit 12b with a short width, which is used for printing on A4 size sheet in vertical form, are prepared for enabling satisfactory printing in a central portion with the width of 200 mm or less even after a photoreceptor drum reaches its life in regular use. When the photoreceptor drum reaches its life in regular use, a user is made to select a printing method while displaying the following messages: the drum unit has reached its life; the drum unit must be replaced with a new one if printing is carried out on A4 size paper in lateral form or A3 size paper; if A4 size paper in vertical form is used, additional printings are possible on an approximately X number of sheets without replacing the drum unit. |
