Patent ID: 7231164

Claim:
An electrophotographic image forming apparatus to which a plurality of process cartridges are detachably mountable, said apparatus comprising: (i) a driving source; (ii) mounting means for demountably mounting process cartridges, the process cartridges each including a developing member configured and positioned to develop an electrostatic latent image formed on an electrophotographic photosensitive member, a developer accommodating portion configured to accommodate a developer to be used by the developing member, the developer accommodating portion having a supply opening for supplying the developer to the developing member, a sealing member movable between a sealing position in which the supply opening is sealed and an unsealing position in which the supply opening is unsealed, and a sealing member moving means for moving the sealing member from the sealing position to the unsealing position to unseal the supply opening by receiving a driving force transmitted from said driving source; and (iii) a belt member movable to contact the electrophotographic photosensitive members of all of said process cartridges; and (iv) control means for transmitting the driving force to the sealing member moving means of only the process cartridge for which the sealing position of the sealing member is detected to move the sealing member from the sealing position to the unsealing position, when the plurality of process cartridges are mounted to said apparatus, wherein when said control means detects that sealing members of a plurality of the process cartridges are at the sealing position upon mounting of the plurality of process cartridges to said apparatus, said control means starts unsealing movements of the sealing members with time lags by transmitting the driving forces to the sealing member moving means with time lags.