A cartridge for an ink-jet printer comprising: a cartridge body; a first detecting member protruding from said cartridge body; said first detecting member being suitably designed for interacting with a first sensor of said ink-jet printer for detecting, if said cartridge is installed in said ink-jet printer; a second detecting member for detecting running out of ink, said second detecting member including a shaft fixed on said cartridge body and a lever pivotable around said shaft; said lever being suitably designed for interacting with a second sensor of said ink-jet printer; said cartridge body including an ink storage chamber; characterized in that said cartridge further comprises: a protective cover movable relative to said cartridge body; said ink-jet printer, said protective cover and said cartridge body being designed that said protective cover is moved towards said cartridge body during a process of installing said cartridge in said ink-jet printer; a soft support cap set on said cartridge body and connecting to said ink storage chamber, and a position adjustment member set on said protective cover; if said cartridge is orientated in its installing position, gravity pivots a lower part of said lever towards said position adjustment member and said soft support cap; if said cartridge is orientated in its installing position outside the ink-jet printer, said lever is supported by said position adjustment member; said if said protective cover is in a position closest to said cartridge body and said cartridge is orientated in its installing position, said position adjustment member is above said soft support cap and said soft support cap supports said lever. a cartridge body; a first detecting member protruding from said cartridge body; said first detecting member being suitably designed for interacting with a first sensor of said ink-jet printer for detecting, if said cartridge is installed in said ink-jet printer; a second detecting member for detecting running out of ink, said second detecting member including a shaft fixed on said cartridge body and a lever pivotable around said shaft; said lever being suitably designed for interacting with a second sensor of said ink-jet printer; said cartridge body including an ink storage chamber; characterized in that said cartridge further comprises: a protective cover movable relative to said cartridge body; said ink-jet printer, said protective cover and said cartridge body being designed that said protective cover is moved towards said cartridge body during a process of installing said cartridge in said ink-jet printer; a soft support cap set on said cartridge body and connecting to said ink storage chamber, and a position adjustment member set on said protective cover; if said cartridge is orientated in its installing position, gravity pivots a lower part of said lever towards said position adjustment member and said soft support cap; if said cartridge is orientated in its installing position outside the ink-jet printer, said lever is supported by said position adjustment member; said if said protective cover is in a position closest to said cartridge body and said cartridge is orientated in its installing position, said position adjustment member is above said soft support cap and said soft support cap supports said lever. a protective cover movable relative to said cartridge body; said ink-jet printer, said protective cover and said cartridge body being designed that said protective cover is moved towards said cartridge body during a process of installing said cartridge in said ink-jet printer; a soft support cap set on said cartridge body and connecting to said ink storage chamber, and a position adjustment member set on said protective cover; if said cartridge is orientated in its installing position, gravity pivots a lower part of said lever towards said position adjustment member and said soft support cap; if said cartridge is orientated in its installing position outside the ink-jet printer, said lever is supported by said position adjustment member; said if said protective cover is in a position closest to said cartridge body and said cartridge is orientated in its installing position, said position adjustment member is above said soft support cap and said soft support cap supports said lever.