A reservoir for an inkjet printer, comprising: a 1st compartment (10), comprising at least one 1st part (101) called the upper part, and a 2nd part (102) called the lower part delimited by a convergent shaped wall (14), and a 2nd compartment (20) delimited by a lateral wall, the 2nd part of the 1st compartment (10) being placed in the 2nd compartment (20), the wall (22) of which surrounds it radially, when these 2 compartments are assembled to each other, 1st drawing off means (26) to connect the inside with the outside of the 1st compartment (10), and 2nd drawing off means (28) to connect the inside with the outside of the 2nd compartment (20); a cover (40) to close the 1st compartment (10).