An image processing unit for an image forming apparatus, the image processing unit comprising: a first memory unit configured to store a first setup value which is set for each of one or more groups, each group including at least one user, and said first setup value indicates an upper limit of a usage amount for each at least one user included in each group, within which the at least one user included in each group can use a function; a second memory unit configured to store a second setup value which is set for each of the at least one user and indicates the usage amount of said function attributed to each user of the at least one user to use the function in addition to the first setup value; and a third memory unit configured to store a current value which indicates the usage amount of the function used by each user; the image processing unit further comprising: a determination unit configured to determine whether the current value exceeds a predetermined first threshold determined using the first setup value set for a group, in which each user is included, among the groups and the second setup value set for each user of the at least one user; wherein the predetermined first threshold is a sum of the first setup value and the second setup value or a value obtained by multiplying the sum by a predetermined ratio; when it is determined that the first threshold value is not exceeded, the user is allowed to use the function; and when it is determined that the first threshold value is exceeded, the user is not allowed to use the function. a first memory unit configured to store a first setup value which is set for each of one or more groups, each group including at least one user, and said first setup value indicates an upper limit of a usage amount for each at least one user included in each group, within which the at least one user included in each group can use a function; a second memory unit configured to store a second setup value which is set for each of the at least one user and indicates the usage amount of said function attributed to each user of the at least one user to use the function in addition to the first setup value; and a third memory unit configured to store a current value which indicates the usage amount of the function used by each user; the image processing unit further comprising: a determination unit configured to determine whether the current value exceeds a predetermined first threshold determined using the first setup value set for a group, in which each user is included, among the groups and the second setup value set for each user of the at least one user; wherein the predetermined first threshold is a sum of the first setup value and the second setup value or a value obtained by multiplying the sum by a predetermined ratio; when it is determined that the first threshold value is not exceeded, the user is allowed to use the function; and when it is determined that the first threshold value is exceeded, the user is not allowed to use the function. a determination unit configured to determine whether the current value exceeds a predetermined first threshold determined using the first setup value set for a group, in which each user is included, among the groups and the second setup value set for each user of the at least one user; wherein the predetermined first threshold is a sum of the first setup value and the second setup value or a value obtained by multiplying the sum by a predetermined ratio; when it is determined that the first threshold value is not exceeded, the user is allowed to use the function; and when it is determined that the first threshold value is exceeded, the user is not allowed to use the function.