An image forming system comprising: an image forming unit configured to form an image by using toner supplied by a toner cartridge; an acquisition unit configured to acquire identification information from the toner cartridge; a first determination unit configured to determine whether or not the toner cartridge satisfies a first condition, based on the identification information; a second determination unit configured to determine whether or not a second condition is satisfied when a determination result of the first determination unit indicates that the toner cartridge does not satisfy the first condition; an authentication information generation unit configured to: generate an authentication information indicating permission instruction to permit the image forming unit to form an image, when the determination result of the first determination unit indicates that the toner cartridge satisfies the first condition, generate an authentication information indicating temporary permission instruction to temporarily permit the image forming unit to form an image, when the determination result of the first determination unit indicates that the toner cartridge does not satisfy the first condition, and generate an authentication information indicating prohibition instruction to prohibit the image forming unit to form an image, when the determination result of the second determination unit indicates that the second condition is satisfied after generating the authentication information indicating temporary permission instruction; an authentication information determination unit configured to acquire the generated authentication information and store state information corresponding to the authentication information in a storage device; a controller configured to control the image forming unit based on the stored state information wherein the first condition is that the cartridge is a genuine product, wherein the second condition is that a predetermined period has elapsed, and wherein the temporary permission instruction is to permit the image forming unit to form an image only for the predetermined period when the determination result of the first determination unit indicates that the toner cartridge does not satisfy the first condition. an image forming unit configured to form an image by using toner supplied by a toner cartridge; an acquisition unit configured to acquire identification information from the toner cartridge; a first determination unit configured to determine whether or not the toner cartridge satisfies a first condition, based on the identification information; a second determination unit configured to determine whether or not a second condition is satisfied when a determination result of the first determination unit indicates that the toner cartridge does not satisfy the first condition; an authentication information generation unit configured to: generate an authentication information indicating permission instruction to permit the image forming unit to form an image, when the determination result of the first determination unit indicates that the toner cartridge satisfies the first condition, generate an authentication information indicating temporary permission instruction to temporarily permit the image forming unit to form an image, when the determination result of the first determination unit indicates that the toner cartridge does not satisfy the first condition, and generate an authentication information indicating prohibition instruction to prohibit the image forming unit to form an image, when the determination result of the second determination unit indicates that the second condition is satisfied after generating the authentication information indicating temporary permission instruction; generate an authentication information indicating permission instruction to permit the image forming unit to form an image, when the determination result of the first determination unit indicates that the toner cartridge satisfies the first condition, generate an authentication information indicating temporary permission instruction to temporarily permit the image forming unit to form an image, when the determination result of the first determination unit indicates that the toner cartridge does not satisfy the first condition, and generate an authentication information indicating prohibition instruction to prohibit the image forming unit to form an image, when the determination result of the second determination unit indicates that the second condition is satisfied after generating the authentication information indicating temporary permission instruction; an authentication information determination unit configured to acquire the generated authentication information and store state information corresponding to the authentication information in a storage device; a controller configured to control the image forming unit based on the stored state information wherein the first condition is that the cartridge is a genuine product, wherein the second condition is that a predetermined period has elapsed, and wherein the temporary permission instruction is to permit the image forming unit to form an image only for the predetermined period when the determination result of the first determination unit indicates that the toner cartridge does not satisfy the first condition.