Image forming apparatus that detects consumable supplies

1. An image forming apparatus comprising:

an image carrying member;

a developing device that develops an electrostatic latent image on the image carrying member by using a toner;

a controller that switches between a first toner empty stop condition and a second toner empty stop condition are in response to the state of the device, wherein said first toner empty stop condition and said second toner empty stop condition for prohibiting printing because of a lack of the remaining amount in the toner are provided;

a toner cartridge that contains toner and is replaceably fitted to a body of the image forming apparatus;

a sub hopper that is placed between said toner cartridge and said developing device to deliver the toner of said toner cartridge to said developing device;

a first unit that replenishes the toner from said toner cartridge to said sub hopper;

a second unit that replenishes the toner from said sub hopper to said developing device;

a sub hopper remaining amount detection unit that detects a toner remaining amount in said sub hopper; and

a toner concentration detection unit that detects the toner concentration in said developing device;

wherein:

said first toner empty stop condition is judged by said sub hopper remaining amount detection unit depending on the fact that said sub hopper is vacant; and

said second toner empty stop condition is judged by said toner concentration detection unit after said sub hopper is vacant depending on the fact that the toner concentration in said developing device is not more than a predetermined value.

2. An image forming apparatus comprising:

an image carrying member;

a developing device that develops an electrostatic latent image on the image carrying member by using a toner;

a controller that switches between a first toner empty stop condition and a second toner empty stop condition are in response to the state of the device, wherein said first toner empty stop condition and said second toner empty stop condition for prohibiting printing because of a lack of the remaining amount in the toner are provided;

the state of the device when switching the toner empty stop condition between said first toner empty stop condition and said second toner empty stop condition is a color of the toner of a toner cartridge that contains toner and is replaceably fitted to a body of the image forming apparatus; and wherein

in the case of the toners of colors of Y, M, and C, the empty stop is judged under said first toner empty stop condition; and

in the case of the toner of a color of K, the empty stop is judged under said second toner empty stop condition.

3. An image forming apparatus comprising:

an image carrying member;

a developing device that develops an electrostatic latent image on the image carrying member by using a toner;

a controller that switches between a first toner empty stop condition and a second toner empty stop condition are in response to the state of the device, wherein said first toner empty stop condition and said second toner empty stop condition for prohibiting printing because of a lack of the remaining amount in the toner are provided;

the state of the device when switching the toner empty stop condition between said first toner empty stop condition and said second toner empty stop condition is a life of said developing device; and wherein

in the case that the life of said developing device is in the initial stage, the empty stop is judged under said second toner empty stop condition; and

in the case that the life of said developing device is in the end stage, the empty stop is judged under said first toner empty stop condition.

4. An image forming apparatus comprising:

an image carrying member;

a developing device that develops an electrostatic latent image on the image carrying member by using a toner;

a controller that switches between a first toner empty stop condition and a second toner empty stop condition are in response to the state of the device, wherein said first toner empty stop condition and said second toner empty stop condition for prohibiting printing because of a lack of the remaining amount in the toner are provided;

the state of the device when switching the toner empty stop condition between said first toner empty stop condition and said second toner empty stop condition is a charged voltage Vg of said image carrying member or a developing bias voltage Vdc; and wherein

in the case that said charged voltage Vg or said developing bias voltage Vdc is larger than a predetermined value, under said first toner empty stop condition, the empty stop is judged; and

in the case that said charged voltage Vg or said developing bias voltage Vdc is smaller than a predetermined value, under said second toner empty stop condition, the empty stop is judged.

5. An image forming apparatus comprising:

an image carrying member;

a developing device that develops an electrostatic latent image on the image carrying member by using a toner;

a controller that switches between a first toner empty stop condition and a second toner empty stop condition are in response to the state of the device, wherein said first toner empty stop condition and said second toner empty stop condition for prohibiting printing because of a lack of the remaining amount in the toner are provided;

the state of the device when switching the toner empty stop condition between said first toner empty stop condition and said second toner empty stop condition is genuineness and non-genuineness of a toner cartridge that contains toner and is replaceably fitted to a body of the image forming apparatus; and wherein

in the case that said toner cartridge is a genuine one, under said second toner empty stop condition, the empty stop is judged; and

in the case that said toner cartridge is a non-genuine one, under said first toner empty stop condition, the empty stop is judged.