Image forming apparatus having detachable process units

1. An image forming apparatus which forms an image, comprising:

a plurality of process units arranged in a predetermined direction to form a process-unit row, each of the process units having a photosensitive body and a developer container;

a casing accommodating the process units, and having an opening which is formed in the casing at one side in the predetermined direction, and a cover which opens and closes the opening; and

an exposure member exposing the photosensitive body, and having a laser source, a deflector which deflects a laser beam emitted from the laser source, and an optical element which focuses the emitted laser beam, the exposure member being arranged to face the developer container of each of the process units in a direction orthogonal to the predetermined direction;

wherein the process units are detachable, with respect to the casing, through the opening of the casing;

wherein the developer container of one process unit, among the process units, arranged at one end of the process-unit row has a protruding portion which protrudes toward the exposure member to overlap with the exposure member in the direction orthogonal to the predetermined direction;

wherein the one process unit arranged at one end of the process-unit row is separable into a photosensitive-body unit having the photosensitive body, and a developer unit having the developer container and developer rollers; and

wherein the developer unit is detachable, through the opening of the casing, in a state of being separated from the photosensitive-body unit.

2. The image forming apparatus according to claim 1 , wherein the developer container of the one process unit arranged at one end of the process-unit row accommodates a developer of black color.

3. The image forming apparatus according to claim 2 , wherein the one process unit arranged at one end of the process-unit row is detachable, from the opening of the casing, with respect to another process unit which is arranged adjacent to the one process unit.

4. The image forming apparatus according to claim 2 , wherein the developer container of the one process unit arranged at one end of the process-unit row has first and second developer containers, the second developer container is formed in a developer cartridge which is separable from the first developer container, and the developer cartridge is detachable, with respect to the first developer container, through the opening of the casing.

5. The image forming apparatus according to claim 2 , further comprising a supporting frame which integrally supports the process units and which is detachable, with respect to the casing, through the opening of the casing.

6. The image forming apparatus according to claim 4 , wherein the developer container of the one process unit arranged at one end of the process-unit row has an opening through which the first and second developer containers communicates with each other, and the opening is closed by a shutter which is provided in the developer container.

7. The image forming apparatus according to claim 4 , wherein the protruding portion of the developer container of the one process unit arranged at one end of the process-unit row is the second developer container.

8. The image forming apparatus according to claim 1 , wherein the one process unit arranged at one end of the process-unit row is closest to the opening of the casing among the process units.

9. The image forming apparatus according to claim 5 , wherein the process units are detachable with respect to the supporting frame respectively.

10. An image forming apparatus which forms an image, comprising:

a plurality of process units arranged in a predetermined direction to form a process-unit row, each of the process units having a photosensitive body and a developer container;

a casing accommodating the process units, and having an opening which is formed in the casing at one side in the predetermined direction, and a cover which opens and closes the opening; and

an exposure member exposing the photosensitive body, and having a laser source, a deflector which deflects a laser beam emitted from the laser source, and an optical element which focuses the emitted laser beam, the exposure member being arranged to face the developer container of each of the process units in a direction orthogonal to the predetermined direction;

wherein the process units are detachable, with respect to the casing, through the opening of the casing;

wherein the developer container of one process unit, among the process units, arranged at one end of the process-unit row has a protruding portion which protrudes toward the exposure member to overlap with the exposure member in the direction orthogonal to the predetermined direction;

wherein the one process unit arranged at one end of the process-unit row is separable into a photosensitive-body unit having the photosensitive body, and a developer unit having the developer container and developer rollers

wherein the developer unit is detachable, through the opening of the casing, in a state of being separated from the photosensitive-body unit;

wherein the developer container of the one process unit arranged at one end of the process-unit row has first and second developer containers, the second developer container is formed in a developer cartridge which is separable from the first developer container, and the developer cartridge is detachable, with respect to the first developer container, through the opening of the casing; and

wherein the developer container of the one process unit arranged at one end of the process-unit row has an opening through which the first and second developer containers communicates with each other, and the opening is closed by a shutter which is provided in the developer container.

11. An image forming apparatus which forms an image, comprising:

a plurality of process units arranged in a predetermined direction to form a process-unit row, each of the process units having a photosensitive body and a developer container;

a casing accommodating the process units, and having an opening which is formed in the casing at one side in the predetermined direction, and a cover which opens and closes the opening; and

an exposure member exposing the photosensitive body, and having a laser source, a deflector which deflects a laser beam emitted from the laser source, and an optical element which focuses the emitted laser beam, the exposure member being arranged to face the developer container of each of the process units in a direction orthogonal to the predetermined direction;

wherein the process units are detachable, with respect to the casing, through the opening of the casing;

wherein the developer container of one process unit, among the process units, arranged at one end of the process-unit row has a protruding portion which protrudes toward the exposure member to overlap with the exposure member in the direction orthogonal to the predetermined direction;

wherein the one process unit arranged at one end of the process-unit row is separable into a photosensitive-body unit having the photosensitive body, and a developer unit having the developer container and developer rollers

wherein the developer unit is detachable, through the opening of the casing, in a state of being separated from the photosensitive-body unit;

wherein the developer container of the one process unit arranged at one end of the process-unit row has first and second developer containers, the second developer container is formed in a developer cartridge which is separable from the first developer container, and the developer cartridge is detachable, with respect to the first developer container, through the opening of the casing; and

wherein the protruding portion of the developer container of the one process unit arranged at one end of the process-unit row is the second developer container.