Image forming apparatus

1. An image forming apparatus comprising:

a plurality of developing units disposed in parallel with each other, a developer cartridge being detachably attached to each of the plurality of developing units, each of the plurality of developing units forming a developer image with a developer agent in the developer cartridge;

a first cover covering at least one specified developer cartridge of a plurality of developer cartridges attached to the plurality of developing units, the first cover being openable to allow the at least one specified developer cartridge to be attached and detached; and

a second cover covering at least one developer cartridge other than the at least one specified developer cartridge of the plurality of developer cartridges, the second cover being openable to allow the at least one developer cartridge other than the at least one specified developer cartridge to be attached and detached, the second cover including a holding unit for holding each of the plurality of developing units in the closed state of the second cover, the holding unit being a latent image forming unit held by the second cover, the latent image forming unit engaging with each of the plurality of developing units and forming a latent image to be developed by each of the plurality of developing units in the closed state of the second cover;

wherein the first cover includes an information display unit for displaying information;

wherein the first and second covers are configured to be opened in the order of the first cover and the second cover, and to be closed in the order of the second cover and the first cover.

2. The image forming apparatus according to claim 1 , wherein each of the first and second covers uncovers an upper part of the image forming apparatus in the open state.

3. The image forming apparatus according to claim 2 , wherein the first cover has an L-shaped cross section and uncovers the upper part and a side part of the image forming apparatus in the open state.

4. The image forming apparatus according to claim 1 , wherein the first cover uncovers a medium conveying unit for conveying a recording medium for image formation in the open state.

5. The image forming apparatus according to claim 1 , wherein the second cover has a medium discharge portion on which a recording medium after image formation is discharged.

6. The image forming apparatus according to claim 1 , further comprising a control unit for correcting a position error of an image formed by each of the plurality of developing units, when detecting that the second cover is closed, wherein the control unit does not perform the correction of the position error when only the first cover of the first and second covers is opened and closed.

7. The image forming apparatus according to claim 6 , wherein the control unit, when detecting that the second cover is closed, forms a pattern for correction on a transfer medium by each of the plurality of developing units, reads the formed patterns, and corrects the position error based on the result of the reading.

8. The image forming apparatus according to claim 1 , wherein directions in which the plurality of developer cartridges are attached and detached are substantially the same.

9. The image forming apparatus according to claim 1 , wherein when the first and second covers are opened, the whole of an upper part of the plurality of developing units is uncovered.

10. An image forming apparatus comprising:

a plurality of developing units disposed in parallel with each other, a developer cartridge being detachably attached to each of the plurality of developing units, each of the plurality of developing units forming a developer image with a developer agent in the developer cartridge;

a first cover covering at least one specified developer cartridge of a plurality of developer cartridges attached to the plurality of developing units, the first cover being openable to allow the at least one specified developer cartridge to be attached and detached; and

a second cover covering at least one developer cartridge other than the at least one specified developer cartridge of the plurality of developer cartridges, the second cover being openable to allow the at least one developer cartridge other than the at least one specified developer cartridge to be attached and detached, wherein

each of the first and second covers uncovers an upper part of the image forming apparatus in the open state;

the first cover has an L-shaped cross section and uncovers the upper part and a side part of the image forming apparatus in the open state; and

the first cover uncovers a medium conveying unit for conveying a recording medium for image formation in the open state.

11. The image forming apparatus according to claim 10 , wherein directions in which the plurality of developer cartridges are attached and detached are substantially the same.

12. An image forming apparatus comprising:

a plurality of developing units disposed in parallel with each other, a developer cartridge being detachably attached to each of the plurality of developing units, each of the plurality of developing units forming a developer image with a developer agent in the developer cartridge;

a first cover covering at least one specified developer cartridge of a plurality of developer cartridges attached to the plurality of developing units, the first cover being openable to allow the at least one specified developer cartridge to be attached and detached;

a second cover covering at least one developer cartridge other than the at least one specified developer cartridge of the plurality of developer cartridges, the second cover being openable to allow the at least one developer cartridge other than the at least one specified developer cartridge to be attached and detached; and

a control unit for correcting a position error of an image formed by each of the plurality of developing units, when detecting that the second cover is closed, wherein the control unit does not perform the correction of the position error when only the first cover of the first and second covers is opened and closed.

13. The image forming apparatus according to claim 12 , wherein directions in which the plurality of developer cartridges are attached and detached are substantially the same.