Image forming apparatus and detachable unit for use therewith

1. An image forming apparatus comprising:

an apparatus main body including a guide section and a contact terminal as a spring; and

a detachable unit including a holder for holding a circuit board having an electrode terminal which comes into contact with the contact terminal, a state of the detachable unit being changed to an attached state by inserting the detachable unit along the guide section in an insertion direction, the state of the detachable unit being changed to a detached state by withdrawing the detachable unit along the guide section in a withdrawal direction opposite to the insertion direction, wherein:

the holder includes a first positioning member for positioning a tip end of the circuit board in the insertion direction when the detachable unit holding the circuit board in the holder is slid along the guide section to be inserted in the insertion direction; and

the first positioning member forms two slit parts, through which the contact terminal passes when the detachable unit not holding the circuit board in the holder in the attached state is slid in the withdrawal direction.

2. The image forming apparatus of claim 1 , wherein:

the holder includes a second positioning member which positions a rear end of the circuit board in the insertion direction, the rear end being opposite to the tip end; and

a recess formed between the first positioning member and the second positioning member; and

at least a part of the contact terminal is located in the recess when the detachable unit not holding the circuit board in the holder is in the attached state.

3. The image forming apparatus of claim 1 , wherein the contact terminal is in contact with the electrode terminal when the detachable unit holding the circuit board in the holder is in the attached state.

4. The image forming apparatus of claim 1 , wherein the electrode terminal is a tabular electrode parallel to the insertion direction.

5. The image forming apparatus of claim 1 , wherein:

the contact terminal changes from an initial state, in which no load is applied to the contact terminal, to a contact state, in which the contact terminal is pushed down by the circuit board, when the detachable unit holding the circuit board in the holder is inserted into the apparatus main body; and

the contact terminal returns from the contact state to the initial state when the detachable unit holding the circuit board in the holder is withdrawn from the apparatus main body.

6. The image forming apparatus of claim 1 , wherein the contact terminal includes:

a fixed end fixed to the apparatus main body, the fixed end being formed on a rear end side in the insertion direction;

a free end formed on a tip end side opposite to the rear end side in the insertion direction; and

an apex part formed between the fixed end and the free end, the apex part being formed by bending a plate member into L-shape.

7. The image forming apparatus of claim 1 , wherein the detachable unit is a developer cartridge containing a developer.

8. The image forming apparatus of claim 1 , wherein the detachable unit is an image forming unit including an image carrier on which an electrostatic latent image is formed.

9. The image forming apparatus of claim 1 , wherein the detachable unit is a fixing unit which fixes a developer image onto a recording medium.

10. The image forming apparatus of claim 1 , wherein:

the holder includes a second positioning member which positions a rear end of the circuit board in the insertion direction, the rear end being opposite to the tip end;

a recess is formed between the first positioning member and the second positioning member; and

bottom faces of the slit parts and the recess are on a same level in height.

11. A detachable unit configured to be inserted into and to be withdrawn from an image forming apparatus that includes a guide section and a contact terminal as a spring, a state of the detachable unit being changed to an attached state by inserting the detachable unit along the guide section in an insertion direction, the state of the detachable unit being changed to a detached state by withdrawing the detachable unit along the guide section in a withdrawal direction opposite to the insertion direction, the detachable unit comprising:

a unit main body; and

a holder provided on the unit main body, the holder being configured to hold a circuit board including an electrode terminal which comes into contact with the contact terminal, wherein

the holder includes a first positioning member for positioning a tip end of the circuit board in the insertion direction when the detachable unit holding the circuit board in the holder is slid along the guide section to be inserted in the insertion direction; and

the first positioning member forms two slit parts through which the contact terminal passes when the detachable unit not holding the circuit board in the holder in the attached state is slid in the withdrawal direction.

12. The detachable unit of claim 11 , wherein the holder includes a second positioning member which positions a rear end of the circuit board in the insertion direction, the rear end being opposite to the tip end; and

a recess formed between the first positioning member and the second positioning member; and

at least a part of the contact terminal is located in the recess when the detachable unit not holding the circuit board in the holder is in the attached state.

13. The detachable unit of claim 11 , wherein the electrode terminal is a tabular electrode parallel to the insertion direction.

14. The detachable unit of claim 11 , wherein

the holder includes a second positioning member which positions a rear end of the circuit board in the insertion direction, the rear end being opposite to the tip end;

a recess is formed between the first positioning member and the second positioning member; and

bottom faces of the slit parts and the recess are on the same level in height.

15. An image forming apparatus comprising:

an apparatus main body including a guide section and a contact terminal as a spring;

a detachable unit including a holder for holding a circuit board having an electrode terminal which comes into contact with the contact terminal, a state of the detachable unit being changed to an attached state by inserting the detachable unit along the guide section in an insertion direction, the state of the detachable unit being changed to a detached state by withdrawing the detachable unit along the guide section in a withdrawal direction opposite to the insertion direction;

a base plate including a first face and a second face opposite to the first face, the base plate supporting the contact terminal on the first face;

a signal cable connected to the contact terminal; and

a cable guide, along which the signal cable extends from the first face to the second face, wherein:

the holder includes a first positioning member for positioning a tip end of the circuit board in the insertion direction when the detachable unit holding the circuit board in the holder is slid along the guide section to be inserted in the insertion direction; and

the first positioning member forms a slit part through which the contact terminal passes when the detachable unit not holding the circuit board in the holder in the attached state is slid in the withdrawal direction.

16. The image forming apparatus of claim 15 , wherein the base plate includes an L-shaped notch as a part of the cable guide.

17. The image forming apparatus of claim 16 , wherein the base plate includes a hook which prevents the signal cable from coming out of the L-shaped notch.

18. The image forming apparatus of claim 15 , wherein the base plate includes a through hole as a part of the cable guide.

19. The image forming apparatus of claim 15 , wherein:

the base plate further includes an angle connector which electrically connects the contact terminal and the signal cable; and

the angle connector includes a slot configured to be inserted by the signal cable, the slot facing the insertion direction.