CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2019-205798 filed Nov. 13, 2019. The entire content of the priority application is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an image forming apparatus.

BACKGROUND

There has conventionally been known an image forming apparatus including a process cartridge including a photosensitive drum and a developing roller, and a toner cartridge accommodating therein toner. The toner cartridge is attachable to and detachable from the process cartridge. In a state where the toner cartridge is attached to the process cartridge, the toner accommodated in the toner cartridge is supplied to the process cartridge through a toner supply opening of the toner cartridge.

Such type of an image Bunning apparatus includes, for example, a housing for accommodating therein the process cartridge and the toner cartridge, and a top cover for opening and closing an opening of the housing. The replacement of the toner cartridge with a new toner cartridge is performed in a state where the top cover is open. The image forming apparatus further includes a shutter for opening and closing the toner supply opening so as to prevent toner from being scattered out of the toner supply opening when the toner cartridge is detached from the process cartridge. The image forming apparatus further includes a mechanism that closes the shutter of the toner supply opening in interlocking relation to opening motion of the top cover (for example, see Japanese Patent Application Publication No. 2014-044323).

Further, there has also been known an image forming apparatus including a top cover pivotally movable about an pivot axis for opening and closing an opening of a housing, a drum cartridge including a photosensitive drum, a developing cartridge attachable to and detachable from the drum cartridge and including a developing roller and a toner accommodation portion, and an LED head configured to expose the photosensitive drum to light.

Such type of an image forming apparatus includes a mechanism that tilts the developing cartridge in a direction away from the pivot axis of the top cover in interlocking relation to opening motion of the top cover (for example, see Japanese Patent Application Publication No. 2018-055067).

SUMMARY

There has been known a conventional image forming apparatus including a process unit that performs an image formation by supplying toner to a photosensitive drum that has been exposed to light by an LED head. In this type of an image forming apparatus, in view of minimization in replacement cost of cartridges, it is desirable that the process unit is constituted by two cartridges, i.e., a process cartridge having a long service life and a toner cartridge having a short service life, and that the replacement of the toner cartridge can be easily performed in a state where the process cartridge is attached to the housing.

However, the above-described desired structure in which the replacement of the toner cartridge can be easily performed with the process cartridge attached to the housing is difficult to achieve by just combining the technology described in the JP publication No. 2014-044323 in which the shutter of the toner supply opening is closed in interlocking relation to opening motion of the top cover, and the technology described in the JP publication No. 2018-055067 in which the developing cartridge is moved to be tilted in the direction away from the pivot axis of the top cover in interlocking with opening motion of the top cover.

In view of the foregoing, it is an object of the present disclosure to provide an image forming apparatus in which the replacement of the toner cartridge can be easily performed with the process cartridge attached to the housing in a case where the process unit is constituted by two cartridges, i.e., the process cartridge including the photosensitive drum and the developing roller, and the toner cartridge accommodating therein toner.

In order to attain the above and other objects, according to one aspect, the present disclosure provides an image forming apparatus including: a housing, a top cover, a process cartridge, a toner cartridge, and an interlocking mechanism. The housing has an opening. The top cover is pivotally movable about a first pivot axis between a first position where the top cover closes the opening and a second position where the top cover opens the opening. The process cartridge attachable to and detachable from the housing. The process cartridge includes: a developing roller, a photosensitive drum; and a support portion. The toner cartridge attachable to and detachable from the process cartridge. The toner cartridge includes: a toner accommodating portion configured to accommodate therein toner, and a connecting portion connectable to the process cartridge. The interlocking mechanism is configured to move the toner cartridge in interlocking with movement of the top cover. In a state where the toner cartridge is attached to the process cartridge, the toner cartridge is pivotally movable about a second pivot axis between: an attachment/detachment position where the toner cartridge is attachable to and detachable from the process cartridge, and a fixed position where the toner cartridge is fixed to the process cartridge. The second pivot axis extends in parallel to a rotation axis of the photosensitive drum. In a state where the process cartridge having the toner cartridge attached thereto is attached to the housing and the top cover is at the first position, the toner cartridge is supported by the support portion so as to have such a posture that the toner accommodating portion is positioned closer to the top cover than the connecting portion is to the top cover and the connecting portion is positioned closer to the support portion than the toner accommodating portion is to the support portion. The interlocking mechanism is configured to: pivotally move the toner cartridge from the fixed position to the attachment/detachment position when the top cover is moved from the first position to the second position; and pivotally move the toner cartridge from the attachment/detachment position to the fixed position when the top cover is moved from the second position to the first position.

According to another aspect, the present disclosure provides an image forming apparatus includes: a housing, a top cover, a first process cartridge, a second process cartridge, a first toner cartridge, a second toner cartridge, and an interlocking mechanism. The housing has an opening. The top cover is pivotally movable about a first pivot axis between a first position where the top cover closes the opening and a second position where the top cover opens the opening. The first process cartridge is attachable to and detachable from the housing. The first process cartridge comprising: a first developing roller, a first photosensitive drum, and a first support portion. The second process cartridge is attachable to and detachable from the housing. The second process cartridge includes: a second developing roller, a second photosensitive drum, and a second support portion. The first toner cartridge is attachable to and detachable from the first process cartridge. The first toner cartridge includes: a first toner accommodating portion configured to accommodate therein first toner, and a first connecting portion connectable to the first process cartridge. The second toner cartridge is attachable to and detachable from the second process cartridge. The second toner cartridge includes: a second toner accommodating portion configured to accommodate therein second toner, and a second connecting portion connectable to the second process cartridge. The interlocking mechanism is configured to move the first toner cartridge and the second toner cartridge in interlocking with movement of the top cover. In a state where the first toner cartridge is attached to the first process cartridge, the first toner cartridge is pivotally movable about a second pivot axis between: a first attachment/detachment position where the first toner cartridge is attachable to and detachable from the first process cartridge, and a first fixed position where the first toner cartridge is fixed to the first process cartridge. The second pivot axis extends in parallel to a first rotation axis of the first photosensitive drum. In a state where the second toner cartridge is attached to the second process cartridge, the second toner cartridge is pivotally movable about a third pivot axis between: a second attachment/detachment position where the second toner cartridge is attachable to and detachable from the second process cartridge, and a second fixed position where the second toner cartridge is fixed to the second process cartridge. The third pivot axis extends in parallel to a second rotation axis of the second photosensitive drum. In a state where the first process cartridge having the first toner cartridge attached thereto is attached to the housing and the top cover is at the first position, the first toner cartridge is supported by the first support portion so as to have such a posture that the first toner accommodating portion is positioned closer to the top cover than the first connecting portion is to the top cover and the first connecting portion is positioned closer to the first support portion than the first toner accommodating portion is to the first support portion. In a state where the second process cartridge having the second toner cartridge attached thereto is attached to the housing and the top cover is at the first position, the second toner cartridge is supported by the second support portion so as to have such a posture that the second toner accommodating portion is positioned closer to the top cover than the second connecting portion is to the top cover and the second connecting portion is positioned closer to the second support portion than the second toner accommodating portion is to the second support portion. The interlocking mechanism is configured to: when the top cover is moved from the first position to the second position, pivotally move the first toner cartridge from the first fixed position to the first attachment/detachment position; and pivotally move the second toner cartridge from the second fixed position to the second attachment/detachment position; and when the top cover is moved from the second position to the open position, pivotally move the first toner cartridge from the first attachment/detachment position to the first fixed position; and pivotally move the second toner cartridge from the second attachment/detachment position to the second fixed position.

