Patent ID: 7792471

Claim:
An image forming apparatus comprising: an electrostatic-latent-image carrying body which has a latent-image forming surface formed in parallel with a predetermined main scanning direction and configured such that an electrostatic latent image in the form of an electric potential distribution is formed thereon, and which is configured such that the latent-image forming surface can move along a sub-scanning direction orthogonal to the main scanning direction; and a developer supply apparatus disposed to face the electrostatic-latent-image carrying body, and configured to supply a developer in the form of fine particles onto the latent-image forming surface in a state in which the developer is charged, wherein the developer supply apparatus includes: a developer containing casing which is a box-like member configured to be able to contain the developer therein and which includes an opening portion at a position facing the electrostatic-latent-image carrying body; a plurality of transport electrodes arranged along the sub-scan direction such that their longitudinal direction intersects with the sub-scanning direction, the transport electrodes being capable of transporting the developer in a predetermined developer transport direction when a traveling-wave voltage is applied to the transport electrodes; a flexible insulating substrate on which the transport electrodes are provided along the sub-scanning direction and which is accommodated within the developer containing casing such that a predetermined gap is formed between the insulating substrate and an inner wall surface of the developer containing casing; and a substrate support member within the developer containing casing, the substrate support member including an external surface extending in the main scanning direction, where portions of the external surface past the opening portion arc away from said opening, and supports the insulating substrate wherein the insulating substrate is supported on the external surface, and the transport electrodes face the latent-image forming surface via the opening portion with a predetermined developing gap formed therebetween, wherein the insulating substrate is supported by the substrate support member such that the transport electrodes face a developer transport path formed along the inner wall surface of the developer containing casing, and margin areas of the insulating substrate, which are regions of end portions of the insulating substrate with respect to the sub-scanning direction in which regions the transport electrodes are not formed, are separated from the developer transport path.