Developer, developer cartridge, developing unit, and image forming apparatus

Abstract

A developer contains a resin, a coloring agent, and an external additive in an amount of 2.5 to 4.5 weight parts added to the resin in an amount of 100 weight parts resin. The developer has an average volume mean particle diameter in the range of 4.5 to 6.5 μm and a BET specific surface in the range of 2.45 to 3.74 m2/g. The external additive may be silica.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limiting the present invention, and wherein:

FIG. 1A illustrates toner having a relatively large BET specific surface;

FIG. 1B illustrates toner having a relatively small BET specific surface;

FIG. 2 is a cross-sectional side view illustrating the configuration of an image forming apparatus;

FIG. 3 illustrates an image forming section;

FIG. 4 is an expanded view illustrating a pertinent portion of the image forming section;

FIG. 5 illustrates a pertinent portion of a toner cartridge;

FIG. 6 is a cross-sectional side view of a fixing unit; and

FIG. 7 illustrates how a line pressure applied by the cleaning blade on the photoconductive drum is calculated.

Claims

1. A developers comprising: a resin;a coloring agent;an external additive in an amount of 2.5 to 4.5 weight parts added to the resin in an amount of 100 weight parts resin; andwherein the developer has an average volume mean particle diameter in the range of 4.5 to 6.5 μm and a BET specific surface in the range of 2.45 to 3.74 m2/g.

2. The developer according to claim 1, wherein the external additive is silica.

3. A developer cartridge that holds the developer of claim 1.

4. An image forming mechanism comprising: a chamber that holds developer;an image bearing body including a surface that runs at a linear speed in the range of 50-300 mm/s;a charging member that charges a surface of said image bearing body;an exposing member that illuminates the charged surface of said image bearing body to form an electrostatic latent image on said image bearing body; anda developer bearing body that supplies the developer to the electrostatic latent image to develop the electrostatic latent image into a visible image;a resilient member disposed upstream of said charging member with respect to rotation of said image bearing body and downstream of said developer bearing body, said resilient member being in resilient contact with said image bearing body such that said resilient member exerts a line pressure in the range of 0.8-2.4 gf/mm on said image bearing body.

5. The image forming mechanism according to claim 4, wherein the developer includes: a resin,a coloring agent, andan external additive in an amount of 2.5 to 4.5 weight parts added to the resin in an amount of 100 weight parts resin,wherein the developer has an average volume mean particle diameter in the range of 4.5 to 6.5 μm and a BET specific surface in the range of 2.45 to 3.74 m2/g.

6. The image forming mechanism according to claim 4, wherein the developer has an average roundness in the range of 0.900-0.940.

7. An image forming apparatus that incorporates the image forming mechanism of claim 4, wherein the image forming apparatus comprises: a transfer section that transfers the visible image onto a recording medium; anda fixing section that fixes the visible image into a permanent image.