Image forming apparatus

摘要

An image forming apparatus having an image bearing member, a charger to charge the surface of the image bearing member, an irradiator to irradiate the image bearing member to form the latent image, a developing device to develop the latent electrostatic image with toner to obtain a visible image, a transfer device to transfer the visible image to a transfer medium by a transfer bias applied to a transfer area between the image bearing member and the transfer member, and a voltage detector to measure a first surface voltage and a second surface voltage under different conditions, and a life expectancy identification device to identify whether or when the expected working life of the image bearing member has come to the end based on a comparison of the first surface voltage and the second surface voltage.

主权项

1. An image forming apparatus comprising:
an image bearing member to bear a latent electrostatic image; a charger to charge a surface of the image bearing member; an irradiator to irradiate the image bearing member with light to form the latent image; a developing device to develop the latent electrostatic image with a developing agent comprising toner to obtain a visible image; a transfer device to transfer the visible age to a transfer medium by a transfer bias applied to a transfer area between the image bearing member and the transfer member; a surface voltage detector to measure a first surface voltage of a surface portion of the image bearing member charged by the charger after the image bearing member has passed through the transfer area where the transfer bias is applied by the transfer device to satisfy a first set of current and/or voltage conditions and a second surface voltage of a surface portion of the image bearing member charged by the charger after the image bearing member has passed through the transfer area where the transfer bias is applied by the transfer device to satisfy a second set of current and/or voltage conditions different from the first set of current and/or voltage conditions in absolute value of a current or a voltage applied per unit of area of the surface of the image bearing member; a life expectancy prediction device to predict when the image bearing member comes to the end of its working life based on a comparison of the first surface voltage with the second surface voltage; an over-time information memory device to store information on change over time in the comparison between the first the second surface until the image bearing member has come to the end of its working life, wherein the life expectancy prediction device predicts when the image bearing member comes to the end of its working life from the comparison and from the change over-time information, wherein the life expectancy prediction device:
identifies a reference value corresponding to the surface voltages for use in calculation of the comparison as measured from the change over time information;recalculates the comparison from the first surface voltage and the second surface voltage measured by the surface voltage detector after a predetermined period of time when a difference between the comparison and the reference value is greater than a predetermined value; andpredicts when the image bearing member comes to the end of its working life based on the recalculated comparison.