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US 8,798,487 B2Granted
Image forming apparatus
AssigneeRicoh Company, Ltd.
InventorsTomoharu Asano, Takaaki Ikegami, Michio Kimura
Life of this patent
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AssigneeRicoh Company, Ltd.
InventorsTomoharu Asano, Takaaki Ikegami, Michio Kimura
Estimating the term…
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.
An image forming apparatus comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
By measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor: the characteristics…
Self-diagnostics; Malfunction or lifetime display: monitoring or warning means for exhaustion or lifetime end of consumables, e.g. indication of…
Means for handling parts of the apparatus in the apparatus: for the photosensitive element
Electrography
About 5 years 11 months of term left · ends 5 Oct 2032 (estimated)
This patent application is based on and claims priority pursuant to 35 U.S.C. §119 to Japanese Patent Application No. 2011-006893, filed on Jan. 17, 2011 in the Japanese Patent Office, the entire disclosure of which is hereby incorporated by reference herein.
1. Field of the Invention
The present invention relates to an image forming apparatus.
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the detailed description when considered in connection with the accompanying drawings in which like reference characters designate like corresponding parts throughout and wherein:
FIG. 1 is a schematic diagram illustrating the entire structure of the image forming apparatus related to a first embodiment described later;
FIG. 2 is a graph illustrating the locus of the post-charging surface voltages at the surface portion of an initial (i.e., unused and fresh) image bearing member and an image bearing member producing residual images while changing the amount of the current flowing on the surface portion by changing the bias applied from a transfer device;
Image bearing members have come to the end of its working life when defective images are output beyond a tolerance because of the degradation of the image bearing member caused by abrasion of the surface thereof, the fatigue of the photosensitive layer, etc. There are different kinds of degradation of image quality by which image bearing members are determined as their end of life.
One of them is a residual image reflecting the contrasting density of the previously formed image. In the residual images, there are positive residual images and negative residual images. In the positive residual images, the image density of the (toner attached) portion of the surface of an image bearing member to which toner is attached at the time of forming the previous image is thicker than that of the (toner non-attached) portion of the surface of an image bearing member to which toner is not attached at the time of forming the previous image. In the negative residual image, this image density configuration is reversed.
Both residual images are mainly caused by a transfer current or a transfer voltage applied to the surface of the image bearing member when a toner image on the image bearing member is transferred to a transfer medium (recording medium, intermediate transfer medium, etc.).