Electrophotography – Diagnostics – Consumable
Reexamination Certificate
2000-09-15
2001-10-09
Chen, Sophia S. (Department: 2852)
Electrophotography
Diagnostics
Consumable
C399S025000, C399S026000
Reexamination Certificate
active
06301450
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrophotography apparatus used as a printer, and more particularly relates to a method for managing the service life of a printing unit replaceably built into an electrophotography apparatus.
2. Description of the Related Art
An electrophotography apparatus is a printing apparatus that performs printing by exposing a photoconductor drum to an image of the printing object, developing the image by toner adhesion, and then transferring and fixing the visibilized image to paper. In the case of color printing, the above steps are carried out for toner of four colors, namely, Y (yellow), M (magenta), C (cyan), and K (black).
The above-mentioned exposure and developing steps are executed by a printing unit replaceably built into the electrophotography apparatus. This printing unit has a photoconductor drum and so forth, and is therefore a consumable part. Accordingly, its service life should be monitored, and when the printing unit reaches the end of this service life, it must be replaced.
In the past, the service life of a printing unit has been managed using service life information such as the number of printed sheets and the operating time, which is stored in a non-volatile memory (such as an EEPROM) of the electrophotography apparatus main unit. Once the number of printed sheets reaches the specified number, or when the operating time reaches the specified time, a replacement indicator is displayed on the control panel of the electrophotography apparatus main unit, recommending to the user that the printing unit be replaced.
However, the following problem is encountered in the conventional management of printing unit service life. When the printing unit is replaced with a used unit that has not reached the end of its service life, rather than a new printing unit, service life management cannot be performed correctly because service life information such as the number of sheets printed and the operating time during the period of usage are unknown.
This problem occurs because the service life information for the printing unit is stored in the electrophotography apparatus main unit. Specifically, if the printing unit itself contained the service life information about the printing unit, then the electrophotography apparatus main unit could perform service life management on the basis of this service life information.
In view of this, a method for managing the service life has been proposed in which a non-volatile memory is installed in the printing unit, the number of printed sheets and other such information is stored therein, and this information is read by the electrophotography apparatus main unit. This allows service life management to be carried out properly even when the printing unit is replaced with a partially used unit.
Unfortunately, the function of a printing unit dictates that high voltage ranging from a few hundred to a few thousand volts be applied during operation. Consequently, there is a problem in that the signal line connecting the non-volatile memory of the printing unit to the electrophotography apparatus main unit may be affected by noise generated by the high-voltage circuit, causing the non-volatile memory to malfunction. For example, the number of printed sheets may be counted erroneously and the wrong number stored in the non-volatile memory.
When a printing unit is replaced, initial operation such as adjusting the printing density is usually carried out so that the printing will correspond to the characteristics of the replacement printing unit. To perform this initial operation, the electrophotography apparatus main unit must be notified that the printing unit has been replaced. This notification is performed by the user, who operates the control panel.
It is entirely possible, however, that the user will forget to perform this operation. If this happens, the printing density will not be adjusted even though the printing unit has been replaced, so there is the danger that the printing will not be sharp and of the appropriate printing density.
SUMMARY OF THE INVENTION
In view of this, it is an object of the present invention to provide an electrophotography apparatus with which the service life management of a printing unit can be carried out properly.
It is another object of the present invention to provide an electrophotography apparatus which can be automatically notified that the printing unit has been replaced, without any user operation.
In order to achieve the stated object, the present invention is constituted by an electrophotography apparatus in which a printing unit is replaceably built into a main unit, wherein this electrophotography apparatus comprises a first non-volatile memory mounted in the main unit, a second non-volatile memory mounted in the printing unit, and a controller for writing a count value, which is updated every specific unit of printing time or every specific number of printed sheets, as a first count value to the first non-volatile memory after every update during print processing, writing the first count value as a second count value to the second non-volatile memory upon completion of the print processing, and evaluating the service life of the printing unit on the basis of the first count value or the second count value.
Writing to the second non-volatile memory upon completion of print processing, rather than during print processing when high-voltage power is being supplied to the printing unit, allows the correct count value to be stored in the second non-volatile memory.
It is preferable if the controller does not supply power to the second non-volatile memory during print processing, but does supply power to the second non-volatile memory at least during writing to the second non-volatile memory upon completion of the print processing. This prevents malfunction of the second non-volatile memory.
Also, the controller determines whether the printing unit has been replaced on the basis of a comparison of the first count value and the second count value after the occurrence of an incident in which there is the possibility that the printing unit has been exchanged.
Automatically determining whether the printing unit has been replaced allows the processing required when the printing unit has been replaced to be executed automatically, without any input by the user through the control panel to the effect that replacement is complete.
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patent: 5923917 (1999-07-01), Sakurai et al.
patent: 6014533 (2000-01-01), Kawana
patent: 6097908 (2000-08-01), Uchiyama et al.
patent: 08-69214 (1996-03-01), None
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patent: 10-52964 (1998-02-01), None
patent: 10-240091 (1998-09-01), None
patent: 10-254305 (1998-09-01), None
Itoh Fumihiro
Kojima Takeo
Wanou Masahiro
Watanabe Yoshihiro
Yamaguchi Yoshio
Armstrong Westerman Hattori McLeland & Naughton LLP
Chen Sophia S.
Fujitsu Limited
Tran Hoan
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