Image forming apparatus to calculate film thicknesses of a photoconductor film of a photoconductor, image forming method, and non-transitory recording medium storing image forming program

Patent metadata

Field	Value
Publication number	US-10606202-B2
Application number	US-201816183874-A
Country	US
Kind code	B2
Filing date	Nov 8, 2018
Priority date	Nov 13, 2017
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

An image forming apparatus includes a photoconductor, a charging roller to charge the photoconductor, a power source to apply a charging bias to the charging roller, a current sensor to generate a feedback signal representing an output current flowing from the charging roller to the photoconductor, a memory, and circuitry. The circuitry calculates film thicknesses of a photoconductor film of the photoconductor at a plurality of points of time based on a voltage of the charging bias and the output current, calculates travel distances of the photoconductor charged at the plurality of points of time, associates the film thicknesses with the travel distances, stores the film thicknesses and the travel distances in the memory, calculates a present estimated film thickness based on the film thicknesses and the travel distances, and calculates an estimated film thickness range corresponding to a present travel distance based on the present estimated film thickness.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a photoconductor that is rotatable;
a charging roller to charge a surface of the photoconductor;
a power source to apply a charging bias to the charging roller;
a current sensor to generate a signal representing an output current flowing from the charging roller to the photoconductor;
a memory; and
circuitry to:
calculate film thicknesses of a photoconductor film of the photoconductor at a plurality of points of time, based on a voltage of the charging bias applied to the charging roller and the signal representing the output current flowing to the photoconductor;
calculate travel distances of the photoconductor charged by the charging roller at the plurality of points of time;
associate the film thicknesses with the travel distances and store the film thicknesses and the travel distances in the memory;
calculate a present estimated film thickness, based on the film thicknesses and the travel distances acquired from the memory; and
calculate an estimated film thickness range corresponding to a present travel distance, based on the present estimated film thickness.

2. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to calculate the present estimated film thickness using a least square method, based on the film thicknesses and the travel distances acquired from the memory.

3. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to determine whether the present estimated film thickness is valid or invalid in a next film thickness estimation, based on whether the present estimated film thickness falls within the estimated film thickness range.

4. The image forming apparatus according to claim 3 ,
wherein the circuitry is configured to determine that the present estimated film thickness is invalid upon the present estimated film thickness being relatively greater than an upper limit value of the estimated film thickness range.

5. The image forming apparatus according to claim 3 ,
wherein the circuitry is configured to count an out-of-range count that is counted upon the present estimated film thickness being relatively smaller than a lower limit value of the estimated film thickness range, and
wherein the circuitry is configured to determine that the present estimated film thickness, relatively smaller than the lower limit value, is valid upon the out-of-range count being continuously counted a predetermined number of times or greater.

6. The image forming apparatus according to claim 5 ,
wherein, upon the circuitry determining that the present estimated film thickness is valid, the circuitry is configured to delete previously stored film thicknesses from the memory, before the present estimated film thickness becomes relatively smaller than the lower limit value of the estimated film thickness range.

7. The image forming apparatus according to claim 3 ,
wherein the circuitry is configured to count an out-of-range count that is counted upon the present estimated film thickness being out of the estimated film thickness range, and
wherein the circuitry is configured to not use the present estimated film thickness to estimate a life of the photoconductor upon the out-of-range count being continuously counted a predetermined number of times or greater.

8. The image forming apparatus according to claim 1 ,
wherein the memory is configured to store film thickness error estimation data,
wherein the circuitry is configured to calculate an estimated film thickness error at the present estimated film thickness based on the film thickness error estimation data and the present estimated film thickness, and
wherein the circuitry is configured to calculate the estimated film thickness range based on the present estimated film thickness and the estimated film thickness error.

9. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to calculate the estimated film thickness range to be relatively narrower as a previous estimated film thickness value is relatively smaller.

10. The image forming apparatus according to claim 1 , further comprising a temperature and humidity sensor to detect temperature and humidity,
wherein the circuitry is configured to correct the present estimated film thickness based on the temperature and humidity detected by the temperature and humidity sensor.

11. The image forming apparatus according to claim 1 , further comprising a temperature and humidity sensor to detect temperature and humidity,
wherein the memory is configured to store film thickness error estimation data,
wherein the circuitry is configured to calculate an estimated film thickness error at the present estimated film thickness based on the film thickness error estimation data and the present estimated film thickness, and
wherein the circuitry is configured to correct the estimated film thickness error based on the temperature and humidity detected by the temperature and humidity sensor.

12. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to count an out-of-range count that is counted upon the present estimated film thickness being relatively greater than an upper limit value of the estimated film thickness range and upon the present estimated film thickness being relatively smaller than a lower limit value of the estimated film thickness range, and
wherein, before the out-of-range count is continuously counted a predetermined number of times or more, the circuitry is configured to calculate the present estimated film thickness again.

13. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to calculate a usage rate of the photoconductor based on a lower limit value of the estimated film thickness range.

14. The image forming apparatus according to claim 13 ,
wherein the circuitry is configured to compare the lower limit value of the estimated film thickness range and a maximum wearing film thickness calculated based on a travel distance of the photoconductor, upon the photoconductor film being scraped to a maximum amount; and
wherein the circuitry is configured to calculate the usage rate of the photoconductor based on a relatively larger of the lower limit value of the estimated film thickness range and the maximum wearing film thickness.

15. The image forming apparatus according to claim 13 ,
wherein the circuitry is configured to calculate the usage rate of the photoconductor based on the lower limit value of the estimated film thickness range after a travel distance of the photoconductor exceeds a threshold value.

16. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to calculate the estimated film thickness range corresponding to the present travel distance using an estimated film thickness error based on a previous estimated film thickness.

17. The image forming apparatus according to claim 1 ,
wherein the circuitry includes a usable remaining days calculator, and is configured to use the usable remaining days calculator to calculate usable remaining days of the photoconductor.

18. The image forming apparatus according to claim 17 ,
wherein the circuitry is configured to store an estimated film thickness and time data in the memory upon the travel distance of the photoconductor calculated by the circuitry becoming relatively greater than a threshold, and
wherein the circuitry is configured to calculate the usable remaining days of the photocon

Assignees

• Matsuno Yasuhide
• Yoshimi Takahiro
• Minami Shinji
• Ricoh Co Ltd

Inventors

• Matsuno Yasuhide
• Yoshimi Takahiro
• Minami Shinji

Classifications

• G03G15/751

  relating to drum (G03G15/757 takes precedence) · CPC title

• G03G15/5033 Primary

  by measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor · CPC title

• G03G2215/00071

  by measuring the photoconductor or its environmental characteristics · CPC title

• G03G15/553

  Monitoring or warning means for exhaustion or lifetime end of consumables, e.g. indication of insufficient copy sheet quantity for a job · CPC title

• G03G15/0266

  Arrangements for controlling the amount of charge · CPC title