Image forming apparatus controlling transfer bias based on temperature and humidity

Patent metadata

Field	Value
Publication number	US-9632461-B2
Application number	US-201514956707-A
Country	US
Kind code	B2
Filing date	Dec 2, 2015
Priority date	Dec 9, 2014
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

An image forming apparatus includes an image bearer, a toner image forming device, a nip forming device, a power source, a controller, and a temperature-and-humidity detector. The toner image forming device forms a toner image on the image bearer. The nip forming device contacts the image bearer to form a transfer nip. The power source outputs a transfer bias, in which an alternating current component is superimposed on a direct current component, to transfer the toner image onto a recording medium interposed in the transfer nip. The temperature-and-humidity detector detects a temperature and humidity. The controller controls the power source to output the transfer bias including the direct current component with a smaller absolute value as at least one of the detected temperature and humidity increases.

First claim

What is claimed is:

1. An image forming apparatus, comprising:
an image bearer;
a toner image forming device to form a toner image on the image bearer;
a nip forming device contacting the image bearer to form a transfer nip;
a power source to output a transfer bias, in which an alternating current component is superimposed on a direct current component, to transfer the toner image from the image bearer onto a recording medium interposed in the transfer nip;
a detector to detect at least one of a temperature and a humidity; and
a controller operatively connected to the power source to control the power source to output the transfer bias in which the direct current component of the transfer bias has a smaller absolute value as at least one of the detected temperature and the detected humidity increases,
wherein the controller controls the power source to output the transfer bias having a duty greater than 50% when transferring the toner image onto the recording medium, and the duty is expressed by (T−A)/T×100% when A denotes a duration of a peak voltage that transfers the toner image from the image bearer onto the recording medium and T denotes a time period of a cycle of the alternating current component of the transfer bias.

2. An image forming apparatus, comprising:
an image bearer;
a toner image forming device to form a toner image on the image bearer;
a nip forming device contacting the image bearer to form a transfer nip;
a power source to output a transfer bias, in which an alternating current component is superimposed on a direct current component, to transfer the toner image from the image bearer onto a recording medium interposed in the transfer nip;
a detector to detect at least one of a temperature and a humidity; and
a controller operatively connected to the power source to control the power source to output the transfer bias in which the direct current component of the transfer bias has a smaller absolute value as at least one of the detected temperature and the detected humidity increases,
wherein the controller controls the power source to output the transfer bias in which the alternating current component of the transfer bias has a higher voltage between peaks as the at least one of the detected temperature and the detected humidity increases.

3. The image forming apparatus according to claim 1 , wherein the controller controls the power source to output the transfer bias including the alternating current component having a polarity that alternates at a predetermined cycle.

4. The image forming apparatus according to claim 1 , wherein the controller controls the power source to output the transfer bias including the alternating current component with a voltage between peaks of 0 V when the at least one of the detected temperature and the detected humidity is lower than a predetermined value.

5. The image forming apparatus according to claim 1 , wherein the image bearer is a multi-layer belt having a plurality of layers that includes a base layer and an elastic layer on the base layer.

6. The image forming apparatus according to claim 5 , wherein the elastic layer includes a plurality of particles dispersed over a surface of the elastic layer.

7. The image forming apparatus according to claim 6 , wherein the plurality of particles has a polarity opposite to a normal charge polarity of toner of the toner image.

8. The image forming apparatus according to claim 6 , wherein the plurality of particles has a same polarity as a normal charge polarity of toner of the toner image.

9. The image forming apparatus according to claim 5 , wherein the plurality of layers includes a coating layer on the elastic layer.

10. The image forming apparatus according to claim 1 , wherein the image bearer is a multi-layer belt having a plurality of layers that includes a resin layer.

11. The image forming apparatus according to claim 1 , wherein the image bearer is an endless belt.

12. An image forming apparatus, comprising:
an image bearer;
a toner image forming device to form a toner image on the image bearer;
a nip forming device contacting the image bearer to form a transfer nip;
a power source to output a transfer bias to transfer the toner image from the image bearer onto a recording medium interposed in the transfer nip;
a detector to detect at least one of a temperature and a humidity; and
a controller operatively connected to the power source to control the power source to output the transfer bias consisting only of a direct current component when the at least one of the detected temperature and the detected humidity is lower than a predetermined value, and to output the transfer bias in which an alternating current component is superimposed on the direct current component when the at least one of the detected temperature and the detected humidity is equal to or higher than the predetermined value.

13. The image forming apparatus according to claim 12 , wherein the controller controls the power source to output the transfer bias having a duty greater than 50% when transferring the toner image onto the recording medium, and the duty is expressed by (T−A)/T×100% when A denotes a duration of a peak voltage that transfers the toner image from the image bearer onto the recording medium and T denotes a time period of a cycle of an alternating current component of the transfer bias.

14. The image forming apparatus according to claim 12 , wherein the image bearer is a multi-layer belt having a plurality of layers that includes a base layer and an elastic layer on the base layer.

15. The image forming apparatus according to claim 14 , wherein the elastic layer includes a plurality of particles dispersed over a surface of the elastic layer.

16. The image forming apparatus according to claim 15 , wherein the plurality of particles has a polarity opposite to a normal charge polarity of toner of the toner image.

17. The image forming apparatus according to claim 15 , wherein the plurality of particles has a same polarity as a normal charge polarity of toner of the toner image.

18. The image forming apparatus according to claim 14 , wherein the plurality of layers includes a coating layer on the elastic layer.

19. The image forming apparatus according to claim 12 , wherein the image bearer is a multi-layer belt having a plurality of layers that includes a resin layer.

20. The image forming apparatus according to claim 12 , wherein the image bearer is an endless belt.

21. The image forming apparatus according to claim 1 ,
wherein the controller controls the power source to output the transfer bias in which the direct current component of the transfer bias has a smaller absolute value as an absolute humidity calculated from the detected temperature and the detected humidity increases.

22. The image forming apparatus according to claim 2 ,
wherein the controller controls the power source to output the transfer bias in which the direct current component of the transfer bias has a smaller absolute value as an absolute humidity calculated from the detected temperature and the detected humidity increases, and
wherein the controller controls the power source to output the transfer bias in which the alternating current component of the transfer bias has a higher voltage between peaks as the absolute humidity increases.

23. The image forming apparatus according to claim 12 ,
wherein the controller controls the power source to output the transfer bias consis

Assignees

• Sugiura Kenji
• Yamaguchi Toshitaka
• Haga Hiroyoshi
• Ishii Hirokazu
• Tanaka Shinya
• Mizutani Takehide
• Wada Yuuji
• Ohsugi Tatsuya
• Kumagai Naohiro
• Kogure Seiichi
• Fujita Junpei
• Yogosawa Kazuki
• Ricoh Co Ltd

Inventors

• Sugiura Kenji
• Yamaguchi Toshitaka
• Haga Hiroyoshi
• Ishii Hirokazu
• Tanaka Shinya
• Mizutani Takehide
• Wada Yuuji
• Ohsugi Tatsuya
• Kumagai Naohiro
• Kogure Seiichi
• Fujita Junpei
• Yogosawa Kazuki

Classifications

• G03G21/20

  Humidity or temperature control {also ozone evacuation; Internal apparatus environment control} · CPC title

• G03G15/1675 Primary

  with means for controlling the bias applied in the transfer nip · CPC title

• G03G15/1665 Primary

  by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat · CPC title