JP2015114604A5 - - Google Patents

Description

In order to achieve the above object, the present invention comprises a plurality of image carriers on which toner images are formed on the surface, an intermediate transfer member to which the toner images on the image carrier are transferred, and a cored bar, A primary transfer nip forming member that contacts the image carrier via the intermediate transfer member to form a primary transfer nip; and a secondary transfer nip forming member that contacts the intermediate transfer member to form a secondary transfer nip; A transfer bias applying means for applying a transfer bias for forming a transfer electric field in the secondary transfer nip, and the transfer bias applying means transfers the toner image to a recording medium at the secondary transfer nip. In an image forming apparatus that sometimes applies a transfer bias in which an alternating current component and a direct current component are superimposed, the diameter of the core metal of the primary transfer nip forming member overlaps the alternating current component and the direct current component in the secondary transfer nip. Transcription So as not to cause discharge upon application of a bias, characterized in that it is set to a size capable of suppressing toner charge deviation at the primary transfer.

Claims (9)

A plurality of image carriers on which toner images are formed; and
An intermediate transfer member to which a toner image on the image carrier is transferred;
A primary transfer nip forming member that has a metal core, contacts the image carrier via the intermediate transfer body, and forms a primary transfer nip;
A secondary transfer nip forming member that forms a secondary transfer nip in contact with the intermediate transfer member;
A transfer bias applying means for applying a transfer bias for forming a transfer electric field in the secondary transfer nip;
With
In the image forming apparatus in which the transfer bias applying unit applies a transfer bias in which an alternating current component and a direct current component are superimposed when the toner image is transferred to a recording medium at the secondary transfer nip .
The diameter of the core bar of the primary transfer nip forming member is such that the charge of the toner during primary transfer does not cause discharge when a transfer bias in which an AC component and a DC component are superimposed is applied in the secondary transfer nip. An image forming apparatus, wherein the image forming apparatus is set to a size capable of suppressing a deviation. The image forming apparatus according to claim 1.
The diameter of the said metal core is 10.4 mm or more, The image forming apparatus characterized by the above-mentioned. The image forming apparatus according to claim 1, wherein
When the pressing forces at both ends of the primary transfer nip forming member for contact with the image carrier are F and R, the values of F and R are:
(F−R) / (F + R) × 100 ≦ 30
An image forming apparatus characterized by satisfying the above. The image forming apparatus according to any one of claims 1 to 3,
The transfer bias applying means records the toner from the intermediate transfer member in the secondary transfer nip in the secondary transfer nip so that the time average potential in one cycle of the superimposed transfer bias is larger than the center value of the maximum potential and the minimum potential in one cycle. An image forming apparatus that outputs a transfer bias shifted to a side that facilitates electrostatic transfer to a medium. The image forming apparatus according to any one of claims 1 to 3,
The transfer bias applying unit is configured so that the intermediate time from the surface of the recording medium in the secondary transfer nip is a positive time that is a positive time within one cycle of the superimposed transfer bias or a negative time that is a negative polarity. An image forming apparatus, wherein a transfer bias that outputs 0.03 [msec] or more contributes to the toner returning to the surface of the transfer body. The image forming apparatus according to any one of claims 1 to 4,
The frequency of the bias of the AC component is f [Hz], the nip width that is the length in the moving direction of the intermediate transfer member in the secondary transfer nip is d [mm], and the surface moving speed of the intermediate transfer member is v [ mm / s]
f> (4 / d) × v
An image forming apparatus having the condition: In the image forming apparatus according to any one of claims 1 to 6,
The transfer bias applying means has a configuration capable of selectively applying a transfer bias in which an alternating current component and a direct current component are superimposed and a transfer bias of only a direct current component. apparatus. A plurality of image carriers on which toner images are formed; and
An intermediate transfer member to which a toner image on the image carrier is transferred;
A primary transfer nip forming member that has a metal core, contacts the image carrier via the intermediate transfer body, and forms a primary transfer nip;
A secondary transfer nip forming member that forms a secondary transfer nip in contact with the intermediate transfer member;
A transfer bias applying means for applying a transfer bias for forming a transfer electric field in the secondary transfer nip;
With
In the image forming apparatus in which the transfer bias applying unit applies a transfer bias in which an alternating current component and a direct current component are superimposed when the toner image is transferred to a recording medium at the secondary transfer nip.
An image forming apparatus, wherein a diameter of the cored bar of the primary transfer nip forming member is 10.4 mm or more. The image forming apparatus according to claim 8.
When the pressing forces at both ends of the primary transfer nip forming member for contact with the image carrier are F and R, the values of F and R are:
(F−R) / (F + R) × 100 ≦ 30
An image forming apparatus characterized by satisfying the above.