| 摘要 |
A recording material is held and conveyed by a registration nip portion of a registration roller pair, a secondary transfer portion, and a fixing nip portion of a fixing device, respectively. The conveyance speed of the recording material in the secondary transfer portion is set to be higher than that in the fixing nip portion, and the recording material has a flexed shape between the secondary transfer portion and the fixing nip portion. The conveyance speed in the registration nip portion is increased after a leading edge of the recording material reaches the fixing nip portion. With this configuration, a force exerted on an intermediate transfer belt is canceled out with stiffness of the recording material. |
| 主权项 |
1. An image forming apparatus, comprising:
a movable endless belt; a toner image forming unit configured to form a toner image on the belt; a transfer rotary member forming, between the transfer rotary member and the belt, a transfer nip portion configured to transfer the toner image borne on the belt onto a recording material, the recording material being conveyed at a speed of Vt in the transfer nip portion; a pair of conveyance members arranged upstream of the transfer nip portion in a conveyance direction of the recording material, and configured to convey the recording material to the transfer nip portion, the pair of conveyance members forming a conveyance nip portion; a first drive source configured to drive at least one of the pair of conveyance members so that the recording material is conveyed at a speed of Vr in the conveyance nip portion; a pair of fixing members arranged downstream of the transfer nip portion in the conveyance direction of the recording material, and configured to fix the toner image, which has been transferred onto the recording material in the transfer nip portion, onto the recording material, the pair of fixing members forming a fixing nip portion; a second drive source configured to drive at least one of the pair of fixing members so that the recording material is conveyed at a speed of Vf in the fixing nip portion; an input portion into which information on a basis weight or a thickness of the recording material onto which the toner image is transferred is input; and a control portion configured to: control a drive speed of the first drive source so that the Vr is higher than the Vt when the recording material is conveyed in the transfer nip portion; control a drive speed of the second drive source so that a flexed state is formed in the recording material between the transfer nip portion and the fixing nip portion during a period included in a period during which the recording material is conveyed to both the transfer nip portion and the fixing nip portion; and control, when the information input into the input portion exceeds a predetermined basis weight or a predetermined thickness, the drive speed of the first drive source so that Vr1 is higher than Vr0, where the Vr0 represents the Vr during a period which is before a downstream edge of the recording material in the conveyance direction reaches the fixing nip portion, and during which the recording material is conveyed to the conveyance nip portion, and the Vr1 represents the Vr during a period which is after the downstream edge of the recording material in the conveyance direction reaches the fixing nip portion, and is included in a period during which the recording material is conveyed to the conveyance nip portion. |
