In this transfer device, when a straight line is regarded to be a support axis P connecting a press-contacting point between the first roller and the drum to a press-contacting point between the second roller and the stopper, a moment of the resilient member of the second roller side to the support axis P is larger than the sum of a moment of the resilient member of the first roller side to the support axis P and a moment of the resilient means to the support axis P. Upon adjusting the moments as described above, a stable and reliable contact is maintained at the pair of press-contacting points of the positioning roller to the drum, completely preventing the deviation in the press-contacting points, stably and reliably limiting the gap between the transfer roller and the drum, and, hence, forming an excellently transferred image.
The invention provides an image forming apparatus including an image bearing member, a transfer member for transferring a toner image from the image bearing member, and a first contact portion and a second contact portion which can be mutually contacted for applying a voltage to the transfer member, the first contact portion having a convex portion, wherein the transfer member is pressed toward the image bearing member by a pressure exerted between the first contact portion and the second contact portion, and the convex portion has a hardness larger than that of the second contact portion. It is rendered possible to prevent an intrusion of toner or the like into the electrical contact portion, thus resulting in a contact failure.
An image forming device sheet conveyance and guide mechanism 6 has a first pre-transfer guide plate 61 and a second pre-transfer guide plate 62. The first pre-transfer guide plate 61 is provided on the transfer roller side upstream of the transfer nip in a transfer sheet conveying direction, and guides a transfer sheet into the transfer nip. The second pre-transfer guide plate 62 is provided opposite to the first pre-transfer guide plate 61 and on the photoconductive drum side upstream of the transfer nip in the transfer sheet conveying direction, and guides a transfer sheet into the transfer nip. The first pre-transfer guide plate 61 is provided with contact portions 64 protruding toward the second pre-transfer guide plate 62, and the second pre-transfer guide plate 62 is provided with semiconductor members 63 in contact with the contact portions 64.
An image forming device is disclosed that can control image blurring, image contraction, and the like when resilient transfer media such as cardboard is to be transported upward from a pair of resist rollers and guided to a transfer position, and obtain a suitable transfer image. Transfer media is transported upward by resist rollers, and guided toward a transfer position by a pair of guide plates. Because tip of a resilient transfer medium such as cardboard may spring back to its original shape after it separates from the resist rollers, one guide plate is urged toward the transfer position by spring members, and can absorb the springing of the transfer media back to its original shape by pivoting away from the transfer position, and thus can reduce the occurrences of image blurring or the like.
In a recording medium conveying mechanism for an image forming apparatus of the present invention, a first and a second rotary body rotate in contact with each other for conveying a paper sheet to which a toner image is to be transferred. The first and second rotary bodies are respectively mounted on the apparatus body and an openable cover mounted on the apparatus body. The second rotary body moves into or out of contact with the first rotary body in interlocked relation to the closing or the opening, respectively, of the cover. The conveying mechanism includes a first support member rotatably supporting the first rotary body on the apparatus body and including a first engaging portion. A second support member rotatably supports the second rotary body on the cover and includes a second engaging portion. The first and second engaging portions mate with each other when the cover is closed.
An image forming apparatus of the present invention includes an intermediate transfer belt to which a toner image is transferred from an image carrier. A transfer roller contacts the intermediate transfer belt, forming a nip for image transfer. The transfer roller causes the toner image to be transferred from the intermediate transfer belt to a recording medium at the nip. A first and a second guide member cooperate to guide the recording medium to the nip. The end of the second guide member is positioned at the intermediate transfer belt side with respect to a line connecting a restriction point included in the first guide member and the inlet of the nip. This configuration causes a portion of the recording medium rearward of a portion entered the nip to bend in a convex configuration. The recording medium therefore surely remains in close contact with the intermediate transfer belt in a region where pretransfer is apt to occur.
