Transfer device for forming a stable transfer electric field, and an image forming apparatus including the transfer device

A transfer device that transfers a visual image from an image carrier to a recording medium, comprising:

• a first transfer element configured to move and receive the visual image from the image carrier on a first surface of the first transfer element;
• a second transfer element provided opposite to the first surface of the first transfer element to pinch and convey the recording medium through a transfer nip part formed between the first surface of the first transfer element and the second transfer element;
• a facing member provided on a second surface of the first transfer element opposite to the first surface of the first transfer element, the facing member facing the second transfer element via the first transfer element and including an electrode;
• a constant-current power supply configured to apply an electric current voltage to the electrode of the facing member to transfer the visual image on the first surface of the first transfer element to the recording medium at the transfer nip part;
• an electric current detecting device configured to detect an amount of an electric current passing through the recording medium, the electric current detecting device being provided upstream of the transfer nip part in a direction of conveyance of the recording medium;
• and
• a discharging device configured to discharge charge deposited on the recording medium, the discharging device being provided downstream of the transfer nip part in the direction of conveyance of the recording medium,
• wherein the electric current voltage applied to the electrode has a polarity equal to a polarity of the visual image and is subjected to a constant-current control.

An image forming apparatus, comprising:

• an image carrier configured to carry a visual image;
• a transfer device configured to transfer the visual image from the image carrier to a recording medium, the transfer device including,
• a first transfer element configured to move and receive the visual image from the image carrier on a first surface of the first transfer element, the first transfer element being in a shape of a belt,
• a second transfer element provided opposite to the first surface of the first transfer element to pinch and convey the recording medium through a transfer nip part formed between the first surface of the first transfer element and the second transfer element,
• a facing roller provided on a second surface of the first transfer element opposite to the first surface of the first transfer element, the facing roller facing the second transfer element via the first transfer element and including a core metal functioning as an electrode, and an elastic member of medium resistance formed around the core metal, and
• a constant-current power supply configured to apply an electric current voltage to the core metal of the facing roller to transfer the visual image on the first surface of the first transfer element to the recording medium,
• wherein the electric current voltage applied to the core metal has a polarity equal to a polarity of the visual image and is subjected to a constant-current control.

An image forming apparatus, comprising:

• an image carrier configured to carry a visual image;
• a transfer device configured to transfer the visual image from the image carrier to a recording medium, the transfer device including,
• a first transfer element configured to move and receive the visual image from the image carrier on a first surface of the first transfer element,
• a second transfer element provided opposite to the first surface of the first transfer element to pinch and convey the recording medium through a transfer nip part formed between the first surface of the first transfer element and the second transfer element,
• a facing member provided on a second surface of the first transfer element opposite to the first surface of the first transfer element, the facing member facing the second transfer element via the first transfer element and including an electrode,
• a constant-current power supply configured to apply an electric current voltage to the electrode of the facing member to transfer the visual image on the first surface of the first transfer element to the recording medium at the transfer nip part,
• an electric current detecting device configured to detect an amount of an electric current passing through the recording medium, the electric current detecting device being provided upstream of the transfer nip part in a direction of conveyance of the recording medium, and
• a discharging device configured to discharge charge deposited on the recording medium, the discharging device being provided downstream of the transfer nip part in the direction of conveyance of the recording medium,
• wherein the electric current voltage applied to the electrode has a polarity equal to a polarity of the visual image and is subjected to a constant-current control.

An image transferring method, comprising:

• moving a first transfer element in a shape of a belt which receives a visual image from an image carrier on a first surface of the first transfer element;
• conveying a recording medium to a transfer nip part formed between the first transfer element and a second transfer element provided opposite to the first surface of the first transfer element;
• applying an electric current voltage from a constant-current power supply to an electrode of a facing member provided on a second surface of the first transfer element opposite to the first surface of the first transfer element;
• and
• transferring the visual image on the first surface of the first transfer element to the recording medium,
• wherein the electric current voltage applied to the electrode has a polarity equal to a polarity of the visual image and is subjected to a constant-current control.

An image forming apparatus, comprising:

• carrying means for carrying a visual image;
• transferring means for transferring the visual image from the carrying means to a recording medium, the transferring means including,
• first transfer means for moving and receiving the visual image from the carrying means on a first surface of the first transfer means, the first transfer means being in a shape of a belt,
• second transfer means for pinching and conveying the recording medium through a transfer nip part formed between the first surface of the first transfer means and the second transfer means, the second transfer means being provided opposite to the first surface of the first transfer means,
• a facing roller provided on a second surface of the first transfer means opposite to the first surface of the first transfer means, the facing roller facing the second transfer means via the first transfer means and including a core metal functioning as an electrode, and an elastic member of medium resistance formed around the core metal, and
• applying means for applying an electric current voltage to the core metal of the facing roller to transfer the visual image on the first surface of the first transfer means to the recording medium,
• wherein the electric current voltage applied to the core metal has a polarity equal to a polarity of the visual image and is subjected to a constant-current control.

An image forming apparatus, comprising:

• carrying means for carrying a visual image;
• transferring means for transferring the visual image from the carrying means to a recording medium, the transferring means including,
• first transfer means for moving and receiving the visual image from the carrying means on a first surface of the first transfer means,
• second transfer means for pinching and conveying the recording medium through a transfer nip part formed between the first surface of the first transfer means and the second transfer means, the second transfer means being provided opposite to the first surface of the first transfer means,
• a facing member provided on a second surface of the first transfer means opposite to the first surface of the first transfer means, the facing member facing the second transfer means via the first transfer means and including an electrode,
• applying means for applying an electric current voltage to the electrode of the facing member to transfer the visual image on the first surface of the first transfer means to the recording medium at the transfer nip part,
• electric current detecting means for detecting an amount of an electric current passing through the recording medium, the electric current detecting means being provided upstream of the transfer nip part in a direction of conveyance of the recording medium, and
• discharging means for discharging charge deposited on the recording medium, the discharging means being provided downstream of the transfer nip part in the direction of conveyance of the recording medium,
• wherein the electric current voltage applied to the electrode has a polarity equal to a polarity of the visual image and is subjected to a constant-current control.