Image-transfer and sheet-separation apparatus

An apparatus for transferring onto a sheet an image retained on an image receiver and toner-developed from a positive latent image, and for subsequently separating the sheet from the image receiver, comprising:

• a transfer roller pressing on the image receiver for applying a bias voltage to the sheet, the bias voltage being within the range of 500 V to 2000 V and being composed of an AC voltage superimposed on a DC voltage, the DC voltage being within the range of 1000 V to 1500 V, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the image receiver, the DC voltage opposite polarity charge inducing transfer of the toner-developed image from the image receiver onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a bias voltage supply unit connected to the transfer roller;
• and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An apparatus for transferring onto a sheet an image retained on a rotatable photoconductor drum and toner-developed from a positive latent image, and for subsequently separating the sheet from the photoconductor drum, comprising:

• a transfer roller pressing on the photoconductor drum for applying a bias voltage to the sheet, the bias voltage being composed of an AC voltage superimposed on a DC voltage, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the photoconductor drum, the DC voltage opposite polarity charge inducing transfer of the toner-developed image from the photoconductor drum onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a bias voltage supply unit connected to the transfer roller;
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image;
• a case provided under the photoconductor drum, an upper portion of the case rotatably supporting the transfer roller;
• and
• moving means for moving the transfer roller toward and away from the photoconductor drum, the moving means including a rotatable eccentric wheel in contact with an underside of the case, a turning angle of the eccentric wheel corresponding to a thickness of the sheet.

An image reproducing apparatus comprising:

• a scanning unit for obtaining image information corresponding to an original image;
• an image forming unit including an image receiver, for developing a latent image corresponding to the image information retained on the image receiver with toner;
• and
• an image-transfer and sheet separating apparatus for transferring onto a sheet the toner-developed image retained on the image receiver, and for subsequently separating the sheet from the image receiver, the image-transfer and sheet-separating apparatus including
• a transfer roller pressing on the image receiver, for applying a bias voltage to the sheet, the bias voltage being within the range of 500 V to 2000 V and being composed of an AC voltage within the range of 1000 V to 1500 V superimposed on a DC voltage,
• a bias voltage supply unit connected to the transfer roller, and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An image reproducing apparatus comprising:

• a scanning unit for obtaining image information corresponding to an original image;
• an image forming unit including an image receiver for developing a latent image corresponding to the image information retained on the image receiver with toner;
• and
• an image-transfer and sheet separating apparatus for transferring onto a sheet the toner-developed image retained on the image receiver, and for subsequently separating the sheet from the image receiver, the image-transfer and sheet-separating apparatus including
• a transfer roller pressing on the image receiver, for applying a bias voltage to the sheet, the bias voltage being within the range of 500 V to 2000 V and composed of an AC voltage superimposed on a DC voltage, the DC voltage being within the range of 1000 V to 1500 V,
• a bias voltage supply unit connected to the transfer roller, and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An image reproducing apparatus comprising:

• a scanning unit for obtaining image information corresponding to an original image;
• an image forming unit including a rotatable photoconductor drum for developing a latent image corresponding to the image information retained on the photoconductor drum with toner;
• and
• an image-transfer and sheet separating apparatus for transferring onto a sheet the toner-developed image retained on the photocondutor drum, and for subsequently separating the sheet from the photoconductor drum, the image-transfer and sheet-separating apparatus including
• a transfer roller pressing on the photoconductor drum, for applying a bias voltage composed of an AC voltage superimposed on a DC voltage to the sheet,
• a bias voltage supply unit connected to the transfer roller, and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image;
• a case provided under the photoconductor drum, an upper portion the case rotatably supporting the transer roller;
• and
• moving means for moving the transfer roller toward and away from the photoconductor drum, the moving means including a rotatable eccentric wheel in contact with an underside of the case, a turning angle of the eccentric wheel corresponding to a thickness of the sheet.

An apparatus for transferring onto a sheet an image retained on an image receiver and toner-developed from a positive latent image, and for subsequently separating the sheet from the image receiver, comprising:

• a transfer roller pressing on the image receiver for applying a bias voltage to the sheet, the bias voltage being composed of an AC voltage within the range of 1000 V to 1500 V superimposed on a DC voltage, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the image receiver, the DC voltage opposite polarity charge inducing transfer of the toner-developed image from the image receiver onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a bias voltage supply unit connected to the transfer roller;
• and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An apparatus for transferring onto a sheet an image retained on an image receiver and toner-developed from a positive latent image, and for subsequently separating the sheet from the image receiver, comprising:

• a transfer roller pressing on the image receiver for applying a bias voltage to the sheet, the bias voltage being composed of an AC voltage superimposed on a DC voltage, the DC voltage being within the range of 1000 V to 1500 V, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the image receiver, the DC voltage opposite polarity charge inducing transfer of the toner-developed image from the image receiver onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a bias voltage supply unit connected to the transfer roller;
• and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An image reproducing apparatus comprising:

• a scanning unit for obtaining image information corresponding to an original image;
• an image forming unit including an image receiver for developing a latent image corresponding to the image information retained on the image receiver with toner;
• and
• an image-transfer and sheet separating apparatus for transferring onto a sheet the toner-developed image retained on the image receiver, and for subsequently separating the sheet from the image receiver, the image-transfer and sheet-separating apparatus including
• a transfer roller pressing on the image receiver, for applying a bias voltage to the sheet, the bias voltage being composed of an AC voltage within the range of 1000 V to 1500 V superimposed on a DC voltage,
• a bias voltage supply unit connected to the transfer roller, and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An image reproducing apparatus comprising:

• a scanning unit for obtaining image information corresponding to an original image;
• an image forming unit including an image receiver for developing a latent image corresponding to the image information retained on the image receiver with toner;
• and
• an image-transfer and sheet separating apparatus for transferring onto a sheet the toner-developed image retained on the image receiver, and for subsequently separating the sheet from the image receiver, the image-transfer and sheet-separating apparatus including
• a transfer roller pressing on the image receiver, for applying a bias voltage to the sheet, the bias voltage being composed of an AC voltage superimposed on a DC voltage, the DC voltage being within the range of 1000 V to 1500 V,
• a bias voltage supply unit connected to the transfer roller, and
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An image forming and transferring apparatus in a photocopying machine, comprising:

• an image receiver disposed centrally within the photocopying machine;
• a main charger disposed in a position adjacent to and above the image receiver, for electrically charging the image receiver to a predetermined level, such that an electrostatic positive latent image may be formed thereon;
• a developing unit for developing an electrostatic positive latent image on the image receiver with toner;
• a transfer roller pressing on the image receiver, for transferring a toner-developed image retained on the image receiver onto a sheet;
• means for separating the sheet from the image receiver by applying a bias voltage to the sheet through the transfer roller, the bias voltage being composed of an AC voltage superimposed on a DC voltage, the DC voltage being within the range of 1000 V to 1500 V, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the image receiver, the DC voltage opposite polarity charge inducing transfer of the toner developed image from the image receiver onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An image forming and transferring apparatus in a photocopying machine, comprising:

• an image receiver disposed centrally within the photocopying machine;
• a main charger disposed in a position adjacent to and above the image receiver, for electrically charging the image receiver to a predetermined level, such that an electrostatic positive latent image may be formed thereon;
• a developing unit for developing an electrostatic positive latent image on the image receiver with toner;
• a transfer roller pressing on the image receiver, for transferring a toner-developed image retained on the image receiver onto a sheet;
• means for separating the sheet from the image receiver by applying a bias voltage to the sheet through the transfer roller, the bias voltage being composed of an AC voltage within the range of 1000 V to 1500 V superimposed on a DC voltage, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the image receiver, the DC voltage opposite polarity charge inducing transfer of the toner developed image from the image receiver onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An image forming and transferring apparatus in a photocopying machine, comprising:

• an image receiver disposed centrally within the photocopying machine;
• a main charger disposed in a position adjacent to and above the image receiver, for electrically charging the image receiver to a predetermined level, such that an electrostatic positive latent image may be formed thereon;
• a developing unit for developing an electrostatic positive latent image on the image receiver with toner;
• a transfer roller pressing on the image receiver, for transferring a toner-developed image retained on the image receiver onto a sheet;
• means for separating the sheet from the image receiver by applying a bias voltage to the sheet through the transfer roller, the bias voltage being within the range of 500 V to 2000 V and composed of an AC voltage superimposed on a DC voltage being within the range of 1000 V to 1500 V, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the image receiver, the DC voltage opposite polarity charge inducing transfer of the toner developed image from the image receiver onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image.

An apparatus in a photocopying machine, comprising:

• a rotatable photoconductor drum disposed centrally within the photocopying machine;
• a main charger disposed in a position adjacent to and above the photoconductor drum, for electrically charging the photoconductor drum to a predetermined level, such that an electrostatic positive latent image may be formed thereon;
• a developing unit for developing an electrostatic positive latent image on the photoconductor drum with toner;
• a transfer roller pressing on the photoconductor drum, for transferring a toner-developed image retained on the photoconductor drum onto a sheet;
• means for separating the sheet from the photoconductor drum by applying a bias voltage to the sheet through the transfer roller, the bias voltage being composed of an AC voltage superimposed on a DC voltage, such that
• the DC voltage charges the sheet with a charge having a polarity opposite to a charge carried by the toner that causes the toner-developed image to adhere to the photoconductor drum, the DC voltage opposite polarity charge inducing transfer of the toner developed image from the photoconductor drum onto the sheet, and
• the AC voltage electrically discharges the sheet from the transfer roller;
• a charge-stripping brush for removing remnant electric charge from the sheet after the sheet is discharged by the AC voltage, the charge-stripping brush being provided in a position forward of the transfer roller along a transport direction of the sheet during the image transferring, such that an edge of the brush contacts a surface of the sheet opposite to that containing the transferred toner-developed image;
• a case provided under the photoconductor drum, an upper portion of the case rotatably supporting the transfer roller;
• and
• moving means for moving the transfer roller toward and away from the photoconductor drum, the moving means including a rotatable eccentric wheel in contact with an underside of the case, a turning angle of the eccentric wheel corresponding to a thickness of the sheet.