Image forming method and apparatus using an intermediate
First Claim
1. An image forming apparatus comprising:
- an image member,means for forming an electrostatic image on said image member,means for toning said electrostatic image to form a toner image on said image member,means for transferring said toner image to an intermediate sheet,means for overlaying said toner image on said intermediate sheet with a receiving sheet,means for heating said toner image and for urging said sheets together with sufficient pressure and heat to transfer and fuse said toner image to said receiving sheet in a single step, said means including means for moving said sheets at a first speed during said single transferring and fusing step,means for holding said sheets after said single transferring and fusing step while said toner image cools below its glass transition temperature, said holding means including means for either holding said sheets stationary or for transporting said sheets at a second speed less than said first speed, andmeans for separating said sheets after said toner image has cooled below its glass transition temperature.
2 Assignments
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Accused Products
Abstract
An image forming apparatus includes a source of at least one intermediate sheet which is preferably both thermally and electrically conductive. Toner images are transferred from one or more image members to the intermediate sheet under conditions of raised temperature and preferably with the assistance of an electric field. The toner image on the intermediate sheet is then overlaid with a receiving sheet and a combination of heat and pressure transfers and fuses the toner image to the receiving sheet in a single step, preferably while the sheets move at full machine speed. The sheets may then be slowed down or stopped, but are maintained together until cool at which point they are separated and the intermediate sheet fed back to the source of intermediate sheets. The image forming apparatus is particularly useful in creating multicolor toner images with small toners.
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Citations
39 Claims
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1. An image forming apparatus comprising:
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an image member, means for forming an electrostatic image on said image member, means for toning said electrostatic image to form a toner image on said image member, means for transferring said toner image to an intermediate sheet, means for overlaying said toner image on said intermediate sheet with a receiving sheet, means for heating said toner image and for urging said sheets together with sufficient pressure and heat to transfer and fuse said toner image to said receiving sheet in a single step, said means including means for moving said sheets at a first speed during said single transferring and fusing step, means for holding said sheets after said single transferring and fusing step while said toner image cools below its glass transition temperature, said holding means including means for either holding said sheets stationary or for transporting said sheets at a second speed less than said first speed, and means for separating said sheets after said toner image has cooled below its glass transition temperature. - View Dependent Claims (2, 3, 4, 5)
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6. An image forming apparatus comprising:
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one or more image members, means for forming a plurality of single color, different color toner images on said one or more image members, means for feeding an intermediate sheet having a leading and a trailing edge and a surface for receiving toner images into transfer relation with said one or more image members, means for transferring said toner images in overlying registration to said toner image receiving surface of said intermediate sheet to create a multicolor image thereon, said means including means for heating said intermediate sheet to at least the glass transition temperature of said toner images, means for feeding a receiving sheet into overlying relation with said multicolor image on said intermediate sheet, means for heating said multicolor toner image and for applying a force urging said intermediate sheet and receiving sheet together with pressure sufficient to transfer said multicolor image to said receiving sheet while said toner image is at or above its glass transition temperature, said force applying means including a pair of pressure members forming a nip through which said intermediate sheet and said receiving sheet are fed, one of said pressure members contacting said intermediate sheet, and means for separating said receiving sheet and intermediate sheet after the trailing edge of said intermediate sheet has left contact with said one pressure member, and said toner image has cooled below its glass transition temperature. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An image forming apparatus comprising:
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an image member, means for forming a series of electrostatic images on said image member, means for applying different color toners to said series of electrostatic images to form a series of different color single color toner images, a transfer drum, a supply for holding at least one intermediate sheet, said intermediate sheet having an image receiving surface and leading and trailing edges, means for feeding an intermediate sheet from said intermediate sheet supply onto the periphery of said transfer drum, means for holding said intermediate sheet on the periphery of the transfer drum, means for rotating said transfer drum to bring the image receiving surface of the intermediate sheet repeatedly into contact with toner images on said image member, means for transferring said toner images in registration to said receiving surface to form a multicolor image, said transferring means including, means for internally heating said transfer drum to a temperature sufficient to heat the intermediate sheet to a temperature sufficient to raise the toner images to their glass transition temperature when contacted by said intermediate sheet without damaging the image member, means for applying an electric field of a direction urging transfer of said toner images from said image member to said image receiving surface of said intermediate sheet, means for separating said intermediate sheet from said transfer drum, means for overlaying said multicolor toner image on said image receiving surface with a receiving sheet either before or after said intermediate sheet is separated from said transfer drum, roller means for applying pressure to said receiving and intermediate sheets and for maintaining the temperature of said toner image at or above its glass transition temperature to transfer said toner image to said receiving sheet and fuse it thereto in a single step, means for transporting said sheets away from said roller means sufficiently to allow said toner image to cool below its glass transition temperature, and means for separating said sheets after said toner image has cooled below its glass transition temperature and for returning said intermediate sheet to said intermediate sheet supply. - View Dependent Claims (22, 23, 24, 25)
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26. An image forming apparatus comprising:
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a plurality of image members, means for foraging a single color toner image on each of said image members with the colors of said toners varying from image member to image member, a cycleable transfer member, a source of at least one intermediate sheet, said intermediate sheet having leading and trailing edges and an image receiving surface, means for feeding an intermediate sheet from said source onto said transfer member, means for heating said intermediate sheet while on said transfer member, means for cycling said transfer member to bring the image receiving surface of an intermediate sheet on said transfer member through transfer relation with each of said image members to receive a different color toner image from each image member, means for separating said intermediate sheet from said transfer member, a source of receiving sheets, means for feeding a receiving sheet from said source of receiving sheets into overlying relation with the multicolor image on said image receiving surface of said intermediate sheet, roller means for applying a force urging said sheets together either before or after said intermediate sheet is separated from said transfer member, while moving said sheets at a first speed, means for maintaining the temperature of said toner image above said glass transition temperature while said sheets are passing through said roller means to transfer said multicolor toner image to said receiving sheet and fuse it thereon, means for feeding said intermediate sheet away from said temperature maintaining means at a second speed, less than said first speed, to allow said toner image to cool below its glass transition temperature, means for separating said sheets after said toner image is cooled below its glass transition temperature, and means for returning said intermediate sheet to said source of at least one intermediate sheet. - View Dependent Claims (27, 28)
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29. An image forming apparatus comprising:
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an image member, means for forming an electrostatic image on said image member, means for applying toner to said electrostatic image to form a toner image on said image member, said toner having a glass transition temperature, a source of at least one intermediate sheet having a finite length, said intermediate sheet being substantially metallic and both thermally and electrically conductive, means for bringing said intermediate sheet into transfer relation with said toner image in the presence of an electric field urging transfer of said toner image to said intermediate sheet, means for heating said intermediate sheet to a temperature sufficient to heat said toner image to its glass transition temperature when in transfer relation with said intermediate sheet, the combination of heat and electric field transferring said toner image to said intermediate sheet, means for overlying said intermediate sheet with a receiving sheet, means for urging said sheets together with sufficient pressure to transfer said toner image to said receiving sheet while said toner image is at or above its glass transition temperature, means for moving said sheets away from said urging means a sufficient distance to allow said toner image to cool, and means for separating said intermediate sheet from said receiving sheet after said toner image has cooled below its glass transition temperature. - View Dependent Claims (30)
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31. A method of forming a multicolor image, said method comprising:
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forming a series of single color, different color toner images on one or more image members, transferring said images in overlying registration to a surface of an intermediate sheet to form a multicolor image thereon, said sheet having leading and trailing edges and said surface being hard and smooth, each said transferring step including heating said intermediate sheet to a temperature sufficient to at least sinter portions of said toner image in the presence of an electric field between each said image member and said intermediate sheet of a direction urging the toner image being transferred to transfer to said smooth hard surface, overlaying the multicolor toner image with the receiving sheet, heating the multicolor toner image to at least its glass transition temperature, applying a force to said receiving sheet and intermediate sheet to create pressure sufficient to transfer the heated multicolor image to the receiving sheet while said sheets are moving at a first speed, allowing said sheets to cool while in contact and while said sheets am stopped or moving at a second speed slower than the first speed, and separating said sheets. - View Dependent Claims (32, 33, 34, 35)
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36. An image forming apparatus comprising:
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an image member, means for forming a series of electrostatic images on said image member, means for applying different color toners to said series of electrostatic images to form a series of different color single color toner images, a transfer drum, a supply for holding at least one discrete intermediate sheet, the intermediate sheet having an image receiving surface and leading and trailing edges, means for feeding an intermediate sheet from said intermediate sheet supply on to the periphery of said transfer drum, means for holding the intermediate sheet on the periphery of the transfer drum, means for rotating said transfer drum to bring the image receiving surface of the intermediate sheet repeatedly into transfer relation with the series of toner images on said image member, means for transferring the series of toner images in overlying registration to the receiving surface to form a multicolor image, means for positioning a receiving sheet on top of said multicolor toner image on said intermediate sheet, means for applying pressure to said sheets while raising or maintaining the temperature of said multicolor toner image to or above its glass transition temperature to transfer said multicolor toner image to said receiving sheet, means independent of said pressure applying means for transporting said sheets away from said pressure applying means sufficiently to allow said toner image to cool below its glass transition temperature, and means for separating said sheet after said toner image is cooled below said glass transition temperature.
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37. An image forming apparatus comprising:
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an image member, means for forming a series of different color toner images on said image member, a transfer member, a supply for holding at least one intermediate sheet, said intermediate sheet having an image receiving surface and leading and trailing edges, means for feeding an intermediate sheet from said intermediate supply onto said transfer member, means for holding the intermediate sheet on said transfer member, means for cycling said transfer member to bring the image receiving surface of the intermediate sheet repeatedly into transfer relation with toner images on said image member, means for transferring said toner images from said image members to said image receiving surface in overlying registration to form a multicolor image, means for positioning a receiving sheet on said multicolor image on said image receiving surface before said intermediate sheet is separated from said transfer member, means for applying pressure to said sheets while backed by said transfer member in the presence of sufficient heat to transfer said multicolor toner image to said receiving sheet, means for transporting said sheets away from said pressure applying means sufficiently to allow said toner image to cool below its glass transition temperature, and means for separating said sheets after said toner image has cooled below its glass transition temperature and for returning said intermediate sheet to said intermediate sheet supply. - View Dependent Claims (38, 39)
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Specification