Image forming apparatus reducing media surface roughness before forming a color image protected by transparent toner

• US 10,452,004 B2
• Filed: 11/17/2017
• Issued: 10/22/2019
• Est. Priority Date: 11/21/2016
• Status: Active Grant

• Current Assignee: Oki Data Corporation (OKI Electric Industry Company Limited)
• Original Assignee: Oki Data Corporation (OKI Electric Industry Company Limited)
• Inventors: Takazawa, Takayuki
• Primary Examiner(s): Wong, Joseph S
• Application Number:
  US15/816,080
• Publication Number:
  US 20180143571A1
• Time in Patent Office: 704 Days
• CPC Class Codes: G03G 15/0131 for transferring a pattern to a second base
• CPC Class Codes: G03G 15/0189 primary transfer to an intermediate transfer belt G03G15/0184 takes precedence
• CPC Class Codes: G03G 15/1605 using at least one intermediate support G03G15/1625 takes precedence
• CPC Class Codes: G03G 15/1675 with means for controlling the bias applied in the transfer nip
• CPC Class Codes: G03G 15/1695 with means for preconditioning the paper base before the transfer
• CPC Class Codes: G03G 15/235 the image receiving member being preconditioned before transferring the second image, e.g. decurled, or the second image being formed with different operating parameters, e.g. a different fixing temperature
• CPC Class Codes: G03G 15/36 Editing, i.e. producing a composite image by copying one or more original images or parts thereof
• CPC Class Codes: G03G 15/6558 Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point
• CPC Class Codes: G03G 15/6579 Refeeding path for composite copying
• CPC Class Codes: G03G 15/6582 Special processing for irreversibly adding or changing the sheet copy material characteristics or its appearance, e.g. stamping, annotation printing, punching
• CPC Class Codes: G03G 15/6585 by using non-standard toners, e.g. transparent toner, gloss adding devices
• CPC Class Codes: G03G 15/6591 characterised by the recording material, e.g. plastic material, OHP, ceramics, tiles, textiles details transferring the toner pattern onto particular materials G03G15/1625
• CPC Class Codes: G03G 2215/0129 horizontal medium transport path at the secondary transfer

Abstract

An image forming apparatus includes an image forming section and a transfer section. The image forming section includes a first image forming unit that forms a first developer image and a second image forming unit that forms a second developer image. The transfer section transfers, on a basis of a first transfer condition, the first developer image onto a medium, and transfers, on a basis of a second transfer condition, the second developer image onto the medium onto which the first developer image has been transferred. The second transfer condition is different from the first transfer condition.

Claims

1. An image forming apparatus comprising:

an image forming section that performs a first image forming operation and a second image forming operation, the first image forming operation forming a first developer image, the second image forming operation sequentially forming a second developer image and a third developer image after the first image forming operation has been performed, the first developer image being a first transparent image or a white image, the second developer image being a colored image, the third developer image being a second transparent image; and

a transfer section that performs a first transfer operation at a first transfer voltage and a second transfer operation at a second transfer voltage, the first transfer operation transferring the first developer image onto a medium before the image forming section performs the second image forming operation, the second transfer operation transferring the second developer image and the third developer image onto the first developer image having been transferred onto the medium to allow the second developer image and the third developer image to be stacked in this order on the first developer image having been transferred onto the medium, an absolute value of the first transfer voltage is higher than an absolute value of the second transfer voltage.

2. The image forming apparatus according to claim 1, wherein

the transfer section includes

a primary transfer section that performs first primary transfer and second primary transfer, the first primary transfer transferring the first developer image onto an intermediate transfer member, the second primary transfer transferring the second developer image and the third developer image onto the intermediate transfer member, and

a secondary transfer section that performs first secondary transfer and second secondary transfer, the first secondary transfer transferring, onto the medium, the first developer image that has been transferred onto the intermediate transfer member, the second secondary transfer transferring, onto the first developer image that has been transferred onto the medium, the second developer image and the third developer image that have been transferred onto the intermediate transfer member.

3. The image forming apparatus according to claim 1, wherein

the transfer section performs the first transfer operation at first current density and performs the second transfer operation at second current density, and

the first current density is greater than the second current density.

4. The image forming apparatus according to claim 1, wherein

the medium has a surface including a protrusion and a depression, and

transfer efficiency at the protrusion is lower than transfer efficiency at the depression in the first transfer operation.

5. The image forming apparatus according to claim 1, wherein

the colored image is at least one of a yellow toner image, a magenta toner image, and a cyan toner image.

6. The image forming apparatus according to claim 1, wherein

the transfer section is configured to sequentially perform the first transfer operation and the second transfer operation on the the same medium.

7. The image forming apparatus according to claim 1, wherein

the transfer section is configured to perform the second transfer operation so as to transfer the second developer image and the third developer image onto the first developer image fixed to the medium.

8. An image forming method including:

performing a first image forming operation that forms a first developer image being a first transparent image or a white image,

performing a second image forming operation that sequentially forms a second developer image and a third developer image, the second developer image being a colored image, the third developer image being a second transparent image,

performing a first transfer operation at a first transfer voltage that transfers the first developer image onto a medium before the image forming section performs the second image forming operation; and

performing a second transfer operation at a second transfer voltage that transfers the second developer image and the third developer image onto the first developer image having been transferred onto the medium to allow the second developer image and the third developer image to be stacked in this order on the first developer image having been transferred onto the medium, an absolute value of the first transfer voltage is higher than an absolute value of the second transfer voltage.