Image forming apparatus and fixing device
An image forming apparatus has a conveying element for conveying a sheet, an image forming section for forming an image on the sheet with liquid developer, and a fixing device including a rubbing mechanism for rubbing the image on the sheet. A fixing device has a rubbing mechanism for rubbing an image which is formed with liquid developer.
1. An image forming apparatus for forming an image, comprising:
a conveying element configured to convey a sheet;
an image forming section configured to form the image on the sheet with liquid developer; and
a fixing device configured to fix the image onto the sheet,
wherein the fixing device includes a rubbing mechanism configured to rub the image on the sheet,
the liquid developer includes colored particles for coloring the image, carrier liquid in which the colored particles are dispersed, and polymer compounds dissolved or swollen in the carrier liquid, and
the polymer compounds cover the colored particles on the sheet.
2. The image forming apparatus according to claim 1 , wherein
the conveying element conveys the sheet in a first direction at a first speed,
the fixing device includes a drive mechanism configured to operate the rubbing mechanism,
the rubbing mechanism includes a contact surface which contacts the image on the sheet, and
the drive mechanism moves the contact surface relative to the sheet.
3. The image forming apparatus according to claim 2 , wherein
the rubbing mechanism includes an upstream rubbing mechanism and a downstream rubbing mechanism configured to rub the image after the upstream rubbing mechanism.
4. The image forming apparatus according to claim 2 , wherein
the conveying element includes a conveying belt configured to convey the sheet, and a backup roller configured to push the conveying belt against the rubbing mechanism, and
the sheet passes between the conveying belt and the contact surface.
5. The image forming apparatus according to claim 2 , wherein
the drive mechanism includes a drive source which reciprocates the contact surface in a first traverse direction traversing with the first direction and a second traverse direction opposite to the first traverse direction,
the rubbing mechanism includes a contact cylinder configured to rub the sheet, a shaft configured to support the rotatable contact cylinder, and a cam element configured to press the shaft in the first traverse direction, and
the drive source rotates the cam element.
6. The image forming apparatus according to claim 3 , wherein
the upstream rubbing mechanism fixes the image onto the sheet at a fixation ratio different from the downstream rubbing mechanism.
7. The image forming apparatus according to claim 4 , wherein
the rubbing mechanism includes a rubbing belt configured to rub the image on the sheet.
8. The image forming apparatus according to claim 7 , wherein
the drive mechanism includes:
an unwinder configured to unwind the rubbing belt;
a winder configured to wind the rubbing belt; and
a first press mechanism configured to press the rubbing belt to the image between the unwinder and the winder.
9. The image forming apparatus according to claim 8 , wherein
the winder stops while the conveying belt conveys the sheet, and the winder winds the rubbing belt while the conveying belt is stopped.
10. The image forming apparatus according to claim 8 , wherein
the sheet includes a preceding sheet and a subsequent sheet conveyed after the preceding sheet,
the first press mechanism includes:
a press piece configured to press the rubbing belt to the image;
a biasing element configured to bias the press piece toward the image; and
a separator configured to separate the press piece from the rubbing belt, and
the separator separates the press piece from the rubbing belt from when the preceding sheet passes between the rubbing and conveying belts to when the subsequent sheet passes between the rubbing and conveying belts.
11. The image forming apparatus according to claim 8 , wherein
the first press mechanism includes:
a press piece configured to press the rubbing belt to the image;
a biasing element configured to bias the press piece toward the image;
a separator configured to separate the press piece from the rubbing belt; and
an intermediate piece configured to separate the rubbing belt from the conveying belt between the unwinder and the winder, and
the press piece includes an upstream press piece configured to press the rubbing belt to the image before the sheet passes between the intermediate piece and the conveying belt, and a downstream press piece configured to press the rubbing belt to the image after the sheet passes between the intermediate piece and the conveying belt.
12. The image forming apparatus according to claim 8 , further comprising
a nip element configured to form a nip portion for holding the sheet on the conveying belt in cooperation with the backup roller extending in a traverse direction traversing with the first direction, wherein
a rubbing position where the rubbing belt rubs the sheet and the nip portion are aligned in the traverse direction.
13. The image forming apparatus according to claim 2 , wherein
the rubbing mechanism includes a rubbing loop configured to rub the image, and
the drive mechanism includes a revolving mechanism configured to revolve the rubbing loop.
14. The image forming apparatus according to claim 2 , wherein
the sheet includes a formation surface on which the image is formed, and
the contact surface includes a rotation surface which rotates around a rotation axis extending in a direction intersecting with the formation surface.
15. The image forming apparatus according to claim 14 , wherein
the rotation surface includes a first rotation surface rotating in a first rotation direction, and a second rotation surface rotating in a second rotation direction opposite to the first rotation direction, and
the first and second rotation surfaces are aligned in a traverse direction traversing with the first direction.
16. The image forming apparatus according to claim 14 , further comprising:
an adjustment mechanism configured to adjust a size of a contact region between the formation and contact surfaces in response to a thickness of the sheet.
17. The image forming apparatus according to claim 2 , wherein
the rubbing mechanism includes a contact surface which contacts the image on the sheet, and
the drive mechanism includes a vibration motor configured to vibrate the contact surface.
18. The image forming apparatus according to claim 2 , wherein
the contact surface includes a surface at least partially covered with a nonwoven fabric.
19. The image forming apparatus according to claim 1 ,
wherein the fixing device is configured for non-thermally fixing the image on the sheet.
20. A fixing device, comprising a rubbing mechanism for rubbing an image which is formed with liquid developer, wherein
the liquid developer includes colored particles for coloring the image, carrier liquid in which the colored particles are dispersed, and polymer compounds dissolved or swollen in the carrier liquid, and
the polymer compounds cover the colored particles on the sheet.