Image forming apparatus

• US 20050244203A1
• Filed: 04/22/2005
• Published: 11/03/2005
• Est. Priority Date: 04/28/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kamiyama, Nobuto
• Granted Patent: US 7,356,300 B2
• Time in Patent Office: Days
• US Class Current: 399/341
• CPC Class Codes: G03G 15/20 for fixing, e.g. by using heat

Abstract

A temperature of a sheet material after passing a first fixing device and before entering a second fixing device changes between the start and the end of an image forming job, thus resulting in a change in the gloss of the toner image.

A cooling apparatus for directly or indirectly cooling the sheet material is provided in a conveying path 25 between the first fixing device 10 and the second fixing device 20 thereby suppressing a change in the image gloss between the start and the end of the image forming job.

Claims

1. An image forming apparatus comprising:

image forming means which forms a toner image on a recording material;

first image heating means which heats the toner image on the recording material;

second image heating means which heats the toner image on the recording material, heated by the first image heating means;

conveying means which conveys the recording material, heated in the first image heating means, to the second image heating means; and

cooling means which cools the recording material, heated in the first image heating means, before reaching the second image heating means.

2. An image forming apparatus according to claim 1, wherein the cooling means includes air-cooling means.

3. An image forming apparatus according to claim 2, wherein the air-cooling means blows air to the conveying means.

4. An image forming apparatus according to claim 3, wherein the conveying means includes a guide plate for guiding conveying of the recording material, and the guide plate is provided with a through hole for passing the air from the air-cooling means for guiding to the recording material.

5. An image forming apparatus according to claim 4, wherein the through hole is formed as a slit along a direction inclined to a conveying direction of the recording material.

6. An image forming apparatus according to claim 4, wherein the guide plate is provided, within a conveying path of the recording material by the conveying means, at an upstream side in the conveying direction of the recording material.

7. An image forming apparatus according to claim 2, wherein the air-cooling means includes a fan and a duct for guiding the air from the fan to a cooling portion.

8. An image forming apparatus according to claim 1, wherein the cooling means executes cooling of the recording material, within the conveying path of the recording material by the conveying means, at an upstream side in the conveying direction of the recording material.

9. An image forming apparatus according to claim 1, further comprising control means which, in case of forming images continuously on plural recording materials utilizing the first image heating means and the second image heating means, controls an operation of the cooling means so as to maintain a temperature of the recording material immediately before entering the second image heating means within a predetermined temperature range.

10. An image forming apparatus according to claim 9, wherein the control means activates the cooling means when image formations are executed on a predetermined number of recording materials.

11. An image forming apparatus according to claim 9, wherein the control means varies a timing of activating the cooling means according to a type of the recording material.

12. An image forming apparatus comprising:

image forming means which forms a toner image on a recording material;

first image heating means which heats the toner image on the recording material;

second image heating means which heats the toner image on the recording material, heated by the first image heating means;

conveying means which conveys the recording material, heated in the first image heating means, to the second image heating means; and

control means which controls a temperature of the recording material, after a heating process in the first image heating means and prior to a heating process in the second image heating means.

13. An image forming apparatus according to claim 12, further comprising cooling means which cools the recording material, heated by the first image heating means, before reaching the second image heating means, wherein the control means controls an operation of the cooling means.

14. An image forming apparatus according to claim 13, further comprising a temperature detecting element for detecting a temperature of the conveying means, wherein the control means controls an operation of cooling the conveying means by the cooling means, based on an output of the temperature detecting element.

15. An image forming apparatus comprising:

image forming means which forms a toner image on a recording material;

first image heating means which heats the toner image on the recording material;

second image heating means which heats the toner image on the recording material, heated by the first image heating means;

conveying means which conveys the recording material, heated in the first image heating means, to the second image heating means; and

heating means which heats the recording material, heated in the first image heating means, before reaching the second image heating means.

16. An image forming apparatus according to claim 15, wherein the heating means heats the conveying means.

17. An image forming apparatus according to claim 16, wherein the heating means executes heating by warm air.

18. An image forming apparatus comprising:

image forming means which forms a toner image on a recording material;

first fixing means which fixes the toner image on the recording material;

second fixing means which fixes the toner image on the recording material, fixed by the first fixing means;

conveying means which conveys the recording material, fixed in the first fixing means, to the second fixing means; and

cooling means which cools the recording material, fixed in the first fixing means, before reaching the second fixing means.

19. An image forming apparatus comprising:

image forming means which forms a toner image on a recording material;

first fixing means which fixes the toner image on the recording material;

second fixing means which fixes the toner image on the recording material, fixed by the first fixing means;

conveying means which conveys the recording material, fixed in the first fixing means, to the second fixing means; and

control means which controls a temperature of the recording material, after a fixing process in the first fixing means and prior to a fixing process in the second fixing means.

20. An image forming apparatus comprising:

image forming means which forms a toner image on a recording material;

first fixing means which fixes the toner image on the recording material;

second fixing means which fixes the toner image on the recording material, fixed by the first fixing means;

conveying means which conveys the recording material, fixed in the first fixing means, to the second fixing means; and

heating means which heats the recording material, fixed in the first fixing means, before reaching the second fixing means.