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User GuidePro C7500/C7500H

Black Spots (Granular Toner Clotting)

Paper is stained with toner spots of 0.5–1 mm (0.02–0.04 inches) in diameter.

illustration of Paper is Spotted with Toner

Cause:

This is caused by toner slipping through the cleaning web and adhering to the paper.

Occurrence conditions:

  • Duplex printing

  • Printing on uncoated (especially rough-textured) paper

  • Halftone printing

  • Printing after halftone printing

  • Printing after printing on many small-size sheets

Solution:

1If the paper is not registered as custom paper, register the brand of the paper.

2In [Detailed settings] for the custom paper you are using, select 1232: [Fusing Temperature], and then increase the value in the following corresponding settings by 5°C.

  • 1232-01: Fusing Temperature: BW/FC/FCS: Heat Roller Temp

  • 1232-06: Fusing Temperature: FCS: Heat Roller Temp: Clear/Special

  • 1232-07: Fusing Temperature: FCS: Heat Roller Temp: White

  • 1232-08: Fusing Temperature: FCS: Heat Roller Temp: Metallic

  • 1232-26: Fusing Temperature: S: Heat Roller Temp: Clear/Special

  • 1232-27: Fusing Temperature: S: Heat Roller Temp: White

  • 1232-28: Fusing Temperature: S: Heat Roller Temp: Metallic

  • 1232-46: Fusing Temperature: BW/FC/FCS: Fuser Setting HQ: Heat Roller Temp

  • 1232-51: Fusing Temperature: FCS: Fuser Setting HQ: Heat Roller Temp: Clear/Special

  • 1232-52: Fusing Temperature: FCS: Fuser Setting HQ: Heat Roller Temp: White

  • 1232-53: Fusing Temperature: FCS: Fuser Setting HQ: Heat Roller Temp: Metallic

  • 1232-71: Fusing Temperature: S: Fuser Setting HQ: Heat Roller Temp: Clear/Special

  • 1232-72: Fusing Temperature: S: Fuser Setting HQ: Heat Roller Temp: White

  • 1232-73: Fusing Temperature: S: Fuser Setting HQ: Heat Roller Temp: Metallic

3Print the image. Has the problem been resolved?

Print 20 sheets of the image, then another 10.

Yes

Finished!

No

Go to the next step.

4Increase the heating roller’s temperature by 5°C.

5Print the image. Has the problem been resolved?

Print 20 sheets of the image, then another 10.

Yes

Finished!

No

Repeat Steps 4 and 5. If the problem persists even after increasing the heating roller's temperature to 185°C.

Note

  • If glossy streaks become noticeable or a paper jam occurs in the fusing unit due to increasing the fusing heat roller's temperature, reset the temperature setting to the default value, and then go to the next step.

6In [Detailed settings] for the custom paper you are using, select 1231: [Print Speed], and then set the value in the following corresponding settings to [Middle].

  • 1231-01: Print Speed: BW/FC/FCS: BW/FC/FCS

  • 1231-02: Print Speed: FCS: Clear/Special

  • 1231-03: Print Speed: FCS: White

  • 1231-04: Print Speed: FCS: Metallic

  • 1231-06: Print Speed: S: Clear/Special

  • 1231-07: Print Speed: S: White

  • 1231-08: Print Speed: S: Metallic

  • 1231-10: Print Speed: BW/FC/FCS: Fuser Setting HQ: BW/FC/FCS

  • 1231-11: Print Speed: FCS: Fuser Setting HQ: Clear/Special

  • 1231-12: Print Speed: FCS: Fuser Setting HQ: White

  • 1231-13: Print Speed: FCS: Fuser Setting HQ: Metallic

  • 1231-15: Print Speed: S: Fuser Setting HQ: Clear/Special

  • 1231-16: Print Speed: S: Fuser Setting HQ: White

  • 1231-17: Print Speed: S: Fuser Setting HQ: Metallic

7Print the image. Has the problem been resolved?

Print 20 sheets of the image, then another 10.

Yes

Finished!

No

Go to the next step.

8Print speed is [Middle], lower it to [Low].

9Print the image. Has the problem been resolved?

Print 20 sheets of the image, then another 10.

Yes

Finished!

No

Go to the next step.

Note

  • If a paper jam occurs in the fusing unit due to a decrease in the print speed, reset the print speed to the default value, and then go to the next step.

10In [Detailed settings] for custom paper, increase the value in 1238: [Fusing Cleaning] by one step.

  • 1238-01: Fusing Cleaning: BW/FC/FCS: Cleaning Interval: BW/FC/FCS

  • 1238-02: Fusing Cleaning: FCS/S: Cleaning Interval: Clear/Special

  • 1238-03: Fusing Cleaning: FCS/S: Cleaning Interval: White

  • 1238-04: Fusing Cleaning: FCS/S: Cleaning Interval: Metallic

11Print the image. Has the problem been resolved?

Print 20 sheets of the image, then another 10.

Yes

Finished!

No

Repeat Steps 10 and 11.

If the problem persists, there is no other solution.

Note

  • Select "Clear/Special" when using Neon Yellow, Neon Pink, or Invisible Red. Select "Metallic" when using Gold or Silver.

  • Increasing the frequency of cleaning will shorten the replacement cycle of the fuser cleaning unit.

  • After performing the solution, it is recommended to perform the color calibration of the external printer controller.