C500,Grad and Bias of Dev very low

[neon]

Hi,

I have a HP9850MFP(same as C500 or 8050). with poor Cyan Density, and check the process Value with poor Grad and Bais of Dev, both of them are all equle to 200V

I have try to changed the developer, developer unit ,gamma senser and gamma senser board, drum unit , charging unit, 100Kpm and 200kpm,even rewrite the firmware, I think I have already done all that I can , but it is not any Improve.

when I restore the process adj value, the Cyan well be deep enough, but only do once autogamme , the grad value is fall down and color go light.

have any Recommendation? thanks

[mrwho]

Here's some troubleshooting procedures for light colors - see if it can possibly help you!

Light Density
[Symptom]
Density is too light in highlight area and solid area.
[Problem identification]
A: If all colors are light, go to Probable causes A-a and A-b.
B: If single color is light, go to Probable causes B-a, B-b and B-c.
[Probable causes]
A-a: After the gamma automatic adjustment, under the adjustment dispersion, the developer condition is fixed low and the density temporarily decreases.
(Go to Basic solutions A-a.)
A-b: As the second transfer condition is not appropriate, transfer failure occurs and the density decreases. (Go to Basic solutions A-b.)
B-a: Due to developer deterioration, developer charging level increases and the image density on the drum decreases. It tends to occur with 5% or lower coverage print. (Go to Basic solutions B-a through B-c.)
B-b: The density is low since the toner density is low. (Go to Basic solutions B-d.)
B-c: As the first transfer condition is not appropriate, transfer failure occurs and the density decreases. (Go to Basic solutions B-e.)

[Basic solutions]
A-a: To change the developing condition, perform the gamma auto adjustment again in the key operator mode, 21. Execute adjustment operation.
A-b: Perform the second transfer current adjustment. (For the procedure, see the separate sheet of 15. Paper Support.)
B-a: To resolve developer deterioration, perform the toner refresh mode in the key operator mode. (up to three times)
B-b: If it is not resolved by the manual toner refresh mode, output seven A3 solid pages from the 36 mode internal pattern in the affected color with customer’s consent.
B-c: If the key operator mode, 13. Memory switch, 49. Color gamut is set Normal, change it to Wide.
B-d: To check the toner density, perform the 47 mode 50-P12 through 15.
1) If the value is 180 or less, check the toner bottle rotation during printing.
2) If the bottle is not rotating, repair the toner supply unit.
If the value is more than 180, replace the developer.
B-e: Adjust the first transfer current in the 36 mode, 1. Process adjustment, 1. High voltage adjustment, 1. First transfer current adjustment within a range between -45 and -30μA. However, too large and too small values are both NG

[neon]

Thank you for so quickly reply, I well try it!




Here's some troubleshooting procedures for light colors - see if it can possibly help you!

Light Density
[Symptom]
Density is too light in highlight area and solid area.
[Problem identification]
A: If all colors are light, go to Probable causes A-a and A-b.
B: If single color is light, go to Probable causes B-a, B-b and B-c.
[Probable causes]
A-a: After the gamma automatic adjustment, under the adjustment dispersion, the developer condition is fixed low and the density temporarily decreases.
(Go to Basic solutions A-a.)
A-b: As the second transfer condition is not appropriate, transfer failure occurs and the density decreases. (Go to Basic solutions A-b.)
B-a: Due to developer deterioration, developer charging level increases and the image density on the drum decreases. It tends to occur with 5% or lower coverage print. (Go to Basic solutions B-a through B-c.)
B-b: The density is low since the toner density is low. (Go to Basic solutions B-d.)
B-c: As the first transfer condition is not appropriate, transfer failure occurs and the density decreases. (Go to Basic solutions B-e.)

[Basic solutions]
A-a: To change the developing condition, perform the gamma auto adjustment again in the key operator mode, 21. Execute adjustment operation.
A-b: Perform the second transfer current adjustment. (For the procedure, see the separate sheet of 15. Paper Support.)
B-a: To resolve developer deterioration, perform the toner refresh mode in the key operator mode. (up to three times)
B-b: If it is not resolved by the manual toner refresh mode, output seven A3 solid pages from the 36 mode internal pattern in the affected color with customer’s consent.
B-c: If the key operator mode, 13. Memory switch, 49. Color gamut is set Normal, change it to Wide.
B-d: To check the toner density, perform the 47 mode 50-P12 through 15.
1) If the value is 180 or less, check the toner bottle rotation during printing.
2) If the bottle is not rotating, repair the toner supply unit.
If the value is more than 180, replace the developer.
B-e: Adjust the first transfer current in the 36 mode, 1. Process adjustment, 1. High voltage adjustment, 1. First transfer current adjustment within a range between -45 and -30μA. However, too large and too small values are both NG