technical notice

7/18/2019 Technical Notice

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Subject: bizhub C250/C300/C352

TCR Sensor detected Abnormal Low Toner Density (C2557/ 55/ 53/ 51)

<Symptom>

At an early stage of using Toner Cartridge, Trouble Code C-255x (K: 2557, Y: 2555, M: 2553, C: 2551)

is displayed because the toner is not replenished properly from the Toner Cartridge to the Imaging Unit.

<Cause>

(1) Part of Film Shutter blocks the toner replenishment entrance.

(2) Toner Cartridge is not set properly.

• Sum-up on Corrective Action by cause

(1) Part of Film Shutter blocks the toner replenishment entrance.

Details of symptom：

Toner is not supplied properly because a part of film shutter remains at the toner replenishment

entrance of Toner Cartridge and it blocks the toner replenishment. (Refer to the picture below.)

Consequently the TCR Sensor detects the abnormal toner density and then it shows Trouble Code

C255x (K:2557, Y:2555, M:2553, C:2551) .

Detail o f Cause：

The adhesive strength film to the shutter became too strong due to the change of pressure of

adhesive machine that glue the film by applying the supersonic waves. Therefore, when the film

shutter is opened, the film is broken and the remained film at the entrance blocks the toner

replenishment.

<Countermeasure>

The following actions are taken since production in Feburary ’06 (Lot：6206xxxx and onwards）

1. Decrease tangent pressure of adhesive machine against the object.

2. Adjust with Carbon paper in order to evenly fit between object and adhesive machine.

3. Check the adhesive condition by peeling the film (3 times a day).

After taking all actions mentioned above, the validity of all actions were confirmed by testing under

several conditions.

The remained film is blocking the

toner shutter replenishmententrance.



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Remained Film

Non-blocked Area

＜Occurrence Ratio＞

It assumes that the problem occurrence ratio is0.5% or less.

It has been confirmed that the problem does not occurdepending on the condifiton even if the Shutter Filmtears. If the percentage of the non-blocked area ofToner Replenishment Entrance is 30% or more, thetoner is replenished properly.

(2) Toner Cartri dge is not set properly.

Details of symptom：

There is a possibility that the Toner Cartridge is not locked completely even if the Front Door is

closed. Due to that the coupling gear for the drive of toner replenishment does not rotate. As the

result the toner is not replenished and the trouble code C255x is displayed.

<Half lock condition> <Normal lock

condition>

<Investigative Results>

It is estimated that the Black Toner Cartridge has a higher possibility of causing this problem than the

others because the Black Toner Cartridge is wider and the locking part is shifted to the right side.

The other Cartridges have lower possibility because the locking part is located in the middle.

<Countermeasure>

Now it is under consideration to improve the locking mechanism.

Please advice the customer when replacing the Toner Cartridge; make sure that the Toner Cartridge

is set properly. Please advice them to push it until hearing the click sound.

<Action in field>

As preventive action,

Check film for TC Shutter part of all color TC during the set-up of the machine.

>Check film for the previous number from Lot No.6206xxxx

Coupling Gear (TC)

Coupling Gear (Main Unit)

Coupling Gear (TC)

Coupling Gear (Main Unit)



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Check locking condition for all color TC (Push the cartridge until hearing the click sound.)

For the current machine in the fileld, take a action respectively when occurring problem.

>At this time, almost all the problem occurred on the Black Toner Cartridge (Lot：5Y06xxxx) and

only Cyan Toner Cartridges that has not been occurred the problem were produced. Accordingly,it is supposed that the number of problem will be reduced from now on.

For Check procedure, please see next page.

>Procedure on Set up, TC replacement and Problem occurrence

Procedure is described on TC failure and Film ripping check.）

<Toner Cartridge Set-up/Replacement Procedure >

1. After finishing all set-up procedure pull out the cartridge and check the condition of shutter by

referring to the picture below.

2. If NG, set Toner Cartridge in Main Body with closing shutter after perfectly removing film of TC

Shutter part.

3. If OK, set Toner Cartridge in Main Body with closing shutter

4. Check the TCR-x value after completing Image Stabilization.

*Service Choice-> State Confirmation-> Level History 1-> Do check TCR-x value

5. If the value of TCR-x is indicating approx. 7% , complete it with judging no problem,

6. If not reaching 7％, check TCR-x value after repeating Toner supply two or three times.

*Service Choice-> Image Process Adjustment-> TCR Toner Supply-> Do applicable Toner Supply

7. If the TCR-x value does not change after proceeding above actions, take off and put on or replace

the Toner Cartridge or Imaging Unit.

<Procedure on occurring Problem in the current Machine in the field >

1. If trouble code C-2557（C2551/3/5）appears on the display or the Image becomes lighter, remove

the applicable Toner Cartridge indicated by the trouble code.2. Check film condition of TC Shutter part. (For OK/NG judgment, see the above picture)3. If misdoubting accuracy of Toner Supply, be sure to check on whether the part of film exists or not

by using pen point.4. If NG, set TC in Main Body with closing shutter after perfectly removing film of TC Shutter part.5. If OK, set TC in Main Body with closing shutter (Regardless of OK/NG, check as below)6. Keep TCR-x value in mind.

*Service Choice-> State Confirmation-> Level History 1-> Do check TCR-x value

NGSupply hole is stuffed by film.

OKFilm is perfectly removed.



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7. Implement Toner Supply*Service Choice-> Image Process Adjustment-> TCR Toner Supply-> Do supply applicable toner

8. If rising TCR-x value remembered by you, complete it with judging OK (measure: about 7%)9. If not rising, check TCR-x value after repeating Toner supply two or three times.

10. If the TCR-x value does not change after proceeding above actions, take off and put on or replace

the Toner Cartridge or Imaging Unit.

In this case, check on whether

film exists or not by pen point.

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