Utax CLP 3721 Service manual

1/1
Technical Bulletin
UTAX
UTAX
CLP 3721
CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 01 / Note for the toner installation error 2KW-B081/M
Date: 18-03-2011
T OPIC :
Following error message may appear when installing the new toner container. This may be corrected as below.
M ESSAGE DISPLAYED :
MFP : “The toner container is improperly installed” Printer : “Check the toner container”
C ORRECTIVE ACTION :
Once take out the toner container from the machine. Rotate
the coupling at the right side of the toner container clockwise
to eliminate the gap between the hook of the coupling and the
latch. Then, reinstall it in the machine.
Classification:
Entire Stock Rework
In-Field modification at next visit
X
In-Field modification by case
No modification necessary
Field Measure:
Please check the above and act correctively.
Serial Nos.:
n/a
Toner container
Latch
Hook of coupling
Eliminate the gap
Rotate the coupling CW
to eliminate the gap
Error message may appear
Coupling
Coupling
Enlarged view of section

1/2
Technical Bulletin
UTAX
UTAX
CLP 3721
CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 02 / Firmware Upgrade (MAIN 02.005 / ENG. 03.003) 2KV-B085/M
Date: 18-04-2011
T OPIC :
The firmware is upgraded as follows.
C ONTENT OF CHANGES :
Garbled characters.
Characters in the maintenance report may be garbled. - Therefore, this is corrected.
Error occurring with a certain PCL data.
F24B error appears when sending a certain PCL date while setting BW mode. - Therefore, this is corrected.
T7toner disposal control prolongs too long.
T7 toner disposal control prolongs too long until color calibration is executed when turning power on with 50 degree C or more of fusing
temperature. - Therefore, this is corrected.
Measure against failure at initial toner install mode.
Number of the initial drum refresh out of box is recorded in the EEPROM. The number is counted up at every drum refresh. Remaining
numbers of drum refresh are executed when resuming.
Change of toner disposal at initial machine aging out of box.
Toner disposal at drum refresh is changed from twice to once to reduce amount of toner disposed at drum refresh. Drum refresh,
however, is executed twice while tone is not disposed in the 2nd time.
Amount of toner disposal is reduced by half the amount. While the aging time remains unchanged.
Adding auto color registration adjustment timing.
Auto color registration adjustment is performed at the print 3 hours or more after the last print job.
DDNS cannot be registered.
DDNS cannot be registered In DHCP. - Therefore, this is corrected.
Measure against Kerberos authentication failure.
Kerberos authentication from MFP may fail when the expiry date for use of the user account approaches. - Therefore, this is corrected.
C/M/Y coverage does not become 0.
C/M/Y coverage does not become 0 with pure black data not being composite black. - Therefore, this is corrected.
Logo mark area is filled in black.
Logo mark area is filled in black when printing with an application named Formtastic.
Measures against error with a certain file.
CF248 error appears with a certain user file. - Therefore, this is corrected.
Characters garble with a certain CAD file.
Characters partially garble with a certain CAD file according to output size. - Therefore, this is corrected.
Umlaut font failure with PDF data.
Umlaut fonts are not partially printed with PDF data using Adobe Reader/Acrobat (9.2.0) + PCL-XL driver (KX v5.0.1930). - Therefore, this
is corrected
Code39 barcode print failure with a certain file.
Code39 barcode is not printed but printed as text. - Therefore, this is corrected.
Image failure printing backside Image with a certain file.
Leading edge of the image may shift or the image at the center may be dropped out when printing the backside image of the certain file in
duplex mode. - Therefore, this is corrected.
Failure of undesired lines with a certain file.
Undesired lines may be printed when continuously printing certain 2 files. - Therefore, this is corrected.
Print failure with the data including a certain Prescribe command (corrected).
Preventing the data at the left edge from dropping out when outputting the PS data.
Data at the left edge may be dropped out and the character pitch may be broadened when outputting PS data. - Therefore, this is
corrected.

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Print failure when printing a certain file with KPDL(AUTO).
A certain file may not be printed with KPDL (AUTO). - Therefore, this is corrected.
Failure with a certain PS data.
Image may not be partly printed when outputting a certain PS data. - Therefore, this is corrected.
PS error when printing a certain data.
PS error may appear and print may be terminated when printing a certain data from Unix. - Therefore, this is corrected.
TIF image failure when printing the data containing TIF image.
TIF image may be printed in twice of the size when printing the data containing TIF image. - Therefore, this is corrected.
Character drop-out with a certain file.
Characters line may drop out with a certain file. - Therefore, this is corrected.
Measure against white spots around the characters with a certain file.
White spots may appear around the outline characters with a certain data. - Therefore, this is corrected.
Problem when printing with a certain macro.
The characters may be partly overlapped when printing with a certain macro. - Therefore, this is corrected.
Improving performance of outputting a certain data.
Performance is improved because it was pointed out that outputting a certain file from the special application is slow compared with output
from other models.
Measure against problem when outputting a certain PDF data.
Print out of a certain PDF data may be interrupted, and it may be stopped at the state of waiting print. - Therefore, this is corrected.
Preventing command from printed as text in the print data.
Command may be printed as text. - Therefore, this is corrected.
Measure against lock-up with a certain macro data.
When calling a certain macro data, the system may lock up while showing "Processing". - Therefore, this is corrected.
Print position shifting with a certain file.
Print position may shift with a certain file. - Therefore, this is corrected.
Failure when printing a certain file in duplex.
Upper part image of the 2nd side is not printed when printing a certain file in duplex.
Measure against problem when outputting a certain PDF data.
Error* may appear when directly printing a certain PDF data. - Therefore, this is corrected.
* System error, Processing lock-up and F030 error, etc.
F000 error with a certain PS data.
F000 error appears with a certain PS data. - Therefore, this is corrected.
Character drop-out with a certain PCL data.
Characters drop out with a certain PCL data. - Therefore, this is corrected.
Measure against output failure with Big5 font.
Big 5 font may not be printed out. - Therefore, this is corrected.
Measure against garbled characters with a certain file containing PJL.
FIRMWARE
Program No. Ver. Remarks
MAIN 2KV_3F00.002.005 002.005 New (CLP 3721, CLP 3726 / CLP 4721, CLP 4726)
ENGINE 2KT_1000.003.003 003.003 New (CLP 3721 / CLP 4721)
ENGINE 2KV_1000.003.003 003.003 New (CLP 3726 / CLP 4726)
Classification:
Entire Stock Rework
In-Field modification at next visit
X
In-Field modification by case
No modification necessary
Field Measure:
Please upgrade the firmware when the phenomena arise.
Serial Nos.:
CLP 3721 / CLP 4721
CLP 3726 / CLP 4726
Planned in March 2011 production

1/3
Technical Bulletin
UTAX
UTAX
CLP 3721
CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 03 / Colour background after setup NPresson/M
Date: 17-05-2011
T OPIC :
Colour background after setup.
C ORRECTIVE ACTION :
Check the contact springs of the drum units.
1 Open the top cover and 2 Slide the container guide and 3 Open the RFID holder.
remove the toner containers. remove it.
4 Slide the shutter and remove 5 Remove the transfer unit. 6 Remove the drum units.
the screw.
remove
Sample

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7 Remove the developing units. 8 Remove the right cover and the >HIGH VOLTAGE PWB<.
9 Check the resistor from the drum contacts.
10 Resistor > 1 Ohm set the correct position of the drum springs.
HIGH VOLTAGE PWB
Figure right side
Figure inner side
CYAN
BLACK
MAGENTA
YELLOW
Ω
Ω
Ω
Ω
right side
inner side
The resistor between the contact springs
(red) must be < 1 Ohm.
wrong
OK

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Classification:
Entire Stock Rework
In-Field modification at next visit
X
In-Field modification by case
No modification necessary
Field Measure:
Please check the above and act correctively.
Serial Nos.:
n/a

1/2
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 04 / Corrective measures for C0150 error with… 2KT-B120/M
Date: 30-05-2011
T OPIC :
C0150 error may appear with the wire (EXIT-ENGN) pinched by the rib on COVER TOP P. Therefore, the following are
changed.
[C0150: Backup memory read/write error (engine PWB)]
C ONTENT OF CHANGES :
A clamp (ACCESS CLAMP (No.1)) is added to the wire (EXIT-ENGN) to attach it.
Clamp added
No. Old Part
No.
New Part
No. Description Q’ty Compatibility Remarks
Old New Old New
1 -------- YZ112220 ACCESS CLAMP - 1 - O
STAY REAR TOP
COVER TOP P
A
Hole of STAY
B
The edge of the hole of the STAY
A 1mm or more gap with the edge of the CLAMP
B The wire should not get over the dotted line
ACCESSS CLAMP
(No.1)
Where to affix
ACCESSS.CLAMP
Enlarged
view of A
2mm 0mm
1mm gap
or more
The wire should not get over
the arrow mark side
ACCESSS CLAMP
(
No.1
)

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Classification: Entire Stock Rework
In-Field modification at next visit
X In-Field modification by case
No modification necessary
Field Measure: Please take good care when attaching the clamp to avoid the wire pinch when attaching COVER
TOP P.


Serial Nos.: CLP 3721 - CLP 4721
CLP 3726 - CLP 4726

From available timing in April 2011 production on.

1/2
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 05 / Corrective measures for the color dot images 2KV-B215/M
Date: 19-07-2011
T OPIC :
The drum change and firmware upgrade.
C ONTENT OF CHANGES :
1. Change of the drum unit
The color dot image may appear and the treatment for the
drum photo-conductive layer is changed as the corrective
measures. (Refer to the image sample)
2. Firmware upgrade
 Corrective measures for the color dot image.
A weak main charge is impressed during “Adding toner”in the drum protective environment.
A weak main charge is impressed during the start-up aging out of box.
 Corrective measures for the band image on the drum.
A band image is formed in between the color calibration and color registration adjustment. Therefore, this is corrected.
 Drum refresh mode supported
FIRMWARE
Program No. Ver. Remarks
MAIN 2KV_3F00.002.005 002.005 (all) CLP 3721, CLP 3726 / CLP 4721, CLP 4726
ENGINE 2KT_1000.004.003 004.003 New only CLP 3721 / CLP 4721
ENGINE 2KV_1000.004.003 004.003 New only CLP 3726 / CLP 4726
No. Old Part
No.
New Part
No. Description Q’ty Compatibility Remarks
Old New Old New
1 2KV93013 2KV93014 DK-590 1 1 X O only CLP 3726 / CLP 4726
2 2KT93013 2KT93014 DK-591 1 1 X O only CLP 3721 / CLP 4721
発生画像発生画像
Color dot
Sample image

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Classification: Entire Stock Rework
In-Field modification at next visit
X In-Field modification by case
No modification necessary
Field Measure: Please replace with the new type unit when the problem arises.
Please upgrade the engine firmware together with replacing with the new unit.


Serial Nos.: CLP 3721 - CLP 4721
CLP 3726 - CLP 4726

From available timing in June 2011 production.

1/1
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
T
A
TA
CLP 4721
CLP 4726
TB 06 / Correcting Parts List - >HOOK DU RELEASE< 2KW-B234/M
Date: 02-08-2011
T OPIC :
The parts number of the HOOK DU RELEASE (No.1) is registered.
No. Old Part
No.
New Part
No. Description Q’ty Compatibility SP Remarks
Old New Old New
1 ------------ 2KV29101 HOOK DU RELEASE - 1 - O -
Classification: Entire Stock Rework
In-Field modification at next visit
In-Field modification by case
X No modification necessary
Field Measure: Service information only


Serial No.:
FIG. 5 PAPER CONVEYING SECTION
Conveying Unit Rear Cover Unit
No.1 (HOOK DU RELEASE)

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Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
T
A
TA
CLP 4721
CLP 4726
TB 07 / Note when adjusting the color registration 2KW-B326/M
Date: 11-10-2011
T OPIC :
Please perform the following when adjusting the color registration.
When the color registration shift appears:
Perform [Calibration] (auto adjustment)
Manually adjust the color registration if [Calibration] (auto adjustment) cannot correct it.
P ROCEDURES :
1.) Perform the color calibration from the operation panel. (Calibration may be performed at power-up)
Menu  Adjustment/Maintenance  Calibration  OK  Calibration?  OK .
2.) Then, if necessary, manually perform the color registration adjustment (Details)
Menu  Adjustment/Maintenance  Registration (Details)  Print Chart  OK  Print Chart?  OK .
Check the printed chart to input the adjustment value for each color.
N OTE :
Don’t manually adjust the color registration first. The color registration is then adjusted but the color registration shift may
again appear after several days.
Perform the color registration adjustment (Details) on its basis for more accuracy.
Classification: Entire Stock Rework
In-Field modification at next visit
In-Field modification by case
X No modification necessary
Field Measure: No problem is expected. Please note the above.


Serial No.:

1/1
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
T
A
TA
CLP 4721
CLP 4726
TB 08 / Correcting Parts List - Dev. Release Motor etc. Pers-Hor/M
Date: 26-10-2011
T OPIC :
The part numbers of the developing release section are registered.
No. Old Part
No.
New Part
No. Description Q’ty Compatibility
Remarks
Old New Old New
1 ---------- 2KV31190 SPRING CLUTCH B - 1 - O *
2 ---------- 2KV31170 ARM CLUTCH C - 1 - O *
3 ---------- 2KV31130 GEAR Z36L - 1 - O *
4 ---------- 2HN31530 GEAR WORM - 1 - O *
5 ---------- 2KV00070 MOTOR- DC ASSY DLP - 1 - O *
* Set up to service parts this time
Classification: Entire Stock Rework
In-Field modification at next visit
In-Field modification by case
X No modification necessary
Field Measure: Service information only


Serial No.:
2
3
4
1
5

1/1
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 09 / Firmware Upgrade (ENGINE 006.002) 2KT-B387-B411/M
Date: 21-11-2011
T OPIC :
The firmware is upgraded as follows.
C ONTENT OF CHANGES :
 Fan control optimization.
The right side fan (for PWB cooling) is not stopped at Sleep. - Therefore, this is corrected.
 Corrective measures for the drum ghost image due to residing potential.
Change for the main charge adjustment: The primary transfer current is adjusted in conjunction with the MC setting of 1 to 5 in the service
menu.

 Corrective measures for the color shift due to cleaning failure at the calibration.
The color shift may occur if cleaning failure occurs with the color adjustment reference pattern on the primary transfer belt. - Therefore,
this is corrected.
Change: Cleaning bias to the cleaning fur brush at the calibration is changed from 2microA to 8microA.

 Toner consumption optimization.
The drum protection control is reviewed and its control table is changed to optimize the toner disposal at the normal operating
environment.
After the above change of the drum protection control table, conductive compound may adhere at the gap between the main charger roller
and the drum and white streaks in the drum circle interval if the machine is left 2 hours or more at high temperature and high humidity.
Therefore, preventive control for the white streaks is implemented.

FIRMWARE
Program No. Ver. Remarks
MAIN 2KV_3F00.002.005 002.005 New (CLP 3721, CLP 3726 / CLP 4721, CLP 4726)
ENGINE 2KT_1000.006.002 006.002 New (CLP 3721 / CLP 4721)
ENGINE 2KV_1000.006.002 006.002 New (CLP 3726 / CLP 4726)
Classification: Entire Stock Rework
In-Field modification at next visit
X In-Field modification by case
No modification necessary
Field Measure: Please upgrade the firmware when the phenomena arise.


Serial Nos.: CLP 3721 / CLP 4721
CLP 3726 / CLP 4726

Planned in October 2011 production

1/2
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 10 / Correcting Parts List - >DUCT… + HINGE LID< 2KT-B380/M
Date: 27-03-2012
Rev.1  HINGE LID L
T OPIC :
The following parts are set up for the service parts for an individual supply.
Upper tray
(PARTS LID TOP M ASSY SP)
DUCT LEFT INNER
(
No.1
)
DUCT LEFT INNER
HINGE LID R
(
No.2
)
Enlarged view
HINGE LID R

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No. Old Part
No.
New Part
No. Description Q’ty Compatibility Remarks
Old New Old New
1 - 2KV02250 DUCT LEFT INNER - 1 - O
2 - 2KV02542 HINGE LID R - 1 - O (right side)
3 - 2KV02532 HINGE LID L (left side)
Classification: Entire Stock Rework
In-Field modification at next visit
In-Field modification by case
X No modification necessary
Field Measure: Please order the parts according to the necessity.


Serial Nos.: This is for the service parts information only and is not applied to production.


1/3
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 11 / Firmware Upgrade (MAIN 003.007) 2KT-B453/M
Date: 04-01-2012
T OPIC :
The firmware is upgraded as follows.
C ONTENT OF CHANGES :
 UTAX/TA model name support.
The TA/UTAX model names are indicated on the report pages.
 Performance improvement.
Printing a certain PDF file is slow. - Therefore, this is corrected.

 Performance improvement.
It takes time to output a certain file created on PowerPoint (PCL-XL). - Therefore, this is corrected.

 Performance improvement.
Printing a certain data is slow. - Therefore, this is corrected.
 Corrective measures for the counter information abnormality sent via email.
Letter size counter information is 0 sent via email report. - Therefore, this is corrected.

 Corrective measures for the PDF direct print failure.
The KPDL error occurs when printing a certain PDF data. (Error Name: /syntaxerror). - Therefore, this is corrected.

 Corrective measures for the PDF direct print failure.
Wrong characters are printed in a large font when direct-printing a certain PDF file. - Therefore, this is corrected.
 Corrective measures for the PDF direct print failure.
The KPDL error occurs when direct-printing a certain PDF file. (Error Name: /undefinedresult, Offending Command: --show--)
Therefore, this is corrected.

 Corrective measures for the PDF direct print failure.
Polish may not be correctly printed when directly printing a certain PDF file. - Therefore, this is corrected.

 Corrective measures for the PDF direct print failure.
Print fails and "PDFConversionError" report is printed when direct-printing a certain PDF file. - Therefore, this is corrected.
 Corrective measures for the PDF direct print failure.
Characters are not partially printed when direct-printing a certain PDF file. - Therefore, this is corrected.

 Corrective measures for the PDF direct print failure.
Characters are garbled when direct-printing a certain PDF file. - Therefore, this is corrected.

 Corrective measures for the PDF direct print failure.
The KPDL error occurs when direct-printing a certain PDF file. (Error Name: /invalidrestore, Offending Command: --restore--)
Therefore, this is corrected.
 Corrective measures for the PDF direct print failure.
The B/W page may be printed in color when direct-printing a certain PDF data of color and B/W page mix. - Therefore, this is corrected.

 Corrective measures for the PDF direct print failure.
The KPDL error occurs when direct-printing a certain PDF file. (Error Name: /Typecheck). - Therefore, this is corrected.

 Corrective measures for the KPDL error.
The KPDL error occurs when direct-printing a certain PDF file. - Therefore, this is corrected.
 Corrective measures for the KPDL error.
The KPDL error occurs when direct-printing a certain KPDL data. - Therefore, this is corrected.

 Corrective measures for the KPDL font error.
The Helvetica-Bold font is not correctly printed when printing certain PS data. - Therefore, this is corrected.

 Corrective measures for the KPDL font error.
Characters with accents may not be correctly printed when printing a certain PS data. - Therefore, this is corrected.
 Corrective measures for the PCL-XL error.
The PCL-XL error occurs with a certain data. Therefore, this is corrected.

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
 Corrective measures for the PCL-XL error.
The PCL-XL error occurs when printing a certain PDF file. - Therefore, this is corrected.

 Corrective measures for the XPS error.
The XPS error occurs when printing a certain PDF file using the XPS driver. - Therefore, this is corrected.
 Corrective measures for the system error (CF248).
The CF248 error occurs with a certain data. - Therefore, this is corrected.

 Corrective measures for the system error (CF248).
The CF248 error may occur when printing a Mac Illustrator file. - Therefore, this is corrected.

 Corrective measures for the system error (CF248/CF46F).
The CF248/CF46F error occurs when printing a certain file from Mac. - Therefore, this is corrected.
 Corrective measures for the system error (CF258).
The CF258 error occurs with a certain data. - Therefore, this is corrected.

 Corrective measures for the system error (CF46F).
The CF46F error occurs after outputting the data in the midstream and stopping print when sending a certain aggregation data.
Therefore, this is corrected.

 Corrective measures for the lock-up with a certain data.
The PCL-XL error occurs or nothing is output while showing “Processing” with a certain data - Therefore, this is corrected.
 Corrective measures for the lock.
The “Processing” lock-up occurs with a certain data. - Therefore, this is corrected.

 Corrective measures for the image failure.
Colors may drop out when printing the Mac Illustrator file. - Therefore, this is corrected.

 Corrective measures for the image failure.
White streaks may appear when printing a certain data. - Therefore, this is corrected.
 Corrective measures for the image failure.
Undesired characters and lines may be printed with the PCL macro printing. - Therefore, this is corrected.

 Corrective measures for the image failure.
Image dropout of 6mm width may appear when setting [Gutter] in the KX driver. - Therefore, this is corrected.

 Corrective measures for the image failure.
Black streaks may appear when printing a Mac Illustrator file. - Therefore, this is corrected.
 Corrective measures for the image formation error.
Image formation may fail when printing using the GRRD command. - Therefore, this is corrected.

 Corrective measures for the PCL macro error not being called.
Ruled lines may not be printed with the PCL macro not being called. - Therefore, this is corrected.

 Corrective measures for the macro failure.
The 1st page text may not be printed when printing a macro data using a CF card (printing a macro only). - Therefore, this is corrected.
 Corrective measures for the failure that B/W data is printed in color.
A certain data intending B/W print is printed in color mode when using a macro. - Therefore, this is corrected.

 Corrective measures for the failure of outputting a blank pages with Prescribe.
A blank page may be output with a certain prescribe data. - Therefore, this is corrected

 Prevention of the Prescribe mode entry with a certain file.
If the character codes 0x21, 0x52 and 0x21 (!R!) exist in series in the PCL5 data, Prescribe mode is unintentionally entered and no data is
printed after that. - Therefore, this is corrected.
 Corrective measures for the barcode print failure.
Barcodes drop out partially when using the Barcode flash. - Therefore, this is corrected.

 Corrective measures for the form overlay failure.
Characters in the second page and after are rotated when inserting form overlay in Prolog/Epilog of the KX driver.
Therefore, this is corrected.

 Corrective measures for the Dutch status page message failure.
Translation of “Cyan” and “Yellow” in the toner gauge of the Dutch status page is incorrect. - Therefore, this is corrected.
 Corrective measures for the SMB protocol printing failure.
LF code may be ignored in the SMB protocol printing. - Therefore, this is corrected.

 DDNS cannot be registered.
DDNS cannot be registered in DHCP. - Therefore, this is corrected

 "admin00" password support.
 Preventive support for the Command Center setting not being changed.

3/3

FIRMWARE
Program No. Ver. Remarks
MAIN 2KV_3F00.003.007 003.007 New (CLP 3721, CLP 3726 / CLP 4721, CLP 4726)
ENGINE 2KT_1000.006.002 006.002 (CLP 3721 / CLP 4721)
ENGINE 2KV_1000.006.002 006.002 (CLP 3726 / CLP 4726)
Classification: Entire Stock Rework
In-Field modification at next visit
X In-Field modification by case
No modification necessary
Field Measure: Please upgrade the firmware when the phenomena arise.


Serial Nos.: CLP 3721 / CLP 4721
CLP 3726 / CLP 4726

Planned in December 2011 production

1/2
Technical Bulletin UTAX
UTAX CLP 3721 CLP 3726
TA
TA
CLP 4721
CLP 4726
TB 12 / Firmware Upgrade (color reg. drift / density) 2KT-C132/M
Date: 30-05-2012
T OPIC :
The engine firmware is upgraded for the corrective measures for the color registration drift and color image density down.
Upgrade the engine firmware as described in [Firmware upgrade procedures] when the color registration drift or color image
density down appears. Note the top margin and left margin may shift unless the firmware is upgraded as in the procedures.
C ONTENT OF CHANGES :
 Corrective measure for the color registration drift.
The reference color for the color registration adjustment is changed from K(Black) to M(Magenta).
The auto color registration adjustment control, LSU temperature compensation, LSU temperature control table and top margin adjustment,
etc. are changed after the above change.
 Corrective measures for the color image density down.
It is so changed that the developer units are not driven during warm-up after recovery from sleep mode and after cover closeto prevent the
developer powder deterioration.

FIRMWARE
Type Program No. Remarks
MAIN 2KV_3F00.003.007
ENGINE  CLP 3721 / CLP 4721 2KT_1000.007.004 NEW
ENGINE  CLP 3726 / CLP 4726 2KV_1000.007.004 NEW
F IRMWARE UPGRADE PROCEDURES :
Note: The engine firmware consists of (1) adjustment firmware and (2) upgrade firmware.
Prepare 2 pcs. of USB memory.
1. Print the service status page. <For check of the current firmware version>
2. Download the adjustment firmware.
Connect the USB memory with the adjustment firmware to the machine.
When completing download as shown in [Fig.1], turn the power off and disconnect
the USB memory.
Turn the power on and confirm [C9999] appears as in [Fig.2].
Turn the power off.
3. Download the upgrade firmware.
Connect the USB memory with the adjustment firmware to the machine.
When completing download as shown in [Fig.3], confirm the engine firmware version
is correct by pressing the upward or downward key.
Turn the power off and disconnect the USB memory.
4. Turn the power on and print the service status page to confirm the firmware
upgrade is correctly done.
5. Print the color registration chart and manually adjust the color registration (detail)
if necessary.
Reset Firmware Upgrade Firmware
CLP 3721 / CLP 4721 2KT_1000.CF5.001 2KT_1000.007.004
CLP 3726 / CLP 4726 2KV_1000.CF5.001 2KV_1000.007.004
Fig-2
Fig-1
Fig-3