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 | HP designjet 450 - not taking paper by suzuki (3/27/06 6:30 AM) reply | + / - | I have a designjet 450c that starts up normally and displays "load media". When I feed in either a roll or sheet it takes it in, the cartridge holder comes over , halts momentarily near the right hand edge of the paper and then goes straight back to the home position on the left hand side. The machine spits out the paper and the light flashes "load media".
If I load the paper crooked I am prompted to "align media" but with the same result. I notice that there is no red light underneath the cartridge holder to check the paper edge, shouldn't this come on?
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 | Re: HP designjet 450 - not taking paper by dmzcompute  (3/27/06 2:25 PM) reply | + / - | Yes it should. Here is my suggestion. Remove the top cover and stick some paper into the switch on the left side of the menu to simulate the cover closed. Now power on the plotter and watch what happens. The carriage assembly should move all the way to the right and then back to the left. If will then move to the right again and then back to the left and start to find the mark encoder which is a white piece on the left end of the paper platen. You should see the red light come on underneath on the right side of the carraige assembly as it tries to read the mark encoder. Does the red light come on? If not I really do not see how the printer can come to load media unless you get all three lights on the right and then yu hit cancel and then it say load media. That sensor does have a habit of picking up a lot of black ink. If the plotter is old and has been used a lot, it is possible the sensor is clogged with ink. The best way to clean it is to remove the left side cover and remove the service station. You will then have access to that sensor without having to remove the carriage assembly from the plotter. The other thing you will want to do is clean the encoder strip with a damp lint free cloth.
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| Re: Re: HP designjet 450 - not taking paper by suzuki (3/27/06 11:56 PM) reply | + / - | Thanks for your reply. Yes, I do have to hit "cancel" before " load media" comes on.
I tried sliding a sheet of paper soaked in alcohol under the sensor but it came out unmarked and I cannot see even a glimmer of a red light. Is the sensor gone or could the fault be more serious?
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| Re: HP designjet 450 - not taking paper by dmzcompute (3/28/06 5:26 AM) reply | + / - | It can be the sensor, the carriage assembly control board or even the trailing cable. First thing I would do is check the small ribbon cable which runs from the top of the carriage assembly to the sensor. It is on the right side of the carriage assembly and plugs in at the top. If ok I would remove the carriage assembly and flip it over and check the hole with the sensor lens to make sure it is not clogged or even missing. I would then put everything back together and see what happens. If it still does not work, I would replace both the trailing cable and the carriage assembly.
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| Re: Re: HP designjet 450 - not taking paper by Anonymous (3/31/06 6:39 AM) reply | + / - | Did what you suggested and cleaned all the gunk from under the sensor.
Now I can see a red spotlight from the sensor but after loading paper it still behaves the same and ejects the page. I guess I'll order a carriage ass. and hope for the best.
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| Re: HP designjet 450 - not taking paper by dmzcompute (3/31/06 5:05 PM) reply | + / - | What is the light pattern error you get before you hit the cancel button.
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| Re: HP designjet 450 - not taking paper by Stephen (3/31/06 5:44 PM) reply | + / - | The red light has to be reflected back to a sensor, if the sensor slill has some ink on it, then it might not be able to "see" the light.
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| Re: HP designjet 450 - not taking paper by dmzcompute (3/31/06 6:51 PM) reply | + / - | Stephen I am sure the sensor is clean after he cleaned it. My best guess is he has a mark encoder error where the carriage cannot find the white mark encoder on the left of the platen. It could be the carriage assembly or even the trailing cable or a combination of both. It could also be that the mark encoder white piece has fallen off and is laying at the bottom. However, that said, the most common issue is the encoder strip which runs thru the carriage assembly and has fine black lines which tell the carriage assembly its position. If that strip has become damaged where some of the lines are messed up or missing or even if it is very dirty, then the carriage assembly does not move to the correct position to read the mark encoder. Cleaning the encoder strip or at least inspecting it on the left side is a must and replacing if damaged. I have seen more issues with the trailing cable, then with the actual carriage assembly. To be honest when we run into this situation and it is not the encoder, we always replace both the trailing cable and the carriage assembly, even though it is very expensive.
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 | Re: HP designjet 450 - not taking paper by adrian pillay (10/5/06 2:06 AM) reply | + / - | Hello All
I have a hp designjet 450c, when i load an A4 size cut sheet, it takes the paper in but does not go under the star rollers, the carriage comes to the right and squashes the paper. The star roller assembly does'nt move at all. Does anyone know what can be causing this problem?
Much appreciated
Adrian
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| Re: HP designjet 450 - not taking paper by Jerry Fischer (8/27/08 3:13 PM) reply | + / - | My hp 450 C designjet recently refused to take paper. I bought it used and when it arrived, there was black ink lots of places and I have had it about half way torn apart cleaning up the ink. That was about 6 months ago and it has been working well since I replaced the shreaded carriage drive belt.
It now fails to find the index mark at the left end of the paper drive roller or the edge of the paper when I insert it even though the red light comes on.
If fails the self test and leaves the amber carteridge and data lights turned on.
I have had the cutter pickup and sensor cover off and unplugged the sensor. There was ink on the ribbon cable to the sensor but none on the connector, the LED or the sensor lens. I have examined the trailing cable without finding any discoloration or cracks.
My conclusion is that it seems likely that the sensor or the trailing cable has failed. It seems a lot of overkill to replace the carriage if that little sensor is bad and almost as much overkill to replace the trailing cable (if the sensor is bad). On the other hand, the trailing cable is the only thing that is flexing during operation.
Suggestions are welcome.
Jerry
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| Re: HP designjet 450 - not taking paper by dmzcompute (8/27/08 4:53 PM) reply | + / - | Keep in mind it has to find the mark encoder. Do you see the white piece on the left side of the platen and does the carriage assembly sensor go over that shinning a red light down and does the mark encoder get the light shinned on it. You could have a dirty or missing mark encoder. You could have a bad or very dirty encoder strip (clear plastic strip thru back of carriage complete width of plotter). Clean the encoder and check the fine lines to make sure none are deformed or missing. If the carriage can not find the right spot to look for the mark encoder then it will not find it.
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| Re: Re: HP designjet 450 - not taking paper by Anonymous (8/27/08 7:38 PM) reply | + / - | The roll index is on the roller and the red light shines on it when the roll rotates. The index passes the red light, and is not seen. The carriage moves slightly, then the roll rotates again and the index passes the red light without being sensed.
I remember that when the index mark passed below the red light before, it would stop and rotate past the light slower for a more precise sighting. That does not happen now.
Jerry Fischer
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| Re: HP designjet 450 - not taking paper by dmzcompute (8/27/08 8:20 PM) reply | + / - | Also clean the white mark encoder itself.
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| Re: HP designjet 450 - not taking paper by mpalatas (9/1/08 12:58 PM) reply | + / - | I have a similar problem. Starts up, data and cartridge light on blinking, press CANCEL, and then the Load Media green light energizes solid. Feed the leading edge in, press the load media blue button, everything seems to work fine, it takes the paper, feeds it, then asks you to align it, then, after the alignment, it cuts the 2" of paper, the carriage goes over to the right side, backs off to the left about 4 inches. The red sensor led energizes bright for a second or two, but then it dims. The carriage moves to the right - just past the paper edge, but immediately goes left again to return. The paper then unfeeds and you get the blinking media light again.
You can repeat the process over and over with the same results.
I have passed a q-tip over the underside of what I think is the media sensor - the small protrusion on the right, back, lower side of the carriage to clean it but it has no affect. I am not positive that is the media sensor though, because it is never called out that I can find in the Service Manual. Doing the Service Mode 1 test of the Sensors leaves only the pinchwheel and cover sensor lights lit - the media sensor light is dark. HELP!!
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| Re: HP designjet 450 - not taking paper by dmzcompute (9/1/08 2:05 PM) reply | + / - | Try changing to sheet media and load a regular 8.5x11 sheet and tell us what happens. Also watch the sheet as it is loading to see if it skews to one side you stays striaght. Also disconnect the printer from the computer as the data light flasing may be data trying to print. There is no errro message for both those lights flashing at the same time.
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| Re: Re: HP designjet 450 - not taking paper by Anonymous (9/2/08 8:01 AM) reply | + / - | I disconnected the printer cable, cleaned and inspected the plastic strip with position indicator lines thereon, cleaned the white slotted marker at the left end of the printer roller and turned on the printer. The roll index (slotted white marker) passed the red light with the roller going forward and backward at least 4 times with no indication that the marker was sensed. (Previously the roll would stop turning when the marker was sensed.) When the startup procedure was finished, the cartridge and data lights were on.
I pressed the cancel button, both lights went out. I tried to load a sheet of typing paper. It entered the printer properly, straight. The carriage passed over it from left to right as it should. When it tried to sense the edge of the paper moving from right to left, it paused about 4 inches onto the paper, then returned to the left parking position and the media light came on and the paper was ejected.
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| Re: Re: HP designjet 450 - not taking paper by mpalatas (9/5/08 6:13 PM) reply | + / - | We did. Same result. We finally figured out, though, the difference between the media sensor (under the blue paper feed button) and the line sensor (on the right side of the carriage assembly. Finding that out, we entered Service Mode 1 again and performed the sensor test - got the media sensor light to come on and off when we put a piece of paper under the paper feed button and then removed it. So that tells us the media sensor is OK.
We then performed the Carriage Test - and the Analog Multiplexer light came on flashing - indicating a bad analog multiplexer. The Service Manual says step one is to replace the trailing cable, but this is practically brand new machine and the cable looks just fine. Next is to replace the carriage assembly.
Since you have been so kind as to respond with your technical expertise, do you have either the trailing cable or carriage assembly that we could buy from you? I suppose that the trailing cable is pretty cheap versus the carriage assembly. What do you recommend first. You can email me at mike.palatas@nasmedical.com. Thanks.
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| Re: HP designjet 450 - not taking paper by Jerry Fischer (9/19/08 2:29 PM) reply | +1 + / - | My HP designjet 450 will not take paper. I have checked the sensors as suggested earlier in this thread with no sign of sensor errors. When I do a carriage test in service mode 1, I get an Analog Multiplexer error.
I have examined the outside of the electronics module and find no obvious problems (ink leaking into it for example) I could pull the cover and blow out any dust accumulation (helps my PC sometimes) but have not yet.
What are my options?
Jerry Fischer
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| Re: HP designjet 450 - not taking paper by dmzcompute (9/19/08 4:02 PM) reply | + / - | Both users above you need to clean the encoder strip that runs thru the back of the carriage assembly. Look at is closely especially on the left side to make sure none of the fine lines are damaged or malformed. Try again and let us know the resutls. Most times if this does not solve the issue, replacing the carriage assembly and trailing cable takes care of it.
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| Re: HP designjet 450 - not taking paper by Jerry Fischer (9/22/08 7:41 AM) reply | + / - | Jerry Fischer cont.
This was a used printer that we bought over the internet. When it arrived there was black ink everywhere. I dis-assembled it and cleaned ink many places, cleaned the spittoon(sp?), service station, and roller. I did NOT clean the PC board on the carriage. There is a possibility that there is ink on that assembly and connectors. However, the printer worked normally for a while. I have made many prints using both cut and roll media. Then it failed.
I have wiped the encoder strip with a damp cloth, inspected it with a 10 power loupe and can find no damage to the encoder lines. In normal mode, when it powers on, the carriage moves normally, finally positioning itself over the white slotted roll index mark at the left edge of the roll. The roll rotates passing the white marker under the red LED (which I have inspected and find no ink in either the led or the sensor pocket). There is no indication that the white marker is sensed.
When the printer works normally, when the white marker passes under the red sensor light, it stops, reverses, and moves slower for a more accurate pickup. The marker moves under the red light with no indication it is being sensed. Eventually the startup self test finishes leaving the cartridge, data, and ready lights on. When an A size sheet is introduced, it enters the printer normally, the bail lifts and accepts the paper, the carriage moves to the right, the red light in the carriage paper sensor comes on, passes over the edge of the paper moving to the right and left, then the carriage moves to park position and the paper is ejected.
When I perform a carriage continuity test in service mode 1, it returns an analog multiplexer error (fast print light flashing.)
Earlier I found ink on the cable from the line sensor to the carriage and cleaned it while checking for ink in the pockets where the led and sensors are.
I seem to be left with the possibility of ink shorting connectors in the carriage assembly, broken circuits on the trailing cable assembly, a bad sensor (the red light comes on = LED OK) in the line sensor assembly, or failure in the electronics module (Which looks REALLY expensive, probably more than we paid for the printer).
How do you suggest I proceed from here?
Jerry Fischer
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 | Re: Re: HP designjet 450 - not taking paper by Anonymous (9/26/08 7:38 AM) reply | + / - | "When the printer works normally, when the white marker passes under the red sensor light, it stops, reverses, and moves slower for a more accurate pickup. The marker moves under the red light with no indication it is being sensed. Eventually the startup self test finishes leaving the cartridge, data, and ready lights on. When an A size sheet is introduced, it enters the printer normally, the bail lifts and accepts the paper, the carriage moves to the right, the red light in the carriage paper sensor comes on, passes over the edge of the paper moving to the right and left, then the carriage moves to park position and the paper is ejected."
This unit needs to have the Accuracy Calibaration done to recalibrate the line sensor sensitity. It seems to drift over long times. Manual says to use Matte Film but most do not have any. Just use whatever paper you normally run through the plotter and all will be fine. Have done this on many of this series and always fixes this issue. If you are unable to complete the calibration ( uses service mode2 )because the media light comes on when you feed the sheet in, then I expect the media sensor, under the load switch, is defective.
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| Re: HP designjet 450 - not taking paper by Jerry Fischer (10/27/08 12:53 PM) reply | + / - | Given that I have checked everything I can think of in reference to the service test that indicates a multiplexer analog test failure, and that the suggested proceedure is to replace the trailing cable, the carriage assembly, or the electronic module in that order; what are the prices and availability of those items?
You can contact me at 580 515 5726 or my email jerry@tntmold.com
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| Re: HP designjet 450 - not taking paper by leppy (10/29/08 10:09 AM) reply | + / - | my problem is that once you turn on the machine it goes through all its checks, after a few minutes it stops (often returning the end of the roll of paper out of the printer) the cartridge and data lights turn on...
when you press cancel the media light displays blinking wile the normal, film, and roll lights stay constant....
when cancel is pushed again the media light turns off and the ready light blinks...
in service mode #1 performed all the tests listed and after i realized where the media sensor was, all tests passed...
i re-ran the modular test and the only thing that seemed to be missing was the coated light which means the front panel sensor... but when i pressed the cancel and media source buttons to cancel the test... it immediately came on...
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