Designjet 500 has started printing bands on prints NOTHING seems to fix this problem.

[Kiran Otter]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

The only way to get at the roller encoder disc and sensor is to take the top half of the printer off. There are 4 spring-loaded screws that attach the two arches on either end to the base of the printer. You have to disconnect all the wires from the emod, some of the back cover parts by the spindle ends, there's a ground strap near the left spittoon with a T-10 screw that has to be removed, and remove the tube assembly from the ISS, if I remember correctly. The entire top half of the printer can be lifted off, exposing the main roller and the small cover on the left end that covers the encoder disc and sensor. I would replace both since you're taking it that far apart.

Read the part in the manual regarding removing the Drive Roller. It'll give you some idea of what has to be done. I don't recall having to remove the back platen, for example.

You can cheat a bit and just undo the 4 screws at the arches and jack the left end of the top half up so you can get that little cover off that covers the encoder. I just found it easier to remove the entire top half. The manual lies about removing that encoder cover without taking the top half off, I never found a way to get it out.

Kiran

[blackcat4866]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

If it's as consistent as you suggest, I'd suspect the encoder wheel itself. You'll probably discover either ink obscuring the lines on the disk, or scratches where the wheel has contacted the side of the read sensor. As Kiran says, it's a major operation to get to it, so have the encoder disk and sensor on-hand before you start disassembly. =^..^=

[Lance15]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

Came across this problem years ago. After explaining the amount of work required and price per hour, the customer decided not to continue.

[D Hook]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

Have to agree with the other posters. It's not a quick or easy job. But if you're mechanically inclined and have some patience it's very doable. Too bad your not closer; I'd come over and do it for a flat fee.

I would suggest you check with LPS Computers and see if they have an encoder wheel before you start. They should be pretty cheap.

I'd still suggest printing out a demo print from the front panel though, just to rule out the encoder wheel. If it shows the same skip in the same intervals, then you have a good reason to disassemble and replace/clean the encoder wheel and the sensor.

[Kiran Otter]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

LPS has the disc and sensor for $70.

Designjet 500 | Drive Roller Encoder Sensor | C7769-60384

Kiran

[RHOPKINS]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

You got that right forget trying to get to that cover. Well I am going to print a internal print first. Then if that fails I sure hope that top piece comes off easy that than what I tried. Know about the ground strap. If I can get to it I will replace both to much trouble to get to one and not do that. Richard

The only way to get at the roller encoder disc and sensor is to take the top half of the printer off. There are 4 spring-loaded screws that attach the two arches on either end to the base of the printer. You have to disconnect all the wires from the emod, some of the back cover parts by the spindle ends, there's a ground strap near the left spittoon with a T-10 screw that has to be removed, and remove the tube assembly from the ISS, if I remember correctly. The entire top half of the printer can be lifted off, exposing the main roller and the small cover on the left end that covers the encoder disc and sensor. I would replace both since you're taking it that far apart.

Read the part in the manual regarding removing the Drive Roller. It'll give you some idea of what has to be done. I don't recall having to remove the back platen, for example.

You can cheat a bit and just undo the 4 screws at the arches and jack the left end of the top half up so you can get that little cover off that covers the encoder. I just found it easier to remove the entire top half. The manual lies about removing that encoder cover without taking the top half off, I never found a way to get it out.

Kiran

[blackcat4866]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

... If I can get to it I will replace both to much trouble to get to one and not do that. Richard

I agree 100% =^..^=

[RHOPKINS]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

Please post up an image of a demo print you've recently printed from the printer's front panel. This will confirm if the printer is at fault or the program you're using. If the demo prints out fine, then the printer is working as expected and you can focus efforts elsewhere before tearing the machine apart or getting the parts cannon loaded.

Well the demo print had the same problem D Hook. I have removed the main carriage and got to the decoder. It looks clean as a whistle. The gears are pretty dry.

Here are some shots of the drive encoder wheel on the platen rollers, and the encoder on the back of the motor. Do you suggest I replace the motor and the platen encoder? Richardencoder wheel.jpg

[RHOPKINS]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

Well the demo print had the same problem D Hook. I have removed the main carriage and got to the decoder. It looks clean as a whistle. The gears are pretty dry.

Here are some shots of the drive encoder wheel on the platen rollers, and the encoder on the back of the motor. Do you suggest I replace the motor and the platen encoder? Richard[ATTACH=CONFIG]53620[/ATTACH]

Motor encoder assy.encoder on back of feed motor.jpg

[RHOPKINS]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

Well I have got the machine taken apart. It was not to bad to disassemble the main housing assy. Looking at the encoder wheels they all look clean. But I can see how the slightest bit of dust would really mess things up. Is it advisable to replace both the motor and encoder? Where can I get some of this grease that is on the gears they are really dry?

thanks
Richard

[RHOPKINS]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

encoder on motor rear.jpgEncoder at rear of motor.

[RHOPKINS]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

encoder wheel.jpgEncoder located on platen.

[D Hook]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

[ATTACH=CONFIG]53622[/ATTACH]Encoder at rear of motor.

I see something orange on the outer edge of the wheel. Can you tell what that is? Or maybe it's something that's just behind the wheel and not actually on the wheel.

Might examine the inside of the cap too. Be sure it's clean inside and no grease present.

GENTLY wipe the wheel with a damp coffee filter. Only water. Coffee filters are lint free. Clean both sides. Don't rub too hard so you don't rub the marks off. (If there are any.)

Not sure about replacing both wheel and sensor or wheel and motor. Maybe Kiran or someone has a suggestion on how to proceed with replacement parts.

On the T1200 I had that showed the same problem I only had to replace the encoder wheel. But it was contaminated with grease from the inside of the plastic cover. Came that way from the factory.

[Kiran Otter]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

I've never once had to replace the paper axis motor. I would just replace the roller encoder sensor and disc.

Kiran

[D Hook]

Re: Designjet 500 has started printing bands on prints NOTHING seems to fix this prob

I seem to recall having some parts from a 500 printer laying around. Let me check for the encoder/motor/sensor assembly tomorrow.