image area expanding on the plate

lyzan

Well-known member
Hi,

I am having another problem with our Galileo VXT. Even the service engineers from our supplier are having a hard time fixing our/my problem.

The image area on the plates are expanding by max of 2mm causing misregistration in the press. The expansion is along the width of the plate (long side).

Any ideas what causing this problem?

TIA,
Lyzan
 
Does your FTP have temperature compensation? If not the problem could be the ambient temperature.

Best gordo
 
Hi,

I am having another problem with our Galileo VXT. Even the service engineers from our supplier are having a hard time fixing our/my problem.

The image area on the plates are expanding by max of 2mm causing misregistration in the press. The expansion is along the width of the plate (long side).

Any ideas what causing this problem?

TIA,
Lyzan

Hi, Expanding means stretching or misalignment along the slow scan?If you send a 4 colors job how many plates out of 4 are misregistered? I also would like to know the serial number of your machine.
 
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@gordo,

I have not heard any temperature compensation from the the service engineer for Agfa Galileo VXT.

@Armya

Image is stretching. For example if I have an imposition of 50 x 70cm (plate size is 1030 x 785mm), the imposition will become 50 x 70.2cm on two plates, then 50 x 70.1 on one plate, and 50 x 70.15 on another. Sometimes I will get identical stretch sized, but when run in the press the image especially on 2-3 colors text is misregistered. I'm not sure with the serial number, but on the label serial written is 51708.

Lyzan
 
@gordo,

I have not heard any temperature compensation from the the service engineer for Agfa Galileo VXT.

@Armya

Image is stretching. For example if I have an imposition of 50 x 70cm (plate size is 1030 x 785mm), the imposition will become 50 x 70.2cm on two plates, then 50 x 70.1 on one plate, and 50 x 70.15 on another. Sometimes I will get identical stretch sized, but when run in the press the image especially on 2-3 colors text is misregistered. I'm not sure with the serial number, but on the label serial written is 51708.

Lyzan

Start with small solutions and remedies.
This is what I suggest to do first:
Measure the distance between the plate stop blocks on the plate punch that will be used. If multiple plate punches are used, measure distance for each plate size accordingly.Use exact measurement between plate stops to maintain exact registration.Do you know how to do this? It is from middle to middle.
The Galileo 3-point registration system using the adjustable electromechanical pins and the
plate edge detector, maintaining a triangular configuration. External plate punching system must match Galileo registration system exactly.
Using the 20%-80% method can cause misregistration.If unable to make exact measure, the 20%-80% method will have to be used with its limitations.
1-Launch Galileo OCT.
Open the attached file.
2-Select Plate Information Icon or pull down window.
3-Under Pin Position, Distance between pins, enter the premeasured distance between the plate stops and apply. Do this for each plate size.


Hope this will help!
 

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Using the 20%-80% method can cause misregistration like plate (image) skew, but not image area expanding on the plate
 
Using the 20%-80% method can cause misregistration like plate (image) skew, but not image area expanding on the plate

A lack of temperature compensation when ambient conditions change can effect the size of the image on plate can't it?

gordo
 
A massive metallic drum of Galileo can't change its temperature so fast (dramatically) for 1 page-4 color CMYK to output sequentially and to get the misregistration.
Yeah, the first and the sixteenth plates could be different in size, if room is warming up in the morning for a few hours.
 
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@gordo,

I have not heard any temperature compensation from the the service engineer for Agfa Galileo VXT.

@Armya

Image is stretching. For example if I have an imposition of 50 x 70cm (plate size is 1030 x 785mm), the imposition will become 50 x 70.2cm on two plates, then 50 x 70.1 on one plate, and 50 x 70.15 on another. Sometimes I will get identical stretch sized, but when run in the press the image especially on 2-3 colors text is misregistered. I'm not sure with the serial number, but on the label serial written is 51708.

Lyzan


Hello Lyzan,

First; Isn't there a lenght calibration parameter in Agfa CtP ? I think your default expose is longer than original size in slowscan direction. Expose a geometry test and set the parameter correctly then you should measure 70 cm job as 70 cm on plate. not 70.2 cm

Second; When you measure a job shorter on plate, have you ever notice an exposure fault? I tought clutch which connects spindle and slowscan motor may got loose. In this case motor keeps turning but spinde might miss some steps. So the job would be shorter. But such a case you should see more or less visible thin lines on fastscan direction. If your jobs are just texts and shifting happens just on areas without images then you can't see any exposure problem.

I didn't work with Agfa CtP. These are just ideas without knowing machine. Hope they help
 
<<I tought clutch which connects spindle ... I didn't work with Agfa CtP. These are just ideas without knowing machine. Hope they help>>
AGFA Galileo CTP does not have any spindle to move the imager/carriage along a slow-scan.
Galileo has an Intelli-Track system (AGFA Avantra imagesetters have the same principle) - motorised carriage with digital and analog encoders to control the position and the speed.
 
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Thanks everyone for your reply.

@Farshad

That's the first thing I did two weeks ago until I noticed that the misregisration is caused by the expansion of image area. I am using 20-80% prior to this problem and read the Help menu that suggest the method that you mentioned. I have no luck changing Galileo's pin registration.

I received words from our supplier today telling me that they ask Agfa (Germany) about our problem. Looks like we need to change some parts in the carriage. Ahh...this Galileo VXT seems a complicated machine. We ask for help from our supplier about misregistration, their engineers came and left us with console error messages. Anyway, I hope they solve our problem as they are the only available support in this region.

Good thing this forum with you guys exists for much needed advice.

@Ozkan,

How I wish there's a parameter like that in Galileo Console. I have no access in the Diagnostic console. Only our supplier can access it which I wish I did have with manuals. It seems our supplier new service engineer is good in getting new console error message every time he access that diagnostic console :) (just kidding).

Thanks everyone.

Lyzan
 
@Vlad

Thanks for clarifying and explaining directly those things about Galileo VXT.

Lyzan
 
@Farshad

That's the first thing I did two weeks ago until I noticed that the misregisration is caused by the expansion of image area. I am using 20-80% prior to this problem and read the Help menu that suggest the method that you mentioned. I have no luck changing Galileo's pin registration.

That is good. Then I am sure now your feedback on expansion is correct if you did that procedure.

2nd step:

Check the video Cable coming from Carriage board to Carriage Assy. The video cable gets hot and possibly the Cable shield is burnt. This will cause the inner shield to have ground connection. If your Service Engineer has a new one. Replace and Test it.

Hope this will help!
 
@Farshad

I will take note of this. I will mention this to the service engineer. I have limited understanding of the cables connected to carriage assembly, I can only guess which is the video cable and possibly this is the rounded cable that looks like the color of a copper. I will surely mention this to the service engineer.

Thanks again.

Lyzan
 
@Farshad

I will take note of this. I will mention this to the service engineer. I have limited understanding of the cables connected to carriage assembly, I can only guess which is the video cable and possibly this is the rounded cable that looks like the color of a copper. I will surely mention this to the service engineer.

Thanks again.

Lyzan

That is the one! First check it out yourself . You wouldn't need to take the cable out, Just remove the top cover and look and Touch the cable. Make sure it is OK from start to the end.If it is OK., then put the cover back on with out mentioning this to the Service Engineer. If there is a problem with the cable mention this to Service Engineer. Be smart! Do not confuse your service engineer with smart questions like Temp/Humidity Compensation PCB or Drum Structure. This isn't time to give him lecture or criticize him.
You wouldn't need to put your Service Engineer in defense mode. Let him proceed with his troubleshooting procedure. He will be changing the Carriage Module PCB, edge detect sensor, edge detect PCB,system Module and you name it, until he finds the problem. This is very important.

3rd step: If the video cable is OK. then Check the Apis cable. You will need a new cable for this.

Hope this will help!
 
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@Farshad

Thanks. The video cable looks ok, at least the areas that I can touch and see. Around half of it is located into some kind of chain connected to the carriage assembly which I'm afraid to touch.

Also, I do not like to touch the Apis cable, I'm afraid because it feels like the dot matrix printer head cable which is sensitive to breaks.

Thank you very much to your effort to help me. You gave me ideas on the possible solutions and cause of my problem. I guess I have to wait now for our supplier's service engineer action. I will inform you all when this misregistration problem is fixed. For the meantime, we are outsourcing our platemaking.

Thanks again, everyone.

Lyzan
 
@Farshad

Thanks. The video cable looks ok, at least the areas that I can touch and see. Around half of it is located into some kind of chain connected to the carriage assembly which I'm afraid to touch.

Also, I do not like to touch the Apis cable, I'm afraid because it feels like the dot matrix printer head cable which is sensitive to breaks.

Thank you very much to your effort to help me. You gave me ideas on the possible solutions and cause of my problem. I guess I have to wait now for our supplier's service engineer action. I will inform you all when this misregistration problem is fixed. For the meantime, we are outsourcing our platemaking.

Thanks again, everyone.



Lyzan

Ok. You are a smart man, but one more thing. The Cable in the area of moving chain experiences this problem. If you feel the Cable not to be touched, then do not do it and let your Service Engineer to figure this out. Definitely, you wouldn't need me to tell you how you can make smart comments on Video Cable and Apis Cable to take his attention to these common causes of Image Expansion on the Plates first.

Wish you the best from Toronto, Canada.
 
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A massive metallic drum of Galileo can't change its temperature so fast (dramatically) for 1 page-4 color CMYK to output sequentially and to get the misregistration.
Yeah, the first and the sixteenth plates could be different in size, if room is warming up in Monday morning for a few hours.

I believe that the thermal expansion properties of aluminum are approximately 0.5mm expansion/contraction for a 5-degree C change in temperature (for a typical 1030mm 8-page plate). If the image is really changing by 2mm, you'd need a 20C change in temp between the first and last plate. Possible, yes... likely, no.

If it's actually a size issue, and not just a registration issue, I'd suspect something with the lead screw or encoder system - but you'd probably also have imaging artifacts if that were the case. Are there any banding issues? (would you even see them on the content you have though?)

Kevin.
 
@Farshad,

Thanks again.

Yes, I will make the service engineer to check that. Currently, our supplier is waiting for the arrival of the parts they think needed to be replaced.

@Kevin,

It is a size issue. Since this problem occurred, I am measuring the exposed area plate by plate, page size by page size. The image expansion is happening half portion of the plate. In Galileo, this is from the carriage home position to half of the plate up to maximum of 2mm. This means, in each plate of 4-color jobs, I am getting different sizes which is the reason for misregistration.

For example, if I have 8-up imposition with trim size of 210 x 297 mm, then measured it on the plate, I will get 210.5 x 297 and 210.75 x 297, while I get exact size at other half of the plate.

There are no other issues except for the expansion or enlargement of the image.

_____
Lyzan
 
@Farshad,

Thanks again.

Yes, I will make the service engineer to check that. Currently, our supplier is waiting for the arrival of the parts they think needed to be replaced.

@Kevin,

It is a size issue. Since this problem occurred, I am measuring the exposed area plate by plate, page size by page size. The image expansion is happening half portion of the plate. In Galileo, this is from the carriage home position to half of the plate up to maximum of 2mm. This means, in each plate of 4-color jobs, I am getting different sizes which is the reason for misregistration.

For example, if I have 8-up imposition with trim size of 210 x 297 mm, then measured it on the plate, I will get 210.5 x 297 and 210.75 x 297, while I get exact size at other half of the plate.

There are no other issues except for the expansion or enlargement of the image.

_____
Lyzan

My Pleasure! This is a complicated problem. I will do check
Apis Cable, Video cable and Hotlink . The last one has been added for your consideration as you provided more information for the Technical Issue.
If you have any questions please do not hesitate to contact me.
 
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