What is SKY SHOT used for?

[Copier Mechanic]

Re: What is SKY SHOT used for?

A sky shot was used on old analogue copiers to check for print defects, white lines / deletions or fusing issues. Lift up the ADF of plattern cover & do a copy of the sky. The Copy would be totally black.

This 'test' method is not needed now as all copiers can generate a test print using service mode etc.

Gotcha, that makes sense. Thanks!!

[copier tech]

Re: What is SKY SHOT used for?

hey guys,

Since I am fairly new to the copier industry, I wanted to ask here about the SKY SHOT thing that I have heard. What is exactly is it used for???

A sky shot was used on old analogue copiers to check for print defects, white lines / deletions or fusing issues. Lift up the ADF of plattern cover & do a copy of the sky. The Copy would be totally black.

This 'test' method is not needed now as all copiers can generate a test print using service mode etc.

[slimslob]

Re: What is SKY SHOT used for?

This might be a useful method for diagnosing production print devices, but many 30cpm and less devices cannot re-supply toner fast enough to maintain developer density on images >50% fill, maybe 15pgs? I remember demonstrating this to my Konica Minolta rep on a bizhub C284e. He kept trying to tell me that it was impossible ... funny how I could repeatedly demonstrate it though? The customer was printing full 11x17 pages of Pantone 3155 (C: 100, M: 13, Y:0, K: 53). NOTE: C: 100%!! I wonder why the cyan developer kept detoning, LOL???

On most devices, a better way to determine developer viability is by checking the momentary toner density value, and to check heavy fill images for unfused or gritty areas (transferring developer starter). Also check for an extraordinarily heavy waste bottle (means that most of your developer is now in the waste bottle). =^..^=

That is why I usually used Ricoh's checkered flag test pattern.

[blackcat4866]

Re: What is SKY SHOT used for?

More a matter of if you run 500 sky shots and the image quality is not consistent for the entire run, you have a toner supply problem. If the density does not vary but is a lighter gray scale shade the problem could be dirty optics or dirty laser shield glass.

This might be a useful method for diagnosing production print devices, but many 30cpm and less devices cannot re-supply toner fast enough to maintain developer density on images >50% fill, maybe 15pgs? I remember demonstrating this to my Konica Minolta rep on a bizhub C284e. He kept trying to tell me that it was impossible ... funny how I could repeatedly demonstrate it though? The customer was printing full 11x17 pages of Pantone 3155 (C: 100, M: 13, Y:0, K: 53). NOTE: C: 100%!! I wonder why the cyan developer kept detoning, LOL???

On most devices, a better way to determine developer viability is by checking the momentary toner density value, and to check heavy fill images for unfused or gritty areas (transferring developer starter). Also check for an extraordinarily heavy waste bottle (means that most of your developer is now in the waste bottle). =^..^=

[slimslob]

Re: What is SKY SHOT used for?

mmmh...interesting, so if you were to get a full solid dark black image on entire page then obviously the Developer is doing its job correctly but if you were to get a really light black image almost like greyish, then you would have a bad developer right? or perhaps maybe even a worn out surface drum too right?

More a matter of if you run 500 sky shots and the image quality is not consistent for the entire run, you have a toner supply problem. If the density does not vary but is a lighter gray scale shade the problem could be dirty optics or dirty laser shield glass.

[Copier Mechanic]

Re: What is SKY SHOT used for?

I use primarily to test toner supply issues.

Another helpful hint: Place a blank sheet an inch or two on the left side of the glass. That way you will have a nice white lead edge to avoid fuser jams, but still get the affects of a skyshot.

mmmh...interesting, so if you were to get a full solid dark black image on entire page then obviously the Developer is doing its job correctly but if you were to get a really light black image almost like greyish, then you would have a bad developer right? or perhaps maybe even a worn out surface drum too right?

[Tonerkiller]

Re: What is SKY SHOT used for?

I will still use them to see if the fusing rollers are worn or not.

[JVergin]

Re: What is SKY SHOT used for?

Some Kyocera models are notorious for developer leak issues, which can be very easily confirmed using a skyshot and selecting a single color to print.

[slimslob]

Re: What is SKY SHOT used for?

Lol.

Note: Do not use sky shots as an image quality test for black images. Depending on the angle of the room lights, you can get unaccountable gray shadows. I've wasted an embarrassing amount of time trying to fix those anomalies, only to later discover it was caused by room lights.

If your objective is to consume toner out of the developer mix (and that is a legitimate purpose), create an electronic image 8 1/2 x 11, with 25mm wide lead and trail voids, so you won't have to fish those heavy fill images out of the fuser, when they try to wrap onto the fuser roller. I might have an example:

Another reason you might want a skyshot is setting nipp width. That same electronic image works better than the sky shot. =^..^=

I don't know about Kyo but with Ricoh I always used the Checkered Flag test pattern. It is only 50% coverage so takes a bit longer to reduce over toning but it also reduces the on time of the laser diodes.

[JR Skewing]

Re: What is SKY SHOT used for?

In olden times (when exposure lamps were MUCH stronger than today), a sky shot was useful to cause a pesky customer to depart the area.
...Lorenzo

[JR2ALTA]

Re: What is SKY SHOT used for?

As previously mentioned, it can be used to deplete the developer of toner. Useful if you want to trigger an add toner cycle and can't be bothered running it in service mode.

If I replace a toner motor or hopper, I prefer the sky shots vs service mode because: 1) It mimics real-world usage, therefore lessening the chance of a callback. 2) I can monitor the quality for consistency. That said, I usually sneak out all the printouts to not raise any eyebrows with the customer

[Black Cloud]

Re: What is SKY SHOT used for?

A sky shot can also be used to do a fusing unit test. If the coating is worn on the hot roller, you will see the tracks/pattern in the solids of the sky shot. (Which will also be visible in offset for a few pages thereafter). This is especially useful on models that have fusing unit components that are not easily viewed.

It can also be used to demonstrate the void edges to a customer who likes to print to the edge of the paper and is complaining that some of their border lines are not being printed.

As previously mentioned, it can be used to deplete the developer of toner. Useful if you want to trigger an add toner cycle and can't be bothered running it in service mode.

The sky shot can even expose extreme humidity in paper. (The dampest part will have less toner). Although the rubbing the back of your fingers across the paper and feeling cool rather than neutral temperature is also a good way to spot check humid paper.

[KenB]

Re: What is SKY SHOT used for?

Back in the olden days of analog copiers, we had to use sky shots in order to check the nip width.

You would turn the machine off when the copy was about halfway through the fuser.

After doing that a few times, I determined that making a copy (with the cover closed) of a letter sized sheet of black construction paper was a much more civilized alternative.

[JR2ALTA]

Re: What is SKY SHOT used for?

I use primarily to test toner supply issues.

Another helpful hint: Place a blank sheet an inch or two on the left side of the glass. That way you will have a nice white lead edge to avoid fuser jams, but still get the affects of a skyshot.

[blackcat4866]

Re: What is SKY SHOT used for?

thanks for the info sir. never considered that might be a factor, lights in the room...

... two drums, and a developer change later ... yes, I learned the hard way. =^..^=