As mentioned a few posts above, I have the same issue (unable to print a second print job without disconnecting/reconnecting the printer).
I called Samsung today...I'm not sure I spoke to someone well versed on this particular issue, but their support rep told me my issue is that I don't have the CLP-315N model. He indicated that the "N" at the end of the model suggested network and that if I did not have this (ie. the CLP-315), I could only operate it by connecting it directly to my PC.
Any further info on the firmware update mentioned above?
Here is my assessment and solution as best as I can figure it. Pardon my in-depth description - can't help it, am engineer. From my experience, the problem with the Samsung CLP-315 printer dropping print jobs with OS X 10.6.3 or later can be solved by:
1) using the shortest possible high-quality USB printer cable, and
2) connecting directly to your computer, and not through a hub.
Those other solutions that depend on an external print server, as suggested in some of the posts above, accomplish the same thing - via improving the USB system electrically and using a local (non-apple) USB transmitter/controller.
I am a systems engineer with some years of experience sorting out systems problems, from high-level software through drivers as well as flaky high-speed signals, cables and grounding. Although most of my experience a with real-time mission-critical systems, insights from that area appear to be of some particular use here.
The CLP-315 issue is a confluence of small failures, each of which might be tolerated when connecting to a Mac with OS 10.6.3 and above, but when combined add up to failure:
1. The Samsung CLP-315 USB receiver has a weak electrical design - it is marginal at best, intolerant of suboptimal voltages and noise. Any small additional communication errors contribute to it giving up and throwing out your print job.
2. Samsung firmware and drivers are notoriously weak. By the way, Korea is almost entirely a Windows country due to historical quirks in their banking system (google that), which makes the use of Windows computers nearly mandatory there. Therefore Samsung has vanishingly few Macs and they do little OS X testing. The net result from the Samsung side is that when there are excess communication errors, your job is thrown out but the "job completed" message is still obtained. (By the way, the previous generation Samsung CLP-300 printer is a completely different beast, with entirely different hardware and firmware design).
3. Apple's USB electrical/controller system is marginal - compared to other computer makers, the hardware design is weak and under-tested for suboptimal or limit conditions - the Mac USB design tends to assume the ideal. I am not putting Apple down per se - I admit to being a huge Apple fan. But USB electrical difficulty with external hubs and/or long or poor cables is well known.
4. Apple's USB firmware/driver is underengineered, in that it has not been designed with a general-enough low-level exception handling philosophy. As a result it handles the links between software and electrical errors without robustness.
5. Apple's software design - i.e. for the USB channel and print handling - is all done at an extremely high level. When changes are made in the OS, sophisticated compilers handle all the mid- and low-level stuff. However, the compilers have not been designed particularly with reliability or real-time considerations in mind - instead they generally presume idealized system conditions.
So the whole USB printing situation for OS X + Samsung CLP-315 is a house of cards that easily collapses, and the result is that you lose your print jobs. Other printers have more margin for error built in and continue to work (I have a Brother printer simultaneously attached to my Macbook Pro, under horrible conditions - via a long poor-quality cable through a 10-port underpowered hub - and it works flawlessly, while my Samsung CLP-315 was consistently dropping jobs).
When Apple went to 10.6.3, a tiny incremental amount of additional high-level print/USB handling complexity was added, and this in turn caused a small amount of additional delay and miscommunication. That, with a weak Samsung USB setup, was just enough to break the camel's back.
Because the problem is essentially one of design philosophy, under-design and marginality, we have no solution from Samsung, and no solution from Apple.
From Samsung's point of view, so far as OS X goes, the CLP-315 works fine under so long as you're running Windows (slight sarcasm from me, though it's true). From Apple's point of view, when ideal Apple USB conditions and ideal printer conditions are assumed, the high-level code is flawless, and simple and full-spec electrical conditions are assumed.
High-level code in non-real-time software, e.g. 10.6.3 - 10.6.7 and 10.6.xx and 10.7.x, is profoundly unaware of hardware delays - everything is assumed to run on an ideal machine. For example, as a systems engineer, I sometimes get a good belly laugh from launching a whole bunch of processes on OS X and seeing them get all balled up because of race conditions. And remember, I'm an Apple fan and I love my Mac.
As other poster documented, there is lots of finger-pointing between Samsung and Apple, and because of their outlooks, noting is going to change there. Samsung thinks in terms of Windows, and it's amazing that we have any Apple stuff from them at all. They assume a Windows USB electrical setup, and since Windows users aren't complaining, there is no problem. Apple, for their part, lives in the cloudlike and bright-white world of the ideal, and real-time considerations and dirty stuff like that is something for some other kind of nerd. Other printers work, so it must be a Samsung problem. In the end, it's neither and both are the same time, and zero progress will be made.
So I would buckle up, and either a) connect your finicky Samsung 315 directly to your Mac with a very short high-quality cable, no hub, or b) get an external print server as suggested by one of the posters (one of them gave an e.g. link at http://www.dustin.se/productdetails.aspx?prodid=5010469570&s=b&intcmp=bus_sel ). With an external print server, the weakness of the Samsung USB setup is compensated for by a stronger USB system in the server.
Forgive me going on about it, but this is an interesting topic, and I put up with the flaky Samsung 315 for a long time too. Best wishes to everyone - let us know how it work out for you.
I found your post very useful and of great detail, and being an undergraduate electrical engineer myself, i would say that it makes a lot of sense!
But i still think that Apple & Samsung should be responsible of their product and most of all, of their customers and if they can not provide us with a solution at least they could come up with a simple explanation, as you could do.
Anyway, in addition i would like to ask everyone's opinion and experience about the USB cable's length they use to connect the printer to the MAC. I am using a 3meter long cable and i facing the problem so i would go to the option of the 1.5m but if someone had tried that too without good results maybe i should even try the 1m long one.
Thank you all in advance for the feedback.
<Edited by Host>
I have the same problem with my printer.
Apple support is a joke. I have left a number of inquiries on the support, but only after being guided in circles obviously to avoid the critics.
According to Samsung support, the printer is working with the OS system, and according to Apple support they have no solution to the problem.
Dear Apple folks- get on with the work an come with a solution.
Motley1, that was a nice post.
I started to look at the Printer Manual and Box... and it never shows the USB-Certifed Logo.
This means that the USB Device Controller it has is not certified.
I still think this is a software issue. USB uses a balanced twisted pair (half duplex). As long as the length of the cable is less than 5 meters (according to USB Specs), I think it should work fine.
If the problem is electrical, then it should not start working after a power reset or a cable plug/unplug.
This unloads the kernel-side memory reserved for the printer and reloads it again.. and it works the first time you use that instance of the loaded driver. After that, some routine gets hang up, and it stops responding.
I think it is clear by now that neither Apple or Samsung plans to fix this issue. They are too busy competing with each other on Tablets.
I finally got through to someone at Samsung support who was able to help. They provided me with a firmware updater for the CLP-315 which resolved the problem. The updater requires Windows. Contact Samsung if you have this problem and request the firmware update. I don't know why they don't just make it available on their support website, but at least an update exists.. Hope this helps!