Assume you have already completed your undergrad and have been working for a number of years. Does one need to be part of a university or a learning institution to publish papers?
While it is not true that you should be in academia to publish papers, I'll give my two cents on what I learned so far:
If you work in industry and you write technical papers, your contributions are well-accepted, although they're typically more focused on certain practical aspects.
Authors writing by themselves are welcome, but they somehow are not very common because they lack the ability of writing an academic paper: they do not lack the message or the content of a paper, but just the structure, and that's something that you learn in an academic environment.
The reviewing process is not everywhere "double-blinded", so as a reviewer you do see the affiliation of who wrote the article, while they do not know you as a reviewer. I know that it's frowned upon, but I've read comments in the afterwards discussion (before the formal decisions) where reviewers pointed at the lack of a proper affiliation, or the "Who's this guy? where's s/he coming from?" sort of questions.
So all in all, there's no need to be an academic. But if you're not, stress enough your industry affiliation!
Technically, Maurice is right. You really don't have to be in academia to publish (even in academic journals). One famous example is Paul Erdos ( http://en.wikipedia.org/wiki/Paul_Erd%C5%91s#Career ), who I believe had no affiliation (at least in practice) for much of his life. However, most cultures have certain standard ways of doing things. Academia, and in particular the part of it that you want publish in, is no exception.
One thing you can do to help get your ideas accepted is to learn to write and talk in the language common to your research area. Specifically, find some papers in your area that you really like (even better if they are widely cited) and study how they are written. When you write your own papers, make a conscious effort to copy the writing style of the papers you like. One key part of this is to thoroughly know the relevant literature (previous work on the problem) and to mention it in your introduction and explain how your work relates to it. For each research area, there are numerous other hurdles you should jump. For example, if you're writing a math paper, do it in LaTeX. If you don't know LaTeX, learn it (ask Google, if you need help), since using it will make your paper more readily accepted. For a list of other criteria often used by mathematicians to quickly judge a paper, read http://www.scottaaronson.com/blog/?p=304 .
The Ronin Institute aims to facilitate precisely this type of independent scholarship. Its members include a number of very accomplished scholars who not do have university appointments yet publish regularly in top journals. Doubtless this is not the easiest route, but it clearly is not impossible either.
That said, the original question suggests that the researcher in question has a bachelor's degree but no PhD. In general, publishing from this position (with a bachelor's degree) would be more difficult than it would for a PhD who has left academia because the PhD would have had extensive immersion in academic culture and the experience in scholarly writing that comes with it.
Similar institutes are listed here.
Not necessarily. You can publish with your name only. In fact the value of the work is judged mainly by the readers who are the end users, and if you believe you can add something meaningful to the knowledge then go for it.
From my own experience, some universities take advantage of having their name thrown in while they provide little support to the work produced. Go for it and best of luck
Theoretically yes not but this is generally difficult, as requirements for the article will be higher and chances to prepare it really well are lower.
I would suggest to cooperate with some scientific institution that may also give good ideas how to improve the article. Maybe some extra experiments could be done using resources of that university. Or, if you represent a company, maybe a shared grant can be written getting more money for your project.
Also, unless you have experience in writing the scientific paper, it is very difficult to put everything into required structure, provide reasonable introduction with all necessary references and the like. A university professor can do this much easier as he does all the time.
In principle no, but...
In my field of study, you do have to declare some affiliation as an author. Publishers are claiming their submission system needs some official affiliation. A friend of mine was a senior co-author on one of my papers, and yet he holds no official degree (a renowned part-time investigator working as an architect). He opted to declare an institution within which he had many friends, and the editor was happy enough.
I believe however any official institution will do, even if not academic (e.g. Ministry for Environment, some private company).
Interesting question. You do not have to be affiliated to a university to publish papers, however, your paper will most likely be reviewed by (early) academics. They will judge your work according to their academic standards.
I am currently doing a PhD next to my work in public-private sector. I use a university affiliation when I publish. The interesting part is that often reviewers consider my (generalised) research questions and case studies to be unrealistic or non-relevant, while in fact they are directly obtained from my work and relevant.
On the other hand, if I stress the practical part (applied science), reviewers tend to judge my work as not novel (or should be well known) while my contributions are a novel application of scientific methods in practice.
In my modest experience it is difficult to bridge a gap between science and practice in publishing. Of course it also depends on the type of journal and its reviewers. It is not impossible. I am making progress.
In one of the answers is suggested to stress your industry affiliation. The author may be right. Reviewers may use different standards, or an editor may select reviewers with industry experience. I have not yet tried that approach.
Does one need to be part of a university or a learning institution to publish papers?
No, one doesn't. If your company is unrelated to your submission, it might be even wrong to put its name on it. However there is a practical aspect: providing the editor or the PC with the affiliation tells them a potential source of the conflicts of interest (COI). In other words, finding a reviewer without COI might get easier for them if the affiliation is listed. It is in your interest to support their work.
Some preprint services, such as MindRxiv, require you to have an affiliation with an institute to submit.