The function of a research journal is to set down on paper your thoughts about the primary and secondary source material you are reading. It is a record of your questions about the material and your tentative answers to those questions. It documents the connections you make between the materials you read, and provides a place to record the questions this material raises . Publishing in academia is the need to get your name out in the field, and build your academic reputation.
The objective of the journal is to record your thoughts about the primary and secondary material at hand. You want to do this as close to the moment of having the thought as possible, and you want to minimize anything that hampers this objective. Make your journal accessible and easy to use. Don't worry about correct spelling or punctuation. The journal is not for anyone's eyes but your own. The journal should document the ways you are thinking about the material and connecting it up with other things you've thought about.