There was once a teacher at my old HS, and people "thought" he was a perve or something. It was based on one rumour, which became bigger and bigger (because some people disliked the guy). It became routine for people to refer to him as "the perve".
I understand what you mean. I have not witnessed the inappropriate acts myself, but I go to a girl's school and because of that, the girls are more conscious and sensitive around male teachers. Students have seen him clicking out of xxx sites and seen it on his tabs. Of course I do not trust these rumours completely but the fact that they existed in the first place means something happened. This was not why I wanted to report him in the first place. He generally does not teach the class. All he tells us is to copy notes, read them ourselves, complete worksheets (without teaching us the content first) and go on Education Perfect. Most of my classmates learn mostly from education perfect then the teacher himself. Education Perfect is meant to be a tool used to ASSIT with understanding and consuming the information not replacing the teacher.
Just recently, he uploaded worksheets online (like always) and told us to complete it. He did not teach us this content beforehand, we basically guessed 'fill in the banks'. The worksheets are never printed out for us so I asked him:
'Could you print this out for us? Because I prefer to handwrite'
Him: 'No, you complete it on the doc'
My friend: 'it costs money for us'
Him: 'same for me'
Me: 'is that why you won't print it for us?'
Him: 'you print it out yourself.'
So. I had to print it out myself.

This really pissed off me off, I have never had a teacher be so rude. He did not give a reason why he would not print it off, apart from it 'costs money'–it does not cost money for teachers and even if it does, it's cheaper. Teachers are meant to print for students when requested or give a reason, like 'sorry I'm busy right now.'
I think it's important to note that teachers are humans too, and they attend school daily to receive an income and support themselves, their families etc. You need to be absolutely certain that this teacher is acting inappropriately (or has acted inappropriately), rather than grape vine or rumour chatter that you have heard. This is somebody's life we are talking about and a false report can be detrimental.
Thank you for sharing your perspective as a teacher. Many teachers that are old are only doing it purely for money. It is hard to find a job especially when your old. He will also get more pay after he retires. I'm not entirely sure how the system works. My teacher is very old and he puts very little effort in teaching us, as I mentioned above, all we do in class is copy notes and read off the board. Our average test marks as a class is also very low, under 50%. This goes to show how much we're understanding from he's method of teaching.
If you can, you can try talking to your house deans, the guidance counsellor or any teacher in general. They will take time to listen to your concerns (hopefully they don't start questioning you and blaming you like my teachers did). What you're doing is good and it's better to take the initiative than doing nothing at all 
Thank you for sharing your story! It's inconsiderate how they always blame the students, that's why many don't report. Seeing as though that's the case, then they should know when a student reports it is a serious problem and it matters to them. Students actually have a higher ranking status than the teachers but they manipulate you to feel as though your the problem. That's why I really look up to the MacRob student that left poop in the girl's bathroom to protest about this crap teacher😂
Here is the link to the article:
http://www.news.com.au/national/victoria/news/students-at-prestigious-melbourne-school-posts-note-explaining-why-she-defecated-on-bathroom-floor/news-story/80f5ed140d105d685e1f167a494af6aeI hope this makes more students stand up to themselves.