D3.js force directed graph, reduce edge crossings by making edges repel each other

So i have a page already which draws a force directed graph, like the one shown here.

And that works fine. I'm using the JS from here, with a few tweaks to spread out the nodes slightly nicer.

These are more or less the only differences:

d3.json("force.json", function(json) {
  var force = d3.layout.force()
      .gravity(0.1)
      .charge(-2000)
      .linkDistance(1)
      .linkStrength(0.1)
      .nodes(json.nodes)
      .links(json.links)
      .size([w, h])
      .start();

Where reducing the link strength seems to make the links more like springs, so it becomes similar to the Fruchterman & Reingold technique often used. This works reasonably well, but only for fairly small graphs. With larger graphs the number of crossings just goes up - as one would expect, but the solution it lands on is normally far from optimal. I'm not looking for a method to get the optimal solution, I know that's very difficult. I would just like it to have some crude addition that tries to force the lines apart as well as the nodes.

Is there a way to add a repulsion between in links, as well as between the nodes? I'm not familiar with the way D3 force works, and i can't seem to find anything that says this is possible...