Full view of Jupiter in infrared light
Jupiter’s heat is largely internally generated — not from the sun. So the bands you’re seeing is where heat is rising from the interior, while the cold bands have cooled due to losing heat to space (in the form of infrared).
There is some sunlight related heating, but Jupiter emits twice as much as it gets from the sun. There are some that propose that Jupiter has some limited amounts of fusion going on in the interior to sustain this, but it could also just be latent heat of formation or due to mineral phase changes (crystallization processes).