This is the
mitsuwari-ken-hanabishi (三つ割り剣花菱) crest, a rather obscure design used by the Aki Clan
(安芸氏) of (surprise, surprise) Aki Dstrict in the Tosa Province of Shikoku. The Aki Clan is said to be descended from Soga no Umako, a powerful minister in Ancient Japan whose descendants were later exiled from the capital after a power dispute in the royal court.
Roughly translated, the crest can be called the Three Split Sword Flower Diamond, although it certainly doesn't look like a diamond. It is a variation on the more general
hanabishi (i.e., flower diamond) crests, which are essentially diamond shapes composed of stylised flowers. This design originated as a decorative pattern, and has little deeper meaning. This is the first crest above.
One relatively common variation is to add highly stylised swords between the flower's petals. Known as 'ken hanabishi, i.e. "sword flower diamond", it is popular among the samurai families as a symbol for battle, martial virtues, and victory. The result looks like the second crest from the left above.
Another variation is to use multiple flowers and only show a part of each. This is called a
wari-hanabishi, or "split flower diamond". This can be done in a number of ways, such as the third and fourth crests above, which have two and three splits respectively.
mitsuwari-ken-hanabishi crest combines the two designs (swords and three splits).
jubako is probably only using this crest for decoration. As an unusual and relatively more elaborate crest, it is suitable for the
hanabishi's original role as a decorative pattern.