Coupling member and inkjet recording device

A coupling member comprising:

• a first member as a cylindrical body having a central axis extending in a predetermined direction, and having a liquid flowing passage inside, and
• a second member as a cylindrical body having the central axis configured to be connected to the first member in the axis direction, having the liquid flowing passage inside, so as to allow the liquid to flow in the axis direction together with the first member, wherein
• the first member has a plurality of engaging holes arranged with intervals in a circumferential direction, so as to be recessed in a radial direction from a circumference surface of the first member,
• the second member has a plurality of engaging protrusions arranged with intervals in the circumferential direction, so as to protrude in the radial direction from a circumference surface of the second member, the engaging protrusions being respectively inserted into the plurality of engaging holes in the radial direction, so as to be respectively engaged with the plurality of engaging holes in the axis direction,
• the plurality of engaging holes include at least one pair of first engaging holes and at least one pair of second engaging holes,
• the plurality of engaging protrusions include the same number of pairs of first engaging protrusions as the pairs of first engaging holes so as to respectively engage with the pairs of the first engaging holes, and the same number of pairs of second engaging protrusions as the pairs of the second engaging holes so as to respectively engage with the pairs of the second engaging holes,
• when one of the first member and the second member is inserted into the other in the axis direction, the first engaging hole and the first engaging protrusion are engaged with each other, while the second engaging hole and the second engaging protrusion are not engaged, and
• in the state where the first engaging hole and the first engaging protrusion are engaged with each other, the second member is displaced in the circumferential direction with respect to the first member, so that the second engaging protrusion reaches a position for engaging the second engaging hole, while maintaining the engagement between the first engaging hole and the first engaging protrusion, and hence the first member and the second member are connected to each other in the axis direction.