Abstract: An example printing fluid pen comprises a plurality of fluid ports, including an inlet port to direct fluid from a fluid reservoir to a fluid ejection device, and a recirculation port to direct fluid from the fluid ejection device out of the inkjet pen. The example pen also includes a plurality of parallel fluid pressure regulators fluidly coupled with the inlet port, each of the plurality of parallel fluid pressure regulators to receive fluid from the inlet fluid port.

Abstract: A fluid ejection system may include a first fluid ejection module and a second fluid ejection module. The first fluid ejection module may include a first end, a first module face and a first row of first ejection heads having first ejection faces along the first module face. The second fluid ejection module may include a second end opposite the first end, a second module face and second ejection heads having second ejection faces along the second module face. The first module face and the second module face are spaced by an inter-module mesoscale gap.