I bought a Konica Minolta DiMAGE Z5 second-hand, and it didn't have a lens cap.
I looked here on Thingiverse and didn't find one, so I made this quick one in Fusion.
I find it easiest to take off when the camera is turned on and the lens is extended.
It should fit on other cameras from the Z-series.
Since this is press fit, and all printers print a bit differently, you might need to scale it a tiny amount if your first print doesn't fit snugly.
Konica_minolta_z5_lens_cap.stl | 155.4KB |