Is your printer doing bad gradient 24/7 ?
Check your original output file first, and reexam your file, or do simple test by print on different printer if available. Sometime it may just be the gradient bitmap itself causing that. Or resample your gradient, and export them as tiff with higher bits and reprint. Some RIP engine do get confuse with eps files; tiff files usually more forgiven. Some gradients once it's enlarged from original size, it may cause pixels information on your final output file to be undesirable due to rasterization. Do all your gradients in high resolution when you didn't use vector base software to create gradient, but factor your size dimension to just inches to keep file size manageble, then once gradients applied, enlarge back to actual size but using Photoshop will limit your enlargement method to bicubical calculation which is o.k. but not super sharp. If you create your gradient in vector base software, u can import the EPS gradient into photoshop and assign it as 150dpi, but artwork of actual size and let photoshop rasterize the eps gradient for u, and then export as tiff to send to you rip. Most RIP engine convert vector to bits rate anyway, so to prevent hard gradient block convert to tiff is one option. Besure to assign color profile and color mode correctly to your file from input to enlarge to output. Inkjet printer do well at 150dpi for large size prints even 100dpi with good dither setting on your RIP, dither type of error diffusion seems universal, 720x720 resolution rip should be ideal for quality gradient file(s). How you execute/applied your gradient to the artwork, and RIP setting is critical for smooth gradient output. Photoshop, Illustrator, Flexsi, Corel Draw, these software generate gradient differently and using different save method, so when you converting to output it can get a little tricky! Think of inkjet printer as a spray paint head, how it spray and what it want to spray is the user's limit and setting. Funny thing is that the advertise of RIP engine doing 16bits rendering, isn't that meaning the rip can do it faster but not necessary clearer? At least not clearer on all file type! or perhap only certain file type for that matter!