I'm sorry to hear about the issue that you're experiencing. I haven't had a chance to use the Kyocera Ecosys M5526cdw, but I was able to locate the user manual online. It looks like there are some additional troubleshooting options available that may improve your print results.
For reference, the link to the user manual is below:
Kyocera Ecosys M5526cdw User Manual- You mentioned adjusting the the paper type, but further adjustments may be possible with the custom media type settings. The manual indicates that the default media type settings have a specific paper weight assigned to them. For the "Labels" media type, the default weight is listed as "Heavy 1" which equates to a range of 106 gsm to 135 gsm. We typically recommend approximately 177 gsm for our weatherproof polyester material, so that "Heavy 1" setting may be a little bit light. According to the manual, you can use one of the custom media type settings to select "Labels" and "Heavy 3". The "Heavy 3" paper weight equates to a range of 164 gsm to 220 gsm, which should ultimately produce better results. More information can be found on page 8-15 of the manual.
- It looks like the printer has a variety of different density settings. Increasing print density should help provide a darker, more uniform background color on your labels. You can find instructions for the general density setting on page 6-11 and background density on page 6-23 in the manual.
- Check to see if the EcoPrint setting is enabled. If so, disabling EcoPrint can result in an improvement to overall print quality as well. Please check page 8-16 for instructions on the EcoPrint setting.
- The troubleshooting section in the manual lists a few additional settings and maintenance options that can help with print quality issues. The Color Registration Procedure (page 10-29), Drum Refresh (page 10-34), Calibration (page 10-34), and Laser Scanning Cleaning (page 10-34) options are all suggested for various print quality inconsistencies. The manual also recommends adjusting the Sharpness setting (page 6-22) if you're dealing with any kind of blurriness in your printed image.
I hope this helps. If you need any additional information please just let us know.