Z4MPLUS doesn't recognize the MEDIA(LABEL) automatically.

SOURCE: Zebra 105sl - printer does not print correct size

This can happen if you have the wrong dpi setup. For instance the 105sl can be either 203dpi or 300dpi. If your printhead is 300dpi and the label you create is expecting 203dpi, then you will see shrunken label. Your situation doesn't exactly sound like this is the case but it may be worth checking.

SOURCE: Zebra 105SL label issues

I am surprised that you are using that sequence of buttons to solve this problem. I am pretty sure that they want you to go into the "Media Sensor Calibration" setup in the config menu. It is a bit more complicated than what you have described. I also believe that the size of the gap on two of your labels might be out of tolerance (they are usually 1/8" gaps between the labels). The black marks are a problem for the transmissive sensors. You may need to move the transmissive media gap sensor (remember it has two parts: upper and lower). I would usually setup mine for a place beyond the black mark so that you are looking at just the white paper.

To start out:
1. Load the backing of a 6" strip of media (no label attached).
2. Remove a ribbon (if you usually use one).
3. Close the printhead.
4. Press SETUP/EXIT and then NEXT/SAVE until "Media and Ribbon Calibrate" appears.
5. Press "+" to start the calibration procedure. You should see the "Load Backing" in the LCD Display. You already have the backing loaded so continue to the next step.
6. Press "+" to answer the message and the next screen should say, "Remove Ribbon". You have also removed the ribbon.
7. Press the "+" to continue. You should see the screen say, "Calibrating Please Wait". After the sensors are setup by the machine a new screen should appear, "Reload All".
8. Open the printhead, and move the labels until they are loaded correctly to print. Smooth out the ribbon and load it correctly.
9. Withe media and ribbon now loaded, press "+" to continue and the machine should say, "Media and Ribbon Calibrate".
10. Press the Setup/Exit button once. It should say, "Save Changes Permanent". Press Next/Save to finish the process.
11. Do a normal calibration of your stock and print a label.

You are done. The machine will run for the labels you have setup the sensors for. Unfortunately, you must do this for each of the media types. To automate this, you could run a Configuration listing, capture the settings you just created for each type of label. Take these to a programmer to have them send the setup to the machine before the job. This is beyond the scope of this type support to really help you.

SOURCE: Zebra LP 2844 doesn't feed label all the way out

Hi Brian,
When the last label printed is still under the printhead, that means the printer is in "rewind mode". There should be an option for "tear off" mode in the printer driver. This is the mode that pushes the last label printed out to the tear bar. The printer will then "backfeed" when printing the next label. Peel off mode is used if you want to print a label and have it "peeled" off the liner so that you can just pick up the label off the liner and apply it. That takes the rewind option to be installed.
Watch out though, if you are using a label software package, there might be a setting in the label format setup for "tear off" which usually overrides the settings in the printer.

Hope that helps !