Whats wrong with my rice cooking process in my Zojirushi?
Based on your description, you seem to be measuring the rice and water in a measuring cup and adding them to the pan. Having used the same Zojirushi rice maker for 8 years, I can testify that relatively small variations in the water/rice ratio can produce large changes in the final texture of the rice. In your case, it seems to be that you're using too much water. Adjusting the ratio to 1:1 should give you a chewier baseline to work with, and adding water in 1 oz. increments should allow you very fine-grained control (no pun intended) over the texture of the rice.

That said, I believe that the most reliable results come from using the 3/4 C / 180 mL "cup" provided. To use it, you scoop a number of "cups" of rice and add them to the cooking pan, washing in the pan. After pouring off the wash water, fill the pan with water to the line on the inside face corresponding to the type of rice used and the number of "cups" of rice you added to the pan. In my experience, using this method produces essentially perfect results every time. Adjusting the water level to very slightly below the line will yield chewier rice, while adjusting slightly above will yield mushier rice.