• Code: E020-0020
• Description: Error in the developing assembly (toner fault: ATR error)
  Indicates that the patch level is lower than the lower limit of the target although setting it as the maximum when initializing Yellow ATR.
• Remedy: Clean the ATR sensor window. Check the mounting of the developing assembly. Check the ATR sensor open circuit. Replace the ATR sensor.

• Code: E020-0021
• Description: Error in the developing assembly (toner fault: ATR error)
  Indicates that the patch level is lower than the lower limit of the target although setting it as the maximum when initializing Magenta ATR.
• Remedy: Clean the ATR sensor window. Check the mounting of the developing assembly. Check the ATR sensor open circuit. Replace the ATR sensor.

• Code: E020-0021
• Description: Error in the developing assembly (toner fault: ATR error)
  Indicates that the patch level is lower than the lower limit of the target although setting it as the maximum when initializing Magenta ATR.
• Remedy: Clean the ATR sensor window. Check the mounting of the developing assembly. Check the ATR sensor open circuit. Replace the ATR sensor.

• Code: E020-0022
• Description: Error in the developing assembly (toner fault: ATR error)
  Indicates that the patch level is lower than the lower limit of the target although setting it as the maximum when initializing Cyan ATR.
• Remedy: Clean the ATR sensor window. Check the mounting of the developing assembly. Check the ATR sensor open circuit. Replace the ATR sensor.

• Code: E020-0023
• Description: Error in the developing assembly (toner fault: ATR error)
  Indicates that the patch level is lower than the lower limit of the target although setting it as the maximum when initializing Black ATR.
• Remedy: Clean the ATR sensor window. Check the mounting of the developing assembly. Check the ATR sensor open circuit. Replace the ATR sensor.

• Code: E020-0100
• Description: Error in the developing assembly (toner fault: ATR error)
  Measured density value of patch for Yellow is higher than the upper limit.
• Remedy: Check the toner leakage from the toner buffer block within the developing assembly. Replace the patch image reading sensor.

• Code: E020-0101
• Description: Error in the developing assembly (toner fault: ATR error)
  Measured density value of patch for Magenta is higher than the upper limit.
• Remedy: Check the toner leakage from the toner buffer block within the developing assembly. Replace the patch image reading sensor.

• Code: E020-0102
• Description: Error in the developing assembly (toner fault: ATR error)
  Measured density value of patch for Cyan is higher than the upper limit.
• Remedy: Check the toner leakage from the toner buffer block within the developing assembly. Replace the patch image reading sensor.