Your default printer driver may be set to a Black and White printer. Excel uses the default printer settings to create a high quality picture of tables or charts. Try the following:
• Close all Office programs
• Open Control Panel | Devices and Printers
• Change the default printer driver by right-clicking on a different printer and choosing Set as default printer
• Reopen the program.
Note: If you don’t have an option to select a suitable colour printer, you can choose Microsoft Print to PDF as your default printer.