To solve the following problems: actual printing results have to be seen when a user determines whether or not adjusting operations are required; and the printing results when the user determines that adjustment is required have a high probability of not having sufficient image quality.

An adjustment timing determining means computes timing requiring an adjusting mode, depending on printing output information from a printing performing means, status information from a status detecting means, and adjustment performance information from an adjusting performing means, and gives information on timing of requiring the adjustment, via an adjusting timing notification means.