DDD entity constructor parameters

If you have an entity with a value object as an attribute.

Which would be the parameters of the entity constructor, the value object? Or the primitive types of the value object?

First I did it building the value object outside the entity and I passed the value object to the entity constructor... but then I realized that maybe it would be the entity itself that has to build the value object.

I thought this because the entity and the value object are in fact an aggregate, and it is supposed that you have to access the inside of an aggregate through the aggregate root, i.e., through the entity.

So which is the right way? Is it allowed to deal with the value object outside the entity? Or the value object just can be used by the entity?

Thank you.

EDIT:

For example, I have an entity "Task" that is the aggregate root. This entity has a value object "DeliveryDate" (in format "dd/mm/yyyy hh:mm"). The entity has more value objects too.

class DeliveryDate extends ValueObject {

    private String formattedDeliveryDate;

    private DeliveryDate() {
        super();
    }

    DeliveryDate ( String formattedDeliveryDate ) {
        this();
        this.setFormattedDeliveryDate ( formattedDeliveryDate );
    }

    private void setFormattedDeliveryDate ( String formattedDeliveryDate ) {
        << check that the string parameter "formattedDeliveryDate" is a valid date in format "dd/mm/yyyy hh:mm" >>
        this.formattedDeliveryDate = formattedDeliveryDate;
    }

    ........     

The entity constructor:

Task ( TaskId taskId, Title title, Delivery deliveryDate, EmployeesList employeesList ) {
    this();
    this.setTaskId(taskId);
    this.setTitle(title);
    this.setDeliveryDate(deliveryDate);
    this.setEmployeesList(employeesList);
}

My doubt is: Is this ok? (passing to the constructor the DeliveryDate object) Or should I pass the string? (and the constructor creates the DeliveryDate object)

I think it's more a question of "should the outside of the aggregate know about the DeliveryDate concept?"

In general my doubt is about any value object of any entity, not just Task and DeliveryDate (this is just an example).

I have asked the question about the constructor, but it's valid for factories too (if the process of creating an instance is complicated)... should the aggregate factory parameter be the value object? or the primitives to create the value object?