Printer system

1 . A printer system comprising:

a plurality of printing mechanisms;

a paper inversion mechanism that inverts a paper between the printing mechanisms;

a paper buffer that adjusts a time lag in a synchronous operation performed by the printing mechanism; and

a controller that receives print data from a host computer, and synchronously operates the printing mechanisms to perform double-strike printing or double-sided printing,

wherein the controller includes:

a unit that measures a length of a paper path extended between the printing mechanisms in accordance with an installation state of the printing mechanisms, and enters a setup value to perform error recovery printing;

an image buffer that stores an amount of data equivalent to a distance from an image transfer point of a first printing mechanism to a fixing point of a last printing mechanism;

a pointer function that indicates a location of image data and a location of data in the image buffer, the image data being actually transferred during printing; and

a function that employs the pointer function to calculate a range for error recovery printing and performs the error recovery printing, when a malfunction, such as a paper jam, that requires the error recovery printing has occurred and when a paper is re-loaded.

2 . The printer system according to claim 1 ,

wherein the image buffer has a ring structure according to which, during printing, print image data is stored in the image buffer, and when memory is full, data at a head of a memory address is overwritten and data storage is continued.

3 . The printer system according to claim 1 , further comprising:

a function that manages a pointer in the image buffer, so that a maximum value for the length of the paper path extended between the printing mechanisms is obtained in advance as a margin, the length of the paper path being changed through a paper re-loading operation after removal of an error.

4 . The printer system according to claim 1 , further comprising:

a unit that enters a distance from the fixing point of the last printing mechanism to a discharge port of a printing post-processor, as the range for the error recovery printing,

wherein the error recovery printing is performed at a distance equivalent to a length that has been extended.

5 . The printer system according to claim 1 ,

wherein execution of the error recovery printing is selectable, after an error that occurred during printing is removed.

6 . The printer system according to claim 1 ,

wherein a time for deleting, from the image buffer, image data for pages that have been printed is defined as a time when it has passed a point obtained by tracing back from an image expansion start point a distance equivalent to a total of a maximum permissible paper path length and an unfixing range that is determined in accordance with an internal structure of each of the printing mechanisms.

7 . The printer system according to claim 1 , further comprising:

a unit that changes the printing mechanisms between an a synchronous state and a synchronous state based on an operator input instruction, the printing mechanisms being performing synchronous printing.

8 . The printer system according to claim 1 , further comprising:

a unit that sets the length of the paper path extending between the printing mechanisms.

9 . The printer system according to claim 1 , further comprising:

a unit that enables blank printing for an arbitrary number of pages by employing an operator panel sub-screen provided in an a synchronous state.