Method and system for printing a pair of images on opposite sides of a sheet

A printing method for printing first and second images on opposite sides of a recording sheet by manually setting the recording sheet twice in a printer that prints images based on electronic image data, the printing method comprising the steps of:

• printing the first image on a first side of a recording sheet;
• providing indicia on the recording sheet to indicate the direction of the first image on the recording sheet, before printing the second image on a back side of the recording sheet from the first side;
• detecting the indicia from the recording sheet when the recording sheet is set in the printer for printing the second image on the back side;
• judging based on the detected indicia whether the back side of the recording sheet is oriented for printing or not, as well as whether the recording sheet is in a designated direction for printing the second image in a proper direction with respect to the first image;
• giving a warning without printing any image when the back side is not oriented for printing;
• and
• printing the second image on the back side when the back side is oriented for printing, wherein if the recording sheet is not in the designated direction, the image data of the second image is processed to turn the second image relative to the recording sheet so as to print the second image in the proper direction.

A printing system for printing first and second images on opposite sides of a recording sheet by manually setting the recording sheet twice in a printer, the printing system comprising:

• a printing device included in the printer, for printing an image on one side of a recording sheet based on electronic image data;
• a device for providing indicia on the recording sheet to indicate the direction of the first image on the recording sheet, before printing the second image on a back side of the recording sheet from the first side;
• a detection device for detecting the indicia from the recording sheet when the recording sheet is set in the printer for printing the second image on the back side;
• and
• a control device for judging based on the detected indicia whether the recording sheet is set in a proper posture or not, and causing the printing device to print the second image on the back side when the recording sheet is in the proper posture.