1. Field of Invention
The present invention relates to a printing device that prints on both sides of a print medium and has a page mode for converting one page of print data after setting front and back side print data conversion areas in a data storage device, and to a control method for the printing device.
2. Description of Related Art
Printing devices (simply “printers” below) for printing on both sides of paper or other print medium (commonly called “duplex printing”) are taught in Japanese Unexamined Patent Appl. Pub. JP-A-03-027434 and Japanese Unexamined Patent Appl. Pub. JP-A-04-001067.
Japanese Unexamined Patent Appl. Pub. JP-A-03-027434 and Japanese Unexamined Patent Appl. Pub. JP-A-04-001067 teach a printing system that has a repagination unit, an odd-page processing unit, an even-page processing unit, and a reverse-side print processing unit. The repagination unit repaginates and updates the page numbers when a duplex printing command is issued by the host computer. The odd/even page determination unit determines whether a page number is odd or even. If the page number is odd, the odd-page processing unit prints on the front of a sheet and then discharges the sheet into an intermediate holding tray. If the page number is even, the even-page processing unit writes the start address and length of the even page print command string to a control table. The reverse-side print processing unit prints the even pages on the second side of the sheets on which the odd pages have been printed on the first side and are stored in the holding tray.
The host computer issues a duplex printing command to the printing system in order to print on both sides. More particularly, a command must be asserted from the host computer in order to switch between simplex printing and duplex printing. Printers that switch between duplex printing and simplex printing according to the on or off state of a DIP switch are also known from the literature. If the storage capacity of the intermediate holding tray is exceeded during the first-side printing process or the end of a single-sided document is detected when the duplex printing mode is active, operation switches from the first-side printing process to the second-side printing process.
Printers that print to continuous paper such as roll paper are also known. When such printers are used for printing sales receipts to roll paper, the length of the printed data is not constant and the length of each issued receipt varies with each sale transaction. The issued receipt is long when there are many purchased products and there is much information to print, and is short when there are few products (little information). If the roll paper printer can print on both front and back sides of the roll paper and can print long receipts in the duplex printing mode, the length of the issued receipt can be shortened and roll paper consumption can be reduced.
One type of printer used for printing receipts is the line thermal printer. In general, each time a line thermal printer receives print data including one line of print data and a carriage return, it prints the one line and then advances the paper one line. If a carriage return is not included but print data exceeding one line is received, the printer also executes the printer process and advances the paper. One page (one receipt) is printed and output by repeating these steps. This printing process mode is referred to herein as the “standard mode.”
Demand for printing receipts and coupons having a greater visual impact on the customer has also grown in recent years. Printers with a wide range of print functions, such as for printing logos, images, and barcodes in addition to text data, and changing the output format by changing the print orientation (page orientation), are also common. In order to provide such diverse printing functions, line printers that have a page mode enabling printing a free-form layout in addition to the standard mode described above are also known from the literature. When the page mode is selected, a prescribed printing area is set in a buffer (memory) enabling converting print data (that is, conversion to data enabling printing by the print head) for at least one full page, all of the print data is converted into the set printing area, and a start printing command is then asserted to start a batch printing process to print all of the data in a single process (print the converted print data by the print head).
Thus setting the printing area enables freely arranging the layout of the print data in the set printing area during conversion. For example, a horizontal layout in which the normal print orientation is horizontal (across the width of the page) can be converted to a vertical layout in which content is printed in the paper feed direction by rotating the print data 90 degrees in the print buffer when converting the print data. The page mode thus enables print functions such as page layouts that cannot be printed in the standard mode, and thus enables more effective receipt printing.
When a printer capable of duplex printing prints both sides, it is also desirable to shorten the length of the issued receipt and reduce paper consumption even when operating in the page mode. In duplex printing, however, the print result is affected by how the first-side data and the second-side data are allocated to the front and back sides. For example, if the break between the first-side data and the second-side data occurs in the middle of an image, the image will be broken into two parts and a receipt or coupon that has a positive visual impact on the user cannot be printed.
If the print data is rotated 90 degrees to the vertical print orientation in the page mode, the desired print output cannot be achieved if one page of data in the printing area is distributed horizontally to the front and back sides. For example, when the data is converted for printing vertically, lines that are longer than the width of the coupon or receipt can be printed in the paper feed direction to one side of the print medium, but if the same data is printed horizontally, the printout will be split.