JPS63247041A - Perfect printing system - Google Patents

Abstract

PURPOSE:To enable efficient printing, by a system wherein one of two data transfers for transferring a series of image data for a plurality of pages starting from the top page to the last page and from the last page to the top page is used for printing the image data on even numbered pages, and the other is used for printing the image data on odd numbered pages. CONSTITUTION:Of image data to be printed, the data for even numbered pages are sequentially transferred from a host computer 30, starting from the top page (page 2), and are sequentially printed by a laser printer 1 on one side of each of papers supplied from a paper cassette 8. The papers thus printed on one side thereof are once stored in a paper-resupplying stacker 16. Of the image data, the data for odd numbered pages are sequentially transferred from the host computer 30, starting from the last page. When the page number of the first one to be printed of the odd numbered pages (namely, the last one of the odd numbered pages) is greater than the page number of the last one of the even numbered pages, a paper for the last odd numbered page is supplied from the cassette 8 in a printer 1. In other cases, the paper for the last odd numbered page is supplied from the stacker 16. The image data for the odd numbered pages are sequentially printed on one side of each of the papers for the odd numbered pages thus supplied, and the papers thus printed are discharged into an upper discharging tray 14.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to a printer that receives image data from a data processing device such as a host computer and performs double-sided printing using a printer device that has a paper refeed stacker. Regarding the double-sided printing system.

(Prior art and its problems) Laser printers form a pixel-based latent image on a photoreceptor drum using laser light deflected by a polygon mirror that rotates at high speed, and obtain a visible image by toner development to print on plain paper. Since the laser beam can be modulated at high speed, high-speed, high-quality (high-density) printing and graphic recording can be realized. For this reason,
Laser printers have a wide range of uses as output devices for various data processing systems and image processing systems using computers.

On the other hand, there is an increasing demand for double-sided printing, which prints or copies on both sides of paper, in order to effectively utilize filing space and reduce paper costs in office processing. The simplest method for double-sided printing with a laser printer is, for example, to print the first page on the front side of a fed sheet of paper, then turn the sheet over in the paper circulation path inside the laser printer and print the same sheet. This method prints the second page on the back side of the paper. However, according to this method, the circulation path is much longer than that of paper, so it takes time to turn the paper over, resulting in a long printing time.

In order to eliminate this drawback, it is possible to simultaneously circulate multiple sheets of paper, for example, three sheets, in the circulation path, print the third and fifth pages on the surface of each sheet, and then reverse the paper. A method has been proposed in which the second, fourth, and sixth pages are sequentially printed on the back side of each sheet. However, the number of sheets of paper that exists in the circulation path varies depending on each printer, and even for the same printer device, the processing time of the character image processing device for controlling the printing section varies depending on the content to be processed. As a result, the number of sheets of paper in the circulation path also differs. In this way, the conditions for printing differ depending on the individual printer devices and their usage conditions, so controlling the order of pages of image data to be transferred on the host computer side is extremely complicated and difficult in practice. It is impossible.

Another possible method is to transfer the image data to page 1+l/( from the host computer side, and temporarily store the data to be printed on the back side of the paper on the printer side, but this method does not allow There is a problem in that an image memory for several pages is required on the printer side, which increases the cost of the printer.

(Technical Means for Solving the Problems) In view of the above-mentioned problems, the present invention provides a double-sided printing system using a laser printer or the like, which enables efficient printing with less time required for printing, as well as cost-effective printing. The purpose is to prevent the increase in The technical means for this purpose is to transfer a series of image data spanning multiple pages to a data processing device by transmitting the data twice: data transfer in the order from the first page to the last page, and data transfer in the order from the last page to the first page. The image data is transferred from the image data to the printer device, and the printer device prints the image data of an even page in one of the two data transfers and the image data of an odd page in the other time. shall be.

(Operation) Data is transferred from the data processing device to the printer twice, one time starting from the first page and the other time starting from the last page. The printer device prints even-numbered pages on one side of the paper in one of the two data transfers, and prints odd-numbered pages on the other side of the paper in the other one.

At this time, the paper printed on one side is temporarily stored in the paper re-feeding stacker, and is re-fed to be printed on the other side.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the laser printer 1. FIG. In the figure, 2 is a photoreceptor on which a latent image is formed by a laser beam;
3 is a charger for uniformly charging the photoreceptor 2; 4 is a developer for developing a latent image formed by a laser beam; 5 is a transfer charger for transferring the developed toner onto paper; 6 7 is a cleaner blade that collects excess toner after transfer; 7 is an eraser that irradiates to remove excess charge in order to uniformly charge the charger 3; 8 is a paper cassette that stores paper; 9
is the paper feed roller that guides the paper to the conveyance path, and IQ is the recording on the paper in the sub-scanning direction (the direction in which the laser beam scans the paper is the main scanning direction, and the direction perpendicular to it is the sub-scanning direction). Registration roller for determining position, 11
2 is a fixing roller that fixes the toner transferred by the transfer charger 5 onto the paper, and ]2 is a discharge roller *13
a.

13b is a gate claw, and these gate claws 13a,
13b is the upper or lower output tray 14.1 for storing paper.
5, and guides the paper being discharged to the paper refeed stacker 16.

The paper refeed stacker 16 temporarily accumulates a large number of papers on which one-sided printing has been performed in order to reverse the paper, and refeeds these papers to the photoreceptor 2 in order from the top. 17 is an alignment member for aligning sheets; 1 is a refeed roller; 19
a lifting member 2 for lifting the paper accumulated in the paper refeed stacker 16 and bringing it into contact with the paper refeed roller 18;
0 is a guide roller.

The scanning optical system 21 is a known system that includes a laser diode, a polygon mirror, a lens, a mirror, and the like, and scans the photoreceptor 2 with a laser beam modulated according to an image signal.

In the above-mentioned laser printer l, the paper P in the paper cassette 8 is sent out by the paper feed roller 9, transferred onto one side by the photoreceptor 2, fixed by the fixing roller 11, and guided by the gate claws 13a and 13b to the lower stage. During this process, a sensor (not shown) detects that the trailing edge of the paper P is just before passing the discharge roller 12, and as a result, the gate claws 13a, 13
b switches from the solid line position to the broken line position in FIG.
The paper enters the paper refeed stacker 16 and is accumulated there. When refeeding paper, the alignment member 17 moves in the direction of arrow A to align the leading edge of the paper, and then the lifting member 1
The paper is lifted up by the paper refeed roller 18 and sent again toward the photoreceptor 2 by the rotation of the paper refeed roller 18, and is transferred to the opposite side of the paper, thereby performing double-sided printing.

FIG. 2 is a block diagram of a double-sided printing system. The host computer 30 generates multiple pages of image data,
This is transferred to the laser printer l along with control data according to a fixed procedure. On the laser printer 1 side, the host interface section 41 temporarily loads the data transferred from the host computer 30 page by page, and the control section 42 controls the print engine 44 using control data among these data. The image data is transferred to the image data processing section 43. In the image data processing section 43,
The bit data of the processed image is transferred to the print engine 44 in synchronization with the operation of the print engine 44. The print engine 44 performs printing by modulating the laser diode of the scanning optical system 21 described above, and also controls the feeding and refeeding of paper P and performs other printing operations based on control data from the control unit 42. Perform the necessary controls and operations.

Of the image data to be printed, the host computer 30 sequentially transfers even-numbered pages from the first page (second page), and the laser printer 1 prints each page on one side of the paper fed from the paper cassette 8. These image data are printed one after another and are temporarily transferred to the re-feed stacker 16.
Then, from the host computer 30,
Odd pages of the image data are transferred in order starting from the last page.

If the first page (i.e., the last page of odd-numbered pages) is larger than the last page of even-numbered pages, the laser printer 1 feeds paper from the paper cassette 8 for that page, and for the other pages. In this case, sheets are fed from the paper re-feeding stacker 16, image data of odd-numbered pages are printed on one side of each of these sheets, and then the sheets are ejected to the upper ejection tray 14.

FIG. 3 shows a flowchart of the control section 42 for performing the above-described printing operation.

In FIG. 3, it is determined in step #1 whether double-sided printing is to be performed, and if no, a routine for single-sided printing is executed, and if yes, step #2 and subsequent steps are executed. In step #2, data is transferred from the host computer 30, and if the data is an even page, N-1 is set; if the data is an odd page, N=0. If the data is an even number of pages, feed the paper from the paper cassette 8 (step #5), perform data processing (step #6) and print (step #7), and then re-feed the paper to the paper stacker 16. (Step #9). If the data is for an odd page, compare the sizes of the last page of the odd and even pages (step #13); if the odd page is large, compare the size of the first page (step #13).
Only the last page of odd-numbered pages is fed from the paper cassette 8 (steps #14, #5), otherwise the paper is re-fed from the paper re-feed stacker 16 (step #15), and the printed paper is It is discharged to the discharge tray 14 (step #10).

Note that the image data processing section 43 processes the image data of odd-numbered pages so that it is upside down from the image data of even-numbered pages under the control of the control section 42, thereby changing the direction of the image. The vertical direction is made to match the vertical direction of the paper that is re-fed from the stacker 16. The sheets discharged to the discharge tray 14 are printed with pages 12.3, . . . in order from the top, and subsequent page alignment is not necessary. If you need to print multiple copies, repeat the above operation.

According to the above-described embodiment, the host computer 30 transfers data twice, from the first page of even-numbered pages and from the last page of odd-numbered pages, so that the laser printer l can print data at high speed based on the data. and completes double-sided printing with page alignment completed. Therefore, the host computer 30 can easily transfer data, and the laser printer 1 can print at high speed, greatly reducing the time required for double-sided printing, and can also store image data sent from the host computer 30. Since the image memory for one page is sufficient for this purpose, the cost will not increase.

In the above-described embodiment, the host computer 30 performs two data transfers by distinguishing only even-numbered pages and only odd-numbered pages, but without making such a distinction, all pages are transferred both times. The control unit 42 of the laser printer 1 may determine whether the page is an even page or an odd page, and the odd page may be ignored when transferring from the first page, and the even page may be ignored and not printed when transferring from the last page. This further simplifies the data transfer process on the host computer 30 side. Furthermore, in the above embodiment, the data for even-numbered pages is transferred first, but it is also possible to transfer data from the last page of odd-numbered pages first, and then transfer data from the first page of even-numbered pages. be. Further, various paper passing paths can be adopted for reversing the paper within the laser printer 1.

(Effects of the Invention) According to the present invention, it is easy to transfer data with a data processing device such as a host computer, and the time required for printing with a printer device such as a laser printer is short. This improves efficiency and enables efficient double-sided printing. Moreover, there is no need for an image memory for many pages, and the cost of the printer device can be kept low.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a front sectional view of a laser printer, FIG. 2 is a block diagram of a double-sided printing system, and FIG. 3 is a flowchart showing processing contents of a control unit. ■...Laser printer (printer device), 8...Paper cassette, 14.15...Ejection tray, 16.
. . . Paper refeeding stacker, 30 . . . Host computer (data processing device), 42 . . . Control unit.

Claims (3)

[Claims] (1) A data processing device that generates multiple pages of image data, and a paper refeed stacker that stores and refeeds multiple sheets of paper that have been printed on one side in order to reverse the paper, and the said data In a double-sided printing system that includes a printer device that performs double-sided printing of image data transferred from a processing device, the data processing device transfers a series of image data spanning multiple pages in the order from the first page to the last page. The data is transferred to the printer device by two data transfers, one in the order from the last page to the first page, and one of the two data transfers is performed on an even-numbered page. A double-sided printing system characterized by printing image data for each odd-numbered page. (2) The printer device prints image data of odd-numbered pages when data is transferred from the first page, and image data of even-numbered pages when data is transferred from the last page. double-sided printing system. (3) When printing the image data of the last page of the odd-numbered pages, if the page number is greater than the number of the last page of the even-numbered pages, refeeding from the paper refeeding stacker is performed. 3. The double-sided printing system according to claim 2, wherein a new sheet of paper is fed without any interruption.