JP2692073B2 - Printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer that receives image data from a data processing device such as a host computer and prints on both sides of a sheet based on the image data. 2. Description of the Related Art A laser printer forms a latent image by pixels on a photosensitive drum by laser light deflected by a polygon mirror that rotates at high speed, obtains a visible image by a toner phenomenon, and transfers it to plain paper. After that, fixing is performed, and since the laser light can be modulated at high speed, high-speed and high-quality (high-density) printing and graphic recording can be realized. Therefore, the laser printer has a wide range of applications as an output device of various data processing systems and image processing systems using computers. On the other hand, there is an increasing demand for double-sided printing in which printing or copying is performed on both sides of the paper in order to effectively use the filing space in office work and reduce paper costs.
The simplest method of performing double-sided printing by a laser printer is, for example, after printing the first page on the surface of the fed paper and then reversing the paper in the paper circulation path in the laser printer, This is a method of printing the second page on the back side of the paper. But according to this method,
Since the circulation path is very long as compared with the paper, it takes a long time to reverse the paper and it takes a lot of time for printing. In order to eliminate this drawback, multiple sheets of paper in the circulation path,
For example, three sheets of paper can be simultaneously distributed, and the first page, the third page, and the fifth page are sequentially printed on the front surface of each sheet, and then the second, fourth, and fifth pages are printed on the reverse side of each sheet. A method of sequentially printing 6 pages has been proposed. However, the number of sheets existing in the circulation path varies depending on the individual printers, and even in the same printer device, the processing time of the character image processing device for controlling the printing unit varies depending on the content to be processed, As a result, the number of sheets in the circulation path is also different. As described above, since the conditions for printing differ depending on the individual printer device and its usage state, it is very complicated to control the order of pages of the image data to be transferred on the host computer side, and in practice It is impossible. It is also possible to transfer the image data from the host computer side in page order and temporarily store the data to be printed on the back side of the paper on the printer side. This requires a large image memory on the printer device side, which increases the cost of the printer device. The present invention has been made in view of the above-described problems, and in a printer that performs double-sided printing based on image data, it is possible to perform efficient printing with a short printing time and to prevent cost increase. With the goal. A printer according to a first aspect of the invention receives a series of image data over a plurality of pages twice in ascending or descending order, and one of the two data receptions is an even number. A printing unit for performing printing corresponding to each image data of the page, the other one for the odd number of pages, and a storage unit for sequentially accumulating a plurality of sheets on which one-sided printing is performed corresponding to the first data reception. In order to perform printing corresponding to the second data reception on the back surface of the sheets accumulated in the accommodating section, the accommodating section automatically performs the printing immediately after the printing corresponding to the first data reception is completed. And a re-feeding means for re-feeding. A printer according to a second aspect of the present invention performs printing of image data of odd-numbered pages in the first data reception,
The image data of even-numbered pages is printed in ascending order at the data reception of the first time. In the printer according to the invention of the present application, the printing unit prints a series of image data over a plurality of pages from a data processing device such as a host computer in ascending or descending order.
The data is received once, and the printing means performs printing corresponding to the image data, one of the two data receptions, one of the even pages and the other one of the odd data. The sheet re-feeding unit includes a storage unit that sequentially stores a plurality of sheets that have been single-sided printed in response to the first data reception, and
In order to perform printing corresponding to the second data reception on the back surface of the sheets accumulated in the accommodating section, immediately after the printing corresponding to the first data reception is completed, the sheet is automatically re-fed from the accommodating section. To do. 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. In the figure, 2 is a photoconductor on which a latent image is formed by a laser beam, 3 is a charging charger for giving a uniform charge to the photoconductor 2, and 4 is a developing device for developing the latent image formed by the laser beam. Reference numeral 5 is a transfer charger for transferring the developed toner onto the sheet, 7 is a cleaner blade for collecting the residual toner after the transfer, and 6 is a charging charger 3.
The eraser that irradiates to remove the residual charge to make the charging even in 8 is a paper cassette that stores paper,
Reference numeral 9 is a paper feed roller for guiding the paper to the conveyance path, and 10 is for 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 thereto is the sub-scanning direction) A registration roller that determines the recording position, 11 is a fixing roller that fixes the toner transferred by the transfer charger 5 onto the paper, and 12 is a discharge roller. 13a, 13b
Is a gate claw, and these gate claws 13a and 13b switch the path for discharging the paper to either the upper or lower discharge trays 14 and 15, and re-feed the discharged paper. Provides guidance for leading to the paper stacker 16. The re-feed stacker 16 is for temporarily accumulating a large number of sheets that have been single-sided printed to reflect the front and back sides of the sheets, and re-feeding these sheets to the photoconductor 2 in order from the bottom.
A lifting member (not shown) moves the storage position shown by the broken line in FIG. 1 to the re-feed position shown by the solid line. A re-feeding roller 18 is in contact with the lower surface of the accumulated sheets. 20 is a guide roller. The scanning optical system 21 includes a laser diode, a polygon mirror, a lens, a mirror, and the like, and is a known system in which laser light modulated according to an image signal scans the photoconductor 2. In the laser printer 1 described above, the paper P in the paper cassette 8 is sent out by the paper feed roller 9, transferred to one side by the photoconductor 2 and then fixed by the fixing roller 11, and guided by the gate claws 13a and 13b to the lower stage. However, a sensor (not shown) detects the trailing edge of the sheet P immediately before the trailing edge of the sheet P passes through the sheet ejection tray 12, and the gate pawls 13a and 13b are moved to the positions indicated by the solid lines in FIG. From the discharge roller to the position of the broken line
12 is reversed, and the paper P enters the refeed stacker 16 at the storage position (position shown by the broken line) by the guide roller 20,
Accumulated here. At the time of re-feeding, the re-feeding stacker 16 is lifted to the paper feeding position (position indicated by the solid line) by a lifting member (not shown), and the re-feeding roller 18 is rotated so that the re-feeding roller 18 is sequentially loaded from below the paper. And is transferred to the opposite side of the paper to perform double-sided printing. FIG. 2 is a block diagram of a double-sided printing system.
The host computer 30 generates image data of multiple pages,
This is transferred to the laser printer 1 together with the control data according to a fixed procedure. On the laser printer 1 side, the host interface unit 41 temporarily stores the data transferred from the host computer 30 in page units,
The control unit 42 controls the print engine 44 by the control data of these data and transfers the image data to the image data processing unit 43. The image data processing unit 43 transfers the bit data of the image processed in synchronization with the operation of the print engine 44 to the print engine 44. The print engine 44 modulates the laser diode of the scanning optical system 21 for printing, and controls the feeding and re-feeding of the paper P based on the control data from the control unit 42 and other printing. Perform the controls and actions required to do so. Now, the image data to be printed is transferred from the host computer 30 twice in order from the first page, but the laser printer 1 does not print an odd number of pages on one side of the paper fed from the paper cassette 8 at the first time. Only the image data is sequentially printed, and these are once stored in the refeed stacker 16. In the second time, the laser printer 1 feeds the paper from the re-feeding stacker 16, prints the image data of even pages on one side of each of these papers, and then discharges it to the upper discharge tray 14. FIG. 3 shows a flow chart of the control unit 42 for performing the above-mentioned printing operation. In FIG. 3, it is determined in step # 1 whether or not double-sided printing is to be performed. If NO, a routine for single-sided printing is executed, and if YES, steps # 2 and thereafter are executed. The flag N is set to zero in step # 2, and the variable P is set to zero in step # 3. Data for one page is transferred in step # 4, and the variable P is incremented by 1 in step # 5. In step # 6, it is determined whether the flag N is zero. When it is determined in step # 7 that the variable P is an odd number when the flag N is zero, data processing (step # 9) and printing (step # 10) are performed, and then the sheet is fed to the refeed stacker 16. When they are accumulated (step # 12) and it is determined that the variable P is an even number, these processes are not performed. The above processing is continued until it is determined in step # 14 that the first data transfer is completed. The paper at this time is fed from the paper cassette 8. When the data of the first transfer is completed (step # 1
4) Re-feeding sticker 16 in preparation for the second data transfer
Is switched to re-feed the paper (step # 16), the flag N is set to "1" (step # 17), and the process returns to step # 3. In the second processing, since the flag N is not zero, the result in step # 6 is NO, and when the variable P is an even number, data processing (step # 9) and printing (step # 10) are performed, and the paper is discharged to the tray 14 (Step # 13). When the variable P is an odd number, these processes are not performed. When it is determined in step # 14 that the second data transfer has ended, the refeed stacker 16
If the paper remains inside, it is discharged (step # 18, step # 19), and the process ends. Step # 18
The processing of step # 19 is to prevent the final page of the entire data transferred from being left in the refeed stacker 16 when the final page is an odd page. In the image data processing unit 43, the control unit
By the control from 42, the image data of the odd-numbered page is processed so as to be upside down from the image data of the even-numbered page. Match the direction. The paper discharged to the discharge tray 14 is printed so as to be pages 1, 2, 3, ... From the bottom, and the subsequent page alignment is unnecessary. When the printing of a plurality of copies is required, the above operation is repeated. According to the above-described embodiment, the laser printer 1 prints on the basis of the data at high speed by simply transferring the data twice from the host computer 30, and the double-sided printing is performed in the state where page alignment is performed. To finish.
Therefore, the host computer 30 can easily transfer data, the laser printer 1 can perform high-speed printing, and the time required for double-sided printing can be significantly reduced, and the image data sent from the host computer 30 can be stored. Since the image memory for this is sufficient for one page, the cost does not increase. In the above-mentioned embodiment, the data transfer of all pages of data is performed twice from the host computer 30, but the host computer 30 or the laser printer 1 determines whether it is an even page or an odd page, and the first time is an even page. By not transferring the data of each odd-numbered page for the second time, the waste of transferring the data of all pages can be eliminated.
Further, various sheet passing paths can be adopted for reversing the sheet in the laser printer 1. According to the present invention, data transfer in a data processing device such as a host computer is easy, and the time required for printing in a printer device such as a laser printer is short. Therefore, the utilization efficiency of the data processing device is improved and efficient double-sided printing can be performed. In addition, the sheet re-feeding unit includes a storage unit that sequentially stores a plurality of sheets on which one-sided printing has been performed in response to the first data reception, and the sheet re-feeding unit stores the second side with respect to the back surface of the sheets stored in the storage unit. In order to perform the print corresponding to the data reception of, the paper is automatically re-fed from the accommodating unit immediately after the print corresponding to the first data reception is completed, and thus the image memory having many pages is unnecessary. It is possible to keep the cost of the printer device low. Moreover, since there is no need for user intervention during double-sided printing, it is possible to realize convenient double-sided printing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows 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 shows processing contents of a control unit. It is a flowchart. 1 ... Laser printer, 8 ... Paper cassette, 14,
15 …… Output tray, 16 …… Refeed stacker, 30 …… Host computer, 42 …… Control section.

Continuation of front page    (56) References JP-A-58-51172 (JP, A)                 JP-A-60-73636 (JP, A)                 JP-A-61-185470 (JP, A)                 JP-A-61-289420 (JP, A)                 JP-A-63-84954 (JP, A)                 JP 62-186277 (JP, A)                 JP 62-42866 (JP, A)                 JP-A-63-247041 (JP, A)

Claims (1)

(57) [Claims] A series of image data over a plurality of pages is received twice in ascending or descending order, and one of the above two data receptions corresponds to the even page and the other corresponds to the image data of the odd page. The printer includes a printing unit that prints and a storage unit that sequentially stores a plurality of sheets that have been single-sided printed in response to the first data reception. A printer comprising: a paper re-feeding unit that automatically re-feeds paper from the storage unit immediately after the printing corresponding to the first data reception is completed to perform printing corresponding to data reception. 2. The printer according to claim 1, wherein the printer receives odd-numbered pages of image data when the first data is received, and prints even-numbered pages of image data in ascending order when the second data is received.