JPH09216430A - Perfector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a perfector improved so as to allow throughput at a time of double-side, printing to approach that at a time of single side printing. SOLUTION: All of the data of one printing job sent from a host computer are accumulated in the disk memory device in a printer. Next, only the data of an odd-number page is read from the disk memory device to form the image of the odd-number page. The unprinted paper 2 on an input tray 3 is taken in and the image of the odd-number page is printed on the surface thereof and the surface printed paper is outputted to an intermediate tray 10. When the printing of all of odd-number pages is completed, only the data of an even- number page is read from the disk memory device to form the image of an even-number page. The surface printed paper 13 on the intermediate tray 10 is taken in and the image of the even-number page is printed on the rear surface thereof and the paper completed in double-side printing is outputted to an output tray 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus capable of printing on both sides of paper.

[0002]

2. Description of the Related Art A double-sided printing device disclosed in Japanese Patent Publication No. 6-53422, when one sheet is taken from an input tray,
First, print the image of the odd page corresponding to the surface of the paper,
Then, the sheet is turned upside down (the sheet is turned upside down accordingly), and the sheet is discharged to the intermediate tray. After that, the same paper is taken in from the intermediate tray, the image of the next even page is printed on the back surface of the paper in the upside-down direction, and then discharged to the output tray. After that, the next sheet is taken in from the input tray, and the images of the subsequent odd-numbered pages and even-numbered pages are printed on the front and back surfaces in the same procedure. In this way, images of consecutive pages are printed in page order on the front and back surfaces of a plurality of sheets.

[0003]

One of the problems of the above-mentioned conventional printing apparatus is low throughput. That is, the work of reversing the paper is required after the printing of the odd page on the front surface of the paper is completed and before the printing of the next even page on the back surface is started. Moreover, this inversion work is
It occurs for each set of odd and even pages. Therefore, the throughput in double-sided printing is significantly lower than that in single-sided printing, which does not require reversing work.

Therefore, it is an object of the present invention to provide a double-sided printing apparatus improved so that the throughput in double-sided printing can be made closer to that in single-sided printing.

[0005]

The double-sided printing device of the present invention comprises a mass storage device such as a disk device. When a print job is received from the host computer, print request data for all pages included in the print job is stored in the mass storage device. Alternatively, the images of all pages created based on the print request data are stored in the mass storage device in an appropriate data format (for example, bitmap data, intermediate code, or compressed data). Further, this printing apparatus distinguishes all pages included in the print job into a front page to be printed on the front surface of the paper and a back page to be printed on the back surface, and prints a front page indicating the printing order of the front pages. The back page printing order indicating the order and the back page printing order is determined.

After that, the printing apparatus first creates an image of the front page in the front page printing order based on the information stored in the mass storage device, and gives it to the printing mechanism.
At the same time, the first paper feeding mechanism supplies unprinted paper to the printing mechanism. Therefore, the printing on the front surface of the paper is executed. The paper with the printed surface is stored in the second paper feed mechanism.

When all the front page images have been created, the printing device then creates back page images in the back page printing order based on the information stored in the mass storage device and causes the printing mechanism to perform printing. Give this. In parallel with this, the second paper feeding mechanism supplies the paper on which the surface is printed to the printing mechanism. Therefore, printing on the back side of the paper is executed. When all the images on the back page have been printed, as a result, double-sided printing on all pages is completed.

According to the printing apparatus of the present invention, the printing on the front side is performed first, and then the printing on the back side is performed. Therefore, the sheet reversing operation for each sheet is not necessary. Therefore, the throughput is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic configuration of a mechanical portion of a print engine of a page printer capable of double-sided printing according to an embodiment of the present invention. The driver circuit of the illustrated mechanical elements is also included in the print engine, but the illustration thereof is omitted.

In the following description, one of the two sides of a sheet is referred to as the "front side" and the other side is referred to as the "back side" for convenience sake, but this is merely used for distinction. However, it has no further limiting meaning.

The recording unit 1 includes a photosensitive drum 11 and a transfer device 12.
In addition, the image data stored in an image buffer, which will be described later, is transferred to the sheet 2 as a toner image by using a known accessory not shown.

Sheets 2 of which both sides are unprinted are stacked on the input tray 3. On the input tray 3, the paper 2 is placed in such a posture that the surface thereof faces downward in the figure. The sheets 2 on the input tray 3 are sent out one by one from the uppermost one by the rollers 4 to the sheet feeding device 5. The paper carrying device 5 has a conveyance path 51 and a conveyance roller 52, and conveys one sheet of the fed paper to the recording unit 1. A paper sensor 6 exists in front of the recording unit 1 and detects the front edge of the paper.
In response to the detection signal from the paper sensor 6, the recording unit 1 activates the rotating drum 11 to transfer the corresponding page image in the image buffer as a toner image on the surface of the conveyed paper. At this time, the driver circuit of the recording unit 1 reads the page image from the data buffer in the direction from top to bottom and gives it to the recording unit 1, so that the upper end of the page image comes to the front end side of the paper. The fixing unit 7 is the recording unit 1.
Receives paper from and fixes the toner image on its surface. This completes the printing on the front surface of the paper.

A guide device 8 is provided at the exit of the fixing unit 7. The guide device 8 has an L-shaped arm 82 connected to an electromagnetic actuator 81. The base end portion 82a of the arm 82 is axially fixed at a fixed position, and the tip end portion 82a is
A sheet guide 83 is pivotally supported on b. Paper guide 8
3 is in contact with a fixed bar 84 for adjusting its posture. By the action of the actuator 81, the arm 8
2 swings around the base end portion 82a, and the paper guide 83 at the tip thereof changes its posture by the action of the fixing bar 84. As a result, the paper guide 83 is positioned at either the first guide position indicated by the solid line in the figure or the second guide position indicated by the alternate long and short dash line.

When the print job is started, the paper guide 8
3 is initially set to the first guide position shown by the solid line. Therefore, the paper with the front surface printed is guided by the paper guide 83 located at the first guide position and dropped onto the shooter 9 with the front surface facing upward. The shooter 9 is inclined and slides the received sheet downward. There is an intermediate tray 10 on the exit side of the shooter 9, and the paper slipping out from the shooter 9 is retained on the intermediate tray 13. Since the unprinted papers 2 are continuously sent out from the input tray 3, a plurality of papers 13 whose surface is completely printed are stacked on the intermediate tray 10. On the intermediate tray 10, the sheets 13 are stacked with the printed surface thereof facing upward in the figure (that is, face-up posture). Further, the sheets 13 on the intermediate tray 13 are reversed in the stacking order and the posture in the front-back direction as compared with the sheets 13 on the input tray 3.

After that, C in the image processing circuit described later is used.
Input tray 3 by the switching command sent from PU
The feeding of the sheet 2 from the tray is stopped, and the feeding of the sheet 13 from the intermediate tray 10 is started instead. That is, the rollers 14 send out the sheets 13 one by one in order from the uppermost one (that is, the one printed last) to the paper feeding device 5. The transport device 5 transports the sheet to the recording unit 1. The recording unit 1 transfers the image of the corresponding page onto the back surface of the sheet as a toner image, and the fixing unit 7 fixes the toner image on the back surface. This completes printing on both sides of the paper. When the switching command comes,
The driver circuit of the recording unit 1 switches the direction of reading the page image from the image buffer from the bottom to the top, which is opposite to that in the case of front-side printing (for the specific method of switching the reading direction, see, for example, Japanese Patent Publication No. 6-54222). Please refer to.). Therefore, in the back side printing, the bottom edge of the page image comes to the front edge side of the paper (that is, the back edge side in the front side printing), and as a result, the top and bottom of the back page image and the top and bottom of the front page image match. To do.

Further, in response to the switching command, the guide device 8 moves the paper guide 83 to the second guide position shown by the alternate long and short dash line. Therefore, when the paper on which both sides have been printed comes out of the fixing unit 7, the paper is guided by the paper guide 83 and is sent toward the paper discharge roller 15. The paper discharge roller 15 grips the paper and discharges it onto the output tray 16.
On the output tray 16, the sheets are stacked with the surface thereof facing downward (that is, face-down attitude). Moreover, on the output tray 16, the paper whose surface printing order is the last is placed at the lowest position. When all the printing of the paper 13 on the intermediate tray 10 is completed and all are discharged to the output tray 16, one print job is completed.

FIG. 2 shows a schematic configuration of an image processing circuit in the page printer.

The image processing circuit comprises a CPU 21 and a host interface circuit 2 interconnected by a bus 20.
2, a main memory device 23, an auxiliary memory device 24, and an engine interface circuit 25. The CPU 21 receives the print request data stream of the print job sent from the external host computer 100 through the host interface circuit 22, and based on this, generates a page image to be given to the print engine. The main storage device 22 includes a program ROM, a character generator, a main memory, a work memory, a reception buffer, the above-mentioned image buffer, and the like, which a conventional printer also has. Auxiliary storage device 24
Is not found in conventional printers, and the main memory 2
A storage having a capacity much larger than 3, for example, a hard disk device. The main use of the auxiliary storage device 24 is to store all of the print request data of one print job received from the host computer 100. The engine interface circuit 25 is a communication interface between the image processing apparatus and the print engine 26.

FIG. 3 shows the flow of print job reception processing performed by the CPU 21.

This process is started by recognizing the start of the print job sent from the host computer 100 (S1). The CPU 21 first stores the print request data of the received print job in the reception buffer in the main storage device 23, immediately transcribes the request data in the reception buffer into the auxiliary storage device 24, and leaves an empty area in the reception buffer. make. Subsequently, the subsequent print request data from the host computer 100 is received, stored in the empty area of the reception buffer, and immediately transferred to the auxiliary storage device 24. In this way, the CPU 21 receives and stores the print request data stream from the host computer 100 in the auxiliary storage device 24 as long as the stream of print request data continues (S).
2). After that, when the arrival of the print request data has stopped and a certain time has passed, or when the request data notifying the end of the job has arrived, the CPU 21 recognizes the end of the print job (S3), ends this processing, and continues. Then, the image generation process is started.

FIG. 4 shows the flow of image generation processing performed by the CPU 21.

First, pages to be printed on the front surface and the back surface of the paper are selected, and the printing order is determined (S1).
1). The most standard printing is to print an odd number of pages on the front side, an even number of pages on the back side, and finally sheets are stacked on the output tray 16 in order from the first page to the last page. It will be. Therefore, in the case of this standard printing, odd-numbered pages are selected on the front side, and the printing order is set in the reverse order of the page numbers. In addition, even-numbered pages are selected on the back surface, and the printing order is the same as the page numbers. For example, when printing a document of all 11 pages, odd-numbered pages are selected on the front side and the printing order is set to page 11, page 9 ,.
The order is page, page 1. In addition, even-numbered pages are selected on the back side, and the printing order is page 2, page 4, ..., Page 8, first.
The order is 0 pages.

Next, from all the data of the print job in the auxiliary storage device 24, the required data relating to the image of the page to be printed first on the front side of the paper is selected and read (S).
12). For example, in the above example, the request data related to the image on page 11 is read. Then, an image of the 11th page is created from the request data and stored in the image buffer in the main storage device 23 (S13). Then, the print engine 26 reads the image of the 11th page from the image buffer and prints it on the front surface of the sheet that is first taken in from the input tray 3. The first sheet is placed on the intermediate tray 10 in a face-up posture.

Thereafter, similar request data reading and page image creating operations are performed for the remaining remaining odd pages, that is, page 9,
..., repeated for page 3, page 1. As a result, the sheets on which the 11th page, the 9th page, ..., The 3rd page, and the 1st page are printed are stacked on the intermediate tray 10 in a face-up posture. Then, the sheet of the first page is placed at the uppermost position of the sheet stack 13.

When all the pages to be printed on the front surface have been printed (S14), the CPU 21 then sends the above-mentioned switching signal to the print engine 26 (S15). As a result, the print engine 26 switches to the system for performing back surface printing as described above.

Next, the CPU 21 selects and reads out the request data relating to the image of the page to be printed first on the back side, that is, the image of the second page from all the data of the print job in the auxiliary storage device 24 (( S16). Next, an image of the second page is created from the request data and stored in the image buffer (S17). Then, the print engine 26 makes the second
The image of the page is read from the image buffer, and is printed on the back side of the paper first taken in from the intermediate tray 10, that is, the paper on which the first page is printed. In this way, the paper on which the first and second pages are printed on the front and back is discharged onto the output tray 16 in a face-down posture.

Thereafter, similar request data reading and page image creating operations are performed for the remaining remaining even pages, that is, the fourth page,
..., repeated for page 8 and page 10. As a result, the sheets on which the first to second page groups to the ninth and 10th page groups are printed are stacked on the output tray 16 in a face-down posture. Moreover, the first to tenth pages are arranged in the order of page numbers.

When printing of all the pages to be printed on the back side is completed (S19), the CPU 21 next checks whether or not the total number of pages included in the print job is odd (S19). If it is an odd number, the last one sheet remains on the output tray 10, that is, the 11th page remains in the example used in the present description. Therefore,
The CPU 21 commands the print engine 26 to discharge the last sheet of paper onto the output tray 16 without printing (S2).
0). This completes the execution of one print job.

As can be seen from the above description, since the front side printing is performed all at once and the back side printing is performed at the same time, the reverse printing is performed between the front side printing and the back side printing of the individual sheets as in the conventional apparatus. No work is required, and printing of all pages can be continuously performed without a wasteful interval required for reversing work. The reason for the speed decrease is that all print request data of the print job is stored in the auxiliary storage device,
Although it is a labor to selectively read the print request data of a specific page from the auxiliary storage device, this can be solved relatively easily by increasing the speed of the processing circuit. As a result, higher throughput than before can be obtained. Further, since all the print job data is stored in the printer, there is an advantage that the host computer is released early.

Next, a page printer according to the second embodiment of the present invention will be described.

The print engine of this printer removes the intermediate tray 10, shooter 9 and guide device 8 from the configuration shown in FIG.
It is the same as the print engine of a one-sided printing printer. The block configuration of the image processing circuit is the same as that shown in FIG.

Referring to FIG. 1, in this printer, first, unprinted paper 2 on both the front and back is placed in an input tray 3,
Then, the sheets 2 are sent to the recording unit 1 one by one, and the image of the corresponding page is printed on the surface thereof. The sheet whose surface has been printed in this manner is discharged onto the output tray 16 in a face-up posture.

When all the pages to be printed on the front side have been printed, the printer enters a standby state. Meanwhile, the stack of sheets on the output tray 16 is transferred onto the input tray 3 by the user's hand. At this time, the paper stack is kept parallel to the front and rear postures and the vertical stacking postures, that is, the paper stacks are moved in parallel in the figure,
The output tray 16 is moved to the input tray 3. afterwards,
The user inputs a print restart command to the printer from the printer control panel or the host computer.

When this command is input, the CPU 21 issues the above-mentioned switching command, and the print engine starts printing on the back side. At the time of printing on the back side, in the above-described embodiment, the sheet on which the front side is printed is taken in from the intermediate tray 10, whereas in the present embodiment, it is taken in from the input tray 3, and the other is exactly the same. is there. When all the pages on the back side have been printed, the execution of the print job is completed.

FIG. 5 shows the flow of the image creating process performed by the CPU 21. The print job receiving process is the same as that shown in FIG.

As shown in FIG. 5, the CPU 2 first executes the process shown in FIG.
Similar to the case of the previous embodiment shown in (1), only the page image to be printed on the front surface is selectively created and stored in the image buffer (S31 to S34). Therefore, the front side is printed first, and the paper on the front side is printed on the output tray 1.
Stacked on 6. When the printing of all the pages on the front surface is completed, the CPU 21 temporarily stops the processing and informs the user of that fact by a warning sound or the like (S35), and thereafter, a print restart command is input from the control panel or the host computer. Wait for (S36). When a restart command is input,
The CPU 21 generates a switching signal (S37), and thereafter performs the same processing as that of the above-described embodiment (S38 to S4).
2).

According to this embodiment, since the print engine for single-sided printing can be used, it is much cheaper than all the embodiments. The disadvantage is that the user has to move the paper stack from the output tray to the input tray. However, since the transfer work is performed only once, it will not be a heavy burden on the user especially in a usage mode in which the user is near the printer, and the time loss due to it will be small.

The embodiments described above are merely examples and do not limit the present invention. The present invention can be implemented in other modes in which various variations, modifications and improvements are added.
For example, the face-up or face-down posture when the paper is output to the intermediate tray or the output tray may be one other than the examples in the above embodiment. In that case,
Depending on the posture, the determination of the printing order of pages also inevitably differs. Further, even-numbered pages may be printed first, and then odd-numbered pages may be printed. Also in the above-described embodiment, even-numbered pages are first printed in the order of page numbers (that is, S16 to
Then, the odd pages are printed in the reverse order of page numbers (then, S12 to S14 of FIG. 4 are performed). Finally, the pages are page-numbered in the face-up state. It is possible to obtain a print result in which In addition, the print images of all pages created by the CPU 21 are stored in the auxiliary storage device 24 in an appropriate data format (for example, final bitmap data, intermediate code in the preceding stage, or compressed data thereof). Alternatively, the image of a specific page may be selectively read from the image and sent to the print engine.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a print engine of a page printer capable of double-sided printing according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an image processing circuit in the page printer.

FIG. 3 is a flowchart showing processing when the CPU 21 receives a print job from the host computer 100.

FIG. 4 is a flowchart showing an image generation process performed by the CPU 21.

FIG. 5 is a flowchart showing a flow of image creation processing performed by the CPU 21 in the second embodiment.

[Explanation of symbols]

 1 Recording Part 2 Unprinted Paper 3 Input Tray 5 Paper Carrying Device 8 Guide Device 9 Shooter 10 Intermediate Tray 13 Surface Printed Paper 16 Output Stack 21 CPU 24 Auxiliary Storage Device

Claims (2)

[Claims] 1. A mass storage device for accumulating at least one of print request data and image information relating to all pages included in one print job, and a front page to be printed on the front side of a sheet of all the pages. And a back page to be printed on the back side of the sheet, and a printing order determining unit that determines a front page printing order that indicates the printing order of the front page and a back page printing order that indicates the printing order of the back page; Based on the information stored in the capacity storage device, first the image of the front page is output according to the printing order of the front page, and after the images of all front pages are output, the image of the back page is printed on the back page. Image output means for outputting in order, a printing mechanism for receiving the image of each page from the image output means and printing it on each sheet, and while the printing mechanism prints the image of the front page, A first paper feed mechanism that supplies unprinted paper to the printing mechanism, and stores all of the paper whose front surface has been printed by the printing mechanism, while the printing mechanism prints the image of the back page. A second paper feed mechanism that supplies the paper whose surface is printed to the printing mechanism. 2. The double-sided printing apparatus according to claim 1, wherein the first paper feed mechanism also serves as the second paper feed mechanism.