JPH022581A - Both-sides printer - Google Patents

Abstract

PURPOSE:To perform both-sides printing efficiently by providing an odd-page buffer storage device and an even-page buffer storage, and reading out necessary data at necessary time and controlling the printing. CONSTITUTION:Cutforms whose top surfaces are already printed are sent into a form inversion passage 30 and plural cutforms are stored, and they are supplied to a transfer stage below a photosensitive drum 14 again for reverse- surface printing, data on odd pages and data on even pages are stored in different buffer storage devices 68 and 60, and a read of those data is controlled. Consequently, the data can be printed on the top and reverse surfaces of the cutforms alternately and continuously and the printing speed of the both-sides printing is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a 7-h photo type double-sided printing device capable of printing on both sides of a cut sheet.

[Prior Art] Conventionally, in this type of duplex printing device, after printing on one side of a sheet of paper, the operator turns the paper over and sets it in the paper feed slot again to print on the other side. Ta. Then, after this double-sided printed sheet is discharged from the printing device, the next sheet is similarly double-sided printed.

In some cases, instead of an operator, a paper reversing machine +M built into the printing apparatus is used to reverse the paper.

[Problems to be Solved by the Invention] The conventional double-sided printing apparatus described above cannot print the next sheet of paper until both sides of one sheet of paper have been printed, so the printing speed of double-sided printing is slower than that of single-sided printing. It has the disadvantages of being old.

In consideration of the above points, an object of the present invention is to efficiently perform double-sided printing.
An object of the present invention is to provide a double-sided printing device that can be implemented.

[Means for Solving the Problems 1] In order to achieve the above object, the double-sided printing device according to the present invention includes a paper feeding means for supplying the cut sheet to the transfer stage, and a feeding means for the cut sheet discharged from the fixing stage. a paper guide that selectively switches the direction between a paper ejection port and a paper reversing path; and a paper guide capable of storing a plurality of sheets of cut paper that has entered the paper reversing path, so that the side opposite to the printed side can be stored. a paper reversing mechanism that inverts the cut sheet so that it faces the photoreceptor and supplies it again to the transfer stage; an odd page buffer storage device that stores the contents of the odd numbered pages to be printed for the number of pages to be printed; The apparatus includes an even page buffer storage device for storing contents of a plurality of even pages, and a print control means for controlling input/output of the two buffer 1 storage units.

[Effect 1 The double-sided printing device of the present invention operates as follows.

Initially, only the front surfaces of several sheets of paper are printed and stored in the path of the paper reversing mechanism. Next, the first sheet of paper whose front side has been printed is reversed and sent to the transfer stage again, and printing is performed on the back side of this first sheet of paper. In this way, the cut sheet on which double-sided printing has been completed is discharged from the paper discharge port. After that, a new Ig from the paper cassette
The paper and the cut paper whose front side has been printed from the paper reversing mechanism are alternately supplied to the transfer stage. Then, the paper with the front side (center side) is sent into the paper reversing path, and the double-sided cut paper is ejected from the paper ejection port.In order to use this printing method, odd page buffer storage is A printer and an even page buffer storage device are provided, and necessary data is read out from these buffer storage devices at a necessary time and printed.

[Example] Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of an embodiment of the double-sided printing apparatus of the present invention.

This printing device, like a normal electrophotographic printing device,
Paper force rollers 1 to 10, paper feed roller 12, photosensitive drum 14
, U0 feed belt 16, fixing roller 18, discharge roller 20
are arranged 4 in order along the feeding direction of the cut sheet. A main charger 22 is provided below the photosensitive drum 14.

A first paper guide 24 is arranged between the fixing roller 18 and the discharge roller 20 to change the feeding direction of the cut paper. As shown in an enlarged view in FIG. 2, the first paper guide 24 can rotate around a shaft 25 and can be selectively switched between the position shown by the solid line and the position shown by the two-dot chain line. .

Returning to FIG. 1, above the first paper guide 24, two conveyor belts 26, 28 extend in the vertical direction, and a paper reversing path 30 is formed between them. The conveyor belt 26.28 has a first pulley 32.34 and a 21st pulley 32.34.
It is hung between 36 and 38. Second pulley 36
, 38 and the 31st relay 40.42 is another horizontally extending conveyor belt 44.46 tl! ) is being kicked. A reversing roller 48 is arranged near the third pulleys 40, 42, and a second paper guide 50 is arranged between the third pulleys 40, 42 and the reversing roller 48. As shown in an enlarged view in FIG. 3, the second paper guide 50 can rotate around a shaft 51 and can be selectively switched between the position shown by the solid line and the position shown by the two-dot chain line. .

A print control device 52 that controls double-sided printing is provided inside the printing device. A block diagram of this print control device 52 is shown in FIG. 4. A print control circuit 54 included in the print control device 52 can receive and receive data from a host device 62 and output data to a print device 64. can do. Here, the printing device 64 includes normal printing components and movable mechanisms unique to the present invention, such as a first paper guide and a paper reversing mechanism.

The print control circuit 54 is connected to a page control circuit 56, and the page control circuit 56 is connected to the odd page buffer 1 storage device 5B.
and an even page buffer storage device 60. Each of these buffer storage devices has a storage capacity sufficient to store several pages of data.

Next, the operation of this embodiment will be explained. In Figure 4,
First, from the host 1 to the device 62 to the print control circuit 54,
Print data is sent. This data is analyzed and sent to the page control circuit 56. Page control circuit 56
Now, data for odd pages is stored in odd page buffer/storage device 58, and data for even pages is stored in even page buffer storage device 60. Assuming that each buffer storage device has a storage capacity of five pages, the odd page buffer storage device 58 initially stores pages 1, 3, 5, 7, and 9. The print data for the eyes is stored. On the other hand, even page buff?
The storage device 60 stores print data for the second, fourth, sixth, eighth, and tenth pages.

First, the page control circuit 56 controls the odd page buffer 7.
Data at the start address of the bottom line of the storage device 58 (1
The print data is sent to the print control circuit 54 in order from the first data of page number.

Based on this data, the photosensitive drum 14 is exposed by the exposure device (not shown) of the printing device 64. In the odd page buffer storage device 58, after the data of the first page is read out, the data of the third and subsequent pages are sequentially sent to the first address, and the data of the eleventh page is newly sent from the page control circuit 56 to the empty space. It is sent and stored.

FIG. 5 is a time chart of this embodiment.
In the even-numbered buffer storage device, the access state by the page control circuit is kept low at L level.

Returning to FIG. 1, the cut sheet is sent from the paper cullet 10 by the paper feed roller 12 to the transfer stage below the photosensitive drum 14, and the first page data is printed on the surface of the cut sheet. In this specification, the "front side" of the cut sheet refers to the upper side of the cut sheet placed in the paper cassette 10, and the "back side" refers to the opposite side. shall be taken as a thing.

The cut sheet on which the contents of the first page have been transferred is sent to a fixing stage by a conveyor belt 16, and the transferred data is fixed by a fixing roller 18.

At this time, the first paper guide 24 is in the state shown by the two-dot chain line in FIG.
guided by.

Next, the photosensitive drum 14 is exposed to light for the third page, and the data for the third page is transferred and fixed onto the surface of the second cut sheet. The second sheet of paper is also guided to the paper reversing path 30. Single sheet in the paper reversing path (conveyor belt 2)
6.28.44° 46 toward the second paper guide 50. In this way, only the odd numbered pages are printed on a predetermined plurality of sheets of paper, and the paper reversing path 3
Store this in 0. Here, in order to simplify the explanation, it is assumed that the number of cut sheets stored in the sheet reversing path 30 is two sheets.

Since two sheets of paper have accumulated in the paper reversing path 30,
The first sheet of paper is turned over and sent to the transfer stage again. That is, the first sheet of cut paper 11 passes through the second paper guide 50 shown by the solid line in FIG. is sent out to the top of the paper tray 49. Then, the reversing roller 48 stops with only the trailing edge of the paper being held between the reversing rollers 48. Next, the second paper guide 50 rotates to the state shown by the two-dot chain line, and the reversing roller 48 begins to reverse. Then, the cut sheet 11 is sent downward along the lower surface of the second sheet guide 50, and is then fixed and lowered by the guide 47 shown in FIG. 1. Furthermore, this cut sheet is sent to the transfer stage by a reversing paper feed roller 45.

On the other hand, the photosensitive drum 14 has an even page buffer? The data of the second page read from the storage device 60 is exposed,
This data is transferred and fixed on the back side of the first cut sheet. Note that in the even page buffer storage device 60 as well, similarly to the odd page buffer storage device 58, after data is read, the data contents are sequentially forwarded.

By the above procedure, the second page will be printed on the actual measurement of the first page. At the same time, the first paper guide 24
The state shown by the solid line in the figure (hereinafter referred to as the passing state) is reached.

Therefore, the first cut sheet 11 is fixed at -518
After being ejected, the paper passes over the first assembly guide 24 and is ejected from the ejection port 21 by the ejection roller 20.

Next, the fifth page is printed on the front side of the third sheet, and then the fourth page is printed on the back side of the second sheet. In this way, as shown in the time chart in Figure 5, only the front side printing is performed for the first few sheets (two sheets in this example), and then front side printing and back side printing are performed alternately. be done. That is, for the first few sheets, data is read out continuously from the odd page buffer storage device, and thereafter data is read out alternately from the even page buffer storage device and the odd page buffer storage device, and at the same time, data is read out from the even page buffer storage device and the odd page buffer storage device. The paper kite is also alternately switched between an inverted state and a passing state.

After printing on the back side, front side printing is always performed on a new cut sheet, so the number of sheets stored in the paper reversing Bl 4M decreases due to front side printing, and the sheet for front side printing is immediately printed. Paper will be replenished.

In the manner described above, double-sided printing is carried out extremely efficiently.

The correspondence relationship between the configuration of the present invention and the configuration of this embodiment is as follows.

Paper feeding means: paper force rollers 1 to 10 and paper feeding rollers 12 (guide: first assembly kite 24) Paper reversing mechanism: conveyor belts 26, 28.4='1..46 and Second
Paper guide 50, reversing roller 48, guide 47, and reversing paper feed roller 45 Odd page pack 1 storage device...Odd page buffer storage device 5B Even page buffer? Storage device...even page buffer? Storage device 60 Print control means: print control circuit 54 and page control circuit 56 In the above embodiment, the number of cut sheets stored in the paper reversing path was set to two, but of course, the number can be changed to any desired number. It can be multiple sheets.

Further, in the above embodiment, it is assumed that the storage capacity of the buffer storage device is one for five pages, but the present invention is not limited to this.

[Effects of the Invention 1] As explained above, the double-sided printing device of the present invention sends the cut sheet with the front side stamped into the paper reversing path, prints the back side of the sheet, and prints the back side. In addition to supplying this data to the transfer stage again for the transfer stage, the odd page data and the even page data are stored in separate buffers and storage devices to prevent reading of these pages.
This makes it possible to alternately and continuously print on the front and back sides of the cut sheet, which has the effect of improving the printing speed of double-sided printing.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of one embodiment of the present invention, and FIG.
FIG. 3 is an enlarged explanatory view of the paper guide, FIG. 3 is an enlarged explanatory view of the second paper kite, FIG. 4 is a block diagram of the print control device of this embodiment, and FIG. 5 is an illustration of the timer 1 of this embodiment. 10...Paper cassette 12...Paper feed roller 14...Photosensitive drum 18...Fixing roller 24...First paper kite 26.28.44.46...Transport belt 30...Paper Reversing path 45...Reversing paper feed roller 48...Reversing roller 50...Second paper guide 4...Print control circuit 6...Page 1111I13 (1 circuit 8...Odd page buffer storage device O ...even page buffer storage device

Claims (1)

[Scope of Claim] An electrophotographic double-sided printing device capable of printing on both sides of a cut sheet, comprising a paper feeding means for supplying the cut sheet to a transfer stage and a feeding direction of the cut sheet discharged from the fixing stage. , a paper guide that selectively switches between a paper ejection port and a paper reversing path; and a paper guide that can store a plurality of sheets of paper that has entered the paper reversing path, and exposes the side opposite to the printed side. a paper reversing mechanism that inverts the cut sheet so that it faces the body and supplies it again to the transfer stage; an odd page buffer storage device that stores the contents of the odd numbered pages to be printed for a plurality of pages; and an odd numbered page buffer storage device that stores the contents of the odd numbered pages to be printed. A double-sided printing device comprising: an even page buffer storage device for storing contents of a plurality of pages; and print control means for controlling input/output of the two buffer storage devices.