JPH04279373A - Perfect printing device - Google Patents

Abstract

PURPOSE:To print a printing sheet which follows even during a process in which the front and rear of the sheet are inverted in the perfect printing mode by setting a simulated page using a perfect printing data setting part and reading print data with a print timing set using a replacement control part. CONSTITUTION:After printing the front of a printing sheet, a setting device 13 sets the number of printable sheets as simulated pages while a printing medium 2 is inverted using a medium inverting part 9 and is again transported to a printing part 7. Before the simulated pages are deleted with specified print timing, a replacement control device 14 replaces said simulated pages with those to be deleted with the same print timing as set for print data for perfect printing of sheets that follow when entered. Further, the printing part 7 prints a printing medium 2 that follows fed from a medium feed part 1 using print data replaced. In addition, if all the simulated pages are deleted, print data at the rear of a perfect printing sheet is inverted using the medium inverting part 9 and is printed on the rear of the printing medium 2 transported from the third transport path 6 to the first transport path 4.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a printing device such as an electrophotographic printing device, and more particularly to a duplex printing device that is capable of printing on subsequent printing paper while reversing the printing paper from front to back during double-sided printing. It is related to.

[0002] In recent years, with the progress of office automation, there has been an increasing demand for character image information output devices that can use plain paper, have high printing speeds, have low noise, and produce beautiful prints. For this reason, printing devices, copying machines, and the like that utilize electrophotographic technology have been provided.

[0003] These devices have surface printing (
In the case of double-sided printing, the first one-sided printing is called front side printing)
However, it takes a long time to flip the printing paper and print on the back side, and the printing speed is significantly slower than when printing on one side. For example, a method of accumulating print data for a set of four sheets and repeating double-sided printing is used, but printing cannot start until the print data is accumulated, which hinders the speed up of printing. Therefore, a method to increase printing speed is desired.

0004

2. Description of the Related Art FIG. 8 shows an internal side view of an electrophotographic printing apparatus. In the figure, 1a is a paper feeding section that stores printing paper (hereinafter referred to as paper) 2a and is equipped with a feeding roller 3, 4a to 6a are conveyance paths, 7a is a printer section,
Reference numeral 8a indicates a stacker, and reference numeral 9a indicates a reversing unit for reversing the front and back sides of the paper 2a whose front surface has been printed.

[0005] The printer section 7a includes an optical unit 70,
Photosensitive drum 71, cleaner 72, charging section 73, developing section 74, transfer section 75, static eliminating section 76, and fixing section 77
It consists of The conveyance path 4a runs from the paper feed section 1a to the stacker 8 via the transfer section 75 and fixing section 77 of the printer section 7.
The conveyance path 5a is arranged after the fixing section 77, branching upward from the branch point a on the left side in the figure and reaching the reversing section 9a. 9a, bypassing the upper part of the printer section 7a, and transferring to the transfer section 75.
It is arranged so as to merge with the conveyance path 4a at the merging point b on the right side in the figure. A gate G1 for changing the conveying direction of the paper 2a is provided at the branch point a.

[0006] Also, the conveyance paths 5a, 6a before the reversing section 9a
A gate G2 is provided at a branch point c, and guides the paper 2a, which has been conveyed through the conveyance path 5a and arrived at the reversing section 9a, to the conveyance path 6a when it is moved in the opposite direction. This turns the paper 2a upside down.

[0007] Further, an operation panel (not shown) is provided with a double-sided printing designation button. With this configuration, when the power of the apparatus is turned on, the heat roller 78 of the fixing section 77 is heated to a predetermined temperature and becomes ready for printing, and the paper 2a is moved from the paper feed section 1a in the direction of arrow A based on the print instruction signal. It is unrolled, conveyed along the conveyance path 4a, and sent below the photosensitive drum 71. By this time, the photosensitive drum 71 has been neutralized by the static eliminating section 76, residual toner has been cleaned by the cleaner 72, and charged again by the charging section 73.

Therefore, optical data irradiated from an optical unit 70 composed of a laser light source or the like is transmitted to a photosensitive drum 71.
The electrostatic image formed on the photosensitive drum 71 is developed into a toner image in the developing section 74, and then transferred to the paper 2 in the transfer section 75.
After being transferred to the paper 2a, the paper 2a is held between the heat roller 58 and the pressure roller 59 in the fixing section 77, heated and pressurized, and fixed, and in the case of one-sided printing, the paper 2a is sent to the stacker 8a.

Furthermore, when the duplex printing designation button is pressed, or when a duplex printing designation signal is sent to the print data head sent from an external device (not shown), such as a host computer, the duplex printing mode is entered and the paper When the paper 2a is printed, the gate G1 is switched and the paper 2a is printed.
A is sent to the conveyance path 5a, is sent to the reversing section 9a, is sent in the opposite direction, the gate G2 is switched, and is then sent again to the printer section 7a via the conveyance path 6a, where it is printed on the back side of the paper 2a. and sent to the stacker 8a.

[0010] However, in general, the path for the paper 2a printed on the front side to return to the transfer unit 55 again via the transfer path 5a, reversing unit 9a, and conveyance path 6a from the transfer unit 55 is long and takes time. This is extremely long compared to the transfer time in the transfer section 55.

[0011] Therefore, if double-sided printing is performed one sheet at a time, high-speed printing cannot be expected.
For example, as shown in Figures 8(a) to (h), four sheets (
A method is used in which print data for 8 pages is stored as a set in a bitmap memory (not shown) and the printing sequence is repeated. In other words, 4 pages from 1 to
Expand to 8 pages and select 1, 3, 5 from this print data column.
, 7, 2, 4, 6, and 8 pages in order and print them in the following sequence. In (a) of FIG. 9, one page is printed, in (b), one page is sent to the conveyance path 5a, and three pages are printed, and in (c), one page is sent to the reversing section 9a, and three pages are sent to the conveyance path 5a. , print 5 pages,
In (d), one page is sent to the conveyance path 6a, and the third page is sent to the reversing section 9.
a, print page 5 to conveyance path 5a, print page 7, (
In e), the 3rd page is sent to the conveyance path 6a, and the 5th page is sent to the reversing section 9a.
7 pages are sent to the conveyance path 5a, 2 pages are printed, and (f
), the 2nd page is transferred to the stacker 8a, and the 5th page is transferred to the conveyance path 6a.
, print page 7 to inversion section 9a, print page 4, and (g
), the 4th page is transferred to the stacker 8a, and the 7th page is transferred to the conveyance path 6a.
, print 6 pages, and move 6 pages to stacker 8 at (h).
Print 8 pages to a and send them to the stacker 8a.

[0012] In this way, by the sequence (a) to (h), 1
, 3, 5, and 7, pages 2, 4, 6, and 8 are printed on the backs of four consecutive sheets from the first page that comes back.

[0013]

[Problems to be Solved by the Invention] According to the above conventional method, when printing on one side, the paper is sent directly to the stacker after being printed in the printer section, so high-speed printing corresponding to the printing speed of the printer section is possible. However, when printing on both sides,
A method is used in which print data for a plurality of sheets is printed in sequence as a set, by printing on one side of a sheet of paper, turning the front and back sides, and returning to the printing position again. However, since the print data for multiple sheets is expanded into the bit mat memory before printing, the input of this print data may be interrupted, the reception may be delayed, or there may be a delay in the expansion of image data, compressed data, etc. There is a problem in that it takes a long time to accumulate, and a printing waiting time occurs at the start of printing or at the end of a previous set of printing, and the printing speed decreases by that time, reducing the efficiency of high-speed printing.

[0014] The present invention allows easy control of double-sided printing;
Another object of the present invention is to provide a double-sided printing device that can efficiently perform high-speed printing.

[0015]

[Means for Solving the Problems] FIG. 1 is a diagram showing the basic configuration of the present invention. In the figure, 2 is a print medium, 1 is a medium supply unit that sequentially feeds out a plurality of print media 2 stored in a stack, 7
8 is a printing unit that prints print data transmitted from an external device onto the print medium 2; 8 is a stacker unit to which the printed print medium 2 is delivered; 4 is a stacker unit through which the unfed print medium 2 is sent via the printing unit 7; A first conveyance path 11 conveyed to the stacker section 8
9 is a medium reversing unit that inverts the printing medium 2 from front to back; 5 is a printing unit 7;
A print medium branched from the first conveyance path 4 at a later stage and printed on one side by the printing unit 7 when double-sided printing is instructed by an instruction signal added to print data input from the instruction means 11 or an external device. A second conveyance path 2 is conveyed to the medium reversing section 9, and a second conveyance path 6 is conveyed through which the printing medium 2 which has been reversed in the medium reversing section 9 joins the first conveyance path 4 before the printing section 7. The conveyance path 13 of No. 3 is a conveyance path 13 that is connected to the printing section 7 when double-sided printing is instructed, after the printing medium 2 is printed on the front side, until it is reversed from front to back in the medium reversing section 9 and conveyed to the printing section 7 again. A setting means 14 sets the number of pages that can be printed as a pseudo page at a predetermined printing timing after double-sided printing is instructed, and a setting means 14 erases the pseudo page set in the setting means 13 at a predetermined printing timing. However, when print data for subsequent front side printing is input before all the pseudo pages are erased, the replacement control means replaces the print data with the pseudo page to be erased at the appropriate timing.

Therefore, when the printing section 7 prints the print data replaced by the replacement control means 14 on the subsequent printing paper 2 fed out from the medium supply section 1 and all the pseudo pages are erased, the back side of the double-sided printing The printing unit 7 is configured to print print data on the back side of the print medium 2 conveyed from the third conveyance path 6 to the first conveyance path 4 .

[0017]

[Operation] When there is no double-sided printing instruction based on the instruction signal added to the print data inputted from the instruction means 11 or an external device, the recording medium 2 fed out from the medium supply section 1 is conveyed along the first conveyance path 4. The printed image is printed by the printing unit 7 and sent to the stacker unit 8.

When there is an instruction for double-sided printing, after the print medium 2 has been printed on the front side, the setting means 13 controls the print medium 2 until it is turned over in the medium reversing section 9 and conveyed to the printing section 7 again. In the meantime, the number of pages that can be printed is set as pseudo pages in the printing section 7, and the replacement control means 14 erases the pseudo pages set in the setting means 13 at a predetermined printing timing, before all the pseudo pages are erased. When print data for subsequent front side printing is input, the pseudo page that was supposed to be erased at the timing of printing that print data is replaced with the replaced print data and fed out from the media supply unit 1. The print unit 7 prints on the subsequent print medium 2. Also, when all the pseudo pages are erased, the print data on the back side of double-sided printing is reversed by the medium reversing unit 9 and the third
The printing unit 7 prints on the back side of the print medium 2 that is transported from the transport path 6 to the first transport 4.

In this manner, when performing double-sided printing, the printing medium 2 printed on the front side is passed through the second conveyance path 5, the medium reversing section 9, and the third conveyance path 6, and is then reversed. While returning to the printing unit 7, the subsequent print data is printed on the front side of the subsequent print medium 2 up to the number of pseudo pages, and then the front and back sides are reversed and side printing is performed on the returned print medium 2. This makes it possible to speed up double-sided printing with simple control.

[0020]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 2 to 4. The same reference numerals indicate the same objects throughout the figures. FIG. 2 shows a block diagram of an embodiment in which the present invention is applied to the electrophotographic printing apparatus described in the conventional example. The mechanism of the device is similar to that shown in FIG.

Paper feed section 1a, paper 2a, printer section 7a, and reversing section 9a in FIG. 8 and double-sided printing instruction button 11b in FIG.
, the double-sided data setting section 13a, and the replacement control section 14a are the medium supply section 1, print medium 2, printing section 7, medium reversing section 9, instruction means 11, setting means 13, and replacement control means 14 shown in FIG.
The transport paths 4a, 5a, 6a in FIG.
They correspond to the first conveyance path 4, the second conveyance path, and the third conveyance path 6 in FIG. 1, respectively.

In FIG. 2, the control section 10 is composed of a CPU and a control program, and the CPU controls each section based on the control program to perform single-sided printing and double-sided printing of print data sent from the host 19a.

The operation panel 18 has a double-sided printing instruction button 11a.
and operation buttons such as a power ON button for the device. When the device is in the normal state, that is, when the duplex printing instruction button 11a is not pressed, the device is set to the single-sided printing mode, and the duplex printing instruction button 1 is set to the single-sided printing mode.
When 1a is pressed, the duplex printing mode is set to print on both sides of paper 2a.

When double-sided printing is instructed, the double-sided data setting unit 13a sets the paper 2a to the conveying path 5 after the front surface of the paper 2a is printed.
The number of pages that can be transferred by the transfer unit 55 of the printer unit 7a is set as a pseudo page until the paper is reversed from front to back through the reversing unit 9a and the conveyance path 6a and conveyed to the printer unit 7a again. That is, for example, if 4 sheets are printed within the device,
When stored in the conveyance path 5a, reversing section 9a, and conveyance path 6a, the front and back sides of the first sheet are determined from the print data developed in the bitmap memory 12, as shown by the solid line in FIG. 3(a). The print timing of the print data is set, and between the front and back printing (pages 1 and 2) print data, as shown by the broken line, three (=4-1) front side printing pseudo pages g1, g2, Set g3 between the front and back data. After that, pseudo pages g4, g5, g6 will be created between the print data of the front and back prints of the second sheet (pages 3 and 4), and pseudo pages g7, g8, g8, g9 Set pseudo pages g10, g11, g12 between the print data of the 4th front and back printing (pages 7 and 8).

The replacement control section 14a includes the double-sided data setting section 1
After the print data set in 3a is output and printed on the front side of paper 2a, the pseudo pages set in the duplex data setting section 13a are erased at a predetermined printing timing, and before all the pseudo pages are erased. , When print data for subsequent front surface printing is input, the print data is replaced with a pseudo page to be deleted at the appropriate timing.

That is, for example, as shown in FIG. 3(a),
After the print data for the front side of the first sheet (page 1) is printed, when the print data for the front side of the second sheet (page 3) to be printed next comes at the specified printing timing, use the arrow to As shown, it is replaced with pseudo page g1. As shown in FIG. 3(b), if three pages of print data are not received, the pseudo page g1 is deleted. If print data continues to arrive, the pseudo page g will be printed at each printing timing.
2 and g3 are deleted, and when print data arrives, they are replaced with pseudo pages g2 and g3 at respective printing timings. Further, pseudo data g4 to g12 of the front and back print data for the second to fourth sheets are similarly erased or replaced depending on whether or not the print data arrives at the printing timing.

The bitmap data output unit 15 sequentially reads print data from the bitmap memory 12 when printing on one side, and outputs the print data from the double-sided data setting unit 1 when printing on both sides.
3a, a pseudo page is set, and the print data whose print timing is determined by the replacement control unit 14a is read out and sent to the printing unit 7a.

Since it has such a configuration and function, the operation will be explained next using the flowchart shown in FIG. 4, taking as an example the case where three pseudo pages are set between the above-mentioned front and back print data. ■First, in the normal one-sided printing mode, print data sent from the host 19a and input from the interface unit 16a is stored in the data memory 17, then developed in the bitmap memory 12, and then output. Printed on the paper 2a by the printer section 7a and transferred to the stacker 8
It is sent to a. Immediately after printing is finished, print the next sheet 2a.
is supplied and printing continues. ■When the duplex printing instruction button 11a on the operation panel 18 is pressed to set the duplex printing mode, or when there is a duplex printing instruction signal in the print data head sent from the host, the mode is switched to the duplex printing mode. , the print data inputted from the interface section 16a and stored in the data memory 17 is sent to the control section 1.
0 is developed in the bitmap memory 12, and the double-sided data setting section 13a sets print data for the front side (first page) and back side (second page) of the first sheet, and between the print data, 3 Pseudo pages g1, g2, and g3 are set. ■ The bitmap data output unit 15 immediately reads out the first page and starts printing, and then the replacement control unit 14a causes the pseudo pages g1, g2, g3
The front side (3rd page) and back side (
If the print data for the fourth page) is not developed in the bitmap memory 12, pseudo pages g1, g2, and g3 are sequentially erased. ■If the print data for the 3rd and 4th pages is input before the timing of printing pseudo pages g1, g2, and g3, the back side of 3 pages will be printed between the 3rd and 4th pages. Print pseudo pages g4, g5,
g6, and set the print data of the third page to pseudo pages g1, g2, g3 at the corresponding print timing.
The bitmap output unit 15 reads and prints the image by replacing it with one of the following. ■From now on, depending on the input timing of print data for the 5th and 6th pages, and the 7th and 8th pages, pseudo pages are deleted or replaced with print data and pseudo pages using the same procedure. Printed using the replaced print data. ■ After all of the pseudo pages g1, g2, and g3 have been erased or replaced with print data and printed, at the timing when the first sheet 2a is reversed and the second page returns to the transfer unit 55, Back side print data (2 pages) is printed. Thereafter, pages 4, 6, and 8 are printed in the same manner. (2) When the front and back printing of pages 1 to 8 for four sheets is completed, printing for the next four sheets is repeated according to the flow from (2) onward.

In this way, printing can be started immediately when the double-sided printing data for the first sheet is set in the double-sided data setting section 13a by simple control, so that printing data for a set of four sheets can be started as in the conventional example. Compared to the method of storing and then printing,
It can print much faster, and the printing speed per page can be as fast as simplex printing.

Further, a different embodiment (corresponding to claim 2) is shown in the block diagram of FIG. The structure of the device is similar to that shown in FIG. In FIG. 5, the same symbols as in FIG. 2 indicate the same objects. 5 is different from the embodiment of FIG. 2 in that FIG. 2 is a method for efficient and high-speed double-sided printing, whereas FIG. This is a method that can improve printing efficiency by interrupting single-sided printing of print data sent from the other host 19b during double-sided printing of print data sent from the host 19a (hereinafter referred to as mixed printing). .

[0031] Conventionally, in order to interrupt the printing of one side (double-sided printing or single-sided printing), there was a method of stopping printing and interrupting the printing, but printing efficiency was reduced because it could not be performed continuously. Therefore, a method to improve this problem has been desired, which can be solved by the present invention.

That is, in the block diagram of FIG. 5, the control section 10a has the same function as the control section 10 explained in the above embodiment, and furthermore, when mixed printing is instructed, it controls each section and prints the mixed printing. Perform printing.

The operation panel 18a has, in addition to the functions of the operation panel 18 described in the embodiment, a mixed printing instruction button 11b for instructing mixed printing. When the mixed printing instruction button 11b is pressed, a mixed printing mode is set in which single-sided printing is inserted into double-sided printing.

The single-sided data setting unit 13b sets print timing for the single-sided printing print data developed in the bitmap memory 12. When double-sided printing is performed using print data from one host, the replacement control unit 14b performs control in the same manner as the replacement control unit 14a described in the embodiment, and when mixed printing is instructed, print data for single-sided printing is performed. If the double-sided printing pseudo page corresponding to the printing timing is waiting to be deleted,
The print data for one-sided printing is replaced with the pseudo page, and if there is no pseudo page, the print data is inserted into the next print queue.

That is, for example, as shown in FIG. 6(a),
After the print data for front side printing (1 page) of the first sheet is printed, if the print data for single side printing to be printed next does not arrive, the pseudo data g1 is deleted as shown by hatching, and the data shown in Figure 6 ( b) When print data for single-sided printing is received, the print data is replaced with pseudo page g1, as shown in FIG. Thereafter, the pseudo pages g2 and g3 are replaced at the same printing timing of single-sided print data (the page order is indicated by 1' and 2'). Also, pseudo pages g1, g
After deleting 2 and g3, when the print data for single-sided printing is received, the back-side printing of the first sheet (
2 pages).

The bitmap data output section 15a functions in the same way as the bitmap data output section 15 described in the above embodiment when single-sided printing or double-sided printing is performed, and when mixed printing is performed, the bitmap data output section 15a functions as a replacement control section. 14b, the print data for single-sided printing is inserted into the print data for double-sided printing, and the print data whose printing timing is determined is read out, and the printing unit 7
Send to a.

Since it has such a configuration and function, the operation will be explained next with reference to the flowchart of FIG. ■When performing mixed printing by sending double-sided printing data from the host 19a and single-sided printing data from the host 19b in parallel, the mixed printing instruction button 11b on the operation panel 18a is pressed to set the mixed printing mode. Ru. First, double-sided printing data from the host 19a is input and stored in the corresponding storage area of the data memory 17a. ■Data memory 17a
The double-sided print data stored in is expanded into the bitmap memory 12 by the control unit 10a, and the double-sided data setting unit 13a sets the print data for the first and second pages of the first sheet, and In between, three pseudo pages g1, g2, and g3 are set. ■ Immediately the first page is printed, and then double-sided printing data is input, or single-sided printing data is input from the host 19b and stored in the respective corresponding storage areas of the data memory 17a, but the double-sided printing data When input is input, it is developed in the bitmap memory 12 in the same way as above, and when single-sided printing data is input, the single-sided printing data is developed in the bitmap memory 12 by the control section 10a, and the one-sided data setting section 1
The print timing is set in 3b. ■Pseudo page g1
, g2, and g3, if the third and fourth pages of single-sided print data or double-sided print data are not developed in the bitmap memory 12 by the timing of printing the pseudo pages g1, g2, and g3, the replacement control unit 14b Delete sequentially. (Figure 6(a) and (c)) ■Pseudo pages g1, g2,
If the single-sided print data or the 3rd and 4th pages of double-sided print data are input before each printing timing of g3, the single-sided print data or the 3rd page print data is input at the corresponding print timing. Pseudo pages g1, g2,
g3, bitmap output section 15
FIG. 6B shows a case where the single-sided print data is replaced with the pseudo page g1. If the print data of the 3rd page is replaced with any of the pseudo pages g1, g2, g3, then between the print data of the 3rd and 4th page, 3 pseudo pages g4, g5, Set g6. ■
Furthermore, when the one-sided print data arrives after all of the pseudo pages g1, g2, and g3 have been erased, it is inserted next to the second page of the double-sided print data, as shown in FIG. 6(c). Then, printing is performed using the one-sided print data. ■Below,
Depending on the input timing of the print data for the 5th and 6th pages, 7th and 8th pages of single-sided print data and double-sided print data, the pseudo pages can be deleted using the same procedure, or the single-sided print data or double-sided print data can be printed. Any of the data is replaced with the pseudo page, and the replaced print data is printed. The process of determining the order of pages of print data that are sent sequentially in this manner is illustrated in FIG. 6(d).

[0038] In this way, mixed printing of double-sided printing and single-sided printing can be performed continuously, and efficiency can be significantly improved. In addition, if mixed printing is performed and if they are sent together to the stacker 8a and cannot be distinguished, the transport path 4a may be branched near the end, a stacker may be installed for each, and a gate may be installed at the branching point. It is also possible to provide a method in which the gates are switched and controlled depending on whether double-sided printing or single-sided printing is performed, and the sheets are sent to separate stackers.

In the above embodiment, the case of an electrophotographic printing apparatus has been described, but the present invention can be similarly applied to a case where a copying machine automatically feeds out a single-sided original to read it and print on both sides. be able to. Further, in the case of double-sided printing of a double-sided original, the present invention can be similarly applied by providing a reversing mechanism corresponding to the paper and the original and adjusting the timing of conveyance and reversal.

In the different embodiments described above, a case has been described where double-sided printing data is sent from the host 19a and single-sided printing data is sent from the host 19b, and mixed printing is performed.
It can also be applied to mixed printing when double-sided printing data is transmitted from both a and 19b.

[0041]

[Effects of the Invention] As explained above, according to the present invention, 1
) In claim 1, when double-sided printing is performed on a print medium, while the print medium printed on the front side by the printing unit returns to the printing unit through a path that reverses the front and back sides, subsequent print data is transferred to the subsequent print medium. Since it is possible to print on the front side up to the number of pseudo pages and then print on the back side of the returned print medium, it is possible to speed up double-sided printing with simple control. 2) In claim 2, when double-sided printing print data and single-sided printing print data are sent from different external devices, the single-sided printing print data can be printed by interrupting the double-sided printing pseudo page. Therefore, double-sided printing and single-sided printing can be performed continuously, and printing efficiency can be improved. There is an effect.

[Brief explanation of the drawing]

[Figure 1] Principle configuration diagram of the present invention

[Figure 2] Block diagram showing an embodiment of the present invention

[Figure 3]
Explanatory diagram of the example

[Figure 4] Flowchart of the example

[Figure 5] Block diagram showing different embodiments

[Figure 6]
Explanatory diagram of different embodiments

[Figure 7] Flowchart of different embodiments

[Figure 8]
Internal side view of electrophotographic printing device

[Fig. 9] Explanatory diagram showing a conventional printing sequence

[Explanation of symbols] 1 is a medium supply unit, 2 is a print medium,
2a is paper, 4, 5, 6, 4a,
5a, 6a are conveyance paths, 7 is a printing section,
7a is the printer section, 8, 8a is the stacker,
9 is a medium reversing unit, 9a
1 is a reversing unit, 11 is an instruction means, 1
1a is a double-sided printing instruction button, 11b is a mixed printing instruction button,
13 is a setting section, 13a is a double-sided data setting section, 1
3b is a one-sided data setting section, 14 is a replacement control means, 14a
, 14b is a replacement control unit,

Claims (2)

[Claims] Claim 1: A plurality of print media (2
), a printing section (7) that prints print data transmitted from an external device onto the printing medium (2), and a printing section (7) from which the printed printing medium (2) is sent out. The stacker section (8) and the unfed print medium (2)
) passes through the printing unit (7) to the stacker unit (8).
a first conveyance path (4) conveyed to the print medium (2);
), a medium reversing section (9) for reversing the printing medium (2) from the first conveyance path (4) at a stage subsequent to the printing section (7); When double-sided printing is instructed by an instruction signal added to print data input from the instruction means (11) or an external device, the printing medium (2) printed on the front side by the printing unit (7) The second conveyance path (5) is conveyed to the medium reversing section (9), and the printing medium (2) whose front and back sides have been reversed in the medium reversing section (9) is conveyed, and the printing medium (2) is conveyed to the printing section (7).
), and a third conveyance path (6) that merges with the first conveyance path (4) at the front stage of The printing medium (2)
A double-sided printing device in which the printing unit (7) prints on the back side of the printing medium (7), when the double-sided printing is instructed, the printing medium (
2) After the front side of the media is printed, the number of sheets that can be printed in the printing unit (7) is simulated until the medium is reversed in the media reversing unit (9) and conveyed to the printing unit (7) again. A setting means (13) for setting as a page, and a setting means (13) for setting a page after the printing medium (2) is printed on the front side.
If the pseudo page set to is deleted at a predetermined printing timing, and print data for subsequent front side printing is input before all the pseudo pages are deleted, the print data is deleted at the corresponding timing. A replacement control means (14) for replacing the pseudo page to be erased is provided, and the print data replaced by the replacement control means (14) is transferred to the subsequent printing paper (2) fed out from the medium supply section (1).
) is printed by the printing unit (7), and when all the pseudo pages are erased or replaced, the print data on the back side of double-sided printing is transferred from the third conveyance path (6) to the first conveyance path (4). ) A double-sided printing device characterized in that the printing unit (7) prints on the back side of the print medium (2) conveyed to the printing medium (2). 2. When single-sided printing is performed by interrupting print data input from a second external device during double-sided printing using print data input from a first external device, the replacement control means (14) If the pseudo page of double-sided printing is waiting to be erased, the print data of the single-sided printing is replaced with the pseudo page that should be erased at the corresponding timing, and if there is no pseudo page, the process is interrupted to wait for the next printing. 2. The double-sided printing apparatus according to claim 1, wherein