JPS59179354A - Recording apparatus - Google Patents

Abstract

PURPOSE:To obtain an efficient and general-purpose recording apparatus, by forming the same so as to be capable of performing double-surface printing according to necessity by altering a printing control means. CONSTITUTION:The titled apparatus is formed so that a sheet (of which the first surface corresponding to an even number page is printed) directly after fed from a paper feed part 1-1 and a sheet (of which the second surface corresponding to an odd number page is printed) having gone around a conveying loop containing a reversal mechanism 1-10 alternately pass a drum 1-3. On the other hand, when an odd number M-surface comes after the first surface of a certain sheet arrives the position of the drum 1-3, the second surface of said sheet is allowed to again return to the position of the drum 1-3. In order to realize the order of accurate and continuous page printing, memories are alternately fabricated on ring shaped page buffer 3-4 in such a form that an even number page group advances in the phase thereof over M-pages from an odd number page group. When the page buffer number of the page buffer 3-4 is brought to an even number 2M, because M is an odd number, the even number page and the odd number page can be alternately printed and double-surface printing is accurately performed.

Description

[Detailed Description of the Invention] Technical Field The present invention provides a method for recording on the back side of a sheet if necessary.
The present invention relates to a recording device configured to do so.

BACKGROUND ART Conventionally, in recording apparatuses that record only on one side of a sheet, the other side remains completely unused. Therefore,
Compared to the case where records are made on both sides, the amount of sheets required is doubled, which is a factor that greatly increases the cost required for recording. Furthermore, the storage location for recorded sheets, the amount of sheets to be prepared before recording, etc. all doubled, and the difference between tangible and intangible negative phases was large.

Purpose In view of the above-mentioned points, it is an object of the present invention to provide a recording device configured to be able to record on both sides of a sheet as necessary.

In order to achieve such an object, the present invention includes a buffer memory for registering recorded information, a first means for storing recorded information into the buffer memory in a predetermined order pattern, and a method for writing information from the buffer memory in parallel with writing. and a second means for reading out the recorded information in a different predetermined order pattern, and there is no double-sided printing? f) Accordingly, 4.1' is formed.

Example Hereinafter, the present invention will be described in detail with reference to ), ;i-planes.

FIG. 1 shows a sheet conveying system of a duplex printing system fj which is an embodiment of the present invention. In this figure, 11 is a paper feed section, 1-
2 is a transfer path with 11 transfer paths, and 1-3 is a well-known 11Σzi'r.
F sheets using true technology! Drum l\, 1-4 rolls toner 1°ψ from drum l-3'' onto the sheet of paper, forming a toner image on the surface of L paper. γ transfer charger, 1-
5 is a pre-fixing conveyance path; 1-6 is a fixing device that fixes the i.ner image transferred to a sheet of "paper" by heat and pressure; 1;
-7 is a W feed path after fixing, 1-8 is a branching mechanism for branching the sheet conveyance IY path, 1-8 is a conveyance path before reversal, and 1-10 is for reversing the front side of the sheet. A reversing mechanism using a known three-way roller, 1-11 is a reversing back feed path, 1-12 is a pre-stacker conveyance path, and 1-13 is a stacker.

During double-sided printing, sheets fed from the paper feed section 1-1 are conveyed to the drum 1-3 via the rotation 77 and the front conveyance path 1-2. Then, the l.color image 1o formed on the drum 1-3 using the well-known Shigeko photography technique is transferred onto a sheet of paper by corona discharge in the transfer charger 1-4, and is then transferred to a conveyance path before fixing. 1-5 to the fixing device +-e. The paper that has undergone the first image fixation in the fixing device 1-8 is conveyed via the pre-fixing conveyance path 1-7, passes through the branching mechanism 1-8 and the pre-reversing conveyance path 1-8, and then is transferred to the reversing mechanism l-8. Sent to 10.

The single-sided printed sheet whose front and back sides have been reversed in the reversing mechanism 1-10 is sent to the reversing J' front transport path 1-2 via the 5-reversing back transport path 1-11, where it is transferred to the drum 1-3 and the transfer path 1-2. Image transfer on the back side (second side) is performed by the charger 1-4 in the same way as in the previous one-sided printing. Thereafter, it is sent to a fixing device 1-8 via a pre-fixing conveyance path 1-5, where the image on the second side is fixed. At this point, double-sided printing is complete.

The double-sided printed sheets are stacked on the stacker 1-13 from the pre-fixing transport path 1-7 through the branching mechanism 1-8 and the pre-stacker transport path 1-12.

The process of double-sided printing on a single sheet of paper is as shown below, but in reality, it is not possible to wait for the completion of double-sided printing on one sheet before starting printing on the next sheet. Due to the fact that the transport path is considerably long compared to the length of the sheet, a reduction in the throughput I.

Therefore, in order to obtain the same throughput as when printing on one side (i.e., the number of pages printed within a medium time),
It is necessary to pass the sheets through the drums 1-3 at the same intervals as when printing on one side. As a method for realizing such a function, in the present embodiment shown in FIG. 1, the time interval between feeding sheets from the paper feeding section 1-1 is doubled as the interval during one-sided printing. Furthermore, in this embodiment, after finishing printing on one side, the reversing mechanism 1-1
When the sheet reversed by 0 flows into the pre-transfer conveyance path 1-2 from the reverse back conveyance path 1-11, the unprinted sheet immediately after being sent from the paper feed section 1-1 and the unprinted sheet are separated. Configure it to be exactly in the middle.

By operating in this way, the pre-transfer conveyance path 1-2
From drum 1-3. Transfer charger 1-4. Pre-fixing transport path l
-5. Fixing device 1-6. Fixed pattern feeding path 1-72 branching mechanism 1
In the conveyance path up to -8, sheets whose back side has already been printed and sheets whose first side has been printed only flow alternately.

A branching mechanism 1-8 branches alternately arriving double-sided printed sheets and single-sided printed sheets to a pre-stacker transport path 1-12 or a pre-reversal transport path 1-9, respectively. .

In this case, the pre-transfer conveyance path 1-2. Drum l-3, pre-fixing conveyance path l-5. Fixing device 1-6. Fixing support transport path 1-79 Branching mechanism 1-89 Pre-reversal transport path 1-99 Reversing mechanism 1-10
．． The length of one conveyance loop consisting of the post-reversal feed path 1-11 must be an odd multiple of the sum of the length of the sheet in the conveyance direction and the interval between the sheets. If it is an even number, the sheet fed from the paper feed section 1-1 and the sheet from the reversing back feed path 1-11 overlap on the pre-transfer conveyance path 1-2. This causes the inconvenience of being lost.

In other words, after the first side of a certain sheet arrives at the position of drum 1-3, the second side of that sheet returns to the position of drum 1-3 again on the odd-numbered side. It is.

In this embodiment described above, the spacing between both sides of the sheet (i.e.,
The first printing completed! : The paper is +liυ on drum 1-3 with A' and 3. The second ini printing is done on drum 1-3) 1 (after 1 passing I7, what number sheet corresponds to it? Let t) be M. Therefore, for example, when M=5, after the printing of the first side is completed, the second
Four new sheets will be printed before the first side is printed.

In addition, when printing on only one side, it is necessary to place the sheet in the stacker 1-13 with the printed side facing down in order to maintain the page rotation of the sheet correctly.

On the other hand, when printing on both sides, it is necessary to stack the paper with the second printed side facing down. That is, in order to properly arrange the image rotation during double-sided printing, it is necessary to print the later pages of the R-page printed on both sides of a certain sheet for the first time. If it is assumed that printing starts from the first page, the even numbered pages will be printed before the odd numbered pages.

Figure 2 shows the transport system shown in Figure 1 and the state of sheets flowing through it! FIG. 2 is a schematic diagram showing a spoon in a case where the spacing between both sides is 5. In this figure, 1 reversing mechanism 1-10 is schematically represented as a section in which a sheet is reversed while passing through this section. Further, 2-1 is a conveyance loop for sheets, and sheets 2-2-1 to 2-2-51 are being conveyed. Here, the number j in parentheses written on both sides of each sheet is the page number printed or currently being printed on that side, and the number in parentheses indicates the page number to be printed.

In FIG. 2, unhatched sheets 2-2-2 and 2-2-4 have not yet been reversed, and hatched sheets 2-2-1 and 2-2-3 indicates that it has been reversed. Furthermore, the sheet 2-2-5 that is partially hatched indicates that it is currently being reversed by the reversing mechanism 1-10.

FIG. 3 shows a schematic diagram of an offline printing system to which the present invention is applied. In this figure, 3-1 is a magnetic tape (hereinafter abbreviated as MT) on which printing information, control information, etc. have been recorded.
-2 is a magnetic information converter that converts the information in MT3-1 into electrical signals, 3-3 is a central processing unit (hereinafter abbreviated as CPU) that controls the entire system, and 3-4 is each terminal 3-5 is printing hardware that transfers the print information in the page buffer 3-4 under the control of the CPU 3-3; 3-6 is the actual printing Printing device M, 3-7
1 pointer indicating the page/page information to be created 3-4, 3-8 is the page buffer 3-4
, a page number rank indicating the number of page information created in , and a print point indicating the page currently being printed.

Based on the information X read from the MT 3-1, page information created on the page buffer 3-4 is created successively, such as the first page, second page, and third page. However, in a system as in this embodiment, in which the sheets on which the first side is printed and the sheets on which the second side is printed alternately, the order of the pages to be printed is not consecutive. . Therefore, means for absorbing and adjusting this difference is required. FIG. 4 is a conceptual diagram showing page order control for double-sided printing in this embodiment. This figure shows an example where the distance between both sides is M=3, and shows the state in which up to the fourth page has been created. Here, the six-tree arrow group 4-1 written in the six (=2M) ring-shaped page buffers 3-4 represents the order in which page information should be created. Further, the numbers written in the ring of the purge buffer 3-4 indicate the page numbers. The arrow 4-2 represents the page creation start position (ie, the initial value of the set pointer 3-7) indicating the page buffer in which the page buffer should be created first.

Page numbers 5 and 6 are enclosed in parentheses because the page number 5 is in this page buffer, although it has not yet been created.
This indicates that the page or the sixth page is scheduled to be created. Printing is started when four pages (generally one page) of page information have been created.

Further, a thick arrow 4-3 represents a print pointer 3-9. That is, the page information of the page buffer γ pointed to by the thick arrow 4-3 will be printed. The initial position of the thick arrow 4-3 (i.e. the initial position of the print pointer 3-9 (+i
'i) must be at a position M pages away from the page creation start position 4-2 on the ring-shaped image huffer 3-4. This thick arrow 4-3 is arrow 4
-4 direction (ie, clockwise).

The page printing order is 2 pages, with a blank page.

Page 4, page 1 (back of page 2), etc. In a double-sided printing system in which the first side [1 and the second side are printed at an intersection of 771], a predetermined page printing order is determined in this way. Here, printing a blank page means printing a blank page on the entire surface or not printing for a time corresponding to printing one page.

In this embodiment, the sheet immediately after being fed from the paper feed unit 1-1 (the first side and even numbered pages are printed) and the sheet that has gone through the conveyance loop including the reversing mechanism (the first Since the sheets (for printing two-sided, odd-numbered pages) alternately pass through the drum 1-3, the paper feed section 1-1 is configured in advance to feed every other sheet.

For a while after starting printing, there are no sheets in the transport loop 2, and only the sheets immediately after being fed pass through the drums 1-3 every other sheet. Therefore,
For a while after starting printing, printing of even-numbered pages and printing of blank pages must be performed alternately. Furthermore, at the final stage of printing, it is necessary to print odd-numbered pages on the sheets that have passed through the transport loop after paper feeding is completed. Therefore, in this case, blank pages and odd-numbered pages are printed alternately.

FIG. 5 is a conceptual diagram showing page order control when the double-sided spacing M is set to 5. In this figure, arrow groups 5 to 11 indicate the order in which pages are created, where solid lines indicate transitions from odd pages to even pages, and broken lines indicate transitions from even pages to odd pages. Also, arrow 5-2 indicates the page creation start position,
The large arrow 5-3 represents the printing pointer 3-9, and the arrow 5-4 represents the advancing direction of the large arrow 5-3.

2M, or 10, ring-shaped page buffers 3-
The number written within 4 is the page number. Also, the page number? , 8, 9, and 10 are enclosed in parentheses (11) to indicate that these pages have not yet been created. Therefore, the page printing order in this case is page 2, blank page, 4A'-page, blank page.

Page 6, 1st page (back of page 2).

This is the page printing order in double-sided printing.

As is clear from a comparison between FIG. 2 and FIG. 285, the ring-shaped page buffer 3-4 imitates a sheet-shaped page in the transport loop 2-IJ. That is, in the arrow group 5-1, both pages connected by solid arrows correspond to both sides of one sheet.

The following explanation is based on the case where the distance M between both surfaces is 3 or 5 using FIGS. 4 and 5.

Next, a description will be given of page creation when the one-sided distance M is an arbitrary odd number of 3 or more. Here, the number of ring-shaped page buffers is 2M (2M images).

In this embodiment, the order of printing (12) for double-sided printing is as follows: (a) Starting from even numbered pages, printing alternately even numbered pages and then odd numbered pages.

(b) After printing a certain even-numbered page (referred to as page n), print an odd-numbered page (page n-1), which is the reverse side of the previous even-numbered page, on the Mth page.

(c) Look at the printing order of every other page, focus on only even-numbered pages or only odd-numbered pages, and print continuously.

There is a particular thing.

To paraphrase (a) to (c) mentioned above, ``Print the even-numbered pages first, advance the even-numbered pages by M pages from the odd-numbered pages, and print the even-numbered pages and odd-numbered pages alternately.'' Become. This displacement of M pages occurs because the sheets go around the conveyance loop. Therefore, in order to realize the order of page printing in this embodiment, the even numbered page group is advanced in phase by M pages than the odd numbered page group, and the ring-shaped pager, F3-4, . 1: All you need to do is create one.

I-Statement 1. (How to prepare a paper to meet the requirements) 1
10 is written as j11 to -1 below.

(2) When finishing the creation of several vanes and moving on to creating even-numbered pages, turn 49 in the opposite direction to the 11n order (image printing) and create an even-numbered 2-page in the M-th page buffer.

■ When moving from an even page to creating an odd page, print the page 1) Create an odd page in the 0 + 2 1] ・ζ-zipuffer.

This method) Order ■ From 1, even numbered pages are M first than odd numbered pages.
A? - You can advance only by . Also, hands; 11n
(1) From this point on, the order of pages can be correctly continued, taking into account A'T number of pages and even numbered pages. Furthermore, since the number of page buffers in the ring-shaped page buffer 3-4 is an even number and the double-sided spacing M is an odd number, even pages and odd pages are printed alternately. ) is maintained, 711-.

That is, by these steps (1) and (2), the double-sided printing of this embodiment is correctly realized.

FIG. 6 is a schematic diagram showing the structure of one page buffer included in the ring-shaped page buffer 3-4. here,
8-1 is a page presence/absence flag that indicates whether page information has been created in this page buffer, and indicates either "Yes" or "No." 6-2 indicates whether page information has been created in this page buffer. A page even-odd index indicating whether the page to be displayed is an even page or an odd page,
Even and odd pages are shown alternately. 6-31
This is an area where actual printing information is registered.

Explain the actual printing procedure to Shio.

FIG. 7 is a flowchart showing the initialization procedure performed by the CPU 3-3 (see FIG. 3). Prior to printing, the CPU 3-3 stores the ring-shaped page buffer 3-4. Set pointer 3-7. The page number counter 3-8 and print pointer 3-8 are initialized. This initialization procedure is as follows.

First, the page presence/absence flag 6-1 of all the di-buffers in the ring-shaped page buffer 3-4 is set to "absent" (15) (steps 7-1 to ?-3).

Next, set a page buffer with an appropriate page even/odd index to the set pointer; 3-7.
-4).

The page number counter 3-8 is set to 0 (2 steps 7-5).

The print pointer 3-9 is set with the M number 1 closing buffer from the set pointer 3-7 in the direction opposite to the print forward direction (step 7-6).

After completing the initialization in this way, the CPU 3-3 starts creating a page.

The eighth period is a flowchart showing the procedure for creating a page.

In condition determination steps 8-1 to 8-3, new pages are not created in the page buffer of pages that have not been printed yet.

In condition determination step 8-4, it is determined whether page creation is complete.

If there is data in MT3-IJ-, in step 8-5, CPU 3-3 sends data to T3-I via device 3-2.
The information (16) of J- is read, analyzed, and page information is created in the page buffer indicated by the set pointer 3-7. Here, creating page information means registering printing preferences in the area 6-3 and crossing the page presence/absence flag 6-1 by 90.

In step 8-6, the page number counter 3-8 is updated.

In steps 8-7 to 8-9, the set pointer 3-9 of the page buffer for creating the next page information is set. For this purpose, either step 8-8 or 8-8 is selected depending on whether the page created in step 8-5 is an even page or an odd page.

In step 8-8, the above-mentioned page creation method 111
Update the set pointer based on R■.

In step 8-9, the page creation procedure described
Updates the set pointer based on .

Set pointer 3 in step 8-8 or 8-9
After updating -7, control returns to step 8-1.

Further, in step 8-4, if W1 determines that the print information on MT3-1 has been completed, steps 8 to 11
control is transferred to the judgment of

In step 8-)1, the image even/odd index 6-2 of the closing buffer indicated by the set pointer 3-7 is checked, and if it is an odd closing page, page creation is terminated. If it is an even numbered page, control is transferred to step 8-12.

In step 8-12, completely blank page information is created in the page buffer indicated by set pointer 3-7. In step 8-12, when the print information of MT3-1 ends at an odd page (kA'-ji), a dummy closing page is printed on the next even page (k+1 page).
means to create a

In this embodiment, even-numbered pages are printed before odd-numbered pages, and paper is fed when even-numbered pages are printed. Therefore, dummy (k+1 pages) to be printed in advance.
If there is no sheet, the sheet on which page 1 and page +1 are to be printed will not be fed. That is, for page k, a toner image is formed on drum l-31-, but since there is no paper to which it should be transferred, the page will not be printed as a result.

Judgment in step 8-11 and step 8-1
By the processing in step 2, even if the print information of MT3-1 and J2 ends on an odd numbered page, the above-mentioned page omission can be prevented by creating a dummy even numbered page. Further, if the last page is an even numbered page, printing can be performed correctly up to the last page.

If it is determined in steps 8-1 to 8-3 that page creation is not possible, the process enters a waiting state in step 8-10. This suspends page creation only while one page is being printed, thereby preventing unprinted pages from being destroyed by newly created pages.

Note that, prior to printing, the CPU 3-3 creates pages rI and J. This is a measure to compensate for the difference between the order of pages created in this embodiment and the order of pages printed. Then, after page creation is completed, printing of the page is started. This ``L'' is the group ``J'' in the conditional judgment step ``3-1.''
(+~ (i.e., the maximum number of images that simultaneously pretend to exist in the page buffer?).
#4 The conditions to be met are described below in 1.1 (.

In this embodiment, page creation and closing page printing are performed in parallel. Therefore, if you do not limit the number of pages that exist simultaneously in the page buffer, new pages will be created for pages that have not yet been printed, resulting in missing images and page order errors. cause it to occur.

Therefore, consider the maximum number of images (+i'i) that can be simultaneously allowed to exist in the page buffer. In this embodiment, printing of even pages precedes printing of odd pages, so creating too many pages A new page is created on an unprinted odd-numbered image.The new page created at the 7th page of a certain odd-page text is the Q+2M page (odd number) in this embodiment.

In order to prevent this 1st sentence page from being destroyed while remaining unprinted, it is necessary to
It is sufficient to avoid creating M〆-ji. In this case, the page existing in page/゛'Zuffer-1- is
Odd numbered pages (total (M+1)/2 pages) from ji (odd number) to memorization + M-1 page (odd number), and memorization + M + 1
A total of 3 pages (even number) with writing + 2 M - 1 page (even number) with i-type clamped pages (total M - 1 page)
It is M/2-1/2 page. To explain this further,
The result is as shown below.

Printed
The page (odd) that has not yet been created and r%J has been printed represents an odd numbered page.

Next, we will consider the I role and small I role of the images φ that are simultaneously created in the page buffer 1-.

A certain bathing woman page number M is 41! Then, the pages ntr before and after m pages in the page creation and printing order:
, m + M page (even number) 1m page (odd hook) 1m 10a + 2
2-di (even number),...

When m+M pages (even number) are being printed, the pages that must exist at least in the page buffer are the odd numbered pages that have been created in the page buffer but have not been printed yet, and the even numbered page that is currently being printed. .

This is from the mth page (odd number) to the m+M-1th page (
(odd number) to odd numbered pages (total (M+1)/2 pages)
and the total of the m+M page (even number) (M+1)/2+
One page. The even pages before the m+M-2th page (even number) and the odd pages before the m2th page (odd number) have all been printed, and there is no need for them to exist in the page buffer J2.

Next, consider the minimum number of pages that must be present in the i-jbuff γ during the printing of m pages (odd number).

In order to print m10M+2 pages (even number) after page m (odd number), at the end of printing page m (odd number), after the mth page (odd number), add 1 page to the m10th page (odd number).
The total (m+3)/2 pages of the odd numbered pages (odd pages being printed or unprinted) leading up to , and the total (M+3)/2+1 pages of the m+M+2th page (even number) must exist in the page buffer. Must be.

From the above, the minimum number of pages that should simultaneously exist in the page buffer is (M+1)/2+2.

If this number of pages does not exist in the page buffer when printing even-numbered pages, continuous double-sided printing will not be performed.

Therefore, in condition determination step 8-1, it is determined whether or not to create a page. The range of No. 1 (that is, the number of pages allowed to exist simultaneously in the page buffer) must be between (M+1)/2+2 and 3M/2-1/2. To further explain this, the following As shown.

\C odd) (odd) (odd) (odd) However, the page ``chi'' has already been printed and is not already in the page buffer 1- Figure 9 is a flowchart showing the printing procedure.

After step 9-1, CPt13-3 sets page presence/absence flag 1 of the page buffer indicated by print pointer 3-9.
3-1 is checked, and if it is "broken", it is determined that a page to be printed exists, and printing is performed in steps 8-2 and subsequent steps.

In step 9-2, the CPU 3-3 instructs the print hardware 3-5 to the zipper (ie, the page to be printed) indicated by the print pointer 3-9.

In the step 8-3, the CPU 3-3 is connected to the printing hardware 3-5. A print command is issued to the printing device 3-6.

In step 9-4, the printing hardware 3-5 transfers the page information tμ of the page buffer instructed by the CPU 3-3 in step 8-2 to the printing device 3-6, and the printing device 3-6 transfers the page information tμ to the printing device 3-6. print.

At this time, paper feeding is performed only for even-numbered pages.

Note that since the CPU 3-3 is not involved in this printing itself, the CPU 3-3 performs the page creation procedure while one page is being printed. When printing of one page is completed, control is transferred to step 9-5.

In step 9-5, the CPU 3-3 sets the image presence/absence flag 6-1 of the R-zi buffer (that is, the page immediately after printing is completed) indicated by the print pointer 3-9 to "absent".

In step 9-6, the power value of page number counter 3-8 is decreased by one.

In step 9-7, page number counter 3-8 is 0.
It is checked whether the value is 0 or not, and if it is 0, printing is ended. If it is not 0, there is still a closing page to be printed, so control is transferred to step 9-8.

In step 9-8, the print pointer 3-9 is advanced to the next page buffer, and the process returns to step 9-1. Then, if it is determined in step 9-1 that there are no pages to be printed, control is transferred to step 8-9.

In step 9-8, the CPU 3-3 instructs the printing hardware 3 to print a blank page for this page.
-5 and the printing device 3-6. Here, printing a blank page means printing one completely blank page or interrupting printing only for the time it takes to print one page, as described above.

In step 9-10, the printing hardware 3-5 and printing device 3-6 print a blank page.

The CPU 3-3 creates a page during this time as in step 8-4.

Note that blank pages are printed for pages whose page presence/absence flag is "absent" in step 9-1.9-9.9-10, as described above, when even numbered pages and blank pages are printed immediately after printing starts. This is because it is necessary to alternately print (27) and also to alternately print an rjq white page and a tj number page just before the end of printing.

FIG. 1O is a schematic diagram showing a modification of the ring-shaped page/henceforth shown in FIG. 6. This figure 11.10-1 is 6
-1 is the same page presence/absence flag, 10-2 is the page even-odd index like 8-2, and 10-5 is the print information registration area of the actual page, same as 6-3. The newly added numeral 10-3 is a next cent page pointer indicating the page/゛ and the next page to be created.

Further, lo-4 is a next print end pointer indicating the page buffer to be printed next.

In the page creation procedure and page printing procedure, the center pointer 3-7 and print pointer 3-8 are updated.
This can be done using both pointers 10-3 and 1.0-4 mentioned above.

The next set pointer 10-3 of each page buffer is set to an appropriate value ((r+) according to the even page or odd page of the page even/odd index 10-2 in the page buffer. The set page pointer 10-3 contains the current page/head (28), the Mth page buffer counting backward from the mark I111110, or the next set pointer 1 of an even page.
The +2nd page buffer counting from the current page buffer in the printing order is set in O-3.

Thus, - the already mentioned pointers 10-3 and 10-4
By adding this, it is possible to simplify updating of the set pointer 3-7, especially when creating a page.

FIG. 11 shows the set pointer update procedure (
An example will be shown in which steps 8-7.8-8.8-9) are updated using the next set end pointer 10-3. That is, 8-7, 8-8, and 8-9 shown in the north of FIG. 11 are the set pointer update procedures in FIG. 8, and 11-1 shown in the lower part uses the next set pointer 10-3. This is a set pointer update procedure. Even when this step 11-1 is used, the previously described page creation procedures (1) and (2) are satisfied, and the order of the pages on the printed sheets is correct.

FIG. 12 shows an example in which the print pointer 3-8 of the printing procedure in FIG.
2-1).

1-, as described in FIGS. 11 and 12, by using the pointers 10-3 and 10-4, even when the page buffer 3-4 is not a ring-shaped hardware. , it is possible to create and print pages without any trouble.

As explained above, according to the first invention, it is possible to change the printing control procedure as necessary and thereby perform double-sided printing, which enables efficient and versatile recording. You can get the equipment.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a sheet conveyance system of a duplex printing apparatus which is an embodiment of the present invention, and FIG. 2 shows the conveyance system shown in FIG. 1 and the state of sheets flowing through the conveyance system. ! Schematic diagram showing 1, 3rd
The figure is a schematic diagram of an offline printing system to which the present invention is applied, Figures 4 and 5 are conceptual diagrams showing page order control during double-sided printing, Figure 6 is a structural diagram of the R-zibuffer, and Figure 7 is an initial FIG. 8 is a flowchart showing the page creation procedure, FIG. 9 is a flowchart showing the printing procedure, FIG. 10 is a structural diagram showing a modification of the page buffer, and FIG. The figure is a flowchart of a partially modified page creation procedure), and FIG. 12 is a flowchart of a partially modified printing procedure. 1-1... Paper feed section, 1-2... Pre-transfer conveyance path, 1-3... Drum, 1-4... Transfer charger, 1-5... Pre-fixing conveyance path, 1-6... Fixing device, 1-7... Pre-fixing conveyance path, 1-8... Branching mechanism, 1-8... Pre-reversing conveyance path, 1-1O... Reversing mechanism, 1 -II... Conveyance path before reversal, (31) 1-12... Conveyance path before smoother, 1-13... Smoother, 2-1... Sheet conveyance loop, 2-Q, - 1-2-2-5...Sheet being transported b℃
Paper, 3-1...Magnetic tape (MT), 3-2...Magnetic information converter, 3-3...Central processing unit (CPU), 3-4...Linked Hesy buffer, 3- 5... Printing hardware, 3-6... Printing device, 3-7... Set pointer, 3-8... Page number counter, 3-9... Print pointer, 4-1 to 4 -4...Arrow, 5-1 to 5-4...Arrow, 6-1...Page presence/absence flag, 6-2...Page even-odd index, 6-3...Print information registration area, 7-1~? -6, 8-1 to 8-12. 9-1 to 9-1O... Control step, (32) 10-1... Page presence/absence flag, 10-2... Page even/odd index, 10-3... Next cent page pointer, lo -4・
...Next print page pointer, 10-5...Print information registration area, +1-1.12-1...Control step. Patent applicant Canon Co., Ltd. Figure 2 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1) A buffer memory for registering recording information +1, a first means for writing the recording information into the buffer memory in a predetermined l1tl' number pattern, and a first means for writing the recording information into the buffer memory in parallel with the writing. 2. A recording apparatus comprising: second means for reading out the recording information from the buffer memory in a predetermined order pattern W when writing, and capable of double-sided recording. 2) Claim 1 J is characterized by comprising means for controlling so that a predetermined page relationship is maintained between the front and back surfaces of the recording sheet I and between the sheets.
The recording device described in I″i.