JPH0239966A - Perfect printing control system - Google Patents

Abstract

PURPOSE:To make the number of passes variable instead of being fixed and thereby increase perfect printing speed in various sizes by installing a device to set an optimal number of passes existing in a paper reversing mechanism in accordance with the size of a cutform and a device to prepare a printing pattern of each page to be printed on the both sides of each cutform in the sequential printing order according to the optimum number of passes. CONSTITUTION:In a printer control section, a device to set an optimal number of passes existing in a paper inversion mechanism 15 in accordance with the size of a cutform. A device to prepare a printing pattern 22 prepares a printing pattern of each single page to be printed on the both sides of a cutform in the sequential printing order corresponding to the determined number of passes. A printing control device 23 controls the feed of a cutform and the reversing and discharge of the paper in the sequential printing order corresponding to the determined number of passes. In addition, the printing control device 23 controls the perfect printing of a printing pattern of a single page prepared by a printing pattern preparation device 22 onto each cutform.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a double-sided printing control method in a cut paper printer that is equipped with a paper reversing mechanism and performs double-sided printing on cut paper of various sizes cut to a standard size, without fixing the number of passes. The purpose is to increase the duplex printing speed for various sizes by setting the optimum number of passes according to the cut paper size. In a duplex printing control method for a cut paper printer equipped with a printer control unit that controls printing operations of a printer mechanism unit, means for setting an optimal number of passes existing in a paper reversing mechanism corresponding to a cut paper size; A means for creating a printing pattern for each page to be printed on both sides of each cut sheet according to the printing order corresponding to the number of sheets, and controlling feeding, reversing, and paper ejection of each cut sheet according to the printing order corresponding to the optimal number of passes. The printer control section is configured to include means for controlling double-sided printing of the printing pattern on each cut sheet in a predetermined printing order.

[Industrial application field]

The present invention provides a double-sided printing control method for a cut paper printer that is equipped with a paper reversing mechanism and performs double-sided printing on cut sheets of various sizes cut to standard sizes [Prior art] Cut paper printers have been attracting attention in recent years because they are suitable for outputting various documents because they print out the print content directly on paper of the desired size, and they are easy to store and manage. .

When double-sided printing is performed on cut sheets in this cut sheet printer, the number of passes existing in the paper reversing mechanism is fixed, and double-sided printing is performed on each cut sheet at the same speed regardless of the paper size.

FIG. 7 shows a double-sided printing control system in such a conventional cut paper printer when the number of passes in the paper reversing mechanism is one. In Figure 7,
Reference numeral 41 designates a printing section including a photosensitive drum 411, 42 a paper reversing mechanism, 43A and 43B a paper transport section for transporting cut sheets, 44 a hopper, and 45 a stacker. Hopper 4
A plurality of sets of stackers 4 and stackers 45 are provided depending on the paper size, and one set is shown in the figure. The length of the paper reversing mechanism 42 is determined according to the length of the maximum supported paper. Reference numeral 40 denotes a printer mechanism section of a cut paper printer constituted by the above-mentioned mechanisms, and is controlled by a printer control section (not shown) to print on both sides of a cut paper.

Next, the double-sided printing operation of the cut paper printer shown in FIG. 7 will be explained. Note that the following double-sided printing operation is common to the double-sided printing operation for each paper size.

(1) A sheet of cut paper of a specified paper size is taken out from the hopper 44 and transported to the printing section 41 by the paper transport section 43A. The transport unit 41 first prints the print pattern of the second page (hereinafter the Xth page is indicated by P and X) (see FIG. 7(a)
)).

(2) When the printing of the print pattern P and 2 is completed, the cut paper is reversed by the paper reversing mechanism 42 (FIG. 7(b)).

■ Send the reversed cut sheet to the printing section 41 and press P.

The printing pattern of P and 1 is printed on the opposite side to the printing surface of 2 (FIG. 7(C)).

(2) The cut paper printed on both sides is discharged to the stacker 45 (FIG. 6(d)).

■ Double-sided printing is performed for the second and subsequent cut sheets in the same manner. As a result, as shown in the stacker 45 in FIG. 6(d), each cut sheet is printed on both sides and stacked in a face-down manner with P and 1 at the bottom.

In the face amplifier method in which sheets are stacked such that P,1 is placed on top, the print pattern of P,1 is printed first, and after the paper is reversed, the print pattern of P,2 is printed. When stacking on the stacker 45, the first sheet is placed on top, and the subsequent sheets are stacked below it. As a result, P and 1 are stacked at the top, contrary to the stacking method shown in FIG. 6(d).

[Problem to be solved by the invention]

Cut paper printers that are equipped with a conventional paper flipping mechanism and print on both sides of the cut are designed with the length of the paper flipping mechanism at the maximum supported paper size, as mentioned above, so paper flipping is possible regardless of the paper size of the cut paper. The number of passes in the mechanism was fixed, and both sides were printed at the same printing speed.

For this reason, when printing on one side, the smaller the paper size, the faster the printing speed will be, while when printing on both sides, even if the paper size is smaller than the maximum supported paper size, the printing speed will be faster for both sides at the maximum supported paper size. There was a problem that the printing speed was not faster than the printing speed, and the double-sided printing processing efficiency was poor when the paper size was smaller than the maximum supported paper size.

The present invention makes the number of passes during double-sided printing variable instead of fixed, and performs double-sided printing by setting the optimal number of passes that match the paper size of the cut paper, thereby achieving double-sided printing speeds for various paper sizes. The purpose of the present invention is to provide an improved printing control method that improves the performance.

[Means to solve the problem]

With conventional duplex printing control methods, printing was performed at the same speed as when printing on the maximum supported paper, regardless of the paper size. Therefore, when printing a cut sheet of a size smaller than the maximum support sheet, a space is created between the cut sheet and the following cut sheet in the paper reversing mechanism, which reduces printing efficiency. The present invention focuses on this point, and sets the optimal number of passes for each paper size by making the number of passes in the paper reversing mechanism variable during duplex printing, rather than fixing it. By performing double-sided printing, the speed of double-sided printing on various paper sizes is improved.

Hereinafter, the solution adopted by the present invention to solve the above-mentioned problems will be explained with reference to FIG.

FIG. 1 is a block diagram showing the basic configuration of the present invention.

In FIG. 1, reference numeral 10 denotes a printer mechanism unit, which includes a hopper 12 for storing cut sheets 11 therein, paper transport sections 13A and 13B for transporting cut sheets 11, and a photosensitive drum 141, and performs single-sided or double-sided printing on cut sheets. It is equipped with various mechanisms such as a printing section 14, a paper reversing mechanism 15 for reversing the paper during double-sided printing, and a stacker 16 for storing the printed cut sheets 11, and performs single-sided or double-sided printing on each cut sheet canted to a standard size. . In addition, when it is necessary to distinguish each cut sheet, use the cut sheet 11 with a suffix added to the code "11".
+, llz, etc. In addition, hopper 12
A stacker 16 and a stacker 16 are provided for each paper size, but when it is necessary to distinguish between them, a subscript is added to distinguish them as in the case of cut paper.

Reference numeral 20 denotes a printer control unit that controls the single-sided printing or double-sided printing operation performed by the printer mechanism unit 10.

In the printer control section, reference numeral 21 denotes an optimum pass number setting means, which controls the paper reversing mechanism 1 according to the paper size of the cut paper.
Set the optimal number of passes within 5.

Reference numeral 22 denotes a print pattern creation means that creates a print pattern for each one page to be printed on both sides of each cut sheet according to the printing order corresponding to the set number of passes.

Reference numeral 23 denotes a print control means that controls the feeding, paper reversal, and ejection of each cut sheet according to the printing order corresponding to the set number of passes, and prints each one page created by the print pattern creation means 22. Control is performed to print patterns on both sides of each cut sheet in a predetermined printing order.

30 is a host computer (hereinafter referred to as HO3T), which exchanges various initialization processing commands and data required for printing with the cut paper printer. Hereinafter, with reference to FIGS. 2 and 3, the operation when performing double-sided printing will be described. FIG. 2 is an explanatory diagram of the optimal number of passes corresponding to the paper size, and FIG. 3 is an explanatory diagram of the double-sided printing control method for each number of passes.

From the configurations of the print control mechanism 10 and paper reversing mechanism 14, the maximum supported paper size that the paper reversing mechanism 14 can support, the optimal number of passes that can be present in the paper reversing mechanism 15, and the optimal number of passes for each paper size are determined. Ru.

Column (A) in Figure 2 indicates that the maximum supported paper size is A.
(B ) column shows the optimal number of passes for each paper size in the paper reversing mechanism 15, which is configured so that the number of passes for the maximum support paper size A3 is two.

Information regarding the optimal number of passes corresponding to each paper size existing in the paper reversing mechanism 15 determined in this way is sent to the cut paper printer from the HO3T30 during initialization processing, and is sent to the optimal number of passes setting means 21. Retained.

In the cut paper printer, double-sided printing control is performed depending on whether the number of passes existing in the paper reversing mechanism 15 is one, two, three, etc. Figure 3 shows the double-sided printing control system in the case of the face-down method.
) is when the number of passes is 1, and (B) is when the number of passes is 2.
In the case of 3 sheets, FIG. 2C shows each double-sided printing control method when the number of passes is 3 sheets. The algorithms of these double-sided printing control systems are related to the number of passes and are not related to paper size. Furthermore, as will be explained in detail in the embodiment section, even if the number of passes existing in the paper reversing mechanism 15 changes, the duplex printing control algorithm is the same.
Hereinafter, the double-sided printing control method of the present invention will be described using an example in which the number of passes is two, as shown in FIG.

■ Initialization processing for the cut paper printer is performed from the HO3T30, and at that time, information regarding the optimal number of passes for each paper size is sent to the optimal number of passes setting means 21 and held there. (You may also set it permanently.)

(2) When a paper size is specified by an instruction from the HO3T 30 or a default value of the cut paper printing device, the print control means 23 learns the optimum number of passes for the specified paper size from the optimum number of passes setting means 21.

■ Now, assuming that the number of sheets passed for the specified paper size is two, the print control means 23 prints the first sheet from the hopper 12 of the specified paper size according to the duplex printing control algorithm when the number of sheets passed is two. cut paper 111
is taken out and transported to the printing department 4 by the paper transport section 13A.

On the other hand, when the print pattern creation means 22 learns the number of passes for the specified paper size from the optimum number of passes setting means 2I, it prints each page sent from the HO3T30 according to the duplex printing control algorithm when the number of passes is two. First, a print pattern for one page of P and 2 is created from the data.

■ When the print pattern creation means 22 finishes creating the print pattern P, 2, the print control means 23 controls the printing section 14.
to control the cut paper 11. The printing pattern P, 2 created by the printing pattern creation means 22 is printed on the printing surface of (FIG. 3(B) (a)).

■ Cut paper 11. When the printing of P, 2 is completed, the print control means 23 causes the paper reversing mechanism 15 to rotate the cut paper 1
1. , and transfer the next second cut sheet 11□ to hopper 1.
2 to the printing unit 14 ((b) in Fig. 3(B))
.

■ During this time, the printing pattern creation means 22, HO3T3
P according to a predetermined duplex printing control algorithm from among the print data of each page sent from 0.

Create a print pattern for one page in step 4.

■ When the creation of the printing patterns P and 4 is completed and the feeding of the cut paper 11□ is finished, the print control means 23 controls the printing unit 14 to print on one side of the second cut paper 11z. The printing pattern P, 4 created by the pattern creation means 22 is printed ((b) in FIG. 3(B)).

(2) When the printing of P and 4 on the cut sheet 11□ is completed, the print control means 23 instructs the paper reversing mechanism 15 to reverse the cut sheet 11z ((C) in FIG. 3(B)).

[Phase] During this time, the print pattern creation means 22 prints P from among the print data of each page sent from the HO3T 30 according to a predetermined double-sided printing algorithm.

Create a print pattern for one page of 1. P.

When the printing pattern (3) is created and the inverted cut sheet 11+ is fed into the printing section 14, the printing control means 2
3 controls the printing unit 14 to print the print pattern P, 1 on the opposite side of the first sheet of cut paper 111 that has been reversed ((d) in FIG. 3(B)). As a result, the first cut paper 11. niP.

The contents of 1, P, and 2 are printed on both sides.

■ First cut paper 11. When the printing of P, 1 is completed, the print control means 23 prints the first cut sheet
1 is discharged to the stun force 16 and stacked in a face-down manner. During this time, the print pattern creation means 22 creates a print pattern for one page, P, 3, from the print data of each page sent from the HO3T 30, according to a predetermined double-sided printing algorithm. The print pattern P, 3 has been created and the inverted cut sheet 112 is sent to the printing unit 14.
When the paper is fed inside, the print control means 23 controls the printing unit 14 to print the printing pattern P, 3 on the opposite side of the reversed second cut paper 112 (see FIG. 3). B
) of (e)). As a result, the contents of P, 3 and P, 4 are printed on both sides of the second cut sheet 112.

■ When the printing of P and 3 on the second cut paper 11□ is completed, the print control means 23 prints the second cut paper 11
2 are discharged to the stacker 16 and stacked face down. As a result, as shown in Figure 3 (B), the first sheet P and 1 are at the bottom, and the second and third double-sided printed sheets are placed at the top in page order. stacked so that

The explanation has been given using an example where the number of sheets passed is 2 and stacking is performed in the face-down method. However, when stacking in the face-up method, P and 1 are printed on the first cut paper 111 → cut paper Flip lI, second cut paper 11. Print P, 3 on → cut paper 11. Reverse the cut l1g along with it → Print P and 2 on the opposite side of the 11th cut paper 111 → Eject the 11th cut paper lit and stack it in the face-up method, and print on the opposite side of the 2nd cut paper II2 Print P and 4 on the side → 22nd sheet cut paper 1
Double-sided printing is performed by ejecting 1□ sheets and stacking them in a face-up method. As a result, the first P,
1 is on top, and the second and third double-sided printed cut sheets are stacked on the bottom in page order.

When the number of passes is 1 or 3, double-sided printing is performed using the control method shown in Figures 3 (A) and (C), but the control details are as described above when the number of passes is 2. Since this is obvious from the double-sided printing control method, a description thereof will be omitted.

As explained above, the number of passes in the paper reversing mechanism during duplex printing is not fixed, but is variable, setting the optimal number of passes for each paper size, and duplex printing is performed with the optimal number of passes matching that paper size. This enables highly efficient duplex printing without reducing the printing area per unit time even when printing on both sides of cut paper that is smaller than the maximum supported paper size, improving the duplex printing speed for cut paper with small paper sizes. can be done.

〔Example〕

Embodiments of the present invention will be described with reference to FIGS. 2 to 6. , FIG. 4 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIG. 5 is a page control table (PST) used in the embodiment.
FIG. 6 is a flowchart of the double-sided printing process of the same embodiment. 2 and 3 are as already explained.

(A) Configuration of Example In FIG. 4, printer mechanism section 10, cut paper 11,
Hopper 12 (12, -12,), paper transport sections 13A and 13B, printing section 14, photosensitive drum 141, paper reversing mechanism 15, stacker 16 (16, - 16.), printer control section 20, optimal pass number setting means 21, print pattern creation means 22, print control means 23, and host computer (HO3T) 30 are as described in FIG.

In the optimum pass number setting means 21, reference numeral 211 is a pass number management table (hereinafter referred to as PCT);
Information regarding the optimal number of passes suitable for each paper size in No. 5 is stored. An example of the contents of the pass number management information stored in the PCT 211 is shown in FIG. When the maximum supported paper size of the paper reversing mechanism 15 is A3 and the number of passes is one, the contents of column (A) are stored, and when the number of passes is two, the contents of column (B) are stored. In this embodiment, it is assumed that the contents of (B)l are stored. Since the pass number management information of the PCT 211 is fixedly determined by the configuration of the paper reversing mechanism 15, it may be fixedly stored in the PCT 211, but in this embodiment, the HO3
It is assumed that HO3 is sent from T30 at the initial stage or during processing performed by T30.

In the print pattern creation means 22, 221 is a bitmap memory (hereinafter referred to as BMM) in which the print data of each page is expanded into a print pattern and stored.

222 is a character generator (hereinafter referred to as CG) in which character patterns of various characters are stored.

223 is a pointer/counter table (hereinafter referred to as PTCT) that stores the values of each pointer (FTP, PNP, PBM, etc.) and the number of printed pages for extracting the print data of each page according to the duplex printing control algorithm for a predetermined number of passes. A page counter (hereinafter referred to as PCNT) is stored (each of these pointers and PCNT will be explained later in the page control table PST).

224 is a second processor (hereinafter referred to as second MPU);
Performs printing pattern development processing for each page.

In the print control means 23, 231 is a host interface section (hereinafter referred to as HIF section), which performs processing for exchanging commands and data with the HO3T30.

232 is an intermediate buffer in which data received from HO3T30 is temporarily stored.

233 is a character code conversion unit that converts each character data in the print data received from the HO3T30 into an internal code indicating the address of the corresponding character pattern in the CG 222.

234 is a page buffer (hereinafter referred to as PB) in which character data of each page converted into internal code is stored.

235 is a page control table (Page 5equen
seTable (hereinafter referred to as PST), page information indicating the position of each page on the PB 234 is sequentially stored in order from P, 1, as shown in FIG. In FIG. 5, P T P (Pass
Top Pointer), PNP (Pass
Now Po1nter) and P B M (Pas
s Bottom Pointer) is each pointer for extracting the print data, that is, the character data, of each page according to the duplex printing algorithm for a predetermined number of passes, and its contents are as follows.

PTP: Indicates the address of the page information area of the first page, ie, P and I.

PNP: Indicates the address of the page information area to be subjected to the current printing pattern development process. This PNP is updated every time the printing pattern development process for one page is completed.

Regardless of the number of passes, it can be calculated from PNP=PTP+1.

PBM: Indicates the address of the final page information area for a predetermined number of passes. This PBM is updated every time a predetermined number of passes are completed. If the number of printed pages printed in one double-sided printing by the paper reversing mechanism 15 according to the optimal number of passes is PCNTN, then PBM=PTP+P
It is determined by CNTN-1. Note that this PCNTN is set in the page counter PCNT of the PTCT 223.

Note that the PST area has n pages as shown in the figure, and n
When +1 page worth of data is created, ps'rM again
The beginning of the area is used. In this way, the PSTSff area has a lymphatic buffer configuration.

236 is a print processing unit (hereinafter referred to as MC), which includes a hopper 12. ~127 selection and paper feed control,
Mechanical operations in the printer mechanism section 10, such as conveyance control of the cutter 11 of the paper conveyance sections 13A and 13B, control of the paper reversing mechanism 15, selection and paper ejection control of the stackers 16+ to 16A, printing operation control of the printing section 14, etc. control.

237 is a printer control unit (hereinafter referred to as PRC);
The print pattern of a predetermined page developed on the M221 is taken out and sent to the printing section 14 of the printer mechanism section IO, and the printing conditions such as the hopper to be used, the stacker, and the start time instructed by the first MPU 23B are sent to the MC236.

238 is a first processor (hereinafter referred to as 1MPU);
Controls the operation of each part in the print control means 23 and P
It updates the contents of the ST and controls the overall operation of the printer control section 20.

(B) Operation of the Embodiment Since the single-sided printing operation is performed in the same manner as the conventional one, the print control operation for the double-sided printing of the embodiment is performed by the paper reversing mechanism 15.
An example will be explained in which the number of passes is two.

Further, the stacking method is determined by the structure of the cut paper printer, and in this embodiment, it is assumed that it is a face-down method. Therefore, when the number of passes is 2, Fig. 3 (B
Double-sided printing is performed using the control method shown in ).

(i) Initialization Process HO3T30 performs initialization processing for the cut paper printer, and passes number management information of the PCT 211, paper size of cut paper, etc. are sent.

In this embodiment, the maximum supported size of the paper reversing mechanism 15 is A3, and the number of passes is two, so the number of passes management information in column (B) of FIG. 2 is sent. Also, if the paper size is different from the default value (A4), HO3T
In this embodiment, it is assumed that "B4" is designated as the paper size.

The pass number management information sent from the HO3T30 is received by the HIF unit 231, stored in the intermediate buffer 232, and then stored in the PCT 211 by the first MPU 23B.

When paper size B4 is specified from HO3T30,
The MPU 238 operates a hopper (1
The MC 236 is instructed via the PRC 237 to switch to the stacker (referred to as 162) and the stacker (referred to as 162).

Upon receiving this switching instruction, the MC 236 switches from the default value of the hopper (12) and stacker (16I) for paper size A4 to the 84-size hopper 12□ and stacker 16□.

In addition, the first MPU 238 has an optimum pass number setting means 234.
The optimum number of passes for the specified paper size B4 is detected by referring to the PCT 211 of . The optimum number of passes for paper size B4 is two, as shown in column (B) of FIG. 1st MPU23B
is the number of printed pages PCNTN printed by one double-sided printing by the paper reversing mechanism 15 based on this optimal number of passes.
(Optimal number of passes x 2) and PC of PTCT223
NT (Set in the page counter. The optimal number of passes is 2.
The print page PCNTN when the number of sheets is 4 (=2×2) pages.

The first MPU 238 records PTP at the beginning of the PST 235, PNP=FTP+1, PBM=PTP+PC
Calculate PNP and PBM from NTN (value of PCNT) - 1, and calculate PTP, PNP and PB of PTCT223.
Each pointer area of M is set as an initial value, and FTP=1 is set as the initial value.

■ When the above initialization process is completed, the print control means 23
The first MPU 23B of HO3 via the HIF unit 231
It exchanges commands with T30 and receives print data for each page in order from P and 1.

The print data of each page is received line by line, and one end is stored in the intermediate buffer 232.

The first MPO 238 instructs the character code conversion unit 233 to convert each character data in the received print data into CG2.
The address of the corresponding character pattern in PB 234 is converted into an internal code indicating the address and stored in a predetermined position of PB 234. Here, every time one page of print data is completed, the print data of P, 1 is sequentially
The page information on B234 is set in PST235. When the print data up to P.4 is completed,
As shown in FIG. 5, the page information on the PB234 of P, 1 to P, 4 is set sequentially, and the FTP is P,
Indicate the page information area of 1, PNP is P, 2
PBM points to the page information area of P, 4.

The process of receiving the print data of each page from the HO3T 30 and the process of sequentially setting each page information in the PST 235 are performed asynchronously with the double-sided printing process described below.

Hereinafter, with reference to the processing flowchart of FIG. 6, the double-sided printing process will be mainly explained according to its processing steps.

■ Processing S.

The second MPU 224 uses the P set in the PCPT 223.
Refer to the page information area of P, 2 of the PST 235 indicated by NP (-2), and wait for the completion of inputting the page information of P, 2, that is, the completion of inputting the print data for one page of P2 into the PB 234. wait. Inputting the print data of P and 2 to the PB 234 is performed by the above-mentioned input process (2).

When the page information of P, 2 is sent to the area specified by the PNP of the PST 235 as explained in the above ①, the second MPU 224 uses this page information to
The print data of P, 2 is taken out from 34. Then,
Using the internal code as an address, a corresponding character pattern is extracted from the CG 222, developed at a predetermined position on the 8MM 221, and notified to the first MPU 238.

■Processing S2 When the first MPU 23B finishes developing the print data for one page of P, 2, it instructs the PRC 237 to print the printing conditions, and causes it to print P, 2.

That is, the PRC 237 sends the printing conditions instructed by the first MPU 238 to the MC 236, and also sends the 8MM 22
Take out the printing patterns of P and 2 from 1 and print the printing part 1.
Supply to 4. The MC 236 takes out the first sheet of B4 cut paper 111 from the hopper 122 according to the printing conditions instructed by the PRC 237, feeds it to the printing section 14 by the paper conveying section 13A, and prints P, P, etc. on the printing surface of the cut paper 111.
2 print pattern ((a) in Figure 3(B))
).

■Processing Sol, 34, SS When P and 2 are printed on the first 84 cut sheets 111, the first MPU 238 determines whether PNP=PBM (processing S3). When printing P, 2, PNP=2
, PBM=4, so PNP<PBM and PN
P=PBM does not hold.

When P N P = P B M does not hold, the lMP
U238 increments PNP by two pages and PTCT22
PNP 3 is updated to PNP+2=4 (processing S4).

Next, the first MPU 23B determines whether the updated PNP is larger than the PBM (processing S5). Since PNP=4=PBM this time, PNP>PBM is denied and the process returns to the first process S1.

■ Processing St, Sz In the same way as the above-mentioned processing Sl, this time the updated PNP
(=4) indicates P, 4 print data is PB234
Wait until the input is completed. When the input of the print data of P and 4 to the PB234 is completed, the second MPU224
Extract the print data of P and 4 from 4 and set it to CG222
Then, each corresponding character pattern is obtained and developed at a predetermined position on the 8MM 221 (processing S).

On the other hand, the first MPU 238 outputs the cut paper 11. When the printing of cut sheets P and 2 is completed, an instruction is given to the MC 236 via the PRC 237 to control the paper reversing mechanism 15 and to control the paper reversing mechanism 15. Invert.

Next, when the first MPU 23B detects the completion of the expansion of the print data for 1 page of P and 4, it instructs the PRC 237 in the same way as in the above ■, and this time prints the second sheet of 84 cut sheets 11□. The paper is fed into the unit 14 and printing of P and 4 is performed (process S2, (b) in FIG. 3(B)).

■ Processing S3. S6 When P and 4 are printed on the second 84 cut sheets 11□, the first MPU 23B determines whether PNP=PBM holds true (processing S3). P, PN when printing 4
Since P=4, PNP=4=PBM holds true.

When PNP=PBM, the first MPU 23B sets PNP to F.
The process S+, ) is performed to update the value of TP (=1), and the process returns to the process S1.

■ Processing St, Sz In the same way as each processing Sl described above, this time the updated PN
P (=1) indicates P, 1 print data is PB
234 is completed (processing S1). PB23
When the input of the print data of 1 is completed, the 2nd
The MPU 224 takes out the print data of P, 1 from the PB 234, obtains each corresponding character pattern from the CG 222, and develops it at a predetermined position on the 8MM 221 (processing S).

On the other hand, the first MPU 238 instructs the MC 236 via the PRC 237 when the printing of P and 4 on the cut paper 11
1□ is also inverted ((C) in Figure 3 (B)).

Next, when the first MPU 238 detects the completion of the expansion of the print data for one page of P, 1, it instructs the PRC 237 in the same manner as in the above-mentioned ①, and this time, it instructs the PRC 237 to print the reversed first sheet of cut paper 11. is fed into the printing unit 14, P, 2
P on the printed side opposite to the printed side.

1 is printed (processing S2, (d) in FIG. 3(B)).

As a result, P is added to the first 84 cut paper lit.

■ and P, the contents of 2 are printed on both sides.

■ Processing 53-34 First cut paper 11. When double-sided printing of P, 1 and P, 2 is performed, the first MPU 23B prints PNP=PB.
It is determined whether M holds true (processing S,).

1st cut paper 11. When P is printed on the back side of , PN is printed on the back side of
Since P=1 and PBM=4, PNP=PBM does not hold.

When PNP=PBM does not hold, similarly to the above ■,
The first MPU 238 converts the PNP of the PTCT 223 into a PNP
It is updated to +2 (=3) (processing S4).

Next, the first MPU 23B determines whether the updated PNP is larger than the PBM (processing SS). PNP
Since PNP=3 and PBM=4, PNP>PBM is denied this time as well, and the process returns to the first process S1.

[Phase] Processing S,,S.

In the same way as each process S described above, this time the updated PN
The print data of P,3 specified by P (=3) is PB23
4. Wait for the input to be completed (processing S1). When the input of the print data of P and 3 to PB234 is completed, the second MP
U224 takes out the print data of P and 3 from PB234, obtains each corresponding character pattern from CG222, and prints 8M.
It is expanded to a predetermined position on M221 (processing Sl).

On the other hand, when the first MPU 238 completes double-sided printing of P, ■ and P, 2 on the first cut paper 11, the first MPU 238 sends the MC 23
6 and place the first cut sheet 11+ on the stacker 16□
The paper is ejected from the printer and stacked face-down.

Next, when the first MPU 23B detects the completion of development of the print data for one page of P and 3, it instructs the PRC 237 in the same manner as in the above-mentioned ①, and this time, the second cut sheet 22 which has been reversed is transferred to the printing section 14. Feed the paper inside the paper, and place P on the printing side opposite to the printing side of P and 4.

3 (process S2, (e) in FIG. 3(B)).

As a result, P, 3 and P are placed on the second cut paper 11□.
, 4 will be printed on both sides.

■ Processing S: l, S4 When double-sided printing of P, 3 and P, 4 is performed on the second cut paper 11□, the first MPO 238 prints PNP=
It is determined whether PBM is established (processing S3).

When printing P and 3 on the surface of the second cut paper 11□,
Since PNP=3 and PMB=4, PNP=PBM does not hold.

When PNP=PBM does not hold, similarly to the above ■,
The first MPU 23B converts the PNP of the PTCT 223 into a PNP
It is updated to +2 (=5) (processing S4).

Next, the first MPU 238 determines whether the updated PNT is larger than the PBM (processing S). This time, PNP=5 and PBM=4, so PNP>PBM holds true.

@ Processing S7, Ss, 39PNP>PBM
When this is established, the first MPO 238 updates the PTP (=1) of the PTCT 223 to PBM+1 (-5) (
Processing S7). Furthermore, PBM (=4) is PTP+PCNT
Update to N-1 (=8) (Se), PNP to FT
Update to P+1 (=6) (process 39).

Updated FTP, PNP and PBM like this
The second two cut sheets 113 and 11. which are fed to the paper reversing mechanism 15 are used as page information pointers in ST235. For P, 5-P.

8 will be printed on both sides. In this case, PBM is P,8
The page information area of FTP and PNP are specified first.
, 5 and P, 6.

The above has described an example in which the number of passes is two, but even when the number of passes is other than two, each pointer FTP, PNP
Then, the PBM is set and updated, and double-sided printing is performed on the number of cut sheets for each pass. For example, when the number of passes is three, the number of printed pages PCNTN=6. Therefore, initially FTP=I, PNP=FTP+-1=2, and PBM=PTP+PCNTN-1=6.

Thereafter, each time each page is printed according to the processing flowchart in FIG. 6, FTP and PNP are updated, and 3
When double-sided printing of the number of passes is completed, FTP, PNP and BM are as follows: FTP=7, PNP=8, PBM=12
, and double-sided printing is performed for the second pass number of three sheets.

Even if the paper size is different, if the number of passes is the same, double-sided printing is performed using the same procedure.

〔Effect of the invention〕

As explained above, according to the present invention, the number of passes in the paper reversing mechanism during duplex printing is not fixed, but is made variable so that the optimum number of passes is set for each paper size, and the optimum number of passes is set for each paper size. By performing double-sided printing based on the number of passes, it is possible to perform double-sided printing with high efficiency without reducing the print area per unit time even when printing on both sides of cut paper smaller than the maximum supported paper size, making it possible to perform double-sided printing with high efficiency without reducing the print area per unit time. It is possible to improve the speed of double-sided printing on paper.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the basic configuration of the present invention. Figure 2 is an explanatory diagram of the optimal number of passes corresponding to each paper size used in the present invention and one embodiment. Figure 3 is duplex printing control for each number of passes. Fig. 4 is an explanatory diagram of the configuration of an embodiment of the present invention; Fig. 5 is an explanatory diagram of the page control table (PST) used in the embodiment; Fig. 6 is a diagram of both sides of the embodiment. Print Processing Flowchart FIG. 7 is an explanatory diagram of a conventional double-sided printing control system. 1 and 4, 10...printer mechanism section, 11...force (12,,1
2□, etc.)...Hopper, 1...Paper transport section, 14...
・Printing section, 14, 15...Paper reversing mechanism, 16 (1
sheet paper, 12 3A, 13B l...photosensitive drum 6, . 16□, etc.)...Stacker, 20...Printer control unit, 21
...optimum pass number setting means, 211...pass number management table (PCT), 22...print pattern creation means, 221...bitmap memory (BMM),
222...Character generator (CG), 223...Pointer/counter table (PTCT), 224...Second processor (second MPU), 23...Print control means, 231...Host interface section (HIF section)
, 232... Intermediate buffer, 233... Character code expansion section, 234... Page buffer' (PB), 23
5...Page control table (PST), 236...
・Print processing unit (MC), 237...Printer control unit (
PRC), 238...first processor (first MPU)
, 30... host computer (HO3T). Figure 2: Optimal number of passes corresponding to each paper size used in the present invention and examples

Claims (1)

[Claims] 1. A printer mechanism unit (10) that is equipped with a paper reversing mechanism (15) and performs double-sided printing on cut paper cut to a standard size.
) and a printer control section (20) that controls the printing operation of the printer mechanism section (10). (B) an optimum pass number setting means (21) for setting the optimum number of passes existing in the reversing mechanism (15); (C) controlling the feeding, reversing, and ejecting of each cut sheet according to the printing order corresponding to the set optimal number of passes; death,
The printer control unit (20) is provided with a print control unit (23) for controlling double-sided printing of each one-page print pattern created by the print pattern creation unit (22) on each cut sheet in a predetermined printing order. A double-sided printing control system characterized by: