JP5440921B2 - Image forming apparatus and printing control method in image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus and a print control method in the image forming apparatus, and more particularly to an image forming apparatus and a print control method in the image forming apparatus that are characteristic of a double-sided printing technique for printing on both sides of a sheet.

  When printing and outputting a double-sided document in an image forming apparatus such as a copying machine, a multifunction peripheral, or a printer, the first side (front side) image and the second side (back side) image are printed on paper ( Image formation). Therefore, the image forming apparatus includes a paper reversing mechanism, and after printing the first side of the document on the paper, the paper is reversed by the paper reversing mechanism, and is fed again to print the second side of the original on the paper. Duplex printing is performed.

By the way, in the paper reversing mechanism, a path for reversing the paper is used. However, since this path needs a certain length, the reversal is such that the reversal of the preceding paper is finished and the subsequent paper is fed. When processing is performed, a time lag occurs between page printings by the time required to invert the paper. As a result, there arises a problem that the print output productivity inherent in the image forming apparatus cannot be sufficiently exhibited.
For this reason, image forming apparatuses that generally require high-speed processing have a double-sided printing function (mechanism) based on a so-called interleaf operation in which the next paper is printed while the paper is reversed. The printing productivity is improved (or not lowered) (see, for example, Patent Document 1).

10 to 12 are explanatory diagrams showing an outline of double-sided printing processing by an interleaf operation in a conventional image forming apparatus.
FIG. 10 is a diagram showing double-sided printing by an interleaf operation when printing two copies of a four-page document on a sheet and printing two copies (that is, printing a total of eight documents).
Here, symbol a is a sheet bundle, b is a sheet in a double-sided path that is a reverse path, and c is a diagram schematically showing a sheet discharged to a discharge tray. When double-sided printing is performed on a four-sheet original using a two-part interleaf operation, first, four of the scanned original images are continuously printed, that is, the first side of the first to fourth sheets is placed on the first to fourth sheets. Printing is continuously taken into a double-sided path which is a reverse path (see (1) to (5)). In the double-sided pass, the sheet is printed and conveyed every step, and here, the sheet is reversed after 5 steps and is set to the printing position again. In other words, the first sheet is printed on the first side of the first side of the first original, and then reversed after 5 steps to reach the printing position, where the second side of the first original is Printed (see (6)). The paper for which double-sided printing has been completed is discharged to a paper discharge tray as shown in c. Next, the first side of the fifth original (actually, the second printing start of the first original: hereinafter referred to as the total number of originals) is printed on paper (see (7)).
Thereafter, the second side of the second original at the head of the duplex pass and the first side of the sixth original are alternately printed on the next fed paper (see (8) to (13)). . When the printing of the first side of all the originals is completed in this way, the second side of the original is continuously printed on the paper in the double-sided path where the first side has been printed ((14) to). (See (17)).

FIG. 11 is a diagram showing an output operation of a single-side original / double-side original mixed document bundle in double-sided printing by interleaf operation when two copies of four originals are printed as in FIG. Reference numerals a, b, and c are the same as those in FIG.
In this example, it is assumed that double-sided originals and single-sided originals are alternately fed to the image reading unit. First, since the first sheet is a double-sided document, after printing the first side, the paper is reversed (see (2) to (5)), and the second side of the document is printed after 6 steps ((6) In the next step, the first sheet is printed on both sides of the first sheet, and the first sheet is printed on the sheet because the second document is a one-sided document (see FIG. The sheet is discharged in the next step (see (8)). Thereafter, this operation cycle is repeated alternately. In this example, 26 steps ((1) to (26)) are required to print a total of eight (4 sheets × 2 surfaces + 4 sheets × 1 surface = total 12 surfaces) originals. In other words, the efficiency is reduced by about half compared to the case where only double-sided originals are printed continuously.

FIG. 12 is a diagram showing an output operation of a single-side original / double-side original mixed document bundle in double-sided printing by an interleaf operation when two copies of four originals are printed. Reference numerals a, b, and c are the same as those in FIG.
In this example, it is assumed that only the second of four originals is a single-sided original and the rest is a double-sided original. First, since the first sheet is a double-sided original, the first side of the first double-sided original is printed on paper (see (2)), and then the paper is transported for each paper feeding step and after 5 steps. Is reversed (see (3) to (6)), and the second side of the first document is printed on paper (see (6)). Next, the first sheet is discharged onto the discharge tray, and at the same time, the first side of the second single-sided document is printed on the second sheet (see (7)). In the next step, the second sheet is discharged to the discharge tray (step 8). At the same time, the first side of the third original, which is a double-sided original, is printed on the first side of the third sheet, followed by the fourth original, the fifth original (the same as the first original). ) On the first side of the fourth and fifth sheets. Next, after printing on the second side of the third, fourth, and fifth sheets, the same as the first sheet, the sixth single-sided document (same as the second sheet) is printed. Print on the first side of the first sheet. Since double-sided originals are printed on the seventh and eighth sheets, the first side of the seventh sheet, the first side of the eighth sheet, the second side of the seventh sheet, and eight sheets Print in the order of the second side of the eye paper. In this example, 22 steps ((1) to (22)) are required to print on 8 sheets (6 sheets × 2 surfaces + 2 sheets × 1 surface = all 14 surfaces).

  10 to 12, the double-sided printing by the interleaf operation for the four originals is described. However, this is an example, and the number of originals is of course arbitrary.

  In the conventional double-sided printing by the double-sided interleaf operation, when printing a document in which a single-sided original and a double-sided original are mixed, if the first is a double-sided original, as shown in FIG. Both sides are printed on both sides of the first sheet, and then the next document is printed. Therefore, when printing a document in which a single-sided document and a double-sided document are mixed, double-sided printing by an interleaf operation is not sufficiently effective, and there is a problem that printing productivity is lowered.

  For example, one set of four originals are alternately printed on both sides and one side, that is, the first sheet: double-sided, the second sheet: single-sided: the third sheet: double-sided, the fourth sheet: single-sided printing that outputs two sets of originals In the case of jobs, there were the following problems. That is, in conventional double-sided printing (4-sheet interleaf operation double-sided printing: operation of continuously printing the first side of four sheets during double-sided printing), in order to print a total of 12 sides, FIG. As shown, a total of 26 steps are required. As a result, productivity is reduced to about half compared to a print job in which a single-side original and a double-side original are not mixed.

In addition, while the paper on which the first side of the double-sided document is printed moves in the double-sided path, there is a period during which the document is not actually printed. During this period, toner is generated due to idle rotation of the image forming process, particularly the developing unit. There is also a problem that there are concerns about adverse effects on the environment.
An attempt has been made to increase the productivity of double-sided printing by interleaf operation. For example, a technique for reducing loss by continuously printing several sheets immediately before the end of a print job is already known. Is not enough, and there is room for improvement.

  An object of the present invention is to improve printing productivity in a print job in which a single-side original and a double-side original are mixed in double-sided printing by an interleaf operation.

The present invention prints a double-sided document having a first side and a second side on both the first side and the second side of the paper, and prints a single-sided document having only the first side on the first side of the paper. an image forming apparatus for printing the part number of the original single-sided printing and are mixed, the sheet reversing path for conveying a printing unit, said printing unit by reversing the paper first side is printed in the two-sided document As long as it can be accommodated in the paper reversing path, the first side of the plurality of double-sided originals is continuously printed on the first side of the paper, and then the second side of the plurality of papers. Print control means for controlling to perform the process of printing the second side of the double-sided document and the process of printing the first side of the single-sided document on the first side of the paper in the arrangement order of the documents. The image forming apparatus is characterized.
Another invention of the present application is a double-sided printing in which a double-sided document having a first side and a second side is printed on both the first side and the second side of the paper, and a single-sided document having only the first side is a first side of the paper. a single-sided printing to be printed and print a part number of the document to be mixed in, a printing unit, a paper inverting path for conveying the printing unit by reversing the paper first side is printed in the two-sided document, the A printing control method for controlling printing of an original in an image forming apparatus having the first side of a plurality of double-sided originals continuously with the first side of the paper as long as it can be accommodated in the paper reversing path After performing the printing process, the process of printing the second side of the double-sided document on the second side of the plurality of sheets, and the process of printing the first side of the single-sided document on the first side of the sheet, A print control process for controlling to perform in the arrangement order of That.

  According to the image forming apparatus of the present invention, printing productivity can be improved in a print job in which a single-sided original and a double-sided original are mixed among double-sided printing by an interleaf operation.

2 is a simplified functional block diagram of a control device of the image forming apparatus according to the embodiment of the present invention. FIG. FIG. 2 is an explanatory diagram showing an outline of double-sided printing processing by an interleaf operation in the image forming apparatus of FIG. 1. FIG. 2 is an explanatory diagram showing an outline of double-sided printing processing by an interleaf operation in the image forming apparatus of FIG. 1. It is a flowchart which shows the whole process sequence of the interleaf operation | movement duplex printing process performed by the control apparatus in FIG. It is a flowchart which shows the procedure of the initial setting process performed by S101 in FIG. FIG. 6 is a diagram illustrating a sheet structure for registering information of each sheet used in the flowchart of FIG. 5. It is a flowchart which shows the procedure of the single-sided output process performed by S103 in FIG. It is a flowchart which shows the procedure of the 1st surface process performed by S104 in FIG. It is a flowchart which shows the procedure of the output process performed by S107 in FIG. It is explanatory drawing which shows the outline | summary of the double-sided printing process by the interleaf operation | movement in the image forming apparatus which concerns on a prior art example. It is explanatory drawing which shows the outline | summary of the double-sided printing process by the interleaf operation | movement in the image forming apparatus which concerns on a prior art example. It is explanatory drawing which shows the outline | summary of the double-sided printing process by the interleaf operation | movement in the image forming apparatus which concerns on a prior art example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a functional block diagram of a control device of an image forming apparatus according to an embodiment of the present invention.
The image forming apparatus according to the present embodiment includes a double-sided reversing mechanism, and in order to print a double-sided original, after the first side of the double-sided original is printed on the first side of the paper, the double-sided reversing mechanism reverses the paper. And a double-sided printing function (mechanism) for re-feeding the paper and printing the second side of the double-sided original on the second side. More specifically, the image forming apparatus according to the present embodiment has a double-sided printing function (mechanism) based on a so-called interleaf operation in which a printing process for the next sheet is performed while the sheet is reversed. Have.

In FIG. 1, a control device 10 of the image forming apparatus includes a document determination unit 11, a storage number determination unit 12, a print control unit 13, a conveyance control unit 14, and a CPU (Central Processing Unit) 15, a RAM (Random Access Memory). ) 16, a ROM (Read Only Memory) 17, an input unit 18, an output unit 19, a storage unit 20, and the like.
The document discrimination unit 11, the accommodation number discrimination unit 12, the print control unit 13, and the conveyance control unit 14 are realized as a function realization unit of the CPU 15 by a program stored in the ROM 17.
Here, the document discriminating means 11 determines whether a single-sided document with an image only on one side (first side) or a double-sided document with an image on both sides (first side and second side). The determination is made based on whether or not a document is registered in the queue. In addition, the number-of-accepting number determination unit 12 includes the number of sheets that can be stored in the reversing path (double-sided path) stored in the storage unit among the sheets on which the double-sided document determined by the document determining unit 11 is printed, and a double-sided path counter. Based on the counted number of sheets accommodated in the duplex path, it is checked whether there is an empty space in the duplex path, and the number of sheets that can be accommodated on the duplex path at the time of the check is determined.
Since this determination is based on simple subtraction processing, it may be performed as part of double-sided original print control by the print control control means, for example.

Further, the print control unit 13 performs control for executing printing of the first side of a single-sided document and printing of the first side of a double-sided document based on the determination result of the accommodation number determination unit 12 based on the determination result of the document determination unit 11. I do.
Based on the determination result of the document determination unit 11, the transport control unit 14 determines whether the paper on which the first surface of the document is printed is discharged as it is or transported to a double-sided path, and the accommodation number determination unit 12. On the basis of the determination result, the double-side reversing mechanism 22 is controlled to be actually transported to the double-sided path.

The RAM 16 provides a temporary storage area for data and programs as a work area for the CPU 15, and the ROM 17 provides a program storage area for operating the CPU 15.
The input unit 18 includes a well-known input unit such as a keyboard or a touch panel, for example, and performs necessary instructions or setting of the control device 10.
The output unit 19 includes, for example, a liquid crystal display (LCD) or the like, and confirms an input result or setting contents, or displays a paper processing state.
The storage unit 20 provides, for example, an area in which data such as a sheet structure, the number of copies, or the number of sheets per copy described later is registered as a queue (hereinafter simply referred to as queue registration).

The double-sided path is a path for reversing the sheet, which is arranged in the sheet conveyance path. The double-side reversing mechanism 22 is a well-known mechanism as disclosed in, for example, Japanese Patent No. 4065101, Japanese Patent Laid-Open No. 2000-16663, and the like.
The double-sided printing process by the interleaf operation in the image forming apparatus will be specifically described below.

2 and 3 are explanatory diagrams showing an outline of double-sided printing processing by an interleaf operation in the image forming apparatus of FIG.
Specifically, FIG. 2 shows a print output operation of a single-side original / double-side original mixed original bundle in double-sided printing by an interleaf operation for printing four originals and two originals according to the present invention. FIG. The symbols a, b, and c are the same as those shown in FIG.

As described with reference to FIG. 11, here, it is assumed that a document bundle (one set or one set) in which a single-sided document and a double-sided document are mixed is read by the image reading unit.
First, the first side, the third page (first copy), the fifth page (second copy: the original indicates the total number of copies) of the double-sided document, and the first side of the seventh page are continuously 1 to 4 Printing is performed on the first side of the first sheet (see (2) to (5)). Next, the second side of the first double-sided document is printed on the second side of the first sheet (see (6)). Next, the first side of the second sheet, which is a single-sided original, is printed on the first side of the fifth sheet (see (7)).

Hereinafter, the second side of the third original, the first side of the fourth original, the second side of the fifth original (the second part of the first original), the sixth side The first side of the original (second copy of the second original), the second side of the seventh original (second copy of the third original), the eighth side (2 of the fourth original) Printing is performed in the order of the second side of the second copy (see (8) to (13)).
In the present embodiment, in order to print a total of 8 (4 sheets × 2 surfaces + 4 sheets × 1 surface = total 12 surfaces) documents, 14 steps are required ((1) to (14)).

FIG. 3 is a diagram showing a print output operation of a single-side original / double-side original mixed document when duplex printing is performed on a set of four sheets according to another embodiment of the present invention in a two-part interleaf operation.
As in the case shown in FIG. 12 described above, it is assumed that only the second sheet of a set of four originals is a single-sided original and the rest is a double-sided original.
First of all, the first to fourth sheets of the first, third, fourth, fifth (total number of sheets: actually the same as the first) originals are double-sided. Print on the first side of the paper (see (1) to (5)). Next, the second side of the first document is printed on the second side of the first sheet (see (6)). Next, the first side of the second original, which is a single-sided original, is printed on the first side of the fifth sheet (see (7)).

  Next, the fifth sheet on which the first side of the single-sided original is printed is discharged to the discharge tray, and the first side of the seventh original, which is a double-sided original, is used as the first of the sixth sheet. Printing on the first side (see (8)), the second side of the third document is printed on the second side of the second sheet (see (9)). Similarly, the first side of the eighth original, which is a double-sided original, is printed on the first side of the seventh sheet (see (10)), and the second side of the fourth original is printed on the third side. Print on the second side of the paper (see (11)). After that, the second side of the fifth document is the second side of the fourth sheet, the first side of the sixth page is the first side of the eighth sheet, and the first side of the seventh sheet is The second side is printed on the second side of the sixth sheet and the second side of the eighth original is printed on the second side of the seventh sheet in that order.

  In the present embodiment, a total of 8 (6 sheets × 2 surfaces + 2 sheets × 1 surface = total 14 surfaces) manuscripts are printed in 16 steps ((1) to (16)).

FIG. 4 is a flowchart showing the entire processing procedure of the interleaf operation duplex printing process executed by the control device in FIG.
That is, this flowchart (algorithm) is executed when the computer (CPU 15, RAM 16, ROM 17) of the control apparatus 10 executes a computer-readable program.

After starting the job, the control device 10 first performs initial setting (S101: refer to the flowchart of FIG. 5 for the initial setting procedure). Next, the control device 10 checks whether a document is registered in the duplex queue (whether there is a duplex document) as document discrimination means (S102). (S103: Refer to the flowchart of FIG. 7 for the procedure of single-sided output processing).
If there is a double-sided document, the control device 10 performs a process of printing the first surface (S104: refer to the flowchart of FIG. 8 for the procedure of the printing process), and then the accommodation number determination means 12 of the control device 10 Based on the number of sheets that can be accommodated in the reversing path stored in the storage means and the number of sheets accommodated in the sheet reversing path counted by the duplex path counter, it is checked whether there is a vacancy in the duplex path (S105). ). If there is a vacancy in the duplex path, the control device 10 checks whether there is a duplex document to be printed next (S106), and if there is a vacancy, returns to the process of printing the first side (S104). That is, the control device 10 performs a process of printing the first side as long as there is an empty duplex path and there is a duplex document.

  If there is no space in the duplex path, or there is space in the duplex path but there is no duplex document to be printed next, the control device 10 executes an output process (S107: the procedure of the output process is the flowchart of FIG. 9). reference). If the output process has been completed and the job is in an end state (S108, YES), the control device 10 ends the job. If the job is still in the middle of the job (S108, NO), the process returns to step S105, and the double-side pass Is checked (S105). That is, the process waits for the duplex path to be empty, and if it is empty, the process proceeds to the output process (S107).

FIG. 5 is a flowchart showing the procedure of the initial setting process executed in FIG.
First, the control device 10 sets the number of copies in the output job (S201) and the number of copies per copy (referred to as the number of copies) (S202). In this algorithm example, a queue in which a paper structure, which will be described later, constituting the copy is registered is prepared for each copy. That is, since there is one queue per copy, the control device 10 checks whether or not all sheets per copy are registered in one queue (referred to as all paper queue) (S203).

  If it is determined in step S203 that the value of the all cue counter is not smaller than the number of copies (S203, NO), that is, if it is determined that one copy of paper has been registered in one full paper queue, the control device 10 Next, the copy counter is incremented (S204). Here, the control device 10 compares the copy counter with the initially set copy number information to check whether all the paper queues for all the copies of the current job have been prepared (S205).

  If the value of the number of copies counter is less than the number of copies information, that is, if all the number of all-sheet queues are not yet prepared (S205, YES), the control device 10 newly sets the queue (all-sheet queue, double-sided queue). Prepare (S206) and return to step S203. On the other hand, if the number of copies counter is not less than the number of copies information (S205, NO), the control device 10 ends the initial setting, assuming that all the sheets of paper have been registered.

FIG. 6 is a diagram showing a sheet structure of each sheet used in the flowchart of FIG.
The paper structure that stores the paper information includes at least a printing status indicating a printing state (including paper discharge) and a one-sided status indicating one-sided or both-sided.

  Returning to the flowchart of FIG. 5 again, when the value of the all queue counter is smaller than the number of copies information in step S203 (S203, NO), the control device 10 registers the sheet structure in the all sheet queue. Prepare the paper structure in the memory of the storage unit 20 (initialize the paper structure) (S207), and execute the setting (entry set) of the paper structure member that sets the respective data for each member of the structure (S208).

  Next, the control device 10 registers the created paper structure in the all-paper queue (S209), and increments the all-paper queue counter (S210). At this time, if the registered paper structure is a double-sided original (S211, YES), the control device 10 registers in the double-sided queue (S212), increments the double-sided queue counter (S213), and step S203. Return to the process. If the original is not a double-sided original (S211, NO), the process returns to step S203 as it is, and the process is repeated until all the paper structures are set in the respective queues, that is, until NO is determined in step S203.

FIG. 7 is a flowchart showing the single-sided output processing procedure executed in S103 in FIG.
If all the originals are single-sided, this single-sided output subroutine is executed. In this algorithm, two queues are used for each queue: a next sheet pointer indicating the sheet structure to be fed from now on and a leading sheet pointer indicating the position of the leading sheet structure in the machine during printing processing. (S301).
Considering that this subroutine is called directly at the time of error recovery or the like, the control device 10 first aligns the next sheet pointer with the first sheet pointer, and then performs the next sheet printing (print) operation (S302) and the sheet discharge processing operation ( S303) is started in parallel.

In the next sheet printing, in order to indicate that printing is in progress, the control device 10 sets “first side” to the printing status that is a member of the sheet structure (S304). Since this algorithm example is premised on double-sided printing by a four-sheet interleaf operation, there is a possibility that a maximum of five sheets may exist simultaneously in the machine.
For this reason, for example, five print statuses are prepared for each paper structure so that it is possible to cope with a case where there are a plurality of jobs for one sheet printing, and all the copies are currently printed. The number of the print status to be used is determined by the counter information.

Next, when a sheet is fed, the control device 10 increments the next sheet pointer of the all sheet queue (S305), and determines whether or not the printing of all the sheets belonging to that section has been completed. Are checked (S306). If there is still paper (S306, YES), the process returns to the next paper printing process in step S302.
When printing to the end of the number of sheets registered in the all-paper queue is made, the control device 10 checks whether there is an unoutputted copy by comparing all counter values with the copy count information (S307). If the total counter is not smaller than the number of copies information (S307, NO), the control device 10 has set the paper feed end flag (S308) because all the copies (numbers) have been fed and printed. Wait for the operation to finish.

  In step 307, if the next part counter is less than the number of copies information (S307, YES), that is, there are still unoutput parts, the control device 10 changes the all-paper queue to the next part. (S309) The next sheet pointer is initialized (0 is entered) (S310), the next section counter is incremented (S311), and the process returns to step S302.

In the paper discharge operation, the control device 10 first checks whether or not the paper has been discharged (S303), and when the paper is discharged (S303, YES), the printing (print) status is set to “done”. The sheet is set (S312), and the all-paper queue top sheet pointer is incremented (S313).
Next, the control device 10 checks whether or not all the sheets in that section have been discharged by comparing the leading sheet pointer with the all sheet queue counter (S314), and the leading sheet pointer is smaller than the all sheet queue counter value. If there is an undischarged sheet (S314, YES), the process returns to step S303.

When the discharge is completed up to the end of the all-paper queue (S314, NO), the control device 10 checks whether there is still an unoutput “copy” by comparing all counter values with the number of copies (S315). ).
If the total counter value is less than the number of copies information (S315, YES), there is still an unoutput portion, so the control device 10 changes the all-paper queue to the next one (S316), and the leading paper pointer Is initialized (0 is entered) (S317), all counters are incremented (S318), and the process returns to step S303. If the total counter value is not smaller than the number of copies information (S315, NO), since the paper discharge operation has been completed for all the “copies”, the control device 10 sets the paper discharge end flag (S319). Synchronize with the paper feeding operation.

  Here, when both the paper feed operation and the paper discharge operation are completed (both end flags are set), the control device 10 sets a job end flag indicating that the job has ended (S320), and outputs on one side. The process ends.

FIG. 8 is a flowchart showing the procedure of the first surface process executed in S104 in FIG. If there is a double-sided document in the print job, this subroutine is executed.
First, the control device 10 determines whether or not there is error recovery (S401), and after error recovery (S401, YES), initializes the double-sided queue pointer (S402). If it is not after error recovery (S401, NO), there should be several documents that have already been output, and since it is only necessary to output from there, the control device 10 does not perform initialization.

The control device 10 performs the printing process with the paper pointed to by the next paper pointer as the head (S403). Here, since the target of the printing process is the first side of the double-sided document, the control device 10 increments the double-sided pass counter because it enters the double-sided pass after printing (S404).
Subsequently, the control device 10 sets the front / back status (printing status) to the second side (S405) to indicate that the next printing is the second side (S405), and the first side (image thereof) is paper. Is set on the first surface (S406).

At this time, since five statuses indicating the print status are prepared for each sheet structure, the control device 10 determines which status variable is to be used based on all the counter information. This is because, in the case of double-sided printing by four-sheet interleaf operation, there is a possibility that a maximum of five sheets (four sheets in a double-sided pass + one sheet currently being printed) may exist in the apparatus at the same time. This is to prevent duplication.
When printing of the first sheet is executed, the control device 10 updates (increments) the next sheet pointer to the next sheet (S407), and ends this process (first surface process).

FIG. 9 is a flowchart showing the procedure of the output process executed in S107 in FIG. This flowchart is a subroutine for performing a series of processing from printing processing to output of the second side of a double-sided document.
First, the control device 10 determines whether or not there is error recovery (S501), and after error recovery (S501, YES), initializes the pointer of all paper queues, that is, sets the next paper pointer of all paper queues to the head of all paper queues. Processing for matching with the pointer is performed (S502). If it is not after error recovery (S501, NO), there should be several documents that have already been output, and since it is only necessary to output from there, the control device 10 does not perform initialization.
Next, the control device 10 starts the next paper printing (S503) and the paper discharge processing operation (S504) in parallel.

In the next sheet printing process, the control device 10 sets “second side” to the printing status that is a member of the sheet structure to indicate that printing is in progress (S505). Since this algorithm example is premised on four-sheet interleaf operation double-sided printing, there may be a maximum of five sheets in the machine at the same time.
For this reason, for example, five print statuses are prepared for each paper structure so that it is possible to deal with a case where a plurality of jobs for one sheet are printed. The number of the print status to be used is determined by the counter information.

  Next, when a sheet is fed, the control device 10 increments the next sheet pointer of the all sheet queue (S506), and compares the next sheet pointer with the all sheet queue counter to determine whether or not all the sheets have been printed. This is checked (S507). If there is still paper remaining, that is, if the next paper pointer is smaller than the all paper queue counter value (S507, YES), the control device 10 waits for the completion of paper discharge (S508, YES), and then performs the next paper printing task. To return to the main job processing.

When printing has been completed up to the end of the all-paper queue (S507, NO), the control device 10 checks whether there is still an unoutput “copy” by comparing the next counter and the copy number information (S509). If the next copy counter value is not smaller than the “number of copies” of the number of copies information (S509, NO), the sheet feeding / printing has been completed for all the “copies”, so that the control device 10 A flag is set (S510), and the completion of the paper discharge operation is awaited.
If the total counter value is less than the “number of copies” of the number of copies information (S509, YES), that is, if there is still a “copy” that has not been output (S509, YES), the control device 10 sets the next paper queue to the next one. (S511), the next paper pointer is initialized (0 is inserted) (S512), and the above-mentioned "part" is fed, so that all counters are incremented (S513), and the completion of paper discharge is awaited. (S514, Yes) The next sheet printing task is terminated.

On the other hand, in the paper discharge process, the control device 10 first determines whether or not the paper is discharged (S504), and if it is discharged (S504, YES), sets the print status to “completed” (S504). In S515, the all-paper queue top sheet pointer is incremented (S516).
Here, the control device 10 checks the single-sided / double-sided status of the paper (S517), and if it is a double-sided original (S517, YES), it decrements the double-sided pass counter (S518) and increments the leading paper pointer of the double-sided queue. (S519). If the original is not a double-sided original (S517, NO), the steps S518 and S519 are skipped.

Next, the control device 10 checks whether or not all sheets of the “part” have been discharged by comparing the leading sheet pointer with the all sheet queue counter value (S520), and the leading sheet pointer is the all sheet queue counter value. If there are fewer, that is, there are still undischarged sheets (S520, YES), the process is terminated.
If the leading sheet pointer is not less than the all sheet queue counter value, that is, the sheet has been discharged to the end of the all sheet queue (S520, NO), the control device 10 determines whether there is still an unoutput “part”. And the number of copies information are compared (S521). If the total counter value is less than the number of copies in the above-mentioned copy number information (S521, YES), there is still an unoutputted portion, so the control device 10 changes the all-paper queue to the next “copy” (S522). The control device 10 initializes the leading paper pointer (inserts 0) (S523), increments all counters (S524), and ends the processing.
If the total counter value is not smaller than the number of copies in the above-mentioned copy number information (S521, NO), the discharge operation has been completed for all the “copies”, so the control device 10 sets the discharge end flag ( S525), synchronization with the next sheet printing process is performed.

  When both the paper feed operation and the paper discharge operation are completed (both end flags are set), the control device 10 sets a job end flag indicating that the job has ended (S526), and ends this output processing. To do.

  In an embodiment of the present invention, when an image forming apparatus that performs double-sided printing by n-sheet interleaf operation is printed out on a sheet bundle containing both single-sided originals and double-sided originals, only double-sided originals are printed on n sheets. The first side is continuously printed on paper first. As a result, it is possible to reduce a double-sided pass-through loss during double-sided document printing that occurs when printing is performed in the order of output, thereby improving printing productivity.

  In addition, since the idle time of the photoconductor and the developing drum constituting the image forming apparatus is shortened, the scattering of toner into the apparatus can be suppressed. As a result, the occurrence of abnormal images such as black spots and the life deterioration of the developer can be suppressed. Furthermore, since the operation time is shortened, an effect of reducing power consumption can be expected.

  DESCRIPTION OF SYMBOLS 10 ... Control apparatus, 11 ... Document discriminating means, 12 ... Accommodating number discriminating means, 13 ... Print control means, 14 ... Conveyance control means, 15 ... CPU, 16 ... RAM, 17... ROM, 18... Input unit, 19... Output unit, 20.

JP 2000-16663 A

Claims (8)

There are two-sided printing that prints a double-sided document with a first side and a second side on both the first and second sides of the paper, and one-sided printing that prints a single-sided document with only the first side on the first side of the paper. An image forming apparatus that prints a mixed number of originals,
Printing means;
A sheet reversing path for conveying the printing unit by reversing the paper first side of the duplex document has been printed,
As long as the paper can be accommodated in the paper reversing path, the first side of the plurality of double-sided originals is continuously printed on the first side of the paper, and then the two sides of the paper on the second side of the plurality of papers. Print control means for controlling to perform the process of printing the second side of the original and the process of printing the first side of the one-sided original on the first side of the paper in the arrangement order of the originals;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
Storage means for storing information on the number of sheets that can be accommodated in the sheet reversing path;
The printing control means sets the first side of the double-sided document on the first sheet based on the number of sheets that can be stored in the sheet reversing path stored in the storage section and the number of sheets that are stored in the sheet reversing path. An image forming apparatus that performs a process of printing on one side. The image forming apparatus according to claim 1 or 2,
An image forming apparatus comprising a document discrimination unit for discriminating between a single-sided document and a double-sided document. The image forming apparatus according to claim 3.
The printed paper the first surface, the document discrimination means, based on the number of sheets of the as can accommodate the number of sheets stored in the sheet inverting path in the storage unit is accommodated in the sheet reversing path, the paper An image forming apparatus comprising: a conveyance control unit that performs conveyance control on a reversing path or a paper discharge unit. There are two-sided printing that prints a double-sided document with a first side and a second side on both the first and second sides of the paper, and one-sided printing that prints a single-sided document with only the first side on the first side of the paper. Print a mixed number of documents,
Printing means;
A printing control method for controlling printing of a document in an image forming apparatus having a sheet reversing path for reversing a sheet on which a first surface of the double-sided document is printed and transporting the sheet to the printing unit ,
As long as the paper can be accommodated in the paper reversing path, the first side of the plurality of double-sided originals is continuously printed on the first side of the paper, and then the two sides of the paper on the second side of the plurality of papers. And a print control step for controlling the process for printing the second side of the original and the process for printing the first side of the single-sided original on the first side of the paper in the arrangement order of the originals. Print control method. In the printing control method according to claim 5,
In the printing control step, the first side of the double-sided document is printed on the first side of the sheet based on the number of sheets that can be stored in the sheet reversing path stored in the storage unit and the number of sheets that are stored in the sheet reversing path. A printing control method characterized by being a step of performing a process of printing on a surface. In the printing control method according to claim 5 or 6,
A printing control method comprising a document discrimination step for discriminating between a single-sided document and a double-sided document. In the printing control method according to claim 7,
The printed paper the first surface, the document discrimination step, on the basis of the number of sheets of the as can accommodate the number of sheets stored in the sheet inverting path in the storage unit is accommodated in the sheet reversing path, sheet reversal A printing control method comprising a conveyance control step of performing conveyance control on a path or a paper discharge unit.

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