JP2019123155A - Printer - Google Patents

Abstract

To provide a printer in which a time until completion of printing is shortened when a conveyance error occurs on a circulation path.SOLUTION: The printer comprises: a paper feeding part 2 which feeds a sheet to a paper feeding path; a printing part 3 which performs printing onto the sheet conveyed from the paer feeding path to a printing path; changeover means which performs changeover between a circulation path which reverses front and back of the sheet fed by printing means, and circulates the sheet to the printing path again, and a paper discharge path which discharges the printed sheet to a paper discharge table; an error determination part 61 which determines in which of the paper feeding path, the printing path, the circulation path and the paper discharge path a conveyance error occurs when the sheet conveyance error occurs when the printing part 3 performs two-sided printing; and a printing control part 62 which causes the printing part 3 to continue single-sided printing by use of the paper feeding path, the printing path and the paper discharge path until a printing job is completed when it is determined that a conveyance error occurs in the circulation path, and discharges the single-sided printed sheet to the discharge table.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a printing apparatus that shortens the time until print completion by continuing single-sided printing until the end of a print job when a transport error occurs on a circulation path.

  The line type printing apparatus ejects ink from an ink jet head on a sheet transported on a printing path by transport means such as a transport roller to print an image, characters and the like.

  In the case of single-sided printing, ink is discharged from the ink jet head onto the surface of the sheet fed from the sheet feeding table and transported on the printing path, and then the sheet is discharged onto the sheet discharging table.

  In the case of double-sided printing, after printing the surface in the same manner, the sheet is circulated and conveyed on the circulation path, and the reversed sheet is conveyed on the printing path again. Then, after the ink is ejected from the ink jet head and printed on the back surface of the sheet conveyed on the printing path, the sheet is discharged to the sheet discharge tray.

  In a line-type printing apparatus, a conveyance error may occur due to a paper jam or the like in the conveyance means. However, depending on the position where the transport error occurs, it may be possible to continue the transport by switching the transport path.

  Patent Document 1 has a double-sided printing function, and when a double-sided printing unit error (conveyance error) occurs, if there is a toner image on the intermediate transfer belt, the toner image is printed on one side of the sheet and discharged. Technology related to an electrophotographic image forming apparatus is disclosed.

Unexamined-Japanese-Patent No. 2010-30235

  However, in the technique of Patent Document 1, when the toner image is present on the intermediate transfer belt, the toner image is printed on one side of the sheet and discharged, but the printing is not continued thereafter. That is, although printing is performed on a sheet being printed, a new toner image is not generated on the intermediate transfer belt to continue printing.

  Therefore, when a double-sided printing unit error occurs, since the remaining double-sided printing of the print job is resumed after the error is canceled, it takes a considerable amount of time to complete all the printing. For example, if a user starts double-sided printing on several hundred sheets and then a double-sided printing unit error occurs on several sheets, single-sided printing is performed on the sheet on which the toner image is generated, but the remaining sheets are It will be in a standby state. Therefore, it takes a considerable amount of time to complete hundreds of double-sided printing.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a printing apparatus capable of shortening the time until printing completion by continuing single-sided printing until the end of a print job when a transport error occurs on a circulation path. With the goal.

In order to achieve the above object, a first feature of the printing apparatus according to the present invention is
A sheet feeding unit that feeds sheets placed on a sheet feeding table to a sheet feeding path one by one;
A printing unit that prints based on a print job on a sheet conveyed from the sheet feeding path to the printing path;
Switching means for reversing the front and back of the sheet printed by the printing means and switching between the circulation path circulating to the printing path and the paper discharge path for discharging the printed sheet to the paper discharge tray again ,
Any of the paper feed path, the print path, the circulation path, and the paper discharge path, when a conveyance error of the sheet occurs while the printing unit is printing based on the print job including double-sided printing Error determination means for determining whether the transport error has occurred at
When it is determined by the error determination unit that a transport error has occurred in the circulation route, the single-sided printing unit uses the sheet feed route, the print route, and the sheet discharge route until the print job ends. And printing control means for continuing the printing and discharging the single-sided printed sheet to the sheet discharge tray.

  According to the first aspect of the printing apparatus according to the present invention, when a transport error occurs on the circulation path, the time until printing completion can be shortened by continuing single-sided printing until the end of the print job .

FIG. 1 is a schematic configuration diagram of a printing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a control block diagram of the printing apparatus shown in FIG. FIG. 6 is a diagram showing a printing order on a designated paper discharge destination and printing surface, and a printing order and paper discharge destination at the time of reprinting, in the printing apparatus according to the first embodiment of the present invention. FIG. 6 is a diagram showing a printing order on a designated paper discharge destination and printing surface, and a printing order and paper discharge destination at the time of reprinting, in the printing apparatus according to the first embodiment of the present invention. FIG. 6 is a view showing an image of a placement order, a number of unprinted sheets, and a placement order of a single-sided printed sheet notified by a notification unit included in the printing apparatus according to the first embodiment of the present invention. It is the flowchart which showed the processing contents of the printer which relates to the form 1 of execution of this invention. It is the flowchart which showed the processing contents of the printer which relates to the form 1 of execution of this invention. It is the flowchart which showed the processing contents of the printer which relates to the form 2 of execution of this invention.

  Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. The same or equivalent parts or components are denoted by the same or equivalent reference numerals throughout the drawings.

  The embodiment shown below exemplifies an apparatus and the like for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, arrangement and the like of each component. It does not specify the following. Various changes can be added to the technical idea of the present invention within the scope of the claims.

Embodiment 1 of the Present Invention
FIG. 1 is a schematic block diagram of a printing apparatus according to a first embodiment of the present invention. FIG. 2 is a control block diagram of the printing apparatus shown in FIG. In the following description, the direction orthogonal to the paper surface of FIG. 1 is referred to as the front-rear direction, and the front direction of the paper surface is referred to as the front. Further, the top, bottom, left, and right of the sheet of FIG. 1 are referred to as the top, bottom, left, and right directions.

  A path indicated by a thick line in FIG. 1 is a transport path through which a sheet, which is a print medium, is transported. Among the transport paths, the path shown by a solid line is a print path RP, the path shown by an alternate long and short dash line is a circulating path RC, the path shown by a dashed line is a first sheet discharge path RD1 and a second sheet discharge path RD2, and the path is an alternate path They are an external sheet feeding path RS1 and an internal sheet feeding path RS2. In the following description, upstream and downstream mean upstream and downstream in the transport path.

  As shown in FIGS. 1 and 2, the printing apparatus 1 according to the first embodiment includes a sheet feeding unit 2, a printing unit 3, a circulating conveyance unit 4, a sheet discharging unit 5, and a control unit 6. And a housing 7 for storing or holding each part.

  The sheet feeding unit 2 feeds an unprinted sheet P to the printing unit 3. Further, the paper feed unit 2 refeeds the paper P after the front surface printing to the printing unit 3 at the time of double-sided printing. The sheet feeding unit 2 is disposed on the most upstream side of the conveyance path. The sheet feeding unit 2 includes an external sheet feeding table 11, an external sheet feeding roller 12, internal sheet feeding tables 13A and 13B, internal sheet feeding rollers 14A and 14B, and motors (not shown) for driving the respective conveyance rollers. And inner sheet feed sensors 18A to 18C, a vertical conveyance roller 19, and a vertical conveyance sensor 21.

  The external sheet feeding table 11 is a stack of sheets P used for printing. The external sheet feeding table 11 is partially exposed to the outside of the housing 7 and installed.

  The external sheet feeding roller 12 picks up the sheets P stacked on the external sheet feeding table 11 one by one, and conveys the sheet P toward the registration roller 31 of the printing unit 3 described later along the external sheet feeding path RS1. .

  The internal paper feed trays 13A and 13B are loaded with sheets P used for printing. The internal paper feed trays 13A and 13B are disposed inside the housing 7.

  The internal feed rollers 14A and 14B take out the sheets P stacked on the internal feed trays 13A and 13B one by one.

  The internal sheet feeding and conveying rollers 16A and 16B convey the sheet P taken out from the internal sheet feeding trays 13A and 13B by the internal sheet feeding rollers 14A and 14B to the internal sheet feeding and conveying roller 16C. The internal paper feed conveyance roller 16C conveys the sheet P conveyed by the internal paper feed conveyance roller 16A or the internal paper feed conveyance roller 16B to the vertical conveyance roller 19. The internal sheet feeding / conveying roller 16C is disposed downstream of a junction of a portion of the internal sheet feeding path RS2 extending from the internal sheet feeding roller 14A and a portion extending from the internal sheet feeding roller 14B.

  The internal sheet feeding sensors 18A to 18C detect the sheet P taken out from the internal sheet feeding trays 13A and 13B and conveyed to the vertical conveyance roller 19. The internal sheet feeding sensors 18A to 18C are disposed at predetermined positions near the downstream side of the internal sheet feeding conveyance rollers 16A to 16C, respectively.

  The vertical conveyance roller 19 conveys the sheet P conveyed from the internal paper feed conveyance roller 16C along the internal paper feed path RS2 to the registration roller 31 of the printing unit 3 described later. Further, the vertical conveyance roller 19 conveys the sheet P after surface printing, which has been circularly conveyed along the circulation route RC during double-sided printing, to the registration roller 31. The vertical conveyance roller 19 is disposed along the internal sheet feeding path RS2 on the downstream side of the junction point of the circulation path RC with the internal sheet feeding path RS2.

  The vertical conveyance sensor 21 detects the sheet P conveyed from the vertical conveyance roller 19 to the registration roller 31. The vertical conveyance sensor 21 is disposed at a predetermined position near the downstream side of the vertical conveyance roller 19.

  The printing unit 3 prints an image on the sheet P while conveying the sheet P. The printing unit 3 is disposed downstream of the sheet feeding unit 2. The printing unit 3 includes a registration roller 31, a registration sensor 32, a belt conveyance unit 33, a line sensor 34, a head unit 35, and motors (not shown) that drive the conveyance rollers.

  The registration roller 31 temporarily stops the sheet P conveyed by the external sheet feeding roller 12 or the vertical conveyance roller 19 to correct a skew, and then conveys the sheet P to the belt conveyance unit 33. The registration roller 31 is disposed on the printing path RP on the upstream side of the printing unit 3.

  The registration sensor 32 detects the sheet P conveyed from the external sheet feeding roller 12 or the vertical conveyance roller 19 to the registration roller 31. The registration sensor 32 is disposed at a predetermined position near the upstream side of the registration roller 31.

  A belt conveyance unit 33 is disposed downstream of the registration roller 31. The belt conveyance unit 33 adsorbs and holds the sheet P conveyed by the registration roller 31 on an annular belt and conveys the sheet P. The belt is stretched around the roller, and the transport belt is endlessly moved by the rotation of the roller by the rotational drive of the motor. An encoder is attached to the motor, and the number of revolutions of the motor can be detected.

  The line sensor 34 is a sensor in which CCDs, which are light receiving elements, are arranged in a line, and detects dirt on the sheet P conveyed by the belt conveyance unit 33. The line sensor 34 is disposed at a predetermined position near the upstream side of the head unit 35.

  The head unit 35 has four line-type inkjet heads (not shown) in which a plurality of nozzles are arranged along a direction (front-rear direction) orthogonal to the conveyance direction of the sheet P. The head unit 35 is disposed above the belt conveyance unit 33. The head unit 35 prints an image by discharging ink (for example, cyan, black, magenta, yellow) from the nozzles of the ink jet head onto the sheet P conveyed by the belt conveyance unit 33.

  The circulation conveyance unit 4 conveys the sheet P after surface printing along the circulation route RC at the time of double-sided printing and delivers the sheet P to the vertical conveyance roller 19. The circulation conveyance unit 4 includes a plurality of pairs of intermediate conveyance rollers 41, a reverse inlet sensor 42, a reverse roller 43, a switchback sensor 44, a plurality of pairs of horizontal conveyance rollers 45, a double-sided conveyance inlet sensor 46, and A pair of upward conveyance rollers 47, a reverse conveyance sensor 48, a double-sided conveyance outlet sensor 49, and motors (not shown) for driving the respective conveyance rollers are provided.

  The intermediate conveyance roller 41 conveys the sheet P after surface printing to the reversing roller 43 at the time of double-sided printing. A plurality of pairs of intermediate conveyance rollers 41 are disposed along a circulation path RC between the printing unit 3 and the reversing roller 43.

  The reverse entrance sensor 42 and the reverse conveyance sensor 48 detect the sheet P conveyed by the intermediate conveyance roller 41. The reverse entrance sensor 42 and the reverse conveyance sensor 48 are respectively disposed at predetermined positions near the downstream side of the intermediate conveyance roller 41.

  The reversing roller 43 switches back the sheet P conveyed by the intermediate conveyance roller 41 and conveys the sheet P to the horizontal conveyance roller 45. The reversing roller 43 is disposed downstream of the intermediate conveyance roller 41 along the circulation path RC.

  The switchback sensor 44 detects the sheet P switched back by the reversing roller 43.

  The horizontal conveyance roller 45 conveys the sheet P switched back by the reversing roller 43 to the upward conveyance roller 47. A plurality of pairs of horizontal conveyance rollers 45 are disposed along the upstream portion of the circulation route RC between the reversing roller 43 and the junction of the circulation route RC with the internal paper feed route RS2.

  The double-sided conveyance inlet sensor 46 detects the sheet P conveyed by the horizontal conveyance roller 45.

  The plurality of pairs of upward conveyance rollers 47 convey the sheet P conveyed by the horizontal conveyance roller 45 to the vertical conveyance roller 19. A plurality of pairs of upward conveying rollers 47 are disposed along the downstream portion of the circulation path RC between the reversing roller 43 and the junction of the circulation path RC with the internal sheet feeding path RS2.

  The double-sided conveyance outlet sensor 49 detects the sheet P conveyed from the circulation conveyance unit 4 to the vertical conveyance roller 19. The double-sided conveyance exit sensor 49 is disposed at a predetermined position near the downstream side of the most upstream conveyance roller 47.

  The discharge unit 5 discharges the printed sheet P. The paper discharge unit 5 includes a first switching unit 51, an upper surface conveyance entrance sensor 52, a second switching unit 53, a rising conveyance sensor 54, a plurality of pairs of first paper discharge rollers 55, and a paper discharge sensor 56. A plurality of pairs of second discharge rollers 57, a face-up discharge tray 58, a face-down discharge tray 59, and motors (not shown) for driving the respective conveyance rollers are provided.

  The first switching unit 51 switches the conveyance path of the sheet P between the first sheet discharge path RD1 and the circulation path RC. The first sheet discharge path RD1 is a path extending from the downstream end of the printing path RP toward a post-processing device (not shown) disposed on the right side of the printing apparatus 1. The first switching unit 51 is disposed at a branch point between the first sheet discharge path RD1 and the circulation path RC.

  The top transport entrance sensor 52 detects the sheet P whose transport path has been switched to the first sheet discharge path RD1 by the first switching unit 51.

  The second switching unit 53 switches the conveyance path of the sheet P between the first sheet discharge path RD1 and the second sheet discharge path RD2. The second sheet discharge path RD2 is a path that branches from the first sheet discharge path RD1 toward the face-down sheet discharge tray 59 on the downstream side of the branch point between the first sheet discharge path RD1 and the circulation path RC. The second switching unit 53 is disposed at a branch point where the second sheet discharge path RD2 branches from the first sheet discharge path RD1.

  The first sheet discharge roller 55 discharges the sheet P conveyed from the printing unit 3 to the face-up sheet discharge table 58. The plurality of pairs of first sheet discharge rollers 55 are disposed along the first sheet discharge path RD1.

  The face-up sheet discharge tray 58 is configured to load the sheets P discharged by the first sheet discharge roller 55 with the printing surface facing upward. At the time of double-sided printing, stacking is performed so that the last printed side faces up. The face-up sheet discharge tray 58 is disposed at the downstream end of the first sheet discharge path RD1.

  The second sheet discharge roller 57 discharges the sheet P conveyed from the printing unit 3 to the face-down sheet discharge tray 59. The plurality of pairs of second sheet discharge rollers 57 are disposed along the second sheet discharge path RD2.

  The rising conveyance sensor 54 detects the sheet P conveyed by the second sheet discharge roller 57.

  The sheet discharge sensor 56 detects the sheet P discharged to the face-down sheet discharge tray 59. The sheet discharge sensor 56 is disposed at a predetermined position near the upstream side of the most downstream second sheet discharge roller 57.

  The face-down sheet discharge tray 59 is configured to load the sheets P discharged by the second sheet discharge roller 57 with the printing surface facing downward. At the time of double-sided printing, stacking is performed so that the last printed side faces downward. The face-down delivery tray 59 is disposed at the downstream end of the second delivery path RD2.

  The above-described external sheet feeding roller 12, internal sheet feeding rollers 14A and 14B, internal sheet feeding and conveying rollers 16A to 16C, vertical conveyance roller 19, registration roller 31, intermediate conveyance roller 41, reversing roller 43, horizontal conveyance roller 45, The rising conveyance roller 47, the first sheet discharge roller 55, and the second sheet discharge roller 57 are collectively referred to as a conveyance roller.

  Also, internal sheet feeding sensors 18A to 18C, vertical conveyance rollers 19, vertical conveyance sensors 21, registration sensors 32, line sensors 34, reverse entrance sensors 42, switchback sensors 44, double-sided conveyance entrance sensor 46, reverse conveyance sensors 48, The double-sided conveyance outlet sensor 49 is generically called a paper sensor.

  The control unit 6 controls the operation of each unit of the printing apparatus 1. The control unit 6 includes a CPU, a RAM, a ROM, a hard disk, and the like.

  The control unit 6 functions as an error determination unit 61, a print control unit 62, and a notification unit 63 by executing a control program.

  The error determination unit 61 determines, based on the detection result of the sheet sensor, whether a sheet conveyance error has occurred. Specifically, based on the transport speed of the transport roller and the belt, the sheet sensor adjacent to the downstream side on the transport path does not detect the sheet within a predetermined time from the time when the upstream sheet sensor detects the sheet. If so, it is determined that a transport error has occurred.

  When a transport error occurs, the error determination unit 61 determines that the transport error includes the external sheet feed path RS1, the internal sheet feed path RS2, the print path RP, the circulation path RC, the first sheet discharge path RD1, and the second sheet discharge. It is determined in which of the routes RD2 the error has occurred.

  Here, it is assumed that a transport error has occurred in circulation path RC among external sheet feed path RS1, internal sheet feed path RS2, print path RP, circulation path RC, first sheet discharge path RD1, and second sheet discharge path RD2. Also, it is possible to feed from the paper feed tray, print on one side, and discharge the sheet to the paper discharge tray.

  Therefore, when the print control unit 62 determines that the transport error has occurred in the circulation route RC by the error determination unit 61, the transport route other than the circulation route RC, that is, the external paper feed route RS1 until the print job ends. Using the internal sheet feed path RS2, the circulation path RC, the first sheet discharge path RD1, and the second sheet discharge path RD2, the single-sided printing is continued to the printing unit 3 and the sheet P printed on one side is face up discharged The sheet is discharged to the tray 58 or the face down discharge tray 59.

  The notification unit 63 uses the single-sided printed sheet P to be placed on the sheet feeding table based on the discharge destination designation information and the printing surface information included in the print job for double-sided printing and the page number requiring reprinting. Notify the placement order, the number of unprinted sheets, and the placement order. For example, a reprint message “Please place the print side of the single-sided printed sheet downward and put three unprinted sheets on it” is displayed on the operation panel 8. Here, the delivery destination specification information is information for specifying either the face-up delivery tray 58 or the face-down delivery tray 59. The printing surface information is information for specifying the orientation of the printing surface, and "upward" or "downward" is specified. The notification may be displayed on the operation panel 8 or may be displayed on a PC connected via a network (not shown).

  The user places the single-sided printed sheet P and the unprinted sheet P on the sheet feeding tray based on the notification.

  When print control unit 62 requests reprint from operation panel 8, single-sided printed sheet P and unprinted sheet are printed based on the page number that needs to be reprinted, discharge destination designation information, and print side information. The printing order and the discharge destination are determined for P, and printing (reprinting) is performed based on the determined printing order and the discharge destination.

  FIGS. 3A and 3B are diagrams showing the printing order on the designated paper discharge destination and printing surface, and the printing order and paper discharge destination at the time of reprinting. FIG. 4 is a view showing an image of the placement order of the single-sided printed sheets P notified by the notification unit 63, the number of unprinted sheets P, and the placement order.

  In the example of FIG. 3A (a), the printing order and the discharge destination at the time of reprinting when “face-up paper discharge tray” is specified as the discharge destination and “upward” is specified as the printing surface Is shown. Similarly, in the example of FIG. 3A (b), when "face-up paper discharge tray" is designated as the discharge destination and "downward" is designated as the printing surface, in the example of FIG. 3B (c) When "Face-down delivery tray" is specified as the delivery destination and "upward" is specified as the printing surface, in the example of FIG. 3B (d), "Face-down delivery tray as the delivery destination" "Is designated and" down "is designated as the printing surface, the printing order and the discharge destination at the time of reprinting are shown. FIGS. 4A to 4D correspond to FIGS. 3A to 3D, respectively.

  As shown in FIG. 3A (a), when “face-up paper discharge tray” is specified as the discharge destination and “upward” is specified as the printing surface, printing is performed from the last page, so the printing order of the 10th page Becomes "1". That is, printing is performed sequentially from the 10th page.

  Here, it is assumed that a conveyance error occurs when double-sided printing from page 10 to page 8 is completed, and single-sided printing on sheet P from page 7 to page 5 is completed. There is. At this time, since the sheets P of the seventh to fifth pages remain in the circulation path RC, the user needs to remove the three sheets P.

  On the other hand, single-sided printing of the back side is performed on the fourth and first pages.

  Then, a message “Please place the printing side of the single-sided printed sheet downward and put three unprinted sheets on it” is displayed on the operation panel 8. As shown in FIG. 4A, the user places the single-sided printed sheets P1 to P4 on the sheet feeding table with the print side facing downward, and further, three unprinted sheets P5 on the sheet. Place the.

  When reprinting is requested from the operation panel 8, the print control unit 62 causes the sheets P1 to P4 placed on the sheet feeding table and the three unprinted sheets P5 placed on the sheet to be printed. Reprint against Specifically, based on the image data of the 7th page to the 5th page of the print job, duplex printing is performed on three unprinted sheets P5, and the sheet is discharged to the face-up discharge tray 58. Thereafter, based on the image data of the fourth page to the first page of the print job, printing is performed on the front side from the upper sheet P4 and is discharged to the face-up discharge tray 58.

  As a result, on the 10th to 8th pages of printed matter on which duplex printing has been completed before a transport error occurs, the 7th to 1st pages of printed matter are printed on both sides after the transport error has occurred. It is placed upward.

  5 and 6 are flowcharts showing the processing content of the printing apparatus 1 according to the first embodiment of the present invention.

  As shown in FIG. 5, when a transport error occurs during printing based on a print job instructing duplex printing (step S101), the error determination unit 61 performs single-sided printing based on the detection result of the sheet sensor. It is determined whether it is possible to continue (step 103). Specifically, when a transport error occurs in the circulation route RC, it is determined that the single-sided printing can be continued.

  If single-sided printing can be continued (step S103; YES), the error determination unit 61 stores the page number (double-sided page number, single-sided page number) that needs reprinting (step S105). The double-sided page number is the page number of the sheet P on the circulation route RC, and the unprinted sheet P is placed by the number of pages. In the example shown in FIG. 3A (a), this corresponds to the seventh to fifth pages. The single-sided page number is a page number that can be printed on one side and discharged. In the example shown in FIG. 3A (a), the fourth page corresponds to the first page.

  Next, the print control unit 62 continues single-sided printing (step S107). Specifically, the sheet P is printed on one side of the sheet P without using the circulation path RC, and the sheet is discharged to a designated sheet output tray.

  When single-sided printing is completed (step S109; YES), a reprint message is displayed on the operation panel 8 (step S111).

  Thus, single-sided printing can be continued, so even if a transport error occurs, single-sided printing can be completed until the end of the print job.

  As shown in FIG. 6, when the user places the single-sided printed sheet P and the unprinted sheet P on the sheet feeding table according to the reprint message, and instructs the reprint from the operation panel 8 ( Step S201; YES), based on the stored page numbers requiring reprinting (double-sided page number, single-sided page number) and the discharge destination designation information and the printing surface information included in the print job The print order and the discharge destination are determined (step S203).

  Next, the print control unit 62 resumes printing based on the determined printing order and the discharge destination (step S205).

  Then, when double-sided printing is completed until the end of the print job (step S207; YES), the printing process is ended.

  As described above, according to the printing apparatus 1 according to the first embodiment of the present invention, when a sheet conveyance error occurs, the error determination unit 61 determines whether the external sheet feeding path RS1, the internal sheet feeding path RS2, or the printing path If it is determined which of RP, circulation route RC, first sheet discharge route RD1 and second sheet discharge route RD2 has occurred, and the error determination unit 61 determines that a transport error has occurred on the circulation route RC, Until the print job is completed, the print control unit 62 transports the paper other than the circulation route RC, that is, the external paper feeding route RS1, the internal paper feeding route RS2, the circulation route RC, the first paper discharge route RD1, and the second discharge. The single-sided printing is continued in the printing unit 3 using the paper path RD2, and the single-sided printed paper P is discharged to the face-up paper discharge tray 58 or the face-down paper discharge tray 59.

  As a result, when a transport error occurs on the circulation path RC, single-sided printing can be continued and single-sided printing can be completed until the end of the print job. Therefore, since the remaining printing in reprinting can be reduced as much as possible, the time to complete printing can be shortened.

  For example, it is assumed that the productivity of single-sided printing of A4 paper of the printing apparatus 1 is 160 ppm and the productivity of double-sided printing of A4 paper is 80 ppm. In the case of performing double-sided printing of 800 pages (400 sheets) with this printing apparatus 1, it takes 5 minutes (5 minutes = 400 sheets (800 pages / 2 (both sides)) / 80) to finish printing. Here, right after the user instructs double-sided printing, the user leaves the printing apparatus 1 and returns after a sufficient time has elapsed (5 minutes after the scheduled print end time), but double-sided printing of 160 pages (80 sheets) is completed It is assumed that a transport error has occurred at that time.

  In this case, in the prior art, it is necessary to perform duplex printing on the remaining unprinted 640 pages (320 sheets) of paper P. In order to perform double-sided printing of 640 pages (320 sheets), four minutes are required to complete reprinting. With the exception of the error removal time, in the prior art, it takes 9 minutes (= 5 minutes + 4 minutes) in total to perform 800 pages (400 sheets) of double-sided printing.

  On the other hand, in the printing apparatus 1 according to the first embodiment of the present invention, since single-sided printing for 317 pages (317 sheets) is completed, 6 pages (three sheets) corresponding to the sheets remaining in the circulation path RC. Double-sided printing and the remaining single-sided printing of 317 pages (317 sheets) for which single-sided printing has been completed may be performed. Therefore, about 2 minutes are required to complete these printings. Except for the error removal time, the printing apparatus 1 can complete 800 pages (400 sheets) of duplex printing in about 7 minutes (= 5 minutes + about 2 minutes) in total.

  Further, according to the printing apparatus 1 according to the first embodiment of the present invention, the notification unit 63 designates the delivery destination designation information in which one of the delivery trays included in the print job is designated and the orientation of the printing surface The placement order and the number of unprinted sheets, and the placement order of single-sided printed sheets to be placed on the paper feed table as a reprint message, based on the printed surface information and the page number requiring reprinting Notice.

  As a result, if the user places the single-sided printed sheet P and the unprinted sheet P on the paper feed tray based on the reprint message, the remaining printing is continued and the single-sided print job is completed until the end Printing can be completed.

  Furthermore, when reprinting is requested, the print control unit 62 generates a single-sided printed sheet P and an unprinted sheet P based on the page number requiring reprinting, the discharge destination designation information, and the printing side information. Then, the printing order and the discharge destination are determined, and printing is performed based on the determined printing order and the discharge destination.

  As a result, it is possible to obtain a printed matter desired by the user by overlapping the printed matter whose double-sided printing has been completed before the occurrence of the conveyance error and the printed matter printed based on the remaining print job after the occurrence of the conveyance error.

<Embodiment 2 of the Present Invention>
In the second embodiment of the present invention, even when the conveyance delay of the sheet occurs due to the deterioration of the conveyance roller or the like, the erroneous determination of the sheet size mismatch is prevented.

  As described above, the printing apparatus 1 discharges ink from the nozzles of the inkjet head to print an image, characters, and the like on the sheet transported by the transport unit such as the transport roller. Therefore, since the printed sheet is conveyed while being nipped by the conveyance roller, the surface of the conveyance roller will be worn if it is used for a long time. When the surface of the conveyance roller wears, the conveyance force may be reduced and the conveyance speed may be reduced.

  On the other hand, the paper measures the paper length based on the detection result of the paper sensor, and the measured paper length (measurement paper length) and the designated paper length (designated paper length) are If different, the printing apparatus 1 determines that a sheet error has occurred.

  Therefore, when the surface of the conveyance roller is worn and the conveyance speed is slowed, the sheet length can not be accurately calculated, and the sheet error may be misjudged.

  Therefore, in the second embodiment of the present invention, an erroneous determination of a sheet error is prevented by calculating the sheet conveyance delay amount and calculating the sheet length in consideration of the conveyance delay amount.

  FIG. 7 is a flowchart showing the process contents of the printing apparatus 1 according to the second embodiment of the present invention.

  As shown in FIG. 7, when the line sensor 34 is turned on (step S303; YES) after the sheet length measurement start instruction (step S301; YES), the control unit 6 starts the sheet length measurement process. At the same time as (Step S305), a conveyance delay detection process for detecting whether or not a conveyance delay has occurred is started (Step S307).

  When the line sensor 34 is turned off by passing the conveyed sheet P immediately below the line sensor 34 (step S303; YES), the control unit 6 determines the time from the on to the on of the line sensor 34 and the conveyance speed. The sheet length is calculated as the measurement sheet length based on (step S311).

When the reverse entrance sensor 42 is turned on (Step S313; YES), the control unit 6 calculates the transport delay amount L2 using (Formula 1) and (Formula 2) below (Step S315).
T1 = L1 / V1 (Equation 1)
L2 = (T2-T1) / V1 (Equation 2)
here,
V1: Transport speed (m / s)
L1: Distance between line sensor 34 and reverse entrance sensor 42 (mm)
L2: Transfer delay (mm)
T1: Line sensor 34 to reverse inlet sensor 42 theoretical arrival time (ms)
T2: Line sensor 34 to reverse entrance sensor 42 actual conveyance time (ms)
I assume.

Next, when the calculated transport delay amount L2 exceeds the predetermined threshold, it is determined that the transport delay has occurred (step S317; YES), and the measurement sheet length is calculated using (Expression 3) below. L4 is calculated (step S319). Here, the measurement paper length (mm) is L3, and the calculation paper length (mm) is L4.
L4 = L3-L2 (Equation 3)
Then, the control unit 6 determines whether the calculated sheet length is not identical to the designated sheet length which is the designated sheet length included in the print job (step S321).

  If the calculated sheet length is not identical to the designated sheet length (step S321; YES), the control unit 6 causes the operation panel 8 to display a sheet size error (step S323).

  As described above, when the calculated sheet length considering the conveyance delay amount L2 does not match the designated sheet length, the sheet size error is displayed, so that the erroneous determination of the sheet error can be prevented.

  In the present embodiment, the conveyance delay amount L2 is calculated based on the arrival time of the line sensor 34 to the reverse entrance sensor 42, but the invention is not limited thereto.

For example, the conveyance delay amount L2 may be calculated based on the encoder pulse output from the encoder of the belt conveyance unit 33 when the sheet P reaches the reverse entrance sensor 42 using the following (Equation 4) Good.
L2 = P1 × L5-L1 (Equation 4)
here,
L5: Movement amount per encoder pulse (mm / pluse)
P1: Pulse number of encoder between line sensor 34 and reverse entrance sensor 42 (pluse)
The present invention is not limited to the above embodiment, and at the implementation stage, the constituent elements can be modified and embodied without departing from the scope of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of components disclosed in the above-described embodiment.

(Supplementary note)
The present application discloses the following invention.

(Supplementary Note 1)
A sheet feeding unit that feeds sheets placed on a sheet feeding table to a sheet feeding path one by one;
A printing unit that prints based on a print job on a sheet conveyed from the sheet feeding path to the printing path;
Switching means for reversing the front and back of the sheet printed by the printing means and switching between the circulation path circulating to the printing path and the paper discharge path for discharging the printed sheet to the paper discharge tray again ,
Any of the paper feed path, the print path, the circulation path, and the paper discharge path, when a conveyance error of the sheet occurs while the printing unit is printing based on the print job including double-sided printing Error determination means for determining whether the transport error has occurred at
When it is determined by the error determination unit that a transport error has occurred in the circulation route, the single-sided printing unit uses the sheet feed route, the print route, and the sheet discharge route until the print job ends. Print control means for continuing printing and discharging the single-sided printed paper to the paper discharge tray;
A printing apparatus comprising:

(Supplementary Note 2)
The paper discharge tray includes a face-up paper discharge tray discharged with the printing surface of the sheet facing upward and a face-down paper discharge tray discharged with the printing surface of the sheet facing downward.
The paper supply based on the paper discharge destination designation information in which any of the paper discharge trays is specified and the printing surface information in which the orientation of the printing surface is specified included in the print job, and the page number requiring reprinting The notification means for notifying the placement order, the number of unprinted sheets, and the placement order of the single-sided printed sheets placed on the paper table,
The printing apparatus according to (Appendix 1), further comprising:

(Supplementary Note 3)
The print control means
When reprinting is requested, the printing order for the single-sided printed sheet and the unprinted sheet is based on the page number requiring the reprint, the delivery destination designation information, and the printing surface information, and The printing apparatus according to (Appendix 2), wherein a discharge destination is determined, and printing is performed based on the determined printing order and the discharge destination.

Reference Signs List 1 printing apparatus 2 sheet feeding unit 3 printing unit 4 circulation conveyance unit 5 sheet discharging unit 6 control unit 7 housing 8 operation panel 18A internal sheet feeding sensor 18B internal sheet feeding sensor 18C internal sheet feeding sensor 21 longitudinal conveying sensor 32 registration sensor 33 Belt transport unit 34 Line sensor 42 Reverse entrance sensor 44 Switchback sensor 46 Double-side transport entrance sensor 48 Reverse transport sensor 49 Double-side transport exit sensor 51 First switching section 52 Upper surface transport entrance sensor 53 Second switching section 54 Lifting transport sensor 56 Sheet ejection sensor 58 face-up sheet ejection tray 59 face-down sheet ejection tray 61 error determination unit 62 print control unit 63 notification unit

Claims (3)

A sheet feeding unit that feeds sheets placed on a sheet feeding table to a sheet feeding path one by one;
A printing unit that prints based on a print job on a sheet conveyed from the sheet feeding path to the printing path;
Switching means for reversing the front and back of the sheet printed by the printing means and switching between the circulation path circulating to the printing path and the paper discharge path for discharging the printed sheet to the paper discharge tray again ,
Any of the paper feed path, the print path, the circulation path, and the paper discharge path, when a conveyance error of the sheet occurs while the printing unit is printing based on the print job including double-sided printing Error determination means for determining whether the transport error has occurred at
When it is determined by the error determination unit that a transport error has occurred in the circulation route, the single-sided printing unit uses the sheet feed route, the print route, and the sheet discharge route until the print job ends. Print control means for continuing printing and discharging the single-sided printed paper to the paper discharge tray;
A printing apparatus comprising: The paper discharge tray includes a face-up paper discharge tray discharged with the printing surface of the sheet facing upward and a face-down paper discharge tray discharged with the printing surface of the sheet facing downward.
The paper supply based on the paper discharge destination designation information in which any of the paper discharge trays is specified and the printing surface information in which the orientation of the printing surface is specified included in the print job, and the page number requiring reprinting The notification means for notifying the placement order, the number of unprinted sheets, and the placement order of the single-sided printed sheets placed on the paper table,
The printing apparatus according to claim 1, further comprising: The print control means
When reprinting is requested, the printing order for the single-sided printed sheet and the unprinted sheet is based on the page number requiring the reprint, the delivery destination designation information, and the printing surface information, and The printing apparatus according to claim 2, wherein the printing destination is determined, and printing is performed based on the determined printing order and the discharging destination.

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