Image forming apparatus and image forming method

Abstract

Even if a dedicated reversing mechanism is not provided, an index sheet can be reversed to align the index portion with a position where post-processing is performed. An image forming apparatus includes an image forming mechanism that forms a first image on one side of a sheet and passes the sheet, and is capable of forming a second image on the other side when the passed sheet is passed again; a double-sided conveying mechanism that reverses the sheet on which the first image is formed and guides the sheet to the image forming mechanism again; a post-processing unit mounting portion that is capable of mounting a post-processing unit that performs post-processing on a leading end side or a trailing end side of the discharged sheet; and a control portion that controls a print job, wherein, in a case where at least a part of the print job is a print job of an index sheet, the control portion determines whether to use the double-sided conveying mechanism to reverse the sheet, and the order of the formed images, according to which of the leading end side and the trailing end side of the sheet the post-processing unit performs post-processing.

Description

Technical Field

[0001] This disclosure relates to an image forming apparatus and an image forming method for performing a printing job, wherein at least a portion of the printing paper is index paper and post-processing is configured. Background Technology

[0002] Index paper is known to be roughly rectangular with an index portion that protrudes outwards from one side. When printing with this index paper, there is a possibility that the leading edge position of the printing paper cannot be accurately detected due to the protruding index portion. Therefore, printing is generally performed with the index portion positioned on the rear end side of the paper tray in the transport direction. On the other hand, as a post-processing process related to the completion of the printing job, such as providing punching (perforation) processing, image forming apparatuses capable of mounting post-processing units are known. Many products do not have post-processing units as standard equipment, but rather as optional accessories. In the post-processing unit, there are processing units that perform post-processing (e.g., punching) on ​​the leading edge side of the printing paper and processing units that perform post-processing on the rear end side. In such post-processing cases, it is necessary to align the orientation of the printed image with the position where the post-processing is performed.

[0003] Regarding the relationship between a printing job containing index paper on printing paper and the resulting image, an image forming apparatus is known that can output labeled paper sequentially from top of the stack of paper, even when using unwanted label paper (index paper) to output a stack of paper. The image forming apparatus includes a label paper tray with labeled paper and an output paper tray with unlabeled output paper. Furthermore, it includes a storage unit that stores label paper information related to the setting state of the labels on the label paper tray; and a control unit. Based on the label paper information stored in the storage unit, and the binding position of the stack of paper and the number of labels specified by the user, the control unit sets the image forming order, the on / off state of rotation processing, and the on / off state of reverse label paper output, controlling the output of the stack of paper mixed with label paper and output paper (for example, see Japanese Patent Application Laid-Open No. 2012-061708). Summary of the Invention

[0004] Typically, post-processing units perform post-processing on either the leading side (e.g., punching) or the trailing side. When a post-processing unit performs trailing side post-processing, it's reasonable to punch the trailing side if the index section of the index paper is located at the leading side in the transport direction. However, it's unreasonable to punch the trailing side if the index section is located at the trailing side in the transport direction. In this case, post-processing functionality cannot be provided for the printing job. Image forming apparatuses include a reversing ejection mechanism that reverses the front and back of the printed paper and transports it to the post-processing unit. However, image forming apparatuses without a reversing ejection mechanism also exist. In image forming apparatuses with a reversing ejection mechanism, the punching post-processing can be performed by switching whether the printed paper is reversed. However, image forming apparatuses without a reversing ejection mechanism require some method to reverse the index paper.

[0005] This disclosure was made with the above considerations in mind, and even without a dedicated reverse discharge mechanism, it is possible to reverse the index paper and align the index section with the position where post-processing is performed.

[0006] This invention provides an image forming apparatus comprising: a paper feeding mechanism for feeding printing paper; an image forming mechanism for forming a first image on one side of the printing paper, allowing the printing paper to pass through, and forming a second image on the other side when the passed printing paper is reversed and passes through again; a duplex conveying mechanism for reversing and guiding the printing paper with the first image formed thereon back to the image forming mechanism; a post-processing unit mounting unit for mounting a post-processing unit that performs post-processing on the front or rear side of the discharged printing paper; and a control unit for controlling printing operations. When executing a printing operation in which at least a portion of the printing paper is index paper and a post-processing function is set, the control unit determines whether post-processing can be performed, the order of the formed images, and whether the duplex conveying mechanism is used to reverse the printing paper, depending on which side of the printing paper is post-processed by the mounted post-processing unit.

[0007] Furthermore, from a different perspective, this disclosure provides an image forming method comprising: a control unit controlling a printing job using a paper feeding mechanism to supply printing paper; an image forming mechanism using an image forming mechanism to form a first image on one side of the printing paper and pass it through; a duplex conveying mechanism using a step of determining whether to reverse the printing paper with the first image formed on it and guide it back to the image forming mechanism; if guided back to the image forming mechanism, using the image forming mechanism to form or not form a second image on the other side of the printing paper and pass it through and discharge it; and a post-processing unit using a post-processing unit to perform post-processing on the front or rear side of the printing paper. When performing a printing job where at least a portion of the printing paper is index paper and post-processing is set, the order of the formed images and whether to reverse the printing paper using the duplex conveying mechanism are determined based on the type of post-processing performed on the front or rear side of the printing paper by the post-processing unit.

[0008] In the image forming apparatus of this disclosure, the control unit determines whether post-processing can be performed, the order of the formed images, and whether the double-sided conveying mechanism is used to reverse the printing paper, depending on the type of processing unit that performs post-processing on either the front or rear side of the printing paper by the installed post-processing unit. Therefore, even without a dedicated reversing ejection mechanism, the index paper can be reversed to align the index section with the position where post-processing is performed. The image forming method according to this disclosure also achieves the same effect. Attached Figure Description

[0009] Figure 1 This is a block diagram illustrating an example configuration of a multifunction printer, which is one type of image forming apparatus according to an embodiment of the present disclosure. Figure 2 It is shown Figure 1 A schematic cross-sectional view of an example configuration of the scanner section and engine section of the image forming apparatus shown. Figure 3 It is shown Figure 1 and Figure 2 This diagram illustrates how an image forming apparatus performs a printing operation using index paper with perforations. (Rear-side reference perforation) Figure 4 This illustrates the operation of the image forming apparatus when it is equipped with a reverse discharge mechanism. Figure 3 A diagram illustrating the same printing process. Figure 5 This indicates that the punching unit is used as the front-side reference when performing the operation with... Figure 3 A diagram illustrating the same printing process. Figure 6 It shows having with Figure 3 Image forming apparatuses with different paper transport paths, i.e., image forming apparatuses equipped with a reverse discharge mechanism, perform the following operations: Figure 3 A diagram illustrating the same printing operation method. (Rear-side reference punch) Figure 7 This indicates that the punching unit is used as the front-side reference when performing the operation with... Figure 6 A diagram illustrating the same printing process. Figure 8 It is shown Figure 1 The flowchart shown is an example of a process in which the control unit determines the transport path and the order of image formation based on the reference of the inversion-related mechanism and the post-processing position. Detailed Implementation

[0010] The present disclosure will now be described in further detail with reference to the accompanying drawings. Furthermore, the following description is illustrative in all respects and should not be construed as limiting the scope of the disclosure. (First Implementation) The Structure of an Image Forming Apparatus First, the image forming apparatus in this embodiment will be described. Figure 1 This is a block diagram illustrating an example configuration of a multifunction printer, representing one embodiment of the image forming apparatus. Figure 1 As shown in the block diagram, the image forming apparatus 100 includes a control unit 10, a storage unit 21, an operation unit 22, a scanning unit 24, and an image forming motor unit 30. The control unit 10 includes an operation control unit 11, a setting management unit 12, a job management unit 13, a job execution unit 14, an image processing unit 15, and a data control unit 16. The control unit 10 controls the image forming apparatus 100 and controls the image forming system, including the post-processing unit 70.

[0011] The operation unit 22 includes a display device such as an LCD screen, and displays a screen under the control of the operation control unit 11. Furthermore, the operation unit 22 includes an operation input device such as a touch panel. The operation input device detects user operations on the operation unit 22 and sends operation data to the operation control unit 11. The operation control unit 11 receives the operation data detected by the operation input device and recognizes the user's operation. The data control unit 16 controls the saving and reading of data to the storage unit 21.

[0012] The setting management unit 12 manages the settings of jobs performed by the user. The job management unit 13 handles the registration, deletion, or cessation of various jobs such as copying, scanning, and printing. When a job registered in the job management unit becomes executable, the job management unit 13 requests the job execution unit 14 to begin execution. The job execution unit 14 determines whether the job registered by the job management unit 13 can begin execution, or causes the scanning unit 24, the motor unit 30, and the image processing unit 15 to execute the job corresponding to the setting. In addition, the job execution unit 14 identifies the status detected by sensors (not shown) located in the scanning unit 24 and the motor unit 30. Then, it controls the operation of motors, actuators, devices, etc. (not shown) located in the scanning unit 24 and the motor unit 30. The image processing unit 15 controls image-related processing. It also performs job-related processing such as reading, printing, and previewing the original image.

[0013] In its specific configuration, the control unit 10 is centered around a processor. Based on the processor, it comprises hardware resources such as working memory, input / output interface circuits, timer circuits, image processing circuits, and communication circuits. The processor executes control programs pre-stored in the storage unit 21 to perform various tasks related to operation recognition, display control, reading of original images, and image printing—that is, a series of processes related to image formation. Software and hardware resources cooperate to realize the functions of the control unit 10.

[0014] The storage unit 21 includes volatile memory such as DRAM and non-volatile memory such as HDD and flash memory. The storage unit 21 stores control programs executed by the processor, image data read by the scanning unit 24 and processed by the image processing unit 15. It also stores data related to the control of the data control unit 16, the job management unit 13, the job execution unit 14, and the image processing unit 15. The storage unit 21 may also be integrated with the memory of the control unit 10.

[0015] The control unit 10 and the engine unit 30, and the control unit 10 and the scanning unit 24 are connected in a manner that enables data transmission. Figure 2 It is shown Figure 1The image forming apparatus 100 shown is illustrated in a schematic cross-sectional view of its scanning unit 24 and motor unit 30 configuration example. The scanning unit 24 includes an image reading unit 25 and a document transport device 28. The document transport device 28 is positioned above the image reading unit 25 and is supported relative to the document stage 26 disposed on the top surface of the image reading unit 25, allowing it to open and close freely. The document transport device 28 transports one or more original documents sequentially, one at a time. The scanning unit 24 reads the original documents transported sequentially by the document transport device 28 via an image sensor 29. Furthermore, the scanning unit 24 includes a scanning optical system 27. The scanning optical system 27 scans the document stage 26 and reads the original documents via the image sensor 29. Then, image data of the read original documents is generated.

[0016] The engine unit 30 includes a paper feeding mechanism 60, an image forming mechanism 40, a duplex conveying mechanism 31, and a post-processing unit mounting section 32. The paper feeding mechanism 60 holds and supplies printing paper for printing operations. The image forming mechanism 40, for example, in the case of electrophotographic printing, uses toner to form a visual image, transfers it to the printing paper, fixes it, and thus performs printing. Alternatively, for example, in the case of inkjet printing, printing is performed by forming an ink-based visual image on the printing paper. The duplex conveying mechanism 31 reverses the printing paper with the printed image, and guides the printing paper back to the image forming mechanism via a reverse conveying path 34.

[0017] The image forming mechanism 40 forms color images using black (K), cyan (C), magenta (M), and yellow (Y) or monochrome images using a single color (e.g., black). The image forming mechanism 40 is equipped with four developing units 41, a photosensitive drum 42, a drum cleaning unit 43, and a belt charger 44 for forming images with four different tones, corresponding to black, cyan, magenta, and yellow respectively, forming four image stations Pa, Pb, Pc, and Pd. Furthermore, the image forming mechanism 40 includes a light scanning device 45 that exposes the surface of the photosensitive drum 42 to form an electrostatic latent image.

[0018] The developing unit 41 develops the electrostatic latent image on the surface of the photosensitive drum 42, forming a toner image on the surface of the photosensitive drum 42. The drum cleaning unit 43 removes and recovers residual toner from the surface of the photosensitive drum 42. The charging unit 44 uniformly charges the surface of the photosensitive drum 42 to a predetermined potential. Through the above series of actions, toner images of various colors are formed on the surface of each photosensitive drum 42.

[0019] Furthermore, the image forming apparatus 40 includes intermediate transfer rollers 46, annular (endless) intermediate transfer belts 47, intermediate belt drive rollers 48, intermediate belt driven rollers 49, and a belt cleaning device 50. Four intermediate transfer rollers 46 are respectively arranged inside the intermediate transfer belt 47 to form four toner images corresponding to each color. The intermediate transfer rollers 46 transfer the toner images of each color formed on the surface of the photosensitive drum 42 to the surrounding moving intermediate transfer belt 47. The intermediate transfer belt 47 is supported by the intermediate belt drive roller 48 and the intermediate belt driven roller 49. In the image forming apparatus 100, the toner images of each color formed on the surface of each photosensitive drum 42 are sequentially transferred and overlapped to form a colored toner image on the surface of the intermediate transfer belt 47. The belt cleaning device 50 removes and recovers waste toner that has not been transferred to the printing paper and remains on the surface of the intermediate transfer belt 47.

[0020] Furthermore, the image forming mechanism 40 includes a secondary transfer unit 51 and a fixing unit 53. The secondary transfer unit 51 has a secondary transfer roller 52, which clamps the printing paper fed from the paper feeding mechanism 60 into a transfer clamping section between the secondary transfer roller 52 and the intermediate transfer belt 47 for transport. As the printing paper passes through the transfer clamping section, the toner image on the surface of the intermediate transfer belt 47 is transferred and transported to the fixing unit 53, which is positioned above the secondary transfer unit 51. The fixing unit 53 includes a fixing roller 54 that rotates about an axis and a pressure roller 55 as rotating fixing components. The fixing unit 53 clamps the printing paper fed from the transfer clamping section between the fixing roller 54 and the pressure roller 55 and heats and presses it to fix the toner image onto the printing paper.

[0021] The paper feeding mechanism 60 includes a paper feeding tray 61, a manual tray 62, a paper feeding roller 63, a manual paper feeding roller 64, and a positioning roller 65. The paper feeding mechanism 60 feeds sheets of printing paper one by one from the paper feeding tray 61 containing printing paper via the paper feeding roller 63 and conveys them to the positioning roller 65, and conveys them to the transfer clamping unit in a manner that synchronizes the image on the intermediate transfer belt 47 with the position of the printing paper. Similarly, printing paper placed on the manual tray 62 is fed one by one and conveyed to the positioning roller 65, and further conveyed to the transfer clamping unit. During printing, the image is transferred onto the printing paper using the transfer clamping unit. In this invention, the setting management unit 12 receives settings for the type of printing paper contained in the paper feeding tray 61 and the type of printing paper (paper type) provided in the manual tray 62. As one of the settable paper types, index paper is assumed. When performing a print job that includes index paper, the user places the index paper on a designated tray (e.g., a manual tray) and uses the operation unit 22 to set the paper type of the manual tray to index paper.

[0022] The double-sided conveying mechanism 31 includes an ejector roller 33 and a reverse conveying path 34. When the rear end of the printing paper, which has passed through the transfer clamp and fixing unit 53, reaches the ejector roller 33, the control unit 10 reverses the printing paper, i.e., conveys it in the opposite direction, and guides it to the reverse conveying path 34. The printing paper, having passed through the reverse conveying path 34, is then guided back to the positioning roller 65 in a reversed state. The control unit 10, acting as the operation execution unit 14, then conveys the printing paper guided to the positioning roller 65 back to the transfer clamp and fixing unit 53. In the case of double-sided printing, the image is transferred when passing through the transfer clamp. Then, the printing paper is conveyed to the left end of the engine unit 30 via the fixing unit 53 and the ejector roller 33. A post-processing unit mounting section 32 is provided at the left end of the engine unit 30. The post-processing unit mounting section 32 is used to position the post-processing unit 70, which can be mounted on the left side of the engine section 30, and to discharge printing paper from the engine section 30 to the mounted post-processing unit 70. For example, a positioning pin may be provided in the post-processing unit 70, and a hole may be provided in the post-processing unit mounting section 32 for inserting the pin. Alternatively, an opening for discharging printing paper may be provided.

[0023] The post-processing unit 70, installed at the left end of the engine section 30, may also include a punching unit 71 for punching printing paper as post-processing, a binding unit 72 for printing and binding, and a paper folding unit 73 for folding paper (see reference). Figure 1 The punching unit 71 punches either the front or rear side of the printing paper fed to the post-processing unit 70. The binding unit 72 also binds the printing paper on either the front or rear side. The paper folding unit 73 folds the paper (e.g., Z-fold) with either the front or rear side as a reference. The reference for the post-processing position in the post-processing unit is the same as either the front or rear side. That is, if the punching unit 71 is a unit based on the front side, then the binding unit 72 and the paper folding unit are also units based on the front side. If the punching unit 71 is a unit based on the rear side, then the binding unit 72 and the paper folding unit are also units based on the rear side. Furthermore, the post-processing unit 70 includes a discharge tray 74 for discharging the post-processed printing paper and a post-processing control unit 75 that communicates with the control unit 10 and controls the post-processing operation.

[0024] Printing and post-processing of index paper right Figure 1 and Figure 2 The process of the image forming apparatus 100 shown performing a print job with at least a portion of the printing paper being index paper and post-processing set will be described. Figure 3This is an explanatory diagram showing how the image forming apparatus 100 performs a printing job using index paper and with punching as a post-processing step. The punching is identical across all completion states, and based on this, punching is a preferred post-processing step in embodiments of this disclosure.

[0025] Figure 3 The print job shown is a multi-page print job using index paper. With the index section at the rear end, index paper is supplied from the paper feed mechanism 60 of the image forming apparatus 100. An image is formed on the first side of each index paper, but not on the second side; post-processing, including punching, is then performed. The punching unit punches holes at the rear end of the print paper. The image forming apparatus 100 includes a rear-end-side-referenced punching unit 71 and a duplex conveying mechanism 31, but lacks a reverse ejection mechanism. The setting management unit of the control unit 10 stores information related to these configurations in advance in the storage unit 21. Then, based on the settings of the print job to be executed and the configuration of the image forming apparatus 100, the paper feed path and the order of the formed images are determined in a completed state arranged in page order.

[0026] exist Figure 3 In the example shown, the illustration indicated by reference numeral P1 shows the orientation of the index paper placed on the manual tray 62 in its position as viewed from above. Furthermore, the illustration indicated by reference numeral P2 shows the paper being transferred via the intermediate transfer belt 47 and the secondary transfer roller 52. Figure 3 The images on the index paper between the transfer clamps (not shown in the image) are arranged in descending order from the last page to the first page. The illustration on page 2 shows the state of the index paper as viewed from the side of the middle transfer belt 47.

[0027] exist Figure 3 In the example shown, the control unit 10 reaches the discharge roller 33 at the rear end of the index paper after passing through the transfer clamping unit. Figure 3 When the index paper (not shown) is in front of the position, it is reversed and guided to the double-sided conveyor 31, and then conveyed to the post-processing unit 70 after passing through the transfer clamp. The illustration shown by reference numeral P3 shows the state of the index paper when it is reversed, viewed from above. As shown in P3, the toner image is facing down. The reversal reverses the front and back sides. Therefore, when it passes through the discharge roller 33 again via the double-sided conveyor 31, the index section is on the front side and the toner image being transferred is on the upper side of the index paper. The punching unit 71 punches holes on the rear side. The illustration shown by reference numeral P4 shows the state of the index paper with punched holes and discharged to the discharge tray 74, viewed from above. The last page is at the bottom, the first page is at the top, and the transferred image is on the upward-facing side. The punched holes are on the side opposite to the index section and arranged in page order in the finished state. Figure 3In the manner shown, where the post-processing unit performs post-processing on the back end without a reverse ejection mechanism, the printing job can be performed by forming an image in descending order of pages and using a double-sided conveying mechanism to reverse the printing paper, thereby obtaining a completed state in which post-processing has been performed and the pages are arranged in order.

[0028] Figure 4 The composition of the post-processing unit 70 and Figure 3 The examples shown are different from the examples shown. Figure 4 The post-processing unit 70 shown has a reversing discharge mechanism 66 upstream of the transport path leading to the punching unit 71. The control unit 10 can use the reversing discharge mechanism 66 to reverse the index paper that has passed through the transfer clamp and guide it to the punching unit 71. During the execution of... Figure 3 In the example shown, for the same printing job, the control unit 10 determines the paper feed path and the order of the formed images in a manner that results in a completed state with pages arranged in sequence, based on the settings of the printing job to be performed and the configuration of the image forming apparatus 100.

[0029] exist Figure 4 In the example shown, the control unit 10 forms images from the last page to the first page, i.e., in descending order, and feeds the index paper that has passed through the transfer clamping unit to the post-processing unit 70 without reversing it to the double-sided conveying mechanism 31. Then, after being reversed by the reversing discharge mechanism 66 of the post-processing unit 70, it is fed to the punching unit 71. Reference numerals P1 to P4 are... Figure 3 Similarly, the diagram shows the index paper in the manual tray 62, the state with the image transferred in the transfer clamp, the state reversed by the reverse discharge mechanism 66, and the state discharged to the discharge tray 74. Reference numeral P3 indicates the state of the index paper being fed to the post-processing unit 70 from above, i.e., the state before reversal. Until reversal, the index section is located on the rear end side. Due to the reversal, the inside and outside are reversed, and the index section is located on the front end side. Therefore, when the index paper is guided to the punching unit 71, the toner image transferred by the index section on the front end side is located on the upper side of the index paper. The punching unit 71 punches holes on the rear end side. The illustration shown by reference numeral P4 is related to... Figure 3 The same state. That is, the last page is at the bottom, the first page is at the top, and the transferred image is on the upward-facing side. The punching is on the side opposite to the index section and arranged in page order in the finished state. According to Figure 3 as well as Figure 4 As shown, when the image forming apparatus 100 is equipped with a reversing discharge mechanism 66, the control unit 10 can determine the order of the images to be formed and whether the reversing paper is reversed by the double-sided conveying mechanism 31 or by the reversing discharge mechanism 66, depending on whether the reversing paper is reversed.

[0030] Figure 5The composition of the post-processing unit 70 and Figure 3 and Figure 4 The examples shown are different from the examples shown. Figure 5 The post-processing unit 70 shown does not have a reverse discharge mechanism 66, and the punching unit 71 has punches on the front end side. exist Figure 5 In the example shown, the control unit 10 forms images in ascending order (page sequence), and conveys the index paper, which passes through the transfer clamp without causing the double-sided conveyor 31 to reverse, to the post-processing unit 70. The punching unit 71 punches a hole in the front end of the index paper, discharging it onto the discharge tray 74. (See attached figures P1-P4.) Figure 3 and Figure 4 Similarly, the following states are shown: index paper set on manual tray 62; image transferred to transfer clamp; reversed by reverse ejection mechanism 66; and ejected to ejection tray 74. Reference numeral P3 indicates the state of index paper being fed to post-processing unit 70 as viewed from above. When the index paper is guided to punching unit 71, the toner image transferred to the rear end of the index section is located on the lower side of the index paper. Punching unit 71 has punches on the front end side. As shown in the illustration with reference numeral P4, the first page of the index paper ejected to ejection tray 74 is at the bottom, the last page is at the top, and the transferred image is on the downward-facing side. The punches are located on the side opposite to the index section and arranged in page order in the completed state. Figures 3 to 5 As shown, the control unit 10 can determine the order of the formed images and whether to reverse the index paper based on whether the punching unit 71 is a front-side reference or a rear-side reference.

[0031] Figure 6 and Figure 7 and Figures 3 to 5 Compared to the example shown, the paper transport path of the image forming apparatus 100 is configured differently. Figure 6 and Figure 7 The image forming apparatus 100 shown transfers a toner image after the supplied index paper is transported to the left end of the intermediate transfer belt 47 via a transport path below the intermediate transfer belt 47. That is, the transfer clamping part is located on the left end of the intermediate transfer belt 47. The double-sided transport mechanism 31 is located further to the left of the transfer clamping part. The part that reverses the index paper via the transfer clamping part is located above the transfer clamping part. After guiding the index paper to the right-hand reversal path, the transport direction is reversed and the paper is guided to the left-hand double-sided transport mechanism 31. Since the transport direction of the reversed index paper is towards the post-processing unit 70, the transport path can be easily switched to guide it towards the post-processing unit 70, thereby replacing guiding the index paper to the double-sided transport mechanism 31. In other words, in the image forming apparatus 100 equipped with... Figure 6 as well as Figure 7In the case of the paper transport path shown, it is easy to set up a reverse discharge mechanism 66. Figure 6 The image forming apparatus 100 is shown to include a reverse discharge mechanism 66. Furthermore, in Figure 6 In the middle, the punching unit 71 has punching holes on the rear end side.

[0032] exist Figure 6 In the example shown, the control unit 10 forms images in ascending order (page sequence), and reverses the index paper that has passed through the transfer clamping unit, instead of guiding it to the double-sided conveying mechanism 31, using the reverse discharge mechanism 66 to convey it to the post-processing unit 70. Then, the punching unit 71 punches a hole on the rear end side of the index paper, discharging it to the discharge tray 74. Reference numerals P1, P2, and P4 are... Figures 3-5 Similarly, the diagram shows the index paper in the manual tray 62, the state with the image transferred in the transfer clamp, the state reversed by the reversing ejection mechanism 66, and the state ejected to the ejection tray 74. Reference numeral P3 indicates the state of the index paper being reversed and guided to the punching unit 71, viewed from above. When the index paper is guided to the punching unit 71, the toner image transferred to the front end of the index section is located on the lower side of the index paper. The punching unit 71 has punches on the rear end side. As shown in the illustration with reference numeral P4, the first page of the index paper ejected to the ejection tray 74 is at the bottom, the last page is at the top, and the transferred image is on the downward-facing side. The punches are located on the side opposite to the index section and arranged in page order in the completed state.

[0033] Figure 7 In the middle, the configuration of the post-processing unit 70 and Figure 6 Unlike the example shown, punching unit 71 has punches on the front end side. Figure 7 In the example shown, the control unit 10 forms images in reverse order, i.e., descending order, and feeds the index paper, which has passed through the transfer clamp, to the post-processing unit 70. Then, the punching unit 71 punches a hole in the leading edge of the index paper, discharging it onto the discharge tray 74. Reference numerals P1, P2, and P4 are... Figures 3-6 Similarly, the diagram shows the index paper in the manual tray 62, the image transferred to the transfer clamp, and the paper being ejected to the ejection tray 74. Reference numeral P3 indicates the state of the index paper being guided to the punching unit 71 from above. When the index paper is guided to the punching unit 71, the toner image transferred to the rear end of the index section is located on the upper side of the index paper. The punching unit 71 has punches on the front end side. As shown in the illustration with reference numeral P4, the last page of the index paper ejected to the ejection tray 74 is at the bottom, the first page is at the top, and the image transferred is on the upward-facing side. The punches are located on the side opposite to the index section and arranged in page order in the completed state.

[0034] In this embodiment, an example is described above: Index paper is supplied with the index section positioned at the rear end, passes through the positioning roller 65 and the transfer clamping section, and is discharged after being reversed by the double-sided conveying mechanism 31. When the index paper initially passes through the transfer clamping section after being supplied, the control unit 10, which is the work execution unit 14, transfers the toner image to the first side of the index paper according to a setting. However, when the index paper passes through the positioning roller 65 and the transfer clamping section again after being reversed, the control unit 10, which is the work execution unit 14, does not allow the toner image to be transferred to the second side of the index paper. At this time, since the index section is at the front end and passes through the positioning roller 65, there is a possibility that the toner image cannot be correctly aligned with the position of the index paper, so this is configured.

[0035] The control unit determines the image formation order and inversion processing. Next, referring to the flowchart, an example of the process by which the control unit 10 determines the transport path and the order in which the images are formed will be explained. Figure 8 It means Figure 1 The flowchart shown illustrates an example of how the control unit determines the transport path and image formation sequence based on the references of the mechanisms involved in the reversal and the post-processing position. Furthermore, Figure 8 The flowchart assumes that the engine section 30 has Figures 3-5 The conveying path is shown. Figure 8 As shown, when the control unit 10, which is the job execution unit 14, receives an instruction to execute a print job, it determines whether at least a portion of the printing paper contains index paper (step S11). If the paper does not contain index paper (no in step S11), the normal print job-related processing is performed (step S13), and the processing ends.

[0036] On one hand, if the printing paper includes index paper (as in step S11), the control unit 10 determines whether a post-processing operation (punching in the flowchart) is set (step S15). If punching is not set (no in step S15), it decides to print in page order without reversing the index paper (step S17), executes the printing job according to the decision (step S29), and ends the process. On the other hand, if punching is set (as in step S15), the control unit 10 then determines whether the post-processing position of the punching unit 71 is a rear-side reference or a front-side reference (step S19). If it is a front-side reference (no in step S19), it decides to print in page order without reversing the index paper (step S17), executes the printing job according to the decision (step S29), and ends the process.

[0037] On the other hand, if the post-processing position of the punching unit 71 is the rear-end reference (yes in step S19), the control unit 10 then determines whether the image forming apparatus 100 has a reverse ejection mechanism (step S21). If a reverse ejection mechanism is present (no in step S21), the control unit 10 decides to reverse the index paper using the reverse ejection mechanism 66 and print in page order (step S23), executes the printing job according to the decision (step S29), and ends the processing. If the image forming apparatus 100 includes a reverse ejection mechanism (yes in step S21), the control unit 10 then determines whether printing paper other than index paper that does not pass through the reverse transport path 34 of the duplex conveyor 31 is included (step S25). Furthermore, it is assumed that the index paper passes through the duplex conveyor 31. When printing paper of a type that does not pass through the reverse transport path 34 is included (No in step S25), the control unit 10 decides not to reverse the index paper and print in page order (step S17), executes the printing job according to the decision (step S29), and ends the process.

[0038] On the other hand, in the case of printing paper that does not include paper types that pass through the reverse transport path 34 (as in step S25), the control unit 10 decides to form the image in descending order of pages and uses the duplex transport mechanism 31 to reverse the printing paper. Based on reversing the inside and outside, post-processing punching is performed at the rear end. As described above, the control unit 10 determines the image formation order and the transport path that may include the reversed paper.

[0039] (Second Implementation) In the first embodiment, a printing job in which all printing paper is index paper was described as an example. However, there are also printing jobs in which the printing paper includes printing paper other than index paper. For example, the paper tray 61 is set to hold printing paper of the type of plain paper, and the manual tray 62 is set to hold printing paper of the type of index paper, and the printing job is set to insert the index paper into the specified pages. For such printing jobs, the control unit 10, as in the first embodiment, determines the paper transport path and the image formation order based on whether post-processing is present, whether the post-processing unit is a front-side reference or a rear-side reference, and whether a reverse ejection mechanism is present. According to this method, even when the printing job includes printing paper other than index paper, the printing job can be completed in a state where the pages are arranged in order and post-processing is completed.

[0040] Furthermore, as described in the first embodiment, the control unit 10 does not allow printing on the second side of index paper that has been reversed. However, for printing paper other than index paper, if it is not a type that cannot be printed on both sides, such as thick paper, printing on the second side is permitted. If the printing paper includes a type that cannot be transported using a duplex conveyor, the control unit 10 determines that reversal using the duplex conveyor is not allowed. Therefore, for index paper, in the case of a printing job where reversal is performed using a duplex conveyor, if the printing paper includes a type that cannot be transported using a duplex conveyor, the control unit determines that it is a printing job that cannot be post-processed. According to this method, if a printing job in which index paper is reversed using a duplex conveyor includes printing paper other than index paper, and this printing paper cannot be reversed by the duplex conveyor, the control unit sets it to not be able to set post-processing, or even if it is set, not to perform post-processing, regardless of whether duplex printing is performed. This prevents poor paper transport and paper jams.

[0041] When the index paper with the index section at the rear end passes through the positioning roller 65, the control unit 10, which is the work execution unit 14, maintains the positioning roller 65 in a stopped state when the front end reaches the positioning roller 65. Control is performed in a manner that allows the index paper to be conveyed after deflection, suppressing tilting of the index paper and ensuring alignment with the toner image. However, after reversal, different control is performed when the index paper with the index section at the front end passes through the positioning roller 65. The index paper is not stopped at the positioning roller 65. There are multiple types of index paper with different positions where the index sections are formed in the width direction orthogonal to the conveying direction. Even if a sensor is placed at a predetermined position in the width direction to detect the front end of the printing paper, it is difficult to determine whether the detected part is the front end of the index section or the front end of a non-index section. In other words, when the index section is at the front end, it is difficult to suppress tilting of the positioning roller 65 and difficult to ensure alignment with the toner image. Therefore, the control unit 10, acting as the work execution unit 14, does not stop the index paper at the positioning roller 65, nor does it allow the transfer of the toner image to the second side of the index paper. For example, if the control unit is set to form an image on the first side when the index section of the index paper is in the rear-end position after being fed from the paper feeding mechanism, then image formation is allowed, but image formation is not allowed on the second side when the index section is in the front-end position after reversal. In this way, positional offsets caused by the index paper and image not being properly aligned in the transport direction of the image forming mechanism can be prevented.

[0042] (Fourth Implementation) In the first embodiment, the engine unit 30 is shown to include a double-sided conveying mechanism 31 and a paper feeding mechanism 60, and the punching unit 71, the packing unit 72, and the paper folding unit 73 are included in a post-processing unit 70 that is different from the engine unit 30. However, this disclosure is not limited to this configuration. For example, the double-sided conveying mechanism 31 and the paper feeding mechanism 60, which are provided as double-sided units different from the engine unit 30, are also included within the scope of this disclosure. Furthermore, the configuration of the engine unit 30 including at least one of the packing unit 71, the packing unit 72, and the paper folding unit 73 is also included within the scope of this disclosure. In addition, besides the configuration where the punching unit 71, the packing unit 72, and the paper folding unit 73 are included in one post-processing unit 70, the configuration where they can be divided into multiple post-processing units is also included within the scope of this disclosure.

[0043] This disclosure should be understood to include combinations of any one of the above methods. In addition to the embodiments described above, this disclosure may have various modifications. These modifications should not be construed as being outside the scope of this disclosure. The invention as described herein should include all modifications equivalent to the claims and falling within the scope of this disclosure.

Claims

1. An image forming apparatus, characterized in that, have: Paper supply organizations provide printing paper; The image forming mechanism forms a first image on one side of the printing paper, allows the printing paper to pass through, and is able to form a second image on the other side when the passing printing paper is flipped and passes through again; A double-sided conveying mechanism reverses the printing paper with the first image formed on it and guides it back to the image forming mechanism; The post-processing unit mounting section is capable of mounting a post-processing unit that performs post-processing on the front or rear side of the ejected printing paper; as well as Control department, controls printing jobs. When executing a printing job in which at least a portion of the printing paper is index paper and a post-processing function is set, the control unit determines whether post-processing can be performed, the order of the formed images, and whether the duplex conveyor mechanism should be used to reverse the printing paper, depending on whether the installed post-processing unit performs post-processing on the front or rear side of the printing paper.

2. The image forming apparatus as claimed in claim 1, characterized in that, When the paper feeding mechanism is configured to feed the index paper with the index section as the rear end, and the post-processing unit performs post-processing on the rear end of the printing paper, the control unit forms an image on the supplied printing paper in descending order, and discharges it after being reversed by the double-sided conveying mechanism.

3. The image forming apparatus as claimed in claim 2, characterized in that, It has a reversing discharge mechanism that arbitrarily reverses and discharges the printing paper passing through the image forming mechanism. The control unit determines the order of the formed images and whether the index paper is reversed by the double-sided conveying mechanism based on the presence or absence of the reversing discharge mechanism and the type of the post-processing unit.

4. The image forming apparatus as claimed in claim 2, characterized in that, When the printing job includes printing paper other than index paper, the control unit forms an image on the printing paper supplied in descending order, including the printing paper other than index paper, and discharges it after being reversed by the duplex conveyor mechanism.

5. The image forming apparatus as claimed in claim 2, characterized in that, The control unit allows image formation when the index paper passes through the image forming mechanism while the index section is at the rear end, and disallows image formation when the index section is at the front end.

6. The image forming apparatus as claimed in claim 4, characterized in that, If the printing paper other than the index paper is a type that cannot be transported by the duplex conveyor, the control unit determines that it is a printing job that cannot be post-processed and sets it to not perform post-processing.

7. The image forming apparatus according to any one of claims 1-6, characterized in that, The post-processing is punching.

8. An image forming method, characterized in that, The control unit that controls the printing job includes: The steps of using a paper supply mechanism to supply printing paper; The step of forming a first image on one side of the printing paper using an image forming mechanism and passing it through; The step of using a double-sided conveying mechanism to determine whether to reverse the printing paper with the first image formed on it and guide it back to the image forming mechanism; In the case of guiding the image forming mechanism again, the image forming mechanism is used to form or not form a second image on the other side of the printing paper, allowing it to pass and be discharged. as well as The step of using a post-processing unit to perform post-processing on the front or back side of the printing paper. When performing a print job in which at least a portion of the printing paper is index paper and post-processing is set, the order of the formed images and whether to use the duplex conveyor mechanism to reverse the printing paper are determined based on the type of post-processing performed on the front or rear side of the printing paper by the post-processing unit.

Images