Image reading device and image formation apparatus

Abstract

To allow a user to easily change the front-back relationship of an image on one surface and an image on the other surface of a document when the front and back surfaces of the document are read incorrectly.SOLUTION: In an image reading device 20, a control unit 29 sets a conveyed document double-surface reading mode, causes a second imaging unit 42 to read an image on one surface of the document, causes the second imaging unit 42 to read an image on the other surface of the document when the document is flipped and placed again on a document tray 33, causes a display unit 24 to display the images by associating the image on the one surface and the image on the other surface of the document, causes the display unit 24 to display options to choose which image of the image on the one surface and the image on the other surface of the document is the image on the front surface, and sets one of the image on the one surface and the image on the other surface of the document as the image on the front surface according to the operation of an operation unit.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image reading device that reads an image of a document while the document is transported through one of a plurality of transport paths, and an image forming apparatus equipped with the same, and more particularly to a technique for dealing with the case where the front and back of the document are erroneously read. [Background technology]

[0002] Some image reading devices are configured to pull out an original from a document tray and transport it through one of a number of transport paths, read an image of one side of the original being transported through one transport path using an imaging unit, read an image of the other side of the original being transported through another transport path using another imaging unit, and discharge the original from each transport path to the respective output tray.

[0003] In the data processing device described in Patent Document 1, an image reading unit reads images of the front sides of multiple documents and stores them in a memory unit, data indicating which page it is is added to the image of the front side of each document, and the image reading unit also reads images of the back sides of each document and stores them in a memory unit, data indicating which page it is added to the image of the back side of each document, and it is determined whether the images on the front and back sides of each document are in normal or reverse order, and if they are in normal order, the nth images of the front and back sides of each document are paired and filed, and if they are in reverse order, the nth image of the front side of each document is paired and filed with the N-n+1th image of the back side of each document (N is the total number of documents).

[0004] In addition, the image reading device described in Patent Document 2 includes a first reading means for reading a front image of a document, a second reading means for reading a back image of the document, and a printing means for printing the front image read by the first reading means or the back image read by the second reading means on the front or back of a sheet, and determines the acquisition order of the front image read by the first reading means and the back image read by the second reading means based on the sheet feed conditions and post-processing conditions, and outputs the front image and back image acquired in accordance with this determined acquisition order to the printing means. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-025101 [Patent Document 2] JP 2017-103512 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration described above in which the document is transported through the transport path and the image of one side of the document is read by the imaging unit, if the document to be read is turned over and the image of the other side of the document is read again by the imaging unit, the images of both sides of the document can be read. However, if the user mistakenly places the document upside down, the front and back of the document will be read incorrectly. In this case, it is necessary to later reverse the relationship between the front and back of the image of one side of the document that has been read and the image of the other side of the document to return it to the original state.

[0007] In Patent Document 1, the procedure for pairing the image on the front side of each document with the image on the back side of each document is changed depending on whether the image on the front side of each document and the image on the back side of each document are in normal or reverse order, thereby matching the page order of the front side of each document with the page order of the back side of each document. However, this does not address the case where the front and back of a document are read incorrectly, as described above.

[0008] In addition, in Patent Document 2, the order of acquiring the front image read by the first reading means and the back image read by the second reading means is determined, but again, it does not deal with the case where the front and back of the document are mistakenly read as described above.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and aims to enable a user to easily change the relationship between the front and back of an image on one side of a document and the image on the other side of the document when the user mistakenly reads the front and back of the document in a double-sided document reading operation in which the imaging unit reads an image on one side of the document and then inverts the document to be read to read, thereby reading an image on the other side of the document. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided an image reading device including a display unit, an original tray on which a plurality of originals are placed, a straight transport path for transporting the plurality of originals drawn from the original tray, a curved transport path branching off from the straight transport path, a first imaging unit for reading images of the faces of the plurality of originals facing upward on the original tray while the plurality of originals are transported through the curved transport path, a second imaging unit provided upstream in a document transport direction from a branching position of the straight transport path and the curved transport path, and for reading images of the faces of the plurality of originals facing downward on the original tray while the plurality of originals are transported through the straight transport path, and a memory that temporarily stores an image read by the second imaging unit; an operation unit that receives instructions from a user; and a control unit that performs operation control in a transported document double-sided reading mode in which the multiple documents pulled out from the document tray are transported through the linear transport path, images of the multiple documents facing downward on the document tray are read by the second imaging unit, and when the multiple documents are subsequently placed on the document tray again, the multiple documents pulled out from the document tray are transported through the linear transport path, and images of the multiple documents facing downward on the document tray are read by the second imaging unit, When an instruction to execute the double-sided reading mode is received from the operation unit, the control unit controls operation in the double-sided reading mode, causes the display unit to display each image obtained in the first reading by the second imaging unit and each image obtained in the second reading by the second imaging unit, and, in accordance with the instruction received from the operation unit, sets either the images obtained in the first reading or the images obtained in the second reading as the front image collectively, and sets the other as the back image collectively.

[0011] In addition, an image forming apparatus according to one aspect of the present invention includes the image reading device according to the above-mentioned aspect of the present invention, and an image forming section that forms an image of a document read by the image reading device on recording paper. Effect of the Invention

[0012] According to the present invention, when performing double-sided document reading in which an image of one side of a document is read by an imaging unit, and an image of the other side of the document is read by the imaging unit on the premise that the document to be read is inverted and made the front and back sides to be read, if a user mistakenly reads the front and back sides of the document, the relationship between the front and back of the image of one side of the document and the image of the other side of the document can be easily changed. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing an image forming apparatus to which an image reading apparatus according to an embodiment of the present invention is applied; [Diagram 2] FIG. 2 is a cross-sectional view showing an image reading device. [Diagram 3] FIG. 1 is a perspective view showing an external appearance of an image reading device. [Figure 4] FIG. 2 is an enlarged view showing a document transport path in the image reading device. [Diagram 5] 13 is an enlarged view showing another transport path for a document in the image reading device; FIG. [Figure 6] 1 is a block diagram showing a main internal configuration of an image forming apparatus; [Figure 7A]11 is a flowchart showing a control procedure for dealing with an erroneous operation in which an original is placed on the original tray with its front side facing up when the original is read in the second transported original double-sided reading mode. [Figure 7B] 7B is a flowchart showing the control procedure following FIG. 7A. [Figure 7C] 7C is a flowchart showing a control procedure subsequent to FIG. 7B. [Figure 8] FIG. 13 is a diagram showing a message displayed on a display unit. [Figure 9] (A) shows the relationship between the front and back of the document when it is read with its front side facing down, and then flipped over and read, while (B) shows the relationship between the front and back of the document when it is read with its front side facing down, and then read without flipping it over. [Figure 10] (A) shows the relationship between the front and back of a document when the back side of the document is read face down, and then the document is flipped over and read, and (B) shows the relationship between the front and back of a document when the back side of the document is read face down, and then the document is read without being flipped over. [Figure 11] FIG. 13 is a diagram showing another message displayed on the display unit. [Figure 12] This figure shows the front and back of the images on one side and the other side of each document placed face down on the document tray before reading begins, and read in the second transport document double-sided reading mode. [Figure 13] (A) is a diagram showing the front and back of the images on one side and the other side of each document read in the second transport document double-sided reading mode after the document was mistakenly placed on the document tray with its front side facing up before reading began, and (B) is a diagram showing the front and back of the images on one side and the other side of each document swapped all at once. [Figure 14] FIG. 4 is a diagram showing an editing screen displayed on a display unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing an image forming apparatus to which an image reading device according to an embodiment of the present invention is applied. As shown in Fig. 1, an image forming apparatus 10 includes an image reading device 20 and an image forming unit 21 according to the present embodiment.

[0015] The image reading device 20 has an imaging section (CCD sensor, contact image sensor) that optically reads an image of a document, and the analog output of this imaging section is converted into a digital signal to generate image data representing the image of the document.

[0016] The image forming section 21 prints an image represented by the image data on a recording sheet, and includes an image forming unit 3M for magenta, an image forming unit 3C for cyan, an image forming unit 3Y for yellow, and an image forming unit 3Bk for black. In each of the image forming units 3M, 3C, 3Y, and 3Bk, the surface of the photosensitive drum 4 is uniformly charged, the surface of the photosensitive drum 4 is exposed to light, an electrostatic latent image is formed on the surface of the photosensitive drum 4, the electrostatic latent image on the surface of the photosensitive drum 4 is developed into a toner image, and the toner image on the surface of the photosensitive drum 4 is transferred to the intermediate transfer belt 5. As a result, a color toner image is formed on the intermediate transfer belt 5. This color toner image is secondarily transferred to the recording sheet P transported from the paper feed section 14 through the main transport path 8 in the nip area N between the intermediate transfer belt 5 and the secondary transfer roller 6.

[0017] Thereafter, the recording paper P is heated and pressed by the fixing device 15 to fix the toner image on the recording paper P by thermocompression, and the recording paper P is then discharged onto a paper discharge tray 17 via discharge rollers 16 .

[0018] Furthermore, when an image of the original M is to be recorded on the reverse side of the recording paper P, the recording paper P is transported to the discharge rollers 16 just before the discharge tray 17, the discharge rollers 16 are stopped once and then rotated in the reverse direction in a switchback transport, the recording paper P is returned to the main transport path 8 from the transport rollers 18 via the reversal transport path 9, the recording paper P is turned over, an image of the original M is formed on the reverse side of the recording paper P by the image forming unit 21, and the recording paper P is discharged to the discharge tray 17 via the discharge rollers 16.

[0019] Next, the image reading device 20 of this embodiment will be described. Fig. 2 is a cross-sectional view showing the image reading device 20 of this embodiment. Fig. 3 is a perspective view showing the appearance of the image reading device 20, showing a state in which the document transport unit 31 is open.

[0020] 2 and 3, the image reading device 20 includes a document transport unit 31 and a reading unit 32. The document transport unit 31 includes a document tray 33, a paper feed roller 34, a transport belt 35, a retard roller 36, a registration roller 37, a plurality of transport rollers 38, a first discharge roller 39, a first paper discharge tray 40, a contact image sensor (CIS) 42, a second discharge roller 48, and a second paper discharge tray 49.

[0021] The contact image sensor 42 corresponds to a second imaging section in the claims and will be referred to as the second imaging section 42 hereinafter.

[0022] In the document transport section 31, when a document M is placed on the document tray 33, the document M is pulled out of the document tray 33 by the paper feed roller 34, and the document M is guided between the transport belt 35 and the retard roller 36 to the linear transport path 45 and transported there.

[0023] A curved conveying path 46 is connected to a branching position BP in the middle of the straight conveying path 45. A switching claw 44 is provided at the branching position BP. The shaft at the left end of the switching claw 44 is rotated back and forth within a certain rotation range by an actuator (not shown), so that the tip of the switching claw 44 is directed diagonally upward or horizontally. When the tip of the switching claw 44 is directed diagonally upward, the document M is guided and conveyed from the straight conveying path 45 to the curved conveying path 46, and when the tip of the switching claw 44 is directed horizontally, the document M is conveyed through the entire straight conveying path 45.

[0024] In the linear transport path 45, the original M is transported from the resist roller 37 through between the second imaging section 42 and the shading roller 41 to the switching claw 44, and the original M is guided horizontally by the switching claw 44 and discharged to the second discharge tray 49 via the second discharge roller 48.

[0025] In addition, in the curved transport path 46, the original M that has been guided downward by the switching claw 44 is transported to the first platen glass 51, and the original M passes over the first platen glass 51 and is discharged to the first discharge tray 40 by the first discharge roller 39.

[0026] The reading section 32 includes a first platen glass 51, a second platen glass 52, a carriage 54, an optical system unit 55, a condenser lens 56, the CCD sensor 11, and the like.

[0027] The CCD sensor 11 corresponds to a first imaging section in the claims and will be referred to as the first imaging section 11 hereinafter.

[0028] In the reading section 32, the carriage 54 includes a light source 54A that irradiates light onto the document M, and a mirror 54B that reflects the light reflected by the document M. The optical system unit 55 also includes a mirror 55A and a mirror 55B. The mirror 55A receives the light reflected by the mirror 54B of the carriage 54 and redirects the light substantially vertically downward. The mirror 55B redirects the light reflected by the mirror 55A substantially horizontally and guides it to the first imaging section 11 via the condenser lens 56.

[0029] The carriage 54 and the optical system unit 55 are arranged to be movable back and forth along rails in a sub-scanning direction X perpendicular to the main scanning direction Y, and are moved in the sub-scanning direction X while maintaining a predetermined speed relationship by a known drive mechanism powered by a stepping motor (not shown).

[0030] Two hinges 58 are provided at a distance from one another at one end of the upper surface 32a of the reading unit 32, and these hinges 58 support the document transport unit 31 so that it can be opened and closed, allowing the user to open and close the document transport unit 31.

[0031] Here, the image reading device 20 has five types of reading modes for reading an image of the original M, namely, a stationary original reading mode, a first conveyed original single-sided reading mode, a second conveyed original single-sided reading mode, a first conveyed original double-sided reading mode, and a second conveyed original double-sided reading mode (the second conveyed original double-sided reading mode corresponds to the conveyed original double-sided reading mode in the claims). When a selection instruction for selecting one of these reading modes is accepted by the operation unit 23 (FIG. 6) through a user's operation, the image of the original M is read in the reading mode indicated by this selection instruction under the control of the control unit 29 (FIG. 6).

[0032] The stationary original reading mode is an operation for reading an image of the downward-facing surface (front surface, meaning the first surface; the same applies below for original M and in the claims) of original M placed on the second platen glass 52, and the first imaging section 11 of the reading unit 32 reads the image of the surface of original M through the second platen glass 52.

[0033] When the stationary document reading mode is selected, the document transport unit 31 is opened, and the document M is placed on the second platen glass 52 with its surface facing down while the second platen glass 52 of the reading unit 32 is open, and the document transport unit 31 is closed and the document M placed on the second platen glass 52 is pressed by the document transport unit 31. In the reading unit 32, the carriage 54 and the optical system unit 55 are moved in the sub-scanning direction X while maintaining a predetermined speed relationship, and the light of the light source 54A of the carriage 54 is irradiated onto the surface of the document M through the second platen glass 52, and the light reflected by the surface of the document M is reflected by the mirror 54B of the carriage 54. Furthermore, this light is reflected by the mirrors 55A and 55B of the optical system unit 55 and enters the first imaging unit 11 through the condenser lens 56. The first imaging unit 11 repeatedly reads the image of the surface of the document M in the main scanning direction Y (direction perpendicular to the sub-scanning direction X).

[0034] The first transported original single-sided reading mode is an operation for reading the image of the upward facing surface of the original M placed on the original tray 33 while transporting the original M, in which the original M is transported via the original tray 33 → straight transport path 45 → curved transport path 46 → first output tray 40, and the first imaging unit 11 of the reading unit 32 reads the image of the surface of the original M through the first platen glass 51.

[0035] 4, the document M is placed on the document tray 33 with its surface facing up while the document transport section 31 is closed, the document M is pulled out from the document tray 33 by the feed roller 34, the document M is transported through the straight transport path 45, the document M is guided by the switching claw 44 from the straight transport path 45 to the curved transport path 46 and transported, and the document M passes over the first platen glass 51 and is discharged to the first discharge tray 40. In the reading section 32, the carriage 54 and the optical system unit 55 are positioned at their respective predetermined positions below the first platen glass 51, the light of the light source 54A of the carriage 54 is irradiated onto the surface of the document M through the first platen glass 51, and the light reflected by the surface of the document M is reflected by the mirrors 54B, 55A, and 55B and made to enter the first imaging section 11 through the condenser lens 56, and the image of the surface of the document M is repeatedly read by the first imaging section 11 in the main scanning direction Y.

[0036] The second transported original one-sided reading mode is an operation for reading the image of the downward surface of the original M placed on the original tray 33 while transporting the original M, in which the original M is transported from the original tray 33 to the straight transport path 45 to the second output tray 49, and the second imaging unit 42 reads the image of the downward surface of the original M.

[0037] 5, with the document transport section 31 closed, the document M is placed on the document tray 33 with its surface facing down, the document M is pulled out from the document tray 33 by the feed roller 34, the document M is transported through the linear transport path 45, the document M passes over the second imaging section 42, the transport of the document M through the entire linear transport path 45 is maintained by the switching claw 44, and the document M is discharged to the second discharge tray 49. The second imaging section 42 repeatedly reads the image of the downward surface of the document M passing between the second imaging section 42 and the shading roller 41 in the main scanning direction Y.

[0038] The first transported original double-sided reading mode is an operation for reading images of both sides of an original M placed on the original tray 33 while the original M is being transported, in which the original M is transported from the original tray 33 to the straight transport path 45 to the curved transport path 46 to the first output tray 40, and the second imaging unit 42 reads an image of the downward-facing back side (reverse side, meaning the second side; the same applies below for original M) of the original M being transported through the straight transport path 45, and the first imaging unit 11 of the reading unit 32 reads an image of the front side of the original M through the first platen glass 51.

[0039] 4, with the document transport section 31 closed, the document M is placed on the document tray 33 with its front side facing up, the document M is pulled out from the document tray 33 by the feed roller 34, the document M is transported through the straight transport path 45, the document M passes over the second imaging section 42, the document M is guided by the switching claw 44 from the straight transport path 45 to the curved transport path 46 and transported, the document M passes over the first platen glass 51 and is discharged to the first discharge tray 40. The second imaging section 42 reads an image of the reverse side of the document M facing downward as it passes between the second imaging section 42 and the shading roller 41. In addition, in the reading unit 32, light from the light source 54A of the carriage 54 is irradiated onto the surface of the original M through the first platen glass 51, and the light reflected from the surface of the original M is reflected by each mirror 54B, 55A, 55B and made to enter the first imaging unit 11 through the focusing lens 56, causing the first imaging unit 11 to read the image of the surface of the original M.

[0040] The second transported original double-sided reading mode (corresponding to the transported original double-sided reading mode in the claims) is an operation of repeating the above-mentioned second transported original single-sided reading mode twice to read an image of the front side and an image of the back side of the original M placed on the original tray 33. In the second transported original double-sided reading mode, the original M placed on the original tray 33 is transported from the original tray 33 to the straight transport path 45 to the second discharge tray 49, and the second imaging unit 42 reads an image of the downward facing front side of the original M (first second transported original single-sided reading mode). After this, it is assumed that the user picks up the original M from the second discharge tray 49, turns the original M over, and places it again on the original tray 33. After this placement, the original M is transported again from the original tray 33 to the straight transport path 45 to the second discharge tray 49, and the second imaging unit 42 reads an image of the downward facing side of the original M as the back side (second second transported original single-sided reading mode).

[0041] The curved transport path 46 is suitable for transporting documents made of thin paper that bends flexibly and that are long in the transport direction. The straight transport path 45 is suitable for transporting documents that are difficult to bend and that are short in the transport direction, such as business cards and cards. Therefore, when reading an image of a document made of thin paper that bends flexibly and that is long in the transport direction, it is preferable to select the first transport document single-sided reading mode or the first transport document double-sided reading mode, and when reading an image of a document that is difficult to bend and that is short in the transport direction, such as business cards and cards, it is preferable to select the second transport document single-sided reading mode or the second transport document double-sided reading mode.

[0042] Fig. 6 is a block diagram showing the internal configuration of the image forming apparatus 10. As shown in Fig. 4, the image forming apparatus 10 includes an image reading device 20, an image forming section 21, an operation section 23, a display section 24, a touch panel 25, an image memory 26, a storage section 27, and a control unit 28. These components are capable of transmitting and receiving data or signals to and from each other via a bus.

[0043] The operation unit 23 includes physical keys such as a numeric keypad, a decision key, a start key, etc. The operation unit 23 receives various instructions based on the user's operation of the above keys. The display unit 24 is configured with a liquid crystal display (LCD: Liquid Crystal Display) or an organic light-emitting diode (OLED: Organic Light-Emitting Diode) display, etc.

[0044] A touch panel 25 is disposed on the screen of the display unit 24. The touch panel 25 is a so-called resistive film type or capacitive type touch panel, which detects contact (touch) of a user's finger or the like on the touch panel 25 together with the contact position, and outputs a detection signal indicating the coordinates of the contact position to a control unit 29 (described later) of the control unit 28. This touch panel 25 serves as an operation unit that accepts instructions based on a user's operation on the screen of the display unit 24.

[0045] The image memory 26 temporarily stores image data representing the image of the original M read by the first imaging unit 11 and the second imaging unit 42 of the image reading device 20.

[0046] The storage unit 27 is a large-capacity storage device such as a solid state drive (SSD) or a hard disk drive (HDD), and stores various application programs and various data.

[0047] The control unit 28 is composed of a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), etc. The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit), etc. The control unit 28 functions as a control unit 29 by the processor executing a control program stored in the ROM or the storage unit 27.

[0048] The control unit 29 comprehensively controls the image forming apparatus 10. The control unit 28 is connected to the image reading device 20, the image forming unit 21, the operation unit 23, the display unit 24, the touch panel 25, the image memory 26, and the storage unit 27. The control unit 29 controls the operation of these components and transmits and receives signals or data between these components.

[0049] The control unit 29 serves as a processing unit that executes various processes required for image formation by the image forming apparatus 10. The control unit 29 also accepts operation instructions input by the user based on a detection signal output from the touch panel 25 or an operation of a physical key of the operation unit 23. For example, the control unit 29 accepts a touch operation on a GUI (Graphical User Interface) or the like displayed on the screen of the display unit 24 through the touch panel 25. Furthermore, the control unit 29 has a function of controlling the display operation of the display unit 24.

[0050] The control unit 29 also controls motors, actuators, clutches, etc. for operating the paper feed roller 34, conveying belt 35, registration roller 37, each conveying roller 38, shading roller 41, first discharge roller 39, second discharge roller 48, switching claw 44, etc. in the document conveying unit 31 of the image reading device 20, and operates these to pull out the document M from the document tray 33 and convey it through a straight conveying path 45 or a curved conveying path 46.

[0051] In the image forming apparatus 10 configured as above, for example, a user operates the GUI displayed on the display unit 24 to select one of a stationary document reading mode, a first conveyed document single-sided reading mode, a second conveyed document single-sided reading mode, a first conveyed document double-sided reading mode, and a second conveyed document double-sided reading mode, and inputs a mode selection instruction to the operation unit 23 via the touch panel. Then, the user places the document M on the second platen glass 52 or the document tray 33, and operates the start key of the operation unit 23 to input an original reading instruction to the operation unit 23.

[0052] At this time, if the user inputs a mode selection instruction to select the stationary document reading mode, the user places the document M with its surface facing down on the second platen glass 52 of the image reading device 20, and if the first transported document single-sided reading mode is selected, the user places the document M with its surface facing up on the document tray 33.

[0053] Furthermore, when the user inputs a mode selection instruction to the operation unit 23 to select the second transported original single-sided reading mode, the document M is placed on the document tray 33 with its surface facing down. When the user inputs a mode selection instruction to the operation unit 23 to select the first transported original double-sided reading mode, the document M is placed on the document tray 33 with its surface facing up, similar to the first transported original single-sided reading mode. When the user inputs a mode selection instruction to the operation unit 23 to select the second transported original double-sided reading mode, the document M is placed on the document tray 33 with its surface facing down, similar to the second transported original single-sided reading mode.

[0054] When a mode selection instruction to select the stationary document reading mode is received by the operation unit 23, the control unit 29 controls the reading unit 32 to read the image of the surface of the document M on the second platen glass 52 using the first imaging unit 11 of the reading unit 32 as described above, stores image data representing the image of the surface of the document M in the image memory 26, inputs the image data representing the image of the surface of the document M from the image memory 26 to the image forming unit 21, and causes the image forming unit 21 to form the image of the surface of the document M represented by this image data on recording paper.

[0055] In addition, when a mode selection instruction to select the first transported original single-sided reading mode is received by the operation unit 23, the control unit 29 controls the original transport unit 31 to transport the original M along the path from the original tray 33 to the straight transport path 45 to the curved transport path 46 to the first output tray 40 as described above (see Figure 4), causes the first imaging unit 11 of the reading unit 32 to read the image of the front side of the original M through the first platen glass 51, stores image data representing the image of the front side of the original M in the image memory 26, inputs the image data representing the image of the front side of the original M from the image memory 26 to the image forming unit 21, and causes the image forming unit 21 to form the image of the front side of the original M represented by this image data on recording paper.

[0056] In addition, when a mode selection instruction to select the second transported original single-sided reading mode is received by the operation unit 23, the control unit 29 controls the original transport unit 31 to transport the original M along the path from the original tray 33 to the straight transport path 45 to the second output tray 49 as described above (see Figure 5), causes the second imaging unit 42 to read the image of the downward-facing front side of the original M, stores image data representing the image of the front side of the original M in the image memory 26, and causes the image forming unit 21 to form the image of the front side of the original M represented by this image data on the front and back of the recording paper.

[0057] In addition, when a mode selection instruction to select the first transported document double-sided reading mode is received by the operation unit 23, the control unit 29 controls the document transport unit 31, the second imaging unit 42, and the reading unit 32 to transport the document M along the path from the document tray 33 to the straight transport path 45 to the curved transport path 46 to the first discharge tray 40 as described above (see Figure 4), causes the second imaging unit 42 to read the image of the downward facing back side of the document M, causes the first imaging unit 11 of the reading unit 32 to read the image of the front side of the document M through the first platen glass 51, stores the image data representing the front and back sides of the document M in the image memory 26, inputs the image data representing the front and back sides of the document M from the image memory 26 to the image forming unit 21, and causes the image forming unit 21 to form the image of the front and back sides of the document M represented by these image data on the front and back sides of the recording paper.

[0058] In addition, when a mode selection instruction to select the second transported document double-sided reading mode is received by the operation unit 23, the control unit 29 controls the document transport unit 31 to transport the document M along the path from the document tray 33 to the straight transport path 45 to the second discharge tray 49 as described above (see Figure 5), and causes the second imaging unit 42 to read the image of the downward side of the document M as the front side (first second transported document single-sided reading mode), and stores image data showing the image of the front side of the document M in the image memory 26. Then, assuming that the user picks up the document M from the second discharge tray 49, turns it over and places it again on the document tray 33, after this placement, the control unit 29 transports the document M again along the path from the document tray 33 to the straight transport path 45 to the second discharge tray 49 (see FIG. 5), and causes the second imaging unit 42 to read the image of the face of the document M facing downward at this point as the back side (second second transported document single-sided reading mode), and stores image data representing the image of the back side of the document M in the image memory 26. The control unit 29 inputs the image data representing the image of the front side and the image of the back side of the document M from the image memory 26 to the image forming unit 21, and causes the image forming unit 21 to form the image of the front side and the image of the back side of the document M represented by these image data on the front and back sides of the recording paper.

[0059] Therefore, when the stationary document reading mode is selected, the user places the document M with its surface facing down on the second platen glass 52, the image of the surface of the document M is read by the first imaging unit 11, and the image of the surface of the document M is formed on recording paper by the image forming unit 21.

[0060] In addition, when the first transported document one-sided reading mode is selected, the user places the document M on the document tray 33 with its surface facing up, the first imaging unit 11 reads the image of the surface of the document M, and the image forming unit 21 forms the image of the surface of the document M on recording paper.

[0061] In addition, when the second transported original single-sided reading mode is selected, the user places the original M on the original tray 33 with its surface facing down, the second imaging unit 42 reads the image of the downward-facing surface of the original M, and the image of the surface of the original M is formed on recording paper by the image forming unit 21.

[0062] In addition, when the first transported document double-sided reading mode is selected, the user places document M on document tray 33 with its front side facing up, the second imaging unit 42 reads an image of the downward facing back side of document M, the first imaging unit 11 reads an image of the front side of document M, and the image forming unit 21 forms an image of the front side and an image of the back side of document M on the front and back of recording paper.

[0063] In addition, when the second transported original double-sided reading mode is selected, the user places the original M on the original tray 33 with its front side facing down, the second imaging unit 42 reads the image of the downward-facing front side of the original M a first time, and assuming that the user turns the original M over and places it again on the original tray 33, the second imaging unit 42 reads the image of the downward-facing side of the original M a second time, treating the downward-facing side as the back side, and the image forming unit 21 forms the images of the front side and back side of the original M on the front and back of the recording paper.

[0064] Here, when the user selects the first transported document double-sided reading mode, the user places the document M with its front side facing up on the document tray 33 of the image reading device 20, and when the user selects the second transported document double-sided reading mode, the user places the document M with its front side facing down on the document tray 33. However, the user may erroneously place the document M with its front side facing up on the document tray 33 despite selecting the second transported document double-sided reading mode.

[0065] In the event of an erroneous operation as described above, when the image data showing the front images and the image data showing the back images of multiple documents M are temporarily stored in image memory 26, and the image data showing the front images and the images showing the back images of each document M are read from image memory 26 and the front images and back images of each document M are associated with each other and displayed on display unit 24, the front images and back images of each document M are inadvertently reversed and swapped, which is an inconvenience. Also, the front images and back images of each document M are swapped, and the front and back sides of each recorded sheet are reversed.

[0066] In this embodiment, when the second transport document double-sided reading mode is executed, the control unit 29 causes the document transport unit 31 to sequentially pull out each document M from the document tray 33, causes the second imaging unit 42 to read the image of the downward side of each document M as one side, and stores the image data representing the image of one side of each document M in the image memory 26. Next, the control unit 29 assumes that each document M has been turned over and placed again on the document tray 33, causes the document transport unit 31 to sequentially pull out each document M from the document tray 33, causes the second imaging unit 42 to read the image of the downward side of each document M as the other side, and stores the image data representing the image of the other side of each document M in the image memory 26. Then, the control unit 29 reads the image data representing the image of one side of each document M and the image data representing the image of the other side of each document M from the image memory 26, and causes the display unit 24 to display the image of one side of each document M and the image of the other side of each document M in association with each other. Here, the control unit 29 causes the display unit 24 to display a message prompting the user to select whether the image on one side or the image on the other side of each document M should be the image on the front side. In accordance with instructions subsequently received by the operation unit 23, the control unit 29 sets either the image on one side or the image on the other side of each document M as the image on the front side, and sets the image on the other side as the image on the back side.

[0067] Thus, even if the image on the front side of each document M and the image on the back side of each document M are switched in a manner opposite to that expected after document reading in the second transport document double-sided reading mode, a correction can be made by switching the settings of the image on the front side of each document M and the image on the back side of each document M with a simple operation.

[0068] In addition, when reading documents in the second transport document double-sided reading mode, after the image data showing the images of one side of each document M is stored in the image memory 26 in the first reading, the image of the downward side of each document M is read again by the second imaging unit 42 in the second reading, and the image data showing the image of the downward side of each document M is stored in the image memory 26, the control unit 29 judges whether or not each image obtained in the first reading is the same as each image obtained in the second reading. At this time, in comparing each image obtained in the second reading with each image obtained in the first reading, the control unit 29 compares images of the same page, and if it judges that the images are the same on all pages, it judges that each image obtained in the first reading is the same as each image obtained in the second reading. When the control unit 29 judges that they are the same, it causes the display unit 24 to display a warning indicating that each document M placed on the document tray 33 at the time of the second reading was not inverted.

[0069] In addition, when determining whether the images obtained in the first reading and the images obtained in the second reading are identical, the control unit 29 may determine that the images obtained in the first reading are identical to the images obtained in the second reading if it determines that the images of the same page are identical for a predetermined number of pages for the images obtained in the first reading and the images obtained in the second reading.

[0070] Next, image processing when an original is read in the second conveyed original double-sided reading mode will be described below. Figures 7A, 7B, and 7C are flowcharts showing image processing when an original is read in the second conveyed original double-sided reading mode.

[0071] A user places multiple documents M on document tray 33, and the user operates operation unit 23 to receive a mode selection instruction for selecting the second transport document double-sided reading mode and an instruction to execute document reading.

[0072] The control unit 29 sets the image forming apparatus 10 to the second transported document double-sided reading mode in accordance with the mode selection instruction to select the second transported document double-sided reading mode (S101), and in response to the document reading execution instruction, controls the document transport unit 31 to transport the multiple documents M through the document tray 33 → linear transport path 45 → second discharge tray 49 (see FIG. 5), and causes the second imaging unit 42 to read the image of one side of each document M facing downward (S102). The control unit 29 stores image data indicating the image of one side of each document M in the image memory 26.

[0073] The control unit 29 determines whether or not the original M is on the original tray 33 based on an output signal obtained from a sensor (not shown) that detects the presence or absence of the original M on the original tray 33 (S103), and if it determines that the original M is present (S103 ``Present''), it repeats the processing of S102.

[0074] In addition, when the control unit 29 determines that the original M is not present based on the above output signal (S103 ``No''), it stops the original transport unit 31 from drawing out the original M from the original tray 33 and the second imaging unit 42 from reading the image of one side of the original M (S104).

[0075] As a result, image memory 26 stores image data representing images on one side of N (N=1, 2, 3, . . . ) sheets of originals M placed on original tray 33.

[0076] The control unit 29 causes the display unit 24 to display a message for the user, in this case a message urging the user to pick up the N sheets of the document M discharged to the second discharge tray 49, turn them over, place them again on the document tray 33, and input a document reading command (S105). For example, the display unit 24 displays a message E1 as shown in FIG.

[0077] The user sees the message E1, picks up the N sheets of originals M discharged onto the second discharge tray 49, turns them over, places them back on the original tray 33, and operates the start key.

[0078] In accordance with the document reading instruction received by the operation unit 23 in response to the operation of the start key, the control unit 29 starts drawing out the document M from the document tray 33 by the document transport unit 31 and reading the image of the other side of the document M by the second imaging unit 42, transports the Nth (N=1, 2, 3, ...)th document M through the document tray 33 → linear transport path 45 → second discharge tray 49 (see FIG. 5), and reads the image of the other side of the Nth document M facing downward by the second imaging unit 42 (S106). The control unit 29 stores image data showing the image of the other side of the Nth document M in the image memory 26.

[0079] Here, in the second transported document double-sided reading mode, as described above, it is assumed that the user will see the message E1 and, in the second document reading, will pick up the N documents M discharged to the second paper output tray 49, invert them, and place them again on the document tray 33 to have the documents read by the image reading device 20. However, despite seeing the message E1, the user may erroneously pick up the N documents M discharged to the second paper output tray 49 and place them again on the document tray 33 in the same orientation without inverting them, thereby having the documents read by the image reading device 20.

[0080] If such an erroneous operation occurs, in S106, the Nth original document M is transported from the original document tray 33 to the linear transport path 45 to the second discharge tray 49, and the image of one side of the Nth original document M facing downward is read again by the second imaging unit 42, and the image of the one side of the Nth original document M is read again and the image data is stored in the image memory 26.

[0081] Here, it is assumed that N sheets of originals M are placed on the original tray 33 with their front sides facing down, and that the N sheets of originals M are stacked on the original tray 33 in the order of the first page, the second page, the third page, ..., the Nth page from the bottom, with the Nth page of originals M stacked on top. In S102, an image on one side (front side) of the Nth page of originals M on the top is read first, and an image on one side (front side) of the 1st page of originals M on the bottom is read last. Then, the N sheets of originals M are stacked on the second discharge tray 49 from the bottom, going back from the Nth page to the 1st page, and the N sheets of originals M are sequentially discharged. Then, when the N sheets of originals M discharged to the second discharge tray 49 are turned over by the user and placed again on the original tray 33, the N sheets of originals M are placed on the original tray 33 with the other side (back side) opposite to the one side (front side) facing down, and in this state, the N sheets of originals M are again stacked from the bottom in the order of page 1, page 2, page 3, ..., page N, with the Nth page of originals M stacked on the top. Therefore, in S106, the image of the other side (back side) of the Nth page of originals M, which is the topmost page, is read first, and finally the image of the other side (back side) of the first page of originals M, which is the bottommost page, is read. 9(A), in the first reading, images of one side (front side) of N sheets of original M are read in sequence from page N back to page 1, and then, when the N sheets of original M are turned over and placed again on the original tray 33, images of the other side (back side) of N sheets of original M are read in sequence from page N back to page 1 in the second reading. The image memory 26 sequentially stores image data showing images of one side (front side) of N sheets of original M read in sequence from page N back to page 1, and then sequentially stores image data showing images of the other side (back side) of N sheets of original M read in sequence from page N back to page 1.

[0082] However, when the N sheets of the original M discharged to the second discharge tray 49 are placed again on the original tray 33 without being turned over, the N sheets of the original M are placed with their front faces down on the original tray 33, and the N sheets of the original M are stacked in the order of page N, page (N-1), page (N-2), ..., page 1, with the first page of the original M being stacked on top. Therefore, as shown in Fig. 9(B) , in the first reading, images of one side (front side) of the N sheets of the original M are read sequentially from page N back to page 1, and after the N sheets of the original M are placed again on the original tray 33 without being turned over, images of one side (front side) of the N sheets of the original M are read sequentially again from page 1 to page N in the second reading. The image memory 26 sequentially stores image data showing images of one side (front side) of N sheets of original document M read from the Nth page back to the 1st page, and then sequentially stores image data showing images of one side (front side) of N sheets of original document M read from the 1st page to the Nth page.

[0083] Also, if the user erroneously places N sheets of documents M with their surfaces facing up on the document tray 33 during the first document reading in which the front side of the document M should be read, even though the user wants to read the front side of the document M, the N sheets of documents M are stacked on the document tray 33 in the order of page N, page (N-1), page (N-3), ..., page 1 from the bottom, with the first page of document M stacked on top. In S102, first, an image of one side (back side) of the topmost first page of document M is read, and finally, an image of one side (back side) of the bottommost N page of document M is read, and the N sheets of documents M stacked from the bottom from page 1 to page N are sequentially discharged to the second discharge tray 49 (each document M has its front side facing up).

[0084] Then, when the N sheets of originals M discharged to the second discharge tray 49 are inverted and placed again on the original tray 33, the N sheets of originals M are placed with their front sides facing down on the original tray 33, and the N sheets of originals M are again stacked from the bottom in the order of page N, page (N-1), page (N-3), ..., page 1, with the 1st page of originals M stacked on top. Therefore, in S106, the image of the other side (front side) of the topmost 1st page of originals M is read first, and finally the image of the other side (front side) of the bottommost Nth page of originals M is read.

[0085] 10(A), images of one side (back side) of N sheets of original M are read in sequence from page 1 to page N in the first reading, and after the N sheets of original M are turned over and placed again on the original tray 33, images of the other side (front side) of N sheets of original M are read in sequence from page 1 to page N in the second reading. In the image memory 26, image data showing images of one side (back side) of N sheets of original M read from page 1 to page N is stored in sequence, and then image data showing images of the other side (front side) of N sheets of original M read from page 1 to page N is stored in sequence. The control unit 29 stores the reading order as a page order in association with the images of each original M obtained by the original reading by the image reading device 20.

[0086] However, during the first document reading in which the front side of the document M should be read, if the user erroneously places N documents M on the document tray 33 with their front sides facing up even though they want to read the front sides of the document M, and the N documents M discharged to the second output tray 49 are placed back on the document tray 33 without being turned over, the N documents M will be placed on the document tray 33 with their back sides facing down, and the N documents M will be stacked from the bottom up in the order of page 1, page 2, page 3, ..., page N, with the Nth page of document M stacked on top. 10(B), in the first reading, images of one side (back side) of N sheets of original M are read in sequence from page 1 to page N, and after N sheets of original M are placed again on original tray 33 without being turned over, in the second reading, images of one side (back side) of N sheets of original M are read again in sequence from page N back to page 1. Image memory 26 sequentially stores image data showing images of one side (back side) of N sheets of original M read from page 1 to page N, and then sequentially stores image data showing images of one side (back side) of N sheets of original M read from page N back to page 1.

[0087] 9B and 10B, if the N sheets of original M discharged to the second discharge tray 49 are placed on the original tray 33 again without being turned over in the second reading, the images of the two sides of the same page of the original M read in S102 and S106 will match, and the reading order of the N sheets of original M in S102 will be reversed to the reading order of the N sheets of original M in S106. For this reason, if the images of one side of the N sheets of original M read in S106 are selected in ascending order from the top of the reading order, and the images of one side of the N sheets of original M read in S102 are selected in descending order from the bottom, which is the opposite to the reading order, the images of the two sides of the original M on the same page are selected one by one, and when the images of one side of the original M on the same page are compared, these images will be the same as those read from the same side.

[0088] Furthermore, as is clear from Figures 9(A) and 10(A), even if the images of the other side of the N original documents M read in S106 are selected in ascending order from the top of the reading order and the images of one side of the N original documents M read in S102 are selected in descending order from the end, which is the opposite of the reading order, the two selected images will be different images obtained by reading one side and the other side, which is the opposite side.

[0089] Therefore, when the control unit 29 stores image data representing an image of one side or the other side of the document M in the image memory 26 in the reading in S106, it determines the reading order of the document M in ascending order from the top, selects the document M in descending order obtained by counting the determined reading order from the end from among the N documents M read in S102, reads out image data representing an image of one side of the selected document M from the image memory 26, compares the image data representing the images of the two documents M in the same ascending and descending order (S107), and determines whether the images of the two documents M are the same (S108). The determination of whether the images of the two documents M are the same is performed by a known method, for example, a technique such as pattern matching. For example, the control unit 29 calculates the difference between the two images, and determines that the images are the same if the difference is within a predetermined range (for example, 3%), and determines that the images are not the same if the difference is not within the predetermined range.

[0090] When the user picks up the N sheets of the document M discharged to the second discharge tray 49 as described above, turns them over, and places them again on the document tray 33, the images of the two documents M whose order is the same in ascending order and descending order as shown in FIG. 9(A) and FIG. 10(A) are not the same. The control unit 29 determines that the images of the two documents M are not the same (S108 "No"). Furthermore, the control unit 29 determines the presence or absence of the document M on the document tray 33 based on the detection output of the sensor that detects the presence or absence of the document M on the document tray 33 (S111), and when it determines that the document M is present (S111 "Present"), the process returns to S106. Also, when the control unit 29 determines that the document M is not present on the document tray 33 based on the detection output of the sensor (S111 "No"), it ends the drawing of the document M from the document tray 33 and the reading of the image of the other side of the document M by the second imaging unit 42 (S117).

[0091] Furthermore, if the user picks up the N sheets of originals M discharged to the second discharge tray 49 as described above and places them again on the original tray 33 without turning them over, the images on one side of two of the same page of originals M will be identical, as shown in Figures 9(B) and 10(B). The control unit 29 determines that the images on one side of two of the same page of originals M are identical (S108 "Yes"), counts up the number j of originals M whose images have been determined to be identical (the initial value of j is 0) (S109), and determines whether the number j has reached a preset threshold value J (J is an integer equal to or greater than 1) (S110). If the number j has not reached the threshold value J (S110 "No"), the control unit 29 determines whether or not there is an original M on the original tray 33 based on the detection output of a sensor that detects whether or not there is an original M on the original tray 33 (S111), and if it determines that there is an original M (S111 "Yes"), it returns to S106 and causes the original transport unit 31 to pull out the next original M from the original tray 33, causes the second imaging unit 42 to read the image of one side of the next original M again, and stores image data showing the image of one side of the next original M in the image memory 26 (S106).

[0092] The control unit 29 determines the reading order of the next original M in ascending order from the top, and selects the original M in descending order from the end of the N originals M read in S102, reads out image data showing the image of one side of this selected original M from the image memory 26, compares the image data showing the images of two originals M that match in ascending and descending order (S107), determines that the images of one side of two originals M on the same page are identical (S108 ``Yes''), counts up the number j of originals M (S109), and if the number j does not reach the threshold J (S110 ``No'') and it is determined that there is an original M on the original tray 33 (S111 ``Yes''), the process returns to S106.

[0093] Therefore, if the user places each document M on the document tray 33 again without turning it over, S106 to S109 are repeated as long as the documents M on the document tray 33 remain (S111 "Yes"), and it is determined that the number j has reached the threshold value J (S110 "Yes"). When the control unit 29 determines that the number j has reached the threshold value J, it stops drawing out the documents M from the document tray 33 and reading the image of one side of the documents M by the second imaging unit 42 (S112), and displays on the display unit 24 a warning message indicating that the documents M placed on the document tray 33 have not been turned over, and a message encouraging the user to turn the documents M over and place them on the document tray 33 again (S113). For example, on the screen of the display unit 24, two messages E2 and E3 as shown in FIG. 11 are displayed, and a read continuation key K11 (an example of a GUI) is also displayed.

[0094] After S113, the user looks at the messages E2 and E3, picks up each document M discharged to the second discharge tray 49, turns each document M over, places it back on the document tray 33, and operates the start key to input a document reading instruction to the operation unit 23.

[0095] For example, when the user turns each document M over and places it again on the document tray 33, and an instruction to re-read the documents is accepted by the operation unit 23 (S114 "Again"), the control unit 29 erases the image data indicating the images of one side of the j documents M read in S106 from the image memory 26 (S115), starts the document transport unit 31 to pull out the documents M from the document tray 33 and the second imaging unit 42 to read the images of the other side of the documents M again, and repeats the pulling out of the documents M from the document tray 33 and the reading of the images of the other side of the documents M by the second imaging unit 42 until the sensor detects that there are no documents M on the document tray 33 (S116), stores the image data indicating the images of the other sides of the N documents M on the document tray 33 in the image memory 26, and ends the pulling out of the documents M from the document tray 33 and the reading of the images of the other sides of the documents M by the second imaging unit 42 (S117).

[0096] On the other hand, after S113, if the user touches the continue reading key K11 on the screen of the display unit 24 to input a continuation instruction to continue reading of the currently read original M to the operation unit 23 even though it has been determined that the image on one side of the original M matches the image on the other side (114 "Continue"), the control unit 29, in accordance with the continuation instruction, causes the original transport unit 31 to pull out the original M from the original tray 33 without erasing from the image memory 26 the image data showing the image on the other side of the j pieces of original M read in S106. The process of pulling out the original M from the original tray 33 and the second imaging unit 42 reading the image of the other side of the original M is continued until the sensor detects that there is no original M on the original tray 33 (S118), and image data indicating the image of the other side of the remaining original M on the original tray 33 is stored in the image memory 26, and the process of pulling out the original M from the original tray 33 and the reading of the image of the other side of the original M by the second imaging unit 42 is completed (S117).

[0097] In addition, the control unit 29 repeats S106 to S109, and when it determines that there is no original M on the original tray 33 (S111 "No") without determining that the number j has reached the threshold J (S110 "No"), it ends the drawing of the original M from the original tray 33 and the reading of the image of the other side of the original M by the second imaging unit 42 (S117).

[0098] As a result, image data showing the image on the other side of each of the N sheets of documents M placed on the document tray 33 is stored in the image memory 26.

[0099] As a result, image memory 26 stores image data showing images on one side and image data showing images on the other side of N sheets of originals M as shown in FIG. 9(A) or FIG. 10(A).

[0100] The control unit 29 sequentially reads out image data showing images of one side of N sheets of original documents M stored in the image memory 26 in S102, and sequentially reads out image data showing images of the other side of N sheets of original documents M stored in the image memory 26 in S106, and matches the image data showing the image of one side with the image data showing the image of the other side for each page of original documents M (S119).

[0101] The control unit 29 judges whether one side of the document M is blank based on the image data showing the image on one side and the image data showing the image on the other side for each document M (S120), and if one side of the document M is blank (S120 "Yes"), it deletes the image data of the blank one side and leaves only the image data of the other side of the same page as image data showing the image of one page of the document M (S121). For example, the control unit 29 counts the number of white pixels in the image on one side of the document M, and judges that one side of the document M is blank if the ratio of the number of white pixels to the total number of all pixels constituting the image on one side is equal to or greater than a preset threshold value (e.g., 98%). The control unit 29 sets only the image data on the one side thus left as image data showing the image of one page of the document M as the front side of the page.

[0102] Moreover, if one side of the document M is not blank (S120 "No"), the control unit 29 does not perform S121.

[0103] Then, the control unit 29 causes the images of one side and the images of the other side of the N sheets of originals M associated in S119 to be displayed on the screen of the display unit 24 in the reverse order to the reading order of the N sheets of originals M (S122).

[0104] 12 or 13A, an image of one side and an image of the other side of N sheets of originals M are associated with each other and displayed on the screen of the display unit 24. Also, for originals M from which the image data of one blank side has been deleted, only the image of one side or the other side is displayed.

[0105] Also displayed on the screen of the display unit 24 are an OK key K21 and a batch swap key K22 (an example of a GUI) for accepting an instruction to collectively swap the front and back relationships of the images on one side and the images on the other side of N sheets of originals M. Furthermore, the control unit 29 causes the screen of the display unit 24 to display a message E4 urging the user to operate the OK key 21 if the images on the front and back sides of the originals M are not reversed, and urging the user to operate the batch swap key K21 if they are reversed.

[0106] Here, in the second transport document double-sided reading mode, before reading of the document M is started, the document M is placed on the document tray 33 with its front side facing down. In this case, as shown in Fig. 9(A), the image of the downward facing front side of the document M is read in the first time by the second imaging unit 42, the document M is turned over and placed again on the document tray 33, and the image of the downward facing back side of the document M is read in the second time by the second imaging unit 42. The reading order of the N sheets of the document M is page N, page (N-1), page (N-3), ..., page 1 in the first reading, and the reading order is also page N, page (N-1), page (N-3), ..., page 1 in the second reading. For this reason, as shown in the example of Figure 12, the control unit 29 displays on the screen of the display unit 24 the image of one side of the N sheets of original document M read in the first time by the second imaging unit 42 as the front image, and the image of the other side of the N sheets of original document M read in the second time by the second imaging unit 42 as the back image, and also displays the pages of the N sheets of original document M in the reversed reading order, i.e., page 1, page 2, page 3, ..., page N.

[0107] However, if an erroneous operation is performed such that original document M is placed on original document tray 33 with its front side facing up before the start of reading of original document M, an image of the downward-facing back side of original document M is read for the first time by second imaging unit 42, original document M is then turned over and placed again on original document tray 33, and an image of the downward-facing front side of original document M is read for the second time by second imaging unit 42, as shown in Fig. 10(A).In addition, the reading order of N original documents M is page 1, page 2, page 3, ..., page N in the first reading, and page 1, page 2, page 3, ..., page N in the second reading. For this reason, as shown in the example of Figure 13 (A), the control unit 29 causes the screen of the display unit 24 to display content in such a way that the image of one side of the N sheets of original document M read in the first time by the second imaging unit 42 becomes the image of the back side, and the image of the other side of the N sheets of original document M read in the second time by the second imaging unit 42 becomes the image of the front side, and the page order of the N sheets of original document M is page N, page (N-1), page (N-3), ..., page 1, which is the reverse of the reading order.

[0108] Then, when the user looks at the message E4 displayed on the screen of the display unit 24 and confirms that the image on one side of the original M read the first time is the image on the front side, and the image on the other side of the original M read the second time is the image on the back side, as shown in FIG. 12, the user touches the OK key K21 to input an acceptance instruction to the operation unit 23 to accept this.

[0109] In addition, when the user confirms that the image on one side of the original M read the first time becomes the image on the back side, and the image on the other side of the original M read the second time becomes the image on the front side, as shown in FIG. 13(A), the user touches the batch swap key K21 to input a batch swap instruction to the operation unit 23.

[0110] The control unit 29 waits for an acceptance instruction or a collective exchange instruction to be received by the operation unit 23 (S123), and when it detects the acceptance instruction (S123 "Accepted"), it maintains the front-back relationship between the image on one side of the document M read the first time and the image on the other side of the document M read the second time as shown in Fig. 12. After this, the process proceeds to S125.

[0111] In addition, when the control unit 29 detects receipt of a bulk swap instruction (S123 ``Swap''), it collectively swaps the image of one side (back side) of the N sheets of originals M read the first time with the image of the other side (front side) of the N sheets of originals M read the second time, as shown in Figure 13 (A), so that the image of the other side of the N sheets of originals M read the second time becomes the image of the front side, and the image of one side of the N sheets of originals M read the first time becomes the image of the back side, as shown in Figure 13 (B), and at the same time reverses the page order of each sheet of originals M (S124). Reversing the page order means either (i) changing the page order, which has been assigned in order from the minimum value (page 1) to the maximum value (page N), to one that starts from the maximum value (page N) to the minimum value (page 1), or (ii) changing the page order, which has been assigned in order from the maximum value (page N) to the minimum value (page 1), to one that starts from the minimum value (page 1) to the maximum value (page N). After this, the process proceeds to S125.

[0112] As a result, even if the user erroneously places the document M on the document tray 33 with its front side facing up before starting to read the document M, when in fact the document M should be placed on the document tray 33 with its front side facing down, it is possible to easily make the image on one side of the document M an image of the front side, and the image on the other side of the document M an image of the back side. The control unit 29 may store the image of the front side of each document M after the process of S124 in the memory unit 27 for storage.

[0113] After S124, or when "OK" is selected in S123, the control unit 29 causes the display unit 24 to display an editing screen H as shown in Fig. 14 (S125). In the editing screen H shown in Fig. 14, images of the front and back sides of N sheets of originals M are displayed in page order in a manner associated with each other, similar to Fig. 12 or Fig. 13(B). In addition, the editing screen H displays a page change key K31 for instructing to swap the pages of any two originals M, a group key K32 for instructing to combine multiple originals M into one group, an OK key 33, and an end key K34.

[0114] For example, the user touches the page change key K31, then touches the front image or back image of any document M, touches the front image or back image of another document M, and touches the OK key 33. When the control unit 29 detects these touch operations through the touch panel 25, it switches the page order of the front image and back image of any document M with the page order of the front image and back image of the other document M on the screen of the display unit 24 (S126).

[0115] Furthermore, the user touches the group key K32, and then touches either the front image or the back image of each of the multiple documents M, and touches the OK key 33. When the control unit 29 detects these touch operations through the touch panel 25, it groups each of the documents M whose front image or back image has been touched into one group, and sets a group that groups the front images and back images of the multiple documents M (S127).

[0116] Thereafter, when the user touches the end key K34, the control unit 29 detects the touch operation on the end key K34 through the touch panel 25, and generates one file for each group on the screen of the display unit 24 set in S127, in which image data showing the front and back images of the multiple documents M in the group are arranged in the page order of each document M, and stores this file in the storage unit 27, etc. The control unit 29 also stores image data showing the front and back images of other documents M that have not been grouped in the storage unit 27, etc. The control unit 29 also inputs the image data showing the front and back images of each document M from the image memory 26 to the image forming unit 21 in the page order of each document M, and causes the image forming unit 21 to form the front and back images of each document M on the front and back of each recording paper (S128).

[0117] In this manner, in this embodiment, an image of one side and an image of the other side of each document M are displayed on the display unit 24, and an option of selecting either the image of one side or the image of the other side of each document M as the image on the front side is displayed on the display unit 24, and either the image of one side or the image of the other side of each document M is selected as the image on the front side depending on the user's instructions. Therefore, even if the image on the front side of each document M and the image on the back side of each document M are swapped, this can be easily corrected.

[0118] Furthermore, when each original M is placed again on the original tray 33 without being turned over, and the image of one side of each original M is read again by the second imaging unit 42, and it is determined that the images of one side of each original M read twice are identical, a warning message or the like indicating that the front and back of each original M placed on the original tray M have not been turned over is displayed on the display unit 24, thereby quickly preventing the image of one side of each original M from being read twice repeatedly.

[0119] In the above embodiment, when the number j of sheets of the original M, which are determined to have the same images on one side of the original M read twice, reaches the threshold value J, each original M is deemed to be placed on the original tray 33 again without being turned over. Alternatively, when the images of all the originals M on the original tray 33 are determined to have the same images on one side of the originals M read twice, each original M may be deemed to be placed on the original tray 33 again without being turned over. In this case, the control unit 29 also causes the display unit 24 to display a warning message indicating that the originals M placed on the original tray 33 have not been turned over, and a message urging the user to turn the originals M over and place them on the original tray 33 again.

[0120] Moreover, the configurations and processes of the above-described embodiment described with reference to FIGS. 1 to 14 are merely examples of the present invention, and the present invention is not limited to these configurations and processes. [Explanation of symbols]

[0121] 10 Image forming device 20 Image reader 21 Image forming section 23 Control section 24 Display 25 Touch Panel 26 Image Memory 27 Memory section 28 Control Unit 29 Control Unit 31 Document transport section 32 Reading unit 11 CCD sensor (first imaging section) 40 First output tray 42 CIS (second imaging unit) 45 Straight conveyor path 46 Curved conveyor path 49 Second output tray

Claims

1. A display unit; a document tray on which a plurality of documents are placed; a linear transport path for transporting the plurality of documents drawn from the document tray; a curved conveying path branched off from the straight conveying path; a first imaging unit that reads images of the surfaces of a plurality of documents facing upward on the document tray while the plurality of documents are being transported through the curved transport path; a second imaging unit that is provided upstream of a branching position of the straight conveying path and the curved conveying path in a document conveying direction and that reads images of the faces of the documents that face downward on the document tray while the documents are being conveyed through the straight conveying path; a memory that temporarily stores images read by the first imaging unit and the second imaging unit; An operation unit that receives instructions from a user; a control unit that performs operation control in a transported document double-sided reading mode, which causes the multiple documents pulled out from the document tray to be transported through the linear transport path, causes the second imaging unit to read images of the faces of the multiple documents that face downward on the document tray, and subsequently, when the multiple documents are placed back on the document tray, causes the multiple documents pulled out from the document tray to be transported through the linear transport path, and causes the second imaging unit to read images of the faces of the multiple documents that face downward on the document tray, When an instruction to execute the double-sided reading mode is received from the operation unit, the control unit controls operation in the double-sided reading mode of the transported document, causes the display unit to display each image obtained in the first reading by the second imaging unit and each image obtained in the second reading by the second imaging unit, and, in accordance with the instructions received from the operation unit, sets either the images obtained in the first reading or the images obtained in the second reading as the front image collectively, and sets the other as the back image collectively.

2. The control unit determines whether each image obtained by reading with the second imaging unit is a blank image obtained by reading a blank page, and among the images obtained by reading with the second imaging unit, does not store an image determined to be a blank image in the memory, and for each image obtained in the first reading and each image obtained in the second reading, sets an image on the same page as the image determined to be a blank image but is not a blank image on the front side of the page.

3. The image reading device of claim 1, wherein the control unit determines whether each image obtained in the first reading and each image obtained in the second reading are identical, and when it is determined that they are identical, causes the display unit to display a warning indicating that the document placed on the document tray was not inverted during the second reading by the second imaging unit.

4. The image reading device of claim 3, wherein, in determining whether the images obtained in the first reading and the images obtained in the second reading are identical, the control unit determines that the images obtained in the first reading and the images obtained in the second reading are identical if it determines that the images on all pages are identical, or if it determines that a predetermined number of images on the same page are identical.

5. 5. The image reading device of claim 3, wherein the control unit, after displaying the warning on the display unit, when the control unit causes the second imaging unit to read images of the surfaces of the multiple documents that are facing downward on the document tray for the third time in accordance with instructions received from the operation unit, swaps the images obtained in the second reading with the images obtained in the third reading, causes the images obtained in the first reading and the images obtained in the third reading to be displayed on the display unit, and, in accordance with the instructions received from the operation unit, sets either the images obtained in the first reading or the images obtained in the third reading as the front side images collectively, and sets the other as the back side images collectively.

6. The image reading device of claim 1, wherein the control unit reads out images of one side and the other side of each of the documents from the memory, associates them, and displays them on the display unit, and changes the order of the images of one side and the other side of each of the documents while maintaining the association in accordance with instructions received from the operation unit.

7. The image reading device of claim 1, wherein the control unit reads out images of one side and the other side of each of the documents from the memory, associates them, and displays them on the display unit, and in response to instructions from operating the operation unit, groups the images of one side and the other side of at least one of the documents while maintaining the association and stores them in a single file.

8. The image reading device according to claim 1 ; an image forming section that forms an image of the document read by the image reading device on a recording sheet;

Images