Image forming device

Abstract

To provide an image formation apparatus capable of suppressing erroneous determination that double feeding occurs even though the double feeding does not occur by determining whether plain paper, thick paper, or thin paper is transported and the double feeding occurs.SOLUTION: A transmission unit 50 transmits a transmission ultrasonic wave having a predetermined sound volume. A reflection ultrasonic wave reception unit 52 receives a reflection ultrasonic wave in which the transmission ultrasonic wave reflects on a sheet. A transparent ultrasonic wave reception unit 54 receives a transparent ultrasonic wave transmitting the sheet. A sound volume detection unit 60 detects reflection sound volumes (P1, P2, P3) of the reflection ultrasonic waves, and detects transparent sound volumes (Q1, Q2, Q3) of the transparent ultrasonic waves. A determination unit 80 determines a thickness of the sheet transported by a transportation unit 32 and determines whether the sheet is double-fed, based on a comparison result of the reflection sound volumes (P1, P2, P3) with a reference reflection sound volume P2 and a comparison result of the transparent sound volumes (Q1, Q2, A3) with a reference transparent sound volume Q2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Patent Document 1 discloses an image reading device that prevents paper jams from occurring in the transport path by independently arranging a sensor for detecting thick paper and a sensor for detecting double feed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-161292 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, a pair of a transmitter and a receiver are arranged facing each other across the document transport path. Therefore, it is sometimes impossible to distinguish between normal transport of a single document of normal thickness and multiple feeding of thin documents. Also, it is sometimes impossible to distinguish between multiple feeding of normal thickness documents and normal transport of a single thick document.

[0005] To provide an image forming device capable of suppressing erroneous determination that double feeding has occurred when it has not actually occurred, by determining whether plain paper, thick paper, or thin paper is being conveyed, or whether double feeding has occurred. [Means for solving the problem]

[0006] The image forming apparatus according to the present invention includes a feeding section, a transport section, a transmitting section, a reflected ultrasonic wave receiving section, a transmitted ultrasonic wave receiving section, a volume detecting section, and a discrimination section. The feeding section feeds a sheet. The transport section transports the sheet. The transmitting section transmits a transmitted ultrasonic wave of a predetermined volume. The reflected ultrasonic wave receiving section receives a reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet. The transmitted ultrasonic wave receiving section receives a transmitted ultrasonic wave that is the transmitted ultrasonic wave transmitted through the sheet. The volume detecting section detects the reflected volume of the reflected ultrasonic wave and outputs reflected volume information, and detects the transmitted volume of the transmitted ultrasonic wave and outputs transmitted volume information. The discrimination section discriminates the thickness of the sheet being transported through the transport section and discriminates whether the sheet is being fed in duplicate based on a comparison result between the reflected volume indicated by the reflected volume information and a reference reflected volume and a comparison result between the transmitted volume indicated by the transmitted volume information and a reference transmitted volume. Effect of the Invention

[0007] According to the image forming device of the present invention, it is possible to determine whether plain paper, thick paper, or thin paper is being transported, or whether a double feed has occurred, thereby preventing a false determination that a double feed has occurred when a double feed has not actually occurred.

[0008] Furthermore, according to the image forming device of the present invention, it is possible to determine whether thick paper is being transported or whether a double feed has occurred, thereby preventing the misdetermination that a double feed has occurred even when the thick paper is being transported normally. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a block diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention; [Diagram 3] 1 is a diagram illustrating a simplified configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 4] 1A to 1D are diagrams showing the relationship between a transmitted ultrasonic wave, a reflected ultrasonic wave, and a transmitted ultrasonic wave. [Diagram 5] FIG. 4 is a diagram illustrating a table stored in a storage unit. [Figure 6] 5 is a flowchart showing information processing performed by the image forming apparatus according to the present embodiment. [Figure 7] 5 is a flowchart showing information processing performed by the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0011] First, an image forming apparatus 10 will be described with reference to Fig. 1. Fig. 1 is a diagram showing an image forming apparatus 10 according to an embodiment of the present invention.

[0012] 1, an image forming apparatus 10 includes a reading unit 11, an operation unit 13, and an image forming unit 16. Specific examples of the image forming apparatus 10 include a printer, a fax machine, and a multifunction peripheral.

[0013] The reading unit 11 includes an auto document feeder (ADF) and a scanner.

[0014] The reading unit 11 further has a feed tray 12. An original (sheet) (not shown) placed on the feed tray 12 is transported to an original reading surface (not shown) by a transport mechanism (not shown) of the reading unit 11, read by the reading unit (not shown), and converted into image data.

[0015] The operation unit 13 includes a display unit 14 and an input unit 15 .

[0016] The operation unit 13 accepts operations from the user.

[0017] The display unit 14 displays information to the user, or outputs information input by the user to the control unit 20 described in FIG. 2. The display unit 14 includes a display such as an LCD (Liquid Crystal Display) and displays various images. The display may have a touch panel function and include a touch sensor. The display with the touch panel function constitutes a part of the input unit 15. The input unit 15 may include a plurality of hardware buttons that can input information.

[0018] Numbers, symbols, etc. are provided on the input unit 15. A user can operate the input unit 15 to input numbers, symbols, etc.

[0019] The user can operate the display unit 14 to, for example, give an image formation instruction, set an image formation setting, give a data transmission / reception instruction, set a data transmission / reception setting, give an image reading instruction, and set an image reading setting.

[0020] The image forming section 16 includes a feeding section 17 and a discharging section 18 .

[0021] Inside image forming unit 16, a printing mechanism (not shown), such as a feeding mechanism, a transport mechanism, an image forming mechanism, or a discharge mechanism, is disposed.

[0022] The feed section 17 can be pulled out from the image forming section 16, and a sheet (not shown) placed on the feed section 17 is fed by a feed mechanism and a transport mechanism.

[0023] For example, in the case of an electrophotographic system, an image is formed on a sheet fed by a feeding mechanism with colorants and color materials such as toner by a charging mechanism, an exposure mechanism, a developing mechanism, and a transfer mechanism of the image forming unit 16, and the sheet is conveyed to a discharge mechanism. For example, in the case of an inkjet system, an image is formed on a sheet by an ink cartridge and an ink head of the image forming unit 16 with colorants and color materials such as ink, and the sheet is conveyed to a discharge mechanism.

[0024] The sheet is discharged to a discharge section 18 by a discharge mechanism.

[0025] Next, a specific embodiment of the image forming apparatus 10 according to the present embodiment will be described with reference to FIGS. 2 to 5 in addition to FIG.

[0026] Fig. 2 is a block diagram showing the configuration of the image forming apparatus 10 according to the present embodiment. Fig. 3 is a diagram showing a simplified configuration of the image forming apparatus 10 according to the present embodiment. Fig. 2 may show a conveying mechanism in the image forming unit 16 of the image forming apparatus 10. Fig. 2 may show a conveying mechanism in the reading unit 11 of the image forming apparatus 10.

[0027] 4(a) to 4(d) are diagrams showing the relationship between the transmitted ultrasonic wave and the reflected ultrasonic wave and the transmitted ultrasonic wave. FIG. 5 is a diagram showing a table stored in the storage unit .

[0028] The image forming apparatus 10 according to this embodiment includes a feed section 17, a transport section 32, a transmission section 50, a reflected ultrasonic wave receiving section 52, a transmitted ultrasonic wave receiving section 54, a volume detection section 60, and a discrimination section 80. The feed section 17 feeds a sheet. The transport section 32 transports a sheet. The transmission section 50 transmits a transmitted ultrasonic wave at a predetermined volume. The reflected ultrasonic wave receiving section 52 receives a reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet. The transmitted ultrasonic wave receiving section 54 receives a transmitted ultrasonic wave that is the transmitted ultrasonic wave transmitted by the sheet. The volume detection section 60 detects the reflected volume (P1, P2, P3) of the reflected ultrasonic wave and outputs reflected volume information, and detects the transmitted volume (Q1, Q2, Q3) of the transmitted ultrasonic wave and outputs transmitted volume information. The discrimination unit 80 discriminates the thickness of the sheet being conveyed by the conveying unit 32 and determines whether or not the sheets are being fed in duplicate based on the comparison result between the reflected volume (P1, P2, P3) indicated by the reflected volume information and the reference reflected volume P2, and the comparison result between the transmitted volume (Q1, Q2, Q3) indicated by the transmitted volume information and the reference transmitted volume Q2.

[0029] The control unit 20, driving unit 22, transmission unit 50, reflected ultrasound receiving unit 52, transmitted ultrasound receiving unit 54, volume detection unit 60, memory unit 70, and discrimination unit 80 shown in Figure 2 are realized, as an example, by an ASIC (Application Specific Integrated Circuit).

[0030] The transmission unit 50, the reflected ultrasound receiving unit 52, and the transmitted ultrasound receiving unit 54 are realized, for example, by a CODEC (Coder / Decoder).

[0031] The control unit 20 shown in FIG.

[0032] The driving unit 22 drives the image forming unit 16 and the reading unit 11 in accordance with instructions from the control unit 20. When driving the image forming unit 16 and the reading unit 11, the driving unit 22 drives the pick-up roller 30 and the conveying unit 32.

[0033] The feeding section 17 feeds the sheets stored in the feeding tray 12 .

[0034] The pickup roller 30 picks up a sheet from the feeding tray 12 of the feeding section 17 and conveys the sheet toward the conveying section 32 .

[0035] The conveying unit 32 conveys the sheet. The conveying unit 32 may include a conveying roller and a retard roller. The retard roller adjusts the timing of conveying the sheet.

[0036] The control unit 20 controls the transmission unit 50 .

[0037] The control unit 20 includes a processor such as a central processing unit (CPU) and a graphics processing unit (GPU). The control unit 20 may be an integrated circuit such as a system-on-a-chip (SoC) in which other components are integrated.

[0038] Specifically, the control unit 20 refers to the data stored in the storage unit 70 as necessary. The control unit 20 executes instructions included in the program stored in the storage unit 70 and controls each component to realize various functions.

[0039] The transmitting unit 50 transmits ultrasonic waves at a predetermined volume P in accordance with an instruction from the control unit 20 .

[0040] The reflected ultrasonic wave receiving unit 52 receives the reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet. The reflected volume (P1, P2, P3) of the reflected ultrasonic wave changes depending on the thickness of the sheet. The reflected volume (P1, P2, P3) of the reflected ultrasonic wave changes depending on whether the sheets are being fed in a double-feed state or not.

[0041] The volume detection unit 60 detects the reflected volumes (P1, P2, P3) of the reflected ultrasonic waves, and outputs reflected volume information.

[0042] The transmitted ultrasonic wave receiving unit 54 receives the transmitted ultrasonic wave that is transmitted through the sheet. The transmitted volume (Q1, Q2, Q3) of the transmitted ultrasonic wave changes depending on the thickness of the sheet. The transmitted volume (Q1, Q2, Q3) of the transmitted ultrasonic wave changes depending on whether the sheets are being fed in a double-feed state or not.

[0043] The sheet may be a document on which an image is formed. In this embodiment, the sheet includes plain paper, thick paper, or thin paper. A specific example of plain paper is copy paper. An example of the thickness of plain paper is 0.09 mm. A specific example of thick paper is postcard paper. An example of the thickness of thick paper is greater than 0.09 mm. An example of the thickness of thin paper is less than 0.09 mm. A specific example of thin paper is newspaper.

[0044] The volume detector 60 detects the transmitted volume (Q1, Q2, Q3) of the transmitted ultrasound, and outputs transmitted volume information.

[0045] The storage unit 70 stores the reference reflected sound volume P2 and the reference transmitted sound volume Q2.

[0046] The discrimination unit 80 discriminates the thickness of the sheet being conveyed by the conveying unit 32 and determines whether or not the sheets are being fed in duplicate based on the comparison result between the reflected volume (P1, P2, P3) indicated by the reflected volume information and the reference reflected volume P2, and the comparison result between the transmitted volume (Q1, Q2, Q3) indicated by the transmitted volume information and the reference transmitted volume Q2.

[0047] In this embodiment, the reflected sound volume P1 is greater than the reference reflected sound volume P2. The reflected sound volume P3 is less than the reference reflected sound volume P2. The transmitted sound volume Q1 is greater than the reference transmitted sound volume Q2. The transmitted sound volume Q3 is less than the reference transmitted sound volume Q2.

[0048] As shown in Figures 4(a) and 5, when plain paper is transported along the transport path 34, the reflected ultrasound receiving unit 52 receives reflected ultrasound with a reflected volume P2 equal to the reference reflected volume P2, and the transmitted ultrasound receiving unit 54 receives transmitted ultrasound with a transmitted volume Q2 equal to the reference transmitted volume Q2.

[0049] As shown in Figures 4(b) and 5, when cardboard is transported along the transport path 34, the reflected ultrasound receiving unit 52 receives reflected ultrasound with a reflected volume P1 that is greater than the reference reflected volume P2, and the transmitted ultrasound receiving unit 54 receives transmitted ultrasound with a transmitted volume Q3 that is smaller than the reference transmitted volume Q2.

[0050] As shown in Figures 4(c) and 5, when thin paper is transported along the transport path 34, the reflected ultrasound receiving unit 52 receives reflected ultrasound with a reflected volume P3 that is smaller than the reference reflected volume P2, and the transmitted ultrasound receiving unit 54 receives transmitted ultrasound with a transmitted volume Q1 that is larger than the reference transmitted volume Q2.

[0051] As shown in Figures 4(c) and 5, when sheets are being fed in multiple passes through the conveying path 34, the reflected ultrasound receiving unit 52 receives reflected ultrasound with a reflected volume P3 that is smaller than the reference reflected volume P2, and the transmitted ultrasound receiving unit 54 receives transmitted ultrasound with a transmitted volume Q3 that is smaller than the reference transmitted volume Q2.

[0052] The control unit 20 controls the drive unit 22 to drive or stop driving based on the discrimination information.

[0053] The driving unit 22 drives the image forming unit 16 or the reading unit 11, or stops driving the same.

[0054] The image forming unit 16 forms an image on a sheet.

[0055] The reading unit 11 reads an image written on a sheet (original).

[0056] The discharge section 18 discharges the sheet (original).

[0057] According to the image forming device 10 of this embodiment, it is possible to determine whether plain paper, thick paper, or thin paper is being transported, or whether a double feed has occurred, thereby preventing erroneous determination that a double feed has occurred when a double feed is not actually occurring.

[0058] Furthermore, according to the image forming device 10 of this embodiment, it is possible to determine whether thick paper is being transported or whether a double feed has occurred, thereby preventing the misdetermination that a double feed has occurred even when the thick paper is being transported normally.

[0059] Next, referring to Fig. 1 to Fig. 3, and further Fig. 4(a) and Fig. 5, an embodiment in which plain paper is transported on the transport path 34 will be described in more detail. Fig. 4(a) is a diagram showing the relationship between the transmitted ultrasonic wave, the reflected ultrasonic wave, and the transmitted ultrasonic wave. Fig. 5 is a diagram showing a table stored in the storage unit 70.

[0060] In the image forming device 10 of this embodiment, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is plain paper and that the sheets are not being fed in duplicate, based on a comparison result indicating that the reflected volume P2 indicated by the reflected volume information is equal to the reference reflected volume P2 and a comparison result indicating that the transmitted volume Q2 indicated by the transmitted volume information is equal to the reference transmitted volume Q2.

[0061] In this embodiment, the process is the same as in the previous embodiment up to the point where the transmitting unit 50 transmits ultrasonic waves at a predetermined volume P in accordance with an instruction from the control unit 20, so a duplicated description will be omitted.

[0062] As shown in FIGS. 2 and 3, the reflected ultrasonic wave receiving unit 52 receives the reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet.

[0063] The volume detection unit 60 detects the reflected volume P2 of the reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet, and outputs the reflected volume information. When the sheet transported by the transport unit 32 is plain paper, the reflected volume P2 of the reflected ultrasonic wave is substantially the same as the reference reflected volume P2, as shown in Fig. 4(a) and Fig. 5. The volume detection unit 60 detects that the reflected ultrasonic wave receiving unit 52 has received the reflected volume P2, and outputs the transmitted volume information.

[0064] The transmitted ultrasonic wave receiving unit 54 receives transmitted ultrasonic waves that are the result of the transmitted ultrasonic waves passing through the sheet.

[0065] The volume detection unit 60 detects the transmitted volume Q2 of the transmitted ultrasonic wave that has passed through the sheet, and outputs the transmitted volume information. When the sheet transported by the transport unit 32 is plain paper, the transmitted volume Q2 of the transmitted ultrasonic wave is the reference transmitted volume Q2, as shown in Figures 4(a) and 5. The volume detection unit 60 detects that the transmitted ultrasonic wave receiving unit 54 has received the transmitted volume Q2, and outputs the transmitted volume information.

[0066] The storage unit 70 stores the reference transmitted sound volume Q2 and the reference reflected sound volume P2.

[0067] Based on the comparison result between the reflected volume P2 indicated by the reflected volume information and the reference reflected volume P2, and the comparison result between the transmitted volume Q2 indicated by the transmitted volume information and the reference transmitted volume Q2, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is plain paper and that the sheets are not being transported in duplicate.

[0068] In other words, based on the comparison result indicating that the reflected volume P2 indicated by the reflected volume information is equal to the reference reflected volume P2 and the comparison result indicating that the transmitted volume Q2 indicated by the transmitted volume information is equal to the reference transmitted volume Q2, it is determined that the sheet being transported by the transport unit 32 is plain paper and that the sheets are not being transported in duplicate.

[0069] The control unit 20 controls the drive unit 22 based on the discrimination information.

[0070] The driving unit 22 drives the image forming unit 16 or the reading unit 11 .

[0071] The image forming unit 16 forms an image on a sheet.

[0072] The reading unit 11 reads an image written on a sheet (original).

[0073] The discharge section 18 discharges the sheet (original).

[0074] According to the image forming device 10 of this embodiment, it is possible to determine whether plain paper is being transported or whether a double feed has occurred, thereby preventing a mistaken determination that a double feed has occurred when a double feed has not actually occurred.

[0075] Furthermore, according to the image forming device 10 of this embodiment, it is possible to determine whether plain paper is being transported or whether a double feed has occurred, thereby preventing the misdetermination that a double feed has occurred even when plain paper is being transported normally.

[0076] Next, with reference to Figs. 1 to 3, and further to Figs. 4(b) and 5, an embodiment in which cardboard is transported along the transport path 34 will be described.

[0077] In the image forming device 10 of this embodiment, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is cardboard and that the sheets are not being fed in duplicate, based on a comparison result indicating that the reflected volume P1 indicated by the reflected volume information is greater than the reference reflected volume P2 and a comparison result indicating that the transmitted volume Q3 indicated by the transmitted volume information is smaller than the reference transmitted volume Q2.

[0078] In this embodiment, the process is the same as in the previous embodiment up to the point where the transmitting unit 50 transmits ultrasonic waves at a predetermined volume P in accordance with an instruction from the control unit 20, so a duplicated description will be omitted.

[0079] As shown in FIGS. 2 and 3, the reflected ultrasonic wave receiving unit 52 receives the reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet.

[0080] When the sheet transported by the transport unit 32 is cardboard, the reflected volume P1 of the reflected ultrasonic wave is greater than the reference reflected volume P2, as shown in Fig. 4(b) and Fig. 5. The volume detection unit 60 detects that the reflected ultrasonic wave receiving unit 52 has received the reflected volume P1, and outputs transmitted volume information.

[0081] The transmitted ultrasonic wave receiving unit 54 receives transmitted ultrasonic waves that are the result of the transmitted ultrasonic waves passing through the sheet.

[0082] When the sheet transported by the transport unit 32 is thick paper, the transmitted volume Q3 of the transmitted ultrasonic wave is smaller than the reference transmitted volume Q2, as shown in Fig. 4(b) and Fig. 5. The volume detection unit 60 detects that the transmitted ultrasonic wave receiving unit 54 has received the transmitted volume Q3, and outputs the transmitted volume information.

[0083] The storage unit 70 stores the reference reflected sound volume P2 and the reference transmitted sound volume Q2.

[0084] Based on the comparison result between the reflected volume P1 indicated by the reflected volume information and the reference reflected volume P2, and the comparison result between the transmitted volume Q3 indicated by the transmitted volume information and the reference transmitted volume Q2, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is cardboard and that the sheets are not being transported in duplicate.

[0085] In other words, based on the comparison result indicating that the reflected volume P1 indicated by the reflected volume information is greater than the reference reflected volume P2 and the comparison result indicating that the transmitted volume Q3 indicated by the transmitted volume information is smaller than the reference transmitted volume Q2, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is cardboard and that the sheets are not being transported in duplicate.

[0086] The control unit 20 controls the drive unit 22 based on the discrimination information.

[0087] The driving unit 22 drives the image forming unit 16 or the reading unit 11 .

[0088] The image forming unit 16 forms an image on a sheet.

[0089] The reading unit 11 reads an image written on a sheet (original).

[0090] The discharge section 18 discharges the sheet (original).

[0091] According to the image forming device 10 of this embodiment, it is possible to determine whether thick paper is being transported or whether a double feed has occurred, thereby preventing erroneous determination that a double feed has occurred when a double feed has not actually occurred.

[0092] Furthermore, according to the image forming device 10 of this embodiment, it is possible to determine whether thick paper is being transported or whether a double feed has occurred, thereby preventing the misdetermination that a double feed has occurred even when the thick paper is being transported normally.

[0093] Next, with reference to Figs. 1 to 3, and further to Figs. 4(c) and 5, an embodiment in which thin paper is transported along the transport path 34 will be described.

[0094] In the image forming device 10 of this embodiment, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is thin paper and that the sheets are not being fed in duplicate, based on a comparison result indicating that the reflected volume P3 indicated by the reflected volume information is smaller than the reference reflected volume P2 and a comparison result indicating that the transmitted volume Q3 indicated by the transmitted volume information is larger than the reference transmitted volume Q2.

[0095] In this embodiment, the process is the same as in the previous embodiment up to the point where the transmitting unit 50 transmits ultrasonic waves at a predetermined volume P in accordance with an instruction from the control unit 20, so a duplicated description will be omitted.

[0096] As shown in FIGS. 2 and 3, the reflected ultrasonic wave receiving unit 52 receives the reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet.

[0097] When the sheet transported by the transport unit 32 is thin paper, the reflected volume P3 of the reflected ultrasonic wave is smaller than the reference reflected volume P2, as shown in Figures 4(c) and 5. The volume detection unit 60 detects that the reflected ultrasonic wave receiving unit 52 has received the reflected volume P3, and outputs transmitted volume information.

[0098] The transmitted ultrasonic wave receiving unit 54 receives transmitted ultrasonic waves that are the result of the transmitted ultrasonic waves passing through the sheet.

[0099] When the sheet transported by the transport unit 32 is thin paper, the transmitted volume Q1 of the transmitted ultrasonic wave is greater than the reference transmitted volume Q2, as shown in Fig. 4(c) and Fig. 5. The volume detection unit 60 detects that the transmitted ultrasonic wave receiving unit 54 has received the transmitted volume Q1, and outputs the transmitted volume information.

[0100] The storage unit 70 stores the reference reflected sound volume P2 and the reference transmitted sound volume Q2.

[0101] Based on the comparison result between the reflected volume P3 indicated by the reflected volume information and the reference reflected volume P2, and the comparison result between the transmitted volume Q1 indicated by the transmitted volume information and the reference transmitted volume Q2, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is thin paper and that the sheets are not being transported in duplicate.

[0102] In other words, the discrimination unit 80 determines that the sheet being transported by the transport unit 32 is thin paper and that the sheets are not being fed in duplicate based on the comparison result indicating that the reflected volume P3 indicated by the reflected volume information is smaller than the reference reflected volume P2 and the comparison result indicating that the transmitted volume Q1 indicated by the transmitted volume information is larger than the reference transmitted volume Q2.

[0103] The control unit 20 controls the drive unit 22 based on the discrimination information.

[0104] The driving unit 22 drives the image forming unit 16 or the reading unit 11 .

[0105] The image forming unit 16 forms an image on a sheet.

[0106] The reading unit 11 reads an image written on a sheet (original).

[0107] The discharge section 18 discharges the sheet (original).

[0108] Next, with reference to FIG. 1 to FIG. 3, and further to FIG. 4(d) and FIG. 5, an embodiment in which sheets being conveyed through the conveying path 34 are being fed in multiple passes will be described.

[0109] According to the image forming device 10 of this embodiment, it is possible to determine whether thin paper is being transported or whether a double feed has occurred, thereby making it possible to prevent erroneous determination that a double feed has occurred when a double feed has not actually occurred.

[0110] Furthermore, according to the image forming device 10 of this embodiment, it is possible to determine whether thin paper is being transported or whether double feeding has occurred, thereby preventing the misdetermination that double feeding has occurred even when thin paper is being transported normally.

[0111] In the image forming device 10 of this embodiment, the discrimination unit 80 determines that the sheets being transported by the transport unit 32 are being double-fed based on a comparison result indicating that the reflected volume P3 indicated by the reflected volume information is smaller than the reference reflected volume P2 and a comparison result indicating that the transmitted volume Q3 indicated by the transmitted volume information is smaller than the reference transmitted volume Q2.

[0112] Furthermore, the image forming apparatus 10 according to the present embodiment further includes an image forming unit 16 and a control unit 20. The image forming unit 16 forms an image on a sheet. The control unit 20 controls the image forming unit. The control unit 20 stops driving the image forming unit 16 based on the discrimination result of the discrimination unit 80.

[0113] Furthermore, the image forming apparatus 10 according to the present embodiment further includes a reading unit 11 and a control unit 20. The reading unit 11 reads an image written on a sheet. The control unit 20 controls the reading unit 11. The control unit 20 stops driving the reading unit 11 based on the discrimination result of the discrimination unit 80.

[0114] In this embodiment, the process is the same as in the previous embodiment up to the point where the transmitting unit 50 transmits ultrasonic waves at a predetermined volume P in accordance with an instruction from the control unit 20, so a duplicated description will be omitted.

[0115] As shown in FIGS. 2 and 3, the reflected ultrasonic wave receiving unit 52 receives the reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet.

[0116] The volume detector 60 detects the reflected volume of the reflected ultrasonic wave and outputs reflected volume information. When the sheet being conveyed by the conveying unit 32 is being fed in duplicate, the reflected volume of the reflected ultrasonic wave is a reflected volume P3 that is smaller than the reference reflected volume P2, as shown in Fig. 4(d) and Fig. 5. The volume detector 60 detects that the reflected ultrasonic wave receiver 52 has received the reflected volume P3, and outputs transmitted volume information.

[0117] The transmitted ultrasonic wave receiving unit 54 receives transmitted ultrasonic waves that are the result of the transmitted ultrasonic waves passing through the sheet.

[0118] The volume detection unit 60 detects the transmitted volume Q of the transmitted ultrasonic wave and outputs the transmitted volume information. When the sheet being conveyed by the conveying unit 32 is being fed in duplicate, the transmitted volume Q of the transmitted ultrasonic wave is a transmitted volume Q3 that is smaller than the reference transmitted volume Q2, as shown in Fig. 4(d) and Fig. 5. The volume detection unit 60 detects that the transmitted ultrasonic wave receiving unit 54 has received the transmitted volume Q3, and outputs the transmitted volume information.

[0119] The storage unit 70 stores the reference reflected sound volume P2 and the reference transmitted sound volume Q2.

[0120] The discrimination unit 80 discriminates that the sheets being transported by the transport unit 32 are being fed in duplicate based on the comparison result between the reflected volume P3 indicated by the reflected volume information and the reference reflected volume P2, and the comparison result between the transmitted volume Q3 indicated by the transmitted volume information and the reference transmitted volume Q2.

[0121] In other words, the discrimination unit 80 determines that the sheets being transported by the transport unit 32 are being fed in duplicate based on a comparison result indicating that the reflected volume P3 indicated by the reflected volume information is smaller than the reference reflected volume P2 and a comparison result indicating that the transmitted volume Q3 indicated by the transmitted volume information is smaller than the reference transmitted volume Q2.

[0122] The control unit 20 controls the drive unit 22 based on the discrimination information.

[0123] The driving unit 22 stops driving the image forming unit 16 or the reading unit 11.

[0124] According to the image forming device 10 of this embodiment, it is possible to determine that a double feed has occurred rather than that a single sheet of plain paper, thick paper, or thin paper is being transported normally, and therefore it is possible to prevent erroneous determination that, for example, a single sheet of thick paper is being transported normally when a double feed has occurred.

[0125] Furthermore, according to the image forming device 10 of this embodiment, it is possible to determine whether plain paper, thick paper, or thin paper is being transported, or whether a double feed has occurred, thereby preventing the misdetermination that plain paper, thick paper, or thin paper is being transported normally even when a double feed has occurred.

[0126] Furthermore, according to the image forming device 10 of this embodiment, the operation of the image forming unit 16 or the reading unit 11 is stopped only when it is determined that a double feed has occurred, thereby preventing erroneous stopping of the operation of the image forming unit 16 or the reading unit 11 due to an erroneous determination of a double feed.

[0127] Next, information processing by the image forming apparatus 10 according to the present embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 and Fig. 7 are flow charts showing information processing by the image forming apparatus 10 according to the present embodiment.

[0128] 6 and 7, the flowchart includes steps S10 to S32. Specifically, the process is as follows.

[0129] 6, the feeding section 17 feeds a sheet stored in the feeding tray 12. The process proceeds to step S12.

[0130] In step S12, the conveying unit 32 conveys the sheet. The process proceeds to step S14.

[0131] In step S14, the transmitting unit 50 transmits ultrasonic waves at a predetermined volume P in accordance with an instruction from the control unit 20. The process proceeds to step S16.

[0132] In step S16, the reflected ultrasonic wave receiving unit 52 receives the reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet. The process proceeds to step S18.

[0133] In step S18, the volume detector 60 detects the reflected volumes (P1, P2, P3) of the reflected ultrasonic waves and outputs the reflected volume information. The process proceeds to step S20.

[0134] In step S20, the transmitted ultrasonic wave receiving unit 54 receives the transmitted ultrasonic wave that has been transmitted through the sheet.

[0135] In step S22, the volume detector 60 detects the transmitted volume (Q1, Q2, Q3) of the transmitted ultrasound, and outputs the transmitted volume information. The process proceeds to step S24.

[0136] In step S24 shown in Fig. 7, the determination unit 80 determines whether the reflected sound volume P2 indicated by the reflected sound volume information is equal to the reference reflected sound volume P2, or whether the reflected sound volume P1 indicated by the reflected sound volume information is greater than the reference reflected sound volume P2. If they are equal, the process proceeds to step S26. If they are greater, the process proceeds to step S30.

[0137] If the answer is Yes in step S24, in step S26, the determination unit 80 determines whether the transmitted sound volume Q2 indicated by the transmitted sound volume information is equal to the reference transmitted sound volume Q2 or whether the transmitted sound volume Q3 indicated by the transmitted sound volume information is smaller than the reference transmitted sound volume Q2.

[0138] If they are equal (Yes in step S26), the sheet is determined to be plain paper, and the process proceeds to step S28. If they are smaller (No in step S26), the sheet is determined to be cardboard, and the process proceeds to step S28.

[0139] In step S28, the image forming unit 16 forms an image on the sheet. The reading unit 11 reads the image written on the sheet (original). Then, the process ends.

[0140] Next, if the result in step S24 is No, then in step S30, it is determined whether or not the transmitted sound volume Q1 indicated by the transmitted sound volume information is greater than the reference transmitted sound volume Q2. If it is greater (Yes in step S30), the process proceeds to step S28. If it is smaller (No in step S30), the process proceeds to step S32.

[0141] In step S30, if the result is Yes, it is determined that the sheet being conveyed by the conveying unit 32 is thin paper and that the sheets are not being fed in duplicate, and in step S28, the image forming unit 16 forms an image on the sheet. The reading unit 11 reads the image written on the sheet (original). Then, the process ends.

[0142] If the result in step S30 is No, it is determined that multiple sheets have been fed, and in step S32, the driving unit 22 stops driving the image forming unit 16 or the reading unit 11. Then, the process ends.

[0143] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments, and can be implemented in various forms without departing from the scope of the present invention. The drawings are mainly schematic illustrations of each component for ease of understanding, and the thickness, length, number, etc. of each component shown in the drawings are different from the actual ones due to the convenience of drawing. In addition, the materials, shapes, dimensions, etc. of each component shown in the above embodiments are merely examples, and are not particularly limited, and various modifications are possible within a scope that does not substantially deviate from the effects of the present invention. [Industrial Applicability]

[0144] The present invention can be used in the field of image forming apparatuses. [Explanation of symbols]

[0145] 10 Image forming device 11 Reading unit 12 Feeding Tray 13 Control section 14 Display section 15 Input section 16 Image forming section 17 Feeding section 18 Discharge section 20 Control section 22 Drive unit 30 Pickup roller 32 Conveyor 34 Transport Path 50 Transmitter 52 Reflected ultrasonic receiver 54 Transmitted ultrasonic receiving unit 60 Volume detection section 70 Storage section 80 Discrimination part

Claims

1. A feeding section that feeds a sheet; A conveying unit that conveys the sheet; A transmission unit that transmits ultrasonic waves at a predetermined volume; a reflected ultrasonic receiving unit that receives a reflected ultrasonic wave that is the transmitted ultrasonic wave reflected by the sheet; a transmitted ultrasonic receiving unit that receives transmitted ultrasonic waves that are transmitted through the sheet; a sound level detection unit that detects a reflected sound level of the reflected ultrasonic wave and outputs reflected sound level information, and detects a transmitted sound level of the transmitted ultrasonic wave and outputs transmitted sound level information; a discrimination unit that discriminates a thickness of the sheet being conveyed by the conveying unit and discriminates whether the sheets are being fed in multiples based on a comparison result between the reflected sound volume indicated by the reflected sound volume information and a reference reflected sound volume and a comparison result between the transmitted sound volume indicated by the transmitted sound volume information and a reference transmitted sound volume; An image forming apparatus comprising:

2. 2. The image forming apparatus of claim 1, wherein the discrimination unit determines that the sheet being transported by the transport unit is plain paper and that the sheet is not being double-fed based on a comparison result indicating that the reflected volume indicated by the reflected volume information is equal to the reference reflected volume and a comparison result indicating that the transmitted volume indicated by the transmitted volume information is equal to the reference transmitted volume.

3. 2. The image forming apparatus of claim 1, wherein the discrimination unit determines that the sheet being transported by the transport unit is cardboard and that the sheets are not being fed in duplicate based on a comparison result indicating that the reflected volume indicated by the reflected volume information is greater than the reference reflected volume and a comparison result indicating that the transmitted volume indicated by the transmitted volume information is smaller than the reference transmitted volume.

4. The image forming apparatus of claim 1, wherein the discrimination unit determines that the sheet being transported by the transport unit is thin paper and that the sheets are not being fed in duplicate based on a comparison result indicating that the reflected volume indicated by the reflected volume information is smaller than the reference reflected volume and a comparison result indicating that the transmitted volume indicated by the transmitted volume information is larger than the reference transmitted volume.

5. The image forming apparatus of claim 1, wherein the discrimination unit discriminates that the sheet being transported by the transport unit is being double-fed based on a comparison result indicating that the reflected volume indicated by the reflected volume information is smaller than the reference reflected volume and a comparison result indicating that the transmitted volume indicated by the transmitted volume information is smaller than the reference transmitted volume.

6. An image forming unit that forms an image on the sheet; A control unit that controls the image forming unit; Further equipped with The discrimination unit discriminates that the sheet being conveyed by the conveying unit is thin paper and that the sheet being conveyed by the conveying unit is being fed in a double-feed state based on a comparison result indicating that the reflected sound volume indicated by the reflected sound volume information is smaller than the reference reflected sound volume and a comparison result indicating that the transmitted sound volume indicated by the transmitted sound volume information is smaller than the reference transmitted sound volume, The image forming apparatus according to claim 5 , wherein the control unit stops driving the image forming unit based on a determination result of the determination unit.

7. A reading unit that reads an image written on the sheet; A control unit that controls the reading unit; Further equipped with The discrimination unit discriminates that the sheet being conveyed by the conveying unit is thin paper and that the sheet being conveyed by the conveying unit is being fed in a double-feed state based on a comparison result indicating that the reflected sound volume indicated by the reflected sound volume information is smaller than the reference reflected sound volume and a comparison result indicating that the transmitted sound volume indicated by the transmitted sound volume information is smaller than the reference transmitted sound volume, The image forming apparatus according to claim 5 , wherein the control unit stops driving the reading unit based on a result of the determination by the determination unit.

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