Edge position detection device and image forming device

Abstract

An edge position detection device includes a light emitting device, a detection device, and a calculation circuit. The light emitting device includes a plurality of light sources having different emission wavelengths. The light emitting device irradiates the conveyed object with linear light along the width direction of the conveyed object, the width direction being perpendicular to the conveying direction of the conveyed object. The detection device detects the intensity of reflected light of the light emitted by the light emitting device at a plurality of positions in the width direction of the conveyed object. The calculation circuit calculates the position of the edge of the conveyed object in the width direction based on the detection result of the detection device.

Description

Technical Field

[0001] The present invention relates to an edge position detection device and an image forming device. Background Art

[0002] In an image forming apparatus, high image position accuracy relative to a printed material is required. However, when a sheet of paper is conveyed, the sheet of paper may be displaced in a width direction perpendicular to the conveying direction in the image forming apparatus, and it may become difficult to form an image at a desired position, which is problematic. In order to deal with the problems as described above, a technology for identifying the position of a conveyed sheet of paper and forming an image based on the identified position is known (e.g., Japanese Examined Patent Application Publication No. 2016-000656). In particular, the amount of displacement of the position of the sheet of paper in the width direction is detected by using an edge position detection sensor that detects the position of an edge of the sheet of paper on a conveying path.

[0003] The existing edge position detection sensor as described above includes a sensor including light sources having different wavelengths (colors), and sequentially turns on the light sources by using a signal that can obtain a maximum output power to identify the position of the edge of the paper. However, depending on the color or reflectivity of the paper, it may be difficult to obtain a desired output power even by using any light source that is sequentially turned on. Therefore, there is a problem in that it may be difficult to detect the precise position of the edge of the paper.

[0004] In addition, another method is known in which a plurality of light sources are turned on simultaneously to increase the light intensity, thereby detecting the position of the edge of the paper. However, in this method, a high output power is obtained independently of the color or reflectivity of the paper, but the light intensity may be too large for paper with high reflectivity. Therefore, there is a problem in that the power consumption of the sensor may increase.

[0005] An object of the present invention is to provide an edge position detection apparatus and an image forming apparatus capable of reducing power consumption and handling various sheets without deteriorating detection accuracy. Summary of the invention

[0006] According to one aspect of the present invention, an edge position detection device includes a light emitting device, a detection device and a calculation circuit. The light emitting device includes a plurality of light sources having different emission wavelengths. The light emitting device is configured to illuminate the conveyed object with linear light along the width direction of the conveyed object, the width direction being perpendicular to the conveying direction of the conveyed object. The detection device is configured to detect the intensity of reflected light of the light emitted by the light emitting device at a plurality of positions in the width direction of the conveyed object. The calculation circuit is configured to calculate the position of the edge of the conveyed object in the width direction based on the detection result of the detection device.

[0007] The present invention has the advantages of reducing power consumption and processing various papers without deteriorating the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a configuration diagram illustrating an example of the overall configuration of an image forming apparatus according to the first embodiment;

[0009] Figure 2 is a configuration diagram illustrating an example of a schematic configuration of a position detection sensor;

[0010] Figure 3 is a diagram illustrating an example of a circuit configuration of a position detection sensor and peripheral components;

[0011] Figure 4 is a functional block diagram illustrating an example of a functional configuration of an image forming apparatus according to the first embodiment;

[0012] Figure 5 is a diagram for explaining individual values ​​of current that may flow into a light emitting diode (LED) included in a light emitting unit;

[0013] Figure 6 is a diagram illustrating an example of settings of a light source and light intensity for each recording medium;

[0014] Figure 7 is a diagram for explaining the operation of the position detection sensor;

[0015] Figure 8 is a flowchart illustrating an example of the flow of processing performed by the position detection sensor of the first embodiment;

[0016] Fig. 9 is a functional block diagram illustrating an example of a functional configuration of an image forming apparatus according to a second embodiment; and

[0017] Fig.10 is a flowchart illustrating an example of the flow of processing performed by the position detection sensor of the second embodiment.

[0018] The accompanying drawings are intended to illustrate exemplary embodiments of the present invention and should not be interpreted as limiting its scope.In the various drawings, the same or similar reference numerals designate the same or similar components. DETAILED DESCRIPTION

[0019] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0020] As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0021] In describing the preferred embodiments shown in the drawings, specific terms may be employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terms so selected, and it will be understood that each specific element includes all technical equivalents having the same function, operating in a similar manner and achieving similar results.

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0023] First embodiment

[0024] An image forming apparatus 10 according to a first embodiment will be described below with reference to the drawings. Figure 1 is a configuration diagram illustrating an example of the overall configuration of the image forming apparatus according to the first embodiment.

[0025] Configuration of image forming apparatus

[0026] like Figure 1 As shown, the image forming apparatus 10 includes a writing unit 11, image forming units 12Y, 12M, 12C and 12K of a tandem electrophotographic system, a transfer belt 15, a secondary transfer roller 17, a paper feeding unit 18, a conveying roller pair 13, a fixing roller 14 and a reverse path 16.

[0027] Each of the image forming units 12Y, 12M, 12C, and 12K has an image forming process (a loading process, an exposure process, a developing process, a transfer process, and a cleaning process) in which a toner image is formed based on an instruction from the writing unit 11 and the toner image is transferred onto the transfer belt 15. Figure 1 In the example shown, a yellow toner image is formed on the image forming unit 12Y, a magenta toner image is formed on the image forming unit 12M, a cyan toner image is formed on the image forming unit 12C, and a black toner image is formed on the image forming unit 12K, and the toner images of the respective colors are transferred in a superimposed manner from the image forming units 12Y, 12M, 12C, and 12K onto the transfer belt 15. The type of toner or the number of colors is not limited to this example, and the type of toner or the number of colors may be modified as appropriate.

[0028] The transfer belt 15 moves in a predetermined direction, and conveys the toner images (full-color toner images) transferred in a superimposed manner from the image forming units 12Y, 12M, 12C, and 12K to the secondary transfer position of the secondary transfer roller 17. For example, the transfer belt 15 moves in a clockwise direction. The yellow toner image, the magenta toner image, the cyan toner image, and the black toner image are sequentially transferred in a superimposed manner, and the full-color toner image is transferred to the secondary transfer position.

[0029] The paper feeding unit 18 includes a paper feeding tray in which a conveyed object as a processing target, that is, a plurality of recording media 1, is loaded in a stacked manner. The paper feeding unit 18 feeds the recording media 1 one by one from the paper feeding tray to the conveying path a. The recording medium 1 is, for example, recording paper (transfer paper or paper), but is not limited thereto, and may be a different medium, such as coated paper, thick paper, overhead projector (OHP) sheet, plastic film, prepreg, or copper foil, as long as an image is recordable on the medium. For ease of understanding of the description, as shown in FIG. Figure 1 The XYZ coordinates are specified as shown. The Y axis indicates the conveying direction of the recording medium 1 at the position of the secondary transfer roller 17, that is, Figure 1 The X axis indicates the width direction of the recording medium 1, which is perpendicular to the conveying path a. The Z axis indicates the height direction of the image forming apparatus 10.

[0030] As an external option, in addition to the above-mentioned paper feeding unit 18, a paper feeding unit 18 capable of loading different kinds of recording media 1 can be further connected, and the recording medium 1 as the processing target can be transmitted from multiple paper feeding units 18 alternately or in a switching manner selected from multiple paper feeding units 18.

[0031] The transport roller pair 13 transports the recording medium 1 fed from the paper feeding unit 18 in the direction of the arrow s of the transport path a.

[0032] The secondary transfer roller 17 collectively transfers the full-color toner image conveyed by the transfer belt 15 onto the recording medium 1 conveyed by the conveying roller pair 13 at the secondary transfer position.

[0033] The fixing roller 14 applies heat and pressure to the recording medium 1 onto which the toner image has been transferred, and fixes the toner image to the recording medium 1 .

[0034] In the case of single-sided printing, the image forming apparatus 10 discharges the recording medium 1 to which the toner image is fixed. In addition, in the case of double-sided printing, the recording medium 1 to which the toner image is fixed is conveyed to the reverse path 16.

[0035] The reverse path 16 conveys the conveyed recording medium 1 in a rotating manner so that the opposite side of the recording medium 1 faces upward, and conveys the recording medium 1 in the direction of arrow t. The recording medium 1 conveyed by the reverse path 16 is conveyed again in the direction of arrow s by the conveying roller pair 13, a toner image is formed on the opposite side by the secondary transfer roller 17, the toner image is fixed by the fixing roller 14, and the recording medium is discharged.

[0036] The position detection sensor 20 includes a reading device 2 (see Figure 2), wherein a plurality of image sensors are aligned in the main scanning direction (X) of the recording medium 1. The reading device 2 is arranged so that the reading surface faces the conveying path a of the recording medium 1. The position detection sensor 20 detects the position of the edge of the processing target recording medium 1 in the sub-scanning direction (Y) based on the output value from the reading device 2, and corrects the position deviation of the recording medium 1 in the main scanning direction (X). The position detection sensor 20 is an example of an edge position detection device according to the present disclosure.

[0037] The image forming apparatus 10 includes an operation panel ( Figure 1 10). The operation panel inputs various operations to the image forming device 10. The operation panel displays various information on the image forming device 10. The image forming device 10 is not limited to the electrophotographic system as described above. In other words, the image forming device 10 may be a different printing system, such as an inkjet system. In addition, the image forming device 10 may be a continuous paper printer other than a cut-sheet paper printer.

[0038] Position detection sensor configuration

[0039] Will be referenced below Figure 2 An overview of the position detection sensor 20 is described. Figure 2 is a configuration diagram illustrating an example of a schematic configuration of a position detection sensor. In particular, Figure 2 The figure shows a reading device 2 included in the position detection sensor 20, and a recording medium 1 passing the position of the reading device 2. The recording medium 1 is transported in the transport direction (arrow s). Figure 2 In the figure, the conveying direction (arrow s) and the sub-scanning direction (Y-axis direction) of the recording medium 1 are the same direction. On the plane of the recording medium 1, the direction perpendicular to the sub-scanning direction (Y-axis direction) is the main scanning direction (X-axis direction).

[0040] The reading device 2 is, for example, a contact image sensor (CIS) in which a plurality of image sensors (for example, complementary metal oxide semiconductor (CMOS) image sensors) are linearly arranged. Figure 2 In the embodiment, the reading device 2 is arranged so that the reading surface is positioned in a direction facing one side of the recording medium 1 and is located close to the one side. All image sensors (2i, 2j, etc.) of the reading device 2 are arranged linearly along the main scanning direction (X). The reading device 2 irradiates the recording medium 1 as a reading target with illumination light so that the photodiode receives light reflected from each position (main scanning position) of the image sensor (2i, 2j, etc.) in the main scanning direction (X), and outputs a pixel signal at each main scanning position that has undergone photoelectric conversion as a signal output (image signal) in the main scanning direction (X).

[0041] At a position opposite to the reading device 2, a dedicated light blocking member for blocking and absorbing the illumination light from the reading device 2 is arranged. Figure 2 As shown, the reading device 2 is arranged across the edge 1a, which is the edge of the recording medium 1 in the main scanning direction (X). With this configuration, during the period of time when the recording medium 1 passes through the space between the reading device 2 and the light blocking member, the reading value (number of pixels) of the light at the main scanning position that does not receive the reflected light from the recording medium 1 becomes the smallest (see Figure 2 time period R1).

[0042] exist Figure 2 , the graph G represents the signal output (number of pixels) of the image sensor at each main scanning position consistent with the main scanning direction (X) of the reading device 2. As indicated by the graph G, the signal output (number of pixels) at each main scanning position of the reading device 2 during the passage of the recording medium 1 changes sharply near the position of the edge 1a, that is, near the position of the edge of the paper. When the reflectivity from the recording medium 1 is high, the difference in signal output between the two areas across the edge 1a increases. Therefore, the position of the edge 1a (edge ​​position), that is, the position of the edge of the paper can be detected by comparing the signal output at each main scanning position with a predetermined threshold value. Conversely, in the case where the reflectivity of the recording medium 1 is low, although not shown in the figure, the difference in output values ​​between the two areas across the edge 1a decreases. In this case, it is difficult to detect the edge position with high accuracy only by comparing the signal output at each main scanning position with a predetermined threshold value.

[0043] Will be referenced below Figure 3 A circuit configuration for controlling the position detection sensor 20 is described. Figure 3 2 is a diagram illustrating an example of a circuit configuration of a position detection sensor 20 and peripheral components. The reading device 2 includes a light emitting unit 2a and a light receiving unit 2b. The reading device 2 is connected to a constant current circuit 21, an analog-to-digital (AD) conversion circuit 22, a field programmable gate array (FPGA) 23, a central processing unit (CPU) 24, and a paper position control unit 25.

[0044] The light emitting unit 2a includes a plurality of light emitting diodes (LEDs) having different emission wavelengths. In the present embodiment, the light emitting unit 2a includes a red LED 3r, a green LED 3g, and a blue LED 3b. The red LED 3r, the green LED 3g, and the blue LED 3b are an example of a light source in the present disclosure. The light emitting unit 2a may also include an infrared LED (IR LED) in addition to the red LED 3r, the green LED 3g, and the blue LED 3b.

[0045] The light receiving unit 2b includes a sensor integrated circuit (IC) 4. The sensor IC 4 is, for example, a CMOS image sensor as described above.

[0046] The constant current circuit 21 generates an LED control signal 31 for controlling the emission state of the light emitting unit 2a based on the light intensity adjustment signal 34 and the on / off control signal 35 given from the FPGA 23. Then, the constant current circuit 21 controls the emission state of the light emitting unit 2a of each LED by giving the LED control signal 31 to the light emitting unit 2a. In other words, the constant current circuit 21 is connected to each of the red LED 3r, the green LED 3g and the blue LED 3b. The LED control signal 31 is a control signal for setting the emission number (for selecting one or more LEDs) in the light emitting unit 2a and / or setting the light intensity (determined by the current value and the current carrying time applied to the LED).

[0047] The AD conversion circuit 22 acquires an analog output 32 from the light receiving unit 2b. The AD conversion circuit 22 binarizes the received analog output 32 by using a comparator, and outputs a binarized digital output 33 to the FPGA 23. The threshold for binarization is given by a threshold setting signal 36 from the FPGA 23.

[0048] The FPGA 23 controls the operation of the constant current circuit 21 and the AD conversion circuit 22. In particular, the FPGA 23 gives the light intensity adjustment signal 34 and the on / off control signal 35 to the constant current circuit 21. The light emission control of the LED can be performed by directly turning on or off the light intensity adjustment signal 34. In this case, the on / off control signal 35 is not required. The FPGA 23 gives the threshold setting signal 36 to the AD conversion circuit 22. The FPGA 23 obtains the digital output 33 from the AD conversion circuit 22, and calculates the position of the edge of the recording medium 1 (transmitted object) in the width direction.

[0049] The CPU 24 controls the position shift correction function. Specifically, the CPU 24 gives the paper information 37 including the color information about the recording medium 1 as an example of the conveyed object to the FPGA 23. In addition, the CPU 24 acquires the position of the edge of the recording medium 1 (the conveyed object) in the width direction from the FPGA 23 as a detection result 38. Furthermore, the CPU 24 generates correction information 39 about the paper position with respect to the paper position control unit 25 based on the detection result 38, and sends the correction information 39 to the paper position control unit 25.

[0050] The paper position control unit 25 adjusts the position of the recording medium 1 in the main scanning direction (X) based on the detection result 38 acquired by the CPU 24, that is, the position of the edge of the recording medium 1 (the object being transported) in the width direction.

[0051] Instead of the paper position control unit 25, a print position control unit (not shown) may be arranged which controls the print position of the print information to be printed on the recording medium 1 based on the detection result 38, i.e., the position of the edge of the recording medium 1 (the conveyed object) in the width direction.

[0052] Although Figure 3 The case where the position detection sensor 20 outputting analog information is used is shown in the figure, but the position detection sensor 20 may be configured to perform AD conversion inside the sensor and output digital information. In this case, the AD conversion circuit 22 is not required.

[0053] Functional configuration of image forming apparatus

[0054] Will be referenced below Figure 4 The functional configuration of the image forming apparatus 10 is described. Figure 4 is a functional block diagram illustrating an example of a functional configuration of the image forming apparatus according to the first embodiment.

[0055] like Figure 4 As shown, the image forming apparatus 10 includes a setting unit 41, a light emitting unit 42, a detection unit 43, a calculation unit 44, a control unit 45, and a correction unit 51. Among these units, the setting unit 41, the light emitting unit 42, the detection unit 43, the calculation unit 44, and the control unit 45 are provided in the position detection sensor 20.

[0056] The setting unit 41 sets the properties of the recording medium 1 in advance for each recording medium 1 (transmitted object). Specifically, the setting unit 41 generates and stores setting data in which the properties of the recording medium 1 (for example, information indicating the type or thickness of paper) are linked to the light emission state of the light emitting unit 42 when detecting the position of the edge of the recording medium 1 (for example, information indicating the type of light source (LED) to be turned on, and the light intensity (light emission time or current value)). The CPU 24 is an example of the setting unit 41 as a setting circuit.

[0057] The light emitting unit 42 includes a plurality of light sources having different emission wavelengths, and irradiates the recording medium 1 (transmitted object) with linear light in the width direction of the recording medium 1. The light emitting unit 2a including the red LED 3r, the green LED 3g, and the blue LED 3b is an example of the light emitting unit 42 as the light emitting device.

[0058] The detection unit 43 detects the intensity of reflected light of the light emitted by the light emitting unit at a plurality of positions on the recording medium 1 (transported object) in the width direction. The sensor IC 4 as described above is one example of the detection unit 43 as the detection means.

[0059] The calculation unit 44 calculates the position of the edge of the recording medium 1 (the object being conveyed) in the width direction based on the detection result of the detection unit 43. The FPGA 23 as described above is one example of the calculation unit 44 as a calculation circuit.

[0060] With respect to each light source included in the light emitting unit 42, the control unit 45 controls the type of the light source that emits light and the light intensity of the light source based on the information set by the setting unit 41. The constant current circuit 21 as described above is an example of the control unit 45 as a control circuit. It is sufficient that the control unit 45 controls at least one of the type of the light source that emits light and the light intensity of the light source based on the information set by the setting unit 41 with respect to each light source included in the light emitting unit 42.

[0061] The correction unit 51 corrects the position of the recording medium 1 and / or the print position of the print information to be printed on the recording medium 1 based on the position of the edge of the recording medium 1 (the object being conveyed). Specifically, the position is corrected by using a known method, for example, in which the position of the recording medium 1 is adjusted by using a conveying position adjustment unit (not shown) to correct the displacement of the recording medium 1 in the main scanning direction (X) on the conveying path to a reference position. The paper position control unit 25 and the print position control unit described above are each an example of the correction unit 51 as a correction circuit.

[0062] Description of an example of the settings of the light source to be turned on

[0063] Will be referenced below Figure 5 and Figure 6 An example of the setting of the light emitting unit 42 to be turned on by the position detection sensor 20 is described. Figure 5 is a diagram for explaining individual values ​​of current that may flow to an LED included in a light emitting unit. Figure 6 is a diagram illustrating an example of settings of a light source and light intensity for each recording medium.

[0064] exist Figure 5 , the maximum value of the current that can flow to the light emitting unit 2a in the case of single color light emission among the red LED 3r, the green LED 3g, and the blue LED 3b and in the case of three colors (all colors) light emission is illustrated. The total amount of the value of the current that can flow to the light emitting unit 2a is limited by the heat of the circuit package. Figure 5 As shown in the graph in , the maximum value of the current that can flow varies depending on the number of LEDs that are turned on. In particular, Figure 5In the example in , the maximum value is 50 mA when emitting a single color of light, 62.5 mA in total when emitting two colors of light, and 75 mA in total when emitting three colors of light. Note that the specific current value varies depending on the specifications of the LED to be used.

[0065] When the recording medium 1 has a high dependence on color, a sufficiently high signal output can be obtained by monochromatic emission using a light source corresponding to the wavelength of the color of the paper without increasing the amount of light emission. Figure 6 In the example of FIG. 1 , a case is illustrated in which blue light is generated by turning on the blue LED 3 b relative to the “blue paper”, and a signal output that can detect the position of the edge of the paper can be obtained while suppressing the current value (total 50 mA). Figure 6 In the example in , a case is illustrated in which green light is generated by turning on the green LED 3g with respect to the "red paper", and a signal output that can detect the position of the edge of the paper can be obtained while suppressing the current value (50 mA in total).

[0066] On the contrary, when the recording medium 1 has no color dependence (e.g., black paper with high light absorption, transparent paper with transparent background, etc.), it is difficult to obtain a high signal output even by using any light source with different wavelengths. Therefore, a detectable signal output is obtained by increasing the emission intensity by turning on multiple LEDs at the same time. Figure 6 In the example in FIG. 1 , the red LED 3r, the green LED 3g, and the blue LED 3b are turned on, and a signal output that can detect the position of the edge of the paper can be obtained while suppressing the current value (total 60 mA). Figure 6 In the example in FIG. 1 , the red LED 3r, the green LED 3g, and the blue LED 3b are turned on, and a signal output at which the position of the edge of the paper can be detected can be obtained at the maximum current value (75 mA in total).

[0067] Even when a plurality of LEDs are turned on at the same time, unnecessary consumption current can be reduced by setting an optimal light intensity by adjusting at least one of the number of LEDs to be turned on and the amount of light emission, without turning on all LEDs at the maximum current. Figure 6 In the example in , pink light is generated by turning on only the red LED 3r and the blue LED 3b, and a signal output that can detect the position of the edge of the paper can be obtained while suppressing the current value (45 mA in total). Figure 6In the example in , only the red LED 3r and the green LED 3g are turned on, and a signal output that can detect the position of the edge of the paper can be obtained while suppressing the current value (62 mA in total).

[0068] Description of the operation of the position detection sensor

[0069] Will be referenced below Figure 7 The operation of the position detection sensor 20 is described. Figure 7 is a diagram for explaining the operation of the position detection sensor. Figure 7 The left side of the figure shows that when the pink recording medium 1 is detected and the red LED 3r, the green LED 3g and the blue LED 3b (see Figure 3 ) are all turned on. Figure 7 The right side of shows the signal output obtained when the fanned recording medium 1 is detected and only the red LED 3r and the blue LED 3b are turned on at the same time.

[0070] According to the signal output of the monochromatic light source shown in the figure Figure 7 On the left side, the signal output R of the red LED 3r changes most significantly between the light shielding member and the recording medium 1. However, it can be found that it is difficult to obtain an output power greater than the threshold by turning on any one LED independently. Therefore, it is difficult to detect the position of the edge of the pink recording medium 1 by a monochromatic light source.

[0071] On the contrary, Figure 7 The right side of the diagram shows that each light with a wavelength corresponding to pink is output by turning on the red LED 3r and the blue LED 3b at the same time based on the paper information, that is, based on the color of the paper. In this case, it can be found that the signal output "R+B" exceeds the threshold value and the position of the edge of the pink recording medium 1 can be detected. In this way, by selecting the light source to be turned on based on the color of the recording medium (such as the color of the paper), the position of the edge of various recording media 1 can be detected.

[0072] If the red LED 3r, the green LED 3g, and the blue LED 3b are simply turned on at the same time in the reading device 2, the amount of light emission is too large for a paper having a high reflectivity (that is, a low light absorption rate). In this case, the power consumption of the position detection sensor 20 increases. On the contrary, if Figure 7 As shown on the right side of FIG. 1 , the power consumption of the position detection sensor 20 can be reduced by selectively turning on the light sources corresponding to the paper.

[0073] In addition, when a plurality of LEDs are turned on simultaneously, instead of turning on the LEDs at maximum light intensity, it is possible to reduce unnecessary consumption current and achieve energy saving in an existing multi-lighting system by turning on those LEDs while adjusting the amount of light emission.

[0074] As to the light source and the degree of light intensity to be adopted for a certain paper, it is sufficient that the setting unit 41 as described above performs evaluation experiments or the like in advance and generates setting data in which the attribute (the way of conveyance) of the recording medium 1 and the light emission state of the light emitting unit 42 capable of detecting the position of the edge of the recording medium 1 are linked. The generated setting data is stored in a storage unit ( Figure 3 (not shown), is read when printing starts, and is used when detecting the position of the edge of the recording medium 1.

[0075] Description of the flow of processing performed by the position detection sensor

[0076] Will be referenced below Figure 8 The flow of processing performed by the position detection sensor 20 is described. Figure 8 is a flowchart illustrating an example of processing performed by the position detection sensor of the first embodiment.

[0077] The FPGA 23 (calculation unit 44) acquires the paper information (37) from the CPU 24 (setting unit 41) (step S11).

[0078] The FPGA 23 determines whether the setting data indicating the light emission state of the light emitting unit 42 is linked to the paper information (step S12). When it is determined that the setting data is linked to the paper information ("Yes" at step S12), the process proceeds to step S13. On the contrary, when it is determined that the setting data is not linked to the paper information ("No" at step S12), the process proceeds to step S14.

[0079] When it is determined as "YES" in step S12, the FPGA 23 acquires the setting data of the light emitting unit from the CPU 24 (step S13). Thereafter, the process proceeds to step S15.

[0080] When the determination is "NO" in step S12, the FPGA 23 makes settings to turn on all the light sources at the maximum light intensity (step S14). Thereafter, the process proceeds to step S15.

[0081] The FPGA 23 causes the constant current circuit 21 (control unit 45) to control the light emission of the light sources (the red LED 3r, the green LED 3g, and the blue LED 3b) based on the result obtained at step S13 or step S14 (step S15).

[0082] The FPGA 23 (calculation unit 44) performs detection of the position of the edge of the recording medium 1 (step S16).

[0083] The CPU 24 sends correction information 39 based on the detection result 38 of the position of the edge of the recording medium 1 to the paper position control unit 25 (step S17 ).

[0084] The paper position control unit 25 corrects the paper position or the printing position (step S18 ).

[0085] The image forming apparatus 10 performs printing in a state where the paper position or the printing position has been corrected (step S19). Then, the image forming apparatus 10 terminates the process. Figure 8 in the processing.

[0086] As described above, according to the position detection sensor 20 (edge ​​position detection device) of the first embodiment, the control unit 45 controls the type of light source to be turned on and / or the light intensity of the light source in the light emitting unit 42. The light emitting unit 42 includes a plurality of light sources having different emission wavelengths, and irradiates the recording medium 1 (transmitted object) with linear light in the width direction of the recording medium 1. Then, the detection unit 43 detects the intensity of the reflected light of the light emitted by the light emitting unit 42 at a plurality of positions on the recording medium 1 in the width direction, and the calculation unit 44 calculates the position of the edge of the recording medium 1 based on the detection result of the detection unit 43. Therefore, it is possible to reduce the power consumption of the position detection sensor 20 and process various recording media 1 without deteriorating the detection accuracy of the position of the edge of the recording medium 1.

[0087] In addition, according to the position detection sensor 20 (edge ​​position detection device) of the first embodiment, the setting unit 41 sets the attribute of the recording medium 1 in advance for each recording medium 1 (transmitted object). Then, the control unit 45 controls the type of light source to be turned on and / or the light intensity of the light source based on the setting content of the setting unit 41. Therefore, setting data in which the light emission state of the light emitting unit 42 is defined for each recording medium 1 can be prepared in advance. Therefore, printing of images and characters can be effectively performed.

[0088] Furthermore, according to the image forming apparatus 10 of the first embodiment, the correction unit 51 corrects the position of the recording medium 1 (the object being conveyed) and / or the print position of the print information to be printed on the recording medium 1 based on the position of the edge of the recording medium 1 (the object being conveyed). Therefore, the printing of the image and the characters can be performed at the appropriate positions on the recording medium 1.

[0089] Second embodiment

[0090] An image forming device 10a according to a second embodiment will be described below with reference to the accompanying drawings. The image forming device 10a includes a position detection sensor 20a (edge ​​position detection device). Before performing printing of an image or a character, the image forming device 10a transports the recording medium 1 set on the transport path a in the sub-scanning direction (Y) to a position where the reading device 2 can detect the position of the edge of the recording medium 1. Thereafter, the position detection sensor 20a turns on a plurality of different combinations of light sources included in the reading device 2 and compares the signal output detected by the detection unit 43 in each case. Then, the position detection sensor 20a determines the combination of light sources that is optimal for detecting the position of the edge of the set recording medium 1 and / or determines the light intensity of the light source. The image forming device 10a turns on a plurality of light sources included in the reading device 2 according to the selected light source combination and / or the selected light intensity, detects the position of the edge of the recording medium 1, and performs printing of an image or a character at a predetermined position on the recording medium 1. Note that the hardware configuration of the position detection sensor 20a is similar to the hardware configuration of the position detection sensor 20 described above (see Figure 3 ) is the same as that in FIG. 1 , and therefore, its description will be omitted. In addition, in the following description, the same Figure 3 The same names and same reference numerals are shown.

[0091] Functional configuration of image forming apparatus

[0092] Will be referenced below Fig. 9 The functional configuration of the image forming apparatus 10 a is described. Fig. 9 is a functional block diagram illustrating an example of a functional configuration of an image forming apparatus according to the second embodiment.

[0093] like Fig. 9 As shown, the image forming apparatus 10a includes a light emitting unit 42, a detection unit 43, a calculation unit 44, a control unit 45a, and a correction unit 51. Among these units, the light emitting unit 42, the detection unit 43, the calculation unit 44, and the control unit 45a are provided in the position detection sensor 20a.

[0094] When the plurality of light sources (the red LED 3r, the green LED 3g, and the blue LED 3b) of the light emitting unit 42 are turned on in a plurality of different combinations (combinations of types of light sources to be turned on and light intensities), the control unit 45a compares the signal output detected by the detection unit 43, and selects a combination of light sources and / or selects the light intensities of the light sources for detecting the position of the edge of the recording medium 1. In addition, the control unit 45a controls the emission state of each light source included in the light emitting unit 42 based on the selected information. Figure 3 The CPU 24 and the constant current circuit 21 in FIG. 2 are each an example of a control unit 45 a as a control circuit.

[0095] The operations of other functional units are the same as those described in the first embodiment, and therefore, description thereof will be omitted.

[0096] Description of the flow of processing performed by the position detection sensor

[0097] Will be referenced below Fig.10 The flow of processing performed by the position detection sensor 20 a is described. Fig.10 is a flowchart illustrating an example of the flow of processing performed by the position detection sensor of the second embodiment.

[0098] The image forming apparatus 10 a conveys the recording medium 1 (paper) to a predetermined position where the position of the edge of the recording medium 1 can be detected (step S21 ).

[0099] The CPU 24 (control unit 45a) causes the constant current circuit 21 to turn on a plurality of different combinations of light sources included in the light emitting unit 42. In addition, the sensor IC 4 (detection unit 43) acquires a signal output each time the light emitting unit 42 emits light in a different pattern (step S22).

[0100] The CPU 24 (control unit 45a) compares the signal outputs acquired at step S22, and selects a combination of light sources and / or selects the light intensity of the light sources (step S23).

[0101] The FPGA 23 causes the constant current circuit 21 (control unit 45 a ) to turn on the light sources (the red LED 3 r , the green LED 3 g , and the blue LED 3 b ) based on the paper information 37 acquired from the CPU 24 (step S24 ).

[0102] The FPGA 23 (calculation unit 44) performs detection of the position of the edge of the recording medium 1 (step S25).

[0103] The CPU 24 sends the correction information 39 based on the detection result 38 of the position of the edge of the recording medium 1 to the paper position control unit 25 (step S26 ).

[0104] The paper position control unit 25 corrects the paper position or the printing position (step S27 ).

[0105] The image forming apparatus 10a performs printing in a state in which the paper position or the printing position has been corrected (step S28). Then, the image forming apparatus 10a completes Fig.10 in the processing.

[0106] As described above, according to the position detection sensor 20a (edge ​​position detection device) of the second embodiment, when a plurality of different combinations of light sources included in the light emitting unit 42 are turned on with different light intensities, the control unit 45a compares the signal output detected by the detection unit 43, and selects a combination of light sources for detecting the position of the edge of the recording medium 1, and / or selects the light intensity of the light source. Therefore, even for the recording medium 1 in which the setting data described above in the first embodiment is not set, the position of the edge of the recording medium 1 can be detected with high accuracy and low power consumption. Note that when the type of paper (e.g., the color of the paper) is known in advance, the combination conditions of the light sources can be limited. For example, when it is known that the color of the paper is red, it is not necessary to turn on the combination of all RGB LEDs, but it is sufficient to turn on only the red LED 3r and adjust only the light intensity (current value) or the light emission time of the red LED 3r.

[0107] According to the present invention, the positions of the edges of various sheets can be accurately detected while reducing power consumption without deteriorating the detection accuracy.

[0108] The above embodiments are illustrative and do not limit the present invention. Thus, it is possible to consider that many additional modifications and variations of the above teachings are possible. For example, within the scope of the present disclosure and the appended claims, at least one element of the different illustrative and exemplary embodiments herein may be combined with each other or substituted with each other. In addition, the features of the components of the embodiments, such as number, position and shape, do not limit the embodiments and may therefore be preferably arranged. It is therefore understood that within the scope of the appended claims, the disclosure of the present invention may be practiced outside of what is specifically described herein.

[0109] Each function in the described embodiments may be implemented by one or more processing circuits or circuit systems. Processing circuits include programmed processors because processors include circuit systems. Processing circuits also include devices such as application specific integrated circuits (ASICs), digital signal processors (DSPs), field programmable gate arrays (FPGAs), and existing circuit components arranged to perform the described functions.

Claims

1. An edge position detection device, comprising: a light emitting device including a plurality of light sources having different emission wavelengths, the light emitting device being configured to illuminate the conveyed object with linear light along a width direction of the conveyed object, the width direction being perpendicular to a conveying direction of the conveyed object; a detection device configured to detect the intensity of reflected light of the light emitted by the light emitting device at a plurality of positions in the width direction of the conveyed object; a selection circuit configured to select a set of selected light sources from the plurality of light sources based on a property of the conveyed object, wherein the property includes a thickness of the conveyed object and / or a type of the conveyed object; a control circuit configured to control light emission of the plurality of light sources to simultaneously illuminate the group of selected light sources; a calculation circuit configured to calculate the position of the edge of the conveyed object in the width direction based on the detection result of the detection device; and The control circuit is also configured to control the light emission of the multiple light sources when detecting the position of the edge of the transmitted object according to a light emitting state selected from a plurality of light emitting states, each light emitting state specifying which light source is turned on and its corresponding light intensity, wherein the plurality of different light emitting states includes at least one light emitting state in which more than one of the multiple light sources are turned on simultaneously.

2. The edge position detection device according to claim 1, wherein: The control circuit is configured as follows: turning on the light sources according to the plurality of light emitting states, and comparing the intensities of the light detected by the detection device when the plurality of light sources are turned on according to the plurality of light emitting states; and Based on the comparison, the light emission state of the light source to be used for detecting the position of the edge of the conveyed object is selected.

3. The edge position detection device according to claim 1, wherein: The control circuit controls the light emission state to be used for detecting the position of the edge of the conveyed object based on setting contents.

4. The edge position detection device according to claim 1, wherein: The control circuit is configured to control the light emission state to be used for detecting the position of the edge of the conveyed object based on the type of the conveyed object.

5. The edge position detection device according to claim 2, wherein: The control circuit controls the light emission state to be used for calculating the position of the edge based on the color of the transmitted object.

6. The edge position detection device according to any one of claims 2 to 5, wherein: When two or more of the plurality of light sources are turned on in combination, the control circuit controls the timing and intensity of light emission of each of the two or more light sources.

7. An image forming device comprising: The edge position detection device according to any one of claims 1 to 6; and A correction circuit is configured to correct the position of the conveyed object and / or the printing position of the printing information to be printed on the conveyed object based on the position of the edge of the conveyed object detected by the edge position detection device.

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