Sheet type discrimination device and sheet type discrimination method

Abstract

To more appropriately correct a condition used for discrimination of the type of a sheet.SOLUTION: A sheet type discrimination device of one side of the present invention comprises: a physical property value detection unit 26 that detects the physical property value of a sheet; a sheet type discrimination unit 17 that discriminates the type of the sheet based on the physical property value of the sheet detected by the physical property value detection unit 26 and a predetermined condition indicated by the physical property value; an input unit that receives input of information on the type of the sheet; and a condition change unit 18 that, when the type of the sheet input to the input unit and the type of the sheet discriminated by the sheet type discrimination unit 17 are different from each other, calculates the difference between a first physical property value of the sheet detected by the physical property value detection unit 26 and a second physical property value associated with the sheet input to the input unit, and corrects the condition with the difference as a shift amount.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a sheet type discrimination device and a sheet type discrimination method.

Background Art

[0002] Conventionally, an image forming apparatus provided with a media sensor for detecting the basis weight, paper type, etc. of a sheet has been known. Such an image forming apparatus adjusts (controls the image forming process) the image forming conditions based on the detection result by the media sensor and a database of paper types provided in advance.

[0003] However, since there are limitations to the paper types that can be grasped at the product development stage of the image forming apparatus, the database of paper types does not cover information on all paper types distributed worldwide when the image forming apparatus is used by users. Therefore, there were limitations to the performance of paper type discrimination performed with paper type data that could not be grasped.

[0004] Patent Document 1 describes a paper type detection unit that detects the paper type of a conveyed sheet based on the detection result of a media sensor provided in advance in the paper conveyance path and a paper type detection table provided in advance, and a paper type determination unit that determines whether the detected paper type of the detected sheet matches the set paper type of the paper set under the set conditions, and a query unit that displays a paper type selection screen on which the user can select the paper type of the paper and queries the user for a selection of a predetermined paper type, and a table correction unit that corrects the paper type detection table so that the detected paper type becomes the selected paper type when the selected paper type of the selected sheet is different from the detected paper type.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the technique described in Patent Document 1, the correction of the threshold value for partitioning the area indicating the paper type of the paper is performed for a certain range of areas such as a circle, based on the measurement points (detection results of the media sensor) of the reciprocal of the reflectance and transmittance corresponding to the detected paper type.

[0007] And as a method for correcting the threshold value, various methods are described, such as changing the radius of the circle centered on the measurement point, or centering on the intersection point of the perpendicular line dropped to the existing threshold value closest to the measurement point, and using the value obtained by multiplying the distance between the measurement point and the intersection point by a predetermined magnification as the radius, and changing the size of the semi-circle of the radius.

[0008] However, Patent Document 1 does not show the appropriate values of the size of these semi-circles or the magnification of the change when changing the radius of the semi-circle, and only values with unclear bases are exemplified, such as "for example, 1.2 times, 1.5 times, etc.". Therefore, if the size of the semi-circle is not set appropriately, the discrimination accuracy of the paper type may decrease.

[0009] Also, Patent Document 1 describes that the user may specify the correction amount of the threshold value, such as the size of the circle centered on the measurement point, the magnification of the radius, etc. However, if the user cannot determine the appropriate correction amount, it is assumed that the accuracy of paper type detection will be further reduced when the threshold value is corrected based on the correction amount specified by the user.

[0010] The present invention has been made in view of such a situation, and an object of the present invention is to be able to more appropriately correct the conditions used for discriminating the type of the sheet.

Means for Solving the Problems

[0011] To solve the above problems, a sheet type discrimination apparatus reflecting one aspect of the present invention includes a physical property value detection unit that detects a physical property value of a sheet, a physical property value of the sheet detected by the physical property value detection unit, and a sheet type discrimination unit that discriminates the type of the sheet based on a predetermined condition indicated by the physical property value, an input unit into which information on the type of the sheet is input, and a condition change unit that calculates a difference between a first physical property value of the sheet detected by the physical property value detection unit and a second physical property value associated with the sheet input into the input unit when the type of the sheet input into the input unit is different from the type of the sheet discriminated by the sheet type discrimination unit, and corrects the condition using the difference as a shift amount. The condition is a threshold value for classifying the type of sheet. The physical property value detection unit converts the detected physical property value into basis weight and outputs it. The threshold value is indicated by the upper limit value and the lower limit value of the basis weight of the sheet. The condition change unit corrects the threshold value by increasing or decreasing the threshold value by the amount of shift in the direction of making the first physical property value match the second physical property value. The display control unit further includes a display control unit that causes the display unit to display a sheet type setting screen on which information on the types of a plurality of sheets including the information on the type of sheet determined by the sheet type determination unit is displayed in a selectable form. The type of sheet selected on the sheet type setting screen is input to the input unit. The upper limit value and the lower limit value of the threshold value are set to values that allow for variations in the sheet or variations in the physical property value detection unit. The condition change unit corrects the threshold value using each step obtained by dividing the range indicated by the upper limit value and the lower limit value of the threshold value by a predetermined number as the unit of change.

[0012] Also, a sheet type discrimination method reflecting one aspect of the present invention includes a procedure for detecting a physical property value of a sheet When the physical property value detection unit a procedure for discriminating the type of the sheet based on the detected physical property value of the sheet and a predetermined condition indicated by the physical property value, When the sheet type determination unit a procedure for inputting information on the type of the sheet, At the input unit and when the type of the input sheet is different from the type of the discriminated sheet, calculating a difference between a first physical property value of the detected sheet and a second physical property value associated with the input sheet, and correcting the condition using the difference as a shift amount. When the condition change unit The method includes the above procedures. The condition is a threshold value for classifying the type of sheet. The physical property value detection unit converts the detected physical property value into basis weight and outputs it. The threshold value is indicated by the upper limit value and the lower limit value of the basis weight of the sheet. The condition change unit corrects the threshold value by increasing or decreasing the threshold value by the amount of shift in the direction of making the first physical property value match the second physical property value. The display control unit further includes a display control unit that causes the display unit to display a sheet type setting screen on which information on the types of a plurality of sheets including the information on the type of sheet determined by the sheet type determination unit is displayed in a selectable form. The type of sheet selected on the sheet type setting screen is input to the input unit. The upper limit value and the lower limit value of the threshold value are set to values that allow for variations in the sheet or variations in the physical property value detection unit. The condition change unit corrects the threshold value using each step obtained by dividing the range indicated by the upper limit value and the lower limit value of the threshold value by a predetermined number as the unit of change.

Advantages of the Invention

[0013] According to the present invention, the conditions used for discriminating the type of the sheet can be corrected more appropriately. Problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, a form example for carrying out the present invention will be described with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same function or configuration are denoted by the same reference numerals, and redundant description of the components is omitted.

[0016] <Configuration of Image Forming Apparatus> First, with reference to FIG. 1, the schematic configuration of the image forming apparatus 100 according to the present embodiment will be described. FIG. 1 is a diagram showing a schematic configuration example of the image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 (an example of a sheet type discrimination apparatus) is a multifunction peripheral (MFP) that forms an image by an electrophotographic method. Note that the image forming method of the image forming apparatus is not limited to the electrophotographic method, and other methods such as an inkjet method may be used. Further, the image forming apparatus 100 may be an apparatus that only forms an image instead of a multifunction peripheral.

[0017] As shown in FIG. 1, the image forming apparatus 100 includes an image forming apparatus main body 1, a paper feeding cabinet unit 2, an operation display unit 3, and a cover unit 4.

[0018] The image forming apparatus main body 1 includes a power supply 10, a control unit 11, paper feeding trays 12-1 and 12-2, an image forming unit 20, a registration roller 25, a basis weight detection sensor 26, and a paper discharge tray 27.

[0019] The power supply 10 supplies power to each part constituting the image forming apparatus 100. The control unit 11 controls the operations of each part constituting the image forming apparatus 100. The paper feeding trays 12-1 and 12-2 are trays for accommodating sheets (papers). In the present embodiment, a paper feeding cabinet unit 2 having paper feeding trays 12-3 and 12-4 is also provided at the lower part of the image forming apparatus main body 1. Different sheets such as paper types and sizes are accommodated in the paper feeding trays 12-1 to 12-4. In the following description, when it is not necessary to distinguish the paper feeding trays 12-1 to 12-4 from each other, these are collectively referred to as the paper feeding tray 12.

[0020] The image forming unit 20 includes imaging units 21Y, 21M, 21C, and 21K for forming toner images of respective colors of Y (yellow), M (magenta), C (cyan), and K (black), an intermediate transfer unit 22, a secondary transfer roller 23, and a fixing unit 24.

[0021] The imaging unit 21Y includes a photosensitive drum 211Y, a charger arranged around the photosensitive drum 211Y, and a developing device (each shown as a circle in the figure). The imaging unit 21Y develops an electrostatic latent image drawn on the photosensitive drum 211Y by light irradiated from a laser scanning optical unit (not shown) by moving negatively charged toner from the developing device to the photosensitive drum, and forms a yellow toner image.

[0022] Note that since the configurations of the imaging units 21M, 21C, and 21K are the same as that of the imaging unit 21Y, the description of these configurations is omitted here. Also, in the following description, when it is not necessary to distinguish each of the photoreceptor drums 211Y, 211M, 211C, and 211K, they are collectively referred to as the photoreceptor drum 211.

[0023] The intermediate transfer unit 22 includes an intermediate transfer belt 221 that is rotationally driven, and primary transfer rollers 222Y, 222M, 222C, and 222K. In the following description, when it is not necessary to distinguish each of the primary transfer rollers 222Y, 222M, 222C, and 222K, they are collectively referred to as the primary transfer roller 222.

[0024] The intermediate transfer unit 22 performs primary transfer and synthesis of the toner images formed on each photoreceptor drum 211 onto the intermediate transfer belt 221 by the electric field applied from the primary transfer roller 222 disposed at a position facing each photoreceptor drum 211 of the imaging unit 21. The synthesized image is transferred to a sheet (an example of a recording material) by the secondary transfer roller 23.

[0025] The fixing unit 24 includes a heating roller 241 and a pressure roller 242. The heating roller 241 and the pressure roller 242 are in contact with each other to form a nip. The heating roller 241 is heated by an IH (Induction Heating) or a halogen heater (not shown) etc. that is not illustrated. The heating roller 241 rotates in accordance with the rotation of the pressure roller 242. When the sheet is fed into the nip, the sheet is heated by the heating roller 241. As a result, the toner is fixed to the sheet. Also, the fixing unit 24 includes a temperature detection unit (not shown) that is a thermistor, for example. The sheet on which the toner is fixed is discharged to the paper discharge tray 27.

[0026] The registration roller 25 is a roller provided at the upper and lower parts of the sheet being conveyed in the sheet conveyance path Tp. By bringing the end of the sheet into contact with the nip between the roller provided at the upper part of the sheet and the roller provided at the lower part, the registration roller 25 corrects skewing, rotation, etc. of the sheet being conveyed on the conveyance path Tp. An areal weight detection sensor 26 is provided upstream of the registration roller 25 in the sheet conveyance direction of the conveyance path Tp. The areal weight detection sensor 26 (an example of a physical property value detection unit) detects the areal weight of the sheet being conveyed on the conveyance path Tp. The areal weight detection sensor 26 will be described in detail with reference to FIG. 3 described later.

[0027] The operation display unit 3 is configured by, for example, a touch panel in which a touch sensor as an operation input unit (an example of an input unit) and a display panel as a display unit are integrally formed. Note that the operation input unit and the display unit may be configured separately, for example, as a mouse, a keyboard, and a display panel or the like. Based on the control by the display control unit 16 described later, a sheet type setting screen Sc1 (see FIG. 7) is displayed on the operation display unit 3.

[0028] The sheet type setting screen Sc1 is a screen in which the type of the sheet determined by the sheet type determination unit 17 and the type of the sheet estimated from the areal weight detected by the areal weight detection sensor 26 are displayed as selectable buttons. The sheet type setting screen Sc1 is displayed on the display unit of the operation display unit 3 (see FIG. 1) (or the display unit of a terminal device not shown, etc.) when a user such as a service technician (maintenance staff) or user administrator of the image forming apparatus 100 instructs a transition to a learning mode for learning the type of the sheet.

[0029] Learning of the sheet type in the learning mode is performed, for example, when a new type of sheet is set in the paper feed tray 12 and a learning mode start button or the like (not shown) displayed on the display unit is pressed by the user. The sheet type setting screen Sc1 will be described in detail with reference to FIG. 7 described later.

[0030] The cover unit 4 includes an ADF (Auto Document Feeder) unit 41 and an IR (Image Reader) unit 42. The ADF unit 41 reads the document set on the paper feeding unit (not shown) and sends it to the document table (not shown). The IR unit 42 optically reads an image from the document on the document feeding table, performs A / D conversion on the read image, and generates image data (scan data).

[0031] <Configuration of the control system of the image forming apparatus main body> Next, with reference to FIG. 2, the configuration of the control system of the image forming apparatus main body 1 will be described. FIG. 2 is a block diagram showing a configuration example of the control system of the image forming apparatus main body 1.

[0032] As shown in FIG. 2, the image forming apparatus main body 1 includes a control unit 11, a storage unit 13, a communication I / F (Interface) unit 14, an image processing unit 15, an image forming unit 20, a display control unit 16, a sheet type discrimination unit 17, and a threshold correction unit 18.

[0033] The control unit 11 includes a CPU (Central Processing Unit) 111, a RAM (Random Access Memory) 112, and a ROM (Read Only Memory) 113. The CPU 111 reads out various programs such as a system program, an image forming program, and a sheet type discrimination program stored in the ROM 113, expands them in the RAM 112, and controls the operations of each part of the image forming apparatus 100 according to the expanded programs.

[0034] The RAM 112 forms a work area for temporarily storing various programs executed by the CPU 111 and data related to these programs.

[0035] The ROM 113 is composed of a non-volatile memory such as a semiconductor memory, and stores a system program corresponding to the image forming apparatus 100, a sheet image forming program executable on the system program, a type discrimination program, and the like. These programs are stored in the form of program codes readable by a computer, and the CPU 111 sequentially executes operations according to the program codes. That is, the ROM 113 is used as an example of a computer-readable non-transitory recording medium storing a program executed by a computer.

[0036] The storage unit 13 is composed of, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like. The storage unit 13 stores original image data included in a print job, a threshold table T, and the like. The threshold table T is a table in which the type of a sheet is associated with the upper limit value and the lower limit value of the basis weight of the sheet. The threshold table T will be described in detail with reference to FIGS. 4 to 6 described later. Note that the various programs stored in the ROM 113 may be stored in the storage unit 13. That is, the storage unit 13 is also used as an example of a computer-readable non-transitory recording medium storing a program executed by a computer.

[0037] The communication I / F unit 14 controls the transmission and reception operations of various data such as a print job performed between the communication I / F unit 14 and a terminal device (not shown) connected via a network (not shown).

[0038] The image processing unit 15 subjects the original image data included in the print job transmitted from a terminal device (not shown) to RIP (Raster Image Processor) processing to convert it into print image data. Then, the image processing unit 15 performs various image processes on the print image data based on the content of the print settings included in the print job. Since the image forming unit 20 has been described with reference to FIG. 1, the description thereof is omitted here.

[0039] The display control unit 16 controls the display unit of the operation display unit 3 (see FIG. 1) to display various screens such as the sheet type setting screen Sc1 (see FIGS. 7 and 8).

[0040] The sheet type discrimination unit 17 is connected to the basis weight detection sensor 26 via a cable or the like (not shown). Based on the basis weight of the sheet transmitted from the basis weight detection sensor 26, it refers to the threshold table T to discriminate the type of the sheet.

[0041] The threshold correction unit (an example of a condition change unit) 18 performs a threshold correction process when the sheet type associated with the button selected by the user (service technician, user administrator, etc.) via the sheet type setting screen Sc1 (see FIG. 7) is different from the sheet type discriminated by the sheet type discrimination unit 17.

[0042] Specifically, the threshold correction unit 18 calculates the difference between the basis weight detected by the basis weight detection sensor 26 (an example of the first physical property value) used by the sheet type discrimination unit 17 for discriminating the sheet type and the basis weight of the sheet type associated with the button selected by the user (an example of the second physical property value). Then, the threshold correction unit 18 uses the calculated difference as the shift amount to increase or decrease the threshold in the threshold table T (see FIG. 1) in the direction of making the basis weight detected by the basis weight detection sensor 26 coincide with the basis weight of the sheet type associated with the button selected by the user, thereby correcting the threshold.

[0043] Note that the threshold correction unit 18 may change the detection (sensing) condition of the sheet by the basis weight detection sensor 26 instead of the threshold. Alternatively, the threshold correction unit 18 may change the threshold (an example of the second threshold) used when converting the transmitted light L3 or the reflected light L2 (see FIG. 3) detected by the basis weight detection sensor 26 into the basis weight.

[0044] <Configuration of the basis weight detection sensor> Next, with reference to FIG. 3, the configuration of the basis weight detection sensor 26 will be described. FIG. 3 is a diagram showing a configuration example of the basis weight detection sensor 26.

[0045] As shown in FIG. 3, the basis weight detection sensor 26 includes a transmission light source 261a and 261b, a reference plate 262 for the reflection light source, a reflection light source 263, and a light receiving unit 264. The transmission light source 261a is composed of, for example, an LED (Light Emitting Diode) that irradiates near-infrared light, and the transmission light source 261b is composed of an LED or the like that irradiates blue light. The light receiving unit 264 includes a photodiode 264a as a light receiving element.

[0046] The reference plate 262 for the reflection light source is a plate used when correcting the measurement value by the light receiving unit 264. The reflection light source 263 is composed of an LED or the like that irradiates green light. The photodiode 264a receives the transmitted light L3 that is irradiated from the transmission light sources 261a and 261b and passes through the sheet being conveyed on the conveyance path Tp, and the reflected light L2 that is the irradiated light L1 irradiated from the reflection light source 263 and reflected on the sheet. Then, the photodiode 264a measures the transmittance (an example of a physical property value) of the received transmitted light L3 and the reflectance (an example of a physical property value) of the received reflected light L2, and outputs the measurement value to the sheet type determination unit 17 (see FIG. 1).

[0047] In FIG. 3, the transmission light sources 261a and 261b are arranged on the lower side and the reflection light source 263 is arranged on the upper side. Actually, as shown in FIG. 1, for the sheet passing vertically, the transmission light sources 261a and 261b are arranged on the right side and the reflection light source 263 is arranged on the left side.

[0048] As shown in FIG. 1, by arranging the basis weight detection sensor 26 on the upstream side of the resist roller 25, the basis weight detection sensor 26 can detect the basis weight of the sheet in a state where the leading end of the sheet abuts on the nip of the resist roller 25 and the conveyance of the sheet stops.

[0049] <Configuration of Threshold Value> Next, with reference to FIG. 4, the configuration of the threshold value described in the threshold value table T will be described. FIG. 4 is a graph showing an example of the configuration of the threshold value.

[0050] The horizontal axis of the graph shown in Fig. 4 is the nominal basis weight (g / m 2 ), and the vertical axis is the detected basis weight (g / m 2 ) detected by the basis weight detection sensor 26. Of the two thick solid vertical lines shown in the graph, the left vertical line indicates the nominal basis weight lower limit value Thl1, and the right vertical line indicates the nominal basis weight upper limit value Thu1. On the other hand, of the two thick solid horizontal lines shown in the graph, the upper horizontal line indicates the detected basis weight upper limit value Thu2, and the lower horizontal line indicates the detected basis weight lower limit value Thl2. And the rectangular area surrounded by the four solid lines of the nominal basis weight lower limit value Thl1, the nominal basis weight upper limit value Thu1, the detected basis weight upper limit value Thu2, and the detected basis weight lower limit value Thl2 indicates the range of the threshold used for the discrimination of this type of paper.

[0051] Also, of the two dashed horizontal lines shown in the graph, the upper dashed line indicates the detected basis weight variable upper limit value Thvu, and the lower dashed line indicates the detected basis weight variable lower limit value Thvl. When correcting the detected basis weight upper limit value Thu2, it is possible to increase the detected basis weight variable upper limit value Thvu as the maximum value, and when correcting the detected basis weight lower limit value Thl2, it is possible to decrease the detected basis weight variable lower limit value Thvl as the minimum value.

[0052] In this embodiment, the detected basis weight lower limit value Thl2 and the detected basis weight upper limit value Thu2 are set to values corresponding to the upper limit value and the lower limit value of the basis weight classification corresponding to each type of sheet when switching the image forming conditions according to the type of sheet. However, the detected basis weight lower limit value Thl2 and / or the detected basis weight upper limit value Thu2 may be set to arbitrary values by the user according to the user's business form and the like.

[0053] In addition, for the detection basis weight lower limit value Thl2 and / or the detection basis weight upper limit value Thu2, the average value of the detection results of the basis weight of the sheet by the basis weight detection sensor 26 when a plurality of sheets are passed through the image forming apparatus 100 may be set. Alternatively, it may be set to a value considering the standard deviation when the standard deviation is calculated using a plurality of detection results by the basis weight detection sensor 26. For example, the detection basis weight lower limit value Thl2 and / or the detection basis weight upper limit value Thu2 may be set using the detection results with a low standard deviation among the plurality of detection results obtained by the basis weight detection sensor 26.

[0054] <Example of setting the threshold table> Next, with reference to FIG. 5, an example of setting the threshold table T will be described. FIG. 5 is a table showing an example of setting the threshold table T.

[0055] On the left side of the table in FIG. 5, the lower limit value and the upper limit value of the threshold variable range and the sheet type are shown, and on the right side, the lower limit value and the upper limit value of the threshold range of the detected basis weight are shown. FIG. 5 shows examples of the thresholds set for each of the image forming apparatuses 100 for domestic (Japan) destination, US (inch) destination, and European destination. Note that FIG. 5 shows an example in which all the thresholds in Japan, the US, and Europe are displayed in the threshold table T, but in actuality, only the thresholds in the country where the image forming apparatus 100 is shipped shall be displayed.

[0056] For example, in the threshold table T shown in FIG. 5, the lower limit value of the detected basis weight classified as "thin paper" in the sheet type is "58.7 (g / m 2 )" in all of Japan, the US, and Europe, the lower limit value of the threshold variable range is "52 (g / m 2 )", and the upper limit value is "59 (g / m 2 )".

[0057] In addition, the lower limit value of the detected basis weight classified as "plain paper" in the sheet type is shown to be "58.8 (g / m 2 )" in all of Japan, the US, and Europe. The upper limit value of the threshold variable range is "96.2 (g / m 2)” and in the United States it is “98.3 (g / m 2 )” is shown.

[0058] FIG. 6 is a graph showing each threshold value defined in the threshold table T shown in FIG. 5. FIG. 6A is a graph showing an example of a threshold value applied to the Japanese-specification image forming apparatus 100, and FIG. 6B is a graph showing an example of a threshold value applied to the U.S.-specification image forming apparatus 100. FIG. 6C is a graph showing an example of a threshold value applied to the European-specification image forming apparatus 100.

[0059] As shown in the threshold table T shown in FIG. 5, since the threshold value range of the detected basis weight is different for each of the Japanese specification, the U.S. specification, and the European specification, it can be seen that the width and height of the rectangle showing the threshold value range shown in FIG. 6 are also different for each of the Japanese specification, the U.S. specification, and the European specification.

[0060] Returning to FIG. 5 to continue the explanation. The lower limit value of the detected basis weight in the threshold table T shown in FIG. 5 is the detected basis weight lower limit value Thl2 in the graph shown in FIG. 4, and the upper limit value of the detected basis weight is the detected basis weight upper limit value Thu2 in the graph shown in FIG. 4. Also, the lower limit value of the threshold variable range in the threshold table T shown in FIG. 5 is the detected basis weight lower limit value Thl2 in the graph shown in FIG. 4, and the upper limit value of the threshold variable range is the detected basis weight upper limit value Thu2 in the graph shown in FIG. 4.

[0061] For example, when the type of the sheet passed through the Japanese-specification image forming apparatus 100 is “plain paper”, the basis weight detected by the basis weight detection sensor 26 is from the “58.8 (g)” of the detected basis weight lower limit value Thl2 to the detected basis weight upper limit value Thu2 of “96.2 (g / m 2 )”. However, assuming that the detection result of the basis weight detection sensor 26 is “52 (g / m 2 )” which is a value within the threshold value range classified as “thin paper”. In this case, the sheet type determination unit 17 erroneously determines that the type of the sheet is “thin paper”.

[0062] In this embodiment, in such a case, on the sheet type setting screen Sc1 (see FIG. 7), the discrimination result of the sheet type is shown as "thin paper", and other sheet type options are indicated by buttons. Then, the user is prompted to input the correct sheet type.

[0063] <Configuration of the Sheet Type Setting Screen> Next, with reference to FIG. 7, the configuration of the sheet type setting screen Sc1 will be described. FIG. 7 is a diagram showing a configuration example of the sheet type setting screen Sc1. FIG. 7A is a diagram showing a configuration example of the sheet type setting screen Sc1 in which the button indicating the sheet type discriminated by the sheet type discrimination unit 17 is highlighted. FIG. 7B is a diagram showing a configuration example of the sheet type setting screen Sc1 in which the button of the sheet type selected by the user is highlighted.

[0064] As shown in FIGS. 7A and 7B, the sheet type setting screen Sc1 includes a paper type setting button display area Ar1, a basis weight detection result display area Ar2, a basis weight shift amount display area Ar3, a learning mode button Bn1, a start button Bn2, and a stop button Bn3.

[0065] In the paper type setting button display area Ar1, a plurality of buttons showing the names of various paper types (sheet types) of different kinds are displayed. In the example shown in FIG. 7A, the "Thin Paper" button is highlighted. This indicates that the sheet type discriminated by the sheet type discrimination unit 17 is thin paper.

[0066] A user (such as a service technician or user administrator) who is executing the learning mode of the sheet type can select the button with the correct sheet type displayed if the highlighted sheet type is different from the actual sheet type. FIG. 7B shows a state in which the "Plain Paper" button has been pressed by the user. If the highlighted sheet type matches the actual sheet type, the user does not need to reselect the button.

[0067] In the basis weight detection result display area Ar2, the basis weight (g / m 2 ) detected by the basis weight detection sensor 26 (see FIG. 3) is displayed. The user can use the basis weight displayed on the basis weight detection sensor 26 as a judgment material to determine whether the discrimination result by the sheet type discrimination unit 17 is correct or not.

[0068] In the basis weight shift amount display area Ar3, the difference between the basis weight of the sheet of the discriminated sheet type in the discrimination result and the basis weight of the sheet of the sheet type selected by the user is displayed as the basis weight shift amount. The basis weight shift amount to the basis weight shift amount display area Ar3 is displayed when it is determined by the threshold correction unit 18 that the discrimination result by the sheet type discrimination unit 17 and the sheet type corresponding to the button selected by the user are different after the learning mode button Bn1 is pressed.

[0069] In FIGS. 7A and 7B, an example in which both the basis weight detection result display area Ar2 and the basis weight shift amount display area Ar3 are displayed on the sheet type setting screen Sc1 is shown, but the present invention is not limited to this. Either one of the basis weight detection result display area Ar2 and the basis weight shift amount display area Ar3 may be displayed, or neither of them may be displayed.

[0070] The learning mode button Bn1 is a button that, when pressed by the user, starts the calculation and correction process of the difference (shift amount) by the threshold correction unit 18.

[0071] The start button Bn2 is a button that starts a printing job. The stop button Bn3 is a button that ends the learning mode or stops the printing job started based on the pressing of the start button Bn2.

[0072] For example, when the basis weight detected by the basis weight detection sensor 26 is "52 (g / m 2)” is detected, and it is assumed that the sheet type determination unit 17 determines that the sheet type is "thin paper". In this case, as shown in FIG. 7A, the button "Thin Paper" indicating thin paper is highlighted. However, if the actual sheet type is plain paper, the user selects the button "Plain Paper" indicating plain paper as shown in FIG. 7B and then presses the learning mode button Bn1.

[0073] Thereby, the threshold correction unit 18 uses the lower limit value of the detected basis weight of plain paper, which is "58.8 (g / m 2 )" (the lower limit value of the domestic threshold in FIG. 5), and the difference from the detection threshold of "52 (g / m 2 )", which is "6.8 (g / m 2 )", to calculate. Then, the threshold correction unit 18 subtracts the difference of "6.8 (g / m 2 )" as the shift amount from "58.8 (g / m 2 )" and corrects the lower limit value of the detected basis weight of plain paper to the result of the subtraction, which is "52 (g / m 2 )". Based on this correction, the upper limit value of the detection threshold for thin paper is corrected to "51.9 (g / m 2 )".

[0074] In this embodiment, an example is given in which the threshold correction unit 18 corrects the threshold using the difference between the detected basis weight by the basis weight detection sensor 26 and the basis weight associated with the sheet type selected by the user. However, the present invention is not limited to this. For example, the threshold correction unit 18 may correct the threshold using each step obtained by dividing the range indicated by the upper limit value and the lower limit value of the threshold into a predetermined number as the unit of change. Thereby, the threshold correction process by the threshold correction unit 18 can be made simpler.

[0075] <Sheet Type Discrimination Method> Next, a sheet type discrimination method by the image forming apparatus 100 will be described with reference to FIG. 8. FIG. 8 is a flowchart showing an example of the procedure of the sheet type discrimination process by the image forming apparatus 100.

[0076] The sheet discrimination process by the image forming apparatus 100 starts when a user who newly sets a sheet to the paper feed tray 12 (see FIG. 1) presses a learning mode start button (not shown) displayed on the screen of the operation display unit 3.

[0077] First, the control unit 11 (see FIG. 2) of the image forming apparatus 100 detects the pressing of the learning mode start button (step S1). Next, the display control unit 16 causes the operation display unit 3 to display a sheet type setting screen Sc1 (see FIG. 7) (step S2). Next, the control unit 11 feeds a sheet from the paper feed tray 12 and controls to start conveying the sheet in the direction of the registration roller 25 (step S3).

[0078] Next, the basis weight detection sensor 26 that has detected the sheet detects the basis weight of the sheet (step S4). Next, the sheet type discrimination unit 17 discriminates the type of the sheet based on the detected basis weight by the basis weight detection sensor 26 (step S5). Next, the display control unit 16 highlights the button of the type discriminated by the sheet type discrimination unit 17 in step S5 among the paper type setting buttons on the sheet type setting screen Sc1 (step S6).

[0079] Next, the display control unit 16 causes the basis weight detected by the basis weight detection sensor 26 in step S4 to be displayed in the basis weight detection result display area Ar2 (see FIG. 7) of the sheet type setting screen Sc1 (step S7). Next, the control unit 11 determines whether or not the learning mode button Bn1 on the sheet type setting screen Sc1 has been pressed by the user (step S8). If it is determined in step S8 that the learning mode button Bn1 has not been pressed (when step S8 is a NO determination), the control unit 11 continues the determination in step S8.

[0080] On the other hand, in step S8, when it is determined that the learning mode button Bn1 has been pressed (when step S8 is a YES determination), the threshold correction unit 18 determines whether the sheet type selected by the user matches the sheet type determined by the sheet type determination unit 17 (step S9). In step S9, when it is determined that the sheet types match (when step S9 is a YES determination), the sheet type determination process by the image forming apparatus 100 ends. That is, when the sheet type selected by the user matches the sheet type determined by the sheet type determination unit 17, the threshold correction process by the threshold correction unit 18 is not performed.

[0081] On the other hand, in step S9, when it is determined that the sheet types do not match (when step S9 is a NO determination), the threshold correction unit 18 calculates the difference between the detected basis weight by the basis weight detection sensor 26 and the basis weight of the sheet of the sheet type selected by the user (step S10). Next, the threshold correction unit 18 corrects the threshold for sheet type determination using the calculated difference as the shift amount, and stores the corrected threshold in the threshold table T (see FIG. 5) in the storage unit 13 (step S11).

[0082] Next, the control unit 11 sets the sheet type with the corrected threshold as the type of the sheet to be printed (image formed) (step S12). After the process of step S12, the sheet type determination process by the image forming apparatus 100 ends.

[0083] FIG. 9 is a flowchart showing an example of the procedure of the image forming process by the image forming apparatus 100 when the start button Bn2 of the sheet type setting screen Sc1 is pressed.

[0084] First, the control unit 11 (see FIG. 2) of the image forming apparatus 100 sets the set value of the process control (image forming conditions) based on the determination result of the sheet type determination process shown in FIG. 8 (step S21). That is, various set values corresponding to sheet types such as "thin paper" and "plain paper" are set.

[0085] Next, the control unit 11 of the image forming apparatus 100 starts an image forming operation based on process control (step S22). Next, the sheet on which the image has been formed is discharged from the paper output tray 27 (see FIG. 1) (step S23). After the process of step S23, the image forming process by the image forming apparatus 100 ends.

[0086] In the above-described embodiment, when the type of the sheet input via the sheet type setting screen Sc1 is different from the type of the sheet determined by the sheet type determination unit 17, the threshold correction unit 18 calculates the difference between the physical property value detected by the basis weight detection sensor 26 and the physical property value associated with the input sheet, and corrects the condition using the difference as the shift amount. Therefore, according to the present embodiment, the condition used for determining the type of the sheet can be more appropriately corrected without having the user specify the correction amount.

[0087] <Various Modification Examples> Note that the present invention is not limited to the above-described embodiment, and various other application examples and modification examples can be adopted without departing from the gist of the present invention described in the claims.

[0088] For example, the threshold value used by the sheet type determination unit 17 for determining the sheet may be set to a value that allows for variations in the sheet and / or variations in the basis weight detection sensor 26. By performing such processing, even when there are large variations in the sheets set in the paper feed tray 12 or when there are large variations in the basis weight detection sensor 26, the sheet type determination unit 17 can appropriately determine the sheet type.

[0089] Alternatively, the threshold value may be set based on the detected basis weight detected by the basis weight detection sensor 26 after calibration capable of eliminating variations in the basis weight detection sensor 26. By performing such processing, even when there are large variations in the basis weight detection sensor 26, the sheet type determination unit 17 can appropriately determine the sheet type.

[0090] Further, the threshold correction unit 18 may correct the threshold using the basis weight selected based on the average value of the basis weights of the sheets detected a plurality of predetermined times by the basis weight detection sensor 26 and / or the information on the standard deviation calculated based on the physical property values of the sheets detected a plurality of times. By performing such processing, even when there are large variations in the sheets set in the paper feed tray 12 or when there are large variations in the basis weight detection sensor 26, the sheet type determination unit 17 can appropriately determine the sheet type.

[0091] When performing threshold correction using the information on the standard deviation, the threshold correction unit 18 may perform control to increase or decrease the number of times of detecting the basis weight of the sheet by the basis weight detection sensor 26 according to the magnitude of the standard deviation. The standard deviation calculated based on the physical property values of the sheets detected a plurality of times tends to become smaller as the number of times of detecting the basis weight of the sheet by the basis weight detection sensor 26 increases. Therefore, the standard deviation can be reduced by increasing the number of times of detecting the basis weight of the sheet by the basis weight detection sensor 26. Also, when the standard deviation is small, it becomes possible to save the time and resources required for learning the sheet type by performing control to decrease the number of times of detecting the basis weight of the sheet by the basis weight detection sensor 26.

[0092] Further, when the detected basis weight by the basis weight detection sensor 26 is an outlier of the standard deviation, the threshold correction unit 18 may not perform threshold correction using the basis weight of the outlier. When the detected basis weight by the basis weight detection sensor 26 becomes an outlier of the standard deviation, a failure of the basis weight detection sensor 26 or the like is also assumed. Therefore, control not to correct the threshold may be performed in such a case. At this time, the display control unit 16 may notify the user via the screen of the operation display unit 3, a speaker (not shown), or the like that the detected basis weight by the basis weight detection sensor 26 is an outlier of the standard deviation, to stop the execution of the learning mode, and to prompt an inspection of the basis weight detection sensor 26.

[0093] Also, for example, when a print job is input during the execution of the learning mode (during the execution of the threshold correction process by the threshold correction unit 18), the control unit 11 may instruct the sheet type discrimination unit 17 to discriminate the type of sheet based on the print job using the threshold value after the correction by the threshold correction unit 18. By performing such control, it becomes possible to realize appropriate image formation based on the discrimination result of the sheet using the appropriate threshold value after correction.

[0094] Also, when a print job is input during the execution of the learning mode (during the execution of the threshold correction process by the threshold correction unit 18), and there is a paper feed tray 12 that stores sheets of the same type as the sheet targeted for threshold correction and for which the correction by the threshold correction unit 18 has been completed, the control unit 11 may perform discrimination of the type of sheet for the sheets fed from the paper feed tray 12. By performing such control, even when a print job is input during the execution of the learning mode, printing can be performed without stopping the print job, so there is no need to keep the user waiting.

[0095] Also, the control unit 11 may detect the attribute information of the user who operates on the sheet type setting screen Sc1, and when the detected user attribute is an operator, perform control to notify a service technician or user administrator that the threshold has been corrected based on the operator's operation. By performing such control, for example, service technicians, user administrators, etc. can determine whether appropriate processing has been performed by the operator.

[0096] Also, after the threshold correction by the threshold correction unit 18, the control unit 11 may perform control to notify the user via the screen of the operation display unit 3 or a speaker (not shown) etc. to prompt the passage of a new sheet for the purpose of confirming whether or not the discrimination result of the type of sheet using the corrected threshold value is correct.

[0097] Also, in the above-described embodiment, an example was given in which the correct sheet type is input by a user's operation on the sheet type setting screen Sc1, but the present invention is not limited to this. The correct sheet type may be input by voice by the user to a microphone (not shown).

[0098] Also, in the above-described embodiment, an example was given in which the sheet that is fed into the paper feed tray 12 is paper (printing paper), but the present invention is not limited to this. The sheet may be made of a material other than paper.

[0099] Furthermore, in the above-described embodiment, an example was given in which the sheet type discrimination device is applied to the image forming apparatus 100, but the present invention is not limited to this. The sheet type discrimination device of the present invention may be applied to a terminal device or a server that does not perform image formation.

Explanation of Reference Numerals

[0100] 1... Image forming apparatus main body, 2... Paper feed cabinet section, 3... Operation display section, 11... Control section, 12... Paper feed tray, 13... Storage section, 16... Display control section, 17... Sheet type discrimination section, 18... Threshold correction section, 20... Image forming section, 25... Registration roller, 26... Basis weight detection sensor, 100... Image forming apparatus

Claims

1. A physical property value detection unit that detects the physical property values of a sheet; A sheet type determination unit that determines the type of the sheet based on the physical property values of the sheet detected by the physical property value detection unit and a predetermined condition indicated by the physical property values; An input unit to which information on the type of the sheet is input; When the type of the sheet input to the input unit is different from the type of the sheet determined by the sheet type determination unit, a difference between a first physical property value of the sheet detected by the physical property value detection unit and a second physical property value associated with the sheet input to the input unit is calculated, and a condition change unit that corrects the condition using the difference as a shift amount; and The condition is a threshold value that classifies the type of the sheet; The physical property value detection unit converts the detected physical property value into basis weight and outputs it; The threshold value is indicated by an upper limit value and a lower limit value of the basis weight of the sheet; The condition change unit corrects the threshold value by increasing or decreasing the threshold value by the amount of the shift in a direction to match the first physical property value with the second physical property value; Further comprising a display control unit that causes a display unit to display a sheet type setting screen on which information on the types of a plurality of sheets including the information on the type of the sheet determined by the sheet type determination unit is displayed in a selectable form; The type of the sheet selected on the sheet type setting screen is input to the input unit; The upper limit value and the lower limit value of the threshold value are set to values that allow for variations in the sheet or variations in the physical property value detection unit; The condition change unit corrects the threshold value using each step obtained by dividing the range indicated by the upper limit value and the lower limit value of the threshold value by a predetermined number as a unit of change; A sheet type determination device.

2. The display control unit causes the type of the sheet determined by the sheet type determination unit to be highlighted on the sheet type setting screen; The sheet type determination device according to claim 1.

3. The display control unit causes the basis weight of the sheet detected by the physical property value detection unit and / or the shift amount to be displayed on the sheet type setting screen; The sheet type determination device according to claim 1.

4. The threshold value is set based on the physical property values detected by the physical property value detection unit after calibration capable of eliminating variations in the physical property value detection unit; The sheet type determination device according to claim 1.

5. The condition changing unit corrects the threshold value using the physical property value selected based on the average value of the physical property values of the sheet detected a predetermined number of times by the physical property value detecting unit, or the information on the standard deviation calculated based on the physical property values of the sheet detected a plurality of times. The sheet type discrimination device according to claim 1 or 4.

6. The condition changing unit performs control to increase or decrease the number of times the sheet is detected by the physical property value detecting unit according to the magnitude of the standard deviation calculated based on the physical property values of the sheet detected a plurality of times. The sheet type discrimination device according to claim 5.

7. When a print job is input during the execution of the threshold correction process by the condition changing unit, the sheet type discrimination unit is further provided with a control unit that instructs the sheet type discrimination unit to perform discrimination of the type of the sheet based on the print job using the threshold value after the correction by the condition changing unit. The sheet type discrimination device according to claim 1 or 4.

8. When a print job is input during the execution of the threshold correction process by the condition changing unit, and there is a paper feed tray storing the sheet of the same type as the sheet targeted for the threshold correction and for which the correction by the condition changing unit has been completed, the sheet type discrimination unit is further provided with a control unit that instructs the sheet type discrimination unit to perform discrimination of the type of the sheet fed from the paper feed tray. The sheet type discrimination device according to claim 1 or 4.

9. The sheet type discrimination device further includes a control unit that detects attribute information of a user who operates on the sheet type setting screen. When the attribute of the user detected by the control unit is an operator, the control unit performs control to notify a maintenance person or a user administrator that the threshold value has been corrected based on the operation of the user. The sheet type discrimination device according to claim 1.

10. After the threshold value is corrected by the condition changing unit, the sheet type discrimination device further includes a control unit that issues a notification prompting the passage of a new sheet for the purpose of confirming whether the discrimination result of the type of the sheet using the corrected threshold value is correct. The sheet type discrimination device according to claim 1.

11. The condition changed by the condition changing unit is the detection condition of the sheet by the physical property value detecting unit. The sheet type discrimination device according to claim 1.

12. The condition changed by the condition changing unit is a second threshold value used when converting the physical property value detected by the physical property value detecting unit into the basis weight. The sheet type discrimination device according to claim 1.

13. The input unit is a voice input unit that collects voice, and the type of the sheet is input by voice. The sheet type discrimination device according to claim 1.

14. A procedure in which a physical property value detecting unit detects a physical property value of a sheet, A procedure in which a sheet type discrimination unit discriminates the type of the sheet based on the detected physical property value of the sheet and a predetermined condition indicated by the physical property value, A procedure in which information on the type of the sheet is input to the input unit, When the input type of the sheet is different from the discriminated type of the sheet, a difference between the first physical property value of the detected sheet and the second physical property value associated with the input sheet is calculated, and the condition changing unit corrects the condition using the difference as a shift amount. The condition is a threshold value for classifying the type of the sheet. The physical property value detecting unit converts the detected physical property value into the basis weight and outputs it. The threshold value is indicated by the upper limit value and the lower limit value of the basis weight of the sheet. The condition changing unit corrects the threshold value by increasing or decreasing the threshold value by the amount of the shift in the direction of matching the first physical property value with the second physical property value. The sheet type discrimination device further includes a display control unit that causes a display unit to display a sheet type setting screen on which information on the types of a plurality of sheets including the information on the type of the sheet discriminated by the sheet type discrimination unit is displayed in a selectable form. The type of the sheet selected on the sheet type setting screen is input to the input unit. The upper limit value and the lower limit value of the threshold value are set to values that allow for variations in the sheet or variations in the physical property value detecting unit. The condition changing unit corrects the threshold value using each step obtained by dividing the range indicated by the upper limit value and the lower limit value of the threshold value by a predetermined number as a unit of change. Sheet type discrimination method.

Images