Image forming apparatus, medium type detection method, and medium type detection program

Abstract

To shorten the time from when a recording medium is conveyed to when an image is formed.SOLUTION: An image forming apparatus comprises: a plurality of sheet feed trays that store recording media; a detection control unit 71 that detects a physical property value indicating a physical property of a recording medium; an association unit 81 that associates a type of the recording medium corresponding to the detected physical property value with the sheet feed tray storing the recording medium being the detection target among the plurality of sheet feed trays; and an image forming control unit 77 that forms an image on the recording medium using parameters corresponding to the type of the recording medium. The detection control unit 71 detects the physical property value of the recording medium stored in the sheet feed tray that is not associated with the type by the association unit 81 during a non-printing period in which no image is formed on the recording medium.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, a medium type detection method, and a medium type detection program, and more particularly to an image forming apparatus that forms an image on a recording medium according to the type of the recording medium, a medium type detection method executed by the image forming apparatus, and a medium type detection program that causes a computer to execute the medium type detection method.

Background Art

[0002] In an image forming apparatus such as an MFP (Multi Function Peripheral), a recording medium is taken out one by one from a paper feed tray in which a plurality of recording media are accommodated, conveyed, and an image is formed on the conveyed recording medium. In this MFP, in order to improve the image quality of the image formed on the recording medium, the conditions for forming the image are made different according to the type of the recording medium.

[0003] For example, Japanese Patent Application Laid-Open No. 2013-7961 discloses a first detection means for detecting information on a first characteristic of a recording material, a second detection means for detecting information on a second characteristic of the recording material, an image forming means for forming an image on the recording material, and a control means for controlling the image forming conditions of the image forming means. When one of the first characteristic and the second characteristic is detected, the control means starts controlling the image forming conditions of the image forming means based on the detected characteristic. An image forming apparatus is described.

[0004] The type of the recording medium needs to be set before forming an image. The MFP may change the image forming speed depending on the type of the recording medium. When detecting the type of the recording medium while conveying it, it is necessary to set the conveying speed relatively slow in order to accurately convey the type of the recording medium. For this reason, even for a type of recording medium that can form an image at a relatively high conveying speed, it has to be conveyed at a relatively low conveying speed in order to detect its type, resulting in a problem that the time for forming an image becomes longer.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-7961 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] This invention has been made to solve the above-described problems, and one of the objects of this invention is to provide an image forming apparatus capable of shortening the time from when a recording medium is conveyed until an image is formed.

[0007] Another object of this invention is to provide a medium type detection method capable of shortening the time from when a recording medium is conveyed until an image is formed.

[0008] Still another object of this invention is to provide a medium type detection program capable of shortening the time from when a recording medium is conveyed until an image is formed. [Means for Solving the Problems]

[0009] This invention has been made to solve the above-described problems, and according to an aspect of this invention, an image forming apparatus includes a plurality of paper feed trays for accommodating recording media, a detection means for detecting a physical property value indicating the physical properties of a recording medium, an association means for associating the type of the recording medium corresponding to the detected physical property value with the paper feed tray in which the recording medium that is the object of detection by the detection means among the plurality of paper feed trays is accommodated, and an image forming means for forming an image on the recording medium using parameters for the type of the recording medium. The detection means detects the physical property value of a recording medium accommodated in a paper feed tray whose type is not associated by the association means during a non-printing period in which no image is formed on the recording medium by the image forming means.

[0010] According to another aspect of the present invention, a medium type detection method is a medium type detection method executed by an image forming apparatus. The image forming apparatus includes a plurality of paper feed trays for accommodating a recording medium and an image forming unit for forming an image on the recording medium. The method includes a detection step of detecting a physical property value indicating a physical property of the recording medium, an association step of associating the type of the recording medium corresponding to the detected physical property value with the paper feed tray in which the recording medium that was the object of detection by the detection unit among the plurality of paper feed trays is accommodated, and an image forming control step of causing the image forming unit to form an image using parameters for the type of the recording medium. The detection step includes a step of detecting the physical property value of the recording medium accommodated in the paper feed tray that has not been associated with a type in the association step during a non-printing period when no image is being formed on the recording medium by the image forming unit.

[0011] According to another aspect of the present invention, a medium type detection program is a medium type detection program executed by a computer that controls an image forming apparatus. The image forming apparatus includes a plurality of paper feed trays for accommodating a recording medium and an image forming unit for forming an image on the recording medium. The program causes the computer to execute a detection step of detecting a physical property value indicating a physical property of the recording medium, an association step of associating the type of the recording medium corresponding to the detected physical property value with the paper feed tray in which the recording medium that was the object of detection by the detection unit among the plurality of paper feed trays is accommodated, and an image forming control step of causing the image forming unit to form an image using parameters for the type of the recording medium. The detection step includes a step of detecting the physical property value of the recording medium accommodated in the paper feed tray that has not been associated with a type in the association step during a non-printing period when no image is being formed on the recording medium by the image forming unit.

Brief Description of the Drawings

[0012]

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Embodiments for Carrying Out the Invention

[0013] Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. Further, in the following description, an MFP will be described as an example of the image forming apparatus. Furthermore, in the MFP described below, as a recording medium for forming an image, paper such as plain paper, high-quality paper, recycled paper, or photographic paper, or superimposed paper in a state where two sheets of paper are superimposed like an envelope is used.

[0014] FIG. 1 is a perspective view showing the appearance of the MFP in the present embodiment. FIG. 2 is a block diagram showing an outline of the hardware configuration of the MFP. Referring to FIGS. 1 and 2, the MFP 100 is an example of an image forming apparatus, and includes a main circuit 110, an original reading unit 130 for reading an original, an automatic document feeder 120 for conveying the original to the original reading unit 130, an image forming unit 140 for forming an image on a recording medium based on image data, a paper feeding unit 150 for supplying the recording medium to the image forming unit 140, a post-processing device 155, and an operation panel 160 as a user interface.

[0015] The automatic document feeder 120 automatically conveys a plurality of documents set on the document tray 125 one by one to the document reading position of the document reading unit 130, and discharges the document from which the image formed on the document has been read by the document reading unit 130 onto the document discharge tray 127. The automatic document feeder 120 includes a document detection sensor that detects a document placed on the document tray 125.

[0016] The document reading unit 130 has a rectangular reading surface for reading documents. The reading surface is formed of, for example, a platen glass. The automatic document feeder 120 is connected to the main body of the MFP 100 so as to be rotatable about an axis parallel to one side of the reading surface, and is openable and closable. The document reading unit 130 is disposed below the automatic document feeder 120, and the reading surface of the document reading unit 130 is exposed in the open state where the automatic document feeder 120 is rotated and opened. Therefore, the user can place a document on the reading surface of the document reading unit 130. The automatic document feeder 120 can change its state between an open state in which the reading surface of the document reading unit 130 is exposed and a closed state in which the reading surface is covered. The automatic document feeder 120 includes a state detection sensor that detects the open state of the automatic document feeder 120.

[0017] The document reading unit 130 includes a light source that irradiates light and a photoelectric conversion element that receives light, and scans an image formed on a document placed on the reading surface. When a document is placed in the reading area, the light irradiated from the light source is reflected by the document, and the reflected light forms an image on the photoelectric conversion element. When the photoelectric conversion element receives the light reflected by the document, it generates image data obtained by converting the received light into an electrical signal. The document reading unit 130 outputs the image data to the CPU 111 provided in the main circuit 110.

[0018] The paper feeding unit 150 takes out a recording medium stored in the first to third paper feeding trays 151 to 153 (FIG. 3) described later, and conveys it as an object to be conveyed to the image forming unit 140.

[0019] The image forming unit 140 is controlled by the CPU 111 and forms an image on an object to be conveyed by the paper feeding unit 150 according to a well-known electrophotographic method. In the present embodiment, the image forming unit 140 forms the image of the image data input from the CPU 111 on the object to be conveyed by the paper feeding unit 150. The object on which the image is formed is discharged to the post-processing device 155. The image data output from the CPU 111 to the image forming unit 140 includes, in addition to the image data input from the original document reading unit 130, image data such as print data received from the outside.

[0020] The post-processing device 155 receives the paper on which the image is formed by the image forming unit 140 and performs post-processing on the paper. The post-processing device 155 has a plurality of paper discharge trays and discharges the paper received from the image forming unit 140 to any one of the plurality of paper discharge trays. The post-processing device 155 performs, but is not limited to, a process of sorting a plurality of papers by conveying the plurality of papers to any one of the plurality of paper discharge trays, a process of punching holes in the paper, and a process of driving staple pins into the paper.

[0021] The main circuit 110 includes a CPU (Central Processing Unit) 111 that controls the entire MFP 100, a communication interface (I / F) unit 112, a ROM (Read Only Memory) 113, a RAM (Random Access Memory) 114, a hard disk drive (HDD) 115 as a mass storage device, a facsimile unit 116, and an external storage device 118. The CPU 111 is connected to the automatic document feeder 120, the original document reading unit 130, the image forming unit 140, the paper feeding unit 150, the post-processing device 155, and the operation panel 160, and controls the entire MFP 100.

[0022] The ROM 113 stores a program executed by the CPU 111 or data necessary for executing the program. The RAM 114 is used as a work area when the CPU 111 executes a program. Further, the RAM 114 temporarily stores the image data continuously sent from the original document reading unit 130.

[0023] The operation panel 160 is provided at the upper part of the MFP 100. The operation panel 160 includes a display unit 161 and an operation unit 163. The display unit 161 is, for example, a liquid crystal display device (LCD), and displays an instruction menu for the user, information on the acquired image data, and the like. Note that instead of the LCD, for example, an organic EL (electroluminescence) display can be used as long as it is a device that can display an image.

[0024] The operation unit 163 includes a touch panel 165 and a hard key unit 167. The touch panel 165 is a capacitance type. Note that the touch panel 165 is not limited to the capacitance type, and for example, other types such as a resistive film type, a surface acoustic wave type, an infrared type, and an electromagnetic induction type can be used.

[0025] The touch panel 165 is provided such that its detection surface overlaps with and is provided on the upper surface or the lower surface of the display unit 161. Here, the size of the detection surface of the touch panel 165 is the same as the size of the display surface of the display unit 161. For this reason, the coordinate system of the display surface and the coordinate system of the detection surface are the same. The touch panel 165 detects the position where the user indicates the display surface of the display unit 161 on the detection surface, and outputs the coordinates of the detected position to the CPU 111. Since the coordinate system of the display surface and the coordinate system of the detection surface are the same, the coordinates output by the touch panel 165 can be replaced with the coordinates of the display surface.

[0026] The hard key unit 167 includes a plurality of hard keys. The hard keys are, for example, contact switches. The touch panel 165 detects the position indicated by the user in the display surface of the display unit 161. Since the user is often in an upright posture when operating the MFP 100, the display surface of the display unit 161, the operation surface of the touch panel 165, and the hard key unit 167 are arranged facing upward. This is to enable the user to easily visually recognize the display surface of the display unit 161 and to easily indicate the operation unit 163 with a finger.

[0027] The communication I / F unit 112 is an interface for connecting the MFP 100 to a network. The communication I / F unit 112 communicates with other computers or data processing devices connected to the network using a communication protocol such as TCP (Transmission Control Protocol) or FTP (File Transfer Protocol). Note that the network to which the communication I / F unit 112 is connected is a local area network (LAN), and the connection form may be wired or wireless. Also, the network is not limited to a LAN, and may be a wide area network (WAN), a public switched telephone network (PSTN), the Internet, or the like.

[0028] The facsimile unit 116 is connected to a public switched telephone network (PSTN), and transmits facsimile data to the PSTN or receives facsimile data from the PSTN. The facsimile unit 116 stores the received facsimile data in the HDD 115, and also converts it into printable print data by the image forming unit 140 and outputs it to the image forming unit 140. Thereby, the image forming unit 140 forms an image of the facsimile data received by the facsimile unit 116 on paper. Also, the facsimile unit 116 converts the data stored in the HDD 115 into facsimile data and transmits it to a facsimile apparatus connected to the PSTN.

[0029] The external storage device 118 is controlled by the CPU 111, and a CD-ROM (Compact Disk Read Only Memory) 118A or a semiconductor memory is attached. In the present embodiment, an example in which the CPU 111 executes a program stored in the ROM 113 will be described. However, the CPU 111 may control the external storage device 118 to read out a program for the CPU 111 to execute from the CD-ROM 118A, store the read program in the RAM 114, and execute it.

[0030] Note that the recording medium for storing the program to be executed by the CPU 111 is not limited to the CD-ROM 118A, and media such as flexible disks, cassette tapes, optical disks (MO (Magnetic Optical Disc) / MD (Mini Disc) / DVD (Digital Versatile Disc)), IC cards, optical cards, mask ROMs, and semiconductor memories such as EPROM (Erasable Programmable ROM) may also be used. Further, the CPU 111 may download a program from a computer connected to a network and store it in the HDD 115, or a computer connected to the network may write the program to the HDD 115, and then load the program stored in the HDD 115 into the RAM 114 and execute it with the CPU 111. The program referred to here includes not only programs directly executable by the CPU 111, but also source programs, compressed programs, encrypted programs, and the like.

[0031] FIG. 3 is a schematic side view showing an internal configuration of a part of the image forming unit and the paper feeding unit. Referring to FIG. 3, inside the MFP 100, a main conveyance path 41 indicated by a thick dotted line is formed so as to basically extend in the vertical direction. The main conveyance path 41 is a path for guiding the paper conveyed from the paper feeding unit 150 through the image forming unit 140 to the post-processing device 155. In the main conveyance path 41 of this example, a lower end portion 30 on the opposite side of the upper end portion 13 located above the image forming unit 140 constitutes an entrance for receiving the paper from the paper feeding unit 150. Also, the upper end portion 13 of the main conveyance path 41 constitutes an outlet for discharging the paper after image formation to the post-processing device 155. A paper discharge roller 15 is provided at the upper end portion 13 of the main conveyance path 41. The lower end portion 30 of the main conveyance path 41 is connected to a plurality of sub-conveyance paths SP1, SP2, SP3 of the paper feeding unit 150 described later.

[0032] The paper feeding unit 150 includes three paper feeding trays 151, 152, and 153. The three paper feeding trays 151, 152, and 153 are stacked and arranged so as to be aligned from above to below in this order. As shown by the thick dashed line in Fig. 3, in the paper feeding unit 150, a sub-conveying path SP1 extending from the paper feeding tray 151 located at the upper stage among the three paper feeding trays 151, 152, and 153 to the lower end portion 30 of the main conveying path 41 is formed. Further, two sub-conveying paths 152a and 153a extending from the paper feeding trays 152 and 153 located at the middle and lower stages among the three paper feeding trays 151, 152, and 153 to the lower end portion 30 of the main conveying path 41 are formed. A portion of a predetermined length from the lower end portion 30 of the main conveying path 41 of each of the two sub-conveying paths 152a and 153a is a sub-conveying path SP3 shared by the two sub-conveying paths 152a and 153a.

[0033] Corresponding to the paper feeding tray 151, a pickup roller 151p and a paper feeding roller 151r are provided. The paper feeding roller 151r is provided on the sub-conveying path SP1. Corresponding to the paper feeding tray 152, a pickup roller 152p and a paper feeding roller 152r are provided. The paper feeding roller 152r is provided on the sub-conveying path 152a. Corresponding to the paper feeding tray 153, a pickup roller 153p and a paper feeding roller 153r are provided. The paper feeding roller 153r is provided on the sub-conveying path 153a. Since the operations of taking out and conveying the recording medium from each of the paper feeding trays 151, 152, and 153 are the same, here, the paper feeding tray 151 will be described as an example.

[0034] The paper feed tray 151 stores one or more recording media in a stacked state. The paper feed tray 151 has a lift-up mechanism that pushes up one or more recording media stored therein upward. The pickup roller 151p is biased downward by an elastic member such as a spring in a state of abutting against the uppermost recording medium of one or more recording media stored in the paper feed tray 151 from above. The pickup roller 151p presses from above the recording medium. When the pickup roller 151p rotates, the uppermost recording medium is sent out to the sub-conveying path SP1 by the frictional force between the recording medium and the pickup roller 151p. The recording medium sent out to the sub-conveying path SP1 is supplied to the main conveying path 41 by the paper feed roller 151r as an object to be conveyed. Hereinafter, the recording medium sent out to the sub-conveying path SP1 by the pickup roller 151p and conveyed by the paper feed roller 151r is referred to as an object to be conveyed.

[0035] By the rotation of the pickup roller 151p, the uppermost recording medium of one or more recording media stored in the paper feed tray 151 is sent out to the sub-conveying path SP1 by the friction with the pickup roller 151p. In this case, the second recording medium overlapping the uppermost recording medium receives a frictional force from the uppermost recording medium, but the second recording medium receives a frictional force from the third recording medium overlapping it on the lower side. Therefore, the force biasing the pickup roller 151p is adjusted so that only the uppermost recording medium is sent out to the sub-conveying path SP1.

[0036] In the MFP 100, at the time of image formation, the tray in which the recording medium to be image-formed is stored is selected as the target tray from among the three paper feed trays 151, 152, and 153. The pickup roller and the paper feed roller corresponding to the tray selected as the target tray among the three paper feed trays 151, 152, and 153 operate. Thereby, the object to be conveyed is supplied from the tray selected as the target tray to the main conveying path 41 through either the sub-conveying path SP1 or SP3.

[0037] The image forming unit 140 includes image forming units 51Y, 51M, 51C, and 51K for yellow, magenta, cyan, and black respectively. When at least one of the image forming units 51Y, 51M, 51C, and 51K is driven, an image is formed on the object to be conveyed. When all of the image forming units 51Y, 51M, 51C, and 51K are driven, a full-color image is formed. Printing data for yellow, magenta, cyan, and black are input into the image forming units 51Y, 51M, 51C, and 51K respectively. Since the image forming units 51Y, 51M, 51C, and 51K only differ in the color of the toner they handle, here, the image forming unit 51Y for forming a yellow image will be described.

[0038] The image forming unit 51Y includes an exposure head into which yellow printing data is input, a photosensitive drum (image carrier), a charging charger, a developing device, and a transfer roller 53Y. The exposure head emits laser light according to the received printing data (electrical signal). The emitted laser light is one-dimensionally scanned by a polygon mirror included in the exposure head to expose the photosensitive drum. The direction in which the photosensitive drum is one-dimensionally scanned is the main scanning direction. The photosensitive drum is charged by the charging charger and then irradiated with the laser light emitted by the exposure head. Thereby, an electrostatic latent image is formed on the photosensitive drum. Subsequently, toner is placed on the electrostatic latent image by the developing device to form a toner image. The toner image formed on the photosensitive drum is transferred onto the intermediate transfer belt 57 by the transfer roller 53Y.

[0039] On the other hand, the intermediate transfer belt 57 is suspended by the driving roller 54 and the roller 54A so as not to slacken. When the driving roller 54 rotates counterclockwise in the figure, the intermediate transfer belt 57 rotates counterclockwise in the figure at a predetermined speed. As the intermediate transfer belt 57 rotates, the roller 54A rotates counterclockwise.

[0040] As a result, the image forming units 51Y, 51M, 51C, and 51K transfer toner images onto the intermediate transfer belt 57 in order. The timing at which each of the image forming units 51Y, 51M, 51C, and 51K transfers a toner image onto the intermediate transfer belt 57 is adjusted by detecting a reference mark attached to the intermediate transfer belt 57. As a result, yellow, magenta, cyan, and black toner images are superimposed on the intermediate transfer belt 57.

[0041] On the main conveyance path 41 described above, a timing roller 45, a transfer roller 47, a fixing roller 49, and a paper discharge roller 15 are arranged at intervals in this order from the lower end portion 30 to the upper end portion 13. An object to be conveyed supplied from the paper feeding unit 150 to the main conveyance path 41 is sent to the timing roller 45.

[0042] The timing roller 45 adjusts the conveyance state of the object to be conveyed in the main conveyance path 41 so that the object to be conveyed reaches the transfer roller 47 at the timing when the toner image formed on the intermediate transfer belt 57 reaches the transfer roller 47. The object to be conveyed conveyed by the timing roller 45 is pressed against the intermediate transfer belt 57 by the transfer roller 47. By charging the transfer roller 47, yellow, magenta, cyan, and black toner images formed superimposed on the intermediate transfer belt 57 are transferred to the object to be conveyed. The voltage applied to the transfer roller 47 is controlled by the CPU 111 so that the charge amount of the transfer roller 47 becomes a value suitable for the basis weight of the object to be conveyed.

[0043] The object to be conveyed onto which the toner image has been transferred is conveyed to the fixing roller 49 and heated by the fixing roller 49. As a result, the toner is melted and fixed to the object to be conveyed. Thereafter, the object to be conveyed after image formation is discharged onto the paper discharge tray 159 from the upper end portion 13 of the main conveyance path 41 by the paper discharge roller 15. The temperature of the fixing roller 49 is controlled by the CPU 111 so that it becomes a value suitable for the basis weight of the object to be conveyed.

[0044] In the MFP 100 according to the present embodiment, an optical sensor 61, an ultrasonic sensor 63, and a pressure sensor 65 having a detection area are provided in the main conveyance path 41.

[0045] The optical sensor 61 includes a transmissive sensor and a reflective sensor. The transmissive optical sensor 61 includes a light emitting unit and a light receiving unit and is disposed between the lower end portion 30 of the main conveyance path 41 and the timing roller 45. The transmissive optical sensor 61 is disposed such that the light emitting unit and the light receiving unit face each other with the main conveyance path 41 therebetween. An object to be conveyed is detected in the region within the main conveyance path 41 between the light emitting unit and the light receiving unit. The transmissive optical sensor 61 outputs a value indicating the light transmittance. The transmittance indicates the ratio of the amount of light received by the light receiving unit to the amount of light output by the light emitting unit. The light transmittance varies depending on the basis weight of the paper, and there is a predetermined relationship between the light transmittance and the basis weight of the paper. The higher the basis weight of the paper, the lower the light transmittance. Therefore, by obtaining the relationship between the basis weight of the paper and the light transmittance through experiments or the like, the basis weight of the paper is determined from the light transmittance.

[0046] Also, the reflective optical sensor 61 includes a light emitting unit and a light receiving unit and is disposed between the lower end portion 30 of the main conveyance path 41 and the timing roller 45. The reflective optical sensor 61 is disposed such that the light emitting unit and the light receiving unit are disposed on one side of the main conveyance path 41. The reflective optical sensor 61 outputs a value indicating the light reflectance. The reflectance indicates the ratio of the amount of light received by the light receiving unit to the amount of light output by the light emitting unit. The light reflectance varies depending on the state of the surface of the paper, and there is a predetermined relationship between the light reflectance and the color of the surface of the paper. The whiter the surface of the paper, the higher the light reflectance. Therefore, by obtaining the relationship between the whiteness of the paper and the light reflectance through experiments or the like, the whiteness of the paper is determined from the light reflectance.

[0047] The ultrasonic sensor 63 includes an ultrasonic transmitting unit and an ultrasonic receiving unit, and is of a transmission type. The ultrasonic sensor 63 is disposed at a position downstream of the optical sensor 61 at a position between the lower end portion 30 of the main conveyance path 41 and the timing roller 45. The ultrasonic transmitting unit and the ultrasonic receiving unit are arranged so as to face each other with the main conveyance path 41 interposed therebetween. The ultrasonic transmitting unit includes a piezoelectric element and a drive circuit for the piezoelectric element, and transmits ultrasonic waves. The ultrasonic receiving unit includes a piezoelectric element and a detection circuit for detecting the electromotive force generated in the piezoelectric element, and detects the electromotive force generated in the piezoelectric element by the ultrasonic waves transmitted from the ultrasonic transmitting unit. The region in the main conveyance path 41 between the ultrasonic transmitting unit and the ultrasonic receiving unit serves as a detection region.

[0048] The ultrasonic sensor 63 outputs a value indicating the attenuation amount of ultrasonic waves. The value indicating the attenuation amount of ultrasonic waves is here referred to as the attenuation rate. There is a significant difference in the attenuation rate of ultrasonic waves between the sheet and the superimposed sheets. This is due to the fact that the superimposed sheets have two sheets overlapping. When two sheets overlap, there is a gap between the two sheets, so the attenuation rate of ultrasonic waves by the superimposed sheets is significantly smaller than the attenuation rate of ultrasonic waves by a single sheet. Therefore, the presence or absence of the overlap of two sheets can be detected from the attenuation rate of ultrasonic waves. Also, the attenuation rate indicates the ratio of the volume of ultrasonic waves transmitted through the object to be conveyed to the volume of the ultrasonic waves transmitted. The attenuation rate of ultrasonic waves varies depending on the basis weight of the sheet, and there is a predetermined relationship between the attenuation rate of ultrasonic waves and the basis weight of the sheet. The larger the basis weight of the sheet, the smaller the attenuation rate of ultrasonic waves. Therefore, the basis weight of the sheet may be determined from the attenuation rate of ultrasonic waves by obtaining the relationship between the basis weight of the sheet and the attenuation rate of ultrasonic waves through experiments or the like.

[0049] The pressure sensor 65 has a pressing part and a load cell. The pressure sensor 65 is arranged at a position downstream of the optical sensor 61 at a position between the lower end part 30 of the main conveyance path 41 and the timing roller 45. The pressing part of the pressure sensor 65 is positioned so as to be movable in the direction toward the main conveyance path 41, the direction indicated by the arrow in FIG. 3. The load cell detects the pressure applied to the pressing part. When the pressing part is pressed against the paper part on the free end side of the paper in a state where the paper is gripped by the timing roller 45, the paper generates deflection. The pressure sensor 65 detects the detection value of the load cell that receives the pressing force from the paper that tries to restore while the paper is deflecting. The hardness of the paper can be detected by the pressure sensor 65.

[0050] An inversion path 43 branching from the main conveyance path 41 is provided. One end of the inversion path 43 is connected to the paper discharge roller 15, and the other end is connected between the lower end part 30 of the main conveyance path 41 and the optical sensor 61. An inversion roller 44 is arranged on the inversion path 43.

[0051] The paper accommodated in any one of the paper feed trays 151, 152, and 153 is conveyed along the main conveyance path 41, and an image is transferred onto its surface by the transfer roller 47 and conveyed to the paper discharge roller 15. When an image is formed on the back surface of the paper, the paper discharge roller 15 reverses the rotation direction while gripping the paper without conveying the paper to the post-processing device 155. As a result, the conveyance direction of the paper is reversed, and the paper enters the inversion path 43. The paper that has entered the inversion path 43 is conveyed by the inversion roller 44 and enters the main conveyance path 41. Then, the paper is conveyed along the main conveyance path 41, and an image is transferred onto its back surface by the transfer roller 47. Then, the paper with the image transferred onto its back surface passes through the fixing roller 49 and is discharged to the paper discharge tray 159 by the paper discharge roller 15.

[0052] FIG. 4 is a diagram showing an example of the functions of the CPU of the MFP in the present embodiment. The functions shown in FIG. 4 are functions realized by the CPU 111 provided in the MFP 100 by executing a medium type detection program stored in the ROM 113, the HDD 115, or the CD-ROM 118A. Referring to FIG. 4, the CPU 111 includes a detection control unit 71, an operation reception unit 73, a print job reception unit 75, an image formation control unit 77, a conveyance control unit 79, an association unit 81, a notification unit 83, an error detection unit 85, and a history information generation unit 87.

[0053] The operation reception unit 73 controls the operation panel 160 and receives the operations input by the user to the operation unit 163. The operation reception unit 73 outputs the received operations to the detection control unit 71 and the print job reception unit 75.

[0054] The print job reception unit 75 receives a print job. In response to receiving the print job, the print job reception unit 75 outputs the print job to the image formation control unit 77 and the conveyance control unit 79. When the user instructs the execution of a print job on the operation panel 160, the operation reception unit 73 receives the print job. The print job received from the operation panel 160 includes print conditions and data to be subjected to image formation. The data to be subjected to image formation is data specified by the user. The data specified by the user includes image data output by the original document reading unit 130 reading the original document, data stored in the HDD 115, and data stored in an external computer. Also, when the communication I / F unit 112 receives a print job from an external computer, the print job reception unit 75 receives the print job received by the communication I / F unit 112. The print job received from an external computer is described in, for example, PJL (Printer Job Language) or PCL (Printer Control Language) and includes print conditions and data to be subjected to image formation.

[0055] The print job reception unit 75 executes a print job and generates print data used by the image forming unit 140 to form an image. When executing a print job, the print job reception unit 75 generates the print data based on the data to be the object of image formation according to the print conditions included in the print job. The print data is, for example, data in bitmap format. The print data corresponds to the size of the paper to be the object of image formation and defines the image to be formed on the paper with a plurality of pixel values. The print data includes four data corresponding to each of yellow, magenta, cyan, and black. Therefore, when the print data consists of a plurality of pages, it includes four data corresponding to each of yellow, magenta, cyan, and black for each of the plurality of pages.

[0056] The image formation control unit 77 controls the image forming unit 140 to form an image of print data according to the print conditions included in the print job. The image formation control unit 77 controls the image forming unit 140 so that the transfer roller 47 is charged to a potential suitable for transferring the toner image formed on the intermediate transfer belt 57 to the conveyance object to be the target of image formation, based on the print data and the basis weight. Further, the image formation control unit 77 determines image formation conditions based on the basis weight, and forms an image according to the image formation conditions. For example, when the basis weight of the conveyance object is large, the charge amount of the transfer roller 47 is set higher, and the temperature of the fixing roller 49 is set higher. On the other hand, when the basis weight of the conveyance object is small, the charge amount of the transfer roller 47 is set lower, and the temperature of the fixing roller 49 is set lower. Further, the image formation conditions may include the conveyance speed of the conveyance object required for transferring and fixing the toner image onto the paper. For example, when the basis weight of the conveyance object detected by the ultrasonic sensor 63 is large, the conveyance speed of the conveyance object is set slower, and when the basis weight of the conveyance object detected by the ultrasonic sensor 63 is small, the conveyance speed of the conveyance object is set faster. Note that the conveyance speed of the conveyance object can be adjusted by controlling the rotation speeds of the pickup rollers 151p, 152p, 153p, the paper feed rollers 151r, 152r, 153r, the timing roller 45, the transfer roller 47, the fixing roller 49, and the paper discharge roller 15 in the paper feed unit 150.

[0057] The conveyance control unit 79 controls the paper feeding unit 150 and conveys the paper accommodated in any one of the three paper feed trays 151, 152, and 153 as the conveyance object. The conveyance control unit 79 selects, as the target tray, the paper feed tray defined by default from among the three paper feed trays 151, 152, and 153, or the paper feed tray designated by the user. The conveyance control unit 79 controls the pickup rollers 151p, 152p, 153p and the paper feed rollers 151r, 152r, 153r for supplying the paper from the target tray among the three paper feed trays 151, 152, and 153 to the image forming unit 140. For example, when the paper feed tray 151 is selected as the target tray, the conveyance control unit 79 rotates the pickup roller 151p and the paper feed roller 151r. Also, when the paper feed tray 152 is selected as the target tray, the conveyance control unit 79 rotates the pickup roller 152p and the paper feed roller 152r. By this control, the conveyance object is conveyed from any one of the paper feed trays 151, 152, and 153 to the main conveyance path 41.

[0058] The detection control unit 71 controls the optical sensor 61, the ultrasonic sensor 63, and the pressure sensor 65 to obtain information regarding the physical properties of the object to be conveyed. The information regarding the physical properties includes basis weight, thickness, whiteness, presence or absence of surface coating, hardness, and information indicating whether it is an envelope or not. The basis weight is determined from the attenuation rate of ultrasonic waves and / or the transmittance of light. The whiteness and the presence or absence of surface coating are determined from the reflectance of light. The hardness is determined by the output value of the pressure sensor 65. Whether it is an envelope or not is determined based on the attenuation rate of ultrasonic waves. If the attenuation rate of ultrasonic waves is equal to or less than the threshold value, it is determined as an envelope, and if it is greater than the threshold value, it is determined as paper. The detection control unit 71 determines the type of paper based on the information regarding the physical properties of the object to be conveyed. For example, the relationship between the attenuation rate of ultrasonic waves and the basis weight is obtained in advance by experiment or simulation and is held, and based on this relationship, the basis weight is determined from the attenuation rate of ultrasonic waves. Also, the relationship between the transmittance of light and the basis weight is obtained in advance by experiment or simulation and is held, and based on this relationship, the basis weight is determined from the transmittance of light. Further, by referring to a table defining the relationship between the type of paper and the basis weight, the type of paper is determined from the determined basis weight. The types of paper include paper and envelopes. Also, the paper includes plain paper, high-quality paper, recycled paper, or photographic paper. The detection control unit 71 outputs the detected type of paper to the association unit 81 in response to detecting the type of paper.

[0059] The association unit 81 associates the type of paper input from the detection control unit 71 with the target tray and stores it in the RAM 114. The association unit 81 erases the type of paper associated with the target tray from the RAM 114 before the paper is taken out as the first object to be conveyed from the target tray. The first object to be conveyed is the paper first conveyed from the target tray by the paper feeding unit 150.

[0060] Specifically, the first conveyance object is the sheet that is first conveyed after the state of the target tray changes from the open state to the closed state. The association unit 81 detects that any one of the paper feed trays 151, 152, and 153 changes its state from the open state to the closed state. Each of the paper feed trays 151, 152, and 153 allows the pickup roller to take out the sheet in the closed state. Each of the paper feed trays 151, 152, and 153 changes its state from the closed state to the open state in which the sheet can be supplied by being pulled forward by the user. After each of the paper feed trays 151, 152, and 153 changes its state from the closed state to the open state, if it changes its state from the open state to the closed state, the sheet accommodated therein may be changed to another type of sheet. For this reason, the association unit 81 deletes the type of sheet stored in association with that paper feed tray. Thereby, even when the sheet accommodated in the target tray among the paper feed trays 151, 152, and 153 is changed to another type of sheet, the type of the sheet before the change can be prevented from being associated with the target tray.

[0061] The first conveyance object is the sheet that is first conveyed from the target tray after the MFP 100 returns from the power saving mode. The MFP 100 switches its operation mode between the normal mode and the power saving mode in which the power consumption is less than that in the normal mode. In the case of the power saving mode, the sensor for detecting the opening and closing of the paper feed trays 151, 152, and 153 does not operate in order to suppress the power consumption. For this reason, in the state of the power saving mode, the sheet accommodated in the paper feed trays 151, 152, and 153 may be replaced with another type of sheet by the user. The association unit 81 deletes the type of sheet stored in association with the target tray among the paper feed trays 151, 152, and 153 after the return from the power saving mode. Thereby, when the MFP 100 returns from the power saving mode, the type of a sheet different from the currently accommodated sheet cannot be associated with the paper feed trays 151, 152, and 153.

[0062] The association unit 81 may erase the associated type for the paper feed tray among the paper feed trays 151, 152, and 153 for which the specified time has elapsed since the type was associated. Further, the association unit 81 may erase the associated type for the paper feed trays 151, 152, and 153 when the environment has changed by a specified amount since the type was associated with the paper feed trays 151, 152, and 153. The specified change in the environment includes, for example, the case where the outside air temperature and / or humidity changes to a specified value including the case of changing.

[0063] The detection control unit 71 includes a non-printing period detection unit 91 and an image formation state detection unit 93. The image formation state detection unit 93 acquires the image formation state from the image formation control unit 77. The image formation state detection unit 93 outputs the image formation state to the non-printing period detection unit 91. The image formation state includes an in-execution state indicating that a print job is being executed, and an interrupted state in which image formation is interrupted during the execution of a print job. The interrupted state includes an adjustment interrupted state in which image formation is interrupted for temperature adjustment or cleaning, and a switching interrupted state in which the paper feed tray is switched. The adjustment interrupted state is, for example, a state in which the fixing roller 49 waits until it rises to a specified temperature. The temperature of the fixing roller 49 may vary depending on the type of paper. For this reason, the image formation operation is interrupted until the fixing roller 49 reaches a temperature suitable for the type of paper. The adjustment interrupted state is a state in which an operation of cleaning the members of the image forming unit 140 is being executed. The switching interrupted state is a state in which the paper feed trays 151, 152, and 153 are switched when a setting for forming an image on a plurality of sheets of paper is made in a print job. For example, when sheets of the same type are stored in the paper feed tray 151 and the paper feed tray 152, first, image formation is performed using the paper stored in the paper feed tray 151. Then, when the paper in the paper feed tray 151 becomes empty, image formation may be performed using the paper stored in the paper feed tray 152. In this case, the state in which image formation is interrupted while switching from the paper feed tray 151 to the paper feed tray 152 is the switching interrupted state.

[0064] The non-printing period detection unit 91 receives the image forming state from the image forming state detection unit 93. The non-printing period detection unit 91 detects the non-printing period based on the image forming state. The non-printing period is a period during which image formation by the image forming unit 140 is not performed. The non-printing period detection unit 91 determines that it is a non-printing period when the image forming state is other than the executing state. The non-printing period detection unit 91 determines the interrupted state as the non-printing period.

[0065] The detection control unit 71 discriminates the type of the paper during the non-printing period. The detection control unit 71 determines, for each of the paper feed trays 151, 152, and 153, a tray to which the type of paper is not associated by the association unit 81 as the target tray. When determining the target tray, the detection control unit 71 outputs a conveyance instruction to the conveyance control unit 79. The conveyance instruction includes tray identification information for identifying the target tray. The conveyance control unit 79 controls the paper feed unit 150 to start conveying the paper accommodated in the target tray specified by the tray identification information according to the conveyance instruction. At this time, the conveyance control unit 79 controls the paper feed unit 150 so that the paper enters the reverse path 43 and stops within the reverse path 43.

[0066] For the paper held in the reverse path 43, if the type thereof is the same as the type of the paper to be the target of image formation in the next print job, the conveyance control unit 79 conveys the paper to the main conveyance path 41 as the first paper for which the next print job is executed. When the type of the paper held in the reverse path 43 is different from the type of the paper to be the target of image formation in the next print job, if the next print job is double-sided printing, the conveyance control unit 79 discharges the paper to the discharge tray provided in the post-processing device 155. In this case, the conveyance control unit 79 discharges the paper held in the reverse path 43 to a discharge tray different from the discharge tray where the paper discharged when the next print job is executed is discharged. When the type of the paper held in the reverse path 43 is different from the type of the paper to be the target of image formation in the next print job, if the next print job is not double-sided printing, the conveyance control unit 79 leaves the paper held in the reverse path 43 as it is.

[0067] Even when there is no tray whose paper type is not associated by the association unit 81 during the non-printing period, when the user inputs a detection instruction to the operation panel 160, the detection control unit 71 determines the paper feed tray specified by the detection instruction as the target tray. In this case, the detection control unit 71 outputs a conveyance instruction to the conveyance control unit 79 to detect the paper type of the paper accommodated in the target tray.

[0068] While the paper conveyed by the paper feed unit 150 is being conveyed along the main conveyance path 41, the detection control unit 71 acquires information regarding the physical properties of the paper and detects the paper type. The detection control unit 71 outputs the detected paper type to the association unit 81. During the non-printing period, the image formation control unit 77 does not perform image formation even if the paper feed unit 150 conveys the paper.

[0069] The error detection unit 85 detects an error that occurs during image formation by the image forming unit 140. The error includes, for example, a jam error in which the paper gets stuck in the conveyance path. It may also be information input by the user operating the operation panel 160. The information input by the user is, for example, information indicating that the image quality formed on the paper has deteriorated. When an error occurs, the error detection unit 85 outputs error information indicating the content of the error to the history information generation unit 87. Also, when a sensor for reading the paper on which the image has been formed is provided, the deterioration of the image quality may be determined by inspecting the image read by the sensor.

[0070] When error information is input from the error detection unit 85, the history information generation unit 87 generates history information associating the error information with the paper type. The history information generation unit 87 identifies the paper feed tray that accommodated the paper in which the error occurred from among the paper feed tray 151, the paper feed tray 152, and the paper feed tray 153. Then, the history information generation unit 87 acquires the paper type associated by the association unit 81 with the identified paper feed tray.

[0071] The notification unit 83 notifies the user in response to the detection of the paper type by the detection control unit 71. The notification unit 83 displays, on the display unit 161, the tray identification information for identifying the paper feed tray in which the paper whose type has been detected by the detection control unit 71 is accommodated, and the type of the paper. Further, when there is error information associated by the history information generation unit 87 with the type of the paper whose type has been detected by the detection control unit 71, the notification unit 83 further displays the error information on the display unit 161.

[0072] Furthermore, with respect to the paper held in the reverse path 43 by the conveyance control unit 79, there is a case where it is discharged to the paper discharge tray by the post-processing device 155 without being image-formed. The notification unit 83 displays, on the display unit 161, the tray identification information for identifying the paper feed tray in which the paper discharged to the paper discharge tray was accommodated. Thereby, the user can perform the operation of accommodating the blank paper discharged to the paper discharge tray of the post-processing device 155 in the paper feed tray identified by the tray identification information.

[0073] FIG. 5 is a flowchart showing an example of the flow of the non-printing period detection process. The non-printing period detection process is a process executed by the CPU 111 provided in the MFP 100 by executing a medium type detection program. Referring to FIG. 5, the CPU 111 provided in the MFP 100 sets OFF in the image formation flag (step S01), and advances the process to step S02. The image formation flag is a flag indicating the image formation state, which is set to ON during image formation and set to OFF when no image is being formed. In step S02, it is determined whether a print job has been received. It waits in a standby state until a print job is received (NO in step S02), and if a print job is received (YES in step S02), the process advances to step S03.

[0074] In step S03, a paper feed tray is determined, and the process proceeds to step S04. If a paper feed tray is specified by a print job, the specified paper feed tray is determined. A paper feed tray associated with the paper type defined by the print job is determined. In step S04, an image formation flag is set to ON, and the process proceeds to step S05.

[0075] In step S05, it is determined whether it is in the standby operation. The standby operation includes an operation of raising the fixing roller 49 to a predetermined temperature and an operation of cleaning the members of the image forming unit 140. If it is in the standby operation, the process proceeds to step S06; otherwise, the process proceeds to step S08. In step S06, the image formation flag is set to OFF, and the process proceeds to step S07. In step S07, it is determined whether the standby operation has ended. It waits in a standby state until the standby operation ends (NO in step S07), and if the standby operation has ended (YES in step S07), the process proceeds to step S15.

[0076] In step S08, it is determined whether to switch the paper feed tray. When the print job defines a process of switching the paper feed trays 151, 152, and 153 and forming images on a plurality of sheets of paper, it is determined whether it is the switching timing of the paper feed tray. If it is the switching timing of the paper feed tray, the process proceeds to step S09; otherwise, the process proceeds to step S11. In step S09, the image formation flag is set to OFF, and the process proceeds to step S10. In step S10, it is determined whether the switching of the paper feed tray has ended. It waits in a standby state until the switching of the paper feed tray ends (NO in step S10), and if the switching of the paper feed tray has ended (YES in step S10), the process proceeds to step S15.

[0077] In step S11, it is determined whether an error has occurred. If an error is detected, the process proceeds to step S12; otherwise, the process proceeds to step S15.

[0078] In step S12, history information is generated, and the process proceeds to step S13. The history information includes the type of paper and error information indicating the content of the error. The type of paper is the type associated with the paper feed tray determined in step S03. In step S13, it is determined whether recovery from the error has occurred. The process waits until recovery from the error (NO in step S13), and if recovery from the error has occurred (YES in step S13), the process proceeds to step S14.

[0079] In step S14, the image formation flag is set to ON, and the process proceeds to step S15. In step S15, it is determined whether the print job has ended. If the print job has ended, the process proceeds to step S16, otherwise the process returns to step S05. In step S16, the image formation flag is set to OFF and the process ends.

[0080] FIG. 6 is a flowchart showing an example of the flow of the media type detection process. The media type detection process is a process executed by the CPU 111 provided in the MFP 100 by the CPU 111 executing a media type detection program. Referring to FIG. 6, the CPU 111 provided in the MFP 100 determines whether the image formation flag is set to OFF. If the image formation flag is not OFF, the process waits (NO in step S21), and if the image formation flag is OFF (YES in step S21), the process proceeds to step S22.

[0081] In step S22, it is determined whether there is a paper feed tray whose type has not been detected. If the type is not associated with at least one of the paper feed tray 151, the paper feed tray 152, and the paper feed tray 153, the process proceeds to step S24; otherwise, the process proceeds to step S23. Whether the type has not been detected is determined based on the detection flags corresponding to the paper feed tray 151, the paper feed tray 152, and the paper feed tray 153 respectively. The detection flag is set to ON when the type has not been detected and set to OFF when the type has been detected. Therefore, if at least one of the detection flags of the paper feed tray 151, the paper feed tray 152, and the paper feed tray 153 is ON, the process proceeds to step S24.

[0082] In step S23, it is determined whether a detection instruction has been received. A detection instruction input by the user operating the operation panel 160 is received. The detection instruction includes information specifying the paper feed tray to be detected. If a detection instruction has been received, the process proceeds to step S24; otherwise, the process returns to step S21.

[0083] In step S24, the CPU 111 causes the paper feed unit 150 to convey the paper from the paper feed tray. When the process proceeds from step S22, the CPU 111 conveys the paper accommodated in the undetected paper feed tray specified in step S22. When the process proceeds from step S23, the CPU 111 conveys the paper accommodated in the paper feed tray specified by the detection instruction input by the user.

[0084] In step S25, the physical property value of the conveyed paper is acquired. The optical sensor 61, the ultrasonic sensor 63, and the pressure sensor 65 are controlled, and the physical property value is acquired from the output values of the respective sensors. In the next step S26, the type is determined from the physical property value, and the process proceeds to step S27. In step S27, the type is associated with the paper feed tray, and the process proceeds to step S28. The type determined in step S26 is associated with the paper feed tray specified as the processing target in step S22 or step S23.

[0085] In step S28, the detection flag is set to OFF, and the process proceeds to step S29. In step S29, it is determined whether there is error information. Among the history information stored in the HDD 115, the error information associated with the type determined in step S26 is extracted. If error information is extracted from the history information, the process proceeds to step S30; otherwise, the process proceeds to step S31.

[0086] In step S30, the type and the error information are notified, and the process ends. The type and the error information are displayed on the display unit 161. In step S31, the type is notified, and the process ends. The type is displayed on the display unit 161.

[0087] FIG. 7 is a flowchart showing an example of the flow of the conveyance control process. The conveyance control process is a process executed by the CPU 111 provided in the MFP 100 by the CPU 111 executing a medium type detection program. Referring to FIG. 7, the CPU 111 provided in the MFP 100 determines whether a paper conveyance instruction has been detected. The conveyance instruction is output by the CPU 111 in step S24 of the medium type detection process. If a conveyance instruction is detected, the process proceeds to step S42; otherwise, the process proceeds to step S45.

[0088] In step S42, the paper feed tray is specified, and the process proceeds to step S43. The paper feed tray is specified by the conveyance instruction. Then, in step S43, the paper stored in the paper feed tray is conveyed along the conveyance path. While the paper is being conveyed, the physical property value of the paper is detected. In step S44, the paper is held in the standby path, and the process proceeds to step S45.

[0089] In step S45, it is determined whether an image formation instruction has been detected. If an image formation instruction has been detected, the process proceeds to step S46; otherwise, the process proceeds to step S51. In step S46, the paper feed tray containing the paper to be subjected to image formation is identified, and the process proceeds to step S47. In step S47, it is determined whether there is paper held in the reversing path 43. If there is paper held in the reversing path 43, the process proceeds to step S48; otherwise, the process proceeds to step S50.

[0090] In step S48, it is determined whether the types are the same. The type associated with the paper feed tray identified in step S46 is compared with the type of the paper held in the reversing path 43. If the types are the same, the process proceeds to step S49; otherwise, the process proceeds to step S52. In step S49, the paper held in the reversing path is conveyed, and the process proceeds to step S50. An image is formed on the paper held in the reversing path. In step S50, the paper contained in the paper feed tray identified in step S46 is conveyed, and the process proceeds to step S51. An image is formed on the paper contained in the paper feed tray.

[0091] In step S52, the paper held in the reversing path 43 is discharged to the second paper discharge tray, and the process proceeds to step S53. The second paper discharge tray is a paper discharge tray different from the paper discharge tray where the paper on which an image is to be formed is to be discharged. This makes it possible to prevent papers of different types from being mixed. In step S53, the paper feed tray where the paper discharged to the second paper discharge tray is to be stored is notified. The tray identification information of the paper feed tray associated with the same type as the type of the paper discharged to the second paper discharge tray is displayed on the display unit 161. Note that when the image formation instruction received in step S45 is not double-sided printing, the paper held in the reversing path 43 remains held in the reversing path 43.

[0092] In step S51, it is determined whether the power of the MFP 100 has been detected as being turned off. If the power-off is detected, the process ends; otherwise, the process returns to step S41.

[0093] FIG. 8 is a flowchart showing an example of the flow of the paper feed tray state setting process. The paper feed tray state setting process is a process executed by the CPU 111 provided in the MFP 100 by the CPU 111 executing a medium type detection program. Referring to FIG. 8, the CPU 111 provided in the MFP 100 determines whether the paper is detected as being empty (step S61). If the paper is detected as being empty (YES in step S61), the process proceeds to step S66; otherwise, the process proceeds to step S62.

[0094] In step S62, it is determined whether the opening and closing of the paper feed tray have been detected. If the opening and closing of the paper feed tray are detected (YES in step S62), the process proceeds to step S65; otherwise, the process proceeds to step S63.

[0095] In step S63, it is determined whether the environment has changed. When the temperature and / or humidity have changed by a predetermined value or more since the type was last detected, it is determined that the environment has changed. If no change in the environment is detected (YES in step S63), the process proceeds to step S65; otherwise, the process proceeds to step S64.

[0096] In step S64, it is determined whether a predetermined time has elapsed. If a predetermined time has elapsed since the type was last detected (YES in step S64), the process proceeds to step S65; otherwise, the process proceeds to step S66.

[0097] In step S65, the detection flag is set to ON, and the process proceeds to step S66. In step S66, it is determined whether the power of the MFP 100 has been detected as being turned off. If the power-off is detected, the process ends; otherwise, the process returns to step S61.

[0098] <First Modification Example> A non-printing period table for determining a non-printing period may be predefined. The table is stored in the HDD 115. FIG. 9 is a diagram showing an example of the non-printing period table. Referring to FIG. 9, the non-printing period table determines a non-printing period for the state of the apparatus. For example, the state of the apparatus includes a warm-up state and a post-warm-up state when the MFP 100 is started up. It is determined that it is not a non-printing period for the warm-up state, and it is determined that it is a non-printing period for the post-warm-up state.

[0099] The state of the apparatus includes a state of waiting for a print job, a state of performing a print job operation, and a state after receiving a print job instruction before the job of the MFP 100 is started. It is determined that it is a non-printing period for the state of waiting for a print job, and it is determined that it is not a non-printing period for the state of performing a print job operation and the state after receiving a print job instruction.

[0100] The state of the apparatus includes a state of continuous printing, a state of interruption (adjustment, data expansion), a state of interruption (sheet conveyance trouble), and a state after printing completion when performing job_print and copy. It is determined that it is not a non-printing period for the state of continuous printing. It is determined that it is a non-printing period for the state of interruption (adjustment, data expansion), it is determined that it is not a non-printing period for the state of interruption (sheet conveyance trouble), and it is determined that it is a non-printing period for the state after printing completion.

[0101] The state of the apparatus includes a state of continuous printing, a state of interruption (adjustment, data expansion), a state of interruption (sheet conveyance trouble), and a state after printing completion when performing job_FAX reception. It is determined that it is not a non-printing period for the state of continuous printing. It is determined that it is a non-printing period for the state of interruption (adjustment, data expansion), it is determined that it is not a non-printing period for the state of interruption (sheet conveyance trouble), and it is determined that it is a non-printing period for the state after printing completion.

[0102] When the device is in the state of executing "Job_Others", there are states during scanning / FAX reading execution, after scanning / FAX reading completion, during FAX transmission, and after FAX transmission completion. Executing "Job_Others" means executing jobs other than print jobs and copy jobs, here it means executing scan jobs and FAX transmission / reception jobs without image formation. For the states during scanning / FAX reading execution, after scanning / FAX reading completion, during FAX transmission, and after FAX transmission completion, it is defined that they are non-printing periods.

[0103] When the device is in the state of executing "Out-of-Job_Print", there are states during continuous printing, during interruption (adjustment, data expansion), during interruption (sheet conveyance trouble), and after printing completion. It is defined that the state during continuous printing is not a non-printing period. Executing "Out-of-Job_Print" means executing a printing process separately from a job. It is defined that the state during interruption (adjustment, data expansion) is a non-printing period, the state during interruption (sheet conveyance trouble) is not a non-printing period, and the state after printing completion is a non-printing period.

[0104] When the device is in the state of other operations, there is a state during test pattern reading. For the state during test pattern reading, a non-printing period is defined.

[0105] In the first modification example, for the non-printing period detection unit 91 of the detection control unit 71 included in the CPU 111 of the MFP 100, referring to the non-printing period table stored in the HDD 115, based on the state of the MFP 100 input from the image formation control unit 77, it determines whether it is a non-printing period.

[0106] <Second Modification Example> The detection flags associated with the paper feed trays 151, 152, and 153 may be erased due to the elapsed time since the type was associated and changes in the environment.

[0107] FIG. 10 is a diagram showing an example of a determination table. The determination table determines whether to detect the type for each combination of the elapsed time since the type was associated with the paper feed tray and environmental changes. Referring to FIG. 10, the determination table is a matrix in which the elapsed time after determination is shown in the vertical column and the environmental difference at the time of the previous determination is shown in the horizontal column. The elapsed time after determination indicates the elapsed time since the type was associated with the paper feed tray. The environmental difference at the time of the previous determination indicates the magnitude of the environmental change since the type was associated with the paper feed tray. When the elapsed time is short and the environmental change is small, it is determined not to detect the type. When the elapsed time is short and the environmental change is large, when the elapsed time is long and the environmental change is small, and when the elapsed time is long and the environmental change is large, it is determined to detect the type.

[0108] In the MFP 100 in the second modification, the association unit 81 included in the CPU 111 refers to the determination table stored in the HDD 115 and determines whether to erase the type associated with each of the paper feed trays 151, 152, and 153.

[0109] As described above, the MFP 100 in the present embodiment detects, for each of the paper feed trays 151, 152, and 153, a physical property value indicating the physical properties of the paper accommodated therein during a non-printing period when the image forming unit 140 is not performing image formation. Then, the MFP 100 associates the type of the paper corresponding to the physical property value. Therefore, before an image is formed on the paper accommodated in any of the paper feed trays 151, 152, and 153, the type can be associated with that paper feed tray. Therefore, since it is not necessary to detect the type of the paper after the paper feed tray to be used for image formation is determined, the time from when the paper is transported to when the image is formed can be shortened.

[0110] Further, while transporting the paper, the MFP 100 detects the physical property values of the paper and does not form an image on the paper that is the target of the detection of the physical property values. Therefore, the physical properties of the paper can be detected using the same conveyance path as the paper that is the target of image formation.

[0111] Also, when the paper that is the target of the detection of the physical property values is discharged to the discharge tray of the post-processing device 155, the MFP 100 causes the display unit 161 to display tray identification information for identifying the paper feed tray in which the paper discharged to the discharge tray was accommodated. Therefore, since the user is informed of which of the paper feed trays 151, 152, and 153 the paper discharged to the discharge tray is to be accommodated in, convenience is improved.

[0112] Also, the MFP 100 holds the paper whose physical property values have been detected in the reverse path 43, and when a print job using the same type as the held paper is executed, the paper held in the reverse path 43 is conveyed first for image formation. Therefore, an image can be formed on the paper whose physical property values have been detected.

[0113] The MFP 100 generates history information associating error information regarding an error that occurs during image formation on the paper with the type of the paper. When the physical property values of the paper accommodated in any of the paper feed trays 151, 152, and 153 are detected, the MFP 100 notifies the error information associated with the type corresponding to the detected physical property values and the history information. Therefore, since the error that occurred in the past is notified in the image formation using the paper accommodated in the paper feed tray, the user can be alerted.

[0114] The MFP 100 detects the physical property values of the paper in response to an operation input by the user during a non-printing period. Therefore, since the type of the paper accommodated in the paper feed tray is associated while the user is operating the MFP 100, the convenience of the operation is improved.

[0115] The non-printing period includes a period during which a job is executed to cause the original document reading unit 130 to read an original document and not to cause the image forming unit 140 to form an image. Examples of jobs that cause the original document reading unit 130 to read an original document and not to cause the image forming unit 140 to form an image are, for example, a scan job without image formation or a FAX transmission job. Therefore, the period during which a scan job or a FAX transmission job is executed can be effectively utilized.

[0116] The non-printing period includes a period during which a job is executed to transmit and receive data and not to cause the image forming unit 140 to form an image. For example, jobs that transmit and receive data and do not cause the image forming unit 140 to form an image are a FAX reception job without image formation and a job that transmits and receives data stored in the HDD 115. Therefore, the period during which a FAX reception job is executed can be effectively utilized.

[0117] While a printing job for continuously forming images on a plurality of sheets of paper stored in the first paper feed tray is being executed, the MFP 100 detects the physical property values of the paper stored in the second paper feed tray during an interruption period in which no image is formed on the paper. This interruption period includes a period for switching the paper feed tray, a period for adjusting the image forming unit, and a period for data expansion. Therefore, the period during which the printing job is interrupted can be effectively utilized.

[0118] When the MFP 100 detects the type of paper during an interruption period while a printing job is being executed, the MFP 100 ejects the paper whose type has been detected to a paper ejection tray different from the paper ejection tray for ejecting the paper on which an image has been formed while the printing job is being executed. Since the paper on which an image has been formed while the printing job is being executed and the paper whose type has been detected are separated, it is possible to prevent the two types of paper from being mixed.

[0119] (Item 12) The image forming apparatus according to Item 11, further comprising tray notification means for notifying tray identification information for identifying the second paper feed tray in which the ejected recording medium was accommodated in response to the recording medium being ejected to the second paper ejection tray by the paper ejection means.

[0120] In accordance with this aspect, in response to the recording medium being discharged onto the second paper discharge tray, tray identification information for identifying the second paper feed tray in which the discharged recording medium was accommodated is notified. Therefore, it is possible to notify the user of the paper feed tray in which the recording medium discharged onto the second paper discharge tray should be accommodated. Accordingly, the convenience for the user is improved.

[0121] <Summary of the Embodiment> (Item 1) A plurality of paper feed trays for accommodating recording media, detection means for detecting a physical property value indicating the physical properties of the recording medium, association means for associating the type of the recording medium corresponding to the detected physical property value with the paper feed tray in which the recording medium that was the object of detection by the detection means among the plurality of paper feed trays was accommodated, image forming means for forming an image on the recording medium using parameters for the type of the recording medium, and comprising, The detection means is an image forming apparatus that detects the physical property value of the recording medium accommodated in the paper feed tray whose type has not been associated by the association means during a non-printing period in which an image has not been formed on the recording medium by the image forming means.

[0122] In accordance with this aspect, a physical property value indicating the physical properties of the recording medium is detected, the type of the recording medium corresponding to the detected physical property value is associated with the paper feed tray in which the recording medium was accommodated, and an image is formed on the recording medium using parameters for the type of the recording medium. The physical property value of the recording medium accommodated in the paper feed tray whose type has not been associated during a non-printing period in which an image has not been formed on the recording medium is detected. Therefore, the type can be associated with the paper feed tray before an image is formed on the recording medium accommodated in the paper feed tray. Accordingly, the type is determined before the paper feed tray that is the object of image formation is determined, and once the type is determined, the parameters are determined, so there is no need to detect the physical property value after the paper feed tray is determined. As a result, the time from when the recording medium is conveyed until an image is formed can be shortened.

[0123] (Item 2) The image forming apparatus further includes a conveying unit configured to convey the recording medium accommodated in any one of the plurality of paper feed trays to the image forming unit. The detection unit detects a physical property value of the recording medium being conveyed by the conveying unit. The image forming unit does not form an image on the recording medium that is the object of detection of the physical property value by the detection unit, according to the image forming apparatus of Item 1.

[0124] According to this aspect, the recording medium accommodated in any one of the plurality of paper feed trays is conveyed to the image forming unit, the physical property value of the conveyed recording medium is detected, and an image is not formed on the recording medium that is the object of detection of the physical property value. For this reason, it is possible to detect the physical property of the recording medium conveyed using the same conveyance path as the recording medium that is the object of image formation.

[0125] (Item 3) The image forming apparatus further includes a paper discharge unit configured to discharge the recording medium that has passed through the image forming unit to a paper discharge tray. The image forming apparatus according to Item 2 further includes a tray notification unit configured to notify tray identification information for identifying the paper feed tray in which the recording medium that has been discharged to the paper discharge tray and has been the object of detection of the physical property value by the detection unit was accommodated, in response to the recording medium being discharged to the paper discharge tray by the paper discharge unit.

[0126] According to this aspect, when the recording medium that has been the object of detection of the physical property value is discharged to the paper discharge tray, tray identification information for identifying the paper feed tray in which the recording medium discharged to the paper discharge tray was accommodated is notified. For this reason, since it is notified in which of the plurality of paper feed trays the recording medium discharged to the paper discharge tray is accommodated, convenience is improved.

[0127] (Item 4) The conveying unit has a standby path for making the recording medium whose physical property value has been detected by the detection unit standby. When a print job using the type of the recording medium that has been made to wait in the standby path is executed after waiting in the standby path, the recording medium that has been made to wait in the standby path is conveyed to the image forming means prior to the recording medium accommodated in the paper feed tray corresponding to the type among the plurality of paper feed trays, in the image forming apparatus according to item 2.

[0128] According to this aspect, when a print job using the type of a recording medium whose physical property value has been detected is executed after making the recording medium wait in the standby path, the recording medium that has been made to wait in the standby path is image-formed prior to the recording medium accommodated in the paper feed tray corresponding to the type. For this reason, an image can be formed on the recording medium whose physical property value has been detected.

[0129] (Item 5) History information generation means for generating history information associating error information regarding an error occurring while the image forming unit forms an image on the recording medium with the type of the recording medium; Notification means for notifying the type corresponding to the physical property value of the detected recording medium and the error information associated with the history information in response to the physical property value of the recording medium accommodated in any one of the plurality of paper feed trays being detected by the detection means, in the image forming apparatus according to item 1.

[0130] According to this aspect, in response to the physical property value of a recording medium being detected, error information associated with the type corresponding to the detected physical property value of the recording medium is notified. For this reason, in image formation using the recording medium of that type, an error that occurred in the past is notified. Therefore, the user can be alerted.

[0131] (Item 6) Further comprising reception means for receiving an operation input by a user, The detection means detects the physical property value of the recording medium in response to a predetermined instruction being received by the reception means during the non-printing period, in the image forming apparatus according to item 1.

[0132] According to this aspect, in response to a predetermined instruction being input by a user during a non-printing period, the physical property value of the recording medium is detected. For this reason, the type of the recording medium accommodated in the paper feed tray is associated while the user is operating the image forming apparatus. Accordingly, the convenience of operation is improved.

[0133] (Item 7) The image forming apparatus according to item 1, further comprising original reading means for reading an original. The non-printing period includes a period during which a job is executed that causes the original reading means to read an original and does not cause the image forming means to form an image.

[0134] According to this aspect, the physical property value of the recording medium is detected while a job of reading an original and not forming an image is being executed. For this reason, the period during which a job of reading an original and not forming an image is being executed can be effectively utilized.

[0135] (Item 8) The image forming apparatus according to item 1, further comprising data transmission / reception means for transmitting and receiving data. The non-printing period includes a period during which a job is executed that causes the data transmission / reception means to transmit and receive data and does not cause the image forming means to form an image.

[0136] According to this aspect, the physical property value of the recording medium is detected while a job of transmitting and receiving data and not forming an image is being executed. For this reason, the period during which a job of transmitting and receiving data and not forming an image is being executed can be effectively utilized.

[0137] (Item 9) The plurality of paper feed trays include a first paper feed tray and a second paper feed tray. The non-printing period includes an interruption period during which a printing job for continuously forming images on a plurality of recording media accommodated in the first paper feed tray by the image forming means is being executed and the image forming means does not form an image on the recording media. The image forming apparatus according to claim 1, wherein the detection means detects a physical property value of the recording medium stored in the second paper feed tray during the interruption period.

[0138] According to this aspect, during an interruption period in which no image is formed on the recording medium while a printing job in which images are continuously formed on a plurality of recording media stored in the first paper feed tray is being executed, the physical property value of the recording medium stored in the second paper feed tray is detected. Therefore, the period during which the printing job is interrupted can be effectively utilized.

[0139] (Item 10) The plurality of paper feed trays further include a third paper feed tray, The image forming apparatus according to claim 9, wherein the interruption period includes a period of switching from the first paper feed tray to the third paper feed tray when the printing job targets the recording medium stored in the third paper feed tray after targeting the recording medium stored in the first paper feed tray.

[0140] According to this aspect, when the printing job targets the recording medium stored in the third paper feed tray after targeting the recording medium stored in the first paper feed tray, the physical property value of the recording medium stored in the second paper feed tray is detected during the interruption period of switching from the first paper feed tray to the third paper feed tray. Therefore, the period during which the printing job is interrupted can be effectively utilized.

[0141] (Item 11) It further includes a paper discharge means having a first paper discharge tray and a second paper discharge tray, and discharging the recording medium that has passed through the image forming means to either the first paper discharge tray or the second paper discharge tray. When the paper discharge means executes a printing job for continuously forming images on a plurality of recording media stored in the first paper feed tray by the image forming means, the recording media on which the images are formed is discharged to the first paper discharge tray among the plurality of paper discharge trays. When the physical property value of the recording media stored in the second paper feed tray is detected during the interruption period while the printing job is being executed, the recording media that is the target of the detection of the physical property value by the detection means is discharged to a second paper discharge tray different from the first paper discharge tray among the plurality of paper discharge trays. The image forming apparatus according to item 9 or 10.

[0142] According to this aspect, when a printing job for continuously forming images on a plurality of recording media stored in the first paper feed tray is being executed, the recording media on which the images are formed is discharged to the first paper discharge tray. When the physical property value of the recording media stored in the second paper feed tray is detected during the interruption period while the printing job is being executed, the recording media that is the target of the detection of the physical property value is discharged to the second paper discharge tray. For this reason, the recording media on which the images are formed when the printing job is executed and the recording media that is the target of the detection of the physical property value are separated. Therefore, it is possible to prevent two types of recording media from being mixed.

[0143] (Item 12) The image forming apparatus according to item 11, further comprising tray notification means for notifying tray identification information for identifying the second paper feed tray in which the discharged recording media was stored in response to the recording media being discharged to the second paper discharge tray by the paper discharge means.

[0144] According to this aspect, in response to the recording media being discharged to the second paper discharge tray, tray identification information for identifying the second paper feed tray in which the discharged recording media was stored is notified. Therefore, it is possible to notify the user of the paper feed tray in which the recording media discharged to the second paper discharge tray should be stored. Therefore, the convenience for the user is improved.

[0145] (Item 13) A method for detecting the type of medium executed by an image forming apparatus, The image forming apparatus includes a plurality of paper feed trays for storing recording media, an image forming means for forming an image on the recording medium a detecting step of detecting a physical property value indicating a physical property of the recording medium an associating step of associating the type of the recording medium corresponding to the detected physical property value with the paper feed tray in which the recording medium that was the object of detection by the detecting means among the plurality of paper feed trays was accommodated an image forming control step of causing the image forming means to form an image using a parameter for the type of the recording medium, the method comprising: The detecting step includes a step of detecting a physical property value of the recording medium accommodated in the paper feed tray in which the type has not been associated in the associating step during a non-printing period in which no image is formed on the recording medium by the image forming means. A method for detecting the type of medium

[0146] According to this aspect, it is possible to provide a method for detecting the type of medium that can shorten the time from transporting the recording medium to forming an image.

[0147] (Item 14) A medium type detection program executed by a computer that controls an image forming apparatus, The image forming apparatus includes a plurality of paper feed trays for accommodating a recording medium, an image forming means for forming an image on the recording medium, a detecting step of detecting a physical property value indicating a physical property of the recording medium, an associating step of associating the type of the recording medium corresponding to the detected physical property value with the paper feed tray in which the recording medium that was the object of detection by the detecting means among the plurality of paper feed trays was accommodated, and an image forming control step of causing the computer to cause the image forming means to form an image using a parameter for the type of the recording medium. The detection step includes a step of detecting physical property values of the recording medium accommodated in the paper feed tray not associated with a type in the association step during a non-printing period in which an image is not formed on the recording medium by the image forming means, and is a medium type detection program.

[0148] According to this aspect, it is possible to provide a medium type detection program capable of shortening the time from transporting the recording medium to forming an image.

[0149] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Signs

[0150] 100 MFP, 110 Main circuit, 111 CPU, 112 Communication I / F section, 113 ROM, 114 RAM, 115 HDD, 116 Facsimile section, 118 External storage device, 118A CD-ROM, 120 Automatic document feeder, 125 Document tray, 127 Document discharge tray, 130 Document reading section, 140 Image forming section, 150 Paper feeding section, 151, 152, 153 Paper feed tray, 155 Post-processing device, 159 Discharge tray, 160 Operation panel, 161 Display section, 163 Operation section, 165 Touch panel, 167 Hard key section, 15 Discharge roller, 30 Lower end, 41 Main conveyance path, 43 Reverse path, 44 Reverse roller, 45 Timing roller, 47 Transfer roller, 49 Fixing roller, 51C, 51M, 51Y, 51K Image forming unit, 53Y Transfer roller, 57 Intermediate transfer belt, 61 Optical sensor, 63 Ultrasonic sensor, 65 Pressure sensor, 71 Detection control section, 73 Operation reception section, 75 Print job reception section, 77 Image forming control section, 79 Conveyance control section, 81 Association section, 83 Notification section, 85 Error detection section, 87 History information generation section, 91 Non-printing period detection section, 93 Image forming state detection section.

Claims

1. A plurality of paper feed trays for accommodating a recording medium; Detection means for detecting a physical property value indicating the physical properties of the recording medium; Association means for associating the type of the recording medium corresponding to the detected physical property value with the paper feed tray in which the recording medium that was the object of detection by the detection means among the plurality of paper feed trays was accommodated; Image forming means for forming an image on the recording medium using parameters for the type of the recording medium, comprising: The detection means detects the physical property value of the recording medium accommodated in the paper feed tray whose type is not associated by the association means during a non-printing period in which no image is formed on the recording medium by the image forming means. An image forming apparatus.

2. Further comprising conveying means for conveying the recording medium accommodated in any one of the plurality of paper feed trays to the image forming means, The detection means detects the physical property value of the recording medium being conveyed by the conveying means, The image forming means does not form an image on the recording medium that is the object of detection of the physical property value by the detection means. The image forming apparatus according to claim 1.

3. The conveying means discharges the recording medium that has passed through the image forming means to a discharge tray, When the recording medium that is the object of detection of the physical property value by the detection means is discharged to the discharge tray by the conveying means, further comprising tray notification means for notifying tray identification information for identifying the paper feed tray in which the recording medium discharged to the discharge tray among the plurality of paper feed trays was accommodated. The image forming apparatus according to claim 2.

4. The conveying means has a standby path for waiting the recording medium, When a print job using the type of the recording medium that has been made to wait in the standby path is executed after the recording medium whose physical property value has been detected by the detection means is made to wait in the standby path, the recording medium made to wait in the standby path is conveyed to the image forming means prior to the recording medium accommodated in the paper feed tray corresponding to the type among the plurality of paper feed trays. The image forming apparatus according to claim 2.

5. History information generation means for generating history information associating error information regarding an error occurring during the image forming unit forming an image on the recording medium with the type of the recording medium, A notification means for notifying error information associated with the type corresponding to the physical property value of the detected recording medium and the history information in response to the physical property value of the recording medium accommodated in any one of the plurality of paper feed trays being detected by the detection means; The image forming apparatus according to claim 1, further comprising:

6. Further comprising a reception means for receiving an operation input by a user, The detection means detects a physical property value of the recording medium in response to a predetermined instruction being received by the reception means during the non-printing period. The image forming apparatus according to claim 1.

7. Further comprising an original reading means for reading an original, The non-printing period includes a period during which a job for causing the original reading means to read an original and not causing the image forming means to form an image is being executed. The image forming apparatus according to claim 1.

8. Further comprising a data transmission / reception means for transmitting and receiving data, The non-printing period includes a period during which a job for causing the data transmission / reception means to transmit and receive data and not causing the image forming means to form an image is being executed. The image forming apparatus according to claim 1.

9. The plurality of paper feed trays include a first paper feed tray and a second paper feed tray, The non-printing period includes an interruption period during which a printing job for continuously forming images on a plurality of recording media accommodated in the first paper feed tray by the image forming means is being executed and the image forming means does not form an image on the recording media. The detection means detects a physical property value of the recording medium accommodated in the second paper feed tray during the interruption period. The image forming apparatus according to claim 1.

10. The plurality of paper feed trays further include a third paper feed tray, The interruption period includes a period of switching from the first paper feed tray to the third paper feed tray when the printing job targets the recording medium accommodated in the third paper feed tray after targeting the recording medium accommodated in the first paper feed tray for image formation. The image forming apparatus according to claim 9.

11. Having a first paper discharge tray and a second paper discharge tray, and further comprising a paper discharge means for discharging the recording medium that has passed through the image forming means to either the first paper discharge tray or the second paper discharge tray, When a printing job is being executed in which the paper discharging means continuously forms images on a plurality of recording media accommodated in the first paper feeding tray by the image forming means, the recording media on which the images have been formed are discharged to the first paper discharging tray among the plurality of paper discharging trays. When the physical property value of the recording media accommodated in the second paper feeding tray is detected during the interruption period while the printing job is being executed, the recording media that is the target of the detection of the physical property value by the detection means is discharged to a second paper discharging tray different from the first paper discharging tray among the plurality of paper discharging trays. The image forming apparatus according to claim 9 or 10.

12. A tray notification means for notifying tray identification information for identifying the second paper feeding tray in which the discharged recording media was accommodated in response to the recording media being discharged to the second paper discharging tray by the paper discharging means. The image forming apparatus according to claim 11, further comprising:

13. A method for detecting the type of medium executed in an image forming apparatus, The image forming apparatus includes a plurality of paper feeding trays for accommodating recording media, And an image forming means for forming an image on the recording media. A detection step of detecting a physical property value indicating the physical properties of the recording media, An association step of associating the type of the recording media corresponding to the detected physical property value with the paper feeding tray in which the recording media that is the target of the detection by the detection means among the plurality of paper feeding trays is accommodated, And an image forming control step of causing the image forming means to form an image using parameters for the type of the recording media. The method for detecting the type of medium includes: The detection step includes a step of detecting the physical property value of the recording media accommodated in the paper feeding tray in which the type has not been associated in the association step during a non-printing period in which no image is being formed on the recording media by the image forming means.

14. A medium type detection program executed by a computer for controlling an image forming apparatus, The image forming apparatus includes a plurality of paper feeding trays for accommodating recording media, And an image forming means for forming an image on the recording media. A detection step of detecting a physical property value indicating the physical properties of the recording media, An association step of associating the type of the recording media corresponding to the detected physical property value with the paper feeding tray in which the recording media that is the target of the detection by the detection means among the plurality of paper feeding trays is accommodated, An image formation control step of causing the image forming means to form an image using parameters for the type of the recording medium, and causing the computer to execute the step. The detection step includes a step of detecting a physical property value of the recording medium accommodated in the paper feed tray in which the type is not associated in the association step during a non-printing period in which an image is not formed on the recording medium by the image forming means, and is a medium type detection program.

Images