JP2019127376A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that enables appropriate image formation according to a type of a recording medium and improves productivity.SOLUTION: An MFP 100 includes: a plurality of sub-transport paths SP1, SP2, SP3; a main transport path 41 connected to the plurality of sub transport paths SP1, SP2, SP3; a detection device 59 having a detection area DA in the main transport path 41 and for detecting information relating to a sheet as paper information while the sheet as a recording medium is moving in a detection area DA; and a guidance device 300 for guiding the sheet so that the sheet moves through a predetermined target position TP in the detection area DA even if the sheet enters the main transport path 41 from any of the plurality of sub transport paths SP1, SP2, SP3.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of setting an image forming condition based on information on a recording medium.

  In an image forming apparatus such as MFP (Multi Function Peripheral), a plurality of types of paper may be used. In this case, the quality of the formed image can be improved by appropriately setting the image forming conditions such as the toner transfer voltage and the fixing temperature during image formation according to the type of paper.

  JP 2008-94600 A (PTL 1) proposes a sheet conveying apparatus for automatically detecting the thickness of a sheet on which an image is to be formed. Specifically, in the sheet conveying apparatus, the sheet is conveyed between two sheet guide plates disposed to face each other in the vertical direction. After the entry of the conveyed sheet into the predetermined position is confirmed, the lever body presses the sheet against the upper sheet guide plate. In this state, the rotation of the roller for conveying the sheet is stopped, and the sheet to be stopped is irradiated with light. At this time, the thickness of the sheet is detected based on the light transmitted through the sheet. Thereafter, the pressing of the sheet by the lever body is released and the rotation of the roller is resumed, and the sheet is conveyed.

According to the above configuration, the sheet is positioned in a state of being temporarily stopped at a predetermined position (light irradiation position) in the sheet conveyance path. However, temporarily stopping the sheet during conveyance to the image forming unit causes a problem that the time required for image formation is prolonged and productivity is lowered.
JP 2008-94600A

  The present invention has been made to solve the above-described problems, and one of the objects of the present invention is to enable an appropriate image formation according to the type of the recording medium and to improve the productivity. It is providing a forming apparatus.

  The present invention has been made to solve the above-described problems, and according to one aspect of the present invention, an image forming apparatus includes a plurality of secondary conveyance paths and a main conveyance path connected to the plurality of secondary conveyance paths. And detection means having a detection area in the main conveyance path and detecting information on the recording medium as medium information while the recording medium is moving the detection area, and the recording medium being main conveyance from any of a plurality of secondary conveyance paths And a guiding unit for guiding the recording medium so that the recording medium moves a predetermined target position in the detection area even when entering a path.

  According to this aspect, even if the recording medium enters the main transport path from any of the plurality of sub transport paths, the recording medium is guided to the target position in the detection area by the guiding means. Thereby, since the recording medium moves at a predetermined target position, it is not necessary to stop the movement of the recording medium in order to arrange the recording medium at the target position in the detection area. Therefore, it is possible to detect the medium information with high accuracy while reducing the time required to detect the medium information. As a result, it is possible to provide an image forming apparatus capable of forming an appropriate image according to the type of recording medium based on the medium information, and having improved productivity.

  Preferably, the guiding means has a contact guiding surface that contacts at least a part of one side of the recording medium entering the main conveyance path from any of the plurality of secondary conveyance paths.

  According to this aspect, at least a part of one surface of the recording medium entering the main transport path comes into contact with the contact guide surface, so that the posture of the recording medium when moving in the main transport path can be easily achieved. It can be adjusted. Therefore, by adjusting the attitude of the recording medium when passing the target position to the target attitude, it is possible to easily detect the medium information with higher accuracy.

  Preferably, the detection area is set at a position separated by more than 0 mm and not more than 10 mm from the downstream end of the contact guide surface in the recording medium conveyance direction.

  According to this aspect, the recording medium guided by the contact guide surface is guided to the target position with high accuracy. This improves the detection accuracy of the medium information.

  Preferably, the plurality of sub transport paths include first and second sub transport paths, the contact guide surface includes a first guide surface and a second guide surface facing each other, and the guide means includes the first When a recording medium that is positioned between the second sub-transport path and the second sub-transport path and is moved along the first sub-transport path is sent to the main transport path, one surface of the recording medium is the first guide surface. Is provided such that one surface of the recording medium comes into contact with the second guide surface when the recording medium moved in the second sub-conveying path is sent to the main conveying path.

  According to this aspect, a plurality of recording media entering the main transport path from the first sub transport path and the second sub transport path can be guided to the target position in the detection area in a target posture with a simple configuration. .

  Preferably, the image forming apparatus further includes a route selection unit that selects any of the plurality of sub-transport routes, and the guide unit is configured to be able to shift to a predetermined guide state with respect to the selected sub-transport route. Be done.

  According to this aspect, the state of the guiding means is switched according to the selected sub-transfer route. As a result, there is no need to separately provide a configuration for guiding the recording medium to the target position for each of the secondary conveyance paths. Therefore, while suppressing the increase in a number of parts, compactization of a guidance means is realized.

  Preferably, the image forming apparatus further includes a path selection unit that selects any one of the plurality of sub-transport paths, and a size selection unit that selects the size of the recording medium, and the guide unit includes the selected sub-transport path and the selected sub-transport path. It is configured to be able to shift to a guidance state predetermined for the combination of the selected recording medium sizes.

  According to this aspect, the state of the guiding means is switched according to the combination of the selected sub-transport path and the selected recording medium size. This makes it possible to guide the recording medium to the target position more appropriately. In addition, there is no need to separately provide a configuration for guiding the recording medium to the target position for each of the secondary conveyance path and the size of the recording medium. Therefore, while suppressing the increase in a number of parts, compactization of a guidance means is realized.

  Preferably, the plurality of sub-transport paths include first and second sub-transport paths, and the guide means is elastically deformable having a first guide surface and a second guide surface facing each other as contact guide surfaces. A first member that is disposed at a position facing the first guide surface of the guide member and the guide member, and that restricts elastic deformation of the guide member in a direction in which the second guide surface is directed to a predetermined first range. A second member that is arranged at a position facing the second guide surface of the restricting member and the guide member and restricts elastic deformation of the guide member in the direction in which the first guide surface is directed to a predetermined second range. The guide member is positioned between the first sub-transport path and the second sub-transport path, and the recording medium that has moved along the first sub-transport path is sent to the main transport path. The recording medium contacts the first guide surface and moves along the second sub-transport path. The recording medium is provided so as to contact with the second guide surface when the recording medium is fed to the main conveying path.

  According to this aspect, when the recording medium that has moved along the first sub-conveying path comes into contact with the first guide surface of the guide member, the guide member is elastically deformed in the direction in which the second guide surface is directed. At this time, the recording medium is guided to the target position by the elastic deformation of the guide member being restricted to the first range by the first restriction member. On the other hand, when the recording medium that has moved along the second sub-transport path comes into contact with the second guide surface of the guide member, the guide member is elastically deformed in the direction in which the first guide surface faces. At this time, the recording medium is guided to the target position by the elastic deformation of the guide member being restricted by the second restricting member by the second range. Thereby, the structure of the drive device for switching the state of the guide means becomes unnecessary. Therefore, with a simple configuration, it is possible to guide the recording medium from the first and second auxiliary conveyance paths to the target position. As a result, cost reduction of the image forming apparatus is realized.

  According to another aspect of the present invention, the image forming apparatus has a transport path and a detection area in the transport path, and moves information of the recording medium while moving the detection area of the recording medium transported through the transport path. Detection means for detecting as medium information, guiding means for guiding the recording medium moving along the conveyance path so that the recording medium moving along the conveyance path moves a predetermined target position in the detection area, Size of the recording medium The guide means includes a guide member configured to be capable of transitioning to a predetermined guide state for the selected recording medium size.

  According to this aspect, by selecting the size of the recording medium that moves along the transport path, the guide member can be shifted to the guiding state corresponding to the size of the selected recording medium. In this case, the recording medium moving on the transport path is appropriately guided by the guide member to the target position of the detection area according to the selected size. Thus, there is no need to stop the movement of the recording medium in order to position the recording medium at the target position in the detection area. Therefore, it is possible to detect the medium information with high accuracy while reducing the time required to detect the medium information. As a result, it is possible to provide an image forming apparatus capable of forming an appropriate image according to the type of recording medium based on the medium information, and having improved productivity.

  Preferably, the recording medium is a sheet, the medium information includes information indicating a basis weight of the sheet, and the detection unit receives the light from the detection area and the light projecting unit that emits light to the detection area. It includes a light receiving unit that outputs a signal according to the amount of light received, and an acquisition unit that acquires a basis weight of a sheet based on an output signal of the light receiving unit.

  According to this aspect, the basis weight of the paper is acquired with high accuracy. Thereby, appropriate image formation can be performed based on the acquired basis weight.

FIG. 2 is a perspective view showing an appearance of the MFP in the first embodiment. FIG. 2 is a block diagram showing an outline of a hardware configuration of an MFP. FIG. 4 is a schematic side view showing the internal configuration of part of the image forming unit and the paper feeding unit. FIG. 6 is a diagram showing an example of functions of the CPU of the MFP in the first embodiment. It is a side view which shows the structure of the guide apparatus in 1st Embodiment, and its peripheral member. It is the front view which looked at the guidance apparatus of FIG. 5 along the direction of arrow K. FIG. FIG. 7 is a side view showing the state of the guiding device in the first embodiment when a sheet is introduced into the main conveyance path from the upper sheet feed tray through the sub conveyance path. FIG. 7 is a side view showing the state of the guiding device in the first embodiment when a sheet is introduced from the manual feed tray to the main conveyance path through the sub conveyance path. FIG. 14 is a side view showing the state of the guiding device in the first embodiment when a sheet is introduced from the middle and lower sheet feed trays to the main conveyance path through the sub conveyance path. FIG. 14 is a diagram illustrating an example of functions of the CPU of the MFP according to the second embodiment. FIG. 16 is a diagram showing an example of functions of the CPU of the MFP in the third embodiment. It is a side view which shows the structure of the guide apparatus in 3rd Embodiment, and its peripheral member. FIG. 14 is a side view showing the state of the guiding device in the second embodiment when a sheet enters the main conveyance path from the upper sheet feed tray through the sub conveyance path. FIG. 14 is a side view showing the state of the guiding device in the second embodiment when a sheet enters the main conveyance path from the manual feed tray through the sub conveyance path. FIG. 10 is a side view illustrating a state of the guide device according to the second embodiment when a sheet enters the main transport path from the middle and lower sheet feed trays through the sub transport path. FIG. 16 is a diagram illustrating an example of functions of the CPU of the MFP in the fourth embodiment. It is a side view which shows the structure of the guide apparatus in 4th Embodiment, and its peripheral member.

  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 description about them will not be repeated. In the following description, an MFP will be described as an example of the image forming apparatus. Further, in the MFP described below, it is assumed that a sheet such as plain paper, high quality paper, recycled paper, or photographic paper is used as a recording medium to form an image.

First Embodiment
FIG. 1 is a perspective view showing the appearance of the MFP in the first embodiment. FIG. 2 is a block diagram showing an outline of the hardware configuration of the MFP. Referring to FIGS. 1 and 2, MFP 100 is an example of an image forming apparatus, and is an example of an image forming apparatus, and an automatic document for conveying a document to document reading unit 130 and document reading unit 130 for reading a document. A conveying device 120, an image forming unit 140 for forming an image on a sheet based on image data, a sheet feeding unit 150 for supplying the sheet to the image forming unit 140, and an operation panel 160 as a user interface Including.

  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 an image formed on the document by the document reading unit 130 The read document is discharged onto the document discharge tray 127. The automatic document feeder 120 includes a document detection sensor for detecting a document placed on the document tray 125.

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

  The document reading unit 130 includes a light source that emits 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, light emitted from the light source is reflected by the document, and the reflected light forms an image by the photoelectric conversion element. When the photoelectric conversion element receives the light reflected by the original, it generates image data in which the received light is converted into an electric signal. The document reading unit 130 outputs the image data to the CPU 111 provided in the main circuit 110.

  The sheet feeding unit 150 conveys sheets stored in first to third sheet feeding trays and a manual feed tray described later to the image forming unit 140. The sheet feeding unit 150 detects information on a sheet conveyed to the image forming unit 140 as sheet information. In the present embodiment, the sheet information is the basis weight of the sheet. Details of the configuration and operation for detecting sheet information in the sheet feeding unit 150 will be described later.

  The image forming unit 140 is controlled by the CPU 111 and forms an image by a known electrophotographic method. In the present embodiment, the image forming unit 140 is conveyed by the paper feeding unit 150 based on image data input from the CPU 111 and a command signal from the CPU 111 based on paper information detected by the paper feeding unit 150. Form an image on a sheet of paper. The sheet on which the image is formed is discharged to the discharge tray 159. The image data output from the CPU 111 to the image forming unit 140 includes image data such as print data received from the outside as well as the image data input from the document reading unit 130.

  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 are included. CPU 111 is connected to automatic document feeder 120, document reading unit 130, image forming unit 140, sheet feeding unit 150, and operation panel 160, and controls the entire MFP 100.

  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 image data continuously sent from the document reading unit 130.

  Operation panel 160 is provided on the top of MFP 100. 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 a user, information about acquired image data, and the like. Note that, in place of the LCD, for example, an organic EL (electroluminescence) display can be used as long as it is a device that displays an image.

  The operation unit 163 includes a touch panel 165 and a hard key unit 167. The touch panel 165 is a capacitive type. The touch panel 165 is not limited to the electrostatic capacitance type, but may be another type such as a resistive film type, a surface acoustic wave type, an infrared type, or an electromagnetic induction type.

  The touch panel 165 is provided such that the detection surface thereof is superimposed on the display unit 161 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 and the size of the display surface of the display unit 161 are the same. 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 at which the user instructs 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 from the touch panel 165 can be replaced with the coordinates of the display surface.

  Hard key portion 167 includes a plurality of hard keys. The hard key is, for example, a contact switch. The touch panel 165 detects a position designated by the user on the display surface of the display unit 161. When the user operates 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 since the posture is often upright. This is to allow the user to easily view the display surface of the display unit 161 and to easily instruct the operation unit 163 with a finger.

  Communication I / F unit 112 is an interface for connecting MFP 100 to the 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). 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. 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.

  The facsimile unit 116 is connected to a public switched telephone network (PSTN), 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, converts the received facsimile data into print data printable by the image forming unit 140, and outputs the print data to the image forming unit 140. As a result, the image forming unit 140 forms an image of facsimile data received by the facsimile unit 116 on a sheet. In addition, the facsimile unit 116 converts the data stored in the HDD 115 into facsimile data, and transmits the data to a facsimile apparatus connected to the PSTN.

  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 mounted. 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 controls the external storage device 118 to read a program to be executed by the CPU 111 from the CD-ROM 118A. The read program may be stored in the RAM 114 and executed.

  The recording medium for storing the program to be executed by the CPU 111 is not limited to the CD-ROM 118A, and a flexible disc, a cassette tape, an optical disc (Magnetic Optical Disc) / MD (Mini Disc) / DVD (Digital Versatile Disc) ), IC card, optical card, mask ROM, semiconductor memory such as EPROM (Erasable Programmable ROM), etc. may be used. Furthermore, the CPU 111 downloads a program from a computer connected to the network and stores the program in the HDD 115, or a computer connected to the network writes the program to the HDD 115 and loads the program stored in the HDD 115 to the RAM 114 Then, the program may be executed by the CPU 111. The program here includes not only a program directly executable by the CPU 111 but also a source program, a compressed program, an encrypted program, and the like.

  FIG. 3 is a schematic side view showing an internal configuration of a part of the image forming unit and the sheet feeding unit. Referring to FIG. 3, a main conveyance path 41 indicated by a thick dotted line is basically formed to extend in the vertical direction inside MFP 100. The main conveyance path 41 is a path for guiding the sheet conveyed from the sheet feeding unit 150 to the sheet discharge tray 159 through the image forming unit 140. In the main transport path 41 of this example, the lower end 30 on the opposite side of the upper end 13 located above the image forming unit 140 constitutes a carry-in entrance for receiving paper from the paper supply unit 150. Further, the upper end portion 13 of the main conveyance path 41 constitutes a discharge port for discharging the sheet on which the image is formed onto the sheet discharge tray 159. A 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, and SP3 of a paper feeding unit 150 described later.

  The paper feed unit 150 includes three paper feed trays 151, 152, 153 and a manual feed tray 154. The three paper feed trays 151, 152, and 153 are stacked and arranged in this order from top to bottom. The manual feed tray 154 is provided on the side wall 101 of the MFP 100 and is located below the image forming unit 140. As indicated by a thick dashed-dotted line in FIG. 3, in the sheet feeding unit 150, the sheet feeding tray 151 located at the upper stage of the three sheet feeding trays 151, 152, 153 extends from the sheet feeding tray 151 to the lower end portion 30 of the main conveyance path 41. The secondary conveyance path SP1 is formed on the lower side. Further, a sub conveyance path SP2 is formed so as to extend from the manual feed tray 154 to the lower end portion 30 of the main conveyance path 41. Further, two conveyance paths 152a and 153a are formed extending from the paper feed trays 152 and 153 positioned at the middle and lower stages of the three paper feed trays 151, 152 and 153 to the lower end portion 30 of the main conveyance path 41, respectively. . A portion having a predetermined length from the lower end 30 of the main transport path 41 of each of the two transport paths 152a and 153a is a sub transport path SP3 shared by the two transport paths 152a and 153a.

  A sheet feeding roller 151 r for feeding the sheet stored in the sheet feeding tray 151 to the main conveyance path 41 is provided in the sub conveyance path SP1. The sub conveyance path SP2 is provided with a paper feed roller 154r for supplying the sheet stored in the manual feed tray 154 to the main conveyance path 41. The transport path 152a is provided with a paper feed roller 152r for supplying the paper stored in the paper feed tray 152 to the main transport path 41 through the sub transport path SP3. Further, a paper feed roller 153r for supplying the paper stored in the paper feed tray 153 to the main transport path 41 through the sub transport path SP3 is provided in the transport path 153a.

  In MFP 100, when forming an image on a sheet, a tray in which sheets to be subjected to image formation are stored is selected from among three sheet feeding trays 151, 152, 153 and manual feed tray 154 as a target tray. The sheet feed roller corresponding to the tray selected as the target tray among the three sheet feed trays 151, 152, 153 and the manual feed tray 154 operates to move from the tray selected as the target tray to the secondary conveyance paths SP1, SP2, A sheet on which an image is to be formed is supplied to the main transport path 41 through one of SP3.

  The image forming unit 140 includes yellow, magenta, cyan, and black image forming units 51Y, 51M, 51C, and 51K. An image is formed by driving at least one of the image forming units 51Y, 51M, 51C, and 51K. 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 to the image forming units 51Y, 51M, 51C and 51K, respectively. Since the image forming units 51Y, 51M, 51C, and 51K differ only in the color of the toner to be handled, the image forming unit 51Y for forming a yellow image will be described here.

  The image forming unit 51Y includes an exposure head to 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 print data (electrical signal). The emitted laser light is one-dimensionally scanned by a polygon mirror provided in the exposure head to expose the photosensitive drum. The direction in which the photosensitive drum is scanned one-dimensionally is the main scanning direction. The photosensitive drum is charged by a charger and then irradiated with a laser beam emitted by the exposure head. Thereby, an electrostatic latent image is formed on the photosensitive drum. Subsequently, a 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.

  On the other hand, the intermediate transfer belt 57 is suspended by the driving roller 55 and the roller 55A so as not to be slackened. When the drive roller 55 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 55A rotates counterclockwise.

  Thus, the image forming units 51Y, 51M, 51C, and 51K transfer the toner image onto the intermediate transfer belt 57 in order. The timing at which each of the image forming units 51Y, 51M, 51C, 51K transfers the 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.

  In the main transport path 41, a timing roller 45, a transfer roller 47, and a fixing roller 49 are arranged at intervals in this order from the lower end 30 to the upper end 13. The sheet supplied from the sheet feeding unit 150 to the main conveyance path 41 is sent to the timing roller 45.

  The timing roller 45 adjusts the conveyance state of the paper in the main conveyance path 41 so that the paper 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 sheet conveyed by the timing roller 45 is pressed against the intermediate transfer belt 57 by the transfer roller 47, and the transfer roller 47 is charged to form yellow, magenta, cyan, and the like formed so as to overlap on the intermediate transfer belt 57. The black toner image is transferred to the paper. 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 paper basis weight.

  The sheet on which the toner image has been transferred is conveyed to the fixing roller 49 and heated by the fixing roller 49. Thus, the toner is melted and fixed on the sheet. Thereafter, the paper after the image formation is discharged from the upper end portion 13 of the main transport path 41 onto the paper discharge tray 159 by the paper discharge roller 15. The temperature of the fixing roller 49 is controlled by the CPU 111 to be a value suitable for the basis weight of the sheet.

  MFP 100 in the present embodiment is provided with detection device 59 having a detection area in main conveyance path 41. The detection device 59 includes a light projecting unit 59a and a light receiving unit 59b, and the light projecting unit 59a and the light receiving unit 59b sandwich the main transport path 41 at a position between the lower end 30 of the main transport path 41 and the timing roller 45. They are arranged to face each other. The light projecting unit 59a includes a light emitting element such as a light emitting diode, a drive circuit for the light emitting element, and an optical system, and emits light along the optical axis. An area in the main conveyance path 41 along the optical axis of the light emitting unit 59a is a detection area. The light receiving unit 59 b includes a light receiving element such as a photodiode and outputs a signal corresponding to the amount of light received by the light receiving element. The detection area of the detection device 59 is an area between the light emitting unit 59a and the light receiving unit 59b.

  In the detection device 59, light of a predetermined light amount is emitted from the light emitting unit 59a to the detection area. In this state, by moving the sheet across the detection area, a part of the sheet being moved is irradiated with light. At this time, part of the light emitted to the sheet is transmitted through the sheet, and the rest of the light is absorbed by the sheet or reflected from the sheet. The light receiving unit 59 b receives the light transmitted through the sheet, and outputs a signal corresponding to the amount of light received to the CPU 111.

  In the CPU 111, based on the output signal of the light receiving unit 59b, information on a sheet moving in the detection area is acquired as sheet information. In the present embodiment, the sheet information is information indicating the basis weight of the sheet moving in the detection area. Based on the acquired paper information, image forming conditions for the paper are set. The image forming conditions for the paper include the voltage applied to the transfer roller 47 required to properly transfer the toner image formed on the intermediate transfer belt 57 to the paper, and the toner image transferred to the paper. The temperature of the fixing roller 49 required for proper fixing is included. For example, when the basis weight of the paper detected by the detection device 59 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 sheet detected by the detection device 59 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 forming conditions of the sheet may include the transport speed of the sheet required to transfer and fix the toner image on the sheet. For example, when the basis weight of the paper detected by the detection device 59 is large, the paper transport speed is set to be slower, and when the basis weight of the paper detected by the detection device 59 is small, the paper transport speed is set. Is set faster. Note that the sheet conveyance speed can be adjusted by controlling the rotation speeds of the sheet feeding roller, timing roller 45, transfer roller 47, fixing roller 49, and sheet discharge roller 15 of the sheet feeding unit 150.

  In order to set the image forming conditions more appropriately according to the type of paper, it is necessary to obtain the paper information with higher accuracy. However, as described above, when acquiring paper information based on the amount of light transmitted through the paper, if the position of the paper moving in the detection region changes, the output signal of the light receiving unit 59b also changes. As a result, the detection results vary and it is difficult to accurately determine the sheet information. This variation mainly occurs due to the plurality of sub-conveying paths of the sheet in the sheet feeding unit 150. Specifically, the above-described variation is caused by, for example, the position and orientation of the sheet entering the detection area from one of the three sub-transport paths SP1, SP2, and SP3 of the paper feed section 150, and the paper feed section 150. This occurs because the position and posture of the sheet entering the detection area from the other sub-transport path among the plurality of sub-transport paths SP1, SP2, SP3 are different. Here, the position of the paper entering the detection area is the distance from the light projecting unit 59a, and the posture of the paper entering the detection area is defined by the optical axis of the light emitted from the light projecting unit 59a and the paper. It is an angle. Here, a line connecting the center of the light projecting unit 59a and the center of the light receiving unit 59b is taken as the optical axis of the light emitted from the light projecting unit 59a. Therefore, in the MFP 100 of this example, even when the paper enters the main transport path 41 from any of the three sub transport paths SP1, SP2, and SP3, the paper is determined in advance in the detection area of the detection device 59. A guiding device is provided for guiding the sheet to move the target position. Details of the guiding device will be described later.

  FIG. 4 is a view showing an example of functions of the CPU of the MFP in the first embodiment. The functions shown in FIG. 4 are functions formed in CPU 111 when CPU 111 provided in MFP 100 executes an image forming program stored in ROM 113, HDD 115, or CD-ROM 118A.

  Referring to FIG. 4, CPU 111 includes a print data generation unit 61, an image formation control unit 62, a paper information acquisition unit 63, a route selection unit 64, and a guidance state switching unit 66.

  The print data generation unit 61 executes a print job and generates print data used by the image forming unit 140 to form an image. The print data generation unit 61 executes a print job, for example, when the communication I / F unit 112 receives a print job from an external computer. The print job 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. Further, when the user operates the operation unit 163, the print data generation unit 61 generates print data based on the data designated by the user. The data designated by the user includes image data that the document reading unit 130 reads and outputs a document, data stored in the HDD 115, and data stored in an external computer.

  The print data is, for example, data in a bitmap format. The print data corresponds to the size of the sheet to be subjected to image formation, and an image to be formed in the sheet is defined by a plurality of pixel values. The print data includes four data corresponding to each of yellow, magenta, cyan and black. Therefore, when the printing data is composed of a plurality of pages, the printing data includes four data corresponding to each of yellow, magenta, cyan, and black. The print data generation unit 61 outputs the print data to the image formation control unit 62.

  The path selection unit 64 selects one of the three sub-conveying paths SP1, SP2, and SP3 to which the sheet is conveyed. First, the path selection unit 64 selects a tray defined by print conditions from among the three paper feed trays 151, 152, 153 and the manual feed tray 154. When the print job is received from the outside, the print condition is determined by the print job. Also, when the user operates the operation panel 160, the print conditions are determined by the operation input by the user. Here, the tray selected by the path selection unit 64 from the plurality of paper feed trays 151, 152, 153 and the manual feed tray 154 is the target tray. The path selection unit 64 gives the image formation control unit 62 tray information indicating the target tray.

  Each of the three paper feed trays 151, 152, 153 and the manual feed tray 154 has a size of the paper to be stored and a direction of the paper to be conveyed. Therefore, when the document reading unit 130 reads a document, the path selection unit 64 detects the size of the document, and the same size as the document size among the three paper feed trays 151, 152, 153 and the manual feed tray 154. A tray for storing a sheet of paper may be selected as the target tray. When one of the three paper feed trays 151, 152, 153 and the manual feed tray 154 is determined by default, the path selection unit 64 selects the three paper feed trays 151, 152, 153 and the manual feed tray 154. The tray defined by default among the above may be selected as the target tray.

  The path selection unit 64 selects the sub-conveying path corresponding to the target tray from among the sub-conveying paths SP1, SP2, and SP3. Specifically, when the target tray is the sheet feeding tray 151, the sub-conveying path SP1 is selected, and when the target tray is the sheet feeding tray 152 or the sheet feeding tray 153, the sub-conveying path SP3 is selected, and the target tray is manually fed. In the case of the tray 154, the sub conveyance path SP2 is selected. The path selection unit 64 provides the guidance state switching unit 66 with information indicating the sub-transfer route selected from among the sub-transfer routes SP1, SP2, and SP3.

  Here, a plurality of guide devices that guide the paper to the target position are predetermined so as to correspond to a plurality (three in this example) of the sub-transport paths SP1, SP2, and SP3 connected to the main transport path 41, respectively. It is configured to be able to shift to the guidance state of. The guiding state switching unit 66 controls the guiding device to shift to the guiding state corresponding to the selected secondary conveyance path based on the information supplied from the path selecting unit 64.

  The image forming control unit 62 supplies a sheet for supplying a sheet from the target tray indicated by the tray information given from the path selecting unit 64 to the image forming unit 140 among the three sheet feeding trays 151, 152, 153 and the manual feed tray 154. Control the paper roller. For example, the image formation control unit 62 rotates the paper feed roller 151r when tray information indicating the paper feed tray 151 is given. Further, the image forming control unit 62 rotates the sheet feeding roller 152 r when tray information indicating the sheet feeding tray 152 is given. By this control, the sheet is conveyed from any one of the sheet feed trays 151, 152, 153 and the manual feed tray 154 to the main conveyance path 41.

  The paper information acquisition unit 63 receives the paper information based on the output signal of the light receiving unit 59b of the detection device 59 when the paper supplied from the paper supply unit 150 to the main transport path 41 moves in the detection area of the detection device 59. get. Further, the sheet information acquisition unit 63 supplies the acquired sheet information to the image formation control unit 62. Specifically, the basis weight of the paper as the paper information is obtained by, for example, obtaining a relationship between the basis weight of the paper and the output signal of the light receiving unit 59b in advance by experiment or simulation, and maintaining the obtained relationship. The basis weight can be easily determined from the output signal of the light receiving unit 59b based on the relationship.

  The image forming control unit 62 is configured to transfer the toner image formed on the intermediate transfer belt 57 to a potential suitable for transferring the toner image formed on the intermediate transfer belt 57 to the sheet on which the image is to be formed based on the printing data and the sheet information. The image forming unit 140 is controlled to be charged. Further, based on the sheet information, the image formation control unit 62 adjusts the temperature of the fixing roller 49 so that the toner is fixed at a temperature suitable for the sheet on which the image is to be formed. Further, the image forming control unit 62 controls the sheet feeding of the sheet feeding unit 150 corresponding to the specified tray so that the sheet is conveyed at a conveyance speed suitable for the sheet to be subjected to the image formation based on the sheet information. The operations of the roller, the timing roller 45, the transfer roller 47, the fixing roller 49, and the paper discharge roller 15 may be controlled.

  FIG. 5 is a side view showing the configuration of the guide device and its peripheral members in the first embodiment, and FIG. 6 is a front view of the guide device of FIG. In FIG. 5 and some drawings to be described later, in order to facilitate understanding of the shapes of the main transport path 41 and the plurality of sub transport paths SP1, SP2, and SP3 and their positional relationships, the sub transport paths SP1 and SP2 are mutually connected. Two different types of hatching are given, and two different types of dot patterns are given to the main transport path 41 and the sub transport path SP3. Further, in FIG. 6, a part of the sheet pa moving on the sub conveyance path SP1 of FIG. 5 is shown, and the advancing direction of the sheet pa is indicated by a white arrow.

  As indicated by a dotted line in FIG. 5, the detection device 59 is arranged to have a detection area DA in the main transport path 41. The detection area DA of the detection device 59 extends in the direction intersecting the traveling direction of the sheet pa and intersecting the sheet pa moving on the main conveyance path 41. In the detection area DA, the target position TP is set at a position separated by a predetermined distance d1 from the light emitting unit 59a along the optical axis of the light emitting unit 59a. The target position TP is an ideal position where the sheet pa moving on the main conveyance path 41 to detect the basis weight of the sheet should pass in the detection area DA.

  Referring to FIGS. 5 and 6, in the vicinity of the connecting portion between lower end portion 30 of main transport path 41 and a plurality of sub transport paths SP1 to SP3, a path forming member that partitions sub transport path SP1 and sub transport path SP3. B1 is provided. Further, a path forming member B2 is provided which divides the sub conveyance path SP3 and the sub conveyance path SP2.

  Referring to FIG. 6, the guiding device 300 includes a guiding member 310, a drive shaft 320, a motor 330 and a drive circuit 340. The drive shaft 320 is connected to the rotation shaft of the motor 330, and is provided to extend along the upper edge of the path forming member B1. The drive circuit 340 provides a pulse signal to the motor 330 based on the control of the guiding state switching unit 66 of FIG. 4. The motor 330 is, for example, a stepping motor, and rotates the drive shaft 320 in one direction or the reverse direction based on a pulse signal supplied from the drive circuit 340.

  The guide member 310 is a rectangular plate-like member, and is disposed between the sub conveyance path SP1 and the sub conveyance paths SP2 and SP3. Specifically, the guide member 310 is attached to the drive shaft 320 so as to extend from the path forming member B1 to the space in the main transport path 41. Further, the guide member 310 is fixed to the drive shaft 320 in the rotational direction of the drive shaft 320. As a result, as shown by thick arrows in FIG. 5, the guide member 310 rotates around the drive shaft 320 as the drive shaft 320 rotates as the motor 330 operates.

  The guide member 310 has a first guide surface 311 and a second guide surface 312 facing each other. The first guide surface 311 is held in a state facing the space downstream of the sub transport path SP1 so that one surface of the path forming member B1 forming the sub transport path SP1 extends into the main transport path 41. . The second guide surface 312 faces the space downstream of the sub-transport path SP3 and the sub-transport path SP2 so that one surface of the path forming member B1 that forms the sub-transport path SP3 extends into the main transport path 41. It is held in the state.

  A distance d2 from the downstream ends of the first guide surface 311 and the second guide surface 312 of the guide member 310 to the detection area DA in the traveling direction of the paper pa conveyed on the main conveyance path 41 is greater than 0 mm and 10 mm. It is set to be as follows. The distance d2 is preferably set to 5 mm or less, which is larger than 0 mm.

  The guiding device 300 according to the first embodiment is configured to be able to shift to a plurality of guiding states respectively corresponding to the plurality of secondary conveyance paths SP1, SP2, and SP3. At the time of image formation in MFP 100, guiding device 300 shifts to the guiding state corresponding to the sub-conveying path along which sheet pa is conveyed.

  FIG. 7 is a side view showing the state of the guiding device 300 in the first embodiment when the sheet pa enters the main conveyance path 41 from the upper sheet feeding tray 151 through the sub conveyance path SP1. Referring to FIG. 7, when sheet pa is conveyed to main conveyance path 41 through sub conveyance path SP1, drive shaft 320 is held at a predetermined rotation angle with respect to sub conveyance path SP1. As a result, when the guiding device 300 shifts to the guiding state corresponding to the sub conveyance path SP1, as shown by the thick solid line arrow in FIG. 7, the sheet pa entering the main conveyance path 41 from the sub conveyance path SP1 is the target. Guided to position TP.

  In this case, since the distance d2 (FIG. 5) from the downstream end of the first guide surface 311 to the detection area DA is set to be greater than 0 mm and equal to or less than 10 mm, the sheet pa of the paper pa that has passed through the guide member 310 is set. It is suppressed that the part largely fluctuates in the extending direction of the detection area DA. Therefore, the sheet pa can be guided to the target position TP with high accuracy. When the distance d2 is set to be larger than 0 mm and 5 mm or less, the sheet pa can be guided to the target position TP with high accuracy. In the guide device 300 according to the present embodiment, the paper pa entering the main transport path 41 from the sub transport path SP1 along the first guide surface 311 when in the guide state corresponding to the sub transport path SP1. It is configured to travel a fixed distance (for example, a distance of 5 mm or more). Accordingly, the posture of the paper pa from the guide member 310 toward the target position TP can be adjusted to a predetermined target posture.

  Here, the attitude of the sheet pa in the main transport path 41 is determined by the angle between the sheet pa passing the target position TP and the direction in which the detection area DA extends. The target posture is an ideal posture in which the paper pa moving on the main transport path 41 is to be maintained in the detection area DA in order to accurately detect the basis weight of the paper pa. For example, the paper pa passing through the target position TP. And the detection area DA make an angle of 90 ° or approximately 90 °.

  FIG. 8 is a side view showing the state of the guide device 300 in the first embodiment when the paper pa enters the main transport path 41 from the manual feed tray 154 through the sub transport path SP2. When the sheet pa is conveyed to the main conveyance path 41 through the sub conveyance path SP2, the drive shaft 320 is held at a predetermined rotation angle with respect to the sub conveyance path SP2. As a result, the guide device 300 shifts to the guide state corresponding to the sub-transport path SP2, so that the paper pa entering the main transport path 41 from the sub-transport path SP2 is the target as indicated by the thick dotted arrow in FIG. It is led to the position TP. In this case, the sheet pa can be guided to the target position TP with high accuracy for the same reason as when the sheet pa enters the main transport path 41 from the sub transport path SP1. In the guide device 300 according to the present embodiment, the paper pa entering the main transport path 41 from the sub transport path SP2 along the second guide surface 312 when in the guide state corresponding to the sub transport path SP2. It is configured to travel a fixed distance (for example, a distance of 5 mm or more). Accordingly, the posture of the paper pa from the guide member 310 toward the target position TP can be adjusted to a predetermined target posture.

  FIG. 9 is a side view showing the state of the guide device 300 in the first embodiment when the paper pa enters the main transport path 41 from the middle and lower sheet feed trays 152, 153 through the sub transport path SP3. When the sheet pa is conveyed to the main conveyance path 41 through the sub conveyance path SP3, the drive shaft 320 is held at a predetermined rotation angle with respect to the sub conveyance path SP3. As a result, the guide device 300 shifts to the guide state corresponding to the sub-transport path SP3, so that the paper pa entering the main transport path 41 from the sub-transport path SP3 as shown by a thick dashed line arrow in FIG. It is led to the target position TP. In this case, the sheet pa can be guided to the target position TP with high accuracy for the same reason as when the sheet pa enters the main transport path 41 from the sub transport path SP1. In the guide device 300 according to the present embodiment, the paper pa entering the main transport path 41 from the sub transport path SP3 along the second guide surface 312 when in the guide state corresponding to the sub transport path SP3. It is configured to travel a fixed distance (for example, a distance of 5 mm or more). Accordingly, the posture of the paper pa from the guide member 310 toward the target position TP can be adjusted to a predetermined target posture.

  According to the above configuration, even when the paper pa that is the object of image formation enters the main transport path 41 from any of the plurality of sub transport paths SP1 to SP3, the paper pa moves through the target position TP. . Thus, there is no need to stop the movement of the sheet pa in order to place the sheet pa at the target position TP. Therefore, it is possible to detect the sheet information with high accuracy while reducing the time required to detect the sheet information. As a result, it becomes possible to perform appropriate image formation according to the type of paper pa based on the paper information, and productivity is improved.

  Further, according to the above configuration, at least a part of one surface of the paper pa entering the main transport path 41 moves while being in contact with either the first guide surface 311 or the second guide surface 312. Thus, it is possible to easily adjust the attitude of the sheet pa when moving in the main conveyance path 41. Therefore, by adjusting the posture of the paper pa when passing through the target position TP to the target posture, it is possible to easily detect the paper pa with higher accuracy.

  Furthermore, according to the above configuration, the state of the guiding device 300 can be switched according to the selected sub conveyance path. Thus, there is no need to separately provide a configuration for guiding the sheet pa to the target position TP for each of the secondary conveyance paths. Therefore, while suppressing the increase in a number of parts, compactization of guidance device 300 is realized.

Second Embodiment
MFP 100 in the second embodiment has the same configuration and the same operation as MFP 100 in the first embodiment except that the functions formed in CPU 111 and the plurality of guidance states to which guidance device 300 can be transferred are different. Have. The differences between MFP 100 in the second embodiment and MFP 100 in the first embodiment will be described below.

  FIG. 10 is a diagram illustrating an example of functions of the CPU of the MFP according to the second embodiment. Similar to the first embodiment, the functions illustrated in FIG. 10 are functions formed in the CPU 111 when the CPU 111 included in the MFP 100 executes the image forming program stored in the ROM 113, the HDD 115, or the CD-ROM 118A. is there.

  Referring to FIG. 10, CPU 111 includes a size selection unit 65 in addition to the function of CPU 111 in the first embodiment shown in FIG. In the present embodiment, the print data generation unit 61 adds the print data to the image formation control unit 62 and the path selection unit 64 and outputs the print data to the size selection unit 65.

  The size selection unit 65 selects the size of the sheet based on the tray selected as the target tray by the path selection unit 64 from the three paper feed trays 151, 152, 153 and the manual feed tray 154, and the selected size is selected. Is given to the guidance state switching unit 66. Here, in the present embodiment, the paper size is a size in a direction (paper width direction) orthogonal to the paper traveling direction passing through each of the three sub-transport paths SP1 to SP3 and parallel to the paper. means. For example, the size of the sheet in the case of conveying the A3 size sheet with its longitudinal direction parallel to the advancing direction is the case in which the A4 size sheet is conveyed in the lateral direction parallel to the advancing direction. It is the same as the paper size.

  The guide device 300 according to the present embodiment corresponds to the combination of the sub-transport path selected by the path selection unit 64 from the three sub-transport paths SP1 to SP3 and the paper size selected by the size selection unit 65. It is configured to be able to shift to a plurality of predetermined guidance states. Based on information given from the route selection unit 64 and the size selection unit 65, the guidance state switching unit 66 shifts to a guidance state corresponding to the combination of the selected sub-transport route and the selected paper size. The guidance device 300 is controlled.

  As described above, the reason why the plurality of guiding states of the guiding device 300 are determined according to the combination of the sub-conveying path selected from among the sub-conveying paths SP1 to SP3 and the size of the selected sheet To do. The guiding device 300 presses the sheet in the thickness direction by contacting one side of the sheet conveyed from the sub conveyance paths SP1 to SP3 by the first guiding surface 311 or the second guiding surface 312 of the guiding member 310. . Accordingly, the traveling direction of the paper is changed by curving in the direction in which the paper is pressed. At this time, if the size of the sheet in the direction (width direction of the sheet) perpendicular to the sheet traveling direction and parallel to the sheet is large, the sheet rubbing in the traveling direction, that is, the bending of the sheet becomes large. On the other hand, if the size in the width direction of the paper is small and orthogonal to the paper traveling direction, the paper is reduced in the traveling direction.

  Therefore, in the guide device 300 according to the present embodiment, for each of the sub-transport paths SP1 to SP3, a larger pressing force acts on the sheet as the sheet size is larger, and a smaller pressing force is exerted on the sheet as the sheet size is smaller. In order to operate, a plurality of guiding states are set according to the size of the sheet.

  Specifically, the guiding state of the guide device 300 is such that the larger the selected paper size, the more the guide member 310 moves in the direction of paper travel in the sub transport path selected from the sub transport paths SP1 to SP3. It is set to tilt more greatly. In addition, the guidance state of the guide device 300 is set so that the smaller the size of the selected paper, the smaller the inclination with respect to the paper traveling direction in the sub transport path selected from the sub transport paths SP1 to SP3. Be done. As a result, an appropriate pressing force in accordance with the tension of the sheet from the guide member 310 acts on the sheet supplied from the sheet feeding unit 150 to the main conveyance path 41.

  When the paper traveling direction in one of the plurality of sub transport paths SP1 to SP3 and the paper traveling direction in the main transport path 41 are parallel or substantially parallel, the sub transport path There is almost no need to bend the sheet at the connection with the main transport path 41. In this case, a single guiding state common to the sizes of a plurality of types of sheets may be set for the sub-transporting path.

  According to the above configuration, the guide state of the guide device 300 is switched according to the combination of the sub-transport path selected from the sub-transport paths SP1 to SP3 and the selected paper size. This makes it possible to guide the sheet to the target position TP more appropriately. In addition, there is no need to separately provide a configuration for guiding the sheet to the target position TP for each of the secondary conveyance path and the sheet size. Therefore, while suppressing the increase in a number of parts, compactization of guidance device 300 is realized.

Third Embodiment
MFP 100 in the third embodiment has the same configuration and the same operation as MFP 100 in the first embodiment except that the functions formed in CPU 111 and the configuration of guiding device 300 are different. The differences between MFP 100 in the third embodiment and MFP 100 in the first embodiment will be described below.

  FIG. 11 is a diagram illustrating an example of functions of the CPU of the MFP according to the third embodiment. Similar to the first embodiment, the function illustrated in FIG. 11 is a function formed in CPU 111 by CPU 111 included in MFP 100 executing an authentication program stored in ROM 113, HDD 115, or CD-ROM 118A. .

  Referring to FIG. 11, CPU 111 does not have guiding state switching unit 66 among the functions of CPU 111 in the first embodiment shown in FIG.

  The image formation control unit 62 transmits the sheets from the target tray indicated by the tray information among the three paper feed trays 151, 152, 153 and the manual feed tray 154 to the image forming unit 140 based on the tray information given from the path selection unit 64. Control the paper feed roller for feeding. Thereafter, the image formation control unit 62 determines the image forming unit 140, the paper feed rollers 151 r to 154 r, the timing roller 45, the transfer roller 47, and the fixing roller 49 based on the print data and the paper information given from the paper information acquisition unit 63. And controls the operation of the discharge roller 15.

  FIG. 12 is a side view showing the configuration of the guide device and its peripheral members in the third embodiment. As indicated by a dotted line in FIG. 12, the detection device 59 is arranged to have a detection area DA in the main transport path 41 as in the first embodiment. In the detection area DA, the target position TP is set at a position separated from the light projecting unit 59a by a predetermined distance d1 along the optical axis of the light projecting unit 59a.

  Referring to FIG. 12, path forming members B1 and B2 are provided in the vicinity of the connecting portion between the lower end portion 30 of the main transport path 41 and the plurality of sub transport paths SP1 to SP3, as in the first embodiment. It is done. The guiding device 300 in the present embodiment is composed of a guiding member 350, a first restricting member 360 and a second restricting member 370.

  The guide member 350 is a rectangular thin plate member that can be elastically deformed, and is provided to extend a certain distance along the upper edge of the path forming member B1 between the sub transport path SP1 and the sub transport paths SP2 and SP3. There is. The guide member 350 is made of, for example, an elastic member having a thickness of about 0.25 mm. As an elastic member of the guide member 350, for example, a sheet-like member made of resin such as PET (polyethylene terephthalate) or a sheet-like member made of metal can be used.

  The guide member 350 has a first guide surface 351 and a second guide surface 352 facing each other. The lower half of the first guide surface 351 is fixed so that most of the lower half of the first guide surface 351 contacts one surface of the path forming member B1 that forms the sub-transport path SP1. The upper half of the first guide surface 351 faces the space downstream of the sub-transport path SP1 so that one surface of the path forming member B1 that forms the sub-transport path SP1 extends into the main transport path 41. Is held by. The second guide surface 352 faces the space downstream of the sub-transport path SP3 and the sub-transport path SP2 so that one surface of the path forming member B1 that forms the sub-transport path SP3 extends into the main transport path 41. It is held in the state.

  The distance d2 from the downstream ends of the first guide surface 351 and the second guide surface 352 of the guide member 350 to the detection area DA in the traveling direction of the paper transported along the main transport path 41 is the first embodiment. Similarly to the above, it is set so as to be 10 mm or less larger than 0 mm. The distance d2 is preferably set to 5 mm or less, which is larger than 0 mm.

  The first restricting member 360 is a rectangular thin plate-like member, and is provided at a position facing the first guide surface 351 of the guide member 350 with the sub transport path SP1 interposed therebetween and spaced apart from the first guide surface 351. ing. The first restricting member 360 extends a certain distance in parallel with the upper edge of the path forming member B1. The first restricting member 360 is disposed so as to gradually approach the first guide surface 351 of the guide member 350 as it goes from upstream to downstream in the paper traveling direction.

  In the present embodiment, the first restricting member 360 is attached to the main body (housing or the like) of the MFP 100 so that the lower half portion has a certain positional relationship with respect to the sub-transport path SP1 and the path forming member B1, for example. It is fixed. The first restricting member 360 is configured by an elastic member having a thickness of about 0.1 mm, for example. As an elastic member of the first restricting member 360, for example, a sheet-like member made of resin such as PET (polyethylene terephthalate) or a sheet-like member made of metal can be used. In this case, the upper half of the first restricting member 360 can be elastically deformed.

  The second restricting member 370 is a rectangular thin plate-like member, and faces the second guiding surface 352 of the guiding member 350 with the sub conveyance paths SP2 and SP3 interposed therebetween and at a position away from the second guiding surface 352. It is provided. The second restricting member 370 extends a certain distance in parallel with the upper edge of the path forming member B1. The second restricting member 370 is disposed so as to gradually approach the second guide surface 352 of the guide member 350 as it goes from upstream to downstream in the paper traveling direction.

  In the present embodiment, the second restricting member 370 is configured such that the lower half portion has a fixed positional relationship with respect to the sub-transport paths SP2 and SP3 and the path forming member B2, for example. Fixed to). Similar to the first restricting member 360, the second restricting member 370 is made of, for example, an elastic member having a thickness of about 0.1 mm. As the elastic member of the second regulating member 370, for example, a resin sheet-like member such as PET (polyethylene terephthalate) or a metal sheet-like member can be used. In this case, the upper half of the second restricting member 370 can be elastically deformed.

  When the guide member 350 receives a force from the first guide surface 351, the guide member 350 elastically deforms in the direction to which the second guide surface 352 is directed and bends, and contacts the second restricting member 370. In addition, when receiving a force from the second guide surface 352, the guide member 350 elastically deforms in the direction in which the first guide surface 351 is directed and bends, and contacts the first restricting member 360. For this reason, the guiding member 350 has the second guiding surface 352 by differentiating the position where the first restricting member 360 contacts the guiding member 350 and the position where the second restricting member 370 contacts the guiding member 350. The amount by which the guide member 350 elastically deforms in the direction in which the guide member 350 is elastically deformed can be different from the amount by which the guide member 350 elastically deforms in the direction in which the first guide surface 351 moves. Further, the elasticity of the first restricting member 360 and the second restricting member 370 may be different.

  The guiding device 300 according to the third embodiment is configured to be able to shift to a plurality of guiding states respectively corresponding to the plurality of secondary conveyance paths SP1, SP2, and SP3. At the time of image formation in MFP 100, guiding device 300 shifts to the guiding state corresponding to the sub-conveying path on which the sheet is conveyed among the sub-conveying paths SP1 to SP3.

  FIG. 13 is a side view showing a state of the guide device 300 in the third embodiment when a sheet enters the main transport path 41 from the upper sheet feed tray 151 through the sub transport path SP1. Referring to FIG. 13, when a sheet is transported to main transport path 41 through sub transport path SP <b> 1, the sheet that has moved along sub transport path SP <b> 1 contacts first guide surface 351 of guide member 350. As a result, the upper half of the guide member 350 is elastically deformed in the direction in which the second guide surface 352 is directed, and the second guide surface 352 comes into contact with the downstream end of the second restricting member 370. In this case, the second restricting member 370 restricts the deformation of the guide member 350 to a predetermined range while elastically deforming. In this way, when the guide device 300 shifts to the guide state corresponding to the sub-transport path SP1, the sheet entering the main transport path 41 from the sub-transport path SP1 as shown by a thick solid line arrow in FIG. It is led to the target position TP.

  In this case, since the distance d2 (FIG. 12) from the downstream end of the first guide surface 311 to the detection area DA is set to be greater than 0 mm and equal to or less than 10 mm, the sheet is placed at the target position TP with high accuracy. It can lead. When the distance d2 is set to be larger than 0 mm and 5 mm or less, the sheet pa can be guided to the target position TP with high accuracy. Further, in the guide device 300 according to the present embodiment, the sheet entering the main transport path 41 from the sub transport path SP1 along the first guide surface 351 when in the guide state corresponding to the sub transport path SP1. It is configured to travel a fixed distance (for example, a distance of 5 mm or more). Thus, the posture of the sheet from the guide member 350 toward the target position TP can be adjusted to a predetermined target posture.

  FIG. 14 is a side view showing the state of the guide device 300 in the third embodiment when a sheet enters the main transport path 41 from the manual feed tray 154 through the sub transport path SP2. When the sheet is conveyed to the main conveyance path 41 through the sub conveyance path SP <b> 2, the sheet moved through the sub conveyance path SP <b> 2 contacts the second guiding surface 352 of the guiding member 350. As a result, the upper half of the guide member 350 is elastically deformed in the direction toward the first guide surface 351, and the first guide surface 351 comes into contact with the downstream end of the first restricting member 360. In this case, the first restricting member 360 restricts the deformation of the guiding member 350 to a predetermined range while elastically deforming. In this way, when the guide device 300 shifts to the guide state corresponding to the sub-transport path SP2, the sheet entering the main transport path 41 from the sub-transport path SP2 as shown by a thick dotted line arrow in FIG. It is led to the target position TP. In this case, the sheet can be guided to the target position TP with high accuracy, for the same reason as when the sheet enters the main conveyance path 41 from the sub conveyance path SP1. Further, in the guiding device 300 according to the present embodiment, the sheet entering the main conveyance path 41 from the sub conveyance path SP2 along the second guide surface 352 when in the guiding state corresponding to the sub conveyance path SP2. It is configured to travel a fixed distance (for example, a distance of 5 mm or more). Thus, the posture of the sheet from the guide member 350 toward the target position TP can be adjusted to a predetermined target posture.

  FIG. 15 is a side view showing a state of the guide device 300 in the third embodiment when a sheet enters the main transport path 41 from the middle and lower sheet feed trays 152 and 153 through the sub transport path SP3. When the sheet is transported to the main transport path 41 through the sub transport path SP3, the sheet that has moved along the sub transport path SP2 contacts the second guide surface 352 of the guide member 350. Thereby, the upper half of the guide member 350 is elastically deformed in the direction in which the first guide surface 351 is directed.

  Here, the paper traveling direction in the sub transport path SP3 and the paper traveling direction in the main transport path 41 are substantially parallel, and the inclination angle of the sub transport path SP3 with respect to the main transport path 41 is the sub transport path with respect to the main transport path 41. It is sufficiently smaller than the inclination angle of SP2. Therefore, the degree of elastic deformation of the guide member 350 when the sheet that has moved through the sub-transport path SP3 contacts the second guide surface 352 of the guide member 350 is the degree of elastic deformation of the guide member 350. The degree of elastic deformation when contacting the second guide surface 352 is sufficiently small. Thus, in this example, the separated state between the guide member 350 and the first restricting member 360 is maintained.

  In this way, when the guide device 300 shifts to the guide state corresponding to the sub-transport path SP2, the sheet entering the main transport path 41 from the sub-transport path SP2 as shown by a thick dotted line arrow in FIG. It is led to the target position TP. In this case, the sheet can be guided to the target position TP with high accuracy, for the same reason as when the sheet enters the main conveyance path 41 from the sub conveyance path SP1. Further, in the guide device 300 according to the present embodiment, the sheet entering the main transport path 41 from the sub transport path SP3 along the second guide surface 352 when in the guide state corresponding to the sub transport path SP3. It is configured to travel a fixed distance (for example, a distance of 5 mm or more). Thus, the posture of the sheet from the guide member 350 toward the target position TP can be adjusted to a predetermined target posture.

  According to the above configuration, the configuration of the drive device for switching the guiding state of the guiding device 300 becomes unnecessary. Therefore, the sheet can be guided from the secondary conveyance paths SP1, SP2, and SP3 to the target position TP with a simple configuration. As a result, cost reduction of MFP 100 is realized.

  In the above configuration, when the sheet is supplied to the main conveyance path 41 through the sub conveyance path SP1, the elastic deformation of the guide member 350 is restricted by the second restriction member 370 capable of elastic deformation. Thereby, it is possible to suppress a large load from being applied to the portion of the sheet that contacts the first guide surface 351 when the guide member 350 guides the sheet. Further, when the sheet is supplied to the main transport path 41 through the sub transport path SP2, the elastic deformation of the guide member 350 is restricted by the first restricting member 360 that can be elastically deformed. Accordingly, it is possible to suppress a large load from being applied to the portion of the sheet that contacts the second guide surface 352 when the guide member 350 guides the sheet. As a result, the generation of paper dust due to the contact between the sheet and the guide member 350 is reduced.

  The first restricting member 360 and the second restricting member 370 may be configured by members that are not elastically deformed or hardly elastically deformed. In this case, the degree of elastic deformation of the guide member 350 can be accurately adjusted. Therefore, the design of the guiding device 300 for guiding the sheet to the target position TP is further facilitated.

Fourth Embodiment
In MFP 100 according to the fourth embodiment, only one sheet feeding tray 151 is provided in sheet feeding unit 150, and only one sub-conveying path SP1 is provided from sheet feeding tray 151 to main conveyance path 41, and in CPU 111 It has the same configuration and the same operation as MFP 100 in the second embodiment except that the formed function is different. The differences between MFP 100 of the fourth embodiment and MFP 100 of the second embodiment will be described below.

  FIG. 16 is a diagram showing an example of functions of the CPU of the MFP in the fourth embodiment. The function shown in FIG. 16 is a function formed in CPU 111 by CPU 111 included in MFP 100 executing an image forming program stored in ROM 113, HDD 115 or CD-ROM 118A, as in the second embodiment. is there.

  Referring to FIG. 16, the function of CPU 111 is different from the function of CPU 111 in the second embodiment shown in FIG. 10 in that it does not have path selector 64, size selector 65 is a size selector It is the point changed to 65A. The other functions are the same as the functions shown in FIG. 10, and therefore the description will not be repeated here. Also in the present embodiment, the print data generation unit 61 outputs the print data to the image formation control unit 62. The size selection unit 65A selects the target tray from the plurality of sheet feeding trays 151, 152, 153 and the manual feed tray 154, and selects the size of the sheets stored in the target tray. The size selection unit 65A provides the guidance state switching unit 66 with information indicating the size of the selected sheet. The size selection unit 65A selects a tray defined by the print conditions as a target tray. When the print job is received from the outside, the print condition is determined by the print job. Also, when the user operates the operation panel 160, the print conditions are determined by the operation input by the user. In addition, when the document reading unit 130 reads a document, the size selection unit 65A detects the size of the document, and of the three paper feed trays 151, 152, 153 and the manual feed tray 154, the size is the same as the document size. Select a tray for storing paper as the target tray. In addition, when one of the three paper feed trays 151, 152, 153 and the manual feed tray 154 is determined by default, the size selection unit 65A selects the three paper feed trays 151, 152. , 153 and the manual feed tray 154, the tray defined by default is selected as the target tray.

  The size selection unit 65A selects the sheet size based on the tray selected as the target tray among the three sheet feeding trays 151, 152, 153 and the manual feed tray 154, and guides the information indicating the selected size. It gives to the switching unit 66.

  Also in the present embodiment, as in the second embodiment, the size of the sheet is a sheet in a direction (width direction of the sheet) orthogonal to the advancing direction of the sheet passing through the sub conveyance path SP1 and parallel to the sheet Means the size of.

  Here, the guiding device 300 in the present embodiment is configured to be able to shift to a plurality of guiding states predetermined according to the size of the sheet selected by the size selecting unit 65A. The guide state switching unit 66 controls the guide device 300 to shift to the guide state corresponding to the size of the selected paper based on the information given from the size selection unit 65A. In addition, the guidance state switching unit 66 provides the image forming control unit 62 with information indicating which of the plurality of guidance states the guidance device 300 is in. In this case, the image formation control unit 62 operates in the same manner as in the second embodiment based on information given from the guidance state switching unit 66.

  FIG. 17 is a side view showing the configuration of the guide device and its peripheral members in the fourth embodiment. Referring to FIG. 17, in the present embodiment, only one sheet feeding tray 151 is provided in sheet feeding unit 150, whereby one sub-conveying path is provided between sheet feeding tray 151 and main conveyance path 41. Only SP1 is formed. Even in such a case, according to the above configuration, the guiding state of the guiding device 300 can be switched according to the size of the selected sheet. As a result, it is possible to more appropriately guide the sheet to the target position TP in the detection area DA of the detection device 59. Further, it is not necessary to provide a configuration for guiding the paper to the target position TP for each paper size. Therefore, while suppressing the increase in a number of parts, compactization of guidance device 300 is realized.

<Modification>
In the above embodiment, an example of using a sheet as a recording medium has been described, but the present invention is not limited to this. As a recording medium on which an image is to be formed, a sheet-like member made of resin such as an OHP film may be used in addition to paper.

  In the second embodiment, the guiding state is determined in advance for each of the plurality of sub transport paths SP1 to SP3 for each sheet size, but the color or the material of the sheet is to be detected. In addition to the size of the paper or in addition to the size of the paper, the guide state may be determined in advance for each combination of paper color and / or material. In this case, if any of the plurality of sub-conveying paths SP1 to SP3 is selected based on the detected sheet size, color, material, etc., the sub-conveying path to be selected, the sheet size, color and The guide member 350 is set in a predetermined guide state with respect to. The same applies to the fourth embodiment.

  In the first to third embodiments, the paper feed unit 150 of the MFP 100 is provided with three sub conveyance paths SP1, SP2 and SP3. However, the main conveyance path 41 may be provided with two sub conveyance paths. In addition, four or more secondary transfer paths may be provided. In this case, the guiding device 300 is configured to be able to shift to a plurality of guiding states at least equal to the number of secondary conveyance paths.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

  13 upper end portion, 15 discharge roller, 30 lower end portion, 41 main conveyance path, 45 timing roller, 47, 53Y transfer roller, 49 fixing roller, 51Y, 51M, 51C, 51K image forming unit, 55 driving roller, 55A roller, 57 Intermediate transfer belt, 59 detection device, 59a light projection unit, 59b light receiving unit, 61 print data generation unit, 62 image formation control unit, 63 sheet information acquisition unit, 64 path selection unit, 65, 65A size selection unit, 66 Guidance state switching unit, 100 MFP, 101 side wall, 110 main circuit, 111 CPU, 112 communication interface (I / F) unit, 113 ROM, 114 RAM, 115 HDD, 116 facsimile unit, 118 external storage device, 118 A CD-ROM , 120 automatic document feeder 125 document tray, 127 document discharge tray, 130 document reading unit, 140 image forming unit, 150 sheet feeding unit, 151, 152, 153 sheet feeding tray, 151r to 154r sheet feeding roller, 152a, 153a conveying path, 154 manual feeding tray 159 output tray, 160 operation panel, 161 display unit, 163 operation unit, 165 touch panel, 167 hard key unit, 300 guide device, 310, 350 guide member, 311, 351 first guide surface, 312, 352 second Guide surface, 320 drive shaft, 330 motor, 340 drive circuit, 360 first regulating member, 370 second regulating member, B1, B2 path forming member, DA detection area, K arrow, SP1, SP2, SP3 secondary conveyance Path, TP target position, d1, d2 distance, pa paper.

Claims (9)

With multiple secondary transport routes,
Main transport paths connected to the plurality of secondary transport paths;
A detection unit having a detection area in the main transport path, and detecting information on the recording medium as medium information while the recording medium is moving the detection area;
Even when the recording medium enters the main conveyance path from any of the plurality of secondary conveyance paths, the recording medium is guided such that the recording medium moves a predetermined target position in the detection area. An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein the guiding unit has a contact guiding surface that contacts at least a part of one surface of the recording medium entering the main conveyance path from any of the plurality of secondary conveyance paths. . The image forming apparatus according to claim 2, wherein the detection area is set at a position separated by 10 mm or less from the downstream end of the contact guide surface by more than 0 mm in the conveyance direction of the recording medium. The plurality of secondary transport paths include first and second secondary transport paths,
The contact guide surface includes a first guide surface and a second guide surface facing each other,
The guiding means is located between the first sub-conveying path and the second sub-conveying path, and the recording medium having moved through the first sub-conveying path is sent to the main conveying path. When one surface of the recording medium comes in contact with the first guide surface, and the recording medium moved on the second sub-conveying path is sent to the main conveyance path, the one surface of the recording medium is the second guiding surface The image forming apparatus according to claim 2, wherein the image forming apparatus is provided in contact with the image forming apparatus. The system further comprises path selection means for selecting one of the plurality of secondary conveyance paths.
The image forming apparatus according to claim 4, wherein the guiding unit is configured to be able to shift to a guiding state determined in advance with respect to the selected secondary conveyance path. Route selection means for selecting one of the plurality of secondary conveyance routes;
And a size selection means for selecting the size of the recording medium,
5. The image forming apparatus according to claim 4, wherein the guiding unit is configured to be capable of transitioning to a guiding state predetermined for a combination of the selected secondary conveyance path and the size of the selected recording medium. The plurality of secondary transport paths include first and second secondary transport paths,
The guiding means is
An elastically deformable guide member having a first guide surface and a second guide surface facing each other as the contact guide surface;
A first member disposed at a position opposite to the first guide surface of the guide member and restricting elastic deformation of the guide member in a direction toward which the second guide surface faces to a predetermined first range. A regulating member,
A second member disposed at a position facing the second guide surface of the guide member and restricting the elastic deformation of the guide member in a direction toward the first guide surface to a predetermined second range. Including a regulating member,
The guide member is located between the first sub-transport path and the second sub-transport path, and the recording medium having moved through the first sub-transport path is sent to the main transport path. When the recording medium is in contact with the first guide surface and the recording medium moved on the second auxiliary transport path is sent to the main transport path, the recording medium is in contact with the second guide surface. The image forming apparatus according to claim 2, provided in A transport route,
A detection unit that has a detection area in the transport path, and detects information related to the recording medium as medium information during movement of the detection area of the recording medium transported through the transport path;
Guiding means for guiding the recording medium moving on the conveyance path such that the recording medium moving on the conveyance path moves a predetermined target position in the detection area;
And size selection means for selecting the size of the recording medium,
The image forming apparatus, wherein the guiding unit includes a guiding member configured to be able to shift to a guiding state predetermined for the size of the selected recording medium. The recording medium is paper,
The medium information includes information indicating the paper basis weight,
The detection means
A light projecting unit that emits light to the detection area;
A light receiving unit that outputs a signal according to the amount of light received by receiving light from the detection area;
The image forming apparatus according to any one of claims 1 to 8, further comprising: an acquiring unit that acquires a basis weight of a sheet based on an output signal of the light receiving unit.

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