JP2011057384A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stop paper at an adequate position corresponding to the type of the paper. <P>SOLUTION: A printer includes a first added paper feeding part which includes a first driving motor, a first paper feeding roller for picking out accumulated paper, a first carrying roller to be rotated with the rotation of the first driving motor for carrying the paper carried by the first paper feeding roller, a drive control part 203 for controlling the first driving motor, and a load detecting part 201 for detecting the load of the first driving motor. The drive control part 203 includes a stop timing determining part 205 for determining a stop timing for stopping the first driving motor in accordance with the detected load to stop the paper carried by the first carrying roller at a predetermined position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus that forms an image on a sheet stored in an added sheet feeding tray.

  The image forming apparatus takes out a plurality of sheets stored in a sheet feeding tray one by one, and forms an image on the sheet while the taken out sheet is being conveyed. The paper stored in the paper feed tray is transported along a transport path by a roller rotated by a motor. On the other hand, the paper feed tray can store a plurality of types of paper. However, since the paper size, weight, and the like differ depending on the type, the load on the motor differs depending on the type of paper, and the conveyance speed for conveying the paper varies. . For this reason, the size, basis weight, and other types of paper stored in the paper feed tray are preset in the image forming apparatus, and the rotation of the rollers is controlled according to the settings.

  Japanese Laid-Open Patent Publication No. 2007-55710 discloses a recording in which a plurality of recording papers are mounted in preparation for a case where an image forming apparatus is erroneously set to a paper type that is actually stored in a paper feed tray. A paper loading means, a paper feed roller for feeding recording paper, a paper feed sensor provided on the paper transport path, a time measuring means capable of measuring time, and the paper feed roller using the time measuring means. If the time until the paper feed sensor detects the recording paper within a certain time after the rotation starts, it is determined that the recording paper loaded by the recording paper loading means is not correctly loaded and the recording paper is correctly loaded. Thus, there is described an image forming apparatus provided with warning means for issuing a warning to a user.

On the other hand, it is conceivable to use a stepping motor in order to reduce variations in the time for conveying a stationary sheet until it reaches a predetermined speed. However, the stepping motor cannot recover from the step-out when its characteristics are out of rotation synchronization. For this reason, the current flowing through the stepping motor must be set taking into consideration the condition with the largest load so as not to step out. Therefore, even when the load is small, the motor is driven with a large current and the efficiency is poor. is there. This problem can be solved by using a direct current (DC) brushless motor. However, as a characteristic of the DC brushless motor, the start / stop time is changed due to a change in load, so that the paper transport distance is In order to control the paper and to stop the paper at an appropriate position, a clutch must be provided between the DC brushless motor and the transport roller, which increases the cost.
JP 2007-55710 A

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide an image forming apparatus capable of stopping paper at an appropriate position corresponding to the type of paper. It is to be.

  Another object of the present invention is to provide an image forming apparatus capable of appropriately controlling a distance for conveying a sheet.

  In order to achieve the above-described object, according to one aspect of the present invention, an image forming apparatus rotates with the rotation of a driving unit, a taking-out unit for taking out accumulated paper, and the driving unit, and is conveyed by the taking-out unit. And a drive control means for controlling the drive means, and a load detection means for detecting the load on the drive means. In order to stop at the position, stop timing determining means for determining a stop timing for stopping the driving means based on the detected load is included.

  According to this aspect, the load of the driving unit varies depending on the type of paper conveyed by the conveying unit, and when the load is different, the time from when the driving unit is stopped to when the conveying unit stops is different. Since the stop timing for stopping the drive unit is determined based on the load of the drive unit, the distance for transporting the sheet until the transport unit stops can be appropriately controlled. Therefore, it is possible to provide an image forming apparatus capable of stopping the paper at an appropriate position corresponding to the type of paper.

  Preferably, the image forming unit that forms an image on the sheet conveyed by the conveying unit, and the image forming unit and the conveying unit are provided between the image forming unit and the image forming unit. And a first detection unit that is provided between the supply unit and the conveyance unit and detects the presence / absence of a sheet, and the stop timing determination unit detects the sheet by the first detection unit. Stop time determining means for determining a time from when the driving means is stopped to when the drive means is stopped.

  According to this aspect, driving is performed after the sheet is detected by the first detection unit that is provided between the supply unit and the conveyance unit provided between the image forming unit and the conveyance unit and detects the presence or absence of the sheet. The time until the stop timing for stopping the means is determined. When the load is different, the time from when the driving unit is stopped to when the conveying unit stops is different. Since the time from the detection of the sheet to the stop timing for stopping the driving unit is determined by the first detection unit, the sheet can be stopped while the sheet is curved between the supply unit and the conveyance unit. As a result, the inclination of the sheet conveyed by the conveying unit can be corrected by the supplying unit.

  Preferably, the drive control means further includes drive timing determination means for determining a re-drive timing for driving the drive means next after stopping the drive means based on the detected load.

  According to this aspect, after the driving unit is stopped, the re-drive timing for driving the driving unit next is determined based on the detected load. When the load of the driving means is different, the time from the state where the conveying means is stopped to the predetermined number of revolutions is different. Since the driving timing for re-driving the driving unit is determined based on the load of the driving unit, the distance for conveying the sheet can be appropriately controlled from the state where the conveying unit is stopped.

  Preferably, the image forming unit that forms an image on the sheet conveyed by the conveying unit, and the image forming unit and the conveying unit are provided between the image forming unit and the image forming unit. And a drive timing determination unit that includes a drive time determination unit that determines a time from a re-drive timing to a timing at which the supply unit starts conveyance to the image forming unit.

  According to this aspect, the time from the re-drive timing to the timing at which the supply unit starts transporting to the image forming unit is determined. For this reason, the length of the sheet can be maintained at a predetermined length or more between the supply unit and the conveyance unit, and the sheet can be prevented from being pulled by the supply unit and the conveyance unit.

  Preferably, the load detecting means determines the load based on a rotational speed detecting means for detecting the rotational speed of the driving means and a driving state of the driving means from when the driving means is driven until the predetermined rotational speed is reached.

  According to this aspect, since the drive state of the drive unit from when the drive unit is driven until the predetermined number of rotations is detected, the load on the drive unit can be detected more quickly and reliably.

  Preferably, a clutch is provided between the drive means and the take-out means and switches the power transmission of the drive means, and the drive control means drives the drive means when the take-out means takes out the first sheet. At the same time or slightly after that, the clutch is engaged, and the load detection means determines the load based on the drive state of the drive means from when the clutch is engaged until the drive means reaches a predetermined rotational speed.

  According to this aspect, the load is determined based on the driving state when the driving means is driven and the power is transmitted to the take-out means and the conveying means. Since the drive state when the load of the drive unit is the maximum from the state where the drive unit is stopped to the predetermined rotational speed is detected, the drive state can be detected accurately.

  Preferably, a size acquisition unit that acquires the size of the paper stored in the paper feed tray, a remaining amount detection unit that detects the remaining amount of paper stored in the paper feed tray, and a A basis weight acquisition means for acquiring a basis weight predetermined as the basis weight, and within a predetermined range from a predetermined reference load with respect to the detected paper size, paper remaining amount and basis weight. The apparatus further includes determination means for determining whether or not the load of the driving means detected by the load detection means is included.

  According to this aspect, the load of the driving means detected by the load detecting means is included within a predetermined range from a predetermined reference load with respect to the detected paper size, paper remaining amount and paper basis weight. To determine whether or not Since the load on the driving unit varies depending on the size of the sheet, the remaining amount of the sheet, and the basis weight of the sheet, the reference load can be determined in advance. If the load of the driving means detected by the load detecting means is not within a predetermined range from the reference load, it can be detected that the predetermined basis weight of the paper is incorrect.

  Preferably, when the determination unit determines that the load of the driving unit detected by the load detection unit is not included within a predetermined range from the reference load, a notification unit that notifies that the basis weight setting is incorrect is provided. And further.

  Preferably, the storage unit stores a reference table in which the relationship between the load of the driving unit, the paper size, the basis weight of the paper, and the remaining amount of the paper is predetermined, and the load is detected within a predetermined range from the reference load by the determination unit If it is determined that the load of the drive means detected by the means is not included, based on the load detected by the load detection means, the paper size, the paper basis weight, and the paper remaining amount related by the reference table And setting determination means for determining a combination of the two.

  According to this aspect, the combination of the paper size, the paper basis weight, and the remaining paper amount related by the reference table is determined based on the load detected by the load detecting means. The correct basis weight can be determined.

  Preferably, the image forming unit further includes a setting change unit that changes a preset basis weight based on the basis weight of the paper determined by the combination determined by the setting determination unit, and the image forming unit changes the basis weight by the setting change unit. If so, an image is formed under image forming conditions corresponding to the basis weight after the change.

  According to this aspect, the preset basis weight is changed by the basis weight of the paper determined by the determined combination, and an image is formed under the image forming conditions corresponding to the changed basis weight. For this reason, an image can be formed under appropriate image forming conditions.

  Preferably, the apparatus further includes a size detection unit that detects the size of the paper stored in the paper feed tray, and a remaining amount detection unit that detects the remaining amount of the paper stored in the paper feed tray. Is a combination of the load detected by the load detection means and the paper size, paper basis weight, and remaining amount of paper related by the reference table, and the detected paper size and remaining amount of paper. Determine a set associated with the load closest to the load detected by the load detecting means from among a plurality of combinations.

  Preferably, the load detection unit includes a size acquisition unit that acquires the size of the paper stored in the paper feed tray, a remaining amount detection unit that detects the remaining amount of paper stored in the paper feed tray, and a paper feed tray. The relationship between the basis weight acquisition means for acquiring the basis weight of the stored paper and the detected paper size, paper remaining amount and basis weight, and the relationship between the paper size, paper basis weight and paper remaining amount in advance. The motor load is determined with reference to the determined reference table.

  According to this aspect, the load on the driving unit varies depending on the size of the paper, the remaining amount of the paper, and the basis weight, but the load on the driving unit is determined by detecting them. Can be detected.

  Preferably, a clutch that is provided between the driving unit and the taking-out unit and that switches the power transmission of the driving unit, and a second detecting unit that is provided between the taking-out unit and the conveying unit and detects the presence or absence of paper. In addition, the drive control means includes a measuring means for measuring the time from when the clutch is engaged and after the predetermined time has elapsed, the clutch is released, and when the second detection means detects the sheet, and at the measured time. And a connection timing determining means for determining a connection timing for connecting the clutch next after the sheet detected by the second detecting means is no longer detected.

  According to this aspect, the time from when the clutch is engaged to when the sheet is conveyed between the take-out means and the conveyance means is measured, and based on the measured time, the connection timing for the next clutch is determined. The For this reason, it is possible to correct the deviation of the stored paper.

  Preferably, a plurality of additional sheet feeding units each including a driving unit, a taking-out unit, a conveying unit, a driving control unit, and a load detecting unit are arranged to overlap each other, and the plurality of additional sheet feeding units are supplied A most downstream additional paper feeding means closest to the means, a most upstream additional paper feeding means for supplying paper, and at least one intermediate additional paper feeding means between the most downstream additional paper feeding means and the uppermost upstream paper feeding means, The transport means included in the most downstream additional paper feed means transports the paper transported from the upstream to the supply means, and the transport means included in the most upstream additional paper feed means receives the paper transported from the paper feed roller. The transport means of the at least one intermediate additional paper feed means has the upstream one, and the transport means of each of the at least one intermediate additional paper feed means has the downstream intermediate additional paper supplied from the upstream. Paper means or expansion Each of the plurality of load detecting means detects a load for each driving means included in each of the plurality of additional paper feeding means, and the stop timing determining means included in the plurality of drive control means is The stop timing for stopping the driving means included in each of the plurality of additional paper feeding means is determined based on the load detected for the driving means.

  According to this aspect, the stop timing for stopping the driving means included in each of the plurality of additional paper feeding means is determined based on the load detected for the driving means. The paper can be stopped at the correct position.

  Preferably, the drive timing determination unit included in the drive control unit determines a redrive timing for redriving the drive unit included in each of the plurality of additional paper feed units based on a load detected for the drive unit.

  According to this aspect, the re-drive timing for re-driving the driving means included in each of the plurality of additional paper feeding means is determined based on the load detected for the driving means. The distance for conveying the sheet can be appropriately controlled from the state where the conveying means is stopped.

  Hereinafter, embodiments 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 thereof will not be repeated.

  FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a printer according to one embodiment of the present invention. Referring to FIG. 1, the printer 1 includes a main body 10 and first to fourth additional paper feeding units 50, 50A, 50B, and 50C that are detachable from the main body.

  The main body 10 includes a control board 11 for controlling the entire printer 1, an image forming unit 12, and a main body paper feeding unit 20. The image forming unit 12 includes image forming units 19A, 19B, 19C, and 19D corresponding to yellow, magenta, cyan, and black, a transfer belt 17, a driving roller 13, a driven roller 15, a transfer roller 35, and fixing. And a roller 37.

  The transfer belt 17 is suspended by the driving roller 13 and the driven roller 15 so as not to be loosened. When the driving roller 13 rotates counterclockwise in the figure, the transfer belt 17 rotates counterclockwise in the figure at a predetermined speed. As the transfer belt 17 rotates, the driven roller 15 rotates counterclockwise.

  The image forming units 19A, 19B, 19C, and 19D receive yellow, magenta, cyan, and black printing data, respectively, and at least one of them is driven to form a toner image on the transfer belt 17. When all of the image forming units 19A, 19B, 19C, and 19D are driven, a full color image is formed. The timing at which each of the image forming units 19A, 19B, 19C, and 19D transfers the toner image onto the transfer belt is adjusted by detecting a reference mark attached to the transfer belt 17. Note that the image forming units 19A, 19B, 19C, and 19D are each integrally configured and detachable from the main body 10.

  The main body paper feed unit 20 includes a main body paper feed tray 21 in which paper is stored, a main body push-up plate 22, a main body paper feed roller 23, a main body paper regulation plate 25, a main body paper remaining amount detection sensor 27, and a main body empty. A sensor 29, a timing roller (supply means) 31, and a timing sensor 33 are included. The main body paper regulating plate 25 is adjusted to a position corresponding to the size of the paper stored in the main body paper feed tray 21 and supports the paper so that the paper does not shift. When the position of the main body paper regulation plate 25 is adjusted, the main body paper regulation plate 25 is connected to any one contact of the main body size detection switch having a plurality of contacts respectively arranged according to a plurality of sizes of paper. In the control board 11, the size of the paper is detected by specifying the contact that is turned on among the plurality of contacts of the main body size detection switch.

  The main body sheet remaining amount detection sensor 27 includes a variable resistor and is connected to the control board 11. The main body paper remaining amount detection sensor 27 is connected to the main body push-up plate 22 and changes its resistance depending on the position of the main body push-up plate 22 that changes according to the remaining amount of paper. The control board 11 detects the voltage at both ends of the main body paper remaining amount detection sensor 27, and detects the remaining amount of paper stored in the main body paper feed tray 21 from the position of the main body push-up plate 22. The main body empty sensor 29 is, for example, a proximity switch, and is connected to the control board 11. The control board 11 detects the presence or absence of paper stored in the main body paper feed tray 21 from the output of the main body empty sensor 29. Further, as the main body empty sensor 29, a sensor in which an infrared light emitting element and an infrared light receiving element are combined may be used.

  The paper stored in the main body paper feed tray 21 is pushed upward by the main body push-up plate 22 and pressed against the main body paper feed roller 23. When the main body feed roller 23 rotates due to friction between the main body feed roller 23 and the sheet, the uppermost sheet of the stacked sheets passes through a path connecting from the main body feed tray 21 to the timing roller 31, It is conveyed to the timing roller 31.

  The timing sensor 33 is provided upstream of the timing roller 31 in the sheet flow path, and detects the presence or absence of the sheet. The timing sensor 33 outputs an ON signal while detecting a sheet, and outputs an OFF signal when not detecting a sheet.

  The timing roller 31 starts to rotate in synchronization with the rotation of the transfer belt 17 and conveys the sheet to the transfer belt 17. The sheet is pressed against the transfer belt 17 by the transfer roller 35, and the toner image formed on the transfer belt 17 is transferred onto the sheet.

  The sheet on which the toner image is transferred is conveyed to the fixing roller 37 and heated by the fixing roller 37. As a result, the toner is melted and fixed on the paper. Thereafter, the paper is discharged to a paper discharge tray at the top of the main body.

  Since the first to fourth additional paper feeding units 50, 50A, 50B, and 50C have the same configuration, the first additional paper feeding unit 50 will be described as an example unless otherwise specified. In addition, the code | symbol of the member which each 1st-4th additional paper supply part 50, 50A, 50B, 50C has, shows the member which the 1st additional paper supply part 50 has only with a number, and the 2nd-4th additional paper supply The reference numerals assigned to the members included in the sections 50A, 50B, and 50C are the same members as those included in the first additional sheet feeding section 50, with the same numerals followed by the letters A, B, and C respectively. ing.

  The first additional paper feeder 50 includes a first additional board 51 that controls the entire first additional paper feeder 50, a first drive motor (drive means) 53, and a first paper feed tray 61 that stores paper. The first push-up plate 62, the first paper feed roller (extraction means) 23 for taking out the paper stored in the first paper feed tray 61, the first clutch 64 and the paper fed by the first paper feed roller 63. A transport roller (transport means) 71 for transporting paper, a transport sensor (second detection means) 73 for detecting the presence or absence of paper, a first push-up plate 62, a first paper regulating plate 65, and a first paper remaining amount detection. A sensor 67 and a first empty sensor 69 are included.

  The first drive motor is a power source for rotating the first paper feed roller 63 and the first transport roller 71, and a direct current (DC) brushless motor is used here. When the load is different, the DC brushless motor has a specification in which the time from the stopped state to the rotation to the predetermined number of rotations is different. In this example, a DC brushless motor is used as an example of the first drive motor. However, if the motor has a specific specification in which the time from the stopped state to the predetermined rotational speed is different from the stopped state when the load is different. Another motor may be used.

  The first clutch 64 is provided between the first drive motor 53 and the first paper feed roller 63 and switches the power transmission of the first drive motor 53. The conveyance roller 71 is connected to the first drive motor 53 with a gear or a belt, rotates with the rotation of the first drive motor 53, and conveys the sheet conveyed by the first paper feed roller 63. The first transport sensor 73 is provided between the first paper feed roller 63 and the transport roller 71 and detects the presence or absence of paper transported from the first paper feed roller 63.

  The first paper restriction plate 65, the first paper remaining amount detection sensor 67, and the first empty sensor 69 are the same as the main body paper restriction plate 25, the main body paper remaining amount detection sensor 27, and the main body empty sensor 29. Do not repeat.

  The paper stored in the first paper feed tray 61 is pushed upward by the first push-up plate 62 and pressed against the first paper feed roller 63. When the first paper feed roller 63 rotates due to the friction between the first paper feed roller 63 and the paper, the uppermost sheet of the stacked paper is transferred from the first paper feed tray 61 to the first transport roller 71. Be transported. Further, the sheet is conveyed to the timing roller 31 through a path connected to the timing roller 31 by the rotation of the first conveyance roller 71.

  The paper stored in the second paper feed tray 61A of the second additional paper feeder 50A is transported from the second paper feed tray 61A to the second transport roller 71A by the rotation of the second paper feed roller 63A. The Further, the sheet is conveyed to the first conveyance roller 71 through a path connected to the first conveyance roller 71 by the rotation of the second conveyance roller 71A. In this case, the sheet is conveyed to the timing roller 31 through a path connected to the timing roller 31 by the rotation of the first conveyance roller 71.

  The paper stored in the third paper supply tray 61B of the third additional paper supply unit 50B is conveyed from the third paper supply tray 61B to the third conveyance roller 71B by the rotation of the third paper supply roller 63B. The Further, the rotation of the third transport roller 71B causes the sheet to be transported to the second transport roller 71A via a path connected to the second transport roller 71A. In this case, the sheet is conveyed to the timing roller 31 through a path connecting to the timing roller 31 as the second conveyance roller 71A and the first conveyance roller 71 rotate.

  The paper stored in the fourth paper feed tray 61C of the fourth additional paper feeder 50C is transported from the fourth paper feed tray 61C to the fourth transport roller 71C by the rotation of the fourth paper feed roller 63C. The Further, the sheet is transported to the second transport roller 71A through a path connected to the third transport roller 71B by the rotation of the fourth transport roller 71C. In this case, the sheet is conveyed to the timing roller 31 through a path connecting to the timing roller 31 by the rotation of the third conveyance roller 71B, the second conveyance roller 71A, and the first conveyance roller 71.

  FIG. 2 is a block diagram illustrating an example of a schematic hardware configuration of the control board 11. Referring to FIG. 2, the control board 11 includes a main CPU 101, a storage unit 103, a card I / F 105, a communication I / F 109, a network interface (I / F) 111, each connected to the bus 110. And an operation panel 113.

  The main CPU 101 controls the entire control board 11. A communication I / F 109 connects the printer 1 to a personal computer. A communication I / F 109 communicates with a personal computer and receives print data for forming an image from the personal computer. A network I / F 111 connects the printer 1 to a network. The network I / F 111 outputs data to the network according to a predetermined communication protocol, and receives data from the network according to the predetermined communication protocol. The main CPU 101 can receive print data from another computer connected to the network via the network I / F 111. For this reason, the printer 1 receives print data from either a computer connected via the communication I / F 109 or a computer connected via the network I / F 111 and forms an image.

  Operation panel 113 includes an input unit 113A and a display unit 113B. The input unit 113 </ b> A is an input device such as a touch panel, a keyboard, or a mouse for receiving an operation input by the user of the printer 1. The display unit 113B is a liquid crystal display device or an organic EL (electro-luminescence) display panel. In the case where a touch panel made of a transparent member is used for the input unit 113A, the instruction of the button displayed on the display unit 113B can be detected by placing the touch panel on the display unit 113B. Thereby, various operations can be input.

  The storage unit 103 includes a semiconductor memory such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an EEPROM (Electrically Erasable / Programmable ROM), and a magnetic storage device such as a hard disk drive (HDD).

  The main CPU 101 executes a program stored in a ROM included in the storage unit 103. Here, an example is shown in which the main CPU 101 executes a program stored in the ROM of the storage unit 103, but the program executed by the main CPU 101 is not limited to the one stored in the ROM, and may be stored in the EEPROM. Good. If stored in the EEPROM, the program can be rewritten or additionally written. For this reason, another computer connected to the network can rewrite the program stored in the EEPROM of the printer 1 or can write a new program. Further, the printer 1 can download a program from another computer connected to the network and store the program in the EEPROM.

  A memory card 105A is attached to the card I / F 105. The main CPU 101 can access the memory card 105A via the card I / F 110. The program may be stored in the memory card 105A, and the main CPU 101 may load and execute the program recorded on the memory card 105A attached to the card I / F 105. The recording medium for recording the program is not limited to the memory card 105A, and other recording media may be used. The program here includes not only a program directly executable by the main CPU 101 but also a program in a source program format, a compressed program, an encrypted program, and the like.

  FIG. 3 is a block diagram illustrating an outline of a first extension control board included in the first extension sheet feeding unit. Referring to FIG. 3, the first extension control board 51 includes a first CPU 81 that controls the entire first extension sheet feeding unit 50, a first ROM 83 that stores a program executed by the first CPU 81, and a work area for the first CPU 81. And a first RAM 85 to be used. The first CPU 81 is connected to the first drive motor 53 and controls the first drive motor 53. Specifically, a drive start signal is output to the first drive motor 53 to rotate the first drive motor 53, and a drive stop signal is output to stop the rotation of the first drive motor 53. Further, the first CPU 81 receives the rotational speed (angular velocity) from the first drive motor 53 and detects the angular acceleration of the first drive motor 53.

  The first CPU 81 is connected to the first clutch 64 and controls opening and closing of the first clutch 64. Specifically, the first CPU 81 outputs an ON signal to the first clutch 64 to close the first clutch. While the first clutch 64 is closed, the power of the first drive motor 53 is transmitted to the first paper feed roller 63. Further, the first CPU 81 outputs the OFF signal to the first clutch 64 to open the first clutch 64. While the first clutch 64 is open, the power of the first drive motor 53 is not transmitted to the first paper feed roller 63.

  The first CPU 81 is connected to the first remaining paper amount detection sensor 67. The first sheet remaining amount detection sensor 67 includes a variable resistor, is connected to the first push-up plate 62, and the resistance changes depending on the position of the first push-up plate 62 that changes according to the remaining amount of the sheet. The first CPU 81 detects the voltage across the first paper remaining amount detection sensor 67 and detects the remaining amount of paper stored in the first paper feed tray 61 from the position of the first push-up plate 62. The first CPU 81 is connected to the first empty sensor 69 and detects the presence / absence of paper stored in the first paper feed tray 61 from the output of the first empty sensor 69.

  The first CPU 81 is connected to the first transport sensor 73. The first conveyance sensor 73 outputs an ON signal while detecting a sheet, and outputs an OFF signal when not detecting a sheet. The first CPU 81 detects a change in the output of the first conveyance sensor 73 from OFF to ON, thereby detecting that the leading edge of the sheet is at a position where the first conveyance sensor 73 is disposed, and the first conveyance sensor 73. By detecting the change in the output from ON to OFF, it is detected that the trailing edge of the sheet is at the position where the first conveyance sensor 73 is disposed.

  The first CPU 81 is connected to the first size detection switch 66. The first size detection switch 66 has a plurality of contacts arranged according to the size of the paper stored in the first paper feed tray 61. When the first paper restricting plate 65 is positioned according to the size of the paper, one of the plurality of contacts of the first size detecting switch 66 corresponding to the position of the first paper restricting plate 65 is turned on. The first CPU 81 detects the size of the paper by specifying the contact that is turned on among the plurality of contacts of the first size detection switch 66.

  FIG. 4 is a diagram illustrating an example of a change in the rotation speed when the first drive motor is activated. FIG. 5 is a diagram illustrating an example of a change in the rotation speed when the first drive motor is stopped. 4 and 5, the change in the rotation speed when the first drive motor receives a reference load is indicated by a solid line, and the change in the rotation speed when the first drive motor receives a load smaller than the reference is indicated by a dotted line. The change in the rotational speed when the first drive motor receives a load larger than the reference is indicated by a one-dot chain line. Referring to FIG. 4, the time until the first drive motor 53 reaches a predetermined number of revolutions at the time of startup is in the order of when the load is smaller than the reference, when the load is the reference, and when the load is greater than the reference become longer. Referring to FIG. 5, the time from the predetermined rotation speed until the rotation stops at the time of stopping becomes longer in the order of when the load is larger than the reference, when the load is the reference, and when the load is smaller than the reference.

  The first drive motor 53 has a different time for reaching a predetermined rotational speed depending on the load at the time of startup and a time for stopping from the predetermined rotation at the time of stop. For this reason, the printer 1 in the present embodiment controls the driving of the first drive motor 53 so that the sheet is not pulled between the timing roller 31 and the first transport roller 71.

  FIG. 6 is a block diagram illustrating an example of each of the functions of the first CPU 81 and the functions of the main CPU 101. The functions of the first CPU 81 and the functions of the main CPU 101 are realized by the first CPU 81 executing the program stored in the first ROM 83 and the main CPU 101 executing the program stored in the storage unit 103. . FIG. 7 is a timing chart for explaining the start and stop of the drive motor. Hereinafter, the paper supply when the printer 1 forms an image will be described with reference to FIGS. 6 and 7.

  The main CPU 101 includes a first detection unit 121, a timing roller control unit 123, an image formation control unit 125, a notification unit 133, a setting determination unit 135, and a setting change unit 137. The image formation control unit 125 controls the image formation unit 12 and outputs an image writing signal to the timing roller control unit 123. The image writing signal is a signal serving as a reference for the image formation control unit 125, and the transfer belt 17 rotates based on the image writing signal.

  The timing roller control unit 123 starts the rotation of the timing roller 31 by switching the timing clutch from OFF to ON based on the image writing signal input from the image formation control unit 125, and switches the timing clutch from ON to OFF. The rotation of the timing roller 31 is stopped by switching. Further, the timing roller control unit 123 outputs an image writing signal to the first CPU 81. The timing roller control unit 123 starts rotating the timing roller 31 in synchronization with the image writing signal, specifically, after a predetermined time has elapsed since the image writing signal was input. Therefore, the image writing signal can be said to be a signal indicating the timing at which the timing roller 31 starts to rotate.

  The first detection unit 121 receives the output of the timing sensor 33 and detects the change of the output of the timing sensor 33 from OFF to ON. In other words, the position where the timing sensor 33 is disposed at the leading edge of the sheet. It detects that it is in the vicinity of the upstream of the timing roller 31. The first detection unit 121 outputs a first detection signal to the first CPU 81 when detecting that the leading edge of the sheet is at the position where the timing sensor 33 is disposed.

  The first CPU 81 includes a load detection unit 201 that detects a load of the first drive motor 53, a drive control unit 203 that controls the first drive motor 53, a clutch control unit 213 that controls the first clutch 64, and a first conveyance. A second detection unit 217 to which the output of the sensor 73 is input and a measurement unit 215 that measures time are included.

  The load detection unit 201 detects a load when the first drive motor 53 is activated. FIG. 8 is a block diagram illustrating detailed functions of the load detection unit 201. Referring to FIG. 8, load detection unit 201 includes a rotation speed detection unit 251 and a drive state detection unit 253. The rotation speed detector 251 receives the rotation speed of the first drive motor 53 and outputs the rotation speed to the drive state detector 253. The drive state detection unit 253 detects the load when the first drive motor 53 is activated by measuring the angular acceleration or time from when the first drive motor 53 starts to rotate until it reaches a predetermined rotational speed. Here, the time of starting refers to a period in which the first clutch 64 is ON before the first driving motor 53 starts rotating and before reaching a predetermined rotational speed. That is, the first drive motor 53 rotates the first paper feed roller 63 and the first transport roller 71 and transports the paper. Since the load on the first drive motor 53 at the time of startup becomes the largest, by detecting the load during this period, it is possible to accurately detect the difference in load that varies depending on the paper. When the first paper feed roller 63 and the first transport roller 71 are transporting paper, the load on the first drive motor 53 varies depending on the weight of the paper or the friction of the stacked paper. Here, a case where the load of the first drive motor 53 at the time of activation is an angular acceleration will be described as an example. The load detection unit 201 detects a change (v1) in the rotational speed of the drive motor at a predetermined time t1 at the time of activation, calculates an angular acceleration (R), and outputs the angular acceleration (R) to the drive control unit 203 and the main CPU 101. However, R = v1 / t1.

  Returning to FIG. 6 and FIG. 7, the drive control unit 203 starts driving the first drive motor 53 by switching the first drive motor 53 from OFF to ON, and switches the first drive motor 53 from ON to OFF. By switching, the driving of the first drive motor 53 is stopped. The drive control unit 203 activates the first drive motor 53 based on the image writing signal input from the timing roller control unit 123. When the first control sheet is conveyed, the drive control unit 203 first passes through the first drive motor 53 after a predetermined time has elapsed since the image writing signal input from the timing roller control unit 123 switches from OFF to ON. Start up.

  The clutch control unit 213 controls the rotation of the first paper feed roller 63 by switching the first clutch 64 between ON and OFF. The clutch control unit 213 receives the image writing signal from the timing roller control unit 123, switches the first clutch 64 from OFF to ON based on the image writing signal, and rotates the first paper feeding roller 63. When transporting the first first sheet, the clutch control unit 213 turns off the first clutch 64 after a predetermined time has elapsed since the image writing signal input from the timing roller control unit 123 switches from OFF to ON. Switch from ON to ON.

  The timing at which the clutch control unit 213 switches the first clutch from OFF to ON is several ms later than the timing at which the drive control unit 203 switches the first drive motor 53 from OFF to ON. This is because, due to the characteristics of the first clutch 64, the connection time is more stable when connected while rotating. The timing at which the clutch control unit 213 switches the first clutch from OFF to ON may be the same as or before the timing at which the drive control unit 203 switches the first drive motor 53 from OFF to ON.

  The clutch control unit 213 turns off the first clutch 64 and releases it after a predetermined time after the first clutch 64 is turned on and engaged, and stops the driving of the first paper feed roller 63. The predetermined time is a time until at least the sheet reaches the first transport roller 71. When the first clutch 64 is switched from ON to OFF, the first paper feed roller 63 stops driving, but the paper is transported by the first transport roller 71, so the first paper feed roller 63 is transported. Followed by. The clutch control unit 213 outputs an extraction start signal to the measurement unit 215 when turning on the first clutch 64.

  When the output of the first transport sensor 73 is input and the second detection unit 217 detects a change from the OFF state to the ON state, the second detection unit 217 outputs a tip detection signal to the measurement unit 215, and the first transport unit 73 When the output of the sensor 73 detects a change from ON to OFF, a rear end detection signal is output to the clutch control unit 213.

  The measurement unit 215 measures the time from when the extraction start signal is input from the clutch control unit 213 to when the tip detection signal is input from the second detection unit 217, and outputs the measured time t11 to the clutch control unit 213. .

  Based on the time t11 input from the measurement unit 215, the clutch control unit 213 receives a time from when the rear end detection signal is input from the second detection unit 217 until the next timing of switching the first clutch 64 from OFF to ON. t41 is determined. Since the first drive motor 53 is rotated at a predetermined rotation speed, the second and subsequent sheets are taken out little by turning on the first clutch 64. The time t11 indicates a shift in the paper position in the first paper feed tray 61, and the time t41 is a time for correcting this shift. Here, ½ of the deviation from the reference value tPS is corrected.

  The clutch control unit 213 switches the first clutch 64 from OFF to ON after a corrected time t41 after the rear end detection signal is input from the second detection unit 217. As a result, the interval between continuously conveyed sheets can be made as equal as possible.

  The drive control unit 203 includes a stop timing determination unit 205 and a drive timing determination unit 209. The stop timing determination unit 205 stops the first drive motor 53 based on the angular acceleration R input from the load detection unit 201 in order to stop the sheet conveyed by the first conveyance roller 71 at a predetermined position. Determine timing. The stop timing determination unit 205 includes a stop time determination unit 207. The stop time determination unit 207 calculates a stop correction amount by dividing the predetermined coefficient K1 by the angular acceleration R, and corrects the predetermined stop time t21 to a value obtained by adding the stop correction amount thereto. The stop correction amount increases as the load (angular acceleration R) of the first drive motor 53 increases. This is because the longer the load on the first drive motor 53, the longer it takes to stop the rotation after the drive of the first drive motor 53 is stopped.

The sheet conveyed by the first conveying roller 71 is conveyed to the timing roller 31 after the leading edge of the sheet is detected by the timing sensor 33. Since the timing roller 31 is not rotating at this time, the sheet is further curved by the first conveying roller 71 and the sheet is curved between the timing roller 31 and the first conveying roller 71. As a result, the inclination of the sheet is corrected by the timing roller 31. Here, the predetermined stop time t21 is a time from when the leading edge of the paper is detected by the timing sensor 33, and the paper with the smallest load is curved between the timing roller 31 and the first transport roller 71. The time required for this is a predetermined value.
Stop time t21 = t21 + K1 / R (1)

  The stop timing determination unit 205 determines the timing to stop the first drive motor 53 when the corrected stop time t21 has elapsed since the first detection signal was input from the first detection unit 121. When the corrected stop time t <b> 21 has elapsed since the first detection signal was input from the first detection unit 121, the drive control unit 203 turns off the first drive motor 53 and stops driving. As a result, the stop time t21 is corrected by the load of the first drive motor 53, so that the sheet can be bent by a predetermined amount between the first conveying roller 71 and the timing roller 31, and the inclination of the sheet can be changed. It can be corrected.

  The drive timing determination unit 209 determines the re-drive timing for driving the first drive motor 53 next after stopping the first drive motor 53 based on the angular acceleration R input from the load detection unit 201. The drive timing determination unit 209 includes a drive time determination unit 211. The drive time determination unit 211 calculates a drive correction amount by multiplying the predetermined coefficient K2 by the angular acceleration R, and corrects the predetermined drive time t31 to a value obtained by adding the drive correction amount thereto. The drive correction amount decreases as the load (angular acceleration R) of the first drive motor 53 increases. This is because the larger the load on the first drive motor 53, the longer the time from the start of the drive of the first drive motor 53 to the predetermined number of revolutions.

The sheet stopped between the timing roller 31 and the first conveying roller 71 is conveyed by the timing roller 31 when the timing roller 31 starts to rotate after a predetermined time has elapsed since the image writing signal was turned ON. The At this time, it is preferable to maintain a state where the sheet is curved by a predetermined amount between the timing roller 31 and the first transport roller 71. If the sheet is transported only by the timing roller 31 without driving the first transport roller 71, the sheet may be pulled by the first transport roller 71 and the tilt of the sheet may not be corrected. For this reason, it is preferable to rotate the first conveying roller 71 before the rotation of the timing roller 31. The predetermined drive time t31 is a time from when the image writing signal is turned ON, and is a time necessary for the sheet having the largest load to bend between the timing roller 31 and the first transport roller 71. It is a defined value.
Drive time t31 = t31 + K2 × R (2)

  The drive time t31 is based on the time when the image writing signal is turned ON, and is the elapsed time after the image writing signal is turned ON. The rotation of the timing roller 31 is started when the image writing signal is turned ON. Is the time when a predetermined time has elapsed since the image writing signal was turned ON. Therefore, the drive time determination unit 211 can determine the drive time t31 based on the timing at which the timing roller 31 starts to rotate.

  The stop timing determination unit 205 determines the timing for driving the first drive motor 53 when the corrected drive time t31 elapses after the image writing signal is turned ON. The drive control unit 203 turns on the first drive motor 53 and starts driving when the corrected drive time t31 has elapsed since the image writing signal was turned on. Since the driving time t31 is corrected by the load of the first drive motor 53, the sheet can be conveyed in a state where the sheet is curved by a predetermined amount between the first conveying roller 71 and the timing roller 31. The inclination can be corrected.

  Based on the angular acceleration input from the load detection unit 201, the determination unit 131 feeds paper among the main body paper feeding unit 20 and the first to fourth additional paper feeding units 50, 50 </ b> A, 50 </ b> B, and 50 </ b> C. It is determined whether the basis weight set for the selected item is correct. Specifically, the determination unit 131 acquires the sheet size and the remaining amount from the main body sheet feeding unit 20 and the first to fourth additional sheet feeding units 50, 50A, 50B, and 50C, and first to fourth additional sheet feeding. The basis weight set in advance for each of the paper sections 50, 50A, 50B, and 50C is acquired. Then, a reference table stored in advance in the storage unit 103 is read. The reference table is a table that defines the relationship between each of a plurality of combinations of paper size, remaining amount, and basis weight and the angular acceleration at the start of each of the first to fourth drive motors 53, 53A, 53B, and 53C. .

  FIG. 9 is a diagram illustrating an example of the reference table. FIG. 9 shows a reference table in the first drive motor 53 provided in the first additional paper feeder 50. Referring to FIG. 9, the reference table predetermines a relationship between a set of paper size, remaining amount, and basis weight and angular acceleration at the time of activation of first drive motor 53.

  Returning to FIG. 6, the acquired paper size, remaining amount, and basis weight of the first to fourth additional paper feeding units 50, 50 </ b> A, 50 </ b> B, and 50 </ b> C that are selected to feed paper. The angular acceleration determined by the reference table corresponding to the combination of quantities is acquired. The determination unit 131 determines whether the angular acceleration input from the load detection unit 201 is included in a predetermined range from the angular acceleration acquired from the reference table. If the angular acceleration is within the predetermined range, the basis weight is set. Is determined to be correct, but if it is not within the predetermined range, it is determined that the basis weight setting is incorrect. If the determination unit 131 determines that the basis weight setting is incorrect, the determination unit 131 outputs a notification instruction to the notification unit 133 and inputs the paper size and remaining amount acquired by the setting determination unit 135 and the load detection unit 201. Output angular acceleration.

  The notification unit 133 notifies the user that the basis weight setting is incorrect. For example, an error message is displayed on the display unit 113B.

  The setting determination unit 135 refers to the reference table stored in the storage unit 103, and the paper size and remaining amount associated with the angular acceleration that includes the angular acceleration input from the load detection unit 201 within a predetermined range. And all the basis weight pairs. Further, the size and remaining amount of the paper acquired from the selected one of the first to fourth additional paper feeding units 50, 50A, 50B, 50C selected to feed paper from the extracted set. Extract the pairs that contain it. At this stage, when a plurality of sets are extracted, one set that is associated with the angular acceleration closest to the angular acceleration input from the load detection unit 201 is determined. And the basic weight defined by the determined group is determined to be the basic weight for setting. The setting determining unit 135 outputs the determined basis weight to the setting changing unit 137.

  The setting changing unit 137 sets the basis weight set for the first to fourth additional paper feeding units 50, 50A, 50B, and 50C selected to feed paper, and the setting determining unit 135 Update with basis weight input from.

  The image forming control unit 125 controls the image forming unit 12 according to the image forming conditions determined by the updated basis weight to form an image. The image forming condition is, for example, a transfer voltage at the transfer roller 35 or a fixing temperature at the fixing roller 37. Although the transfer condition and the job change condition differ depending on the basis weight, the incorrect basis weight setting is updated to a correct value, so that transfer and fixing can be appropriately performed.

  Here, in the reference table, the load of the first drive motor 53 is associated with a set of paper size, paper remaining amount, paper basis weight, but the paper size, paper remaining amount, A set of at least one selected from the basis weight of the paper may be associated with the load of the first drive motor 53. For example, when the reference table associates any of the paper size, the remaining amount of paper, and the basis weight of the paper with the load, the size of the paper, the remaining amount of the paper, and the basis weight of the paper can be determined from the load.

  FIG. 10 is a flowchart illustrating an example of the flow of timing roller control processing. The timing roller control process is a process executed by the main CPU 101 when the main CPU 101 executes an image forming program. Referring to FIG. 10, main CPU 101 determines whether a print request has been accepted (step S01). For example, the communication I / F 109 or the network I / F 111 receives a print request by receiving print data from a computer. The process waits until a print request is accepted (NO in step S01). If a print request is accepted (YES in step S01), the process proceeds to step S02.

  In step S02, the number of printed sheets N is set in the variable n. The number N of prints is included in print data received from an external computer, and is obtained by extracting from the print data. In the next step S03, a paper feed tray is determined. A paper feed tray for storing paper of a size included in print data received from an external computer is determined from the main body paper feed unit 20 and the first to fourth additional paper feed units 50, 50A, 50B, and 50C. . The variable n in which the number N of prints is set in step S02 is passed to the CPU that controls the paper feed tray determined in step S03. Here, a case where the first additional paper feeding unit 50 is determined will be described. Therefore, the variable n is passed to the first CPU 81 included in the first additional paper feeding unit 50 and used in a paper feed control process executed by the first CPU 81 described later.

  In step S04, it is determined whether an image writing signal is detected. The image writing signal may be a signal that is a reference by the main CPU 101 and is a reference signal for controlling the image forming unit 12. For example, when the rotation of the transfer belt 17 reaches a predetermined position as a reference, a sensor for detecting the reference mark attached to the transfer belt 17 detects the image writing signal by detecting the reference mark. . The process waits until an image write signal is detected (NO in step S04). If an image write signal is detected (YES in step S04), the process proceeds to step S05.

  In step S05, timer 1 is started. The timer 1 measures the elapsed time after detecting the image writing signal. In the next step S06, it is determined whether or not the timing sensor 33 has been switched from OFF to ON. In other words, it is determined whether or not the leading edge of the paper has reached the position where the timing sensor 33 is installed. If the timing sensor 33 is switched on, the process proceeds to step S07; otherwise, the process proceeds to step S11. In step S11, it is determined whether or not the value of timer 1 has reached threshold value T1. If the value of timer 1 is the same as threshold value T1, the process returns to step S04; otherwise, the process returns to step S06. The threshold value T1 is the maximum value allowed from the detection of the image writing signal until the timing sensor 33 is turned on. After the threshold value T1 has elapsed since the detection of the image writing signal, If no image write signal is detected, the image cannot be formed.

  In step S07, it is determined whether or not the value of timer 1 has reached threshold value T2. The process waits until the value of timer 1 reaches threshold value T2 (NO in step S07). When the value of timer 1 reaches threshold value T2, the process proceeds to step S08. The threshold value T2 is a predetermined value as a time for starting the driving of the timing roller 31 after the image writing signal is detected. The predetermined value is set so that the position of the toner image formed on the transfer belt 17 and the sheet conveyed by the timing roller 31 coincide.

  In step S08, driving of the timing roller 31 is started. Thus, the sheet is conveyed by the timing roller 31 and conveyed to the transfer roller 35, and the toner image formed on the transfer belt 17 is transferred to the sheet. In step S09, it is determined whether or not the timing sensor 33 has been switched from ON to OFF. The process waits until the timing sensor 33 is switched off (NO in step S09). When the timing sensor 33 is switched off (YES in step S09), the process proceeds to step S10. In step S10, the driving of the timing roller 31 is stopped, and the process returns to step S04.

  FIG. 11 is a flowchart illustrating an example of the flow of paper feed control processing. The paper feed control process is a process executed by the first CPU 81 when the first CPU 81 executes a paper feed control program. The paper feed control program is a part of the image forming program. Referring to FIG. 11, first CPU 81 determines whether or not an image writing signal has been detected (step S21). An image write signal is input from the main CPU 101. The process waits until an image write signal is detected (NO in step S21). If an image write signal is detected (YES in step S21), the process proceeds to step S22.

  In step S22, driving of the first drive motor 53 is started. Thereby, the 1st conveyance roller 71 starts rotation. In the next step S23, the first clutch 64 is switched ON. Thereby, the rotation of the first drive motor 53 is transmitted to the first paper feed roller 63, and the first paper feed roller 63 starts to rotate. In step S24, timer 2 is started. The timer 2 measures the elapsed time after the first drive motor 53 starts driving. In the next step S25, stop drive time determination processing is executed. Although details of the stop drive time determination process will be described later, this is a process of determining the timing (stop time) for stopping driving of the first drive motor 53 and the timing (drive time) for restarting driving of the first drive motor 53. .

  In the next step S26, it is determined whether or not the first transport sensor 73 has been switched from OFF to ON. In other words, it is determined whether or not the leading edge of the sheet transported by the first paper feed roller 63 has reached the position where the first transport sensor 73 is installed. The process waits until the first transport sensor 73 is switched on (NO in step S26). If the first transport sensor 73 is switched on (YES in step S26), the process proceeds to step S27.

In the next step S27, the value of timer 2 is set to the constant t11. The constant t11 is set to the time from the start of driving the first drive motor 53 until the leading edge of the sheet reaches the position where the first conveyance sensor 73 is installed. In the next step S28, the constant t41 is changed to a value determined according to the following equation (1). The constant t41 is a value determined in advance as the time from when the first transport sensor 73 detects the trailing edge of the paper until the next rotation of the first paper feed roller 63 is started.
t41 = t41 + (tPS−t11) / 2 (1)

  When the second and subsequent sheets are taken out, the first drive motor 53 rotates at a predetermined number of revolutions, so there is little variation when the first clutch 64 is turned on. For this reason, the constant t11 corresponds to correction of deviation of the paper position in the first paper feed tray 61. Here, the correction amount is corrected to ½ of the deviation from the reference value tPS.

  In step S29, it is determined whether or not a predetermined time has elapsed since the first clutch 64 was switched on. The process waits until a predetermined time elapses after the first clutch 64 is turned on (NO in step S29). When a predetermined time elapses after the first clutch 64 is turned on (YES in step S29), the process is performed. Proceed to step S30. The predetermined time is a value determined in advance as a time sufficient for the first paper feed roller 63 to transport the paper to the first transport roller 71. In step S30, the first clutch 64 is switched from ON to OFF. As a result, the power transmitted from the first drive motor 53 to the first paper feed roller 63 is cut off. After this stage, the first paper feed roller 63 is driven by the paper conveyed by the first conveyance roller 71.

  In the next step S31, it is determined whether or not the timing sensor 33 has been switched from OFF to ON. The process waits until the timing sensor 33 is turned on (NO in step S31). If the timing sensor 33 is turned on (YES in step S31), the process proceeds to step S32. In step S32, the timer 2 is started. The timer 2 measures the elapsed time after the timing sensor 33 is switched on. In other words, the elapsed time after the leading edge of the sheet conveyed by the first conveying roller 71 reaches the position where the timing sensor 33 is installed is counted.

  In step S33, it is determined whether or not the value of timer 2 is equal to the stop time. The process waits until the value of timer 2 becomes equal to the stop time (NO in step S33), and when it becomes equal to the stop time (YES in step S33), the process proceeds to step S34. The stop time is the time determined in step S25. In step S34, the driving of the first drive motor 53 is stopped, and the process proceeds to step S35. By stopping the driving of the first drive motor 53, the first transport roller 71 does not receive power transmission from the first drive motor 53, but rotates to some extent due to inertia and stops. Since the stop time is set to a value that takes into account the amount of rotation due to the inertia, the sheet conveyed by the first conveying roller 71 is in a predetermined curved state between the first conveying roller 71 and the timing roller 31. And the inclination of the paper can be corrected.

  In the next step S35, it is determined whether or not the value of timer 1 has become equal to the drive time. The driving time is the time determined in step S25. The process waits until the value of timer 1 becomes equal to the drive time (NO in step S35), and if it becomes equal to the drive time (YES in step S35), the process proceeds to step S36.

  In step S36, driving of the first drive motor 53 is started, and the process proceeds to step S37. By driving the first drive motor 53, the first transport roller 71 starts to rotate. Since the drive time is set so that the timing at which the first conveying roller 71 starts rotating is slightly earlier than the timing at which the timing roller 31 starts rotating, the timing between the timing roller 31 and the first conveying roller 71 is set. A moderately curved state is maintained without the paper being pulled or bent too much. For this reason, the inclination of the paper can be corrected appropriately. Further, it is possible to reduce the excessive bending of the sheet and excessive contact with the conveyance path. Thereby, noise can be reduced.

  In step S37, it is determined whether or not the first transport sensor 73 has been switched from ON to OFF. The process waits until the first transport sensor 73 switches to OFF (NO in step S37). If switched (YES in step S37), the process proceeds to step S38. In step S38, the timer 3 is started. The timer 3 measures the elapsed time after the first transport sensor 73 is switched from ON to OFF. In step S39, the variable n is set to a value obtained by subtracting 1 from it, and the process proceeds to step S40. In step S40, it is determined whether or not the variable n is equal to “0”. If variable n is equal to “0”, the process proceeds to step S45; otherwise, the process proceeds to step S41.

  In step S41, it is determined whether or not the value of timer 3 that started timing in step S38 is equal to the constant t41 corrected in step S28. The process waits until the value of timer 3 becomes equal to constant t41 (NO in step S41). If the value of timer 3 is equal to constant t41, the process proceeds to step S42. In step S42, the first clutch 64 is switched from OFF to ON, and the process proceeds to step S43. As a result, the first paper feed roller 63 starts rotating, so that the next paper is started to be conveyed. In step S43, timer 2 is started and the process returns to step S26.

  On the other hand, when the process proceeds to step S44, the last sheet is supplied. In step S44, the driving of the first drive motor 53 is stopped, and the process ends.

  FIG. 12 is a flowchart illustrating an example of the flow of stop drive time determination processing. The stop drive time determination process is a process executed in step S25 of FIG. Referring to FIG. 12, the first CPU 81 detects angular acceleration (step S61). Angular acceleration is detected based on the rotation speed output by the first drive motor 53. In the next step S62, it is determined whether or not the rotational speed of the first drive motor 53 has reached a predetermined rotational speed. If the rotational speed of the first drive motor 53 has reached a predetermined rotational speed, the process is performed. If not, the process returns to step S61. An angular acceleration from when the first drive motor 53 starts to drive until reaching a predetermined rotational speed is detected. The angular acceleration may be at any timing as long as the first driving motor 53 starts driving and reaches a predetermined rotational speed, and the average angular acceleration detected during that time. May be used. Further, instead of detecting the angular acceleration, a time from when the first drive motor 53 starts to drive until reaching a predetermined rotational speed may be detected.

  In step S63, a stop correction amount is determined. Here, a value obtained by dividing the coefficient K1 by the angular acceleration is determined as the stop correction amount. In the next step S64, a drive correction amount is determined. Here, a value obtained by multiplying the coefficient K2 by the angular acceleration is determined as the drive correction amount. In the next step S65, the stop time is calculated. The stop time is a value obtained by adding the stop correction amount determined in step S63 to a predetermined stop reference time t21. In the next step S66, the drive time is calculated, and the process returns to the timing roller control process. The drive time is a value obtained by adding the drive correction amount determined in step S64 to a predetermined drive reference time t31.

  FIG. 13 is a flowchart illustrating an example of the flow of setting determination processing. The setting determination process is a process executed by the main CPU 101 when the main CPU 101 included in the printer 1 executes an image forming program. Referring to FIG. 13, the main CPU 101 detects the size of the paper that is the object of image formation (step S71). By acquiring the size included in the print data input from an external computer, the size of the paper that is the object of image formation is detected. In the next step S <b> 72, the remaining amount of paper stored in the paper supply tray (first additional paper supply unit 50) determined for paper supply is acquired from the first additional paper supply unit 50. In step S73, the basis weight of the paper stored in the paper supply tray (first extension paper supply unit 50) determined for paper supply is acquired. The basis weight of the paper stored in the first additional paper supply unit 50 is set in advance by the user inputting to the input unit 113A.

  In the next step S74, the reference table stored in advance in the storage unit 103 is read. The reference table is a table that defines the relationship between each of a plurality of combinations of paper size, remaining amount, and basis weight, and angular acceleration when the first drive motor 53 is activated. In the next step S75, angular acceleration is acquired. The startup angular acceleration detected thereby is acquired from the paper feed tray determined to feed the paper, here, the first additional paper feeder 50.

  Then, it is determined whether or not the acquired angular acceleration is included in a predetermined range from the angular acceleration predetermined by the reference table shown in FIG. If it falls within the predetermined range, the process ends. If not, the process proceeds to step S77. Here, the predetermined range is 15% above and below the angular acceleration determined by the reference table.

  In step S77, the user is notified that the basis weight setting is incorrect. Specifically, an error message is displayed on the display unit 113B. In the next step S78, a reference combination is extracted. Specifically, in the reference table read in step S74, a combination of paper size, remaining amount, and basis weight that includes the angular acceleration acquired in step S75 within a predetermined range is extracted. Here, since the paper size and the remaining amount are detected in step S71 and step S72, they extract the same combination. When a plurality of combinations of paper size, remaining amount, and basis weight that include the angular acceleration acquired in step S75 within a predetermined range are extracted, the combination having the closest angular acceleration among the extracted combinations is used as a reference. Extract as a combination. When the basis weight is extracted, the basis weight defined in the reference combination is determined, and the set basis weight is updated with the determined basis weight (step S79).

  The image forming unit 12 forms an image in accordance with image forming conditions determined by the updated basis weight. The image forming condition is, for example, a transfer voltage at the transfer roller 35 or a fixing temperature at the fixing roller 37. Although the transfer condition and the job change condition differ depending on the basis weight, the incorrect basis weight setting is updated to a correct value, so that transfer and fixing can be appropriately performed.

<Modification of load detection unit>
In the above-described embodiment, the load detection unit 201 detects the driving state of the first drive motor 53 based on the angular acceleration at the time of starting the first drive motor 53. By preparing in advance a correction table in which the relationship between the remaining amount and basis weight of the paper stored in the paper tray and the correction amount is set in advance, the angular acceleration when the first drive motor 53 is started up can be reduced. The correction amount can be determined without detection.

  FIG. 14 is a block diagram illustrating an outline of functions of the modified load detection unit. Referring to FIG. 14, the modified load detection unit 201 </ b> S includes a size acquisition unit 261, a remaining amount detection unit 263, a basis weight detection unit 265, and a correction amount determination unit 267. The size acquisition unit 261 acquires the size of the paper on which an image is to be formed and outputs it to the correction amount determination unit 267. Here, the size of the stored paper is detected from the output of the first size detection switch 66. The remaining amount detection unit 263 detects the remaining amount of paper stored in the first additional paper feeding unit 50 based on the output of the first paper remaining amount detection sensor 67 and outputs the detected amount to the correction amount determination unit 267. The basis weight detection unit 265 is input by the user to the input unit 113 </ b> A of the main body 10, detects the set basis weight from the main CPU 101 of the main body 10, and outputs the detected basis weight to the correction amount determination unit 267.

  Based on the size input from the size acquisition unit 161, the remaining amount input from the remaining amount detection unit 263, and the basis weight input from the basis weight detection unit 265, the correction amount determination unit 267 is stored in the storage unit 103. The stop correction amount and the drive correction amount are determined with reference to the stop correction amount table and the drive correction amount table stored in advance.

  FIG. 15 is a diagram illustrating an example of the stop correction amount table. Referring to FIG. 15, the stop correction amount table predetermines a relationship between a set of paper size, remaining amount and basis weight and a stop correction amount.

  FIG. 16 is a diagram illustrating an example of a drive correction amount table. Referring to FIG. 16, the stop correction amount table predetermines a relationship between a set of paper size, remaining amount and basis weight and a drive correction amount.

The stop time determination unit 207 and the drive time determination unit 211 determine the stop time and the drive time using the stop correction amount and the drive correction amount determined by the correction amount determination unit 267, respectively.
Stop time t21 = t21 + stop correction amount (1 ′)
Drive time t31 = t31 + drive correction amount (2 ′)

  Next, a case where an image is formed on the paper stored in the fourth additional paper supply unit 50C will be described. FIG. 17 is a block diagram illustrating an example of an outline of functions of the first to fourth CPUs and the main CPU when paper is fed from the fourth additional paper feeding unit. Compared to the block diagram shown in FIG. 6, the second CPU 81 </ b> A to fourth CPU 81 </ b> C are added, and the clutch control unit 213, the measurement unit 215, and the second detection unit 217 are deleted from the first CPU 81. In the second to fourth CPUs 81A, 81B, 81C, the same functions as the functions of the first CPU 81 shown in FIG. 6 are indicated by the same numbers with the symbols A, B, C added thereto.

  When an image is formed on the paper stored in the fourth additional paper supply unit 50C, the fourth paper supply roller 63C takes out the paper stored in the fourth additional paper supply unit 50C. Thereafter, the sheet is conveyed in the order of the fourth conveyance roller 71 </ b> C, the third conveyance roller 71 </ b> B, the second conveyance roller 71 </ b> A, and the first conveyance roller 71, and is conveyed to the timing roller 31.

  The load detection unit 201 included in the first CPU 81 detects an angular acceleration when the first drive motor 53 is activated when the first sheet is conveyed. The load detection unit 201A included in the second CPU 81A detects an angular acceleration when the first drive motor 53A is activated when the first sheet is conveyed. The load detection unit 201B included in the third CPU 81B detects angular acceleration when the third drive motor 53B is activated when the first sheet is conveyed. The load detection unit 201C included in the fourth CPU 81C detects angular acceleration when the fourth drive motor 53C is activated when the first sheet is conveyed. The angular acceleration detected when the fourth drive motor 53C is detected by the load detection unit 201C is the same as the angular acceleration detected by the load detection unit 201 when an image is formed on the paper stored in the first additional paper supply unit 50. is there.

  The timing at which the first to fourth transport rollers 71 and 71A to 71C are stopped and driven can be held in a curved manner by increasing the timing according to the lower stage (upstream) rather than simultaneously.

  As described above, the printer 1 as the image forming apparatus in the present embodiment includes the first to fourth additional paper feeding units 50, 50A, 50B, and 50C, and the first to fourth additional paper feeding units. Each of 50, 50A, 50B, and 50C includes first to fourth drive motors 53, 53A, 53B, and 53C, first to fourth feed rollers 63, 63A, 63B, and 63C that take out accumulated sheets, 1st-4th conveyance rollers 71, 71A, 71B, 71C and 1st-4th CPU81, 81A, 81B, 81C which controls them are provided. For example, a case where paper is fed from the first additional paper feeder 50 will be described as an example. The first CPU 81 detects the load of the first drive motor 53, and the drive control controls the first drive motor 53. The drive control unit 203 based on the detected load in order to stop the sheet conveyed by the first conveying roller 71 in a state where the sheet is curved between the timing roller 31 and the drive control unit 203. A stop timing determination unit 205 that determines a stop timing for stopping the first drive motor 53 is included. When the load of the first drive motor 53 varies depending on the type of paper transported by the first transport roller 71 and the load is different, the time from when the first drive motor 53 stops until the first transport roller 71 stops rotating. Is different. Since the stop timing for stopping the first drive motor 53 is determined based on the load of the first drive motor 53, it is possible to appropriately control the distance that the sheet is conveyed before the first conveyance roller stops rotating. .

  In addition, the image forming unit 12 that forms an image on a sheet, and is provided between the image forming unit 12 and the first conveying roller 71, and is driven by a drive source different from the first drive motor 53 to be image forming unit 12. A timing roller 31 (supplying means) for supplying paper to the printer, and a timing sensor 33 (first detection means) provided between the timing roller 31 and the first conveying roller 71 for detecting the presence or absence of paper. The stop timing determination unit 205 determines the time from when the sheet is detected by the timing sensor 33 to when the first drive motor 53 is stopped. If the load on the first drive motor 53 is different, the time from when the first drive motor 53 is stopped until the first conveying roller 71 stops is different, but the first drive motor after the timing sensor 33 detects the sheet. Since the time until the stop timing for stopping 53 is determined, the sheet can be stopped in a curved state between the timing roller 31 and the first conveying roller 71. As a result, even when the sheet conveyed by the first conveyance roller 71 is inclined with respect to the traveling direction, the inclination can be corrected by the timing roller 31.

  In addition, the drive control unit 203 further includes a drive timing determination unit 209 that determines a redrive timing for driving the first drive motor 53 next after stopping the first drive motor 53 based on the detected load. . When the load of the first drive motor 53 is different, the time from the state where the first conveying roller 71 is stopped to the predetermined rotational speed is different. Since the drive timing for re-driving the first drive motor 53 is determined based on the load of the first drive motor 53, it is possible to appropriately control the distance for transporting the sheet from the state where the first transport roller 71 is stopped. .

  Further, the drive timing determination unit 209 determines the time from the redrive timing to the timing at which the timing roller 31 starts conveying the sheet to the image forming unit 12. For this reason, the length of the sheet can be maintained at a predetermined length or more between the timing roller 31 and the first conveying roller 71, and the sheet is not pulled by the timing roller 31 and the first conveying roller 71. It can be avoided.

  The load detection unit 201 detects the number of rotations of the first drive motor 53, and based on the time from when the first drive motor 53 is driven until the predetermined number of rotations is reached, or the angular acceleration therebetween. Determine the load. The load on the first drive motor 53 can be detected more quickly and reliably.

  Further, the storage unit 103 stores a reference table that defines a reference load for each of a plurality of sets of paper size, paper remaining amount, and paper basis weight. Acquires the size of the stored paper, detects the remaining amount of paper stored in the paper feed tray 61, acquires the basis weight predetermined as the basis weight of the paper stored in the paper feed tray 61, and detects it The reference load defined by the reference table is acquired for the paper size, the remaining amount of paper and the basis weight of the paper, and the first drive determined by the load detection unit 201 within a predetermined range from the reference load A determination unit 131 that determines whether or not the load of the motor 53 is included is further provided. Since the load of the first drive motor 53 varies depending on the size of the sheet, the remaining amount of the sheet, and the basis weight of the sheet, a reference table is generated by measuring the reference load in advance and is detected by the load detection unit 201. If the load of the first drive motor 53 is not within a predetermined range from the reference load, it can be detected that the predetermined basis weight of the sheet is incorrect.

  In addition, when the main CPU 101 determines that the load of the driving unit detected by the load detecting unit is not included within a predetermined range from the reference load by the determining unit 131, the main CPU 101 notifies that the basis weight setting is incorrect. The notification part 133 to be further provided. By notifying the user, the user can be prompted to change the basis weight setting.

  The main CPU 101 is detected by the load detection unit 201 when the determination unit 131 determines that the load of the first drive motor 53 detected by the load detection unit 201 is not included within a predetermined range from the reference load. A setting determination unit 135 that determines a combination of the paper size, the paper basis weight, and the paper remaining amount related by the reference table based on the load. Based on the load detected by the load detection unit 201, the combination of the paper size, the paper basis weight, and the remaining paper amount related by the reference table is determined, so the correct value of the paper basis weight to be set. Can be determined.

  The main CPU 101 further includes a setting change unit 137 that changes a preset basis weight based on the basis weight of the paper determined by the combination determined by the setting determination unit 135, and the image forming unit 12 changes the setting. When the basis weight is changed by the unit 137, an image is formed under image forming conditions corresponding to the changed basis weight. For this reason, an image is formed under the image forming conditions corresponding to the basis weight of the actually stored paper, so that an image can be formed under the optimal image forming conditions on the paper.

  Further, the setting determination unit 135 detects the size of the paper stored in the paper feed tray, detects the remaining amount of paper stored in the paper feed tray, and detects the load detected by the load detection means, the reference When there are a plurality of combinations of the paper size, the basis weight of the paper, and the remaining amount of the paper related by the table, the load detection unit 201 selects the combination of the detected paper size and the remaining amount of the paper from the same combination. Determine the set associated with the load closest to the detected load.

  Further, the ROM 83 stores a reference table in which the relationship between the load of the first drive motor 53 and the size of the paper, the basis weight of the paper, and the remaining amount of the paper is determined in advance. A size acquisition unit 261 that acquires the size of the paper stored in the paper feed tray 61, a remaining amount detection unit 263 that detects the remaining amount of paper stored in the paper feed tray 61, and a paper that is stored in the paper feed tray 61. A basis weight detection unit 265 that acquires the basis weight of the paper, and determines the motor load by referring to the reference table with the detected paper size, paper remaining amount, and basis weight. The load of the first drive motor 53 varies depending on the size of the sheet, the remaining amount of the sheet, and the basis weight. By detecting them, the load of the first drive motor 53 is determined. The load can be easily detected.

  Further, the first additional paper feeder 50 further includes a first clutch 64 and a transport sensor 73 provided between the first paper feed roller 63 and the first transport roller 71. The first CPU 81 The clutch control unit 213 that controls the one clutch 64 and releases the first clutch 64 a predetermined time after the first clutch 64 is connected, and the time from when the first clutch 64 is connected to when the paper is detected by the conveyance sensor 73 And a clutch control unit 213 that connects the first clutch 64 after the sheet detected by the transport sensor 73 is no longer detected based on the measured time. Including a connection timing determination unit. The time from when the first clutch 64 is connected until the paper is conveyed between the first paper feed roller 63 and the first conveyance roller 71 is measured, and then the first clutch 64 is next based on the measured time. Is determined. For this reason, it is possible to correct the deviation of the paper stored in the first paper feed tray 61.

  Each of the first to fourth additional paper feeding units 50, 50A, 50B, and 50C includes first to fourth drive motors 53, 53A, 53B, and 53C and first to fourth paper feeding rollers 63, 63A, 63B, and 63C. And first to fourth transport rollers 71, 71A, 71B, 71C, and first to fourth CPUs 81, 81A, 81B, 81C. For example, the first CPU 81 includes a drive control unit 205, a load detection unit 201, and the like. , And the first to fourth additional paper feeding units 50, 50A, 50B, 50C are arranged to overlap each other, and the first to fourth additional paper feeding units 50, 50A, 50B, 50C are closest to the timing roller 31. The first additional paper feeder 50 includes a first additional paper feeder 50, a fourth additional paper feeder 50C for supplying paper, and second and third additional paper feeders 50A and 50B. The roller 71 is conveyed from upstream The sheet is conveyed to the timing roller 31, and the fourth conveyance roller 71C included in the fourth additional sheet feeding unit 50C is a third conveyance included in the third additional sheet feeding unit 50B. The third transport roller 71B transported to the roller 71B and possessed by the third additional paper feeder 50B transfers the paper transported from the fourth transport roller 71C to the second transport roller 71A possessed by the downstream second additional paper feeder 50A. The second conveyance roller 71A included in the second additional sheet feeding unit 50A conveys the sheet conveyed from the third conveyance roller 71B to the first conveyance roller 71 included in the downstream first additional sheet feeding unit 50, The load detection unit 201 included in each of the first to fourth additional paper feeding units 50, 50A, 50B, and 50C includes the first to fourth drives included in each of the first to fourth additional paper feeding units 50, 50A, 50B, and 50C. motor The stop timing determination unit 205 included in each of the first to fourth additional paper feeding units 50, 50A, 50B, and 50C detects the load for each of 3, 53A, 53B, and 53C. Stop timings for stopping the first to fourth drive motors 53, 53A, 53B, and 53C included in the units 50, 50A, 50B, and 50C are detected for the first to fourth drive motors 53, 53A, 53B, and 53C, respectively. Determine based on the load. In each of the first to fourth additional paper feeding units 50, 50A, 50B, and 50C, the paper can be stopped at an appropriate position.

  Further, the drive timing determination unit 209 included in each of the first to fourth additional paper feeding units 50, 50A, 50B, and 50C is the first included in each of the first to fourth additional paper feeding units 50, 50A, 50B, and 50C. The re-drive timing for re-driving the fourth drive motors 53, 53A, 53B, and 53C is determined based on the load detected for each of the first to fourth drive motors 53, 53A, 53B, and 53C. For this reason, in each of the plurality of additional paper feeding units, it is possible to appropriately control the distance for transporting the paper from the state where the transport unit is stopped.

  In the present embodiment, the first transport roller 71 is directly connected to the first drive motor 53, and the first clutch 64 is provided between the first paper feed roller 63 and the first drive motor 53. This is because the rotation control for the first paper feed roller 63 is more complicated than the rotation control for the first transport roller 71. That is, the rotation control for the first conveyance roller 71 may be control for starting or stopping conveyance in accordance with the preceding paper, whereas the rotation control for the first sheet feeding roller 63 is performed on the first sheet feeding tray 61. Since the variation in the position of the stored paper is large, the adjustment range of the timing for taking out the paper is large, and the control becomes complicated because it is necessary to secure a predetermined distance as the interval between the continuously conveyed paper. It is.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

<Appendix>
(1) The image forming apparatus according to (11), wherein the load detecting unit determines a load of the driving unit.
(2) Stop correction that predetermines a relationship between a set of paper size, paper basis weight, and remaining amount of paper and a stop correction amount for correcting a stop time that is predetermined to stop the driving unit Storage means for storing a quantity table,
The stop timing determination unit includes a stop time determination unit that refers to the stop correction amount table and determines a time from when a sheet is detected by the first detection unit to a stop timing to stop the driving unit. The image forming apparatus according to claim 11.
(3) an image forming unit that forms an image on the sheet conveyed by the conveying unit;
A supply unit that is provided between the image forming unit and the conveying unit and is driven by a driving source different from the driving unit to supply paper to the image forming unit;
A drive correction amount table in which the relationship between a set of paper size, paper basis weight, and remaining amount of paper and a drive correction amount for correcting a drive time that is predetermined for re-driving the drive means is determined. Storage means for storing
The drive control means refers to the drive correction amount table, and based on the detected load, determines the re-drive timing for driving the drive means next after stopping the drive means. The image forming apparatus according to claim 11, further comprising a unit.
(4) a first detection means provided between the supply means and the transport means for detecting the presence or absence of paper;
5. The image forming apparatus according to claim 4, wherein the stop timing determination unit includes a stop time determination unit that determines a time from when a sheet is detected by the first detection unit to when to stop the drive unit.
(5) The image forming apparatus according to (5), wherein the load detecting unit detects a start-up time from when the driving unit is driven to when a predetermined rotation speed is reached.
(6) The image according to claim 5, wherein the load detection unit detects an angular acceleration from when the driving unit is driven to a predetermined rotation number based on the detected rotation number. Forming equipment.
(7) The image forming apparatus according to (12), wherein the connection timing determination unit calculates a connection time from the detection of the sheet detected by the second detection unit to the connection timing.

1 is a schematic cross-sectional view illustrating a schematic configuration of a printer according to one embodiment of the present invention. It is a block diagram which shows an example of the outline of the hardware constitutions of a control board. It is a block diagram which shows the outline of the 1st extension control board which a 1st extension paper supply part has. It is a figure which shows an example of the change of the rotation speed at the time of starting of a 1st drive motor. It is a figure which shows an example of the change of the rotation speed at the time of the stop of a 1st drive motor. It is a block diagram which shows an example of each of the function which 1st CPU has, and the function which main CPU has. It is a timing chart for demonstrating the drive start and stop of a drive motor. It is a block diagram which shows the detailed function of a load detection part. It is a figure which shows an example of a reference | standard table. It is a flowchart which shows an example of the flow of a timing roller control process. 6 is a flowchart illustrating an example of a flow of paper feed control processing. It is a flowchart which shows an example of the flow of a stop drive time determination process. It is a flowchart which shows an example of the flow of a setting judgment process. It is a block diagram which shows the outline | summary of the function of the deform | transformed load detection part. It is a figure which shows an example of a stop correction amount table. It is a figure which shows an example of a drive correction amount table. It is a block diagram which shows an example of the outline | summary of the function of 1st-4th CPU and main CPU in the case of feeding a paper from a 4th additional paper supply part.

DESCRIPTION OF SYMBOLS 1 Printer, 10 Main body, 11 Control board, 12 Image formation part, 13 Drive roller, 15 Driven roller, 17 Transfer belt, 19A Image formation unit, 20 Main body paper feed part, 21 Main body paper feed tray, 22 Main body push-up board, 23 Main body paper feed roller, 25 Main body paper regulation plate, 27 Main body paper remaining amount detection sensor, 29 Main body empty sensor, 31 Timing roller, 33 Timing sensor, 35 Transfer roller, 37 Fixing roller, 50, 50A, 50B, 50C 4th additional paper feeder, 51, 51A, 51B, 51C 1st to 4th additional control board, 53, 53A, 53B, 53C 1st to 4th drive motor, 61, 63A, 63B, 63C 1st to 4th Feed tray, 62, 62A, 62B, 62C 1st to 4th push-up plate, 63, 63A, 63B, 63C 1st to 4th feed roller, 64, 64A, 64B, 64C 1st to 4th clutch, 65, 65A, 65B, 65C 1st to 4th sheet regulating plate, 66 1st size detection switch, 67, 67A, 67B, 67C 1st to 4th sheet remaining amount Detection sensor, 69, 69A, 69B, 69C 1st to 4th empty sensor, 71, 71A, 71B, 71C 1st to 4th transport roller, 73, 73A, 73B, 73C 1st to 4th transport sensor, 81, 81A, 81B, 81C 1st to 4th CPU, 83, 83A, 83B, 83C 1st to 4th ROM, 85, 85A, 85B, 85C 1st to 4th RAM, 101 main CPU, 103 storage unit, 105 card I / F , 105A memory card, 109 communication I / F, 110 bus, 111 network I / F, 113 operation panel, 113A input unit, 113B display unit 121 First detection unit, 123 Timing roller control unit, 125 Image formation control unit, 131 Judgment unit, 133 Notification unit, 135 Setting determination unit, 137 Setting change unit, 161 Size acquisition unit, 201, 201A, 201B, 201C, 201S Load detection unit, 203 drive control unit, 205 stop timing determination unit, 207 stop time determination unit, 209 drive timing determination unit, 211 drive time determination unit, 213 clutch control unit, 215 measurement unit, 217 second detection unit, 251 rotation Number detection unit, 253 driving state detection unit, 261 size acquisition unit, 263 remaining amount detection unit, 265 basis weight detection unit, 267 correction amount determination unit.

Claims (15)

Driving means;
A take-out means for taking out the accumulated paper;
A conveying unit that rotates with rotation of the driving unit and conveys a sheet conveyed by the take-out unit;
Drive control means for controlling the drive means;
Load detecting means for detecting the load of the driving means,
The drive control means; a stop timing determination means for determining a stop timing for stopping the drive means based on the detected load in order to stop the paper conveyed by the conveyance means at a predetermined position; An image forming apparatus. Image forming means for forming an image on the paper conveyed by the conveying means;
A supply unit that is provided between the image forming unit and the conveying unit and is driven by a driving source different from the driving unit to supply paper to the image forming unit;
A first detection means provided between the supply means and the transport means for detecting the presence or absence of paper;
2. The image forming apparatus according to claim 1, wherein the stop timing determination unit includes a stop time determination unit that determines a time from when a sheet is detected by the first detection unit to a stop timing to stop the driving unit.   The drive control means further includes drive timing determination means for determining a re-drive timing for driving the drive means next after stopping the drive means based on the detected load. The image forming apparatus described in 1. Image forming means for forming an image on the paper conveyed by the conveying means;
A supply unit that is provided between the image forming unit and the transport unit and is driven by a driving source different from the driving unit to supply paper to the image forming unit;
4. The image forming apparatus according to claim 3, wherein the drive timing determination unit includes a drive time determination unit that determines a time from the re-drive timing to a timing at which the supply unit starts conveyance to the image formation unit. The load detection means includes a rotation speed detection means for detecting the rotation speed of the drive means,
The image forming apparatus according to claim 1, wherein a load is determined based on a driving state of the driving unit from when the driving unit is driven until a predetermined number of rotations is reached. A clutch that is provided between the drive means and the take-out means, and that switches power transmission of the drive means;
When the take-out means takes out the first sheet, the drive control means connects the clutch at the same time or slightly more than the drive of the drive means,
The image forming apparatus according to claim 5, wherein the load detection unit determines a load based on a drive state of the drive unit from when the clutch is engaged until the drive unit reaches a predetermined rotation speed. Size acquisition means for acquiring the size of the paper stored in the paper feed tray;
A remaining amount detecting means for detecting the remaining amount of paper stored in the paper feed tray;
Grammage acquisition means for acquiring a grammage predetermined as the grammage of the paper stored in the paper feed tray,
Whether or not the load of the driving means detected by the load detecting means is included within a predetermined range from a predetermined reference load with respect to the detected paper size, remaining amount of paper and basis weight. The image forming apparatus according to claim 1, further comprising determination means for determining.   If the determination means determines that the load of the drive means detected by the load detection means is not included within a predetermined range from the reference load, a notification notifying that the basis weight setting is incorrect The image forming apparatus according to claim 7, further comprising means. A storage unit for storing a reference table in which a relationship between the load of the driving unit and the sheet size, the basis weight of the sheet, and the remaining amount of the sheet is determined in advance;
When it is determined by the determining means that the load of the driving means detected by the load detecting means is not included within a predetermined range from the reference load, based on the load detected by the load detecting means, The image forming apparatus according to claim 7, further comprising: a setting determining unit that determines a combination of a paper size, a paper basis weight, and a paper remaining amount related by the reference table. A setting change means for changing the preset basis weight with the basis weight of the paper determined by the combination determined by the setting determination means;
The image forming apparatus according to claim 9, wherein when the basis weight is changed by the setting change unit, the image forming unit forms an image under an image forming condition corresponding to the changed basis weight. Size detection means for detecting the size of the paper stored in the paper feed tray;
A remaining amount detecting means for detecting the remaining amount of paper stored in the paper feed tray,
The setting determination unit is configured to detect the detected sheet when there are a plurality of combinations of the load detected by the load detection unit and the sheet size, sheet basis weight, and sheet remaining amount related by the reference table. The image forming apparatus according to claim 10, wherein a group associated with a load closest to the load detected by the load detecting unit is determined from a plurality of combinations having the same size and the remaining amount of paper. The load detection means includes a size acquisition means for acquiring the size of the paper stored in the paper feed tray,
A remaining amount detecting means for detecting the remaining amount of paper stored in the paper feed tray;
A basis weight acquisition means for acquiring a basis weight predetermined as the basis weight of the paper stored in the paper feed tray;
Refer to a reference table that predetermines the relationship between the load of the driving means and the paper size, paper basis weight, and remaining paper amount based on the detected paper size, remaining paper amount, and paper basis weight. The image forming apparatus according to claim 1, wherein a load of the motor is determined. A clutch provided between the drive means and the take-out means, and for switching power transmission of the drive means;
A second detection means provided between the take-out means and the transport means for detecting the presence or absence of paper;
The drive control means releases the clutch after a predetermined time from connecting the clutch,
Measuring means for measuring the time from when the clutch is engaged until the second detection means detects the paper;
The connection timing determining means for determining the connection timing for connecting the clutch next after the paper detected by the second detecting means is no longer detected based on the measured time. The image forming apparatus according to any one of 12. A plurality of additional sheet feeding units each including the drive unit, the take-out unit, the transport unit, the drive control unit, and the load detection unit are arranged to overlap each other,
The plurality of additional paper feeding means includes a most downstream additional paper feeding means closest to the supply means, a most upstream additional paper feeding means for supplying paper, the most downstream additional paper feeding means, and the most upstream additional paper feeding means. And at least one intermediate additional sheet feeding means between
The transport means included in the most downstream additional paper feed means transports the paper transported from the upstream to the supply means,
The transport means included in the most upstream additional paper feed means transports the paper transported from the paper feed roller to the transport means included in the most upstream one of the at least one intermediate additional paper feed means,
The transport means included in each of the at least one intermediate additional paper feed means transports the paper transported from the upstream to the transport means included in the downstream intermediate additional paper feed means or the paper feed additional paper feed means,
Each of the plurality of load detecting means detects a load for each of the driving means included in each of the plurality of additional paper feeding means,
The stop timing determining means included in the plurality of drive control means determines a stop timing for stopping the drive means included in each of the plurality of additional paper feed means based on the detected load for the drive means. The image forming apparatus according to claim 1.   The drive timing determination means included in the drive control means determines a redrive timing for redriving the drive means included in each of the plurality of additional paper feed means based on the detected load for the drive means. The image forming apparatus according to claim 14.

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