JP2010120709A - Paper feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder capable of accurately placing the top surface position of a recording medium within a paper feed range determined by the upper limit position and lower limit position in a paper feedable range, and to provide an image forming device. <P>SOLUTION: The thickness of the fed recording medium is detected, and the accumulation value of the detected thickness of the recording medium is calculated. Based on the accumulation value of the fed recording medium, an amount of lifting-up is adjusted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet feeding device and an image forming apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copy or a printer includes a paper feeding device that feeds a recording medium for recording an image to an image forming unit.

  A recording medium loaded on a bottom plate that can be moved up and down by a wire or the like is stored in a tray of the paper feeding device.

  In such an apparatus, the uppermost recording medium in the tray is sequentially fed to the image forming unit, whereby the number of stacked recording media is reduced, and the position of the uppermost recording medium is supplied to the image forming unit. When it is below the lower limit position of the paper feedable range, the bottom plate is lifted up and adjusted so that the uppermost recording medium is within the paper feedable range.

As a technique for adjusting the amount of lift-up, for example, in Patent Document 1, the amount of lift-up is adjusted from the number of lift-ups, the interval between lift-ups, and the remaining amount of the recording medium stored in the tray. The method is described.
JP 2000-255797 A

  The present invention provides a sheet feeding device and an image forming apparatus capable of accurately placing the uppermost surface position of a recording medium within a sheet feeding range determined by an upper limit position of a sheet feeding possible range and a lower limit position of a sheet feeding possible range. For the purpose.

  In order to achieve the above object, the invention according to claim 1 is characterized in that lifting means for moving up and down a stacking section on which recording media are stacked, and an uppermost surface of the recording medium stacked on the stacking section are predetermined first. Position detecting means for detecting the position, paper feeding means for feeding the recording medium from the stacking unit, thickness detecting means for sensing the thickness of the recording medium fed by the paper feeding means, When the position detection means detects that the top surface of the recording medium is at the first position, the thickness detection means detects the top surface of the storage medium from the first position. And a control unit that controls the elevating unit so as to ascend to a second position that is higher by an amount determined based on a cumulative value of the thicknesses of the plurality of recording media.

  According to a second aspect of the present invention, there is provided an elevating means for elevating and lowering a stacking portion on which a recording medium is stacked, and a position for detecting that the uppermost surface of the recording medium moved up and down on the stacking portion is at a predetermined first position. Detected by the detecting means, the paper feeding means for feeding the recording medium from the stacking unit, the thickness detecting means for detecting the thickness of the recording medium fed by the paper feeding means, and the thickness detecting means A thickness cumulative value calculating means for calculating a cumulative value of the thickness of the recording medium, and the cumulative value calculated by the thickness cumulative value calculating means is such that the uppermost surface of the recording medium loaded on the stacking portion is a second position. Control means for controlling the elevating means so that the uppermost surface of the recording medium rises to a predetermined first position higher than the second position when a predetermined threshold value indicating that the recording medium is present In the paper feeder configured to include That.

  The invention of claim 3 further includes a plurality of sheet feeding units including the lifting unit and the sheet feeding unit, and a storage unit storing the threshold corresponding to the recording medium of each sheet feeding unit, The control means reads out a threshold value corresponding to the recording medium fed from any one of the plurality of paper feeding sections from the storage means, and uses the read threshold value as the predetermined threshold value. It is a feature.

  The invention according to claim 4 further includes a plurality of sheet feeding units including the elevating unit and the sheet feeding unit, and a storage unit in which the threshold corresponding to each of the sheet feeding units is stored. The means is characterized in that a threshold value corresponding to any one of the plurality of paper feeding units is read from the recording means, and the read threshold value is used as the predetermined threshold value.

  A fifth aspect of the invention includes the paper feeding device according to any one of the first to fourth aspects, and an image forming unit that forms an image on a recording medium fed by the paper feeding device. This is a sheet feeding device configured as described above.

  According to the first aspect of the present invention, the uppermost position of the recording medium can be accurately stored within the paper feed range determined by the upper limit position of the paper feedable range and the lower limit position of the paper feedable range.

  According to the second aspect of the present invention, the top surface position of the recording medium can be accurately stored within the paper feed range determined by the upper limit position of the paper feedable range and the lower limit position of the paper feedable range.

  According to the third aspect of the present invention, even when a plurality of types of recording media are stored, the lift-up amount can be appropriately adjusted according to the thickness of the recording medium.

  According to the fourth aspect of the present invention, even when a plurality of recording media having a plurality of thicknesses are stored in the plurality of sheet feeding units, the lift-up amount can be adjusted for each sheet feeding unit.

  According to the invention described in claim 5, it is possible to appropriately adjust the lift-up amount corresponding to the thickness of the recording medium.

Hereinafter, embodiments of the present invention will be described in detail.
(First embodiment)
As shown in FIG. 1, the image forming system 10 according to the first exemplary embodiment includes a paper feeding device 12 and an image forming device 16.

  The paper feeding device 12 feeds the recording medium 14 to the image forming device 16.

  The recording medium 14 may be paper, for example, but is not limited thereto, and may be a medium on which an image is formed by the image forming apparatus 16.

  The image forming apparatus 16 includes an image reading unit 18 and an image forming apparatus main body unit 20.

  The image reading unit 18 includes, for example, a line CCD sensor and a scanning mechanism that scans the line CCD sensor. The image reading unit 18 reads an image of a set original, for example, according to a user instruction.

  The image forming apparatus main body 20 includes an image forming unit 22 and forms an image on the recording medium 14 fed from the paper feeding device 12.

  The image forming unit 22 includes a photosensitive drum 24, a charger 26, an exposure device 28, a developing device 30, a transfer roll 32, and a fixing unit 34.

  Further, around the photosensitive drum 24, a charger 26, an exposure device 28, a developing device 30, and a transfer roll 32 are arranged.

  The photoconductor drum 24 is a cylindrical photoconductor and is driven to rotate at a predetermined rotation speed.

  The charger 26 uniformly charges the surface of the photosensitive drum 24.

  The exposure device 28 performs exposure according to image data of an image to be formed on the recording medium 14 to form an electrostatic latent image on the photosensitive drum 24. As the exposure device 28, for example, an LED print head in which a plurality of LEDs are arranged can be used. Further, a semiconductor laser, a collimator lens, a polygon mirror, an fθ lens, and the like may be provided, and the photosensitive drum 24 may be configured with an optical scanning device that performs scanning exposure according to image data.

  The developing device 30 develops the formed electrostatic latent image with toner.

  The transfer roll 32 transfers the toner image on the photosensitive drum 24 to the recording medium 14. The transferred toner image is fixed on the recording medium 14 by passing between a pressure roll 36 and a heating roll 38 provided in the fixing unit 34.

  Further, the recording medium 14 is discharged to a discharge tray 44 from a paper discharge port 42 provided on the side surface of the image forming apparatus 16 by a discharge roll 40.

  Next, the configuration of the sheet feeding device 12 will be described with reference to FIG.

  The sheet feeding device 12 includes a tray 46. In the tray 46, an elevating means for loading the recording medium 14, for example, a bottom plate 48 is provided.

  One end of the wire 50 is attached to the bottom plate 48 with the pulley 52 stretched. A drive gear 56 that is rotationally driven by a lift-up motor 54 is attached to the other end of the wire 50. As the drive gear 56 rotates in the direction of arrow A, the wire 50 wound around the pulley 52 is wound up, and the bottom plate 48 is raised. Further, when the drive gear 56 rotates in the direction of arrow B, the wire 50 wound around the pulley 52 is returned, and the bottom plate 48 is lowered.

  The paper feeding device 12 is provided with a paper feeding mechanism for feeding the recording medium 14. The sheet feeding mechanism includes a sheet feeding unit such as a sheet feeding roll 58, a sheet feeding roll rotating shaft 60, a sheet feeding roll support arm 62, a position detecting unit such as a feedable position detecting sensor 64, a feed roll 66, and a retard. A roll 68, a thickness detection sensor 70, a takeaway pinch roll 76, and a takeaway drive roll 78 are configured.

  The thickness detection means, for example, the thickness detection sensor 70 has a configuration in which a thickness detection actuator 74 is attached to a rotary encoder 72.

  When the recording medium 14 is in a range in which the recording medium 14 can be fed, the paper feeding device 12 moves the paper feeding roll 58 in a state where the uppermost surface of the recording medium 14 loaded on the bottom plate 48 is in contact with the paper feeding roll 58. By rotating in the direction of arrow C, the recording medium 14 is fed.

  A paper delivery roll support arm 62 that supports the vertical movement of the paper delivery roll 58 is attached to the paper delivery roll 58.

The paper delivery roll support arm 62 rotates about the paper delivery roll support arm rotation shaft 65. The paper carry-out roll support arm 62 is configured to rotate upward by a paper delivery roll solenoid 87 (not shown) when the solenoid is ON, and when the solenoid is OFF, it rotates downward by the elastic force of a spring (not shown). . As a result, the sheet delivery roll 58 moves up and down in the direction of arrow D.

  Further, a paper feedable position detection sensor 64 is disposed in the vicinity of the paper feed roll support arm 62. The feedable position detection sensor 64 is a sensor that detects the position of the uppermost surface of the recording medium 14 loaded on the bottom plate 48.

  The feedable position detection sensor 64 detects the uppermost surface of the recording medium 14 without being affected by the vertical movement of the paper feed roll 58.

  The fed recording medium 14 is fed into one sheet by a feed roll 66 and a retard roll 68 that is driven to rotate in the opposite direction to the feed roll 66 through a torque limiter (not shown).

  The recording medium 14 that has been rolled up is sent to the image forming apparatus 16 by a takeaway pinch roll (driven roll) 76 and a takeaway drive roll 78.

  Further, a thickness detection sensor 70 is disposed between the feed roll 66 and the takeaway pinch roll 76.

  The thickness detection sensor 70 is disposed at a position where the thickness detection actuator 74 rises every time the recording medium 14 is fed.

  When the recording medium 14 is fed and the thickness detecting actuator 74 is raised by the thickness of the recording medium 14, the rotary encoder 72 is rotated according to the amount of increase. The rotary encoder 72 outputs a signal corresponding to the rotation amount. That is, a signal corresponding to the thickness of the recording medium 14 is output.

  Next, with reference to FIG. 3, the main configuration of the electrical system of the sheet feeding device 12 will be described.

  As shown in the figure, the sheet feeder 12 includes a control unit 80 that is a control unit, a thickness detection sensor 70, a thickness cumulative value calculation unit 82 that is a thickness cumulative value calculation unit, a paper feedable position detection sensor 64, and a sheet. A feed roll motor 84, a feed roll motor 86, a retard roll motor 88, a takeaway drive roll motor 90, a lift-up motor 54, a paper feed roll solenoid 87, and an I / F (interface) 92 are included. Has been.

  Each time the recording medium 14 is fed, the thickness accumulated value calculation unit 82 receives the thickness value of the recording medium 14 detected by the thickness detection sensor 70, and accumulates (adds) the input thickness value. . Then, the calculated cumulative value is output to the control unit 80.

  The image forming apparatus 16 transmits an instruction signal for instructing the sheet feeding apparatus 12 to feed the recording medium 14 to the I / F 92. This instruction signal includes information such as the number of fed sheets. The I / F 92 outputs an instruction signal from the image forming apparatus 16 to the control unit 80.

  When the control unit 80 receives an instruction signal for feeding the recording medium 14 from the image forming apparatus 16 via the I / F 92, the control unit 80 controls the operation of the paper feed roll motor 84 and the like, and sends the recording medium 14 to the image forming apparatus 16. Feed paper.

  Next, a paper feed processing routine executed by the control unit 80 of the paper feed device 12 of the image forming system 10 according to the present embodiment will be described with reference to FIG.

  This routine is executed when the user operates the image forming apparatus 16 and selects an image forming service such as copying.

  First, in step 100, an initial operation processing routine as shown in FIG. In this initial operation processing routine, as shown in FIG. 5, first, in step 120, it is determined whether or not the feedable position detection sensor 64 is ON. The feedable position detection sensor 64 is turned on when the uppermost surface of the recording medium 14 is within the feedable range 94 shown in FIG.

  The feedable range 94 is, for example, a first position A, which is a lower limit position where the recording medium 14 can be fed, and an upper limit position where the recording medium 14 can be fed at a position higher than the first position A. And a predetermined second position B.

  Here, the lower limit position where the recording medium 14 can be fed is a position where the feeding is impossible when the uppermost surface of the recording medium 14 is below the position. Further, the upper limit position where the recording medium 14 can be fed is a position where feeding is impossible when the uppermost surface of the recording medium 14 is above this position. The first position A is not limited to the lower limit position, and may be within a range where the recording medium 14 can be fed.

  Further, the second position B is not limited to the upper limit position, and may be a position higher than the first position A within a range in which the recording medium can be fed. That is, the paper feedable range 94 is not limited to the range between the lower limit position and the upper limit position, and may be within a range where paper can be fed.

  Further, the sheet feedable position detection sensor 64 is turned OFF when the uppermost surface of the recording medium 14 is below the first position A. Therefore, if the sheet feedable position detection sensor 64 is ON, the current top surface position of the recording medium 14 is already within the sheet feedable range, so there is no need to lift up the bottom plate 48, as shown in FIG. Move on to step 102.

  On the other hand, if the determination in step 120 is negative, the process proceeds to step 122. In the current state, the position of the top surface of the recording medium 14 is not in the paper feedable range. That is, since the position of the uppermost surface of the recording medium 14 is lower than the first position A, the lift-up motor 54 is driven so that the feed-up position detection sensor 64 is lifted up until it is turned on. The bottom plate 48 is raised. As a result, the uppermost surface of the recording medium 14 rises to the first position A in the paper feedable range 94.

  Next, the routine proceeds to step 124 where the lift-up motor 54 is driven so as to further raise the bottom plate 48 by a predetermined threshold value. Here, the threshold value is a value corresponding to the paper feedable range 94 in FIG. That is, this corresponds to the cumulative thickness value when the recording medium 14 is fed up to the first position A located below the second position B, which is the upper limit position where paper can be fed. Therefore, the bottom plate 48 is raised so that the uppermost surface of the recording medium 14 rises to the second position B within the feedable range 94. As a result, the recording medium 14 rises to the second position B.

  Further, the process proceeds to step 126, and the control unit 80 outputs an instruction signal to the thickness cumulative value calculation unit 82 so as to reset the thickness cumulative value calculated by the thickness cumulative value calculation unit 82. Thereby, the thickness cumulative value calculation unit 82 resets the thickness cumulative value.

  By performing the initial operation processing routine described above, the position of the uppermost surface of the recording medium 14 falls within the feedable range.

  Next, paper is fed in step 102 shown in FIG. That is, the paper feed roll motor 84 and the like are controlled so that the recording medium 14 loaded on the bottom plate 48 is fed to the image forming apparatus 16.

  In step 104, it is determined whether or not the feedable position detection sensor 64 is OFF, that is, whether or not the uppermost surface of the recording medium 14 is below the first position A.

  If it is determined in step 104 that the sheet feedable position detection sensor 64 is not OFF, that is, if it is determined that the uppermost surface of the recording medium 14 is within the sheet feedable range 94, the process proceeds to step 110.

  When it is determined in step 104 that the feedable position detection sensor 64 is OFF, that is, by feeding paper, the position of the uppermost surface of the recording medium 14 is lower than the first position A and paper can be fed. If it is out of range, the process proceeds to step 106. In step 106, the calculated thickness cumulative value is fetched from the thickness cumulative value calculation unit 82.

  Next, in step 108, the lift-up motor 54 is driven so that the bottom plate 48 is lifted up by the accumulated thickness value input to the control unit 80. As a result, the uppermost surface of the recording medium 14 rises to the second position B.

  Then, the process proceeds to step 109, and the control unit 80 outputs an instruction signal to the thickness cumulative value calculation unit 82 so as to reset the thickness cumulative value calculated by the thickness cumulative value calculation unit 82. Thereby, the thickness cumulative value calculation unit 82 resets the thickness cumulative value.

  Next, the process proceeds to step 110, where it is determined whether or not the number of sheets fed by the instruction signal from the image forming apparatus 16 has been completed.

If it is determined in step 110 that the number of sheets has not been fed, the process returns to step 102 and the same operation as described above is repeated.
(Second Embodiment)
Next, a second embodiment will be described.

  In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The configurations of the image forming system 10, the paper feeding device 12, and the image forming device 16 are the same as those in the first embodiment, and a description thereof is omitted.

  Furthermore, the main configuration of the electrical system according to the second embodiment is also assumed to be the same as that of the first embodiment, and the description thereof is omitted.

  However, in the present embodiment, the feedable position detection sensor 64 detects that the position of the uppermost surface of the recording medium 14 has reached the first position A. That is, the feedable position detection sensor 64 is turned on when the recording medium 14 is at the first position A, and is turned off when the recording medium 14 is below the first position A.

  The first position A is not limited to the upper limit position where paper can be fed, and may be within the range where the recording medium 14 can be fed. Further, the second position B is not limited to the lower limit position where paper can be fed, and may be a position lower than the first position A within a range where the recording medium can be fed. That is, it may be within a range where paper can be fed as in the first embodiment.

  A sheet feed processing routine executed by the control unit 80 of the sheet feeder 12 of the image forming system 10 according to the present embodiment will be described with reference to FIG.

  As in the first embodiment, this routine is executed when the user operates the image forming apparatus 16 and selects an image forming service such as copying.

  First, at step 150, an initial operation processing routine as shown in FIG. 8 is performed. For example, when the image forming apparatus is first turned on, when the main power is turned off / on, or when the recording medium 14 is added to the tray 46, the accumulated thickness value may be forcibly reset. is there. In such a case, even if the uppermost surface of the recording medium 14 is not actually located at the position B, which is the upper limit of the feedable position, the accumulated thickness value is reset. It is determined whether or not the accumulated thickness value calculated by the accumulated thickness value calculation unit 82 is in a reset state.

  If a negative determination is made in step 200, that is, if the reset state is not set, the process proceeds to step 202. If an affirmative determination is made, that is, if the reset state is set, the process proceeds to step 204.

  In step 202, it is determined whether or not the accumulated thickness value calculated by the accumulated thickness value calculation unit 82 is equal to or greater than a predetermined threshold value.

  Here, the threshold value is a value corresponding to the paper feedable range 94 in FIG. That is, this corresponds to a cumulative thickness value when the recording medium 14 is fed up to the second position B located below the first position A, which is the upper limit position where paper can be fed.

  If an affirmative determination is made in step 202, the process proceeds to step 204.

  In step 204, the lift-up motor 54 is driven to raise the bottom plate 48 so that the sheet feedable position detection sensor 64 is lifted up until it is turned on. As a result, the position of the uppermost surface of the recording medium 14 rises to the first position A.

  In step 206, the control unit 80 outputs an instruction signal to the thickness cumulative value calculation unit 82 so as to reset the thickness cumulative value calculated by the thickness cumulative value calculation unit 82. Thereby, the thickness cumulative value calculation unit 82 resets the thickness cumulative value.

  On the other hand, if the determination in step 202 is negative, the current top surface position of the recording medium 14 is already within the feedable range, so there is no need to lift up the bottom plate 48, and the process proceeds to step 152 in FIG. To do.

  By performing the initial operation routine described above, the position of the uppermost surface of the recording medium 14 falls within the feedable range.

  Next, paper is fed in step 152 shown in FIG. That is, the paper feed roll motor 84 and the like are controlled so that the recording medium 14 loaded on the bottom plate 48 is fed to the image forming apparatus 16.

  In step 154, the calculated thickness cumulative value is fetched from the thickness cumulative value calculation unit 82.

  Next, in step 156, it is determined whether or not the accumulated thickness value acquired in step 154 is equal to or greater than a preset threshold value. That is, it is determined whether or not the position of the uppermost surface of the recording medium 14 is below the second position B.

  If it is determined in step 156 that the accumulated thickness value is not equal to or greater than the threshold value, that is, if the recording medium 14 is within the paper feedable range 94, the process proceeds to step 162.

  If it is determined in step 156 that the accumulated thickness value is equal to or greater than the threshold value, that is, by feeding paper, the position of the uppermost surface of the recording medium 14 is below the second position B and is out of the feedable range. If YES, go to step 158. In step 158, the lift-up motor 54 is driven so that the bottom plate 48 is lifted up until the sheet feedable position detection sensor 64 is turned on. As a result, the uppermost surface of the recording medium 14 rises to the first position A.

  Then, the process proceeds to step 160, and the control unit 80 outputs an instruction signal to the thickness cumulative value calculation unit 82 so as to reset the thickness cumulative value calculated by the thickness cumulative value calculation unit 82. Thereby, the thickness cumulative value calculation unit 82 resets the thickness cumulative value.

  Next, the process proceeds to step 162, where it is determined whether or not the number of sheets fed by the instruction signal from the image forming apparatus 16 has been completed.

  If it is determined in step 162 that the number of sheets has not been fed, the process returns to step 152 and the same operation as described above is repeated.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG.

  In the present embodiment, the same parts as those in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  The image forming system 10 </ b> A includes a paper feeding device 13, an image forming device 16, and an image reading unit 18.

  As illustrated in FIG. 10, the sheet feeding device 13 includes a plurality of (in this embodiment, three as an example) sheet feeding units 13 </ b> A to 13 </ b> C.

  The paper feeding device 13 is provided in the image forming apparatus main body 20.

  The paper feeding units 13A to 13C have the same configuration as that of the paper feeding device 12 in FIG. 2, and “A” to “C” are added to the end of the reference numerals of the same components.

  The image forming apparatus 16 and the image reading unit 18 are the same as those described in the first embodiment of FIG.

  The paper feeding units 13A to 13C feed the recording media 14A to 14C to the image forming unit 22, respectively.

  The recording media 14A to 14C are stacked on the respective trays 46A to 46C of the paper feeding units 13A to 13C.

  The recording media 14A to 14C can be, for example, types of recording media having different thicknesses.

  In the following description, when not limited to any one of the paper feeding units 13A to 13C, it will be simply referred to as “paper feeding unit 13”, and similarly, not limited to any one of the recording media 14A to 14C. In the following description, it is simply referred to as “recording medium 14”.

  Next, with reference to FIG. 11, an essential configuration of the electric system of the paper feeding unit 13 will be described.

  In addition, the same code | symbol is attached | subjected to the part similar to the principal part structure which concerns on 1st Embodiment, and description is abbreviate | omitted.

  In the third embodiment, the feedable position detection sensors 64A to 64C, the thickness detection sensors 70A to 70C, the thickness cumulative value calculation units 82A to 82C, and the lift-up motor 54A corresponding to the paper feed units 13A to 13C, respectively. To 54C, paper feed motors 84A to 84C, feed roll motors 86A to 86C, retard roll motors 88A to 88C, takeaway drive motors 90A to 90C, and paper feed roll solenoids 87A to 87C.

  In the third embodiment, a storage unit 81 serving as a storage unit is provided.

  The storage unit 81 stores a predetermined threshold value for each of the recording media 14A to 14B stacked on the paper feeding units 13A to 13B.

  Next, a paper feed processing routine executed by the control unit 80 of the image forming apparatus 10A according to the present embodiment will be described with reference to FIG.

  This routine is also executed when the user operates the image forming apparatus 16 to select an image forming service such as copying.

  First, in step 250, a threshold value corresponding to the recording medium 14 designated by the selected image forming service is read from the threshold values stored in the storage unit 81.

  In steps 252 to 256, the same processing as that in steps 150 to 156 in the second embodiment is performed on the sheet feeding unit 13 on which the designated recording medium 14 is stacked.

  However, in step 258, the accumulated thickness value of the sheet feeding unit 13 corresponding to the designated recording media 14A to 14C is read from any of the accumulated thickness value calculating units 82A to 82C.

  In Step 260 to Step 264, the same processing as that in Step 158 to Step 162 in the second embodiment is performed on the paper feeding unit 13 on which the designated recording medium 14 is stacked.

  Further, another embodiment of the third embodiment will be described with reference to FIG. 14 regarding a paper feed processing routine executed by the control unit 80 of the image forming apparatus 10A according to the present embodiment.

  In step 250, the predetermined threshold values are read out from the respective paper feeding units 13A to 13C stored in the recording unit 81. In steps 252 to 256, the same processing as that in steps 150 to 156 in the second embodiment is performed on the sheet feeding unit 13 on which the designated recording medium 14 is stacked. However, in step 258, the thickness cumulative value corresponding to the designated paper feed units 13A to 13C is read from any of the thickness cumulative value calculation units 82A to 82C. In Step 260 to Step 264, the same processing as Step 158 to Step 162 in the second embodiment is performed on the paper feeding unit 13 on which the designated recording medium 14 is stacked.

  In the first to third embodiments, the case where the thickness detection sensor 70 includes the rotary encoder 72 and the thickness detection actuator 74 has been described. However, the present invention is not limited to this, and for example, FIG. As shown in FIG. 4, the laser displacement meter 96 and the roller 98 may be used. In this case, the thickness of the fed recording medium 14 is detected by measuring the amount of vertical movement of the roller 98 with the laser displacement meter 96. In the first to third embodiments, the sensor for detecting the position of the uppermost surface of the recording medium 14 loaded on the bottom plate 48 is not affected by the vertical movement of the paper feed roll 58. Is provided so as to detect the position of the uppermost surface of the recording medium. However, a feedable position detection sensor is provided so as to detect the vertical movement position of the paper feed roll support arm 62, and the paper feed roll 58 is provided with the bottom plate 48. The position of the uppermost surface of the recording medium 14 loaded on the bottom plate 48 is detected by detecting the position of the paper feed roll support arm 62 in a state in contact with the uppermost surface of the recording medium 14 loaded thereon. Such a configuration is also applicable to the present invention.

  Note that the configurations of the paper feeding device, the image forming system, and the image forming device according to each of the above embodiments are merely examples, and it is needless to say that the configurations can be appropriately changed without departing from the gist of the present invention.

  Further, the image forming unit 22 in the image forming apparatus 16 of the present invention has been described in the case of the electrophotographic method, but other methods such as an ink jet recording method may be used.

  In addition, the flow of the processing program described in each of the above-described embodiments is also an example, and within a range that does not depart from the gist of the present invention, the processing order of each step is changed, unnecessary steps are deleted, new steps are added, etc. It goes without saying that you can do that.

1 is a schematic diagram illustrating a configuration of an image forming system according to a first embodiment. It is the schematic which shows the structure of the paper feeder which concerns on 1st Embodiment. 1 is a block diagram illustrating a configuration of an image forming system according to a first embodiment. 4 is a flowchart illustrating a flow of paper feed processing according to the first embodiment. 6 is a flowchart illustrating a flow of processing of an initial operation of the sheet feeding device according to the first embodiment. It is the schematic which shows the paper feeding operation | movement which concerns on 1st Embodiment. 10 is a flowchart showing a flow of paper feed processing according to the second embodiment. 10 is a flowchart illustrating a flow of processing of an initial operation of the sheet feeding device according to the second embodiment. It is the schematic which shows the paper feeding operation | movement which concerns on 2nd Embodiment. It is the schematic which shows the structure of the image forming apparatus which concerns on 3rd Embodiment. It is a block diagram which shows the structure of the image forming system which concerns on 3rd Embodiment. 10 is a flowchart illustrating a flow of a paper feed process according to a third embodiment. It is the schematic which shows the structure of the paper feeder which concerns on a modification. 10 is a flowchart illustrating a flow of a sheet feeding device according to a modification of the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming system 12 Paper feeder 14 Recording medium 22 Image forming part 46 Tray 48 Bottom plate (lifting means)
50 Wire 52 Pulley 54 Lift-up motor 56 Drive gear 58 Paper feed roll (paper feeding means)
64 Feedable position detection sensor (position detection means)
66 Feed roll 68 retard roll 70 Thickness detection sensor (thickness detection means)
76 Takeaway pinch roll 78 Takeaway drive roll 80 Control unit (control means)
81 Storage section (storage means)
82 Thickness cumulative value calculation unit (thickness cumulative value calculation means)
94 Feedable range 95 Threshold 96 Laser displacement meter 98 Roller

Claims (5)

Elevating means for elevating and lowering the stacking section on which the recording medium is loaded;
Position detecting means for detecting that the uppermost surface of the recording medium loaded on the loading section is in a first position determined in advance;
Paper feeding means for feeding the recording medium from the stacking unit;
Thickness detecting means for detecting the thickness of the recording medium fed by the paper feeding means;
When the position detection means detects that the top surface of the recording medium is at the first position, the thickness detection means detects the top surface of the storage medium from the first position. Control means for controlling the elevating means to ascend to a second position that is higher by an amount determined based on a cumulative value of thicknesses of the plurality of recording media;
A paper feeder equipped with. Elevating means for elevating and lowering the stacking section on which the recording medium is loaded;
Position detecting means for detecting that the uppermost surface of the recording medium moved up and down by the stacking portion is in a first position determined in advance;
Paper feeding means for feeding the recording medium from the stacking unit;
Thickness detecting means for detecting the thickness of the recording medium fed by the paper feeding means;
A thickness cumulative value calculating means for calculating a cumulative value of the thickness of the recording medium detected by the thickness detecting means;
When the cumulative value calculated by the cumulative thickness value calculation means becomes a predetermined threshold value indicating that the uppermost surface of the recording medium stacked on the stacking unit is at the second position, the recording medium Control means for controlling the elevating means so that the uppermost surface of the elevating part rises to a predetermined first position higher than the second position;
A paper feeder equipped with. A plurality of paper feed units including the lifting means and the paper feed means;
Storage means for storing the threshold value corresponding to the recording medium of each paper feed unit,
The control unit reads a threshold value corresponding to the recording medium fed from any one of the plurality of paper feeding units from the storage unit, and uses the read threshold value as the predetermined threshold value. The sheet feeding device according to claim 2. A plurality of paper feed units including the lifting means and the paper feed means;
Storage means for storing the threshold value corresponding to each of the paper feeding units,
The sheet feeding device according to claim 2, wherein the control unit reads a threshold value corresponding to any one of the plurality of sheet feeding units from the recording unit, and uses the read threshold value as the predetermined threshold value. A sheet feeding device according to any one of claims 1 to 4,
Image forming means for forming an image on a recording medium fed by the paper feeding device;
An image forming apparatus.

Images