JP2013069716A - Solenoid control device, paper transport device equipped with solenoid control device, and image formation device equipped with paper transport device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce collision noise of a plunger.SOLUTION: At the time of suction of a plunger 85, while a current pulse PI is being supplied to a coil 96, width d of the current pulse PI is widened from 2 ms to 9 ms in increment of 1 ms at 9 steps. Further, the current pulse PI whose width d is 2 ms is supplied five times, and every time the width d of the current pulse PI is widened stepwise, the number of current pulses PI is decreased, so that the current pulses PI of width d being 6 ms, 7 ms, 8 ms, and 9 ms are each supplied once. At the time of protrusion of the plunger 85, electrification to the coil 96 is cut off only for a predetermined period T, and then while the current pulse PI of current value i is being supplied to the coil 96, the width d of the current pulses PI is narrowed from 7 ms to 2 ms in increment of 1 ms at six steps, and further the current pulses PI whose widths d are 7 ms, 6 ms, 5 ms, 4 ms, and 3 ms are each supplied once, thus the current pulse PI whose width d is 2 ms is supplied twenty times.

Description

  The present invention relates to a solenoid control device that controls a solenoid that attracts or protrudes a plunger by a magnetic force of a coil, a paper transport device including the solenoid control device, and an image forming apparatus including the paper transport device.

  As is well known, a solenoid moves a plunger in one direction by a spring or the like and moves the plunger in the opposite direction against the biasing force of a spring or the like by the magnetic force of a coil. A stopper that restricts the movement of the jar is often provided. However, when the plunger is moved by simply turning the coil energization on and off, when the coil magnetic force overcomes the urging force of a spring or the like, or when the coil energization is turned off, the plunger speed rapidly increases. Because the plunger collided with the stopper, the collision sound was loud.

  For this reason, although a cushioning material such as a rubber member may be provided between the plunger and the stopper, the collision noise cannot be effectively reduced.

  On the other hand, the energization current of the coil may be subjected to pulse width modulation (PWM). For example, in Patent Document 1, a pulse supplied to a coil is subjected to pulse width modulation (PWM), an inflection point of a current flowing through the coil is detected, and the pulse is turned on / off based on the current value of the inflection point. The ratio is changed to reduce power consumption.

JP 2001-74066 A

  As described above, conventionally, a cushioning material such as a rubber member is provided between the plunger and the stopper. However, the collision sound of the plunger cannot be effectively reduced.

  In Patent Document 1, the on / off ratio of the pulse supplied to the coil is changed to reduce power consumption, but the change of the on / off ratio of the pulse does not reduce the collision sound of the plunger. There is no disclosure or suggestion of such technical ideas.

  Accordingly, the present invention has been made in view of the above-described conventional problems, and includes a solenoid control device capable of effectively reducing the collision sound of the plunger, a paper transport device including the solenoid control device, and the An object of the present invention is to provide an image forming apparatus provided with a sheet conveying device.

  In order to solve the above problems, a solenoid control device of the present invention is a solenoid control device that controls a solenoid that attracts a plunger by the magnetic force of a coil, and is supplied to the coil when the plunger is attracted. And a control unit that sequentially increases the magnetic force of the coil, and the plunger receives a biasing force in a protruding direction during the suction process, and the magnetic force of the coil It is sucked against the urging force.

  In this way, when the plunger is attracted by the magnetic force of the coil, if the width of the pulse supplied to the coil is increased stepwise and the magnetic force of the coil is increased sequentially, the plunger will resist the biasing force in the protruding direction. Then, it can be gradually moved and sucked, and while the plunger is sucked, the impact of the plunger with respect to the stopper can be relaxed and the collision sound can be reduced.

  Further, in the solenoid control device of the present invention, the control unit increases the number of pulses having a width set at the time of disclosing supply of the pulse to the coil, and when the width of the pulse is increased stepwise, The number of pulses is made smaller than the number of pulses having a width one stage before.

  Thus, by adjusting not only the pulse width but also the number of pulses, the speed of the plunger can be controlled more effectively.

  Furthermore, in the solenoid control apparatus of the present invention, the control unit continuously turns on the coil after the width of the pulse is maximized.

  Thereby, the suction state of the plunger can be stably maintained.

  In the solenoid control device of the present invention, the control unit maintains the off period between the pulses shorter and constant than the width of the pulses.

  Thereby, a plunger can be controlled stably.

  Furthermore, in the solenoid control device of the present invention, the control unit gradually increases the magnetic force of the coil by increasing the width of the pulse in three steps or more.

  Thus, when the width of the pulse is increased in three steps or more, the speed of the plunger can be controlled more effectively.

  Next, the solenoid control device of the present invention is a solenoid that controls the solenoid that attracts the plunger by the magnetic force of the coil, causes the plunger to protrude by the urging force of the urging member, and limits the protruding amount of the plunger by the stopper. The control device is configured to turn off the energization of the coil for a certain period in a state in which the plunger is sucked by continuously turning on the energization of the coil, and then the pulse supplied to the coil A control unit is provided for reducing the magnetic force of the coil sequentially by narrowing the width stepwise.

  In this way, when the energization to the coil is continuously turned on and the plunger is attracted, if the energization to the coil is turned off for a certain period, the movement of the plunger by the urging force of the urging member is started. When the pulse width supplied to the coil is reduced stepwise and the magnetic force of the coil is sequentially reduced, the plunger can be braked to reduce the plunger speed. The impact of the plunger can be alleviated and the impact sound can be reduced.

  In the solenoid control device of the present invention, when the width of the pulse is reduced stepwise, the control unit increases the number of pulses more than the number of pulses having a width one step before.

  Thus, by adjusting not only the pulse width but also the number of pulses, the speed of the plunger can be controlled more effectively.

  Furthermore, in the solenoid control device of the present invention, the control unit turns off the energization to the coil after the width of the pulse is made the smallest.

  Thereby, the protrusion state of a plunger can be maintained stably.

  In the solenoid control device of the present invention, the control unit maintains the off period between the pulses shorter and constant than the width of the pulses.

  Thereby, a plunger can be controlled stably.

  Furthermore, in the solenoid control device of the present invention, the control unit reduces the magnetic force of the coil sequentially by narrowing the pulse width in three steps or more.

  Thus, when the pulse width is narrowed in three steps or more, the speed of the plunger can be controlled more effectively.

  On the other hand, the paper transport device of the present invention includes a drive roller and a driven roller that is set to switch between a pressure contact state and a separation state with respect to the drive roller, and a sheet is fed between the drive roller and the driven roller that are in pressure contact with each other. A sheet conveying device that sandwiches and conveys the solenoid control device of the present invention and a movement of a plunger of the solenoid control device to the driven roller, moves the driven roller, and moves the driven roller relative to the driving roller. And a link mechanism that switches between a pressed state and a separated state of the driven roller.

  In such a sheet conveying apparatus of the present invention, it is possible to reduce the collision noise of the plunger when the driven roller is pressed against and separated from the driving roller.

  An image forming apparatus of the present invention includes the above-described paper transport device of the present invention, and transports a document or recording paper by the paper transport device.

  Such an image forming apparatus of the present invention also has the same operational effects as the paper conveying apparatus of the present invention.

  In the present invention as described above, when the plunger is protruded and attracted, the pulse width supplied to the coil is changed stepwise, and the magnetic force of the coil is sequentially changed. Or the speed of the plunger can be reduced, the impact of the plunger against the stopper can be reduced, and the impact sound can be reduced.

1 is a cross-sectional view illustrating an image forming apparatus including a sheet conveying device to which an embodiment of a solenoid control device of the present invention is applied. FIG. 2 is an enlarged cross-sectional view illustrating an image reading device and a sheet conveying device in the image forming apparatus of FIG. 1. FIG. 3 is a plan view showing the internal structure of the paper transport device as viewed from above. FIG. 3 is a perspective view showing the internal structure of the paper transport device as viewed obliquely from above. FIG. 5 is a side view showing a mechanism for contacting and separating each reversing roller in the paper transport device. FIG. 6 is a perspective view illustrating a mechanism for contacting and separating each reversing roller in the paper transport device. FIG. 4 is a cross-sectional view illustrating a configuration of a solenoid in the paper transport device. FIG. 6 is a side view illustrating a state where each reversing roller is in contact with the sheet conveying device. FIG. 3 is a side view schematically illustrating a sheet transport device. FIG. 3 is a block diagram illustrating a control system such as a solenoid in the paper transport apparatus. (A) is a waveform diagram showing a current pulse supplied to the coil when the solenoid plunger is attracted, and (b) organizes the width of the current pulse, the number of current pulses, and the off period between the current pulses. It is a chart shown. It is a side view which shows typically a main part of a solenoid, a coil, a plunger, E ring, a stopper, each torsion coil spring, etc., (a) shows the state where the plunger protruded, and (b) is the half suction of the plunger. Or the state which protruded is shown, (c) has shown the state by which the plunger was attracted | sucked. (A) is a waveform diagram showing a current pulse supplied to the coil when the solenoid plunger is protruded, and (b) arranges the width of the current pulse, the number of current pulses, and the off period between the current pulses. It is a chart shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view illustrating an image forming apparatus including a sheet conveying device to which an embodiment of a solenoid control device of the present invention is applied. The image forming apparatus 1 is a so-called multi-function machine having a scanner function, a copying function, a printer function, a facsimile function, and the like, and transmits an image of a document read by the image reading device 41 to the outside or reads the image. An original image or an externally received image is recorded or formed on a recording sheet in color or single color.

  The image forming apparatus 1 includes an optical scanning device 11, a developing device 12, a photosensitive drum 13, a drum cleaning device 14, a charger 15, an intermediate transfer belt device 16, a fixing device 17, and a paper for printing an image on a recording paper. A transport path S, a paper feed tray 18, a paper discharge tray 19, and the like are provided.

  The image data handled in the image forming apparatus 1 uses data corresponding to a color image using each color of black (K), cyan (C), magenta (M), yellow (Y), or a single color (for example, black). This is in accordance with the monochrome image. For this reason, four each of the developing device 12, the photosensitive drum 13, the drum cleaning device 14, and the charger 15 are provided so as to form four types of toner images corresponding to the respective colors, and black, cyan, Four image stations Pa, Pb, Pc, and Pd are configured in association with magenta and yellow.

  Each photoconductor drum 13 has a photosensitive layer on the surface thereof. Each charger 15 is a charging means for uniformly charging the surface of each photosensitive drum 13 to a predetermined potential. In addition to a contact-type roller-type or brush-type charger, a charger-type charger. Is used.

  The optical scanning device 11 is a laser scanning unit (LSU) provided with a laser diode and a reflection mirror, and exposes the surface of each charged photosensitive drum 13 according to image data and corresponds to the image data on those surfaces. An electrostatic latent image is formed.

  Each developing device 12 develops the electrostatic latent image on the surface of each photoconductive drum 13 with each color toner, and forms each color toner image on the surface of each photoconductive drum 13. Each drum cleaning device 14 removes and collects toner remaining on the surface of each photosensitive drum 13 after development and image transfer.

  The intermediate transfer belt device 16 is disposed above each photosensitive drum 13 and includes an intermediate transfer belt 21, an intermediate transfer belt driving roller 22, a driven roller 23, four intermediate transfer rollers 24, and a belt cleaning device 25. ing.

  The intermediate transfer belt 21 is formed by forming a film having a thickness of about 100 μm to 150 μm into an endless belt shape. The intermediate transfer belt drive roller 22, the driven roller 23, each intermediate transfer roller 24, and the like stretch and support the intermediate transfer belt 21, and move the intermediate transfer belt 21 in the arrow direction C.

  Each intermediate transfer roller 24 is rotatably supported in the vicinity of the intermediate transfer belt 21 and is pressed against the respective photosensitive drums 13 via the intermediate transfer belt 21.

  Each color toner image on the surface of each photoconductor drum 13 is sequentially transferred to the intermediate transfer belt 21 and a color toner image is formed on the intermediate transfer belt 21. Transfer of the toner image from each photosensitive drum 13 to the intermediate transfer belt 21 is performed by each intermediate transfer roller 24 that is in pressure contact with the back surface of the intermediate transfer belt 21. Each intermediate transfer roller 24 is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). Each intermediate transfer roller 24 is applied with a high-voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) in order to transfer the toner image. A high voltage is uniformly applied to the recording paper by the material.

  In this way, the toner images of the respective colors on the surfaces of the respective photosensitive drums 13 are stacked on the intermediate transfer belt 21 to become a color toner image indicated by the image data. This color toner image is conveyed together with the intermediate transfer belt 21 and transferred onto a recording sheet in a nip region between the intermediate transfer belt 21 and the transfer roller 26a of the secondary transfer device 26.

  The transfer roller 26a of the secondary transfer device 26 has a voltage (a high voltage having a polarity (+) opposite to the toner charging polarity (-)) for transferring the toner image of each color on the intermediate transfer belt 21 onto a recording sheet. Is applied. Further, in order to constantly obtain a nip region between the intermediate transfer belt 21 and the transfer roller 26a of the secondary transfer device 26, either the transfer roller 26a or the intermediate transfer belt drive roller 22 is made of a hard material (metal or the like). The other is made of a soft material such as an elastic roller (such as an elastic rubber roller or a foaming resin roller).

  Further, the toner image on the intermediate transfer belt 21 may not be completely transferred to the recording paper by the secondary transfer device 26, and the toner may remain on the intermediate transfer belt 21, and this residual toner may be mixed with toner in the next step. It will cause to generate. For this reason, the residual toner is removed and collected by the belt cleaning device 25. The belt cleaning device 25 is provided with, for example, a cleaning blade that contacts the intermediate transfer belt 21 and removes residual toner as a cleaning member, and the back side of the intermediate transfer belt 21 is driven by a driven roller 23 at a portion where the cleaning blade comes into contact. Is supported.

  The recording sheet is conveyed to the fixing device 17 after the color toner image is transferred in the nip region between the intermediate transfer belt 21 and the transfer roller 26 a of the secondary transfer device 26. The fixing device 17 includes a heating roller 31, a pressure roller 32, and the like, and sandwiches and conveys a recording sheet between the heating roller 31 and the pressure roller 32.

  The heating roller 31 is controlled so as to have a predetermined fixing temperature based on a detection output of a temperature detector (not shown), and the color transferred to the recording paper by thermocompression bonding the recording paper together with the pressure roller 32. The toner image is melted, mixed, and pressed, and thermally fixed to the recording paper.

  On the other hand, the paper feed tray 18 is a tray for storing recording paper, and is provided below the image forming apparatus 1 to supply the recording paper in the tray.

  The image forming apparatus 1 has an S-shaped sheet conveyance path S for sending the recording sheet supplied from the sheet feeding tray 18 to the sheet discharge tray 19 via the secondary transfer device 26 and the fixing device 17. Is provided. A set of sheet registration rollers 34, a fixing device 17, a plurality of sets of transfer rollers 35, a set of paper discharge rollers 36, and the like are arranged along the sheet transfer path S.

  A paper pickup roller 33 is provided at the end of the paper feed tray 18, and the recording paper is pulled out from the paper feed tray 18 one by one by the paper pickup roller 33 and conveyed to the paper conveyance path S.

  Each conveyance roller 35 is a small roller for promoting and assisting the conveyance of the recording paper, and is provided at a plurality of locations.

  Each sheet registration roller 34 temporarily stops the recording sheet that has been conveyed, aligns the leading edge of the recording sheet, and in the nip region between the intermediate transfer belt 21 and the transfer roller 26 a of the secondary transfer device 26, the intermediate transfer belt 21. The recording paper is conveyed in a timely manner in accordance with the rotation of each photosensitive drum 13 and the intermediate transfer belt 21 so that the upper color toner image is transferred onto the recording paper.

  Further, the recording paper is fixed with a color toner image by the fixing device 17, passes through the fixing device 17, and is then discharged face down onto the paper discharge tray 19 by each paper discharge roller 36.

  In addition, when printing not only on the front side of the recording paper but also on the back side, the paper discharge rollers 36 are stopped and then rotated in the reverse direction while the recording paper is being conveyed by the paper discharge rollers 36 in the paper conveyance path S. Then, the recording paper is passed through the reversing path Sr, the front and back of the recording paper are reversed, the recording paper is guided to each paper registration roller 34, and the image is recorded and fixed on the back surface of the recording paper in the same manner as the front surface of the recording paper. Then, the recording paper is discharged to the paper discharge tray 19.

  Next, the image reading device 41 and the sheet conveying device 42 mounted on the upper part of the main body of the image forming apparatus 1 will be described. FIG. 2 is an enlarged cross-sectional view showing the image reading device 41 and the paper transport device 42.

  The sheet conveying device 42 is pivotally supported on the inner side of the image reading device 41 by a hinge (not shown) and opened and closed by moving the front portion up and down. When the paper transport device 42 is opened, the platen glass 44 of the image reading device 41 is opened, and a document is placed on the platen glass 44.

  The image reading device 41 includes a platen glass 44, a first scanning unit 45, a second scanning unit 46, an imaging lens 47, a CCD (Charge Coupled Device) 48, and the like. The first scanning unit 45 includes a light source 51 and a first reflecting mirror 52, and exposes a document on the platen glass 44 by the light source 51 while moving at a constant speed V by a distance corresponding to the document size in the sub-scanning direction. Then, the reflected light is reflected by the first reflecting mirror 52 and guided to the second scanning unit 46, thereby scanning the image on the surface of the document in the sub-scanning direction. The second scanning unit 46 includes second and third reflecting mirrors 53 and 54, and follows the first scanning unit 45 while moving at a speed V / 2, while reflecting the reflected light from the document to the second and second. The light is reflected by the three reflecting mirrors 53 and 54 and guided to the imaging lens 47. The imaging lens 47 condenses the reflected light from the document on the CCD 48 and forms an image on the surface of the document on the CCD 48. The CCD 48 repeatedly scans the document image in the main scanning direction, and outputs an analog image signal of one main scanning line each time.

  In addition, the image reading device 41 can read not only a stationary document but also an image on the surface of the document being conveyed by the paper conveying device 42. In this case, the first scanning unit 45 is moved below the original reading glass 55 and the second scanning unit 46 is positioned in accordance with the position of the first scanning unit 45. In this state, the original is conveyed by the paper conveying device 42. To start.

  In the paper transport device 42, the pickup roller 61 is pressed against the document on the document tray 57 and rotated, the document is pulled out, the document is fed to the document transport path 58 by the paper feed roller 62, and the leading edge of the document is temporarily stopped. Then, the registration rollers 63a and 63b start to convey the document, the conveyance rollers 64a and 64b convey the document, and the document is moved to the document reading glass 55. The original is passed between the reading guide plates 56 and conveyed to the paper discharge tray 49 through the reversing rollers 65a and 65b and the paper discharge rollers 66a and 66b.

  When the document is transported, the light source 51 of the first scanning unit 45 illuminates the surface of the document through the document reading glass 55, and the reflected light from the surface of the document is reflected by the reflection mirrors of the first and second scanning units 45 and 46. The light is guided to the imaging lens 47, and the reflected light from the document surface is condensed on the CCD 48 by the imaging lens 47, and an image on the document surface is formed on the CCD 48, thereby reading the image on the document surface.

  When reading the back side of the document, each reversing roller 65a, 65b and each discharge roller 66a is in the middle of discharging the document to the discharge tray 49 through each reverse roller 65a, 65b and each discharge roller 66a, 66b. 66b are temporarily stopped, and then the reversing rollers 65a and 65b and the paper discharge rollers 66a and 66b are rotated in the reverse direction, and the original is guided to the registration rollers 63a and 63b through the reverse conveying path 67, so that the original The front and back sides are reversed, the image on the back side of the document is read in the same manner as the image on the front side of the document, the reversing rollers 65a and 65b and the discharge rollers 66a and 66b are rotated in the forward direction, and the document is rotated on the reversing rollers 65a and 65b. The paper is discharged to the paper discharge tray 49 through the paper discharge rollers 66a and 66b.

  The original image read by the CCD 48 is output from the CCD 48 as an analog image signal, and the analog image signal is A / D converted into a digital image signal (image data). The image data is subjected to various image processing and sent to the optical scanning device 11 of the image forming apparatus 1, where the image is recorded on a recording sheet, and the recording sheet is output as a copy original. Is done.

  Next, the internal structure of the reversing paper conveyance device 42 will be described in more detail. FIG. 3 is a plan view showing the internal structure of the reversible paper transporting device 42 as viewed from above, and FIG. 4 is a perspective view showing the internal structure of the reversing paper transporting device 42 as viewed obliquely from above.

  3 and 4, the inner peripheral guide 71 forms the inner peripheral surface of the document transport path 58 (shown in FIG. 2) and the inner peripheral surface of the reverse transport path 67 (shown in FIG. 2). An outer peripheral guide 72 (shown in FIG. 2) is disposed outside the inner peripheral guide 71, and a document transport path 58 and a reverse transport path 67 are formed between the inner peripheral guide 71 and the outer peripheral guide 72.

  A drive-side registration roller 63 a is provided inside the inner peripheral guide 71, and a part of the drive-side registration roller 63 a protrudes from the opening 71 a of the inner peripheral guide 71. Further, the outer peripheral guide 72 is provided with a driven registration roller 63b, and the driven registration roller 63b is pressed against the driving registration roller 63a through the respective openings 71a.

  Similarly, two driving rollers 64 a (shown in FIG. 2) are provided inside the inner peripheral guide 71, and a part of the two driving rollers 64 a opens the inner peripheral guide 71. It protrudes from the part. Also, the outer peripheral guide 72 is provided with two driven-side transport rollers 64b (shown in FIG. 2), and each driven-side transport roller 64b is pressed against each drive-side transport roller 64a through each opening. ing.

  Reversing rollers 65a and 65b are arranged on the downstream side in the document conveying direction from the inner peripheral guide 71, and further, discharge rollers 66a and 66b (shown in FIG. 2) are arranged on the downstream side.

  Further, on one side of the inner peripheral guide 71, a drive system of the reversible paper transport device 42 is provided. In this drive system, a paper feed motor 73, a transport motor 74, a solenoid 75, a registration roller electromagnetic clutch 76, a reverse roller electromagnetic clutch 77, and the like are provided.

  The paper feed motor 73 rotates the pickup roller 61 and the paper feed roller 62 (shown in FIG. 2). A pulley 81 is fixed to the output shaft of the paper feed motor 73, a pulley 82 is fixed to the shaft 62 a of the paper feed roller 62, and an endless belt 83 is bridged between the pulleys 81, 82. The rotation of the shaft is transmitted to the shaft 62a of the paper feed roller 62 through the pulleys 81 and 82 and the endless belt 83, and the paper feed roller 62 is rotated. Further, the rotation of the paper feed roller 62 is transmitted to the pickup roller 61 through a driving force transmission mechanism that is a combination of a pulley and an endless belt (not shown), thereby rotating the pickup roller 61. The pickup roller 61 is supported so as to be rotatable about the shaft 62 a of the paper feed roller 62. When the paper feed roller 62 and the pickup roller 61 are rotationally driven, a rotational moment is generated around the shaft 62 a of the paper feed roller 62, and the pickup roller 61 rotates and moves around the shaft 62 a of the paper feed roller 62. The document is pressed against the document on the tray 57 and pulled out by the pickup roller 61.

  The conveyance motor 74 rotates the registration rollers 63a and 63b, the conveyance rollers 64a and 64b, the reverse rollers 65a and 65b, and the paper discharge rollers 66a and 66b. The rotational driving force of the output shaft of the conveyance motor 74 is transmitted to the driving side through a driving force transmission mechanism formed by combining a plurality of pulleys (not shown) and a plurality of endless belts (not shown). This is transmitted to the shaft 63c of the registration roller 63a, the shaft (not shown) of the driving-side conveying roller 64a, and the shaft 65c of the driving-side reversing roller 65a, and the driving-side rollers 63a, 64a, 65a rotate. The registration rollers 63a and 63b are always in pressure contact with each other, and when the driving side registration roller 63a is driven to rotate, the driven side registration roller 63b is driven to rotate. The transport rollers 64a and 64b are also always in pressure contact with each other. When the drive-side transport roller 64a is driven to rotate, the driven-side transport roller 64b is driven to rotate. Further, the reversing rollers 65a and 65b are brought into pressure contact with or separated from each other by the movement of the driven reversing roller 65b. The reverse roller 65b is driven to rotate. The driven reversing roller 65 b is moved by a solenoid 75.

  Further, the rotation of the shaft 63c of the driving-side reversing roller 65a is transmitted to the shaft 66c of the driving-side discharge roller 66a through a driving force transmission mechanism including a pulley 68, an endless belt 69, etc. The paper discharge roller 66a is rotated. The paper discharge rollers 66a and 66b are always in pressure contact with each other. When the drive-side paper discharge roller 66a is driven to rotate, the driven-side paper discharge roller 66b is driven to rotate.

  The registration roller electromagnetic clutch 76 is provided at one end of the shaft 63c of the driving side registration roller 63a. The rotation of the output shaft of the transport motor 74 is transmitted to or cut off from the shaft 63c, and the driving side registration roller 63 63a is rotated or stopped. Further, the reverse roller electromagnetic clutch 77 is provided at one end of the shaft 65c of the drive-side reverse roller 65a, and transmits or blocks the rotation of the output shaft of the carry motor 74 to the shaft 65c, thereby driving the reverse roller on the drive side. 65a is rotated or stopped.

  FIG. 5 is a side view showing a mechanism for contacting and separating the driven reversing roller 65b with respect to the driving reversing roller 65a, and FIG. 6 is a perspective view showing the mechanism as viewed obliquely from above. is there.

  5 and 6, the solenoid 75 is mounted and positioned on a frame 84 fixed inside the reversible paper transporting device 42. The solenoid 75 has a plunger 85 that is moved in the arrow direction A to be attracted to the inside of the main body 75a of the solenoid 75, or moved in the arrow direction B to protrude from the main body 75a. The frame 84 is provided with a stopper 87 that faces the tip 85a of the plunger 85. When the plunger 85 protrudes, the tip 85a of the plunger 85 abuts against the stopper 87, and the plunger 85 protrudes. The position is set. Further, an E-ring 86 is fixed to the plunger 85, and when the plunger 85 is sucked, the E-ring 86 comes into contact with the main body 75a, and the suction position of the plunger 85 is set.

  The pin 88 is fixed through the vicinity of the tip of the plunger 85. One end of the pin 88 is inserted into the guide hole 84 a of the frame 84. The guide hole 84a of the frame 84 extends in the moving direction of the plunger 85, guides the pin 88 that moves together with the plunger 85, and inhibits the rotation of the plunger 85.

  The pin 88 is inserted into a long hole 92 a of the lever 92 fixed to one end of the rotating shaft 91. The elongated hole 92a of the lever 92 extends long in the direction orthogonal to the moving direction of the plunger 85 of the solenoid 75. When the pin 88 moves together with the plunger 85, both the elongated holes 92a of the lever 92 are moved by the pin 88. The edge is pushed, the lever 92 rotates around the rotation shaft 91, and the rotation shaft 91 also rotates.

  The rotary shaft 91 is rotatably supported inside the reversible paper conveyance device 42, and the L-shaped arms 93 are rotatably supported at two locations of the rotary shaft 91. Both ends of each torsion coil spring 94 are engaged with each L-shaped arm 93 and the rotating shaft 91, and the urging force of each torsion coil spring 94 acts on each L-shaped arm 93 in the circumferential direction of the rotating shaft 91. To do. A driven reversing roller 65b is rotatably supported at the tip of each L-shaped arm 93.

  The pin 88, the lever 92, the rotating shaft 91, and each L-shaped arm 93 transmit the movement of the plunger 85 of the solenoid 75 to the driven-side reverse roller 65b, so that the driven-side reverse roller 65b is rotated. The link mechanism is configured to rotate and move to the center 91 to switch and set the pressure contact state and the separation state of the reversing rollers 65a and 65b.

  FIG. 7 is a cross-sectional view showing the configuration of the solenoid 75. 7, the solenoid 75 includes a plunger 85, a bobbin 95, a coil 96 wound around the bobbin 95, and a yoke 97 covering the bobbin 95 and the coil 96. The bobbin 95, the coil 96, and A plunger 85 is movably inserted into a hollow hole 98 formed in the center of the yoke 97.

  Here, when a current is passed through the coil 96 and the coil 96 is energized, the plunger 85 moves in the arrow direction A by the magnetic force of the coil 96 and is attracted to the hollow hole 98. In this case, as shown in FIG. 8, the lever 92 rotates clockwise about the rotation shaft 91, and the rotation shaft 91 and each L-shaped arm 93 also rotate clockwise, and the leading end of each L-shaped arm 93 is driven. The reverse roller 65b on the side is lifted and comes into contact with the reverse roller 65a on the drive side. Then, after the driven reversing roller 65b comes into contact with the driving reversing roller 65a, the rotating shaft 91 further rotates in the clockwise direction against the urging force of each torsion coil spring 94 with respect to each L-shaped arm 93. A biasing force is generated in each torsion coil spring 94, and the biasing force of each torsion coil spring 94 biases the driven reversing roller 65b at the tip of each L-shaped arm 93 in the clockwise direction and presses against the driving reversing roller 65a. The In this state, when the driving-side reversing roller 65a is driven to rotate, the driven-side reversing roller 65b is driven to rotate.

  When the energization of the coil 96 is turned off, the plunger 85 is in a movable state. Here, when energization of the coil 96 is on, the reversing roller 65b on the driven side at the tip of each L-shaped arm 93 with respect to the rotating shaft 91 is watched by the urging force of each torsion coil spring 94 as shown in FIG. Since the energization of the coil 96 is switched from on to off, the driven reversing roller 65b protrudes from the driving reversing roller 65a as shown in FIG. 5 and FIG. Rotate around. Each L-shaped arm 93 is further rotated counterclockwise around the rotation shaft 91 by its own weight, and the driven-side reverse roller 65b is separated from the drive-side reverse roller 65a. Accordingly, the rotation shaft 91 and the lever 92 also rotate counterclockwise, and the plunger 85 moves in the arrow direction B and protrudes from the hollow hole 98.

  Accordingly, when energization of the coil 96 of the solenoid 75 is turned on, the plunger 85 is attracted in the arrow direction A by the magnetic force of the coil 96, and at this time, the lever 92, the rotary shaft 91, and each L-shaped arm 93 are Rotating in the rotating direction, the driven reversing roller 65b comes into contact with the driving reversing roller 65a, and an urging force is generated in each torsion coil spring 94. The urging force of each torsion coil spring 94 causes the driven reversing roller 65b to move. It is pressed against the reverse roller 65a on the driving side. When the energization of the coil 96 is switched from on to off, the driven reversing roller 65b protrudes from the driving reversing roller 65a by the urging force of each torsion coil spring 94 and rotates counterclockwise. The mold arm 93 is further rotated counterclockwise by its own weight, the driven reversing roller 65b is separated from the driving reversing roller 65a, and the rotating shaft 91 and the lever 92 are also rotated counterclockwise. The jar 85 protrudes in the arrow direction B.

  Next, referring to a side view of the reversing paper transporting device 42 shown in FIG. 9, an outline of the document transporting operation by the reversing paper transporting device 42 and the operation for reversing the front and back of the document will be described.

  First, the paper feed motor 73 is rotated, and the paper on the document tray 57 is pulled out by the paper feed roller 62 and the pickup roller 61 and sent out to the document transport path 58. At this time, while the conveyance motor 74 is rotating forward, the registration roller electromagnetic clutch 76 is disconnected, the registration rollers 63a and 63b are temporarily stopped, and the leading edge of the original is abutted against the registration rollers 63a and 63b. Align.

  Then, the registration roller electromagnetic clutch 76 is connected, the registration rollers 63a and 63b are rotated, and the conveyance of the original is started. Further, the original is conveyed by the respective conveyance rollers 64a and 64b, and the original is read with the original reading glass 55. Pass between the reading guide plates 56. Further, the energization of the coil 96 of the solenoid 75 is turned on, the driven reversing roller 65b is brought into pressure contact with the driving reversing roller 65a, and the reversing roller electromagnetic clutch 77 is connected to each reversing roller 65a, 65b and each paper discharge. By rotating the rollers 66a and 66b, the original is conveyed to the paper discharge tray 49 through the reversing rollers 65a and 65b and the paper discharge rollers 66a and 66b, and discharged.

  Further, when reading the back side of the document by reversing the front and back sides of the document, the transport motor 74 is in the process of discharging the document W to the discharge tray 49 through the reverse rollers 65a and 65b and the discharge rollers 66a and 66b. Are stopped, the reversing rollers 65a and 65b and the paper discharge rollers 66a and 66b are stopped, and then the transport motor 74 is reversely rotated so that the reverse rollers 65a and 65b and the paper discharge rollers 66a and 66b are moved in the reverse direction. The original W is conveyed to the registration rollers 63a and 63b through the reverse conveyance path 67 and returned. At this time, the registration roller electromagnetic clutch 76 is disconnected, the registration rollers 63a and 63b are temporarily stopped, and the trailing edge of the original W is brought into contact with the registration rollers 63a and 63b to be aligned.

  Further, the transport motor 74 is temporarily stopped and the transport motor 74 is rotated forward again. Then, during the period from the stop of the conveyance motor 74 to the normal rotation again, the registration roller electromagnetic clutch 76 is connected to enable the rotation of the registration rollers 63a and 63b. Further, following the start of forward rotation of the transport motor 74 again, the energization of the coil 96 of the solenoid 75 is turned off, the driven reversing roller 65b is separated from the driving reversing roller 65a, and the reversing roller electromagnetic clutch 77 is disconnected. Thus, the reversing rollers 65a and 65b and the paper discharge rollers 66a and 66b are rotatable. As a result, the registration rollers 63a and 63b are driven to rotate and the conveyance of the original W is started. At the same time, the reverse roller 65a on the driving side and the respective discharge rollers 66a and 66b are rotated around the original W, thereby W can be pulled out in the reverse direction from each of the reversing rollers 65a and 65b and each of the paper discharge rollers 66a and 66b, so that the original W can be conveyed quickly.

  Thereafter, similarly to the above, the document W is transported by the transport rollers 64 a and 64 b, and the document W is passed between the document reading glass 55 and the reading guide plate 56. Further, the energization of the coil 96 of the solenoid 75 is turned on, the driven reversing roller 65b is brought into pressure contact with the driving reversing roller 65a, and the reversing roller electromagnetic clutch 77 is connected to each reversing roller 65a, 65b and each paper discharge. The rollers 66a and 66b are rotated in the forward direction, and the original W is conveyed to the paper discharge tray 49 through the reversing rollers 65a and 65b and the paper discharge rollers 66a and 66b and discharged.

  By the way, when the document is transported in the opposite direction so as to reverse the front and back of the document, the energization of the coil 96 of the solenoid 75 is switched from on to off, and the energization is switched from off to on. As shown in FIG. 8, the plunger 85 moves in the arrow direction B and protrudes from the hollow hole 98, the tip 85a of the plunger 85 collides with the stopper 87, or the plunger 85 moves in the arrow direction A as shown in FIG. Then, the E-ring 86 of the plunger 85 collides with the main body 75a of the solenoid 75, so that a large noise is generated unless the impact due to the collision is alleviated.

  Therefore, in the paper transport device 42 of this embodiment, the width of the current pulse supplied to the coil 96 of the solenoid 75 is controlled to gradually change the magnetic force of the coil 96, thereby controlling the moving speed of the plunger 85. Then, the impact of the tip 85a of the plunger 85 on the stopper 87 and the impact of the E-ring 86 of the plunger 85 on the main body 75a of the solenoid 75 are alleviated to reduce the collision sound.

  Next, the control and operation of such a solenoid 75 will be described. FIG. 10 is a block diagram showing a control system such as a solenoid 75 in the paper transport device 42.

  10, a plurality of sensors 101a, 101b, 101c,... Detect the presence or absence of a document on the document tray 57, and detect the positions of the leading and trailing edges of the document at a plurality of locations on the document transport path 58. These detection outputs are output to the control unit 102. The control unit 102 drives and controls the paper feed motor 73, the transport motor 74, the solenoid 75, the registration roller electromagnetic clutch 76, the reverse roller electromagnetic clutch 77, and the like based on the detection output of each sensor 101a,. It is pulled out from the document tray 57 and conveyed.

  For example, when the document on the document tray 57 is detected by the sensor 101a, the control unit 102 rotates the paper feed motor 73 and pulls the document from the document tray 57 by the paper feed roller 62 and the pickup roller 61 to convey the document. Deliver to path 58. When the leading edge of the document is detected by the sensor 101b upstream of the registration rollers 63a and 63b in the document conveyance direction, the control unit 102 connects the registration roller electromagnetic clutch 76 based on this detection timing, and The conveyance of the original by the rollers 63a and 63b is started.

  Further, when reading the back side of the document by reversing the front and back sides of the document, the control unit 102 detects the trailing edge of the document by the sensor 101c upstream of the reversing rollers 65a and 65b in the document transport direction. The conveyance motor 74 is stopped, the conveyance motor 74 is rotated in the reverse direction, the reversing rollers 65 a and 65 b and the paper discharge rollers 66 a and 66 b are rotated in the reverse direction, and the original is transferred to the registration rollers 63 a and 63 b through the reversing conveyance path 67. And carry. Then, the registration roller electromagnetic clutch 76 is disconnected, and the trailing edge of the document is brought into contact with the registration rollers 63a and 63b to be aligned. Subsequently, the conveyance motor 74 is rotated forward again, the registration roller electromagnetic clutch 76 is connected, the conveyance of the original by the registration rollers 63a and 63b is started, and the energization of the coil 96 of the solenoid 75 is turned off to be driven. The reversing roller 65b on the side is separated from the reversing roller 65a on the driving side, the reversing roller electromagnetic clutch 77 is disconnected, and the document can be pulled out from the reversing rollers 65a and 65b and the discharge rollers 66a and 66b in the reverse direction. To. Further, the original is conveyed again by the respective conveying rollers 64a and 64b, the energization of the coil 96 of the solenoid 75 is turned on, the driven reverse roller 65b is pressed against the driving reverse roller 65a, and the reverse roller electromagnetic clutch 77 is set. The reversing rollers 65a and 65b and the paper discharge rollers 66a and 66b are rotated in the forward direction so that the original is conveyed to the paper discharge tray 49 and discharged.

  On the other hand, the control unit 102 gradually changes the magnetic force of the coil 96 by controlling the width of the current pulse supplied to the coil 96 of the solenoid 75 when the energization of the coil 96 of the solenoid 75 is switched on and off. Thus, the moving speed of the plunger 85 is controlled.

  FIG. 11A is a waveform diagram showing a current pulse supplied to the coil 96 when the plunger 85 is attracted.

  As shown in FIG. 11A, when the current I supplied to the coil 96 is “0” (when the energization of the coil 96 is off), the plunger 85 protrudes and the current pulse PI is supplied to the coil 96. Is started (when energization of the coil 96 is turned on), the suction operation of the plunger 85 is started.

  When the plunger 85 is attracted, as shown in FIG. 11A, the current pulse PI having the current value i is supplied to the coil 96, and the width d of the current pulse PI is set from 2 ms (milliseconds) to 9 ms. 1 ms is spread in 9 stages, and thereafter, the current I having the same current value i as the current pulse PI is continuously supplied to the coil 96 to continuously turn on the coil 96.

  Also, a current pulse PI with a width d of 2 ms is supplied five times, a current pulse PI with a width d of 3 ms is supplied four times, a current pulse PI with a width d of 4 ms is supplied three times, and a current d with a width d of 5 ms is supplied. The pulse PI is supplied twice, and the current pulses PI with widths d of 6 ms, 7 ms, 8 ms, and 9 ms are supplied once each. Further, the off period Δf between the current pulses PI is set to a constant 1 ms.

  FIG. 11B is a chart in which the width d of the current pulse PI, the number of current pulses PI, and the off period Δf are organized. 12A, 12B, and 12C schematically show the main body 75a of the solenoid 75, the coil 96, the plunger 85, the E ring 86, the stopper 87, each torsion coil spring 94, and the like.

  Here, when a current pulse PI as shown in FIGS. 11A and 11B is supplied to the coil 96 of the solenoid 75 with the plunger 85 protruding as shown in FIG. As shown in FIG. 8, the reversing roller 65b on the driven side at the tip of each L-shaped arm 93 is lifted and the reversing roller 65a on the driving side is lifted. The rotating shaft 91 further rotates in the clockwise direction against the biasing force of each torsion coil spring 94 with respect to each L-shaped arm 93, and a biasing force is generated in each torsion coil spring 94. At this time, the balance between the attracting force of the plunger 85 by the magnetic force of the coil 96 (force that rotates the rotating shaft 91 clockwise) and the biasing force of each torsion coil spring 94 (force that rotates the rotating shaft 91 counterclockwise). When it is removed, the plunger 85 is half-sucked as shown in FIG. When the magnetic force of the coil 96 is further increased and the suction of the plunger 85 is further increased, the plunger 85 is completely attracted against the biasing force of each torsion coil spring 94 as shown in FIG. The E-ring 86 of the plunger 85 abuts against the main body 75a of the solenoid 75.

  Therefore, by supplying a current pulse PI as shown in FIGS. 11A and 11B to the coil 96, the plunger 85 is gradually moved against the urging force of each torsion coil spring 94 and sucked. While the plunger 85 is sucked, the moving speed of the plunger 85 is suppressed, the impact of the E-ring 86 of the plunger 85 on the main body 75a of the solenoid 75 is reduced, and the collision sound can be reduced. . In addition, since the current I having the current value i as shown in FIGS. 11A and 11B is continuously passed through the coil 96 after the plunger 85 is completely sucked, the plunger 85 is completely sucked. The stable state can be maintained stably.

  Next, FIG. 13A shows a waveform indicating a current pulse supplied to the coil 96 when the energization of the coil 96 is switched from on to off and the plunger 85 protrudes by the urging force of each torsion coil spring 94. FIG.

  As shown in FIG. 13A, when the current value of the current I supplied to the coil 96 is i (when the coil 96 is energized), the plunger 85 is attracted. When the plunger 85 protrudes, as shown in FIG. 13A, the energization of the coil 96 is turned off for a certain period T (the current value of the current I is set to “0”). While the current pulse PI of the current value i with respect to is supplied, the width d of the current pulse PI is narrowed in 6 steps by 1 ms from 7 ms (milliseconds) to 2 ms, and the current I supplied to the coil 96 is changed to “ It is set to “0” and the energization of the coil 96 is continuously turned off.

  Further, a current pulse PI having a width d of 7 ms, 6 ms, 5 ms, 4 ms, and 3 ms is supplied once, and a current pulse PI having a width d of 2 ms is supplied 20 times. Further, the off period Δf between the current pulses PI is set to a constant 1 ms.

  FIG. 13B is a chart in which the width d of the current pulse PI, the number of current pulses PI, and the off period Δf are organized.

  Here, with respect to the coil 96 of the solenoid 75 in a state where the plunger 85 as shown in FIG. 12 (c) is attracted, the energization of the coil 96 is fixed as shown in FIGS. 13 (a) and 13 (b). When it is turned off only for the period T, the magnetic force of the coil 96 disappears for the certain period T, and the plunger 85 starts to move and project due to the urging force of each torsion coil spring 94. That is, the urging force of each torsion coil spring 94 causes the driven reversing roller 65b to project the driving reversing roller 65a to rotate counterclockwise, and the rotation shaft 91 and the lever 92 rotate counterclockwise. The plunger 85 moves and begins to protrude. When a current pulse PI as shown in FIGS. 13A and 13B is supplied to the coil 96 of the solenoid 75 immediately after the start of the movement of the plunger 85, the magnetic force of the coil 96 attracts the plunger 85. Therefore, the moving speed of the protruding plunger 85 is suppressed (the brake is applied to the plunger 85), and the plunger 85 protrudes halfway as shown in FIG. When the magnetic force of the coil 96 is further reduced, the plunger 85 protrudes completely by the urging force of each torsion coil spring 94 as shown in FIG. 12A, and the tip 85a of the plunger 85 abuts against the stopper 87.

  Therefore, the plunger 85 that is protruding by the urging force of each torsion coil spring 94 can be gradually moved, and while the plunger 85 is protruded, the moving speed of the plunger 85 is suppressed and the plunger 85 with respect to the stopper 87 is suppressed. It is possible to reduce the impact of the front end 85a and reduce the impact sound. Further, after the plunger 85 has completely protruded, the current I flowing through the coil 96 is set to “0” as shown in FIGS. 13A and 13B. It can be maintained stably.

  As described above, in the paper conveyance device 42 of the present embodiment, when the plunger 85 is attracted, the current pulse PI is supplied to the coil 96, and the width d of the current pulse PI is increased from 2 ms to 9 ms in 9 steps by 1 ms. Each time the current pulse PI having a width d of 2 ms is supplied five times and the width d of the current pulse PI is expanded stepwise, the number of current pulses PI is decreased, and the width d is 6 ms, 7 ms, Since the current pulses PI of 8 ms and 9 ms are supplied once each, the moving speed of the plunger 85 is suppressed while the plunger 85 is sucked, and the E-ring 86 of the plunger 85 with respect to the body 75a of the solenoid 75 is suppressed. The impact noise can be reduced and the impact sound can be reduced. When the plunger 85 protrudes, the energization of the coil 96 is turned off for a certain period T, and the current pulse PI of the current value i is continuously supplied to the coil 96, while the width d of the current pulse PI is increased from 7 ms to 2 ms. Narrowing by 1 ms in 6 steps, supplying current pulse PI with width d of 7 ms, 6 ms, 5 ms, 4 ms, 3 ms once each and supplying current pulse PI with width d of 2 ms 20 times Therefore, while the plunger 85 is projected, the moving speed of the plunger 85 can be suppressed, the impact of the tip 85a of the plunger 85 on the stopper 87 can be reduced, and the collision sound can be reduced.

  For both the suction and the protrusion of the plunger 85, the width d of the current pulse PI, the number of the current pulses PI, and the off period Δf are the magnetic force of the coil 96, the urging force of each torsion coil spring 94, and the plunger 85 It should be set appropriately according to the movement distance, and is not limited to the above embodiment. Similarly, when the plunger 85 protrudes, the energization of the coil 96 is turned off for a certain period T. The length of the certain period T also depends on the magnetic force of the coil 96, the urging force of each torsion coil spring 94, and the plunger 85. It should be set appropriately according to the movement distance of and is not limited to the above embodiment.

  Further, the step of changing the width d of the current pulse PI is preferably three or more steps, which makes it easy to reproduce the state in which the plunger 85 as shown in FIG. Further, the number of current pulses PI is preferably increased when the width d of the current pulse PI is short, so that the movement of the plunger 85 can be controlled even when the width d of the current pulse PI is short. Become.

  Further, the solenoid control device of the present invention can be applied not only to the sheet conveying apparatus 42 that conveys a document but also to the image forming apparatus 1 that conveys a recording sheet. For example, when a solenoid is used to switch and set each of the paper discharge rollers 36 in the image forming apparatus 1 of FIG. 1 between the pressure contact state and the separation state, the solenoid control device of the present invention can be applied.

  Furthermore, the present invention includes not only a solenoid control device but also a paper conveying device and an image forming device.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. It is understood.

DESCRIPTION OF SYMBOLS 1 Image forming device 11 Optical scanning device 12 Developing device 13 Photosensitive drum 14 Drum cleaning device 15 Charger 16 Intermediate transfer belt device 17 Fixing device 18 Paper feed tray 19 Paper discharge tray 41 Image reading device 42 Paper transport device 44 Platen glass 45 First scanning unit 46 Second scanning unit 47 Imaging lens 48 CCD
51 Light source 55 Document reading glass 56 Reading guide plate 57 Document tray 58 Document transport path 61 Pickup roller 62 Paper feed rollers 63a, 63b Registration rollers 64a, 64b Transport rollers 65a, 65b Reverse rollers (drive roller, driven roller)
66a, 66b Paper discharge roller 67 Reverse conveyance path 71 Inner circumference guide 72 Outer circumference guide 73 Paper feed motor 74 Carry motor 75 Solenoid 76 Registration roller electromagnetic clutch 77 Reverse roller electromagnetic clutch 85 Plunger 86 E ring 87 Stopper 88 Pin (link mechanism)
91 Rotating shaft (link mechanism)
92 Lever (link mechanism)
93 L-shaped arm 93 (link mechanism)
94 Torsion coil spring (biasing member)
95 Bobbin 96 Coil 101a, 101b, 101c Sensor 102 Control unit

Claims (12)

A solenoid control device that controls a solenoid that attracts a plunger by the magnetic force of a coil,
A controller for gradually increasing the magnetic force of the coil by gradually increasing the width of the pulse supplied to the coil when the plunger is attracted;
The solenoid control device according to claim 1, wherein the plunger receives an urging force in a protruding direction during the suction process, and is attracted against the urging force by a magnetic force of the coil. The solenoid control device according to claim 1,
The control unit increases the number of pulses having a width set at the time of disclosing the supply of pulses to the coil, and when the width of the pulses is increased stepwise, the number of pulses is set to the width of the previous step. A solenoid control device characterized by reducing the number of pulses. The solenoid control device according to claim 1 or 2,
The solenoid control device, wherein the controller continuously turns on the energization of the coil after the pulse width is maximized. The solenoid control device according to any one of claims 1 to 3,
The said control part maintains the OFF period between the said pulses shorter than the width | variety of the said pulse, and is constant, The solenoid control apparatus characterized by the above-mentioned. The solenoid control device according to any one of claims 1 to 4,
The said control part makes the width | variety of the said pulse gradually 3 steps or more, and increases the magnetic force of the said coil sequentially, The solenoid control apparatus characterized by the above-mentioned. A solenoid control device that controls a solenoid that attracts a plunger by a magnetic force of a coil, causes the plunger to protrude by an urging force of an urging member, and limits a protruding amount of the plunger by a stopper,
With the plunger sucked by continuously turning on the current to the coil, the current to the coil is turned off for a certain period, and then the width of the pulse supplied to the coil is gradually reduced. And the solenoid control apparatus provided with the control part which reduces the magnetic force of the said coil sequentially. The solenoid control device according to claim 6,
The said control part increases the number of the said pulses from the number of the pulses of the width | paragraph of 1 step before when the width | variety of the said pulse is narrowed in steps, The solenoid control apparatus characterized by the above-mentioned. The solenoid control device according to claim 6 or 7,
The said control part turns off the electricity supply to the said coil, after narrowing the width | variety of the said pulse, The solenoid control apparatus characterized by the above-mentioned. The solenoid control device according to any one of claims 6 to 8, wherein
The said control part maintains the OFF period between the said pulses shorter than the width | variety of the said pulse, and is constant, The solenoid control apparatus characterized by the above-mentioned. The solenoid control device according to any one of claims 6 to 9,
The said control part narrows the width | variety of the said pulse in three steps or more in steps, and reduces the magnetic force of the said coil sequentially, The solenoid control apparatus characterized by the above-mentioned. A paper conveying device that includes a driving roller and a driven roller that is set to switch between a pressure contact state and a separation state with respect to the driving roller, and conveys a paper sheet sandwiched between the driving roller and the driven roller that are in pressure contact with each other. ,
The solenoid control device according to any one of claims 1 to 10,
A link mechanism that transmits the movement of the plunger of the solenoid control device to the driven roller, moves the driven roller, and switches between a pressure contact state and a separation state of the driven roller with respect to the drive roller. Paper transport device.   An image forming apparatus comprising the paper transport device according to claim 11, wherein a paper or a recording paper is transported by the paper transport device.

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